WO2008032588A1 - Document illuminating method, document illuminating device, and image reader - Google Patents

Document illuminating method, document illuminating device, and image reader Download PDF

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Publication number
WO2008032588A1
WO2008032588A1 PCT/JP2007/067009 JP2007067009W WO2008032588A1 WO 2008032588 A1 WO2008032588 A1 WO 2008032588A1 JP 2007067009 W JP2007067009 W JP 2007067009W WO 2008032588 A1 WO2008032588 A1 WO 2008032588A1
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WO
WIPO (PCT)
Prior art keywords
light
illumination
imaging
lens
light source
Prior art date
Application number
PCT/JP2007/067009
Other languages
French (fr)
Japanese (ja)
Inventor
Satoshi Yamauchi
Original Assignee
Oisllee Planning Co., Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Oisllee Planning Co., Ltd filed Critical Oisllee Planning Co., Ltd
Priority to JP2008534290A priority Critical patent/JP4438015B2/en
Publication of WO2008032588A1 publication Critical patent/WO2008032588A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/024—Details of scanning heads ; Means for illuminating the original
    • H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
    • H04N1/02815—Means for illuminating the original, not specific to a particular type of pick-up head
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/024—Details of scanning heads ; Means for illuminating the original
    • H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
    • H04N1/02815—Means for illuminating the original, not specific to a particular type of pick-up head
    • H04N1/02845—Means for illuminating the original, not specific to a particular type of pick-up head using an elongated light source, e.g. tubular lamp, LED array
    • H04N1/0285—Means for illuminating the original, not specific to a particular type of pick-up head using an elongated light source, e.g. tubular lamp, LED array in combination with at least one reflector which is in fixed relation to the light source
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/024—Details of scanning heads ; Means for illuminating the original
    • H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
    • H04N1/02815—Means for illuminating the original, not specific to a particular type of pick-up head
    • H04N1/02845—Means for illuminating the original, not specific to a particular type of pick-up head using an elongated light source, e.g. tubular lamp, LED array
    • H04N1/02865—Means for illuminating the original, not specific to a particular type of pick-up head using an elongated light source, e.g. tubular lamp, LED array using an array of light sources or a combination of such arrays, e.g. an LED bar
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/024—Details of scanning heads ; Means for illuminating the original
    • H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
    • H04N1/02815—Means for illuminating the original, not specific to a particular type of pick-up head
    • H04N1/02885—Means for compensating spatially uneven illumination, e.g. an aperture arrangement
    • H04N1/0289—Light diffusing elements, e.g. plates or filters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/10—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using flat picture-bearing surfaces
    • H04N1/1013—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using flat picture-bearing surfaces with sub-scanning by translatory movement of at least a part of the main-scanning components
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/19—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays
    • H04N1/191—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays the array comprising a one-dimensional array, or a combination of one-dimensional arrays, or a substantially one-dimensional array, e.g. an array of staggered elements
    • H04N1/192—Simultaneously or substantially simultaneously scanning picture elements on one main scanning line
    • H04N1/193—Simultaneously or substantially simultaneously scanning picture elements on one main scanning line using electrically scanned linear arrays, e.g. linear CCD arrays

Definitions

  • the present invention relates to a document illumination method, a document illumination device, and an image reading device.
  • Patent Document 1 discloses an image reading apparatus that reads reflected image from a document illuminated by a light source onto an imaging element with an imaging lens and reads the image of the document.
  • an image reading apparatus characterized in that the light source is provided at a position that overlaps a part of an effective pupil of the imaging lens when the imaging lens is viewed! .
  • Patent Document 2 discloses an image reading apparatus that illuminates a document surface with a one-dimensional light source and scans the document to read a document image line-sequentially with a one-dimensional imaging device and an imaging lens.
  • a half mirror that guides the light from the one-dimensional light source to the imaging lens between the imaging element and the imaging lens, and the perpendicular of the document surface coincides with the optical axis of reading by the imaging lens.
  • An image reading apparatus characterized in that the optical system is configured so as not to occur is disclosed.
  • FIGS. 1A and 1B are a schematic view of a general image reading apparatus and a cross-sectional view of the image reading apparatus in the sub-scanning direction, respectively.
  • an original (107) such as a sheet and a book is placed on a contact glass (original table) (108) made of transparent glass, and the light from the illumination lamp (109) and Light reflected from the reflector (110) receiving light leaked from the illumination lamp (109) is applied to the imaging area (Ai) of the document (107).
  • the illumination lamp (109) is, for example, a cold cathode tube, and a part of the tube wall is a window. The light from the illumination lamp (109) is applied to the imaging area (Ai) of the document (107) through the window.
  • the first traveling body (103) integrally includes an illumination lamp (109), a reflector (110), and a turning mirror (112), and the second traveling body (104) includes a folding mirror A (l 11a) and folding mirror B (11 lb).
  • the reflected light from the imaging region (Ai) is reflected by the turning mirror (112) in the first traveling body (103), the folding mirror A (11 la) and the folding mirror B (in the second traveling body (104).
  • 11 lb) and is imaged on the one-dimensional image sensor (101) by the imaging lens (102).
  • the folding mirror A (l 11a) and the folding mirror B (11 lb) maintain the direction of the image of the reflected light from the turning mirror (112).
  • the imaging lens (102) is generally an optical system including a plurality of lenses integrated by a lens barrel.
  • the one-dimensional imaging device (101) acquires a one-dimensional image of the line-shaped imaging region (Ai) and converts it into an electrical signal.
  • the direction in which the one-dimensional image sensor (101) acquires this one-dimensional image is called the main scanning direction (Sx).
  • a system including the imaging lens (102) and the one-dimensional image sensor may be referred to as a reading unit.
  • the reading area of the document (107) is the product of the range read by the one-dimensional imaging device (101) and the traveling distance of the second traveling body (104).
  • a direction in which the first traveling body (103) and the second traveling body (104) travel in parallel with the contact glass (108) is referred to as a sub-scanning direction (Sy).
  • the sub-scanning direction (Sy) is orthogonal to the main scanning direction (Sx).
  • a one-dimensional CCD (sometimes simply referred to as a CCD) is used as a one-dimensional imaging device, and the imaging lens (102) reduces the image on the surface of the contact glass (108), and The reduced image is formed on the one-dimensional image sensor (101).
  • the moving distance of the second traveling body (104) is Half of the travel distance of the first traveling body (103), from the imaging area (Ai) to the imaging lens (102) or the one-dimensional imaging device (101) Is constant regardless of the positions of the first traveling body (103) and the second traveling body (104).
  • a monochrome scanner uses a single one-dimensional CCD, and the image resolution of the scanner is expressed in DPI (dots / inch), and the image resolution of the scanner installed in a digital PPC. Is often 400-600 DPI.
  • color scanners use three one-dimensional CCDs that are sensitive to the spectrum of R (red), G (green), or B (blue) light. It is common.
  • a three-line CCD with a color filter for lateral force, sinusoidal force (red), G (green) or B (blue) arranged in the sub-scanning direction (Sy) is used as the image sensor. Sometimes.
  • the distance between the pixel columns is about 4 to 8 dots in the main scanning reading area of the CCD pixel, and the pixel columns are not necessarily integrated. Therefore, when a 3-line CCD is used as the image sensor of the image reading device, the reading position of the original corresponding to each of the RGB CCD pixels differs in the secondary scanning direction (Sy). It is necessary to irradiate the reading position corresponding to each color.
  • FIG. 2 is a diagram for explaining one of the problems related to illumination of a document in the image reading apparatus.
  • the light generated in the cold-cathode tube illumination lamp (201) mounted on the first traveling body of the image reading device is reflected by the fluorescent screen (202) and passes through the opening (203) of the cold-cathode tube. , Emitted as illumination light (204).
  • the illumination light (204) emitted from the illumination lamp (201) directly illuminates the imaging area (Ai) of the document placed on the contact glass (205), or the reflector mounted on the first traveling body ( 206) to reflect the imaging area (Ai) of the document.
  • Fig. 2 shows the illuminance distribution (Di) of the illumination light (204) in the vicinity of the imaging region (Ai).
  • the illumination light that illuminates the imaging area (Ai) by (206) is less than 1% of the amount of light generated in the cold-cathode tube illumination lamp (201), and is imaged by the illumination lamp (201) and reflector (207).
  • the efficiency of illuminating area (Ai) is very low.
  • the length of the imaging area (Ai) in the sub-scanning direction (Sy) is about 0.1 mm wide when using a 1-line CCD. When a 3-line CCD is used to read a color document, it is about 1 mm. Nevertheless, the illuminance distribution (Di) of the illumination light (204) in the sub-scanning direction (Sy) spreads over a wide range of several tens of mm centering on the imaging area (Ai).
  • FIG. 3 is a diagram for explaining another problem relating to illumination of a document in the image reading apparatus.
  • Fig. 3 when reading a book document (302) placed on the contact glass (301), the illuminance by the illumination light (303) directly illuminated from the illumination lamp is less than the illuminance by the reflected light from the reflector. Because it is several times higher, the reading position of the central part (304) of the book original (302) is insufficient in illuminance, and the central part (304) of the book original (302) is read as a black image. (Ad) may occur.
  • FIG. 4 is a diagram illustrating a light source composed of a plurality of LEDs and illumination by the light source.
  • FIG. 4 (a) is a diagram showing a single LED chip constituting the light source.
  • FIG. 4 (b) is a diagram for explaining the configuration of a light source composed of a plurality of LEDs.
  • FIG. 4 (c) is a diagram illustrating the illuminance distribution in the imaging region (Ai) illuminated by a light source composed of a plurality of LEDs.
  • an LED chip cut into a rectangle having a longitudinal direction (VI) and a lateral direction (Vs) is used.
  • a plurality of LED chips are aligned in the longitudinal direction (VI) of the LED chip as shown in FIG. 4 (a) to form a light source.
  • the light source is such that the direction in which the plurality of LEDs are aligned (longitudinal direction of the plurality of LEDs) is the main scanning direction (Sx) of the one-dimensional image sensor, and the short direction of the plurality of LEDs is
  • the one-dimensional imaging device is arranged so as to be in the sub-scanning direction (Sy).
  • the illumination target area (Ai) is illuminated using a light source composed of a plurality of LEDs arranged in this way.
  • the difference in the amount of light emission between the individual LEDs directly causes the illuminance unevenness of the illumination light by the light source.
  • shading correction is known as a technique for correcting slight illuminance unevenness.
  • the entire white part is scanned once in the main scanning direction (Sx), and the brightness distribution of the actually scanned document is electrically measured based on the brightness distribution in the scanned all white part. It can be corrected.
  • the LED luminous efficiency will vary more than twice. As shown in Fig.
  • the signal for the part illuminated with lower illuminance becomes a signal containing magnitude noise, which degrades the quality of the read signal.
  • selecting multiple LEDs with little or no variation in luminous efficiency will greatly reduce the yield of light sources composed of multiple LEDs, resulting in several times the cost increase. .
  • Patent Document 1 JP 2005-204272 A
  • Patent Document 2 JP-A-2005-242263
  • a first object of the present invention is to provide a document illumination method capable of illuminating a document with higher efficiency with light emitted from a light source.
  • a second object of the present invention is to provide a document illuminating device capable of illuminating a document with higher efficiency by light emitted from a light source.
  • a third object of the present invention is to provide an image reading apparatus that reads an image of a document illuminated by a document illumination device capable of illuminating the document with light emitted from a light source with higher efficiency. That is. Means for solving the problem
  • a first aspect of the present invention is a document illumination method for illuminating a document with light emitted from a light source, wherein light emitted from a plurality of light sources arranged at least in a first direction is superimposed. Illuminating the original with the superimposed light, and the light flux emitted from the plurality of light sources in the first direction with a distance between adjacent light sources in the plurality of light sources.
  • An original illumination method including diffusing twice or more.
  • a second aspect of the present invention is a document illumination device that illuminates a document with light emitted from a light source, and a plurality of light sources arranged in at least a first direction, and the plurality of light sources emitted from the plurality of light sources. And illuminating the original with the superimposed light, and causing the light flux emitted from the plurality of light sources to emit light beams adjacent to each other in the plurality of light sources in the first direction.
  • An original illuminating device including an optical system for diffusing at least twice the distance between the two.
  • a third aspect of the present invention includes an original illuminating apparatus that illuminates an original with light emitted from a light source, and an image reading apparatus that reads an image of the original illuminated by the original illuminating apparatus.
  • the illumination device superimposes a plurality of light sources arranged in at least a first direction and light emitted from the plurality of light sources to illuminate a document with the superimposed light, and the plurality of light sources
  • An image reading apparatus comprising: an optical system for diffusing a light beam emitted from a light source in the first direction to at least twice an interval between adjacent light sources in the plurality of light sources. It is.
  • a fourth aspect of the present invention provides a plurality of light sources arranged in at least a first direction, and superimposes light emitted from the plurality of light sources, and illuminates a document with the superimposed light.
  • an original illuminating apparatus including an illumination optical system that diffuses the light flux of light emitted from the plurality of light sources in the first direction more than a distance between adjacent light sources in the plurality of light sources,
  • An image of the original including an imaging optical system that forms an image scattered or reflected from the original illuminated by the original illuminating device, and an imaging element that images the light imaged by the imaging optical system
  • the plurality of light sources has an illuminance distribution characteristic of light illuminating the original on the original opposite to a brightness distribution characteristic of an image formed on the image sensor by the imaging optical system. Is arranged to be This is an image reading apparatus.
  • the first aspect of the present invention it is possible to provide a document illumination method capable of illuminating a document with higher efficiency by light emitted from a light source.
  • the second aspect of the present invention it is possible to provide a document illumination device capable of illuminating a document with higher efficiency by light emitted from a light source.
  • the image reading device reads an image of the original illuminated by the original illumination device capable of illuminating the original with higher efficiency by the light emitted from the light source. Can be provided.
  • the image reading device reads an image of the original illuminated by the original illumination device capable of illuminating the original with higher efficiency by the light emitted from the light source. Can be provided.
  • FIGS. 1A and 1B are a schematic view of a general image reading apparatus and a cross-sectional view of the image reading apparatus in the sub-scanning direction, respectively.
  • FIG. 2 is a diagram for explaining a problem relating to document illumination in the image reading apparatus.
  • FIG. 3 is a diagram for explaining another problem relating to illumination of a document in the image reading apparatus.
  • FIG. 4 is a diagram illustrating a light source composed of a plurality of LEDs and illumination by the light source.
  • FIG. 5 is a diagram for explaining an example of an illumination method and an illumination device according to the first embodiment of the present invention.
  • FIG. 6 is a diagram illustrating an example of an image reading apparatus according to a second embodiment of the present invention.
  • FIG. 7 is a diagram illustrating an example of an image reading apparatus according to a third embodiment of the present invention.
  • FIG. 8 is a diagram for explaining a modification of the image reading apparatus according to the third embodiment of the present invention.
  • FIG. 9 is a diagram illustrating a means for converting a light beam diffusing from an LED into parallel light using a rotating parabolic mirror.
  • FIG. 10 is a diagram for explaining means for converting a light beam diffused from an LED into parallel light using a convex lens.
  • FIG. 11 is a diagram for explaining one example of a lighting device according to a fourth embodiment of the present invention.
  • FIG. 12 is a diagram for explaining another example of a lighting device according to the fourth embodiment of the present invention.
  • FIG. 13 is a diagram for explaining one example of an illumination device and an image reading device according to a fourth embodiment of the present invention.
  • FIG. 14 is a diagram for explaining another example of the illumination device and the image reading device according to the fourth embodiment of the present invention.
  • FIG. 16 is a diagram illustrating an example of an illumination method and an image reading apparatus according to a sixth embodiment of the present invention.
  • FIG. 19 is a diagram illustrating an example of a lighting device according to an eighth embodiment of the present invention.
  • FIG. 20 is a diagram illustrating an example of an image reading apparatus according to a ninth embodiment of the present invention.
  • FIG. 21 is a diagram illustrating an example of an image reading apparatus according to a tenth embodiment of the present invention.
  • FIG. 22 is a diagram for explaining the relationship between the illuminance distribution in the imaging region and the relative brightness of the reduction optical system on the CCD in the image reading apparatus using the reduction optical system.
  • FIG. 23 is a diagram for explaining a method of determining the arrangement intervals of a plurality of light sources that illuminate an imaging region so that the relative brightness of an image formed on a two-dimensional CCD is constant.
  • FIG. 24 is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate an imaging target region so that the relative brightness of an image formed on a two-dimensional CCD is constant.
  • FIG.25 A specific example of the relative brightness of an image that is imaged on a one-dimensional CCD by an imaging lens in an imaging target area illuminated at a constant illuminance, and the phase of the image that is imaged on the one-dimensional CCD. It is a figure which shows the specific example of target illuminance distribution (request
  • FIG. 26 A diagram showing a result of simulation toward a target relative illuminance for illuminating an illumination target area (imaging target area).
  • imaging target area It is a conceptual diagram for realizing an illumination device that matches the illuminance distribution of the light that illuminates the imaging region with the 1 / cos 4 ⁇ characteristic by adjusting the interval between the plurality of light sources.
  • FIG. 28] is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate an imaging target region so that the relative brightness of an image formed on a two-dimensional CCD is constant.
  • FIG. 29 is a diagram showing a simulation result of relative illuminance in the twelfth practical example of the present invention.
  • Fig. 31 is a diagram for explaining an example of a method for changing the radiation characteristics of the light that is also emitted by the light source.
  • Gaku 32] illuminates the imaging area so that the relative illuminance of the image formed on the three-dimensional CCD is constant. It is a figure explaining another example of arrangement
  • FIG. 35 is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate an imaging target region so that the relative brightness of an image formed on a three-dimensional CCD is constant.
  • the illuminance distribution of the light that illuminates the imaging area is adjusted to 1 / cos 4 ⁇ both by adjusting the power of each of the multiple light sources, adjusting the distance to the imaging area, and adjusting the radiation characteristics of the light emitted by the multiple light source forces. It is a conceptual diagram for implement
  • FIG. 38 is a diagram showing a simulation result on the difference between the relative illuminance and the target illuminance distribution in the sixteenth actual example of the invention.
  • FIG.39 By adjusting the angle of the illumination optical axis of light that is also emitted from multiple light sources, an illuminator that matches the illuminance distribution of the light that illuminates the imaging area with the 1 / cos 4 ⁇ characteristic is realized. It is a conceptual diagram for.
  • FIG. 40 is a diagram for explaining the formation of a virtual light source from a light source using a concave cylinder lens.
  • FIG. 41 is a diagram for explaining an optical component that can be used in the embodiments and examples of the present invention.
  • FIG. 42 is a diagram illustrating an optical component that can be used in the embodiment and examples of the present invention.
  • Electrode 22 ... Lead wire 23 ... Transparent resin 24 ... Food lens 25 ... Base 31 ... Photoreceptor, 32 ... Paper feed roller, 33 ... Sheet original, Sx ... Main scanning direction, Sy ... Sub-operation direction, ⁇ ... Illumination optical axis, AxR ... Reading optical axis, Ai ... Imaging area, Illumination area, Illumination target area, Di ... Illuminance distribution VI ⁇ ⁇ ⁇ longitudinally, Vs ... lateral direction, VLS ... virtual source, the virtual light source.
  • Embodiments of the present invention relate to a document surface illumination method, a (document) illumination device, and an image reading device using the same.
  • Embodiments of the present invention include, for example, an illumination method and an illumination device for illuminating a document surface of a copying machine or a facsimile, a solid-state imaging device mounted on a digital PPC (common paper copying machine), etc.
  • the present invention relates to an image reading apparatus (such as a film scanner and a non-day scanner) equipped with an imaging lens and an illumination device, and an illumination device for the image reading device.
  • scattered light from a document surface illuminated by light from a light source is imaged on a photoconductor or an image sensor by an imaging lens to form an image on an image on the document surface.
  • a one-dimensional image is formed at the target position, and the image formation target position on the document surface is sequentially moved in a direction (sub-scanning direction) perpendicular to the direction along the one-dimensional image (main scanning direction).
  • a document surface illumination method for an image forming apparatus that forms a two-dimensional image of a surface image
  • a plurality of light sources are arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction). Illuminating the document surface for an image forming apparatus, wherein the light beam emitted from the light source is diffused in a direction along the one-dimensional image of the document surface in a range of at least twice the interval between adjacent light sources. Is the method.
  • the scattered light from the document surface illuminated by the light from the light source is imaged on the photosensitive member or the image sensor by the imaging lens, thereby forming an image on the image on the document surface.
  • a one-dimensional image is formed at the target position, and the image formation target position on the document surface is sequentially moved in a direction (sub-scanning direction) perpendicular to the direction along the one-dimensional image (main scanning direction).
  • a document surface illumination method for an image forming apparatus that forms a two-dimensional image of a surface image, a plurality of light sources are arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction).
  • an original surface illumination method for an image forming apparatus is schematically focusing.
  • the light emitting means, the imaging means for forming an image on the image pickup device from the scattered light from the original surface illuminated by the light generated from the light emitting means, and the image on the original surface are used.
  • an illumination device for an image reading apparatus that reads an image, the light emitted from a plurality of light emitting means and a plurality of light emitting means arranged at least in a direction corresponding to a direction along the one-dimensional image (main scanning direction).
  • Light diffusion that diffuses the light flux in a direction along the one-dimensional image of the document surface in a range that is at least twice the interval between adjacent light-emitting means It is an illuminating device for image reading apparatuses characterized by having a means.
  • a pair of reflections is provided so as to sandwich a plurality of light emitting means arranged at least in a direction corresponding to a direction along the one-dimensional image (main scanning direction).
  • Mirrors are arranged in parallel.
  • the light diffusion means is a cylinder lens (or
  • the position of the light source in each of the plurality of light emitting units is arranged so as to correspond to each of the plurality of light emitting units.
  • an ellipsoidal mirror in which the position of the light source in each of the plurality of light emitting means is the position of one focal point corresponds to each of the plurality of light emitting means. Be placed.
  • a convex lens corresponding to each of the plurality of light emitting means is arranged.
  • At least a part of light beams emitted from a plurality of light sources are perpendicular to a direction along the one-dimensional image of the document surface (main scanning direction).
  • light focusing means for roughly focusing is arranged.
  • the light emitting means is a light emitting diode (LE).
  • the scattered light from the original surface illuminated by the light from the light source is imaged on the image sensor by the imaging lens, and the image reading position in the image on the original surface is obtained.
  • the light flux emitted from a plurality of light sources is diffused in a range along the one-dimensional image of the document surface in a range more than twice the interval between adjacent light sources, and To draft surface
  • An image reading apparatus having a plurality of lenses (illumination lenses) to be superimposed
  • the image reading apparatus for reading a two-dimensional image in the image on the document surface includes the illumination device according to the third embodiment of the present invention.
  • the scattered light from the original surface illuminated by the light from the light source is imaged on the image sensor by the imaging lens, and the image formation target position in the image on the original surface
  • the one-dimensional image is read and the image formation target position on the document surface is sequentially moved in the direction (sub-scanning direction) perpendicular to the direction of reading the one-dimensional image (main scanning direction) and the reading of the one-dimensional image is repeated.
  • the image reading apparatus that reads a two-dimensional image in the image on the document surface, a plurality of light sources arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction), and a plurality of light sources
  • the light beams emitted from a plurality of light sources are arranged so as to correspond to each other in a direction along the one-dimensional image of the document surface, and are diffused to a range that is equal to or larger than the interval between adjacent light sources.
  • the plurality of light sources has an illuminance distribution characteristic of light that illuminates the document surface at the document formation target position.
  • the image reading apparatus is arranged so as to be approximately opposite to a lightness distribution characteristic of an image formed on an imaging element by an imaging lens.
  • the interval between the plurality of light sources is set to be an image.
  • the distribution characteristic of the illuminance of the light that illuminates the document surface at the image formation target position is set so that it is roughly opposite to the lightness distribution characteristic of the image formed by the imaging lens on the imaging element.
  • an image reading apparatus according to a sixth embodiment of the present invention or a sixth embodiment of the present invention.
  • the distance from the document surface to the plurality of light sources is such that the distribution characteristic of the illuminance of the light that illuminates the document surface at the image formation target position is the image sensor. Is set so as to be approximately opposite to the brightness distribution characteristic of the image formed by the imaging lens.
  • a light flux emitted from a plurality of light sources The divergence angle is such that the illuminance distribution characteristic of the light that illuminates the original surface at the image formation target position is roughly opposite to the lightness distribution characteristic of the image formed by the imaging lens on the image sensor. To be set.
  • the directions of the optical axes of the plurality of light sources depend on the image forming pair.
  • the distribution characteristic of the illuminance of the light that illuminates the document surface on the document surface at the elephant position is set so as to be approximately opposite to the distribution characteristic of the brightness of the image formed on the image sensor by the imaging lens.
  • the “illuminating device for the image reading device” includes a plurality of light sources arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction) used in the image reading device. And an illuminating device that illuminates the document surface with light from these multiple light sources.
  • the interval between a plurality of light sources, the document surface Combination of at least two of force, distance to a plurality of light sources, divergence angle of light beams emitted from the plurality of light sources, and direction of optical axes of the plurality of light sources (for example, a plurality from the document surface)
  • the distance to the light source and the divergence angle of the luminous flux of the emitted light and the distribution characteristics of the illuminance of the light that illuminates the document surface at the image formation target position. May be set so as to be roughly opposite to the lightness distribution characteristic of the image formed by.
  • the irradiated surface is a surface having a certain area.
  • a plurality of light sources are arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction), and emitted from the plurality of light sources.
  • a wider area on the document surface using multiple light sources by diffusing the emitted light flux in the direction along the one-dimensional image of the document surface to a range that is at least twice the interval between adjacent light sources.
  • a light beam emitted from a plurality of light sources is divided into a direction (sub scan direction) perpendicular to the direction along the one-dimensional image of the document surface (main scanning direction).
  • a direction perpendicular to the direction along the one-dimensional image of the document surface (main scanning direction).
  • the reflecting mirror, the cylinder lens (or cylindrical lens), the parabolic mirror, the elliptical mirror, and the convex lens are plastic molded. Since it is possible to obtain the force S by means, the cost of the illumination device or the image reading device can be reduced.
  • the light source when a light emitting diode (LED) is used as a light source, the light source can be driven by a low-voltage DC power supply. Can be easily provided. As a result, the cost of the illumination device or the image reading device can be reduced.
  • LED light emitting diode
  • the plurality of light sources has an illuminance distribution characteristic of light that illuminates the document surface at the image forming target position so that the imaging element has an imaging lens. Since it is arranged so as to be roughly opposite to the brightness distribution characteristic of the image formed by the image, it is blocked or discarded without illuminating the original surface of the light emitted from the plurality of light sources. It is possible to reduce or eliminate the amount of light generated and to make the brightness distribution of the image formed by the imaging lens in the image sensor more uniform. As a result, it is possible to illuminate the document with higher efficiency with the light emitted from the light source, and it is possible to reduce the energy required to illuminate the document surface (energy saving).
  • the interval between the plurality of light sources is such that the distribution characteristic of the illuminance distribution of the light that illuminates the document surface on the document surface at the image formation target position is imaged. Since it is set so as to be roughly opposite to the lightness distribution characteristic of the image formed by the imaging lens on the element, it is blocked without illuminating the document surface among the light emitted from a plurality of light sources or It is possible to reduce or eliminate the amount of light thrown away and to make the illuminance distribution of the image formed by the imaging lens in the image sensor more uniform. As a result, it is possible to illuminate the document with higher efficiency by the light emitted from the light source, and it is possible to reduce the energy required to illuminate the document surface (energy saving).
  • the distance from the document surface to the plurality of light sources is the distribution characteristic of the illuminance of light that illuminates the document surface on the document surface at the image formation target position. Since it is set to be roughly opposite to the brightness distribution characteristics of the image formed by the imaging lens on the image sensor, the light emitted from multiple light sources is blocked without illuminating the document surface. It is possible to reduce or eliminate the amount of light emitted or discarded and to make the illuminance distribution of the image formed by the imaging lens in the image sensor more uniform. As a result, it is possible to illuminate the document with higher efficiency with the light emitted from the light source, and it is possible to reduce the energy required to illuminate the document surface (energy saving).
  • the divergence angle of light beams emitted from a plurality of light sources is the illuminance of light that illuminates the document surface at the image formation target position. Since the distribution characteristics are set so as to be roughly opposite to the distribution characteristics of the brightness of the image formed by the imaging lens on the image sensor, the original surface of the light emitted from the plurality of light sources is illuminated. It is possible to reduce or eliminate the amount of light that is interrupted or discarded without making it possible to make the illuminance distribution of the image formed by the imaging lens in the image sensor more uniform. As a result, it is possible to illuminate the document with higher efficiency by the light emitted from the light source. As a result, the energy required to illuminate the original surface can be reduced (energy saving).
  • the direction of the optical axis of the plurality of light sources is determined by the distribution characteristics of the illuminance of the light that illuminates the document surface at the image formation target position. Since it is set so as to be roughly opposite to the brightness distribution characteristic of the image formed on the element by the imaging lens, it is blocked without illuminating the document surface among the light emitted from the plurality of light sources or It is possible to reduce or eliminate the amount of light thrown away and to make the illuminance distribution of the image formed by the imaging lens in the image sensor more uniform. As a result, it is possible to illuminate the document with higher efficiency by the light emitted from the light source, and it is possible to reduce the energy required to illuminate the document surface (energy saving).
  • Set the illuminance distribution characteristics of the light that illuminates the document surface at the target position to be roughly opposite to the brightness distribution characteristics of the image formed by the imaging lens on the imaging element.
  • the amount of light that is blocked or discarded without illuminating the document surface among the light emitted from a plurality of light sources is reduced or eliminated, and the image formed by the imaging lens in the image sensor is reduced. Make the illumination distribution more uniform It can become. As a result, it is possible to illuminate the document with higher efficiency by the light emitted from the light source, and it is possible to reduce the energy required to illuminate the document surface (energy saving).
  • the illumination method and the illumination device according to the embodiment of the present invention are designed to form a latent image on a photoconductor by directly projecting an image on a document surface onto the photoconductor, and developing the latent image with black toner or color toner.
  • an illumination method and an illumination device used in an image reading apparatus generally called a digital printer or a scanner will be described. I will do it.
  • Example 1
  • FIG. 5 is a diagram for explaining an example of an illumination method and an illumination apparatus according to the first embodiment of the present invention.
  • FIG. 5 (a) is a top view of the example of the lighting device according to the first embodiment of the present invention
  • FIG. 5 (b) is a front view of the example of the lighting device according to the first embodiment of the present invention. is there.
  • FIG. 5 (c) shows the illuminance distribution in the main scanning direction (Sx) on the illumination target surface (imaging area) (Ai) obtained by the example of the illumination method according to the first embodiment of the present invention.
  • FIG. 5 (d) is a diagram showing the illuminance distribution in the sub-scanning direction on the illumination target surface (imaging area) (Ai) obtained by the example of the illumination method according to the first embodiment of the present invention. is there.
  • the illumination device according to the first embodiment of the present invention as shown in FIGS. 5 (a) and (b) is an illumination lamp and reflector in the conventional illumination device shown in FIGS. 1 (a) and (b). Corresponding to
  • the illumination device includes a plurality of LEDs (1), a plurality of rotary parabolic mirrors (2a), and an illumination lens. (3) It has a focusing lens (4a) and side mirror A (5a) and side mirror B (5b).
  • Each of the plurality of LEDs (1) is a light emitting diode chip and is used as a light source.
  • n LEDs (l) (Ll to Ln) are arranged at equal intervals in the main scanning direction (Sx).
  • Each of the plurality of rotating parabolic mirrors (2a) is arranged corresponding to the plurality of LEDs (1), and the light emitting surface of the LED (1) is located at the focal position of the rotating parabolic mirror (2a). By arranging the LED power, most of the diffused light is converted into parallel light.
  • the plurality of rotary paraboloid mirrors (2a) are used as a first focusing means for focusing the luminous flux diffusing at an angle of 180 ° from the light emitting surface of the LED (1) to the front side of the LED (1).
  • the illumination lens (3) is a cylinder lens array in the illumination device of the first embodiment of the present invention.
  • the illumination lens (3) diffuses the parallel light beam emitted from the rotary paraboloid mirror (2a) in the main scanning direction (Sx) and is diffused by the illumination lens (3).
  • the surface (Ai) (refers to the same part as the imaging region, but when the illumination device is described, the imaging region is referred to as an illumination target surface or an illumination target region) is illuminated.
  • the individual lenses constituting the cylinder lens array of the illumination lens (3) are completely or substantially the same cylinder lens.
  • f is the focal length of each cylinder lens
  • m is the width of each cylinder lens in the cylinder lens array direction (main scanning direction (Sx)).
  • each cylinder lens is equal to the interval between adjacent LEDs (l) in the plurality of LEDs (l).
  • illumination is performed by light transmitted through the cylinder lens in the cylinder lens arrangement direction (main scanning direction (Sx)).
  • the width m of each cylinder lens that is, the cylinder lens with respect to the interval between adjacent LEDs (1) in the plurality of LEDs (1).
  • the ratio (M / m) of the illumination range M on the illumination target surface (imaging area) (Ai) illuminated by the light that has passed through is more than twice.
  • the cylinder lens is equivalent to a plane parallel plate, and therefore, a paraboloid mirror.
  • the width of the cylinder lens array in the main scanning direction (Sx) may also be K.
  • the width of the cylinder lens in the main scanning direction (Sx) is preferably completely or substantially the same as the width of the paraboloid mirror (2a) in the main scanning direction (Sx). That is,
  • the force S is preferable, where n is the number of cylinder lenses constituting the cylinder lens array.
  • the focusing lens (4a) is a single cylinder lens that focuses the light transmitted through the illumination lens (3) onto the illumination target surface (imaging area) (Ai) in the sub-scanning direction (Sy). It is provided as follows. That is, the parallel light emitted from the rotating parabolic mirror (2a) is transmitted in the sub-scanning direction (Sy) In this case, the light is not diffused by the illumination lens (3), but is sharply focused on the illumination target surface (imaging area) (Ai) by the focusing lens (4). Since the focusing lens (4) is equivalent to a plane-parallel plate in the main scanning direction (Sx), the light diffused by the illumination lens (3) is not focused by the focusing lens (4). , Diffuse as it is. The collecting lens (4) can be easily substituted with a parabolic mirror having the same function as the focusing lens.
  • the focusing lens (4) transmits light transmitted through the illumination lens (3), which is not necessarily required, in the illumination device of the first embodiment of the present invention.
  • it may be applied to the illumination target surface (imaging area) (Ai) as parallel light.
  • the focusing lens (4) may be arranged on the illumination lens (3) side or on the illumination target surface (imaging region) (Ai) side position.
  • the focusing lens (4) can be formed integrally with the illumination lens (3). In this case, the number of parts used for the lighting device can be reduced by using plastic molding means.
  • the side mirror A (5a) and the side mirror B (5b) are mirrors arranged on both sides of the cylinder lens array of the illumination lens (3).
  • the side mirror A (5a) and the side mirror B (5b) are provided to irradiate the illumination target surface (imaging region) (Ai) with higher efficiency with the light emitted from the LED (l).
  • the light emitted from the three LEDs (l) (Ll, L2, and L3) is reflected by the side mirror A (5a) to the illumination target surface (imaging area) (Ai).
  • the light emitted from the three LEDs (1) (Ln-2, Ln-1 and Ln) is reflected by the side mirror B (5b) to the illumination target surface (imaging area) (Ai).
  • side mirror A (5a) and side mirror B (5 b) have their six LEDs (1) force as if they were also placed outside the lighting device. Since the light from the six LEDs (1) is reflected, the edge of the illumination target surface (imaging area) (Ai) is uniform as well as the center of the illumination target surface (imaging area) (Ai). Illuminance distribution is obtained. (Note that it is ideal to provide a side mirror to the illumination target surface (imaging area) (Ai) for the cylinder lens array force. In an actual image reading device, avoid contact glass as a document table.
  • the illuminance at the end of the illumination target surface (imaging area) (Ai) is slightly lower than the illuminance at the center of the illumination target surface (imaging area) (Ai). Accordingly, when the side mirror A (5a) and side mirror B (5b) are provided, it is necessary to increase the overall width of the illuminating device in the main scanning direction (Sx). The amount of variation in the overall width of the lighting device is very small compared to the amount of variation in the overall width of the lighting device when the side mirror is not used. )
  • the light emitted from (L4) is reflected by the rotating parabolic mirror (2a) corresponding to L4 and is emitted as substantially parallel light.
  • the light emitted from the rotary parabolic mirror (2a) corresponding to L4 is incident on the cylinder lens constituting the illumination lens (3) corresponding to L4.
  • the light that has passed through the cylinder lens is diffused regardless of the presence of the focusing lens (4) at a distance that exceeds the focal length f of the force cylinder lens that is once focused at the focal length f of the cylinder lens.
  • the width of the light beam emitted from the L4 of the LED (1) is equal to the width m of the cylinder lens, that is, the adjacent LEDs (1).
  • the ratio of the luminous flux width M on the illumination target surface (imaging area) (Ai) to the size of the LED (1) interval is more than twice. In Fig. 5, Q is about 6.5.
  • the illuminance distribution on the illumination target surface (imaging region) (Ai) due to only the light emitted from L4 of the LED (1) is as shown by the bold line in FIG. 5 (c). Things (Each-Di). That is, the illuminance on the axis (optical axis) passing through the center of the rotating paraboloid mirror (2a) corresponding to L4 and L4 of LED (1) is a peak, and from L4 as it goes away from the optical axis. The illuminance due to the emitted light decreases.
  • the illuminance distribution on the illumination target surface (imaging area) (Ai) due to only the light emitted from L4 of the LED (1) depends on the position on the illumination target surface (imaging area) (Ai).
  • the illuminance distribution on the illumination target surface (imaging area) (Ai) due to only the light emitted from L4 of the LED (1) depends on the position on the illumination target surface (imaging area) (Ai).
  • the light on the optical axis of L4 of LED (1) is the smaller amount of light emitted from L1 of LED (1), LED (1 ) L2 of light emitted from L2, and a larger amount of light emitted from L3 of LED (2).
  • the light on the optical axis of L4 of LED (1) is the same as the amount of light emitted from L3 of LED (l).
  • the amount of light emitted from L5 of LED (1), the amount of light emitted from L6 of LED (1), and the amount of light emitted from L2 of LED (1), and The amount of light emitted from L1 of LED (1) is included in the same amount as the amount of light emitted from L1 of LED (1).
  • the light emitted from L1 to L7 of LED (1) is superimposed on the illumination target surface (imaging area) (Ai) and Illuminate the illumination target surface (imaging area) (Ai).
  • an arbitrary point on the illumination target surface (imaging region) (Ai) is the number of numbers obtained by rounding down the numbers after the decimal point of the Q value described above.
  • the LED is illuminated with the light emitted from the LED (or 6 or 7 in Fig. 5) of the number obtained by rounding up the number after the decimal point of the LED or Q value described above.
  • the illuminance distribution on the illumination target surface (imaging region) (Ai) becomes more uniform and flat (shows the concept of “Total-Di”).
  • the light diffused from each of the plurality of LEDs (1) It is converted into almost parallel light by the rotating parabolic mirror (2a) corresponding to the LED (1), and passes through the illumination lens (3) as parallel light.
  • the illumination target surface (imaging area) (Ai) is illuminated as it is.
  • the illuminance distribution on the illumination target surface (imaging area) is the illuminance distribution due to the individual LEDs (1) as shown by the solid line in FIG.
  • the focusing lens (4a) when a sharp illumination distribution on the illumination target surface (imaging area) (Ai) is required in the sub-scanning direction (Sy), Use the focusing lens (4a).
  • the illumination device does not include the focusing lens (4a)
  • the illuminance distribution on the illumination target surface (imaging area) (Ai) in the sub-scanning direction (Sy) is shown by the two-dot chain line in FIG.
  • an intermediate illuminance distribution between a relatively sharp illuminance distribution and a relatively broad illuminance distribution is necessary on the illumination target surface (imaging area) (Ai).
  • the focal length of the focusing lens (4) is set so that the focal point of the focusing lens is away from the position of the illumination target surface (imaging area) (Ai).
  • An illuminance distribution having an arbitrary width can be obtained with (A i). In this way, the illuminance distribution on the illumination target surface (imaging region) (Ai) is maintained substantially constant in the main scanning direction (Sx), and the illumination target surface (imaging region) is observed in the secondary scanning direction (Sy).
  • the illuminance distribution on (Ai) can be arbitrarily set to a shear or broad illuminance distribution.
  • FIG. 6 is a diagram for explaining an example of an image reading apparatus according to the second embodiment of the present invention.
  • FIG. 6 (a) shows a second embodiment of the present invention using the lighting device according to the first embodiment of the present invention.
  • FIG. 6B is a front view of the image reading apparatus according to the second embodiment of the present invention using the illumination apparatus according to the first embodiment of the present invention.
  • FIG. 6 (a) a turning mirror (12) is depicted in addition to the illumination device according to the first embodiment of the present invention as shown in FIG.
  • FIG. 6 (b) when an illuminating device that does not bend the optical axis of the illuminating device is disposed, the optical axis of the reading system that is the optical path of the reflected light from the imaging region (Ai)
  • the entire optical axis of the illuminating device is tilted from the reading optical axis (A xR). is there.
  • the illumination optical axis (Axl) can be bent using the folding mirror (6). In this way, the size of the image reading device in the direction perpendicular to the contact glass (13) can be reduced by arranging the illumination device in parallel to the surface of the contact glass (13). .
  • the illumination device may or may not include the focusing lens (4a) depending on the target illuminance distribution in the imaging region (Ai) in the sub-scanning direction (Sy).
  • FIG. 6 (c) is a top view of the image reading apparatus according to the second embodiment of the present invention using a modification of the illumination apparatus according to the first embodiment of the present invention
  • FIG. FIG. 7 is a front view of an image reading apparatus according to a second embodiment of the present invention using a modification of the illumination apparatus according to the first embodiment of the present invention.
  • the focusing mirror (4b) is a parabolic mirror having a focal point in the imaging area (Ai) in the sub-scanning direction (Sy), and a reflection having no focusing function in the main scanning direction (Sx). It is a mirror that is a surface. Further, since the focusing mirror (4b) can have the function of the folding mirror (12) shown in FIGS. 6 (a) and 6 (b), the number of components of the lighting device can be reduced and the contact glass (13 It is possible to reduce the size of the image reading device in the direction perpendicular to). Note that the bending direction of the reading optical axis (AxR) may be any of the left and right directions in FIG.
  • the lighting device is designed so that the luminous fluxes emitted from 10 or more LEDs overlap, the illuminance unevenness in the entire imaging area (Ai) in the main scanning direction (Sx) can be reduced. It can be reduced to less than 10%.
  • electrically correcting the illuminance unevenness in the imaging area (Ai) it is possible to reduce the noise of the image signal even in a place where the illuminance is low in the imaging area (Ai), thereby improving the quality of the image signal. It becomes possible.
  • FIG. 7 is a diagram for explaining an example of an image reading apparatus according to the third embodiment of the present invention. Fig 7
  • the folding mirror B (6b) on the front side of the optical axis (AxR) Reflected to the imaging area (Ai) by the folding mirror B (6b) on the front side of the optical axis (AxR) (Note that the light beam on the direction mirror (12) side of the illumination optical axis (Axl) is read light. Since it folds in front of the axis (AxR), the size of the folding mirror A (6a) can be reduced, and the entire illuminator should be closer to the reading optical axis (AxR) side. I can do it. ).
  • the focal length of the focusing lens (4a) is common to all the light beams transmitted through the focusing lens (4a), the arrangement of the folding mirrors A and B (6a, 6b) is determined by the focusing lens (4a).
  • the light is reflected to the imaging region (Ai) by the folding mirror A (6a). Furthermore, the light flux on the contact glass (13) side of the illumination optical axis (Axl) is focused on the rear side (FB) of the imaging area (Ai), and the direction of the mirror is changed more than the illumination optical axis (Axl) (12 ) Side beam is focused on the front side (FA) of the imaging area (Ai). In this case, the central part of the document surface of the book document is irradiated with the light flux on the contact glass (13) side from the illumination optical axis (Axl), and the deflecting mirror (12) from the illumination optical axis (Axl).
  • the light beam on the side can be diffused without being focused on the original surface of the book original, and can be irradiated onto the book original. As a result, it is possible to irradiate the central portion of the book document with a good balance of light and to prevent or reduce reading of the central portion of the book document as a black image.
  • the light beam on the (12) side is reflected to the imaging area (Ai) by the focusing mirror A (4bl) on the rear side of the reading optical axis (AxR).
  • the focusing mirror A (4bl) and the focusing mirror B (4b 2) are parallel planes in the main scanning direction, and appear to be paraboloids having a focal point in the imaging region (A i) in the sub-scanning direction. It is a mirror.
  • the size of the focusing mirror A (4bl) is reduced because there is no need to reflect the light beam on the direction of the mirror (12) with respect to the illumination optical axis (Axl) by the focusing mirror A (4bl).
  • the power to do S In Fig.
  • both the luminous flux on the contact glass (13) side from the illumination optical axis (Axl) and the luminous flux on the deflecting mirror (12) side from the illumination optical axis (Axl) are both captured in the imaging region (Ai).
  • focusing is performed before and after the imaging area (Ai) independently.
  • the illuminance distribution in the imaging region (Ai) by the substantially parallel light beam on the contact glass (13) side from the illumination optical axis (Axl) shows a broad distribution
  • the illuminance distribution in the imaging area (Ai) due to the light flux on the direction of the deflecting mirror (12) with respect to the optical axis (Axl) shows a sharp distribution.
  • the example of the image reading apparatus as shown in FIGS. 7E and 7F is an example of an image reading apparatus that uses neither a focusing lens nor a focusing mirror.
  • the light beam on the contact glass (13) side from the illumination optical axis (Axl) out of the substantially parallel light beam transmitted through the illumination lens is read light.
  • Reflected to the imaging area (Ai) behind the axis (AxR), and the luminous flux on the deflecting mirror (12) side from the illumination optical axis (Axl) is reflected to the imaging area (AxR) before the reading optical axis (AxR). Reflect to Ai).
  • the illumination light out of the substantially parallel light beams transmitted through the illumination lens.
  • the light beam on the contact glass (13) side of the axis (Axl) is reflected to the imaging area (Ai) on the front side of the reading optical axis (AxR), and the deflecting mirror (12) side of the illumination optical axis (Axl) side Are reflected to the imaging area (Ai) behind the reading optical axis (AxR).
  • the image reading apparatus using the focusing lens or the focusing mirror the light use efficiency of the illuminating device is reduced, but the illuminance distribution in the imaging area (Ai) is broad, and the book document Reading the central portion as a black image can be prevented or reduced more effectively.
  • FIG. 7 shows an example of the arrangement of the focusing lens, the folding mirror, and the focusing mirror in the image reading apparatus.
  • the arrangement of the focusing lens, the folding mirror, and the focusing mirror is arbitrary, and is shown in FIG. It is not limited to that.
  • the light beam is divided in half before and after the illumination optical axis (Axl).
  • the ratio of the light beam division is not limited to 5: 5, and imaging is performed. It is arbitrarily set according to the degree of focusing in the area (Ai) or the type of document, and may be 6: 4 or 3: 7, for example.
  • FIG. 8 is a diagram for explaining a modification of the image reading apparatus according to the third embodiment of the present invention.
  • FIG. 8 (a) is a diagram for explaining a first modification of the image reading apparatus according to the third embodiment of the present invention
  • FIG. 8 (b) is an image according to the third embodiment of the present invention.
  • FIG. 10 is a diagram illustrating a second modification of the reading device.
  • the illuminating device main body is arranged on the front side or the rear side with respect to the reading optical axis (AxR) to illuminate the imaging region (Ai).
  • the light flux is divided into two and the imaging area (Ai) is illuminated from both the front side and the rear side of the reading optical axis (AxR).
  • two illumination device bodies are arranged on both the front side and the rear side of the reading optical axis (AxR), and the two illumination device bodies are arranged.
  • the imaging area (Ai) is used to illuminate the imaging area (Ai) from both the front and rear forces of the reading optical axis (AxR).
  • the two light source bodies (Axl) including the focusing lens (4a) are not bent and the two optical axes (Axl) are not bent.
  • the main body of the illuminating device is arranged obliquely with respect to the reading optical axis (AxR). In this case, it is possible to reduce the size of the image reading device in the direction parallel to the surface of the contact glass (13). As shown by the two-dot difference line in Fig.
  • the illuminating device body is placed parallel to the surface of the contact glass (13) using the folding mirror (6). You can also place yourself. In this case, the size of the image reading device in the direction perpendicular to the surface of the contact glass (13) can be reduced.
  • the example of the image reading apparatus as shown in FIG. 8 may not include either one of the two illuminating device bodies or both the force focusing lens and the focusing mirror. Modifications in the example of the image reading apparatus as shown can be applied.
  • FIG. 9 is a diagram for explaining a means for converting a light beam diffusing from an LED into parallel light using a rotary parabolic mirror.
  • Figure 9 (a) is a front view of a light source including LEDs and a rotating parabolic mirror.
  • FIG. 9 (b) is a side view of a light source including an LED and a rotating parabolic mirror.
  • the X, y, and z axes are defined, and the LED is at the intersection of the x, y, and z axes.
  • the center of the light emitting surface of (1) is arranged.
  • the focal length of the parabolic mirror (2a) is f
  • the paraboloid of the parabolic mirror (2a) is the paraboloid of the parabolic mirror (2a)
  • [0117] is a paraboloid obtained by rotating the parabola represented by X around the X axis.
  • the center of the light emitting surface of the LED (1) is arranged at the focal position (Pf) of the paraboloid.
  • the light emitting surface of the LED (1) faces the rotary parabolic mirror (2a).
  • the LED (l) is connected to the two electrodes (21) via the lead wire (22) and embedded in the transparent resin (23). .
  • the outer periphery of the rotating parabolic mirror (2a) may be circular, but radiation from the light emitting surface of LED (1) in Fig. 9 (a).
  • the intensity of the rotating paraboloid mirror (2a) in the vicinity is lower than that in the vicinity of the X axis, so the main scanning direction (Sx) (eg, z direction) Increased density to place a rotating paraboloid (2a) in
  • the peripheral part of the rotating parabolic mirror (2a) in the main scanning direction (Sx) may be cut off (that is, when the rotating parabolic mirror (2a) is viewed from the side, the rotating parabolic mirror is (2a) has an oval shape).
  • the peripheral part of the rotary parabolic mirror (2a) in the sub-scanning direction (Sy) is You can cut it out! / (Ie, when the paraboloid mirror (2a) is viewed from the side, the paraboloid mirror (2a) has a square shape).
  • the light emitting surface of LED (1) has an area, so there is only one place where light is emitted at the focal position of the rotating paraboloid. All light emitted at other positions is from the focal position of the rotating paraboloid. It is off.
  • the light emission vectors emitted from the focal position of the rotary parabolic mirror (2a) are all parallel light.
  • the light emission vectors emitted from other locations are all reflected when reflected by the rotary parabolic mirror (2a). It will deviate from the parallel light. The deviation increases as the distance from the focal point of the parabolic mirror (2a) increases.
  • Fig. 9 (c) shows the light emitted from a light source including a rotating paraboloid mirror and LED as shown in Figs. 9 (a) and 9 (b) at a certain distance. It is a light distribution characteristic figure which shows the vector intensity of the light which passes a certain point of the vicinity of an axis
  • the horizontal axis in Fig. 9 (c) represents the angle (°) from the optical axis of the parabolic mirror, and the vertical axis in Fig. 9 (c) represents the strongest value of the intensity of the light vector passing through a certain point.
  • the component parallel to the optical axis (X-axis) of the parabolic mirror (X axis) is strongest (0 degree), but there is also a component with an angle. (The amount decreases as the angle increases. The angle that falls to 50% is called the half-width, and in this example is ⁇ 5 degrees.)
  • FIG. 10 is a diagram illustrating a means for converting a light beam diffusing from an LED into parallel light using a convex lens.
  • 10 (a) is a front view of a light source including an LED and a convex lens
  • FIG. 10 (b) is a side view of the light source including an LED and a convex lens.
  • the light source including the LED and the convex lens shown in Figs. 10 (a) and 10 (b) is called a cannonball type, and the LED (1) attached to the base 25 is a convex lens made of a resin material. It is covered with a hood lens (24) with a shape.
  • LED (l) is connected to the electrode (21) via the lead wire (22).
  • the center of the light emitting surface of the LED (1) is arranged at the focal position (Pf) of the hood lens (24) which is a convex lens.
  • the lens size of the hood lens (24) As shown in Fig. 10 (a), the angular force of light incident on the periphery of the convex lens shape is determined to be less than the critical angle ⁇ .
  • the outer periphery of the hood lens (24) may be circular, but the radiation vector from the light emitting surface of LED (1) in Fig. 10 ( As shown in the distribution of Vr), since the intensity of light passing through the peripheral portion of the hood lens (24) is low, the density at which the hood lens (24) is arranged in the main scanning direction (Sx) (for example, z direction) In order to increase the image, the peripheral portion of the hood lens (24) in the main scanning direction (Sx) may be cut off (that is, when the hood lens (24) is viewed from the side, the hood lens (24) Oval shape).
  • the peripheral portion of the hood lens (24) in the sub-scanning direction (Sy) (for example, y direction) is cut off. (Ie, when the hood lens (24) is viewed from the side, the hood lens (24) has a square shape).
  • the entire side surface of the hood lens (24) is preferably a mirror surface.
  • the light incident on the side surface of the hood lens (24) is reflected by the mirror surface to reflect the light incident on the side surface of the hood lens (24) from the lens surface of the hood lens (24).
  • the side surface of the hood lens (24) in the main scanning direction (Sx) may be a non-mirror surface. In the main scanning direction (Sx) (z direction), light that escapes from the side surface of the hood lens can be used effectively by being incident on the adjacent hood lens.
  • the light source including the LED and the rotating paraboloid mirror in the illumination device illustrated in FIGS. 5 to 9 may be replaced with the light source including the LED and the convex lens as illustrated in FIGS. 10 (a) and (b). Good. Further, in the light source as shown in FIG. 10, it is also possible to arrange the convex lens corresponding to the hood lens (24) independently while keeping the tip of the hood flat.
  • the paraboloid as the first focusing means used in the first to third embodiments of the present invention in order to focus the light diffusing from the LED onto the surface to be illuminated (imaging area), the paraboloid as the first focusing means used in the first to third embodiments of the present invention.
  • a spheroidal mirror having a rotation axis coaxial with the rotation axis of the mirror can also be used.
  • the LED light emitting surface is arranged at one of the focal points of the spheroid mirror (for example, the first focus F1) and the focus of the spheroid mirror is used.
  • the second focusing means can be omitted. That is, the spheroid mirror can have both the function of the first focusing means and the function of the second focusing means used in the first to third embodiments of the present invention.
  • FIG. 11 is a view for explaining one example of a lighting device according to the fourth embodiment of the present invention.
  • FIG. 11 (a) is a front view of one example of a lighting device according to the fourth embodiment of the present invention
  • FIG. 1 Kb) shows the fourth embodiment of the present invention in the sub-scanning direction (Sy). It is a figure which shows the illumination intensity distribution given by one example of the illuminating device by.
  • a light source including an LED (1) and a spheroidal mirror (2b) is used, and the center of the light emitting surface of the LED (l) is rotated. It is located at the first focal point F1 of the ellipsoidal mirror (2b).
  • the illumination target surface (imaging region) (Ai) is disposed at the second focal point F2 of the spheroid mirror (2b). The light emitted from the LED (1) is reflected by the spheroid mirror (2b) and enters the illumination lens (3).
  • the light reflected by the spheroid mirror (2b) is diffused by the illumination lens (3) in the main scanning direction (Sx), while it passes through the illumination lens (3) as it is in the sub-scanning direction (Sy). Passes and converges to the position of the second focal point on the illumination target surface (imaging area) (Ai).
  • the illuminance distribution (Each—Di) (Total—Di) on the illumination target surface (imaging area) (Ai) in the sub-scanning direction (Sy) is ) Is the same as the illuminance distribution indicated by the two-dot chain line.
  • FIG. 12 is a diagram for explaining another example of the lighting apparatus according to the fourth embodiment of the present invention.
  • FIG. 12 (a) is a front view of another example of the lighting device according to the fourth embodiment of the present invention
  • FIG. b) is a diagram showing the illuminance distribution given by another example of the illumination device according to the fourth embodiment of the present invention in the sub-scanning direction (Sy).
  • the light diffused from the LED (1) is illuminated by changing the focal position of the convex lens (hood lens) (2c) shown in Fig. 10. Focus on the target surface (imaging area) (Ai)!
  • a light source including an LED (l) and a convex lens (2c) is used, and the focal length f of the convex lens (2c) is
  • a is the distance from the light emitting surface of the LED to the principal point of the convex lens (2c)
  • b is the distance from the convex lens (2c) to the illumination target surface (imaging area) (Ai).
  • the light emitted from the LED (1) is focused by the convex lens (2c) and enters the illumination lens (3).
  • the light focused by the convex lens (2c) is diffused by the illumination lens (3) in the main scanning direction, while passing through the illumination lens (3) as it is in the sub-scanning direction (Sy). Focus on surface (imaging area) (Ai).
  • the illuminance distribution (Each-Di) (Total-Di) on the illumination target surface (imaging area) (Ai) in the sub-scanning direction (Sy) is This is the same as the illuminance distribution shown by the two-dot chain line in d).
  • FIGS. 11 and 12 can be applied to the examples of the illumination device or the image reading device shown in FIGS.
  • FIG. 13 is a diagram for explaining one example of an illumination device and an image reading device according to the fourth embodiment of the present invention.
  • FIG. 13 (a) is a diagram showing an example of an illumination device according to the fourth embodiment of the present invention
  • FIG. 13 (b) is a diagram of one of the image reading devices according to the fourth embodiment of the present invention. It is a figure which shows an example.
  • the example of the illumination device shown in FIG. 13 (a) is the same as the example of the illumination device shown in FIG. 13 (a).
  • FIG. 13 (a) in addition to the illumination device, a turning mirror (12) of the image reading device is depicted.
  • FIG. 13 (b) shows an example of an image reading device in which the same lighting device as the example of the lighting device shown in FIG. 11 is mounted on the first traveling body (11).
  • the illumination device shown in Fig. 13 (a) is tilted with respect to the reading optical axis (AxR) without bending the illumination optical axis (Axl).
  • the lighting device may be arranged parallel to the surface of the contact glass (13). In this case, the size of the image reading device in the direction perpendicular to the surface of the contact glass (13) can be reduced.
  • FIG. 14 is a diagram for explaining another example of the illumination device and the image reading device according to the fourth embodiment of the present invention.
  • FIG. 14 (a) is a diagram showing another example of an illuminating device according to the fourth embodiment of the present invention
  • FIG. 14 (b) shows another example of the image reading device according to the fourth embodiment of the present invention.
  • FIG. 14 (a) is a diagram showing another example of an illuminating device according to the fourth embodiment of the present invention
  • FIG. 14 (b) shows another example of the image reading device according to the fourth embodiment of the present invention.
  • the turning mirror (12) of the image reading device is drawn in addition to the illumination device.
  • FIG. 14 (b) shows an example of an image reading device in which a lighting device similar to the example of the lighting device shown in FIG. 12 is mounted on the first traveling body (11).
  • the illumination device shown in FIG. 14 (a) is tilted with respect to the reading optical axis (AxR) without bending the illumination optical axis (Axl).
  • the illumination optical axis (Axl) of the illumination device shown in FIG. 14 (a) is bent by the folding mirror (6), so that The lighting device may be arranged parallel to the surface of the contact glass (13). In this case, the size of the image reading device in the direction perpendicular to the surface of the contact glass (13) can be reduced.
  • the light flux is divided before and after the reading optical axis (AxR), and before and after the reading optical axis (AxR). In both cases, the imaging region (Ai) can be illuminated using the divided light flux.
  • an LED that generates light of any one of the three primary colors of blue (B), green (G), and red (R) can be used. Or white
  • LEDs can also be used. However, it is preferable to use a green LED because green is almost representative of human visibility.
  • RGB LEDs blue (B), green (G), and red (red) are connected to the illumination device and image reading device shown in FIGS. R) LEDs may be arranged in combination or alternately, and a color one-dimensional image sensor may be used.
  • blue LEDs are arranged as LEDs L1, L4, L7 ''-, and green LEDs are used as LEDs L2, L5, L8.
  • red LED Arrange and arrange red LED as L3, L6, L9 '... of LED.
  • the number of LEDs that contribute to the illuminance distribution on the illumination target surface (imaging area) is reduced to one-third compared to the case of a single color (for example, 6 times in FIG. 5). Therefore, the characteristics of the illuminance distribution due to the light of each color on the illumination target surface (imaging area) will deteriorate. Therefore, if the gain Q is increased approximately 3 times by shortening the focal length f of the illumination lens and / or increasing the distance g from the illumination lens to the illumination target surface (imaging area), a single color is obtained. An illuminance distribution that is as good as the illuminance distribution in the case of using an LED can be obtained.
  • FIG. 15 is a diagram for explaining an example of the illumination method and illumination apparatus according to the fifth embodiment of the present invention.
  • FIG. 15 (a) is a top view of an example of a lighting device according to the fifth embodiment of the present invention
  • FIG. 15 (b) is a front view of an example of the lighting device according to the fifth embodiment of the present invention. is there.
  • FIG. 5 (c) shows the illuminance distribution (Each— in the main scanning direction (Sx) on the illumination target surface (imaging region) (Ai) obtained by the illumination method example according to the fifth embodiment of the present invention. Di) (Total—Di), and
  • FIG. 5 (d) shows the illumination target surface (imaging area) (Ai) obtained by the example of the illumination method according to the fifth embodiment of the present invention. It is a figure which shows the illumination intensity distribution of the subscanning direction (Sy) of Yes
  • the hood lens of the convex lens (2c) is attached to the red (R), green (G), and blue (B) three-color LED chips (1).
  • This is an example of a color lighting device including a light source.
  • a light source including an LED chip (1) and a convex lens (2c) is used instead of the light source including the LED and the rotating parabolic mirror in the illuminating device shown in FIG.
  • one light source has three types of LED chips (1) for blue (B), green (G), and red (R) arranged in a row (in the main scanning direction in FIG. 15) and arranged in a row.
  • the total power of the three types of LED chips (1) is covered with a hood lens that is a convex lens (2c).
  • the order of arrangement of the three-color LED chips (1) is not particularly limited.
  • the green (G) LED chip (1) is arranged in the center and the green (G) LED chip ( Adjacent to 1), a blue LED chip (1) and a red LED chip (1) are arranged.
  • the illumination target surface (imaging area) (Ai) caused by the single light source L k including the LED chip (1) of three colors (B, G, R) and the convex lens (2c) Illuminance distribution (Each—Di) (Total—Di) will be described.
  • the optical axis of the green luminous flux generated from the green (G) LED chip (1) coincides with the optical axis of the convex lens (2c).
  • the green luminous flux generated from the green (G) LED chip (1) behaves exactly the same as the luminous flux generated from the LED in Fig. 5.
