US20010000056A1 - Projection type liquid crystal display device - Google Patents
Projection type liquid crystal display device Download PDFInfo
- Publication number
- US20010000056A1 US20010000056A1 US09/727,541 US72754100A US2001000056A1 US 20010000056 A1 US20010000056 A1 US 20010000056A1 US 72754100 A US72754100 A US 72754100A US 2001000056 A1 US2001000056 A1 US 2001000056A1
- Authority
- US
- United States
- Prior art keywords
- liquid crystal
- crystal display
- light
- display device
- lens array
- Prior art date
- Legal status (The legal status 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 status listed.)
- Granted
Links
- 239000004973 liquid crystal related substance Substances 0.000 title claims abstract description 85
- 238000005286 illumination Methods 0.000 claims abstract description 33
- 230000003287 optical effect Effects 0.000 claims abstract description 21
- 230000001678 irradiating effect Effects 0.000 claims abstract description 6
- 239000004411 aluminium Substances 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 238000001704 evaporation Methods 0.000 claims description 2
- 230000008020 evaporation Effects 0.000 claims description 2
- 238000010276 construction Methods 0.000 description 16
- 238000010586 diagram Methods 0.000 description 11
- 230000003247 decreasing effect Effects 0.000 description 6
- 230000010287 polarization Effects 0.000 description 6
- 238000004513 sizing Methods 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 5
- 239000003086 colorant Substances 0.000 description 3
- 230000004907 flux Effects 0.000 description 3
- 229910001507 metal halide Inorganic materials 0.000 description 3
- 150000005309 metal halides Chemical class 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005693 optoelectronics Effects 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 210000002858 crystal cell Anatomy 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- 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]
-
- 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
-
- 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
- G02B27/0927—Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat
-
- 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
- G02B27/0955—Lenses
- G02B27/0961—Lens arrays
-
- 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
- G02B27/0977—Reflective elements
- G02B27/0983—Reflective elements being curved
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/74—Projection arrangements for image reproduction, e.g. using eidophor
- H04N5/7416—Projection arrangements for image reproduction, e.g. using eidophor involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal
- H04N5/7441—Projection arrangements for image reproduction, e.g. using eidophor involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal the modulator being an array of liquid crystal cells
-
- 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]
- H04N9/3102—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators
- H04N9/3105—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators
Definitions
- the present Invention relates to a projection type liquid crystal display device using liquid crystal display elements, and in particular to a projection type liquid crystal display device having a small size and a good image quality performance such as brightness, etc.
- an image display device there is known a projection type display device, in which an optical image formed on light valves as variations in optical characteristics, depending on image signals, is illuminated by means of illumination optics to be enlarged and projected on a screen by means of projection optics.
- a number of projection type liquid crystal display devices have been proposed, each of which uses liquid crystal display elements as light valves for such a display device.
- a twisted nematic (TN) type liquid crystal display element which is a representative example of a liquid crystal display element, is so constructed that two polarizers are disposed before and after a liquid crystal cell, in which liquid crystal is injected between a pair of transparent base plates, each of which has a transparent electrode film, so that polarization directions thereof differ by 90° from each other and a number of such liquid crystal display elements are arranged so that light intensity of incident light transmitted by each of them is controlled by combining an action to rotate a polarization plane by an electro-optical effect of the liquid crystal with an action to select a polarization component by one of the polarizers to display image information. Recently performance such as resolution, etc.
- a main object of the present invention is to provide a projection type liquid crystal display device having a small size and a good image quality performance.
- Another object of the present invention is to raise utilization efficiency of light emitted from a light source.
- Still another object of the present invention is to make brightness uniform over a whole screen.
- FIG. 1 is a diagram showing the construction of an optical system in a projection type liquid crystal display device according to the present invention
- FIG. 2 is a cross-sectional diagram showing the principle of an action of a part of illumination optics in FIG. 1;
- FIG. 3 is a diagram showing the construction of an embodiment of a light source used in FIG. 1;
- FIG. 4 is a cross-sectional diagram showing the principle of illumination optics used in FIG. 1;
- FIG. 5 is a cross-sectional view and a side view showing an example of the shape of a first lens array used in FIG. 1;
- FIG. 6 is a cross-sectional view and a side view showing an example of the shape of a second lens array used in FIG. 1;
- FIG. 7 is a diagram showing the construction of an embodiment of a projection type liquid crystal display device according to the present invention.
- FIG. 9 is a diagram showing another embodiment of a condenser lens in FIG. 1.
- FIG. 1 is a diagram showing the construction of an optical system in a projection type liquid crystal display device according to the present invention.
- a light source 1 is an incandescent lamp such as a metal halide lamp, xenon lamp, halogen lamp, etc.
- illumination optics consisting of the light source 1 , an elliptic mirror 5 and a spherical mirror 6 , light emitted by the light source 1 is reflected by the elliptic mirror 5 and the spherical mirror 6 .
- After having passed through a first lens array 22 it passes through a second lens array 23 and enters a condenser lens 7 .
- the condenser lens 7 has a positive reflective power and an action to focus further light emitted by the illumination optics 2 .
- Light, which has passed through the condenser lens 7 irradiates liquid crystal display elements 3 .
- Light, which has passed through the liquid crystal display elements 3 enters a field lens 8 having an action to have the light enter projection optics 4 , which are e.g. a zoom lens. Thereafter it passes through the projection optics 4 to reach a screen 9 .
- An image formed on the liquid crystal display elements 3 by the field lens 8 and the projection optics 4 is enlarged to be projected on the screen 9 .
- the whole device functions as a display device.
- FIG. 2 is a cross-sectional diagram showing the principle of an action of a part of illumination optics in the projection type liquid crystal display device according to the present invention, which shows an aspect, in which light emitted by the light source is reflected by the elliptic mirror 5 and the spherical mirror 6 .
