JP2011164330A - Liquid crystal device and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal reflection type liquid crystal device which can obtain beautiful white display, excellent color balance, and bright display at a low cost and further suppress the occurrence of flicker and image persistence. <P>SOLUTION: A liquid crystal device 31 includes a first substrate 1, a second substrate 2, a liquid crystal layer 3, a reflecting electrode 4 disposed on the side facing the second substrate 2, of the first substrate 1, a first insulating film 5 disposed on the reflecting electrode 4, and a first inorganic alignment film 6 disposed on the first insulating film 5. When a refractive index of the liquid crystal layer 3 is represented by nlc and a refractive index of the first insulating film 5 is represented by n1 and a refractive index of the first inorganic alignment film 6 is represented by n2, n1c>n2>n1 is satisfied. When an optical film thickness of the first inorganic alignment film 6 is represented by r2, 50≤r2≤150 is satisfied. When an optical film thickness of the first insulating film 5 is represented by r1, -1.0173×r2+367.29≤r1≤-1.0197×r2+463.34 is satisfied. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid crystal device and a projector.

  2. Description of the Related Art Conventionally, reflective liquid crystal devices that display using external light without using a light source such as a backlight are advantageous from the viewpoint of low power consumption, small size, and light weight. It is used in portable electronic devices. In the field of projectors, a reflective liquid crystal light valve may be employed as a light modulation element from the viewpoint of simplifying the device configuration. In recent years, a reflective liquid crystal of a so-called internal reflection type in which a display electrode (pixel electrode) disposed on a substrate opposite to the light incident side is formed of a reflector and the reflection position is as close as possible to the liquid crystal layer. Devices have been developed to achieve high definition and bright images.

  However, the reflectance of light at the pixel electrode that also serves as a reflector has wavelength dependency, and the reflectance for red light, green light, and blue light contained in external light is different. Therefore, in the case of black and white display, there is a problem that the original white color has a blue color or a green color and cannot display a beautiful white color. In the case of color display, there is a problem that the color balance is lost and the original color cannot be faithfully reproduced, or that special color correction is required and the device configuration and the drive circuit are complicated. Therefore, a liquid crystal device has been proposed that aims to improve spectral reflection characteristics by optimizing the configuration of the substrate on the side where the reflector is disposed (see, for example, Patent Documents 1 and 2 below). On the other hand, a liquid crystal device has been proposed that aims to improve reflection characteristics by optimizing the configuration of the substrate on the side opposite to the side on which the reflector is disposed (see, for example, Patent Document 3 below).

JP 2005-156717 A Japanese Patent No. 3557933 JP-A-11-174427

  Incidentally, in recent years, the use of an alignment film made of an inorganic material has been studied as an alignment film used in a liquid crystal device. For example, when an inorganic alignment film made of a silicon oxide film or the like is formed by oblique deposition, sufficient alignment performance can be exhibited without performing a rubbing process. In addition, since the inorganic alignment film is superior in heat resistance and light resistance as compared with a conventional alignment film using an organic material such as polyimide, it is suitable as a liquid crystal device for projector applications. Therefore, even in a reflective liquid crystal device using an inorganic alignment film, the substrate configuration is optimized to obtain a uniform reflectivity for each color light to achieve beautiful white display and good color balance, as well as bright display There is a demand to do.

  However, none of the above-mentioned Patent Documents 1 to 3 optimizes the substrate configuration on the premise of using an inorganic alignment film, and knows the optimum values of the refractive index and film thickness of various films from Patent Documents 1 to 3. I can't. Moreover, in the structure described in Patent Document 1, two or more dielectric layers having different refractive indexes must be formed on the reflecting plate, and there is a problem that the manufacturing cost increases. Furthermore, in addition to solving the above problems, it is desired to provide a liquid crystal device capable of suppressing the occurrence of flicker and image sticking.

  The present invention has been made to solve the above-described problems, and can achieve beautiful white display, good color balance, bright display at a low cost, and can suppress the occurrence of flicker and image sticking. An object of the present invention is to provide a liquid crystal device. It is another object of the present invention to provide a projector with excellent display quality by using such a liquid crystal device.

In order to achieve the above object, a first liquid crystal device of the present invention includes a first substrate, a light-transmissive second substrate disposed opposite to the first substrate, the first substrate, and the first substrate. A liquid crystal layer sandwiched between two substrates, a reflective electrode disposed on a side of the first substrate facing the second substrate, a first insulating film disposed on the reflective electrode, and the first substrate A first inorganic alignment film disposed on one insulating film, a refractive index of the liquid crystal layer is nlc, a refractive index of the first insulating film is n1, and a refractive index of the first inorganic alignment film is n2. Then, nlc>n2> n1, and if the optical thickness of the first inorganic alignment film is r2, 50 ≦ r2 ≦ 150, and if the optical thickness of the first insulating film is r1,
−1.0173 × r2 + 367.29 ≦ r1 ≦ −1.0197 × r2 + 463.34 (1)
It is characterized by being.

A second liquid crystal device according to the present invention is sandwiched between a first substrate, a second substrate having optical transparency disposed opposite to the first substrate, and the first substrate and the second substrate. A liquid crystal layer; a reflective electrode disposed on a side of the first substrate facing the second substrate; a first insulating film disposed on the reflective electrode; and a first electrode disposed on the first insulating film. Nlc>n1> n2, where nlc is the refractive index of the liquid crystal layer, n1 is the refractive index of the first insulating film, and n2 is the refractive index of the first inorganic alignment film. When the optical film thickness of the first inorganic alignment film is r2, 50 ≦ r2 ≦ 150, and when the optical film thickness of the first insulating film is r1,
−0.7651 × r2 + 325.61 ≦ r1 ≦ −0.7587 × r2 + 429.96 (2)
It is characterized by being.

  Here, in the first and second liquid crystal devices of the present invention, the optical film thickness r1 of the first insulating film is such that when the actual film thickness (physical film thickness) of the first insulating film is d1, r1 = It is represented by n1 × d1. Similarly, the optical film thickness r2 of the first inorganic alignment film is represented by r2 = n2 × d2, where d2 is the actual film thickness (physical film thickness) of the first inorganic alignment film. In the first and second liquid crystal devices of the present invention, the refractive index of the liquid crystal layer, the first insulating film, and the first inorganic alignment film is a plurality of the refractive indexes when the refractive index has anisotropy. It means the average value of the refractive index. The “refractive index” as used in the present invention is defined as the refractive index for light having a wavelength of 550 nm.

  The inventor sets the optical film thickness r2 of the first inorganic alignment film as 50 ≦ r2 ≦ 150 on the premise of the configuration of the first substrate in which the first insulating film and the first inorganic alignment film are sequentially laminated on the reflective electrode. Then, the light reflectance for each wavelength range of light when the optical film thickness of the first insulating film was changed was obtained by simulation. As a result, the optical thickness of the first insulating film is set after appropriately setting the optical film thickness of the first inorganic alignment film in accordance with the magnitude relationship among the refractive indexes of the liquid crystal layer, the first insulating film, and the first inorganic alignment film. If the film thickness is set to a value that satisfies the conditions of the above formula (1) or (2), a relatively high light reflectance can be obtained in any wavelength range, and the light reflectance of each color light can be obtained. We found that the difference was relatively small. Specific simulation results will be described later.

  With the above configuration, a liquid crystal device capable of realizing beautiful white display, good color balance, and bright display can be obtained. Further, according to the configuration of the first and second liquid crystal devices of the present invention, since only one insulating film needs to be formed on the reflective electrode, the above-mentioned Patent Document 1 that requires a plurality of dielectric layers is required. Manufacturing costs can be reduced compared to the configuration. In addition, since the first insulating film becomes a relatively thick insulating film, the effect of reducing flicker and image sticking can be sufficiently obtained.

In the first liquid crystal device of the present invention, the first inorganic alignment film has an anisotropy in refractive index viewed from the normal direction of the substrate, and the larger one of the two refractive indices is n2max. In this case, a configuration satisfying the relationship of nlc>n2max> n1 may be used.
For example, when the first inorganic alignment film is formed by oblique deposition, the refractive index viewed from the normal direction of the substrate may have anisotropy. In this case, as long as the larger refractive index n2max satisfies the relationship nlc>n2max> n1, the average refractive index n2 necessarily satisfies the relationship nlc>n2> n1. Therefore, it is not necessary to grasp a plurality of refractive indexes, and it is only necessary to grasp the larger refractive index, so that the manufacturing conditions and the like can be easily set.

