JP2020064192A - Liquid crystal optical modulator, liquid crystal display device and holography device - Google Patents

Abstract

To provide a liquid crystal optical modulator that constitutes a liquid crystal display device which can perform display in which a pixel is fine and has high contrast.SOLUTION: A liquid crystal optical modulator 10 comprises: a transparent substrate 5; a counter electrode 4 made of a transparent electrode film; a liquid crystal layer 20; a pixel electrode 3 provided for each two-dimensionally arranged pixel; and a circuit board having a driving circuit connected to each of the pixel electrodes 3 in descending order. A projecting part 4r having an inclined plane is formed along a center line of the pixels on an undersurface of the counter electrode 4 such that thickness of the liquid crystal layer 20 is minimum at a center of the pixels, and a recessed part surrounded by the projecting part 4r is provided for each pixel.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a liquid crystal light modulator, and a liquid crystal display device and a holography device using the liquid crystal light modulator.

  A spatial light modulator (SLM: Spatial Light Modulator) is a device that spatially modulates the phase and amplitude of light by two-dimensionally arraying optical elements (light modulators) as pixels in a matrix. Widely used in the fields of recording technology, laser processing, etc. A spatial light modulator is, for example, one that applies a liquid crystal or magneto-optical material to an optical element to change (rotate) the polarization direction of light, or a movable minute mirror is provided for each pixel to reflect light. A DMD (Digital Mirror Device) system that changes the direction has been developed. Among them, liquid crystals that have a large optical rotation angle, that is, a high degree of light modulation and that can be manufactured relatively easily are widely applied, and in order to obtain a high-definition liquid crystal display (LCD), miniaturization of pixels is performed. Is being researched about.

Here, a liquid crystal optical element (liquid crystal optical element) will be briefly described with reference to FIG. As schematically shown in FIG. 4, the liquid crystal optical element 1 includes a liquid crystal layer 20, a pair of electrodes 3 and 4 for applying a vertical voltage to the liquid crystal layer 20, and a liquid crystal layer 20 which is in contact with the upper and lower sides of the liquid crystal layer 20, respectively. The alignment films 21 and 22 provided are provided. When a voltage is applied from the electrodes 3 and 4 and an electric field E is generated in the liquid crystal layer 20, the orientation of the rod-shaped liquid crystal molecules 2 changes. The liquid crystal optical element 1 shown in FIGS. 4A and 4B is of a vertical alignment (VA: Vertical Alignment) system, and the liquid crystal molecules 2 stand upright with respect to the alignment films 21 and 22 in a non-electric field state. The liquid crystal molecule 2 is tilted by the electric field E in the direction (indicated by a downward arrow in FIG. 4B). Then, the light L transmitted through the liquid crystal layer 20 in which the liquid crystal molecules 2 are vertically erected is not modulated, while the light L transmitted through the liquid crystal layer 20 in which the liquid crystal molecules 2 are horizontally tilted has its polarization direction rotated. Emit. The liquid crystal molecule 2 has a length of several nm and is exaggerated in FIG. 4 and FIG. 34 described later. In FIG. 4, the electrodes 3 and 4 are made of a transparent electrode material so that the liquid crystal optical element 1 transmits light, and two polarizers 82 and 81 are arranged in crossed Nicols above and below the liquid crystal optical element 1. Then, natural light (non-polarized light) _LuP from above is transmitted through the polarizer 82 and is incident on the liquid crystal optical element 1 as light L having one polarization component. The light emitted from the liquid crystal optical element 1 to which the voltage is not applied is blocked by the polarizer (analyzer) 81 to be dark (black) display, and the light emitted from the liquid crystal optical element 1 to which the voltage is applied is Since the direction of the polarized light is rotated by 90 °, the light is transmitted through the polarizer 81 and bright (white) display is performed. Note that when the electric field E is weak, the tilt angle of the liquid crystal molecules 2 is small, and the optical rotation angle of the light L is less than 90 °. Therefore, a part is blocked by the polarizer 81, and halftone display is performed.

  A spatial light modulator (hereinafter, referred to as a liquid crystal light modulator) 110 having such a liquid crystal optical element 1 as an optical element has, for example, a circuit configuration shown in FIG. 3 as an active matrix drive type spatial light modulator. . To this end, the liquid crystal light modulator 110, as schematically shown in FIG. 34, has a liquid crystal layer 20 with respect to the counter electrode 104 which is a transparent electrode film provided on the entire surface above the liquid crystal layer 20 with the transparent substrate 105 as a base. A pixel electrode 103 for each pixel is provided on the lower side of 20 with an insulating layer 6 interposed therebetween, and a Si substrate (not shown) having a drive circuit 7 connected to the pixel electrode 103 is further provided on the lower side thereof. That is, the liquid crystal light modulator 110 is an LCOS (Liquid Crystal On Silicon) -SLM, and light incident from above passes through the transparent substrate 105, the counter electrode 104, and the liquid crystal layer 20, and is a pixel electrode made of a metal electrode material. It is a reflection type spatial light modulator that reflects at 103 and emits upward, and light passes back and forth through the liquid crystal layer 20 (for example, Patent Document 1). In the LCOS type liquid crystal light modulator, the drive circuit 7 and the wirings 71, 72, 73 connected to the drive circuit 7 can be arranged so as to overlap the pixel electrode 103 in a plan view, and further, the transistor 7t of the drive circuit 7 can be arranged. Since it is formed of a MOSFET (metal oxide semiconductor field effect transistor), miniaturization of pixels is realized up to a pitch of several μm.

  In the liquid crystal light modulator 110, the pixel electrode 103 of the pixel selected by the signal line 71 and the scanning line 72 has a potential of + (positive) or − (negative) (+ in FIG. 34), and becomes GND (0 V). Since the vertical electric field E is generated between the counter electrode 104 and the connected counter electrode 104, the orientation of the liquid crystal molecules 2 changes in the region sandwiched between the counter electrode 104 and the specific pixel electrode 103. However, since the pixel electrodes 103 are provided at intervals, a region where the electric field E is not generated exists along the boundary line between the pixels. In such a plan view, a region without the pixel electrode 103 is shielded from light by a non-opening portion, for example, a lattice-shaped black matrix. Since the liquid crystal light modulator is generally driven by an alternating current (AC) power source, the generated electric field alternates upward and downward every frame.

