JPH09189809A - Color filter and color image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color filter in which the utilization factor of lights become more advantageous in the projection type color display device of a reflection system and the color image display device utilizing the color filter. SOLUTION: S-polarized components concerning to respective colors of three- primary colors are diffracted and separated by a color filter 3 using a transmission type hologram to be converged on pixel electrodes 13r, 13g, 13b of the LDC panel 1 side of a special optical modulation part. However reflected lights becoming P-polarized components by being modulated by the optical modulation layer 16 of the LDC panel 1 side are made incident on the color filter 3, since the color filter 3 transmits the P-polarized components as they are, the transmission lights are used as projection lights. In the color filter 3, since the diffraction efficiency of the P-polarized components is suppressed to not more than 18% while diffracting the S-polarized components with the diffraction efficiency being near to 100%, the utilization factor of the lights and the contrast ratio are made higher than the case the projection lights are obtained by separating the modulated lights returning to a light source with a beam spritter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter and a color image display device applied to a system for image display and imaging, other image processing systems, etc., and more particularly to a reflection type color image display device. The improvement for improving the effective light utilization rate.

[0002]

2. Description of the Related Art Recently, there has been an increasing demand for a projection type display device for displaying an image on a large screen, such as a display for outdoor public use and control work, and a display for displaying high definition images such as high definition. ing. The projection type display devices are roughly classified into a transmission type and a reflection type.
In both systems, a spatial light modulator using an LCD (Liquid Crystal Display) panel is applied, and projection light is projected by making read light incident on the LCD panel and modulating the incident light in pixel units corresponding to video signals. It is designed to get light. Here, the LCD panel includes an active matrix substrate in which a switching element such as a thin film transistor and a pixel electrode whose potential is controlled by the switching element are arranged on a semiconductor substrate, and a common electrode coated on a transparent substrate (such as a glass substrate). A film and a liquid crystal layer sealed between the active matrix substrate and the common electrode film, and a potential difference between the common electrode film and each pixel electrode is changed for each pixel electrode according to a video signal, The read light is modulated by controlling the orientation of.

The difference between the transmissive method and the reflective method is that the former makes the active matrix substrate transparent and uses the transmitted light of the LCD panel as projection light, while the latter makes the pixel electrode of the active matrix substrate a reflective electrode or a dielectric. It is configured as an electrode for controlling the orientation of the liquid crystal through a body mirror film or the like, and the light reflected by the LCD panel is used as the projection light.
In general, the reflective method has a large aperture ratio in the liquid crystal cell portion because it does not need to provide a black stripe in the liquid crystal layer as compared with the transmissive method, and the heat generated due to absorption of read light is very small. A brighter image can be obtained while irradiating a large reading light.

By the way, conventionally, in a transmission type projection type color image display device, three transmission type LCD panels corresponding to three primary colors (R, G, B) and a three color synthesis optical system for synthesizing respective transmitted lights thereof. Although a color image was obtained by using, the size of the device increases and the manufacturing cost increases. Therefore, the transparent pixel electrodes for each color of the LCD panel are arranged in a stripe array, a mosaic array, or a delta array, and the array is supported. An apparatus has been proposed in which a color projection light can be obtained in one system by providing a single plate color filter in which filter elements of each color are arranged. Note that the filter elements for each color of the color filter are arranged adjacent to each other at different positions on the plane, but they form sub-pixels with a small area, and the light emitted from the adjacent R, G, B filter elements is Is viewed as one pixel that is a mixed color of each color. But,
In the device having such a configuration, of the read light (white light) that has passed through the LCD panel and entered the color filter, the light that passes through the color filter is only one of the three primary colors, and the other two colors. The ingredients will not be utilized. In addition, the transmittance of the color filter itself is low, and since the transmissive LCD panel has stripes as described above, the overall light utilization rate of the display device is extremely low.

Therefore, in connection with the spatial light modulator of the transmission type projection type color image display device, a color filter using a transmission type hologram has been proposed (JP-A-2-500).
937, JP-A-6-308332). First, an example of the spatial light modulator disclosed in Japanese Patent Laid-Open No. 6-308332 is shown in FIG.
A color filter 52 composed of a transmission hologram is arranged opposite to the LCD panel 51, and the color filter 52 diffracts the read light incident by the diffraction / spectral function of the transmission hologram into R, G, and B components. The light is dispersed and condensed on the transparent pixel electrodes 51r, 51g, 51b of the corresponding color of the LCD panel 51. Here, in the transmission hologram of the color filter 52, the unit hologram 52p is formed in an array shape at the same pitch as the arrangement pitch of the set of the transparent pixel electrodes 51r, 51g, 51b on the LCD panel 51 side. 52p is R,
The wavelength bands of G and B are focused on the transparent pixel electrodes 51r, 51g and 51b with different diffraction angles. Therefore,
With this configuration of the spatial light modulator, it is possible to realize a projection type color image display device that uses incident light without waste.

On the other hand, Japanese Patent Laid-Open No. 2-500937 discloses a transmissive hologram using a color filter composed of a holographic lens array and a transmissive method similar to that described above. A modulator is also disclosed. FIG. 28 shows an example of the spatial light modulator related to the reflection method.
Is shown in In the figure, 61 is a color filter having three layers of holographic lens array, 62 is a glass substrate,
Reference numeral 63 is a reflective LCD panel. LCD panel
63 is a transparent common electrode film 64, a liquid crystal layer 65, a reflective film 66, R, G,
Pixel electrode layer 67 in which pixel electrodes 67r, 67g, 67b according to B are arranged
The pixel electrodes 67r, 67g, 67 have a laminated structure.
In b, an electric potential is applied by an electron beam or a control light beam scanned from behind the LCD panel 63.
The color filter 61 includes a holographic lens array 61r that diffracts only the R color component of the read light, and a holographic lens array 61g that diffracts only the G color component.
Holographic lens array 61 that diffracts only the B component
b is stacked, and each array 6
1r, 61g, 61b holographic lens has pixel electrodes 67r, 67g, 67
The pitch is three times the pitch of b.

In this spatial light modulator, the virtual lens of each holographic lens array 61r, 61g, 61b diffracts the read light to diffract only the color component associated with that array, and the corresponding pixel arranged on the optical axis of each lens. Focus on the electrodes 67r, 67g, 67b. Although the constituent regions of the respective lenses overlap, the lenses of the respective arrays 61r, 61g, 61b diffract only the corresponding wavelength band components of the read light, so that only the R color component is diffracted in the array 61r, and G, The B component is transmitted, only the G color component is diffracted by the array 61g and the B component is transmitted, and the B color component is diffracted by the array 61b. As a result, the holographic lens array
The R, G, and B component lights diffracted by 61r, 61g, and 61b are the liquid crystal layer 6
5 and is reflected by the reflection film 66 corresponding to the area of each pixel electrode 67r, 67g, 67b and again enters the array 61r, 61g, 61b, but in the meantime, the liquid crystal layer 65 undergoes modulation in pixel units. The modulated component lights are re-incident on the lenses of the arrays 61r, 61g, 61b, re-diffracted by the lenses, and returned to the light source direction of the readout light.

[0008]

Generally, in a hologram, in order to increase its diffraction efficiency (the ratio of the light intensity of the first-order diffracted light to the light intensity of the incident reproduction illumination light), the reference light used when the hologram is created is used. It is necessary to increase the angle formed by the object light. Therefore, in the spatial light modulator of Japanese Patent Laid-Open No. 2-500937, when making each holographic lens of the color filter 61, the angle (θ) formed by the reference light and the object light is set large, and the read light is transmitted to the color filter 61. On the other hand, the incident angle is θ.

Although not explicitly disclosed in Japanese Patent Laid-Open No. 2-500937, according to the spatial light modulator, the modulated R, G,
Since each component light of B returns to the light source direction of the reading light, the polarization beam splitter is required for the reading light incident optical system as the entire configuration of the color image display device. That is, the read light is transmitted through the polarization beam splitter to the color filter 61.
The modulated light that has entered the lens and is returned through the color filter 61 is separated by the polarization beam splitter, and the separated modulated light is projected on the screen by the projection lens. However, if a polarization beam splitter is interposed in the incident optical system, the contrast ratio is greatly reduced due to its angular dependence and the light utilization rate is also reduced, and the cost of the entire device is increased because the polarization beam splitter itself is expensive. Invite.

On the other hand, when the diffraction efficiency of the hologram is examined, as the bend angle (the angle formed by the incident light and the diffracted light) becomes smaller, the P-polarized component of the diffracted light (the polarized component having a vibrating surface parallel to the incident surface) It is confirmed that the difference in the diffraction efficiency of the S-polarized component (polarized component having a vibrating plane perpendicular to the incident plane) becomes large. Generally, the diffraction efficiency η of a transmission hologram has a dependency on the modulation amount Δn of the refractive index, the thickness t, and the incident angle θ, but the incident angle θ is 60 ° to 9 °.
Under a large setting such as a range of 0 °, as shown in FIG. 29, the diffraction efficiency ηp of the P polarization component and the diffraction efficiency ηs of the S polarization component are functions F (Δn, t) with Δn and t as variables. )
With respect to the change of, there is a tendency of periodic change having mutually different phases. Then, with Δn and t kept constant, the incident angle θ
When 0 approaches 0, the phase related to the diffraction efficiency ηp of the P-polarized component approaches the phase related to the diffraction efficiency ηs of the S-polarized component, and θ =
At 0, both diffraction efficiencies theoretically match. Therefore, in the changes of the diffraction efficiencies ηp and ηs shown in FIG. 29, for example, the incident angle θ is set to 75 °, the conditions of Δn and t are selected, and the value of the function F (Δn, t) is set to the point A. By doing so, the diffraction efficiency ηs of the S-polarized light component can be set to about 18% while the diffraction efficiency ηs of the S-polarized light component is set to the maximum of 100%.

Therefore, the present invention focuses on the characteristics of the diffraction efficiency with respect to each polarization component in the hologram, and provides an optimum color filter for a color image display device. It was created for the purpose of providing a color image display device which does not require a beam splitter and can obtain a high contrast ratio.

[0012]

A first aspect of the present invention is a color filter using a hologram, which diffracts / splits incident light into a plurality of lights having different wavelength bands, and the diffracted / split wavelength bands. Of the S-polarized light component of the S-polarized light component while the diffraction efficiency of the S-polarized light component of the hologram is substantially maximized with respect to the incident light of the desired incident angle. A color filter having a characteristic that a difference between a diffraction efficiency and a diffraction efficiency of a P-polarized component is 30% or more, and mainly diffracting / splitting an S-polarized component and condensing it on a corresponding color pixel. .

