JPH08152632A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: To enhance the utilizing efficiency of the white light of a light source by spectrally diffracting the white light, condensing the light beams of respective color components and making them incident on the picture elements of a liquid crystal display panel corresponding to three primary colors by using a hologram and irradiating a black matrix with the light beams of the other components. CONSTITUTION: As for the respective color light beams spectrally diffracted and made incident on by the hologram 12 arranged on the light incident side of the liquid crystal display panel, the light beam of prescribed wavelength among the separated color light beams of the specified wavelength is respectively made incident on the picture elements 15-17 corresponding to three primary colors. By the hologram 12 constituted so that the light beams of the other wavelength are made incident other than the picture elements, the light beams 19r, 19g and 19b of the respective color components are condensed and made incident on the respective picture elements 15-17 by spectrally diffracted the white color 11 emitted from a light source. Besides, the black matrix 18 is irradiated with the light beams of the other components.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device such as a liquid crystal projector using a hologram.

[0002]

2. Description of the Related Art Light from one light source is converted into an R (red) component,
It is decomposed into three lights of G (green) component and B (blue) component, made incident on the corresponding three liquid crystal display panels, and decomposed into three colors of R, G, B on each liquid crystal display panel for display. There is a three-plate type liquid crystal projector in which a color image such as a television image thus generated is combined by reflection and transmission and enlarged and projected on a screen by one projection lens. There is also a single-plate type liquid crystal projector using one liquid crystal display panel with a color filter.

In a conventional liquid crystal projector using a color filter, white light as a light source is incident from behind a liquid crystal display panel with a color filter and projected on a screen. In particular, the light incident on the color filter is evenly incident on the openings of the respective color cells and the black matrix.

[0004]

As described above, in the liquid crystal projector using the conventional color filter, as described above, the white light is only incident from the rear of the liquid crystal display panel with the color filter. Since the area occupied by the black matrix other than the R, G, and B color cells is large, the light hitting the black matrix is wasted.
Therefore, there is a problem that the utilization efficiency of the white light of the light source in the liquid crystal projector is reduced.

An object of the present invention is to disperse white light in a liquid crystal display device such as a liquid crystal projector by using a hologram for each color cell of R, G, B such as a color filter or a liquid crystal display panel. Then, the light of each color component is collected and made incident, and the light of the other components is applied to the black matrix,
The purpose is to significantly improve the utilization efficiency of white light from the light source.

Another object of the present invention is to provide all the light diffracted and condensed by using holograms for the color filter cells R, G and B in the liquid crystal display device such as the liquid crystal projector as described above. By making the light incident, the utilization efficiency of the white light of the light source is significantly improved.

[0007]

In order to solve the above-mentioned problems, the invention according to claim 1 arranges periodically the light source means for emitting white light and the pixels corresponding to the three primary colors, and the above-mentioned source of the light source from behind. In a liquid crystal display device provided with a liquid crystal display panel that emits white light to perform color display, the white light of the light source is separated into specific wavelength colors and is incident on pixels corresponding to the three primary colors of the liquid crystal display panel. A hologram is provided on the light-incident side of the liquid crystal display panel, and the hologram is made such that light of a predetermined wavelength among the separated specific wavelength colors is made incident on each of the pixels corresponding to the three primary colors. It is characterized in that the light of the wavelength is arranged to be incident on the liquid crystal display panel other than the pixels.

The invention according to claim 2 is based on claim 1.
The invention described above is characterized in that the light having the other wavelength is made incident on the black matrix portion of the liquid crystal display panel.

The invention according to claim 3 is characterized in that, in the invention according to claim 1, a plurality of cells of the hologram are provided corresponding to one pixel.

Further, according to the invention of claim 4, light source means for emitting white light and color filter cells corresponding to pixels corresponding to the three primary colors are periodically arranged, and the white light of the light source is emitted from behind. In a liquid crystal display device including a liquid crystal display panel that performs color display by entering, a hologram that separates the white light of the light source into a specific wavelength color and enters a pixel corresponding to the three primary colors of the liquid crystal display panel is described above. One cell of the hologram is provided on the light incident side of the liquid crystal display panel, and one cell of the hologram is made to correspond to the color filter cell, and all of the color lights diffracted and condensed by the hologram are made to correspond to the color filter cell. The configuration is characterized in that the hologram is arranged so as to be incident.