The spatial light modulator requires further miniaturization (narrow pitch) of the pixel size (pitch) for application to an electronic holography device and so on. It is desired that the thickness be less than 4 μm. However, in the liquid crystal light modulator, when pixels are miniaturized, electric field crosstalk is likely to occur, and display contrast is reduced. More specifically, since the counter electrode 104 is formed to be wider than the pixel electrode 103 partitioned for each pixel, as shown in FIG. 34, the counter electrode 104 spreads out to some extent from the pixel electrodes 103 of the bright display pixels 111 and 113. A weak electric field E _L is also generated diagonally toward the counter electrode 104. When the pixel pitch is narrow, the electric field E _L reaches the opening of the adjacent dark-display pixel 112 beyond the non-opening. Further, the gap between the adjacent pixel electrodes 103, 103 is also narrowed, so that the electric field E in the in-plane direction from the pixel electrode 103 of the pixels 111, 113 to the pixel electrode 103 of the pixel 112 having the same potential (0 V) as the counter electrode 104. _IP (lateral electric field) leaks. The leak electric fields E _L and E _IP cause the liquid crystal molecules 2 to tilt also in the pixel 112. As a result, the pixel 112 is in a state called black floating, which does not completely display dark (0%) even in the opening. In order to prevent such black floating of the dark display pixels of the liquid crystal light modulator 110, the brightness of the light source may be reduced, but this is not desirable because the brightness of the bright display pixels is reduced.

  In order to suppress the electric field crosstalk in the liquid crystal light modulator, a driving unit that sequentially corrects the video signal of each pixel so that the potential difference between adjacent pixel electrodes becomes smaller is disclosed (for example, Patent Document 2). ). In Patent Document 2, a voltage difference applied to a certain pixel and a voltage difference to an adjacent pixel is detected, and when the potential difference is larger than a predetermined threshold value, application to the adjacent pixel is performed using a correction table created in advance. A configuration for changing the voltage is shown.

  Further, there is disclosed a liquid crystal light modulator in which a wall for partitioning a liquid crystal layer is formed by a dielectric in a gap between pixels adjacent in one direction (Non-Patent Document 1). Since the leakage electric field from the pixel adjacent to the opening of the dark display pixel that separates the dielectric wall is suppressed, the quality of the dark display can be improved (closer to 0%).

Japanese Patent No. 4643786 Japanese Patent No. 5045278

Yoshitomo Isomae, Yosei Shibata, Takahiro Ishinabe, Hideo Fujikake, "Design of 1-μm-pitch liquid crystal spatial light modulators having dielectric shield wall structure for holographic display with wide field of view", Optical Review, Volume 24, Issue 2, pp 165-176, April 2017

  In the method of driving the liquid crystal light modulator described in Patent Document 2, it is necessary to prepare in advance correction data specific to the liquid crystal light modulator. For example, when a liquid crystal light modulator is produced, an optimum correction amount is determined while displaying a test signal, and it is necessary to create the liquid crystal light modulator for each type of liquid crystal light modulator. Further, the lateral electric field can be suppressed, but the oblique leakage electric field spreading toward the counter electrode cannot be suppressed.

  In the liquid crystal light modulator described in Non-Patent Document 1, since the dielectric wall has the same thickness as the liquid crystal layer having a thickness of 1 to several μm, the width becomes narrower than 1 μm when the pixel pitch becomes several μm or less. Thus, the aspect ratio becomes over 1 to about 10. In the manufacture of a liquid crystal light modulator, it is difficult to accurately form such a minute member having a high aspect ratio and uniformly fill the liquid crystal in the gap partitioned by each pixel. Therefore, there is a possibility that the unevenness of the liquid crystal density and the variation of the contrast due to the dimension error of the shape of the dielectric wall may increase.

  The present invention has been made in view of the above problems, and constitutes a liquid crystal display device capable of high-contrast display with fine pixels, a holography device having a sufficiently wide viewing angle, these liquid crystal display devices, and the like. An object is to provide a liquid crystal light modulator.

  That is, the liquid crystal light modulator according to the present invention includes a transparent substrate, a transparent electrode film, a liquid crystal layer, a pixel electrode provided for each pixel that is two-dimensionally arranged in the x direction and the y direction, and the pixel electrode. And a circuit board having a drive circuit connected to each other in order from the top, and in the x direction on the lower surface of the transparent electrode film so that the thickness of the liquid crystal layer becomes minimum at the center between pixels adjacent in the x direction. The structure is such that a convex portion having an inclined inclined surface is formed along the y direction. Alternatively, in the liquid crystal light modulator, a convex portion having an inclined surface is formed on the lower surface of the transparent electrode film so that the thickness of the liquid crystal layer becomes the minimum at the center between adjacent pixels, and the convex portion is formed. A recess surrounded by the part may be provided for each pixel.

  With such a configuration, in the liquid crystal light modulator, the convex portion of the transparent electrode film, which is the counter electrode, blocks the electric field between the pixels, so that the electric field is suppressed from leaking to the opening of the dark display pixel.

  A liquid crystal display device according to the present invention includes the liquid crystal light modulator and a polarizer arranged above the liquid crystal light modulator, and is irradiated with light from above to display an image above. Alternatively, the liquid crystal display device according to the present invention includes the liquid crystal light modulator and two polarizers arranged on the upper side and the lower side of the liquid crystal light modulator, and is irradiated with light from either the upper side or the lower side. And display the image on the other side. With this configuration, the liquid crystal display device can sufficiently darken the dark display pixel adjacent to the bright display pixel.

  A holographic device according to the present invention includes the liquid crystal display device, a light source for irradiating the liquid crystal display device with light, and a power supply connected to a drive circuit and a counter electrode of a liquid crystal light modulator of the liquid crystal display device. With such a configuration, the holographic device can display a dark display pixel without blackening.

  According to the liquid crystal light modulator and the liquid crystal display device of the present invention, high-contrast display is possible even if the pixels are minute. According to the holography device of the present invention, a wide viewing angle can be displayed.