The present invention relates to the color filter itself. Based on the diffraction characteristics of the hologram shown in FIG. 29, if the incident angle of the incident light is set relatively large, such as 60 ° or more and less than 90 °, the difference between the diffraction efficiency of the S-polarized component and the diffraction efficiency of the P-polarized component becomes It is possible to make it 30% or more,
Further, when the thickness t of the hologram and the modulation amount Δn of the refractive index are experimentally examined and adjusted, the above-mentioned values are set while setting the diffraction efficiency of the S-polarized component to almost 100% as shown at point A in FIG. It is also possible to make the difference in diffraction efficiency 80% or more. When performing spatial light modulation in a color image display device, one polarization component is discarded and the other polarization component is used as projection light in order to obtain a high contrast ratio regardless of whether it is a transmission method or a reflection method. Thus, the degree of separation between the S-polarized component and the P-polarized component can be increased to enable efficient operation. In the present invention, the S-polarized component is mainly diffracted.
The reason for spectral separation is as follows. According to FIG. 29, under the condition that the hologram thickness t is set large, P
It is also possible to diffract the polarization component mainly and suppress the diffraction of the S polarization component. However, in the transmission hologram, when the thickness t is increased, the angle selectivity (dependence of the diffraction efficiency on the incident angle of the incident light) and the wavelength selectivity (the incident angle of the incident light are made the same as the reference light at the time of forming the hologram). Then, the dependence of the diffraction efficiency on the wavelength of the incident light becomes high), and it becomes difficult to strictly set the incident angle and the wavelength of the incident light. Therefore, the color filter of the present invention that can reduce the thickness t of the hologram is easier to apply to the color image display device.

A second invention is a light source which emits readout light,
A spatial light modulation section including at least a color filter using a hologram, a light modulation layer, and a reflection layer, an incident optical system that causes the reading light emitted from the light source to enter the spatial light modulation section, and the space. In a reflection type color image display device having a projection optical system for projecting the readout light modulated by a light modulation element onto a screen, a hologram of a color filter of the spatial light modulator changes to incident light of a predetermined incident angle. On the other hand, while the diffraction efficiency of the S-polarized component is almost maximized, the difference between the diffraction efficiency of the S-polarized component and the diffraction efficiency of the P-polarized component is 30% or more.
It is configured to diffract and split a polarized component into a corresponding color pixel, and the incident optical system causes the reading light to enter the color filter at the predetermined incident angle.
The color filter diffracts / splits the read light and selectively focuses the light in each wavelength band on the corresponding color pixel position of the reflective layer, passes through the light modulation layer, and is reflected by the reflective layer. Of the light that has passed through the light modulation layer and is incident on the color filter again, the projection optical system projects on the screen a polarization component that is modulated by the light modulation layer and is transmitted without being diffracted by the color filter. The present invention relates to a color image display device.

The present invention relates to the configuration of the entire device when the color filter of the first invention is applied to the spatial light modulator of a reflection type color image display device. In this color image display device, by applying the above-mentioned color filter, it is possible to allow the S-polarized component to be incident on the modulation layer side with substantially the maximum diffraction efficiency while suppressing the diffraction of the P-polarized component of the readout light to be small. it can. Then, the S-polarized light component diffracting the read light becomes a P-polarized light component according to the modulation degree of the modulation layer, but since the color filter mainly diffracts the S-polarized light component, it re-enters the color filter from the reflective layer. The P-polarized light component to be transmitted is transmitted through the color filter except for the diffraction efficiency of the P-polarized light component of the color filter, and the P-polarized light component which is the modulated light can be directly extracted from the color filter as projection light. Therefore, it is possible to display a color image with a high light utilization rate and a good contrast ratio without the need for a polarization beam splitter. The P-polarized light component that first enters the color filter and is not diffracted is transmitted as the 0th-order light at the incident angle and is emitted in a direction unrelated to the modulated light. The P-polarized light component diffracted corresponding to the diffraction efficiency and incident on the side of the modulation layer becomes the S-polarized light component according to the degree of modulation, but the original P
Since the diffraction efficiency for the polarized component is suppressed, the influence on the projected image can be reduced. Further, the influence can be easily eliminated by providing a polarizing means for allowing only the P-polarized component to pass on the projection optical system side.

A third invention is a light source which emits readout light,
A spatial light modulator including at least a color filter formed of a holographic lens array, a light modulation layer, and a reflection layer, an incident optical system for causing the read light emitted from the light source to enter the spatial light modulator, and In a reflection type color image display device including a projection optical system that projects the readout light modulated by the spatial light modulator onto a screen, each holographic lens causes the readout light to enter a color filter at a predetermined incident angle. , S polarization component or P polarization component (hereinafter, referred to as “first polarization component”).
The polarization efficiency of the first polarization component and the other polarization component (hereinafter,
The difference in the diffraction efficiency of the "second polarization component") is 30% or more, and is configured to mainly diffract and split the first polarization component and focus it on the corresponding color pixel. And
When the incident optical system causes the reading light to be incident on the color filter at the predetermined incident angle, the center of each holographic lens and the center of the color pixel surface corresponding to each holographic lens are viewed at a predetermined distance. A planar relative position of the color filter and the reflective layer is set in a shifted state, and the light diffracted / split by each of the holographic lenses is condensed at the center of the corresponding color pixel surface, and the light modulation layer is formed. Of the light that has passed through the above and is reflected by the reflective layer and again passes through the light modulation layer and enters the color filter, a polarization component that is modulated by the light modulation layer and is transmitted without being diffracted by the color filter. The present invention relates to a color image display device in which the projection optical system projects the light onto a screen.

According to the second aspect of the present invention, the diffraction efficiency of the P-polarized component of the color filter among the P-polarized components re-incident from the reflective layer to the color filter is prevented from returning to the incident optical system side. Then, it relates to a measure for improving the light utilization rate. Generally, a color filter using a hologram is configured as a virtual holographic lens array regardless of whether it has a single plate structure or a laminated structure, and each holographic lens diffracts / splits readout light to a corresponding color pixel surface. Focus. Then, as seen in the diffraction characteristics of FIG. 28, each holographic lens is mainly S
It has the property of diffracting the polarized light component, but diffracting the P polarized light component at a small rate. By the way, when each holographic lens collects the diffracted S-polarized light component in the approximate center of each color pixel surface on its optical axis, the condensed light beam and the divergent light beam related to the P-polarized light component after being modulated by the reflection layer are The optical path is
It has symmetry with respect to the optical axis. Therefore, the diffraction condition of the color filter matches the divergent light flux that is the P-polarized light component, and the P-polarized light component that should originally be the projected light returns to the light source direction through the incident optical system based on the law of light reversal. , The light utilization rate will decrease. Therefore, in the present invention, the condensing light flux diffracted by each holographic lens is made to enter the corresponding color pixel of the reflective layer at a constant angle, and the re-incident optical path of the reflected light to the holographic lens is set. It is intended to improve the light utilization rate by keeping the diffraction conditions out of conformity with each other and using all the modulated P-polarized components for projection light. As is apparent from the above principle, the present invention is not limited to the case where the color filter mainly diffracts / splits the S-polarized component as in the second invention, but the reverse polarized component is mainly diffracted / splitted. It can also be applied to the case.

According to a fourth aspect of the present invention, a light source that emits the reading light, a polarization splitting unit that splits the reading light emitted from the light source into a first polarization component and a second polarization component, and the first invention.
A first incident optical system that makes the polarized light component of the second spatial light modulator enter the first spatial light modulator, a second incident optical system that makes the second polarized light component enter the second spatial light modulator, and the first incident optical system. And a projection optical system for synthesizing the modulated light of the first polarization component by the spatial light modulator and the modulated light of the second polarization component by the second spatial light modulator and projecting the combined light onto a screen. First
The spatial light modulator of is composed of at least a color filter using a hologram, a light modulation layer, and a reflection layer, and the read light incident at a predetermined incident angle by the color filter has almost the maximum diffraction efficiency of the first polarization component. However, the difference between the diffraction efficiency of the first polarized light component and the diffracted light rate of the second P polarized light component is set to 30% or more, and the first polarized light component is diffracted into the first, second, and third primary color lights. The light is split into light and selectively condensed at corresponding color pixel positions on the reflective layer, while the second spatial light modulator is an optical modulator that operates in synchronization with the first spatial light modulator. A layer and a reflective layer having a pixel array corresponding to the pixel array of the first spatial light modulator, wherein the first incident optical system converts the first polarization component to the predetermined one. The light is incident on the color filter of the first spatial light modulator at an incident angle. In addition, the second polarization component is caused to vertically enter the second spatial light modulator by the second incident optical system, and the first polarization component incident on the first spatial light modulator is Of the light that passes through the light modulation layer, is reflected by the reflection layer, passes through the light modulation layer again, and enters the color filter, modulated light that is modulated by the light modulation layer and is transmitted without being diffracted by the color filter, The projection optical system projects the second polarized light component that has entered the second spatial light modulation unit, passes through the light modulation layer, is reflected by the reflection layer, passes through the light modulation layer again, and is modulated. The present invention relates to a color image display device characterized by being synthesized and projected on a screen.

The present invention relates to the structure of an apparatus for displaying a color image by utilizing all the readout light emitted from a light source without waste. In the color image display device of the present invention, the reading light is separated into the first and second polarization components in advance by the polarization separation means, and the first polarization component is incident through the first incident optical system. In the spatial light modulator 1 of 1, the first polarization component is diffracted / split into each primary color light by using a color filter, modulated by each color pixel unit, and the second polarization component is vertically transmitted through the second incident optical system. In the second spatial light modulator incident on the optical system, the second polarized light component is modulated in each pixel without being diffracted / spectralized, and each modulated light by the first and second spatial light modulators is projected by the projection optical system. Combine and project on the screen. Therefore, in the second and third inventions described above, one polarization component of the readout light is discarded beforehand, but in the present invention, the polarization component can be used as the modulated light, and high-luminance, high-contrast ratio color light can be used. Images can be played.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a color filter and a color image display device of the present invention will be described in detail with reference to FIGS. <Embodiment 1> First, FIG. 1 is a sectional view schematically showing the structure of a spatial light modulator applied to a reflection type projection type color image display device. In the figure, 1 is an LCD panel, 2 is a thin glass layer, 3 is a color filter, 4 is a glass substrate, and 5 is a coupling prism. LC here
The D panel 1 includes a glass substrate or Si substrate 11 and the substrate 11
An active matrix drive circuit 12 formed above, a pixel electrode layer 13 in which pixel electrodes 13r, 13g, 13b that are selectively controlled and driven by the active matrix drive circuit 12 are regularly arranged, and a dielectric mirror film. 14 and the alignment film 15
And a light modulation layer 16 in which liquid crystal is sealed by a spacer and an alignment film 17
And a transparent common electrode film 18 are sequentially stacked.

Next, of the above-mentioned constituent elements, constituent elements other than those already described and the obvious ones will be described. The pixel electrodes 13r, 13g, 13b of the pixel electrode layer 13 are R, G,
Each of the sub-pixels corresponds to each color of B, and one set of these sub-pixels constitutes one pixel. The planar arrangement mode is shown in (A) to (C) of FIG. A mosaic arrangement, a stripe arrangement, or a delta arrangement is common, and in the case of the delta arrangement, a hexagonal close-packed arrangement as shown in FIG. 3 is often adopted. In this embodiment, the arrangement shown in FIG. 3 is adopted, and as shown in the figure, the pixels are aligned laterally in the order of R, G, B, and in plan view, the pixel electrodes 13r, 13g, 13b are Adjacent to each other. Further, between the pixel electrode layer 13 and the active matrix drive circuit 12,
A light shielding layer may be provided in order to prevent the readout light from entering the substrate 11 and generating photoconduction.