  Similarly, in the second liquid crystal device of the present invention, the first inorganic alignment film has an anisotropy in refractive index viewed from the normal direction of the substrate, and the larger refractive index of the two refractive indexes. When n is 2nmax, a configuration satisfying the relationship of nlc> n1> n2max may be used.

A third liquid crystal device according to the present invention is sandwiched between a first substrate, a second substrate having optical transparency disposed opposite to the first substrate, and the first substrate and the second substrate. A liquid crystal layer, a reflective electrode disposed on a side of the first substrate facing the second substrate, a transparent electrode disposed on a side of the second substrate facing the first substrate, and the transparent electrode And a second inorganic alignment film disposed on the second insulating film, wherein the liquid crystal layer has a refractive index nlc, the transparent electrode has a refractive index nt, 2 If the refractive index of the insulating film is n3, the refractive index of the second inorganic alignment film is n4, nt>nlc>n4> n3, and if the optical film thickness of the transparent electrode is rt, 220 ≦ rt ≦ 276 When the optical film thickness of the second inorganic alignment film is r4, 50 ≦ r4 ≦ 150, and the second absolute alignment film If the optical film thickness of the edge film is r3,
−1.0189 × r4 + 212.05 ≦ r3 ≦ −1.016 × r4 + 325.64 (3)
It is characterized by being.

A fourth liquid crystal device of the present invention is sandwiched between a first substrate, a second substrate having optical transparency disposed opposite to the first substrate, and the first substrate and the second substrate. A liquid crystal layer, a reflective electrode disposed on a side of the first substrate facing the second substrate, a transparent electrode disposed on a side of the second substrate facing the first substrate, and the transparent electrode And a second inorganic alignment film disposed on the second insulating film, wherein the liquid crystal layer has a refractive index nlc, the transparent electrode has a refractive index nt, 2 If the refractive index of the insulating film is n3, the refractive index of the second inorganic alignment film is n4, nt>nlc>n3> n4, and the optical film thickness of the transparent electrode is rt, 220 ≦ rt ≦ 276. When the optical film thickness of the second inorganic alignment film is r4, 50 ≦ r4 ≦ 150, and the second absolute alignment film If the optical film thickness of the edge film is r3,
−0.8401 × r4 + 189.76 ≦ r3 ≦ −0.8323 × r4 + 302.7 (4)
It is characterized by being.

  Here, in the third and fourth liquid crystal devices of the present invention, the optical film thickness rt of the transparent electrode is rt = nt × dt, where dt is the actual film thickness (physical film thickness) of the transparent electrode. Represented. Similarly, the optical film thickness r3 of the second insulating film is represented by r3 = n3 × d3, where d3 is the actual film thickness (physical film thickness) of the second insulating film. Similarly, the optical film thickness r4 of the second inorganic alignment film is represented by r4 = n4 × d4, where d4 is the actual film thickness (physical film thickness) of the second inorganic alignment film. In the first and second liquid crystal devices of the present invention, the refractive index of the liquid crystal layer, the second insulating film, and the second inorganic alignment film is a plurality of the refractive indexes when the refractive index has anisotropy. It means the average value of the refractive index. The “refractive index” as used in the present invention is defined as the refractive index for light having a wavelength of 550 nm.

The present inventor optimizes not only the above-mentioned configuration on the first substrate side but also the light transmittance on the second substrate side having light transmittance, so that the entire liquid crystal device is uniform and high regardless of the wavelength range. I wanted to get light reflectivity.
Therefore, on the premise of a configuration including a first substrate on which a reflective electrode is formed and a second substrate in which a second insulating film and a second inorganic alignment film are sequentially stacked on the transparent electrode, the optical film thickness rt of the transparent electrode is assumed. Is set to 220 ≦ rt ≦ 276, the optical film thickness r4 of the second inorganic alignment film is set to 50 ≦ r4 ≦ 150, and the optical film thickness of the second insulating film is changed for each wavelength region of light. The light transmittance was determined by simulation. As a result, after setting the optical film thickness of the second inorganic alignment film to a predetermined value in accordance with the magnitude relationship of the refractive indexes of the liquid crystal layer, the transparent electrode, the second insulating film, and the second inorganic alignment film described above. If the optical film thickness of the second insulating film is set to a value satisfying the condition of the above formula (3) or (4), a relatively high light transmittance can be obtained in any wavelength range, and each color It has been found that the difference in light transmittance is relatively small. Specific simulation results will be described later.

  With the above configuration, a liquid crystal device capable of realizing beautiful white display, good color balance, and bright display can be obtained. Further, according to the configurations of the third and fourth liquid crystal devices of the present invention, since only one insulating film needs to be formed on the transparent electrode, the above-mentioned Patent Document 1 that requires a plurality of dielectric layers is required. Manufacturing costs can be reduced compared to the configuration. In addition, since the second insulating film becomes a relatively thick insulating film, the effect of reducing flicker and image sticking can be sufficiently obtained.

In the third liquid crystal device of the present invention, the second inorganic alignment film has an anisotropy in refractive index viewed from the normal direction of the substrate, and the larger refractive index of the two refractive indexes is n4max. In this case, a configuration satisfying the relationship of nt>nlc>n4max> n3 may be used.
For example, when the second inorganic alignment film is formed by oblique deposition, the refractive index viewed from the normal direction of the substrate may have anisotropy. In that case, as long as the larger refractive index n4max satisfies the relationship of nt>nlc>n4max> n3, the average refractive index n4 necessarily satisfies the relationship of nt>nlc>n4> n3. Therefore, it is not necessary to grasp a plurality of refractive indexes, and it is only necessary to grasp the larger refractive index, so that the manufacturing conditions and the like can be easily set.

  Similarly, in the fourth liquid crystal device of the present invention, the second inorganic alignment film has an anisotropy in refractive index viewed from the normal direction of the substrate, and the larger refractive index of the two refractive indexes. It may be a configuration satisfying the relationship of nt> nlc> n3> n4max, where n4max is set.

In the first to fourth liquid crystal devices of the present invention, the first insulating film or the second insulating film is a silicon oxide film formed by a CVD method or a vapor deposition method, and the first inorganic alignment film or the first insulating film is formed. 2 The inorganic alignment film may be a silicon oxide film formed by oblique vapor deposition.
According to this configuration, the configuration of the present invention can be easily realized by using a general material and a general method, which can contribute to cost reduction.

The projector of the present invention includes a light source, a light modulation element that modulates light from the light source, and a projection optical system that projects an image formed by the light modulation element, and the light modulation element is the present invention. It is characterized by comprising the above liquid crystal device.
According to this configuration, since the light modulation element includes the liquid crystal device of the present invention having a uniform and high light reflectance, a projector having excellent display quality can be realized.