- the light B 2 is light, which didn't reach heretofore the surface to be irradiated such as liquid crystal display elements, and therefore it is possible to raise the light utilization efficiency by arranging the liquid crystal display elements in the neighborhood of the point P′ in the construction indicated in FIG. 2. Further, if it is tried to raise the light utilization efficiency by using only one reflecting mirror such as the elliptic mirror 5 without spherical mirror 6 as in prior art illumination optics, problems are produced that the size of reflecting mirror is increased or that a projection lens having a small F number as projecting means is required, accompanied therewith, which enlarges the size of the projection lens.
- FIG. 3 is a diagram showing the construction of an example of the light source 1 in the projection type liquid crystal display device according to the present invention, which is a construction where the light source consists in a lamp 10 .
- reference numeral 13 is a light emitting bulb made of quartz glass, etc., in which gas is enclosed for having it act as a device for igniting a metal vapor discharge bulb including mercury, argon, etc.
- reference numeral 11 is an electrode; 12 is a reflective layer; 15 is a molybdenum foil having functions to maintain air-tightness of the light emitting bulb 13 , etc.; 14 is lead wire; and 16 is a base. Light is emitted from a lighting point 17 by discharge between a pair of electrodes 11 .
- the reflective layer 12 is made of zirconia, etc.
- the reflective layer 12 is disposed only in a region in accordance with the shape of the spherical mirror. That is, the shape of the reflective layer is so determined that the light B emitted by the lighting point 17 indicated in FIG.
- the spherical mirror 6 has a function identical to that of the prior art reflective layer. Consequently it is possible to obtain illumination optics having a high light utilization efficiency by combining the the reflecting mirror construction indicated in FIG. 2 with the lamp indicated in FIG. 3, owing to mutual reactions thereof, without worsening the light emitting property, the life time, etc. of the lamp, even if the area where the reflective layer is applied is decreased.
- FIG. 4 is a cross-sectional view showing the principle of the action of the lens arrays in the illumination optics according to the present invention.
- the first lens array 22 In the illumination optics indicated in FIG. 4, light emitted from the light source 1 enters the first lens array 22 to be focused on the second lens array 23 . After having passed through the second lens array, it enters the condenser lens 7 to irradiate the liquid crystal display elements 3 . At that time, the first lens array 22 is so set that the image of the lighting point of the light source 1 is focused at the position of the second lens array 23 . In this way, the light flux passing through the second lens array 23 is made narrow and as the result the first lens array 22 has a function to increase the ratio of the amount of light passing through the second lens array 23 .
- the second lens array 23 has a same number of lenses (18 in the embodiment of the present invention) as the first lens array 22 , each lens of the former corresponding to the respective lens of the latter, and each lens of the second lens array 23 has a function to focus a rectangular aperture figure of a corresponding lens of the first lens array 22 on the liquid crystal display elements 3 .
- the shape of light irradiating the liquid crystal display elements 3 is rectangular and it is possible to realize an image, which is bright in the whole, and easy to see, in which brightness uniformity is high.
- FIG. 5 shows an example of the shape of the first lens array 22 according to the present invention.
- each of the lenses constituting the first lens array 22 is rectangular and thus it is possible to irradiate the liquid crystal display elements 3 with light spots, each of which is rectangular. Further, each of black points indicated in FIG. 5 represents an optical axis of each of the lenses constituting the first lens array 22 .
- the position of the light focused on the second lens array 23 by the first lens array 22 can be controlled by the fact that the optical axis of each lens is shifted from the geometrical center of the rectangular shape and in this way it is possible to increase the amount of light passing through the second lens array 23 while decreasing the size of the second lens array 23 by setting the optical axis at the optimum position.
- FIG. 6 shows an example of the shape of the second lens array 23 according to the present invention.
- the second lens array 23 is constructed by lenses, each of which has an aperture figure quadrilateral or pentagonal.
- the cross section of the lighting point is usually approximately elliptic and as the result, the image of the lighting point of the light source on the second lens array 23 formed by the first lens array 22 is approximately elliptic.
- the lenses constituting the second lens array 23 are rectangular, there exist many portions, for which light transmittance is low, i.e. dead spaces, which gives rise to a problem that the second lens array 23 should be large or that light utilization efficiency is low.
- the dead spaces are decreased and illumination optics having a high light utilization efficiency can be obtained while keeping the small size of the whole device.
- FIG. 7 is a diagram showing an embodiment of the projection type liquid crystal display device according to the present invention.
- the embodiment indicated in FIG. 7 shows a three plate projection type liquid crystal display device using 3 plates in total, in which transmission type liquid crystal display elements acting as liquid crystal light valves correspond to three colors, which are the three primary colors, i.e. R (red), G (green) and B (blue).
- a lamp 10 serving as the light source which is e.g. a metal halide lamp, enters the first lens array 22 after having been reflected by the elliptic mirror 5 or the spherical mirror 6 .
- Light, which has passed through the first lens array 22 passes through the second lens array 23 .
- An R light beam exiting from the field lens 8 R passes through a dichroic mirror 26 having a function of making the R light beam pass through to enter projection optics 4 such as e.g. a zoom lens after having been reflected by a dichroic mirror 27 having a function of reflecting the R light beam and the B light beam.
- the G light beam and the B light beam reflected by the R transmission dichroic mirror 24 enters a B reflection dichroic mirror 25 .
- the B light beam is reflected by the mirror passes through a condenser lens 7 B and an incident side polarizer 20 B to enter liquid crystal display elements 3 B and passes through an exit side polarizer 21 B and a field lens 8 B disposed on the light exit side of the liquid crystal display elements 3 B.
- the B light beam exiting from the field lens 8 B is reflected by the dichroic mirror 26 having a function of reflecting the B light beam to enter the projection optics 4 after having been reflected by the dichroic mirror 27 together with the R light beam.
