WO2006129151A1 - System of illumination for videoprojector using a plurality of lamps - Google Patents
System of illumination for videoprojector using a plurality of lamps Download PDFInfo
- Publication number
- WO2006129151A1 WO2006129151A1 PCT/IB2006/001325 IB2006001325W WO2006129151A1 WO 2006129151 A1 WO2006129151 A1 WO 2006129151A1 IB 2006001325 W IB2006001325 W IB 2006001325W WO 2006129151 A1 WO2006129151 A1 WO 2006129151A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- illumination
- light beam
- lamps
- videoprojectoraccording
- integrating bar
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/12—Beam splitting or combining systems operating by refraction only
- G02B27/123—The splitting element being a lens or a system of lenses, including arrays and surfaces with refractive power
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
- G02B27/0938—Using specific optical elements
- G02B27/095—Refractive optical elements
- G02B27/0972—Prisms
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
- G02B27/0938—Using specific optical elements
- G02B27/0994—Fibers, light pipes
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3141—Constructional details thereof
- H04N9/315—Modulator illumination systems
- H04N9/3152—Modulator illumination systems for shaping the light beam
Definitions
- the present invention relates to a system of illumination for videoprojector according to the preamble of claim 1.
- small electromechanical devices such as, for instance, DMD (Digital Micromirror Device), LCD (Liquid Cristal Display) and LCoS (Liquid Cristal on Silicon) devices are widely used for manufacturing videoprojectors, because they allow to obtain small, light apparatus producing a high-quality image.
- DMD Digital Micromirror Device
- LCD Liquid Cristal Display
- LCoS Liquid Cristal on Silicon
- a DMD device or panel consists of a set of small square mirrors typically made of aluminium and having a side approximately 13 ⁇ m long, each of which represents an element of the image to be projected, i.e. a pixel.
- the mirrors can rotate about a diagonal at a certain angle, e.g. ⁇ 12 degrees, and the rotation in either direction is produced by two electrodes located under the mirror, on opposite sides with respect to the axis of rotation.
- the light strikes the mirror at an angle of approximately 26 degrees relative to the perpendicular of the plane of the mirror, when the latter is "at rest", i.e. when it is not attracted by either electrode.
- a projection lens which focuses the image onto the screen.
- a pixel consists of a layer of liquid crystals enclosed between two plates, or electrodes, which are arranged parallel to each other; when a light beam is sent to a plate, the quantity of light going through the liquid crystal layer can be controlled by means of the voltage applied to the electrodes and by using suitable polarizers.
- transmission-type devices which generally consist of LCD devices
- both electrodes are transparent, therefore the light beam enters one plate, and exits from the other plate, and is then sent to the screen.
- reflection-type devices which generally consist of LCoS devices
- one plate is transparent and the other one is reflective, so that the light beam goes through the transparent plate, is reflected by the reflective plate, goes through ' the transparent plate again and is finally sent to the screen.
- the set of pixels represents the active surface of the panel, on which the image to be projected onto the screen is formed.
- each system of illumination for videoprojector may use one or more devices for the formation of the image, in particular DMD, LCD or LCoS devices; preferably, each system of illumination employs devices of the same type.
- DMD digital versatile disk
- LCD liquid crystal display
- LCoS devices preferably, each system of illumination employs devices of the same type.
- the choice of the illuminating device used is of great importance.
- systems of illumination for videoprojector use systems of illumination consisting of arc lamps, which provide a high luminous intensity.
- Fig. Ia shows a diagram of a system of illumination for videoprojector according to the prior art.
- a lamp 1 emits a parallel light beam having a substantially circular section as said lamp 1 is provided with a parabolic shaped reflector.
- An aspheric condenser sends said light beam to an integrating bar 3, consisting of a parallelepiped made of optical-glass having an inlet face 4 and an outlet face 5,which allows to uniform the light beam exiting from the aspheric condenser 2.
- said aspheric condenser 2 sends a conical light beam, represented by the triangle f-f-f ' in the horizontal projection of Fig. Ia, to the integrating bar 3; said conical light beam is intercepted by the inlet face 4, so as to form a circle having a diameter d on the surface of said inlet face 4.
- Fig. Ib shows the inlet face 4 of the integrating bar 3 and the circle having a diameter d which indicates the area illuminated by the conical light beam striking said inlet face.
- the angular aperture of the conical light beam i.e. the angle in the vertex f of the cone, is equal to an angle 2 ⁇ in the representation of Fig. Ia.
- the light beam exiting from the integrating bar 3 is collected by a system of converging lenses 6, known as "relay lenses”, and is then sent to means, e.g. a prism system not shown in Fig. Ia, adapted to break up the light beam, according to known techniques, into the three primary monochromatic components it is composed of, in particular the red, green and blue monochromatic components.
