JPH08152594A - Liquid crystal projector - Google Patents

Abstract

PURPOSE: To suppress the incidence angle of a projection lens to be small, to prevent a decrease in contrast, and to nearly equalize lightness of each wavelength component. CONSTITUTION: The light from a light source is split by holography 13 into wavelength components of red, green, and blue, which are converged and made incident on respective color filters R, G, and B of the color filter 18 of a liquid crystal display element 14 almost at a right angle, and the diffusion of projection light projected from the liquid crystal cell 17 of the liquid crystal display element 14 is corrected to a nearly constant direction by a diffusion correcting element 15 to reduce the divergence of the light made incident on a projection lens and suppress the incidence angle of the projection lens to be small; even if the angles of incidence of the respective wavelength components made incident on the liquid crystal display element 14 have differences, the diffusion is corrected into a nearly constant direction by the diffusion correcting element 15, thereby making small the differences in incidence angle among the wavelength components made incident on the projection lens, preventing the decrease in contrast, and nearly equalizing the lightness of each wavelength component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector for enlarging and projecting a color image.

[0002]

2. Description of the Related Art Conventionally, a liquid crystal projector irradiates a back surface of a liquid crystal display element with light from a light source and magnifies and projects a color image displayed on the liquid crystal display element by a projection lens. In this liquid crystal projector, the liquid crystal display element is composed of a liquid crystal cell and a color filter, a color filter is arranged on the light incident side, and the light from the light source is dispersed into three wavelength components of red, green and blue by the hologram. The light of each wavelength component, which is condensed by each corresponding color filter of the color filter and has passed through each color filter, is incident on each corresponding pixel of the liquid crystal cell. In this case, in order to improve the optical characteristics of the liquid crystal enclosed in the liquid crystal cell and to increase the apparent aperture ratio, it is necessary to allow the light from the light source to enter the color filter as vertically as possible. An example thereof is shown in FIG. In this liquid crystal projector, parallel light from a light source is incident on the hologram 1 at a predetermined incident angle, so that the hologram 1 splits light into wavelength components of three colors of red, green, and blue, and each of the split light components is split. The light of the wavelength component is condensed toward the respective color filters R, G, B of the color filter 2 and is made incident substantially vertically.

[0003]

However, in such a liquid crystal projector, the light of each wavelength component dispersed by the hologram 1 is condensed by the hologram 1 on each color filter R, G, B of the color filter 2. Therefore, when the light passes through the color filter 2 and the liquid crystal cell 3 arranged on the emission side, the transmitted light is emitted in the diffusion direction, which increases the take-in angle of the projection lens and the projection angle accordingly. There is a problem that the lens becomes large, and if there is a large difference in the incident angle between the wavelength components incident on the color filter 2, the contrast is lowered and there is a difference in brightness between the wavelength components. There is also. It is an object of the present invention to suppress the capture angle of the projection lens, prevent the contrast from decreasing, and make the brightness of each wavelength component substantially uniform.

[0004]

According to the first aspect of the present invention,
A liquid crystal projector that irradiates light from a light source on the back surface of a liquid crystal display element and magnifies and projects an image displayed on the liquid crystal display element as a color image with a projection lens. And a hologram that disperses the light into a specific wavelength component and focuses it on the pixels of the corresponding color of the liquid crystal display element to make it enter the incident surface of the liquid crystal display element almost perpendicularly. And a diffusion correction element that corrects the diffusion of the light of each wavelength component condensed by the light source in a substantially constant direction. In this case, as described in claim 4, when the liquid crystal display element is composed of only the liquid crystal cell, it is desirable to dispose the diffusion correction element on the exit side of the liquid crystal cell. As described above, when the liquid crystal display element is composed of the liquid crystal cell and the color filter, it is not always necessary to dispose the diffusion correction element on the exit side of the liquid crystal cell, and the diffusion filter is disposed on the incident side of the liquid crystal cell. A diffusion correction element may be arranged between the liquid crystal cells.