- the G light beam which has passed through a dichroic mirror 25 , passes through a condenser lens 7 G and an incident side polarizer 20 G to enter liquid crystal display elements 3 G and passes through an exit side polarizer 21 G and a field lens 8 G disposed on the light exit side of the liquid crystal display elements 3 G.
- the G light beam exiting from the field lens 8 G is reflected by a reflective mirror 28 to enter the projection optics 28 after having been transmitted by the dichroic mirror 27 together with the R light beam and the B light beam.
- the light beams corresponding to R, G and B are separated and combined by color separation optics and color combination optics and the projection optics 4 enlarge an image on the liquid crystal display elements corresponding to R, G and B to obtain a real image by combining and enlarging the images of the different colors on a screen.
- 30 is a housing; 31 is a speaker; 32 is a power supply circuit; and 43 is an image signal circuit.
- Further 33 is a blowoff duct having a function of conducting wind from a case 19 , etc. for the illumination optics 2 to a blowoff fan 34 .
- the speaker 31 gives users voice information parallelly to image information.
- the size of the whole device is decreased and the shape thereof is rectangular by arranging the illumination optics 2 and the projection optics 4 so that optical axes thereof are parallel to each other and further by arranging the power supply circuit 32 and the image signal circuit 42 through a color separation and combination unit 44 consisting of the color separation optics, the liquid crystal display elements and the color combination optics, as indicated in the figure.
- a color separation and combination unit 44 consisting of the color separation optics, the liquid crystal display elements and the color combination optics, as indicated in the figure.
- the lamp 10 in the present embodiment is a metal halide lamp as indicated e.g. in FIG. 3.
- the functions of the illumination optics including the lamp are as described previously and explanation thereof is omitted here.
- the liquid crystal display elements e.g. 3 R
- the incident side polarizer 20 R which is a polarizer transmitting linearly polarized light
- the exit side polarizer 21 R which is a polarizer transmitting linearly polarized light having a polarization plane, rotated by 90° with respect to the incident side polarizer 20 R.
- Image information is displayed by controlling the transmitted amount of incident light while combining the function of rotating the polarization plane by the electro-optical effect of liquid crystal in the liquid crystal display elements 3 R with the function of selecting a polarization component of the incident side polarizer 20 R and the exit side polarizer 21 R serving as polarizers. It can be said that this is identical for B and R.
- FIG. 7 represents a case for the illumination optics 2 .
- the lamp can be exchanged by exchanging the case 19 whole.
- a concrete example of display means having such a construction will be explained, referring to FIG. 8.
- FIG. 8 is a cross-sectional view showing the construction of a concrete example of display means applied to the projection type liquid crystal display device according to the present invention.
- the example indicated in FIG. 8 is so constructed that the elliptic mirror 5 and the spherical mirror 6 are arranged, through a holding reflective mirror plate 36 . In this way the elliptic mirror 5 and the spherical mirror 6 can be located precisely. Particularly, in case where small size liquid crystal display elements are used, and further in case where the light utilization efficiency is high, since positional precision for the elliptic mirror 5 and the spherical mirror 6 , etc. is severe, it is efficient to arrange them through a member. Further the example indicated in FIG. 8 is so constructed that the holding plate 36 is put between other members 35 and 37 and in this way mounting work at fabrication can be effected easily.
- the construction according to the present invention it is useful for increasing in brightness uniformity over the whole screen, light utilization efficiency, etc. to have either one or a plurality of the elliptic mirror 5 , the spherical mirror 6 , the first lens array 22 , the second lens array 23 , the condenser lens 7 and the field lens 8 have a shape varied at the peripheral portion with respect to the portion near the optical axis.
- the ratio of the brightness at the peripheral portion to the brightness at the central portion can be increased further, which improves brightness uniformity over the whole screen.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Nonlinear Science (AREA)
- Liquid Crystal (AREA)
- Mathematical Physics (AREA)
- Projection Apparatus (AREA)
- Devices For Indicating Variable Information By Combining Individual Elements (AREA)
- Transforming Electric Information Into Light Information (AREA)
Abstract
Description
- 1. The present Invention relates to a projection type liquid crystal display device using liquid crystal display elements, and in particular to a projection type liquid crystal display device having a small size and a good image quality performance such as brightness, etc.
- 2. Heretofore, as an image display device, there is known a projection type display device, in which an optical image formed on light valves as variations in optical characteristics, depending on image signals, is illuminated by means of illumination optics to be enlarged and projected on a screen by means of projection optics. A number of projection type liquid crystal display devices have been proposed, each of which uses liquid crystal display elements as light valves for such a display device. A twisted nematic (TN) type liquid crystal display element, which is a representative example of a liquid crystal display element, is so constructed that two polarizers are disposed before and after a liquid crystal cell, in which liquid crystal is injected between a pair of transparent base plates, each of which has a transparent electrode film, so that polarization directions thereof differ by 90° from each other and a number of such liquid crystal display elements are arranged so that light intensity of incident light transmitted by each of them is controlled by combining an action to rotate a polarization plane by an electro-optical effect of the liquid crystal with an action to select a polarization component by one of the polarizers to display image information. Recently performance such as resolution, etc. is rapidly improved as down-sizing of such transmission type or reflection type liquid crystal display elements themselves is advanced so that down-sizing and improvement in performance of a display device using such liquid crystal display elements are advanced. In this way, projection type liquid crystal display devices have been newly proposed not only for conventional image display using video signals, etc. but also for image output devices of personal computers.