- a system of converging lenses 6, known as "relay lenses” e.g. a prism system not shown in Fig. Ia, adapted to break up the light beam, according to known techniques, into the three primary monochromatic components it is composed of, in particular the red, green and blue monochromatic components.
- Said primary monochromatic components are then directed to the active surface of several devices for the formation of the image, e.g. three DMDs (Digital Micromirror Devices), not shown in the drawings for simplicity's sake.
- DMDs Digital Micromirror Devices
- the angular aperture of the conical light beam entering said integrating bar 3, and thus the angle 2 ⁇ , is selected so as to use in the appropriate conditions the various components of the system of illumination which convey the light beam to the devices for the formation of the image, thereby maximizing the light transfer.
- a higher lamp power causes the entire system of illumination to become hotter and therefore more difficult to cool, thus requiring bulky cooling solutions.
- An increase in the brightness of a system of illumination for videoprojector may also be obtained by using the known arrangement shown in Fig.
- both lamps 1, 1' emit a parallel light beam having a substantially circular section, since said lamps 1, 1' are provided with a parabolic shaped reflector; the use of lamps provided with a parabolic shaped reflector requires the use of collimating means, which allow to converge the parallel light beam generated by the lamps.
- each of said lamps 1, 1' is associated with a collimating means, in particular an aspheric condenser 2, 2', which allows to converge the light beam into the integrating bar 3.
- Each lamp 1, 1' generates a light beam having a magnitude equal to 2 ⁇ ; the angle of incidence of the light beam when it enters the integrating bar 3 is equal to the sum of the angles of the light beams generated by both lamps 1, 1', and therefore its magnitude is equal to 4 ⁇ .
- the overall angular aperture 4 ⁇ of the light beam exiting from the integrating bar 3 turns out to be twice as the angular aperture of the light beam exiting from the integrating bar 3 produced by a single lamp.
- Fig. 2 clearly shows that, since the angular aperture 4 ⁇ of the light beam exiting from the integrating bar 3 is wider, in order to intercept a portion as big as possible of the light beam it is necessary to increase the dimensions of the system of converging lenses 6 and of the other means, eg. prisms not shown in the drawings, which allow to convey the light beam to the devices for the formation of the image, e.g. DMD devices. This inevitably leads to increased costs of the components used in the system of illumination.
- the components normally used in the systems of illumination known in the art require the use of light beams having a limited angular aperture. Consequently, if the system of illumination employs a light beam exiting from the integrating bar 3 with a very wide angular aperture, at least a portion of said light beam will not be used. This will lead to a lower brightness level of the whole system of illumination; furthermore, the unused portion of the light beam will scatter in the system of illumination, thus causing a considerable drop in contrast. It follows that the expected brightness increase due to a doubled light source will not be reached in full.
- the object of the present invention is to provide a system of illumination using a plurality of lamps which, by overcoming the above drawbacks, allows to manufacture high-brightness and high-contrast videoprojectors without jeopardizing the reliability of the videoprojector itself and at the same time avoiding any increase in the costs of the components used for its production.
- Ia 3 Ib, Ic show a first system of illumination for videoprojector according to the prior art
- FIG. 2 shows a second system of illumination for videoprojector according to the prior art
- FIG. 3a, 3b and 3c show a first embodiment of a system of illumination for videoprojector according to the invention
- FIG. 4 shows a second embodiment of a system of illumination for videoprojector according to the invention
- FIG. 5 shows a third embodiment of a system of illumination for videoprojector according to the invention.
- FIG. 3a shows a first embodiment of a system of illumination for videoprojector according to the invention; said system of illumination comprises a plurality of lamps.
- Said plurality of lamps comprises two lamps 1, 1' which, for simplicity's sake, are supposed to be identical; it is clear that the following considerations may be easily extended to a system of illumination comprising more than two lamps, even being different from one another.
- Each of said lamps 1, 1' emits a parallel light beam having a substantially circular section, in that said lamps 1, 1 ' are provided with a parabolic shaped reflector.
- lamps 1, 1' provided with a parabolic shaped reflector requires that each of said lamps 1, I' be associated with a collimating means, in particular an aspheric condenser 2, 2', which allows to converge the parallel light beam generated by the lamps 1, 1'.
- the lamps 1, 1' are associated with two transparent deflecting prisms, being in particular of the "wedge" type and preferably small in size, designated with reference numbers 8 and 8' in Fig. 3a; in particular, in the representation of Fig. 3a said transparent deflecting prisms 8, 8' are positioned between the aspheric condensers 2 and 2', respectively, and an integrating bar 3.