[0011]

According to the invention described in claim 1, with respect to each color light which is spectrally incident by the hologram arranged on the light incident side of the liquid crystal display panel, the pixel corresponding to the three primary colors is
Since the liquid crystal display device is provided with a hologram configured to enter light of a predetermined wavelength in the separated specific wavelength colors and to enter light of other wavelengths in addition to the pixel, the pixel R, For G and B, the white light emitted from the light source can be dispersed by the hologram to collect and enter the light of each color component, and the light of other wavelengths can be applied to other than the pixel. The use efficiency of white light of the light source can be significantly improved.

According to the second aspect of the invention, since the liquid crystal display device in which the light of the other wavelengths of the first aspect is incident on the black matrix portion, the light of the other wavelengths is incident on the pixels. Can be applied to the black matrix, and thus the utilization efficiency of the white light of the light source can be greatly improved.

According to the invention described in claim 3, since the liquid crystal display device is provided with a plurality of cells of the hologram according to claim 1 corresponding to one pixel, a plurality of cells are provided for one pixel. With the hologram cell, it is possible to diffract and collect light of a predetermined wavelength, and thus it is possible to greatly improve the utilization efficiency of white light from the light source.

Further, according to the invention described in claim 4, for each color light which is spectrally incident by the hologram arranged on the light incident side of the liquid crystal display panel, one cell of the hologram is provided for each color filter cell. Since the liquid crystal display device is provided with the hologram configured to make all of the color lights diffracted and collected be incident on the corresponding color filter cells, the light sources for the color filter cells R, G, and B are provided. A liquid crystal display device using a color filter can be used because all of the color lights diffracted and collected by dispersing the emitted white light by a hologram can be made incident on the corresponding color filter cell and the black matrix is not exposed to the light. The utilization efficiency of white light of the light source can be significantly improved.

[0015]

Embodiments of the liquid crystal display device according to the present invention will be described below with reference to FIGS. First, FIG. 1 shows a configuration of a liquid crystal projector as an example of a liquid crystal display device to which the present invention is applied. Light source means 1 is composed of a metal halide lamp 2 and a reflector 3 which are light sources, and is emitted by the metal halide lamp 2. The white light (including the light reflected by the reflector 3) 11 is
The light is transmitted through the incident side polarization plate 4 and is incident on the hologram and color filter section 10 as oblique parallel light, and is incident on the liquid crystal display panel 5 through the hologram and color filter section 10. Incidentally, 6 is a liquid crystal surface of the liquid crystal display panel 5. Then, the image light transmitted through the liquid crystal display panel 5 is transmitted through the emission side polarization plate 7 and enlarged and projected on a screen (not shown) by the projection lens 8. A cooling fan 9 forcibly cools the inside of the liquid crystal projector.

Hologram and color filter section 10
The glass substrate 1 is provided between the transmission hologram 12 and the color filter 13 as shown in FIG.
4 is interposed and integrated. The color filter 13 periodically arranges R pixels 15, G pixels 16, and B pixels 17 of three colors, which form one pixel of the liquid crystal display panel 5, and has a black matrix 18 that partitions each pixel from each other. are doing. Here, in the illustrated example, the white light 11 is incident on the hologram 12 at an incident angle of 20 ° with respect to the vertical direction. In addition, the distance between the hologram 12 and the color filter 13 is 1100μ.
m (1.1 mm), and a transparent glass substrate 14 having a thickness corresponding to this is interposed between the two. And
The R pixel 15, the G pixel 16, and the B pixel 17 have a 1-dot 175 μm pitch. The pitch of the openings of the R, G, and B pixels is 54 μm.

By the way, the transmission type hologram 12 arranged on the light incident side of the color filter 13 has three color filter cells R, G and B (pixels 15, 16 and 15) constituting one pixel of the liquid crystal display panel 5. Each of the groups 17) is arranged in an array at the same pitch as the pixel pitch of the color filter 13. Each unit hologram is obliquely incident on the hologram 12 (in the example shown in the figure, 20 degrees relative to the normal line).
It is formed in a Fresnel zone plate shape so as to diffract the white light 11 having an incident angle of (°) and focus it on each pixel 15, 16, 17 of the color filter 13 at a position offset from the corresponding unit hologram. . As the hologram 12, a relief type, a phase type, an amplitude type or the like, which has little or no wavelength dependency of diffraction efficiency, is used. Diffraction efficiency does not depend on the wavelength or is small, as in the Lippmann hologram, it is not a type that diffracts only a specific wavelength and does not diffract other wavelengths, and one wavelength is diffracted by one diffraction grating. Means what to do. This diffraction grating having little wavelength dependence generally diffracts at different diffraction angles depending on the wavelength.

