JP4910830B2 - Liquid crystal module and liquid crystal display device - Google Patents

Description

  The present invention relates to a liquid crystal module including three liquid crystal light valves that respectively modulate red light, green light, and blue light, and a liquid crystal display device using the same.

In a projection display device such as a liquid crystal projector, light emitted from a light source is separated into red, green, and blue, and each color light is modulated by three light valves composed of liquid crystal display elements. the light flux dichroic Lee Kkumira or dichroic Lee click mirror prism, and combined again, and enlarged and projected on a projection surface.

  As a light valve mounted on the above liquid crystal projector or the like, an active matrix liquid crystal display element driven by a thin film transistor (hereinafter referred to as TFT) is generally used. Most of the liquid crystal display elements of the active matrix drive system use nematic liquid crystal, and the main display system includes an optical rotation mode liquid crystal display element.

  The nematic liquid crystal used in the optical rotatory mode liquid crystal display element is a twisted nematic (TN type) liquid crystal having a 90 ° twisted molecular arrangement, which is in principle a black and white display and exhibits a high contrast ratio and good gradation display. .

  The two substrates on which the alignment films are formed are arranged so that the alignment films of the respective substrates are opposed to each other, and are bonded together with a sealing material around a display area where an image is actually displayed. Spacers for controlling the gap between the substrates are formed between the substrates, and liquid crystal is sealed to manufacture a liquid crystal cell. Note that the above-described liquid crystal is composed of several types of single liquid crystal materials and is also called a liquid crystal composition.

  Furthermore, the twist direction is made constant by adding an optical rotatory material called a chiral agent to the liquid crystal material. Thereafter, a polarizing plate is attached to the manufactured liquid crystal cell to manufacture a liquid crystal display element.

  As a technique for obtaining stable alignment in a display device using a TN type liquid crystal, Patent Document 1 defines a chiral pitch (twist pitch, a distance necessary for liquid crystal molecules to be twisted 360 °). Thereby, alignment defects such as reverse tilt and reverse twist can be prevented and good display can be obtained.

  In recent years, with the miniaturization of projection display devices such as liquid crystal projectors, liquid crystal light valves have also been miniaturized, and on the other hand, higher definition and higher brightness of pixels have progressed. As the definition becomes higher, the pixel pitch between liquid crystal display elements becomes smaller. Therefore, the range in which the light shielding portion is formed becomes narrower. For example, when the substrate size is 22.9 mm (0.9 inch) XGA (extended graphics array) type, the number of pixels is 1024 × 768 and the pixel pitch is 18 μm. It has become.

  Such narrow-pitch high-definition devices of 20 μm or less have problems such as the occurrence of alignment abnormalities due to TFT steps and lateral electric fields, and the following countermeasures have been considered for this problem.

(1) The gap is narrowed, that is, the cell gap is reduced, and the vertical electric field between the TFT array substrate and the counter substrate is strengthened to prevent the influence of the horizontal electric field.
(2) Increase the pretilt to reduce the influence of the transverse electric field (Patent Document 2).
(3) Definition of chiral pitch (twist pitch, distance required for liquid crystal molecules to be twisted 360 °) (Patent Document 1).

  In particular, in the three-plate type, in the case of green (= 550 nm), the visual recognition of the orientation abnormality is remarkable due to the characteristics of human eyes.

Japanese Patent Laid-Open No. 04-186227 Japanese Patent Laying-Open No. 2005-258086

  Here, a method of applying the measures (1) and (2) only to, for example, a green panel has been proposed. However, with this method, the process becomes complicated and becomes one of the causes of cost increase. In the measure (3), in a narrow-pitch device such as a projector, it is very effective against orientation abnormality to reduce the chiral pitch, that is, to increase the amount of chiral agent added. However, since the projector emits light, there is a concern about image quality deterioration due to material decomposition. In particular, blue (= 450 nm) on the low wavelength side is a problem.

  The present invention has been made to solve such problems. That is, the present invention is a liquid crystal module having three liquid crystal light valves that respectively modulate red light, green light, and blue light, and the liquid crystal light valves face a pair of substrates with a predetermined gap. The liquid crystal layer is sandwiched between the pair of substrates, and the liquid crystal layer of the liquid crystal light valve is composed of a liquid crystal material to which an optical rotatory substance is added. The content of the optical rotatory substance in is different.