FIG. 3 is an external view illustrating the structure of the liquid crystal light modulator according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating the structure of the liquid crystal light modulator according to the first embodiment of the present invention. It is an equivalent circuit schematic of a liquid crystal light modulator. 6A and 6B are schematic diagrams for explaining the operation of the liquid crystal optical element in the liquid crystal light modulator, where FIG. 7A is when no voltage is applied, and FIG. FIG. 3 is an external view illustrating the shape of a counter electrode of the liquid crystal light modulator according to the first embodiment of the present invention. FIG. 6 is a cross-sectional view schematically illustrating a step of forming a counter electrode in the method of manufacturing a liquid crystal light modulator according to the present invention. It is a schematic diagram explaining operation | movement of the liquid crystal light modulator which concerns on this invention, and is sectional drawing of the liquid crystal light modulator shown in FIG. FIG. 9 is an external view illustrating the shape of the counter electrode of the liquid crystal light modulator according to the modification of the first embodiment of the present invention. FIG. 9 is an external view illustrating the shape of the counter electrode of the liquid crystal light modulator according to the modification of the first embodiment of the present invention. 3 is an external view illustrating the structure of the liquid crystal display device according to the embodiment of the present invention. FIG. It is a schematic diagram explaining the structure of the holography device which concerns on this invention. It is sectional drawing explaining the structure of the liquid crystal light modulator which concerns on 2nd Embodiment of this invention. FIG. 8 is an external view illustrating the shape of a counter electrode of the liquid crystal light modulator according to the second embodiment of the present invention. FIG. 11 is an external view illustrating the shape of a counter electrode of a liquid crystal light modulator according to a modification of the second embodiment of the present invention. FIG. 11 is an external view illustrating the shape of a counter electrode of a liquid crystal light modulator according to a modification of the second embodiment of the present invention. FIG. 11 is a cross-sectional view illustrating the shape of a counter electrode of a liquid crystal light modulator according to a modification of the second embodiment of the present invention. It is an external view explaining the structure of the liquid crystal light modulator which concerns on 3rd Embodiment of this invention. FIG. 6 is an external view illustrating the structure of a liquid crystal display device according to another embodiment of the present invention. FIG. 5 is a plan view illustrating the shapes of the pixel electrode and the counter electrode of the example, and the observation position of the simulation. 3 is a potential distribution and liquid crystal alignment of a sample having a cell thickness of 1 μm according to the first embodiment. 7 is a potential distribution and a liquid crystal alignment of a sample of Comparative Example having a cell thickness of 1 μm. FIG. 3 is a two-dimensional distribution diagram of reflectance of a sample having a cell thickness of 1 μm, where (a) is a sample according to the first embodiment, (b) is a sample according to a modification of the first embodiment, and (c) is a comparison. Here is an example. 3 is a potential distribution and liquid crystal alignment of a sample having a cell thickness of 1.5 μm according to the first embodiment. 3 is a potential distribution and a liquid crystal alignment of a sample of a comparative example having a cell thickness of 1.5 μm. It is a two-dimensional distribution diagram of reflectance of a sample having a cell thickness of 1.5 μm, (a) is a sample according to the first embodiment, and (b) is a comparative example. 6 is a reflectance distribution of samples according to the first embodiment and a comparative example. 6 is a graph showing the height dependence of the convex portion of the opposite electrode of the reflectance and the contrast ratio at the center of the pixel for bright display and dark display. 3 is a potential distribution and liquid crystal alignment of a sample having a cell thickness of 1 μm and a width of a convex portion of a counter electrode of 300 nm according to the second embodiment. 3 is a potential distribution and liquid crystal alignment of a sample having a cell thickness of 1 μm and a width of a convex portion of a counter electrode of 400 nm according to the second embodiment. 3 is a potential distribution and a liquid crystal alignment of a sample having a cell thickness of 1 μm and a width of a convex portion of a counter electrode of 600 nm according to the second embodiment. It is a two-dimensional distribution diagram of the reflectance of the sample with a cell thickness of 1 μm according to the second embodiment, in which the width of the convex portion of the counter electrode is 300 nm for (a), 400 nm for (b), and 600 nm for (c). is there. 5 is a reflectance distribution of a sample having a cell thickness of 1 μm, a height of a convex portion of a counter electrode of 300 nm according to the first and second embodiments, and a comparative sample having a cell thickness of 1 μm. 6 is a graph showing the width dependence of the convex portion of the counter electrode of the reflectance and the contrast ratio at the center of a pixel for bright display and dark display. It is sectional drawing of the conventional liquid crystal light modulator.

  A mode for realizing a liquid crystal light modulator and a liquid crystal display device according to the present invention will be described with reference to the drawings. The liquid crystal light modulator and its elements shown in the drawings may be exaggerated in size, positional relationship and the like for the sake of clarity, and may be simplified in shape.

[First Embodiment: Liquid Crystal Light Modulator]
In the liquid crystal light modulator 10 according to the first embodiment of the present invention, pixels (liquid crystal optical elements) are two-dimensionally arranged in the X direction and the Y direction, and as shown in FIG. 1 and FIG. A Si substrate (circuit board) on which a counter electrode (transparent electrode film) 4 sandwiching the layer 20 from above and below, a pixel electrode 3 provided for each pixel, and a drive circuit 7 (see FIG. 3) connected to the pixel electrode 3 are formed. 70 and the uppermost transparent substrate 5 are provided, and the lower surface of the counter electrode 4 is provided with unevenness so as to have a depression for each pixel. The liquid crystal light modulator 10 further includes alignment films 21 and 22 provided in contact with the upper and lower sides of the liquid crystal layer 20, signal lines (source lines) 71 extending in the Y direction on the Si substrate 70, and extending in the X direction. The scanning lines (gate lines) 72 and the common electrode lines (common lines) 73 (wirings 71, 72, 73 collectively provided), the light shielding film 74 for blocking light to the Si substrate 70, the pixel electrodes 3 and the wirings 71, An insulating layer 6 that insulates the layers 72 and 73 is provided. That is, the liquid crystal light modulator 10 includes, in order from the top, the transparent substrate 5, the counter electrode 4, the alignment film 21, the liquid crystal layer 20, the alignment film 22, the pixel electrode 3, the insulating layer 6, the light shielding film 74, and the wirings 71, 72. 73 and a Si substrate 70. In FIG. 1, the liquid crystal layer 20 and the alignment film 22 are transparent, and the interface between the alignment film 22 and the liquid crystal layer 20 is indicated by a broken line. 1 shows a cross section along the Y direction including the pixel center, and FIG. 2 shows a cross section along the X direction including the pixel center. The liquid crystal light modulator 10 is a reflective spatial light modulator that reflects light emitted from above and emits the light upward, and changes the polarization direction of the light in the pixel selected at that time.