  • the width of the cylinder lens constituting the illumination lens (3) that is, the width of the light source
  • the illumination target surface (imaging region) (Ai) is irradiated with a green light beam having a double width.
  • the Q length is 2 or more.
  • the optical axis of the red light flux generated from the red (R) LED chip (1) is slightly shifted from the optical axis of the convex lens (2c), the red (R) LED chip (1 ), The red light beam that passes through the convex lens (2c) and the green light generated from the green (G) LED chip (1).
  • the ratio of the width of the red luminous flux in the illumination target surface (imaging area) (Ai) to the width of the cylinder lens that constitutes the illumination lens (3), that is, the width of the light source Q is the green (G) LED chip ( This is the same as the value for the green luminous flux generated from 1).
  • the optical axis of the blue luminous flux generated from the blue (B) LED chip (1) is slightly shifted from the optical axis of the convex lens (2c), so the blue (B) LED chip (1)
  • the blue luminous flux generated from the lens passes through the convex lens (2c) and is slightly below the green light flux generated from the green (G) LED chip (1), and the illumination target surface (imaging area) ( Irradiate Ai).
  • the ratio of the width of the blue luminous flux in the illumination target surface (imaging area) (Ai) to the width of the cylinder lens that constitutes the illumination lens (3), that is, the width of the light source Q is the green (G) LED chip ( This is the same as the value for the green luminous flux generated from 1).
  • the colored luminous flux is indicated by a solid line, and the blue luminous flux is indicated by a thin broken line.
  • the concept of the illuminance distribution on the illumination target surface (imaging area) (Ai) for each of the three colors is shown as an individual illuminance distribution (Each Di) in Fig. 15 (c). Also, other light sources, L, L, L, L
  • the illuminance on the illumination target surface (imaging area) (Ai) on the optical axis of the light source also contributes to the illuminance of the luminous flux generated from the light source in the circumference k k of the light source.
  • the total illuminance distribution (Total—Di) due to the whole of these light sources is also shown in Fig. 15 (c).
  • the illumination device shown in Fig. 15 does not include the focusing lens (4a), the parallel luminous flux of each color that has passed through the illumination lens (3) remains as it is as the illumination target surface (imaging region) ( Ai) To do.
  • the illuminance distribution (Di) on the illumination target surface (imaging region) (Ai) in the sub-scanning direction (Sy) has a broad distribution as shown by the solid line in FIG.
  • the illumination device shown in FIG. 15 is provided between the illumination lens (3) and the illumination target surface (imaging region) (Ai) and is illuminated by the illumination target surface (imaging region) (Ai) force focal length F.
  • the focusing lens (4a) disposed at the position is included, the parallel luminous flux of each color that has passed through the illumination lens (3) is focused on the illumination target surface (image area) (Ai).
  • the illuminance distribution on the illumination target surface (imaging area) (Ai) in the sub-scanning direction (Sy) has a sharp distribution (Each_Di) (Total— Di).
  • the focal length f of the convex lens (2c) is set as follows. Similar to the example of the lighting device in FIG.
  • a is the distance from the light emitting surface of the LED chip (1) to the principal point of the convex lens (2c), and b is from the principal point of the convex lens (2c) to the illumination target surface (imaging area) (Ai). Is the distance. In this case, it is not necessary to provide the focusing lens (4a).
  • the illumination device as shown in FIG. 15 When the illumination device as shown in FIG. 15 is mounted on the first traveling body of the image reading device, the illumination device as shown in FIG. 15 is replaced with the image reading device as shown in FIGS. It can be applied to.
  • FIG. 16 is a view for explaining an example of the illumination method and the image reading apparatus according to the sixth embodiment of the present invention.
  • FIG. 16A is a top view of an example of the image reading apparatus according to the sixth embodiment of the present invention
  • FIG. 16B is a front view of the example of the image reading apparatus according to the sixth embodiment of the present invention. It is a figure.
  • FIG. 16 (c) is a diagram showing the illuminance distribution in the sub-scanning direction on the illumination target surface (imaging area) obtained by the example of the illumination method according to the sixth embodiment of the present invention.
  • An example of an image reading apparatus as shown in Fig. 16 is a hood lens with a convex lens (2c) in a batch of three red LED chips (1) of red (R), green (G), and blue (B). 1 is an example of a color image reading apparatus using a light source with a light attached.
  • the arrangement of the three-color LED chips (1) of the illumination system is such that the one-dimensional imaging element (15) of the reading system for reading the image of each color Can be associated with
  • the system on the left side of the illumination target surface (imaging region) (Ai) is the illumination system
  • the system on the right side of the illumination target surface (imaging region) (Ai) is the reading system. It is a system.
  • the imaging area (Ai) is illuminated using the illumination system, and the image of the original placed in the imaging area (Ai) is read by the reading system.
  • the reading system of the color image reading apparatus uses a three-line CCD in which three one-line CCDs (-dimensional imaging device (15)) are arranged in parallel. Each of the three 1-line CCDs is provided with a color filter (18) that transmits red (R), green (G), or blue (B). Read the color image that passes through the filter (18).
  • a three-line CCD equipped with such a power color filter (18) cannot simultaneously read images at the same location in the imaging area (Ai) of the document.
  • the size of the pixel constituting the 600 dpi image is 42.3 m.
  • the reading system of the current image reading device is a reduction optical system, and in the image sensor, the reading system is Corresponds to 10 ⁇ , 7 ii m, or 4 ⁇ 7 m, depending on the reduction ratio.
  • the three 1-line CCDs need to be separated from each other by a distance corresponding to 3 to 4 pixels.
  • the interval between the three 1-line CCDs is roughly equivalent to 0.4 to 0.2 mm in the image area (Ai) on the document surface.
  • red, green, and blue images are read at intervals of 0.4 to 0.2 mm in the imaging area (Ai) on the original surface. Therefore, the red, green, and blue light fluxes generated from the red, green, and blue LED chips (1) are irradiated at intervals of 0.4 to 0.2 mm in the imaging area (Ai) of the document surface. It is preferable.
  • MO is the distance between the LED chips (1) of each color
  • ml is the distance between the centers of the light fluxes of each color from the LED chips (1) of each color passing through the focusing lens (4a)
  • Fig. 16 (c) shows the illuminance distribution in the sub-scanning direction (Sy) of the image reading device shown in Figs. 16 (a) and 16 (b).
  • the arrangement of the colors R, G, B is assumed to be on a straight line in the main scanning direction (Sx) or the sub-scanning direction (Sy).
  • the arrangement of the colors S, R, G, B There is no particular limitation, and for example, the colors of R, G, and B may be arranged at the vertices of a triangle, the letter “K” in hiragana, or the letter “L” in English. In such a case, an optimum design of the illumination device and the image reading device can be achieved by combining the ideas as shown in FIGS.
  • FIG. 17 is a view for explaining one example of the illumination method and illumination apparatus according to the seventh embodiment of the present invention.
  • FIG. 17 (a) is a perspective view of an example of an illuminating device according to the seventh embodiment of the present invention
  • FIG. 17 (b) is an image reading device according to the seventh embodiment of the present invention.
  • FIG. 17 (c) is a side view of one example of an image reading apparatus according to the seventh embodiment of the present invention.
  • FIG. 17 (d) is a diagram showing the illuminance distribution in the main scanning direction on the illumination target surface (imaging region) obtained by one of the illumination methods according to the seventh embodiment of the present invention.
  • an example of an illumination device as shown in FIG. 17 is a rectangular light emitting surface in the main scanning direction (Sx) between a plurality of LEDs (1) having a rectangular light emitting surface and an illumination target area (Ai). Cylinder lens array illumination that diffuses the luminous flux generated by multiple LEDs (1) Includes lens (3). Then, between the plurality of LEDs (1) having a rectangular light emitting surface and the illumination lens (3), a plurality of LEDs (1) having a rectangular light emitting surface in the sub-scanning direction (Sy)!
  • a focusing lens (4a) for the cylinder lens that focuses the luminous flux generated from the lens is inserted.
  • the concept of setting the focal length of the illumination cylinder lens is the same as that in the first to sixth embodiments.
  • the focusing lens (4a) is shown to be focused as shown in FIG. 17 (c).
  • a plurality of LEDs (1) having a rectangular light emitting surface are used.
  • the generated light beam may be converted into parallel light or diffused light that is not necessarily focused.
  • the insertion of the focusing lens (4a) is not always essential.
  • each of the plurality of LEDs (1) having a rectangular light emitting surface in the main scanning direction (Sx) is provided.
  • the luminous flux generated by the force not only enters the cylinder lens of the illumination lens (3) corresponding to each LED (1), but also the cylinder lens of the illumination lens (3) corresponding to each LED (1). It also enters the cylinder lens in the vicinity (or adjacent to the cylinder lens).
  • the luminous flux generated by each of the plurality of LEDs (1) having a rectangular light emitting surface is further diffused by the illumination lens (3).
  • the light beam diffused from L4 of LED (1) is mainly incident on the cylinder lens corresponding to L4 of LED (1), and has a preset magnification. Then, the surface to be illuminated (imaging area) (Ai) is irradiated. However, a part of the light beam diffused from L4 of LED (l) also enters the cylinder lens corresponding to L3 and L5 of LED (1) adjacent to L4 of LED (1). In addition, a part of the light beam diffused from L4 of LED (1) is also incident on the cylinder lens corresponding to L2 and L6 of LED (l) located near L4 of LED (l). As a result, in the example of the illuminating device as shown in FIG. 17, it is possible to diffuse light S generated from the LED (1) more widely.
  • the main scanning direction (Sx)! Therefore, it is possible to significantly reduce fluctuations in the illuminance distribution on the illumination target surface (imaging area) (Ai) due to variations in the luminous efficiency of multiple LEDs (1). That is, in the conventional illumination device as shown in FIG. 4, in the main scanning direction (Sx), the illumination target surface illuminated by the LED (1) having lower luminous efficiency (imaging) The ratio of illuminance hi on the illumination target surface (imaging area) (Ai) illuminated by the LED (1) with higher luminous efficiency relative to the illuminance h2 in area (Ai) is approximately double.
  • the illuminating device as shown in FIG. 17 since the range of light beam diffusion in the main scanning direction (Sx) is wider, it is effective to provide side mirrors (5a, 5b) in the illuminating device. It is effective to install the side mirrors (5a, 5b) up to the side of LED (1). In this case, it is possible to irradiate the illumination target surface (imaging region) (Ai) with the diffused light from the LED without diffusing outside the illumination target region (Ai) in the main scanning direction (Sx). it can.
  • FIG. 18 is a diagram for explaining another example of a lighting device according to the seventh embodiment of the present invention.
  • FIG. 18 (a) is a top view of another example of an illuminating device according to the seventh embodiment of the present invention
  • FIG. 18 (b) is a diagram of another example of the image reading device according to the seventh embodiment of the present invention. It is a front view.
  • a parabolic mirror (2d) is used instead of the condenser lens (4a) in the example of the illumination device as shown in FIG. As shown in Fig. 17, LEDs with rectangular light-emitting surfaces are used side by side.
  • the parabolic mirror (2d) has a parallel plane cross section in the main travel direction (Sx) and a cross section of the paraboloid in the sub-scan direction (Sy)! Have
  • the illumination device as shown in FIG. 18, there is no barrier against the luminous flux generated by each of the plurality of LEDs (1) in the main scanning direction (Sx), so that as shown in FIG.
  • the luminous flux generated from each LED (1) not only enters the cylinder lens of the illumination lens (3) corresponding to each LED (1), but also each LED (1 It is also incident on the cylinder lens).
  • the luminous flux generated from each LED (1) is further diffused by the illumination lens (3).
  • L4 one of the LEDs (1)
  • the scattered light beam mainly enters the cylinder lens corresponding to L4 of the LED (1), and illuminates the illumination target surface (imaging area) (Ai) at a preset magnification.
  • the diffusion range of the light flux in the main scanning direction (Sx) is wider, it is effective to provide the side mirrors (5a, 5b) in the illuminating device. It is effective to provide the side mirrors (5a, 5b) up to the side of the parabolic mirror (2d). In this case, it is possible to irradiate the illumination target surface (imaging region) (Ai) without diffusing the diffused light from the LED outside the illumination target region (Ai) in the main scanning direction (Sx). it can.
  • the illumination device shown in FIG. 18 includes a focusing lens (4a), but the focusing lens (4a) is not necessarily an essential component.
  • a force S using a parabolic mirror (2a) is used as the first bundling means, and an ellipsoidal mirror is used as the first focusing means. it can.
  • the ellipsoidal mirror has a parallel plane section in the main scanning direction (Sx), and an ellipsoidal section in the sub-scanning direction (Sy).
  • the first focal point of the elliptical surface of the elliptical mirror is located at the center of the light emitting surface of the LED, and the second focal point of the elliptical surface of the elliptical mirror is located in the illumination target area (Ai).
  • the focusing lens (4a) becomes unnecessary.
  • an illumination device for a color image reading device using independent LEDs of three colors R, G, and B will be described.
  • the LEDs L ;! to L7 as shown in FIG. 17 are formed of one color LED and the other two color LEDs are added.
  • the other two colors (R and B) LEDs are arranged on both sides of the one color (G) LED in the sub-scanning direction (Sy). It is possible to provide a light source composed of colored LEDs.
  • FIG. 19 is a diagram for explaining an example of a lighting apparatus according to the eighth embodiment of the present invention.
  • FIG. 19 (a) is a top view of another example of an illuminating device according to the eighth embodiment of the present invention, and
  • FIG. 19 (b) shows another image reading device according to the eighth embodiment of the present invention. It is a front view of an example.
  • a cylinder lens array composed of a plurality of adjacent convex cylinder lenses has been shown as the illumination lens.
  • a cylinder lens array composed of a plurality of concave cylinder lenses arranged adjacent to each other can also be used.
  • a cylinder lens array composed of a plurality of adjacent concave cylinder lenses is used as the illumination lens (3). Even when a cylinder lens array composed of a plurality of contiguous concave cylinder lenses is used as the illumination lens (3), the luminous flux generated from the LED (1) is transmitted in the main scanning direction ( In Sx), it is possible to diffuse S.
  • the focal length force of each concave cylinder lens that constitutes the cylinder lens array, and the illumination target surface (imaging area) (Ai) from the principal point of the concave cylinder lens corresponding to one of the LEDs (1) If the distance force up to 3 ⁇ 4, the expansion factor Q of the width of the luminous flux of light emitted from one of the LEDs (1) in the main scanning direction (Sx) is
  • Q is 2 or more.
  • the reading system including the document table (container glass), the imaging lens, and the one-dimensional imaging device in the image reading device is fixed, while the first The traveling body and the second traveling body move differentially in the sub-scanning direction.
  • the illuminating device by the 1st-8th Example of this invention is mounted in a 1st traveling body. Except for the lighting device, the first traveling body is equipped only with a turning mirror that bends the optical path of the light reflected from the imaging region, so that the mass of the first traveling body does not increase and the first traveling body does not increase. Reading an image by moving the row body and the second traveling body is suitable for high-speed reading. However, if low-speed reading is permitted, it is conceivable that a reading device is also mounted on the first traveling body. In this case, since the second traveling body is unnecessary, only one traveling body may be provided. ).
  • FIG. 20 is a view for explaining an example of an image reading apparatus according to the ninth embodiment of the present invention.
  • FIG. 20 (a) is a diagram for explaining an example of an image reading apparatus according to the ninth embodiment of the present invention
  • FIG. 20 (b) is an illustration of the image reading apparatus according to the ninth embodiment of the present invention. It is a figure explaining another example.
  • the illumination unit (10) as the illuminating device according to the first to eighth embodiments of the present invention reads as a reading system. It is mounted on the traveling body (11a) together with the unit (16). Since the reading unit (16) is a reduction optical system including an imaging lens and an imaging element, a certain distance from the document surface to the imaging lens is required.
  • the image light reflected from the document surface is once redirected by the deflecting mirror (12) in the direction parallel to the contact glass (13). After being folded, the two folding mirrors (17a) and (17b) are each folded twice and guided to the reading unit (16).
  • the image light reflected from the document surface is folded back diagonally to the upper right by the turning mirror (12), and the first folding mirror ( After being changed in a direction parallel to the contact glass (13) by 17a), it is directed to the second folding mirror (17b).
  • the light incident on the second folding mirror (17b) is reflected again slightly downward and returned again to the first folding mirror (17a).
  • the light returned to the first folding mirror (17a) is reflected obliquely downward, further reflected by the third folding mirror (17c), and in a direction parallel to the surface of the contact glass (13), Guided to reading unit (11).
  • a reading system such as a reading unit (11) and an illumination unit.
  • any of the illumination devices according to the first to eighth embodiments of the invention is used as the illumination unit (10). Can it can.
  • the lighting device shown in Fig. 7 (e) is directly adopted.
  • a convex lens is used instead of the rotary parabolic mirror as the first focusing means in the image reading apparatus shown in FIG. 20 (a).
  • the illuminating device and the illuminating method for mounting on a reduction optical system or a digital image reading device that reads an image with an image sensor has been described.
  • the illumination apparatus and illumination method as shown in the first to ninth embodiments of the present invention can also be used as an illumination method for mounting in an equal magnification optical system or an analog copying machine.
  • FIG. 21 is a diagram for explaining an example of an image reading apparatus according to the tenth embodiment of the present invention.
  • An example of the image reading apparatus as shown in FIG. 21 is an image reading apparatus for an image forming apparatus that copies a sheet-like document.
  • the imaging lens (14) is a microlens array, and a number of aperture lenses are arranged so as to have the same length as the width of a sheet document (33) such as a length lens of the microlens array. It is a thing.
  • the imaging lens (14) is arranged between the imaging area (Ai) and the photoconductor (31) in order to provide an equal-magnification optical system.
  • the sheet document (33) is pressed and fed by the paper feed roller (32) in the imaging region (Ai) portion on the contact glass (13) with little friction with the sheet document (33).
  • the photoconductor (31) is moved in synchronization with the feeding of the sheet document (at the same speed). Note that illustration of peripheral devices of the photosensitive member such as a charging device and a transfer device for charging the photosensitive member (31) is omitted.
  • the illuminating apparatus is obtained by removing the traveling body and changing the position of the folding mirror in the illuminating apparatus shown in FIG. 7 (b).
  • the imaging area (Ai) of the sheet original (33) is illuminated one-dimensionally, and the image on the sheet original (33) is transferred to the photoconductor (14) via the imaging lens (14). 31) Projecting above.
  • the entire image on the sheet original (33) can be projected as a two-dimensional image on the photosensitive member (31). it can.
  • FIG. 22 shows the illuminance distribution in the imaging area (Ai) in the image reading apparatus using the reduction optical system.
  • FIG. 22 (a) is a diagram showing the arrangement of the imaging area (Ai), imaging lens, and one-dimensional CCD in an image reader using a reduction optical system.
  • Fig. 22 (b) shows (1) results. It is a figure explaining the relationship between the brightness distribution of the image imaged on one-dimensional CCD by an image lens, and the illuminance distribution (Di) requested
  • a one-dimensional CCD is placed parallel to the imaging area (Ai), and an imaging lens (14) is placed between them to form an image on the one-dimensional CCD.
  • an imaging lens (14) is placed between them to form an image on the one-dimensional CCD.
  • the imaging lens (14 ) when an image in the imaging region (Ai) is imaged on a one-dimensional CCD as a one-dimensional imaging device (15) by the imaging lens (14), the imaging lens (14 ), the imaging lens (14 ), the imaging lens (14 ), The brightness of the image on the periphery of the one-dimensional CCD is lower than the brightness of the image on the center of the one-dimensional CCD.
  • W is the length of the imaging region (Ai) in the main scanning direction (Sx), and the imaging lens (14) is moved in the vertical direction at the center of the imaging region (Ai). If the Ld is the distance from the imaging region (Ai) to the imaging lens (14), it is incident on the imaging lens (14) with respect to the optical axis of the imaging lens (14).
  • the maximum angle ⁇ of the ray angle ⁇ is
  • the relative value of the brightness of the image formed by the imaging lens (14) at each position in the main scanning direction (Sx) on the one-dimensional CCD is determined according to the so-called cosine fourth law. It changes with cos 4 ⁇ as shown in curve (1) of Fig. 22 (b) with respect to the angle ⁇ of the light ray incident on the imaging lens from the position in the imaging region (Ai) corresponding to.
  • the imaging lens (14) The brightness of the image on the one-dimensional CCD imaged by) is reduced by several tens of percent.
  • the amount of light incident on the one-dimensional CCD is converted into an electric signal by the one-dimensional CCD. Therefore, after converting the amount of light into an electric signal, the amplification factor of the electric signal is changed to form an image. It is possible to correct the difference in brightness of the image formed by the lens (14). However, in this case, since the dynamic range is reduced, noise increases around the one-dimensional CCD where the brightness of the image formed by the imaging lens (14) is relatively low. As a result, the image read by the one-dimensional CCD becomes dirty.
  • the optical axis of the imaging lens (14) is placed on the imaging region (Ai) side of the imaging lens (14) so as to be inversely proportional to the relationship shown by the curve (1) in Fig. 22 (b).
  • the power to insert a light shielding mask that increases the amount of light shielded from the position of the nearby imaging area (Ai), or the reflectance of the reflector that reflects light from the light source It is also possible to make the illuminance of the light imaged on the one-dimensional CCD constant by changing the reflectivity at the center of the LED to be low. In such a case, the correction of the electric signal can be reduced. However, it is not desirable from the viewpoint of energy saving to block or discard the light emitted from the light source.
  • the imaging region (Ai) is obtained so that the illuminance distribution (Di) required for the imaging region (Ai) shown in the curve (2) in Fig. 22 (b) without throwing away the luminous flux that also generates the light source power. ) Should be illuminated. Then, the utilization efficiency of the light emitted from the light source can be improved, and as a result, the energy S for reducing the energy of the light illuminating the imaging area (Ai) (achieving energy saving) can be reduced.
  • the interval between a plurality of light sources such as LEDs is used.
  • FIG. 23 is a diagram for explaining a method for determining the arrangement intervals of a plurality of light sources that illuminate the imaging target area (Ai) so that the relative brightness of the image formed on the one-dimensional CCD is constant. is there.
  • the arrangement interval of a plurality of light sources (for example, LEDs) that illuminate the imaging target area (Ai) is set at the center ( It narrows away from the imaging lens.
  • the arrangement shown in FIG. 22 (a) is shown rotated by 90 degrees counterclockwise. In the symbols shown there, the same symbols as those in FIG. 22 have the same meaning.
  • Wh is half the length W of the imaging target area (Ai) in the main scanning direction (Sx), and is calculated from the center of the imaging target area (Ai).
  • the sub-scanning direction (Sy) In order to calculate the interval between multiple light sources that illuminate the imaging target area (Ai) so that the relative brightness of the image formed on the one-dimensional CCD is constant, the sub-scanning direction (Sy) The design or simulation is based on the premise that the light source power and other luminous fluxes do not diverge. Specifically, in the sub-scanning direction (Sy), the imaging target area (Ai) is illuminated using light emitted from a plurality of light sources as parallel light, or light emitted from a plurality of light sources is to be imaged. Adopt either the force focused on the area (Ai), or somewhere in between.
  • the upper half region and the center line of FIG. 23 (the optical axis of the imaging lens) Since the lower half region is symmetrical, only the lower half region will be described for convenience of explanation.
  • the lower half area half of the imaging target area (Ai) in the main scanning direction (Sx)
  • the point on the center line is set as the origin.
  • the point number of the origin is set to 0, and the point numbers of each division point are numbered l to n in the order from the origin, and the interval from origin 0 to division point 1 is divided from division point 1.
  • the interval from point 2 to ..., and the interval from division point n—1 to end point n are represented by wl, w2,.
  • the interval between wl and wn is obtained so that the illuminance distribution (Di) required for the imaging target area (Ai) shown in the curve (2) in Fig. 22 (b) is obtained.
  • the N division of the area (half of the imaging target area (Ai) in the main scanning direction (Sx)) is initially divided into N equal parts. Then, assuming that the entire area to be imaged (Ai) is illuminated with a constant illuminance, the relative brightness of the position corresponding to each division point imaged on the one-dimensional CCD by the imaging lens is expressed by the cosine fourth law. So ask. Specifically, the relative brightness of the image formed on the one-dimensional CCD by the imaging lens corresponding to the kth division point on the imaging target area (Ai) is cos 4 ⁇ . Also this
  • ⁇ is the center of the imaging lens and the area to be imaged with respect to the optical axis of the imaging lens.
  • ⁇ is the angle of a straight line connecting the center of the imaging lens and the nth division point with respect to the optical axis of the imaging lens and coincides with ⁇ max.
  • the distance between the division points is given again by division in proportion to the relative brightness corresponding to each division point. That is, the intervals wl, w2, ...
  • the relative brightness of the image formed on the two-dimensional CCD is obtained by the cosine fourth law. Specifically, the relative brightness of the image formed on the one-dimensional CCD corresponding to the kth division point is co s 4 0 ′. The sum of the relative brightness is
  • FIG. 24 is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate the imaging target area (Ai) so that the relative brightness of an image formed on the one-dimensional CCD is constant.
  • FIG. 24 (a) is a diagram showing the arrangement of a plurality of light sources and the position of the mirror surface where the side mirrors are arranged
  • FIG. 24 (b) is a diagram showing an example of the radiation characteristics of the light sources.
  • FIG. 24 (a) is an enlarged view of a portion expressed on the left side of the imaging target surface (imaging target area) (Ai) in FIG.
  • the distance from the illumination target area (imaging target area) (Ai) by L0 and parallel to the imaging target area (Ai) was obtained in the above description.
  • a light source is placed at each obtained division point.
  • a mirror surface (side mirror) is placed at the position of the outside PM1, and the relative illuminance at each position of the imaging target area (Ai) is calculated.
  • This mirror surface reflects the luminous flux emitted from a plurality of light sources placed on the light source arrangement position corresponding to the point where the range of the imaging target area (Ai) is divided, and the light force is also on the extension line of the light source. Is The area of the illumination target area (Ai) is illuminated as if.
  • n + 1 light sources obtained by dividing half of the imaging target area (Ai) in the main scanning direction (Sx) by N are denoted by P 1, P 2, ⁇ ' ⁇ ⁇ and ⁇
  • the positions of the arranged light source images are ⁇ , ⁇ , ⁇ ' ⁇ ⁇ .
  • the distance between the light source located at ⁇ n + 1 n + 2 2n + ln and the image of that light source obtained by the side mirror located at P is obtained by deducting the above calculation method . Since the position P and the position P are in a mirror image relationship with the side mirror, the mirror surface of the side mirror is provided at a position half the distance between the position P and the position P. Furthermore, when the above calculation method is deduced and the interval between the position P and the position P, and the interval between the position P and the position P are obtained, the position P
  • the interval is wide because it is a virtual image with a mirror surface (naturally, the interval between position P and position P, ..., position P and
  • the distance from position P is the distance between position and position P, respectively.
  • a side mirror that is paired with the side mirror provided outside the nth light source is also provided in the upper half of the center line of the imaging target area (Ai) (the optical axis of the imaging lens). (Position of PM2)
  • the side mirrors provided outside the nth light source are arranged in parallel to each other. For this reason, the force S that generates an unlimited number of virtual light sources that are mirror images by the pair of side mirrors, of which the virtual light source that is generated by two or more reflections by the side mirrors is far from the imaging target area (Ai). Therefore, the contribution ratio to the illuminance distribution (Di) in the imaging target area (Ai) is extremely small and can be ignored.
  • the relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) illuminated by a plurality of light sources is determined. If the angle of the vertical line to the imaging target area (Ai) and the directional force of the light source from the light source to the point Mm and the radiation vector of the emitted light is ⁇ , the distance from the light source to the imaging target area (Ai) is L0. Therefore, the distance from one light source to the point Mm is LO / cos a.
  • the light at point Mm in the imaging target area (Ai) illuminated by the light emitted from each light source Intensity from each light source to point Mm Inversely proportional to the distance LO / cos a. Furthermore, the degree of decrease in luminous flux due to the tilt of the surface at the same point Mm is cos a.
  • the intensity of the light emitted from the light source in the direction of the radiation vector that forms an angle ⁇ with the vertical line with respect to the imaging target area (Ai) is the emission of the light emitted from the light source.
  • the radiation vector distribution (envelope) of a light source such as an actual LED has a complicated shape, but it is approximated by a circle or ellipse for convenience of calculation. For example, as shown in (1) of Fig.
  • A is the relative value of the total amount of light emitted by the kth light source.
  • ⁇ is the direction force at the point Mm with respect to the direction of the optical axis of the imaging lens, and the radiation plate k of the kth light source
  • the center line of the imaging target area (Ai) (illuminated by the entire light source placed in the upper half of the CU Illuminance distribution over the entire area (Ai) can be obtained, and the center line of the imaging target area (Ai) (the imaging target area (Ai) illuminated by the entire light source placed in the lower half from the CU)
  • the center line of the imaging target area (Ai) (the imaging target area (Ai) illuminated by the entire light source placed in the lower half from the CU)
  • the luminous flux emitted from the light source is used for both the center line (when calculating the lower half from the CU and when calculating the upper half, so the relative intensity A of the light source was placed at other positions.
  • FIG. 5 is a diagram showing a specific example of a target illuminance distribution (required illuminance distribution) when illuminating the imaging target area (Ai) so that the relative brightness of an image formed on the one-dimensional CCD is constant. .
  • the degree of illuminance that must be improved at both ends of the imaging target area (Ai) is 123% with respect to the illuminance at the center of the imaging target area (Ai).
  • the degree of illuminance that must be improved at both ends of the imaging target area (Ai) is 156% with respect to the illuminance at the center of the imaging target area (Ai). .
  • Figure 26 (b) is a diagram (enlarged view) showing the difference between the calculated relative illuminance I (Mm) and the required relative illuminance.
  • the graph (1) shows the illuminance distribution in the entire area to be imaged (Ai) illuminated by the light source in the center line (CU force, half area). 2) shows the illuminance distribution over the entire area to be imaged (Ai) illuminated by the light source in the other half of the area on the opposite side of the graph (1) .
  • Graph (3) shows the graphs (1) and (2 Graph (4) is normalized so that the center value of graph (3) is 100.
  • Graph (5) is the same as graph (4) and Fig. 26 (a). This is the difference from graph (4) in Fig. 25.
  • the imaging target area (Ai) The illuminance distribution near both ends of the [0252]
  • the difference shown in the graph (7) is less than ⁇ 1 (%), and the difference shown in the graph (6) is also less than ⁇ 2 (%). That is, the relative illuminance of the imaging target area (Ai) illuminated by a plurality of light sources can be brought close to the target illuminance distribution with very high accuracy.
  • the width of the area illuminated by the light source in the main scanning direction (Sx) is increased by about 2 to 3% (or illumination by the light source in the main scanning direction (Sx)).
  • the illuminance distribution of the imaging target area (Ai) illuminated by the light source can be further adapted to the target illuminance distribution.
  • the difference between the illuminance distribution of the imaging target area (Ai) illuminated by the light source and the target illuminance distribution can be less than ⁇ 1%. It is.
  • the above-mentioned difference in which the fluctuation of the illuminance distribution due to errors in parts accuracy or assembly accuracy is larger than the above difference is not a problem.
  • FIG. Fig. 27 is a diagram for realizing an illuminating device that matches the illuminance distribution of the light that illuminates the imaging target area (Ai) with the 1 / cos 4 ⁇ characteristic by adjusting the interval between the plurality of light sources.
  • FIG. Fig. 27 (a) is a top view of an example of an illuminating device that matches the illuminance distribution of the light that illuminates the imaging target area (Ai) to the 1 / cos 4 ⁇ characteristic by adjusting the interval between the multiple light sources. Yes, it shows one of the peripheral parts of the imaging target area (Ai) (the other peripheral part from the central part is omitted).
  • Figure 27 (b) shows an illumination that matches the illuminance distribution of the light that illuminates the imaging area (imaging target area) (Ai) with the 1 / cos 4 ⁇ characteristic by adjusting the interval between the multiple light sources. It is a front view of the example of an apparatus.
  • the illumination device includes a plurality of LEDs arranged in the main scanning direction (Sx) as a plurality of light sources.
  • the luminous flux of light emitted from each LED is collimated by a hood lens that is a convex lens corresponding to the LED, then condensed once by an illumination lens (3) that is a cylinder lens, and then diverged.
  • the illumination target area (Ai) is illuminated.
  • the plurality of LEDs are arranged so that the interval between the plurality of LEDs becomes narrower from the vicinity of the center line of the lighting device toward the periphery of the lighting device in accordance with the result of the above simulation.
  • the order of the number k of the LED spacing w in Fig. 27 (a) is k
  • the positions P to P of the respective light sources that are separated from the area (Ai) by the distance L0 are the illumination devices shown in FIG.
  • the position corresponds to the focal position (focal length f) of the cylinder lens corresponding to each LED.
  • the focus position of the cylinder lens corresponding to each LED can be regarded as a virtual light source position.
  • the configuration of the illumination device in the eleventh embodiment in the sub-scanning direction (Sy) is the same as that of the illumination device in the first to ninth embodiments of the present invention in the sub-scanning direction (Sy). There is no need to change.
  • Fig. 27 (b) the light flux emitted from each LED is converted into parallel light by the hood lens corresponding to the LED, and then transmitted through the illumination lens (3), which is a cylinder lens, as parallel light.
  • the method of focusing on the illumination target area (Ai) by the focusing mirror (4b) is shown.
  • a plane mirror is used instead of the focusing mirror to irradiate the imaging target area (Ai) as parallel light, it does not deviate from the results of the above simulation.
  • a hood lens that is a convex lens is used as a means for collimating the light emitted from the LED of the light source.
  • a hood lens that is a convex lens is used as a means for collimating the light emitted from the LED of the light source.
  • the hood lens instead of the hood lens, as shown in FIG. You can use a rotating parabolic mirror!
  • the intervals between the plurality of light sources arranged in the main scanning direction (SX) are set according to the simulation results as described above. It may be changed.
  • a set of red (R), green (G), and blue (B) LEDs is used as a light source.
  • the interval between the red (R), green (G), and blue (B) LED pairs may be changed according to the simulation results described above. .
  • the illuminance distribution of light that illuminates the imaging target area (Ai) by adjusting the distance from each of the plurality of light sources to the imaging target area (Ai) is 1 / cos 4
  • An example of matching with the characteristic of ⁇ is shown.
  • FIG. 28 is a diagram for explaining how to obtain a specific arrangement of a plurality of light sources that illuminate the imaging target area (Ai) so that the relative brightness of the image formed on the one-dimensional CCD is constant. It is.
  • FIG. 28A is a diagram showing the arrangement of a plurality of light sources and the position of the mirror surface on which the side mirror is arranged
  • FIG. 28B is a diagram showing an example of the radiation characteristics of the light sources.
  • the interval between the plurality of light sources in the main scanning direction (Sx) is constant, but the illumination target region (imaging target region) (Ai) from each of the plurality of light sources Change the distance to.
  • the symbol in FIG. 28 is the same force as the symbol in FIG. 24.
  • the intervals between the plurality of light sources wl, w2, ••• wnii are constant and equal to Wh / N.
  • the intervals wl, w2, •• wntt of a plurality of light sources, and half the length Wh of the imaging target area (Ai) in the main scanning direction (Sx) are given by N.
  • ⁇ is the center of the imaging lens relative to the optical axis of the imaging lens Is an angle of a straight line connecting the kth division point on the imaging target area (Ai). That is, the illumination target surface (imaging area) (Ai) from the light source arranged at the kth position P among the plurality of light sources.
  • the distance Lk to is imaged by the imaging lens according to the cosine fourth law with respect to ⁇ .
  • the decrease in brightness of the captured image is captured from the position P of the light source provided on the optical axis of the imaging lens.
  • the relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) irradiated with light emitted from a plurality of light sources is the same as that in the first embodiment of the present invention. In the same way, the formula
  • FIG. 29 shows the difference between the calculation result of relative illuminance I (Mm) and the required relative illuminance among the simulation results of relative illuminance in the twelfth and subsequent embodiments of the present invention.
  • the imaging target area (Ai) Since the position P force is also a virtual light source that is a mirror image of the light source up to position P, the imaging target area (Ai)
  • the illuminance distribution can be controlled to some extent.
  • the maximum value of the difference shown in graph (1) in Fig. 29 is about ⁇ 3%, even if this is the case.
  • the force S which is about twice the maximum value of the difference shown in Fig. 26, and the accuracy of the parts From the point of view of assembly accuracy and energy saving! (Even if you change the amplification factor of the electrical signal after converting the light amount into an electrical signal with a one-dimensional CCD and correct the difference, the change in the amplification factor is not affected by the small noise.)
  • FIG. 30 is by adjusting the distance from each of the plurality of light sources to the imaging area (imaging target region) (Ai), the illuminance distribution of the light illuminating the imaging area (Ai) l / cos 4 6 It is a conceptual diagram for implement
  • FIG. 30 (a) is a top view thereof
  • FIG. 30 (b) is a front view thereof. Note that the method of embodying the concept shown in FIG. 30 and mounting it on the first traveling body is in accordance with the method of Example 11 described above, and can be easily implemented by those skilled in the art.
  • FIG. 31 is a diagram for explaining an example of a method for changing the radiation characteristic of light emitted from a light source.
  • FIG. 31 is a view seen from the same direction as the top view shown in FIG. In FIG. 31, the front view is omitted, but the same configuration as FIG. 30 (b) is shown.
  • the light source LED is placed at the focal point of the convex lens (focal length fO) which is also a hood.
  • a convex cylinder lens (focal length fl) having the same focal length as that of the convex lens is arranged on the front surface of the convex lens so that the optical axis of the convex lens coincides with the optical axis of the convex cylinder lens.
  • a virtual light source having radiation characteristics similar to the radiation characteristics of the light emitting source can be formed at the focal position of the convex cylinder lens. For example, as shown in (1) of FIG.
  • the relationship between the shape of the convex lens and the shape of the convex cylinder lens is any one of (1), (2) and (3) in FIG. Are arranged in the main scanning direction (Sx).
  • the light flux emitted from each light emitting source LED is collimated by a corresponding hood lens that is a convex lens and then collected by an illumination lens (3) that is a convex cylinder lens. Light and diverge.
  • the periphery of the imaging area (Ai) is more than the focal position (virtual light source position) of the convex cylinder lens disposed on the center line side of the imaging area (Ai).
  • the pair of light source LED, convex lens, and convex cylinder lens is placed so that the focal position (imaginary light source position) of the convex cylinder lens placed on the side is close to the imaging area (Ai). More specifically, the distance between the imaging area (Ai) and the focal position of the convex cylinder lens (the position of the virtual light source) is the relative brightness of the image formed on the one-dimensional CCD by the imaging lens. Is proportional and given by X cos 40 . In FIG. 30 (a), the number of light sources is 10
  • the number of light sources was set to 25.
  • FIG. 30 (b) only the combination of the light source, the convex lens, and the convex cylinder lens at the center and one end in the main scanning direction (Sx) is shown, and the other light source, convex lens, and The convex cylinder lens is omitted.
  • the light flux emitted from each light emitting source LED is converted into parallel light by a hood lens that is a convex lens corresponding to the LED.
  • the light passes through the illumination lens (3), which is a convex cylinder lens, as parallel light and is focused on the imaging area (imaging target area) (Ai) by the focusing lens (4a) (or focusing mirror).
  • the distance from the imaging area (Ai) to the light source varies between the central part and the peripheral part in the main scanning direction (Sx), but the distance from the focusing lens (4a) (or focusing mirror) to the imaging area (Ai) Since the distance to the light source is constant, the degree of focusing of the light emitted from the light emitting source LED does not vary depending on the position of the light source in the main scanning direction (Sx). In other words, in the sub-scanning direction (Sy), the distance from the illumination lens (3) to the focusing lens (4a) (or focusing mirror) fluctuates, but the luminous flux from the illumination lens (3) to the focusing lens (4a ) (Or focusing mirror) is parallel light.
  • the light beam is focused Since the distance from the focusing lens (4a) (or focusing mirror) to the imaging area (Ai) is constant, the degree of focusing of light does not vary. It is not always necessary to insert the focusing lens (4a) (or focusing mirror). That is, when taking into consideration the floating of the document, it is preferable not to use the focusing lens (4a) (or the focusing mirror). However, even in this case, the purpose of making the relative brightness of the image formed on the one-dimensional CCD constant is not impaired.
  • the illuminance distribution of light that illuminates the imaging target area (Ai) is adjusted to 1 / cos 4 ⁇ by adjusting the radiation characteristics of the light emitted from the plurality of light sources.
  • An example of matching is shown.
  • FIG. 32 is a diagram for explaining a specific arrangement of a plurality of light sources that illuminate the imaging target region so that the relative brightness of the image formed on the one-dimensional CCD is constant.
  • FIG. 32 (a) is a diagram showing the arrangement of a plurality of light sources and the position of the mirror surface on which the side mirror is arranged
  • FIG. 32 (b) is a diagram showing an example of the radiation characteristics of the light sources.
  • the symbols in FIG. 32 are the same as the symbols in FIG. 24.
  • the distance between the light sources in the main scanning direction (Sx) and the illumination target area (imaging target area) (Ai) The distance to is constant. That is, in FIG. 32 (a), the intervals wl, w2, ••• wnii of the plurality of light sources are constant and equal to Wh / N. In other words, the intervals wl, w2, ••• wntt of the plurality of light sources are given by dividing the half Wh of the length of the imaging target area (Ai) in the main scanning direction (Sx) into N equal parts.
  • the distance from each of the plurality of light sources to the illumination target area (imaging target area) (Ai) is L. However, it is emitted from each light source.
  • the light radiation characteristics are changed.
  • ⁇ is the center of the imaging lens and the area to be imaged with respect to the optical axis of the imaging lens.
  • the radiation characteristics of the light emitted from the light source arranged at the kth position P among the plurality of light sources are
  • R k T k 2 -cos B (k) a k
  • T 2 is emitted from the light source at the kth position P.
  • the intensity of the vector vector in the vertical direction with respect to the illumination target surface (imaging area) (Ai), and B (k) is the light emission emitted from the light source at the kth position P.
  • the relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) irradiated with light emitted from a plurality of light sources is the same as in the twelfth embodiment of the present invention.
  • Position P force Because it is a virtual light source that is a mirror image of the light source up to position P, the light emission characteristics of the light source
  • the maximum value of the difference is about ⁇ 5%, which is slightly larger than the maximum value of the difference shown in the drawing (1) in FIG.
  • the maximum value of such a difference is almost a problem with regard to the accuracy of parts and assembly, as well as the power and displacement from the viewpoint of energy saving! /. (Even if you change the amplification factor of the electrical signal after converting the light quantity into an electrical signal with a one-dimensional CCD and correct the difference, the change in the amplification factor is hardly affected by the small noise. )
  • the illuminance distribution of the light that illuminates the imaging target area (Ai) is matched with the 1 / cos 4 ⁇ characteristics.
  • Figure 33 shows that the illuminance distribution of the light that illuminates the imaging area (imaging target area) matches the 1 / cos 4 ⁇ characteristics by adjusting the radiation characteristics of the light emitted from multiple light sources. It is a conceptual diagram for implement
  • FIG. 33 (a) is a top view thereof, and
  • FIG. 33 (b) is a front view thereof.
  • the focal lengths of the convex lenses corresponding to the plurality of light sources arranged in the main scanning direction (Sx) are constant and arranged in the main scanning direction (Sx).
  • Multiple light sources The focal length of the illumination lens (convex cylinder lens) (3) corresponding to is changed as shown in FIG.
  • the envelope of the radiation characteristic of the virtual light source formed at the focal position of the illumination lens is flat with strong dispersion as shown in Fig. 31 (2).
  • FIG. 33 (b) only the combination of the light source, the convex lens, and the convex cylinder lens at the center and one end in the main scanning direction (Sx) is shown, and the other light source, convex lens, and The convex cylinder lens is omitted.
  • the light flux emitted from each light emitting source LED is converted into parallel light by a hood lens that is a convex lens corresponding to the LED.
  • the light passes through the illumination lens (3), which is a convex cylinder lens, as parallel light, and is focused on the imaging area (Ai) by the focusing lens (4a) (or focusing mirror).
  • the focusing lens (4a) (or focusing mirror) force and imaging area ( Since the distance to Ai) is constant, the degree of focusing of the light emitted from the light source LED does not vary depending on the position of the light source in the main scanning direction (Sx). In other words, from the illumination lens to the focusing lens (4a) (or focusing mirror) in the sub-scanning direction (Sy). The distance from the illumination lens to the focusing lens (4a) (or the collecting mirror) is parallel light.
  • the degree of focusing of the light does not change. Note that it is not always necessary to insert the focusing lens (4a) (or the focusing mirror). That is, when taking into account the floating of the document, it is preferable not to use the focusing lens (4a) (or the focusing mirror). However, even in this case, the purpose of making the brightness of the image formed on the one-dimensional CCD constant is not impaired.
  • the fourteenth embodiment of the present invention shows an example of a concept of an illuminating device that approximates the illuminance distribution of light that illuminates the imaging region (imaging target region) (Ai) to the characteristic of 1 / cos 4 ⁇ .
  • Figure 34 shows that each force of multiple light sources is adjusted by adjusting the distance to the imaging area (Ai).
  • FIG. 5 is a conceptual diagram for realizing an illumination device that approximates the illuminance distribution of light that illuminates the imaging region (Ai) to the i / cos 4 e characteristic.
  • FIG. 34 (a) is a top view thereof, and FIG. 34 (b) is a front view thereof.
  • FIG. 34 (c) is a diagram showing an example of the illuminance distribution of the light illuminating the imaging area which is approximated to the characteristic of l / cos 4 6.
  • the illuminance distribution of the light that illuminates the imaging region (Ai) is 1 / cos.
  • the characteristics of the 4 theta has been described an example of a lighting device matching with good accuracy.
  • a configuration that can be manufactured more easily for example, by sacrificing the accuracy of the illuminance distribution of the light that illuminates the imaging area (Ai), which should have the characteristic of 1 / cos 4 ⁇ .
  • the illumination device according to the embodiment of the present invention shown in FIG. 34 can be more easily manufactured than the illumination device described in the twelfth embodiment of the present invention.
  • the difference between the ideal illumination distribution and the approximate illuminance distribution is the ideal cos 4 It is based on the difference between the position on the curve of ⁇ and the position on the side of the trapezoid of multiple light sources, and is very small.
  • Figure 34 (a) shows the trapezoidal characteristics of the target illuminance distribution of the light that illuminates the imaging area (Ai) by adjusting the distance to the imaging area (Ai) for each of the light sources.
  • the concept of the lighting device approximated by is shown.
  • the light source that gives the trapezoidal side characteristic parallel to the imaging area (Ai) in the trapezoidal characteristic is a light source or a virtual light source (here, an illumination lens (3 ) Is placed on a trapezoidal side parallel to the imaging area (Ai).
  • a light source that gives a characteristic of a side inclined with respect to the imaging region (Ai) in the trapezoidal characteristic is a light source or a virtual light source (here, the focal point of the illumination lens (3)), and the imaging region (Ai
  • the prism (7) is provided on the imaging region (Ai) side of the illumination lens (3) that is a cylinder lens.
  • the optical axis extending from the light source or the virtual light source is bent by the prism (7) by the prism (7) provided closer to the imaging area (Ai) than the illumination lens (3), and the bent optical axis becomes the imaging area. Be perpendicular to (Ai).
  • a flat plate can be used as the substrate for supporting the light source, which makes it easier to manufacture the lighting device.
  • a force S using a paraboloidal mirror is used to make the luminous flux emitted from the light source LED parallel light, and a shell-shaped hood lens is used. May be.
  • the relative position curve of multiple light sources, cos 4 ⁇ gives an ideal illumination distribution in the imaging area (Ai) with l / cos 4 e characteristics. Is divided into three in the range of the imaging region (Ai), but may be divided into two in the range of the imaging region (Ai) if the efficiency is sacrificed.
  • the curve of the relative position of the plurality of light sources may be approximated to a triangle whose vertex is a point on the curve at a position where the curve is divided into two.
  • the plurality of light sources are arranged only on the side inclined with respect to the imaging area (Ai). In this way, even if the relative position curve of the multiple light sources is approximated to a triangle by dividing into two in the range of the imaging area (Ai), compared with the case where the imaging area (Ai) is illuminated uniformly. The use efficiency of light emitted from the light source can be greatly improved.
  • a curve of the relative positions of multiple light sources that give the ideal illuminance distribution in (Ai) to a polygon within the range of the imaging area (Ai).
  • the approximate trapezoidal or triangular vertex position in the twelfth embodiment may be approximated to a trapezoidal or triangular shape having a vertex at a position opposite to the plane parallel to the imaging area (Ai).
  • a flat plate can be used as the substrate for supporting the light source, and the manufacture of the lighting device becomes easier.
  • the light source is a combination of red (R), green (G), and blue (B) LEDs
  • red light, green light Chromatic aberration occurs between blue light.
  • the red light, the green light, and the blue light that have passed through the plurality of prisms are superimposed on each other in the imaging region (Ai) to provide almost white light illumination to the imaging region (Ai). Become. Therefore, in practice, chromatic aberration due to the prism is rarely a problem.
  • Example 15 the imaging region is adjusted both by adjusting the distance from each of the plurality of light sources to the imaging region (Ai) and by adjusting the radiation characteristics of the light emitted from the plurality of light sources.
  • An example of matching the illuminance distribution of the light illuminating with the 1 / cos 4 ⁇ characteristic is shown.
  • FIG. 35 is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate the imaging target area (Ai) so that the relative brightness of an image formed on the one-dimensional CCD is constant.
  • FIG. 35 (a) is a diagram showing the arrangement of a plurality of light sources and the position of the mirror surface on which the side mirror is arranged
  • FIG. 35 (b) is a diagram showing an example of the radiation characteristics of the light sources.
  • the intervals between the plurality of light sources in the main scanning direction (Sx) are constant, but the illumination target region (imaging target region) (Ai) from each of the plurality of light sources And the radiation characteristics of light emitted from multiple light sources.
  • the meaning of the symbol in FIG. 35 is the same as the symbol in FIG. 24, and the intervals wl, w2, ⁇ ⁇ between the light sources are constant and equal to Wh / N.
  • the intervals wl, w2, •• wnii of a plurality of light sources are given by dividing the half Wh of the length of the imaging target area (Ai) in the main scanning direction (Sx) into N equal parts.
  • the shape factor b of B (k) in the equation is half the value of b in the thirteenth embodiment of the present invention.
  • the relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) irradiated by the light emitted from the plurality of light sources is the twelfth aspect of the present invention.
  • the imaging target area (Ai) Since the position P force is also a virtual light source that is a mirror image of the light source up to position P, the imaging target area (Ai)
  • the imaging area (Ai) The illuminance distribution near both ends can be controlled to some extent.
  • the maximum value of the difference is about ⁇ 2.5%, which is smaller than the maximum value of the difference shown in the graphs (1) and (2) of FIG.
  • the difference is larger than the maximum value shown in FIG. 26, such a maximum difference is hardly a problem from the viewpoints of component accuracy, assembly accuracy, and energy saving. ! / once Even if the gain of the electrical signal after changing the light amount into an electrical signal with the original CCD is changed and the difference is corrected, the amount of change in the amplification rate is hardly affected by the noise.
  • the illuminance distribution of the light that illuminates the imaging region is 1 / cos by both adjusting the distance from each of the plurality of light sources to the imaging region and adjusting the radiation characteristics of the light emitted from the plurality of light sources. 4 Shows the concept of lighting equipment that matches the characteristics of ⁇ .
  • FIG. 36 illuminates the imaging area (Ai) by adjusting both the distance from each of the multiple light sources to the imaging area (Ai) and adjusting the radiation characteristics of the light emitted from the multiple light sources. It is a conceptual diagram for realizing an illumination device that matches the illuminance distribution of light with the 1 / cos 4 ⁇ characteristic.
  • FIG. 36 (a) is a top view thereof
  • FIG. 36 (b) is a front view thereof.
  • the focal lengths of the convex lenses corresponding to the plurality of light sources arranged in the main scanning direction (Sx) are constant and arranged in the main scanning direction (Sx).
  • the focal length of the illumination lens (convex cylinder lens) (3) corresponding to a plurality of light sources varies as shown in FIG.
  • the envelope of the radiation characteristics of the virtual light source formed at the focal position of the illumination lens is flat with strong dispersion as shown in Fig. 31 (2).
  • each light source can be arranged so that the distance from the position of each light source to the illumination target surface (imaging region) (Ai) is constant. of
  • a light source can be provided on a flat plate as a substrate. As a result, the lighting device can be more easily manufactured.
  • the simulation was performed with the number of light sources set to 25, in FIG. 36 (a), the number of light sources is shown as ten.
  • the light flux emitted from each light emitting source LED is flattened by a hood lens that is a convex lens corresponding to the LED.
  • the illumination lens which is a convex cylinder lens, as parallel light, and is focused on the imaging target area (Ai) by the focusing lens (4a) (or the focusing mirror).
  • the focusing lens (4a) or the focusing mirror.
  • the purpose of making the brightness of the image formed on the one-dimensional CCD constant is not impaired.
  • the illuminance distribution of the light that illuminates the imaging region by adjusting the angle of the illumination optical axis of the light emitted from the plurality of light sources has a characteristic of 1 / cos 4 ⁇ .
  • An example of matching is shown below.
  • FIG. 37 is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate the imaging target area (Ai) such that the relative brightness of an image formed on the one-dimensional CCD is constant.
  • FIG. 37 corresponds to an enlarged view on the left side of the imaging target surface in FIG.
  • the symbols in Fig. 37 correspond to the symbols in Fig. 32.
  • the illumination distribution in the imaging target area (Ai) has the characteristic of 1 / cos 4 ⁇ . Adjust the angle of the illumination optical axis.
  • a mirror surface (side mirror) is placed at the position of the outside PM1.
  • This mirror surface is the object to be imaged It is placed on the light source placement position corresponding to the point where the range of area (Ai) is divided! / Reflects the light beam emitted from multiple light sources, and whether the light source is on the extension line In this way, the illumination target area (Ai) is illuminated.
  • it corresponds to the position of the dividing points P 1,.
  • the position of the virtual image (virtual light source VLS) obtained by the side mirror is P, P, ... n + 1 n + 2
  • the illumination optical axis of light that also emits force is tilted by an angle / 3 with respect to the vertical direction of the illumination target surface (imaging area) (Ai) (the angle of the optical axis of the light source at position P is / 3).
  • the angle / 3 of the illumination optical axis of the 00 00 k light source is directly connected from the point P00 to the position P of the light source.
  • the line is an angle formed with the center line CL of the imaging target area (Ai).
  • the angle is made with the center line CL of the imaging target area (Ai). That is, the angle of the illumination optical axis of the light source at the position P with respect to the center line CL of the imaging target area (Ai) is ⁇ .
  • the angle / 3 of the illumination optical axis with respect to the light source position P exceeding the angle / 3 increases as k increases.
  • the angle ⁇ 0 when P becomes P.
  • the optical axis of the light source of ⁇ located at an angle ⁇ or more should face the end of the imaging target area (Ai) up to ⁇ .
  • the mirror surface of the side mirror should be as close as possible to the light source at position ((until the side mirror as a plane mirror contacts the light source at position ⁇ Move the mirror closer to the light source at position Pn . ) I like it! /
  • a side mirror PM2 that forms a pair with a side mirror provided outside the light source at position P is also provided in the upper half area with respect to the center line of the imaging target area (Ai).
  • the side mirrors provided outside the light source are arranged in parallel to each other. For this reason, an infinite number of imaginary light sources, which are mirror images of the imaginary light source, are generated by the pair of side mirrors. It occurs at a distant position. For this reason, the contribution ratio of the mirror image of the imaginary light source to the illuminance distribution in the imaging target area (Ai) is extremely small and can be ignored.
  • the relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) illuminated by a plurality of light sources is determined. From the light source to the illumination target area (Ai), the vertical line to the illumination target area (imaging target area) (Ai) and the angle of the radiation vector of the emitted light directed to the point Mm from the light source is ⁇ . Since the distance force S and L0 of a single light source force, the distance to the point Mm is LO / cos a.
  • the point of the illumination target area (Ai) illuminated by the light emitted from each light source The intensity of light at Mm is inversely proportional to the distance LO / cos a from each light source to point Mm. Furthermore, the degree of decrease in the luminous flux due to the tilt of the surface at the same point Mm is cos a.
  • the intensity of light emitted from the light source in the direction of the radiation vector that forms an angle ⁇ with the vertical line with respect to the illumination target region (imaging target region) (Ai) Depends on the distribution (envelope) of the radiation vector of light emitted from.
  • the radiation distribution (envelope) of a light source such as an actual LED has a complex shape, but it is approximated by a circle or ellipse for convenience of calculation. For example, as shown in (1) of FIG.
  • the envelope of the radiation vector of the light emitted from the light source when the envelope of the radiation vector of the light emitted from the light source can be approximated to a circle, the direction of the radiation vector forming an angle ⁇ with respect to the illumination optical axis of the light source The intensity of light emitted from the light source is reduced by cos ⁇ .
  • the envelope of the radiation vector of the light emitted from the light source can be approximated to an ellipse, the light source is emitted in the direction of the radiation vector that forms an angle ⁇ with the vertical line with respect to the illumination target area (imaging target area) (Ai).
  • the degree of decrease in light intensity depends on the shape of the envelope of the radiation vector, cos 2 ⁇ as shown in Fig. 24 (2), and in Fig. 24 (3). It is possible to approximate such as cos 4 ⁇ as shown.
  • I (Mm) A k -cos 2 a k 'cos- k ) (but ⁇ k ⁇ )
  • A is the relative value of the total amount of light emitted by the kth light source.
  • ⁇ is the direction force at point Mm with respect to the vertical line of the illumination target area (Ai), and the radiation of the kth light source k
  • the angle of the vector. A is a coefficient approximating the envelope of the radiation vector of the light source.
  • a l
  • the envelope of the light source radiation vector is elliptical.
  • the light is emitted from the light source arranged at the position P.
  • the radiation vector of the light source that reaches the point Mm of the illumination target area (Ai) has a straight line angle ⁇ between the position P with respect to the vertical line of the illumination target area (Ai) and the point Mm.
  • the illumination optical axis of the light source placed at position P is tilted by 0 k with respect to the vertical line of the elephant area (Ai)
  • the illumination distribution over the entire area and the center line of the illumination target area (Ai) (over the entire illumination target area (Ai) illuminated by the whole light source placed in the upper half
  • the illuminance distribution over the entire area to be illuminated (Ai) illuminated by all the light sources can be obtained (however, if this calculation is performed, place it on P
  • the luminous flux emitted from the light source is the center line (used to calculate the lower half of the CU force and the upper half, so the relative intensity A of the light source is placed at other positions.
  • FIG. 38 is a diagram showing simulation results for the difference between the relative illuminance and the target illuminance distribution in the sixteenth practical example of the present invention.
  • the entire imaging target region (Ai) illuminated by the plurality of light sources is processed in the same manner as in the twelfth embodiment of the present invention.
  • the illuminance distribution over the area was obtained.
  • a graph similar to FIG. 25 was obtained.
  • FIG. 38 shows only an enlarged view of the difference between the illuminance distribution and the target illuminance distribution over the entire area to be imaged (Ai) illuminated by a plurality of light sources.
  • Figure 38 shows the difference between the obtained illuminance distribution and the target illuminance distribution at any position of the imaging target area (Ai), and the illuminance at the periphery of the imaging target area (Ai)
  • the illuminance at the end of the imaging target area (Ai) and the central part of the imaging target area (Ai) are almost the same.
  • the maximum value of the difference shown in the graph of Fig. 38 is slightly more than + 8% at a position 15% inside from the extreme end in the imaging target area (Ai).
  • the ratio of the amount of light discarded at the center of the imaging target area (Ai) is 23%, so the imaging target area (Ai) is illuminated uniformly.
  • the utilization efficiency of the light emitted from the light source can be greatly improved. If there is a difference of this level, change the amplification factor of the electric signal after converting the light amount into an electric signal with a one-dimensional CCD. Even if the difference is corrected, the rate of change in the amplification factor is hardly affected by the small noise.
  • Figure 39 shows that the illuminance distribution of the light that illuminates the imaging area (Ai) matches the 1 / cos 4 ⁇ characteristics by adjusting the angle of the illumination optical axis of the light emitted from multiple light sources. It is a conceptual diagram for implement
  • FIG. 39 (a) is a top view thereof, and
  • FIG. 39 (b) is a front view thereof.
  • the light source LED and the convex lens form a virtual light source as shown in FIG.
  • a means for inclining the illumination optical axis of the light source with respect to the center line of the illumination target area (imaging area) (Ai) as shown in FIG. 34, immediately after the illumination lens (3) of the convex cylinder lens Can be used.
  • the intervals between the plurality of light sources are equal, but also in the illumination device shown in FIG. 39, the intervals between the plurality of light sources themselves are equal.
  • the position of the virtual light source is displaced from the illumination optical axis of the light source while the illumination optical axis of the optical axis is inclined.
  • the straight line connecting the edges of Ai) increases as the position of the virtual light source is closer to the edges.
  • the distance between the virtual light sources included in the area outside the line becomes smaller as the position of the virtual light source is closer to the edge, so that the simulated lighting device shown in FIG. Strictly speaking, it is necessary to shift the position of the light source in response to the displacement of the position of the virtual light source.
  • the displacement of the position of the virtual light source is not a big problem.
  • the radiation characteristic of the illumination lens (3) inside the edge line EL is made relatively divergent, and the illuminance at the center of the imaging area (Ai) is relatively reduced, and the illumination lens ( The radiation characteristics of 3) are made relatively convergent, and the illuminance in the peripheral area of the imaging area (Ai) is relatively increased. As a result, the difference peak size shown in FIG. 38 can be reduced.
  • the force S can further reduce the size of the difference peak shown in FIG.
  • the light beam from the light source LED is made to be substantially parallel light, and then the convex cylinder lens is used only in the main scanning direction (Sx) with a convex cylinder lens. It has been explained that a virtual light source is formed by focusing once on the focal point. However, even if the convex cylinder lens is replaced with a concave cylinder lens, a virtual light source can be formed from the light source.
  • FIG. 40 is a diagram for explaining the formation of the virtual light source VLS from the light source using the concave cylinder lens.
  • 40 (a) is a top view of an optical system using a concave cylinder lens
  • FIG. 40 (b) is a front view of the optical system using a concave cylinder lens.
  • the light flux emitted from the light emitting light source LED is made to be approximately parallel light using a convex lens, and then can be diverged only by the concave cylinder lens in the main scanning direction (Sx). .
  • the position of the virtual light source with respect to the light source is formed at the focal point of the concave cylinder lens (focal length fl) as shown in FIG.
  • a concave cylinder lens By using a concave cylinder lens, a concave cylinder lens
  • the virtual light source VLS can be positioned closer to the light source side (when a convex cylinder lens is used, the virtual light source is formed on the imaging region (Ai) side than the concave cylinder lens). For this reason, the illumination device can be made smaller by appropriately selecting the focal length fl of the concave cylinder lens.