According to a seventh aspect of the present invention, in a liquid crystal projector for irradiating the back surface of a liquid crystal display element with light from a light source, and enlarging and projecting an image displayed on the liquid crystal display element as a color image with a projection lens, the light source and the liquid crystal display. Between the hologram and the liquid crystal display element, a hologram that is arranged between the hologram and the liquid crystal display element, is disposed between the hologram and the liquid crystal display element, and splits the light from the light source into specific wavelength components and condenses the light toward the pixels of each corresponding color of the liquid crystal display element. And a refraction element for refracting the light of each wavelength component dispersed and condensed by the hologram in a substantially constant direction and making the light incident substantially perpendicularly to the incident surface of the liquid crystal display element. It is a thing. In this case, claim 8
As described in 9 and 9, the refraction element corresponds to a unit prism lens corresponding to a unit pixel composed of three color pixels for red, green, and blue of the liquid crystal display element, or each pixel of the liquid crystal display element. It is desirable to have a structure in which a large number of microprism lenses are arranged. Further, as described in claim 10, the incident surface of the microprism lenses is arranged for each pixel of the liquid crystal display element according to each wavelength component dispersed by the hologram. It is desirable that the inclined surfaces are formed at different angles.

[0006]

According to the invention described in claim 1, when the light from the light source is incident on the hologram, the incident light is dispersed into a specific wavelength component by the hologram and is condensed on each pixel of the corresponding color of the liquid crystal display element. When the incident light passes through the pixels of the corresponding color of the liquid crystal display element and is emitted, the emitted light is emitted in the diffusing direction. The diffusion will be corrected. Therefore, the spread of the light incident on the projection lens becomes small, and the acceptance angle of the projection lens can be suppressed to a small value. Therefore, the projection lens can be made small and each wavelength component incident on the liquid crystal display element can be made smaller. Even if there is a difference in the incident angle, the diffusion correction element corrects the diffusion in a substantially constant direction, so the difference in the incident angle between the wavelength components incident on the projection lens becomes small, and this prevents a decrease in contrast. The brightness in each wavelength component can be made substantially uniform. In this case, as described in claims 5 and 6, when the diffusion correction element is arranged between the color filter arranged on the incident side of the liquid crystal cell and the liquid crystal cell, each wavelength transmitted through each color filter of the color filter. Since the diffusion of the component light is corrected in a substantially constant direction by the diffusion correction element, it is possible to reduce the spread of the light incident on the liquid crystal cell, and the light of each wavelength component is almost perpendicular to each pixel of the liquid crystal cell. It is possible to improve the optical characteristics of the liquid crystal and increase the apparent aperture ratio.

According to the invention described in claim 7, when the light from the light source is incident on the hologram, the incident light is dispersed into a specific wavelength component by the hologram and directed to the pixels of the corresponding colors of the liquid crystal display element. The light is condensed, but the light of each wavelength component is refracted in a substantially constant direction by the refraction element arranged between the hologram and the liquid crystal display element, and is incident on the pixel of each corresponding color of the liquid crystal display element substantially vertically. Will be done.
Therefore, the optical characteristics of the liquid crystal are improved, the apparent aperture ratio can be increased, and since the light is emitted almost vertically from the liquid crystal display element, the spread of the light incident on the projection lens can be reduced, The capture angle of the projection lens can be suppressed to a small value, which allows the projection lens to be formed small and the difference in the incident angle between the respective wavelength components incident on the liquid crystal display element to be reduced, thereby lowering the contrast. It is possible to prevent and make the brightness of the wavelength components of each color substantially uniform. In this case, as described in claims 9 and 10, as the refraction element, one in which microprism lenses corresponding to each pixel of the liquid crystal display element are arranged is used, and the incident surface of each microprism lens is dispersed by a hologram. If each pixel of the liquid crystal display element is formed on an inclined surface having a different angle according to each wavelength component, the light of each wavelength component can be made to enter each pixel of the liquid crystal display element in a state of being extremely vertical.