A liquid crystal having an operation mode such as TN mode, HFE mode, FLC mode, or DS mode can be applied to the light modulation layer 16, but the alignment films 15 and 17 are provided depending on the type of liquid crystal to be applied. This is omitted when a scattering type liquid crystal having a DS mode is used. The coupling prism 5 is composed of a flat glass plate,
One of the end faces is formed perpendicular to the incident direction of the read light, the end face serves as the read light incident face, and the upper side face serves as the projected light exit face. Further, although the glass substrate 4 is interposed between the coupling prism 5 and the color filter 3 in FIG. 1, they may be integrally configured, and in any case, the glass substrate 4 may be closely attached to the surface of the color filter 3. To be In FIG. 1, the thickness of the glass substrate 4 and the coupling prism 5 is thinner than that of the thin glass layer 2, but it is so drawn to clarify the structure and optical function of the device. In an actual device, the glass substrate 4 and the coupling prism 5 are generally thicker than the thin glass layer 2.

The color filter 3 is an important constituent element according to the present invention and will be described in detail. This color filter 3 is composed of a holographic lens array of a transmission hologram as in Japanese Patent Laid-Open No. 2-500937, and diffracts / splits incident light containing three primary colors of R, G and B for each primary color. Then, the corresponding pixel electrodes 13r, 13g, 13 of the LCD panel 1
It has the function of focusing light almost vertically to position b. That is,
The principal ray of the light flux is made to enter the pixel electrodes 13r, 13g, 13b substantially perpendicularly, and the light flux is caused by the lens action.
Focus on 13r, 13g, 13b. Strictly speaking, since the dielectric mirror film 14 is provided, light is condensed on the film (expressed as such in FIG. 1), but the film thickness of the dielectric mirror film 14 is Since the electrodes 13r, 13g, and 13b are extremely thin as compared with the size, the pixel electrodes 13r, 13g, and
This will be described as focusing on the surface of 13b.

The transmission hologram has a three-layer structure including an R holographic lens array layer 3r, a G holographic lens array layer 3g, and a B holographic lens array layer 3r. Each holographic lens array layer 3r, 3g, 3b has a holographic lens 3re, 3ge, 3be corresponding to a unit hologram arranged in a plane.
The optical axis of each holographic lens 3re, 3ge, 3be of each layer 3r, 3g, 3b is the corresponding pixel electrode 1 on the LCD panel 1 side.
It is positioned so as to pass through substantially the center of 3r, 13g, 13b. In the case of this embodiment, since each pixel electrode 13r, 13g, 13b adopts the hexagonal close-packed arrangement shown in FIG. 3, each holographic lens 3re, 3ge, 3be is also shown in FIG. It becomes an arrangement mode. That is, regarding the individual holographic lens array layers 3r, 3g, 3b, the holographic lenses are arranged at the same pitch as the vertical and horizontal pitches of the pixel electrodes for the respective corresponding colors, but three layers are stacked. When viewed in a plan view, the holographic lenses 3re, 3ge, 3be of the respective colors partially overlap each other, and the holographic lens of three colors corresponds to the pitch of the pixel electrode of one color.
3re, 3ge, 3be are in a positional relationship of being arranged at a pitch of 1/3.

By the way, each holographic lens array layer
The holographic lenses 3re, 3ge, and 3be corresponding to the unit holograms of 3r, 3g, and 3b are created so that the hologram mainly diffracts / splits the S-polarized component of the wavelength band associated with the corresponding color. And the characteristic is demonstrated using FIG. In the figure, as an example, the wavelength of the incident light is 540
nm, the modulation amount Δn of the refractive index with respect to the hologram light-sensitive material is 0.
03, and the diffraction efficiency of the P-polarized component was obtained by calculation under the condition that the hologram thickness t was set so that the diffraction efficiency of the S-polarized component was 100% at each bend angle. As is clear from this figure, when the bend angle is large, a characteristic of diffracting both the S-polarized component and the P-polarized component by almost 100% is obtained, and the bend angle is 12
When it is set to 0 ° or less, the diffraction efficiency of the P-polarized component can be set to 50% or less, and it can be set to 0% by approaching 90 °.

Further, the characteristic of the diffraction efficiency greatly depends on the wavelength of the incident light, but conversely, by utilizing the wavelength dependence, the S-polarized component becomes 100% with respect to the desired wavelength. It is also possible to perform an optimum design so that the diffraction efficiency of the P-polarized component is extremely small because the diffraction efficiency is close. Therefore, the color filter configured by the transmission hologram diffracts only the S-polarized component of each wavelength band for each color of R, G, B with high diffraction efficiency and P
It can be configured as a holographic lens array that suppresses the diffraction efficiency of the polarized component.

5 to 7, the bend angle is 75 °.
The relationship between the diffraction efficiency of each of the R, G, and B holograms and the wavelength of the incident light based on the optimum design condition in the above case is shown. In each figure, the solid line indicates the S-polarized component and the broken line indicates the P-polarized component. A diffraction efficiency of about 100% is obtained for the S-polarized component near the center wavelengths of R, G, and B, respectively. Is suppressed to about 18% or less.
When the color filter composed of the hologram having the characteristics shown in FIGS. 5 to 7 is used as the color filter 3 in FIG. 1, the incident angle θ of the read light with respect to the color filter 3 is 75 ° (= 180−105). ; Bend angle = 105 °), the holographic lenses 3re, 3ge, 3be for each color are S
Only the polarized component can be mainly diffracted, and the S polarized component can be vertically emitted to the pixel electrodes 13r, 13g, 13b side of the corresponding color.

The color filter in this embodiment
In 3, the holographic lens arrays 3r, 3g, and 3b, which have wavelength dependence in diffraction efficiency for each hologram sensitive material prepared for each of the R, G, and B spectral colors, are recorded for each spectral color and are stacked. Although the holographic lens array 3r, 3g, 3b having the wavelength dependence of the diffraction efficiency is similarly recorded to the single-plate holographic sensitive material may be multiple-recorded as described above. In that case, it is not necessary to mechanically align the layers, and a computer generated hologram or the like can be applied.

The readout light emitted from the light source (not shown) is coupled to the coupling prism 5 via the incident optical system (not shown).
Is incident vertically on the incident surface of the light, is transmitted through the coupling prism 5 and the glass substrate 4, and is incident on the color filter 3 at an incident angle of 75 °.
Is incident at. The read light incident on the color filter 3 is
First, the holographic lens array layer 3r for R color is spectrally diffracted. Each holographic lens 3re of the array layer 3r mainly diffracts only the S-polarized component of the light of the wavelength band relating to R color, and the components of other wavelength bands included in the read light and The P-polarized component in the wavelength band related to R color is transmitted as it is. In particular,
Each holographic lens 3re diffracts the S-polarized component with a diffraction efficiency close to 100% in the wavelength band related to the R color, while diffracting the P-polarized component under the condition that the diffraction efficiency is suppressed to 20% or less, and the diffracted light The R color pixel electrode 1 on the LCD panel 1 side located on the optical axis by the lens function
Focused light flux with 3r as the target. It should be noted that the P-polarized light component in the wavelength band relating to the R color is also slightly diffracted light and becomes a converging light beam like the S-polarized light component. Therefore, this array layer
Each holographic lens 3re of 3r makes a converging light beam composed of an S-polarized component related to the wavelength band of R color and a slight P-polarized component of the band perpendicularly incident on the holographic lens array layer 3g for G color, and The components other than the color wavelength band and the P-polarized component in the R color wavelength band that has not been diffracted are transmitted and made incident on the holographic lens array layer 3g for G color in the traveling direction of the read light.

Next, in the holographic lens array layer 3g for G color, since each holographic lens 3ge mainly diffracts only the S-polarized component of the light in the wavelength band relating to G color, Holographic lens array layer 3r for
While diffracting the S-polarized light component of the wavelength band related to the G color in the light transmitted through
LCD panel 1 which is diffracted under the condition that the diffraction efficiency of the polarized component is suppressed to 20% or less and is located on the optical axis of the lens 3ge.
The G-color pixel electrode 13g on the side is used as a target light beam. On the other hand, S related to the wavelength band of the R color that is vertically incident
A converging light beam composed of a polarized component and a slight P polarized component in the band is directly incident on the holographic lens array layer 3b for B color, and the holographic lens array layer for R color.
Of the light that has passed through 3r as it is, the components that are not subject to the diffractive action in this layer 3g (components other than the R and G color wavelength bands, the P polarization component in the R color wavelength band, and not diffracted) The P-polarized component of the G-color wavelength band) is also transmitted as it is, and is made incident on the holographic lens array layer 3b for B-color in the traveling direction of the reading light.

Next, since each holographic lens 3be of the holographic lens array layer 3b mainly diffracts only the S-polarized component of the light in the wavelength band of B color, R
Diffract the P-polarized component while diffracting the S-polarized component in the wavelength band relating to B-color in the light transmitted through each holographic lens array layer 3r, 3g for G and G with a diffraction efficiency close to 100%. The light is diffracted under the condition that the efficiency is suppressed to 20% or less, and the condensing light flux is targeted to the G-color pixel electrode 13b on the LCD panel 1 side located on the optical axis of the lens 3be. On the other hand, the vertically incident R and G converging light fluxes are directly emitted to the thin glass layer 2 and the two layers 3r among the light transmitted through the G color holographic lens array layer 3g as they are. , 3g was excluded from diffractive action (components other than R, G and B wavelength bands, R
The P-polarized component of the color bands of G and G, and the P-polarized component of the wavelength band of B that is not diffracted) are transmitted as they are and emitted to the thin glass layer 2 in the traveling direction of the reading light.

As a result of the above, from the color filter 3,
It is composed of an S-polarized component in the R-color wavelength band and a slight P-polarized component in each of the bands, and a converging light beam that targets the pixel electrode 13r, an S-polarized component in the G-color wavelength band and a slight P in each band. A converging light beam composed of a polarized light component, which is targeted at the pixel electrode 13g, an S polarized light component of the B color wavelength band and a slight P polarized light component of each band, and a converging light beam targeted at the pixel electrode 13b, and The 0th-order light including the components other than the wavelength band of each color and the P-polarized component of the wavelength band of each color is emitted.