Therefore, the diffraction angles of the unit holograms differ depending on the wavelength of the incident white light 11, and the focusing positions for each wavelength are dispersed in the direction parallel to the hologram 12 surface. Therefore, the R wavelength component of the white light 11 is in the R pixel 15 of the color filter 13, the G wavelength component is in the G pixel 16 of the color filter 13, and the B wavelength component is in the B pixel 17 of the color filter 13. Each is diffracted and collected. Then, the respective color components diffracted and collected in this way are respectively supplied to the respective color filter cells R, G, B (pixel 1
5, 16 and 17) pass through with almost no attenuation, and color display is performed according to the state of the pixel at the corresponding position (the liquid crystal surface 6 of the liquid crystal display panel 5).

As described above, in the liquid crystal projector to which the present invention is applied, by utilizing the difference in the diffraction angle depending on each wavelength of the hologram 12, each color filter cell R,
Corresponding wavelength components are diffracted and incident on G and B (pixels 15, 16 and 17) (main rays 19r and 19g shown in FIG. 2,
19b) so that each wavelength component of the white light 11 from the metal halide lamp 2 can be made incident on each color cell without waste, so that the utilization efficiency thereof can be greatly improved.

Particularly, in the first embodiment of the present invention, in the hologram 12 described above, each color component is the same for each color light R, G, B which is spectrally incident on the one pixel of the liquid crystal by the hologram 12. The hologram cells 21, 22, and 23 are provided so that the color components correspond to each other. Then, for each of the color lights R, G, and B which are spectrally incident by the hologram cell 21 corresponding to the color filter cell R (pixel 15), the R component light (light having a wavelength of 0.64 μm) is converted into the color filter cell R ( The light is incident on the center of the pixel 15) substantially perpendicularly (at an incident angle of 1 ° with respect to the normal line in the illustrated example) (see the chief ray 19r in FIG. 2), and the other G component light and B
The component light strikes the black matrix 18 between the color filter cell G (pixel 16).

The color filter cell G (pixel 1
6), of the respective color lights R, G, and B that are spectrally incident by the hologram cell 22 and are incident on the color filter cell G (pixel 1).
6) is incident substantially perpendicular to the center of the center (incident angle of 1 ° with respect to the normal in the illustrated example) (see the chief ray 19g in FIG. 2), and the other R component light is emitted from the color filter cell R (pixel 15). The light of the B component is made to hit the black matrix 18 between the color filter cell B (pixel 17). Further, each color light R, G, which is spectrally incident by the hologram cell 23 corresponding to the color filter cell B (pixel 17), is input.
Regarding B, the B component light (light having a wavelength of 0.46 μm) is incident substantially perpendicularly to the center of the color filter cell B (pixel 17) (incident angle of 1 ° with respect to the normal in the illustrated example) (FIG. 2). (See the principal ray 19b of FIG. 2), the other R component light and the G component light impinge on the black matrix 18 between the color filter cell G (pixel 16). The length of one of the hologram cells 21, 22, 23 as described above in the long side direction is the same as the color filter cells R, G, B.
Corresponding to the pitch of 175 μm.

Here, for the points A, B, and C at which the white light 11 of the illustrated example enters the hologram 12, the pitches d _A , d _B , and d _C of the hologram 12 are d _A = 1.417 d. _B = 1.694 d _C = 1.971. The setting of the light incident on each color cell and the black matrix by diffracting and condensing the hologram 12 as described above is performed by appropriately designing the hologram 12, setting the distance between the hologram 12 and the color filter 13, and setting the white light 1.
This is configured by appropriately setting the incident angle of the first hologram 12 on the hologram 12.

According to the liquid crystal projector of the first embodiment described above, the white light 11 emitted from the metal halide lamp 2 is separated by the hologram 12 and diffracted and condensed, and in particular, the chief rays 19r, 19g and 19b are shown in FIG. As shown in FIG. 3, the hologram cell 21 allows the R component light to enter the color filter cell R, the hologram cell 22 allows the G component light to enter the color filter cell G, and the hologram cell 23 allows the B component light to enter the color filter cell B. Since the light is transmitted almost vertically, it is possible to effectively use the light that has hitherto been wasted by hitting the black matrix.