[0008]

【Example】

[First Embodiment] A first embodiment of the liquid crystal projector of the present invention will be described below with reference to FIGS. FIG. 1 is an overall configuration diagram of a liquid crystal projector. In this figure, 10 is a light source, and a reflector 1 having a parabolic surface.
It is arranged at a focal position of 1. The reflector 11 reflects the light generated from the light source 10 as a light beam parallel to the optical axis 12. A hologram 13 is arranged on the reflection side of the reflector 11. On the incident side of the hologram 13, parallel light rays are incident from the light source 10 side at a predetermined incident angle described later. A liquid crystal display element 14 is arranged in parallel on the exit side of the hologram 13 with a predetermined distance. A diffusion correction element 15 for correcting the diffusion of light is arranged on the emission surface of the liquid crystal display element 14. A projection lens 16 for enlarging and projecting the image displayed on the liquid crystal display element 14 is arranged on the exit side of the diffusion correction element 15.

The liquid crystal display element 14 is composed of a liquid crystal cell 17 and a color filter 18, and has a structure in which the color filter 18 is arranged on the incident surface of the liquid crystal cell 17. The liquid crystal cell 17 is one in which liquid crystal is sealed between a pair of transparent electrode substrates with a sealing material, and has a structure in which a large number of pixels are arranged in a dot matrix. A polarizing plate (not shown) is provided on each of the incident side and the emitting side of the liquid crystal cell 17. Color filter 18
Is formed by arranging three color filters R, G, B of three colors of red, green, and blue corresponding to each pixel of the liquid crystal cell 17, and as shown in FIG. It has a structure in which a black matrix BM is provided.

The hologram 13 has no or little wavelength dependence of diffraction efficiency, and one diffraction grating diffracts any wavelength and diffracts at different diffraction angles depending on the wavelength. This hologram 13 is shown in FIG.
As shown in, the incident angle of the incident light is set to a predetermined angle so that the emitted light is incident on the color filter 18 substantially vertically. In addition, the hologram 13 splits light incident at a predetermined incident angle into light of three types of wavelength components of red, green, and blue, and the dispersed light of each wavelength component corresponds to each of the color filters 18. The light is focused on the color filters R, G, B, and as shown in FIG. 3, a large number of unit holograms 13a corresponding to the unit filters including the three color filters R, G, B of the color filter 18 are arranged. The diffraction grating of each unit hologram 13a has a structure formed at a uniform pitch d.

That is, the relationship between the incident angle of the light incident on the hologram 13 and the hologram 7 is that the incident angle with respect to the normal line 19 of the hologram 13 is θ, the outgoing angle from the hologram 13 is ψ, the wavelengths of red, green and blue. Where λ and the pitch of the diffraction grating of the hologram 13 are d, the condition of sin θ + sin ψ = λ / d (1) is satisfied. In the hologram 13, the light incident at the incident angle θ is split into red, green, and blue wavelength components, and the split red wavelength component light is condensed almost vertically on the red filter R of the color filter 18, Light of the green wavelength component is condensed almost vertically on the green filter G, and light of the blue wavelength component is condensed almost vertically on the blue filter B. In this embodiment, each unit hologram 13a of the hologram 13 is formed so that the light of the green wavelength component is used as the reference light and a part of the light of the green wavelength component is vertically incident on the green filter G. .

In the diffusion correction element 15 arranged on the exit surface of the liquid crystal cell 17, a large number of unit lenses 15a corresponding to the unit filters composed of the three color filters R, G and B of the color filter 18 are arranged in a dot matrix. It is a lens array. Each unit lens 15a has a structure in which the diffusion of light of each wavelength component transmitted through the liquid crystal cell 17 is corrected in a substantially constant direction and is incident on the projection lens 16.