It is sectional drawing which shows the liquid crystal device of 1st Embodiment of this invention. It is a figure explaining the refractive index anisotropy of the 1st inorganic alignment film of a liquid crystal device similarly. It is the graph which compared the wavelength dependence of the light reflectivity by the presence or absence of the 1st insulating film. It is a graph which shows the 1st insulating film thickness dependence of the light reflectivity in predetermined | prescribed 1st inorganic alignment film thickness. It is a graph which shows the 1st insulating film thickness dependence of the light reflectivity in the 1st inorganic orientation film thickness different from FIG. It is a graph which shows the 1st insulating film thickness dependence of the light reflectivity in the 1st inorganic orientation film thickness different from FIG. It is a graph which shows the relationship between the 1st inorganic orientation film thickness and the 1st insulating film thickness from which an optimal light reflectance is obtained. It is sectional drawing which shows the liquid crystal device of 2nd Embodiment of this invention. It is a figure explaining the refractive index anisotropy of the 1st inorganic alignment film of a liquid crystal device similarly. It is the graph which compared the wavelength dependence of the light reflectivity by the presence or absence of the 1st insulating film. It is a graph which shows the 1st insulating film thickness dependence of the light reflectivity in predetermined | prescribed 1st inorganic alignment film thickness. It is a graph which shows the 1st insulating film thickness dependence of the light reflectivity in the 1st inorganic orientation film thickness different from FIG. It is a graph which shows the 1st insulating film thickness dependence of the light reflectivity in the 1st inorganic orientation film thickness different from FIG. It is a graph which shows the relationship between the 1st inorganic orientation film thickness and the 1st insulating film thickness from which an optimal light reflectance is obtained. It is sectional drawing which shows the liquid crystal device of 3rd Embodiment of this invention. It is the graph which compared the wavelength dependence of the light transmittance with the presence or absence of the 2nd insulating film. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in predetermined | prescribed 2nd inorganic orientation film thickness. It is a graph which shows the 2nd insulating film thickness dependence of the light transmittance in the 2nd inorganic orientation film thickness different from FIG. It is a graph which shows the 2nd insulating film thickness dependence of the light transmittance in the 2nd inorganic orientation film thickness different from FIG. It is a graph which shows the relationship between the 2nd inorganic alignment film thickness and 2nd insulating film thickness in which optimal light transmittance is obtained. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in a predetermined 2nd inorganic orientation film thickness and a predetermined transparent electrode film thickness. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in the transparent electrode film thickness different from FIG. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in the transparent electrode film thickness different from FIG. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in the transparent electrode film thickness different from FIG. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in the transparent electrode film thickness different from FIG. It is a graph which shows the 2nd insulating film thickness dependence of the light transmittance in the 2nd inorganic orientation film thickness different from FIGS. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in the transparent electrode film thickness different from FIG. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in the transparent electrode film thickness different from FIG. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in the transparent electrode film thickness different from FIG. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in the transparent electrode film thickness different from FIG. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in the transparent electrode film thickness different from FIG. It is a graph which shows the 2nd insulating film thickness dependence of the light transmittance in the 2nd inorganic orientation film thickness different from FIGS. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in the transparent electrode film thickness different from FIG. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in the transparent electrode film thickness different from FIG. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in the transparent electrode film thickness different from FIG. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in the transparent electrode film thickness different from FIG. It is sectional drawing which shows the liquid crystal device of 4th Embodiment of this invention. It is the graph which compared the wavelength dependence of the light transmittance with the presence or absence of the 2nd insulating film. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in predetermined | prescribed 2nd inorganic orientation film thickness. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in the 2nd inorganic orientation film thickness different from FIG. It is a graph which shows the 2nd insulation film thickness dependence of the light transmittance in the 2nd inorganic orientation film thickness different from FIG. It is a graph which shows the relationship between the 2nd inorganic alignment film thickness and 2nd insulating film thickness in which optimal light transmittance is obtained. It is a schematic block diagram which shows one Embodiment of the projector of this invention.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
The liquid crystal device of the present embodiment is an example of a reflective liquid crystal device that performs display by reflecting light incident from the second substrate side on the first substrate side and then emitting it again from the second substrate side.
Further, the following first and second embodiments are examples in which the configuration of the first substrate on the side where the reflective electrodes are arranged is optimized.
FIG. 1 is a cross-sectional view showing the liquid crystal device of this embodiment. FIG. 2 is a diagram for explaining the refractive index anisotropy of the first inorganic alignment film. FIG. 3 is a graph comparing the wavelength dependence of the light reflectance with and without the first insulating film. 4 to 6 are graphs showing the first insulating film thickness dependence of the light reflectance at three different first inorganic alignment film thicknesses. FIG. 7 is a graph showing the relationship between the first inorganic alignment film thickness and the first insulating film thickness that provide the optimum light reflectance.
In the following drawings, in order to make each component easy to see, the dimensions and scale may be changed depending on the component.

  As shown in FIG. 1, the liquid crystal device 31 according to the present embodiment includes a first substrate 1 that constitutes an element substrate and a second substrate having optical transparency that constitutes a counter substrate disposed opposite to the first substrate 1. 2 and a liquid crystal layer 3 sandwiched between a first substrate 1 and a second substrate 2. The first substrate 1 may or may not have light transparency. For example, a glass substrate having light transparency or a silicon substrate having no light transparency may be used. . As the second substrate 2, a light transmissive glass substrate, a quartz substrate, or the like is used. In the present embodiment, a TFT substrate employing a thin film transistor (hereinafter abbreviated as TFT) as a pixel switching element is used as an element substrate constituting the first substrate 1, but in FIG. (Line), gate line (scanning line), TFT, etc. are not shown.

  A reflective electrode 4 is formed on the surface of the first substrate 1 facing the second substrate 2. As the material of the reflective electrode 4, it is preferable to use a metal such as aluminum having a high light reflectance. On the reflective electrode 4, the 1st insulating film 5 and the 1st inorganic alignment film 6 are laminated | stacked in this order from the board | substrate side.

In the present embodiment, a silicon oxide film (SiO ₂ ) formed by a plasma CVD method is used as the first insulating film 5. Note that not only the plasma CVD method but also a method formed by an atmospheric pressure CVD method, a low pressure CVD method, or the like may be used. The actual film thickness (physical film thickness) d1 of the first insulating film 5 is preferably 150 nm ≦ d1 ≦ 280 nm, for example, 225 nm. The refractive index n1 of the first insulating film 5 is 1.460.

As the first inorganic alignment film 6, a silicon oxide film (SiO ₂ ) formed by oblique deposition is used. The conditions for oblique vapor deposition are that the degree of vacuum is 5 × 10 ⁻³ Pa, and vapor deposition is performed from a direction inclined by 50 degrees from the substrate normal direction to the X-axis direction (see FIG. 1). When an inorganic alignment film is formed by oblique deposition, an elliptical refractive index anisotropy occurs when viewed from the substrate normal direction (viewed from an infinite position in the Z-axis direction) as shown in FIG. . The refractive index in the X-axis direction (refractive index felt by polarized light vibrating in the X-axis direction) nx is 1.463 (= n2max), and the refractive index in the Y-axis direction (refractive index felt by polarized light vibrating in the Y-axis direction) ny is 1.461 (= n2 min). Therefore, the average refractive index n2 of the first inorganic alignment film 6 is 1.462. The actual film thickness (physical film thickness) d2 of the first inorganic alignment film 6 is preferably 30 nm ≦ d2 ≦ 100 nm, for example, 60 nm.

  The refractive index nlc of the liquid crystal layer 3 is determined by nlc = (ne + 2 × no) / 3 (ne: extraordinary light refractive index, no: ordinary light refractive index), and is 1.52. Therefore, in the present embodiment, the magnitude relationship among the refractive index nlc of the liquid crystal layer 3, the refractive index n1 of the first insulating film 5, and the refractive index n2 of the first inorganic alignment film 6 is nlc> n2> n1. Further, when the optical film thickness of the first inorganic alignment film 6 is r2, r2 = n2 × d2, and therefore r2 is approximately 44 ≦ r2 ≦ 146. In the present embodiment, the refractive index of the first inorganic alignment film 6 has anisotropy. However, since the average refractive index n2 only needs to satisfy the above magnitude relationship, The smaller refractive index n2min (ny) may be smaller than the refractive index n1 of the first insulating film 5.

  On the other hand, a transparent electrode 7 is formed on the surface of the second substrate 2 facing the first substrate 1. A second inorganic alignment film 8 is formed on the transparent electrode 7. In the present embodiment, ITO is used as the material of the transparent electrode 7. The second inorganic alignment film 8 is a silicon oxide film formed by oblique vapor deposition as in the case of the first inorganic alignment film 6 on the first substrate 1 side. The oblique deposition conditions are preferably the same as those of the first inorganic alignment film 6, but may be different.

  Here, the present inventor performed a simulation for comparing the wavelength dependence of the light reflectance with and without the first insulating film 5. The result is shown in FIG. In FIG. 3, the horizontal axis represents the light wavelength [nm], and the vertical axis represents the light reflectance [%] in the liquid crystal medium. The dashed curve indicates the case without the first insulating film 5, and the solid curve indicates the case with the first insulating film 5 (actual film thickness d1 = 225 nm).

  As long as the wavelength is 550 nm (green light), the light reflectance is almost the same regardless of whether or not the first insulating film 5 is present. However, looking at the region of wavelength 460 nm (blue light) and the region of wavelength 620 nm (red light), when the first insulating film 5 is present, the wavelength at 460 nm is greater than when the first insulating film 5 is absent. The light reflectance and the light reflectance at a wavelength of 620 nm are close to each other. That is, flat spectral characteristics are obtained when the first insulating film 5 is provided, compared to when the first insulating film 5 is not provided. From this, it was found that the first insulating film 5 is more advantageous than the absence of the first insulating film 5 from the viewpoint of obtaining a uniform light reflectance over a wide wavelength range corresponding to the visible light region. .