By the way, in the first embodiment described above, the color filter 13 is attached to the liquid crystal display device, but since each color light can be produced also by the hologram 12 (each hologram cell 21, 22, 23), the color filter 13 The filter 13 may be omitted. Further, in the first embodiment, the hologram 12 has no or little wavelength dependency of diffraction efficiency, but a hologram having wavelength dependency of diffraction efficiency may be used. In that case, color filter 13
The R pixel 15 corresponds to a cell that diffracts and collects the R component light, the G pixel 16 corresponds to a cell that diffracts and collects the G component light, and the B pixel 17 corresponds to the B pixel 17. The holograms are arranged so that the cells that diffract and collect the component light correspond.

Next, FIG. 3 shows a modified example of the structure of the hologram 12. In this modified example, the diffractive and condensing action, which was performed by one cell of the hologram 12 in the first embodiment, is performed by two cells. In the figure,
The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. That is, in this modification, the hologram cells 21, 22 and 23 respectively corresponding to the color filter cells R, G and B are replaced by two hologram cells 21a and 21b and a hologram cell 22 as shown in the figure.
a, 22b and hologram cells 23a, 23b, respectively. Then, the two hologram cells 21a,
21b, each of the color lights R, which are split and incident by
For G and B, the light of the R component is the color filter cell R
(See principal ray 19r), and the other G component light and B component light respectively strike the black matrix 18 between the color filter cells G.

Further, the two hologram cells 22a, 22
b, the respective colored lights R, G,
Regarding B, the G component light is incident on the center of the color filter cell G (see the chief ray 19g), and the other R component light strikes the black matrix 18 between the color filter cell R and the B component, respectively. The light of (6) is made to strike the black matrix 18 between the color filter cells B, respectively. Furthermore, for each of the color lights R, G, and B that are spectrally incident by the two hologram cells 23a and 23b, the B component light is incident on the center of the color filter cell B (the chief ray 19).
b)), and the other R component light and the G component light respectively strike the black matrix 18 between the color filter cells G.

Next, a second embodiment of the present invention will be described. FIG. 4 shows a second embodiment of the main configuration of the present invention. As in the first embodiment, 11 is white light, 12 is a hologram, 13 is a color filter, 14 is a glass substrate, 31 Is an opening of each of the R, G, and B cells of the color filter 13, 32 is a black matrix, 2
Reference numeral 4 is a hologram cell corresponding to the opening 31 of the color filter 13. Here, in the illustrated example, white light 1
1 enters the hologram 12 at an incident angle of 5 ° with respect to the vertical direction. The distance between the hologram 12 and the color filter 13 is 400 μm, and R, G, B
The pixels have a pitch of 88 μm per dot, and the pitch of the openings 31 is 54 μm. The length of one side of the hologram cell 24 in the long side direction is 88 μm corresponding to the pitch of the R, G, and B pixels.

The opening 3 of the color filter 13
All of the respective color lights R, G, and B which are split and made incident by the hologram cell 24 corresponding to 1 are diffracted and condensed and made to enter the opening 31. Here, for the points I and II where the white light 11 in the illustrated example is incident on the hologram 12, the pitches d _I and d _II of the hologram 12 are d _I = 3.55 d _II = 14.3.

According to the liquid crystal projector of the second embodiment described above, the white light 11 emitted from the metal halide lamp 2 is dispersed by the hologram 12 and is diffracted and condensed, in particular, by the hologram cell 24 and diffracted and condensed. Since all of the respective colored lights R, G, and B to be transmitted are transmitted to the opening portion 31, the black matrix 32 is prevented from being hit by the light and wasted, and therefore, the light utilization efficiency can be significantly improved. .

In the above embodiment, the liquid crystal projector has the arrangement of the main parts shown in FIG. 1, but the present invention is not limited to this. It may be.
In addition, although the liquid crystal display panel with the color filter is used in the embodiments, the liquid crystal projector using the hologram does not necessarily need the color filter because each color light can be produced also by the hologram. However, there is an advantage that the color purity can be corrected by using the color filter together. Further, the incident angle of light with respect to the hologram, the distance between the color filter and the hologram, and the like are arbitrary, and it is needless to say that the specific detailed structure and the like can be appropriately changed.