In such a liquid crystal projector, as shown in FIG. 1, when the light from the light source 10 is incident on the hologram 13 as a light beam parallel to the optical axis 12 at a predetermined incident angle by the reflector 11, the hologram 13 produces red light. ,
Color filter 1 is split into light of each wavelength component of green and blue.
The light is focused on the corresponding color filters R, G, B of 8 and is incident almost vertically. That is, of the split light, the light of the red wavelength component is focused on the red filter R of the color filter 18, the light of the green wavelength component is focused on the green filter G, and the light of the blue wavelength component is focused on the blue filter B. Collected. And
The light of each wavelength component transmitted through each color filter R, G, B is incident on each pixel of the liquid crystal cell 17, and the light transmitted through each pixel is incident on the diffusion correction element 15. The light incident on the diffusion correction element 15 is emitted in a substantially constant direction with its diffusion direction suppressed by each unit lens 15a of the diffusion correction element 15. The emitted light is enlarged and irradiated onto a screen (not shown) by the projection lens 16. As a result, the image displayed on the liquid crystal cell 17 is enlarged and projected as a color image on the screen.

Thus, in this liquid crystal projector,
The light of each wavelength component that has passed through the color filter 18 and the liquid crystal cell 17 is emitted in a substantially constant direction with its diffusion direction suppressed by each unit lens 15a of the diffusion correction element 15, so that the light incident on the projection lens 16 is spread. Is small, the acceptance angle of the projection lens 16 can be suppressed to be small, the projection lens 16 can be formed small, and the difference in the incident angle of light between the wavelength components incident on the projection lens 16 becomes small. In addition, it is possible to prevent a decrease in contrast and to make the brightness of each wavelength component substantially uniform.

Further, in this liquid crystal projector, the hologram 13 disperses the light of the respective wavelength components of red, green and blue into the corresponding color filters R of the color filter 18.
Since the light is condensed on G and B, the light of the complementary color component does not enter the respective color filters R, G, B of the color filter 18, and therefore the loss of light by the respective color filters R, G, B is prevented. In addition, the color purity can be improved, and since the black matrix BM of the color filter 18 is not irradiated with light, loss of light in the black matrix BM can be prevented and the light source 1
The utilization efficiency of light from 0 can be improved.

In the first embodiment, the liquid crystal cell 17
Although the case where the liquid crystal display element 14 is configured by the color filter 18 and the color filter 18 has been described, the present invention is not limited to this, and the liquid crystal display element may be configured only by the liquid crystal cell 17. In this case, the hologram 13 disperses the light from the light source 10 into light of each wavelength component of red, green, and blue, and the separated light of each wavelength component is used for red, green, and blue of the liquid crystal cell 17. By condensing the light on each pixel, a color image can be obtained without the color filter 18.

[Second Embodiment] Next, a second embodiment of the liquid crystal projector of the present invention will be described with reference to FIG. The same parts as those in the first embodiment shown in FIGS. 1 to 3 are designated by the same reference numerals, and the description thereof will be omitted as appropriate. This liquid crystal projector has a structure in which a diffusion correction element 20 is arranged between the liquid crystal cell 17 and the color filter 18 that form the liquid crystal display element 14, that is, on the emission surface of the color filter 18. The diffusion correction element 20 is a lens array in which microlenses 20a corresponding to the red, green, and blue color filters R, G, B of the color filter 18 are arranged in a dot matrix. Similar to the function of the unit lens 15a of the first embodiment, each microlens 20a corrects the diffusion of light for each wavelength component transmitted through each color filter R, G, B of the color filter 18 in a fixed direction. ,
The projection lens 16 has a structure in which the light enters the projection lens 16 almost uniformly.