- the transparent deflecting prism 8 deflects the light beams coming from the lamp 1 and from the respective aspheric condenser 2, so that a first external ray 9 undergoes such a deflection as to generate a light ray 9', which strikes an inlet face 4 of the integrating bar 3 at an angle ⁇ , i.e. with an angular aperture being equal to half the angular aperture of the light beam entering said integrating bar 3, shown in Fig. Ia 5 when a single lamp 1 is used which lamp is adapted to generate a light beam having an angular aperture equal to 2 ⁇ .
- a second external ray 10 of the light beam generated by the lamp 1 is deflected by the transparent deflecting prism 8 so as to undergo a minimum deflection.
- the transparent deflecting prism 8' deflects the light beam coming from the lamp I 1 and from the respective aspheric condenser 2' so that a first external ray 11 undergoes such a deflection as to generate a light ray 11 ' striking said inlet face 4 of the integrating bar 3 at the same aforementioned angle ⁇ , whereas a second external ray 12 undergoes a minimum deflection.
- Fig. 3b shows the inlet face 4 of the integrating bar 3, on which of course two illuminated areas appear, each having a diameter d, instead of a single area as in the representation of Fig. Ib.
- Fig. 3c shows an outlet face 5 of the integrating bar 3, which face, due to the multiple reflections taking place within the integrating bar 3, is evenly illuminated.
- the conical light beam exiting from the integrating bar 3 has an angular aperture being equal to that of the conical light beam entering the integrating bar 3; it follows that, also with reference to the representation of Fig. 3a, the angle 2 ⁇ turns out to be equal to the angle 2 ⁇ .
- the light beam exiting from the integrating bar 3 is collected by a system of converging lenses 6, known in particular as "relay lenses", and is then sent to decompose means, e.g.
- a prism system not shown in Fig. 3a, adapted to divide the light beam, according to known techniques, into the three red, green and blue primary monochromatic components.
- Said primary monochromatic components are further directed toward the active surface of devices for the formation of the image, e.g. three DMDs (Digital Micromirror Devices), not shown in the illustrations.
- DMDs Digital Micromirror Devices
- the devices for the formation of the image which for instance may comprise three DMD, LCD or LCoS devices, one may use the same components, in particular "relay lenses” 6 and prisms not shown in the drawings, as those used in systems of illumination for videoprojector using just one lamp 1, thus with no increase in the costs of the components used in the system of illumination.
- the use of the transparent deflecting prisms 8, 8' also allows to obtain a light beam exiting from the integrating bar 3 having a narrow angular aperture, so as to allow for a full utilization of the whole light beam in the system of illumination for videoprojector according to the present invention, thereby preventing any brightness and contrast reduction phenomena from arising in the entire system of illumination. Furthermore, in the system of illumination according to the present invention it is possible to turn on the lamps 1, 1' at a power being lower than the nominal power, thereby obtaining a longer life of said lamps 1, 1'.
- the light beam produced by the lamps 1, 1' is divided, according to a known technique, into the three red, green and blue primary monochromatic components; these are then sent to a plurality of devices for the formation of the image to be projected, e.g. to three different DMD devices.
- said system of illumination may advantageously comprise a rotating wheel, also known as colour wheel, designated 13 in Fig. 4 and positioned between the transparent deflecting prisms 8, 8' and the inlet face 4 of the integrating bar 3.
- Fig. 5 shows a further embodiment of the system of illumination for videoprojector according to the present invention, which comprises a plurality of lamps 14, 14'. Said lamps 14, 14' are provided with an elliptic shaped reflector adapted to generate a conical light beam; as a result, this solution does not require the use of collimating means associated with each of said lamps 14, 14' in order to converge the light beam.
- the transparent deflecting prisms 8, 8' are positioned between the lamps 14, 14' and the inlet face 4 of the integrating bar 3.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Projection Apparatus (AREA)
- Non-Portable Lighting Devices Or Systems Thereof (AREA)
- Devices For Indicating Variable Information By Combining Individual Elements (AREA)
Abstract
A system of illumination for videoprojector is described, which comprises: - a plurality of lamps (1, 1', 14, 14') adapted to generate a light beam; - an integrating bar (3), in particular comprising an inlet face (4) and an outlet face (5), which allows to uniform the light beam generated by said plurality of lamps (1, 1', 14, 14'); - a system of converging lenses (6), adapted to collect the light beam exiting from said integrating bar (3); wherein each lamp (1, 1', 14, 14') of said plurality of lamps (1, 1', 14, 14') is associated with a transparent deflecting prism (8, 8'), which allows to reduce the angular aperture of the light beam generated by said plurality of lamps (1, 1', 14, 14').