  Specifically, in the liquid crystal module, the content of the optical rotatory substance in the liquid crystal light valve corresponding to blue light is less than the content of the optical rotatory substance in the liquid crystal light valve corresponding to green light.

  In the present invention, the display mode of the liquid crystal layer of the liquid crystal light valve is a twisted nematic mode. In addition, a spacer formed at a predetermined location is used to control the gap between the pair of substrates in the liquid crystal light valve. In addition, an inorganic material is also used as an alignment film formed on a pair of substrates in a liquid crystal light valve. In particular, the liquid crystal layer of the liquid crystal light valve has a refractive index anisotropy of 0.10 or more, and a gap between a pair of substrates is 4 μm or less.

  The present invention also includes a light source and a condensing optical system that separates light emitted from the light source into red, green, and blue light having different principal wavelengths and guides them to three liquid crystal light valves. A liquid crystal display device using the liquid crystal module as three liquid crystal light valves.

  In the present invention as described above, by changing the content of the optical rotatory substance in the three liquid crystal light valves, it is possible to achieve both improvement in light resistance and high contrast as the entire liquid crystal module using the three liquid crystal light valves. Will be able to.

  Further, by reducing the amount of optical rotatory substance added to the liquid crystal light valve for blue light to be less than the amount added to the liquid crystal light valve for green light, it is possible to prevent image quality degradation from material decomposition due to light. . In addition, it is possible to obtain high image quality by including the largest amount in a green light liquid crystal light valve, which has a remarkable alignment abnormality due to the characteristics of the human eye.

  Here, the liquid crystal material has a rod-like shape, and has a birefringence because the electron density is different between the molecular major axis direction and the minor axis direction. The difference between the refractive index in the major axis direction and the minor axis direction of the liquid crystal molecules is called refractive index anisotropy (hereinafter referred to as Δn). The product Δn · d of Δn and the cell gap (d) is called retardation, and indicates an optical path difference when light decomposed in two directions of the major axis and the minor axis passes through the liquid crystal layer.

For example, in a TN liquid crystal, in order to obtain the maximum transmittance characteristic, Δnd design based on the following formula is used. When a TN liquid crystal alignment cell is placed under crossed Nicols (transmittance T when TN alignment and voltage is OFF), T = 1− {sin ² [((1 + u ² ) ^1/2 × π / 2) ] / (1 + u ² )}, u = 2Δnd / λ, and when (1 + u ² ) ^1/2 = 2n, Max is reached. Further, Max is obtained when Δnd = (4n ² −1) ^1/2 × (λ / 2) (1st: Δnd = √3 × (λ / 2)).

  A narrow pitch high-definition device of 20 μm or less, such as a liquid crystal projector, has a problem such as occurrence of abnormal alignment due to a transverse electric field. As a countermeasure, a narrow gap, that is, a thin cell gap is used, and a TFT array substrate and a counter substrate It is effective to strengthen the vertical electric field and prevent the influence of the horizontal electric field.

  In order to obtain the maximum transmittance characteristic, it is necessary to increase Δn of the liquid crystal from the above formula when the above-described measures such as reducing the cell gap are taken. From the above formula, the maximum transmittance design for green light (550 nm) is Δnd = 0.48 μm. For example, when the cell gap is 4 μm, Δn = 0.12 is theoretically required. Even in these configurations, the effectiveness of the present invention can be exhibited.

  The present invention has the following effects. That is, it is possible to achieve both improvement in light resistance and high contrast as a whole liquid crystal module using three liquid crystal light valves, and it is possible to provide a liquid crystal display device with high image quality and high reliability.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view illustrating the configuration of a liquid crystal light valve applied to the liquid crystal module according to the present embodiment. FIG. 2 is a circuit diagram of an active matrix liquid crystal display element applied to the liquid crystal light valve. FIG. 3 is a schematic cross-sectional view of a pixel portion.

  As shown in FIG. 1, in the liquid crystal light valve, a pair of substrates (TFT array substrate 11 and counter substrate 12) are bonded with a sealing material 15 so as to face each other with a predetermined gap, and a liquid crystal layer 16 is interposed between the pair of substrates. It is something that is pinched.

  In the liquid crystal module of the present embodiment, this liquid crystal light valve is provided for each color light of red light, green light, and blue light, and the liquid crystal light valve corresponding to each color modulates according to the image display. Can be done.