  Next, a simulation was performed in which the film thickness of the first inorganic alignment film 6 was changed and the dependence of the light reflectance at each film thickness on the first insulating film thickness was compared. The results are shown in FIGS. 4 to 6, the horizontal axis represents the physical thickness [nm] of the first insulating film, and the vertical axis represents the light reflectance [%] in the liquid crystal medium. The solid curve is the light reflectance for light with a wavelength of 460 nm (blue light), the dashed curve is the light reflectance for light with a wavelength of 550 nm (green light), and the two-dot chain curve is the light for light with a wavelength of 620 nm (red light). Reflectivity. 4 shows a physical film thickness of the first inorganic alignment film 6 of 30 nm, FIG. 5 shows a physical film thickness of the first inorganic alignment film 6 of 65 nm, and FIG. 6 shows a physical film thickness of the first inorganic alignment film 6 of 100 nm. This is the case.

  As apparent from FIGS. 4 to 6, in each case, the light reflectance has a maximum value and a minimum value centered on the average value as the physical film thickness of the first inorganic alignment film 6 changes. It changes smoothly while taking. Overall, the light reflectance for light with a wavelength of 460 nm (blue light) is at the highest level, and the light reflectance decreases in the order of light with a wavelength of 550 nm (green light) and light with a wavelength of 620 nm (red light).

  In the present embodiment, the optimum range of the film thickness of the first insulating film 5 is an area where the light reflectance of light (red light) having a wavelength 620 nm having the lowest light reflectance is equal to or greater than the average value (86%). In addition, the light reflectance of light with a wavelength of 550 nm (green light) having the highest visual sensitivity of the human eye is in an area where the average value (87.6%) or more and light with a wavelength of 460 nm (blue light) ) Is defined as a region that is closest to the light reflectance of light having a wavelength of 620 nm (red light) and light having a wavelength of 550 nm (green light).

  Judging from this viewpoint, when the film thickness d2 of the first inorganic alignment film 6 shown in FIG. 4 is 30 nm, the optimum film thickness d1 of the first insulating film 5 is 220 nm ≦ d1 ≦ 280 nm, which is shown in FIG. When the thickness d2 of the inorganic alignment film 6 is 65 nm, the optimum range d1 of the thickness of the first insulating film 5 is 180 nm ≦ d1 ≦ 250 nm, and the thickness d2 of the first inorganic alignment film 6 shown in FIG. The optimum range d1 of the film thickness of the first insulating film 5 is 150 nm ≦ d1 ≦ 220 nm. Thus, as the film thickness d2 of the first inorganic alignment film 6 increases, the optimum range of the film thickness d1 of the first insulating film 5 shifts to the smaller side.

  FIG. 7 shows an optimum combination of the film thickness d2 of the first inorganic alignment film 6 and the film thickness d1 of the first insulating film 5. In FIG. 7, the horizontal axis represents the optical film thickness [nm] of the first inorganic alignment film 6, and the vertical axis represents the optical film thickness [nm] of the first insulating film 5. Here, the optical film thickness which is the product of the refractive index of each film and the physical film thickness is used for both the horizontal axis and the vertical axis. That is, the optical film thickness r1 of the first insulating film 5 is represented by r1 = n1 × d1, and the optical film thickness r2 of the first inorganic alignment film 6 is represented by r2 = n2 × d2.

When the optimal range of FIGS. 4 to 6 is written on FIG. 7, the optimal range is set when the optical film thickness r2 of the first inorganic alignment film 6 is set to a range of 50 ≦ r2 ≦ 150, which is a range that is normally used. This is a hatched area sandwiched between two straight lines, a two-dot chain line and a solid line. When the hatched region is expressed by a mathematical expression, the optimum range of the optical film thickness r1 of the first insulating film 5 is
−1.0173 × r2 + 367.29 ≦ r1 ≦ −1.0197 × r2 + 463.34 (1)
It becomes.

  According to the liquid crystal device 31 of the present embodiment, as described above, the optical film thickness r1 of the first insulating film 5 and the optical film thickness r2 of the first inorganic alignment film 6 positioned on the reflective electrode 4 are optimized. Therefore, a relatively high light reflectance is obtained in any wavelength region of the visible light region, and the light reflectance in each wavelength region is relatively uniform. Thereby, a liquid crystal device capable of realizing beautiful white display, good color balance, and bright display can be realized. Further, since only one insulating film needs to be formed on the reflective electrode 4, the cost can be reduced. Moreover, since the physical film thickness of the first insulating film 5 is about 150 nm to 280 nm and becomes a relatively thick insulating film, flicker and image sticking can be sufficiently reduced.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the liquid crystal device of this embodiment is the same as that of the first embodiment, and only the configurations of the first insulating film and the first inorganic alignment film are different from those of the first embodiment.
Therefore, in FIG. 8, the same reference numerals are given to the same components as those in FIG. 1, and detailed description will be omitted.

In the liquid crystal device 32 of the present embodiment, unlike the first embodiment, as the first insulating film 15, for example, a silicon film having a film thickness of 15 nm formed by vapor deposition on a silicon oxide film (SiO ₂ ) formed by plasma CVD method having a film thickness of 200 nm. A stacked layer of oxide films (SiO ₂ ) is used. Note that the silicon oxide film formed by the plasma CVD method on the lower layer side is not necessarily limited to the plasma CVD method but may be formed by an atmospheric pressure CVD method, a low pressure CVD method, or the like. Therefore, the actual film thickness (physical film thickness) d1 of the first insulating film 15 is 215 nm as a whole. The actual film thickness (physical film thickness) d1 of the first insulating film 15 is preferably 150 nm ≦ d1 ≦ 270 nm. The refractive index (average refractive index) n1 of the first insulating film 15 is 1.46.

As the first inorganic alignment film 16, a silicon oxide film (SiO ₂ ) formed by oblique deposition is used. The oblique vapor deposition conditions are different from the first embodiment, and the degree of vacuum is 5 × 10 ⁻³ Pa, and the vapor deposition is performed from a direction inclined 45 degrees from the substrate normal direction to the X-axis direction (see FIG. 8). When an inorganic alignment film is formed by oblique deposition, an elliptical refractive index anisotropy occurs when viewed from the substrate normal direction (viewed from an infinite position in the Z-axis direction) as shown in FIG. . The refractive index in the X-axis direction (refractive index felt by polarized light vibrating in the X-axis direction) nx is 1.40 (= n2 min), and the refractive index in the Y-axis direction (refractive index felt by polarized light vibrating in the Y-axis direction) ny is It is assumed that 1.42 (= n2max). Therefore, the average refractive index n2 of the first inorganic alignment film 16 is 1.41. The actual film thickness (physical film thickness) d2 of the first inorganic alignment film 16 is preferably 30 nm ≦ d2 ≦ 100 nm, for example, 60 nm.

  The refractive index nlc of the liquid crystal layer 3 is obtained by nlc = (ne + 2 × no) / 3 (ne: extraordinary light refractive index, no: ordinary light refractive index), and nlc is 1.52. Therefore, in this embodiment, the magnitude relationship among the refractive index nlc of the liquid crystal layer 3, the refractive index n1 of the first insulating film 15, and the refractive index n2 of the first inorganic alignment film 16 is nlc> n1> n2. Also, assuming that the optical film thickness of the first inorganic alignment film 16 is r2, r2 = n2 × d2, so that r2 is approximately 42 ≦ r2 ≦ 141. In the present embodiment, since the average refractive index n2 of the first inorganic alignment film 16 only needs to satisfy the above magnitude relationship, the larger refractive index n2max (ny) of the first inorganic alignment film 16 is the first insulation. The refractive index n1 of the film 15 may be larger.

  Similar to the first embodiment, the present inventor performed a simulation for comparing the wavelength dependence of the light reflectance with and without the first insulating film 15. The result is shown in FIG. In FIG. 10, the horizontal axis represents the light wavelength [nm], and the vertical axis represents the light reflectance [%] in the liquid crystal medium. A broken line curve indicates the case where the first insulating film 15 is not provided, and a solid line curve indicates the case where the first insulating film 15 is provided (actual film thickness d1 = 215 nm).