Description
"SYSTEM OF ILLUMINATION FOR VIDEOPROJECTOR USING A PLURALITY OF LAMPS"
DESCRIPTION
The present invention relates to a system of illumination for videoprojector according to the preamble of claim 1.
Nowadays, small electromechanical devices such as, for instance, DMD (Digital Micromirror Device), LCD (Liquid Cristal Display) and LCoS (Liquid Cristal on Silicon) devices are widely used for manufacturing videoprojectors, because they allow to obtain small, light apparatus producing a high-quality image.
A DMD device or panel consists of a set of small square mirrors typically made of aluminium and having a side approximately 13 μm long, each of which represents an element of the image to be projected, i.e. a pixel. The mirrors can rotate about a diagonal at a certain angle, e.g. ± 12 degrees, and the rotation in either direction is produced by two electrodes located under the mirror, on opposite sides with respect to the axis of rotation. The light strikes the mirror at an angle of approximately 26 degrees relative to the perpendicular of the plane of the mirror, when the latter is "at rest", i.e. when it is not attracted by either electrode. Between the DMD device and the screen there is a projection lens, which focuses the image onto the screen.
If the mirror is turned in one direction, the light striking it will be reflected so as not to enter the projection lens, and thus it will not be sent to the screen; therefore, the pixel will be inactive, i.e. "off; if the rotation takes place in the opposite direction, the pixel will be active, i.e. "on", in that the reflection will be sent to a screen. In LCD and LCoS devices, a pixel consists of a layer of liquid crystals enclosed between two plates, or electrodes, which are arranged parallel to each other; when a light beam is sent to a plate, the quantity of light going through the liquid crystal layer can be controlled by means of the voltage applied to the electrodes and by using suitable polarizers. In the so-called "transmission-type" devices, which generally consist of LCD devices, both electrodes are transparent, therefore the light beam enters one plate, and exits from the other plate, and is then sent to the screen. In the so-called "reflection-type" devices, which generally
consist of LCoS devices, one plate is transparent and the other one is reflective, so that the light beam goes through the transparent plate, is reflected by the reflective plate, goes through ' the transparent plate again and is finally sent to the screen.
The set of pixels represents the active surface of the panel, on which the image to be projected onto the screen is formed.
Depending on the brightness level required and on the maximum size of the screen, each system of illumination for videoprojector may use one or more devices for the formation of the image, in particular DMD, LCD or LCoS devices; preferably, each system of illumination employs devices of the same type. As to performance and reliability of a system of illumination for videoprojector , the choice of the illuminating device used is of great importance.
Normally, systems of illumination for videoprojector use systems of illumination consisting of arc lamps, which provide a high luminous intensity.
Fig. Ia shows a diagram of a system of illumination for videoprojector according to the prior art. hi the drawing of Fig. Ia, a lamp 1 emits a parallel light beam having a substantially circular section as said lamp 1 is provided with a parabolic shaped reflector.
An aspheric condenser, indicated with reference number 2, sends said light beam to an integrating bar 3, consisting of a parallelepiped made of optical-glass having an inlet face 4 and an outlet face 5,which allows to uniform the light beam exiting from the aspheric condenser 2.
More specifically, said aspheric condenser 2 sends a conical light beam, represented by the triangle f-f-f ' in the horizontal projection of Fig. Ia, to the integrating bar 3; said conical light beam is intercepted by the inlet face 4, so as to form a circle having a diameter d on the surface of said inlet face 4. Fig. Ib shows the inlet face 4 of the integrating bar 3 and the circle having a diameter d which indicates the area illuminated by the conical light beam striking said inlet face.
For simplicity's sake, unless otherwise stated, the following description will always refer to a representation of a system of illumination in a horizontal plane, thus referring to angles rather than to angular apertures of a conical light beam.
The angular aperture of the conical light beam, i.e. the angle in the vertex f of the cone, is equal to an angle 2α in the representation of Fig. Ia.
As known, due to the multiple reflections taking place within the integrating bar 3, the outlet
face 5 is evenly illuminated, as shown in the representation of Fig. Ic; in particular, each point of the surface of said outlet face 5 generates a conical light beam having an angular aperture being equal to the angular aperture of the conical light beam striking the inlet face 4. Therefore, the set of light beams generated by said outlet face 5 can be considered to be a single conical light beam whose angular aperture is represented in Fig. Ia) by the angle 2β of a triangle g-g'-g", said angular aperture being equal to the angular aperture of the conical light beam striking the inlet face 4, represented by the angle 2α; this means that 2α=2β. The light beam exiting from the integrating bar 3 is collected by a system of converging lenses 6, known as "relay lenses", and is then sent to means, e.g. a prism system not shown in Fig. Ia, adapted to break up the light beam, according to known techniques, into the three primary monochromatic components it is composed of, in particular the red, green and blue monochromatic components.