- 3. However a prior art projection type liquid crystal display device had problems that it has a large size and that performance such as brightness of image, etc. finally obtained is insufficient. Although down-sizing of light valves, i.e. liquid crystal display elements themselves, is efficient for down-sizing of a whole display device, since an area illuminated by illumination optics is decreased, when the size of liquid crystal display elements is decreased, problems take place that a ratio of a light flux projected on liquid crystal display elements to a whole light flux emitted by a light source (hereinbelow called light utilization efficiency) is lowered, etc. As the result, it was difficult to realize down-sizing of the whole device and improvement of performance such as brightness, etc. at the same time. Further, in case of a projection type liquid crystal display device, since various factors such as optical characteristics of a projection lens, optical characteristics of liquid crystal display elements, etc. apart from the illumination optics have influences on image quality performance, it was difficult to obtain a display device having a small size and a good image quality performance, if only the illumination optics were improved.
- 4. A main object of the present invention is to provide a projection type liquid crystal display device having a small size and a good image quality performance.
- 5. Another object of the present invention is to raise utilization efficiency of light emitted from a light source.
- 6. Still another object of the present invention is to make brightness uniform over a whole screen.
- 7. According to the present invention, a projection type liquid crystal display device, which includes a light source; illumination optics having an action to irradiate a surface to be irradiated with light emitted by the light source; liquid crystal display elements modulating light; and projection optics for projecting light emitted by the liquid crystal display elements, is so constructed that the illumination optics have at least one elliptic mirror and one spherical mirror and that the illumination optics comprise further a first lens array and a second lens array, in which a plurality of lenses are arranged perpendicularly to an optical axis from the light source side, and a condenser lens for irradiating the liquid crystal display elements with light, which has been emitted by the second lens array, with a high efficiency.
- 8. In this way, it is possible to realize a bright projection type liquid crystal display device having a small size and a good image quality performance by raising utilization efficiency of light emitted by the light source.
- 9. Preferred embodiments of the present invention will now be described in conjunction with the accompanying drawings, in which;
- 10.FIG. 1 is a diagram showing the construction of an optical system in a projection type liquid crystal display device according to the present invention;
- 11.FIG. 2 is a cross-sectional diagram showing the principle of an action of a part of illumination optics in FIG. 1;
- 12.FIG. 3 is a diagram showing the construction of an embodiment of a light source used in FIG. 1;
- 13.FIG. 4 is a cross-sectional diagram showing the principle of illumination optics used in FIG. 1;
- 14.FIG. 5 is a cross-sectional view and a side view showing an example of the shape of a first lens array used in FIG. 1;
- 15.FIG. 6 is a cross-sectional view and a side view showing an example of the shape of a second lens array used in FIG. 1;
- 16.FIG. 7 is a diagram showing the construction of an embodiment of a projection type liquid crystal display device according to the present invention;
- 17.FIG. 8 is a diagram showing the construction of a concrete example of illumination optics used in the projection type liquid crystal display device according to the present invention; and
- 18.FIG. 9 is a diagram showing another embodiment of a condenser lens in FIG. 1.
- 19. Several embodiments of the present invention will be explained below, referring the drawings.
- 20.FIG. 1 is a diagram showing the construction of an optical system in a projection type liquid crystal display device according to the present invention. In FIG. 1, a
light source 1 is an incandescent lamp such as a metal halide lamp, xenon lamp, halogen lamp, etc. In illumination optics consisting of thelight source 1, anelliptic mirror 5 and aspherical mirror 6, light emitted by thelight source 1 is reflected by theelliptic mirror 5 and thespherical mirror 6. After having passed through afirst lens array 22, it passes through asecond lens array 23 and enters acondenser lens 7. Thecondenser lens 7 has a positive reflective power and an action to focus further light emitted by theillumination optics 2. Light, which has passed through thecondenser lens 7, irradiates liquidcrystal display elements 3. Light, which has passed through the liquidcrystal display elements 3, enters a field lens 8 having an action to have the lightenter projection optics 4, which are e.g. a zoom lens. Thereafter it passes through theprojection optics 4 to reach a screen 9. An image formed on the liquidcrystal display elements 3 by the field lens 8 and theprojection optics 4 is enlarged to be projected on the screen 9. Thus the whole device functions as a display device. - 21. Next functions of principal parts of the projection type liquid crystal display device according to the present invention will be explained in detail. FIG. 2 is a cross-sectional diagram showing the principle of an action of a part of illumination optics in the projection type liquid crystal display device according to the present invention, which shows an aspect, in which light emitted by the light source is reflected by the
elliptic mirror 5 and thespherical mirror 6. - 22. A point P and another point P′ indicated in FIG. 2 indicate positions of the first and the second focal point, respectively, of an elliptic surface, which is a reflecting surface of the elliptic mirror. Light B1 exiting from the point P towards the
elliptic mirror 5 is reflected by theelliptic mirror 5 and arrives at the point P′ on anoptical axis 18. Consequently all the light exiting from the point P and reflected directly by theelliptic mirror 5 reaches the point P′. On the other hand, in case where the center of a spherical surface, which is a reflecting surface of the spherical mirror, is in accordance with the point P, light B2 exiting from the position of the point P towards thespherical mirror 6 is reflected by thespherical mirror 6 to return again to the point P and to proceed to theelliptic mirror 5 and reaches the point P′ after having been reflected by theelliptic mirror 5. By these actions, in the light exiting from the position of the point P, in principle all the light entering theelliptic mirror 5 or thespherical mirror 6 reaches the point P′. The light B2 is light, which didn't reach heretofore the surface to be irradiated such as liquid crystal display elements, and therefore it is possible to raise the light utilization efficiency by arranging the liquid crystal display elements in the neighborhood of the point P′ in the construction indicated in FIG. 2. Further, if it is tried to raise the light utilization efficiency by using only one reflecting mirror such as theelliptic mirror 5 withoutspherical mirror 6 as in prior art illumination optics, problems are produced that the size of reflecting mirror is increased or that a projection lens having a small F number as projecting means is required, accompanied therewith, which enlarges the size of the projection lens. - 23.FIG. 3 is a diagram showing the construction of an example of the