  In the region of a wavelength of 550 nm (green light), the light reflectance hardly changes even if the first insulating film 15 is present or absent. However, looking at the region of wavelength 460 nm (blue light) and the region of wavelength 620 nm (red light), the case where the first insulating film 15 is present is the wavelength at 460 nm compared to the case where the first insulating film 15 is not present. The light reflectance and the light reflectance at a wavelength of 620 nm are close to each other. That is, flat spectral characteristics are obtained when the first insulating film 15 is provided compared to when the first insulating film 15 is not provided. From this, it was found that the presence of the first insulating film 15 is more advantageous than the absence of the first insulating film 15. Further, in the present embodiment, the light reflectance value at each wavelength is further closer than in the first embodiment, and flatter spectral characteristics are obtained. Therefore, it has been found that the effect of the present invention is increased when the refractive index n2 of the first inorganic alignment film 16 is smaller.

  Next, a simulation was performed in which the film thickness of the first inorganic alignment film 16 was changed and the dependence of the light reflectance at each film thickness on the first insulating film thickness was compared. The results are shown in FIGS. 11 to 13, the horizontal axis represents the physical thickness [nm] of the first insulating film 15, and the vertical axis represents the light reflectance [%] in the liquid crystal medium. The solid curve is the light reflectance for light with a wavelength of 460 nm (blue light), the dashed curve is the light reflectance for light with a wavelength of 550 nm (green light), and the two-dot chain curve is the light for light with a wavelength of 620 nm (red light). The reflectance is shown respectively. 11 shows the case where the thickness of the first inorganic alignment film 16 is 30 nm, FIG. 12 shows the case where the thickness of the first inorganic alignment film 16 is 65 nm, and FIG. 13 shows the case where the thickness of the first inorganic alignment film 16 is 100 nm.

  As apparent from FIGS. 11 to 13, the dependency of the light reflectance on the first insulating film thickness shows the same behavior as in the first embodiment, but the variation of the light reflectance with respect to the increase and decrease of the first insulating film thickness is the first. It is larger than one embodiment. If the optimum range of the film thickness of the first insulating film 15 is determined in the same manner as in the first embodiment, when the film thickness d2 of the first inorganic alignment film 16 shown in FIG. When the film thickness d2 of the first inorganic alignment film 16 shown in FIG. 12 is 65 nm, the film thickness d2 of the first insulating film 15 is 170 nm ≦ d1 ≦ 250 nm. When the film thickness d2 of the first inorganic alignment film 16 shown in FIG. 13 is 100 nm, the optimum film thickness d1 of the first insulating film 15 is 150 nm ≦ d1 ≦ 220 nm.

  FIG. 14 shows an optimal combination of the first inorganic alignment film thickness d2 and the first insulating film thickness d1. In FIG. 14, the horizontal axis represents the optical film thickness [nm] of the first inorganic alignment film, and the vertical axis represents the optical film thickness [nm] of the first insulating film. Here, the optical film thickness which is the product of the refractive index of each film and the physical film thickness is used for both the horizontal axis and the vertical axis. That is, the optical film thickness r1 of the first insulating film is represented by r1 = n1 × d1, and the optical film thickness r2 of the first inorganic alignment film is represented by r2 = n2 × d2.

When the optimum range of FIGS. 11 to 13 is written on FIG. 14, the optimum range is set when the optical film thickness r2 of the first inorganic alignment film 16 is set to a range of 50 ≦ r2 ≦ 150, which is a range that is normally used. This is a hatched area sandwiched between two straight lines indicated by a two-dot chain line and a solid line. When the hatched region is expressed by a mathematical expression, the optimum range of the optical film thickness r1 of the first insulating film 15 is
−0.7651 × r2 + 325.61 ≦ r1 ≦ −0.7587 × r2 + 429.96 (2)
It becomes.

  According to the liquid crystal device 32 of the present embodiment, as in the first embodiment, the optical film thickness r1 of the first insulating film 15 and the optical film thickness r2 of the first inorganic alignment film 16 are optimized. High light reflectivity can be obtained even in the wavelength range, and the light reflectivity in each wavelength range becomes uniform. As a result, a liquid crystal device capable of realizing beautiful white display, good color balance, and bright display can be obtained. Further, since only one insulating film needs to be formed on the reflective electrode 4, the cost can be reduced. Further, since the physical thickness of the first insulating film 15 is about 150 nm to 270 nm and becomes a relatively thick insulating film, flicker and image sticking can be sufficiently reduced.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIGS.
The following third and fourth embodiments are examples in which the configuration of the second substrate on the side opposite to the side where the reflective electrode is arranged is optimized.
FIG. 15 is a cross-sectional view showing the liquid crystal device of this embodiment. FIG. 16 is a graph comparing the wavelength dependency of the light transmittance with and without the second insulating film. 17 to 19 are graphs showing the second insulating film thickness dependence of the light transmittance in three different second inorganic alignment film thicknesses. FIG. 20 is a graph showing the relationship between the second inorganic alignment film thickness and the second insulating film thickness that provide the optimum light reflectance. FIG. 21 to FIG. 36 are graphs showing the second insulating film thickness dependence of the light reflectance when both the transparent electrode film thickness and the second inorganic alignment film thickness are varied.
The basic configuration of the liquid crystal device of this embodiment is the same as that of the first embodiment, and the configuration on the second substrate side is only different from that of the first embodiment.
Therefore, in FIG. 15, the same reference numerals are given to the same components as those in FIG. 1, and detailed description will be omitted.

  As shown in FIG. 15, the liquid crystal device 33 of the present embodiment has the transparent electrode 17 formed on the surface of the second substrate 2 facing the first substrate 1. As the material of the transparent electrode 17, it is preferable to use a transparent conductive film such as ITO having a high light transmittance. In the case of this embodiment, specifically, ITO having a film thickness of 140 nm formed by sputtering is used. The actual film thickness (physical film thickness) dt of the transparent electrode 17 is desirably 120 nm ≦ dt ≦ 150 nm. The refractive index nt of the transparent electrode 17 is 1.84. On the transparent electrode 17, the 2nd insulating film 18 and the 2nd inorganic alignment film 19 are laminated | stacked in this order from the board | substrate side. The configuration on the first substrate 1 side can be the same as that of the first embodiment or the second embodiment.

In the present embodiment, as the second insulating film 18, this silicon oxide film having a thickness of 100nm by plasma CVD silicon oxide film (SiO ₂₎ and the film thickness 10nm by conventional vapor deposition (SiO ₂₎ from the substrate side Those stacked in order are used. Therefore, the actual film thickness (physical film thickness) d3 of the second insulating film 18 is 110 nm in total. The actual film thickness (physical film thickness) d3 of the second insulating film 18 is preferably 40 nm ≦ d3 ≦ 190 nm. The refractive index n3 of the second insulating film 18 is 1.460.

As the second inorganic alignment film 19, a silicon oxide film (SiO ₂ ) formed by oblique vapor deposition is used. The oblique deposition conditions are such that the degree of vacuum is 5 × 10 ⁻³ Pa and the deposition is performed from a direction inclined by 50 degrees from the normal direction of the substrate to the X-axis direction (see FIG. 15). The refractive index in the X-axis direction of the second inorganic alignment film 19 (the refractive index felt by polarized light vibrating in the X-axis direction) nx is 1.463 (= n4max), and the refractive index in the Y-axis direction (polarized light vibrating in the Y-axis direction). Is assumed to be 1.461 (= n4 min). Therefore, the average refractive index n4 of the second inorganic alignment film 19 is 1.462. The actual film thickness (physical film thickness) d4 of the second inorganic alignment film 19 is preferably 30 nm ≦ d2 ≦ 100 nm, for example, 60 nm.

  The refractive index nlc of the liquid crystal layer 3 is 1.52 as in the first and second embodiments. Therefore, in the case of the present embodiment, the magnitude relationship among the refractive index nt of the transparent electrode 17, the refractive index nlc of the liquid crystal layer 3, the refractive index n3 of the second insulating film 18, and the refractive index n4 of the second inorganic alignment film 19 is nt. > Nlc> n4> n3. Also, assuming that the optical film thickness of the second inorganic alignment film 19 is r4, r4 = n4 × d4, and therefore r4 is approximately 44 ≦ r2 ≦ 146. In the case of the present embodiment, the refractive index of the second inorganic alignment film 19 has anisotropy, but the average refractive index n4 only needs to satisfy the above magnitude relationship. The smaller refractive index n4min (ny) may be smaller than the refractive index n3 of the second insulating film 18.

  Here, the present inventor performed a simulation for comparing the wavelength dependence of the light transmittance with and without the second insulating film 18. The result is shown in FIG. In FIG. 16, the horizontal axis represents the light wavelength [nm], and the vertical axis represents the light transmittance [%] from the second substrate 2 to the liquid crystal layer 3. The broken curve indicates the case where the second insulating film 18 is not provided, and the solid curve indicates the case where the second insulating film 18 is provided (actual film thickness d3 = 110 nm).