The above-mentioned converging light fluxes (1) to (4) are incident on the LCD panel 1 through the thin glass layer 2, and then the common electrode film 18 is formed.
Through the alignment film 17, the light modulation layer 16, and the alignment film 15, the pixel electrode layer
The light is focused on the corresponding pixel electrodes 13r, 13g, 13b of 13 and the dielectric mirror film 14 on the surface of each pixel electrode 13r, 13g, 13b.
The reflected light is converted into a divergent light beam and re-enters the corresponding holographic lens 3re, 3ge, 3be of the color filter 3. However, a control voltage corresponding to a video signal that determines the state of one pixel in the active matrix drive circuit 12 is individually applied to each pixel electrode 13r, 13g, 13b, and the common electrode film 18
Since the liquid crystal of the light modulation layer changes the alignment state depending on the potential between the pixel electrodes 13r, 13g, 13b and the pixel electrodes 13r, 13g, 13b, the S-polarized components of the above-mentioned (1) to (3) are reciprocated between the color filter 3 and the LCD panel 1. The light is re-incident on the holographic lenses 3re, 3ge, and 3be after receiving the modulation corresponding to the control voltage. That is, when the modulation of X% is received, (100-X)
% Remains the S-polarized component, but X% becomes the P-polarized component and re-enters the holographic lens 3re, 3ge, 3be.

Then, the state is schematically shown in FIG. 8 for the S-polarized component in the G color wavelength band. The S-polarized light component diffracted by the holographic lens 3ge is condensed at substantially the center of the pixel electrode 13g on the optical axis of the lens. It is converted into a P-polarized component and enters the holographic lens 3ge. At this time, the modulated light beam re-enters the holographic lens 3ge via an optical path having a symmetrical relationship with the incident optical path to the pixel electrode 13g with respect to the optical axis. Although the incident angle and the reflection angle with respect to the pixel electrode 13g are shown large in FIG. 8, the angle is extremely small in reality because the holographic lens 3ge is minute.

By the way, as described above, the holographic lens 3ge diffracts the S-polarized light component of the incident light with a diffraction efficiency of approximately 100% and the P-polarized light component with a diffraction efficiency of approximately 20%, thereby omitting the pixel electrode 13g. It was a condensed light beam directed toward the center. Therefore, about 20% of the P-polarized light component that is re-incident after being modulated is diffracted by the holographic lens 3ge based on the law of optical reversal and returns to the direction of incident light (readout light), but other P-polarized light is returned. The component passes through the holographic lens 3ge as it is. Further, the above operation is the same for the R color and the G color. As a result, the P-polarized light components of each color obtained by the modulation pass through the color filter 3 as they are, and as shown in FIG. 1, pass through the coupling prism 5 from the glass substrate 4 and exit from the exit surface thereof. To be done. Then, the modulated light emitted from the emission surface of the coupling prism 5 is projected on the screen by a projection optical system (not shown). However, the S-polarized light component according to the modulation ratio and the S-polarized light component due to the modulation of the P-polarized light component in which the read light is diffracted by the color filter 3 directly pass through the color filter 3 as described later, but these are projected. It can be removed by providing a polarizing means on the optical system side that allows only the P-polarized component to pass.

On the other hand, the 0th order light travels through the thin glass layer 2 and is LC at an incident angle of 75 ° which is the same as the incident angle of the reading light.
The light enters the D panel 1 and is reflected by the dielectric mirror film 14 at a reflection angle of 75 °.
The holographic lens array layers 3r, 3g, and 3b of the holographic lens array layers 3r, 3g, and 3b that make up the color filter 3 are reflected by the holographic lens 3r and re-enter the color filter 3 at an incident angle of −75 °.
e, 3ge, and 3be do not have a diffraction characteristic with respect to the incident angle (−75 °), and the re-incident 0th-order light passes through the color filter 3 and passes from the glass substrate 4 to the coupling prism 5. The reading light is emitted from the end surface opposite to the incident surface.

In this embodiment, the case where the incident angle of the reading light with respect to the color filter 3 is 75 ° has been mainly described. Generally, the cross-sectional area S of the luminous flux of the reading light is
There is a relationship of Sr = Sa · cos θ between r and the irradiation area Sa to the color filter 3 and the incident angle θ. Since Sa is constant, Sr becomes extremely small as the incident angle θ increases, and the read light Lighting efficiency is reduced. In a projection type color image display device, it is desirable to irradiate read light as close as possible to parallel light in order to improve the contrast ratio and color reproducibility, but since the light source has a finite size, it is perfect. I can't get parallel light. Therefore, the read light cannot be efficiently narrowed down to a small area like the color filter 3, and the cross-sectional area S of the read light is
If r is made as large as possible, the utilization rate of illumination light will be large. However, "S that contributes to the projected light as much as possible
The diffraction angle of the P-polarized component is reduced while the diffraction efficiency of the polarized component is increased, and the incident angle θ of the readout light is increased to obtain a high contrast ratio while improving the light utilization rate. The conditions for increasing the illumination efficiency of the reading light are contradictory. In this embodiment, the incident angle θ is set to 75 ° as described above, but if it is set to 60 °, the illumination efficiency can be doubled. When the incident angle θ is set to 60 °, the condition of the diffraction efficiency is slightly reduced, but the quality of the display image is improved by improving the illumination efficiency of the reading light.
It was confirmed that the contrast ratio was better than that of the case of °. That is, considering the problem of the illumination efficiency of the reading light, the incident angle θ is rather 60 ° as the optimum condition.

<< Embodiment 2 >> In this embodiment, when the modulated P-polarized light component is emitted from the color filter 3 in the device of the first embodiment, a part of it returns to the light source direction of the readout light. Therefore, the present invention relates to an improvement for preventing the light utilization rate from decreasing. In FIG. 8, the light beam of the reading light is incident on the holographic lens 3ge, and then the S-polarized component is mainly diffracted at the incident point.
The light enters the pixel electrode 13g located on the optical axis of e substantially at the center thereof, and is modulated while reciprocating between the pixel electrode 13g corresponding to its reflection surface to become an S-polarized component corresponding to the degree of modulation. The light is re-incident on the holographic lens 3ge, but regarding each light ray, the re-incident point is a symmetrical position with respect to the optical axis of the holographic lens 3ge in relation to the incident point of the corresponding light ray of the reading light. Then, the incident direction with respect to the re-incident point coincides with the direction in which the light beam of the reading light is diffracted / spectralized when entering the re-incident point and is directed to the approximate center of the pixel electrode 13g.

By the way, as described in the first embodiment,
The holographic lens 3ge has a characteristic of diffracting the S-polarized light component of the readout light with a diffraction efficiency of almost 100%, but at the same time diffracting the P-polarized light component by approximately 20%. The light that is re-incident on the holographic lens 3ge is a P-polarized component corresponding to the modulation degree of the light modulation layer 16, and is the same as the polarized component that the holographic lens 3ge mainly diffracts the read light. As a result, at the above-mentioned re-incident point, an optimum diffraction condition for returning to the incident direction of the reading light is given to the re-incident of the P-polarized component which is the modulated light, and the P that should be originally the projected light. Nearly 20% of the deflection components are lost.
Further, in the region near the re-incident point, the similar condition is satisfied even if it is not the optimum condition, and the same phenomenon occurs. Then, the phenomenon similarly occurs in other holographic lenses 3re and 3be, and a part of the light that is emitted from the color filter 3 and can be used as projection light is lost, which naturally causes a reduction in the light utilization rate. .

Therefore, in this embodiment, each pixel electrode 13r, 1 corresponding to the center of each holographic lens 3re, 3ge, 3be.
The planar relative positions of the color filter 3 and the pixel electrode layer 13 are set in such a manner that the centers of the 3g and 13B are displaced by a certain distance when viewed in plan. Specifically, FIG. 9 shows the positional relationship between the holographic lens array 3g for G color and the pixel electrode layer 13. In the figure, the lens 3ge of the holographic lens array 3g
The center of the pixel electrode 13g corresponding to the center of the pixel electrode layer 13 is displaced by 1/2 of the size of the holographic lens 3ge.

Then, the holographic lens 3ge diffracts / splits the read light incident at the incident angle θ and focuses it on the center of the pixel electrode 13g. Therefore, the converging light flux is transmitted to the pixel electrode 13
Instead of being incident perpendicularly to the surface of g, as shown by the solid line with an arrow in FIG. 9, it is condensed as a constant inclined converging light beam at the center of the pixel electrode 13g and reflected at that center. Then, the divergent light beam becomes a divergent light beam as shown by the dotted line with an arrow.The divergent light beam becomes a light beam which is symmetrical with respect to the normal light beam passing through the center of the pixel electrode 13g and is adjacent to the holography. It will be incident on the lens 3ge '.

Therefore, according to this embodiment, the divergent light flux which is incident on the adjacent holographic lens 3ge 'is incident under the condition completely different from the diffraction condition for the read light of the holographic lens 3ge', and as a result, All of the divergent light flux will pass through the holographic lens 3ge '. If the plane relative positions of the color filter 3 and the pixel electrode layer 13 are set as described above, the same conditions are naturally satisfied for the R color and the G color.
It is possible to use all of the P-polarized component after the modulation that re-enters 3 as the projected light, and in principle it is possible to improve the light utilization rate by about 20% compared to the case of FIG. Further generalizing, even if the diffraction efficiency for the P-polarized component of the incident light in each of the holographic lenses 3re, 3ge, and 3be becomes large, the problem of the reduction of the light utilization rate, which is a problem in this embodiment, is not affected. It will be.

In FIG. 9, the divergent light beam reflected by the pixel electrode 13g is made incident on the adjacent holographic lens 3ge 'on the incident side of the reading light. However, as shown in FIG. It may be configured such that the characteristic light beam is incident on the adjacent holographic lens 3ge 'on the opposite side to the above, and in that case, the same effect is naturally obtained. In addition, in this embodiment, the holographic lens 3re shifts the centers of the lenses 3re, 3ge, 3be of the holographic lens arrays 3r, 3g, 3b and the centers of the corresponding pixel electrodes 13r, 13g, 13b of the pixel electrode layer 13 from each other. Although the description has been made under the condition that the size is 3 times the size of 3ge, 3be, a sufficient effect can be obtained if the size is selected in the range of 0.25 to 0.5 times. Furthermore, in this embodiment, the case where the color filter 3 mainly diffracts / splits the S-polarized component of the read light has been described.
From that principle, the present invention can be applied to those that mainly diffract and split the P-polarized component.

<Third Embodiment> The overall configuration of the color image display device described in the first and second embodiments has a light source which emits readout light with a spatial light modulator as a center.
An incident optical system that causes the read light to enter the spatial light modulator and a projection optical system that projects the modulated light emitted from the spatial light modulator onto the screen are arranged. Then, the projection optical system does not require a polarizing beam splitter like the conventional color image display device of JP-A-2-500937,
Since only a projection lens with a small image circle is sufficient, it is possible to project an image with a highly accurate projection lens.

However, when the modulated P-polarized light component is used as the projection light, the S-polarized light component according to the modulation ratio and the S-polarized light component due to the modulation of the P-polarized light component diffracted by the read light by the color filter 3 are 0. As the next light, the light passes through the color filter 3 and is emitted in the same direction as the P-polarized light component after modulation to reduce the contrast ratio of the image.