In such a liquid crystal projector, since each microlens 20a of the diffusion correction element 20 corresponds to each color filter R, G, B, each color filter R, G,
It is possible to correct the diffusion of the light for each wavelength component that has passed through B in a fixed direction, and therefore, as compared with the first embodiment,
The spread of the light incident on the projection lens 16 can be reduced, the acceptance angle of the projection lens 16 can be further reduced, and each wavelength component incident on the projection lens 16 can be smaller than that of the first embodiment. Since the difference in the incident angle of the light becomes smaller, it is possible to further prevent the contrast from being lowered and to make the brightness in each wavelength component uniform. Also, in this liquid crystal projector, as in the first embodiment, the light of the complementary color component does not enter the respective color filters R, G, B of the color filter 18, and therefore the light of the respective color filters R, G, B is not generated. It is possible to prevent the loss and improve the color purity, and since the black matrix BM of the color filter 18 is not irradiated with light, it is possible to prevent the loss of light in the black matrix BM. , Light source 1
The utilization efficiency of light from 0 can be improved.

[Third Embodiment] Next, a third embodiment of the liquid crystal projector of the present invention will be described with reference to FIG. Also in this case, the same parts as those in the first embodiment shown in FIGS. 1 to 3 are designated by the same reference numerals, and the description thereof will be appropriately omitted. In this liquid crystal projector, the light from the light source 10 is made incident on the hologram 13 as parallel light through the reflector 11 vertically, and the liquid crystal display element 14 is composed of only the liquid crystal cell 17, and the liquid crystal cell 17 and the hologram 13 are arranged.
, That is, on the incident surface side of the liquid crystal cell 17,
It has a structure in which is arranged. The refraction element 21 includes pixels 17R, 17 for red, green, and blue of the liquid crystal cell 17, respectively.
This is a prism lens array in which a large number of unit prism lenses 21a corresponding to the unit pixels of G and 17B are arranged in a dot matrix. Each unit prism lens 21a
Means that when the lights of the respective wavelength components of red, green, and blue which are respectively separated by the hologram 13 are condensed toward the pixels of the corresponding colors of the liquid crystal cell 17, the lights of the respective wavelength components are directed in a substantially constant direction. Pixels 17 of each corresponding color of liquid crystal cell 17
The structure is such that the light is made to enter the R, 17G, and 17B substantially vertically.

In such a liquid crystal projector, the hologram 13 disperses the light of each wavelength component of red, green and blue into pixels 17R, 17G and 17 of the corresponding colors of the liquid crystal cell 17.
The light condensed toward B is suppressed from being diffused by the refraction element 21 disposed on the incident surface side of the liquid crystal cell 17 and refracted in a substantially constant direction, and is substantially distributed to the pixels of each corresponding color of the liquid crystal cell 17. Since the light is incident vertically, the optical characteristics of the liquid crystal are improved, the apparent aperture ratio can be increased, and since the light is emitted almost vertically from the liquid crystal cell 17, the spread of the light incident on the projection lens 16 is increased. Is small, the acceptance angle of the projection lens 16 can be suppressed to a small value, and thus the projection lens 16 can be formed small, and the difference in the incident angle between the respective wavelength components incident on the liquid crystal cell 17 becomes small. It is possible to prevent a decrease in contrast and make the brightness of wavelength components of each color substantially uniform. In addition, in this liquid crystal projector, the light of each wavelength component of red, green, and blue, which is separated by the hologram 13, is divided into pixels 17R, 17G, 17 of the corresponding colors of the liquid crystal cell 17.
Since it is incident on B, a color image can be enlarged and projected on the screen without the color filter 18.

[Fourth Embodiment] Next, a fourth embodiment of the liquid crystal projector of the present invention will be described with reference to FIG. Also in this case, the same parts as those in the first embodiment shown in FIGS. 1 to 3 are designated by the same reference numerals, and the description thereof will be appropriately omitted. In this liquid crystal projector, the light from the light source 10 is made incident on the hologram 13 as parallel light through the reflector 11 vertically, and the liquid crystal display element 14 is composed of only the liquid crystal cell 17, and the liquid crystal cell 17 and the hologram 13 are arranged.
, That is, on the incident surface side of the liquid crystal cell 17,
It has a structure in which is arranged. The refraction element 22 includes pixels 17R and 17R for red, green and blue of the liquid crystal cell 17, respectively.
This is a prism lens array in which a large number of micro prism lenses 22a corresponding to G and 17B are arranged in a dot matrix. Each micro prism lens 22a
Are the lights of the respective wavelength components of red, green, and blue, which are respectively separated by the hologram 13, are condensed toward the corresponding pixels 17R, 17G, and 17B for red, green, and blue of the liquid crystal cell 17, respectively. At this time, the light of each wavelength component is refracted in a substantially constant direction, and the pixel 17R of each corresponding color of the liquid crystal cell 17 is
The structure is such that the light is made to enter the 17G and 17B substantially vertically.