  In the region of wavelength 550 nm (green light), the light transmittance is improved when the second insulating film 18 is present, compared to the case where the second insulating film 18 is not present. Further, also in the region of wavelength 460 nm (blue light) and the region of wavelength 620 nm (red light), the light transmittance is improved when the second insulating film 18 is provided compared to the case where the second insulating film 18 is not provided. The value is close to the light transmittance at a wavelength of 550 nm. That is, flat spectral characteristics are obtained when the second insulating film 18 is provided, compared to when the second insulating film 18 is not provided. From this, it was found that the presence of the second insulating film 18 is more advantageous than the absence of the second insulating film 18 from the viewpoint of obtaining uniform light transmittance over a wide wavelength range.

  Next, a simulation was performed in which the film thickness of the second inorganic alignment film 19 was changed and the dependence of the light transmittance at each film thickness on the second insulating film thickness was compared. The results are shown in FIGS. 17 to 19, the horizontal axis represents the physical thickness [nm] of the second insulating film 18, and the vertical axis represents the light transmittance [%] from the second substrate 2 to the liquid crystal layer 3. The solid curve is the light transmittance for light with a wavelength of 460 nm (blue light), the dashed curve is the light transmittance for light with a wavelength of 550 nm (green light), and the two-dot chain curve is the light for light with a wavelength of 620 nm (red light). Transmittance. 17 shows the case where the thickness of the second inorganic alignment film 19 is 30 nm, FIG. 18 shows the case where the thickness of the second inorganic alignment film 19 is 65 nm, and FIG. 19 shows the case where the thickness of the second inorganic alignment film 19 is 100 nm.

  As is apparent from FIGS. 17 to 19, in each case, the light transmittance takes a maximum value and a minimum value centering on the average value as the film thickness of the second inorganic alignment film 19 increases and decreases. It changes smoothly. Overall, the light transmittance with respect to light with a wavelength of 550 nm (green light) is at the highest level, and the light transmittance decreases in the order of light with a wavelength of 620 nm (red light) and light with a wavelength of 460 nm (blue light).

  In the present embodiment, the optimal range of the film thickness of the second insulating film 18 is a region in which the light transmittance of light (blue light) having the lowest light transmittance of 460 nm is an average value (98%) or more, It is defined as In this region, even if the film thickness of the second inorganic alignment film 19 is changed (in any case of FIGS. 17 to 19), the light transmittance in 620 nm light (red light) is not less than the average value, In addition, the light transmittance of light with a wavelength of 550 nm (green light) tends to decrease and approaches the light transmittance of light with a wavelength of 620 nm (red light) and light with a wavelength of 460 nm (blue light).

  Judging from this viewpoint, when the thickness d4 of the second inorganic alignment film 19 shown in FIG. 17 is 30 nm, the optimum range d3 of the thickness of the second insulating film 18 is 110 nm ≦ d3 ≦ 190 nm, and the second thickness shown in FIG. When the film thickness d4 of the inorganic alignment film 19 is 65 nm, the optimum film thickness d3 of the second insulating film 18 is 80 nm ≦ d3 ≦ 160 nm, and when the film thickness d4 of the second inorganic alignment film 19 shown in FIG. The optimum range d3 of the film thickness of the second insulating film 18 is 40 nm ≦ d3 ≦ 120 nm. Thus, as the film thickness d4 of the second inorganic alignment film 19 increases, the optimum range of the film thickness d3 of the second insulating film 18 shifts to the smaller side.

  FIG. 20 shows an optimal combination of the film thickness d4 of the second inorganic alignment film 19 and the film thickness d3 of the second insulating film 18. In FIG. 20, the horizontal axis represents the optical film thickness [nm] of the second inorganic alignment film 19, and the vertical axis represents the optical film thickness [nm] of the second insulating film 18. Here, the optical film thickness which is the product of the refractive index of each film and the physical film thickness is used for both the horizontal axis and the vertical axis. That is, the optical film thickness r3 of the second insulating film 18 is represented by r3 = n3 × d3, and the optical film thickness r4 of the second inorganic alignment film 19 is represented by r4 = n4 × d4.

When the optimum range of FIGS. 17 to 19 is written on FIG. 20, the optimum range is set when the optical film thickness r4 of the second inorganic alignment film 19 is set to a range of 50 ≦ r4 ≦ 150, which is a normally used range. This is a hatched area sandwiched between two straight lines, a two-dot chain line and a solid line. When the hatched region is expressed by a mathematical expression, the optimum range of the optical film thickness r3 of the second insulating film 18 is
−1.0189 × r4 + 212.05 ≦ r3 ≦ −1.016 × r4 + 325.64 (3)
It becomes.

  Next, after changing the film thickness of the transparent electrode 17, the film thickness of the 2nd inorganic alignment film 19 was changed, and the simulation which compares the 2nd insulation film thickness dependence of the light transmittance in each film thickness was performed. The results are shown in FIGS. In FIGS. 21 to 36, the horizontal axis represents the physical film thickness [nm] of the second insulating film 18, and the vertical axis represents the light transmittance [%] from the second substrate 2 to the liquid crystal layer 3. The solid curve is the light transmittance for light with a wavelength of 460 nm (blue light), the dashed curve is the light transmittance for light with a wavelength of 550 nm (green light), and the two-dot chain curve is the light for light with a wavelength of 620 nm (red light). Transmittance.

  21 to 25 show the case where the film thickness d4 of the second inorganic alignment film 19 is 30 nm, FIG. 21 shows the film thickness of the transparent electrode 17 is 120 nm, FIG. 22 shows the film thickness of the transparent electrode 17 is 130 nm, and FIG. FIG. 24 shows the case where the film thickness of the transparent electrode 17 is 140 nm, FIG. 24 shows the film thickness of the transparent electrode 17 is 150 nm, and FIG. 25 shows the film thickness of the transparent electrode 17 is 160 nm. 26 to 31 show the case where the film thickness d4 of the second inorganic alignment film 19 is 65 nm, FIG. 26 shows the film thickness of the transparent electrode 17 is 70 nm, FIG. 27 shows the film thickness of the transparent electrode 17 is 120 nm, 28 shows the film thickness of the transparent electrode 17 is 130 nm, FIG. 29 shows the film thickness of the transparent electrode 17 is 140 nm, FIG. 30 shows the film thickness of the transparent electrode 17 is 150 nm, and FIG. 31 shows the film thickness of the transparent electrode 17 is 160 nm. Is the case. 32 to 36 show the case where the film thickness d4 of the second inorganic alignment film 19 is 100 nm, FIG. 32 shows the film thickness of the transparent electrode 17 is 120 nm, FIG. 33 shows the film thickness of the transparent electrode 17 is 130 nm, 34 shows the case where the film thickness of the transparent electrode 17 is 140 nm, FIG. 35 shows the film thickness of the transparent electrode 17 of 150 nm, and FIG. 36 shows the film thickness of the transparent electrode 17 of 160 nm.

  As is apparent from the figure, as the film thickness of the transparent electrode 17 changes, the level of light transmittance for each color light changes. In particular, the variation in light transmittance with respect to light having a wavelength of 460 nm (blue light) is remarkable. Looking at FIG. 26 in which the transparent electrode film thickness is 70 nm at the second inorganic alignment film thickness d4 = 65 nm, the average value of the light transmittance for light with a wavelength of 460 nm (blue light) and light with a wavelength of 550 nm (green light) The average value of the light transmittance with respect to is less than 95%, and the decrease in the light transmittance is remarkable. On the other hand, when FIG. 21, FIG. 27 and FIG. 32 in which the transparent electrode film thickness is 120 nm are seen, the light transmittance with respect to each color light can be secured at 97% in any second inorganic alignment film thickness d4. . On the other hand, when FIG. 24, FIG. 30, and FIG. 35 in which the transparent electrode film thickness is 150 nm are observed, the light transmittance with respect to light (blue light) having a wavelength of 460 nm is secured at any second inorganic alignment film thickness d4. On the other hand, when FIG. 25, FIG. 31 and FIG. 36 in which the transparent electrode film thickness is 160 nm are seen, the light transmittance with respect to light (blue light) having a wavelength of 460 nm in any second inorganic alignment film thickness d4. Is less than 95%, and the fluctuation of the light transmittance (the amplitude of the curve in the graph) with respect to the increase or decrease of the second insulating film thickness is extremely large.