  The liquid crystal light modulator 10 is an active matrix drive type spatial light modulator, and as an example, as shown in FIG. 3, the drive circuit 7 for each pixel includes a transistor 7t and a storage capacitor 7c. The transistor 7t has a source connected to the signal line 71, a gate connected to the scanning line 72, and a drain connected to the pixel electrode 3 side of the liquid crystal optical element 1. The storage capacitor 7c has one terminal connected to the drain of the transistor 7t and the liquid crystal optical element 1, and the other terminal connected to the GND via the common electrode line 73.

A pixel of the liquid crystal light modulator 10 has a rectangular shape in a plan view (indicating an XY plane), and is a rectangle long in the Y direction in the present embodiment, but the invention is not limited to this, and may be depending on an application of the liquid crystal light modulator 10. The aspect ratio is designed to be about 1 to 3. The pixel size (pitch) is designed according to the application of the liquid crystal light modulator 10 or the like, but at least the X-direction length (short side length) p _X is preferably 4 μm or less, and preferably 3 μm or less. More preferably, it is even more preferably 2 μm or less. In particular, when the liquid crystal light modulator 10 is applied to an electronic holography device, it is preferable that the pixel (p _X , p _Y ) is small in order to increase the viewing angle. Hereinafter, each element constituting the liquid crystal light modulator according to this embodiment will be described in detail.

(Liquid crystal layer)
The liquid crystal layer 20 is made of a liquid crystal material, and may be a known material that is applied to a display device of a liquid crystal display such as a twisted nematic (TN) type or a vertical alignment (VA) type. The liquid crystal layer 20 is preferably a VA mode, which has a relatively wide viewing angle and is excellent in dark display. Therefore, a liquid crystal having a negative dielectric anisotropy (n-type liquid crystal) is applied. As described above with reference to FIG. 4, in the liquid crystal layer 20, the liquid crystal molecules 2 stand vertically (Z direction) in the non-electric field state (initial state), and the liquid crystal molecules 2 are tilted by the electric field E in the vertical direction. The orientation of such liquid crystal molecules 2 is mainly controlled by the alignment films 21 and 22. The thickness (cell thickness) d of the liquid crystal layer 20 is designed in the range of about 0.5 to 5 μm according to the liquid crystal material or the like so that desired optical characteristics can be obtained. The response speed of the modulator 10 becomes high. On the other hand, when the cell thickness d is large with respect to the pixel size, the leakage electric field E _{L in} the oblique direction (see FIG. 34) becomes strong, and the electric field leakage can be sufficiently suppressed even in combination with the shape of the lower surface of the counter electrode 4. Becomes difficult. Specifically, the cell thickness d is preferably 2 μm or less, more preferably 1.5 μm or less, and 1.5 times or less the X-direction length (short side length) p _X. Is preferable, and it is more preferable that it is 1 time or less. In the present embodiment, the cell thickness d is the thickness of the liquid crystal layer 20 at the center of the maximum pixel.

  Note that, as will be described in detail as an operation of the liquid crystal display device described later, in the liquid crystal layer 20, the liquid crystal molecules 2 are tilted as shown in FIG. 4B due to the optical anisotropy of the liquid crystal molecules 2 ( (Non-perpendicular), a phase difference δ occurs due to the polarization component of the transmitted light. Therefore, the linearly polarized light transmitted through the liquid crystal layer 20 shown in FIG. 4B is circularly polarized (when the phase difference δ is an odd multiple of π / 2) or elliptical except when the phase difference δ is an integral multiple of π. It becomes polarized light. It should be noted that FIG. 4B simply shows linearly polarized light that is rotated by 90 °. The liquid crystal layer 20 preferably has a phase difference δ of π when the liquid crystal molecules 2 are completely tilted by the application of the maximum drive voltage (see FIG. 4B), and the liquid crystal light modulator 10 according to the present embodiment. Is a reflection type spatial light modulator, it is preferable that the cell thickness d is such that the phase difference δ is ½ of half.

(Pixel electrode)
The pixel electrode 3 is provided for each pixel in order to generate an electric field in the vertical direction in the liquid crystal layer 20 only in the selected pixel, and is a contact portion (not shown) penetrating the insulating layer 6 to form a surface layer of the Si substrate 70. Connected to the drive circuit 7 formed in. Since the pixel electrodes 3 are provided with gaps l _gX and l _gY (collectively, the gap l _g ) therebetween, in the present embodiment, the shape in plan view is formed into a rectangle that is slightly smaller than the pixel. In a plan view, a region where the pixel electrode 3 is provided in the pixel is called an opening, and a region outside the region is called a non-opening. The wider the gap l _g between the adjacent pixel electrodes 3 and 3, the more easily the leakage electric field (horizontal electric field) E _IP between the pixel electrodes 3 and 3 of the bright display pixel and the adjacent dark display pixel is suppressed. On the other hand, if the gap l _g is wide, the size of the pixel electrode 3 in plan view becomes small, and the aperture ratio of the pixel becomes low. Therefore, the gap l _g is designed so that the leakage electric field E _IP is further suppressed while ensuring the aperture ratio of the pixel together with the cell thickness d and the shape of the convex portion 4r on the lower surface of the counter electrode 4. Is preferred.

  The liquid crystal light modulator 10 is a reflective spatial light modulator, and since the pixel electrode 3 does not need to transmit light, metals such as Cu, Al, Au, Ag, Ta, Cr, Pt, Ru, and the like are used. It is formed of a general metal electrode material such as an alloy, and two or more kinds of the above metals or alloys may be laminated. In particular, it is preferable to apply a material having good adhesion to the alignment film 22 to the uppermost layer. Further, the pixel electrode 3 is preferably provided with a material having a high light reflectance in a sufficient thickness so that the light incident on the pixel electrode 3 has a high reflectance. Materials with good adhesion having a thickness of 10 nm may be laminated. The metal electrode material is processed into a desired plan-view shape by a known method such as a sputtering method, film formation, photolithography, etching or a lift-off method.