  If the TFT array substrate 11 is a transmission type, for example, a quartz substrate, if it is a reflection type, for example, a substrate made of a silicon material, the counter substrate 12 is made of, for example, a glass substrate or a quartz substrate.

  In the case of a transmission type, the TFT array substrate 11 is provided with a pixel electrode 13 and is made of a transparent conductive thin film such as an ITO film (indium tin oxide film). In the case of the reflective type, for example, a reflective electrode made of a metal material is used. As the metal material, aluminum having a high reflectance in the visible range is generally used. More specifically, an aluminum metal film added with several wt% of copper or silicon is generally used. In addition, for example, platinum, silver, gold, tungsten, titanium, or the like can be used. The counter substrate 12 is provided with the counter electrode 14 made of the above-described entire surface ITO film on the front surface.

  Here, the configuration of the TFT array substrate 11 will be briefly described with reference to FIG. A plurality of pixel electrodes 13 formed in a matrix that forms an image display region of the liquid crystal display element are provided with pixel switching transistors 22 that perform switching control of the pixel electrodes 13 at adjacent positions.

  A data line 23 to which a pixel signal is supplied (see FIG. 2) is electrically connected to the source 24 of the transistor 22 described above, and supplies a pixel signal to be written to the data line 23. Further, the scanning line 25 is electrically connected to the gate of the transistor 22, and the scanning signal is applied to the scanning line 25 in a pulse manner at a predetermined timing.

  The pixel electrode 13 is electrically connected to the drain 26 of the transistor 22, and the pixel signal supplied from the data line 23 is transmitted at a predetermined timing by opening the switch of the transistor 22 that is a switching element for a certain period. Write.

  A pixel signal of a predetermined level written in the liquid crystal layer 16 through the pixel electrode 13 is held for a certain period with the counter electrode 14 formed on the counter substrate 12.

  The liquid crystal layer 16 modulates light and enables gradation display by changing the orientation and order of the molecular assembly according to the applied voltage level. In the case of normally white display, incident light can pass through the liquid crystal portion according to the applied voltage, and light having a contrast corresponding to the pixel signal is emitted from the liquid crystal display element as a whole.

  Here, in order to prevent the held pixel signal from leaking, an auxiliary capacitor 28 is added in parallel with the liquid crystal capacitor formed between the pixel electrode 13 and the counter electrode 14. Thereby, the holding characteristics are further improved, and a liquid crystal display element with a high contrast ratio can be realized. Further, in order to form such a storage capacitor, a resistance common wiring is provided.

To manufacture a liquid crystal display element, first, a high melting point metal (WSi in the present embodiment) is formed as a first light-shielding film on the TFT array substrate 11 made of quartz, and then as a first interlayer film. SiO ₂ is laminated, a polycrystalline silicon film (p-Si) 33 is formed by using a CVD (Chemical Vapor Deposition) method, and a pattern is formed by etching.

Thereafter, a gate insulating film is formed, a polycrystalline Si film (p-Si) is formed as a gate electrode, and a pattern is formed by etching to form a scanning line 25. Thereafter, SiO ₂ is laminated as a second interlayer film, and first contacts are formed as source and drain electrodes.

Then, a metal material (Al in the present embodiment) is formed as a first wiring film by film formation such as sputtering, and patterning is performed by etching. Thereafter, SiO ₂ is laminated as a third interlayer film to form a second contact, and then a metal film (Ti in this embodiment) is formed as a second light shielding film. Further, SiO ₂ is laminated as a fourth interlayer film to form a third contact, and ITO is formed as a transparent electrode.

  Here, the spacer for controlling the substrate gap of the liquid crystal display element is columnar. After applying PMER (manufactured by Tokyo Ohka Kogyo Co., Ltd.) to a thickness of 3 μm as a photoresist on a substrate on which a transparent resist layer serving as a columnar spacer has been formed, exposure treatment is performed by ultraviolet irradiation using a photomask. And then developing and baking to form columnar spacers.

  Next, the TFT array substrate 11 and the counter substrate 12 are cleaned. Next, alignment films 20 and 21 are formed on each substrate. For the alignment films 20 and 21, for example, an organic material made of polyimide is used. And it apply | coats with a spin coat so that a film thickness may be set to 50 nm, pre-bake with a hotplate, and post-bake is performed after that.