[0031]

As described above, according to the liquid crystal display device of the first aspect of the present invention, the respective color lights that are spectrally incident by the hologram arranged on the light incident side of the liquid crystal display panel are compatible with the three primary colors. Each pixel R, G has a hologram that allows light of a predetermined wavelength in the separated specific wavelength color to enter the selected pixel and also allows light of another wavelength to enter in addition to the pixel. , B, the white light emitted from the light source is dispersed by the hologram, and the light of each color component can be condensed and made incident, and the light of other wavelengths can be applied to other than the pixel. Therefore, the utilization efficiency of the white light of the light source can be significantly improved.

According to the liquid crystal display device of the second aspect of the invention, since the light of the other wavelength of the first aspect is incident on the black matrix portion, the wavelength other than the wavelength of incident on the pixel is changed. Light can be applied to the black matrix. Therefore, the utilization efficiency of the white light of the light source can be significantly improved.

According to the liquid crystal display device of the third aspect of the present invention, since the plurality of cells of the hologram of the first aspect are provided corresponding to one pixel, one pixel is provided. In addition, a plurality of hologram cells can diffract and collect light of a predetermined wavelength. Therefore, the utilization efficiency of the white light of the light source can be significantly improved.

Further, according to the liquid crystal display device of the fourth aspect of the present invention, for each color light that is spectrally incident by the hologram arranged on the light incident side of the liquid crystal display panel, one color filter cell is provided. Since the cells are made to correspond to each other, and all the color lights diffracted and collected are made incident on the corresponding color filter cells,
For the color filter cells R, G, B, the white light emitted from the light source is dispersed by the hologram, and all the respective color lights diffracted and condensed can be made incident on the corresponding color filter cell, and the black matrix is not illuminated. You can prevent it from hitting. Therefore, in a liquid crystal display device using a color filter, it is possible to significantly improve the utilization efficiency of white light from a light source.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a liquid crystal projector as an example of a liquid crystal display device to which the present invention is applied.

FIG. 2 is a diagram showing a first embodiment of the configuration of a hologram and a color filter portion, which are essential parts of the present invention.

FIG. 3 is a diagram showing a modified example of the configuration of the hologram in FIG.

FIG. 4 is a diagram showing a second embodiment of the main configuration of the present invention, similar to FIG.

[Explanation of symbols]

 1 light source means 2 light source 3 reflector 4 incident side polarization plate 5 liquid crystal display panel 6 liquid crystal surface 7 emission side polarization plate 8 projection lens 9 cooling fan 10 hologram and color filter section 11 white light 12 hologram 13 color filter 14 glass substrate 15, 16 , 17 pixels 18 black matrix 19 chief rays 21, 22, 23, 24 hologram cell 31 color filter aperture 32 black matrix

Claims (4)

[Claims] 1. A liquid crystal display comprising: a light source means for emitting white light; and a liquid crystal display panel for periodically displaying pixels corresponding to the three primary colors and for displaying the white light from the light source from behind to perform color display. In the device, a hologram that separates the white light of the light source into a specific wavelength color and is incident on a pixel corresponding to the three primary colors of the liquid crystal display panel is provided on the light incident side of the liquid crystal display panel, and the hologram is Arranged so that light of a predetermined wavelength in the separated specific wavelength colors is made incident on pixels corresponding to the three primary colors, respectively, and light of other wavelengths is made incident on other than the pixels of the liquid crystal display panel. A liquid crystal display device characterized by the above. 2. The liquid crystal display device according to claim 1, wherein the light of the other wavelength is incident on the black matrix portion of the liquid crystal display panel. 3. The liquid crystal display device according to claim 1, wherein a plurality of cells of the hologram are provided corresponding to one of the pixels. 4. A liquid crystal which emits white light and a color filter cell corresponding to pixels corresponding to the three primary colors is periodically arranged, and the white light of the light source is incident from behind to perform color display. In a liquid crystal display device including a display panel, a hologram that separates the white light of the light source into a specific wavelength color and enters a pixel corresponding to the three primary colors of the liquid crystal display panel is provided on the light incident side of the liquid crystal display panel. One hologram cell is provided for each color filter cell, and the hologram is arranged so that all color lights diffracted and condensed by the hologram are incident on the corresponding color filter cell. A liquid crystal display device characterized by the above.