(Counter electrode)
The counter electrode 4 is an electrode shared by all the pixels of the liquid crystal light modulator 10, and is provided as an integrally continuous film. Further, the counter electrode 4 has a concave and convex surface on the lower surface facing the liquid crystal layer 20, and as shown in FIG. 5 with the lower surface facing upward, a concave portion whose inner wall surface is an isosceles triangle of four side surfaces of a quadrangular pyramid is a pixel. It is formed every time and has a concave apex at the center of the pixel. Therefore, the counter electrode 4 has a convex ridge line on the inter-pixel center line (represented by a one-dot chain line in FIG. 5) in each of the X direction and the Y direction, and the thickness of the liquid crystal layer 20 is minimum at the inter-pixel center. . In other words, the unevenness on the lower surface of the counter electrode 4 has the ridge-shaped convex portions 4r along the X direction and the Y direction between the pixels so as to surround the concave vertex at the center of the pixel. The convex portion 4r has an inclined surface and has a cross-sectional shape of an isosceles triangle with the bottom side facing upward (the transparent substrate 5 side).

Since the counter electrode 4 is formed so as to project at the center between the pixels, leakage of an electric field is suppressed as described later. In order to sufficiently obtain this effect, the height h of the convex portion 4r (the maximum value of the height difference due to the unevenness) h is preferably 20% or more of the cell thickness d, more preferably 30% or more, The larger the value, the higher the effect. However, even if the height h of the convex portion 4r exceeds 70% of the cell thickness d and becomes large, it is difficult to further improve the effect. Therefore, it is preferably 70% or less. Further, when the height h of the convex portion 4r becomes large, the aspect ratio of the convex portion 4r (the ratio of the height h to the width w _r of the convex portion 4r) becomes high, and it becomes difficult to form the concavities and convexities of the counter electrode 4, Furthermore, since the gradient (2h / w _r ) of the lower surface of the counter electrode 4 becomes steep (close to vertical), it may be difficult to form the alignment film 21 that covers it. The width w _r of the convex portion 4 _r is the length of the base of the isosceles triangle in cross section, which is the maximum width, and in the present embodiment, matches the pixel lengths p _X and p _Y, and the width in the X direction. the width w _rY in w _rX and Y directions are different _{(w rX = p X, w} rY = p Y). Further, as will be described later, the liquid crystal molecules 2 of the liquid crystal layer 20 stand upright on the film surfaces of the alignment films 21 and 22 in the non-electric field state. Therefore, if the aspect ratio of the convex portion 4r is high, the slope (2h / w _r ) of the lower surface of the counter electrode 4 becomes steep, and the liquid crystal molecules 2 are greatly inclined near the counter electrode 4 (the convex portion 4r). , The dark display does not become dark enough. Also, the height h of the convex portion 4r is large difference in height h _a of the counter electrode 4 (see FIG. 1) is increased at the opening, when the opening height difference h _a is large cell thickness d ratio, the pixel electrode 3-Regarding the distance between the counter electrodes 4 and the thickness of the liquid crystal layer 20, the relative difference between the pixel center and the peripheral edge of the opening becomes large. Therefore, when a voltage is applied, the optical rotation angle becomes small at the periphery of the opening having a short optical path length, or the electric field is weakened at the center of the pixel so that the liquid crystal molecules 2 do not fall at a sufficient tilt angle. The unevenness of brightness will occur in the opening). Specifically, it is preferable that the aspect ratio of the protrusions 4r is 1 or less (h ≦ w _r), more preferably from 1/2 or less _{(2h ≦ w r), 1} /3 or less (3h ≦ more preferably w _r ). The counter electrode 4 has a thickness capable of ensuring necessary conductivity at the center of the pixel, which is the thinnest portion.

Since the counter electrode 4 is provided on the light incident side of the liquid crystal light modulator 10, it is formed of a transparent electrode material so as to transmit light. Examples of the transparent electrode material include indium zinc oxide (IZO), indium tin oxide (ITO), tin oxide (SnO ₂ ), antimony oxide-tin oxide (ATO), and oxide. It is made of a known conductive oxide such as zinc (ZnO), fluorine-doped tin oxide (FTO), indium oxide (In ₂ O ₃ ). These transparent electrode materials are formed into a film by a known method such as a sputtering method, a vacuum evaporation method, a coating method, etc., and as will be described later, irregularities are formed on the surface (lower surface) by nanoimprint lithography (NIL) and etching. Alternatively, a conductive polymer such as PEDOT / PSS (Poly (3,4-ethylenedioxythiophene) / poly (4-styrenesulfonate)) may be applied, and the projections and depressions may be directly transferred using a mold for molding.

(Alignment film)
The alignment films 21 and 22 are provided in contact with the upper and lower sides of the liquid crystal layer 20 in order to control the orientation of the liquid crystal molecules 2. The alignment films 21 and 22 are organic films such as polyimide or inorganic films such as Si oxide (SiO _x ), and known materials corresponding to the display system are applied to the alignment films 21 and 22 and formed to a film thickness of several tens to 100 nm. It The alignment film 21 formed so as to cover the counter electrode 4 is formed to have a uniform thickness along the unevenness on the lower surface of the counter electrode 4. On the other hand, it is preferable that the surface of the alignment film 22 (the surface in contact with the liquid crystal layer 20) is formed flat. In the present embodiment, as the VA method, the alignment films 21 and 22 have a hydrophobic group-introduced polyimide or SiO _x (x = 1 to 2) so that the liquid crystal molecules 2 are erected perpendicularly to the film surface in the initial state. Etc. apply. If necessary, the alignment films 21 and 22 may be subjected to an alignment treatment on the surface (the surface in contact with the liquid crystal layer 20) so that the liquid crystal molecules 2 tilt in a predetermined direction when a voltage is applied. For example, polyimide is subjected to orientation treatment by UV irradiation after being formed by a coating method, and SiO _x is subjected to orientation treatment at the same time as film formation by oblique vapor deposition.

(Transparent substrate)
The transparent substrate 5 is a base for forming the counter electrode 4 and the alignment film 21, and is a base for supporting the liquid crystal layer 20 together with the Si substrate 70. Since the transparent substrate 5 is provided on the light incident side of the liquid crystal light modulator 10, a known transparent substrate material is applied so as to transmit the light. Specific examples include SiO ₂ (silicon oxide, glass), sapphire, polycarbonate (PC), and the like.