Therefore, in this embodiment, as shown in FIG. 11, a polarizing plate 21 for passing only the P-polarized component is attached to the exit surface of the coupling prism 5 of the spatial light modulator 20,
The S-polarized component is prevented from being mixed in the projected light, and the P-polarized component passing through the polarizing plate 21 is projected on the screen 23 by the projection lens 22. In the spatial light modulator described in the second embodiment, the emission angle of the P-polarized component slightly tilts.
Similarly, attach the polarizing plate 21 and attach the projection lens 22
Parallel tilting may be performed with.
Note that, as shown in FIG. 13, a polarizing beam splitter 24 may be attached instead of the polarizing plate 21 to separate the S-polarized component and only the P-polarized component may be incident on the projection lens 22.

Further, although each of the above measures is taken on the side of the projection optical system, it is possible to take measures on the side of the incident optical system as well, and a polarizing plate is provided in the incident light path of the read light to the spatial light modulator 20. The same effect can be obtained by providing a polarization beam splitter or a polarization beam splitter and limiting the read light to only the S polarization component in advance. In the above description, the case where the P polarization component is used as the projection light has been described, but this embodiment can also be applied to the case where the S polarization component is used as the projection light. In that case, the polarization characteristics of the polarizing plate and the polarization beam splitter are It's just the opposite.

<Fourth Embodiment> As described in the first embodiment, each holographic lens array 3r, 3 corresponding to three primary colors is used.
The characteristics of the diffraction efficiency with respect to the wavelength of the incident light of g and 3b are shown in FIGS. 5 to 7, respectively. However, those characteristics are for the case where the incident light is a perfect parallel light flux, and if not, each characteristic curve exhibits a broad tendency, and R, G, B
The wavelength bands in which the diffraction efficiency of the respective colors becomes large partially overlap in the vicinity of the boundary. Then, in that case, the color purity of the projected image is lowered, resulting in the deterioration phenomenon of the reproduced image.

As a countermeasure, it is effective to insert a filter for attenuating the light component in the wavelength band corresponding to the above-mentioned boundary region into the incident optical system. Specifically, as shown in FIG. 14, R, G, and B are arranged in the incident light path to the spatial light modulator 20.
Each dichroic mirror 25r, 25g, 25b corresponding to each color of
Is provided, and the read light is reflected by the mirror and is incident on the incident surface of the coupling prism 5 of the spatial light modulator 20.
Each of the dichroic mirrors 25r, 25g, 25b reflects the component light of the wavelength band related to the corresponding color of the light incident at the incident angle of 45 ° at the reflection angle of 45 ° and transmits the light of other wavelength bands. Each mirror 25r, 25g, 25b
Are stacked and arranged in parallel. The dichroic mirrors 25r, 25g, 25b may have a structure in which dielectric films are deposited in multiple layers on the surface of a glass substrate.

FIG. 15 shows the dichroic mirror 25r,
An example of the spectral characteristics when the band is limited by 25g and 25b is shown, and the wavelength bands for each color of R, G, and B are completely divided. Even if the light flux is not a parallel light flux, it is possible to suppress a decrease in color purity in the spatial light modulator 20. Also, dichroic mirror 25r, 25g, 25
Since the characteristic of b can be adjusted freely by changing the dielectric material, the film thickness, and the total number of films, the emission wavelength distribution characteristic of the light source and the wavelength-diffraction efficiency of the color filter 3 of the spatial light modulator 20 can be adjusted. It can be optimized in consideration of characteristics and desired color reproduction characteristics. Although the reflection type dichroic mirror is used in this embodiment, an incident optical system using a transmission type dichroic filter may be used.

Next, in connection with the above-mentioned problem of color purity, when strict color separation is required as the color filter 3 of the spatial light modulator 20, the holographic lens arrays 3r, 3 for each color are used.
A slight increase in diffraction efficiency outside the wavelength bands of the corresponding colors in g and 3b poses a problem. Here, when the wavelength-diffraction efficiency characteristics of FIG. 5 to FIG. 7 are examined, the diffraction efficiency decreases as the wavelength deviates from the wavelength at which the diffraction efficiency becomes maximum, and further deviates, and conversely the diffraction efficiency increases and small waviness (side Robe) is appearing.

By the way, it is generally known that the incident angle α and the diffraction angle β of a hologram have the following relationship. sin α + sin β = λ / p (1) where λ is the wavelength of the incident light, and p is the period of the diffraction grating. Based on this equation (1), if the incident angle α and the period p of the diffraction grating are fixed values, It can be understood that the sine of the bending angle β and the wavelength λ have a linear relationship, and the light diffracted by the holographic lens arrays 3r, 3g, 3b has different diffraction angles depending on the wavelength. Therefore, if these characteristics are used in reverse, the light within the wavelength band related to the corresponding color of the diffracted light of the holographic lens array of a certain color is focused on the pixel electrode of the corresponding color, and at the same time as the side lobe described above. It is also possible to condense light outside this band onto the pixel electrodes for other colors including that wavelength band, and prevent deterioration in color purity and achieve excellent color reproducibility.

Therefore, a specific method for improving the color reproducibility will be described with reference to FIG. 16 which focuses on the light incident on the holographic lens 3ge for G color. In the figure,
The distance between the holographic lens array 3g for G color and the pixel electrode layer 13 is set as Lg satisfying or approximating the following formula (2) or (3). Lg = Pc / tan | βbc | (2) Lg = Pc / tan | βrc | (3) where Pc is the pitch of pixel electrodes βbc is the diffraction angle at the center wavelength in the wavelength band of B color βrc is the R color Angle at the center wavelength in the wavelength band of, and the diffraction angle at the center wavelength in the G color wavelength band β
rc is 0 °. That is, the focal length of the holographic lens array 3ge for G color is set to substantially match Lg.
The distances between the other R-color and B-color holographic lens arrays 3r and 3b and the pixel electrode layer 13 can be similarly determined. However, the color filter used in the first embodiment
Since 3 is a laminated structure of the holographic lens arrays 3r, 3g, 3b, basically, the distance is set based on any color. As a result, each color holographic lens
Diffracted light in the wavelength band corresponding to the side lobes appearing in the wavelength-diffraction efficiency characteristics of 3re, 3ge, and 3be can be focused on the pixel electrode for the color including that band, and the deterioration of color purity can be rationalized. It becomes possible to prevent it and to improve the light utilization rate.

<Embodiment 5> In the color image display device according to each of the above embodiments, the color filter of the spatial light modulator is used.
The read light is incident at a large incident angle in the range of 60 ° to less than 90 ° with respect to 3. In that case, the optical distance from the light source is greatly different between the area on the incident side of the read light and the area far from the incident side in the color filter 3, and it is possible to make the illumination intensity of the incident light uniform over the entire surface of the color filter 3. Have difficulty. There is a problem that shading occurs in the image on the screen due to the nonuniformity of the light amount. Also, if the output of the light source is increased to suppress shading,
The size of the effective light emitting point of the light source becomes large, and it becomes inevitable that it becomes difficult to narrow down the luminous flux of the reading light by the incident optical system.

Therefore, in this embodiment, a deflection hologram for deflecting incident light is used in the incident optical system, and the optical distance from the light source to each region of the color filter 3 is made uniform to solve the above problem. FIG. 17 shows an example of the specific configuration. In this configuration example, in the spatial light modulator 20, instead of the coupling prism 5 as shown in FIG. 1, a flat glass substrate 26 that is in close contact with the color filter 3 or the glass substrate 4 and continuously extends laterally 26 Is provided, and the deflection hologram 27 is closely attached to one surface thereof.

The deflection hologram 27 is formed on the glass substrate 26.
The reading light vertically incident from the other surface of is reflected and diffracted at the diffraction angle γ, and the reading light diffracted at the diffraction angle γ passes through the inside of the glass substrate 26 and is incident on the surface of the color filter 3 at the incident angle θ. It is supposed to be incident at. In this case, since the light incident on the color filter 3 is once folded back by the deflection hologram 27, the optical distance from the light source (not shown) is substantially uniform in any region of the color filter 3, resulting in The problem of shading that occurs in the projected image can be reasonably solved.

Further, when the wavelength of the read light from the light source changes, the diffraction angle γ in the deflection hologram 27 changes, but as a reference state, the diffraction angle γ of the deflection hologram 27 and the incident angle θ to the color filter 3 are made equal. In other words, since the incident angle θ also changes according to the change of the diffraction angle γ, it is possible to prevent the diffraction angle β of the color filter 3 from changing as a result. That is, there is an advantage that the diffraction angle β by the color filter 3 can be compensated for the read light from the light source having a wide wavelength band.

By the way, in the fourth embodiment, the distance Lg between the color filter 3 and the pixel electrode layer 13 is determined based on the change in the diffraction angle corresponding to the wavelength band. There is a problem that the thickness becomes very thin and assembly becomes difficult. Also, each holographic lens 3re, 3ge, 3 of the color filter 3
NA of be becomes large, and corresponding pixel electrodes 13r, 13g, 13b
Since the divergence of the light flux reflected by becomes large, a projection lens 22 of the projection optical system must have a large image circle and high precision, and the light utilization rate may decrease. However, each holographic lens 3re, 3ge,
When the influence of the side lobe on the color reproducibility in the wavelength-diffraction efficiency characteristic of 3be can be ignored, the deflection hologram 27 can compensate the wavelength dependence of the diffraction angle of each holographic lens 3re, 3ge, 3be. , The degree of freedom in determining the distance Lg between the color filter 3 and the pixel electrode layer 13 can be secured, and accordingly, each holographic lens 3re, 3ge, 3be
Since it is possible to reduce the NA, the light utilization rate can be maintained high as a result. Further, if the NA is reduced, it is possible to prevent the contrast ratio and the light utilization rate from decreasing due to the angle dependency even when the polarization beam splitter 24 is provided on the projection optical system side as shown in FIG. You can

In this embodiment, a reflection type hologram is used as the deflection hologram 27, but a transmission type deflection hologram may be applied. In that case, the read light from the light source is transmitted type deflection hologram. Is directly incident on the glass substrate 26, and the diffracted light is incident on the glass substrate 26 and guided to the color filter 3. Of course, even if a transmission type deflection hologram is used, the compensation function related to the above wavelength dependency can be realized, but a transmission type hologram with a large bend angle has a relatively large wavelength dependency of the diffraction efficiency, and the Its diffraction efficiency tends to decay rapidly as it deviates from the wavelength. Therefore, a transmission type deflection hologram may be applied in the case of readout light from a light source that can obtain sufficient light intensity in a narrow wavelength band, but in general, a reflection type hologram has higher diffraction in a wider band. When using a xenon lamp, a metal halide lamp, a halogen lamp, or the like, which can exhibit efficiency and is usually used as a light source, it is desirable to apply a reflection type deflection hologram. The deflection hologram used in this embodiment is either a laminated hologram of R, G, and B colors, or a single-plate recorded hologram, like the color filter 3 described in the first embodiment. It may be.