  • LED light emitting diode
  • a single light source such as red (R), green (G), blue (B), etc. alone is used as a light emitter.
  • a device such as a blue LED or a purple LED that emits a luminous flux to a phosphor to obtain white light can be applied to the apparatus of the present invention.
  • a neon tube, a discharge lamp such as a small high-pressure mercury lamp, or a small bulb-shaped filament bulb can be applied.
  • 41 and 42 are diagrams illustrating optical components that can be used in the embodiments and examples of the present invention.
  • FIG. 41 (a) is a diagram showing an example of the first cylinder lens array.
  • the first cylinder lens array as shown in FIG. 41 (a) is composed of a plurality of convex cylinder lenses arranged adjacent to each other, and is used as an illumination lens in the embodiments and examples of the present invention. obtain.
  • FIG. 41 (b) is a diagram showing an example of the second cylinder lens array.
  • the first cylinder lens array as shown in FIG. 41 (b) is composed of a plurality of concave cylinder lenses arranged adjacent to each other, and is used as an illumination lens in the embodiments and examples of the present invention. obtain.
  • FIG. 41 (c) is a diagram showing an example of the first cylinder lens.
  • the first cylinder lens as shown in FIG. 41 (c) has a plano-convex cross section, and can be used as a focusing lens in the embodiments and examples of the present invention.
  • FIG. 41 (d) is a diagram showing an example of the second cylinder lens.
  • the second cylinder lens as shown in FIG. 41 (d) has a biconvex cross section, and can be used as a focusing lens in the embodiments and examples of the present invention.
  • Fig. 41 (e) is a diagram showing an example of a parabolic mirror or an ellipsoidal mirror.
  • a parabolic mirror or ellipsoidal mirror as shown in Fig. 41 (e) has a parabolic or elliptical cross section in one direction and a parallel plane in a direction perpendicular to that direction. It is a mirror which has the cross section.
  • a parabolic mirror or ellipsoidal mirror as shown in Fig. 41 (e) can be easily formed using a bright aluminum thin plate, so a parabolic mirror or ellipse as shown in Fig. 41 (e) is used. The cost for manufacturing the surface mirror can be reduced.
  • FIG. 41 (f) is a diagram showing an example of a plane mirror.
  • a plane mirror as shown in FIG. 41 (f) can be used as a turning mirror and a folding mirror in the embodiments and examples of the present invention.
  • the plane mirror as shown in FIG. 41 (f) is used as a turning mirror, in order to reflect light with image information, the plane mirror as shown in FIG. A plane mirror having one surface as a mirror surface is preferable.
  • the plane mirror as shown in FIG. 41 (f) is a plane mirror manufactured using a bright aluminum plate V. Moyore.
  • FIG. 42 (a) is a diagram showing a convex cylinder lens.
  • a convex cylinder lens as shown in FIG. 42 (a) can be used as an illumination lens in the embodiments and examples of the present invention.
  • FIG. 42 (b) is a diagram showing a concave cylinder lens.
  • a concave cylinder lens as shown in FIG. 42 (a) can be used as an illumination lens in the embodiments and examples of the present invention.
  • FIG. 42 (c) is a diagram showing a prism.
  • a prism as shown in FIG. 42 (c) can be used as an optical element that bends (deflects) the illumination optical axis in the embodiments and examples of the present invention.

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Abstract

A document illuminating method and device for illuminating a document with higher efficiency with light emitted from a light source. The method for illuminating a document with light emitted from a light source includes a step of illuminating a document with light produced by combining lights emitted from light sources arranged at least in a first direction and a step of diffusing the light beams emitted from the light sources so that each light beam is diffused to a light bema having a width two or more times the interval between adjacent light sources of the light sources in the first direction. The document illuminating device for illuminating a document with light emitted from a light source comprises light sources arranged at least in a first direction, and an optical system for combining lights emitted from the light sources, illuminating the document with the combined light, and diffusing each of the light beams emitted from the light sources to a light beam having a width two or more times the interval between adjacent light sources of the light sources in the first direction.

Description

明 細 書  Specification
原稿照明方法、原稿照明装置、及び画像読取装置  Document illumination method, document illumination apparatus, and image reading apparatus
技術分野  Technical field
[0001] 本発明は、原稿照明方法、原稿照明装置、及び画像読取装置に関する。  The present invention relates to a document illumination method, a document illumination device, and an image reading device.
背景技術  Background art
[0002] 従来、画像読取装置に関する様々な技術が提案されて!/、る。  [0002] Conventionally, various techniques related to an image reading apparatus have been proposed!
[0003] 例えば、特許文献 1には、光源により照明した原稿からの反射光を結像レンズで撮 像素子に結像させ、前記原稿の画像を読み取る画像読取装置であって、前記撮像 素子から前記結像レンズを見たときに該結像レンズの有効瞳の一部に重なる位置に 前記光源が設けられて!/、ることを特徴とする画像読取装置が、開示されて!/、る。  [0003] For example, Patent Document 1 discloses an image reading apparatus that reads reflected image from a document illuminated by a light source onto an imaging element with an imaging lens and reads the image of the document. Disclosed is an image reading apparatus characterized in that the light source is provided at a position that overlaps a part of an effective pupil of the imaging lens when the imaging lens is viewed! .
[0004] また、特許文献 2には、 1次元光源で原稿面を照明し、この原稿を走査することによ つて 1次元撮像素子と結像レンズによって線順次に原稿画像を読み取る画像読み取 り装置において、前記撮像素子と前記結像レンズの間に前記 1次元光源からの光を 前記結像レンズに導くハーフミラーを設置し、前記原稿面の垂線と前記結像レンズに よる読み取り光軸が一致しないように光学系を構成することを特徴とする画像読み取 り装置が、開示されている。  [0004] Further, Patent Document 2 discloses an image reading apparatus that illuminates a document surface with a one-dimensional light source and scans the document to read a document image line-sequentially with a one-dimensional imaging device and an imaging lens. A half mirror that guides the light from the one-dimensional light source to the imaging lens between the imaging element and the imaging lens, and the perpendicular of the document surface coincides with the optical axis of reading by the imaging lens. An image reading apparatus characterized in that the optical system is configured so as not to occur is disclosed.
[0005] ここで、特許文献 1及び 2に開示されるような、縮小光学系を有する一般的な画像 読取装置の例を、図 1を参照して、説明する。  Here, an example of a general image reading apparatus having a reduction optical system as disclosed in Patent Documents 1 and 2 will be described with reference to FIG.
[0006] 図 1 (a)及び (b)は、それぞれ、一般的な画像読取装置の概略図及びその副走査 方向における画像読取装置の断面図である。  FIGS. 1A and 1B are a schematic view of a general image reading apparatus and a cross-sectional view of the image reading apparatus in the sub-scanning direction, respectively.
[0007] 画像読取装置（100)においては、シート及び本のような原稿（107)は、透明ガラス のコンタクトガラス（原稿台）（108)上に置かれ、照明ランプ（109)からの光及び照明 ランプ（109)から漏れた光を受けたリフレクタ（110)からの反射光力 原稿（107)の 撮像領域 (Ai)に照射される。照明ランプ（109)は、例えば、冷陰極管であり、その管 壁の一部分が、窓である。照明ランプ（109)の光は、その窓を通じて、原稿（107)の 撮像領域 (Ai)に照射される。第 1走行体（103)は、照明ランプ（109)、リフレクタ（1 10)、及び変向ミラー（112)を一体に有し、第 2走行体（104)は、折り返しミラー A(l 11a)及び折り返しミラー B (11 lb)を有する。そして、撮像領域 (Ai)からの反射光が 、第 1走行体（103)内の変向ミラー（112)、第 2走行体（104)内の折り返しミラー A ( 11 la)及び折返しミラー B (11 lb)で反射されて、結像レンズ（102)によって、 1次元 撮像素子（101)に結像させられる。なお、折り返しミラー A(l 11a)及び折り返しミラ 一 B (11 lb)は、変向ミラー（112)からの反射光の画像の向きを維持する。また、結 像レンズ（102)は、一般には、鏡筒によって一体化された複数のレンズを含む光学 系である。このようにして、上記 1次元撮像素子（101)は、ライン状の撮像領域 (Ai) の 1次元的な画像を取得すると共に電気信号に変換する。 1次元撮像素子（101)に おいてこの 1次元的な画像を取得する方向を主走査方向（Sx)と呼ぶ。また、結像レ ンズ（102)及び 1次元撮像素子を含む系を、読取ユニットと呼ぶことがある。 In the image reading apparatus (100), an original (107) such as a sheet and a book is placed on a contact glass (original table) (108) made of transparent glass, and the light from the illumination lamp (109) and Light reflected from the reflector (110) receiving light leaked from the illumination lamp (109) is applied to the imaging area (Ai) of the document (107). The illumination lamp (109) is, for example, a cold cathode tube, and a part of the tube wall is a window. The light from the illumination lamp (109) is applied to the imaging area (Ai) of the document (107) through the window. The first traveling body (103) integrally includes an illumination lamp (109), a reflector (110), and a turning mirror (112), and the second traveling body (104) includes a folding mirror A (l 11a) and folding mirror B (11 lb). The reflected light from the imaging region (Ai) is reflected by the turning mirror (112) in the first traveling body (103), the folding mirror A (11 la) and the folding mirror B (in the second traveling body (104). 11 lb) and is imaged on the one-dimensional image sensor (101) by the imaging lens (102). The folding mirror A (l 11a) and the folding mirror B (11 lb) maintain the direction of the image of the reflected light from the turning mirror (112). The imaging lens (102) is generally an optical system including a plurality of lenses integrated by a lens barrel. In this way, the one-dimensional imaging device (101) acquires a one-dimensional image of the line-shaped imaging region (Ai) and converts it into an electrical signal. The direction in which the one-dimensional image sensor (101) acquires this one-dimensional image is called the main scanning direction (Sx). In addition, a system including the imaging lens (102) and the one-dimensional image sensor may be referred to as a reading unit.
[0008] また、この画像読取装置（100)では、上記第 1走行体（103)及び上記第 2走行体（  In the image reading apparatus (100), the first traveling body (103) and the second traveling body (
104)力 モータ（105)による駆動力を、駆動伝達手段（106)を通じて受け、第 1走 行体（103)は、第 2走行体（104)の速度の 2倍である速度で走行する。その結果、コ ンタクトガラス（108)面に対する結像レンズ（102)の結像位置が、 1次元撮像素子（1 01)面に維持されつつ、光が、コンタクトガラス（108)面において、ライン状の撮像領 域 (Ai)と垂直な方向に且つコンタクトガラス（108)と平行に、走行する。このようにし て、コンタクトガラス（108)上に置かれた原稿（107)の画像を、 1次元撮像素子（101 )にて順次読み出して、 2次元に取得する。ここで、原稿（107)の読み取り領域は、 1 次元撮像素子（101)によって読み取られる範囲と第 2走行体（104)の走行距離との 積になる。なお、コンタクトガラス（108)に平行に上記第 1走行体（103)及び上記第 2走行体（104)が走行する方向を、副走査方向（Sy)と呼ぶ。副走査方向（Sy)は、 主走査方向（Sx)と直交する。  104) Force The driving force from the motor (105) is received through the drive transmission means (106), and the first traveling body (103) travels at a speed that is twice the speed of the second traveling body (104). As a result, the imaging position of the imaging lens (102) with respect to the contact glass (108) surface is maintained on the one-dimensional imaging device (101) surface, and light is linearly formed on the contact glass (108) surface. It travels in a direction perpendicular to the imaging area (Ai) and parallel to the contact glass (108). In this way, the image of the original (107) placed on the contact glass (108) is sequentially read out by the one-dimensional image sensor (101) and acquired in two dimensions. Here, the reading area of the document (107) is the product of the range read by the one-dimensional imaging device (101) and the traveling distance of the second traveling body (104). A direction in which the first traveling body (103) and the second traveling body (104) travel in parallel with the contact glass (108) is referred to as a sub-scanning direction (Sy). The sub-scanning direction (Sy) is orthogonal to the main scanning direction (Sx).
[0009] 通常、 1次元撮像素子として 1次元 CCD (単に CCDと呼ぶこともある）が用いられ、 結像レンズ（102)は、コンタクトガラス（108)の面上の画像を縮小して、その縮小され た画像を 1次元撮像素子（101)上に結像する。  [0009] Normally, a one-dimensional CCD (sometimes simply referred to as a CCD) is used as a one-dimensional imaging device, and the imaging lens (102) reduces the image on the surface of the contact glass (108), and The reduced image is formed on the one-dimensional image sensor (101).
[0010] また、上記第 1走行体（103)及び上記第 2走行体（104)の走行速度の比は、 2 : 1 に設定されるので、第 2走行体（104)の移動距離は、第 1走行体（103)の移動距離 の半分であり、撮像領域 (Ai)から結像レンズ（102)又は 1次元撮像素子（101)まで の距離は、第 1走行体（103)及び第 2走行体（104)の位置によらず、一定である。 [0010] Further, since the ratio of the traveling speeds of the first traveling body (103) and the second traveling body (104) is set to 2: 1, the moving distance of the second traveling body (104) is Half of the travel distance of the first traveling body (103), from the imaging area (Ai) to the imaging lens (102) or the one-dimensional imaging device (101) Is constant regardless of the positions of the first traveling body (103) and the second traveling body (104).
[0011] 通常、モノクロスキャナーでは、 1個の 1次元 CCDを用いており、スキャナの画像解 像度は、 DPI (ドット /inch)で表され、デジタル PPCに搭載されるスキャナの画像解 像度は、しばしば、 400〜600DPIである。一方、カラースキャナでは、 R (赤色）、 G ( 緑色）又は B (青色）の光のスペクトルに感度を有する三個の 1次元 CCDを用いてお り、それらの CCDから原稿までの光路長を共通にしている。し力、しな力 、（赤色）、 G (緑色）又は B (青色）用のカラーフィルターを備えた 3ラインの CCDを副走査方向（S y)に配置した 3ライン CCDを撮像素子として用いることもある。この場合、各画素列の 間の距離は、 CCD画素の主走査読取領域の 4〜8ドット程度であり、各画素列は、必 ずしも一体化されてない。よって、 3ライン CCDを上記画像読取装置の撮像素子とし て用いた場合、 RGBの CCD画素のそれぞれに対応する原稿の読取位置は、副走 查方向（Sy)で異なるため、原稿を照明する光を、それぞれの色に対応する読取位 置に照射する必要がある。 [0011] Normally, a monochrome scanner uses a single one-dimensional CCD, and the image resolution of the scanner is expressed in DPI (dots / inch), and the image resolution of the scanner installed in a digital PPC. Is often 400-600 DPI. On the other hand, color scanners use three one-dimensional CCDs that are sensitive to the spectrum of R (red), G (green), or B (blue) light. It is common. A three-line CCD with a color filter for lateral force, sinusoidal force (red), G (green) or B (blue) arranged in the sub-scanning direction (Sy) is used as the image sensor. Sometimes. In this case, the distance between the pixel columns is about 4 to 8 dots in the main scanning reading area of the CCD pixel, and the pixel columns are not necessarily integrated. Therefore, when a 3-line CCD is used as the image sensor of the image reading device, the reading position of the original corresponding to each of the RGB CCD pixels differs in the secondary scanning direction (Sy). It is necessary to irradiate the reading position corresponding to each color.
[0012] しかしながら、上述したような画像読取装置は、いくつかの問題点を有する。 [0012] However, the image reading apparatus as described above has several problems.
[0013] 図 2は、画像読取装置における原稿の照明に関する問題点の一つを説明する図で ある。 FIG. 2 is a diagram for explaining one of the problems related to illumination of a document in the image reading apparatus.
[0014] 画像読取装置の第 1走行体に搭載された冷陰極管の照明ランプ (201)において 発生した光は、蛍光面（202)で反射されて、冷陰極管の開口部（203)を通じて、照 明光（204)として放出される。照明ランプ（201)から放出された照明光（204)は、コ ンタクトガラス（205)に置かれた原稿の撮像領域 (Ai)を直接照明するか又は第 1走 行体に搭載されたリフレクタ（206)によって反射されて、原稿の撮像領域 (Ai)を照 明する。なお、図 2に、撮像領域 (Ai)付近における照明光（204)の照度分布 (Di)を 示す。  The light generated in the cold-cathode tube illumination lamp (201) mounted on the first traveling body of the image reading device is reflected by the fluorescent screen (202) and passes through the opening (203) of the cold-cathode tube. , Emitted as illumination light (204). The illumination light (204) emitted from the illumination lamp (201) directly illuminates the imaging area (Ai) of the document placed on the contact glass (205), or the reflector mounted on the first traveling body ( 206) to reflect the imaging area (Ai) of the document. Fig. 2 shows the illuminance distribution (Di) of the illumination light (204) in the vicinity of the imaging region (Ai).
[0015] しかしながら、第 1走行体に搭載された冷陰極管の照明ランプ (201)及びリフレクタ  However, the cold-cathode tube illumination lamp (201) and the reflector mounted on the first traveling body
(206)によって撮像領域 (Ai)を照明する照明光は、冷陰極管の照明ランプ (201) において発生する光の光量の 1 %未満であり、照明ランプ（201)及びリフレクタ（207 )によって撮像領域 (Ai)を照明する効率は、非常に低い。副走査方向（Sy)における 撮像領域 (Ai)の長さは、 1ライン CCDを用いる場合には、 0. 1mm程度の幅であり、 カラー原稿を読み取るための 3ライン CCDを用いる場合には、 1mm程度である。に もかかわらず、副走査方向（Sy)における照明光（204)の照度分布（Di)は、撮像領 域 (Ai)を中心に、数十 mmの広い範囲に広がっている。 The illumination light that illuminates the imaging area (Ai) by (206) is less than 1% of the amount of light generated in the cold-cathode tube illumination lamp (201), and is imaged by the illumination lamp (201) and reflector (207). The efficiency of illuminating area (Ai) is very low. The length of the imaging area (Ai) in the sub-scanning direction (Sy) is about 0.1 mm wide when using a 1-line CCD. When a 3-line CCD is used to read a color document, it is about 1 mm. Nevertheless, the illuminance distribution (Di) of the illumination light (204) in the sub-scanning direction (Sy) spreads over a wide range of several tens of mm centering on the imaging area (Ai).
[0016] また、照明ランプ（201)の冷陰極管それ自体及びその（高電圧を発生させる）点灯 装置の構成が複雑である。  [0016] Further, the configuration of the cold cathode tube itself of the illumination lamp (201) and the lighting device (which generates a high voltage) are complicated.
[0017] 図 3は、画像読取装置における原稿の照明に関する別の問題点を説明する図であ る。図 3に示すように、コンタクトガラス（301)に置かれたブック原稿（302)を読み取る 際に、リフレクタからの反射光による照度よりも照明ランプから直接照明される照明光 (303)による照度が数倍も高いので、ブック原稿（302)の中央部分（304)の読取位 置においては、照度が不足し、ブック原稿（302)の中央部分（304)が、黒い画像と して読み取られる部分 (Ad)が生ずることがある。  FIG. 3 is a diagram for explaining another problem relating to illumination of a document in the image reading apparatus. As shown in Fig. 3, when reading a book document (302) placed on the contact glass (301), the illuminance by the illumination light (303) directly illuminated from the illumination lamp is less than the illuminance by the reflected light from the reflector. Because it is several times higher, the reading position of the central part (304) of the book original (302) is insufficient in illuminance, and the central part (304) of the book original (302) is read as a black image. (Ad) may occur.
[0018] ところで、撮像領域 (Ai)を照明する効率を改善するために、光源に LED (発光ダイ オード）を用いる方法が、検討されてきた。  By the way, in order to improve the efficiency of illuminating the imaging area (Ai), a method using an LED (light emitting diode) as a light source has been studied.
[0019] 図 4は、複数の LEDで構成された光源及びその光源による照明を説明する図であ る。図 4 (a)は、光源を構成する単一の LEDチップを示す図である。図 4 (b)は、複数 の LEDで構成された光源の構成を説明する図である。図 4 (c)は、複数の LEDで構 成された光源によって照明された撮像領域 (Ai)における照度分布を説明する図で ある。  FIG. 4 is a diagram illustrating a light source composed of a plurality of LEDs and illumination by the light source. FIG. 4 (a) is a diagram showing a single LED chip constituting the light source. FIG. 4 (b) is a diagram for explaining the configuration of a light source composed of a plurality of LEDs. FIG. 4 (c) is a diagram illustrating the illuminance distribution in the imaging region (Ai) illuminated by a light source composed of a plurality of LEDs.
[0020] ここでは、図 4 (a)に示すような、長手方向（VI)及び短手方向（Vs)を備えた長方形 に切り出された LEDチップを用いる。図 4 (b)に示すように、図 4 (a)に示すような LE Dチップの長手方向（VI)に、複数の LEDチップを整列させて、光源を形成する。光 源は、複数の LEDが整列させられた方向（複数の LEDの長手方向）が、一次元撮像 素子の主走査方向（Sx)であるように、且つ、複数の LEDの短手方向が、一次元撮 像素子の副走査方向（Sy)であるように、配置される。このような整列された複数の L EDで構成される光源を用いて、照明対象領域 (Ai)を照明する。  Here, as shown in FIG. 4 (a), an LED chip cut into a rectangle having a longitudinal direction (VI) and a lateral direction (Vs) is used. As shown in FIG. 4 (b), a plurality of LED chips are aligned in the longitudinal direction (VI) of the LED chip as shown in FIG. 4 (a) to form a light source. The light source is such that the direction in which the plurality of LEDs are aligned (longitudinal direction of the plurality of LEDs) is the main scanning direction (Sx) of the one-dimensional image sensor, and the short direction of the plurality of LEDs is The one-dimensional imaging device is arranged so as to be in the sub-scanning direction (Sy). The illumination target area (Ai) is illuminated using a light source composed of a plurality of LEDs arranged in this way.
[0021] しかしながら、このような方法は、個々の LEDの間の発光量の差が、直接、光源に よる照明光の照度むらの発生を引き起こす。ここで、若干の照度むらを補正する技術 としては、シェーディング補正が知られている。すなわち、一次元撮像素子による走 查を開始する前に、主走査方向（Sx)について全白部分を一度読み取り、読み取ら れた全白部分における明度分布を基準にして、実際に読み取られた原稿の明度分 布を、電気的に補正することができる。し力、しながら、 LEDの製造上の理由から、 LE Dの発光効率においては、二倍以上のバラツキが生じること力 知られている。図 4 (c )に示すように、二倍以上のバラツキを備えた発光効率を有する複数の LEDを光源と して用いると、撮像領域 (Ai)において平坦である理想的な照度分布（Ideal— Di)に 対して、より高い照度 hiで照明される部分及びより低い照度 h2で照明される部分が 存在する。そして、照度 h2に対する照度 hiの比は、二倍以上になることがある。この ような照度分布 (Actual— Di)の変動は、複数の LEDの全体にわたって頻繁に生ず るので、照度分布 (Actual— Di)の変動を解消するためには、電気的な増幅器を用 いて、一次元撮像素子によって得られた信号に二倍以上の増幅率の変化を与えるこ とになる。その結果、より低い照度で照明された部分についての信号は、大きさノイズ を含む信号となり、読み取られた信号の品質を低下させることになる。一方、発光効 率のバラツキの無い又は少ない複数の LEDを選択的に用いて、光源を形成すること も考えられる。し力、しながら、発光効率のバラツキの無い又は少ない複数の LEDを選 別することは、複数の LEDで構成される光源の歩留まりを大きく低下させ、数倍のコ ストアップをもたらすことになる。 [0021] However, in such a method, the difference in the amount of light emission between the individual LEDs directly causes the illuminance unevenness of the illumination light by the light source. Here, shading correction is known as a technique for correcting slight illuminance unevenness. In other words, running with a one-dimensional image sensor Before starting wrinkle, the entire white part is scanned once in the main scanning direction (Sx), and the brightness distribution of the actually scanned document is electrically measured based on the brightness distribution in the scanned all white part. It can be corrected. However, for LED manufacturing reasons, it is known that the LED luminous efficiency will vary more than twice. As shown in Fig. 4 (c), when multiple LEDs with luminous efficiency with twice or more variations are used as the light source, an ideal illuminance distribution (Ideal— For Di), there are a part illuminated with higher illuminance hi and a part illuminated with lower illuminance h2. And the ratio of illuminance hi to illuminance h2 may be more than double. Such fluctuations in the illuminance distribution (Actual—Di) frequently occur throughout the LEDs, so an electrical amplifier is used to eliminate the fluctuations in the illuminance distribution (Actual—Di). In other words, the gain obtained by the one-dimensional image sensor is changed by a factor of two or more. As a result, the signal for the part illuminated with lower illuminance becomes a signal containing magnitude noise, which degrades the quality of the read signal. On the other hand, it is also conceivable to form a light source by selectively using a plurality of LEDs with little or no variation in luminous efficiency. However, selecting multiple LEDs with little or no variation in luminous efficiency will greatly reduce the yield of light sources composed of multiple LEDs, resulting in several times the cost increase. .
特許文献 1 :特開 2005— 204272号公報  Patent Document 1: JP 2005-204272 A
特許文献 2：特開 2005— 242263号公報  Patent Document 2: JP-A-2005-242263
発明の開示  Disclosure of the invention
発明が解決しょうとする課題  Problems to be solved by the invention
[0022] 本発明の第一の目的は、光源から放出される光でより高い効率で原稿を照明する ことが可能な原稿照明方法を提供することである。 A first object of the present invention is to provide a document illumination method capable of illuminating a document with higher efficiency with light emitted from a light source.
[0023] 本発明の第二の目的は、光源から放出される光でより高い効率で原稿を照明する ことが可能な原稿照明装置を提供することである。 [0023] A second object of the present invention is to provide a document illuminating device capable of illuminating a document with higher efficiency by light emitted from a light source.
[0024] 本発明の第三の目的は、光源から放出される光でより高い効率で原稿を照明する ことが可能な原稿照明装置によって照明された該原稿の画像を読み取る画像読取 装置を提供することである。 課題を解決するための手段 A third object of the present invention is to provide an image reading apparatus that reads an image of a document illuminated by a document illumination device capable of illuminating the document with light emitted from a light source with higher efficiency. That is. Means for solving the problem
[0025] 本発明の第一の態様は、光源から放出される光で原稿を照明する原稿照明方法 において、少なくとも第一の方向に配置された複数の光源から放出される光を重畳さ せて、該重畳された光で原稿を照明すること、及び、該複数の光源から放出される光 の光束を、該第一の方向において、該複数の光源における相互に隣接する光源の 間の間隔の二倍以上に拡散させることを含むことを特徴とする原稿照明方法である。  [0025] A first aspect of the present invention is a document illumination method for illuminating a document with light emitted from a light source, wherein light emitted from a plurality of light sources arranged at least in a first direction is superimposed. Illuminating the original with the superimposed light, and the light flux emitted from the plurality of light sources in the first direction with a distance between adjacent light sources in the plurality of light sources. An original illumination method including diffusing twice or more.
[0026] 本発明の第二の態様は、光源から放出される光で原稿を照明する原稿照明装置 において、少なくとも第一の方向に配置された複数の光源、及び、該複数の光源から 放出される光を重畳させて、該重畳された光で原稿を照明すると共に、該複数の光 源から放出される光の光束を、該第一の方向において、該複数の光源における相互 に隣接する光源の間の間隔の二倍以上に拡散させる光学系を含むことを特徴とする 原稿照明装置である。  [0026] A second aspect of the present invention is a document illumination device that illuminates a document with light emitted from a light source, and a plurality of light sources arranged in at least a first direction, and the plurality of light sources emitted from the plurality of light sources. And illuminating the original with the superimposed light, and causing the light flux emitted from the plurality of light sources to emit light beams adjacent to each other in the plurality of light sources in the first direction. An original illuminating device including an optical system for diffusing at least twice the distance between the two.
[0027] 本発明の第三の態様は、光源から放出される光で原稿を照明する原稿照明装置を 含むと共に該原稿照明装置によって照明された該原稿の画像を読み取る画像読取 装置において、該原稿照明装置は、少なくとも第一の方向に配置された複数の光源 、及び、該複数の光源から放出される光を重畳させて、該重畳された光で原稿を照 明すると共に、該複数の光源から放出される光の光束を、該第一の方向において、 該複数の光源における相互に隣接する光源の間の間隔の二倍以上に拡散させる光 学系を含むことを特徴とする画像読取装置である。  A third aspect of the present invention includes an original illuminating apparatus that illuminates an original with light emitted from a light source, and an image reading apparatus that reads an image of the original illuminated by the original illuminating apparatus. The illumination device superimposes a plurality of light sources arranged in at least a first direction and light emitted from the plurality of light sources to illuminate a document with the superimposed light, and the plurality of light sources An image reading apparatus comprising: an optical system for diffusing a light beam emitted from a light source in the first direction to at least twice an interval between adjacent light sources in the plurality of light sources. It is.
[0028] 本発明の第四の態様は、少なくとも第一の方向に配置された複数の光源、及び、 該複数の光源から放出される光を重畳させて、該重畳された光で原稿を照明すると 共に、該複数の光源から放出される光の光束を、該第一の方向において、該複数の 光源における相互に隣接する光源の間の間隔以上に拡散させる照明光学系を含む 原稿照明装置、該原稿照明装置によって照明された原稿から散乱又は反射された 画像を結像させる結像光学系、並びに、該結像光学系によって結像された光を撮像 する撮像素子を含む、該原稿の画像を読み取る画像読取装置において、該複数の 光源は、該原稿における該原稿を照明する光の照度分布特性が、該撮像素子に該 結像光学系によって結像される画像の明度の分布特性と逆であるように、配置される ことを特徴とする画像読取装置である。 [0028] A fourth aspect of the present invention provides a plurality of light sources arranged in at least a first direction, and superimposes light emitted from the plurality of light sources, and illuminates a document with the superimposed light. Then, an original illuminating apparatus including an illumination optical system that diffuses the light flux of light emitted from the plurality of light sources in the first direction more than a distance between adjacent light sources in the plurality of light sources, An image of the original including an imaging optical system that forms an image scattered or reflected from the original illuminated by the original illuminating device, and an imaging element that images the light imaged by the imaging optical system In the image reading apparatus, the plurality of light sources has an illuminance distribution characteristic of light illuminating the original on the original opposite to a brightness distribution characteristic of an image formed on the image sensor by the imaging optical system. Is arranged to be This is an image reading apparatus.
発明の効果  The invention's effect
[0029] 本発明の第一の態様によれば、光源から放出される光でより高い効率で原稿を照 明することが可能な原稿照明方法を提供することができる。  [0029] According to the first aspect of the present invention, it is possible to provide a document illumination method capable of illuminating a document with higher efficiency by light emitted from a light source.
[0030] 本発明の第二の態様によれば、光源から放出される光でより高い効率で原稿を照 明することが可能な原稿照明装置を提供することができる。 [0030] According to the second aspect of the present invention, it is possible to provide a document illumination device capable of illuminating a document with higher efficiency by light emitted from a light source.
[0031] 本発明の第三の態様によれば、光源から放出される光でより高い効率で原稿を照 明することが可能な原稿照明装置によって照明された該原稿の画像を読み取る画像 読取装置を提供することができる。 [0031] According to the third aspect of the present invention, the image reading device reads an image of the original illuminated by the original illumination device capable of illuminating the original with higher efficiency by the light emitted from the light source. Can be provided.
[0032] 本発明の第四の態様によれば、光源から放出される光でより高い効率で原稿を照 明することが可能な原稿照明装置によって照明された該原稿の画像を読み取る画像 読取装置を提供することができる。 [0032] According to the fourth aspect of the present invention, the image reading device reads an image of the original illuminated by the original illumination device capable of illuminating the original with higher efficiency by the light emitted from the light source. Can be provided.
図面の簡単な説明  Brief Description of Drawings
[0033] [図 1] (a)及び (b)は、それぞれ、一般的な画像読取装置の概略図及びその副走査 方向における画像読取装置の断面図である。  FIGS. 1A and 1B are a schematic view of a general image reading apparatus and a cross-sectional view of the image reading apparatus in the sub-scanning direction, respectively.
[図 2]画像読取装置における原稿の照明に関する問題点の を説明する図である  FIG. 2 is a diagram for explaining a problem relating to document illumination in the image reading apparatus.
[図 3]画像読取装置における原稿の照明に関する別の問題点を説明する図である。 FIG. 3 is a diagram for explaining another problem relating to illumination of a document in the image reading apparatus.
[図 4]複数の LEDで構成された光源及びその光源による照明を説明する図である。  FIG. 4 is a diagram illustrating a light source composed of a plurality of LEDs and illumination by the light source.
[図 5]本発明の第一の実施例による照明方法及び照明装置の例を説明する図である  FIG. 5 is a diagram for explaining an example of an illumination method and an illumination device according to the first embodiment of the present invention.
[図 6]本発明の第二の実施例による画像読取装置の例を説明する図である。 FIG. 6 is a diagram illustrating an example of an image reading apparatus according to a second embodiment of the present invention.
[図 7]本発明の第三の実施例による画像読取装置の例を説明する図である。  FIG. 7 is a diagram illustrating an example of an image reading apparatus according to a third embodiment of the present invention.
[図 8]本発明の第三の実施例による画像読取装置の変形例を説明する図である。  FIG. 8 is a diagram for explaining a modification of the image reading apparatus according to the third embodiment of the present invention.
[図 9]回転放物面鏡を用いて LEDから拡散する光束を平行光に変換する手段を説 明する図である。  FIG. 9 is a diagram illustrating a means for converting a light beam diffusing from an LED into parallel light using a rotating parabolic mirror.
[図 10]凸レンズを用いて LEDから拡散する光束を平行光に変換する手段を説明する 図である。 [図 11]本発明の第四の実施例による照明装置の一つの例を説明する図である。 FIG. 10 is a diagram for explaining means for converting a light beam diffused from an LED into parallel light using a convex lens. FIG. 11 is a diagram for explaining one example of a lighting device according to a fourth embodiment of the present invention.
[図 12]本発明の第四の実施例による照明装置の別の例を説明する図である。 FIG. 12 is a diagram for explaining another example of a lighting device according to the fourth embodiment of the present invention.
[図 13]本発明の第四の実施例による照明装置及び画像読取装置の一つの例を説明 する図である。 FIG. 13 is a diagram for explaining one example of an illumination device and an image reading device according to a fourth embodiment of the present invention.
[図 14]本発明の第四の実施例による照明装置及び画像読取装置の別の例を説明す る図である。  FIG. 14 is a diagram for explaining another example of the illumination device and the image reading device according to the fourth embodiment of the present invention.
園 15]本発明の第五の実施例による照明方法及び照明装置の例を説明する図であ 15] A diagram illustrating an example of a lighting method and a lighting device according to a fifth embodiment of the present invention.
[図 16]本発明の第六の実施例による照明方法及び画像読取装置の例を説明する図 である。 FIG. 16 is a diagram illustrating an example of an illumination method and an image reading apparatus according to a sixth embodiment of the present invention.
園 17]本発明の第七の実施例による照明方法及び照明装置の一つの例を説明する 図である。 17] It is a diagram for explaining one example of a lighting method and a lighting device according to a seventh embodiment of the present invention.
園 18]本発明の第七の実施例による照明装置の別の例を説明する図である。 18] It is a diagram for explaining another example of the lighting device according to the seventh embodiment of the present invention.
[図 19]本発明の第八の実施例による照明装置の例を説明する図である。 FIG. 19 is a diagram illustrating an example of a lighting device according to an eighth embodiment of the present invention.
[図 20]本発明の第九の実施例による画像読取装置の例を説明する図である。 FIG. 20 is a diagram illustrating an example of an image reading apparatus according to a ninth embodiment of the present invention.
[図 21]本発明の第十の実施例による画像読取装置の例を説明する図である。 FIG. 21 is a diagram illustrating an example of an image reading apparatus according to a tenth embodiment of the present invention.
[図 22]縮小光学系を用いた画像読取装置における撮像領域での照度分布及び CC D上での縮小光学系の相対明度の関係を説明する図である。 FIG. 22 is a diagram for explaining the relationship between the illuminance distribution in the imaging region and the relative brightness of the reduction optical system on the CCD in the image reading apparatus using the reduction optical system.
園 23]—次元 CCDに結像される画像の相対明度が一定となるような、撮像領域を照 明する複数の光源の配置間隔を決定する方法を説明する図である。 FIG. 23] is a diagram for explaining a method of determining the arrangement intervals of a plurality of light sources that illuminate an imaging region so that the relative brightness of an image formed on a two-dimensional CCD is constant.
園 24]—次元 CCDに結像される画像の相対明度が一定となるような、撮像対象領域 を照明する複数の光源の具体的な配置を説明する図である。 FIG. 24] is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate an imaging target region so that the relative brightness of an image formed on a two-dimensional CCD is constant.
[図 25]—定照度で照明された撮像対象領域を結像レンズによって一次元 CCD上に 結像される画像の相対明度の具体例、及び、一次元 CCD上に結像される画像の相 対明度が一定になるように撮像対象領域を照明する場合の目標照度分布（要求照 度分布）の具体例を示す図である。  [Fig.25] —A specific example of the relative brightness of an image that is imaged on a one-dimensional CCD by an imaging lens in an imaging target area illuminated at a constant illuminance, and the phase of the image that is imaged on the one-dimensional CCD. It is a figure which shows the specific example of target illuminance distribution (request | requirement illumination distribution) in the case of illuminating an imaging object area | region so that a brightness is constant.
園 26]照明対象領域 (撮像対象領域)を照明する目標相対照度に向けてシミュレ一 シヨンした結果を示す図である。 園 27]複数の光源の間隔を調整することによって、撮像領域を照明する光の照度分 布を 1/cos4 Θの特性に一致させる照明装置を実現するための概念図である。 園 28]—次元 CCDに結像される画像の相対明度が一定となるような、撮像対象領域 を照明する複数の光源の具体的な配置を説明する図である。 FIG. 26] A diagram showing a result of simulation toward a target relative illuminance for illuminating an illumination target area (imaging target area). 27] It is a conceptual diagram for realizing an illumination device that matches the illuminance distribution of the light that illuminates the imaging region with the 1 / cos 4 Θ characteristic by adjusting the interval between the plurality of light sources. FIG. 28] is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate an imaging target region so that the relative brightness of an image formed on a two-dimensional CCD is constant.
園 29]本発明の第 12の実際例における相対照度についてのシミュレーション結果を 示す図である。 FIG. 29] is a diagram showing a simulation result of relative illuminance in the twelfth practical example of the present invention.
園 30]複数の光源の各々力も撮像領域までの距離を調整することによって、撮像領 域を照明する光の照度分布を 1/cos4 Θの特性に一致させる照明装置を実現する ための概念図である。 30] Conceptual diagram for realizing an illuminating device that matches the illuminance distribution of the light that illuminates the imaging area with the 1 / cos 4 Θ characteristic by adjusting the distance to the imaging area for each of the light sources. It is.
園 31]光源力も放出される光の放射特性を変化させる方法の例を説明する図である 園 32]—次元 CCDに結像される画像の相対照度が一定となるような、撮像領域を照 明する複数の光源の配置の別の例を説明する図である。 Fig. 31] is a diagram for explaining an example of a method for changing the radiation characteristics of the light that is also emitted by the light source. Gaku 32] —illuminates the imaging area so that the relative illuminance of the image formed on the three-dimensional CCD is constant. It is a figure explaining another example of arrangement | positioning of the several light source to light.
園 33]複数の光源力も放出される光の放射特性を調整することによって、撮像領域を 照明する光の照度分布を 1/cos4 Θの特性に一致させる照明装置を実現するため の概念図である。 33] This is a conceptual diagram for realizing an illuminating device that matches the illuminance distribution of the light that illuminates the imaging area with the 1 / cos 4 Θ characteristic by adjusting the radiation characteristics of the light that is also emitted by multiple light sources. is there.
園 34]複数の光源の各々力も撮像領域までの距離を調整することによって、撮像領 域を照明する光の照度分布を 1/cos4 Θの特性に近似する照明装置を実現するた めの概念図である。 34] A concept for realizing an illuminator that approximates the illuminance distribution of the light that illuminates the imaging area to the 1 / cos 4 Θ characteristic by adjusting the distance to the imaging area for each of the light sources. FIG.
園 35]—次元 CCDに結像される画像の相対明度が一定となるような、撮像対象領域 を照明する複数の光源の具体的な配置を説明する図である。 [36] FIG. 35 is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate an imaging target region so that the relative brightness of an image formed on a three-dimensional CCD is constant.
園 36]複複数の光源の各々力も撮像領域までの距離の調整及び複数の光源力も放 出される光の放射特性の調整の両方によって、撮像領域を照明する光の照度分布 を 1/cos4 Θの特性に一致させる照明装置を実現するための概念図である。 36] The illuminance distribution of the light that illuminates the imaging area is adjusted to 1 / cos 4 Θ both by adjusting the power of each of the multiple light sources, adjusting the distance to the imaging area, and adjusting the radiation characteristics of the light emitted by the multiple light source forces. It is a conceptual diagram for implement | achieving the illuminating device matched with the characteristic of this.
園 37]—次元 CCDに結像される画像の相対明度が一定となるような、撮像対象領域 を照明する複数の光源の具体的な配置を説明する図である。 37] —A diagram illustrating a specific arrangement of a plurality of light sources that illuminate an imaging target region so that the relative brightness of an image formed on a three-dimensional CCD is constant.
園 38]本発明の第 16の実際例における相対照度と目標の照度分布との差分につい てのシミュレーション結果を示す図である。 [図 39]複数の光源力も放出される光の照明光軸の角度を調整することによって、撮 像領域を照明する光の照度分布を 1/cos4 Θの特性に一致させる照明装置を実現 するための概念図である。 [38] FIG. 38 is a diagram showing a simulation result on the difference between the relative illuminance and the target illuminance distribution in the sixteenth actual example of the invention. [Fig.39] By adjusting the angle of the illumination optical axis of light that is also emitted from multiple light sources, an illuminator that matches the illuminance distribution of the light that illuminates the imaging area with the 1 / cos 4 Θ characteristic is realized. It is a conceptual diagram for.
[図 40]凹シリンダレンズを用いて光源から仮想光源を形成することを説明する図であ  FIG. 40 is a diagram for explaining the formation of a virtual light source from a light source using a concave cylinder lens.
[図 41]本発明の実施形態及び実施例に用いることができる光学部品を説明する図で ある。 FIG. 41 is a diagram for explaining an optical component that can be used in the embodiments and examples of the present invention.
[図 42]本発明の実施形態及び実施例に用いることができる光学部品を説明する図で ある。  FIG. 42 is a diagram illustrating an optical component that can be used in the embodiment and examples of the present invention.
符号の説明  Explanation of symbols
[0034] 1·· 'LED (又は LEDチップ）、 2a…回転放物面鏡、 2b…回転楕円面鏡、 2c…凸レ ンズ、 2d…放物面鏡、 3…照明レンズ、 4a…集束レンズ、 4b, 4bl, 4b2…集束ミラ 一、 5, 5a, 5b-—filJ面鏡、 6, 6a, 6b…折り返しミラー、 7···プリズム、 8···回シ!;ンダ、 10···照明ユニット、 11···第一走行体、 11a…走行体、 12···変向ミラー、 13···コンタ タトガラス、 14···結像レンズ、 15···—次元撮像素子、 16···読み取りユニット、 17a, 1 7b, 17c…折り返しミラー、 18…カラーフィルター、 21…電極、 22…リード線、 23··· 透明樹脂、 24…フードレンズ、 25…ベース、 31…感光体、 32…紙送りローラ、 33··· シート原稿、 Sx…主走査方向、 Sy…副操作方向、 ΑχΙ···照明光軸、 AxR…読取光 軸、 Ai…撮像領域，照明領域，照明対象領域、 Di…照度分布、 VI···長手方向、 Vs …短手方向、 VLS…虚光源，仮想光源。  [0034] 1 ... LED (or LED chip), 2a ... rotating parabolic mirror, 2b ... rotating ellipsoidal mirror, 2c ... convex lens, 2d ... parabolic mirror, 3 ... illumination lens, 4a ... focusing Lens, 4b, 4bl, 4b2 ... Focus mirror 1, 5, 5a, 5b--filJ face mirror, 6, 6a, 6b ... Folding mirror, 7 ... Prism, ... ··· Illumination unit, ··· 1st traveling body, 11a ... traveling body, 12 ··· turning mirror, 13 ··· contact glass, 14 ··· imaging lens, 15 ··· —dimensional imaging device 16 ... Reading unit 17a, 1 7b, 17c ... Folding mirror 18 ... Color filter 21 ... Electrode 22 ... Lead wire 23 ... Transparent resin 24 ... Food lens 25 ... Base 31 ... Photoreceptor, 32 ... Paper feed roller, 33 ... Sheet original, Sx ... Main scanning direction, Sy ... Sub-operation direction, ΑχΙ ... Illumination optical axis, AxR ... Reading optical axis, Ai ... Imaging area, Illumination area, Illumination target area, Di ... Illuminance distribution VI · · · longitudinally, Vs ... lateral direction, VLS ... virtual source, the virtual light source.
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0035] 次に、本発明の実施の形態を図面と共に説明する。 Next, an embodiment of the present invention will be described with reference to the drawings.
[0036] 本発明の実施形態は、原稿面照明方法、（原稿）照明装置、及び、それを用いた画 像読取装置に関する。本発明の実施形態は、例えば、本発明の実施形態は、複写 機又はファクシミリの原稿面を照射する照明方法及び照明装置、デジタル PPC (普 通紙複写機)などに搭載される固体撮像素子、結像レンズ、及び照明装置を搭載し た（フィルムスキャナ及びノヽンディスキャナのような）画像読取装置とそのための照明 装置に関する。 [0037] 本発明の第一の実施形態は、光源からの光によって照明された原稿面からの散乱 光を結像レンズによって感光体又は撮像素子に結像させて、原稿面の画像における 画像形成対象位置での一次元画像を形成し、原稿面の画像形成対象位置を、一次 元画像に沿った方向（主走査方向）と直角な方向（副走査方向）に順次移動させるこ とによって、原稿面の画像における二次元の画像を形成する、画像形成装置用の原 稿面照明方法において、少なくとも一次元画像に沿った方向（主走査方向）に対応 する方向に複数の光源を配置し、複数の光源から放出される光の光束を、原稿面の 一次元画像に沿った方向において、隣接する光源の間隔の二倍以上の範囲に拡散 させることを特徴とする画像形成装置用の原稿面照明方法である。 Embodiments of the present invention relate to a document surface illumination method, a (document) illumination device, and an image reading device using the same. Embodiments of the present invention include, for example, an illumination method and an illumination device for illuminating a document surface of a copying machine or a facsimile, a solid-state imaging device mounted on a digital PPC (common paper copying machine), etc. The present invention relates to an image reading apparatus (such as a film scanner and a non-day scanner) equipped with an imaging lens and an illumination device, and an illumination device for the image reading device. [0037] In the first embodiment of the present invention, scattered light from a document surface illuminated by light from a light source is imaged on a photoconductor or an image sensor by an imaging lens to form an image on an image on the document surface. A one-dimensional image is formed at the target position, and the image formation target position on the document surface is sequentially moved in a direction (sub-scanning direction) perpendicular to the direction along the one-dimensional image (main scanning direction). In a document surface illumination method for an image forming apparatus that forms a two-dimensional image of a surface image, a plurality of light sources are arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction). Illuminating the document surface for an image forming apparatus, wherein the light beam emitted from the light source is diffused in a direction along the one-dimensional image of the document surface in a range of at least twice the interval between adjacent light sources. Is the method.
[0038] 本発明の第二の実施形態は、光源からの光によって照明された原稿面からの散乱 光を結像レンズによって感光体又は撮像素子に結像させて、原稿面の画像における 画像形成対象位置での一次元画像を形成し、原稿面の画像形成対象位置を、一次 元画像に沿った方向（主走査方向）と直角な方向（副走査方向）に順次移動させるこ とによって、原稿面の画像における二次元の画像を形成する、画像形成装置用の原 稿面照明方法において、少なくとも一次元画像に沿った方向（主走査方向）に対応 する方向に複数の光源を配置し、複数の光源から放出される光の光束を、原稿面の 一次元画像に沿った方向において、隣接する光源の間隔の二倍以上の範囲に拡散 させ、複数の光源から放出される光の光束の少なくとも一部を、原稿面の一次元画 像に沿った方向（主走査方向）と直角な方向（副走査方向）において、概略集束させ ることを特徴とする画像形成装置用の原稿面照明方法である。  In the second embodiment of the present invention, the scattered light from the document surface illuminated by the light from the light source is imaged on the photosensitive member or the image sensor by the imaging lens, thereby forming an image on the image on the document surface. A one-dimensional image is formed at the target position, and the image formation target position on the document surface is sequentially moved in a direction (sub-scanning direction) perpendicular to the direction along the one-dimensional image (main scanning direction). In a document surface illumination method for an image forming apparatus that forms a two-dimensional image of a surface image, a plurality of light sources are arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction). The light flux emitted from the two light sources is diffused in a direction along the one-dimensional image of the document surface to a range of at least twice the interval between adjacent light sources, and at least the light flux emitted from the plurality of light sources Part of the original In Motoe direction along the image (main scanning direction) perpendicular to direction (sub-scanning direction), an original surface illumination method for an image forming apparatus according to claim Rukoto is schematically focusing.
[0039] 本発明の第三の実施形態は、発光手段、発光手段から発生した光によって照明さ れた原稿面からの散乱光を撮像素子に結像させる結像手段、原稿面の画像におけ る一次元画像を読み取る読取手段、及び、一次元画像に沿った方向（主走査方向） と直角な方向（副走査方向）に読取手段の読み取り位置を順次移動させる移動手段 を用いて原稿面の画像を読み取る、画像読取装置用の照明装置において、少なくと も一次元画像に沿った方向（主走査方向）に対応する方向に配置された複数の発光 手段、及び、複数の発光手段から発生した光の光束を、原稿面の一次元画像に沿つ た方向において、隣接する発光手段の間隔の二倍以上の範囲に拡散させる光拡散 手段を有することを特徴とする画像読取装置用の照明装置である。 In the third embodiment of the present invention, the light emitting means, the imaging means for forming an image on the image pickup device from the scattered light from the original surface illuminated by the light generated from the light emitting means, and the image on the original surface are used. Using a reading means for reading a one-dimensional image and a moving means for sequentially moving the reading position of the reading means in a direction (sub-scanning direction) perpendicular to the direction (main scanning direction) along the one-dimensional image. In an illumination device for an image reading apparatus that reads an image, the light emitted from a plurality of light emitting means and a plurality of light emitting means arranged at least in a direction corresponding to a direction along the one-dimensional image (main scanning direction). Light diffusion that diffuses the light flux in a direction along the one-dimensional image of the document surface in a range that is at least twice the interval between adjacent light-emitting means It is an illuminating device for image reading apparatuses characterized by having a means.
[0040] 本発明の第三の実施形態において、好ましくは、少なくとも一次元画像に沿った方 向（主走査方向）に対応する方向に配置された複数の発光手段を挟むように、一対 の反射鏡が、平行に配置される。 [0040] In the third embodiment of the present invention, preferably, a pair of reflections is provided so as to sandwich a plurality of light emitting means arranged at least in a direction corresponding to a direction along the one-dimensional image (main scanning direction). Mirrors are arranged in parallel.
[0041] 本発明の第三の実施形態において、好ましくは、光拡散手段は、シリンダレンズ (又
Figure imgf000014_0001
[0041] In the third embodiment of the present invention, preferably, the light diffusion means is a cylinder lens (or
Figure imgf000014_0001
[0042] 本発明の第三の実施形態において、好ましくは、複数の発光手段の各々における 光源の位置が焦点の位置である放物面鏡力 複数の発光手段の各々に対応するよ うに配置される。  [0042] In the third embodiment of the present invention, it is preferable that the position of the light source in each of the plurality of light emitting units is arranged so as to correspond to each of the plurality of light emitting units. The
[0043] 本発明の第三の実施形態において、好ましくは、複数の発光手段の各々における 光源の位置が一つの焦点の位置である楕円面鏡が、複数の発光手段の各々に対応 するように配置される。  [0043] In the third embodiment of the present invention, preferably, an ellipsoidal mirror in which the position of the light source in each of the plurality of light emitting means is the position of one focal point corresponds to each of the plurality of light emitting means. Be placed.
[0044] 本発明の第三の実施形態において、好ましくは、複数の発光手段の各々に対応す る凸レンズが配置される。  [0044] In the third embodiment of the present invention, preferably, a convex lens corresponding to each of the plurality of light emitting means is arranged.
[0045] 本発明の第三の実施形態において、好ましくは、複数の光源から放出される光の 光束の少なくとも一部を、原稿面の一次元画像に沿った方向（主走査方向）と直角な 方向（副走査方向）にお!/、て、概略集束させる光集束手段が配置される。 [0045] In the third embodiment of the present invention, preferably, at least a part of light beams emitted from a plurality of light sources are perpendicular to a direction along the one-dimensional image of the document surface (main scanning direction). In the direction (sub-scanning direction), light focusing means for roughly focusing is arranged.
[0046] 本発明の第三の実施形態において、好ましくは、発光手段は、発光ダイオード (LE[0046] In the third embodiment of the present invention, preferably, the light emitting means is a light emitting diode (LE).
D)である。 D).
[0047] 本発明の第四の実施形態は、光源からの光によって照明された原稿面からの散乱 光を結像レンズによって撮像素子に結像させて、原稿面の画像における画像読み取 り位置での一次元画像を読み取り、原稿面の画像読み取り位置を、一次元画像を読 み取る方向（主走査方向）と直角な方向（副走査方向）に順次移動させると共に一次 元画像の読み取りを繰り返すことによって、原稿面の画像における二次元の画像を 読み取る、画像読取装置において、少なくとも一次元画像に沿った方向（主走査方 向）に対応する方向に配置された複数の光源、及び、複数の光源に対応するように 配置され、複数の光源から放出される光の光束を、原稿面の一次元画像に沿った方 向において、隣接する光源の間隔の二倍以上の範囲に拡散させ、且つ、原稿面に 重畳させる複数のレンズ (照明レンズ)を有することを特徴とする画像読取装置である In the fourth embodiment of the present invention, the scattered light from the original surface illuminated by the light from the light source is imaged on the image sensor by the imaging lens, and the image reading position in the image on the original surface is obtained. One-dimensional images, and sequentially moving the image reading position on the document surface in a direction (sub-scanning direction) perpendicular to the direction in which the one-dimensional image is read (main scanning direction). A plurality of light sources arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction) and a plurality of light sources. The light flux emitted from a plurality of light sources is diffused in a range along the one-dimensional image of the document surface in a range more than twice the interval between adjacent light sources, and To draft surface An image reading apparatus having a plurality of lenses (illumination lenses) to be superimposed
[0048] 本発明の第五の実施形態は、光源からの光によって照明された原稿面からの散乱 光を結像レンズによって撮像素子に結像させて、原稿面の画像における画像形成対 象位置での一次元画像を読み取り、原稿面の画像形成対象位置を、一次元画像を 読み取る方向（主走査方向）と直角な方向（副走査方向）に順次移動させると共に一 次元画像の読み取りを繰り返すことによって、原稿面の画像における二次元の画像 を読み取る、画像読取装置において、本発明の第三の実施形態である照明装置を 有することを特徴とする画像読取装置である。 [0048] In the fifth embodiment of the present invention, scattered light from a document surface illuminated by light from a light source is imaged on an image sensor by an imaging lens, and an image formation target position in an image on the document surface. The one-dimensional image is read and the image formation target position on the document surface is sequentially moved in the direction (sub-scanning direction) perpendicular to the direction of reading the one-dimensional image (main scanning direction) and the reading of the one-dimensional image is repeated. Thus, the image reading apparatus for reading a two-dimensional image in the image on the document surface includes the illumination device according to the third embodiment of the present invention.
[0049] 本発明の第六の実施形態は、光源からの光によって照明された原稿面からの散乱 光を結像レンズによって撮像素子に結像させて、原稿面の画像における画像形成対 象位置での一次元画像を読み取り、原稿面の画像形成対象位置を、一次元画像を 読み取る方向（主走査方向）と直角な方向（副走査方向）に順次移動させると共に一 次元画像の読み取りを繰り返すことによって、原稿面の画像における二次元の画像 を読み取る、画像読取装置において、少なくとも一次元画像に沿った方向（主走査 方向）に対応する方向に配置された複数の光源、及び、複数の光源に対応するよう に配置され、複数の光源から放出される光の光束を、原稿面の一次元画像に沿った 方向において、隣接する光源の間隔以上の範囲に拡散させ、且つ、原稿面に重畳さ せる複数のレンズ (照明レンズ)を有することを特徴とする画像読取装置において、複 数の光源は、画像形成対象位置での原稿面における原稿面を照明する光の照度の 分布特性が、撮像素子に結像レンズによって結像される画像の明度の分布特性と概 略逆であるように、配置されることを特徴とする画像読取装置である。  In the sixth embodiment of the present invention, the scattered light from the original surface illuminated by the light from the light source is imaged on the image sensor by the imaging lens, and the image formation target position in the image on the original surface The one-dimensional image is read and the image formation target position on the document surface is sequentially moved in the direction (sub-scanning direction) perpendicular to the direction of reading the one-dimensional image (main scanning direction) and the reading of the one-dimensional image is repeated. In the image reading apparatus that reads a two-dimensional image in the image on the document surface, a plurality of light sources arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction), and a plurality of light sources The light beams emitted from a plurality of light sources are arranged so as to correspond to each other in a direction along the one-dimensional image of the document surface, and are diffused to a range that is equal to or larger than the interval between adjacent light sources. In the image reading apparatus characterized by having a plurality of lenses to be superimposed (illumination lenses), the plurality of light sources has an illuminance distribution characteristic of light that illuminates the document surface at the document formation target position. The image reading apparatus is arranged so as to be approximately opposite to a lightness distribution characteristic of an image formed on an imaging element by an imaging lens.
[0050] 本発明の第六の実施形態である画像読取装置又は本発明の第六の実施形態であ る画像読取装置用の照明装置において、好ましくは、複数の光源の間の間隔は、画 像形成対象位置での原稿面における原稿面を照明する光の照度の分布特性が、撮 像素子に結像レンズによって結像される画像の明度の分布特性と概略逆であるよう に、設定される。  [0050] In the image reading apparatus according to the sixth embodiment of the present invention or the illumination apparatus for the image reading apparatus according to the sixth embodiment of the present invention, preferably, the interval between the plurality of light sources is set to be an image. The distribution characteristic of the illuminance of the light that illuminates the document surface at the image formation target position is set so that it is roughly opposite to the lightness distribution characteristic of the image formed by the imaging lens on the imaging element. The
[0051] 本発明の第六の実施形態である画像読取装置又は本発明の第六の実施形態であ る画像読取装置用の照明装置において、好ましくは、原稿面からの複数の光源まで の距離は、画像形成対象位置での原稿面における原稿面を照明する光の照度の分 布特性が、撮像素子に結像レンズによって結像される画像の明度の分布特性と概略 逆であるように、設定される。 [0051] An image reading apparatus according to a sixth embodiment of the present invention or a sixth embodiment of the present invention. Preferably, the distance from the document surface to the plurality of light sources is such that the distribution characteristic of the illuminance of the light that illuminates the document surface at the image formation target position is the image sensor. Is set so as to be approximately opposite to the brightness distribution characteristic of the image formed by the imaging lens.
[0052] 本発明の第六の実施形態である画像読取装置又は本発明の第六の実施形態であ る画像読取装置用の照明装置において、好ましくは、複数の光源から放出される光 の光束の発散角は、画像形成対象位置での原稿面における原稿面を照明する光の 照度の分布特性が、撮像素子に結像レンズによって結像される画像の明度の分布 特性と概略逆であるように、設定される。  [0052] In the image reading apparatus according to the sixth embodiment of the present invention or the illuminating device for the image reading apparatus according to the sixth embodiment of the present invention, preferably, a light flux emitted from a plurality of light sources The divergence angle is such that the illuminance distribution characteristic of the light that illuminates the original surface at the image formation target position is roughly opposite to the lightness distribution characteristic of the image formed by the imaging lens on the image sensor. To be set.
[0053] 本発明の第六の実施形態である画像読取装置又は本発明の第六の実施形態であ る画像読取装置用の照明装置において、複数の光源の光軸の向きは、画像形成対 象位置での原稿面における原稿面を照明する光の照度の分布特性が、撮像素子に 結像レンズによって結像される画像の明度の分布特性と概略逆であるように、設定さ れる。  In the image reading apparatus according to the sixth embodiment of the present invention or the illuminating device for the image reading apparatus according to the sixth embodiment of the present invention, the directions of the optical axes of the plurality of light sources depend on the image forming pair. The distribution characteristic of the illuminance of the light that illuminates the document surface on the document surface at the elephant position is set so as to be approximately opposite to the distribution characteristic of the brightness of the image formed on the image sensor by the imaging lens.
[0054] なお、「画像読取装置用の照明装置」とは、画像読取装置に用いられる、少なくとも 一次元画像に沿った方向（主走査方向）に対応する方向に配置された複数の光源を 含むと共にそれら複数の光源力 の光によって原稿面を照明する照明装置を意味す  Note that the “illuminating device for the image reading device” includes a plurality of light sources arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction) used in the image reading device. And an illuminating device that illuminates the document surface with light from these multiple light sources.
[0055] また、本発明の第六の実施形態である画像読取装置又は本発明の第六の実施形 態である画像読取装置用の照明装置においては、複数の光源の間の間隔、原稿面 力、らの複数の光源までの距離、複数の光源から放出される光の光束の発散角、及び 、複数の光源の光軸の向きの少なくとも二つのものの組み合わせ（例えば、原稿面か らの複数の光源までの距離及び複数の光源力 放出される光の光束の発散角）を、 画像形成対象位置での原稿面における原稿面を照明する光の照度の分布特性が、 撮像素子に結像レンズによって結像される画像の明度の分布特性と概略逆であるよ うに、設定してもよい。 [0055] In the image reading apparatus according to the sixth embodiment of the present invention or the illumination device for the image reading apparatus according to the sixth embodiment of the present invention, the interval between a plurality of light sources, the document surface Combination of at least two of force, distance to a plurality of light sources, divergence angle of light beams emitted from the plurality of light sources, and direction of optical axes of the plurality of light sources (for example, a plurality from the document surface) The distance to the light source and the divergence angle of the luminous flux of the emitted light), and the distribution characteristics of the illuminance of the light that illuminates the document surface at the image formation target position. May be set so as to be roughly opposite to the lightness distribution characteristic of the image formed by.
[0056] なお、本発明の実施形態において、照明される対象としては、例えば、シート状の 原稿、並びに、本及びノートのような、複数のシート状の原稿が綴じられたブック原稿 1S 挙げられる。また、照射面は、ある面積を備えた面である。 Note that, in the embodiment of the present invention, as an object to be illuminated, for example, a sheet original and a book original in which a plurality of sheet originals such as a book and a notebook are bound. 1S. Further, the irradiated surface is a surface having a certain area.