(Si substrate)
The Si substrate 70 is a base for forming the drive circuit 7, the pixel electrode 3 and the like, and is a material of the drive circuit 7. Further, it is a base for supporting the liquid crystal layer 20 together with the transparent substrate 5. In the present embodiment, since the transistor 7t is formed of a MOSFET (metal oxide semiconductor field effect transistor), it is preferable that the Si substrate 70 is made of a single crystal silicon substrate, depending on the configuration of the drive circuit 7 and the like. , N-type Si substrate and p-type Si substrate can be applied. The storage capacitor 7c may have a three-layer structure of Si on the surface layer of the Si substrate 70, an insulating film formed thereon, and a poly-Si film.

(Wiring, light shielding film)
The signal line 71, the scanning line 72, and the common electrode line 73 are provided on the Si substrate 70 for inputting to the drive circuit 7 and selecting a pixel, and are formed of a general metal electrode material like the pixel electrode 3. And is formed by a known semiconductor wiring forming method such as etching or damascene method. The light-shielding film 74 is provided in a region where the pixel electrode 3 is not provided in plan view as necessary so that light does not enter the Si substrate 70. Here, in the same layer as the signal line 71, a metal electrode material is used. Has been formed.

(Insulating layer)
The insulating layer 6 is provided on the Si substrate 70 and insulates the wirings 71, 72, 73 and the pixel electrode 3 from each other. Further, the insulating layer 6 is preferably provided so as to fill the space between the pixel electrodes 3 and 3 so as to flatten the lower surface of the liquid crystal layer 20. A known inorganic insulating material provided in a semiconductor element or the like can be applied to the insulating layer 6, and specific examples thereof include an oxide film of SiO ₂ , Al ₂ O _3, or the like, Si ₃ N ₄ , MgF _2, or the like. More than one type of material may be applied.

(Method of manufacturing liquid crystal light modulator)
The liquid crystal light modulator according to the present embodiment can be manufactured by a manufacturing method similar to that of a known LCOS type liquid crystal light modulator, with an additional step of forming irregularities on the surface (lower surface) when forming the counter electrode. it can. The manufacturing method of the liquid crystal light modulator includes a counter substrate process of forming the counter electrode 4 and the upper alignment film 21 on the transparent substrate 5, a driving circuit 7, wirings 71, 72, 73, and the pixel electrode 3 on the Si substrate 70. And the circuit board step of forming the lower alignment film 22 are separately performed, and then the transparent substrate 5 and the Si substrate 70 are superposed so that the alignment films 21 and 22 face each other, and the liquid crystal is interposed therebetween. A cell assembly process of encapsulating materials to form the liquid crystal layer 20 is performed. An example of the details of each step will be described below.

  The counter substrate process will be described with reference to FIG. In this step, the lower side of the liquid crystal light modulator 10 including FIG. 6 will be described as the upper side. A conductive oxide such as ITO is formed on the transparent substrate 5 to be thicker than the thickness of the portion (center between pixels) having the convex portion 4r of the counter electrode 4. A coating of a thermosetting resin is applied on this conductive oxide film (indicated by reference numeral "4" in the figure), and the resin film RM thus formed has a mold (mold) as shown in FIG. 6 (a). By pressing ML, the transfer surface shape of the mold ML is transferred to the surface of the resin film RM. Then, after heating the mold ML while pressing it to cure the resin film RM, the mold ML is released from the resin film RM. As a result, an uneven shape corresponding to the counter electrode 4 is formed on the surface of the resin film RM. A UV curable resin may be applied to the resin film RM and the resin film RM may be cured by UV irradiation instead of heating. Therefore, if a mold ML formed of a material having a high UV transmittance such as quartz is used, or if the UV transmittance of the transparent substrate 5 and the counter electrode (conductive oxide film) 4 is sufficiently high, it is transparent. UV irradiation can be performed from the substrate 5 side.

  As shown in FIGS. 6B and 6C, anisotropic etching is performed on the resin film RM to completely remove the resin film RM, and the conductive oxide film thereunder is partially removed. Remove. As a result, the uneven shape of the surface of the resin film RM before etching is transferred to the surface of the conductive oxide film, and the counter electrode 4 is formed. If necessary, the conductive oxide film may be annealed next or before forming the resin film RM.

  The alignment film 21 is formed on the uneven surface of the counter electrode 4. Depending on the material of the alignment film 21, a method capable of forming a film with a uniform thickness even on an uneven surface is applied. When applying an organic film, a film material is applied onto the counter electrode 4 by, for example, a spin coating method and dried. Then, if necessary, an alignment treatment is performed.

The circuit board process will be described. Here, an n-type Si substrate (n-sub) is applied to the Si substrate 70. First, SiO ₂ outside the region (active region) where the transistor 7t and the storage capacitor 7c of the drive circuit 7 are formed is buried, and then p-type impurity ions are implanted to form a p-well for each pixel. . In the region where the storage capacitor 7c is formed, n-type impurity ions are implanted to form a lower terminal of the storage capacitor 7c on the surface layer, and an insulating film is formed thereon. On the other hand, a gate oxide film is formed in the region where the transistor 7t is formed. Next, the gate of the transistor 7t and the upper terminal of the storage capacitor 7c are formed of a poly-Si film. By implanting n-type impurity ions, n ⁺ diffusion layers are formed as the source and drain of the transistor 7t. In addition, p-type impurity ions are implanted to form ap ⁺ diffusion layer for connecting the p-well to GND.

An interlayer insulating film (insulating layer 6) is formed on the Si substrate 70, and each of the upper and lower terminals of the storage capacitor 7c, the source and drain of the transistor 7t, the gate, and the p ⁺ diffusion layer of the interlayer insulating film is formed. Form a hole on top. A metal electrode material is deposited to fill the holes in the interlayer insulating film, and an interlayer insulating film is deposited to form holes and trenches to fill the metal electrode material. In this way, by repeating the formation and processing of the insulating film and the formation of the metal electrode material, the signal line 71 connected to the source of the transistor 7t, the scanning line 72 connected to the gate, and the lower terminal of the storage capacitor 7c. A common electrode line 73 connected to the above is formed, and a wiring (connection portion) connecting the drain of the transistor 7t and the upper terminal of the storage capacitor 7c is formed. Further, this connecting portion is exposed on the surface of the interlayer insulating film to form a contact portion for connecting the pixel electrode 3. Further, the light shielding film 74 is formed together with the signal line 71 and the like. If necessary, the surface is planarized at the end or in the middle.