Said primary monochromatic components are then directed to the active surface of several devices for the formation of the image, e.g. three DMDs (Digital Micromirror Devices), not shown in the drawings for simplicity's sake.
The angular aperture of the conical light beam entering said integrating bar 3, and thus the angle 2α, is selected so as to use in the appropriate conditions the various components of the system of illumination which convey the light beam to the devices for the formation of the image, thereby maximizing the light transfer. In order to enhance the brightness of the system of illumination for videoprojector shown in Fig. Ia, it is necessary to increase the power of the lamp; this involves a reduction of the average life of said lamp, which is more stressed. Moreover, a higher lamp power causes the entire system of illumination to become hotter and therefore more difficult to cool, thus requiring bulky cooling solutions. An increase in the brightness of a system of illumination for videoprojector may also be obtained by using the known arrangement shown in Fig. 2, which provides the use of two lamps 1 and 1' which, for simplicity's sake, are supposed to be identical. In the representation of Fig. 2, too, both lamps 1, 1' emit a parallel light beam having a substantially circular section, since said lamps 1, 1' are provided with a parabolic shaped reflector; the use of lamps provided with a parabolic shaped reflector requires the use of collimating means, which allow to converge the parallel light beam generated by the lamps. As a result, each of said lamps 1, 1' is associated with a collimating means, in particular an aspheric condenser 2, 2', which allows to converge the light beam into the integrating bar 3.
Each lamp 1, 1' generates a light beam having a magnitude equal to 2α; the angle of incidence of the light beam when it enters the integrating bar 3 is equal to the sum of the angles of the light beams generated by both lamps 1, 1', and therefore its magnitude is equal to 4α. As already mentioned, the angular aperture of the light beam exiting from the integrating bar 3 is equal to the total angular aperture of the light beam entering the integrating bar 3; therefore, the angular aperture of the output light beam is equal to 4β=4α.
It follows that the overall angular aperture 4β of the light beam exiting from the integrating bar 3 turns out to be twice as the angular aperture of the light beam exiting from the integrating bar 3 produced by a single lamp. Fig. 2 clearly shows that, since the angular aperture 4β of the light beam exiting from the integrating bar 3 is wider, in order to intercept a portion as big as possible of the light beam it is necessary to increase the dimensions of the system of converging lenses 6 and of the other means, eg. prisms not shown in the drawings, which allow to convey the light beam to the devices for the formation of the image, e.g. DMD devices. This inevitably leads to increased costs of the components used in the system of illumination. Besides, the components normally used in the systems of illumination known in the art (e.g. devices for the formation of the image, possible polarizers for LCD devices, possible total- reflection TIR prisms, projection lenses, etc.) require the use of light beams having a limited angular aperture. Consequently, if the system of illumination employs a light beam exiting from the integrating bar 3 with a very wide angular aperture, at least a portion of said light beam will not be used. This will lead to a lower brightness level of the whole system of illumination; furthermore, the unused portion of the light beam will scatter in the system of illumination, thus causing a considerable drop in contrast. It follows that the expected brightness increase due to a doubled light source will not be reached in full.
The object of the present invention is to provide a system of illumination using a plurality of lamps which, by overcoming the above drawbacks, allows to manufacture high-brightness and high-contrast videoprojectors without jeopardizing the reliability of the videoprojector itself and at the same time avoiding any increase in the costs of the components used for its production.
In order to achieve said object, the present invention provides a system of illumination having the features described in the annexed claims, which form an integral part of the present description.
Further objects and advantages of the present invention will become apparent from the following detailed description and from the annexed drawings, which are supplied by way of non-limiting example, wherein:
- Figs. Ia3 Ib, Ic show a first system of illumination for videoprojector according to the prior art;
- Fig. 2 shows a second system of illumination for videoprojector according to the prior art;
- Figs. 3a, 3b and 3c show a first embodiment of a system of illumination for videoprojector according to the invention;
- Fig. 4 shows a second embodiment of a system of illumination for videoprojector according to the invention;
- Fig. 5 shows a third embodiment of a system of illumination for videoprojector according to the invention.
Note that the blocks designated with the same reference number in the various drawings perform the same function. Fig. 3a shows a first embodiment of a system of illumination for videoprojector according to the invention; said system of illumination comprises a plurality of lamps. Said plurality of lamps comprises two lamps 1, 1' which, for simplicity's sake, are supposed to be identical; it is clear that the following considerations may be easily extended to a system of illumination comprising more than two lamps, even being different from one another. Each of said lamps 1, 1' emits a parallel light beam having a substantially circular section, in that said lamps 1, 1 ' are provided with a parabolic shaped reflector.