[0057] 本発明の実施形態の一つによれば、少なくとも一次元画像に沿った方向（主走査 方向）に対応する方向に複数の光源（又は発光手段）を配置し、複数の光源から放 出される光の光束を、原稿面の一次元画像に沿った方向において、隣接する光源の 間隔の二倍以上の範囲に拡散させることによって、複数の光源を用いて、原稿面に おけるより広い領域を照明する場合であっても、複数の光源 (又は発光手段）の間に おける発光量の差を緩和するように、原稿面を照明することが可能となる。すなわち、 原稿面の照明された領域における照度むらの減少させるように、原稿面を照明するこ とが可能となる。よって、原稿面の一次元画像に沿った方向において、原稿面を、よ り均一に又はより高い効率で、照明することが可能となる。その結果、照明された原 稿面から高品質な画像を得ることが可能となる。 [0057] According to one embodiment of the present invention, a plurality of light sources (or light emitting means) are arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction), and emitted from the plurality of light sources. A wider area on the document surface using multiple light sources by diffusing the emitted light flux in the direction along the one-dimensional image of the document surface to a range that is at least twice the interval between adjacent light sources. Even when illuminating the document, it is possible to illuminate the document surface so as to alleviate the difference in the amount of light emission among a plurality of light sources (or light emitting means). In other words, it is possible to illuminate the document surface so as to reduce unevenness in illuminance in the illuminated area of the document surface. Therefore, it is possible to illuminate the document surface more uniformly or with higher efficiency in the direction along the one-dimensional image of the document surface. As a result, high-quality images can be obtained from the illuminated original document.
[0058] また、本発明の実施形態の一つによれば、複数の光源から放出される光の光束を 、原稿面の一次元画像に沿った方向（主走査方向）と直角な方向（副走査方向）にお いて、概略集束させることによって、原稿面を照明する効率を向上させることが可能と なる。その結果、原稿面を照明するために必要なエネルギーを低減することが可能と なる（省エネルギー）。 [0058] According to one embodiment of the present invention, a light beam emitted from a plurality of light sources is divided into a direction (sub scan direction) perpendicular to the direction along the one-dimensional image of the document surface (main scanning direction). By roughly focusing in the scanning direction), it is possible to improve the efficiency of illuminating the document surface. As a result, the energy required to illuminate the document surface can be reduced (energy saving).
[0059] さらに、本発明の実施形態の一つによれば、上記反射鏡、上記シリンダレンズ (又 はシリンドリカルレンズ）、上記放物面鏡、上記楕円面鏡、及び上記凸レンズを、ブラ スチック成型手段によって、得ること力 Sできるので、照明装置又は画像読取装置のコ ストを低減することが可能となる。  [0059] Furthermore, according to one embodiment of the present invention, the reflecting mirror, the cylinder lens (or cylindrical lens), the parabolic mirror, the elliptical mirror, and the convex lens are plastic molded. Since it is possible to obtain the force S by means, the cost of the illumination device or the image reading device can be reduced.
[0060] また、本発明の実施形態の一つによれば、光源に発光ダイオード（LED)を用いる と、光源を低い電圧の直流電源によって駆動することができるので、光源の点灯回路 を、非常に簡単に設けることが可能となる。その結果、照明装置又は画像読取装置 のコストを低減することが可能となる。  [0060] Also, according to one embodiment of the present invention, when a light emitting diode (LED) is used as a light source, the light source can be driven by a low-voltage DC power supply. Can be easily provided. As a result, the cost of the illumination device or the image reading device can be reduced.
[0061] さらに、本発明の実施形態の一つによれば、複数の光源は、画像形成対象位置で の原稿面における原稿面を照明する光の照度の分布特性が、撮像素子に結像レン ズによって結像される画像の明度の分布特性と概略逆であるように、配置されるので 、複数の光源から放出される光のうち原稿面を照明することなく遮断される又は捨て られる光の量を低減する又は無くすと共に撮像素子における結像レンズによって結 像される画像の明度分布をより均一にすることが可能となる。その結果、光源から放 出される光でより高い効率で原稿を照明することが可能なり、原稿面を照明するため に必要なエネルギーを低減することが可能となる（省エネルギー）。 Furthermore, according to one of the embodiments of the present invention, the plurality of light sources has an illuminance distribution characteristic of light that illuminates the document surface at the image forming target position so that the imaging element has an imaging lens. Since it is arranged so as to be roughly opposite to the brightness distribution characteristic of the image formed by the image, it is blocked or discarded without illuminating the original surface of the light emitted from the plurality of light sources. It is possible to reduce or eliminate the amount of light generated and to make the brightness distribution of the image formed by the imaging lens in the image sensor more uniform. As a result, it is possible to illuminate the document with higher efficiency with the light emitted from the light source, and it is possible to reduce the energy required to illuminate the document surface (energy saving).
[0062] また、本発明の実施形態の一つによれば、複数の光源の間の間隔は、画像形成対 象位置での原稿面における原稿面を照明する光の照度の分布特性が、撮像素子に 結像レンズによって結像される画像の明度の分布特性と概略逆であるように、設定さ れるので、複数の光源から放出される光のうち原稿面を照明することなく遮断される 又は捨てられる光の量を低減する又は無くすと共に撮像素子における結像レンズに よって結像される画像の照度分布をより均一にすることが可能となる。その結果、光 源から放出される光でより高い効率で原稿を照明することが可能なり、原稿面を照明 するために必要なエネルギーを低減することが可能となる（省エネルギー）。  Further, according to one embodiment of the present invention, the interval between the plurality of light sources is such that the distribution characteristic of the illuminance distribution of the light that illuminates the document surface on the document surface at the image formation target position is imaged. Since it is set so as to be roughly opposite to the lightness distribution characteristic of the image formed by the imaging lens on the element, it is blocked without illuminating the document surface among the light emitted from a plurality of light sources or It is possible to reduce or eliminate the amount of light thrown away and to make the illuminance distribution of the image formed by the imaging lens in the image sensor more uniform. As a result, it is possible to illuminate the document with higher efficiency by the light emitted from the light source, and it is possible to reduce the energy required to illuminate the document surface (energy saving).
[0063] また、本発明の実施形態の一つによれば、原稿面からの複数の光源までの距離は 、画像形成対象位置での原稿面における原稿面を照明する光の照度の分布特性が 、撮像素子に結像レンズによって結像される画像の明度の分布特性と概略逆である ように、設定されるので、複数の光源から放出される光のうち原稿面を照明することな く遮断される又は捨てられる光の量を低減する又は無くすと共に撮像素子における 結像レンズによって結像される画像の照度分布をより均一にすることが可能となる。 その結果、光源から放出される光でより高い効率で原稿を照明することが可能なり、 原稿面を照明するために必要なエネルギーを低減することが可能となる（省エネルギ 一)。  Further, according to one of the embodiments of the present invention, the distance from the document surface to the plurality of light sources is the distribution characteristic of the illuminance of light that illuminates the document surface on the document surface at the image formation target position. Since it is set to be roughly opposite to the brightness distribution characteristics of the image formed by the imaging lens on the image sensor, the light emitted from multiple light sources is blocked without illuminating the document surface. It is possible to reduce or eliminate the amount of light emitted or discarded and to make the illuminance distribution of the image formed by the imaging lens in the image sensor more uniform. As a result, it is possible to illuminate the document with higher efficiency with the light emitted from the light source, and it is possible to reduce the energy required to illuminate the document surface (energy saving).
[0064] また、本発明の実施形態の一つによれば、複数の光源から放出される光の光束の 発散角は、画像形成対象位置での原稿面における原稿面を照明する光の照度の分 布特性が、撮像素子に結像レンズによって結像される画像の明度の分布特性と概略 逆であるように、設定されるので、複数の光源から放出される光のうち原稿面を照明 することなく遮断される又は捨てられる光の量を低減する又は無くすと共に撮像素子 における結像レンズによって結像される画像の照度分布をより均一にすることが可能 となる。その結果、光源から放出される光でより高い効率で原稿を照明することが可 能なり、原稿面を照明するために必要なエネルギーを低減することが可能となる (省 エネルギー）。 [0064] According to one of the embodiments of the present invention, the divergence angle of light beams emitted from a plurality of light sources is the illuminance of light that illuminates the document surface at the image formation target position. Since the distribution characteristics are set so as to be roughly opposite to the distribution characteristics of the brightness of the image formed by the imaging lens on the image sensor, the original surface of the light emitted from the plurality of light sources is illuminated. It is possible to reduce or eliminate the amount of light that is interrupted or discarded without making it possible to make the illuminance distribution of the image formed by the imaging lens in the image sensor more uniform. As a result, it is possible to illuminate the document with higher efficiency by the light emitted from the light source. As a result, the energy required to illuminate the original surface can be reduced (energy saving).
[0065] また、本発明の実施形態の一つによれば、複数の光源の光軸の向きは、画像形成 対象位置での原稿面における原稿面を照明する光の照度の分布特性が、撮像素子 に結像レンズによって結像される画像の明度の分布特性と概略逆であるように、設定 されるので、複数の光源から放出される光のうち原稿面を照明することなく遮断される 又は捨てられる光の量を低減する又は無くすと共に撮像素子における結像レンズに よって結像される画像の照度分布をより均一にすることが可能となる。その結果、光 源から放出される光でより高い効率で原稿を照明することが可能なり、原稿面を照明 するために必要なエネルギーを低減することが可能となる（省エネルギー）。  Further, according to one of the embodiments of the present invention, the direction of the optical axis of the plurality of light sources is determined by the distribution characteristics of the illuminance of the light that illuminates the document surface at the image formation target position. Since it is set so as to be roughly opposite to the brightness distribution characteristic of the image formed on the element by the imaging lens, it is blocked without illuminating the document surface among the light emitted from the plurality of light sources or It is possible to reduce or eliminate the amount of light thrown away and to make the illuminance distribution of the image formed by the imaging lens in the image sensor more uniform. As a result, it is possible to illuminate the document with higher efficiency by the light emitted from the light source, and it is possible to reduce the energy required to illuminate the document surface (energy saving).
[0066] なお、本発明の実施形態の一つによれば、複数の光源の間の間隔、原稿面からの 複数の光源までの距離、複数の光源から放出される光の光束の発散角、及び、複数 の光源の光軸の向きの少なくとも二つのものの組み合わせ（例えば、原稿面からの複 数の光源までの距離及び複数の光源から放出される光の光束の発散角）を、画像形 成対象位置での原稿面における原稿面を照明する光の照度の分布特性が、撮像素 子に結像レンズによって結像される画像の明度の分布特性と概略逆であるように、設 定することによつても、複数の光源から放出される光のうち原稿面を照明することなく 遮断される又は捨てられる光の量を低減する又は無くすと共に撮像素子における結 像レンズによって結像される画像の照度分布をより均一にすることが可能となる。その 結果、光源から放出される光でより高い効率で原稿を照明することが可能なり、原稿 面を照明するために必要なエネルギーを低減することが可能となる（省エネルギー）。  [0066] According to one embodiment of the present invention, the distance between the plurality of light sources, the distance from the document surface to the plurality of light sources, the divergence angle of the light flux emitted from the plurality of light sources, And a combination of at least two of the directions of the optical axes of the plurality of light sources (for example, the distance from the document surface to the plurality of light sources and the divergence angles of the light beams emitted from the plurality of light sources). Set the illuminance distribution characteristics of the light that illuminates the document surface at the target position to be roughly opposite to the brightness distribution characteristics of the image formed by the imaging lens on the imaging element. Therefore, the amount of light that is blocked or discarded without illuminating the document surface among the light emitted from a plurality of light sources is reduced or eliminated, and the image formed by the imaging lens in the image sensor is reduced. Make the illumination distribution more uniform It can become. As a result, it is possible to illuminate the document with higher efficiency by the light emitted from the light source, and it is possible to reduce the energy required to illuminate the document surface (energy saving).
[0067] [実施例]  [0067] [Example]
次に、本発明の実施形態に従った実施例を説明する。本発明の実施形態による照 明方法及び照明装置は、従来の（原稿面の画像を直接感光体に投影して感光体に 潜像を形成し、黒色トナー又はカラートナーによって潜像を現像して、可視画像を得 る）アナログ複写機にも使用することできる力 S、本発明の実施例においては、ディジタ ノレ複写機又は一般にスキャナと呼ばれる画像読取装置に用いられる、照明方法及び 照明装置を説明することにする。 実施例 1 Next, examples according to the embodiment of the present invention will be described. The illumination method and the illumination device according to the embodiment of the present invention are designed to form a latent image on a photoconductor by directly projecting an image on a document surface onto the photoconductor, and developing the latent image with black toner or color toner. In this embodiment of the present invention, an illumination method and an illumination device used in an image reading apparatus generally called a digital printer or a scanner will be described. I will do it. Example 1
[0068] 図 5は、本発明の第一の実施例による照明方法及び照明装置の例を説明する図で ある。図 5 (a)は、本発明の第一の実施例による照明装置の例の上面図であり、図 5 ( b)は、本発明の第一の実施例による照明装置の例の正面図である。また、図 5 (c)は 、本発明の第一の実施例による照明方法の例によって得られる照明対象面 (撮像領 域）（Ai)上での主走査方向（Sx)の照度分布を示す図であり、図 5 (d)は、本発明の 第一の実施例による照明方法の例によって得られる照明対象面 (撮像領域）（Ai)上 での副走査方向の照度分布を示す図である。  FIG. 5 is a diagram for explaining an example of an illumination method and an illumination apparatus according to the first embodiment of the present invention. FIG. 5 (a) is a top view of the example of the lighting device according to the first embodiment of the present invention, and FIG. 5 (b) is a front view of the example of the lighting device according to the first embodiment of the present invention. is there. FIG. 5 (c) shows the illuminance distribution in the main scanning direction (Sx) on the illumination target surface (imaging area) (Ai) obtained by the example of the illumination method according to the first embodiment of the present invention. FIG. 5 (d) is a diagram showing the illuminance distribution in the sub-scanning direction on the illumination target surface (imaging area) (Ai) obtained by the example of the illumination method according to the first embodiment of the present invention. is there.
[0069] 図 5 (a)及び (b)に示すような、本発明の第一の実施例による照明装置は、図 1 (a) 及び (b)に示す従来の照明装置における照明ランプ及びリフレクタに対応する。  [0069] The illumination device according to the first embodiment of the present invention as shown in FIGS. 5 (a) and (b) is an illumination lamp and reflector in the conventional illumination device shown in FIGS. 1 (a) and (b). Corresponding to
[0070] まず、本発明の第一の実施例による照明装置の構成を説明する。  First, the configuration of the illumination device according to the first example of the present invention will be described.
[0071] 図 5の（a)及び (b)に示すように、発明の第一の実施例による照明装置は、複数の LED (l)、複数の回転放物面鏡（2a)、照明レンズ (3)、集束レンズ (4a)、並びに、 側面鏡 A (5a)及び側面鏡 B (5b)を有する。  As shown in FIGS. 5 (a) and 5 (b), the illumination device according to the first embodiment of the invention includes a plurality of LEDs (1), a plurality of rotary parabolic mirrors (2a), and an illumination lens. (3) It has a focusing lens (4a) and side mirror A (5a) and side mirror B (5b).
[0072] 複数の LED (1)の各々は、発光ダイオードのチップであって、光源として用いられ る。本発明の第一の実施例の照明装置においては、 n個の LED (l) (Ll〜Ln)が、 主走査方向（Sx)に等間隔に配置されて!/、る。  Each of the plurality of LEDs (1) is a light emitting diode chip and is used as a light source. In the illumination device of the first embodiment of the present invention, n LEDs (l) (Ll to Ln) are arranged at equal intervals in the main scanning direction (Sx).
[0073] 複数の回転放物面鏡（2a)は、それぞれ、複数の LED (1)に対応して配置され、回 転放物面鏡（2a)の焦点位置に LED (1)の発光面を配置することによって、 LED力、 ら拡散する光の大部分を平行光に変換する。複数の回転放物面鏡（2a)は、 LED (1 )の発光面から LED (1)の前面側に 180° の角度で拡散する光束を集束する、第一 の集束手段として用いられる。  [0073] Each of the plurality of rotating parabolic mirrors (2a) is arranged corresponding to the plurality of LEDs (1), and the light emitting surface of the LED (1) is located at the focal position of the rotating parabolic mirror (2a). By arranging the LED power, most of the diffused light is converted into parallel light. The plurality of rotary paraboloid mirrors (2a) are used as a first focusing means for focusing the luminous flux diffusing at an angle of 180 ° from the light emitting surface of the LED (1) to the front side of the LED (1).
[0074] 照明レンズ (3)は、本発明の第一の実施例の照明装置においては、シリンダレンズ アレイである。照明レンズ (3)は、回転放物面鏡（2a)から射出される平行光の光束を 主走査方向（Sx)に拡散させ、照明レンズ (3)によって拡散させられた光で、照明対 象面 (Ai) (撮像領域と同一部分を指すが、照明装置を説明するときは、撮像領域を 、照明対象面又は照明対象領域と称する）を照明する。ここで、照明レンズ (3)のシリ ンダレンズアレイを構成する個々のレンズは、完全に又は実質的に同一のシリンダレ ンズであり、各々のシリンダレンズの焦点距離を fとし、シリンダレンズの配列方向（主 走査方向（Sx) )における各々のシリンダレンズの幅を mとする。また、各々のシリンダ レンズの幅 mは、複数の LED ( l )における隣接する LED ( l )の間隔に等しい。そし て、シリンダレンズから照明対象面 (撮像領域）（Ai)までの距離を gとすると、シリンダ レンズの配列方向（主走査方向（Sx) )において、シリンダレンズを透過した光によつ て照明される照明対象面 (撮像領域）（Ai)上での照明範囲 Mは、 The illumination lens (3) is a cylinder lens array in the illumination device of the first embodiment of the present invention. The illumination lens (3) diffuses the parallel light beam emitted from the rotary paraboloid mirror (2a) in the main scanning direction (Sx) and is diffused by the illumination lens (3). The surface (Ai) (refers to the same part as the imaging region, but when the illumination device is described, the imaging region is referred to as an illumination target surface or an illumination target region) is illuminated. Here, the individual lenses constituting the cylinder lens array of the illumination lens (3) are completely or substantially the same cylinder lens. Where f is the focal length of each cylinder lens, and m is the width of each cylinder lens in the cylinder lens array direction (main scanning direction (Sx)). The width m of each cylinder lens is equal to the interval between adjacent LEDs (l) in the plurality of LEDs (l). When the distance from the cylinder lens to the illumination target surface (imaging area) (Ai) is g, illumination is performed by light transmitted through the cylinder lens in the cylinder lens arrangement direction (main scanning direction (Sx)). The illumination range M on the illumination target surface (imaging area) (Ai)
[0075] 國 f [0075] Country f
[0076] によって、表される。本発明の第一の実施例の照明装置においては、主走査方向（S X)において、各々のシリンダレンズの幅 m、すなわち、複数の LED (1)における隣接 する LED ( 1 )の間隔に対するシリンダレンズを透過した光によつて照明される照明対 象面（撮像領域）（Ai)上での照明範囲 Mの比（M/m)が、二倍以上である。一方、 シリンダレンズの配列方向（主走査方向（Sx) )と直角な方向（副走査方向（Sy) )にお いては、シリンダレンズは、平行平面板と等価であるので、回転放物面鏡（2a)力 射 出される平行光の光束を、平行光として透過させる。 [0076] In the illuminating device of the first embodiment of the present invention, in the main scanning direction (SX), the width m of each cylinder lens, that is, the cylinder lens with respect to the interval between adjacent LEDs (1) in the plurality of LEDs (1). The ratio (M / m) of the illumination range M on the illumination target surface (imaging area) (Ai) illuminated by the light that has passed through is more than twice. On the other hand, in the direction perpendicular to the arrangement direction of the cylinder lenses (main scanning direction (Sx)) (sub-scanning direction (Sy)), the cylinder lens is equivalent to a plane parallel plate, and therefore, a paraboloid mirror. (2a) Force-emitted parallel light flux is transmitted as parallel light.
[0077] なお、主走査方向（Sx)における照明対称面の長さを Kとすると、主走査方向（Sx) におけるシリンダレンズアレイの幅もまた Kであってもよい。また、主走査方向（Sx)に おけるシリンダレンズの幅は、主走査方向（Sx)における回転放物面鏡（2a)の幅と完 全に又は実質的に同一であることが好ましい。すなわち、  [0077] If the length of the illumination symmetry plane in the main scanning direction (Sx) is K, the width of the cylinder lens array in the main scanning direction (Sx) may also be K. The width of the cylinder lens in the main scanning direction (Sx) is preferably completely or substantially the same as the width of the paraboloid mirror (2a) in the main scanning direction (Sx). That is,
[0078] [数 2]  [0078] [Equation 2]
K  K
m =—  m = —
n  n
[0079] であること力 S好ましく、ここで、 nは、シリンダレンズアレイを構成するシリンダレンズの 数である。  [0079] The force S is preferable, where n is the number of cylinder lenses constituting the cylinder lens array.
[0080] 集束レンズ (4a)は、単体のシリンダレンズであって、照明レンズ（3)を透過した光を 、副走査方向（Sy)において、照明対象面（撮像領域） (Ai)に集束させるように設け られる。すなわち、回転放物面鏡（2a)から放出された平行光は、副走査方向（Sy) においては、照明レンズ (3)によって拡散させられず、集束レンズ (4)によって、照明 対象面（撮像領域）（Ai)にシャープに集束させられる。集束レンズ (4)は、主走査方 向（Sx)においては、平行平面板と等価であるので、照明レンズ（3)によって拡散さ せられた光は、集束レンズ (4)によって集束させられず、そのまま拡散する。なお、集 束レンズ (4)は、集束レンズと同様の機能を有する放物面鏡で容易に代用され得る。 [0080] The focusing lens (4a) is a single cylinder lens that focuses the light transmitted through the illumination lens (3) onto the illumination target surface (imaging area) (Ai) in the sub-scanning direction (Sy). It is provided as follows. That is, the parallel light emitted from the rotating parabolic mirror (2a) is transmitted in the sub-scanning direction (Sy) In this case, the light is not diffused by the illumination lens (3), but is sharply focused on the illumination target surface (imaging area) (Ai) by the focusing lens (4). Since the focusing lens (4) is equivalent to a plane-parallel plate in the main scanning direction (Sx), the light diffused by the illumination lens (3) is not focused by the focusing lens (4). , Diffuse as it is. The collecting lens (4) can be easily substituted with a parabolic mirror having the same function as the focusing lens.
[0081] 加えて、集束レンズ (4)は、本発明の第一の実施例の照明装置において、必ずしも 必要であるものではなぐ照明レンズ（3)を透過した光を、副走査方向（Sy)において 、平行光として照明対象面 (撮像領域）（Ai)に当ててもよい。また、集束レンズ (4)は 、照明対象面 (撮像領域）（Ai)側の位置に配置してもよぐ照明レンズ (3)側に配置 させてもよい。さらには、集束レンズ (4)を、照明レンズ (3)と一体に形成することも可 能である。この場合には、プラスチック成型の手段を用いることによって、照明装置に 用いられる部品点数を減少させることができる。  [0081] In addition, the focusing lens (4) transmits light transmitted through the illumination lens (3), which is not necessarily required, in the illumination device of the first embodiment of the present invention. In this case, it may be applied to the illumination target surface (imaging area) (Ai) as parallel light. Further, the focusing lens (4) may be arranged on the illumination lens (3) side or on the illumination target surface (imaging region) (Ai) side position. Furthermore, the focusing lens (4) can be formed integrally with the illumination lens (3). In this case, the number of parts used for the lighting device can be reduced by using plastic molding means.
[0082] 側面鏡 A(5a)及び側面鏡 B (5b)は、照明レンズ (3)のシリンダレンズアレイの両側 に配置したミラーである。側面鏡 A(5a)及び側面鏡 B (5b)は、 LED (l)から放出さ れる光を、より高い効率で照明対象面 (撮像領域）（Ai)に照射するために設けられる 。図 5においては、三個の LED (l) (Ll、 L2、及び L3)から放出された光が、側面鏡 A (5a)によって照明対象面（撮像領域）（Ai)へ反射させられ、同様に、三個の LED (1) (Ln— 2、 Ln— 1、及び Ln)から放出された光が、側面鏡 B (5b)によって照明対 象面（撮像領域）（Ai)へ反射させられる。このように、側面鏡 A (5a)及び側面鏡 B (5 b)は、これらの六個の LED (1)力 あた力、も照明装置の外側に配置されるかのように 、これらの六個の LED (1)からの光を反射させるので、照明対象面（撮像領域） (Ai) の端部においても照明対象面 (撮像領域）（Ai)の中央部と同じように、均一な照度分 布が得られる。 （なお、シリンダレンズアレイ力も照明対象面 (撮像領域）（Ai)まで側 面鏡を設けることが理想的である力 実際の画像読取装置においては、原稿台とし てのコンタクトガラスを回避して、側面鏡を設ける必要がある。その結果、照明対象面 (撮像領域）（Ai)の端部の照度が、照明対象面 (撮像領域）（Ai)の中央部の照度に 対比して、若干低下する。それに応じて、主走査方向（Sx)における照明装置の全体 の幅を、広げる必要がある力 側面鏡 A(5a)及び側面鏡 B (5b)を設けた場合におけ る照明装置の全体の幅の変動量は、側面鏡を用いない場合における照明装置の全 体の幅の変動量に対して極めてわずかなものである。 ) The side mirror A (5a) and the side mirror B (5b) are mirrors arranged on both sides of the cylinder lens array of the illumination lens (3). The side mirror A (5a) and the side mirror B (5b) are provided to irradiate the illumination target surface (imaging region) (Ai) with higher efficiency with the light emitted from the LED (l). In Fig. 5, the light emitted from the three LEDs (l) (Ll, L2, and L3) is reflected by the side mirror A (5a) to the illumination target surface (imaging area) (Ai). In addition, the light emitted from the three LEDs (1) (Ln-2, Ln-1 and Ln) is reflected by the side mirror B (5b) to the illumination target surface (imaging area) (Ai). . In this way, side mirror A (5a) and side mirror B (5 b) have their six LEDs (1) force as if they were also placed outside the lighting device. Since the light from the six LEDs (1) is reflected, the edge of the illumination target surface (imaging area) (Ai) is uniform as well as the center of the illumination target surface (imaging area) (Ai). Illuminance distribution is obtained. (Note that it is ideal to provide a side mirror to the illumination target surface (imaging area) (Ai) for the cylinder lens array force. In an actual image reading device, avoid contact glass as a document table. As a result, the illuminance at the end of the illumination target surface (imaging area) (Ai) is slightly lower than the illuminance at the center of the illumination target surface (imaging area) (Ai). Accordingly, when the side mirror A (5a) and side mirror B (5b) are provided, it is necessary to increase the overall width of the illuminating device in the main scanning direction (Sx). The amount of variation in the overall width of the lighting device is very small compared to the amount of variation in the overall width of the lighting device when the side mirror is not used. )
次に、本発明の第一の実施例による照明装置を用いた、本発明の第一の実施例に よる照明方法を説明する。  Next, an illumination method according to the first embodiment of the present invention using the illumination device according to the first embodiment of the present invention will be described.
[0083] 図 5 (a)及び（c)に示すように、主走査方向（Sx)にお!/、て、複数の LED (1)の一つ  [0083] As shown in FIGS. 5 (a) and 5 (c), one of a plurality of LEDs (1) in the main scanning direction (Sx)!
(L4)から放出された光は、 L4に対応する回転放物面鏡（2a)によって反射され、概 略平行光として射出される。 L4に対応する回転放物面鏡（2a)から射出された光は、 L4に対応する、照明レンズ (3)を構成するシリンダレンズに入射する。そのシリンダレ ンズを透過した光は、シリンダレンズの焦点距離 fの位置で一旦集束させられる力 シ リンダレンズの焦点距離 fを超える距離では、集束レンズ (4)の有無にかかわらず、拡 散する。このようにして主走査方向（Sx)においては、 LED (1)の L4から放出された 光の光束の幅が、シリンダレンズの幅の大きさ m、すなわち、相互に隣接する LED (1 )の間隔の大きさから照明対象面 (撮像領域）（Ai)で Mまで広がり、照明対象面 (撮 像領域）（Ai)が照射される。ここで、 LED (1)の一つ L4に対応するシリンダレンズの 主点から照明対象面 (撮像領域）（Ai)までの距離を gとすると、主走査方向（Sx)に おける LED (l)の一つ L4から放出された光の光束の幅の拡大率 Q ( = M/m)は、  The light emitted from (L4) is reflected by the rotating parabolic mirror (2a) corresponding to L4 and is emitted as substantially parallel light. The light emitted from the rotary parabolic mirror (2a) corresponding to L4 is incident on the cylinder lens constituting the illumination lens (3) corresponding to L4. The light that has passed through the cylinder lens is diffused regardless of the presence of the focusing lens (4) at a distance that exceeds the focal length f of the force cylinder lens that is once focused at the focal length f of the cylinder lens. Thus, in the main scanning direction (Sx), the width of the light beam emitted from the L4 of the LED (1) is equal to the width m of the cylinder lens, that is, the adjacent LEDs (1). It spreads from the size of the interval to M on the illumination target surface (imaging area) (Ai), and the illumination target surface (imaging area) (Ai) is irradiated. Here, when the distance from the principal point of the cylinder lens corresponding to L4, one of the LEDs (1), to the illumination target surface (imaging area) (Ai) is g, LED (l) in the main scanning direction (Sx) The width expansion factor Q (= M / m) of the luminous flux of light emitted from L4 is
[0084] 園  [0084] Garden
Q _ {g - f) Q _ (g-f)
一 f  One f
[0085] によって、表される。本発明の第一の実施例による照明方法においては、主走査方 向（Sx)における LED (1)の一つから放出された光の光束の幅の拡大率 Q、すなわ ち、相互に隣接する LED (1)の間隔の大きさに対する照明対象面 (撮像領域）（Ai) での光束の幅 Mの比は、二倍以上である。なお、図 5においては、 Qは、約 6. 5程度 である。 [0085] In the illumination method according to the first embodiment of the present invention, the expansion factor Q of the width of the luminous flux of light emitted from one of the LEDs (1) in the main scanning direction (Sx), that is, adjacent to each other. The ratio of the luminous flux width M on the illumination target surface (imaging area) (Ai) to the size of the LED (1) interval is more than twice. In Fig. 5, Q is about 6.5.
[0086] このとき、 LED (1)の L4から放出された光のみに起因する、照明対象面（撮像領域 ) (Ai)上での照度分布は、図 5 (c)における太線で示すようなもの（Each— Di)であ る。すなわち、 LED (1)の L4及び L4に対応する回転放物面鏡（2a)の中心を通過す る軸（光軸）上における照度がピークであり、且つ、光軸から離れるに従って、 L4から 放出された光に起因する照度は低下する。その結果、 LED (1)の L4から放出された 光のみに起因する、照明対象面 (撮像領域）（Ai)上での照度分布は、照明対象面（ 撮像領域） (Ai)上の位置によって大きく変動する照度分布を与える。 [0086] At this time, the illuminance distribution on the illumination target surface (imaging region) (Ai) due to only the light emitted from L4 of the LED (1) is as shown by the bold line in FIG. 5 (c). Things (Each-Di). That is, the illuminance on the axis (optical axis) passing through the center of the rotating paraboloid mirror (2a) corresponding to L4 and L4 of LED (1) is a peak, and from L4 as it goes away from the optical axis. The illuminance due to the emitted light decreases. As a result, the illuminance distribution on the illumination target surface (imaging area) (Ai) due to only the light emitted from L4 of the LED (1) depends on the position on the illumination target surface (imaging area) (Ai). Gives a highly variable illuminance distribution.
[0087] ところ力 LED (1)の L4に隣接する LED (1)の L5から放出される光は、照明対象 面（撮像領域）（Ai)上で、 LED (1)の L4から放出される光に起因する照明対象面（ 撮像領域） (Ai)上での照度分布のピークの位置から主走査方向（Sx)に mだけ変位 したピークを有する同様の照度分布を与える。また、 1^^ (1)のし6〜し1の各々から 放出される光も同様の照度分布 (Di)で照明対象面 (撮像領域）（Ai)を照明する。こ こで、照明対象面（撮像領域）（Ai)上において、 LED (1)の L4の光軸上における光 は、 LED (1)の L1から放出された、より少量の光、 LED (1)の L2から放出された、中 間の量の光、 LED (2)の L3から放出された、より多量の光を含む。また、ここで、照 明対象面（撮像領域）（Ai)上において、 LED (1)の L4の光軸上における光は、 LE D (l)の L3からの放出された光の量と同程度の量の LED (1)の L5から放出された光 、 LED (1)の L2からの放出された光の量と同程度の量の LED (1)の L6から放出さ れた光、及び、 LED (1)の L1からの放出された光の量と同程度の量の LED (1)の L 7から放出された光を含む。  However, light emitted from L5 of LED (1) adjacent to L4 of force LED (1) is emitted from L4 of LED (1) on the illumination target surface (imaging area) (Ai). A similar illuminance distribution having a peak displaced by m in the main scanning direction (Sx) from the position of the illuminance distribution peak on the illumination target surface (imaging area) (Ai) caused by light is given. Also, the light emitted from each of 1 ^^ (1) 6 to 1 illuminates the illumination target surface (imaging area) (Ai) with the same illuminance distribution (Di). Here, on the illumination target surface (imaging area) (Ai), the light on the optical axis of L4 of LED (1) is the smaller amount of light emitted from L1 of LED (1), LED (1 ) L2 of light emitted from L2, and a larger amount of light emitted from L3 of LED (2). Here, on the illumination target surface (imaging area) (Ai), the light on the optical axis of L4 of LED (1) is the same as the amount of light emitted from L3 of LED (l). The amount of light emitted from L5 of LED (1), the amount of light emitted from L6 of LED (1), and the amount of light emitted from L2 of LED (1), and The amount of light emitted from L1 of LED (1) is included in the same amount as the amount of light emitted from L1 of LED (1).
[0088] その結果、 LED (1)の L4の光軸上においては、 LED (1)の L1〜L7から放出され た光が、照明対象面 (撮像領域）（Ai)上で重畳されると共に照明対象面 (撮像領域） (Ai)を照明する。  As a result, on the optical axis of L4 of LED (1), the light emitted from L1 to L7 of LED (1) is superimposed on the illumination target surface (imaging area) (Ai) and Illuminate the illumination target surface (imaging area) (Ai).
[0089] 本発明の第一の実施例による照明方法においては、照明対象面 (撮像領域） (Ai) 上の任意の一点は、上述した Qの値の小数点以下の数字を切り捨てた数の個数の L ED又は上述した Qの値の小数点以下の数字を切り上げた数の個数（図 5において は、 6個又は 7個である）の LEDから放出される光で照明されることになる。その結果 、照明対象面 (撮像領域）（Ai)上の照度分布は、より均一なはり平坦な)ものとなる（ Total— Diとした概念を示す）。  [0089] In the illumination method according to the first embodiment of the present invention, an arbitrary point on the illumination target surface (imaging region) (Ai) is the number of numbers obtained by rounding down the numbers after the decimal point of the Q value described above. The LED is illuminated with the light emitted from the LED (or 6 or 7 in Fig. 5) of the number obtained by rounding up the number after the decimal point of the LED or Q value described above. As a result, the illuminance distribution on the illumination target surface (imaging region) (Ai) becomes more uniform and flat (shows the concept of “Total-Di”).
[0090] 図 5 (b)及び（d)に示すように、副走査方向（Sy)においては、複数の LED (1)の各 々から拡散する光は、第一の集束手段としての、各々の LED (1)に対応する回転放 物面鏡（2a)によって、ほぼ平行光に変換され、照明レンズ (3)を平行光のまま透過 する。その平行光は、集束レンズ (4a)力 照明装置に設けられてない場合には、そ のまま平行光として照明対象面 (撮像領域）（Ai)を照明する。この場合には、副走査 方向（Sy)において、照明対象面（撮像領域)での照度分布は、図 5 (d)において実 線で示すような個別の LED (1)に起因する照度分布（Each— Di)及び複数の LED ( 1)から放出される光を重畳して得られる照度分布 (Total— Di)である。すなわち、照 明装置が、集束レンズ (4a)を含まない場合には、照明対象面 (撮像領域） (Ai)にお ける照度分布は、比較的ブロードな照度分布である。 [0090] As shown in FIGS. 5 (b) and 5 (d), in the sub-scanning direction (Sy), the light diffused from each of the plurality of LEDs (1) It is converted into almost parallel light by the rotating parabolic mirror (2a) corresponding to the LED (1), and passes through the illumination lens (3) as parallel light. To do. If the collimated light is not provided in the focusing lens (4a) force illumination device, the illumination target surface (imaging area) (Ai) is illuminated as it is. In this case, in the sub-scanning direction (Sy), the illuminance distribution on the illumination target surface (imaging area) is the illuminance distribution due to the individual LEDs (1) as shown by the solid line in FIG. Each—Di) and illuminance distribution (Total—Di) obtained by superimposing the light emitted from a plurality of LEDs (1). That is, when the illumination device does not include the focusing lens (4a), the illuminance distribution on the illumination target surface (imaging area) (Ai) is a relatively broad illuminance distribution.
[0091] 一方、副走査方向（Sy)にお!/、て、照明対象面（撮像領域） (Ai)上でシャープな照 度分布が必要である場合には、第二の集束手段としての集束レンズ (4a)を用いる。 照明装置が、集束レンズ (4a)を含まない場合には、副走査方向（Sy)において、照 明対象面（撮像領域）（Ai)での照度分布は、図 5 (d)において二点鎖線で示すような 個別の LED (1)に起因する照度分布（Each— Di)及び複数の LED (1)から放出さ れる光を重畳して得られる照度分布 (Total— Di)である。すなわち、照明装置が、集 束レンズ (4a)を含む場合には、照明対象面 (撮像領域）（Ai)における照度分布は、 比較的シャープな照度分布である。  [0091] On the other hand, when a sharp illumination distribution on the illumination target surface (imaging area) (Ai) is required in the sub-scanning direction (Sy), Use the focusing lens (4a). When the illumination device does not include the focusing lens (4a), the illuminance distribution on the illumination target surface (imaging area) (Ai) in the sub-scanning direction (Sy) is shown by the two-dot chain line in FIG. These are the illuminance distribution (Each—Di) caused by individual LEDs (1) and the illuminance distribution (Total—Di) obtained by superimposing the light emitted from multiple LEDs (1). That is, when the lighting device includes the collecting lens (4a), the illuminance distribution on the illumination target surface (imaging area) (Ai) is a relatively sharp illuminance distribution.
[0092] なお、副走査方向（Sy)において、比較的シャープな照度分布と比較的ブロードな 照度分布との間の中間的な照度分布が照明対象面 (撮像領域）（Ai)で必要である 場合には、集束レンズ (4)の焦点距離を、集束レンズの焦点が、照明対象面 (撮像領 域）（Ai)の位置から離れるように、設定することによって、照明対象面（撮像領域） (A i)で任意の幅の照度分布を得ることができる。このように、主走査方向（Sx)において 、照明対象面 (撮像領域）（Ai)上の照度分布を、ほぼ一定に維持すると共に、副走 查方向（Sy)において、照明対象面（撮像領域）（Ai)上における照度分布を、シヤー プ又はブロードな照度分布に任意に設定することができる。  [0092] In the sub-scanning direction (Sy), an intermediate illuminance distribution between a relatively sharp illuminance distribution and a relatively broad illuminance distribution is necessary on the illumination target surface (imaging area) (Ai). In this case, the focal length of the focusing lens (4) is set so that the focal point of the focusing lens is away from the position of the illumination target surface (imaging area) (Ai). An illuminance distribution having an arbitrary width can be obtained with (A i). In this way, the illuminance distribution on the illumination target surface (imaging region) (Ai) is maintained substantially constant in the main scanning direction (Sx), and the illumination target surface (imaging region) is observed in the secondary scanning direction (Sy). ) The illuminance distribution on (Ai) can be arbitrarily set to a shear or broad illuminance distribution.
実施例 2  Example 2
[0093] 次に、本発明の第一の実施例の照明装置を有する第一の走行体を備えた本発明 の第二の実施例による画像読取装置を説明する。  Next, an image reading apparatus according to a second embodiment of the present invention provided with a first traveling body having the illumination device according to the first embodiment of the present invention will be described.
[0094] 図 6は、本発明の第二の実施例による画像読取装置の例を説明する図である。 FIG. 6 is a diagram for explaining an example of an image reading apparatus according to the second embodiment of the present invention.
[0095] 図 6 (a)は、本発明の第一の実施例による照明装置を用いる本発明の第二の実施 例による画像読取装置の上面図であり、図 6 (b)は、本発明の第一の実施例による照 明装置を用いる本発明の第二の実施例による画像読取装置の正面図である。 [0095] Fig. 6 (a) shows a second embodiment of the present invention using the lighting device according to the first embodiment of the present invention. FIG. 6B is a front view of the image reading apparatus according to the second embodiment of the present invention using the illumination apparatus according to the first embodiment of the present invention.
[0096] 図 6 (a)においては、図 5に示したような本発明の第一の実施例による照明装置に 加えて、変向ミラー（12)が描かれている。図 6 (b)において二点鎖線で示すように、 照明装置の光軸を折り曲げることなぐ照明装置を配置する場合には、撮像領域 (Ai )からの反射光の光路である読取系の光軸（読取光軸 (AxR) )に照明装置を配置す ることを回避するために、照明装置の全体の光軸（照明光軸 (Axl) )を、読取光軸 (A xR)から傾斜させてある。また、読取光軸 (AxR)に対する照明光軸 (Axl)の傾斜角 Θを小さくすると、コンタクトガラス（13)に垂直な方向における画像読取装置の大きさ を増加させることになるため、図 6 (b)における実線で示すように、折り返しミラー（6) を用いて、照明光軸 (Axl)を折り曲げることもできる。このようにして、照明装置を、コ ンタクトガラス（13)の面に平行に配置することによって、コンタクトガラス（13)に垂直 な方向における画像読取装置の大きさを、低減することが可能である。なお、照明装 置は、副走査方向（Sy)における撮像領域 (Ai)での目的とする照度分布に応じて、 集束レンズ (4a)を含んでも含まなくてもよい。  In FIG. 6 (a), a turning mirror (12) is depicted in addition to the illumination device according to the first embodiment of the present invention as shown in FIG. As shown by a two-dot chain line in FIG. 6 (b), when an illuminating device that does not bend the optical axis of the illuminating device is disposed, the optical axis of the reading system that is the optical path of the reflected light from the imaging region (Ai) In order to avoid placing an illuminating device on (reading optical axis (AxR)), the entire optical axis of the illuminating device (illuminating optical axis (Axl)) is tilted from the reading optical axis (A xR). is there. Further, if the inclination angle Θ of the illumination optical axis (Axl) with respect to the reading optical axis (AxR) is reduced, the size of the image reading device in the direction perpendicular to the contact glass (13) is increased. As indicated by the solid line in b), the illumination optical axis (Axl) can be bent using the folding mirror (6). In this way, the size of the image reading device in the direction perpendicular to the contact glass (13) can be reduced by arranging the illumination device in parallel to the surface of the contact glass (13). . The illumination device may or may not include the focusing lens (4a) depending on the target illuminance distribution in the imaging region (Ai) in the sub-scanning direction (Sy).
[0097] 図 6 (c)は、本発明の第一の実施例による照明装置の変形例を用いる本発明の第 二の実施例による画像読取装置の上面図であり、図 6 (d)は、本発明の第一の実施 例による照明装置の変形例を用いる本発明の第二の実施例による画像読取装置の 正面図である。  FIG. 6 (c) is a top view of the image reading apparatus according to the second embodiment of the present invention using a modification of the illumination apparatus according to the first embodiment of the present invention, and FIG. FIG. 7 is a front view of an image reading apparatus according to a second embodiment of the present invention using a modification of the illumination apparatus according to the first embodiment of the present invention.
[0098] 図 6 (c)及び (d)に示す照明装置においては、図 6 (a)及び (b)に示す集束レンズ（  [0098] In the illuminating device shown in Figs. 6 (c) and (d), the focusing lens shown in Figs. 6 (a) and 6 (b) (
4a)に代えて、集束ミラー (4b)を用いて!/、る。集束ミラー（4b)は、副走査方向（Sy) においては、撮像領域 (Ai)に焦点を有する放物面鏡であり、主走査方向（Sx)にお いては、集束機能を有さない反射面であるようなミラーである。また、集束ミラー（4b) は、図 6 (a)及び (b)に示す折り返しミラー（12)の機能を兼ね備えることができるため 、照明装置の構成部品の数を低減すると共に、コンタクトガラス（13)に垂直な方向に おける画像読取装置の大きさを、低減すること力 Sできる。なお、読取光軸 (AxR)の折 り曲げ方向は、図 6における左右の方向のいずれでもよい。  Instead of 4a), use a focusing mirror (4b)! The focusing mirror (4b) is a parabolic mirror having a focal point in the imaging area (Ai) in the sub-scanning direction (Sy), and a reflection having no focusing function in the main scanning direction (Sx). It is a mirror that is a surface. Further, since the focusing mirror (4b) can have the function of the folding mirror (12) shown in FIGS. 6 (a) and 6 (b), the number of components of the lighting device can be reduced and the contact glass (13 It is possible to reduce the size of the image reading device in the direction perpendicular to). Note that the bending direction of the reading optical axis (AxR) may be any of the left and right directions in FIG.
[0099] 図 6に示すような画像読取装置の構成を採用することによって、画像読取装置の主 走査方向（Sx)においては、撮像領域 (Ai)で、複数の LED (図 6においては、 nが 10 以上である設計は、容易である）から放出される光束力 重畳されると共に照射され ているので、複数の LEDの発光効率のバラツキは、平均化され、撮像領域 ( での 照度ムラが、軽減される。一般的に製造された LEDを光源として用いる場合には、同 一のランクに属する LEDを用いて、 5個以上の LEDから放出される光束が重なり合う ように照明装置を設計すれば、主走査方向（Sx)における撮像領域 (Ai)の全体での 照度ムラを、 20%程度まで抑制することができる。また、 10個以上の LEDから放出さ れる光束が重なり合うように照明装置を設計すれば、主走査方向（Sx)における撮像 領域 (Ai)の全体での照度ムラを、 10%未満まで抑制することも可能となる。それに 応じて、撮像領域 (Ai)における照度ムラを、電気的に補正することによって、撮像領 域 (Ai)における照度の低い場所でも、画像信号のノイズを低減することが可能となり 、画像信号の品質を向上させることが可能なる。 [0099] By adopting the configuration of the image reading apparatus as shown in FIG. In the scanning direction (Sx), in the imaging region (Ai), the luminous flux force emitted from a plurality of LEDs (in FIG. 6, the design where n is 10 or more is easy) is superimposed and irradiated. Therefore, the variation in luminous efficiency of multiple LEDs is averaged, and the illuminance unevenness in the imaging area (is reduced. When using a generally manufactured LED as the light source, the same rank is achieved. If the illuminating device is designed so that the luminous fluxes emitted from five or more LEDs overlap with each other, the illuminance unevenness of the entire imaging area (Ai) in the main scanning direction (Sx) is reduced by about 20%. In addition, if the lighting device is designed so that the luminous fluxes emitted from 10 or more LEDs overlap, the illuminance unevenness in the entire imaging area (Ai) in the main scanning direction (Sx) can be reduced. It can be reduced to less than 10%. By electrically correcting the illuminance unevenness in the imaging area (Ai), it is possible to reduce the noise of the image signal even in a place where the illuminance is low in the imaging area (Ai), thereby improving the quality of the image signal. It becomes possible.
実施例 3  Example 3
[0100] 次に、ブック原稿の中央部分の読み取りを向上させることができる本発明の第三の 実施例による画像読取装置を説明する。  Next, an image reading apparatus according to a third embodiment of the present invention that can improve the reading of the central portion of a book document will be described.
[0101] 図 7は、本発明の第三の実施例による画像読取装置の例を説明する図である。図 7 FIG. 7 is a diagram for explaining an example of an image reading apparatus according to the third embodiment of the present invention. Fig 7
(a)、 (b)、 (c)、（d)、（e)及び (f)は、それぞれ、ブック原稿の中央部分の読み取りを 向上させることができる本発明の第三の実施例による画像読取装置の例を示す図で ある。  (a), (b), (c), (d), (e) and (f) are images according to the third embodiment of the present invention that can improve the reading of the central portion of the book document, respectively. It is a figure which shows the example of a reader.
[0102] 図 7 (a)に示すような画像読取装置の例においては、図 6 (a)及び (b)に示すような 画像読取装置における、集束レンズ (4a)を透過する光の光束のうち、副走査方向に おいて、照明光軸 (Axl)よりもコンタクトガラス（13)側の光束を、読取光軸 (AxR)よ りも後側で、折り返しミラー A (6a)によって、撮像領域 (Ai)へ反射させる一方で、集 束レンズ (4a)を透過する光の光束のうち、副走査方向において、照明光軸 (Axl)よ りも変向ミラー（12)側の光束を、読取光軸 (AxR)よりも前側で、折り返しミラー B (6b )によって、撮像領域 (Ai)へ反射させる（なお、照明光軸 (Axl)よりも変向ミラー（12) 側の光束を、読取光軸 (AxR)よりも前側で、折り返すので、折返しミラー A(6a)の大 きさを、低減することができ、照明装置の全体を、読取光軸 (AxR)側に近付けること カできる。）。ここで、集束レンズ (4a)の焦点距離は、集束レンズ (4a)を透過する光 の光束の全てについて共通であるので、折り返しミラー A及び B (6a, 6b)の配置を、 集束レンズ (4a)から撮像領域 (Ai)までの距離が一定であるように、調整することによ つて、図 5 (a)に示すものと同様の照度分布を得ることができる。し力、しながら、集束レ ンズ (4a)を透過する光の光束の全てについて、集束レンズ (4a)力、ら撮像領域 (Ai) までの距離を共通にする必要はない。集束レンズ (4a)を透過する光の光束の全てに ついて、集束レンズ (4a)力も撮像領域 (Ai)までの距離が共通でない場合には、照 明光軸 (Axl)よりもコンタクトガラス（13)側の光束の焦点の位置と照明光軸 (Axl)よ りも変向ミラー（12)側の光束の焦点の位置との間に、撮像領域 (Ai)が位置するよう に、折り返しミラー A及び B (6a, 6b)の配置を設定することが好ましい。 [0102] In the example of the image reading apparatus as shown in Fig. 7 (a), in the image reading apparatus as shown in Figs. 6 (a) and (b), the luminous flux of the light transmitted through the focusing lens (4a). Among them, in the sub-scanning direction, the light flux on the contact glass (13) side from the illumination optical axis (Axl) is reflected behind the reading optical axis (AxR) by the folding mirror A (6a). Of the light flux that is reflected to (Ai) and is transmitted through the aggregating lens (4a), the light flux on the direction of the deflecting mirror (12) from the illumination optical axis (Axl) is read in the sub-scanning direction. Reflected to the imaging area (Ai) by the folding mirror B (6b) on the front side of the optical axis (AxR) (Note that the light beam on the direction mirror (12) side of the illumination optical axis (Axl) is read light. Since it folds in front of the axis (AxR), the size of the folding mirror A (6a) can be reduced, and the entire illuminator should be closer to the reading optical axis (AxR) side. I can do it. ). Here, since the focal length of the focusing lens (4a) is common to all the light beams transmitted through the focusing lens (4a), the arrangement of the folding mirrors A and B (6a, 6b) is determined by the focusing lens (4a). By adjusting the distance so that the distance from the imaging area (Ai) is constant, an illuminance distribution similar to that shown in Fig. 5 (a) can be obtained. However, it is not necessary to make the distance from the focusing lens (4a) force to the imaging area (Ai) common to all the light beams transmitted through the focusing lens (4a). For all light beams that pass through the focusing lens (4a), if the focusing lens (4a) force and the distance to the imaging area (Ai) are not the same, contact glass (13) rather than the illumination optical axis (Axl) The folding mirror A and the mirror A and the imaging region (Ai) are positioned between the focal position of the luminous flux on the side and the focal position of the luminous flux on the deflecting mirror (12) side with respect to the illumination optical axis (Axl). It is preferable to set the arrangement of B (6a, 6b).
[0103] 図 7 (b)に示すような画像読取装置の例においては、図 7 (a)に示すような画像読取 装置とは逆に、集束レンズ (4a)を透過する光の光束のうち、副走査方向において、 照明光軸 (Axl)よりもコンタクトガラス（13)側の光束を、読取光軸 (AxR)よりも前側 で、折り返しミラー B (6b)によって、撮像領域 (Ai)へ反射させる一方で、集束レンズ（ 4a)を透過する光の光束のうち、副走査方向において、照明光軸 (Axl)よりも変向ミ ラー（12)側の光束を、読取光軸 (AxR)よりも後側で、折り返しミラー A(6a)によって 、撮像領域 (Ai)へ反射させる。さらに、照明光軸 (Axl)よりもコンタクトガラス（13)側 の光束を、撮像領域 (Ai)よりも後側 (FB)で集束させ、照明光軸 (Axl)よりも変向ミラ 一（12)側の光束を、撮像領域 (Ai)の前側（FA)で集束させている。この場合には、 ブック原稿の原稿面の中央部分を、照明光軸 (Axl)よりもコンタクトガラス（13)側の 光束で照射すると共に、照明光軸 (Axl)よりも変向ミラー（12)側の光束を、ブック原 稿の原稿面に集束させずに拡散させてブック原稿に照射することができる。その結果 、ブック原稿の中央部分に光束を良好なバランスで照射することができ、ブック原稿 の中央部分を黒色画像として読み取ることを防止又は低減することが可能となる。  [0103] In the example of the image reading apparatus as shown in Fig. 7 (b), contrary to the image reading apparatus as shown in Fig. 7 (a), out of the luminous flux of the light transmitted through the focusing lens (4a). In the sub-scanning direction, the light flux on the contact glass (13) side from the illumination optical axis (Axl) is reflected to the imaging area (Ai) by the folding mirror B (6b) on the front side from the reading optical axis (AxR). On the other hand, out of the light flux transmitted through the focusing lens (4a), the light flux on the direction of the mirror (12) that is more than the illumination optical axis (Axl) in the sub-scanning direction is read from the reading optical axis (AxR). On the rear side, the light is reflected to the imaging region (Ai) by the folding mirror A (6a). Furthermore, the light flux on the contact glass (13) side of the illumination optical axis (Axl) is focused on the rear side (FB) of the imaging area (Ai), and the direction of the mirror is changed more than the illumination optical axis (Axl) (12 ) Side beam is focused on the front side (FA) of the imaging area (Ai). In this case, the central part of the document surface of the book document is irradiated with the light flux on the contact glass (13) side from the illumination optical axis (Axl), and the deflecting mirror (12) from the illumination optical axis (Axl). The light beam on the side can be diffused without being focused on the original surface of the book original, and can be irradiated onto the book original. As a result, it is possible to irradiate the central portion of the book document with a good balance of light and to prevent or reduce reading of the central portion of the book document as a black image.
[0104] 図 7 (c)に示すような画像読取装置の例においては、図 6 (c)及び (d)に示すような 画像読取装置における、集束ミラーによって反射させられる光の光束のうち、副走査 方向において、照明光軸 (Axl)よりもコンタクトガラス（13)側の光束を、読取光軸 (A xR)よりも前側で、折り返しミラー（6)によって、集束ミラー B (4b2)へ反射させると共 に、集束ミラー B (4b2)によって、撮像領域 (Ai)へ反射させる一方で、集束ミラーに よって反射させられる光の光束のうち、副走査方向において、照明光軸 (Axl)よりも 変向ミラー（12)側の光束を、読取光軸 (AxR)よりも後側で、集束ミラー A(4bl)によ つて、撮像領域 (Ai)へ反射させる。ここで、集束ミラー A (4bl)及び集束ミラー B (4b 2)は、主走査方向においては平行平面であり、副走査方向においては撮像領域 (A i)に焦点を持つ放物面であるようなミラーである。なお、照明光軸 (Axl)よりも変向ミ ラー（12)側の光束を、集束ミラー A (4bl)によって、反射させる必要がないので、集 束ミラー A (4bl)の大きさを、低減すること力 Sできる。図 7 (c)においては、照明光軸（ Axl)よりもコンタクトガラス（13)側の光束及び照明光軸 (Axl)よりも変向ミラー（12) 側の光束の両方を撮像領域 (Ai)に集束させている力 S、副走査方向における集束ミラ 一 A (4M)及び集束ミラー B (4b2)の焦点距離を適宜設定することによって、原稿面 のタイプ及び要求される照度分布に依存して、それぞれ独立に撮像領域 (Ai)の前 後に集束させることあでさる。 [0104] In the example of the image reading apparatus as shown in Fig. 7 (c), in the light beam reflected by the focusing mirror in the image reading apparatus as shown in Figs. 6 (c) and (d), In the sub-scanning direction, the light flux on the contact glass (13) side from the illumination optical axis (Axl) is reflected to the focusing mirror B (4b2) by the folding mirror (6) before the reading optical axis (A xR). Both In addition, while the light is reflected by the focusing mirror B (4b2) to the imaging region (Ai), the light beam reflected by the focusing mirror is more deflected than the illumination optical axis (Axl) in the sub-scanning direction. The light beam on the (12) side is reflected to the imaging area (Ai) by the focusing mirror A (4bl) on the rear side of the reading optical axis (AxR). Here, the focusing mirror A (4bl) and the focusing mirror B (4b 2) are parallel planes in the main scanning direction, and appear to be paraboloids having a focal point in the imaging region (A i) in the sub-scanning direction. It is a mirror. The size of the focusing mirror A (4bl) is reduced because there is no need to reflect the light beam on the direction of the mirror (12) with respect to the illumination optical axis (Axl) by the focusing mirror A (4bl). The power to do S. In Fig. 7 (c), both the luminous flux on the contact glass (13) side from the illumination optical axis (Axl) and the luminous flux on the deflecting mirror (12) side from the illumination optical axis (Axl) are both captured in the imaging region (Ai). Depending on the type of document surface and the required illuminance distribution by appropriately setting the focal length of the focusing force S and the focal length of the focusing mirror A (4M) and focusing mirror B (4b2) in the sub-scanning direction In this case, focusing is performed before and after the imaging area (Ai) independently.
[0105] 図 7 (d)に示すような画像読取装置の例においては、図 7 (c)に示すような画像読取 装置における、照明光軸 (Axl)よりもコンタクトガラス（13)側の概略平行光の光束を 、副走査方向において、集束ミラー B (4b2)を用いることなぐ読取光軸 (AxR)よりも 前側で折り返しミラー（6)によって、撮像領域 (Ai)へ平行光束として反射させる。この 場合には、副走査方向において、照明光軸 (Axl)よりもコンタクトガラス（13)側の概 略平行光の光束による撮像領域 (Ai)での照度分布は、ブロードな分布を示し、照明 光軸 (Axl)よりも変向ミラー（12)側の光束による撮像領域 (Ai)での照度分布は、シ ヤープな分布を示す。 [0105] In the example of the image reading apparatus as shown in Fig. 7 (d), in the image reading apparatus as shown in Fig. 7 (c), the outline closer to the contact glass (13) side than the illumination optical axis (Axl). The parallel light beam is reflected as a parallel light beam to the imaging region (Ai) by the folding mirror (6) in front of the reading optical axis (AxR) without using the focusing mirror B (4b2) in the sub-scanning direction. In this case, in the sub-scanning direction, the illuminance distribution in the imaging region (Ai) by the substantially parallel light beam on the contact glass (13) side from the illumination optical axis (Axl) shows a broad distribution, The illuminance distribution in the imaging area (Ai) due to the light flux on the direction of the deflecting mirror (12) with respect to the optical axis (Axl) shows a sharp distribution.
[0106] 図 7 (e)及び図 7 (f)に示すような画像読取装置の例においては、集束レンズ及び 集束ミラーのいずれも用いない画像読取装置の例である。図 7 (e)に示すような画像 読取装置の例においては、照明レンズを透過した概略平行光の光束のうち、照明光 軸 (Axl)よりもコンタクトガラス（13)側の光束を、読取光軸 (AxR)よりも後側で撮像 領域 (Ai)へ反射させ、照明光軸 (Axl)よりも変向ミラー（12)側の光束を、読取光軸 (AxR)よりも前側で撮像領域 (Ai)へ反射させる。同様に、図 7 (f)に示すような画像 読取装置の例においては、照明レンズを透過した概略平行光の光束のうち、照明光 軸 (Axl)よりもコンタクトガラス（13)側の光束を、読取光軸 (AxR)よりも前側で撮像 領域 (Ai)へ反射させ、照明光軸 (Axl)よりも変向ミラー（12)側の光束を、読取光軸 (AxR)よりも後側で撮像領域 (Ai)へ反射させる。これらの場合には、集束レンズ又 は集束ミラーを用いる画像読取装置において、照明装置の光の利用効率は、低下す るが、撮像領域 (Ai)における照度分布は、ブロードであり、ブック原稿の中央部分を 黒色画像として読み取ることをより有効に防止又は低減することができる。 The example of the image reading apparatus as shown in FIGS. 7E and 7F is an example of an image reading apparatus that uses neither a focusing lens nor a focusing mirror. In the example of the image reading apparatus as shown in FIG. 7 (e), the light beam on the contact glass (13) side from the illumination optical axis (Axl) out of the substantially parallel light beam transmitted through the illumination lens is read light. Reflected to the imaging area (Ai) behind the axis (AxR), and the luminous flux on the deflecting mirror (12) side from the illumination optical axis (Axl) is reflected to the imaging area (AxR) before the reading optical axis (AxR). Reflect to Ai). Similarly, in the example of the image reading apparatus as shown in FIG. 7 (f), the illumination light out of the substantially parallel light beams transmitted through the illumination lens. The light beam on the contact glass (13) side of the axis (Axl) is reflected to the imaging area (Ai) on the front side of the reading optical axis (AxR), and the deflecting mirror (12) side of the illumination optical axis (Axl) side Are reflected to the imaging area (Ai) behind the reading optical axis (AxR). In these cases, in the image reading apparatus using the focusing lens or the focusing mirror, the light use efficiency of the illuminating device is reduced, but the illuminance distribution in the imaging area (Ai) is broad, and the book document Reading the central portion as a black image can be prevented or reduced more effectively.
[0107] 図 7において、画像読取装置における集束レンズ、折返しミラー、及び集束ミラーの 配置の例を示してきた力 集束レンズ、折返しミラー、及び集束ミラーの配置は、任意 であり、図 7に示したものに限定されない。また、図 7に示す画像読取装置の例では、 光束を、照明光軸 (Axl)の前後に、半分に分割しているが、光束の分割の割合は、 5 ： 5に限定されず、撮像領域 (Ai)における集束の程度又は原稿のタイプ応じて、任意 に設定され、例えば、 6 : 4又は 3 : 7であってもよい。  FIG. 7 shows an example of the arrangement of the focusing lens, the folding mirror, and the focusing mirror in the image reading apparatus. The arrangement of the focusing lens, the folding mirror, and the focusing mirror is arbitrary, and is shown in FIG. It is not limited to that. In the example of the image reading apparatus shown in FIG. 7, the light beam is divided in half before and after the illumination optical axis (Axl). However, the ratio of the light beam division is not limited to 5: 5, and imaging is performed. It is arbitrarily set according to the degree of focusing in the area (Ai) or the type of document, and may be 6: 4 or 3: 7, for example.