  An insulating film is further formed on the interlayer insulating film to the thickness of the pixel electrode 3, and a trench in the shape of the pixel electrode 3 is formed by photolithography and etching to expose the contact portion at the bottom. A film of a metal electrode material is formed on this and the pixel electrode 3 is formed by burying it in a trench. On top of that, the alignment film 22 is formed to have a uniform thickness by a method depending on the material, similarly to the alignment film 21.

  The cell assembly process will be described. As a method of enclosing the liquid crystal material, a method suitable for the liquid crystal material or the like is applied, and in the VA method, a liquid crystal drop fill (ODF) method is generally applied. First, a frame-shaped sealing material (not shown) having a thickness corresponding to the cell thickness d is UV-applied to the periphery of the surface of the Si substrate 70 on which the alignment film 22 is formed (outside the area in which the pixels are two-dimensionally arranged). It is made of a curable resin or the like, and the liquid crystal material is dropped in the frame of the sealing material. In a vacuum, the transparent substrate 5 is attached on the Si substrate 70 with the sealing material and the liquid crystal material (liquid crystal layer 20) sandwiched therebetween, with the alignment film 21 facing downward, and the sealing material is cured and brought into close contact with the liquid crystal. The layer 20 is sealed.

(Operation of liquid crystal light modulator)
The operation of the liquid crystal light modulator according to the present invention will be described with reference to FIG. 7 and appropriately FIG. In the bright display pixels 11 and 13, the pixel electrode 3 has a potential of + or − (+ in FIG. 7), and an electric field E in the vertical direction is generated between the pixel electrode 3 and the counter electrode 4 connected to GND (0 V). Occur. At the same time, as described above with reference to FIG. 34, a weak electric field E _L that spreads outward from the pixel electrode 3 (non-opening portion) and obliquely goes to the counter electrode 4 is also generated. However, in the liquid crystal light modulator 10, since the counter electrode 4 is formed so as to project at the center between the pixels, the leaked electric field E _L in the oblique direction is blocked by the convex portion 4r of the counter electrode 4, and the convex portion 4r is formed. It is difficult to reach the dark display pixel 12 on the other side. Further, since the distance between the counter electrode 4 and the pixel electrode 3 in the non-opening portion is short and the resistance is low due to the convex portion 4r, the convex portion 4r is formed from the pixel electrode 3 of the pixels 11 and 13 to the pixel 12 of potential 0V. The electric field E _IP toward the pixel electrode 3 is trapped to weaken the electric field E _IP .

In this way, the leakage electric fields E _L and E _IP that tilt the liquid crystal molecules 2 of the liquid crystal layer 20 to the opening of the dark display pixel 12 adjacent to (interposed between) the bright display pixels 11 and 13 are generated. Occurrence is suppressed. Therefore, the unintended inclination of the liquid crystal molecules 2 is suppressed in the openings of the pixels 12, and sufficient dark display can be obtained by the polarizers 81 and 82 in the crossed Nicols arrangement (see FIG. 4A).

(Modification of liquid crystal light modulator)
In the liquid crystal light modulator 10 according to the present embodiment, the lower surface of the counter electrode 4 may have unevenness only in the X direction. That is, as shown in FIG. 8, it is possible to apply the counter electrode 4A in which the ridge-shaped convex portion 4r along the Y direction is formed. In the Y direction, since the pixel length p _Y is sufficiently long, even if the counter electrode 4A is flat, it is difficult for the leak electric fields E _L and E _IP to reach the vicinity of the pixel center of the pixel in the dark state. Further, in order to suppress the leakage electric fields E _L and E _IP in the Y direction, it is preferable to design the shape of the pixel electrode 3 so that the gap l _gY in the Y direction becomes wide. According to the counter electrode 4A having a convex portion 4r along such direction, the distance between the pixel electrode 3 counter electrode 4 is not greater biased to a point pixel center, since more small opening height difference h _a The unevenness in the bright display pixels is suppressed, and the manufacturing is easy. Further, the width w _rY of the convex portion 4r in the Y direction may be matched with the X direction (p _X = w _rX = w _rY <p _Y ). That is, as shown in FIG. 9, a ridged roof-shaped recess having an isosceles triangle and an isosceles trapezoid as two inner wall surfaces each having a horizontal concave ridge line along the Y direction at the pixel center is formed on the lower surface. The counter electrode 4B which has it can be applied. By providing such a counter electrode 4B, the leakage electric fields E _L and E _IP are suppressed in both the X and Y directions, and the opening height difference h _a is small, as in the modification shown in FIG. The unevenness in the display pixel is suppressed.

[Liquid crystal display device]
The liquid crystal light modulator 10 according to the first embodiment and its modification of the present invention is used in a liquid crystal display device like a general reflection type liquid crystal light modulator. As shown in FIG. 10, a liquid crystal display device 100 according to an embodiment of the present invention includes a liquid crystal light modulator 10 and a polarizing plate (polarizer) 81 arranged on the upper side of the liquid crystal light modulator 10. Light is emitted from above 81, and an image is also displayed above the polarizing plate 81. It is preferable that the liquid crystal display device 100 further includes a retardation plate 83 between the liquid crystal light modulator 10 and the polarizing plate 81. In addition, a lattice-shaped black matrix may be provided so as to shield the non-opening portions of the pixels of the liquid crystal light modulator 10 (not shown). In the case of a full-color display device, a color filter is provided together with the black matrix (not shown). The color filter and the black matrix may be arranged on the transparent substrate 5 of the liquid crystal light modulator 10, or may be formed on the lower surface of the transparent substrate 5 before forming the counter electrode 4. The light with which the liquid crystal display device 100 is irradiated is selected according to the application, such as external light or laser light.

  The polarizing plate 81 makes natural light incident from the outside enter the liquid crystal light modulator 10 as light of one polarization component (linear polarization in one direction), and at the same time, from the light emitted from the liquid crystal light modulator 10, The polarized light of the direction is transmitted and displayed. In the liquid crystal display device 100, the polarizing plate 81 is arranged with its transmission axis at 90 ° (Y direction) (absorption axis at 0 °), and transmits linearly polarized light in the vibration direction of 90 °.