<Embodiment 6> In this embodiment, in the incident optical system, a color image display device in the case of combining the structure of Embodiment 5 with the read light band limiting means described in Embodiment 4 and Regarding various deformations and improvements. First, the overall configuration as an example is shown in FIG. In the figure, the glass substrate 26 is closely attached to the spatial light modulator 20, the deflection hologram 27 is attached to the glass substrate 26, and the read light is incident on the color filter 3 of the spatial light modulator 20. Is the same as. In this example, the white light emitted from the light source 28 is converted into a parallel light flux by the collimator lens 29, the direction of the parallel light flux is converted by the mirror 30, and the dichroic mirrors 25r, 25r for the three primary colors R, G, B are converted.
After entering the 25g and 25b and limiting the wavelength band of each color light with the spectral characteristics shown in Fig. 15, the polarization beam splitter
It is incident on 31 to separate only the S-polarized component, and the S-polarized component is incident on the deflection hologram 27 via the glass substrate 26. Therefore, according to this example, in the incident optical system, [parallelization of light from the light source 28], [limitation of wavelength band of each color] and [limitation to required polarization component] are performed, and The optical distance between each area of the color filter 3 of the spatial light modulation unit 20 and the spatial light modulation unit 20 is made uniform, the diffraction / spectroscopic and modulation in the spatial light modulation unit 20 function ideally, and the light utilization rate is improved. High quality color images with high contrast ratio and color purity can be obtained.

By the way, since the diffraction angle at the deflection hologram 27 differs depending on the wavelength of the incident light, when the distance between the deflection hologram 27 and the color filter 3 of the spatial light modulator 20 is large, the deflected diffracted light is reflected by the glass substrate 26. There is a problem in that the color filter 3 is too wide to be efficiently irradiated with the color filter 3. However, that problem can be solved by implementing the following improvements and measures. (a) Focusing on the wavelength dependence of the diffraction angle of the deflection hologram 27,
As shown in FIG. 19, the dichroic mirrors 25r, 25g, 25b for the respective colors, which are the band limiting means, are arranged with a slightly larger distance, and the luminous flux in each wavelength band of R, G, B diffracted by the deflection hologram 27 is efficiently transmitted. Well illuminate the color filter 3. (b) The deflection hologram 27 is composed of a single unit for each of the R, G, and B wavelength bands, and as shown in FIG.
27g, 27b are separated from the glass substrate 26 and closely contacted,
The read light from the light source 28 is previously split into R, G, and B colors, and the split light is made incident on the corresponding deflection holograms 27r, 27g, and 27b via the glass substrate 26, and the respective deflection holograms. 27r, 27g, and 27b are incident on the color filter 3 at different diffraction angles. (c) The deflection hologram 27 is formed into a laminated structure, and as shown in FIG. 21, the lights having the central wavelengths of the R, G, and B wavelength bands are incident on the color filter 3 so that they are diffracted at substantially the same angle. (d) When the modulation amount Δn of the refractive index of the deflection hologram 27 is small, the diffraction wavelength band is narrowed when the incident angle of the incident light is 0 °, so that a large number of holograms are stacked and R as shown in FIG. The stack structure is such that each wavelength band of G, B is covered by the diffraction characteristics of a plurality of holograms. In that case, the diffraction angles are set to be the same in each wavelength band where the diffraction efficiency has a peak.

The surface of the deflection hologram 27 does not necessarily have to be parallel to the color filter 3. By tilting the surface of the deflection hologram with respect to the color filter 3 so that the bend angle becomes small, or by tilting the incident angle from 0 °, the wavelength band in which the deflection hologram 27 exhibits high diffraction efficiency is widened. Adopting various means is also effective in realizing efficient irradiation.

Further, as another example, as shown in FIG. 23, a deflecting prism can be used in the incident optical system.
The relatively wide light beam emitted by the light source 28 and collimated by the collimator lens 29 is incident on the deflecting prism 32, and is refracted twice by the deflecting prism 32, whereby the coupling prism 5 of the spatial light modulator 20. A narrow light beam is created according to the incident surface of. According to this example,
The width of the light flux is adjusted by the deflection prism 32, and the light source 28
The optical distances from the to the respective areas of the color filter 3 become relatively uniform, and the above-mentioned shading phenomenon occurring in the projected image is suppressed. However, the refraction angle of the deflection prism 32 changes depending on the wavelength, but the amount of change is smaller than that of the deflection hologram 27, and therefore the expansion of the diffraction angle due to the wavelength cannot be completely compensated.

<Embodiment 7> In this embodiment, the read light is separated into two polarization components, each polarization component is individually modulated by a color signal and a luminance signal using two types of spatial light modulators, and The present invention relates to a color image display device that synthesizes each component after modulation,
It is possible to obtain an image of high brightness and high contrast ratio with a light utilization rate that is completely useless. The basic configuration of the device is shown in FIG.
(A) in the figure mainly shows the separation system for the polarization components, the modulation system by the color signal and the combined system of each modulated light, and (B) in the figure.
Corresponds to a side view of (A), and mainly shows each modulation system by a color signal and a luminance signal, a combined system of modulated light, and a projection optical system. In the figure, the white light emitted from the light source 28 is collimated by the collimator lens 29, and is made incident on the dichroic mirrors 25r, 25g, 25b applied in the fourth embodiment, and the wavelength band of each color of R, G, B. Is limited. The light reflected by the dichroic mirrors 25r, 25g, 25b enters a polarization beam splitter 33 as a prepolarizer, and is separated into S polarization component and P polarization component by the polarization beam splitter 33.

Then, the separated S-polarized light component is made incident on one spatial light modulator 20 having substantially the same configuration as that described in the fifth embodiment. However, the glass substrate 26 of the spatial light modulator 20 is configured to be laterally longer than in the case of the fifth embodiment, and the S incident vertically on the glass substrate 26 is formed.
The polarization component is incident on the deflection hologram 27 that is in close contact with the lower surface side of the substrate 26 and is diffracted, and the diffracted light is reflected once inside the glass substrate 26 and enters the color filter 3. The S-polarized component that is incident on the color filter 3 and diffracted is diffracted / split into each of the R, G, and B color components based on the configuration and function of the spatial light modulator described in the first embodiment, and then in pixel units. A P-polarized component corresponding to the degree of the modulation is received by the glass substrate 26 and is emitted as a color-modulated light. However, in this device, the emitted color-modulated light enters the polarization beam splitter 34 for combining the polarization components. The non-modulated S-polarized component or the like corresponding to the degree of modulation is blocked by the polarizing plate 21 interposed between the glass substrate 26 and the polarizing beam splitter 34, and only the modulated P-polarized component is polarized beam splitter 34. It is designed to be incident on.

On the other hand, the P-polarized light component separated by the polarization beam splitter 33 goes straight and is reflected by the direction changing mirror 35, and the polarization beam splitter for synthesizing the polarization components is provided on the optical path of the reflected light. It can be incident on 34,
The polarization beam splitter 34 makes the incident P-polarized component incident on the other spatial light modulator 36 by the polarization splitting surface.
In contrast to the spatial light modulating section 20 including the color filter 3, the spatial light modulating section 36 is basically composed of a light modulating layer and a pixel electrode layer, and the pixel electrode layer has the above-mentioned Pixel electrodes are arranged in such a manner that one pixel is formed for the adjacent R, G, and B color pixel groups of the spatial light modulator 20 of FIG. 1, and each pixel electrode is driven in synchronization with a luminance signal. To be done. Therefore, the P-polarized light component incident on the spatial light modulator 36 is intensity-modulated and is emitted again to the polarization beam splitter 34 as brightness-modulated light.

As a result, the color-modulated light (P-polarized component) from the spatial light modulator 20 and the brightness-modulated light (P-polarized component) from the spatial light modulator 36 are incident on the polarization beam splitter 34. The beam splitter 34 combines the modulated lights on the same optical axis on the polarization splitting surface, and emits the combined light to the projection lens 22 side. Then, the projection lens projects the combined light on the screen 23. According to the color image display device of this embodiment, both polarization components included in the read light from the light source 28 are used to obtain color-modulated light and luminance-modulated light, respectively, and the modulated light is combined to project light. Since it is generated, it becomes possible to display an image with high brightness and high contrast ratio, together with the characteristics of the spatial light modulator 20 to which the color filter 3 by hologram is applied. In the above description, the S-polarized component of the white light emitted from the light source 28 by the polarization beam splitter 33 is incident on the spatial light modulator 20 side, and the P-polarized component is incident on the spatial light modulator 36 side. However, in principle, the polarization components may have the opposite relationship. However, in that case, in the spatial light modulator 20, as the color filter 3, the pixel electrodes 13r, 13g, 13 related to the corresponding color of the pixel electrode layer 13 are mainly obtained by diffracting / splitting the P-polarized component.
It is applied that the light is condensed to b and the S-polarized component is transmitted as it is, and the polarizing plate 21 that is adapted to pass only the P-polarized component is applied.

By the way, in the above-mentioned color image display device, in order to achieve the matching in the image structure by the color modulated light and the brightness modulated light in the polarization beam splitter 34 for synthesizing the polarization components,
The reading light diffracted by the deflection hologram 27 is read by the glass substrate 26.
After being reflected once inside, the light is incident on the color filter 3. However, because of this, the optical path length between the deflection hologram 27 and the color filter 3 becomes long, and the color filter 3
There arises a problem that the irradiation efficiency of the reading light with respect to is deteriorated.

Therefore, if the configuration shown in FIG. 25 is taken as a countermeasure, the above problem can be rationally solved. According to the configuration shown in the figure, the S polarization component separated by the polarization beam splitter 33 is converted into the P polarization component by the 1/2 wavelength plate 41. Then, a transmission type deflection hologram 42 which mainly diffracts the S-polarized component in the direction of 75 ° is closely attached to the upper surface of the glass substrate 26, and the P-polarized component obtained by the 1/2 wavelength plate 41 is Although it enters the deflection hologram 42, the P-polarized component is not diffracted because the diffraction conditions do not match, and passes through the deflection hologram 42 as it is. Meanwhile, glass substrate
On the lower surface of the 26 facing the half-wave plate 41, a quarter-wave plate 43 and a mirror 44 are closely attached in a laminated state, and the polarization hologram 42 and the glass substrate 26 are transmitted. The polarization component is reciprocated through the quarter-wave plate 43 to generate S
It is converted into a polarized component.

Therefore, when the S-polarized component after the conversion is transmitted through the glass substrate 26 and re-incident on the deflection hologram 42 from the inside, this time, it is diffracted by the deflection hologram 42 at a diffraction angle of 75 ° and is diffracted. The S-polarized component is transmitted through the glass substrate 26 and directly incident on the color filter 3. As a result, as is clear from FIG. 25 (A),
The distance between the deflection hologram 42 and the color filter 3 is greatly reduced, and efficient illumination of the color filter 3 is possible.

Further, as a countermeasure for the above, a structure of a color image display device as shown in FIG. 26 can be adopted. This configuration is an application of a part of the method applied to the device of the sixth embodiment, in which the S-polarized component separated by the deflecting beam splitter 33 is refracted twice by the deflecting prism 45, and the color filter of the spatial modulating unit 20. A light beam having a narrow width is incident on the incident surface of the coupling prism 5 at a predetermined angle of incidence required for 3. Similar to the configuration shown in FIG. 25, the optical path length of the incident optical path to the color filter 3 can be shortened, the distance to each region of the color filter 3 can be equalized, and shading may occur in the display image. It can be prevented.