[0108] 図 8は、本発明の第三の実施例による画像読取装置の変形例を説明する図である 。図 8 (a)は、本発明の第三の実施例による画像読取装置の第一の変形例を説明す る図であり、図 8 (b)は、本発明の第三の実施例による画像読取装置の第二の変形 例を説明する図である。  FIG. 8 is a diagram for explaining a modification of the image reading apparatus according to the third embodiment of the present invention. FIG. 8 (a) is a diagram for explaining a first modification of the image reading apparatus according to the third embodiment of the present invention, and FIG. 8 (b) is an image according to the third embodiment of the present invention. FIG. 10 is a diagram illustrating a second modification of the reading device.
[0109] 図 6に示す画像読取装置の例においては、読取光軸 (AxR)に対して前側又は後 側に照明装置本体を配置して、撮像領域 (Ai)を照明しており、図 7に示す画像読取 装置の例においては、光束を二つに分割して、読取光軸 (AxR)の前側及び後側の 両方から撮像領域 (Ai)を照明している。これに対して、図 8に示す画像読取装置の 例にぉレ、ては、二つの照明装置本体を読取光軸 (AxR)の前側及び後側の両方に 配置し、二つの照明装置本体を使用して、読取光軸 (AxR)の前側及び後側の両方 力、ら撮像領域 (Ai)を照明している。図 8 (a)の実線に示すような画像読取装置の例 におレ、ては、集束レンズ (4a)を含む二つの照明装置本体の照明光軸 (Axl)を折り 曲げることなく、二つの照明装置本体を読取光軸 (AxR)に対して斜めに配置してい る。この場合には、コンタクトガラス（13)の面に平行な方向における画像読取装置の 大きさを低減すること力 Sできる。し力、しな力 Sら、図 8 (a)の二点差線で示すように、折り 返しミラー（6)を用いて、照明装置本体を、コンタクトガラス（13)の面に対して平行に 酉己置することもできる。この場合には、コンタクトガラス（13)の面に垂直な方向におけ る画像読取装置の大きさを低減することができる。 In the example of the image reading apparatus shown in FIG. 6, the illuminating device main body is arranged on the front side or the rear side with respect to the reading optical axis (AxR) to illuminate the imaging region (Ai). In the example of the image reading apparatus shown in FIG. 1, the light flux is divided into two and the imaging area (Ai) is illuminated from both the front side and the rear side of the reading optical axis (AxR). On the other hand, in the example of the image reading apparatus shown in FIG. 8, two illumination device bodies are arranged on both the front side and the rear side of the reading optical axis (AxR), and the two illumination device bodies are arranged. It is used to illuminate the imaging area (Ai) from both the front and rear forces of the reading optical axis (AxR). In the example of the image reading apparatus as shown by the solid line in FIG. 8 (a), the two light source bodies (Axl) including the focusing lens (4a) are not bent and the two optical axes (Axl) are not bent. The main body of the illuminating device is arranged obliquely with respect to the reading optical axis (AxR). In this case, it is possible to reduce the size of the image reading device in the direction parallel to the surface of the contact glass (13). As shown by the two-dot difference line in Fig. 8 (a), the illuminating device body is placed parallel to the surface of the contact glass (13) using the folding mirror (6). You can also place yourself. In this case, the size of the image reading device in the direction perpendicular to the surface of the contact glass (13) can be reduced.
[0110] 図 8 (b)に示すような画像読取装置の例においては、放物面鏡である集束ミラー（4 b)及び折り返しミラー（6)を含む二つの照明装置本体を用いて!/、る。 In the example of the image reading apparatus as shown in FIG. 8 (b), two illumination device bodies including a focusing mirror (4b) and a folding mirror (6), which are parabolic mirrors, are used! / RU
[0111] なお、図 8に示すような画像読取装置の例においても、二つの照明装置本体の一 方又は両方力 集束レンズ及び集束ミラーのいずれも含まないものであってもよぐ 図 7に示すような画像読取装置の例における変形を適用することができる。 Note that the example of the image reading apparatus as shown in FIG. 8 may not include either one of the two illuminating device bodies or both the force focusing lens and the focusing mirror. Modifications in the example of the image reading apparatus as shown can be applied.
[0112] 本発明の第二の又は第三の実施例においては、照明装置を第 1走行体上に設け る画像読取装置の構成の例を説明した。 [0112] In the second or third embodiment of the present invention, the example of the configuration of the image reading device in which the illumination device is provided on the first traveling body has been described.
[0113] 次に、本発明の実施形態による照明装置において、 LEDから拡散する光束を、第 一の集束段階で、平行光に変換する手段の詳細を説明する。 Next, in the illumination device according to the embodiment of the present invention, details of means for converting the light beam diffusing from the LED into parallel light in the first focusing stage will be described.
[0114] 図 9は、回転放物面鏡を用いて LEDから拡散する光束を平行光に変換する手段を 説明する図である。図 9 (a)は、 LED及び回転放物面鏡を含む光源の正面図であり[0114] FIG. 9 is a diagram for explaining a means for converting a light beam diffusing from an LED into parallel light using a rotary parabolic mirror. Figure 9 (a) is a front view of a light source including LEDs and a rotating parabolic mirror.
、図 9 (b)は、 LED及び回転放物面鏡を含む光源の側面図である。 FIG. 9 (b) is a side view of a light source including an LED and a rotating parabolic mirror.
[0115] 図 9に示すように、 X軸、 y軸、及び z軸を定義し、 x軸、 y軸、及び z軸の交点に LED [0115] As shown in Fig. 9, the X, y, and z axes are defined, and the LED is at the intersection of the x, y, and z axes.
(1)の発光面の中心が配置される。また、回転放物面鏡（2a)の焦点距離は、 fであり The center of the light emitting surface of (1) is arranged. The focal length of the parabolic mirror (2a) is f
、回転放物面鏡（2a)の回転放物面は、式 The paraboloid of the parabolic mirror (2a) is
[0116] [数 4] y = ^4f(x - f) [0116] [Equation 4] y = ^ 4f (x-f)
[0117] によって表される放物線を、 X軸まわりに回転させることによって得られる回転放物面 である。回転放物面の焦点位置 (Pf)には、 LED (1)の発光面の中心が配置される。 ここで、 LED (1)の発光面は、回転放物面鏡（2a)に面する。図 9 (a)及び (b)に示す ように、 LED (l)は、二つの電極（21)にリード線（22)を介して接続され、透明樹脂（ 23)の中に埋め込まれている。 [0117] is a paraboloid obtained by rotating the parabola represented by X around the X axis. The center of the light emitting surface of the LED (1) is arranged at the focal position (Pf) of the paraboloid. Here, the light emitting surface of the LED (1) faces the rotary parabolic mirror (2a). As shown in Fig. 9 (a) and (b), the LED (l) is connected to the two electrodes (21) via the lead wire (22) and embedded in the transparent resin (23). .
[0118] 図 9の二点鎖線で示すように、回転放物面鏡（2a)の外周は、円形であってもよいが 、図 9 (a)における LED (1)の発光面からの放射ベクトル (Vr)の分布に示すように、 回転放物面鏡（2a)の X軸の近傍への強度に比べ周辺部分への強度が低いので、主 走査方向（Sx) (例えば、 z方向）における回転放物面（2a)を配置する密度を増加さ せるために、主走査方向（Sx)における回転放物面鏡（2a)の周辺部分を切り取って もよい (すなわち、回転放物面鏡（2a)を側面から見たとき、回転放物面鏡（2a)は、 小判状の形状を有する)。また、照明装置の照明効率を若干の低下を犠牲にして、 照明装置を小型化するために、副走査方向（Sy) (例えば、 y方向）における回転放 物面鏡（2a)の周辺部分を切り取ってもよ!/、（すなわち、回転放物面鏡（2a)を側面か ら見たとき、回転放物面鏡（2a)は、四角の形状を有する）。なお、 LED (1)の発光面 は面積を持っているので回転放物面の焦点位置で発光する場所はただ一点でしか なぐ他の位置で発光する光は全て回転放物面の焦点位置から外れている。即ち、 回転放物面鏡（2a)の焦点位置から発光する発光ベクトルは全て平行光となる力 そ れ以外の場所から発光する発光ベクトルは回転放物面鏡（2a)で反射されると全て平 行光からずれてしまう。そのずれ方は回転放物面鏡（2a)の焦点位置から遠くになる ほど大きくなる。 [0118] As shown by the two-dot chain line in Fig. 9, the outer periphery of the rotating parabolic mirror (2a) may be circular, but radiation from the light emitting surface of LED (1) in Fig. 9 (a). As shown in the distribution of the vector (Vr), the intensity of the rotating paraboloid mirror (2a) in the vicinity is lower than that in the vicinity of the X axis, so the main scanning direction (Sx) (eg, z direction) Increased density to place a rotating paraboloid (2a) in For this reason, the peripheral part of the rotating parabolic mirror (2a) in the main scanning direction (Sx) may be cut off (that is, when the rotating parabolic mirror (2a) is viewed from the side, the rotating parabolic mirror is (2a) has an oval shape). In addition, in order to reduce the size of the lighting device at the expense of a slight decrease in the lighting efficiency of the lighting device, the peripheral part of the rotary parabolic mirror (2a) in the sub-scanning direction (Sy) (for example, the y direction) is You can cut it out! / (Ie, when the paraboloid mirror (2a) is viewed from the side, the paraboloid mirror (2a) has a square shape). Note that the light emitting surface of LED (1) has an area, so there is only one place where light is emitted at the focal position of the rotating paraboloid. All light emitted at other positions is from the focal position of the rotating paraboloid. It is off. That is, the light emission vectors emitted from the focal position of the rotary parabolic mirror (2a) are all parallel light. The light emission vectors emitted from other locations are all reflected when reflected by the rotary parabolic mirror (2a). It will deviate from the parallel light. The deviation increases as the distance from the focal point of the parabolic mirror (2a) increases.
[0119] 図 9 (c)は、図 9 (a)及び (b)に示すような回転放物面鏡及び LEDを含む光源から 放出される光をある一定の距離を置!/、た光軸の近傍のある一点を通過する（或いは 、ある一点に向かってくる）光のベクトル強度を相対値で示す配光特性図である。図 9 (c)の横軸は、回転放物面鏡の光軸からの角度 (° )を表し、図 9 (c)の縦軸は、ある 点を通過する光ベクトルの強度の最強値を基準とする相対放射強度 RP (%)を表す 。回転放物面鏡の光軸 (X軸）と平行な成分（0度）が最も強いが、角度を持つ成分も ある。 （その量は角度がつくに従って少なくなつていく。 50%まで落ちる角度を半ィ直 幅と称し、この例では ± 5度である。 )  [0119] Fig. 9 (c) shows the light emitted from a light source including a rotating paraboloid mirror and LED as shown in Figs. 9 (a) and 9 (b) at a certain distance. It is a light distribution characteristic figure which shows the vector intensity of the light which passes a certain point of the vicinity of an axis | shaft (or comes toward a certain point) by a relative value. The horizontal axis in Fig. 9 (c) represents the angle (°) from the optical axis of the parabolic mirror, and the vertical axis in Fig. 9 (c) represents the strongest value of the intensity of the light vector passing through a certain point. Represents the reference relative radiant intensity RP (%). The component parallel to the optical axis (X-axis) of the parabolic mirror (X axis) is strongest (0 degree), but there is also a component with an angle. (The amount decreases as the angle increases. The angle that falls to 50% is called the half-width, and in this example is ± 5 degrees.)
[0120] 図 10は、凸レンズを用いて LEDから拡散する光束を平行光に変換する手段を説 明する図である。図 10 (a)は、 LED及び凸レンズを含む光源の正面図であり、図 10 ( b)は、 LED及び凸レンズを含む光源の側面図である。  [0120] FIG. 10 is a diagram illustrating a means for converting a light beam diffusing from an LED into parallel light using a convex lens. 10 (a) is a front view of a light source including an LED and a convex lens, and FIG. 10 (b) is a side view of the light source including an LED and a convex lens.
[0121] 図 10 (a)及び (b)に示す LED及び凸レンズを含む光源は、砲弾型と呼ばれるもの であり、ベース 25に取り付けられた LED (1)が、樹脂材料で作られた凸レンズの形状 を備えたフードレンズ（24)で覆われている。 LED (l)は、リード線（22)を介して電極 (21)に接続される。ここで、 LED (1)の発光面の中心が、凸レンズであるフードレン ズ（24)の焦点位置 (Pf)に配置されている。また、フードレンズ (24)のレンズの大き さは、図 10 (a)に示すような、凸レンズ形状の周辺に入射する光の角度力 臨界角 Θ 以下になるように決定されてレ、る。 [0121] The light source including the LED and the convex lens shown in Figs. 10 (a) and 10 (b) is called a cannonball type, and the LED (1) attached to the base 25 is a convex lens made of a resin material. It is covered with a hood lens (24) with a shape. LED (l) is connected to the electrode (21) via the lead wire (22). Here, the center of the light emitting surface of the LED (1) is arranged at the focal position (Pf) of the hood lens (24) which is a convex lens. Also, the lens size of the hood lens (24) As shown in Fig. 10 (a), the angular force of light incident on the periphery of the convex lens shape is determined to be less than the critical angle Θ.
[0122] 図 10 (b)の二点鎖線で示すように、フードレンズ（24)の外周は、円形であってもよ いが、図 10における LED (1)の発光面からの放射ベクトル (Vr)の分布に示すように 、フードレンズ（24)の周辺部分を通過する光の強度は、低いので、主走査方向（Sx ) (例えば、 z方向）におけるフードレンズ (24)を配置する密度を増加させるために、 主走査方向（Sx)におけるフードレンズ（24)の周辺部分を切り取ってもよい（すなわ ち、フードレンズ（24)を側面から見たとき、フードレンズ（24)は、小判状の形状を有 する)。また、照明装置の照明効率を若干の低下を犠牲にして、照明装置を小型化 するために、副走査方向（Sy) (例えば、 y方向）におけるフードレンズ（24)の周辺部 分を切り取ってもよい（すなわち、フードレンズ（24)を側面から見たとき、フードレンズ (24)は、四角の形状を有する）。  [0122] As indicated by the two-dot chain line in Fig. 10 (b), the outer periphery of the hood lens (24) may be circular, but the radiation vector from the light emitting surface of LED (1) in Fig. 10 ( As shown in the distribution of Vr), since the intensity of light passing through the peripheral portion of the hood lens (24) is low, the density at which the hood lens (24) is arranged in the main scanning direction (Sx) (for example, z direction) In order to increase the image, the peripheral portion of the hood lens (24) in the main scanning direction (Sx) may be cut off (that is, when the hood lens (24) is viewed from the side, the hood lens (24) Oval shape). Further, in order to reduce the size of the lighting device at the expense of a slight decrease in the lighting efficiency of the lighting device, the peripheral portion of the hood lens (24) in the sub-scanning direction (Sy) (for example, y direction) is cut off. (Ie, when the hood lens (24) is viewed from the side, the hood lens (24) has a square shape).
[0123] さらに、フードレンズ（24)の側面の全面は、鏡面であることが好ましい。この場合に は、フードレンズ (24)の側面に入射する光を鏡面で反射させることによって、フード レンズ（24)の側面に入射する光を、フードレンズ（24)のレンズ面から（平行光では ないが）射出させることができる。ただし、主走査方向（Sx) (例えば、 z方向）における フードレンズ（24)の側面は、非鏡面であってもよい。主走査方向（Sx) (z方向）につ いては、フードレンズの側面から逃げる光を、隣接するフードレンズに入射させること によって、有効に利用することが可能である。  [0123] Furthermore, the entire side surface of the hood lens (24) is preferably a mirror surface. In this case, the light incident on the side surface of the hood lens (24) is reflected by the mirror surface to reflect the light incident on the side surface of the hood lens (24) from the lens surface of the hood lens (24). Can be injected) However, the side surface of the hood lens (24) in the main scanning direction (Sx) (for example, the z direction) may be a non-mirror surface. In the main scanning direction (Sx) (z direction), light that escapes from the side surface of the hood lens can be used effectively by being incident on the adjacent hood lens.
[0124] なお、図 5〜図 9に示す照明装置における LED及び回転放物面鏡を含む光源を、 図 10 (a)及び (b)に示すような LED及び凸レンズを含む光源で置き換えてもよい。ま た、図 10に示すような光源において、フードの先端を平面のままとし、フードレンズ（2 4)に対応する凸レンズを独立して配置することも可能である。  [0124] Note that the light source including the LED and the rotating paraboloid mirror in the illumination device illustrated in FIGS. 5 to 9 may be replaced with the light source including the LED and the convex lens as illustrated in FIGS. 10 (a) and (b). Good. Further, in the light source as shown in FIG. 10, it is also possible to arrange the convex lens corresponding to the hood lens (24) independently while keeping the tip of the hood flat.
[0125] さらに、 LED (1)の発光面の中心が、フードレンズ（24)の焦点に位置するときは、 フードレンズ（24)を透過する光は、概略平行光であるが、 LED (1)の発光面は面積 を持っているのでフードレンズ（24)の焦点位置から外れた位置力 発光している光 束はフードレンズ（24)を透過すると光軸と平行の光束とはならない。また、図 10 (a) 及び (b)に示すような LED及び凸レンズを含む光源の配向特性は、図 9 (c)に示すよ うな LED及び回転放物面鏡を含む光源の配向特性と同様の傾向を有する。 [0125] Furthermore, when the center of the light emitting surface of the LED (1) is located at the focal point of the hood lens (24), the light transmitted through the hood lens (24) is substantially parallel light, but the LED (1 The light emitting surface of) has an area, so the position force deviated from the focal position of the hood lens (24). The emitted light flux does not become a light beam parallel to the optical axis when passing through the hood lens (24). In addition, the orientation characteristics of a light source including LEDs and convex lenses as shown in Figs. 10 (a) and (b) are shown in Fig. 9 (c). It has the same tendency as the orientation characteristics of light sources including LEDs and rotating parabolic mirrors.
実施例 4  Example 4
[0126] 本発明の第一〜第三の実施例においては、 LEDから拡散する光束を平行光に変 換する例を説明してきた。しかしながら、 LEDから拡散する光を照明対象面 (撮像領 域）上に集束させるためには、本発明の第一〜第三の実施例において使用される第 一の集束手段としての回転放物面鏡の回転軸と同軸の回転軸を有する回転楕円面 鏡を用いることもできる。第一の集束手段として回転楕円面鏡を用いる場合には、回 転楕円面鏡の焦点の一方 (例えば、第一焦点 F1)に LEDの発光面を配置すると共 に、回転楕円面鏡の焦点の他方 (例えば、第二焦点 F2)の位置に照明対象面 (撮像 領域)を配置すればよい。そして、この場合には、第二の集束手段を省略することが できる。すなわち、回転楕円面鏡は、本発明の第一〜第三の実施例において使用さ れる第一の集束手段の機能及び第二の集束手段の機能の両方を有し得る。  [0126] In the first to third embodiments of the present invention, the example in which the light beam diffused from the LED is converted into parallel light has been described. However, in order to focus the light diffusing from the LED onto the surface to be illuminated (imaging area), the paraboloid as the first focusing means used in the first to third embodiments of the present invention. A spheroidal mirror having a rotation axis coaxial with the rotation axis of the mirror can also be used. When a spheroid mirror is used as the first focusing means, the LED light emitting surface is arranged at one of the focal points of the spheroid mirror (for example, the first focus F1) and the focus of the spheroid mirror is used. What is necessary is just to arrange | position an illumination object surface (imaging area | region) in the position of the other (for example, 2nd focus F2). In this case, the second focusing means can be omitted. That is, the spheroid mirror can have both the function of the first focusing means and the function of the second focusing means used in the first to third embodiments of the present invention.
[0127] 図 11は、本発明の第四の実施例による照明装置の一つの例を説明する図である。  FIG. 11 is a view for explaining one example of a lighting device according to the fourth embodiment of the present invention.
図 11 (a)は、本発明の第四の実施例による照明装置の一つの例の正面図であり、図 1 Kb)は、副走査方向（Sy)における、本発明の第四の実施例による照明装置の一 つの例によって与えられる照度分布を示す図である。  FIG. 11 (a) is a front view of one example of a lighting device according to the fourth embodiment of the present invention, and FIG. 1 Kb) shows the fourth embodiment of the present invention in the sub-scanning direction (Sy). It is a figure which shows the illumination intensity distribution given by one example of the illuminating device by.
[0128] 図 11 (a)に示す照明装置の例においては、 LED (1)及び回転楕円面鏡（2b)を含 む光源を用いており、 LED (l)の発光面の中心が、回転楕円面鏡（2b)の第 1焦点 F 1に配置されている。また、照明対象面 (撮像領域） (Ai)は、回転楕円面鏡（2b)の第 二の焦点 F2に配置されている。 LED (1)から放出された光は、回転楕円面鏡（2b) によって反射され、照明レンズ (3)に入射する。回転楕円面鏡（2b)によって反射され た光は、主走査方向（Sx)においては、照明レンズ (3)によって拡散させられる一方、 副走査方向（Sy)においては、照明レンズ (3)をそのまま通過し、照明対象面 (撮像 領域）（Ai)における第二焦点の位置に集束する。その結果、図 11 (b)に示すように、 副走査方向（Sy)における照明対象面（撮像領域） (Ai)での照度分布（Each— Di) ( Total— Di)は、図 5 (d)において二点鎖線で示した照度分布と同様のものとなる。  [0128] In the example of the illumination device shown in Fig. 11 (a), a light source including an LED (1) and a spheroidal mirror (2b) is used, and the center of the light emitting surface of the LED (l) is rotated. It is located at the first focal point F1 of the ellipsoidal mirror (2b). The illumination target surface (imaging region) (Ai) is disposed at the second focal point F2 of the spheroid mirror (2b). The light emitted from the LED (1) is reflected by the spheroid mirror (2b) and enters the illumination lens (3). The light reflected by the spheroid mirror (2b) is diffused by the illumination lens (3) in the main scanning direction (Sx), while it passes through the illumination lens (3) as it is in the sub-scanning direction (Sy). Passes and converges to the position of the second focal point on the illumination target surface (imaging area) (Ai). As a result, as shown in Fig. 11 (b), the illuminance distribution (Each—Di) (Total—Di) on the illumination target surface (imaging area) (Ai) in the sub-scanning direction (Sy) is ) Is the same as the illuminance distribution indicated by the two-dot chain line.
[0129] 図 12は、本発明の第四の実施例による照明装置の別の例を説明する図である。図  FIG. 12 is a diagram for explaining another example of the lighting apparatus according to the fourth embodiment of the present invention. Figure
12 (a)は、本発明の第四の実施例による照明装置の別の例の正面図であり、図 12 ( b)は、副走査方向（Sy)における、本発明の第四の実施例による照明装置の別の例 によって与えられる照度分布を示す図である。 12 (a) is a front view of another example of the lighting device according to the fourth embodiment of the present invention, and FIG. b) is a diagram showing the illuminance distribution given by another example of the illumination device according to the fourth embodiment of the present invention in the sub-scanning direction (Sy).
[0130] 図 12 (a)に示す照明装置の例においては、図 10に示す凸レンズ (フードレンズ）（2 c)の焦点位置を変更することによって、 LED (1)から拡散する光を、照明対象面 (撮 像領域）（Ai)上に集束させて!/、る。  [0130] In the example of the illumination device shown in Fig. 12 (a), the light diffused from the LED (1) is illuminated by changing the focal position of the convex lens (hood lens) (2c) shown in Fig. 10. Focus on the target surface (imaging area) (Ai)!
[0131] すなわち、図 12 (a)に示す照明装置の例においては、 LED (l)及び凸レンズ（2c) を含む光源を用いており、凸レンズ (2c)の焦点距離 fが、  That is, in the example of the illumination device shown in FIG. 12 (a), a light source including an LED (l) and a convex lens (2c) is used, and the focal length f of the convex lens (2c) is
[0132] [数 5] [0132] [Equation 5]
a b a b
[0133] のように、設定されている。ここで、 aは、 LEDの発光面から凸レンズ（2c)の主点まで の距離であり、 bは、凸レンズ (2c)から照明対象面（撮像領域）（Ai)までの距離であ る。 LED (1)から放出された光は、凸レンズ（2c)によって集束させられ、照明レンズ（ 3)に入射する。凸レンズ（2c)によって集束された光は、主走査方向においては、照 明レンズ (3)によって拡散させられる一方、副走査方向（Sy)においては、照明レンズ (3)をそのまま通過し、照明対象面 (撮像領域）（Ai)に集束する。その結果、図 12 (b )に示すように、副走査方向（Sy)における照明対象面 (撮像領域）（Ai)での照度分 布（Each— Di) (Total— Di)は、図 5 (d)において二点鎖線で示した照度分布と同 様のものとなる。 [0133] is set. Here, a is the distance from the light emitting surface of the LED to the principal point of the convex lens (2c), and b is the distance from the convex lens (2c) to the illumination target surface (imaging area) (Ai). The light emitted from the LED (1) is focused by the convex lens (2c) and enters the illumination lens (3). The light focused by the convex lens (2c) is diffused by the illumination lens (3) in the main scanning direction, while passing through the illumination lens (3) as it is in the sub-scanning direction (Sy). Focus on surface (imaging area) (Ai). As a result, as shown in Fig. 12 (b), the illuminance distribution (Each-Di) (Total-Di) on the illumination target surface (imaging area) (Ai) in the sub-scanning direction (Sy) is This is the same as the illuminance distribution shown by the two-dot chain line in d).
[0134] なお、図 11及び図 12に示す照明装置の構成を、図 5〜8に示す照明装置又は画 像読取装置の例に適用することができる。  Note that the configuration of the illumination device shown in FIGS. 11 and 12 can be applied to the examples of the illumination device or the image reading device shown in FIGS.
[0135] 図 13は、本発明の第四の実施例による照明装置及び画像読取装置の一つの例を 説明する図である。図 13 (a)は、本発明の第四の実施例による照明装置の一つの例 を示す図であり、図 13 (b)は、本発明の第四の実施例による画像読取装置の一つの 例を示す図である。 FIG. 13 is a diagram for explaining one example of an illumination device and an image reading device according to the fourth embodiment of the present invention. FIG. 13 (a) is a diagram showing an example of an illumination device according to the fourth embodiment of the present invention, and FIG. 13 (b) is a diagram of one of the image reading devices according to the fourth embodiment of the present invention. It is a figure which shows an example.
[0136] 図 13 (a)に示す照明装置の例は、図 11に示す照明装置の例と同様のものである。  The example of the illumination device shown in FIG. 13 (a) is the same as the example of the illumination device shown in FIG.
図 13 (a)においては、照明装置に加えて、画像読取装置の変向ミラー（12)が描か れている。 [0137] 図 13 (b)は、図 11に示す照明装置の例と同様の照明装置を第一走行体（11)に搭 載した画像読取装置の例を示す。図 13 (b)の二点鎖線で示すように、図 13 (a)に示 す照明装置の照明光軸 (Axl)を折り曲げることなく、その照明装置を読取光軸 (AxR )に対して斜めに配置してもよぐ図 13 (b)の実線で示すように、図 13 (a)に示す照 明装置の照明光軸 (Axl)を、折り曲げミラー（6)によって折り曲げることによって、そ の照明装置を、コンタクトガラス（13)の面と平行に配置してもよい。この場合には、コ ンタクトガラス（13)の面と垂直な方向における画像読取装置の大きさを低減すること ができる。 In FIG. 13 (a), in addition to the illumination device, a turning mirror (12) of the image reading device is depicted. FIG. 13 (b) shows an example of an image reading device in which the same lighting device as the example of the lighting device shown in FIG. 11 is mounted on the first traveling body (11). As shown by the two-dot chain line in Fig. 13 (b), the illumination device shown in Fig. 13 (a) is tilted with respect to the reading optical axis (AxR) without bending the illumination optical axis (Axl). As shown by the solid line in FIG. 13 (b), the illumination optical axis (Axl) of the illumination device shown in FIG. 13 (a) is bent by the folding mirror (6), so that The lighting device may be arranged parallel to the surface of the contact glass (13). In this case, the size of the image reading device in the direction perpendicular to the surface of the contact glass (13) can be reduced.
[0138] 図 14は、本発明の第四の実施例による照明装置及び画像読取装置の別の例を説 明する図である。図 14 (a)は、本発明の第四の実施例による照明装置の別の例を示 す図であり、図 14 (b)は、本発明の第四の実施例による画像読取装置の別の例を示 す図である。  FIG. 14 is a diagram for explaining another example of the illumination device and the image reading device according to the fourth embodiment of the present invention. FIG. 14 (a) is a diagram showing another example of an illuminating device according to the fourth embodiment of the present invention, and FIG. 14 (b) shows another example of the image reading device according to the fourth embodiment of the present invention. FIG.
[0139] 図 14 (a)に示す照明装置の例は、図 12に示す照明装置の例と同様のものである。  [0139] The example of the illumination device shown in FIG. 14 (a) is the same as the example of the illumination device shown in FIG.
図 14 (a)においては、照明装置に加えて、画像読取装置の変向ミラー（12)が描か れている。  In FIG. 14 (a), the turning mirror (12) of the image reading device is drawn in addition to the illumination device.
[0140] 図 14 (b)は、図 12に示す照明装置の例と同様の照明装置を第一走行体（11)に搭 載した画像読取装置の例を示す。図 14 (b)の二点鎖線で示すように、図 14 (a)に示 す照明装置の照明光軸 (Axl)を折り曲げることなく、その照明装置を読取光軸 (AxR )に対して斜めに配置してもよぐ図 14 (b)の実線で示すように、図 14 (a)に示す照 明装置の照明光軸 (Axl)を、折り曲げミラー（6)によって折り曲げることによって、そ の照明装置を、コンタクトガラス（13)の面と平行に配置してもよい。この場合には、コ ンタクトガラス（13)の面と垂直な方向における画像読取装置の大きさを低減すること ができる。  FIG. 14 (b) shows an example of an image reading device in which a lighting device similar to the example of the lighting device shown in FIG. 12 is mounted on the first traveling body (11). As shown by the two-dot chain line in FIG. 14 (b), the illumination device shown in FIG. 14 (a) is tilted with respect to the reading optical axis (AxR) without bending the illumination optical axis (Axl). As shown by the solid line in FIG. 14 (b), the illumination optical axis (Axl) of the illumination device shown in FIG. 14 (a) is bent by the folding mirror (6), so that The lighting device may be arranged parallel to the surface of the contact glass (13). In this case, the size of the image reading device in the direction perpendicular to the surface of the contact glass (13) can be reduced.
[0141] なお、図 13及び図 14に示す画像読取装置の例においても、図 7に示すように、光 束を読取光軸 (AxR)の前後で分割し、読取光軸 (AxR)の前後の両方から、分割さ れた光束を用いて、撮像領域 (Ai)を照明することができる。  [0141] In the example of the image reading apparatus shown in Figs. 13 and 14, as shown in Fig. 7, the light flux is divided before and after the reading optical axis (AxR), and before and after the reading optical axis (AxR). In both cases, the imaging region (Ai) can be illuminated using the divided light flux.
実施例 5  Example 5
[0142] ここで、モノクロ原稿用の画像読取装置及びカラー原稿用画像読取装置における L EDの発光色を説明する。 [0142] Here, L in the image reading apparatus for monochrome originals and the image reading apparatus for color originals The ED emission color will be described.
[0143] モノクロ原稿用の画像読取装置においては、光の三原色の青色（B)、緑色（G)、赤 色（R)のいずれかの色の光を発生させる LEDを用いることができる。あるいは、白色In an image reading apparatus for a monochrome document, an LED that generates light of any one of the three primary colors of blue (B), green (G), and red (R) can be used. Or white
LEDを用いることもできる。し力もながら、緑色は、人間の視感度をほぼ代表している ので、緑色の LEDを用いることが好ましい。 LEDs can also be used. However, it is preferable to use a green LED because green is almost representative of human visibility.
[0144] カラー原稿用の画像読取装置においては、カラー用の一次元撮像素子及び白色 L[0144] In an image reading apparatus for color originals, a color one-dimensional image sensor and white L
EDを用いれば、図 5〜図 14に示す照明装置及び画像読取装置を用レ、ること力 Sでき Using ED, it is possible to use the lighting device and the image reading device shown in FIGS.
[0145] R、 G、 B三原色の LEDの各々を用いる場合には、図 5〜図 14に示す照明装置及 び画像読取装置にぉレヽて、青色（B)、緑色（G)、赤色 (R)の LEDを、組み合わせて 又は交互に配置すると共に、カラー用の一次元撮像素子を用いればよい。例えば、 図 5〜図 14に示す照明装置及び画像読取装置において、 LEDの Ll、 L4、 L7 ' ' -と して青色 LEDを配置し、 LEDの L2、 L5、 L8 · · ·として緑色 LEDを配置し、 LEDの L 3、 L6、 L9 ' · ·として赤色 LEDを配置すればよい。 [0145] When each of the R, G, and B primary color LEDs is used, blue (B), green (G), and red (red) are connected to the illumination device and image reading device shown in FIGS. R) LEDs may be arranged in combination or alternately, and a color one-dimensional image sensor may be used. For example, in the illumination device and the image reading device shown in FIGS. 5 to 14, blue LEDs are arranged as LEDs L1, L4, L7 ''-, and green LEDs are used as LEDs L2, L5, L8. Arrange and arrange red LED as L3, L6, L9 '... of LED.
[0146] この場合には、照明対象面（撮像領域）における照度分布に寄与する LEDの数は 、単色の場合と比較して、三分の一に減少する（例えば、図 5において、 6倍を超える ゲイン Qが 2倍程度に減少する）ので、照明対象面（撮像領域）における各色の光に よる照度分布の特性は悪化することになる。そこで、照明レンズの焦点距離 fを短くす る及び/又は照明レンズから照明対象面 (撮像領域)までの距離 gを長くすることによ つて、ゲイン Qを約 3倍程度増加させれば、単色の LEDを用いる場合における照度 分布と同程度に良好な照度分布を得ることができる。  [0146] In this case, the number of LEDs that contribute to the illuminance distribution on the illumination target surface (imaging area) is reduced to one-third compared to the case of a single color (for example, 6 times in FIG. 5). Therefore, the characteristics of the illuminance distribution due to the light of each color on the illumination target surface (imaging area) will deteriorate. Therefore, if the gain Q is increased approximately 3 times by shortening the focal length f of the illumination lens and / or increasing the distance g from the illumination lens to the illumination target surface (imaging area), a single color is obtained. An illuminance distribution that is as good as the illuminance distribution in the case of using an LED can be obtained.
[0147] 図 15は、本発明の第五の実施例による照明方法及び照明装置の例を説明する図 である。 図 15 (a)は、本発明の第五の実施例による照明装置の例の上面図であり、 図 15 (b)は、本発明の第五の実施例による照明装置の例の正面図である。また、図 5 (c)は、本発明の第五の実施例による照明方法の例によって得られる照明対象面（ 撮像領域） (Ai)上での主走査方向（Sx)の照度分布（Each— Di) (Total— Di)を示 す図であり、図 5 (d)は、本発明の第五の実施例による照明方法の例によって得られ る照明対象面 (撮像領域） (Ai)上での副走査方向（Sy)の照度分布を示す図である 〇 FIG. 15 is a diagram for explaining an example of the illumination method and illumination apparatus according to the fifth embodiment of the present invention. FIG. 15 (a) is a top view of an example of a lighting device according to the fifth embodiment of the present invention, and FIG. 15 (b) is a front view of an example of the lighting device according to the fifth embodiment of the present invention. is there. FIG. 5 (c) shows the illuminance distribution (Each— in the main scanning direction (Sx) on the illumination target surface (imaging region) (Ai) obtained by the illumination method example according to the fifth embodiment of the present invention. Di) (Total—Di), and FIG. 5 (d) shows the illumination target surface (imaging area) (Ai) obtained by the example of the illumination method according to the fifth embodiment of the present invention. It is a figure which shows the illumination intensity distribution of the subscanning direction (Sy) of Yes
[0148] 図 15に示すような照明装置の例は、赤 (R)、緑 (G)、青（B)三色の LEDチップ（1) に一括して凸レンズ (2c)のフードレンズを取り付けた光源を含むカラー用照明装置 の例である。図 15に示す照明装置の例では、図 5に示した照明装置における LED 及び回転放物面鏡を含む光源の代わりに、 LEDチップ（1)及び凸レンズ（2c)を含 む光源を使用する。ここで、一つの光源は、青色（B)、緑色（G)、赤色 (R)用の三種 類の LEDチップ（1)を一列に（図 15においては主走査方向に）配置し、一列に配置 された三種類の LEDチップ（1)の全体力 凸レンズ（2c)であるフードレンズで覆わ れている。三色の LEDチップ（1)の配置の順番は、特に限定されないが、図 15にお いては、緑色（G)の LEDチップ（1)を中央に配置し、緑色（G)の LEDチップ（1)に 隣接して、青色の LEDチップ（1)及び赤色の LEDチップ（1)が、配置される。  [0148] In the example of the lighting device shown in Fig. 15, the hood lens of the convex lens (2c) is attached to the red (R), green (G), and blue (B) three-color LED chips (1). This is an example of a color lighting device including a light source. In the example of the illuminating device shown in FIG. 15, a light source including an LED chip (1) and a convex lens (2c) is used instead of the light source including the LED and the rotating parabolic mirror in the illuminating device shown in FIG. Here, one light source has three types of LED chips (1) for blue (B), green (G), and red (R) arranged in a row (in the main scanning direction in FIG. 15) and arranged in a row. The total power of the three types of LED chips (1) is covered with a hood lens that is a convex lens (2c). The order of arrangement of the three-color LED chips (1) is not particularly limited. In FIG. 15, the green (G) LED chip (1) is arranged in the center and the green (G) LED chip ( Adjacent to 1), a blue LED chip (1) and a red LED chip (1) are arranged.
[0149] ここで、三色（B、 G、 R)の LEDチップ（1)及び凸レンズ（2c)を含む単一の光源 L k に起因する、照明対象面（撮像領域）（Ai)での照度分布（Each— Di) (Total— Di) を説明する。なお、凸レンズ（2c)の焦点距離 fは、凸レンズ（2c)の主点から LEDチッ プ（1)までの距離 aに等しいもの（f = a)とする。  [0149] Here, the illumination target surface (imaging area) (Ai) caused by the single light source L k including the LED chip (1) of three colors (B, G, R) and the convex lens (2c) Illuminance distribution (Each—Di) (Total—Di) will be described. The focal length f of the convex lens (2c) is assumed to be equal to the distance a from the principal point of the convex lens (2c) to the LED chip (1) (f = a).
[0150] 図 15に示すような照明装置の例において、緑色（G)の LEDチップ（1)からの発生 する緑色の光束の光軸は、凸レンズ（2c)の光軸と一致しているので、緑色（G)の LE Dチップ（1)からの発生する緑色の光束は、図 5における LEDから発生する光束と全 く同様の振る舞い示す。そして、主走査方向においては、照明レンズ (3)を構成する シリンダレンズの幅、すなわち、光源の幅に対して、  [0150] In the example of the illumination device as shown in Fig. 15, the optical axis of the green luminous flux generated from the green (G) LED chip (1) coincides with the optical axis of the convex lens (2c). The green luminous flux generated from the green (G) LED chip (1) behaves exactly the same as the luminous flux generated from the LED in Fig. 5. In the main scanning direction, the width of the cylinder lens constituting the illumination lens (3), that is, the width of the light source,
[0151] [数 6]  [0151] [Equation 6]
0 = (g - f) 0 = (g-f)
f  f
[0152] 倍の幅の緑色の光束で、照明対象面 (撮像領域）（Ai)を照射する。なお、本発明の 実施形態においては、 Qのィ直は、 2以上である。 [0152] The illumination target surface (imaging region) (Ai) is irradiated with a green light beam having a double width. In the embodiment of the present invention, the Q length is 2 or more.
[0153] 赤色（R)の LEDチップ（1)から発生する赤色の光束の光軸は、凸レンズ（2c)の光 軸から若干下側にずれているので、赤色（R)の LEDチップ（1)から発生する赤色の 光束は、凸レンズ（2c)を通過し、緑色（G)の LEDチップ（1)から発生する緑色の光 束よりも若干上側にずれて、照明対象面 (撮像領域）（Ai)を照射する。照明レンズ (3 )を構成するシリンダレンズの幅、すなわち、光源の幅に対する、照明対象面 (撮像領 域）（Ai)における赤色の光束の幅の比 Qは、緑色（G)の LEDチップ（1)から発生す る緑色の光束についての値と同じである。 [0153] Since the optical axis of the red light flux generated from the red (R) LED chip (1) is slightly shifted from the optical axis of the convex lens (2c), the red (R) LED chip (1 ), The red light beam that passes through the convex lens (2c) and the green light generated from the green (G) LED chip (1). Illuminate the illumination target surface (imaging area) (Ai) slightly above the bundle. The ratio of the width of the red luminous flux in the illumination target surface (imaging area) (Ai) to the width of the cylinder lens that constitutes the illumination lens (3), that is, the width of the light source Q is the green (G) LED chip ( This is the same as the value for the green luminous flux generated from 1).
[0154] 青色（B)の LEDチップ（1)から発生する青色の光束の光軸は、凸レンズ（2c)の光 軸から若干上側にずれているので、青色（B)の LEDチップ（1)から発生する青色の 光束は、凸レンズ（2c)を通過し、緑色（G)の LEDチップ（1)から発生する緑色の光 束よりも若干下側にずれて、照明対象面 (撮像領域）（Ai)を照射する。照明レンズ (3 )を構成するシリンダレンズの幅、すなわち、光源の幅に対する、照明対象面 (撮像領 域）（Ai)における青色の光束の幅の比 Qは、緑色（G)の LEDチップ（1)から発生す る緑色の光束についての値と同じである。  [0154] The optical axis of the blue luminous flux generated from the blue (B) LED chip (1) is slightly shifted from the optical axis of the convex lens (2c), so the blue (B) LED chip (1) The blue luminous flux generated from the lens passes through the convex lens (2c) and is slightly below the green light flux generated from the green (G) LED chip (1), and the illumination target surface (imaging area) ( Irradiate Ai). The ratio of the width of the blue luminous flux in the illumination target surface (imaging area) (Ai) to the width of the cylinder lens that constitutes the illumination lens (3), that is, the width of the light source Q is the green (G) LED chip ( This is the same as the value for the green luminous flux generated from 1).
[0155] なお、図 15においては、光源し力も発生する赤色の光束を、太い破線で示し、緑 k  [0155] In Fig. 15, the red luminous flux that is a light source and generates a force is indicated by a thick broken line, and green k
色の光束を、実線で示し、青色の光束を、細い破線で示している。その三色のそれ ぞれの光束による照明対象面 (撮像領域） (Ai)での照度分布の概念を個別の照度 分布（Each Di)として図 15 (c)に示す。また、他の光源 、L 、L 、 L  The colored luminous flux is indicated by a solid line, and the blue luminous flux is indicated by a thin broken line. The concept of the illuminance distribution on the illumination target surface (imaging area) (Ai) for each of the three colors is shown as an individual illuminance distribution (Each Di) in Fig. 15 (c). Also, other light sources, L, L, L
― k 2 k— 1 k+ 1 k ― K 2 k— 1 k + 1 k
• ·など力 発生する光束も同様に照明対象面 (撮像領域）（Ai)を照射するので、• Since the luminous flux generated by the force also illuminates the illumination target surface (imaging area) (Ai),
+ 2 + 2
光源しの光軸上における照明対象面（撮像領域）（Ai)での照度には、光源しの周 k k 囲の光源から発生する光束の照度も寄与する。それらの光源の全体に起因する全体 の照度分布 (Total— Di)もまた図 15 (c)に示す。  The illuminance on the illumination target surface (imaging area) (Ai) on the optical axis of the light source also contributes to the illuminance of the luminous flux generated from the light source in the circumference k k of the light source. The total illuminance distribution (Total—Di) due to the whole of these light sources is also shown in Fig. 15 (c).
[0156] 以上のように、三色の LEDチップ（1)及び凸レンズ（2c)を含む光源を使用する場 合にも、主走査方向における、各色の光束によって照明される照明対象面（撮像領 域）（Ai)での照度ムラは、各色の光束毎に、図 5に示すような照度ムラを適用すること によって、説明される。 [0156] As described above, even when a light source including three-color LED chips (1) and a convex lens (2c) is used, an illumination target surface (imaging area) illuminated by light beams of each color in the main scanning direction. The illuminance unevenness in the area (Ai) is explained by applying the illuminance unevenness shown in FIG. 5 for each color beam.
[0157] 次に、副走査方向（Sy)については、青色（B)、緑色（G)、赤色（R)の LEDチップ（  [0157] Next, in the sub-scanning direction (Sy), blue (B), green (G), and red (R) LED chips (
1)は、同一の光軸上に存在し、凸レンズの焦点距離 fは、 f = aを満たすので、各色の LED (1)から発生する光束は、凸レンズ (2c)を通過し、概略平行光となる。  1) exists on the same optical axis, and the focal length f of the convex lens satisfies f = a, so that the light flux generated from the LED (1) of each color passes through the convex lens (2c) and is approximately parallel light It becomes.
[0158] ここで、図 15に示す照明装置が、集束レンズ (4a)を含まない場合には、照明レン ズ (3)を通過した各色の平行光束が、そのまま照明対象面 (撮像領域）（Ai)を照射 する。その結果、副走査方向（Sy)における照明対象面 (撮像領域）（Ai)での照度分 布（Di)は、図 15 (d)の実線で示すように、ブロードな分布となる。一方、図 15に示す 照明装置が、照明レンズ (3)と照明対象面 (撮像領域）（Ai)との間に設けられ且つ照 明対象面 (撮像領域）（Ai)力 焦点距離 Fだけ離れた位置に配置される集束レンズ（ 4a)を含む場合には、照明レンズ (3)を通過した各色の平行光束は、照明対象面（撮 像領域）（Ai)上に集束する。その結果、副走査方向（Sy)における照明対象面 (撮像 領域）（Ai)での照度分布は、図 15 (d)の二点鎖線で示すように、シャープな分布（E ach_Di) (Total— Di)となる。 [0158] Here, when the illumination device shown in Fig. 15 does not include the focusing lens (4a), the parallel luminous flux of each color that has passed through the illumination lens (3) remains as it is as the illumination target surface (imaging region) ( Ai) To do. As a result, the illuminance distribution (Di) on the illumination target surface (imaging region) (Ai) in the sub-scanning direction (Sy) has a broad distribution as shown by the solid line in FIG. On the other hand, the illumination device shown in FIG. 15 is provided between the illumination lens (3) and the illumination target surface (imaging region) (Ai) and is illuminated by the illumination target surface (imaging region) (Ai) force focal length F. In the case where the focusing lens (4a) disposed at the position is included, the parallel luminous flux of each color that has passed through the illumination lens (3) is focused on the illumination target surface (image area) (Ai). As a result, the illuminance distribution on the illumination target surface (imaging area) (Ai) in the sub-scanning direction (Sy) has a sharp distribution (Each_Di) (Total— Di).
[0159] なお、副走査方向（Sy)において、 LEDチップ（1)から発生する光を照明対象面（ 撮像領域）（Ai)上に集束させる手段としては、凸レンズ (2c)の焦点距離 fを、図 12に おける照明装置の例と同様に、  [0159] As a means for focusing light generated from the LED chip (1) on the illumination target surface (imaging region) (Ai) in the sub-scanning direction (Sy), the focal length f of the convex lens (2c) is set as follows. Similar to the example of the lighting device in FIG.
[0160] [数 7]  [0160] [Equation 7]
a b a b
[0161] とする方法が挙げられる。ここで、 aは、 LEDチップ（1)の発光面から凸レンズ（2c)の 主点までの距離であり、 bは、凸レンズ (2c)の主点から照明対象面 (撮像領域） (Ai) までの距離である。そして、この場合には、集束レンズ (4a)を設けることを必要としな い。 [0161] can be mentioned. Here, a is the distance from the light emitting surface of the LED chip (1) to the principal point of the convex lens (2c), and b is from the principal point of the convex lens (2c) to the illumination target surface (imaging area) (Ai). Is the distance. In this case, it is not necessary to provide the focusing lens (4a).
[0162] 図 15に示すような照明装置を、画像読取装置の第一走行体に搭載する場合には、 図 15に示すような照明装置を、図 6〜図 8に示すような画像読取装置に適用すること ができる。  When the illumination device as shown in FIG. 15 is mounted on the first traveling body of the image reading device, the illumination device as shown in FIG. 15 is replaced with the image reading device as shown in FIGS. It can be applied to.
実施例 6  Example 6
[0163] 図 16は、本発明の第六の実施例による照明方法及び画像読取装置の例を説明す る図である。 図 16 (a)は、本発明の第六の実施例による画像読取装置の例の上面 図であり、図 16 (b)は、本発明の第六の実施例による画像読取装置の例の正面図で ある。また、図 16 (c)は、本発明の第六の実施例による照明方法の例によって得られ る照明対象面 (撮像領域)上での副走査方向の照度分布を示す図である。 [0164] 図 16に示すような画像読取装置の例は、赤 (R)、緑 (G)、青（B)三色の LEDチッ プ（1 )に一括して凸レンズ（2c)のフードレンズを取り付けた光源を用いるカラー画像 読取装置の例である。 FIG. 16 is a view for explaining an example of the illumination method and the image reading apparatus according to the sixth embodiment of the present invention. FIG. 16A is a top view of an example of the image reading apparatus according to the sixth embodiment of the present invention, and FIG. 16B is a front view of the example of the image reading apparatus according to the sixth embodiment of the present invention. It is a figure. FIG. 16 (c) is a diagram showing the illuminance distribution in the sub-scanning direction on the illumination target surface (imaging area) obtained by the example of the illumination method according to the sixth embodiment of the present invention. [0164] An example of an image reading apparatus as shown in Fig. 16 is a hood lens with a convex lens (2c) in a batch of three red LED chips (1) of red (R), green (G), and blue (B). 1 is an example of a color image reading apparatus using a light source with a light attached.
[0165] 図 16に示すような画像読取装置の例においては、照明系の三色の LEDチップ（1 ) の配置が、各色の画像を読み取るための読取系の一次元撮像素子（1 5)の配置と対 応付けられる。図 16に示すような画像読取装置において、照明対象面 (撮像領域） ( Ai)より左側の系が、照明系であり、照明対象面 (撮像領域）（Ai)より右側の系が、読 取系である。そして、照明系を用いて、撮像領域 (Ai)を照明し、撮像領域 (Ai)に置 かれた原稿の画像を、読取系で読み取る。  In the example of the image reading apparatus as shown in FIG. 16, the arrangement of the three-color LED chips (1) of the illumination system is such that the one-dimensional imaging element (15) of the reading system for reading the image of each color Can be associated with In the image reading apparatus as shown in FIG. 16, the system on the left side of the illumination target surface (imaging region) (Ai) is the illumination system, and the system on the right side of the illumination target surface (imaging region) (Ai) is the reading system. It is a system. Then, the imaging area (Ai) is illuminated using the illumination system, and the image of the original placed in the imaging area (Ai) is read by the reading system.
[0166] カラー画像読取装置の読取系では、三本の 1ライン CCD (—次元撮像素子（1 5) ) を並列させた 3ライン CCDを用いる。三本の 1ライン CCDの各々には、赤色（R)、緑 色（G)、又は青色（B)を透過するカラーフィルター（18)が設けられ、三本の 1ライン CCDの各々は、カラーフィルター（18)を透過する色の画像を読み取る。このような力 ラーフィルター（18 )を備えた 3ライン CCDは、原稿における撮像領域 (Ai)の同じ場 所の画像を同時に読み取ることができない。現行の画像読取装置においては、 600 dpiの画像を構成する画素のサイズは、 42. 3 mである力 現行の画像読取装置の 読取系は、縮小光学系であり、撮像素子においては、読取系の縮小率に応じて、 10 μ ΐη、 7 ii m、又は 4 · 7 mなどに相当する。しかしながら、このような短い間隔で 1ラ イン CCDを配列させることは困難である。実際には、三本の 1ライン CCDを、副走査 方向（Sy)に並べる場合には、三本の 1ライン CCDを、 3画素〜 4画素に相当する距 離だけ、互いに離す必要がある。ここで、三本の 1ライン CCDの間隔は、原稿面の撮 像領域 (Ai)では、おおよそ、 0. 4〜0. 2mmに相当する。すなわち、原稿面の撮像 領域 (Ai)において、 0. 4〜0. 2mmの間隔で、赤色、緑色、及び青色の画像を読み 取ることになる。よって、赤色、緑色、及び青色の LEDチップ（1 )から発生する赤色、 緑色、及び青色の光束を、原稿面の撮像領域 (Ai)において、 0. 4〜0. 2mmの間 隔で照射することが好ましい。  [0166] The reading system of the color image reading apparatus uses a three-line CCD in which three one-line CCDs (-dimensional imaging device (15)) are arranged in parallel. Each of the three 1-line CCDs is provided with a color filter (18) that transmits red (R), green (G), or blue (B). Read the color image that passes through the filter (18). A three-line CCD equipped with such a power color filter (18) cannot simultaneously read images at the same location in the imaging area (Ai) of the document. In the current image reading device, the size of the pixel constituting the 600 dpi image is 42.3 m. The reading system of the current image reading device is a reduction optical system, and in the image sensor, the reading system is Corresponds to 10 μΐη, 7 ii m, or 4 · 7 m, depending on the reduction ratio. However, it is difficult to arrange 1-line CCDs at such short intervals. Actually, when three 1-line CCDs are arranged in the sub-scanning direction (Sy), the three 1-line CCDs need to be separated from each other by a distance corresponding to 3 to 4 pixels. Here, the interval between the three 1-line CCDs is roughly equivalent to 0.4 to 0.2 mm in the image area (Ai) on the document surface. That is, red, green, and blue images are read at intervals of 0.4 to 0.2 mm in the imaging area (Ai) on the original surface. Therefore, the red, green, and blue light fluxes generated from the red, green, and blue LED chips (1) are irradiated at intervals of 0.4 to 0.2 mm in the imaging area (Ai) of the document surface. It is preferable.
[0167] ここで、副走査方向（Sy)において、照明系の三色の LEDチップ（1 )の配置と照明 対象面（撮像領域）（Ai)における各色の光束の中心位置との関係を、図 16 (b)に示 す。図 16(b)において、 aは、 LEDチップの発光面から凸レンズ（2c)の主点までの 距離であり、 bは、凸レンズ（2c)の主点から集束レンズ (4a)の主点までの距離であり 、 cは、集束レンズ (4a)の主点から照明対象面 (撮像領域）（Ai)までの距離である。 また、 mOは、各色の LEDチップ（1)間の間隔であり、 mlは、集束レンズ（4a)を通過 する各色の LEDチップ（1)からの各色の光束の中心間距離であり、 m2は、照明対 象面（撮像領域） (Ai)における各色の LEDチップ（1)からの各色の光束の中心間距 離である。さらに、凸レンズ (2c)部の焦点距離を fOとし、集束レンズ (4a)の焦点距離 を flとすると、 fO = a及び fl=cであるため、 [0167] Here, in the sub-scanning direction (Sy), the relationship between the arrangement of the three-color LED chip (1) of the illumination system and the center position of the luminous flux of each color on the illumination target surface (imaging area) (Ai) Shown in Fig. 16 (b) The In Fig. 16 (b), a is the distance from the light emitting surface of the LED chip to the principal point of the convex lens (2c), and b is the distance from the principal point of the convex lens (2c) to the principal point of the focusing lens (4a). C is the distance from the principal point of the focusing lens (4a) to the illumination target surface (imaging area) (Ai). MO is the distance between the LED chips (1) of each color, ml is the distance between the centers of the light fluxes of each color from the LED chips (1) of each color passing through the focusing lens (4a), and m2 is The distance between the centers of the luminous flux of each color from the LED chip (1) of each color on the illumination target surface (imaging area) (Ai). Furthermore, if the focal length of the convex lens (2c) is fO and the focal length of the focusing lens (4a) is fl, then fO = a and fl = c,
[0168] [数 8] ml =—xmO (at f0 = a) ■ · · (1： a  [0168] [Equation 8] ml = —xmO (at f0 = a) ■ · · (1: a
c . -i b  c .-i b
ml = m\ + cx tan tan tan —— (at fl = c) ' ' · (2)  ml = m \ + cx tan tan tan —— (at fl = c) '' · (2)
ml m\  ml m \
[0169] の関係が成り立つ。よって、式（1)及び（2)より、 The relationship [0169] holds. Therefore, from equations (1) and (2)
[0170] [数 9] [0170] [Equation 9]
_, axc _ι a _, axc _ι a
m2 =— X mO + x tan tan tan (at f0 = a \ = c) (3)  m2 = — X mO + x tan tan tan (at f0 = a \ = c) (3)
a bxmO mO  a bxmO mO
[0171] の関係が成り立つ。 The relationship [0171] holds.
[0172] 式（2)より、 b = cのとき、 m2 = mlであり、さらに、 b<cのとき、 m2〉mlであり、 b〉 cのとき、 m2<mlである。  [0172] From equation (2), m2 = ml when b = c, m2> ml when b <c, and m2 <ml when b> c.
[0173] また、式（3)より、 b = cのとき、 [0173] From equation (3), when b = c,
[0174] [数 10] m2 =— xmQ [0174] [Equation 10] m2 = — xmQ
a  a
[0175] であり、さらに、 bく cのとき、 [0175] and when b and c,
[0176] [数 11] [0176] [Equation 11]
^ b ^ ^ b ^
m2>— xmO  m2> — xmO
a [0177] であり、 b〉cのとき、 a [0177] When b> c,
[0178] [数 12] mlく ~ mQ [0178] [Equation 12] ml ~ mQ
a  a
[0179] である。 [0179]
[0180] なお、図 16 (b)においては、 fO = a及び fl =cであり、且つ、 b = cである。図 16 (a) 及び (b)に示す画像読取装置における副走査方向（Sy)の照度分布を図 16 (c)に示 すが、実際には、照明系の構成要素の配置を考慮しながら、上記のような関係を保 つことによって、各色の光束によって照明される照明対象面 (撮像領域）（Ai)での照 度分布（Di)のピーク力 S、各色の画像を読み取る 1ライン CCDの位置に対応するよう に、照明系の設計をすることができる。  In FIG. 16 (b), fO = a and fl = c, and b = c. Fig. 16 (c) shows the illuminance distribution in the sub-scanning direction (Sy) of the image reading device shown in Figs. 16 (a) and 16 (b). By maintaining the above relationship, the peak power S of the illumination distribution (Di) on the illumination target surface (imaging area) (Ai) illuminated by the light flux of each color, and the 1-line CCD that reads the image of each color The lighting system can be designed so as to correspond to the position of.
[0181] また、 R、 G、 Bの色の配置は、主走査方向（Sx)又は副走査方向（Sy)における直 線上にあることを仮定した力 S、 R、 G、 Bの色の配置は、特に限定されず、例えば、 R、 G、 Bの色は、三角形の各頂点、ひらがなの「く」の字状、英文字の「L」の字状に配置 されることもある。そのような場合には、図 15及び図 16に示すような考え方を組み合 わせることによって、照明装置及び画像読取装置の最適設計が可能となる。  [0181] Also, the arrangement of the colors R, G, B is assumed to be on a straight line in the main scanning direction (Sx) or the sub-scanning direction (Sy). The arrangement of the colors S, R, G, B There is no particular limitation, and for example, the colors of R, G, and B may be arranged at the vertices of a triangle, the letter “K” in hiragana, or the letter “L” in English. In such a case, an optimum design of the illumination device and the image reading device can be achieved by combining the ideas as shown in FIGS.
実施例 7  Example 7
[0182] 図 17は、本発明の第七の実施例による照明方法及び照明装置の一つの例を説明 する図である。図 17 (a)は、本発明の第七の実施例による照明装置の一つの例の斜 視図であり、図 17 (b)は、本発明の第七の実施例による画像読取装置の一つの例の 正面図であり、図 17 (c)は、本発明の第七の実施例による画像読取装置の例の一つ の側面図である。また、図 17 (d)は、本発明の第七の実施例による照明方法の例の 一つによって得られる照明対象面 (撮像領域)上での主走査方向の照度分布を示す 図である。  FIG. 17 is a view for explaining one example of the illumination method and illumination apparatus according to the seventh embodiment of the present invention. FIG. 17 (a) is a perspective view of an example of an illuminating device according to the seventh embodiment of the present invention, and FIG. 17 (b) is an image reading device according to the seventh embodiment of the present invention. FIG. 17 (c) is a side view of one example of an image reading apparatus according to the seventh embodiment of the present invention. FIG. 17 (d) is a diagram showing the illuminance distribution in the main scanning direction on the illumination target surface (imaging region) obtained by one of the illumination methods according to the seventh embodiment of the present invention.
[0183] 図 17に示すような照明装置の例では、長方形の発光面を備えた複数の LED (1)を 用いる。また、図 17に示すような照明装置の例は、長方形の発光面を備えた複数の LED (1)と照明対象領域 (Ai)との間に、主走査方向（Sx)において長方形の発光面 を備えた複数の LED (1)から発生する光束を拡散させるシリンダレンズアレイの照明 レンズ (3)を含む。そして、長方形の発光面を備えた複数の LED (1)と照明レンズ (3 )との間に、副走査方向（Sy)にお!/、て長方形の発光面を備えた複数の LED (1)から 発生する光束を集束させるシリンダレンズの集束レンズ (4a)が揷入される。なお、照 シリンダレンズの焦点距離を設定する考え方は、第 1〜第 6の実施例のものと同じで ある。なお、集束レンズ (4a)は、図 17 (c)に示すように集束されるように示しているが 、副走査方向（Sy)において、長方形の発光面を備えた複数の LED (1)から発生す る光束を、必ずしも集束させる必要はなぐ平行光又は拡散光に変換してもよい。さら には、集束レンズ (4a)の揷入は、必ずしも必須ではない。 In the example of the lighting device as shown in FIG. 17, a plurality of LEDs (1) having a rectangular light emitting surface are used. In addition, an example of an illumination device as shown in FIG. 17 is a rectangular light emitting surface in the main scanning direction (Sx) between a plurality of LEDs (1) having a rectangular light emitting surface and an illumination target area (Ai). Cylinder lens array illumination that diffuses the luminous flux generated by multiple LEDs (1) Includes lens (3). Then, between the plurality of LEDs (1) having a rectangular light emitting surface and the illumination lens (3), a plurality of LEDs (1) having a rectangular light emitting surface in the sub-scanning direction (Sy)! ), A focusing lens (4a) for the cylinder lens that focuses the luminous flux generated from the lens is inserted. The concept of setting the focal length of the illumination cylinder lens is the same as that in the first to sixth embodiments. The focusing lens (4a) is shown to be focused as shown in FIG. 17 (c). However, in the sub-scanning direction (Sy), a plurality of LEDs (1) having a rectangular light emitting surface are used. The generated light beam may be converted into parallel light or diffused light that is not necessarily focused. Furthermore, the insertion of the focusing lens (4a) is not always essential.