The use of lamps 1, 1' provided with a parabolic shaped reflector requires that each of said lamps 1, I' be associated with a collimating means, in particular an aspheric condenser 2, 2', which allows to converge the parallel light beam generated by the lamps 1, 1'. According to the present invention, the lamps 1, 1' are associated with two transparent deflecting prisms, being in particular of the "wedge" type and preferably small in size, designated with reference numbers 8 and 8' in Fig. 3a; in particular, in the representation of Fig. 3a said transparent deflecting prisms 8, 8' are positioned between the aspheric condensers 2 and 2', respectively, and an integrating bar 3. The transparent deflecting prism 8 deflects the light beams coming from the lamp 1 and from the respective aspheric condenser 2, so that a first external ray 9 undergoes such a deflection as to generate a light ray 9', which strikes an inlet face 4 of the integrating bar 3 at an angle α, i.e. with an angular aperture being equal to half the angular aperture of the light beam entering
said integrating bar 3, shown in Fig. Ia5 when a single lamp 1 is used which lamp is adapted to generate a light beam having an angular aperture equal to 2α.
By sizing the transparent deflecting prism 8 in a proper way, a second external ray 10 of the light beam generated by the lamp 1 is deflected by the transparent deflecting prism 8 so as to undergo a minimum deflection.
Likewise, the transparent deflecting prism 8' deflects the light beam coming from the lamp I1 and from the respective aspheric condenser 2' so that a first external ray 11 undergoes such a deflection as to generate a light ray 11 ' striking said inlet face 4 of the integrating bar 3 at the same aforementioned angle α, whereas a second external ray 12 undergoes a minimum deflection.
The use of the transparent deflecting prisms 8 and 8' allows the light beam produced by the lamps 1 and 1' to strike the inlet face 4 of the integrating bar 3 with an angular aperture being substantially equal to 2α, i.e. equal to that obtained in the representations of Figs. Ia, Ib, Ic when the system of illumination employs just one lamp 1. Fig. 3b shows the inlet face 4 of the integrating bar 3, on which of course two illuminated areas appear, each having a diameter d, instead of a single area as in the representation of Fig. Ib.
Fig. 3c shows an outlet face 5 of the integrating bar 3, which face, due to the multiple reflections taking place within the integrating bar 3, is evenly illuminated. As stated with reference to the representation of the prior-art system of illumination of Fig. 1 a, which uses a single lamp 1, the conical light beam exiting from the integrating bar 3 has an angular aperture being equal to that of the conical light beam entering the integrating bar 3; it follows that, also with reference to the representation of Fig. 3a, the angle 2β turns out to be equal to the angle 2α. The light beam exiting from the integrating bar 3 is collected by a system of converging lenses 6, known in particular as "relay lenses", and is then sent to decompose means, e.g. a prism system not shown in Fig. 3a, adapted to divide the light beam, according to known techniques, into the three red, green and blue primary monochromatic components. Said primary monochromatic components are further directed toward the active surface of devices for the formation of the image, e.g. three DMDs (Digital Micromirror Devices), not shown in the illustrations.
The association between the transparent deflecting prisms 8, 8' and the lamps 1, 1' of the system of illumination for videoprojector thus allows to obtain a light beam produced by said
lamps 1 and 1' whose angular aperture, both at the inlet and at the outlet of the integrating bar 3, is substantially equal to that obtained in systems of illumination using a single lamp 1, as in the example of Fig. Ia.
It follows that, in order to direct the light beam exiting from the integrating bar 3 to the devices for the formation of the image, which for instance may comprise three DMD, LCD or LCoS devices, one may use the same components, in particular "relay lenses" 6 and prisms not shown in the drawings, as those used in systems of illumination for videoprojector using just one lamp 1, thus with no increase in the costs of the components used in the system of illumination. Furthermore,the use of the transparent deflecting prisms 8, 8' also allows to obtain a light beam exiting from the integrating bar 3 having a narrow angular aperture, so as to allow for a full utilization of the whole light beam in the system of illumination for videoprojector according to the present invention, thereby preventing any brightness and contrast reduction phenomena from arising in the entire system of illumination. Furthermore, in the system of illumination according to the present invention it is possible to turn on the lamps 1, 1' at a power being lower than the nominal power, thereby obtaining a longer life of said lamps 1, 1'.
It is clear that the system of illumination for videoprojector according to the present invention may be subject to many variations without departing from the novelty spirit of the inventive idea.