As described above, in the device of this embodiment,
The spatial light modulator 20 includes a holographic lens array 3r, 3g, 3b.
Since there is a color filter 3 for diffracting / splitting the read light, it is necessary to make the read light into a light beam with a narrow width and make it incident. The light flux has a large cross-sectional shape in order to be incident on. By the way, if the light source 28 is a point light source, it is relatively easy to create a read light of a desired light flux by combining a lens and a prism as described above, but the actual light source 28 is not a point light source. (Because it has a finite size that cannot be ignored), it is not easy to secure high parallelism and uniformity of angular distribution while irradiating a small area with high efficiency. In particular, it is extremely difficult to separate the light flux of the single light source 28 into two polarization components, one of which has a large area and the other of which has a small area to be incident light. However, even if a highly accurate condition is imposed on, only the illumination efficiency and the uniformity which are considerably lower than that condition can be realized. However, also with respect to such a problem, a hologram plate having no lens action and only a deflection function is provided on the side of the spatial light modulator 36, and two beams having the same cross-sectional shape with different polarization components are created by the deflection beam splitter, Each spatial light modulator directly
When the light is made incident on 20,36, it is possible to provide read light having high uniformity and consistency with both.

[0073]

The color filter and the color image display device of the present invention have the following effects due to the above constitution. According to the invention of claim 1, S of reading light is S.
Provided is a color filter capable of suppressing the diffraction of the P-polarized component low while diffracting the polarized component with extremely high diffraction efficiency.
Particularly, it is applied to a projection type color image display device to improve the light utilization rate of the device. Further, there is an advantage that the hologram used for the color filter for mainly diffracting the S-polarized component can be made thin, and the desired effect can be obtained without setting the incident angle or wavelength of the incident light very strictly. . According to the invention of claim 2, in the color filter of claim 1, the diffraction condition and the illumination efficiency of the incident light are taken into consideration to provide the optimum condition for improving the contrast ratio and the color reproducibility. According to a third aspect of the invention, in the color filter according to the first or second aspect, when the incident light is diffracted / spectralized and condensed in a corresponding color pixel region, the color pixel regions are densely arranged. This makes it possible to provide a lens function with a large aperture ratio, and realizes a hologram-based color filter that is easy to manufacture and has high accuracy. Moreover, since the hologram having wavelength dependency is recorded and created, the optimization design is facilitated. According to the invention of claim 4, by applying the color filter of claim 1, claim 2 or claim 3 to the spatial light modulator, the modulated light to be the projection light does not return to the incident optical system of the reading light, Since the modulated light that passes through the color filter as it is can be used as the projection light, the polarization beam splitter, which was indispensable in the conventional reflection type color image display device, is not required in principle, and the high light utilization rate and good contrast ratio are achieved. It enables the display of various color images. According to the invention of claim 5, the color filter of claim 1, claim 2 or claim 3 mainly diffracts the S-polarized component and diffracts / splits the P-polarized component at a small ratio. When applied, the P-polarized component that should originally be the projected light returns to the incident optical system, but this is rationally solved to improve the light utilization rate. The present invention can also be applied to the case where the color filter principally diffracts and splits the P-polarized component in principle. The invention of claim 6 provides optimum conditions for obtaining the effect in the invention of claim 5. According to a seventh aspect of the present invention, a method of making the reading light incident on the spatial light modulator is simplified, and a small-sized spatial light modulator with a low manufacturing cost is realized. The inventions of claim 8 and claim 9 solve the problem that the polarized light component opposite to the polarized light component of the projected light is mixed in the projected light according to the modulation degree, and it is possible to display a color image with a high contrast ratio. To According to the tenth aspect of the present invention, the wavelength band relating to each spectral color of the readout light is limited in advance by the incident optical system, thereby making it possible to display a color image with high color purity. According to the eleventh to fourteenth aspects of the present invention, the optical distance between the light source and each region of the color filter is made uniform, and shading is prevented from occurring in the color image. The invention of claims 15 and 16 is directed to a spatial light modulator comprising a color filter having a diffraction / spectroscopic function with a hologram, a light modulation layer and a reflection layer, and a spatial light composed of only the light modulation layer and the reflection layer. Using the modulator, the former spatial light modulator creates color modulated light, the latter spatial light modulator creates brightness modulated light, and realizes a color image display device that synthesizes and projects the modulated light. It greatly improves the light utilization rate and enables the display of color images with high brightness and high contrast ratio. The invention of claim 17 is claim 15 or claim 1.
In the sixth aspect of the invention, it is possible to improve the color purity by the same principle as in the tenth aspect.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a structure of a spatial light modulator of a color image display device according to a first embodiment of the invention.

FIG. 2 is a diagram showing a basic arrangement mode of pixel electrodes.

FIG. 3 is a diagram showing a hexagonal close-packed arrangement of pixel electrodes and a planar positional relationship of holographic lenses corresponding to the respective pixel electrodes.

FIG. 4 shows the wavelength of incident light λ = 540 for a hologram.
nm and the modulation amount of the refractive index Δn = 0.03, the diffraction efficiency ηs of the P deflection component when the bend angle is changed while the diffraction efficiency ηs of the S deflection component is kept at 100% by changing the thickness t. It is a graph which shows change.

FIG. 5 is a graph showing diffraction efficiency characteristics of a P-polarized component and an S-polarized component in an incident light wavelength band of 400 nm to 700 nm for an R-color hologram created under an optimum design condition with a bend angle of 75 °.

FIG. 6 is a graph showing diffraction efficiency characteristics of a P-polarized component and an S-polarized component in a wavelength band of incident light of 400 nm to 700 nm for a G-color hologram created under optimal design conditions with a bend angle of 75 °.

FIG. 7 is a graph showing diffraction efficiency characteristics of a P-polarized component and an S-polarized component in a wavelength band of incident light of 400 nm to 700 nm for a B-color hologram created under an optimum design condition with a bend angle of 75 °.

FIG. 8 relates to the color image display device of the second embodiment,
When the center of the holographic lens for G color and the center of the corresponding pixel electrode of the corresponding color are seen in a plan view, the holographic lens for G color diffracts / splits the read light to make the S modulation component correspond to the pixel electrode of the corresponding color. FIG. 6 is a schematic diagram showing a process in which the P-polarized component after being condensed and reflected and modulated on the pixel electrode side and re-incident on the holographic lens is transmitted through the holographic lens to become projection light.

FIG. 9 is a diagram for explaining the characteristics of the color image display device according to the second embodiment, in which the read light is incident from the center of the pixel electrode of the corresponding color when the center of the holographic lens for G color is seen in a plan view. The holographic lens for G color diffracts and disperses the read light in a state in which it is displaced in the direction opposite to the side by a distance equivalent to 0.5 times the size of the holographic lens, and the S modulation component is converted to the pixel electrode of the corresponding color. FIG. 6 is a schematic diagram showing a process in which light is condensed, reflected / modulated on the pixel electrode side, re-incident on the holographic lens, and the P-polarized component after modulation is transmitted through the holographic lens and becomes projection light.

FIG. 10 is a diagram for explaining the characteristics of the color image display device according to the second embodiment, in which the read light is incident from the center of the pixel electrode of the corresponding color when the center of the holographic lens for G color is seen in a plan view. The holographic lens for G color diffracts and disperses the read light in a state in which the holographic lens is shifted to the side by a distance corresponding to 0.5 times the size of the holographic lens to focus the S modulation component on the pixel electrode of the corresponding color, FIG. 6 is a schematic diagram showing a process in which the P-polarized component after being reflected / modulated on the pixel electrode side and re-incident on the holographic lens is transmitted through the holographic lens to become projection light.

FIG. 11 is a related configuration diagram of a spatial light modulator and a projection optical system showing an improved example (addition of a polarizing plate) in the third embodiment.

FIG. 12 is a related configuration diagram of the spatial modulation unit and the projection optical system when the countermeasure of Embodiment 2 is taken in the improved example (addition of a polarizing plate) in Embodiment 3 (projection system in parallel tilt). Is.

FIG. 13 is a related configuration diagram of a spatial light modulator and a projection optical system showing an improvement example (addition of a polarization beam splitter) in the third embodiment.

FIG. 14 is a diagram showing a related configuration of an incident optical system, a spatial light modulator, and a projection optical system showing an improved example (addition of a dichroic mirror) in the fourth embodiment.

FIG. 15 is a graph showing spectral characteristics when a band is limited by a dichroic mirror.

FIG. 16: The holographic lens for G color diffracts and disperses the G wavelength band light to the pixel electrode for the G color, and collects the light in the wavelength band for the side lobe in the R and B colors. FIG. 6 is a schematic diagram showing a state in which the pixel electrode according to FIG.

FIG. 17 is a related configuration diagram of a spatial light modulator and a projection optical system showing an improved example (addition of a deflection hologram) in the fifth embodiment.

FIG. 18 is a related configuration diagram of an incident optical system, a spatial modulation unit, and a projection optical system showing an improved example (addition of a deflection hologram, a collimating lens, a dichroic mirror, and a polarization beam splitter) in the sixth embodiment.

FIG. 19 is a related configuration diagram of an incident optical system, a spatial modulator, and a projection optical system showing an improved example (arrangement of dichroic mirrors of R, G, and B with a large interval) in the sixth embodiment.

FIG. 20 is a related configuration diagram of a spatial modulation unit and a projection optical system showing an improved example (a deflection hologram for R, G, and B is separately arranged alone) in the sixth embodiment.

FIG. 21 is a related configuration diagram of a spatial modulation unit and a projection optical system showing an improved example of Example 6 (where a deflection hologram is laminated and R, G, and B spectra are diffracted at the same diffraction angle).

FIG. 22 is a graph showing wavelength-diffraction efficiency characteristics of a hologram having a stack structure.

FIG. 23 is a related configuration diagram of an incident optical system, a spatial modulation unit, and a projection optical system showing an improved example (incident of readout light using a deflection prism) in the sixth embodiment.

FIG. 24 is a configuration diagram of an incident optical system, a spatial modulator, and a projection optical system of a color image display device according to a seventh embodiment.
However, (B) is a view of (A) viewed from the side.

FIG. 25 is a related configuration diagram of an incident optical system, a spatial modulation unit, and a projection optical system showing an improved example (addition of a half-wave plate, a deflection hologram, and a quarter-wave plate / mirror) in the seventh embodiment. .. However, (B) is a view of (A) viewed from the side.

FIG. 26 is a related configuration diagram of an incident optical system, a spatial modulation unit, and a projection optical system showing an improved example (incident of readout light using a deflection prism) in the seventh embodiment. However, (B) is a view of (A) viewed from the side.

FIG. 27 is a simplified schematic diagram showing a configuration example of a transmission type projection color image display device disclosed in JP-A-6-308332.