  Next, the alignment films 20 and 21 are rubbed to form a seal pattern formed except for the injection port, and a liquid crystal composition is injected. A liquid crystal composition having a refractive index anisotropy Δn at room temperature of 0.16 is used so that the transmittance of green light is theoretically maximized at a gap of 3 μm.

  In the liquid crystal material, a chiral agent shown in FIG. 4 is added. Here, in this embodiment, four types of samples of 1 wt%, 2 wt%, 5 wt%, and 10 wt% are prepared as the amount of addition of the chiral agent, and thereafter, by image quality evaluation and light resistance test in green light / blue light. Image quality degradation was evaluated. FIG. 5 shows the evaluation results. Although not shown in FIG. 5, the image quality evaluation for red light is the same as the image quality evaluation for green light.

  The evaluation results shown in FIG. 5 are sensory evaluation results when the liquid crystal light valve is projected with green light and blue light. The results of pattern display A (black and white gradation), B (moving image), and C (checkered pattern) were evaluated based on the overall score in 10-level evaluation for each pattern. 20 points or more, Δ mark indicates 15 points or more. In FIG. 5, the life ratio is the value of the light resistance of the liquid crystal light valve corresponding to blue light when the light resistance of the liquid crystal light valve corresponding to green light is 1. In the liquid crystal light valve corresponding to the green light, the light resistance is 1 when the amount of the chiral agent added is 1 wt% to 10 wt%.

  As in this embodiment, the amount of chiral agent added is less in the liquid crystal light valve corresponding to the blue light than the liquid crystal light valve corresponding to the green light. It is possible to achieve both good image quality that is not visually recognized and improved light resistance.

  That is, in the liquid crystal light valve corresponding to blue light, the light resistance (lifetime) is inferior as the addition amount of the chiral agent is increased. Therefore, the smallest addition amount that does not affect the image quality is selected. In the evaluation example shown in FIG.

  On the other hand, in the liquid crystal light valve corresponding to green light, although the light resistance is not changed up to 1 wt% to 10 wt% of the chiral agent, it is necessary to exceed 5 wt% in the image quality evaluation.

  In a liquid crystal module having three liquid crystal light valves corresponding to RGB, the overall life (light resistance) is determined by the life of the liquid crystal light valve corresponding to blue light, and the overall image quality is a liquid crystal light valve corresponding to green light. Determined by the image quality.

  Therefore, in order to achieve both a long life and high image quality for the entire liquid crystal module, the amount of chiral agent added to the liquid crystal light valve corresponding to blue light is the smallest value of 2 wt%, green, which does not deteriorate the image quality. In a liquid crystal light valve corresponding to light, the amount of chiral agent added may be, for example, 5 wt% which is not less than a value that does not deteriorate image quality.

  In addition, in the liquid crystal light valve corresponding to red light, it may be more than the amount of the chiral agent added to the liquid crystal light valve corresponding to green light. The value of the addition amount is an example when a chiral agent having the composition shown in FIG. 4 is used, and may be different for other chiral agents. However, it is preferable that the ratio of the chiral agent addition amount of the liquid crystal light valve corresponding to blue light and the chiral agent addition amount of the liquid crystal light valve corresponding to green light is approximately 1: 2.

  Next, as an example of an electronic apparatus using the above liquid crystal module, a configuration of a projection type liquid crystal display device will be described with reference to a schematic configuration diagram of FIG. In FIG. 6, the projection type liquid crystal display device 100 having a configuration using liquid crystal light valves 1010, 1013, and 1019 corresponding to each color of red (R), green (G), and blue (B) is shown.

  The liquid crystal module of the present embodiment has a module configuration that includes three liquid crystal light valves 1010, 1013, and 1019 for each color light of RGB as a minimum configuration. Other configurations such as lenses 109, 1012, 1018 and a cross prism 1020 may be included.

  In the projection type liquid crystal display device 100 shown in FIG. 6, the lamp 102 has a light emitting portion 102b disposed at the focal position of the reflector 102a, and the light emitted from the lamp 102 is substantially parallel to the optical axis of the reflector 102a. Light is emitted forward from the opening.