light source 1 in the projection type liquid crystal display device according to the present invention, which is a construction where the light source consists in alamp 10. - 24. In FIG. 3,
reference numeral 13 is a light emitting bulb made of quartz glass, etc., in which gas is enclosed for having it act as a device for igniting a metal vapor discharge bulb including mercury, argon, etc. In FIG. 3,reference numeral 11 is an electrode; 12 is a reflective layer; 15 is a molybdenum foil having functions to maintain air-tightness of thelight emitting bulb 13, etc.; 14 is lead wire; and 16 is a base. Light is emitted from alighting point 17 by discharge between a pair ofelectrodes 11. Here thereflective layer 12 is made of zirconia, etc. and has functions to maintain temperature of the light emitting bulb, to increase vapor pressure, etc., which gives rise to an effect that a satisfactory continuous light emitting property or a long life time of lamp can be obtained. However, since in the light emitted by thelighting point 17 light entering thereflective layer 12 was absorbed or diffused and reflected, illumination optics using a prior art lamp, in which the reflective layer was applied over a wide region, had a bad light utilization efficiency. In case where a lamp having the construction indicated in FIG. 3 according to the present invention is used, thereflective layer 12 is disposed only in a region in accordance with the shape of the spherical mirror. That is, the shape of the reflective layer is so determined that the light B emitted by thelighting point 17 indicated in FIG. 3 enters thespherical mirror 6 indicated in FIG. 2 without being absorbed or reflected by thereflective layer 12. In this way, by using illumination optics consisting of thelamp 10 and the construction indicated in FIG. 2 in combination, it is possible to use light, which was heretofore absorbed or diffused and reflected by thereflective layer 12, for irradiation with a high efficiency, which raises the light utilization efficiency. On the other hand, in case where a lamp is disposed so that thelighting point 17 is positioned in the neighborhood of the point P in FIG. 2, as described above, light emitted by thelighting point 17 and entering thespherical mirror 6 is reflected to return again towards the lighting point. For this reason, light reflected by thespherical mirror 6 is projected to thelight emitting bulb 13 in the lamp, which has effects that the temperature of the light emitting bulb is maintained, that the vapor pressure is raised, etc. That is, thespherical mirror 6 has a function identical to that of the prior art reflective layer. Consequently it is possible to obtain illumination optics having a high light utilization efficiency by combining the the reflecting mirror construction indicated in FIG. 2 with the lamp indicated in FIG. 3, owing to mutual reactions thereof, without worsening the light emitting property, the life time, etc. of the lamp, even if the area where the reflective layer is applied is decreased. - 25. In addition, in the construction according to the present invention, in case where the efficiency to return light from the
spherical mirror 6 to the lamp is high and further a satisfactory light emitting performance, a long life time, etc. can be obtained, thereflective layer 12 may be omitted. In order to have thespherical mirror 6 have satisfactorily the function of the prior artreflective layer 12, it is preferable to form a reflecting film on the reflecting surface of thespherical mirror 6 by aluminium evaporation, etc. rather than to construct it by a dichroic mirror which reflects only visible light. - 26. Next functions of the first and the second lens array according to the present invention will be explained, referring to FIG. 4.
- 27.FIG. 4 is a cross-sectional view showing the principle of the action of the lens arrays in the illumination optics according to the present invention.
- 28. In the illumination optics indicated in FIG. 4, light emitted from the
light source 1 enters thefirst lens array 22 to be focused on thesecond lens array 23. After having passed through the second lens array, it enters thecondenser lens 7 to irradiate the liquidcrystal display elements 3. At that time, thefirst lens array 22 is so set that the image of the lighting point of thelight source 1 is focused at the position of thesecond lens array 23. In this way, the light flux passing through thesecond lens array 23 is made narrow and as the result thefirst lens array 22 has a function to increase the ratio of the amount of light passing through thesecond lens array 23. - 29. Further the
second lens array 23 has a same number of lenses (18 in the embodiment of the present invention) as thefirst lens array 22, each lens of the former corresponding to the respective lens of the latter, and each lens of thesecond lens array 23 has a function to focus a rectangular aperture figure of a corresponding lens of thefirst lens array 22 on the liquidcrystal display elements 3. As the result, the shape of light irradiating the liquidcrystal display elements 3 is rectangular and it is possible to realize an image, which is bright in the whole, and easy to see, in which brightness uniformity is high. - 30.FIG. 5 shows an example of the shape of the
first lens array 22 according to the present invention. - 31. As indicated in FIG. 5, the shape of each of the lenses constituting the
first lens array 22 is rectangular and thus it is possible to irradiate the liquidcrystal display elements 3 with light spots, each of which is rectangular. Further, each of black points indicated in FIG. 5 represents an optical axis of each of the lenses constituting thefirst lens array 22. The position of the light focused on thesecond lens array 23 by thefirst lens array 22 can be controlled by the fact that the optical axis of each lens is shifted from the geometrical center of the rectangular shape and in this way it is possible to increase the amount of light passing through thesecond lens array 23 while decreasing the size of thesecond lens array 23 by setting the optical axis at the optimum position. - 32.FIG. 6 shows an example of the shape of the
second lens array 23 according to the present invention. - 33. As indicated in FIG. 6, the
second lens array 23 according to the present invention is constructed by lenses, each of which has an aperture figure quadrilateral or pentagonal. In case where a lamp as indicated in FIG. 3 is used as a light source, the cross section of the lighting point is usually approximately elliptic and as the result, the image of the lighting point of the light source on thesecond lens array 23 formed by thefirst lens array 22 is approximately elliptic. For this reason, if the lenses constituting thesecond lens array 23 are rectangular, there exist many portions, for which light transmittance is low, i.e. dead spaces, which gives rise to a problem that thesecond lens array 23 should be large or that light utilization efficiency is low. According to the present invention, owing to the fact that the aperture figure of the lenses of thesecond lens array 23 is quadrilateral or pentagonal, as indicated in FIG. 6, the dead spaces are decreased and illumination optics having a high light utilization efficiency can be obtained while keeping the small size of the whole device. - 34. Owing to the functions described above, by using small liquid crystal display elements, it is possible to realize a bright liquid crystal display device having an image, which is uniform over a whole screen, and a good image quality performance, even if the whole display device is small.