  Therefore, it can be said from FIGS. 21 to 36 that the actual film thickness (physical film thickness) dt of the transparent electrode 17 is desirably 120 nm ≦ dt ≦ 150 nm. When this is converted into an optical film thickness rt, the optical film thickness rt of the transparent electrode 17 is preferably 220 nm ≦ rt ≦ 276 nm.

  According to the liquid crystal device 33 of the present embodiment, as described above, the optical film thickness rt of the transparent electrode 17, the optical film thickness r3 of the second insulating film 18, and the optical film thickness r4 of the second inorganic alignment film 19 are optimized. Therefore, high light transmittance can be obtained in any wavelength region of the visible light region, and the light transmittance in each wavelength region becomes relatively uniform. Thereby, a reflective liquid crystal device capable of realizing beautiful white display, good color balance, and bright display can be obtained. Further, since only one insulating film needs to be formed on the transparent electrode 17, the cost can be reduced. In addition, since the physical thickness of the second insulating film 18 is about 40 nm to 190 nm, which is a relatively thick insulating film, flicker and image sticking can be sufficiently reduced.

[Fourth Embodiment]
Hereinafter, a fourth embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the liquid crystal device of this embodiment is the same as that of the third embodiment, and only the configurations of the second insulating film and the second inorganic alignment film are different from those of the third embodiment.
Therefore, in FIG. 37, the same code | symbol is attached | subjected to the same component as FIG. 15, and detailed description is abbreviate | omitted.

In the liquid crystal device 34 of the present embodiment, a silicon oxide film (SiO ₂ ) having a film thickness of 105 nm formed by plasma CVD is used as the second insulating film 28. The refractive index n3 of the second insulating film 28 is 1.46. Further, as the second inorganic alignment film 29, a silicon oxide film (SiO ₂ ) formed by oblique deposition is used. The oblique deposition conditions are such that the degree of vacuum is 5 × 10 ⁻³ Pa and the deposition is performed from a direction inclined 45 degrees from the substrate normal direction to the X-axis direction (see FIG. 37). The refractive index of the second inorganic alignment film 29 in the X-axis direction (refractive index felt by polarized light vibrating in the X-axis direction) nx is 1.40 (= n4 min), and the refractive index in the Y-axis direction (polarized light vibrating in the Y-axis direction). Is assumed to be 1.42 (= n4max). Therefore, the average refractive index n4 of the second inorganic alignment film 29 is 1.41. The actual film thickness (physical film thickness) d4 of the second inorganic alignment film 29 is preferably 30 nm ≦ d4 ≦ 100 nm, for example, 60 nm. The transparent electrode 17 is the same as that of the third embodiment.

  The refractive index nlc of the liquid crystal layer 3 is 1.52. Therefore, in the present embodiment, the magnitude relationship among the refractive index nt of the transparent electrode 17, the refractive index nlc of the liquid crystal layer 3, the refractive index n3 of the second insulating film 28, and the refractive index n4 of the second inorganic alignment film 29 is nt. > Nlc> n3> n4. Further, assuming that the optical thickness of the second inorganic alignment film 29 is r4, r4 = n4 × d4, and therefore r4 is approximately 42 ≦ r2 ≦ 141. In the present embodiment, since the average refractive index n4 of the second inorganic alignment film 29 only needs to satisfy the above magnitude relationship, the larger refractive index nmax (ny) of the second inorganic alignment film 29 is the second insulation. The refractive index n3 of the film 28 may be larger.

  Similar to the third embodiment, the present inventor performed a simulation for comparing the wavelength dependence of the light transmittance with and without the second insulating film 28. The result is shown in FIG. In FIG. 38, the horizontal axis represents the light wavelength [nm], and the vertical axis represents the light transmittance [%] from the second substrate 2 to the liquid crystal layer 3. A broken line curve indicates the case where the second insulating film 28 is not provided, and a solid line curve indicates the case where the second insulating film 28 is provided (actual film thickness d3 = 105 nm).

  Similar to the third embodiment, in the region of wavelength 550 nm (green light), the light transmittance is improved when the second insulating film 28 is present, compared to the case where the second insulating film 28 is not present. In addition, in the region of wavelength 460 nm (blue light) and the region of wavelength 620 nm (red light), the light transmittance is improved when the second insulating film 28 is provided compared to the case where the second insulating film 28 is not provided. The value is close to the light transmittance at a wavelength of 550 nm. That is, flat spectral characteristics are obtained when the second insulating film 28 is provided, compared to when the second insulating film 28 is not provided. In the present embodiment, the light transmittance at each wavelength is further closer than in the third embodiment, and flatter spectral characteristics are obtained. Therefore, it has been found that the effect of the present invention is increased when the refractive index n4 of the second inorganic alignment film 29 is smaller.

  Next, a simulation was performed in which the film thickness of the second inorganic alignment film 29 was changed and the dependence of the light transmittance at each film thickness on the second insulating film thickness was compared. The results are shown in FIGS. 39 to 41, the horizontal axis represents the physical thickness [nm] of the second insulating film 28, and the vertical axis represents the light transmittance [%] from the second substrate 2 to the liquid crystal layer 3. The solid curve is the light transmittance for light with a wavelength of 460 nm (blue light), the dashed curve is the light transmittance for light with a wavelength of 550 nm (green light), and the two-dot chain curve is the light for light with a wavelength of 620 nm (red light). Transmittance. 39 shows the case where the film thickness of the second inorganic alignment film 29 is 30 nm, FIG. 40 shows the film thickness of the second inorganic alignment film 29 is 65 nm, and FIG. 41 shows the film thickness of the second inorganic alignment film 29 is 100 nm.

  As is apparent from FIGS. 39 to 41, the dependency of the light transmittance on the second insulating film thickness shows the same behavior as in the third embodiment, but the variation of the light transmittance with respect to the increase and decrease of the second insulating film thickness is the first. It is larger than the third embodiment. When the optimum range of the film thickness of the second insulating film 28 is judged in the same manner as in the third embodiment, when the film thickness d4 of the second inorganic alignment film 29 shown in FIG. When the thickness d4 of the second inorganic alignment film 29 shown in FIG. 40 is 65 nm, the optimum range d3 of the thickness of the second insulating film 28 is 70 nm ≦ d3 ≦ 150 nm. When the thickness d4 of the second inorganic alignment film 29 shown in 41 is 100 nm, the optimum range d3 of the thickness of the second insulating film 28 is 50 nm ≦ d3 ≦ 130 nm.

  FIG. 42 shows an optimal combination of the film thickness d4 of the second inorganic alignment film 29 and the film thickness d3 of the second insulating film 28. In FIG. 42, the horizontal axis represents the optical film thickness [nm] of the second inorganic alignment film 29, and the vertical axis represents the optical film thickness [nm] of the second insulating film 28. Here, the optical film thickness which is the product of the refractive index of each film and the physical film thickness is used for both the horizontal axis and the vertical axis. That is, the optical film thickness r3 of the second insulating film 28 is represented by r3 = n3 × d3, and the optical film thickness r4 of the second inorganic alignment film 29 is represented by r4 = n4 × d4.

When the optimum range of FIGS. 39 to 41 is written on FIG. 42, the optimum range is set when the optical film thickness r4 of the second inorganic alignment film 29 is set to a range of 50 ≦ r4 ≦ 150, which is a range that is normally used. This is a hatched area sandwiched between two straight lines, a two-dot chain line and a solid line. When the hatched region is expressed by a mathematical expression, the optimum range of the optical film thickness r3 of the second insulating film 28 is
−0.8401 × r4 + 189.76 ≦ r3 ≦ −0.8323 × r4 + 302.7 (4)
It becomes.

  According to the liquid crystal device 34 of the present embodiment, the optical film thickness rt of the transparent electrode 17, the optical film thickness r3 of the second insulating film 28, and the optical film thickness r4 of the second inorganic alignment film 29 are the same as in the third embodiment. Since it is optimized, a high light transmittance can be obtained in any wavelength region, and the light transmittance in each wavelength region becomes uniform. Thereby, a reflective liquid crystal device capable of realizing beautiful white display, good color balance, and bright display can be obtained. Further, since only one insulating film needs to be formed on the transparent electrode 17, the cost can be reduced. In addition, since the physical thickness of the second insulating film 28 is about 50 nm to 180 nm and becomes a relatively thick insulating film, flicker and image sticking can be sufficiently reduced.