  In the subsequent stage of the lamp 102, an illuminated area (corresponding to an effective aperture for performing light modulation for pixel formation) formed by, for example, twisted nematic liquid crystal constituting liquid crystal light valves 1010, 1013, and 1019 described later. ), A plurality of lens cells having a similar outer shape substantially equal to the aspect ratio of, for example, a multi-lens array 103 arranged in a square and a plurality of lens cells so as to face the lens cells of the multi-lens array 103. And a multi-lens array 104 in which the lens cells are formed.

  The light condensed by the multi-lens arrays 103 and 104 is polarized into light having a predetermined polarization direction by the polarization conversion block 105. That is, the non-polarized light (P-polarized wave + S-polarized wave) emitted from the lamp 102 passes through the polarization conversion block 105, and thereby has a predetermined polarization direction (for example, P) corresponding to the liquid crystal light valves 1010, 1013, and 1019. Polarized light). The description of the polarization conversion block 5 is omitted.

A wave converted into, for example, a P-polarized wave by the polarization conversion block 105 is incident on the plano-convex lens 106 arranged at the subsequent stage of the polarization conversion block 105. The plano-convex lens 106 collects light from the polarization conversion block 105 and can efficiently irradiate the liquid crystal panels 1010, 1013, and 1019.

  The light emitted from the plano-convex lens 106, that is, white light, first enters the dichroic mirror 107 that passes through the red light R, passes through the red light R, and reflects the green G and blue light B. The red light R transmitted through the dichroic mirror 107 is guided by the mirror 108 to the liquid crystal light valve 1010 through the convex lens 109 with the traveling direction being bent by 90 °, for example.

  On the other hand, the green light G and the blue light B reflected by the dichroic mirror 107 are separated by the dichroic mirror 1011 that transmits the blue light B. That is, the green light G is reflected and guided to the liquid crystal light valve 1013 through the convex flat lens 1012. In addition, the blue light B passes through the dichroic mirror 1011 and travels straight, and is guided to the liquid crystal light valve 1019 through the reflex lens 1014, the mirror 1015, the refu lens 1016, the mirror 1017, and the convex flat lens 1018.

  Each color light light-modulated by the liquid crystal light valves 1010, 1013, and 1019 enters the cross prism 1020, respectively. For example, the cross prism 1020 is formed by bonding a plurality of glass prisms. Interference filters 1021a and 1021b having predetermined optical characteristics are formed on the joint surfaces of the glass prisms. For example, the interference filter 1021a is configured to reflect red light R and transmit green light G.

  The interference filter 1021b is configured to reflect the blue light B and transmit the green light G. Therefore, the red light R is reflected by the interference filter 1021a and the blue light B is reflected by the interference filter 1021b in the direction of the projection lens 1022. Then, the green light G reaches the projection lens 1022 by passing through the interference filters 1021a and 1021b, where each color light is combined into one optical axis and enlarged and projected onto the projection surface.

  The amount of chiral agent of each of the RGB liquid crystal compositions used in the liquid crystal light valve of the projection display device is set as follows, for example.

Green light and red light chiral agent amount: 5wt%
Blue light chiral agent amount: 2wt%

  As a result of image quality evaluation and image quality degradation evaluation using the liquid crystal light valve, it was possible to achieve higher image quality and longer life of the projection display device compared to the case where the amount of chiral agent was the same.

  Note that the above-described effects can be expected when the present invention is applied to any of the liquid crystal light valves of the optical rotation mode, the birefringence mode, such as the simple matrix method, the TFT active matrix method, and the TFD active matrix method.

  Further, the chiral agent used in the liquid crystal layer of the liquid crystal light valve may be other than that shown in FIG. Even when other chiral agents are used, the same effect can be obtained by making the addition amount of the chiral agent of the liquid crystal light valve corresponding to blue light smaller than the addition amount of the chiral agent of the liquid crystal light valve corresponding to green light. be able to.

  Whatever chiral agent is used, the ratio of the chiral agent addition amount of the liquid crystal light valve corresponding to blue light to the chiral agent addition amount of the liquid crystal light valve corresponding to green light is approximately 1: 2. Good.

  Further, an inorganic alignment film can be used instead of polyimide as an organic material for forming the alignment film of the liquid crystal light valve described above. Typical examples include silicon formed by vapor deposition, but it is considered that almost all substances that can be formed by vapor deposition can be used, such as germanium or other group IV element or a mixture or compound.