[0184] また、図 17に示すような照明装置の例では、図 17 (b)に示すように、主走査方向（ Sx)において、長方形の発光面を備えた複数の LED (1)の各々力、ら発生する光束 は、各々の LED (1)に対応する照明レンズ（3)のシリンダレンズに入射するのみなら ず、各々の LED (1)に対応する照明レンズ（3)のシリンダレンズの近傍における（又 はそのシリンダレンズに隣接する)シリンダレンズにも入射する。その結果、長方形の 発光面を備えた複数の LED (1)の各々力 発生する光束は、照明レンズ (3)によつ て、より拡散させられる。例えば、図 17 (b)に示すように、 LED (1)の一つ L4から拡 散する光束は、主として、 LED (1)の L4に対応するシリンダレンズに入射し、予め設 定された倍率で、照明対象面 (撮像領域）（Ai)を照射する。しかしながら、 LED (l) の一つ L4から拡散する光束の一部は、 LED (1)の L4に隣接する LED (1)の L3及 び L5に対応するシリンダレンズにも入射する。さらに、 LED (1)の一つ L4から拡散 する光束の一部は、 LED (l)の L4の近傍に位置する LED (l)の L2及び L6に対応 するシリンダレンズにも入射する。その結果、図 17に示すような照明装置の例では、 LED (1)から発生する光を、より広く拡散させること力 Sできる。  Further, in the example of the illumination device as shown in FIG. 17, as shown in FIG. 17 (b), each of the plurality of LEDs (1) having a rectangular light emitting surface in the main scanning direction (Sx) is provided. The luminous flux generated by the force not only enters the cylinder lens of the illumination lens (3) corresponding to each LED (1), but also the cylinder lens of the illumination lens (3) corresponding to each LED (1). It also enters the cylinder lens in the vicinity (or adjacent to the cylinder lens). As a result, the luminous flux generated by each of the plurality of LEDs (1) having a rectangular light emitting surface is further diffused by the illumination lens (3). For example, as shown in Fig. 17 (b), the light beam diffused from L4 of LED (1) is mainly incident on the cylinder lens corresponding to L4 of LED (1), and has a preset magnification. Then, the surface to be illuminated (imaging area) (Ai) is irradiated. However, a part of the light beam diffused from L4 of LED (l) also enters the cylinder lens corresponding to L3 and L5 of LED (1) adjacent to L4 of LED (1). In addition, a part of the light beam diffused from L4 of LED (1) is also incident on the cylinder lens corresponding to L2 and L6 of LED (l) located near L4 of LED (l). As a result, in the example of the illuminating device as shown in FIG. 17, it is possible to diffuse light S generated from the LED (1) more widely.
[0185] そして、図 17 (a)、（b)及び (c)に示すような照明装置を使用することによって、図 1 7 (d)に示すように、主走査方向（Sx)にお!/、て、複数の LED (1)の発光効率のバラ ツキに起因する、照明対象面 (撮像領域）（Ai)での照度分布の変動を大幅に低減す ること力 Sできる。すなわち、図 4に示すような従来の照明装置では、主走査方向（Sx) において、より低い発光効率を備えた LED (1)によって照明される照明対象面（撮像 領域）（Ai)での照度 h2に対するより高い発光効率を備えた LED (1)によって照明さ れる照明対象面（撮像領域）（Ai)での照度 hiの比が、おおよそ二倍であったとして も、図 17 (a)、 （b)及び (c)に示すような照明レンズ (3)を含む照明装置を使用する場 合には、より低い発光効率を備えた LED (1)によって照明される照明対象面 (撮像 領域）（Ai)での照度 h2'に対するより高い発光効率を備えた LED (1)によって照明 される照明対象面（撮像領域） (Ai)での照度 hi，の比 (hi， /h2' )を、 (hl/h2)よ りも大幅に低減することができる。より具体的には、図 17 (d)中の（Actual— Di2)に 示すように、（hi ' /h2' )の値の変動幅は、 10%程度にまで容易に抑制される。 Then, by using the illumination device as shown in FIGS. 17 (a), (b) and (c), as shown in FIG. 17 (d), the main scanning direction (Sx)! Therefore, it is possible to significantly reduce fluctuations in the illuminance distribution on the illumination target surface (imaging area) (Ai) due to variations in the luminous efficiency of multiple LEDs (1). That is, in the conventional illumination device as shown in FIG. 4, in the main scanning direction (Sx), the illumination target surface illuminated by the LED (1) having lower luminous efficiency (imaging) The ratio of illuminance hi on the illumination target surface (imaging area) (Ai) illuminated by the LED (1) with higher luminous efficiency relative to the illuminance h2 in area (Ai) is approximately double. However, when using an illuminating device including an illumination lens (3) as shown in Fig. 17 (a), (b) and (c), it is illuminated by an LED (1) with a lower luminous efficiency. Ratio of illuminance hi on the illumination target surface (imaging area) (Ai) illuminated by the LED (1) with higher luminous efficiency relative to the illuminance h2 'on the illumination target surface (imaging area) (Ai) ( hi, / h2 ') can be significantly reduced compared to (hl / h2). More specifically, as shown in (Actual-Di2) in Fig. 17 (d), the fluctuation range of the value of (hi '/ h2') is easily suppressed to about 10%.
[0186] 図 17に示すような照明装置においては、主走査方向（Sx)における光束の拡散の 範囲がより広いので、照明装置に側面鏡（5a, 5b)を設けることが効果的である。な お、側面鏡（5a, 5b)は、 LED (1)の側面まで設けることが有効である。この場合には 、 LEDからの拡散光を、主走査方向（Sx)において、照明対象領域 (Ai)の外側に拡 散させることなく、照明対象面 (撮像領域）（Ai)に照射させることができる。  In the illuminating device as shown in FIG. 17, since the range of light beam diffusion in the main scanning direction (Sx) is wider, it is effective to provide side mirrors (5a, 5b) in the illuminating device. It is effective to install the side mirrors (5a, 5b) up to the side of LED (1). In this case, it is possible to irradiate the illumination target surface (imaging region) (Ai) with the diffused light from the LED without diffusing outside the illumination target region (Ai) in the main scanning direction (Sx). it can.
[0187] 図 18は、本発明の第七の実施例による照明装置の別の例を説明する図である。図  FIG. 18 is a diagram for explaining another example of a lighting device according to the seventh embodiment of the present invention. Figure
18 (a) ( 本発明の第七の実施例による照明装置の別の例の上面図であり、図 18 ( b)は、本発明の第七の実施例による画像読取装置の別の例の正面図である。  18 (a) is a top view of another example of an illuminating device according to the seventh embodiment of the present invention, and FIG. 18 (b) is a diagram of another example of the image reading device according to the seventh embodiment of the present invention. It is a front view.
[0188] 図 18に示すような照明装置の例においては、図 17に示すような照明装置の例にお ける集光レンズ (4a)の代わりに、放物面鏡（2d)を用い、光源には、図 17と同じように 長方形の発光面を備えた LEDを並べて用いている。ここで、放物面鏡（2d)は、主走 查方向（Sx)にお!/、て平行平面の断面を有し、副走査方向（Sy)にお!/、て放物面の 断面を有する。  In the example of the illumination device as shown in FIG. 18, a parabolic mirror (2d) is used instead of the condenser lens (4a) in the example of the illumination device as shown in FIG. As shown in Fig. 17, LEDs with rectangular light-emitting surfaces are used side by side. Here, the parabolic mirror (2d) has a parallel plane cross section in the main travel direction (Sx) and a cross section of the paraboloid in the sub-scan direction (Sy)! Have
[0189] また、図 18に示すような照明装置の例においては、主走査方向（Sx)において、複 数の LED (1)の各々力 発生する光束に対する障壁がないので、図 17に示すような 照明装置の例と同様に、各々の LED (1)から発生する光束は各々の LED (1)に対 応する照明レンズ（3)のシリンダレンズに入射するのみならず、各々の LED (1)に対 接する）シリンダレンズにも入射する。その結果、各々の LED (1)から発生する光束 は、照明レンズ (3)によって、より拡散させられる。例えば、 LED (1)の一つ L4から拡 散する光束は、主として、 LED (1)の L4に対応するシリンダレンズに入射し、予め設 定された倍率で、照明対象面 (撮像領域）（Ai)を照射する。しかしながら、 LED (l) の一つ L4から拡散する光束の一部は、 LED (1)の L4に隣接する LED (1)の L3及 び L5に対応するシリンダレンズにも入射する。さらに、 LED (1)の一つ L4から拡散 する光束の一部は、 LED (l)の L4の近傍に位置する LED (l)の L2及び L6に対応 するシリンダレンズにも入射する。その結果、図 18に示すような照明装置の例では、 LED (1)から発生する光を、より広く拡散させること力 Sできる。 Also, in the example of the illumination device as shown in FIG. 18, there is no barrier against the luminous flux generated by each of the plurality of LEDs (1) in the main scanning direction (Sx), so that as shown in FIG. As in the example of the lighting device, the luminous flux generated from each LED (1) not only enters the cylinder lens of the illumination lens (3) corresponding to each LED (1), but also each LED (1 It is also incident on the cylinder lens). As a result, the luminous flux generated from each LED (1) is further diffused by the illumination lens (3). For example, from L4, one of the LEDs (1) The scattered light beam mainly enters the cylinder lens corresponding to L4 of the LED (1), and illuminates the illumination target surface (imaging area) (Ai) at a preset magnification. However, a part of the light beam diffused from L4 of LED (l) also enters the cylinder lens corresponding to L3 and L5 of LED (1) adjacent to L4 of LED (1). In addition, a part of the light beam diffused from L4 of LED (1) is also incident on the cylinder lens corresponding to L2 and L6 of LED (l) located near L4 of LED (l). As a result, in the example of the lighting device as shown in FIG. 18, the force S that diffuses the light generated from the LED (1) more widely can be achieved.
[0190] 図 18に示すような照明装置においては、主走査方向（Sx)における光束の拡散の 範囲がより広いので、照明装置に側面鏡（5a, 5b)を設けることが効果的である。な お、側面鏡（5a, 5b)は、放物面鏡（2d)の側面まで設けることが有効である。この場 合には、 LEDからの拡散光を、主走査方向（Sx)において、照明対象領域 (Ai)の外 側に拡散させることなぐ照明対象面 (撮像領域）（Ai)に照射させることができる。  In the illuminating device as shown in FIG. 18, since the diffusion range of the light flux in the main scanning direction (Sx) is wider, it is effective to provide the side mirrors (5a, 5b) in the illuminating device. It is effective to provide the side mirrors (5a, 5b) up to the side of the parabolic mirror (2d). In this case, it is possible to irradiate the illumination target surface (imaging region) (Ai) without diffusing the diffused light from the LED outside the illumination target region (Ai) in the main scanning direction (Sx). it can.
[0191] 図 18に示す照明装置は、集束レンズ (4a)を含むが、集束レンズ (4a)は、必ずしも 必須の構成要素ではない。図 18に示すような照明装置の例においては、第一の集 束手段として、放物面鏡（2a)を用いている力 S、第一の集束手段としては、楕円面鏡 を用いることもできる。ここで、楕円面鏡は、主走査方向（Sx)においては、平行平面 の断面を有し、副走査方向（Sy)においては、楕円面の断面を有する。そして、楕円 面鏡の楕円面の第一焦点は、 LEDの発光面の中心に位置すると共に、楕円面鏡の 楕円面の第二焦点は、照明対象領域 (Ai)に位置する。第一の集束手段としてこのよ うな楕円面鏡を用いる場合には、集束レンズ (4a)は、不要となる。  [0191] The illumination device shown in FIG. 18 includes a focusing lens (4a), but the focusing lens (4a) is not necessarily an essential component. In the example of the lighting device as shown in FIG. 18, a force S using a parabolic mirror (2a) is used as the first bundling means, and an ellipsoidal mirror is used as the first focusing means. it can. Here, the ellipsoidal mirror has a parallel plane section in the main scanning direction (Sx), and an ellipsoidal section in the sub-scanning direction (Sy). The first focal point of the elliptical surface of the elliptical mirror is located at the center of the light emitting surface of the LED, and the second focal point of the elliptical surface of the elliptical mirror is located in the illumination target area (Ai). When such an ellipsoidal mirror is used as the first focusing means, the focusing lens (4a) becomes unnecessary.
[0192] さらに、 R、 G、 Bの三色の独立な LEDを用いるカラーの画像読取装置用の照明装 置を説明する。例えば、図 17 (b)及び (c)に示すように、図 17に示されるような L；!〜 L7の LEDを、一色の LEDで構成すると共に、他の二色の LEDを追加する。具体的 には、図 17 (c)に示すように、一色（G)の LEDの副走査方向（Sy)の両側に、他の 二色（R及び B)の LEDを配置することによって、三色の LEDで構成される光源を提 供すること力 Sできる。図 17 (c)に示すような照明装置の例は、図 16に示すような照明 装置の例と同様に機能する。 （ただし、図 16 (b)における集光レンズ (2c)の位置に 集束レンズ (4a)を配置し、 a、 b、 cの関係のうち c = 0とする）。 実施例 8 [0192] Furthermore, an illumination device for a color image reading device using independent LEDs of three colors R, G, and B will be described. For example, as shown in FIGS. 17 (b) and 17 (c), the LEDs L ;! to L7 as shown in FIG. 17 are formed of one color LED and the other two color LEDs are added. Specifically, as shown in Fig. 17 (c), the other two colors (R and B) LEDs are arranged on both sides of the one color (G) LED in the sub-scanning direction (Sy). It is possible to provide a light source composed of colored LEDs. The example of the illumination device as shown in FIG. 17 (c) functions in the same manner as the example of the illumination device as shown in FIG. (However, the focusing lens (4a) is placed at the position of the focusing lens (2c) in Fig. 16 (b), and c = 0 in the relationship between a, b, and c). Example 8
[0193] 図 19は、本発明の第八の実施例による照明装置の例を説明する図である。図 19 ( a)は、本発明の第八の実施例による照明装置の別の例の上面図であり、図 19 (b)は 、本発明の第八の実施例による画像読取装置の別の例の正面図である。  FIG. 19 is a diagram for explaining an example of a lighting apparatus according to the eighth embodiment of the present invention. FIG. 19 (a) is a top view of another example of an illuminating device according to the eighth embodiment of the present invention, and FIG. 19 (b) shows another image reading device according to the eighth embodiment of the present invention. It is a front view of an example.
[0194] 本発明の第一〜第七の実施例においては、照明レンズとして、隣接して配置され た複数の凸シリンダレンズで構成されるシリンダレンズアレイを示してきたが、照明レ ンズとして、隣接して配置された複数の凹シリンダレンズで構成されるシリンダレンズ アレイを用いることもできる。  [0194] In the first to seventh embodiments of the present invention, a cylinder lens array composed of a plurality of adjacent convex cylinder lenses has been shown as the illumination lens. A cylinder lens array composed of a plurality of concave cylinder lenses arranged adjacent to each other can also be used.
[0195] 図 19に示すような照明装置の例においては、照明レンズ (3)として、隣接して配置 された複数の凹シリンダレンズで構成されるシリンダレンズアレイが使用されている。 照明レンズ (3)として、隣接して配置された複数の凹シリンダレンズで構成されるシリ ンダレンズアレイを用いた場合であっても、 LED (1)から発生する光束を、主走査方 向（Sx)において、拡散させること力 Sできる。ここで、シリンダレンズアレイを構成する 各々の凹シリンダレンズの焦点距離力 であり、且つ、 LED (1)の一つに対応する凹 シリンダレンズの主点から照明対象面 (撮像領域） (Ai)までの距離力 ¾であるとすると 、主走査方向（Sx)における LED (1)の一つから放出された光の光束の幅の拡大率 Qは、  In the example of the illumination device as shown in FIG. 19, a cylinder lens array composed of a plurality of adjacent concave cylinder lenses is used as the illumination lens (3). Even when a cylinder lens array composed of a plurality of contiguous concave cylinder lenses is used as the illumination lens (3), the luminous flux generated from the LED (1) is transmitted in the main scanning direction ( In Sx), it is possible to diffuse S. Here, the focal length force of each concave cylinder lens that constitutes the cylinder lens array, and the illumination target surface (imaging area) (Ai) from the principal point of the concave cylinder lens corresponding to one of the LEDs (1) If the distance force up to ¾, the expansion factor Q of the width of the luminous flux of light emitted from one of the LEDs (1) in the main scanning direction (Sx) is
[0196] [数 13] f  [0196] [Equation 13] f
[0197] であり、本発明の実施形態において、 Qは、 2以上である。 [0197] In the embodiment of the present invention, Q is 2 or more.
実施例 9  Example 9
[0198] 本発明の第一〜第八の実施例においては、画像読取装置における原稿台（コンタ タトガラス）並びに結像レンズ及び一次元撮像装置を含む読取系が、固定される一方 で、第一走行体及び第二の走行体が、副走査方向において、差動的に移動する。 そして、第一走行体に、本発明の第一〜第八の実施例による照明装置が、搭載され る。第一走行体には、照明装置を除けば、撮像領域から反射された光の光路を折り 曲げる変向ミラーのみを搭載するので、第一走行体の質量は、増加せずに、第一走 行体及び第二の走行体の移動による画像の読取は、高速の読取に適する。しかしな がら、低速な読取が許容される場合には、読取装置も第一走行体上に搭載すること も考えられる。なお、この場合には、第二走行体は、不必要となるので、走行体は一 つのみでもよい。）。 [0198] In the first to eighth embodiments of the present invention, the reading system including the document table (container glass), the imaging lens, and the one-dimensional imaging device in the image reading device is fixed, while the first The traveling body and the second traveling body move differentially in the sub-scanning direction. And the illuminating device by the 1st-8th Example of this invention is mounted in a 1st traveling body. Except for the lighting device, the first traveling body is equipped only with a turning mirror that bends the optical path of the light reflected from the imaging region, so that the mass of the first traveling body does not increase and the first traveling body does not increase. Reading an image by moving the row body and the second traveling body is suitable for high-speed reading. However, if low-speed reading is permitted, it is conceivable that a reading device is also mounted on the first traveling body. In this case, since the second traveling body is unnecessary, only one traveling body may be provided. ).
[0199] 図 20は、本発明の第九の実施例による画像読取装置の例を説明する図である。図 20 (a)は、本発明の第九の実施例による画像読取装置の一つの例を説明する図で あり、図 20 (b)は、本発明の第九の実施例による画像読取装置の別の例を説明する 図である。  FIG. 20 is a view for explaining an example of an image reading apparatus according to the ninth embodiment of the present invention. FIG. 20 (a) is a diagram for explaining an example of an image reading apparatus according to the ninth embodiment of the present invention, and FIG. 20 (b) is an illustration of the image reading apparatus according to the ninth embodiment of the present invention. It is a figure explaining another example.
[0200] 図 20 (a)及び (b)に示すような画像読取装置においては、本発明の第一〜第八の 実施例による照明装置としての照明ユニット（10)が、読取系としての読取ユニット（1 6)と共に走行体（11a)に搭載される。読取ユニット（16)は、結像レンズ及び撮像素 子を含む縮小光学系であるため、原稿面から結像レンズまでのある程度の距離が、 要求される。  In the image reading apparatus as shown in FIGS. 20 (a) and 20 (b), the illumination unit (10) as the illuminating device according to the first to eighth embodiments of the present invention reads as a reading system. It is mounted on the traveling body (11a) together with the unit (16). Since the reading unit (16) is a reduction optical system including an imaging lens and an imaging element, a certain distance from the document surface to the imaging lens is required.
[0201] 図 20 (a)に示すような画像読取装置においては、原稿面からの反射された画像光 は、一旦変向ミラー（12)によって、コンタクトガラス（13)に平行な方向に変向させら れた後、二つの折返しミラー（17a)及び（17b)で、各々 2回ずつ、折り返された後に 、読取ユニット（16)へ導かれる。  [0201] In the image reading apparatus as shown in Fig. 20 (a), the image light reflected from the document surface is once redirected by the deflecting mirror (12) in the direction parallel to the contact glass (13). After being folded, the two folding mirrors (17a) and (17b) are each folded twice and guided to the reading unit (16).
[0202] 図 20 (b)に示すような画像読取装置においては、原稿面からの反射された画像光 は、変向ミラー（12)によって斜め右上に向かって折り返され、第一の折返しミラー（1 7a)によって、コンタクトガラス（13)に平行な方向に変向させられた後、第二の折り返 しミラー（17b)に向けらける。その第二の折返しミラー（17b)に入射した光は、少し下 向きに再度反射させて、再度、第一の折返しミラー（17a)に戻される。第一の折返し ミラー（17a)に戻された光は、斜め下側に反射させられ、第三の折返しミラー（17c) でさらに反射させられ、コンタクトガラス（13)の面に平行な方向において、 読取ユニット (11)へ導かれる。  [0202] In the image reading apparatus as shown in Fig. 20 (b), the image light reflected from the document surface is folded back diagonally to the upper right by the turning mirror (12), and the first folding mirror ( After being changed in a direction parallel to the contact glass (13) by 17a), it is directed to the second folding mirror (17b). The light incident on the second folding mirror (17b) is reflected again slightly downward and returned again to the first folding mirror (17a). The light returned to the first folding mirror (17a) is reflected obliquely downward, further reflected by the third folding mirror (17c), and in a direction parallel to the surface of the contact glass (13), Guided to reading unit (11).
[0203] 図 20 (a)及び (b)に示すように、読取ユニット（11)のような読取系及び照明ユニット  [0203] As shown in FIGS. 20 (a) and (b), a reading system such as a reading unit (11) and an illumination unit.
(10)のような照明系の両方を走行体（11a)上に搭載する場合であっても、発明の第 一〜第八の実施例による照明装置のいずれも、照明ユニット（10)として用いることが できる。図 20 (a)においては、図 7 (e)に示す照明装置を直接採用している。図 20 (b )に示すような画像読取装置においては、図 20 (a)に示す画像読取装置における第 一の集束手段としての回転放物面鏡の代わりに、凸レンズを用いたものである。 実施例 10 Even when both of the illumination systems such as (10) are mounted on the traveling body (11a), any of the illumination devices according to the first to eighth embodiments of the invention is used as the illumination unit (10). Can it can. In Fig. 20 (a), the lighting device shown in Fig. 7 (e) is directly adopted. In the image reading apparatus as shown in FIG. 20 (b), a convex lens is used instead of the rotary parabolic mirror as the first focusing means in the image reading apparatus shown in FIG. 20 (a). Example 10
[0204] 本発明の第一〜第九の実施例においては、撮像素子で画像を読み取る縮小光学 系又はディジタル画像読取装置に搭載するための照明装置及び照明方法を説明し てきた。しかしながら、本発明の第一〜第九の実施例に示すような照明装置及び照 明方法を、等倍光学系又はアナログ複写機に搭載するための照明方法としても使用 可能である。  In the first to ninth embodiments of the present invention, the illuminating device and the illuminating method for mounting on a reduction optical system or a digital image reading device that reads an image with an image sensor has been described. However, the illumination apparatus and illumination method as shown in the first to ninth embodiments of the present invention can also be used as an illumination method for mounting in an equal magnification optical system or an analog copying machine.
[0205] 図 21は、本発明の第十の実施例による画像読取装置の例を説明する図である。図  FIG. 21 is a diagram for explaining an example of an image reading apparatus according to the tenth embodiment of the present invention. Figure
21に示すような画像読取装置の例は、シート状の原稿を複写する画像形成装置用 の画像読取装置である。結像レンズ（14)は、マイクロレンズアレイであり、多数のマク 口レンズを、マイクロレンズアレイの長さ力 紙のようなシート原稿（33)の幅と同じ長さ となるように、配列させたものである。結像レンズ（14)は、等倍光学系を提供するた めに、撮像領域 (Ai)と感光体（31)のちようど中間に配置される。シート原稿（33)と の摩擦が少ないコンタクトガラス（13)上の撮像領域 (Ai)部分で、紙送りローラ（32) によって、シート原稿（33)は、圧接されると共に送られる。シート原稿の送りと同期し て（同じ速度で)感光体（31)を移動させる。なお、感光体（31)を帯電させる帯電装 置及び転写装置のような感光体の周辺装置の図示は、省略した。  An example of the image reading apparatus as shown in FIG. 21 is an image reading apparatus for an image forming apparatus that copies a sheet-like document. The imaging lens (14) is a microlens array, and a number of aperture lenses are arranged so as to have the same length as the width of a sheet document (33) such as a length lens of the microlens array. It is a thing. The imaging lens (14) is arranged between the imaging area (Ai) and the photoconductor (31) in order to provide an equal-magnification optical system. The sheet document (33) is pressed and fed by the paper feed roller (32) in the imaging region (Ai) portion on the contact glass (13) with little friction with the sheet document (33). The photoconductor (31) is moved in synchronization with the feeding of the sheet document (at the same speed). Note that illustration of peripheral devices of the photosensitive member such as a charging device and a transfer device for charging the photosensitive member (31) is omitted.
[0206] 図 21に示すような画像読取装置の例において、照明装置は、図 7 (b)に示す照明 装置において、走行体を除去し、折り返しミラーの位置を変えたものである。このよう な照明装置を使用して、シート原稿（33)の撮像領域 (Ai)を一次元に照明し、シート 原稿（33)上の画像を、結像レンズ（14)を介して感光体（31)上に投影している。そ して、シート原稿（33)及び感光体（31)を順次移動させることによって、シート原稿（3 3)上の画像の全体を、感光体（31)上に二次元画像として投影することができる。そ の後、アナログ複写機のプロセスとして、一般に使われている紙と同じ、普通紙上に 画像を転写して、画像のハードコピーを得るが、公知のアナログ複写プロセスの詳細 な説明は省略する。 [0207] このように、アナログ複写機においても、本発明の実施形態による照明方法及び照 明装置を使用して、照度むらを軽減することができるので、高品質な画像を得ること ができる。 In the example of the image reading apparatus as shown in FIG. 21, the illuminating apparatus is obtained by removing the traveling body and changing the position of the folding mirror in the illuminating apparatus shown in FIG. 7 (b). Using such an illuminating device, the imaging area (Ai) of the sheet original (33) is illuminated one-dimensionally, and the image on the sheet original (33) is transferred to the photoconductor (14) via the imaging lens (14). 31) Projecting above. Then, by sequentially moving the sheet original (33) and the photosensitive member (31), the entire image on the sheet original (33) can be projected as a two-dimensional image on the photosensitive member (31). it can. After that, as an analog copying machine process, an image is transferred onto plain paper, which is the same as a commonly used paper, to obtain a hard copy of the image, but detailed description of the known analog copying process is omitted. [0207] As described above, even in an analog copying machine, unevenness in illuminance can be reduced by using the illumination method and the illumination device according to the embodiment of the present invention, so that a high-quality image can be obtained.
[0208] 以上の説明は照明対象面 (撮像領域)を均一に照明する方法を述べてきた。等倍 光学系を用いた画像読取装置、或いは画像形成装置用に適用するにはそのままの 適用がよい。縮小光学系を用いた画像読取装置では結像レンズのコサイン 4乗特性 (cos4 Θ特性）により、主走査方向の照明対象領域の中央部はその周辺部より光量 を落としたほうが総合的に省エネとなり都合が良い。その場合、コサイン 4乗特性に合 わせて、光源である LEDの間隔を周辺部から中央部に向かって粗くしていくことによ つて容易に実現できる。勿論、その場合、一番粗い場所においても LEDが発光する 光束を LEDの間隔の 2倍以上に拡散をさせるのが望ましい。 [0208] The above description has described a method of uniformly illuminating the illumination target surface (imaging region). For application to an image reading apparatus using an equal magnification optical system or an image forming apparatus, the application as it is is good. In an image reader that uses a reduction optical system, it is possible to save energy by reducing the amount of light at the center of the illumination target area in the main scanning direction from the periphery due to the cosine fourth power (cos 4 Θ) characteristic of the imaging lens. It becomes convenient. In that case, it can be easily realized by increasing the distance between the LEDs, which are the light sources, from the peripheral part toward the central part in accordance with the cosine fourth power characteristic. Of course, in that case, it is desirable to diffuse the luminous flux emitted from the LED even in the roughest place more than twice the LED interval.
[0209] 図 22は、縮小光学系を用いた画像読取装置における撮像領域 (Ai)での照度分布  FIG. 22 shows the illuminance distribution in the imaging area (Ai) in the image reading apparatus using the reduction optical system.
(Di)及び CCD上での縮小光学系の相対明度の関係を説明する図である。図 22 (a) は、縮小光学系を用いた画像読取装置における撮像領域 (Ai)、結像レンズ、及び 一次元 CCDの配置を示す図であり、図 22 (b)は、（1)結像レンズによって一次元 CC D上に結像される画像の明度分布と、（2)撮像領域 (Ai)に要求される照度分布（Di) の関係を説明する図である。  It is a figure explaining the relationship between (Di) and the relative brightness of the reduction optical system on CCD. Fig. 22 (a) is a diagram showing the arrangement of the imaging area (Ai), imaging lens, and one-dimensional CCD in an image reader using a reduction optical system. Fig. 22 (b) shows (1) results. It is a figure explaining the relationship between the brightness distribution of the image imaged on one-dimensional CCD by an image lens, and the illuminance distribution (Di) requested | required of (2) imaging region (Ai).
[0210] 図 22 (a)に示すように、撮像領域 (Ai)に平行に一次元 CCDを置き、その間に結像 レンズ（14)を置いて、その一次元 CCD上に画像を結像させる画像読取装置におい て、撮像領域 (Ai)における画像を、結像レンズ（14)によって、一次元撮像素子（15 )としての一次元 CCDに結像させた場合には、その結像レンズ（14)によって結像さ れる一次元 CCD上の中央部における画像の明度に対して、その一次元 CCD上の 周辺部における画像の明度は低くなる。  [0210] As shown in Fig. 22 (a), a one-dimensional CCD is placed parallel to the imaging area (Ai), and an imaging lens (14) is placed between them to form an image on the one-dimensional CCD. In the image reading apparatus, when an image in the imaging region (Ai) is imaged on a one-dimensional CCD as a one-dimensional imaging device (15) by the imaging lens (14), the imaging lens (14 ), The brightness of the image on the periphery of the one-dimensional CCD is lower than the brightness of the image on the center of the one-dimensional CCD.
[0211] 図 22 (a)において、 Wを、主走査方向（Sx)における撮像領域 (Ai)の長さとし、結 像レンズ（14)を、撮像領域 (Ai)の中心の鉛直方向にその光軸を有するように配置し 、 Ldを、撮像領域 (Ai)から結像レンズ（14)までの距離とすると、結像レンズ（14)の 光軸に対して結像レンズ（14)に入射する光線の角度 Θの最大値 Θ は、  [0211] In Fig. 22 (a), W is the length of the imaging region (Ai) in the main scanning direction (Sx), and the imaging lens (14) is moved in the vertical direction at the center of the imaging region (Ai). If the Ld is the distance from the imaging region (Ai) to the imaging lens (14), it is incident on the imaging lens (14) with respect to the optical axis of the imaging lens (14). The maximum angle Θ of the ray angle Θ is
max  max
Θ =tan_ 1 [W/ (2 X Ld) ] となる。 Θ = tan _ 1 [W / (2 X Ld)] It becomes.
[0212] このとき、一次元 CCD上の主走査方向（Sx)における各位置での結像レンズ（14) によって結像される画像の明度の相対値は、いわゆるコサイン 4乗則に従って、その 位置に対応する撮像領域 (Ai)における位置から結像レンズに入射する光線の角度 Θに対して、図 22 (b)の曲線（1)に示すような cos4 Θで変化する。その結果、主走査 方向（Sx)の中心における結像レンズ（14)によって結像される一次元 CCD上の画 像の明度に対して、主走査方向（Sx)の周辺における結像レンズ（14)によって結像 される一次元 CCD上の画像の明度は、数 10%低くなる。 [0212] At this time, the relative value of the brightness of the image formed by the imaging lens (14) at each position in the main scanning direction (Sx) on the one-dimensional CCD is determined according to the so-called cosine fourth law. It changes with cos 4 Θ as shown in curve (1) of Fig. 22 (b) with respect to the angle Θ of the light ray incident on the imaging lens from the position in the imaging region (Ai) corresponding to. As a result, for the brightness of the image on the one-dimensional CCD imaged by the imaging lens (14) in the center of the main scanning direction (Sx), the imaging lens (14 The brightness of the image on the one-dimensional CCD imaged by) is reduced by several tens of percent.
[0213] 一方、一次元 CCDに入射する光量は、一次元 CCDによって電気信号に変換され るので、その光量を電気信号に変換した後に、その電気信号の増幅率を変化させる ことによって、結像レンズ（14)によって結像される画像の明度の差異を補正すること は、可能である。し力もながら、この場合には、ダイナミックレンジが小さくなつてしまう ので、結像レンズ（14)によって結像される画像の明度が相対的に低い一次元 CCD の周辺では、ノイズが増加する。その結果、一次元 CCDで読み取られた画像が汚く なる。  [0213] On the other hand, the amount of light incident on the one-dimensional CCD is converted into an electric signal by the one-dimensional CCD. Therefore, after converting the amount of light into an electric signal, the amplification factor of the electric signal is changed to form an image. It is possible to correct the difference in brightness of the image formed by the lens (14). However, in this case, since the dynamic range is reduced, noise increases around the one-dimensional CCD where the brightness of the image formed by the imaging lens (14) is relatively low. As a result, the image read by the one-dimensional CCD becomes dirty.
[0214] そこで、図 22 (b)の曲線（1)に示す関係と逆比例するように、結像レンズ（14)の撮 像領域 (Ai)側に、結像レンズ（14)の光軸付近の撮像領域 (Ai)の位置からの光に ついての遮光量が多くなるような遮光マスクを揷入する力、、又は、光源からの光を反 射させる反射板の反射率を、反射板の中央における反射率が低くなるように変化さ せることによって、一次元 CCDに結像される光の照度を一定にすることも考えられる 。このような場合には、電気信号の補正を低減することが可能になる。しかしながら、 光源から放出される光を遮光する又は捨てることは、省エネルギーの観点からは、望 ましくない。  [0214] Therefore, the optical axis of the imaging lens (14) is placed on the imaging region (Ai) side of the imaging lens (14) so as to be inversely proportional to the relationship shown by the curve (1) in Fig. 22 (b). The power to insert a light shielding mask that increases the amount of light shielded from the position of the nearby imaging area (Ai), or the reflectance of the reflector that reflects light from the light source It is also possible to make the illuminance of the light imaged on the one-dimensional CCD constant by changing the reflectivity at the center of the LED to be low. In such a case, the correction of the electric signal can be reduced. However, it is not desirable from the viewpoint of energy saving to block or discard the light emitted from the light source.
[0215] 即ち、光源力も発生する光束を捨てることなぐ図 22 (b)の曲線（2)に示す撮像領 域 (Ai)に要求される照度分布（Di)になるように、撮像領域 (Ai)を照明するのが望ま しい。そうすれば、光源から放出される光の利用効率を向上させることができ、その結 果、撮像領域 (Ai)を照明する光のエネルギーを低減する（省エネルギーを達成する )こと力 Sでさる。 [0216] 結像レンズ（14)によって結像される一次元撮像素子（CCD) (15)上の画像の明 度分布を一定にする方法としては、例えば、 LEDのような複数の光源の間隔を変え て対応する方法、撮像領域 (Ai)力 複数の光源までの距離を変えて対応する方法、 複数の光源から放出される光の光束の発散角を変えて対応する方法、及び、照射対 象面に対する複数の光源の光軸の方向を変えて対応する方法が、挙げられる。この ような方法を採用することによって、主走査方向（Sx)における撮像領域 (Ai)を照明 する光の照度分布（Di)力 図 22 (b)の曲線（2)に示すような l/cos4 eの特性を有 するように、複数の光源の配置を変えて対応すればよい。 [0215] That is, the imaging region (Ai) is obtained so that the illuminance distribution (Di) required for the imaging region (Ai) shown in the curve (2) in Fig. 22 (b) without throwing away the luminous flux that also generates the light source power. ) Should be illuminated. Then, the utilization efficiency of the light emitted from the light source can be improved, and as a result, the energy S for reducing the energy of the light illuminating the imaging area (Ai) (achieving energy saving) can be reduced. [0216] As a method for making the brightness distribution of the image on the one-dimensional imaging device (CCD) (15) imaged by the imaging lens (14) constant, for example, the interval between a plurality of light sources such as LEDs is used. , Changing the distance to a plurality of light sources, changing the divergence angle of the light flux emitted from the plurality of light sources, A method of changing the direction of the optical axes of a plurality of light sources with respect to the elephant surface is available. By adopting such a method, the illuminance distribution (Di) power of the light illuminating the imaging area (Ai) in the main scanning direction (Sx) l / cos as shown in the curve (2) in Fig. 22 (b) It is sufficient to change the arrangement of multiple light sources so as to have the characteristics of 4e.
実施例 11  Example 11
[0217] 本発明の第 11の実施例は、複数の光源の配置間隔を変えて撮像対象領域 (撮像 領域）（Ai)を照明する光の照度分布（Di)を l/cos4 6の特性に一致させる例を示 す。 Eleventh embodiment of the [0217] present invention, the illuminance distribution of the light illuminating the imaging target region (imaging region) (Ai) by changing the arrangement interval of the plurality of light sources (Di) of l / cos 4 6 Characteristics An example of matching is shown below.
[0218] 図 23は、一次元 CCDに結像される画像の相対明度が一定となるような、撮像対象 領域 (Ai)を照明する複数の光源の配置間隔を決定する方法を説明する図である。  FIG. 23 is a diagram for explaining a method for determining the arrangement intervals of a plurality of light sources that illuminate the imaging target area (Ai) so that the relative brightness of the image formed on the one-dimensional CCD is constant. is there.
[0219] 一次元 CCDに結像される画像の相対明度が一定となるようにするためには、撮像 対象領域 (Ai)を照明する複数の光源 (例えば、 LED)の配置間隔を中央部 (結像レ ンズの光軸）から離れるに従って狭めていく。図 23においては、図 22 (a)に示す配置 を、 90度反時計まわりに回転させて示しており、そこに示した記号で、図 22における 記号と同じ記号は同じ意味である。なお、図 23において、 Whは、主走査方向（Sx) における撮像対象領域 (Ai)の長さ Wの半分であり、撮像対象領域 (Ai)の中心から 計算される。  [0219] In order to make the relative brightness of the image formed on the one-dimensional CCD constant, the arrangement interval of a plurality of light sources (for example, LEDs) that illuminate the imaging target area (Ai) is set at the center ( It narrows away from the imaging lens. In FIG. 23, the arrangement shown in FIG. 22 (a) is shown rotated by 90 degrees counterclockwise. In the symbols shown there, the same symbols as those in FIG. 22 have the same meaning. In FIG. 23, Wh is half the length W of the imaging target area (Ai) in the main scanning direction (Sx), and is calculated from the center of the imaging target area (Ai).
[0220] 一次元 CCDに結像される画像の相対明度が一定となるような、撮像対象領域 (Ai) を照明する複数の光源の間隔を計算するために、副走査方向（Sy)については光源 力、らの光束が発散しないことを前提として、設計する又はシミュレーションすることに する。具体的には、副走査方向（Sy)においては、複数の光源から放出される光を平 行光として撮像対象領域 (Ai)を照明するか、複数の光源から放出される光を撮像対 象領域 (Ai)に集束させる力、、又はそれらの中間のいずれかを採用する。  [0220] In order to calculate the interval between multiple light sources that illuminate the imaging target area (Ai) so that the relative brightness of the image formed on the one-dimensional CCD is constant, the sub-scanning direction (Sy) The design or simulation is based on the premise that the light source power and other luminous fluxes do not diverge. Specifically, in the sub-scanning direction (Sy), the imaging target area (Ai) is illuminated using light emitted from a plurality of light sources as parallel light, or light emitted from a plurality of light sources is to be imaged. Adopt either the force focused on the area (Ai), or somewhere in between.
[0221] 図 23に示すように、図 23の中心線（結像レンズの光軸）に対して上半分の領域及 び下半分の領域は、対称であるので、説明の都合上、下半分の領域のみを用いて 説明する。まず、その下半分の領域 (主走査方向（Sx)における撮像対象領域 (Ai) の半分）を N分割し、中心線上の点を原点とする。さらに、その原点の点番号を 0とす ると共に、各分割点の点番号を、原点に近い順に l〜nと番号付けて、原点 0から分 割点 1までの間隔、分割点 1から分割点 2までの間隔、 · · ·、分割点 n— 1から終点 nま での間隔を、それぞれ、 wl、 w2、 · · ·、 wnによって表す。 [0221] As shown in FIG. 23, the upper half region and the center line of FIG. 23 (the optical axis of the imaging lens) Since the lower half region is symmetrical, only the lower half region will be described for convenience of explanation. First, the lower half area (half of the imaging target area (Ai) in the main scanning direction (Sx)) is divided into N, and the point on the center line is set as the origin. Furthermore, the point number of the origin is set to 0, and the point numbers of each division point are numbered l to n in the order from the origin, and the interval from origin 0 to division point 1 is divided from division point 1. The interval from point 2 to ..., and the interval from division point n—1 to end point n are represented by wl, w2,.
[0222] ここで、図 22 (b)の曲線（2)に示す撮像対象領域 (Ai)に要求される照度分布（Di) になるような wl〜wnの間隔を得るのだが、下半分の領域（主走査方向（Sx)におけ る撮像対象領域 (Ai)の半分）の N分割を、最初は N等分にする。そして、撮像対象 領域 (Ai)全域が一定照度で照明されている場合として、結像レンズによって一次元 CCD上に結像される各分割点に対応する位置の相対明度を、コサイン四乗則によ つて求める。具体的には、撮像対象領域 (Ai)上の k番目の分割点に対応する結像レ ンズによって一次元 CCD上に結像する画像の相対明度は、 cos4 Θ である。また、こ [0222] Here, the interval between wl and wn is obtained so that the illuminance distribution (Di) required for the imaging target area (Ai) shown in the curve (2) in Fig. 22 (b) is obtained. The N division of the area (half of the imaging target area (Ai) in the main scanning direction (Sx)) is initially divided into N equal parts. Then, assuming that the entire area to be imaged (Ai) is illuminated with a constant illuminance, the relative brightness of the position corresponding to each division point imaged on the one-dimensional CCD by the imaging lens is expressed by the cosine fourth law. So ask. Specifically, the relative brightness of the image formed on the one-dimensional CCD by the imaging lens corresponding to the kth division point on the imaging target area (Ai) is cos 4 Θ. Also this
k  k
れらの相対明度の総和は、  The sum of their relative brightness is
[0223] [数 14] [0223] [Equation 14]
[0224] である。ここで、 Θ は、結像レンズの光軸に対する、結像レンズの中心と撮像対象領 [0224]. Where Θ is the center of the imaging lens and the area to be imaged with respect to the optical axis of the imaging lens.
k  k
域 (Ai)の k番目の分割点とを結ぶ直線の角度である。なお、 Θ は、結像レンズの光 軸に対する、結像レンズの中心と n番目の分割点とを結ぶ直線の角度であり、 Θ max と一致する。  This is the angle of the straight line connecting the kth division point of the area (Ai). Note that Θ is the angle of a straight line connecting the center of the imaging lens and the nth division point with respect to the optical axis of the imaging lens and coincides with Θ max.
[0225] 次に、各分割点に対応した相対明度に比例した分割で各分割点間の距離を与え 直す。即ち N分割点間の間隔 wl , w2, · · · , wnを、式  [0225] Next, the distance between the division points is given again by division in proportion to the relative brightness corresponding to each division point. That is, the intervals wl, w2, ...
[0226] [数 15] ! cos4 θι [0226] [Equation 15] ! cos 4 θ ι
wl = x Wh  wl = x Wh
Sb  Sb
cos4 Θ- w2 xWh cos 4 Θ- w2 xWh
Sb  Sb
Sb Sb
[0227] に従って、算出する。 Calculate according to [0227].
[0228] ここで得られた各分割点間の間隔 wl, w2, ···, wnは、 目標とする間隔から少しず れているので、再度、同様の計算をする。  [0228] The intervals wl, w2, ···, wn obtained here are slightly deviated from the target intervals, so the same calculation is performed again.
[0229] まず、各分割点の位置を上式で得られた間隔 wl , w2, · · · , wnで分割し直し、結像 レンズの光軸に対する、結像レンズの中心と k番目の分割点とを結ぶ直線の角度 Θ ' を算出する。次に、得られた間隔 wl, w2, ···, wnの各々で各分割点に対応する一 k [0229] First, the position of each dividing point is divided again by the intervals wl, w2, ···, wn obtained by the above formula, and the center of the imaging lens and the kth division with respect to the optical axis of the imaging lens Calculate the angle Θ 'of the straight line connecting the points. Next, one k corresponding to each dividing point in each of the obtained intervals wl, w2,..., Wn
次元 CCD上に結像する画像の相対明度を、コサイン四乗則によって求める。具体的 には、 k番目の分割点に対応する一次元 CCD上に結像する画像の相対明度は、 co s40 ' である。また、その相対明度の総和は、 The relative brightness of the image formed on the two-dimensional CCD is obtained by the cosine fourth law. Specifically, the relative brightness of the image formed on the one-dimensional CCD corresponding to the kth division point is co s 4 0 ′. The sum of the relative brightness is
k  k
[0230] [数 16]  [0230] [Equation 16]
S = >:cos4 θ S =>: cos 4 θ
[0231] である。 [0231].
[0232] ここで、これを基に、改めてそれぞれの分割点間の間隔 w' 1, w'2, ···, w'nを、式 [0233] [数 17] cos4 θ [0232] Here, based on this, the distances w ′ 1, w′2,..., W′n between the respective dividing points are newly expressed as [0233] [Equation 17] cos 4 θ
wl = L χ Wn wl = L χ Wn
Sb'  Sb '
cos4 θ „„ cos 4 θ „„
Sb'  Sb '
Sb' Sb '
[0234] に従って、算出する。 [0235] このような演算を無限回繰り返すことによって、 目標とする分割点間の間隔に限りな く近づくのであるが、後述するように、 Nを 12としてミュレーシヨンした結果では、最初 の演算によって得られた間隔 wl, w2, ···, wnと、二回目の演算によって得られた間 隔 w'l, w'2, ···, w'nのそれぞれ対応する間隔の差異は、最大で ±0· 4%未満で あった。このような差異は、実用上、（部品の精度や加工精度などのような）他の要因 の変動より遥かに小さいので、最初の演算によって得られた間隔 wl, w2, ···, wnを 用いても問題はない。 Calculate according to [0234]. [0235] By repeating such an operation infinitely, the target interval between the dividing points is approached as much as possible. As will be described later, the result of muting with N equal to 12 is obtained by the first operation. The difference between the corresponding intervals wl, w2, ..., wn and the intervals w'l, w'2, ..., w'n obtained by the second calculation is the largest. It was less than ± 0 · 4%. Such differences are practically much smaller than other factors (such as part accuracy and machining accuracy), so the distances wl, w2,. There is no problem even if it is used.
[0236] このように求めた撮像対象領域 (Ai)の分割点に対応して L0の距離上に光源を配 置して、撮像対象領域 (Ai)の周辺部まで l/cos4eの照度分布を与えようとすると、 撮像対象領域 (Ai)幅 Wを超えて光源を配置する必要がある。即ち、 0から nまでの位 置の N個の光源以外に、撮像対象領域 (Ai)から L0離れた線上の撮像対象領域 (Ai )から外れた延長線上にも n+l、 n+2、 n+3、 ···と光源を配置する必要がある（こ の配置位置は上述の計算方法を演繹すれば容易に求まるが、詳しい説明は省略す る）。 [0236] Illuminance of l / cos 4 e up to the periphery of the imaging target area (Ai) by arranging the light source on the distance of L0 corresponding to the division point of the imaging target area (Ai) thus obtained In order to give the distribution, it is necessary to place the light source beyond the imaging target area (Ai) width W. In other words, in addition to the N light sources at positions 0 to n, n + l, n + 2, and n + l, n + 2, and an extension line deviating from the imaging target area (Ai) on the line L0 away from the imaging target area (Ai) It is necessary to arrange n + 3, ... and the light source (this arrangement position can be easily obtained by deducing the above calculation method, but detailed explanation is omitted).
[0237] 次に、間隔が調整された複数の光源によって照明される撮像対象領域 (Ai)の照度 分布を求める方法を示す。  [0237] Next, a method for obtaining the illuminance distribution of the imaging target area (Ai) illuminated by a plurality of light sources with adjusted intervals will be described.
[0238] 図 24は、一次元 CCDに結像される画像の相対明度が一定となるような、撮像対象 領域 (Ai)を照明する複数の光源の具体的な配置を説明する図である。図 24(a)は、 複数の光源の配置及び側面鏡を配置する鏡面の位置を示す図であり、図 24(b)は、 光源の放射特性の例を示す図である。 FIG. 24 is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate the imaging target area (Ai) so that the relative brightness of an image formed on the one-dimensional CCD is constant. FIG. 24 (a) is a diagram showing the arrangement of a plurality of light sources and the position of the mirror surface where the side mirrors are arranged, and FIG. 24 (b) is a diagram showing an example of the radiation characteristics of the light sources.
図 24(a)は、図 23の撮像対象面 (撮像対象領域）（Ai)より左側に表現した部分の 拡大図である。  FIG. 24 (a) is an enlarged view of a portion expressed on the left side of the imaging target surface (imaging target area) (Ai) in FIG.
[0239] 図 24(a)に示すように、照明対象領域 (撮像対象領域）（Ai)から L0だけ離れ、且 つ撮像対象領域 (Ai)に対して平行に、上述の説明で得られた間隔で N分割すること によって、得られた各分割点に光源を置いている。更に、その外側 PM1の位置に鏡 面 (側面鏡)を置いて、撮像対象領域 (Ai)の各位置の相対照度を算出する。この鏡 面は、撮像対象領域 (Ai)の範囲を分割した点に対応した光源配置位置上に置いた 複数の光源から放出される光束を反射させて、あた力、もその延長線上に光源がある かのように照明対象領域 (Ai)の範囲を照射させている。 [0239] As shown in Fig. 24 (a), the distance from the illumination target area (imaging target area) (Ai) by L0 and parallel to the imaging target area (Ai) was obtained in the above description. By dividing N at intervals, a light source is placed at each obtained division point. Further, a mirror surface (side mirror) is placed at the position of the outside PM1, and the relative illuminance at each position of the imaging target area (Ai) is calculated. This mirror surface reflects the luminous flux emitted from a plurality of light sources placed on the light source arrangement position corresponding to the point where the range of the imaging target area (Ai) is divided, and the light force is also on the extension line of the light source. Is The area of the illumination target area (Ai) is illuminated as if.
[0240] 図 24 (a)においては、主走査方向（Sx)における撮像対象領域 (Ai)の半分を N分 割することによって得られた n + 1個の光源の位置を、 P , P , · ' ·Ρとすると共に、 η番 [0240] In Fig. 24 (a), the positions of n + 1 light sources obtained by dividing half of the imaging target area (Ai) in the main scanning direction (Sx) by N are denoted by P 1, P 2, · '· Ρ and η
0 1 η  0 1 η
目の光源の外側 PM1の位置に設けられる側面鏡によって得られる、 Ρ , Ρ , · ' ·Ρに  側面,,, · '· Ρ obtained by a side mirror provided at the position of PM1 outside the light source of the eye
0 1 η 配置された光源の像 (虚光源 VLS)の位置を Ρ , Ρ , · ' ·Ρ とする。ここで、 Ρ n+ 1 n + 2 2n+ l n の位置に置かれた光源と P に位置する、側面鏡によって得られるその光源の像と の間の間隔は、上述の計算方法を演繹して得られる。そして、位置 Pと位置 P は、 互いに側面鏡による鏡像の関係にあるので、側面鏡の鏡面を、位置 Pと位置 P と の間の間隔の半分の位置に設けている。更に、上述の計算方法を演繹して位置 P と位置 P との間の間隔、…、位置 P と位置 P との間の間隔を求めると、位置 P 0 1 η The positions of the arranged light source images (virtual light source VLS) are 光源, Ρ, · '· Ρ. Here, the distance between the light source located at Ρ n + 1 n + 2 2n + ln and the image of that light source obtained by the side mirror located at P is obtained by deducting the above calculation method . Since the position P and the position P are in a mirror image relationship with the side mirror, the mirror surface of the side mirror is provided at a position half the distance between the position P and the position P. Furthermore, when the above calculation method is deduced and the interval between the position P and the position P, and the interval between the position P and the position P are obtained, the position P
1 n + 2 2n 2n+ l 1 n + 2 2n 2n + l
、位置 P との間の間隔、位置 P と位置 P との間の間隔、…、と進むにつれ n+ 1 n+ 2 n+ 2 n+ 3  , The distance between the position P, the distance between the position P and the position P, ..., as you proceed, n + 1 n + 2 n + 2 n + 3
て間隔が狭くする必要があるが、図 24に示す配置では鏡面による虚像であるため逆 に間隔が広くなつてしまう（当然、位置 P と位置 P との間の間隔、…、位置 P と  However, in the arrangement shown in Fig. 24, the interval is wide because it is a virtual image with a mirror surface (naturally, the interval between position P and position P, ..., position P and
n+ 1 n + 2 2n 位置 P との間の間隔は、それぞれ、位置 と位置 Pとの間の間隔、 · · ·、位置 P n + 1 n + 2 2n The distance from position P is the distance between position and position P, respectively.
2n+ l Pn- 1 n 0 と位置 Pとの間の間隔に一致している）。なお、 n番目の光源の外側に設けられる側 面鏡と対をなす側面鏡が、撮像対象領域 (Ai)の中心線 (結像レンズの光軸）に対し て上半分の領域にも設けられ (PM2の位置）、 n番目の光源の外側に設けられる側 面鏡とは、互いに平行に配置される。このため、側面鏡の対によって、鏡像である無 限の数の虚光源が生じる力 S、この内、側面鏡で 2回以上の反射で生ずる虚光源は、 撮像対象領域 (Ai)からかなり離れた位置に生じため、撮像対象領域 (Ai)における 照度分布（Di)に対する寄与率が、著しく小さぐ無視してもなんら差し支えない。 2n + l Pn- 1 n 0 corresponds to the interval between position P). A side mirror that is paired with the side mirror provided outside the nth light source is also provided in the upper half of the center line of the imaging target area (Ai) (the optical axis of the imaging lens). (Position of PM2) The side mirrors provided outside the nth light source are arranged in parallel to each other. For this reason, the force S that generates an unlimited number of virtual light sources that are mirror images by the pair of side mirrors, of which the virtual light source that is generated by two or more reflections by the side mirrors is far from the imaging target area (Ai). Therefore, the contribution ratio to the illuminance distribution (Di) in the imaging target area (Ai) is extremely small and can be ignored.
[0241] 次に、複数の光源によって照明される撮像対象領域 (Ai)のある任意の点 Mmにお ける相対照度 I (Mm)を求めることにする。撮像対象領域 (Ai)に対する鉛直線と、光 源から点 Mmに向力、つて放出される光の放射ベクトルの角度を αとすると、光源から 撮像対象領域 (Ai)までの距離が、 L0であるので、ある一つの光源から点 Mmまでの 距離は、 LO/cos aとなる。そして、副走査方向（Sy)においては光源から放出され る光の光束が発散しないことを前提とすると、各光源から放出される光によって照明 される撮像対象領域 (Ai)の点 Mmにおける光の強度は、各光源から点 Mmまでの 距離 LO/cos aに逆比例する。さらに、その同一点 Mmでの面の傾きによる受ける 光束の減少度は cos aとなる。 Next, the relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) illuminated by a plurality of light sources is determined. If the angle of the vertical line to the imaging target area (Ai) and the directional force of the light source from the light source to the point Mm and the radiation vector of the emitted light is α, the distance from the light source to the imaging target area (Ai) is L0. Therefore, the distance from one light source to the point Mm is LO / cos a. Assuming that the light beam emitted from the light source does not diverge in the sub-scanning direction (Sy), the light at point Mm in the imaging target area (Ai) illuminated by the light emitted from each light source Intensity from each light source to point Mm Inversely proportional to the distance LO / cos a. Furthermore, the degree of decrease in luminous flux due to the tilt of the surface at the same point Mm is cos a.
一方、図 24 (b)に示すように、撮像対象領域 (Ai)に対する鉛直線と角度 αをなす 放射ベクトルの方向に光源から放出される光の強度は、光源から放出される光の放 射ベクトルの分布（エンベロープ）に依存する。現実の LEDなどの光源の放射べタト ル分布 (エンベロープ）は複雑な形を成しているが、計算の都合上円形ないしは楕円 状で近似する。例えば、図 24 (b)の（1 )に示すように、光源から放出される光の放射 ベクトルのエンベロープが円形に近似できる場合には、光源の中心軸に対して角度 aをなす放射ベクトルの方向に光源から放出される光の強度は、 cos aだけ減少す る。光源から放出される光の放射ベクトルのエンベロープが、楕円状に近似できる場 合には、その放射ベクトルのエンベロープの形状により、図 24 (b)の（2)に示すような cos2 a、あるいは、図 24 (b)の（3)に示すような cos4 a等のように近似することが可能 である。 On the other hand, as shown in FIG. 24 (b), the intensity of the light emitted from the light source in the direction of the radiation vector that forms an angle α with the vertical line with respect to the imaging target area (Ai) is the emission of the light emitted from the light source. Depends on vector distribution (envelope). The radiation vector distribution (envelope) of a light source such as an actual LED has a complicated shape, but it is approximated by a circle or ellipse for convenience of calculation. For example, as shown in (1) of Fig. 24 (b), when the envelope of the radiation vector of the light emitted from the light source can be approximated to a circle, the radiation vector forming an angle a with respect to the central axis of the light source The intensity of light emitted from the light source in the direction decreases by cos a. If the envelope of the radiation vector of light emitted from the light source can be approximated to an ellipse, depending on the shape of the envelope of the radiation vector, cos 2 a as shown in (2) of Fig. 24 (b), or It can be approximated as cos 4 a as shown in (3) of Fig. 24 (b).
[0242] 従って、複数の光源によって照明される撮像対象領域 (Ai)のある任意の点 Mmに おける相対照度 I (Mm)は、  [0242] Therefore, the relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) illuminated by a plurality of light sources is
[0243] [数 18] l Mm) = Ak - cos2 a、' ' cos— ak (た/ fし、 ≤ak≤―) [0243] [Equation 18] l Mm) = A k -cos 2 a, '' cos— a k (/ f and ≤a k ≤―)
=o 2  = o 2
[0244] によって表される。ここで、 Aは、 k番目の光源が放出する光の総光量の相対値であ k [0244] Where A is the relative value of the total amount of light emitted by the kth light source.
り、 α は、結像レンズ光軸の方向に対する点 Mmに向力、う k番目の光源の放射べタト k  Α is the direction force at the point Mm with respect to the direction of the optical axis of the imaging lens, and the radiation plate k of the kth light source
ルの角度である。また、 aは、その光源の放射ベクトルのエンベロープを近似する係 数である。例えば、光源の放射ベクトルのエンベロープが、円形に近い場合には、図 24 (b)の（1 )に示すように、 a = lとし、光源の放射ベクトルのエンベロープが、楕円 状に近い場合には、図 24 (b)の（2)及び（3)に示す a = 2及び a = 3のように、 a〉lと する。また、光源の放射ベクトルのエンベロープが偏平していれば a < lに近似できる  It is the angle of the le. A is a coefficient approximating the envelope of the radiation vector of the light source. For example, if the envelope of the radiation vector of the light source is close to a circle, a = l and the envelope of the radiation vector of the light source is close to an ellipse as shown in (1) of Fig. 24 (b). Is a> l, as in a = 2 and a = 3 shown in (2) and (3) of Fig. 24 (b). If the envelope of the radiation vector of the light source is flat, it can approximate a <l
[0245] このようにして、撮像対象領域 (Ai)の中心線 (CL)から下半分に配置した光源の全 体によって照明される撮像対象領域 (Ai)の全域にわたる照度分布を算出することが できる。また、得られた照度分布を中心線 (CUに対して対称に反転させれば、撮像 対象領域 (Ai)の中心線 (CUから上半分に配置した光源の全体によつて照明される 撮像対象領域 (Ai)の全域にわたる照度分布を得ることができる。そして、撮像対象 領域 (Ai)の中心線 (CUから下半分に配置した光源の全体によつて照明される撮像 対象領域 (Ai)の全域にわたる照度分布と撮像対象領域 (Ai)の中心線 (CUから上 半分に配置した光源の全体によつて照明される撮像対象領域 (Ai)の全域にわたる 照度分布を加算すれば、全部の光源によって照明される撮像対象領域 (Ai)の全域 にわたる照度分布を得ることができる。ただし、この計算をする場合、 P上に置いた [0245] In this way, it is possible to calculate the illuminance distribution over the entire area of the imaging target area (Ai) illuminated by the entire light source arranged in the lower half from the center line (CL) of the imaging target area (Ai). it can. In addition, if the obtained illuminance distribution is inverted symmetrically with respect to the CU, the center line of the imaging target area (Ai) (illuminated by the entire light source placed in the upper half of the CU Illuminance distribution over the entire area (Ai) can be obtained, and the center line of the imaging target area (Ai) (the imaging target area (Ai) illuminated by the entire light source placed in the lower half from the CU) By adding the illuminance distribution over the entire area and the center line of the imaging target area (Ai) (the illuminance distribution over the entire imaging target area (Ai) illuminated by the entire light source placed in the upper half from the CU, all the light sources It is possible to obtain the illuminance distribution over the entire area of the imaging target area (Ai) illuminated by
0  0
光源から発する光束は中心線 (CUから下半分を計算する場合と、上半分を計算す る場合の両者で用いるので、その光源の相対強度 Aを、その以外の位置に置いた  The luminous flux emitted from the light source is used for both the center line (when calculating the lower half from the CU and when calculating the upper half, so the relative intensity A of the light source was placed at other positions.
0  0
光源の相対強度の 1/2として計算する必要がある。  It is necessary to calculate as 1/2 of the relative intensity of the light source.
[0246] そこで、このようなモデルで得られる相対照度を撮像対象領域 (Ai)の全域にわたつ て計算する。 [0246] Therefore, the relative illuminance obtained by such a model is calculated over the entire area to be imaged (Ai).
[0247] 従来、実用的な縮小光学系は、結像レンズによる像の歪みや明度分布の関係から W:Ld=l:l.5力、ら W:Ld=l:lの範囲で用いられてきた。 W:Ld=l:l.5の場合 には、 6max=18.4° となり、 W:Ld=l： 1の場合には、 6max = 26.6° となる。 図 25は、これらの実用的な縮小光学系を用いた場合、一定照度で照明された撮像 対象領域 (Ai)を結像レンズによって一次元 CCD上に結像される画像の相対明度の 具体例、及び、一次元 CCD上に結像される画像の相対明度が一定になるように撮 像対象領域 (Ai)を照明する場合の目標照度分布（要求照度分布）の具体例を示す 図である。  [0247] Conventionally, a practical reduction optical system has been used in the range of W: Ld = l: l.5 force, W: Ld = l: l due to the relationship between image distortion caused by the imaging lens and brightness distribution. I came. In the case of W: Ld = l: l.5, 6max = 18.4 °, and in the case of W: Ld = l: 1, 6max = 26.6 °. Figure 25 shows a specific example of the relative brightness of an image that is imaged on a one-dimensional CCD by an imaging lens with the imaging target area (Ai) illuminated at a constant illuminance when these practical reduction optical systems are used. FIG. 5 is a diagram showing a specific example of a target illuminance distribution (required illuminance distribution) when illuminating the imaging target area (Ai) so that the relative brightness of an image formed on the one-dimensional CCD is constant. .