[Projector embodiment]
Hereinafter, an embodiment of the projector of the present invention will be described with reference to FIG. FIG. 43 is a schematic configuration diagram of the projector according to the present embodiment.

  The projector 700 according to the present embodiment includes a polarization illumination device 100 that is schematically configured by a light source unit 110, an integrator lens 120, and a polarization conversion element 130 arranged along the system optical axis L, and S-polarized light emitted from the polarization illumination device 100. The polarization beam splitter 200 that reflects the light beam by the S polarization reflection surface 201, and the dichroic mirror 412 that separates the blue light (B light) component from the light reflected from the S polarization reflection surface 201 of the polarization beam splitter 200, is separated. Light modulation element 300B that modulates blue light, dichroic mirror 413 that reflects and separates red light (R light) component out of the luminous flux after blue light is separated, and light modulation that modulates the separated red light Light modulation element 3 that modulates the remaining green light that passes through element 300R and dichroic mirror 413 0G, projection optical system including a projection lens that synthesizes light modulated by the three light modulation elements 300R, 300G, and 300B by the dichroic mirrors 412 and 413 and the polarization beam splitter 200 and projects the synthesized light on the screen 600 500. The liquid crystal devices of the first to fourth embodiments are used for the light modulation elements 300R, 300G, and 300B.

  According to the present embodiment, since the liquid crystal devices of the first to fourth embodiments having uniform and high light reflectance are used for the light modulation elements 300R, 300G, and 300B, a projector having excellent display quality can be obtained. Can be realized.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. In the above description, the configuration on the first substrate (element substrate) side in the first and second embodiments and the configuration on the second substrate (counter substrate) side in the third and fourth embodiments are separately described. Any embodiment may be combined for the entire apparatus. However, the combination of the first embodiment and the third embodiment, the second embodiment, and the fourth embodiment is preferable from the viewpoint of sharing the film formation conditions of the inorganic alignment film on both the substrates. From the viewpoint of obtaining a higher effect of the present invention, a combination of the second embodiment and the fourth embodiment is preferable.

  The element substrate used as the first substrate is not limited to the TFT substrate, and may be a TFD substrate using a thin film diode (abbreviated as TFD) as a pixel switching element. Alternatively, the present invention may be applied to a passive matrix liquid crystal device having no pixel switching element. Further, the reflective electrode may be an electrode having a function of a so-called transflective plate that reflects a part of incident light and transmits a part of the incident light in addition to the one that reflects substantially all of the incident light. In addition, specific descriptions of materials, film thicknesses, refractive indexes, manufacturing methods, and the like of the various films mentioned in the above embodiment are merely examples, and can be changed as appropriate.

  DESCRIPTION OF SYMBOLS 1 ... 1st board | substrate, 2 ... 2nd board | substrate, 3 ... Liquid crystal layer, 4 ... Reflective electrode, 5,15 ... 1st insulating film, 6,16 ... 1st inorganic alignment film, 7, 17 ... Transparent electrode, 8, DESCRIPTION OF SYMBOLS 19, 29 ... 2nd inorganic alignment film, 18, 28 ... 2nd insulating film, 31, 32, 33, 34 ... Liquid crystal device, 110 ... Light source part, 300R, 300G, 300B ... Light modulation element, 500 ... Projection optical system 700 ... Projector.

Claims (10)

A first substrate;
A second substrate having optical transparency disposed opposite to the first substrate;
A liquid crystal layer sandwiched between the first substrate and the second substrate;
A reflective electrode disposed on a side of the first substrate facing the second substrate;
A first insulating film disposed on the reflective electrode;
A first inorganic alignment film disposed on the first insulating film,
When the refractive index of the liquid crystal layer is nlc, the refractive index of the first insulating film is n1, and the refractive index of the first inorganic alignment film is n2,
nlc>n2> n1,
When the optical film thickness of the first inorganic alignment film is r2,
50 ≦ r2 ≦ 150,
When the optical film thickness of the first insulating film is r1,
−1.0173 × r2 + 367.29 ≦ r1 ≦ −1.0197 × r2 + 463.34
A liquid crystal device characterized by the above.   The first inorganic alignment film has an anisotropy in the refractive index viewed from the normal direction of the substrate, and nlc> n2max> n1 when the larger one of the two refractive indexes is n2max. The liquid crystal device according to claim 1, wherein the relationship is satisfied. A first substrate;
A second substrate having optical transparency disposed opposite to the first substrate;
A liquid crystal layer sandwiched between the first substrate and the second substrate;
A reflective electrode disposed on a side of the first substrate facing the second substrate;
A first insulating film disposed on the reflective electrode;
A first inorganic alignment film disposed on the first insulating film,
When the refractive index of the liquid crystal layer is nlc, the refractive index of the first insulating film is n1, and the refractive index of the first inorganic alignment film is n2,
nlc>n1> n2,
When the optical film thickness of the first inorganic alignment film is r2,
50 ≦ r2 ≦ 150,
When the optical film thickness of the first insulating film is r1,
−0.7651 × r2 + 325.61 ≦ r1 ≦ −0.7587 × r2 + 429.96
A liquid crystal device characterized by the above.   The first inorganic alignment film has an anisotropy in the refractive index viewed from the normal direction of the substrate, and nlc> n1> n2max, where n2max is the larger refractive index of the two refractive indexes. The liquid crystal device according to claim 3, wherein the relationship is satisfied. A first substrate;
A second substrate having optical transparency disposed opposite to the first substrate;
A liquid crystal layer sandwiched between the first substrate and the second substrate;
A reflective electrode disposed on a side of the first substrate facing the second substrate;
A transparent electrode disposed on a side of the second substrate facing the first substrate;
A second insulating film disposed on the transparent electrode;
A second inorganic alignment film disposed on the second insulating film,
When the refractive index of the liquid crystal layer is nlc, the refractive index of the transparent electrode is nt, the refractive index of the second insulating film is n3, and the refractive index of the second inorganic alignment film is n4,
nt>nlc>n4> n3,
When the optical film thickness of the transparent electrode is rt,
220 ≦ rt ≦ 276,
When the optical film thickness of the second inorganic alignment film is r4,
50 ≦ r4 ≦ 150,
When the optical film thickness of the second insulating film is r3,
−1.0189 × r4 + 212.05 ≦ r3 ≦ −1.016 × r4 + 325.64
A liquid crystal device characterized by the above.   The second inorganic alignment film has an anisotropy in the refractive index viewed from the substrate normal direction, and nt> nlc> n4max> when the larger one of the two refractive indices is n4max. The liquid crystal device according to claim 5, wherein the relationship n3 is satisfied. A first substrate;
A second substrate having optical transparency disposed opposite to the first substrate;
A liquid crystal layer sandwiched between the first substrate and the second substrate;
A reflective electrode disposed on a side of the first substrate facing the second substrate;
A transparent electrode disposed on a side of the second substrate facing the first substrate;
A second insulating film disposed on the transparent electrode;
A second inorganic alignment film disposed on the second insulating film,
When the refractive index of the liquid crystal layer is nlc, the refractive index of the transparent electrode is nt, the refractive index of the second insulating film is n3, and the refractive index of the second inorganic alignment film is n4,
nt>nlc>n3> n4,
When the optical film thickness of the transparent electrode is rt,
220 ≦ rt ≦ 276,
When the optical film thickness of the second inorganic alignment film is r4,
50 ≦ r4 ≦ 150,
When the optical film thickness of the second insulating film is r3,
−0.8401 × r4 + 189.76 ≦ r3 ≦ −0.8323 × r4 + 302.7
A liquid crystal device characterized by the above.   The second inorganic alignment film has an anisotropy in the refractive index viewed from the normal direction of the substrate, and nt> nlc> n3> when the larger one of the two refractive indices is n4max. The liquid crystal device according to claim 7, wherein the relationship of n4max is satisfied.   The first insulating film or the second insulating film is a silicon oxide film formed by a CVD method or an evaporation method, and the first inorganic alignment film or the second inorganic alignment film is formed by an oblique evaporation method. 9. The liquid crystal device according to claim 1, wherein the liquid crystal device is a silicon oxide film. A light source, a light modulation element that modulates light from the light source, and a projection optical system that projects an image formed by the light modulation element,
A projector, wherein the light modulation element includes the liquid crystal device according to any one of claims 1 to 9.

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