In addition, a material having a siloxy acid skeleton formed by printing, spin coating, or an ink jet method may be used. In order to form an alignment film on each substrate using these materials, each substrate is introduced into a vapor deposition apparatus, and SiO ₂ is formed by oblique vapor deposition as an alignment film for each substrate. The film thickness is applied to a thickness of about 50 nm. Next, a seal pattern formed except for the inlet is formed. When the image quality evaluation and the image quality degradation evaluation of the liquid crystal composition were performed using the inorganic alignment film, the same result as that of the organic material could be obtained.

According to the present embodiment, the following effects can be obtained.
(1) In a projection type liquid crystal display device such as a projector, it is possible to realize a long life by improving light resistance.
(2) It is possible to realize high contrast by high Δn liquid crystal accompanying a high definition and a narrow cell gap.
(3) Since the material change is only a chiral agent, it is possible to improve reliability, improve workability, and achieve a high yield.
(4) It is possible to obtain a good image quality in a green light liquid crystal light valve in which poor image quality due to insufficient twist, for example, disclination, etc. is particularly noticeable.

It is a schematic cross section explaining the composition of the liquid crystal light valve applied to the liquid crystal module concerning this embodiment. It is a circuit diagram of the active matrix type liquid crystal display element applied to a liquid crystal light valve. It is a schematic cross section of a pixel part. It is a figure which shows an example of a chiral agent. It is a figure which shows an evaluation result. It is a schematic block diagram explaining the structure of a projection type liquid crystal display device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... TFT array substrate, 12 ... Counter substrate, 13 ... Pixel electrode, 14 ... Counter electrode, 16 ... Liquid crystal layer, 22 ... Transistor, 24 ... Source, 25 ... Scan line, 26 ... Drain

Claims (10)

It has three liquid crystal light valves that modulate each color light of red light, green light and blue light,
The liquid crystal light valve is bonded with a sealing material so that a pair of substrates face each other with a predetermined gap, and a liquid crystal layer is sandwiched between the pair of substrates,
The liquid crystal layer of the liquid crystal light valve is composed of a liquid crystal material to which an optical rotatory substance is added,
The content of the optical active substance in the three liquid crystal light valves are Tsu different,
The liquid crystal module is characterized in that the content of the optical rotatory substance in the liquid crystal light valve corresponding to blue light is less than the content of the optical rotatory substance in the liquid crystal light valve corresponding to green light . The liquid crystal module according to claim 1 , wherein a display mode of the liquid crystal layer of the liquid crystal light valve is a twisted nematic mode. 2. The liquid crystal module according to claim 1 , wherein a spacer formed at a predetermined location is used to control a gap between the pair of substrates in the liquid crystal light valve. The liquid crystal module according to claim 1 , wherein the alignment film formed on the pair of substrates in the liquid crystal light valve is an inorganic material. Wherein the refractive index anisotropy of the liquid crystal layer of the liquid crystal light valve is 0.10 or more, the liquid crystal module according to claim 1, gap between the pair of substrates is characterized in that it is 4μm or less. A light source;
A light collecting optical system that separates light emitted from the light source into red light, green light, and blue light having different principal wavelengths and guides them to three liquid crystal light valves;
The liquid crystal light valve is bonded with a sealing material so that a pair of substrates face each other with a predetermined gap, and a liquid crystal layer is sandwiched between the pair of substrates,
The liquid crystal layer of the liquid crystal light valve is composed of a liquid crystal material to which an optical rotatory substance is added,
The content of the optical active substance in the three liquid crystal light valves are Tsu different,
The liquid crystal display device according to claim 1, wherein a content of the optical rotatory material in the liquid crystal light valve corresponding to blue light is less than a content of the optical rotatory material in the liquid crystal light valve corresponding to green light . The liquid crystal display device according to claim 6, wherein a display mode of the liquid crystal layer of the liquid crystal light valve is a twisted nematic mode. The liquid crystal display device according to claim 6, wherein a spacer formed at a predetermined location is used to control a gap between the pair of substrates in the liquid crystal light valve. The liquid crystal display device according to claim 6, wherein the alignment film formed on the pair of substrates in the liquid crystal light valve is an inorganic material. The liquid crystal display device according to claim 6 , wherein a refractive index anisotropy of a liquid crystal layer of the liquid crystal light valve is 0.10 or more, and a gap between the pair of substrates is 4 μm or less.

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