W:Ld=l:l.5の場合における、撮像対象領域 (Ai)内の各位置に対応する一次 元 CCD上に結像レンズによって結像される画像の相対明度の曲線は、図 25におけ る（1)に示す曲線のようになる。また、 W:Ld=l： 1の場合における、撮像対象領域（ Ai)内の各位置に対応する一次元 CCD上に結像レンズによって結像される画像の 相対明度の曲線は、図 25における（2)に示す曲線のようになる。その結果、 W:Ld = 1:1.5の場合における、撮像対象領域 (Ai)の中心における照度に対して、撮像 対象領域 (Ai)のあらゆる位置で要求される照度の割合の曲線は、図 25の（3)に示 す曲線のようになり、その撮像対象領域 (Ai)の中心における照度に対して、撮像対 象領域 (Ai)の両端における向上させなければならない照度の程度は、 123%である 。また、 W : Ld= l： 1の場合における、撮像対象領域 (Ai)の中心における照度に対 して、撮像対象領域 (Ai)のあらゆる位置で要求される照度の割合の曲線は、図 25の (4)に示す曲線のようになり、その撮像対象領域 (Ai)の中心における照度に対して、 撮像対象領域 (Ai)の両端における向上させなければならない照度の程度は、 156 %である。 The curve of the relative brightness of the image formed by the imaging lens on the one-dimensional CCD corresponding to each position in the imaging target area (Ai) in the case of W: Ld = l: l.5 is shown in FIG. It looks like the curve shown in (1). In addition, in the case of W: Ld = 1, the relative brightness curve of the image formed by the imaging lens on the one-dimensional CCD corresponding to each position in the imaging target area (Ai) is shown in FIG. It looks like the curve shown in (2). As a result, when W: Ld = 1: 1.5, the curve of the ratio of illuminance required at any position of the imaging target area (Ai) to the illuminance at the center of the imaging target area (Ai) is shown in Fig. 25. Shown in (3) The degree of illuminance that must be improved at both ends of the imaging target area (Ai) is 123% with respect to the illuminance at the center of the imaging target area (Ai). In addition, in the case of W: Ld = l: 1, the illuminance ratio curve required at every position of the imaging target area (Ai) with respect to the illuminance at the center of the imaging target area (Ai) is shown in FIG. The degree of illuminance that must be improved at both ends of the imaging target area (Ai) is 156% with respect to the illuminance at the center of the imaging target area (Ai). .
[0248] 図 26は、これまでに述べた考え方に従って撮像対象領域 (Ai)を照明する目標相 対照度に向けてシミュレーションした結果を示す図である。即ち、上述した式によって 求められる相対照度 I (Mm)の値、及び、その相対照度 I (Mm)と要求される相対照 度との差分を、 A = 1、N= 12 (撮像対象領域 (Ai)の全域を照明する光源の数 = 2 k  [0248] FIG. 26 is a diagram illustrating a result of simulation toward a target contrast degree for illuminating the imaging target area (Ai) according to the above-described concept. That is, the value of the relative illuminance I (Mm) obtained by the above-described equation and the difference between the relative illuminance I (Mm) and the required contrast level are expressed as A = 1, N = 12 (imaging target region ( Number of light sources that illuminate the entire area of Ai) = 2 k
5個）、及び、 a = 2の条件で計算した。ただし、図 26 (a)は、 W : Ld= l : lの場合にお ける結果のみを表示している。図 26 (b)は、相対照度 I (Mm)の計算結果と要求され る相対照度との差分を示す図（拡大図）である。  5) and a = 2. However, Fig. 26 (a) shows only the results when W: Ld = l: l. Figure 26 (b) is a diagram (enlarged view) showing the difference between the calculated relative illuminance I (Mm) and the required relative illuminance.
[0249] また、図 26 (a)において、グラフ（1)は、中心線（CU力、ら半分の領域における光源 によって照明される撮像対象領域 (Ai)全域での照度分布を示し、グラフ（2)は、ダラ フ（1)の反対側の半分の領域における光源によって照明される撮像対象領域 (Ai) 全域での照度分布を示す。グラフ（3)は、グラフ（1)とグラフ（2)との和である。グラフ (4)は グラフ（3)の中央の値が 100になるように正規化したものである。グラフ（5)は 、図 26 (a)のグラフ（4)と図 25のグラフ（4)との差分である。  [0249] In addition, in Fig. 26 (a), the graph (1) shows the illuminance distribution in the entire area to be imaged (Ai) illuminated by the light source in the center line (CU force, half area). 2) shows the illuminance distribution over the entire area to be imaged (Ai) illuminated by the light source in the other half of the area on the opposite side of the graph (1) .Graph (3) shows the graphs (1) and (2 Graph (4) is normalized so that the center value of graph (3) is 100. Graph (5) is the same as graph (4) and Fig. 26 (a). This is the difference from graph (4) in Fig. 25.
[0250] 図 26 (b)において、グラフ（6)は、グラフ（5)と同一であり、グラフ（7)は、 W : Ld= l  [0250] In Fig. 26 (b), graph (6) is the same as graph (5), and graph (7) is W: Ld = l
: 1. 5の場合における相対照度の計算値と目標照度との差分である。  : 1.5 The difference between the calculated relative illuminance and the target illuminance in the case of 5.
[0251] 図 26 (b)に示すグラフの両端付近が乱れて目標照度との差分が多く発生している 理由は、図 24に示すように位置 P 力 位置 P までの光源が、位置 Pから位置  [0251] The reason for the large difference between the target illuminance and the vicinity of both ends of the graph shown in Fig. 26 (b) is that the light source up to position P force position P is Position
n+ 1 2n+ l 0  n + 1 2n + l 0
Pまでの光源の鏡像である虚光源であるので、光源の間の間隔を理想的な間隔にし て!/、な!/、ためである。ただし、位置 Pと位置 P の間における側面鏡の位置を若干 P 側に接近させたり、側面鏡の角度を微妙に変化させたり、適切に設定することによつ て、撮像対象領域 (Ai)の両端付近における照度分布をある程度制御することができ [0252] しかしながら、グラフ（7)に示される差分は、 ± 1 (%)未満であり、グラフ（6)で示さ れる差分も、 ± 2 (%)未満である。すなわち、複数の光源によって照明される撮像対 象領域 (Ai)の相対照度を、非常に精度よく目標の照度分布に近づけることが可能で あること力 Sわ力、る。また、図 26 (b)のグラフから、主走査方向（Sx)における、光源によ つて照明する領域の幅を 2〜3%程度増加させる（又は、主走査方向（Sx)における、 光源によって照明される撮像対象領域 (Ai)の幅を 2〜3%程度減少させる）ことによ つて、光源によって照明される撮像対象領域 (Ai)の照度分布を、 目標の照度分布に さらに適合させることが可能であり、適切な条件を設定することによって、光源によつ て照明される撮像対象領域 (Ai)の照度分布と目標の照度分布との差分を、 ± 1 %未 満にすることが可能である。ただし、実用上は、部品の精度や組み立て精度の誤差 などによる照度分布の変動が、上記の差分よりも大きぐ上記の差分程度は、あまり 問題ではない。 Because it is a virtual light source that is a mirror image of the light source up to P, the ideal distance between the light sources! However, if the position of the side mirror between position P and position P is slightly closer to the P side, or the angle of the side mirror is slightly changed or set appropriately, the imaging target area (Ai) The illuminance distribution near both ends of the [0252] However, the difference shown in the graph (7) is less than ± 1 (%), and the difference shown in the graph (6) is also less than ± 2 (%). That is, the relative illuminance of the imaging target area (Ai) illuminated by a plurality of light sources can be brought close to the target illuminance distribution with very high accuracy. In addition, from the graph of FIG. 26 (b), the width of the area illuminated by the light source in the main scanning direction (Sx) is increased by about 2 to 3% (or illumination by the light source in the main scanning direction (Sx)). By reducing the width of the imaging target area (Ai) to be reduced by about 2 to 3%), the illuminance distribution of the imaging target area (Ai) illuminated by the light source can be further adapted to the target illuminance distribution. Yes, by setting appropriate conditions, the difference between the illuminance distribution of the imaging target area (Ai) illuminated by the light source and the target illuminance distribution can be less than ± 1%. It is. However, in practical use, the above-mentioned difference in which the fluctuation of the illuminance distribution due to errors in parts accuracy or assembly accuracy is larger than the above difference is not a problem.
[0253] また、図 26 (b)におけるグラフ（6)及び（7)の比較から、主走査方向（Sx)における 撮像対象領域 (Ai)の幅 Wに対する撮像対象領域 (Ai)から結像レンズまでの距離 L dの比が、より大きいほど、容易に目標照度分布に近づけられることが分る。  [0253] From the comparison of graphs (6) and (7) in Fig. 26 (b), the imaging lens from the imaging target area (Ai) to the width W of the imaging target area (Ai) in the main scanning direction (Sx) It can be seen that the larger the ratio of the distance Ld to is, the closer it is to the target illuminance distribution.
[0254] さらに、光源の放射べタトノレのエンベロープをモデル化する cosa aにおける aを、 a = 1又は a = 4に設定して、同様のシミュレーションをした場合に、照明対象面（撮像 領域）（Ai)から光源までの最適距離 LOが、多少変化するものの、ほぼ同様の特性が 得られた。 [0254] Furthermore, if a is set to a = 1 or a = 4 and cos a a that models the envelope of the light source's radiation beta is set to a = 1 or a = 4, the surface to be illuminated (imaging area) Although the optimum distance LO from (Ai) to the light source slightly changed, almost the same characteristics were obtained.
[0255] 加えて、ここでは、撮像対象領域 (Ai)の中心線上に光源を置き、撮像対象領域 (A i)の全域を、奇数個の光源で照明することを前提にしたが、撮像対象領域 (Ai)の中 心線上に光源を置かずに、照明対象領域 (Ai)の全域を、偶数個の光源で照明する こともでき、同様のシミュレーション又は設計も可能であることは言うまでもない。  [0255] In addition, here, it is assumed that a light source is placed on the center line of the imaging target area (Ai) and the entire imaging target area (A i) is illuminated with an odd number of light sources. It goes without saying that the entire illumination target area (Ai) can be illuminated with an even number of light sources without placing a light source on the center line of the area (Ai), and a similar simulation or design is possible.
[0256] 次に、複数の光源の間隔を調整することによって、撮像対象領域 (Ai)を照明する 光の照度分布を 1/cos4 Θの特性に一致させる照明装置の一例を示す。 Next, an example of an illuminating device that matches the illuminance distribution of the light that illuminates the imaging target area (Ai) with the 1 / cos 4 Θ characteristic by adjusting the interval between the plurality of light sources will be described.
[0257] 図 27は、複数の光源の間隔を調整することによって、撮像対象領域 (Ai)を照明す る光の照度分布を 1/cos4 Θの特性に一致させる照明装置を実現するための概念 図である。図 27 (a)は、複数の光源の間隔を調整することによって、撮像対象領域（ Ai)を照明する光の照度分布を 1/cos4 Θの特性に一致させる照明装置の例の上面 図であり、撮像対象領域 (Ai)の周辺部の一方を示したものである（中心部からもう一 方の周辺部は省略している）。図 27 (b)は、複数の光源の間隔を調整することによつ て、撮像領域 (撮像対象領域）（Ai)を照明する光の照度分布を 1/cos4 Θの特性に 一致させる照明装置の例の正面図である。 [0257] Figure 27 is a diagram for realizing an illuminating device that matches the illuminance distribution of the light that illuminates the imaging target area (Ai) with the 1 / cos 4 Θ characteristic by adjusting the interval between the plurality of light sources. concept FIG. Fig. 27 (a) is a top view of an example of an illuminating device that matches the illuminance distribution of the light that illuminates the imaging target area (Ai) to the 1 / cos 4 Θ characteristic by adjusting the interval between the multiple light sources. Yes, it shows one of the peripheral parts of the imaging target area (Ai) (the other peripheral part from the central part is omitted). Figure 27 (b) shows an illumination that matches the illuminance distribution of the light that illuminates the imaging area (imaging target area) (Ai) with the 1 / cos 4 Θ characteristic by adjusting the interval between the multiple light sources. It is a front view of the example of an apparatus.
[0258] 図 27 (a)に示すように、照明装置は、複数の光源として、主走査方向（Sx)に配列 させられた複数の LEDを含む。個々の LEDから放出される光の光束を、その LED に対応する凸レンズであるフードレンズによって平行光にした後、シリンダレンズであ る照明レンズ (3)によって一旦、集光させた後、発散させることによって、照明対象領 域 (Ai)を照明する。ここで、複数の LEDの間隔は、上述のシミュレーションの結果に 従って、照明装置の中心線付近から照明装置の周辺に向かって、狭くなるように、複 数の LEDが、配置してある。 （図 27 (a)における LEDの間隔 wの番号 kの順序は、 k [0258] As shown in Fig. 27 (a), the illumination device includes a plurality of LEDs arranged in the main scanning direction (Sx) as a plurality of light sources. The luminous flux of light emitted from each LED is collimated by a hood lens that is a convex lens corresponding to the LED, then condensed once by an illumination lens (3) that is a cylinder lens, and then diverged. As a result, the illumination target area (Ai) is illuminated. Here, the plurality of LEDs are arranged so that the interval between the plurality of LEDs becomes narrower from the vicinity of the center line of the lighting device toward the periphery of the lighting device in accordance with the result of the above simulation. (The order of the number k of the LED spacing w in Fig. 27 (a) is k
図 23における間隔 wの番号 kの順序と逆である。）なお、図 24に示される撮像対象 k  This is the reverse of the order of number k in interval w in Fig. 23. Note that the imaging target k shown in Fig. 24
領域 (Ai)から距離 L0だけ離れた各光源の位置 P〜Pは、図 27 (a)に示す照明装  The positions P to P of the respective light sources that are separated from the area (Ai) by the distance L0 are the illumination devices shown in FIG.
0 n  0 n
置においては、各 LEDに対応するシリンダレンズの焦点の位置（焦点距離 f)に対応 する。すなわち、各 LEDに対応するシリンダレンズの焦点の位置は、仮想的な光源 の位置とみなすことができる。  The position corresponds to the focal position (focal length f) of the cylinder lens corresponding to each LED. In other words, the focus position of the cylinder lens corresponding to each LED can be regarded as a virtual light source position.
[0259] また、この第 11の実施例での照明装置の副走査方向（Sy)における構成は、副走 查方向（Sy)における本発明の第 1〜9の実施例での照明装置の構成を変更する必 要はない。図 27 (b)には、個々の LEDから放出された光の光束を、その LEDに対応 するフードレンズで平行光にされた後、シリンダレンズである照明レンズ (3)を平行光 のまま透過し、集束ミラー（4b)によって照明対象領域 (Ai)に集束される方法を示し ている。ここで、集束ミラーの代わりに平面鏡を用いて平行光のまま撮像対象領域 (A i)を照射するようにしても上述のシミュレーションの結果から外れるものではないことを 付記しておく。 [0259] The configuration of the illumination device in the eleventh embodiment in the sub-scanning direction (Sy) is the same as that of the illumination device in the first to ninth embodiments of the present invention in the sub-scanning direction (Sy). There is no need to change. In Fig. 27 (b), the light flux emitted from each LED is converted into parallel light by the hood lens corresponding to the LED, and then transmitted through the illumination lens (3), which is a cylinder lens, as parallel light. The method of focusing on the illumination target area (Ai) by the focusing mirror (4b) is shown. Here, it should be noted that even if a plane mirror is used instead of the focusing mirror to irradiate the imaging target area (Ai) as parallel light, it does not deviate from the results of the above simulation.
[0260] なお、図 27においては、光源の LEDから放出された光を平行光にする手段として 、凸レンズであるフードレンズを用いたが、フードレンズの代わりに、図 9に示すような 回転放物面鏡を用いてもよ!/、。 In FIG. 27, a hood lens that is a convex lens is used as a means for collimating the light emitted from the LED of the light source. Instead of the hood lens, as shown in FIG. You can use a rotating parabolic mirror!
[0261] また、本発明の第 1〜9の実施例の方法又は装置の構成において、主走査方向（S X)に配置された複数の光源の間隔を、上述したようなシミュレーションの結果に従つ て、変更してもよい。 [0261] In the methods or apparatus configurations of the first to ninth embodiments of the present invention, the intervals between the plurality of light sources arranged in the main scanning direction (SX) are set according to the simulation results as described above. It may be changed.
[0262] さらに、本発明の第 5及び 6の実施例においては、赤色 (R)、緑色（G)、青色（B)の LEDの組みを光源としている。本発明の第 11の実施例においても、同様にして、そ の赤色（R)、緑色（G)、青色（B)の LEDの組みの間隔を、上述したシミュレーション の結果に従って、変更すればよい。  [0262] Furthermore, in the fifth and sixth embodiments of the present invention, a set of red (R), green (G), and blue (B) LEDs is used as a light source. Similarly, in the eleventh embodiment of the present invention, the interval between the red (R), green (G), and blue (B) LED pairs may be changed according to the simulation results described above. .
実施例 12  Example 12
[0263] 本発明の第 12の実施例は、複数の光源の各々から撮像対象領域 (Ai)までの距離 を調整して撮像対象領域 (Ai)を照明する光の照度分布を 1/cos4 Θの特性に一致 させる例を示す。 [0263] In the twelfth embodiment of the present invention, the illuminance distribution of light that illuminates the imaging target area (Ai) by adjusting the distance from each of the plurality of light sources to the imaging target area (Ai) is 1 / cos 4 An example of matching with the characteristic of Θ is shown.
[0264] 図 28は、一次元 CCDに結像される画像の相対明度が一定となるような、撮像対象 領域 (Ai)を照明する複数の光源の具体的な配置の求め方を説明する図である。図 28 (a)は、複数の光源の配置及び側面鏡を配置する鏡面の位置を示す図であり、図 28 (b)は、光源の放射特性の例を示す図である。  [0264] FIG. 28 is a diagram for explaining how to obtain a specific arrangement of a plurality of light sources that illuminate the imaging target area (Ai) so that the relative brightness of the image formed on the one-dimensional CCD is constant. It is. FIG. 28A is a diagram showing the arrangement of a plurality of light sources and the position of the mirror surface on which the side mirror is arranged, and FIG. 28B is a diagram showing an example of the radiation characteristics of the light sources.
[0265] 図 28 (a)に示す図においては、主走査方向（Sx)における複数の光源の間隔は、 一定であるが、複数の光源の各々から照明対象領域 (撮像対象領域）（Ai)までの距 離を変化させる。図 28における記号は、図 24における記号と同一である力 図 28 (a )においては、複数の光源の間隔 wl , w2,•••wnii,一定であり、 Wh/Nに等しい。 言い換えれば、複数の光源の間隔 wl , w2,•••wntt,主走査方向（Sx)における撮 像対象領域 (Ai)の長さの半分 Whを N等分することによって与えられる。また、複数 の光源のうち、 k番目の位置 Pに配置される光源から照明対象面（撮像領域）（Ai)ま  In the diagram shown in FIG. 28 (a), the interval between the plurality of light sources in the main scanning direction (Sx) is constant, but the illumination target region (imaging target region) (Ai) from each of the plurality of light sources Change the distance to. The symbol in FIG. 28 is the same force as the symbol in FIG. 24. In FIG. 28 (a), the intervals between the plurality of light sources wl, w2, ••• wnii are constant and equal to Wh / N. In other words, the intervals wl, w2, •• wntt of a plurality of light sources, and half the length Wh of the imaging target area (Ai) in the main scanning direction (Sx) are given by N. In addition, among the plurality of light sources, the light source arranged at the kth position P to the illumination target surface (imaging area) (Ai).
k  k
での距離 Lは、次式  The distance L at
k  k
[0266] [数 19] = 0 X cos4 ¾ [0266] [Equation 19] = 0 X cos 4 ¾
[0267] に従って決められる。ここで、 Θ は、結像レンズの光軸に対する、結像レンズの中心 と撮像対象領域 (Ai)上の k番目の分割点とを結ぶ直線の角度である。すなわち、複 数の光源のうち k番目の位置 Pに配置される光源から照明対象面（撮像領域）（Ai) Determined according to [0267]. Where Θ is the center of the imaging lens relative to the optical axis of the imaging lens Is an angle of a straight line connecting the kth division point on the imaging target area (Ai). That is, the illumination target surface (imaging area) (Ai) from the light source arranged at the kth position P among the plurality of light sources.
k  k
までの距離 Lkは、 Θ に対してコサイン四乗則に従った、結像レンズによって結像さ  The distance Lk to is imaged by the imaging lens according to the cosine fourth law with respect to Θ.
k  k
れる画像の明度の減少を、結像レンズの光軸上に設けられた光源の位置 Pから撮像  The decrease in brightness of the captured image is captured from the position P of the light source provided on the optical axis of the imaging lens.
0 対象領域 (Ai)までの距離 Lを距離 Lまで減少させることによって補償する。  0 Compensate by reducing the distance L to the target area (Ai) to the distance L.
0 k  0 k
[0268] また、複数の光源から放出される光によって照射される撮像対象領域 (Ai)におけ る任意の点 Mmでの相対照度 I (Mm)は、本発明の第 1 1の実施例と同様の考え方 で、式  [0268] The relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) irradiated with light emitted from a plurality of light sources is the same as that in the first embodiment of the present invention. In the same way, the formula
[0269] [数 20] π 7i  [0269] [Equation 20] π 7i
I(Mm) = > Ak - (L0 /Lk y - cos2 ah - c a ak ( 7こ7こし、 —— < ak <―) I (Mm) => A k- (L 0 / L k y-cos 2 a h -c a a k (7 to 7 strains, —— <a k <-)
[0270] によって求められる。 [0270].
[0271] 図 29は、本発明の第 12の実施例以降の実施例における相対照度についてのシミ ユレーシヨン結果のうち、相対照度 I (Mm)の計算結果と要求される相対照度との差 分を示す図である。  FIG. 29 shows the difference between the calculation result of relative illuminance I (Mm) and the required relative illuminance among the simulation results of relative illuminance in the twelfth and subsequent embodiments of the present invention. FIG.
[0272] 本発明の第 12の実施例中、以上に示した条件の下で、本発明の第 1 1の実施例と 同様の方法により、 W : Ld = l : 1の条件の下で、複数の光源によって照明される撮像 対象領域 (Ai)の全域にわたる照度分布のシミュレーションを行った。その結果、図 2 6と同様のグラフを得ることができた。この内、シミュレーションの結果による照度分布 を示すグラフは、図 26の（a)のグラフと見分けがつかない程度に酷似しているので提 示を省略し、照度分布と目標の照度分布との差分の拡大図のみを、図 29中の（1 )の 曲泉に示す。  [0272] In the twelfth embodiment of the present invention, under the conditions described above, the same method as in the first embodiment of the present invention, under the condition of W: Ld = l: 1, The illuminance distribution was simulated over the entire area to be imaged (Ai) illuminated by multiple light sources. As a result, a graph similar to that shown in FIG. 26 was obtained. Of these, the graph showing the illuminance distribution based on the simulation results is so similar that it cannot be distinguished from the graph in Fig. 26 (a), so the presentation is omitted and the difference between the illuminance distribution and the target illuminance distribution is omitted. Only the enlarged view of (1) is shown in Fig. 29.
[0273] 図 29中の（1 )の曲線の両端付近が乱れて目標照度との差分が多く発生している理 由は、実施例 12の理由と似たような理由で、位置 P 力も位置 P までの光源が、  [0273] The reason why the vicinity of both ends of the curve (1) in Fig. 29 is disturbed and the difference from the target illuminance is large is similar to the reason of Example 12, and the position P force is also the position. Light sources up to P
n+ 1 2n+ l  n + 1 2n + l
位置 P力も位置 Pまでの光源の鏡像である虚光源であるので、撮像対象領域 (Ai) Since the position P force is also a virtual light source that is a mirror image of the light source up to position P, the imaging target area (Ai)
0 n 0 n
と光源までの距離を理想的な距離に設定できないためである。ただし、位置 Pと位置 P の間における側面鏡の位置を若干 P側に接近させたり、側面鏡の角度を微妙 に変化させたり、適切に設定することによって、撮像対象領域 (Ai)の両端付近にお ける照度分布をある程度制御することができる。 This is because the distance to the light source cannot be set to an ideal distance. However, if the position of the side mirror between position P and position P is slightly closer to the P side, or the angle of the side mirror is slightly changed or set appropriately, near the ends of the imaging target area (Ai) In The illuminance distribution can be controlled to some extent.
しかしながら、このままでも、図 29のグラフ（1)に示される差分の最大値は、 ± 3% 程度であり、図 26に示される差分の最大値の約 2倍程度である力 S、部品の精度や組 み立ての精度の観点及び省エネルギーの観点の!/、ずれからも殆ど問題とならなレ、。 (一次元 CCDで光量を電気信号に変換した後の電気信号の増幅率を変えてその差 分を補正しても、その増幅率の変更は小さぐノイズの影響を受けることはない。 ) 次に、以上の考え方で照明装置化するための考え方を示す。  However, the maximum value of the difference shown in graph (1) in Fig. 29 is about ± 3%, even if this is the case. The force S, which is about twice the maximum value of the difference shown in Fig. 26, and the accuracy of the parts From the point of view of assembly accuracy and energy saving! (Even if you change the amplification factor of the electrical signal after converting the light amount into an electrical signal with a one-dimensional CCD and correct the difference, the change in the amplification factor is not affected by the small noise.) Next Shows the concept for making the lighting device based on the above concept.
[0274] 図 30は、複数の光源の各々から撮像領域 (撮像対象領域）（Ai)までの距離を調整 することによって、撮像領域 (Ai)を照明する光の照度分布を l/cos4 6の特性に一 致させる照明装置を実現するための概念図である。図 30 (a)は、その上面図であり、 図 30 (b)は、その正面図である。なお、図 30に示す概念を装置化して第 1走行体に 搭載する方法は、前述の実施例 11の方法に準じており、当業者には容易に実施可 能である。 [0274] FIG. 30 is by adjusting the distance from each of the plurality of light sources to the imaging area (imaging target region) (Ai), the illuminance distribution of the light illuminating the imaging area (Ai) l / cos 4 6 It is a conceptual diagram for implement | achieving the illuminating device matched with the characteristic of this. FIG. 30 (a) is a top view thereof, and FIG. 30 (b) is a front view thereof. Note that the method of embodying the concept shown in FIG. 30 and mounting it on the first traveling body is in accordance with the method of Example 11 described above, and can be easily implemented by those skilled in the art.
[0275] 図 31は、光源から放出される光の放射特性を変化させる方法の例を説明する図で ある。図 31は、図 30 (a)に示す上面図の方向と同じ方向から見た図である。図 31に おいては、正面図は、省略するが、図 30 (b)と同様の構成を示す。  FIG. 31 is a diagram for explaining an example of a method for changing the radiation characteristic of light emitted from a light source. FIG. 31 is a view seen from the same direction as the top view shown in FIG. In FIG. 31, the front view is omitted, but the same configuration as FIG. 30 (b) is shown.
[0276] ここで、図 31の（1)に示すように、フードでもある凸レンズ (焦点距離 fO)の焦点の 位置に発光源 LEDを置く。また、その凸レンズと同じ焦点距離を有する凸シリンダレ ンズ (焦点距離 fl)を、凸レンズの前面に、凸レンズの光軸と凸シリンダレンズの光軸 を一致させるように、配置する。このとき、その凸シリンダレンズの焦点位置に、発光 源の放射特性と同様の放射特性を有する仮想の光源を形成することとができる。例 えば、図 28 (b)の（1)のように、発光源の放射特性のエンベロープが円形である場合 には、同じ円形のエンベロープの放射特性を有する仮想の光源を点 Fに形成するこ と力 Sできる。次に、この同じ円形のエンベロープの放射特性を有する発光源を用いて 、凸シリンダレンズの焦点距離 flを、凸レンズの焦点距離 fOよりも小さくすると、図 31 の（2)に示すように、光軸の方向において偏平な楕円状のエンベロープの放射特性 を有する仮想の光源を形成することができる。一方、 f l〉f0である場合には、図 31の (3)に示すように、光軸の方向において鋭い楕円状のエンベロープの放射特性を有 する仮想の光源を形成することができる。 （ただし、現実にはフードレンズのサイズや 臨界角の関係から図中の矢印の外側へ向かう光束は生じなレ、)。 [0276] Here, as shown in Fig. 31 (1), the light source LED is placed at the focal point of the convex lens (focal length fO) which is also a hood. In addition, a convex cylinder lens (focal length fl) having the same focal length as that of the convex lens is arranged on the front surface of the convex lens so that the optical axis of the convex lens coincides with the optical axis of the convex cylinder lens. At this time, a virtual light source having radiation characteristics similar to the radiation characteristics of the light emitting source can be formed at the focal position of the convex cylinder lens. For example, as shown in (1) of FIG. 28 (b), when the envelope of the emission characteristic of the light source is circular, a virtual light source having the same circular envelope emission characteristic is formed at the point F. And force S. Next, when the focal length fl of the convex cylinder lens is made smaller than the focal length fO of the convex lens by using the light source having the same circular envelope radiation characteristic, as shown in (2) of FIG. It is possible to form a virtual light source having a radiation characteristic of an elliptical envelope that is flat in the axial direction. On the other hand, when fl> f0, as shown in (3) of Fig. 31, there is a radiation characteristic of a sharp elliptical envelope in the direction of the optical axis. A virtual light source can be formed. (However, in reality, there is no luminous flux going outside the arrow in the figure due to the size of the hood lens and the critical angle.)
[0277] 図 30 (a)においては、凸レンズの形状及び凸シリンダレンズの形状の関係は、図 3 1の（1)、 （2)及び（3)のいずれかであり、凸レンズ及び凸シリンダレンズは、主走査 方向（Sx)に並べられる。図 30 (a)においては、個々の発光源 LEDから放出される 光の光束は、凸レンズである対応するフードレンズによって、平行光にされた後に、 凸シリンダレンズである照明レンズ (3)によって集光し、発散させられる。そして、本発 明の第 12の実施例においては、撮像領域 (Ai)の中心線側に配置された凸シリンダ レンズの焦点の位置 (仮想の光源の位置）よりも撮像領域 (Ai)の周辺側に配置され た凸シリンダレンズの焦点の位置 (仮想の光源の位置）が、撮像領域 (Ai)に近いよう に、光源 LED、凸レンズ、及び、凸シリンダレンズの組みを配置する。より具体的には 、撮像領域 (Ai)と凸シリンダレンズの焦点の位置 (仮想の光源の位置）との間の距離 は、一次元 CCDに結像レンズによって結像される画像の相対明度に比例し、前述の 式し X cos4 0によって与えられる。なお、図 30 (a)においては、光源の数は、 10個In FIG. 30 (a), the relationship between the shape of the convex lens and the shape of the convex cylinder lens is any one of (1), (2) and (3) in FIG. Are arranged in the main scanning direction (Sx). In FIG. 30 (a), the light flux emitted from each light emitting source LED is collimated by a corresponding hood lens that is a convex lens and then collected by an illumination lens (3) that is a convex cylinder lens. Light and diverge. In the twelfth embodiment of the present invention, the periphery of the imaging area (Ai) is more than the focal position (virtual light source position) of the convex cylinder lens disposed on the center line side of the imaging area (Ai). The pair of light source LED, convex lens, and convex cylinder lens is placed so that the focal position (imaginary light source position) of the convex cylinder lens placed on the side is close to the imaging area (Ai). More specifically, the distance between the imaging area (Ai) and the focal position of the convex cylinder lens (the position of the virtual light source) is the relative brightness of the image formed on the one-dimensional CCD by the imaging lens. Is proportional and given by X cos 40 . In FIG. 30 (a), the number of light sources is 10
0 0
で示してある力 S、シミュレーションでは、光源の数を 25個に設定した。  In the simulation with force S indicated by, the number of light sources was set to 25.
[0278] 図 30 (b)においては、主走査方向（Sx)における中央部及び一方の端部の光源、 凸レンズ、及び凸シリンダレンズの組みのみを記載しており、その他の光源、凸レンズ 、及び凸シリンダレンズを、省略している。図 30 (b)に示すように、副走査方向（Sy) においては、個々の発光源 LEDから放出された光の光束を、その LEDに対応する 凸レンズであるフードレンズによって、平行光にした後、凸シリンダレンズである照明 レンズ (3)を平行光として通過し、集束レンズ (4a) (又は集束ミラー）によって撮像領 域 (撮像対象領域）（Ai)に集束させる。主走査方向（Sx)における中央部分と周辺部 分との間で、撮像領域 (Ai)から光源までの距離は、変動するが、集束レンズ (4a) ( 又は集束ミラー）から撮像領域 (Ai)までの距離は、一定であるので、発光源 LEDか ら放出された光の集束の程度は、主走査方向（Sx)における光源の位置によっては 変動しない。言い換えれば、副走査方向（Sy)において、照明レンズ (3)から集束レ ンズ (4a) (又は集束ミラー）までの距離は、変動するが、光束は、照明レンズ (3)から 集束レンズ (4a) (又は集束ミラー）までの間では平行光である。また、光束が集束す る、集束レンズ (4a) (又は集束ミラー）から撮像領域 (Ai)までの距離が一定であるの で、光の集束の程度は、変動しない。なお、集束レンズ (4a) (又は集束ミラー）を、必 ずしも揷入する必要はない。すなわち、原稿の浮きを考慮する場合には、集束レンズ (4a) (又は集束ミラー）を用いないことが、好ましい。しかしながら、この場合において も、一次元 CCD上に結像される画像の相対明度を、一定にする目的を損ねることは ない。 In FIG. 30 (b), only the combination of the light source, the convex lens, and the convex cylinder lens at the center and one end in the main scanning direction (Sx) is shown, and the other light source, convex lens, and The convex cylinder lens is omitted. As shown in FIG. 30 (b), in the sub-scanning direction (Sy), the light flux emitted from each light emitting source LED is converted into parallel light by a hood lens that is a convex lens corresponding to the LED. Then, the light passes through the illumination lens (3), which is a convex cylinder lens, as parallel light and is focused on the imaging area (imaging target area) (Ai) by the focusing lens (4a) (or focusing mirror). The distance from the imaging area (Ai) to the light source varies between the central part and the peripheral part in the main scanning direction (Sx), but the distance from the focusing lens (4a) (or focusing mirror) to the imaging area (Ai) Since the distance to the light source is constant, the degree of focusing of the light emitted from the light emitting source LED does not vary depending on the position of the light source in the main scanning direction (Sx). In other words, in the sub-scanning direction (Sy), the distance from the illumination lens (3) to the focusing lens (4a) (or focusing mirror) fluctuates, but the luminous flux from the illumination lens (3) to the focusing lens (4a ) (Or focusing mirror) is parallel light. Also, the light beam is focused Since the distance from the focusing lens (4a) (or focusing mirror) to the imaging area (Ai) is constant, the degree of focusing of light does not vary. It is not always necessary to insert the focusing lens (4a) (or focusing mirror). That is, when taking into consideration the floating of the document, it is preferable not to use the focusing lens (4a) (or the focusing mirror). However, even in this case, the purpose of making the relative brightness of the image formed on the one-dimensional CCD constant is not impaired.
実施例 13  Example 13
[0279] 本発明の第 13の実施例は、複数の光源から放出される光の放射特性を調整して 撮像対象領域 (Ai)を照明する光の照度分布を 1/cos4 Θの特性に一致させる例を 示す。 [0279] In the thirteenth embodiment of the present invention, the illuminance distribution of light that illuminates the imaging target area (Ai) is adjusted to 1 / cos 4 Θ by adjusting the radiation characteristics of the light emitted from the plurality of light sources. An example of matching is shown.
[0280] 図 32は、一次元 CCDに結像される画像の相対明度が一定となるような、撮像対象 領域を照明する複数の光源の具体的な配置を説明する図である。図 32 (a)は、複数 の光源の配置及び側面鏡を配置する鏡面の位置を示す図であり、図 32 (b)は、光源 の放射特性の例を示す図である。  FIG. 32 is a diagram for explaining a specific arrangement of a plurality of light sources that illuminate the imaging target region so that the relative brightness of the image formed on the one-dimensional CCD is constant. FIG. 32 (a) is a diagram showing the arrangement of a plurality of light sources and the position of the mirror surface on which the side mirror is arranged, and FIG. 32 (b) is a diagram showing an example of the radiation characteristics of the light sources.
[0281] 図 32における記号は、図 24における記号と同一である力 主走査方向（Sx)にお ける複数の光源の間隔及び複数の光源の各々から照明対象領域 (撮像対象領域）（ Ai)までの距離は、一定である。即ち、図 32 (a)においては、複数の光源の間隔 wl , w2 , •••wnii,一定であり、 Wh/Nに等しい。言い換えれば、複数の光源の間隔 wl , w2, •••wntt,主走査方向（Sx)における撮像対象領域 (Ai)の長さの半分 Whを N 等分することによって与えられる。また、複数の光源の各々から照明対象領域 (撮像 対象領域）（Ai)までの距離は、 Lである。し力もながら、それぞれの光源から放出さ  The symbols in FIG. 32 are the same as the symbols in FIG. 24. The distance between the light sources in the main scanning direction (Sx) and the illumination target area (imaging target area) (Ai) The distance to is constant. That is, in FIG. 32 (a), the intervals wl, w2, ••• wnii of the plurality of light sources are constant and equal to Wh / N. In other words, the intervals wl, w2, ••• wntt of the plurality of light sources are given by dividing the half Wh of the length of the imaging target area (Ai) in the main scanning direction (Sx) into N equal parts. The distance from each of the plurality of light sources to the illumination target area (imaging target area) (Ai) is L. However, it is emitted from each light source.
0  0
れる光の放射特性は変化させてレ、る。  The light radiation characteristics are changed.
[0282] その変化のさせ方を説明する。即ち、光源が発する総光量は同じとして、照度を落 とす領域では発光光束をより分散させ、照度を上げる領域では発光光束をあまり分 散させないようにするのである。その光束の分散の程度を放射特性式 cosa aで近似 できる力 その代表を図あるいは式で表すと、図 32 (b)に示すように積極的に分散さ せる場合は図 32 ( l ) a = l (cos0' 5 a )のように、分散の程度を抑える場合は図 32 (3) a = 2 (cos2 α )のようになる。図 32 (2) a = 1 (cos α )はその中間である。ここで重要な ことは光源から放出される総光量が一定ならば、光の放射ベクトルのエンベロープで 囲まれた面積は aが変化しても一定であることである。 [0282] How to make the change will be described. In other words, the total amount of light emitted from the light source is the same, and the luminous flux is more dispersed in the area where the illuminance is reduced, and the luminous flux is less scattered in the area where the illuminance is increased. The force that can approximate the degree of dispersion of the luminous flux by the radiation characteristic equation cos a a The representative example is shown in the figure or formula. When actively dispersing as shown in Fig. 32 (b), Fig. 32 (l) a When the degree of dispersion is suppressed as shown in = l (cos 0 ' 5 a), it becomes as shown in Fig. 32 (3) a = 2 (cos 2 α). Figure 32 (2) a = 1 (cos α) is in the middle. Important here This means that if the total amount of light emitted from the light source is constant, the area enclosed by the envelope of the light radiation vector is constant even if a changes.
[0283] ここで、撮像対象領域 (Ai)の任意の分割点 (複数の光源のうち k番目の位置 Pに [0283] Here, an arbitrary division point of the imaging target area (Ai) (at the kth position P of the plurality of light sources)
k 対応する分割点）での目標照度の相対値を改めて Tkとする。即ち目標値 Tkを、コサ イン四乗則に従って、改めて  Let the relative value of the target illuminance at the corresponding division point) be Tk again. In other words, the target value Tk is renewed according to the Cosine fourth law
[0284] [数 21] cos 6k [0284] [Equation 21] cos 6 k
[0285] とする。ここで、 Θ は、結像レンズの光軸に対する、結像レンズの中心と撮像対象領 [0285] Where Θ is the center of the imaging lens and the area to be imaged with respect to the optical axis of the imaging lens.
k  k
域 (Ai)上の k番目の分割点とを結ぶ直線の角度である。また、複数の光源のうち k番 目の位置 Pに配置される光源から放出される光の放射特性を、式  The angle of the straight line connecting the kth division point on the area (Ai). In addition, the radiation characteristics of the light emitted from the light source arranged at the kth position P among the plurality of light sources are
k  k
[0286] [数 22]  [0286] [Equation 22]
Rk = Tk 2 - cosB(k) ak R k = T k 2 -cos B (k) a k
[0287] に従って、設定する。なお、式中、 T 2は、 k番目の位置 Pにある光源から放出される Set according to [0287]. Where T 2 is emitted from the light source at the kth position P.
k k  k k
光の放射ベクトルのうち、照明対象面（撮像領域）（Ai)に対して鉛直方向のベクトノレ の強度であり、 B (k)は、 k番目の位置 Pにある光源から放出される光の放射べクトノレ  Among the light emission vectors, the intensity of the vector vector in the vertical direction with respect to the illumination target surface (imaging area) (Ai), and B (k) is the light emission emitted from the light source at the kth position P. Vectnore
k  k
の放射特性 (エンベロープ）の形状を規定する関数であり、 B (k) =a-T bで表される Is a function that defines the shape of the radiation characteristic (envelope) of B, expressed as B (k) = aT b
k  k
。ここで、 aは初期値 (放射特性の形状の初期値)であり、 bは形状係数 (その形状の 変化の程度を規定するパラメータ）である。すなわち、 k = 0に対して、位置 Pにある  . Here, a is an initial value (initial value of the shape of the radiation characteristic), and b is a shape factor (a parameter that defines the degree of change of the shape). That is, at position P for k = 0
0 光源から放出される光の放射特性の形状は B (k = 0) =aであり、図 32 (b)に示すよう に、 aのみによって一意に決定される。  0 The shape of the radiation characteristic of light emitted from the light source is B (k = 0) = a, and is uniquely determined only by a as shown in Fig. 32 (b).
[0288] よって、複数の光源から放出される光によって照射される撮像対象領域 (Ai)にお ける任意の点 Mmでの相対照度 I (Mm)は、本発明の第 12の実施例と同様の考え 方で、式 [0288] Therefore, the relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) irradiated with light emitted from a plurality of light sources is the same as in the twelfth embodiment of the present invention. In the way of thinking
[0289] [数 23] [0289] [Equation 23]
I(Mm) = > Ak -cos2 ak - Tk ^ cosB k) ak こたし、 < ak≤―) [0290] によって表される。 I (Mm) => A k -cos 2 a k -T k ^ cos B k) a k , <a k ≤―) [0290]
[0291] この式を用い、 N= 12、 a = 0. 5、 b = 3. 1として、本発明の第 11の実施例と同様 の方法で、複数の光源によって照明される撮像対象領域 (Ai)の全域にわたる照度 分布を求めた結果、図 26と同様のグラフを得ることができた。そのうち、 W : Ld= l : l の条件の下で行ったシミュレーションの結果による照度分布と目標の照度分布との差  [0291] Using this equation, N = 12, a = 0.5, b = 3.1, and in the same manner as in the eleventh embodiment of the present invention, an imaging target region illuminated by a plurality of light sources ( As a result of obtaining the illuminance distribution over the entire area of Ai), the same graph as in Fig. 26 was obtained. Of these, the difference between the illuminance distribution and the target illuminance distribution as a result of simulation under the condition of W: Ld = l: l
[0292] 図 29中の（2)の曲線の両端付近が乱れて目標照度との差分が多く発生している理 由は、実施例 12の理由と似たような理由で、位置 P 力も位置 P までの光源が、 [0292] The reason why both ends of the curve (2) in Fig. 29 are disturbed and the difference from the target illuminance is large is similar to the reason of Example 12, and the position P force is also the position. Light sources up to P
n+ 1 2n+ l  n + 1 2n + l
位置 P力 位置 Pまでの光源の鏡像である虚光源であるので、光源の光の放射特 Position P force Because it is a virtual light source that is a mirror image of the light source up to position P, the light emission characteristics of the light source
0 n 0 n
性を理想的な特性にしてレヽなレ、ためである。ただし、位置 Pと位置 P の間における 側面鏡の位置を若干 P側に接近させたり、側面鏡の角度を微妙に変化させたり、適 切に設定することによって、撮像対象領域 (Ai)の両端付近における照度分布をある 程度制卸すること力でさる。  This is because it has a characteristic that makes it ideal. However, if the position of the side mirror between position P and position P is slightly closer to the P side, or the angle of the side mirror is slightly changed, or set appropriately, both ends of the imaging target area (Ai) It is the power to control the illuminance distribution in the vicinity to some extent.
[0293] しかしながら、このままでも、その差分の最大値は、 ± 5%程度であり、図 29のダラ フ（1)に示される差分の最大値よりも若干大きくなる。し力、しながら、このような差分の 最大値は、部品の精度や組み立ての精度の観点及び省エネルギーの観点のレ、ずれ 力、らも殆ど問題とならな!/、。 （一次元 CCDで光量を電気信号に変換した後の電気信 号の増幅率を変えてその差分を補正しても、その増幅率の変更は小さぐノイズの影 響を受けることはほとんどない。 )  [0293] However, even if it remains as it is, the maximum value of the difference is about ± 5%, which is slightly larger than the maximum value of the difference shown in the drawing (1) in FIG. However, the maximum value of such a difference is almost a problem with regard to the accuracy of parts and assembly, as well as the power and displacement from the viewpoint of energy saving! /. (Even if you change the amplification factor of the electrical signal after converting the light quantity into an electrical signal with a one-dimensional CCD and correct the difference, the change in the amplification factor is hardly affected by the small noise. )
次に、以上説明した複数の光源から放出される光の放射特性を調整することによつ て、撮像対象領域 (Ai)を照明する光の照度分布を 1/cos4 Θの特性に一致させる 照明装置を実現するための概念を示す。 Next, by adjusting the radiation characteristics of the light emitted from the multiple light sources described above, the illuminance distribution of the light that illuminates the imaging target area (Ai) is matched with the 1 / cos 4 Θ characteristics. A concept for realizing a lighting device will be described.
[0294] 図 33は、複数の光源から放出される光の放射特性を調整することによって、撮像領 域 (撮像対象領域)を照明する光の照度分布を 1/cos4 Θの特性に一致させる照明 装置を実現するための概念図である。図 33 (a)は、その上面図であり、図 33 (b)は、 その正面図である。 [0294] Figure 33 shows that the illuminance distribution of the light that illuminates the imaging area (imaging target area) matches the 1 / cos 4 Θ characteristics by adjusting the radiation characteristics of the light emitted from multiple light sources. It is a conceptual diagram for implement | achieving an illuminating device. FIG. 33 (a) is a top view thereof, and FIG. 33 (b) is a front view thereof.
[0295] 図 33 (a)に示す図においては、主走査方向（Sx)に配置される複数の光源に対応 する凸レンズの焦点距離は、一定であり、主走査方向（Sx)に配置された複数の光源 に対応する照明レンズ (凸シリンダレンズ）（3)の焦点距離は、図 31に示すようにして 、変化する。図 33 (a)に示す照明装置の中央付近では、照明レンズの焦点位置に形 成される仮想の光源の放射特性のエンベロープが、図 31の（2)に示すように、分散 が強い偏平の楕円状になるように、相対的に短い焦点距離の照明レンズを用い、周 辺に向かってその偏平度を少なくするように焦点距離を徐々に長くしていき、途中、 図 33 (1)のような円形に近いエンベロープとする照明レンズを用いるのを経て、その 後は図 31の（3)に示すように、分散の少ない鋭い楕円状になるように、相対的に長 V、焦点距離の照明レンズを用 V、る。 In the diagram shown in FIG. 33 (a), the focal lengths of the convex lenses corresponding to the plurality of light sources arranged in the main scanning direction (Sx) are constant and arranged in the main scanning direction (Sx). Multiple light sources The focal length of the illumination lens (convex cylinder lens) (3) corresponding to is changed as shown in FIG. In the vicinity of the center of the illumination device shown in Fig. 33 (a), the envelope of the radiation characteristic of the virtual light source formed at the focal position of the illumination lens is flat with strong dispersion as shown in Fig. 31 (2). Use an illumination lens with a relatively short focal length so that it has an elliptical shape, and gradually increase the focal length to reduce its flatness toward the periphery. After using an illumination lens with a nearly circular envelope like this, after that, as shown in Fig. 31 (3), a relatively long V, focal length is obtained so that it becomes a sharp ellipse with little dispersion. Use an illumination lens.
[0296] 即ち、照明レンズの焦点位置に形成される仮想の光源の放射特性の楕円状のェン ベロープの形状は、前述の式 R =T 2-cosB(k) a に従って変化させている。 That is, the shape of the elliptic envelope of the emission characteristic of the virtual light source formed at the focal position of the illumination lens is changed according to the above-described equation R = T 2 -cos B (k) a .
k k k  k k k
[0297] また、照明レンズの焦点位置に形成される仮想の光源の放射特性の楕円状のェン ベロープの形状が変動するように、照明レンズの焦点距離を変化させることによって 、発光源から仮想光源までの距離も、照明装置の中央付近と周辺付近との間で変動 する。それゆえ、仮想光源から照明対象面 (撮像領域）（Ai)までの距離を一定にす るために、発光源 LEDの位置を、照明装置の中央付近と周辺付近との間で、変動さ せている。なお、シミュレーションでは、光源の数を 25個にした力 図 33 (a)において は、光源の数を 10個で示してある。  [0297] Further, by changing the focal length of the illumination lens so that the shape of the elliptical envelope of the emission characteristic of the virtual light source formed at the focal position of the illumination lens varies, The distance to the light source also varies between the vicinity of the center of the lighting device and the vicinity. Therefore, in order to make the distance from the virtual light source to the illumination target surface (imaging area) (Ai) constant, the position of the light source LED is varied between the vicinity of the center of the illumination device and the vicinity of the periphery. ing. In the simulation, the force with 25 light sources is shown in Fig. 33 (a), where the number of light sources is 10.
[0298] 図 33 (b)においては、主走査方向（Sx)における中央部及び一方の端部の光源、 凸レンズ、及び凸シリンダレンズの組みのみを記載しており、その他の光源、凸レンズ 、及び凸シリンダレンズを、省略している。図 33 (b)に示すように、副走査方向（Sy) においては、個々の発光源 LEDから放出された光の光束を、その LEDに対応する 凸レンズであるフードレンズによって、平行光にした後、凸シリンダレンズである照明 レンズ (3)を平行光として通過し、集束レンズ (4a) (又は集束ミラー）によって撮像領 域 (Ai)に集束させる。主走査方向（Sx)における中央部分と周辺部分との間で、撮 像領域 (Ai)から光源までの距離は、変動するが、集束レンズ (4a) (又は集束ミラー） 力、ら撮像領域 (Ai)までの距離は、一定であるので、発光源 LEDから放出された光の 集束の程度は、主走査方向（Sx)における光源の位置によっては変動しない。言い 換えれば、副走査方向（Sy)において、照明レンズから集束レンズ (4a) (又は集束ミ ラー）までの距離は、変動するが、光束は、照明レンズから集束レンズ (4a) (又は集 束ミラー）までの間では平行光である。また、光束が集束する、集束レンズ (4a) (又は 集束ミラー）から撮像領域 (Ai)までの距離が一定であるので、光の集束の程度は、 変動しない。なお、集束レンズ (4a) (又は集束ミラー）を、必ずしも揷入する必要はな い。すなわち、原稿の浮きを考慮する場合には、集束レンズ (4a) (又は集束ミラー）を 用いないことが、好ましい。し力もながら、この場合においても、一次元 CCD上に結 像される画像の明度を、一定にする目的を損ねることはなレ、。 In FIG. 33 (b), only the combination of the light source, the convex lens, and the convex cylinder lens at the center and one end in the main scanning direction (Sx) is shown, and the other light source, convex lens, and The convex cylinder lens is omitted. As shown in FIG. 33 (b), in the sub-scanning direction (Sy), the light flux emitted from each light emitting source LED is converted into parallel light by a hood lens that is a convex lens corresponding to the LED. Then, the light passes through the illumination lens (3), which is a convex cylinder lens, as parallel light, and is focused on the imaging area (Ai) by the focusing lens (4a) (or focusing mirror). Although the distance from the imaging area (Ai) to the light source varies between the central part and the peripheral part in the main scanning direction (Sx), the focusing lens (4a) (or focusing mirror) force and imaging area ( Since the distance to Ai) is constant, the degree of focusing of the light emitted from the light source LED does not vary depending on the position of the light source in the main scanning direction (Sx). In other words, from the illumination lens to the focusing lens (4a) (or focusing mirror) in the sub-scanning direction (Sy). The distance from the illumination lens to the focusing lens (4a) (or the collecting mirror) is parallel light. In addition, since the distance from the focusing lens (4a) (or focusing mirror) to the imaging area (Ai) where the light beam is focused is constant, the degree of focusing of the light does not change. Note that it is not always necessary to insert the focusing lens (4a) (or the focusing mirror). That is, when taking into account the floating of the document, it is preferable not to use the focusing lens (4a) (or the focusing mirror). However, even in this case, the purpose of making the brightness of the image formed on the one-dimensional CCD constant is not impaired.
なお、以上述べた図 33に示す概念を装置化して第 1走行体に搭載する方法は、前 述の実施例 11の方法に準じており、当業者には容易に実施可能である。  Note that the method of embodying the concept shown in FIG. 33 and mounting it on the first traveling body is in accordance with the method of Example 11 described above, and can be easily implemented by those skilled in the art.
実施例 14  Example 14
[0299] 本発明の第 14の実施例は、撮像領域 (撮像対象領域）（Ai)を照明する光の照度 分布を 1 /cos4 Θの特性に近似する照明装置の概念の一例を示す。 The fourteenth embodiment of the present invention shows an example of a concept of an illuminating device that approximates the illuminance distribution of light that illuminates the imaging region (imaging target region) (Ai) to the characteristic of 1 / cos 4 Θ.
[0300] 図 34は、複数の光源の各々力も撮像領域 (Ai)までの距離を調整することによって[0300] Figure 34 shows that each force of multiple light sources is adjusted by adjusting the distance to the imaging area (Ai).
、撮像領域 (Ai)を照明する光の照度分布を i/cos 4 eの特性に近似する照明装置 を実現するための概念図である。図 34 (a)は、その上面図であり、図 34 (b)は、その 正面図である。図 34 (c)は、 l/cos4 6の特性に近似された撮像領域を照明する光 の照度分布の例を示す図である。 FIG. 5 is a conceptual diagram for realizing an illumination device that approximates the illuminance distribution of light that illuminates the imaging region (Ai) to the i / cos 4 e characteristic. FIG. 34 (a) is a top view thereof, and FIG. 34 (b) is a front view thereof. FIG. 34 (c) is a diagram showing an example of the illuminance distribution of the light illuminating the imaging area which is approximated to the characteristic of l / cos 4 6.
[0301] 本発明の第 12の実施例において、複数の光源の各々から撮像領域 (Ai)までの距 離を調整することによって、撮像領域 (Ai)を照明する光の照度分布を 1/cos4 Θの 特性により良好な精度で一致する照明装置の例を説明してきた。 1/cos4 Θの特性 を有するべきである撮像領域 (Ai)を照明する光の照度分布の精度を多少犠牲にす ることによって、例えば、より容易に製造することが可能な構成を考えることができる。 図 34に示す本発明の実施例による照明装置は、本発明の第 12の実施例に説明し た照明装置よりもより容易に製造することが可能なものである。 [0301] In the twelfth embodiment of the present invention, by adjusting the distance from each of the plurality of light sources to the imaging region (Ai), the illuminance distribution of the light that illuminates the imaging region (Ai) is 1 / cos. the characteristics of the 4 theta has been described an example of a lighting device matching with good accuracy. Consider a configuration that can be manufactured more easily, for example, by sacrificing the accuracy of the illuminance distribution of the light that illuminates the imaging area (Ai), which should have the characteristic of 1 / cos 4 Θ. Can do. The illumination device according to the embodiment of the present invention shown in FIG. 34 can be more easily manufactured than the illumination device described in the twelfth embodiment of the present invention.
[0302] まず、図 34 (c)に示すように、本発明の第 12の実施例における 1/cos4 Θの特性 を有する撮像領域 (Ai)での理想的な照度分布を与える、複数の光源の相対的な位 置 L /L =cos4 6の曲線を、撮像領域 (Ai)の範囲で三分割（3Dev)する。そして、 k 0 First, as shown in FIG. 34 (c), a plurality of illuminance distributions giving an ideal illuminance distribution in the imaging region (Ai) having the characteristic of 1 / cos 4 Θ in the twelfth embodiment of the present invention. the relative position L / L = cos 4 6 curves of the light source, is divided into three parts (3Dev) in range of the imaging area (Ai). And k 0
その曲線を三分割した位置における曲線上の点（Pb, Pc)を頂点とする台形 (Pa— P b— Pc— Pd)に近似する。そして、その台形（に合同な台形）の各辺（Pa— Pb、 Pb— Pc、 Pc— Pd)上に光源を配置する力、、又は、その台形（に合同な台形）の各辺（Pa Pb、 Pb— Pc、 Pc— Pd)上に仮想光源が位置するように光源を配置する。なお、複 数の光源の相対的な位置を示す cos4 Θの曲線を台形に近似した場合、理想的な照 度分布と近似の構成の照度分布との差異は、複数の光源の理想的な cos4 Θの曲線 上の位置と複数の光源の台形の辺上の位置との差異に基づくものにすぎず、非常に 小さい。 A trapezoid (Pa— P) with the point (Pb, Pc) on the curve at the position where the curve is divided into three. b—Pc—Pd). And the force to place the light source on each side (Pa-Pb, Pb-Pc, Pc-Pd) of the trapezoid (congruent trapezoid), or each side (Pa The light sources are arranged so that the virtual light source is positioned on (Pb, Pb—Pc, Pc—Pd). When the cos 4 Θ curve indicating the relative position of multiple light sources is approximated to a trapezoid, the difference between the ideal illumination distribution and the approximate illuminance distribution is the ideal cos 4 It is based on the difference between the position on the curve of Θ and the position on the side of the trapezoid of multiple light sources, and is very small.
[0303] 図 34 (a)は、複数の光源の各々力も撮像領域 (Ai)までの距離を調整することによ つて、撮像領域 (Ai)を照明する光の目標の照度分布を台形の特性で近似させる照 明装置の概念を示す。図 34 (a)に示すように、例えば、台形の特性において撮像領 域 (Ai)に対して平行な台形の辺の特性を与える光源は、光源又は仮想光源 (ここで は、照明レンズ (3)の焦点）を、撮像領域 (Ai)に対して平行な台形の辺の上に位置 するように、配置する。また、例えば、台形の特性において撮像領域 (Ai)に対して傾 斜する辺の特性を与える光源は、光源又は仮想光源 (ここでは、照明レンズ（3)の焦 点）が、撮像領域 (Ai)に対して傾斜する辺と平行に位置するように配置され、シリン ダレンズである照明レンズ (3)の撮像領域 (Ai)側にプリズム（7)を設ける。照明レン ズ（3)よりも撮像領域 (Ai)側に設けられたプリズム（7)によって、光源又は仮想光源 から延びる光軸がプリズム（7)で折り曲げられ、折り曲げられた光軸が、撮像領域 (Ai )に対して鉛直になるようにする。  [0303] Figure 34 (a) shows the trapezoidal characteristics of the target illuminance distribution of the light that illuminates the imaging area (Ai) by adjusting the distance to the imaging area (Ai) for each of the light sources. The concept of the lighting device approximated by is shown. As shown in Fig. 34 (a), for example, the light source that gives the trapezoidal side characteristic parallel to the imaging area (Ai) in the trapezoidal characteristic is a light source or a virtual light source (here, an illumination lens (3 ) Is placed on a trapezoidal side parallel to the imaging area (Ai). Further, for example, a light source that gives a characteristic of a side inclined with respect to the imaging region (Ai) in the trapezoidal characteristic is a light source or a virtual light source (here, the focal point of the illumination lens (3)), and the imaging region (Ai The prism (7) is provided on the imaging region (Ai) side of the illumination lens (3) that is a cylinder lens. The optical axis extending from the light source or the virtual light source is bent by the prism (7) by the prism (7) provided closer to the imaging area (Ai) than the illumination lens (3), and the bent optical axis becomes the imaging area. Be perpendicular to (Ai).
[0304] 図 34に示すような構成を採用することによって、光源を支持する基板として、平面 板を用いることができ、照明装置の製造が、より容易になる。  [0304] By adopting the configuration as shown in FIG. 34, a flat plate can be used as the substrate for supporting the light source, which makes it easier to manufacture the lighting device.
[0305] 図 34 (a)及び (b)においては、発光源 LEDから放出される光束を平行光にするた めに回転放物面鏡を用いている力 S、砲弾型のフードレンズを用いてもよい。さらに、 少し効率を犠牲にして図 34においては、 l/cos4 eの特性を有する撮像領域 (Ai) での理想的な照度分布を与える、複数の光源の相対的な位置の曲線 cos4 Θを、撮 像領域 (Ai)の範囲で三分割したが、更に効率を犠牲にして良!/、ならば撮像領域 (Ai )の範囲で二分割してもよい。そして、複数の光源の相対的な位置の曲線を、その曲 線を二分割した位置における曲線上の点を頂点とする三角形に近似してもよい。こ の場合には、複数の光源は、撮像領域 (Ai)に対して傾斜する辺にのみ配置されるこ とになる。このように、撮像領域 (Ai)の範囲で二分割して複数の光源の相対的な位 置の曲線を三角形に近似したとしても、撮像領域 (Ai)を均一に照明する場合と比較 して、光源から放出される光の利用効率を大幅に向上させることができる。 [0305] In Fig. 34 (a) and (b), a force S using a paraboloidal mirror is used to make the luminous flux emitted from the light source LED parallel light, and a shell-shaped hood lens is used. May be. In addition, at the expense of a little efficiency, in Figure 34, the relative position curve of multiple light sources, cos 4 Θ, gives an ideal illumination distribution in the imaging area (Ai) with l / cos 4 e characteristics. Is divided into three in the range of the imaging region (Ai), but may be divided into two in the range of the imaging region (Ai) if the efficiency is sacrificed. Then, the curve of the relative position of the plurality of light sources may be approximated to a triangle whose vertex is a point on the curve at a position where the curve is divided into two. This In this case, the plurality of light sources are arranged only on the side inclined with respect to the imaging area (Ai). In this way, even if the relative position curve of the multiple light sources is approximated to a triangle by dividing into two in the range of the imaging area (Ai), compared with the case where the imaging area (Ai) is illuminated uniformly. The use efficiency of light emitted from the light source can be greatly improved.