In such a liquid crystal projector, pixels 17R, 17G and 17 of corresponding colors of the liquid crystal cell 17 are split into light beams of red, green and blue wavelength components by the hologram 13.
The light condensed toward B is the micro prism lens 2 of the refraction element 22 arranged on the incident surface side of the liquid crystal cell 17.
The light is refracted in a substantially constant direction by 2a and is incident on the pixels 17R, 17G, and 17B of the corresponding colors of the liquid crystal cell 17 substantially vertically, so that the optical characteristics of the liquid crystal are improved as compared with the third embodiment. In addition to being able to increase the apparent aperture ratio, it is possible to suppress the spread of the light emitted from the liquid crystal cell 17 to be small, which reduces the spread of the light incident on the projection lens 16 The taking-in angle of the lens 16 can be suppressed to be small, and the difference in incident angle between the respective wavelength components incident on the liquid crystal cell 17 can be made smaller than that of the third embodiment, thereby improving the contrast. In addition, the brightness of the wavelength components of each color can be made substantially uniform. Further, in this liquid crystal projector, the light of each wavelength component of red, green, and blue, which has been spectrally separated by the hologram 13, is supplied to the pixel 17R of each corresponding color of the liquid crystal cell 17,
Since the light is incident on 17G and 17B, a color image can be enlarged and projected on the screen without the color filter 18.

[Fifth Embodiment] Next, a fifth embodiment of the liquid crystal projector of the present invention will be described with reference to FIG. Also in this case, the same parts as those in the first embodiment shown in FIGS. 1 to 3 are designated by the same reference numerals, and the description thereof will be appropriately omitted. In this liquid crystal projector, the light from the light source 10 is made incident on the hologram 13 as parallel light through the reflector 11 vertically, and the liquid crystal display element 14 is composed of only the liquid crystal cell 17, and the liquid crystal cell 17 and the hologram 13 are arranged.
, That is, on the incident surface side of the liquid crystal cell 17,
It has a structure in which is arranged. The refraction element 23 includes pixels 17R, 17 for red, green, and blue of the liquid crystal cell 17, respectively.
This is a prism lens array in which a large number of micro prism lenses 23a corresponding to G and 17B are arranged in a dot matrix. Each micro prism lens 23a
Is the light of the respective wavelength components of red, green, and blue, which are respectively separated by the hologram 13, are condensed toward the corresponding pixels 17R, 17G, and 17B for red, green, and blue of the liquid crystal cell 117. At this time, the light of each wavelength component is refracted in a substantially constant direction, and the pixel 17R of each corresponding color of the liquid crystal cell 17 is
The light is incident on 17G and 17B in a state close to vertical. In this case, the incident surface of each micro-prism lens 23 a has a pixel 17 of a corresponding color of the liquid crystal cell 117 according to each wavelength component of red, green and blue separated by the hologram 13.
R, 17G, and 17B are formed on the inclined surfaces having different angles. That is, the incident surface of the red micro-prism lens 23a corresponding to the red pixel 17R is
The incident surface of the green micro-prism lens 23a corresponding to the green pixel 17G has the largest inclination angle, and is formed with an inclination angle slightly smaller than the inclination angle of the incident surface of the red micro-prism lens 23a. The incident surface of the green micro-prism lens 23a corresponding to the green pixel 17B is formed with an inclination angle smaller than the inclination angle of the incident surface of the green micro-prism lens 23a.