- 35. Next a concrete whole construction of the projection type liquid crystal display device according to the present invention will be explained.
- 36.FIG. 7 is a diagram showing an embodiment of the projection type liquid crystal display device according to the present invention.
- 37. The embodiment indicated in FIG. 7 shows a three plate projection type liquid crystal display device using 3 plates in total, in which transmission type liquid crystal display elements acting as liquid crystal light valves correspond to three colors, which are the three primary colors, i.e. R (red), G (green) and B (blue). In the present embodiment, light emitted by a
lamp 10 serving as the light source, which is e.g. a metal halide lamp, enters thefirst lens array 22 after having been reflected by theelliptic mirror 5 or thespherical mirror 6. Light, which has passed through thefirst lens array 22, passes through thesecond lens array 23. Thereafter light of G (green) and B (blue) is reflected by an R (red) transmission dichroic mirror arranged at an angle 45° with respect to the optical axis and light of R (red) is transmitted therethrough. The optical path of a reflected R light beam is bent by areflective mirror 29, passes through acondenser lens 7R and an incident side polarizer 20R to enter liquidcrystal display elements 3R constructed by a counter-electrode, liquid crystals, etc. and passes through anexit side polarizer 21R and afield lens 8R disposed on the light exit side of the liquidcrystal display elements 3R. An R light beam exiting from thefield lens 8R passes through adichroic mirror 26 having a function of making the R light beam pass through to enterprojection optics 4 such as e.g. a zoom lens after having been reflected by adichroic mirror 27 having a function of reflecting the R light beam and the B light beam. On the other hand the G light beam and the B light beam reflected by the R transmissiondichroic mirror 24 enters a B reflectiondichroic mirror 25. The B light beam is reflected by the mirror passes through acondenser lens 7B and an incident side polarizer 20B to enter liquidcrystal display elements 3B and passes through anexit side polarizer 21B and afield lens 8B disposed on the light exit side of the liquidcrystal display elements 3B. The B light beam exiting from thefield lens 8B is reflected by thedichroic mirror 26 having a function of reflecting the B light beam to enter theprojection optics 4 after having been reflected by thedichroic mirror 27 together with the R light beam. - 38. On the other hand, the G light beam, which has passed through a
dichroic mirror 25, passes through acondenser lens 7G and an incident side polarizer 20G to enter liquidcrystal display elements 3G and passes through anexit side polarizer 21G and a field lens 8G disposed on the light exit side of the liquidcrystal display elements 3G. - 39. The G light beam exiting from the field lens 8G is reflected by a
reflective mirror 28 to enter theprojection optics 28 after having been transmitted by thedichroic mirror 27 together with the R light beam and the B light beam. In this way, the light beams corresponding to R, G and B are separated and combined by color separation optics and color combination optics and theprojection optics 4 enlarge an image on the liquid crystal display elements corresponding to R, G and B to obtain a real image by combining and enlarging the images of the different colors on a screen. In FIG. 7, 30 is a housing; 31 is a speaker; 32 is a power supply circuit; and 43 is an image signal circuit. Further 33 is a blowoff duct having a function of conducting wind from acase 19, etc. for theillumination optics 2 to ablowoff fan 34. Further thespeaker 31 gives users voice information parallelly to image information. - 40. The size of the whole device is decreased and the shape thereof is rectangular by arranging the
illumination optics 2 and theprojection optics 4 so that optical axes thereof are parallel to each other and further by arranging thepower supply circuit 32 and the image signal circuit 42 through a color separation andcombination unit 44 consisting of the color separation optics, the liquid crystal display elements and the color combination optics, as indicated in the figure. In this way it is possible to obtain a shape suitable for a utilization mode in a meeting room, etc., in which a shorter side of the rectangle is facing the screen side. - 41. The
lamp 10 in the present embodiment is a metal halide lamp as indicated e.g. in FIG. 3. The functions of the illumination optics including the lamp are as described previously and explanation thereof is omitted here. - 42. A transmission type liquid crystal panel of p-SiTFT e.g. of class, where the diagonal of the image screen is 1 inch long, is used for the liquid
crystal display elements 3 in the present embodiment in order to realize the down-sizing of the whole device. For the liquid crystal display elements, e.g. 3R, there are disposed the incident side polarizer 20R, which is a polarizer transmitting linearly polarized light, and the exit side polarizer 21R, which is a polarizer transmitting linearly polarized light having a polarization plane, rotated by 90° with respect to theincident side polarizer 20R. Image information is displayed by controlling the transmitted amount of incident light while combining the function of rotating the polarization plane by the electro-optical effect of liquid crystal in the liquidcrystal display elements 3R with the function of selecting a polarization component of the incident side polarizer 20R and the exit side polarizer 21R serving as polarizers. It can be said that this is identical for B and R. - 43.19 in FIG. 7 represents a case for the
illumination optics 2. In case where any satisfactory image quality performance such as brightness, etc. as a display device can be obtained no more because of an expired life time of the lamp, the lamp can be exchanged by exchanging thecase 19 whole. A concrete example of display means having such a construction will be explained, referring to FIG. 8. - 44.FIG. 8 is a cross-sectional view showing the construction of a concrete example of display means applied to the projection type liquid crystal display device according to the present invention.