In the embodiment of Fig. 3a, the light beam produced by the lamps 1, 1' is divided, according to a known technique, into the three red, green and blue primary monochromatic components; these are then sent to a plurality of devices for the formation of the image to be projected, e.g. to three different DMD devices. In case the system of illumination for vodeoprojector uses a device for the formation of the image comprising just one DMD, LCD or LCoS device, said system of illumination may advantageously comprise a rotating wheel, also known as colour wheel, designated 13 in Fig. 4 and positioned between the transparent deflecting prisms 8, 8' and the inlet face 4 of the integrating bar 3. As known, said colour wheel 13 is subdivided into at least three sectors, each consisting of a dichroic filter associated with one of the three primary monochromatic components; the rotation of the colour wheel 13 allows the light beam sent by the device for the formation of the image to take on the colour of the three different primary monochromatic components in succession.
Fig. 5 shows a further embodiment of the system of illumination for videoprojector according to the present invention, which comprises a plurality of lamps 14, 14'. Said lamps 14, 14' are provided with an elliptic shaped reflector adapted to generate a conical light beam; as a result, this solution does not require the use of collimating means associated with each of said lamps 14, 14' in order to converge the light beam. Referring to the representation of Fig. 3a, the transparent deflecting prisms 8, 8' are positioned between the lamps 14, 14' and the inlet face 4 of the integrating bar 3.
It is clear that many other variations and applications of the system of illumination described herein by way of example are possible for those skilled in the art, as well as that in the practical realization of the invention the components may have shapes and dimensions being different from those described or be replaced with other technically equivalent elements.
A A A Λ Λ A A
Claims
1. System of illumination for videoprojector comprising:
- a plurality of lamps (1, 1'; 14, 14') adapted to generate a light beam;
- an integrating bar (3), in particular comprising an inlet face (4) and an outlet face (5), which allows to uniform the light beam generated by said plurality of lamps (1, 1'; 14, 14'); - a system of converging lenses (6) adapted to collect the light beam exiting from said integrating bar (3); characterized in that each lamp (1, 1'; 14, 14') of said plurality of lamps (1, 1'; 14, 14') is associated with a transparent deflecting prism (8, 8') which allows to reduce the angular aperture of the light beam generated by said plurality of lamps (1 , 1 ' ; 14, 14').
2. System of illumination for videoprojector according to claim 1, characterized in that said lamps (14, 14') are provided with an elliptic shaped reflector adapted to generate a conical light beam.
3. System of illumination for videoprojectoraccording to the previous claim, characterized in that said transparent deflecting prisms (8, 8') are positioned between said lamps (14, 14') and the inlet face (4) of said integrating bar (3).
4. System of illumination for videoprojectoraccording to claim 1, characterized in that said lamps (1, 1') are provided with a parabolic shaped reflector adapted to generate a parallel light beam having a substantially circular section.
5. System of illumination for videoprojectoraccording to the previous claim, characterized in that it comprises collimating means (2, 2') associated with each of said lamps (1, 1'), preferably aspheric condensers adapted to converge said parallel light beam generated by the lamps (1, 1').
6. System of illumination for videoprojectoraccording to the previous claim, characterized in that said transparent deflecting prisms (8, 8') are positioned between said aspheric condensers
(2, 2') and said integrating bar (3).
7. System of illumination for videoprojectoraccording to claim 1, characterized in that it also comprises:
- means adapted to divide said light beam into the monochromatic components it is composed of;
- a device for the formation of the image, adapted to receive the monochromatic components of said light beam.
8. System of illumination for videoprojectoraccording to claim 7, characterized in that said device for the formation of the image comprises at least one DMD device.
9. System of illumination for videoprojectoraccording to claim 7, characterized in that said device for the formation of the image comprises at least one LCD device.
10. System of illumination for videoprojectoraccording to claim 7, characterized in that said device for the formation of the image comprises at least one LCoS device.
11. System of illumination for videoprojectoraccording to claim 7, characterized in that said means adapted to divide the light beams comprise a colour wheel (13) for decompose the light beam into the monochromatic components it is composed of.
12. System of illumination for videoprojectoraccording to claim 7, characterized in that said means adapted to divide the light beam comprise a plurality of prisms.
13. System of illumination for videoprojectoraccording to one or more previous claims, characterized in that said transparent deflecting prisms (8, 8') are of the type known as "wedge" prism.