FIG. 28 is a schematic diagram showing a configuration example of a reflection type color image display device disclosed in JP-A-2-500937.

FIG. 29 is a graph showing the modulation amount Δn of the refractive index of the hologram when the incident angle of the incident light is set large in the range of 60 ° to 90 °.
3 is a graph showing changes in the diffraction efficiency ηs of the S deflection component and the diffraction efficiency ηp of the P deflection component when the function F (Δn, t) with the thickness t as a variable is changed.

[Explanation of symbols]

1,51,63 ... LCD panel, 2 ... Thin glass layer, 3, 52, 61 ...
Color filter, 3r, 3g, 3b, 61r, 61g, 61b ... Each color (R, G,
Holographic lens array for B), 3re, 3ge, 3be ... each color
(R, G, B) holographic lens, 4, 26, 62 ... Glass substrate, 5 ... Coupling prism, 11 ... Glass substrate or Si substrate, 12 ... Active matrix drive circuit, 13, 67
... Pixel electrode layer, 13r, 13g, 13b, 67r, 67g, 67b ... Each color (R, G,
B) Pixel electrode, 14 ... Dielectric mirror film, 15, 17 ... Alignment film, 16, 65 ... Light modulation layer (liquid crystal layer), 18, 64 ... Common electrode film, 2
0,36 ... Spatial light modulator, 21 ... Polarizer, 22 ... Projection lens, 23
… Screen, 24,31,33,34… Polarizing beam splitter, 2
5r, 25g, 25b ... Dichroic mirror, 27,27 ', 27r, 27g, 2
7b, 42 ... Deflection hologram, 28 ... Light source, 29 ... Collimating lens, 30, 35, 44 ... Mirror, 32, 45 ... Deflection prism, 41 ...
1/2 wave plate, 43 ... 1/4 wave plate, 51r, 51g, 51b ... Transparent pixel electrode, 52p ... Condensing unit hologram, 66 ... Reflective film, Lp,
Lg ... Optical distance between the holographic lens and the dielectric mirror film coated on the surface of the pixel electrode layer, θ, α ...
Incident angle of reading light, βrc, βbc, γ ... Diffraction angle.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location G03B 21/00 G03B 21/00 D

Claims (17)

[Claims] 1. A color filter using a hologram, wherein incident light is diffracted / split into a plurality of lights having different wavelength bands, and the diffracted / split light in each wavelength band is selected to a corresponding color pixel position. In a color filter that focuses light selectively, the hologram shows the diffraction efficiency of the S-polarized component (hereinafter simply referred to as "S-polarized component") having a vibrating surface perpendicular to the incident surface with respect to incident light of a desired incident angle. While making it about the maximum,
The difference between the diffraction efficiency of the S-polarized light component and the diffraction efficiency of the P-polarized light component (hereinafter, simply referred to as “P-polarized light component”) having a vibrating surface parallel to the incident surface is 30% or more. A color filter characterized by diffracting / splitting a polarized component and condensing it on the corresponding color pixel. 2. When the incident angle of the incident light is about 60 °, the S efficiency of the S-polarized light component is maximized while the S-polarized component is maximized.
The difference between the diffraction efficiency of the polarization component and the diffraction efficiency of the P polarization component is 30.
The color filter according to claim 1, which has a characteristic of not less than%, and mainly diffracts / splits the S-polarized component and focuses it on a corresponding color pixel. 3. A hologram sensitive material prepared for each spectral color, a holographic lens array having wavelength dependence of diffraction efficiency is recorded for each spectral color, and each hologram sensitive material after recording is recorded. 3. The color according to claim 1 or 2, wherein a plurality of holograms are laminated, or a hologram sensitive material of a single plate is multiplexed and recorded with a hologram lens array for each spectral color having diffraction efficiency wavelength dependence. filter. 4. A light source for emitting read light, a spatial light modulator including at least a color filter using a hologram, a light modulation layer and a reflective layer, and read light emitted from the light source for the spatial light. In a reflection type color image display device comprising an incident optical system for entering a modulation section and a projection optical system for projecting the readout light modulated by the spatial light modulation element on a screen, a color filter of the spatial light modulation section. The hologram has a characteristic that the diffraction efficiency of the S-polarized component is approximately maximum with respect to the incident light of a predetermined incident angle, and the difference between the diffraction efficiency of the S-polarized component and the diffraction efficiency of the P-polarized component is 30% or more. The S-polarized light component is mainly configured to be diffracted / spectralized to be condensed on a corresponding color pixel, and the incident optical system outputs the read light at the predetermined incident angle to the color frame. The light is incident on a filter, the color filter diffracts / splits the readout light, selectively condenses the light of each wavelength band at the corresponding color pixel position of the reflective layer, passes through the light modulation layer, and Of the light that is reflected by the reflective layer, passes through the light modulation layer again, and enters the color filter, a polarization component that is modulated by the light modulation layer and transmitted without being diffracted by the color filter is projected onto the projection optical system. A color image display device characterized by projecting on a screen. 5. A light source that emits read light, a spatial light modulator that includes at least a color filter formed of a holographic lens array, a light modulation layer, and a reflective layer, and read light emitted from the light source. In a reflection type color image display device including an incident optical system for entering the spatial light modulator, and a projection optical system for projecting the readout light modulated by the spatial light modulator on a screen, each holographic lens has a predetermined Of the S-polarized light component or P
While the diffraction efficiency of one of the polarization components (hereinafter, referred to as “first polarization component”) is substantially maximized, the diffraction efficiency of the first polarization component and the other polarization component (hereinafter, referred to as “second polarization component”). The difference in the diffraction efficiency of "the polarized light component of") is 30% or more, and is mainly configured to diffract and split the first polarized light component to focus it on the corresponding color pixel, When the incident optical system causes the reading light to be incident on the color filter at the predetermined incident angle, the center of each holographic lens and the center of the color pixel surface corresponding to each holographic lens are viewed at a predetermined distance. A planar relative position of the color filter and the reflective layer is set in a shifted state, and the light diffracted / split by each of the holographic lenses is condensed at the center of the corresponding color pixel surface, and the light modulation layer is formed. Reflected by the reflective layer Of the light that has passed through the light modulation layer and is incident on the color filter again, the projection optical system projects on the screen a polarization component that is modulated by the light modulation layer and is transmitted without being diffracted by the color filter. A color image display device characterized by: 6. The amount of deviation between the center of each holographic lens when viewed two-dimensionally and the center of the color pixel surface corresponding to each holographic lens is 0.2 of the size of the holographic lens.
The color image display device according to claim 5, wherein the color image display device has a magnification of 5 to 0.5. 7. A flat plate-shaped coupling prism whose end face is formed perpendicularly to the incident direction of the reading light is brought into close contact with the surface of the color filter in the spatial light modulation section, and the end face of the coupling prism is used for reading the reading light. The color image display device according to claim 4, 5 or 6, wherein the flat plate portion has a surface serving as an incident surface and an exit surface for reading out light. 8. The incident optical system is provided with a first polarizing means for passing only a polarized component which the color filter of the spatial light modulator diffracts / splits with a greater diffraction efficiency, or /
The color image display device according to claim 4, claim 5, claim 6, or claim 7, wherein the projection optical system is provided with a second polarization unit that allows only a polarization component opposite to the polarization component to pass therethrough. 9. The color image display device according to claim 8, wherein the first and second polarizing means are polarizing plates. 10. The incident optical system is provided with band limiting means for limiting the wavelength band of light of each spectral color diffracted / split by the color filter of the spatial light modulator to a predetermined bandwidth. The color image display device according to claim 5, claim 6, claim 7, claim 8 or claim 9. 11. An incident optical system is provided with a second hologram for diffracting / deflecting incident light to make it incident on a color filter at a desired incident angle, so that the optical distance between the light source and each region of the color filter is uniform. The color image display device according to claim 4, claim 5, claim 6, claim 7, claim 8, claim 9, or claim 10 that has been converted into a color. 12. A holographic lens array having wavelength dependence of diffraction efficiency is recorded for each spectral color on each hologram sensitive material prepared for each spectral color, and each second hologram is recorded. Laminated hologram sensitive material,
12. The color image display device according to claim 11, wherein a holographic lens array for each spectral color having diffraction efficiency wavelength dependence is multiplexed and recorded on a single-plate hologram photosensitive material. 13. The color according to claim 11 or 12, wherein the holographic lens array for each spectral color in the second hologram is recorded so as to have substantially the same diffraction angle at each wavelength showing the maximum diffraction efficiency. Image display device. 14. The incident optical system is provided with a prism for diffracting / deflecting the reading light from the light source and for making the light incident on the color filter at a desired incident angle. Alternatively, the color image display device according to claim 10. 15. A light source for emitting read light, a polarization separating means for separating the read light emitted from the light source into a first polarization component and a second polarization component, and a first polarization component for the first polarization component. A first incident optical system that is incident on the spatial light modulator of
A second incident optical system that causes the second polarized light component to be incident on the second spatial light modulator, modulated light of the first polarized light component by the first spatial light modulator, and the second spatial light. The projection optical system is configured to combine the modulated light of the second polarization component by the modulator and project the light on the screen, and the first spatial light modulator includes at least a color filter using a hologram, a light modulation layer, and reflection. The read light, which is made up of layers, has a diffraction efficiency of the first polarization component and a diffraction efficiency of the second P polarization component of the read light which is incident at a predetermined incident angle while the diffraction efficiency of the first polarization component is substantially maximized. With a difference in light ratio of 30% or more, the first polarized component is diffracted / split into the first, second, and third primary color lights and selectively condensed on the corresponding color pixel position of the reflective layer. On the other hand, the second spatial light modulator is It has been constructed by the reflective layer having a pixel arrangement corresponding to the first spatial light modulator of the pixel array and the light modulating layer which operates in synchronism with the optical modulation unit, the first
The first optical component is made incident on the color filter of the first spatial light modulator at the predetermined incident angle by the incident optical system, and the second polarized component is caused by the second incident optical system. The first polarization component incident on the first spatial light modulation section is made incident vertically to the second spatial light modulation section, passes through the light modulation layer, is reflected by the reflection layer, and again enters the light modulation layer. Among the light that has passed through and entered the color filter, the modulated light that has been modulated by the light modulation layer and transmitted without being diffracted by the color filter, and the second polarization component that has entered the second spatial light modulator are It passes through the light modulation layer and is reflected by the reflection layer,
A color image display device characterized in that a projection optical system combines the modulated light that has passed through the light modulation layer and is modulated, and projects the combined light onto a screen. 16. A polarization synthesizing means for synthesizing the light modulated by the first spatial light modulator and the light modulated by the second spatial light modulator on the same optical axis by the projection optical system, and the light synthesizing by the polarization synthesizing means. 16. The color image display device according to claim 15, comprising a projection lens that projects light onto a screen. 17. The color image display device according to claim 15 or 16, further comprising band limiting means for limiting the wavelength bands of the light from the light source to the predetermined bandwidths of the first, second and third primary color lights. .