[0306] 同様に、本発明の第 13の実施例においても、 1/cos4 Θの特性を有する撮像領域 Similarly, in the thirteenth embodiment of the present invention, the imaging region having the characteristic of 1 / cos 4 Θ
(Ai)での理想的な照度分布を与える、複数の光源の相対的な位置の曲線を、撮像 領域 (Ai)の範囲で多角形に近似することが可能である。例えば、本発明の第 13の 実施例における 1/cos4 Θの特性を有する撮像領域 (Ai)での理想的な照度分布を 与える、複数の光源の相対的な位置の曲線を、本発明の第 12の実施例における近 似の台形又は三角形の頂点の位置と撮像領域 (Ai)に平行な面に対して反対側の 位置に頂点を有する台形又は三角形に近似してもよい。この場合には、光源を支持 する基板として、平面板を用いることができ、照明装置の製造が、より容易となる。 It is possible to approximate the curve of the relative positions of multiple light sources that give the ideal illuminance distribution in (Ai) to a polygon within the range of the imaging area (Ai). For example, in the thirteenth embodiment of the present invention, a curve of the relative positions of a plurality of light sources that gives an ideal illuminance distribution in the imaging region (Ai) having the characteristic of 1 / cos 4 Θ The approximate trapezoidal or triangular vertex position in the twelfth embodiment may be approximated to a trapezoidal or triangular shape having a vertex at a position opposite to the plane parallel to the imaging area (Ai). In this case, a flat plate can be used as the substrate for supporting the light source, and the manufacture of the lighting device becomes easier.
[0307] 加えて、図 34に示す照明装置において、発光源が、赤色 (R)、緑色（G)、及び青 色（B)の LEDの組み合わせである場合、プリズムによる赤色光、緑色光、青色光の 間に色収差が生じる。し力、しながら、複数のプリズムを通過した赤色光、緑色光、及 び青色光は、撮像領域 (Ai)で互いに重畳し、ほぼ白色光の照明を撮像領域 (Ai)に 提供することになる。従って、実際上、プリズムによる色収差が問題になることは少な い。  In addition, in the lighting device shown in FIG. 34, when the light source is a combination of red (R), green (G), and blue (B) LEDs, red light, green light, Chromatic aberration occurs between blue light. However, the red light, the green light, and the blue light that have passed through the plurality of prisms are superimposed on each other in the imaging region (Ai) to provide almost white light illumination to the imaging region (Ai). Become. Therefore, in practice, chromatic aberration due to the prism is rarely a problem.
[0308] なお、従来技術におけるほぼ一定の照度分布となっている撮像領域 (Ai)の中央部 分の光束を捨てるということは、図 34 (c)に示す多くの光量 (ハッチングの部分の光 量)を捨てることになる。これに対して、本発明の第 14の実施例によれば、 目標位置 の曲線と台形の近似折れ線とで挟まれた部分のわずかな光量のみを捨てるだけであ る。それゆえ、本発明の第 14の実施例によれば、光量に対応する電気信号の電気 的な補正は、わずかであり、電気信号に対するノイズの影響も従来技術よりも低減で きる。  [0308] Note that discarding the light flux in the center of the imaging area (Ai), which has an almost constant illuminance distribution in the prior art, means that a large amount of light (hatched light) is shown in Fig. 34 (c). Amount). On the other hand, according to the fourteenth embodiment of the present invention, only a small amount of light in the portion sandwiched between the target position curve and the trapezoidal approximate polygonal line is discarded. Therefore, according to the fourteenth embodiment of the present invention, the electrical correction of the electrical signal corresponding to the light amount is slight, and the influence of noise on the electrical signal can be reduced as compared with the prior art.
なお、以上述べた図 34に示す概念を装置化して第 1走行体に搭載する方法も、前 述の実施例 11の方法に準じており、当業者には容易に実施可能である。  Note that the method of embodying the concept shown in FIG. 34 and mounting it on the first traveling body is also in accordance with the method of Example 11 described above, and can be easily implemented by those skilled in the art.
実施例 15 [0309] 本発明の第 15の実施例は、複数の光源の各々から撮像領域 (Ai)までの距離の調 整及び複数の光源から放出される光の放射特性の調整の両方によって、撮像領域 を照明する光の照度分布を 1/cos4 Θの特性に一致させる例を示す。 Example 15 [0309] In the fifteenth embodiment of the present invention, the imaging region is adjusted both by adjusting the distance from each of the plurality of light sources to the imaging region (Ai) and by adjusting the radiation characteristics of the light emitted from the plurality of light sources. An example of matching the illuminance distribution of the light illuminating with the 1 / cos 4 Θ characteristic is shown.
[0310] 図 35は、一次元 CCDに結像される画像の相対明度が一定となるような、撮像対象 領域 (Ai)を照明する複数の光源の具体的な配置を説明する図である。図 35 (a)は、 複数の光源の配置及び側面鏡を配置する鏡面の位置を示す図であり、図 35 (b)は、 光源の放射特性の例を示す図である。  FIG. 35 is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate the imaging target area (Ai) so that the relative brightness of an image formed on the one-dimensional CCD is constant. FIG. 35 (a) is a diagram showing the arrangement of a plurality of light sources and the position of the mirror surface on which the side mirror is arranged, and FIG. 35 (b) is a diagram showing an example of the radiation characteristics of the light sources.
[0311] 図 35 (a)に示す図においては、主走査方向（Sx)における複数の光源の間隔は、 一定であるが、複数の光源の各々から照明対象領域 (撮像対象領域）（Ai)までの距 離及び複数の光源から放出される光の放射特性を変化させる。図 35における記号 の意味は、図 24における記号と同一であり、複数の光源の間隔 wl , w2, · ' · ηは、 一定で、 Wh/Nに等しい。言い換えれば、複数の光源の間隔 wl , w2,•••wnii,主 走査方向（Sx)における撮像対象領域 (Ai)の長さの半分 Whを N等分することによつ て与えられる。  In the diagram shown in FIG. 35 (a), the intervals between the plurality of light sources in the main scanning direction (Sx) are constant, but the illumination target region (imaging target region) (Ai) from each of the plurality of light sources And the radiation characteristics of light emitted from multiple light sources. The meaning of the symbol in FIG. 35 is the same as the symbol in FIG. 24, and the intervals wl, w2, ··· η between the light sources are constant and equal to Wh / N. In other words, the intervals wl, w2, •• wnii of a plurality of light sources are given by dividing the half Wh of the length of the imaging target area (Ai) in the main scanning direction (Sx) into N equal parts.
[0312] 図 35 (a)に示す図においては、撮像対象領域 (Ai)から k番目の光源の位置 Pまで  [0312] In the diagram shown in Fig. 35 (a), from the imaging target area (Ai) to the position P of the kth light source.
k の距離 L' は、本発明の第 12の実施例中、式 L =L X cos4 6 で得られる値 Lと撮 The distance L ′ of k is taken as the value L obtained by the equation L = LX cos 4 6 in the twelfth embodiment of the present invention.
k k k k 像対象領域 (Ai)の中心線上に設けられた光源の位置 Pから照明対象面 (撮像領域  k k k k From the position P of the light source provided on the center line of the image target area (Ai) to the illumination target surface (imaging area
0  0
(Ai) )までの距離 Lとの間の中間的な距離である。即ち、撮像対象領域 (Ai)から k  (Ai) This is an intermediate distance between the distance L to). That is, from the imaging target area (Ai) to k
0  0
番目の光源の位置 Pまでの距離 L' は、  The distance L 'to the position P of the second light source is
k k  k k
[0313] [数 24]  [0313] [Equation 24]
L = 。 x cos Θ L =. x cos Θ
[0314] によって得られる距離となる。 （ここで、 Θ は、結像レンズの光軸に対する、結像レン k [0314] This is the distance obtained. (Where Θ is the imaging lens k with respect to the optical axis of the imaging lens.
ズの中心と撮像対象領域 (Ai)上の k番目の分割点とを結ぶ直線の角度である。 ) また、個々の光源が発する総光量は同じとして、照度を落とす領域では発光光束を より分散させ、照度を上げる領域では発光光束をあまり分散させないように光源から 放出される光の放射特性（光源から放出される光の放射ベクトルの角度に対する放 射ベクトルの強度）を変化させる。その変化の程度は、本発明の第 13の実施例にお ける変化の程度の半分である。すなわち、 [0315] [数 25] The angle of a straight line connecting the center of the image and the kth division point on the imaging target area (Ai). ) Also, assuming that the total amount of light emitted by each light source is the same, the emission characteristics (light source) The intensity of the radiation vector with respect to the angle of the radiation vector of the light emitted from is changed. The degree of the change is half that of the change in the thirteenth embodiment of the present invention. That is, [0315] [Equation 25]
[0316] であり、式中の B (k)の形状係数 bは、本発明の第 13の実施例における bの値の半分 である。 [0316] The shape factor b of B (k) in the equation is half the value of b in the thirteenth embodiment of the present invention.
[0317] このような条件の下で、複数の光源から放出される光によって照射される撮像対象 領域 (Ai)における任意の点 Mmでの相対照度 I (Mm)は、本発明の第 12の実施例 と同様の考え方で、式  [0317] Under such conditions, the relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) irradiated by the light emitted from the plurality of light sources is the twelfth aspect of the present invention. In the same way as in the example, the formula
[0318] [数 26]  [0318] [Equation 26]
I(Mm) - (10 IL f - cos2 ak - Tk - cosB k) ak (ただし、 ak≤^ I (Mm)-(1 0 IL f-cos 2 a k -T k -cos B k) a k (where a k ≤ ^
[0319] によって表される。 [0319]
[0320] この式を用いて、本発明の第 1 1の実施例と同様の方法で、複数の光源によって照 明される撮像対象領域 (Ai)の全域にわたる照度分布を求めた。 N = 12、 a = 0. 5、 b = l . 55の条件の下でのシミュレーションの結果、図 26と同様のグラフを得ることが できた。また、 W : Ld = l： 1の条件の下で行った、複数の光源によって照明される撮 像対象領域 (Ai)の全域にわたる照度分布のシミュレーションの結果による照度分布 と目標の照度分布との差分は、図 29のグラフ（3)のようなものであった。  [0320] Using this equation, the illuminance distribution over the entire region to be imaged (Ai) illuminated by a plurality of light sources was determined in the same manner as in the first example of the present invention. As a result of the simulation under the conditions of N = 12, a = 0.5, b = l. 55, a graph similar to Fig. 26 was obtained. In addition, the illuminance distribution based on the simulation result of the illuminance distribution over the entire area to be imaged (Ai) illuminated by multiple light sources under the condition of W: Ld = l: 1 and the target illuminance distribution. The difference was as shown in graph (3) of FIG.
[0321] 図 29中の（3)の曲線の両端付近が乱れて目標照度との差分が多く発生している理 由は、実施例 12の理由と似たような理由で、位置 P 力も位置 P までの光源が、  [0321] The reason why the vicinity of both ends of the curve (3) in Fig. 29 is disturbed and the difference from the target illuminance is large is similar to the reason of Example 12, and the position P force is also the position. Light sources up to P
n+ 1 2n+ l  n + 1 2n + l
位置 P力も位置 Pまでの光源の鏡像である虚光源であるので、撮像対象領域 (Ai) Since the position P force is also a virtual light source that is a mirror image of the light source up to position P, the imaging target area (Ai)
0 n 0 n
と光源までの距離や、光源の光の放射特性を理想的に設定できないためである。た だし、位置 Pと位置 P の間における側面鏡の位置を若干 P側に接近させたり、側 面鏡の角度を微妙に変化させたり、適切に設定することによって、撮像対象領域 (Ai )の両端付近における照度分布をある程度制御することができる。  This is because the distance to the light source and the radiation characteristics of the light from the light source cannot be ideally set. However, if the position of the side mirror between position P and position P is slightly closer to the P side, or the angle of the side mirror is slightly changed or set appropriately, the imaging area (Ai) The illuminance distribution near both ends can be controlled to some extent.
[0322] しかしながら、このままでも、その差分の最大値は、 ± 2. 5%程度であり、図 29のグ ラフ（1 )及び（2)に示される差分の最大値よりも小さくなつている。また、図 26に示さ れる差分の最大値よりも大きいが、このような差分の最大値は、部品の精度や組み立 ての精度の観点及び省エネルギーの観点のレ、ずれからも殆ど問題とならな!/、。一次 元 CCDで光量を電気信号に変換した後の電気信号の増幅率を変えてその差分を 補正しても、その増幅率の変化量は小さぐノイズの影響を受けることはほとんどない[0322] However, even if it remains as it is, the maximum value of the difference is about ± 2.5%, which is smaller than the maximum value of the difference shown in the graphs (1) and (2) of FIG. In addition, although the difference is larger than the maximum value shown in FIG. 26, such a maximum difference is hardly a problem from the viewpoints of component accuracy, assembly accuracy, and energy saving. ! / once Even if the gain of the electrical signal after changing the light amount into an electrical signal with the original CCD is changed and the difference is corrected, the amount of change in the amplification rate is hardly affected by the noise.
〇 Yes
[0323] 次に、複数の光源の各々から撮像領域までの距離の調整及び複数の光源から放 出される光の放射特性の調整の両方によって、撮像領域を照明する光の照度分布 を 1/cos4 Θの特性に一致させる照明装置化の概念を示す。 [0323] Next, the illuminance distribution of the light that illuminates the imaging region is 1 / cos by both adjusting the distance from each of the plurality of light sources to the imaging region and adjusting the radiation characteristics of the light emitted from the plurality of light sources. 4 Shows the concept of lighting equipment that matches the characteristics of Θ.
[0324] 図 36は、複複数の光源の各々から撮像領域 (Ai)までの距離の調整及び複数の光 源から放出される光の放射特性の調整の両方によって、撮像領域 (Ai)を照明する 光の照度分布を 1/cos4 Θの特性に一致させる照明装置を実現するための概念図 である。図 36 (a)は、その上面図であり、図 36 (b)は、その正面図である。 [0324] Fig. 36 illuminates the imaging area (Ai) by adjusting both the distance from each of the multiple light sources to the imaging area (Ai) and adjusting the radiation characteristics of the light emitted from the multiple light sources. It is a conceptual diagram for realizing an illumination device that matches the illuminance distribution of light with the 1 / cos 4 Θ characteristic. FIG. 36 (a) is a top view thereof, and FIG. 36 (b) is a front view thereof.
[0325] 図 36 (a)に示すように、撮像領域 (撮像対象領域） (Ai)における中心軸に沿った仮 想光源と撮像領域 (Ai)との間の距離 L0に対する仮想光源と撮像領域 (Ai)との間の 距離し' の比は、本発明の第 14の実施例で得られる値 L /L0 = cos4 6 の平方根、 k k k [0325] As shown in Fig. 36 (a), the virtual light source and the imaging region for the distance L0 between the virtual light source and the imaging region (Ai) along the central axis in the imaging region (imaging target region) (Ai) The ratio of the distance between (Ai) and the square root of the value L / L0 = cos 4 6 obtained in the fourteenth embodiment of the present invention, kkk
すなわち、 L， /LO = cos2 6 である。 That is, L, / LO = cos 2 6.
k k  k k
[0326] 図 36 (a)に示す図においては、主走査方向（Sx)に配置される複数の光源に対応 する凸レンズの焦点距離は、一定であり、主走査方向（Sx)に配置された複数の光源 に対応する照明レンズ (凸シリンダレンズ）（3)の焦点距離は、図 36に示すようにして 、変化する。図 36 (a)に示す照明装置の中央付近では、照明レンズの焦点位置に形 成される仮想の光源の放射特性のエンベロープが、図 31の（2)に示すように、分散 が強い偏平の楕円状になるように、相対的に短い焦点距離の照明レンズを用い、周 辺に向かってその偏平度を少なくするように焦点距離を徐々に長くしていき、途中、 図 33 (1)のような円形に近いエンベロープとする照明レンズを用いるのを経て、その 後は図 31の（3)に示すように、分散の少ない鋭い楕円状になるように、相対的に長 V、焦点距離の照明レンズを用 V、る。  In the diagram shown in FIG. 36 (a), the focal lengths of the convex lenses corresponding to the plurality of light sources arranged in the main scanning direction (Sx) are constant and arranged in the main scanning direction (Sx). The focal length of the illumination lens (convex cylinder lens) (3) corresponding to a plurality of light sources varies as shown in FIG. In the vicinity of the center of the illumination device shown in Fig. 36 (a), the envelope of the radiation characteristics of the virtual light source formed at the focal position of the illumination lens is flat with strong dispersion as shown in Fig. 31 (2). Use an illumination lens with a relatively short focal length so that it has an elliptical shape, and gradually increase the focal length to reduce its flatness toward the periphery. After using an illumination lens with a nearly circular envelope like this, after that, as shown in Fig. 31 (3), a relatively long V, focal length is obtained so that it becomes a sharp ellipse with little dispersion. Use an illumination lens.
[0327] 即ち、照明レンズの焦点位置に形成される仮想の光源の放射特性の楕円状のェン ベロープの形状は、前述の式 R' =T - cosB(k) a に従って変化させている。 That is, the shape of the elliptic envelope of the radiation characteristic of the virtual light source formed at the focal position of the illumination lens is changed according to the above-described equation R ′ = T−cos B (k) a .
k k k  k k k
[0328] 図 36に示す概念で照明装置化する場合においては、各光源の位置から照明対象 面（撮像領域）（Ai)までの距離が一定であるように、各光源を配置することができるの で、基板としての平面板に光源を設けることができる。その結果、照明装置をより容易 に製造すること力できる。なお、光源の数を 25個に設定してシミュレーションしたが、 図 36 (a)においては、光源の数は、 10個で示してある。 [0328] In the case where the lighting device is realized with the concept shown in FIG. 36, each light source can be arranged so that the distance from the position of each light source to the illumination target surface (imaging region) (Ai) is constant. of Thus, a light source can be provided on a flat plate as a substrate. As a result, the lighting device can be more easily manufactured. Although the simulation was performed with the number of light sources set to 25, in FIG. 36 (a), the number of light sources is shown as ten.
[0329] 図 36 (b)に示すように、副走査方向（Sy)においては、個々の発光源 LEDから放 出された光の光束を、その LEDに対応する凸レンズであるフードレンズによって、平 行光にした後、凸シリンダレンズである照明レンズを平行光として通過し、集束レンズ (4a) (又は集束ミラー）によって撮像対象領域 (Ai)に集束させる。なお、集束レンズ（ 4a) (又は集束ミラー）を、必ずしも揷入する必要はない。すなわち、原稿の浮きを考 慮する場合には、集束レンズ (又は集束ミラー）を用いないことが、好ましい。しかしな がら、この場合においても、一次元 CCD上に結像される画像の明度を、一定にする 目的を損ねることはない。 As shown in FIG. 36 (b), in the sub-scanning direction (Sy), the light flux emitted from each light emitting source LED is flattened by a hood lens that is a convex lens corresponding to the LED. After making the incident light, the light passes through the illumination lens, which is a convex cylinder lens, as parallel light, and is focused on the imaging target area (Ai) by the focusing lens (4a) (or the focusing mirror). Note that it is not always necessary to insert the focusing lens (4a) (or the focusing mirror). That is, it is preferable not to use a converging lens (or a converging mirror) when considering floating of the original. However, even in this case, the purpose of making the brightness of the image formed on the one-dimensional CCD constant is not impaired.
なお、以上述べた図 36に示す概念を装置化して第 1走行体に搭載する方法は、前 述の実施例 11の方法に準じており、当業者には容易に実施可能である。  Note that the method of embodying the concept shown in FIG. 36 and mounting it on the first traveling body is in accordance with the method of Example 11 described above, and can be easily implemented by those skilled in the art.
実施例 16  Example 16
[0330] 本発明の第 16の実施例は、複数の光源から放出される光の照明光軸の角度を調 整して撮像領域を照明する光の照度分布を 1/cos4 Θの特性に一致させる例を示 す。 In the sixteenth embodiment of the present invention, the illuminance distribution of the light that illuminates the imaging region by adjusting the angle of the illumination optical axis of the light emitted from the plurality of light sources has a characteristic of 1 / cos 4 Θ. An example of matching is shown below.
[0331] 図 37は、一次元 CCDに結像される画像の相対明度が一定となるような、撮像対象 領域 (Ai)を照明する複数の光源の具体的な配置を説明する図である。図 37は、図 23における撮像対象面の左側の拡大図に相当する。図 37における記号は、図 32に おける記号に対応するものである。  FIG. 37 is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate the imaging target area (Ai) such that the relative brightness of an image formed on the one-dimensional CCD is constant. FIG. 37 corresponds to an enlarged view on the left side of the imaging target surface in FIG. The symbols in Fig. 37 correspond to the symbols in Fig. 32.
[0332] 図 37に示すように、本発明の第 16の実施例では、撮像対象領域 (Ai)における照 度分布が、 1/cos4 Θの特性を有するように、複数の光源の個々の照明光軸の角度 を調整する。 As shown in FIG. 37, in the sixteenth embodiment of the present invention, the illumination distribution in the imaging target area (Ai) has the characteristic of 1 / cos 4 Θ. Adjust the angle of the illumination optical axis.
[0333] 前述の実施例 11〜； 15にお!/、て説明してきたのと同様に、照明対象領域 (Ai)から L0だけ離れた且つ照明対象領域 (Ai)と平行な場所を N分割することによって得られ た各分割点に点光源を置き、各分割点の位置を、それぞれ、 P , P , - - ·Ρとする。更  [0333] In the same manner as described in the above-mentioned embodiments 11 to 15;! /, A place separated from the illumination target area (Ai) by L0 and parallel to the illumination target area (Ai) is divided into N parts. A point light source is placed at each division point obtained by doing this, and the position of each division point is P 1, P 2,--· Ρ, respectively. Further
0 1 η に、その外側 PM1の位置に鏡面 (側面鏡）が配置している。この鏡面は、撮像対象 領域 (Ai)の範囲を分割した点に対応した光源配置位置上に置!/、た複数の光源から 放出される光束を反射させて、あた力、もその延長線上に光源があるかのように照明対 象領域 (Ai)の範囲を照射させている。ここで分割点 P , ···, P , Pの位置に対応し At 0 1 η, a mirror surface (side mirror) is placed at the position of the outside PM1. This mirror surface is the object to be imaged It is placed on the light source placement position corresponding to the point where the range of area (Ai) is divided! / Reflects the light beam emitted from multiple light sources, and whether the light source is on the extension line In this way, the illumination target area (Ai) is illuminated. Here, it corresponds to the position of the dividing points P 1,.
n 1 0  n 1 0
た側面鏡によって得られる虚像 (虚光源 VLS)の位置を、それぞれ、 P , P , ··· n+1 n + 2 The position of the virtual image (virtual light source VLS) obtained by the side mirror is P, P, ... n + 1 n + 2
, Ρ とする。そして、本発明の第 16の実施例においては、位置 Ρに位置した光源 , Ρ. In the sixteenth embodiment of the present invention, the light source located at position Ρ
2n+l k  2n + l k
力も放出される光の照明光軸を、照明対象面 (撮像領域）（Ai)の鉛直方向に対して 角度 /3 だけ傾斜させる (位置 Pにおける光源の光軸の角度が /3 である）。  The illumination optical axis of light that also emits force is tilted by an angle / 3 with respect to the vertical direction of the illumination target surface (imaging area) (Ai) (the angle of the optical axis of the light source at position P is / 3).
k k k  k k k
[0334] 今、照明対象領域 (Ai)から各光源までの距離 L0よりも遠くに離れた (その距離を L 00とする）照射対象領域の中心線 CL上に任意の点 P00を置いたとき、その任意の 点 P00から照明対象領域の両端に向けて結ばれる直線が中心線 CLとなす角度を β とする。このとき、中心線 CLからその角度 /3 の範囲内に含まれる位置 Pにおけ [0334] Now, when an arbitrary point P00 is placed on the center line CL of the irradiation target area that is farther than the distance L0 from the illumination target area (Ai) to each light source (the distance is L 00) Let β be the angle formed by the straight line connecting the arbitrary point P00 toward both ends of the illumination target area with the center line CL. At this time, at the position P included in the range of the angle / 3 from the center line CL.
00 00 k る光源の照明光軸の角度 /3 は、点 P00からその光源の位置 Pに向けて結ばれる直 The angle / 3 of the illumination optical axis of the 00 00 k light source is directly connected from the point P00 to the position P of the light source.
k k  k k
線が、撮像対象領域 (Ai)の中心線 CLとなす角度であるとする。一方、撮像対象領 域 (Ai)の中心線じしから、その角度 β までの範囲外に位置する光源の照明光軸の  It is assumed that the line is an angle formed with the center line CL of the imaging target area (Ai). On the other hand, the illumination optical axis of the light source located outside the range from the center line of the imaging target area (Ai) to its angle β
00  00
角度 /3 は、全て、その光源の位置と撮像対象領域 (Ai)の最端部とを結ぶ直線が、 k  For all angles / 3, the straight line connecting the position of the light source and the end of the imaging target area (Ai) is k
撮像対象領域 (Ai)の中心線 CLとなす角度であるとする。即ち、撮像対象領域 (Ai) の中心線 CLに対する、位置 Pにおける光源の照明光軸の角度は、 β であるので、  It is assumed that the angle is made with the center line CL of the imaging target area (Ai). That is, the angle of the illumination optical axis of the light source at the position P with respect to the center line CL of the imaging target area (Ai) is β.
k k  k k
β , β , ···， β ， ···， β である。  β, β, ···, β, ···, β.
0 1 k η  0 1 k η
[0335] ここで、撮像対象領域 (Ai)の中心線 CLから角度 /3 までの光源位置 Pに対する  [0335] Here, for the light source position P from the center line CL of the imaging target area (Ai) to the angle / 3
00 k  00 k
照明光軸の角度 /3 は k=0(/3 =0)から始まり、 kが大きくなるに従って大きくなるが  The illumination optical axis angle / 3 starts from k = 0 (/ 3 = 0) and increases as k increases.
k 0  k 0
、角度 /3 を超える光源位置 Pに対する照明光軸の角度 /3 は kが大きくなるに従つ  The angle / 3 of the illumination optical axis with respect to the light source position P exceeding the angle / 3 increases as k increases.
00 k k  00 k k
て小さくなつていき、 Pが Pとなったとき角度 β =0となる。また、言い換えると、角度 β 以上に位置する Ρの光源の光軸は Ρまで撮像対象領域 (Ai)の最端部に向くこ The angle β = 0 when P becomes P. In other words, the optical axis of the light source of 位置 located at an angle β or more should face the end of the imaging target area (Ai) up to Ρ.
00 k n 00 k n
とになる。  It becomes.
また、位置 P , P , ···, P における虚光源の位置及び照明光軸の向きを制  It also controls the position of the imaginary light source and the direction of the illumination optical axis at positions P 1, P 2,.
n+1 n+2 2n+l  n + 1 n + 2 2n + l
御することは困難である力 位置 P , P , ·'·Ρに配置された光源から放出される光の  Force that is difficult to control of light emitted from light sources located at positions P, P,
0 1 η  0 1 η
多くを照射対象面に照射するためには、側面鏡（平面鏡）の鏡面を、位置 Ρの光源 にできる限り近づける（平面鏡である側面鏡が位置 Ρの光源に接触するまで、側面 鏡を位置 Pnの光源に近づける。 )ことが好まし!/、。 In order to irradiate the surface to be irradiated with much, the mirror surface of the side mirror (plane mirror) should be as close as possible to the light source at position （(until the side mirror as a plane mirror contacts the light source at position 側面 Move the mirror closer to the light source at position Pn . ) I like it! /
[0336] なお、位置 Pの光源の外側に設けられる側面鏡と対をなす側面鏡 PM2が、撮像対 象領域 (Ai)の中心線に対して上半分の領域にも設けられ、位置 Pの光源の外側に 設けられる側面鏡とは、互いに平行に配置される。このため、側面鏡の対によって、 虚光源の鏡像である無限の数の虚光源が生じる力 この内、側面鏡で 2回以上の反 射で生ずる虚光源は、照明対象領域 (Ai)からかなり離れた位置に生じる。このため、 撮像対象領域 (Ai)における照度分布に対する虚光源の鏡像による寄与率は、著し く小さぐ無視してもなんら差し支えない。  [0336] A side mirror PM2 that forms a pair with a side mirror provided outside the light source at position P is also provided in the upper half area with respect to the center line of the imaging target area (Ai). The side mirrors provided outside the light source are arranged in parallel to each other. For this reason, an infinite number of imaginary light sources, which are mirror images of the imaginary light source, are generated by the pair of side mirrors. It occurs at a distant position. For this reason, the contribution ratio of the mirror image of the imaginary light source to the illuminance distribution in the imaging target area (Ai) is extremely small and can be ignored.
[0337] 次に、複数の光源によって照明される撮像対象領域 (Ai)のある任意の点 Mmにお ける相対照度 I (Mm)を求めることにする。照明対象領域 (撮像対象領域）（Ai)に対 する鉛直線と、光源から点 Mmに向力、つて放出される光の放射ベクトルの角度を αと すると、光源から照明対象領域 (Ai)までの距離力 S、 L0であるので、ある一つの光源 力、ら点 Mmまでの距離は、 LO/cos aとなる。そして、副走査方向（Sy)においては 光源から放出される光の光束が発散しな!/、ことを前提とすると、各光源から放出され る光によって照明される照明対象領域 (Ai)の点 Mmにおける光の強度は、各光源か ら点 Mmまでの距離 LO/cos aに逆比例する。さらに、その同一点 Mmでの面の傾 きによる受ける光束の減少度は cos aとなる。  Next, the relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) illuminated by a plurality of light sources is determined. From the light source to the illumination target area (Ai), the vertical line to the illumination target area (imaging target area) (Ai) and the angle of the radiation vector of the emitted light directed to the point Mm from the light source is α. Since the distance force S and L0 of a single light source force, the distance to the point Mm is LO / cos a. Assuming that the light beam emitted from the light source does not diverge in the sub-scanning direction (Sy), the point of the illumination target area (Ai) illuminated by the light emitted from each light source The intensity of light at Mm is inversely proportional to the distance LO / cos a from each light source to point Mm. Furthermore, the degree of decrease in the luminous flux due to the tilt of the surface at the same point Mm is cos a.
[0338] 一方、図 24 (b)に示すように、照明対象領域 (撮像対象領域） (Ai)に対する鉛直線 と角度 αをなす放射ベクトルの方向に光源から放出される光の強度は、光源から放 出される光の放射ベクトルの分布（エンベロープ）に依存する。現実の LEDなどの光 源の放射べ外ル分布 (エンベロープ）は複雑な形を成しているが、計算の都合上円 形ないしは楕円状で近似する。例えば、図 24の（1 )に示すように、光源から放出され る光の放射ベクトルのエンベロープが円形に近似できる場合には、光源の照明光軸 に対して角度 αをなす放射ベクトルの方向に光源から放出される光の強度は、 cos αだけ減少する。光源から放出される光の放射ベクトルのエンベロープが、楕円状に 近似できる場合には、照明対象領域 (撮像対象領域）（Ai)に対する鉛直線と角度 α をなす放射ベクトルの方向に光源から放出される光の強度の減少度は、その放射べ タトルのエンベロープの形状により、図 24の（2)に示すような cos2 α、図 24の（3)に 示すような cos4 α等のように近似することが可能である。 On the other hand, as shown in FIG. 24 (b), the intensity of light emitted from the light source in the direction of the radiation vector that forms an angle α with the vertical line with respect to the illumination target region (imaging target region) (Ai) Depends on the distribution (envelope) of the radiation vector of light emitted from. The radiation distribution (envelope) of a light source such as an actual LED has a complex shape, but it is approximated by a circle or ellipse for convenience of calculation. For example, as shown in (1) of FIG. 24, when the envelope of the radiation vector of the light emitted from the light source can be approximated to a circle, the direction of the radiation vector forming an angle α with respect to the illumination optical axis of the light source The intensity of light emitted from the light source is reduced by cos α. If the envelope of the radiation vector of the light emitted from the light source can be approximated to an ellipse, the light source is emitted in the direction of the radiation vector that forms an angle α with the vertical line with respect to the illumination target area (imaging target area) (Ai). The degree of decrease in light intensity depends on the shape of the envelope of the radiation vector, cos 2 α as shown in Fig. 24 (2), and in Fig. 24 (3). It is possible to approximate such as cos 4 α as shown.
[0339] 従って、複数の光源によって照明される照明対象領域 (Ai)のある任意の点 Mmに おける相対照度 I (Mm)は、 [0339] Therefore, the relative illuminance I (Mm) at an arbitrary point Mm in the illumination target area (Ai) illuminated by a plurality of light sources is
[0340] [数 27] [0340] [Equation 27]
2"+1 71 2 " +1 71
I(Mm) = Ak - cos2 ak 'cos - k ) (たたし、 ≤ k≤―) I (Mm) = A k -cos 2 a k 'cos- k ) (but ≤ k ≤―)
[0341] によって表される。ここで、 Aは、 k番目の光源が放出する光の総光量の相対値であ [0341] Where A is the relative value of the total amount of light emitted by the kth light source.
k  k
り、 α は、照明対象領域 (Ai)の鉛直線に対する点 Mmに向力、う k番目の光源の放射 k  Α is the direction force at point Mm with respect to the vertical line of the illumination target area (Ai), and the radiation of the kth light source k
ベクトルの角度である。また、 aは、その光源の放射ベクトルのエンベロープを近似す る係数である。例えば、図 24 (b)の（1)に示すように、光源の放射ベクトルのェンベロ ープが、円形に近い場合には、 a = lであり、光源の放射ベクトルのエンベロープが、 楕円状に近い場合には、 a〉lであり、図 24 (b)の（2)及び（3)に示すように、光源の 放射ベクトルのエンベロープの形状に依存して、例えば、 a = 2及び a = 3である。また 、光源の放射ベクトルのエンベロープが偏平していれば a < 1に近似できる。  The angle of the vector. A is a coefficient approximating the envelope of the radiation vector of the light source. For example, as shown in (1) of Fig. 24 (b), when the envelope of the light source radiation vector is close to a circle, a = l, and the envelope of the light source radiation vector is elliptical. In the near case, a> l, and as shown in (2) and (3) of Fig. 24 (b), depending on the shape of the envelope of the radiation vector of the light source, for example, a = 2 and a = 3. If the envelope of the radiation vector of the light source is flat, it can be approximated to a <1.
[0342] 特に、本発明の第 16の実施例においては、位置 Pに配置された光源から放出され [0342] In particular, in the sixteenth embodiment of the present invention, the light is emitted from the light source arranged at the position P.
k  k
て且つ照明対象領域 (Ai)の点 Mmに到達する光源の放射ベクトルは、照明対象領 域 (Ai)の鉛直線に対する位置 Pと点 Mmを結ぶ直線の角度が α であるが、照明対  The radiation vector of the light source that reaches the point Mm of the illumination target area (Ai) has a straight line angle α between the position P with respect to the vertical line of the illumination target area (Ai) and the point Mm.
k k  k k
象領域 (Ai)の鉛直線に対して、位置 Pに配置された光源の照明光軸が 0 kだけ傾  The illumination optical axis of the light source placed at position P is tilted by 0 k with respect to the vertical line of the elephant area (Ai)
k  k
斜しているため、位置 Pに配置された光源の照明光軸に対して角度 α - β をなす  Since it is slanted, it forms an angle α-β with the illumination optical axis of the light source arranged at position P.
k k k 放射ベクトルの光である。  k k k Radiation vector light.
[0343] このようにして、照明対象領域 (Ai)の中心線 (CL)から下半分に配置した光源の全 体によって照明される照明対象領域 (Ai)の全域にわたる照度分布を算出することが できる。また、得られた照度分布を中心線 (CUに対して対称に反転させれば、照明 対象領域 (Ai)の中心線 (CUから上半分に配置した光源の全体によつて照明される 照明対象領域 (Ai)の全域にわたる照度分布を得ることができる。そして、照明対象 領域 (Ai)の中心線 (CUから下半分に配置した光源の全体によつて照明される照明 対象領域 (Ai)の全域にわたる照度分布と、照明対象領域 (Ai)の中心線 (じ から 上半分に配置した光源の全体によつて照明される照明対象領域 (Ai)の全域にわた る照度分布とを加算すれば、全部の光源によって照明される照明対象領域 (Ai)の 全域にわたる照度分布を得ることができる（ただし、この計算をする場合、 P上に置い [0343] In this way, it is possible to calculate the illuminance distribution over the entire illumination target area (Ai) illuminated by the entire light source arranged in the lower half from the center line (CL) of the illumination target area (Ai). it can. In addition, if the obtained illuminance distribution is inverted symmetrically with respect to the center line (CU), the center line of the illumination target area (Ai) (illuminated by the entire light source placed in the upper half of the CU The illumination distribution over the entire area (Ai) can be obtained, and the center line of the illumination target area (Ai) (the illumination target area (Ai) illuminated by the whole light source placed in the lower half from the CU) can be obtained. The illumination distribution over the entire area and the center line of the illumination target area (Ai) (over the entire illumination target area (Ai) illuminated by the whole light source placed in the upper half The illuminance distribution over the entire area to be illuminated (Ai) illuminated by all the light sources can be obtained (however, if this calculation is performed, place it on P
0 た光源力 発する光束は中心線 (CU力 下半分を計算する場合と、上半分を計算 する場合の両者で用いるので、その光源の相対強度 Aを、その以外の位置に置い  The luminous flux emitted from the light source is the center line (used to calculate the lower half of the CU force and the upper half, so the relative intensity A of the light source is placed at other positions.
0  0
た光源の相対強度の 1/2として計算する必要がある）。  Calculated as 1/2 the relative intensity of the light source).
[0344] そこで、このようなモデルで得られる相対照度を、 [0344] Therefore, the relative illuminance obtained with such a model is
W: Ld= l : l . 5 ;  W: Ld = l: l. 5;
L00 = 2 X L0 ;  L00 = 2 X L0;
N= 12 ;及び  N = 12; and
a = 2  a = 2
の条件の下で、照明対象領域 (Ai)の全域にわたって計算する。  Under the above conditions, the calculation is performed over the entire illumination target area (Ai).
[0345] 図 38は、本発明の第 16の実際例における相対照度と目標の照度分布との差分に つ!/、てのシミュレーション結果を示す図である。 [0345] FIG. 38 is a diagram showing simulation results for the difference between the relative illuminance and the target illuminance distribution in the sixteenth practical example of the present invention.
[0346] 本発明の第 21の実施例に示す構成を備えた照明装置について、本発明の第 12 の実施例と同様の方法で、複数の光源によって照明される撮像対象領域 (Ai)の全 域にわたる照度分布を求めた。その結果、図 25と同様のグラフを得ることができた。 図 38は、複数の光源によって照明される撮像対象領域 (Ai)の全域にわたる照度分 布と目標の照度分布との差分の拡大図のみを示す。図 38は、撮像対象領域 ( の いずれの位置においても、得られた照度分布と目標の照度分布との差分を、撮像対 象領域 (Ai)の周辺部の照度が撮像対象領域 (Ai)の中央部の照度より大きくなるよう に、表示したものである。図 38のグラフにおいては、撮像対象領域 (Ai)の最端部に おける照度と撮像対象領域 (Ai)の中央部とがほとんど一致しており、図 38のグラフ に示される差分の最大値は、撮像対象領域 (Ai)におけるその最端部から 15%程度 内側の位置で + 8%強である。し力もながら、従来技術のように撮像対象領域 (Ai)を 均一に照明した場合には、撮像対象領域 (Ai)の中央部分で捨てる光量の割合が、 23%であるため、撮像対象領域 (Ai)を均一に照明する場合と比較すると、光源から 放出される光の利用効率を大幅に向上させることができる。また、この程度の差異な らば一次元 CCDで光量を電気信号に変換した後の電気信号の増幅率を変えてその 差分を補正しても、その増幅率の変化率は小さぐノイズの影響を受けることはほとん どない。 [0346] About the illuminating device having the configuration shown in the twenty-first embodiment of the present invention, the entire imaging target region (Ai) illuminated by the plurality of light sources is processed in the same manner as in the twelfth embodiment of the present invention. The illuminance distribution over the area was obtained. As a result, a graph similar to FIG. 25 was obtained. FIG. 38 shows only an enlarged view of the difference between the illuminance distribution and the target illuminance distribution over the entire area to be imaged (Ai) illuminated by a plurality of light sources. Figure 38 shows the difference between the obtained illuminance distribution and the target illuminance distribution at any position of the imaging target area (Ai), and the illuminance at the periphery of the imaging target area (Ai) In the graph of Fig. 38, the illuminance at the end of the imaging target area (Ai) and the central part of the imaging target area (Ai) are almost the same. 38, the maximum value of the difference shown in the graph of Fig. 38 is slightly more than + 8% at a position 15% inside from the extreme end in the imaging target area (Ai). Thus, when the imaging target area (Ai) is illuminated uniformly, the ratio of the amount of light discarded at the center of the imaging target area (Ai) is 23%, so the imaging target area (Ai) is illuminated uniformly. Compared to the case, the utilization efficiency of the light emitted from the light source can be greatly improved. If there is a difference of this level, change the amplification factor of the electric signal after converting the light amount into an electric signal with a one-dimensional CCD. Even if the difference is corrected, the rate of change in the amplification factor is hardly affected by the small noise.
[0347] 次に、複数の光源から放出される光の照明光軸の角度を調整することによって、撮 像領域 (Ai)を照明する光の照度分布を 1/cos4 Θの特性に一致させる照明装置化 の概念を示す。 [0347] Next, by adjusting the angle of the illumination optical axis of the light emitted from multiple light sources, the illuminance distribution of the light that illuminates the imaging area (Ai) is matched to the 1 / cos 4 Θ characteristic The concept of lighting equipment is shown.
[0348] 図 39は、複数の光源から放出される光の照明光軸の角度を調整することによって、 撮像領域 (Ai)を照明する光の照度分布を 1/cos4 Θの特性に一致させる照明装置 を実現するための概念図である。図 39 (a)は、その上面図であり、図 39 (b)は、その 正面図である。 [0348] Figure 39 shows that the illuminance distribution of the light that illuminates the imaging area (Ai) matches the 1 / cos 4 Θ characteristics by adjusting the angle of the illumination optical axis of the light emitted from multiple light sources. It is a conceptual diagram for implement | achieving an illuminating device. FIG. 39 (a) is a top view thereof, and FIG. 39 (b) is a front view thereof.
[0349] 図 39に示す照明装置においては、シミュレーションを前提とする図 37に示す照明 装置の構成よりも目標の照度分布を得ることを容易にするためのいくつかの事項を変 更している。  [0349] In the lighting device shown in Fig. 39, several items have been changed to make it easier to obtain the target illuminance distribution than the configuration of the lighting device shown in Fig. 37, which assumes simulation. .
[0350] 図 39に示す図においては、光源 LED及び凸レンズは、図 31に示すような仮想光 源を形成する。また、照明対象領域 (撮像領域）（Ai)の中心線に対して光源の照明 光軸を傾斜させる手段としては、図 34に示したもの同様に、凸シリンダレンズの照明 レンズ (3)の直後に配置したプリズムを用いることができる。図 37において複数の光 源の間隔は等しいが、図 39に示す照明装置においても、複数の光源それら自体の 間隔は等しい。し力、しながら、仮想光源の位置は、光軸の照明光軸が傾斜すると共 に、光源の照明光軸から変位して!/、る。光源の照明光軸に対する仮想光源の位置の 変位量にっレ、ては、撮像領域 (Ai)の中心線 (センターライン： CL)と撮像領域 (Ai) の中心線上のある点と撮像領域 (Ai)の端部を結ぶ直線 (エッジライン： EUとの間の 領域に含まれる仮想光源の間隔は、仮想光源の位置が端部に近いほど、大きくなる 。一方、撮像領域 (Ai)のエッジラインの外側の領域に含まれる仮想光源の間隔は、 仮想光源の位置が端部に近いほど、小さくなる。よって、シミュレーションを行った、 図 37に示される照明装置と同じ照明装置を得るためには、厳密には仮想光源の位 置の変位に対応して光源の位置を変位させる必要がある力 実際には、仮想光源の 位置の変位は、あまり大きな問題とならない。  In the diagram shown in FIG. 39, the light source LED and the convex lens form a virtual light source as shown in FIG. Also, as a means for inclining the illumination optical axis of the light source with respect to the center line of the illumination target area (imaging area) (Ai), as shown in FIG. 34, immediately after the illumination lens (3) of the convex cylinder lens Can be used. In FIG. 37, the intervals between the plurality of light sources are equal, but also in the illumination device shown in FIG. 39, the intervals between the plurality of light sources themselves are equal. However, the position of the virtual light source is displaced from the illumination optical axis of the light source while the illumination optical axis of the optical axis is inclined. Depending on the amount of displacement of the position of the virtual light source relative to the illumination optical axis of the light source, the center line (center line: CL) of the imaging area (Ai) and a point on the center line of the imaging area (Ai) and the imaging area ( The straight line connecting the edges of Ai) (edge line: the distance between the virtual light sources included in the area between the EU and the edge of the imaging area (Ai) increases as the position of the virtual light source is closer to the edges. The distance between the virtual light sources included in the area outside the line becomes smaller as the position of the virtual light source is closer to the edge, so that the simulated lighting device shown in FIG. Strictly speaking, it is necessary to shift the position of the light source in response to the displacement of the position of the virtual light source. Actually, the displacement of the position of the virtual light source is not a big problem.
[0351] また、エッジライン ELの内側の領域に含まれる照明レンズ (3)の放射特性は、 a = 2 、即ち、 cos aであり、エッジライン ELの外側の領域に含まれる照明レンズ（3)の放 射特性は、 a = 4、即ち、 cos4 aである。エッジライン ELの内側における照明レンズ（3 )の放射特性を相対的に発散型にして、撮像領域 (Ai)の中央部分における照度を 相対的に減少させると共に、エッジライン ELの外側における照明レンズ (3)の放射特 性を相対的に収束型にして、撮像領域 (Ai)の周辺部分における照度を相対的に増 加させる。その結果、図 38に示される差分のピークの大きさを低減することができる。 さらに、撮像領域 (Ai)の中央付近における照明レンズ (3)の放射特性を a = 1即ち c os aに設計するなど、本実施例の構成に他の実施例の構成を組み合わせることによ つて、図 38に示される差分のピークの大きさを、より低減すること力 Sできる。 [0351] The radiation characteristics of the illumination lens (3) included in the area inside the edge line EL is a = 2 That is, cos a, and the radiation characteristic of the illumination lens (3) included in the region outside the edge line EL is a = 4, that is, cos 4 a. The radiation characteristic of the illumination lens (3) inside the edge line EL is made relatively divergent, and the illuminance at the center of the imaging area (Ai) is relatively reduced, and the illumination lens ( The radiation characteristics of 3) are made relatively convergent, and the illuminance in the peripheral area of the imaging area (Ai) is relatively increased. As a result, the difference peak size shown in FIG. 38 can be reduced. Furthermore, by combining the configuration of this example with the configuration of the other examples, such as designing the radiation characteristics of the illumination lens (3) near the center of the imaging area (Ai) to be a = 1, i.e., c os a. The force S can further reduce the size of the difference peak shown in FIG.
[0352] 本発明の第 1 1〜； 16の実施例として典型的な構成を説明してきた力 本発明の第 1 ；!〜 16の実施例に記載された構成の組み合わせ、変形、及び一部の変更をすること は可能である。例えば、照明装置の製造の都合によって、複数の LEDを一体のュニ ットに統合したり、シリンダレンズアレイ及び/又はプリズムアレイを用いたり、シリンダ レンズの光軸をシフトさせたり、部品の単価をより低減することも可能となる。また、集 光レンズをフードレンズとして示した例についても、集光レンズを、 LEDとは独立に設 けることあでさる。 Forces that have been described as typical configurations of the first to sixteenth embodiments of the present invention. [0352] Combinations, modifications, and parts of configurations described in the first to sixteenth embodiments of the present invention. It is possible to make changes. For example, depending on the convenience of manufacturing the lighting device, multiple LEDs can be integrated into a single unit, a cylinder lens array and / or prism array can be used, the optical axis of the cylinder lens can be shifted, Can be further reduced. Also, in the example where the condensing lens is shown as a hood lens, the condensing lens can be installed independently of the LED.
[0353] また、光源に対して仮想光源を形成する手段として、発光源 LEDからの光束を、概 略平行光にした後、凸シリンダレンズで主走査方向（Sx)においてのみ、凸シリンダレ ンズの焦点の位置に、一旦集束させることによって、仮想光源を形成することを説明 してきた。し力、しながら、凸シリンダレンズを凹シリンダレンズに取り替えても、同様に、 光源から仮想光源を形成することができる。  [0353] Further, as a means for forming a virtual light source with respect to the light source, the light beam from the light source LED is made to be substantially parallel light, and then the convex cylinder lens is used only in the main scanning direction (Sx) with a convex cylinder lens. It has been explained that a virtual light source is formed by focusing once on the focal point. However, even if the convex cylinder lens is replaced with a concave cylinder lens, a virtual light source can be formed from the light source.
[0354] 図 40は、凹シリンダレンズを用いて光源から仮想光源 VLSを形成することを説明す る図である。図 40 (a)は、凹シリンダレンズを用いる光学系の上面図であり、図 40 (b) は、凹シリンダレンズを用いる光学系の正面図である。図 49に示すように、発光光源 LEDから放出される光の光束を、凸レンズを用いて概略平行光にした後、凹シリンダ レンズによって、主走査方向（Sx)にのみ、発散させること力 Sできる。このとき、光源に 対する仮想光源の位置は、図 49に示すように、凹シリンダレンズ (焦点距離 f l )の焦 点に形成される。すなわち、凹シリンダレンズを用いることによって、凹シリンダレンズ よりも光源の側に仮想光源 VLSを位置させることができる（凸シリンダレンズを用いる 場合には、凹シリンダレンズよりも撮像領域 (Ai)側に仮想光源が形成される）。このた め、凹シリンダレンズの焦点距離 flを適宜選択することによって、照明装置をより小 型化することが可能となる。 FIG. 40 is a diagram for explaining the formation of the virtual light source VLS from the light source using the concave cylinder lens. 40 (a) is a top view of an optical system using a concave cylinder lens, and FIG. 40 (b) is a front view of the optical system using a concave cylinder lens. As shown in FIG. 49, the light flux emitted from the light emitting light source LED is made to be approximately parallel light using a convex lens, and then can be diverged only by the concave cylinder lens in the main scanning direction (Sx). . At this time, the position of the virtual light source with respect to the light source is formed at the focal point of the concave cylinder lens (focal length fl) as shown in FIG. That is, by using a concave cylinder lens, a concave cylinder lens The virtual light source VLS can be positioned closer to the light source side (when a convex cylinder lens is used, the virtual light source is formed on the imaging region (Ai) side than the concave cylinder lens). For this reason, the illumination device can be made smaller by appropriately selecting the focal length fl of the concave cylinder lens.
[0355] また、光源には出来るだけ小さな体積で発光するものを用いるのが望ましいので L ED (発光ダイオード）が適している。赤 (R)、緑 (G)、青（B)などの単色光を単体で発 光体としたものだけでなぐそれらの複数を一体で封入して白色光としたものや、白色 LEDのように青色 LEDや、紫色 LEDなどの発光光束を蛍光体に当てて白色光を得 るようなものも本発明の装置に適用できる。また、ネオン管や、小型高圧水銀灯など の放電灯や、小さく球状にしたフィラメント電球なども、適用可能である。  [0355] Since it is desirable to use a light source that emits light in as small a volume as possible, LED (light emitting diode) is suitable. A single light source such as red (R), green (G), blue (B), etc. alone is used as a light emitter. In addition, a device such as a blue LED or a purple LED that emits a luminous flux to a phosphor to obtain white light can be applied to the apparatus of the present invention. In addition, a neon tube, a discharge lamp such as a small high-pressure mercury lamp, or a small bulb-shaped filament bulb can be applied.
[0356] 最後に、本発明の実施形態及び実施例に用いることができる、主要な光学部品の 形態を説明する。  [0356] Finally, modes of main optical components that can be used in the embodiments and examples of the present invention will be described.
[0357] 図 41及び図 42は、本発明の実施形態及び実施例に用いることができる光学部品 を説明する図である。  41 and 42 are diagrams illustrating optical components that can be used in the embodiments and examples of the present invention.
[0358] 図 41 (a)は、第一のシリンダレンズアレイの例を示す図である。図 41 (a)に示すよう な第一のシリンダレンズアレイは、互いに隣接して配置された複数の凸のシリンダレ ンズで構成され、本発明の実施形態及び実施例においては、照明レンズとして使用 され得る。  FIG. 41 (a) is a diagram showing an example of the first cylinder lens array. The first cylinder lens array as shown in FIG. 41 (a) is composed of a plurality of convex cylinder lenses arranged adjacent to each other, and is used as an illumination lens in the embodiments and examples of the present invention. obtain.
[0359] 図 41 (b)は、第二のシリンダレンズアレイの例を示す図である。図 41 (b)に示すよう な第一のシリンダレンズアレイは、互いに隣接して配置された複数の凹のシリンダレ ンズで構成され、本発明の実施形態及び実施例においては、照明レンズとして使用 され得る。  FIG. 41 (b) is a diagram showing an example of the second cylinder lens array. The first cylinder lens array as shown in FIG. 41 (b) is composed of a plurality of concave cylinder lenses arranged adjacent to each other, and is used as an illumination lens in the embodiments and examples of the present invention. obtain.
[0360] 図 41 (c)は、第一のシリンダレンズの例を示す図である。図 41 (c)に示すような第 一のシリンダレンズは、平凸の断面を有し、本発明の実施形態及び実施例において は、集束レンズとして使用され得る。  FIG. 41 (c) is a diagram showing an example of the first cylinder lens. The first cylinder lens as shown in FIG. 41 (c) has a plano-convex cross section, and can be used as a focusing lens in the embodiments and examples of the present invention.
[0361] 図 41 (d)は、第二のシリンダレンズの例を示す図である。図 41 (d)に示すような第 二のシリンダレンズは、両凸の断面を有し、本発明の実施形態及び実施例において は、集束レンズとして使用され得る。 [0362] 図 41 (e)は、放物面鏡又は楕円面鏡の例を示す図である。図 41 (e)に示すような 放物面鏡又は楕円面鏡は、ある一つの方向において、放物面又は楕円面の断面を 有し、且つ、その方向と垂直な方向には、平行平面の断面を有するミラーである。図 41 (e)に示すような放物面鏡又は楕円面鏡は、本発明の実施形態及び実施例にお いては、集束ミラーとして使用され得る。図 41 (e)に示すような放物面鏡又は楕円面 鏡の形状は、光輝アルミ薄板を用いて、容易に形成されるので、図 41 (e)に示すよう な放物面鏡又は楕円面鏡を製造するコストを、低減することができる。 FIG. 41 (d) is a diagram showing an example of the second cylinder lens. The second cylinder lens as shown in FIG. 41 (d) has a biconvex cross section, and can be used as a focusing lens in the embodiments and examples of the present invention. [0362] Fig. 41 (e) is a diagram showing an example of a parabolic mirror or an ellipsoidal mirror. A parabolic mirror or ellipsoidal mirror as shown in Fig. 41 (e) has a parabolic or elliptical cross section in one direction and a parallel plane in a direction perpendicular to that direction. It is a mirror which has the cross section. A parabolic mirror or an ellipsoidal mirror as shown in FIG. 41 (e) can be used as a focusing mirror in the embodiments and examples of the present invention. The shape of a parabolic mirror or ellipsoidal mirror as shown in Fig. 41 (e) can be easily formed using a bright aluminum thin plate, so a parabolic mirror or ellipse as shown in Fig. 41 (e) is used. The cost for manufacturing the surface mirror can be reduced.
[0363] 図 41 (f)は、平面鏡の例を示す図である。図 41 (f)に示すような平面鏡は、本発明 の実施形態及び実施例においては、変向ミラー及び折り返しミラーとして使用され得 る。ここで、図 41 (f)に示すような平面鏡を、変向ミラーとして用いる場合には、画像 情報を備えた光を反射させるために、図 41 (f)に示すような平面鏡は、ガラスの一面 を鏡面とした平面鏡であることが好ましい。また、図 41 (f)に示すような平面鏡を、折り 返しミラーとして用いる場合には、図 41 (f)に示すような平面鏡は、光輝アルミ板を用 V、て製造された平面鏡であってもよレ、。  FIG. 41 (f) is a diagram showing an example of a plane mirror. A plane mirror as shown in FIG. 41 (f) can be used as a turning mirror and a folding mirror in the embodiments and examples of the present invention. Here, when a plane mirror as shown in FIG. 41 (f) is used as a turning mirror, in order to reflect light with image information, the plane mirror as shown in FIG. A plane mirror having one surface as a mirror surface is preferable. In addition, when a plane mirror as shown in FIG. 41 (f) is used as a folding mirror, the plane mirror as shown in FIG. 41 (f) is a plane mirror manufactured using a bright aluminum plate V. Moyore.
[0364] 図 42 (a)は、凸シリンダレンズを示す図である。図 42 (a)に示すような凸シリンダレ ンズは、本発明の実施形態及び実施例においては、照明レンズとして使用され得る。  FIG. 42 (a) is a diagram showing a convex cylinder lens. A convex cylinder lens as shown in FIG. 42 (a) can be used as an illumination lens in the embodiments and examples of the present invention.
[0365] 図 42 (b)は、凹シリンダレンズを示す図である。図 42 (a)に示すような凹シリンダレ ンズは、本発明の実施形態及び実施例においては、照明レンズとして使用され得る。  FIG. 42 (b) is a diagram showing a concave cylinder lens. A concave cylinder lens as shown in FIG. 42 (a) can be used as an illumination lens in the embodiments and examples of the present invention.
[0366] 図 42 (c)は、プリズムを示す図である。図 42 (c)に示すようなプリズムは、本発明の 実施形態及び実施例においては、照明光軸を折り曲げる（偏向させる）光学素子とし て使用され得る。  FIG. 42 (c) is a diagram showing a prism. A prism as shown in FIG. 42 (c) can be used as an optical element that bends (deflects) the illumination optical axis in the embodiments and examples of the present invention.
[0367] 以上、本発明の実施の形態及び実施例を具体的に説明してきたが、本発明は、こ れらの実施の形態及び実施例に限定されるものではなぐこれら本発明の実施の形 態及び実施例を、本発明の主旨及び範囲を逸脱することなぐ変更又は変形するこ と力 Sできる。  [0367] While the embodiments and examples of the present invention have been specifically described above, the present invention is not limited to these embodiments and examples. It is possible to change or modify the embodiments and examples without departing from the spirit and scope of the present invention.

Claims

請求の範囲 The scope of the claims
[1] 光源力 放出される光で原稿を照明する原稿照明方法において、  [1] Light source power In an original illumination method for illuminating an original with emitted light,
少なくとも第一の方向に配置された複数の光源から放出される光を重畳させて、該 重畳された光で原稿を照明すること、及び、該複数の光源から放出される光の光束 を、該第一の方向において、該複数の光源における相互に隣接する光源の間の間 隔の二倍以上に拡散させることを含むことを特徴とする原稿照明方法。  The light emitted from the plurality of light sources arranged in at least the first direction is superimposed, the original is illuminated with the superimposed light, and the light flux of the light emitted from the plurality of light sources is A method of illuminating a document, comprising: diffusing in a first direction at least twice the interval between adjacent light sources in the plurality of light sources.
[2] 前記複数の光源から放出される光の光束の少なくとも一部を、前記第一の方向と垂 直な第二の方向において、収束させることをさらに含むことを特徴とする請求項 1に 記載の原稿照明方法。  [2] The method according to claim 1, further comprising converging at least a part of a light flux of light emitted from the plurality of light sources in a second direction perpendicular to the first direction. The document illumination method described.
[3] 光源力 放出される光で原稿を照明する原稿照明装置において、  [3] Light source power In a document illumination device that illuminates a document with emitted light,
少なくとも第一の方向に配置された複数の光源、及び、該複数の光源から放出され る光を重畳させて、該重畳された光で原稿を照明すると共に、該複数の光源から放 出される光の光束を、該第一の方向において、該複数の光源における相互に隣接 する光源の間の間隔の二倍以上に拡散させる光学系を含むことを特徴とする原稿照 明装置。  A plurality of light sources arranged in at least a first direction and light emitted from the plurality of light sources are superimposed to illuminate a document with the superimposed light and light emitted from the plurality of light sources The original illuminating apparatus includes an optical system that diffuses the luminous flux in the first direction at least twice the interval between the light sources adjacent to each other in the plurality of light sources.
[4] 光源から放出される光で原稿を照明する原稿照明装置を含むと共に該原稿照明 装置によって照明された該原稿の画像を読み取る画像読取装置において、  [4] In an image reading apparatus that includes a document illuminating device that illuminates a document with light emitted from a light source and reads an image of the document illuminated by the document illuminating device,
該原稿照明装置は、少なくとも第一の方向に配置された複数の光源、及び、該複 数の光源から放出される光を重畳させて、該重畳された光で原稿を照明すると共に、 該複数の光源から放出される光の光束を、該第一の方向において、該複数の光源 における相互に隣接する光源の間の間隔の二倍以上に拡散させる光学系を含むこ とを特徴とする画像読取装置。  The document illumination device illuminates a document with the plurality of light sources arranged in at least the first direction and the light emitted from the plurality of light sources, and illuminates the document with the superimposed light. And an optical system for diffusing the light beam emitted from the light source in the first direction to at least twice the interval between the adjacent light sources in the plurality of light sources. Reader.
[5] 少なくとも第一の方向に配置された複数の光源、及び、該複数の光源から放出され る光を重畳させて、該重畳された光で原稿を照明すると共に、該複数の光源から放 出される光の光束を、該第一の方向において、該複数の光源における相互に隣接 する光源の間の間隔以上に拡散させる照明光学系を含む原稿照明装置、  [5] A plurality of light sources arranged in at least the first direction and light emitted from the plurality of light sources are superimposed to illuminate the original with the superimposed light and are emitted from the plurality of light sources. A document illuminating device including an illumination optical system that diffuses a luminous flux of emitted light in the first direction to be equal to or greater than an interval between light sources adjacent to each other in the plurality of light sources;
該原稿照明装置によって照明された原稿から散乱又は反射された光を結像させる 結像光学系、並びに、 該結像光学系によって結像された画像を撮像する撮像素子 を含む、該原稿の画像を読み取る画像読取装置にお!、て、 An imaging optical system that forms an image of light scattered or reflected from the original illuminated by the original illumination device; and In an image reading apparatus that reads an image of the document including an imaging device that captures an image formed by the imaging optical system!
該複数の光源は、該原稿における該原稿を照明する光の照度分布特性が、該撮 像素子に該結像光学系によって結像される画像の明度の分布特性と逆であるように 、配置されることを特徴とする画像読取装置。  The plurality of light sources are arranged so that an illuminance distribution characteristic of light illuminating the original on the original is opposite to a lightness distribution characteristic of an image formed on the imaging element by the imaging optical system. An image reading apparatus.
PCT/JP2007/067009 2006-09-15 2007-08-31 Document illuminating method, document illuminating device, and image reader WO2008032588A1 (en)

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