- 45. The example indicated in FIG. 8 is so constructed that the
elliptic mirror 5 and thespherical mirror 6 are arranged, through a holdingreflective mirror plate 36. In this way theelliptic mirror 5 and thespherical mirror 6 can be located precisely. Particularly, in case where small size liquid crystal display elements are used, and further in case where the light utilization efficiency is high, since positional precision for theelliptic mirror 5 and thespherical mirror 6, etc. is severe, it is efficient to arrange them through a member. Further the example indicated in FIG. 8 is so constructed that the holdingplate 36 is put betweenother members - 46. In the construction according to the present invention it is useful for increasing in brightness uniformity over the whole screen, light utilization efficiency, etc. to have either one or a plurality of the
elliptic mirror 5, thespherical mirror 6, thefirst lens array 22, thesecond lens array 23, thecondenser lens 7 and the field lens 8 have a shape varied at the peripheral portion with respect to the portion near the optical axis. For example, in case where the central portion near the optical axis of thecondenser lens 7 has a not spherical shape close to a plane, as indicated in FIG. 9, the ratio of the brightness at the peripheral portion to the brightness at the central portion can be increased further, which improves brightness uniformity over the whole screen. - 47. As described above, according to the present invention, it is possible to increase utilization efficiency of the light emitted by the light source and thus to realize a bright projection type liquid crystal display device having a small size and a good image quality performance.
Claims (8)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/727,541 US6351295B2 (en) | 1996-06-04 | 2000-12-04 | Projection type liquid crystal display device |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8141621A JPH09325313A (en) | 1996-06-04 | 1996-06-04 | Projection liquid crystal display device |
JP8-141621 | 1996-06-04 | ||
US08/865,085 US6307601B1 (en) | 1996-06-04 | 1997-05-29 | Projection type liquid crystal display device |
US09/727,541 US6351295B2 (en) | 1996-06-04 | 2000-12-04 | Projection type liquid crystal display device |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/865,085 Continuation US6307601B1 (en) | 1996-06-04 | 1997-05-29 | Projection type liquid crystal display device |
Publications (2)
Publication Number | Publication Date |
---|---|
US20010000056A1 true US20010000056A1 (en) | 2001-03-22 |
US6351295B2 US6351295B2 (en) | 2002-02-26 |
Family
ID=15296308
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/865,085 Expired - Lifetime US6307601B1 (en) | 1996-06-04 | 1997-05-29 | Projection type liquid crystal display device |
US09/727,541 Expired - Fee Related US6351295B2 (en) | 1996-06-04 | 2000-12-04 | Projection type liquid crystal display device |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/865,085 Expired - Lifetime US6307601B1 (en) | 1996-06-04 | 1997-05-29 | Projection type liquid crystal display device |
Country Status (7)
Country | Link |
---|---|
US (2) | US6307601B1 (en) |
EP (1) | EP0812115B1 (en) |
JP (1) | JPH09325313A (en) |
KR (1) | KR100266423B1 (en) |
CN (1) | CN1085006C (en) |
DE (1) | DE69724698T2 (en) |
TW (1) | TW382875B (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1400259B1 (en) * | 2002-09-20 | 2005-07-20 | Angel Medical Systems, Inc | System for the detection of cardiac events |
US20090128481A1 (en) * | 2007-11-19 | 2009-05-21 | Texas Instruments Incorporated | Integrated system with computing and imaging capabilites |
Families Citing this family (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6186629B1 (en) * | 1997-12-22 | 2001-02-13 | Sony Corporation | Optical device and display apparatus |
FR2773223B1 (en) * | 1997-12-29 | 2001-12-07 | Thomson Multimedia Sa | IMAGE PROJECTION OR VIEWING SYSTEM |
GB2340619A (en) * | 1998-08-11 | 2000-02-23 | Sharp Kk | Liquid crystal projector with non-uniform lenslet arrays |
JP2000206613A (en) * | 1999-01-11 | 2000-07-28 | Sony Corp | Projection type display device |
JP4521896B2 (en) * | 1999-06-08 | 2010-08-11 | キヤノン株式会社 | Illumination apparatus, projection exposure apparatus, and device manufacturing method |
US6527393B1 (en) * | 1999-07-28 | 2003-03-04 | Seiko Epson Corporation | Illumination optical system and projector using same |
TW522434B (en) * | 2000-06-16 | 2003-03-01 | Matsushita Electric Ind Co Ltd | Lamp unit and image projection apparatus |
KR100381265B1 (en) * | 2000-12-23 | 2003-05-01 | 엘지전자 주식회사 | Illumination System in Liquid Crystal Projector |
KR20080083367A (en) * | 2001-04-25 | 2008-09-17 | 웨이비엔, 인코포레이티드 | Light recovery for projection displays |
US6836576B2 (en) | 2002-02-08 | 2004-12-28 | Wavien, Inc. | Polarization recovery system using light pipes |
US6877882B1 (en) | 2003-03-12 | 2005-04-12 | Delta Electronics, Inc. | Illumination system for a projection system |
JP4972883B2 (en) * | 2005-06-17 | 2012-07-11 | 株式会社日立製作所 | Optical unit and projection-type image display device |
US7621646B2 (en) * | 2006-07-05 | 2009-11-24 | Hewlett-Packard Development Company | Curved band-pass filter |
JP4961193B2 (en) * | 2006-11-13 | 2012-06-27 | 株式会社日立製作所 | Projection type display device and multi-screen display device using the same |
CN102736386B (en) * | 2012-05-21 | 2014-08-13 | 巴可伟视(北京)电子有限公司 | Light source system used for digital projector |