In such a liquid crystal projector, each micro-prism lens 23a of the refraction element 23 arranged on the incident surface side of the liquid crystal cell 17 has each pixel pixel 1 of the liquid crystal cell 17.
7R, 17G, and 17B, and the incident surface of each microprism lens 23a corresponds to each color of the liquid crystal cell 117 according to each wavelength component of red, green, and blue dispersed by the hologram 13. Pixels 17R, 17G,
Each of the pixels 17B is formed on an inclined surface having a different angle, so that the hologram 13 splits the light into wavelength components of red, green, and blue, and the pixels 17 of the corresponding color of the liquid crystal cell 17 are dispersed.
The refraction element 2 reflects the light condensed toward R, 17G, and 17B.
Each of the micro prism lenses 23a of No. 3 refracts the light in a certain direction to make the pixel 17 of each corresponding color of the liquid crystal cell 17
It is possible to make the light incident on R, 17G, and 17B in a nearly vertical state. Therefore, the optical characteristics of the liquid crystal can be improved, the apparent aperture ratio can be increased, and the spread of the light emitted from the liquid crystal cell 17 can be suppressed to be smaller than that of the fourth embodiment. Therefore, the spread of the light incident on the projection lens 16 is reduced, the capture angle of the projection lens 16 can be suppressed to be small, and the difference in the incident angle between the respective wavelength components incident on the liquid crystal cell 17 can be reduced to the fourth value. It can be made smaller than that of the embodiment, the contrast can be further improved, and the brightness in the wavelength component of each color can be made substantially uniform. Further, in this liquid crystal projector, the light of each wavelength component of red, green, and blue, which has been spectrally separated by the hologram 13, is supplied to the pixel 17R of each corresponding color of the liquid crystal cell 17,
Since the light is incident on 17G and 17B, a color image can be enlarged and projected on the screen without the color filter 18.

In the third to fifth embodiments described above, the case where the liquid crystal display element 14 is composed of only the liquid crystal cell 17 has been described, but the present invention is not limited to this. You may comprise with the filter 18. By using the color filter 18 in this way, the color purity can be improved. Moreover, even if the color filter 18 is used, the loss of light due to the color filters R, G, B and the black matrix BM of the color filter 18 is small, and the utilization efficiency of the light from the light source 10 is improved, as in the first embodiment. be able to.

[0026]

As described above, according to the first aspect of the present invention, the light from the light source is separated into specific wavelength components by the hologra and is condensed on the pixels of the corresponding colors of the liquid crystal display element. The light emitted from each pixel of the liquid crystal display element is suppressed by the diffusion correction element and corrected in a substantially constant direction to reduce the spread of the light incident on the projection lens. The projection angle of the projection lens can be kept small, and even if there is a difference in the incident angle of each wavelength component incident on the liquid crystal display element, the diffusion correction element corrects the diffusion in a substantially constant direction. It is possible to reduce the difference in the incident angle between the respective wavelength components incident on the light source, thereby preventing the deterioration of the contrast and making the brightness of the respective wavelength components substantially uniform.

According to the seventh aspect of the present invention, when the light from the light source is separated into specific wavelength components by the hologra and condensed toward the pixels of the corresponding colors of the liquid crystal display element, the holograc and the liquid crystal are collected. The refraction element disposed between the display element and the liquid crystal display element refracts the light in a substantially constant direction toward the corresponding color pixel to cause the liquid crystal display element to enter the corresponding color pixel substantially vertically. In addition to improving the optical characteristics of the liquid crystal, it is possible to increase the apparent aperture ratio, and since the light is emitted almost vertically from the liquid crystal display element, it is possible to reduce the spread of the light incident on the projection lens. The angle of capture of light can be kept small, and the difference in the angle of incidence between the respective wavelength components that enter the liquid crystal display element can be reduced. It can be made substantially uniform brightness.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a first embodiment of a liquid crystal projector of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a plan view showing a correspondence relationship between the hologram of FIG. 1 and a color filter.