A A A A A A A
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT000379A ITTO20050379A1 (en) | 2005-06-01 | 2005-06-01 | ILLUMINATION SYSTEM FOR VIDEOPROJECTOR THAT USES A PLURALITY OF LAMPS |
ITTO2005A000379 | 2005-06-01 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2006129151A1 true WO2006129151A1 (en) | 2006-12-07 |
Family
ID=36808997
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IB2006/001325 WO2006129151A1 (en) | 2005-06-01 | 2006-05-22 | System of illumination for videoprojector using a plurality of lamps |
Country Status (3)
Country | Link |
---|---|
IT (1) | ITTO20050379A1 (en) |
TW (1) | TW200702888A (en) |
WO (1) | WO2006129151A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102645275A (en) * | 2012-05-04 | 2012-08-22 | 中国计量科学研究院 | Device capable of producing contrast observation object and chromatic aberration observation object |
CN102657510A (en) * | 2012-05-04 | 2012-09-12 | 中国计量科学研究院 | Device for generating observation target with illumination and color |
CN103308172A (en) * | 2012-12-26 | 2013-09-18 | 中国计量科学研究院 | Device and method for measuring visual threshold values |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5619284A (en) * | 1995-01-17 | 1997-04-08 | Philips Electronics North America Corporation | Beam combiner for LCD projector utilizing a penta-prism |
JPH11119149A (en) * | 1997-10-17 | 1999-04-30 | Matsushita Electric Ind Co Ltd | Liquid crystal projection device |
WO2004107018A1 (en) * | 2003-06-02 | 2004-12-09 | Koninklijke Philips Electronics N.V. | Led illumination system |
US20050046981A1 (en) * | 2003-08-25 | 2005-03-03 | Nec Viewtechnology, Inc. | Color projection type display apparatus reusing incident light |
-
2005
- 2005-06-01 IT IT000379A patent/ITTO20050379A1/en unknown
-
2006
- 2006-05-11 TW TW095116807A patent/TW200702888A/en unknown
- 2006-05-22 WO PCT/IB2006/001325 patent/WO2006129151A1/en active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5619284A (en) * | 1995-01-17 | 1997-04-08 | Philips Electronics North America Corporation | Beam combiner for LCD projector utilizing a penta-prism |
JPH11119149A (en) * | 1997-10-17 | 1999-04-30 | Matsushita Electric Ind Co Ltd | Liquid crystal projection device |
WO2004107018A1 (en) * | 2003-06-02 | 2004-12-09 | Koninklijke Philips Electronics N.V. | Led illumination system |
US20050046981A1 (en) * | 2003-08-25 | 2005-03-03 | Nec Viewtechnology, Inc. | Color projection type display apparatus reusing incident light |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 1999, no. 09 30 July 1999 (1999-07-30) * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102645275A (en) * | 2012-05-04 | 2012-08-22 | 中国计量科学研究院 | Device capable of producing contrast observation object and chromatic aberration observation object |
CN102657510A (en) * | 2012-05-04 | 2012-09-12 | 中国计量科学研究院 | Device for generating observation target with illumination and color |
CN103308172A (en) * | 2012-12-26 | 2013-09-18 | 中国计量科学研究院 | Device and method for measuring visual threshold values |
Also Published As
Publication number | Publication date |
---|---|
ITTO20050379A1 (en) | 2006-12-02 |
TW200702888A (en) | 2007-01-16 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6343862B1 (en) | Projecting image display device | |
JP6744041B2 (en) | Light source device, projector and speckle reduction method | |
JP7482351B2 (en) | Light source device and projection type image display device | |
JP5605047B2 (en) | Light source device and projection display device using the same | |
JP4091632B2 (en) | Projection display optical system and projector including the projection display optical system | |
KR100677551B1 (en) | LED package, illumination system and projection system employing the LED package | |
JP2004258666A (en) | Projection display optical system | |
JPH10333115A (en) | Projection type liquid crystal display device | |
US11099468B2 (en) | Light source device and projection display apparatus | |
US7055959B2 (en) | Projection display device and back projection display device using the display device | |
US20050185148A1 (en) | Sequential color recapture for image display systems | |
KR100549136B1 (en) | Projection type image display apparatus | |
US10845578B2 (en) | Light source device and projection display apparatus | |
US6799852B2 (en) | Image display projector | |
WO2006129151A1 (en) | System of illumination for videoprojector using a plurality of lamps | |
JP2019132986A (en) | Illumination device and projection-type video display device | |
JP2003149597A (en) | Display unit | |
EP1627527A1 (en) | Illumination system for videoprojector utilizing one or more led diodes matrices | |
JP7342624B2 (en) | Light source device, image projection device, and light source optical system | |
JP2004053655A (en) | Polarizing optical system and projector | |
US20090040395A1 (en) | Image display apparatus | |
KR100590327B1 (en) | Optical unit using of digital micromirror | |
KR100595196B1 (en) | Optical Device | |
JP2023051736A (en) | Light source device, image projection device, and display device | |
KR100219640B1 (en) | Lcd projector |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
NENP | Non-entry into the national phase |
Ref country code: DE |
|
WWW | Wipo information: withdrawn in national office |
Country of ref document: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 06744737 Country of ref document: EP Kind code of ref document: A1 |