US9646131B2 (en) | 2014-06-27 | 2017-05-09 | Oracle International Corporation | Intelligent image processing for enterprise applications |
US11215916B2 (en) * | 2020-05-28 | 2022-01-04 | DigiEngin Inc. | Compact size multi-channel light engine projection apparatus |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL8901077A (en) | 1989-04-28 | 1990-11-16 | Koninkl Philips Electronics Nv | OPTICAL EXPOSURE SYSTEM AND PROJECTION DEVICE EQUIPPED WITH SUCH A SYSTEM. |
JP2674913B2 (en) | 1991-11-18 | 1997-11-12 | 松下電器産業株式会社 | Lighting equipment |
JP2643713B2 (en) * | 1992-03-13 | 1997-08-20 | 株式会社日立製作所 | LCD projection display |
JPH05268556A (en) | 1992-03-17 | 1993-10-15 | Fujitsu General Ltd | Light source device for projection |
JP2973750B2 (en) * | 1992-03-31 | 1999-11-08 | 松下電器産業株式会社 | Illumination optical device and projection display device using the same |
US5689315A (en) * | 1992-07-15 | 1997-11-18 | Matsushita Electric Industrial Co., Ltd. | Light valve apparatus which is employed in a projection display system and in a view-finder system |
US5541746A (en) * | 1992-08-19 | 1996-07-30 | Sanyo Electric Co., Ltd. | Light source device for use in liquid crystal projectors |
JP3207022B2 (en) * | 1992-11-24 | 2001-09-10 | 株式会社日立製作所 | Light source, illumination device, and liquid crystal projection display device for projection display device |
US5626416A (en) * | 1994-11-29 | 1997-05-06 | Romano; Richard J. | Lamp module apparatus |
JP3976812B2 (en) | 1995-03-09 | 2007-09-19 | セイコーエプソン株式会社 | Polarized illumination device and projection display device |
US5662401A (en) | 1995-12-13 | 1997-09-02 | Philips Electronics North America Corporation | Integrating lens array and image forming method for improved optical efficiency |
-
1996
- 1996-06-04 JP JP8141621A patent/JPH09325313A/en active Pending
-
1997
- 1997-05-26 TW TW086107101A patent/TW382875B/en not_active IP Right Cessation
- 1997-05-29 US US08/865,085 patent/US6307601B1/en not_active Expired - Lifetime
- 1997-06-03 DE DE69724698T patent/DE69724698T2/en not_active Expired - Lifetime
- 1997-06-03 KR KR1019970022893A patent/KR100266423B1/en not_active IP Right Cessation
- 1997-06-03 EP EP97108913A patent/EP0812115B1/en not_active Expired - Lifetime
- 1997-06-04 CN CN97113662A patent/CN1085006C/en not_active Expired - Fee Related
-
2000
- 2000-12-04 US US09/727,541 patent/US6351295B2/en not_active Expired - Fee Related
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1400259B1 (en) * | 2002-09-20 | 2005-07-20 | Angel Medical Systems, Inc | System for the detection of cardiac events |
US20090128481A1 (en) * | 2007-11-19 | 2009-05-21 | Texas Instruments Incorporated | Integrated system with computing and imaging capabilites |
US8674933B2 (en) * | 2007-11-19 | 2014-03-18 | Texas Instruments Incorporated | Integrated system with computing and imaging capabilities |
Also Published As
Publication number | Publication date |
---|---|
DE69724698T2 (en) | 2004-07-08 |
EP0812115A2 (en) | 1997-12-10 |
DE69724698D1 (en) | 2003-10-16 |
CN1085006C (en) | 2002-05-15 |
US6307601B1 (en) | 2001-10-23 |
KR100266423B1 (en) | 2000-09-15 |
US6351295B2 (en) | 2002-02-26 |
JPH09325313A (en) | 1997-12-16 |
CN1178432A (en) | 1998-04-08 |
TW382875B (en) | 2000-02-21 |
EP0812115B1 (en) | 2003-09-10 |
KR980003683A (en) | 1998-03-30 |
EP0812115A3 (en) | 1998-08-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6062695A (en) | Projection type liquid crystal display device | |
US6351295B2 (en) | Projection type liquid crystal display device | |
JP2831510B2 (en) | Liquid crystal display element and liquid crystal display device using the same | |
US7327520B2 (en) | Optical unit and image display apparatus | |
JP2927679B2 (en) | Liquid crystal display | |
US5617152A (en) | Projector system for video and computer generated information | |
JPH08129155A (en) | Projection type picture display device | |
JPH05323268A (en) | Lighting optical device and liquid crystal display device using the same | |
JP2978202B2 (en) | Projection display device | |
JP2823722B2 (en) | Polarization combining element and liquid crystal display device using the same | |
JP2000098490A (en) | Display device | |
JP3157599B2 (en) | Display device | |
JPS6337316A (en) | Projection type color display device | |
JPH08201759A (en) | Projection type liquid crystal display device | |
JPH1138529A (en) | Projection type display device | |
JP2000098235A (en) | Display device and its optical device, light source unit | |
JPH08334726A (en) | Projection device | |
JP2002189248A (en) | Illuminator and projection type liquid crystal display device | |
JPH04127136A (en) | Light transmission tube provided with many minute opening and projection type display device using same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
CC | Certificate of correction | ||
FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
FPAY | Fee payment |
Year of fee payment: 8 |
|
FEPP | Fee payment procedure |
Free format text: PAYER NUMBER DE-ASSIGNED (ORIGINAL EVENT CODE: RMPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
AS | Assignment |
Owner name: HITACHI CONSUMER ELECTRONICS CO., LTD., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HITACHI, LTD.;REEL/FRAME:030802/0610 Effective date: 20130607 |
|
REMI | Maintenance fee reminder mailed | ||
LAPS | Lapse for failure to pay maintenance fees | ||
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20140226 |