FIG. 4 is an enlarged view of a main part of a second embodiment of the liquid crystal projector of the present invention.

FIG. 5 is an enlarged view of a main part of a third embodiment of the liquid crystal projector of the present invention.

FIG. 6 is an enlarged view of a main part of a fourth embodiment of the liquid crystal projector of the present invention.

FIG. 7 is an enlarged view of an essential part of a fifth embodiment of the liquid crystal projector of the present invention.

FIG. 8 is a diagram showing an optical path state between a conventional hologram and a liquid crystal display element.

[Explanation of symbols]

 10 Light Source 13 Hologram 13a Unit Hologram 14 Liquid Crystal Display Element 15 Diffusion Correction Element 15a Unit Lens 16 Projection Lens 17 Liquid Crystal Cell 17R Red Pixel 17G Green Pixel 17B Blue Pixel 18 Color Filter R Red Filter G Green Filter B Blue Filter 20 Diffusion correction element 20a Microlens 21, 22, 23 Refraction element 21a Unit prism lens 22a, 23a Microprism lens

Claims (11)

[Claims] 1. A liquid crystal projector for irradiating a back surface of a liquid crystal display element with light from a light source, and enlarging and projecting an image displayed on the liquid crystal display element as a color image by a projection lens, the light source and the liquid crystal display element. A hologram that is disposed between the light sources and splits the light from the light source into specific wavelength components and focuses the light on pixels of corresponding colors of the liquid crystal display element to make the light incident substantially perpendicularly to the incident surface of the liquid crystal display element. And a diffusion correction element which is disposed in the liquid crystal display element and corrects diffusion of light of each wavelength component condensed by the hologram in a substantially constant direction, respectively. 2. The diffusion correction element has a structure in which a large number of unit lenses corresponding to a unit pixel composed of red, green and blue color pixels of the liquid crystal display element are arranged. The liquid crystal projector according to claim 1. 3. The liquid crystal projector according to claim 1, wherein the diffusion correction element has a structure in which a large number of microlenses corresponding to respective pixels of the liquid crystal display element are arranged. 4. The liquid crystal projector according to claim 1, wherein the liquid crystal display element is composed of only a liquid crystal cell, and the diffusion correction element is arranged on the exit side of the liquid crystal cell. . 5. The liquid crystal projector according to claim 1, wherein the liquid crystal display element includes a liquid crystal cell and a color filter. 6. The liquid crystal projector according to claim 5, wherein the diffusion correction element is provided between the liquid crystal cell and the color filter. 7. A liquid crystal projector for irradiating the back surface of a liquid crystal display element with light from a light source, and enlarging and projecting an image displayed on the liquid crystal display element as a color image by a projection lens, comprising: the light source and the liquid crystal display element. Between the hologram and the liquid crystal display element, the hologram being disposed between the hologram element and the hologram element for separating the light from the light source into specific wavelength components and condensing the light toward the pixels of each corresponding color of the liquid crystal display element. Placed in
A liquid crystal device, comprising: a refraction element that refracts light of each wavelength component separated and condensed by the hologram in a substantially constant direction and makes the light incident substantially perpendicularly to an incident surface of the liquid crystal display element. projector. 8. The refraction element has a structure in which a large number of unit prism lenses corresponding to a unit pixel composed of red, green, and blue pixels of the liquid crystal display element are arranged. The liquid crystal projector according to claim 7. 9. The liquid crystal projector according to claim 7, wherein the refraction element has a structure in which a large number of micro-prism lenses corresponding to respective pixels of the liquid crystal display element are arranged. 10. The incident surface of the micro prism lens is formed as an inclined surface having a different angle for each pixel of the liquid crystal display element according to each wavelength component dispersed by the hologram. The liquid crystal projector according to claim 9. 11. The liquid crystal display device comprises a liquid crystal cell only,
Alternatively, the liquid crystal projector according to claim 7, comprising a liquid crystal cell and a color filter.