  The retardation plate 83 is provided to compensate for the retardation of light due to the liquid crystal layer 20, and is a λ / 2 retardation plate (1/2 wavelength plate) or a λ / 4 retardation plate (1/4 wavelength plate). Applied. Due to the optical anisotropy of the liquid crystal molecules, the refractive index of the liquid crystal changes depending on the orientation of the liquid crystal molecules. Specifically, in the liquid crystal layer 20, as shown in FIG. 4A, when the liquid crystal molecules 2 are in the vertical direction, the phase difference δ due to the polarization component is 0, whereas the liquid crystal molecules 2 are tilted. And a phase difference occurs. Here, when the liquid crystal molecules 2 are in the horizontal direction as shown in FIG. 4B, the phase difference δ is λ / 4. In the present embodiment, since the liquid crystal layer 20 is brightly displayed with a phase difference, the phase difference changes depending on the angle and the viewing angle becomes narrow. Therefore, it is preferable that the retardation plate 83 compensates for the retardation due to the liquid crystal layer 20. Here, the retardation plate 83 is a λ / 4 retardation plate and is arranged with the slow axis at 45 °.

(Operation of liquid crystal display device)
The operation of the liquid crystal display device according to this embodiment will be described. First, the operation of the pixel 1 in the dark state (see FIG. 4A) will be described. Natural light incident from above becomes linearly polarized light in the Y direction by the polarizing plate 81, and this linearly polarized light is converted by the retardation plate 83 into counterclockwise circularly polarized light. The circularly polarized light passes through the transparent substrate 5 and the counter electrode 4 and enters the liquid crystal layer 20. Since the liquid crystal molecules 2 are in the vertical direction in the liquid crystal layer 20, the counterclockwise circularly polarized light is transmitted as it is and reaches the pixel electrode 3. The left-handed circularly polarized light becomes right-handed circularly polarized light when reflected by the pixel electrode 3, again passes through the liquid crystal layer 20, and further passes through the counter electrode 4 and the transparent substrate 5 to the retardation plate 83. enter in. Since the retardation plate 83 converts the clockwise circularly polarized light into the linearly polarized light in the X direction, the linearly polarized light is shielded by the polarizing plate 81 and is not emitted.

  Next, the operation of the pixel 1 in the bright state (see FIG. 4B) will be described. Similar to the pixel 1 in the dark state, counterclockwise circularly polarized light enters the liquid crystal layer 20 from above, and the liquid crystal layer 20 converts the counterclockwise circularly polarized light into linearly polarized light in the X direction and transmits the linearly polarized light. The linearly polarized light does not change its state when reflected by the pixel electrode 3, and enters the liquid crystal layer 20 again from below. Then, the liquid crystal layer 20 returns the linearly polarized light in the X direction to the counterclockwise circularly polarized light, and the phase difference plate 83 converts it into the linearly polarized light in the Y direction. Therefore, the linearly polarized light passes through the polarizing plate 81 and is emitted.

  As described above, the liquid crystal display device 100 including the reflection-type liquid crystal light modulator 10 includes the single polarizing plate 81 and allows natural light to enter and extract light from the pixel selected for bright display. Further, the liquid crystal display device 100 can display a wide viewing angle by including the retardation plate 83.

[Holography device]
The liquid crystal display device 100 according to the embodiment of the present invention can be used in a holography device. As shown in FIG. 11, the holography device 200 according to the embodiment of the present invention includes a liquid crystal display device 100, a driving unit 91 that drives the liquid crystal light modulator 10 of the liquid crystal display device 100, and a light to the liquid crystal display device 100. A light source device 92 for irradiating and an output optical system 96 for making the emitted light from the liquid crystal display device 100 into a reproduced image VI are provided. The drive unit 91 includes a power supply that generates an electric field E, and selects the signal line 71 and the scanning line 72 by a signal from the outside. The light source device 92 includes a laser light source 93 and a collimator lens 94, and irradiates the liquid crystal display device 100 with parallel light. The output optical system 96 includes one or a plurality of lens arrays in which lenses and microlenses are two-dimensionally arranged according to the size of the liquid crystal display device 100 and the size of the image VI to be reproduced (two lenses are shown in FIG. 11). .

  In the holography device 200 shown in FIG. 11, the light source device 92 is arranged so that the incident light is incident on the liquid crystal display device 100 with a slight inclination so that the optical paths of the incident light and the emitted light do not coincide with each other. An output optical system 96 is arranged. When light is emitted perpendicularly to the incident surface of the liquid crystal display device 100 (incident angle 0 °), the light source device 92 or the output optical system 96 includes a beam splitter (half mirror) to reflect incident light or emitted light. Let it be configured to.

  As described above, according to the liquid crystal light modulators of the first embodiment of the present invention and the modified examples thereof, since the pixels are miniaturized and the electric field crosstalk is suppressed, black floating is caused in the dark display pixels. It is possible to obtain a liquid crystal display device which is displayed with high contrast without causing a problem. Then, according to the holography device using the high-definition liquid crystal display device, a bright reproduced image can be obtained with a wide viewing angle.

[Second Embodiment: Liquid Crystal Light Modulator]
In the liquid crystal light modulators according to the first embodiment and the modifications thereof, since the entire surface of the counter electrode on the liquid crystal layer side is an inclined surface, when the convex portion of the counter electrode is formed high in order to improve the quality of dark display. , The difference in the distance between the pixel electrode and the counter electrode between the center of the pixel and the peripheral edge of the opening becomes large, the brightness unevenness in the bright display pixel becomes large, and the effective opening is reduced. Therefore, as in the first embodiment, it is possible to prevent the black display of the dark display pixels and suppress the uneven brightness of the bright display pixels. The liquid crystal light modulator according to the second embodiment will be described below. The same elements as those in the first embodiment (see FIGS. 1 to 9) are designated by the same reference numerals, and the description thereof will be omitted.

  As shown in FIG. 12, the liquid crystal light modulator 10A according to the second embodiment of the present invention is the same as the liquid crystal light modulator according to the first embodiment shown in FIGS. 1 and 2 except for the counter electrode (transparent electrode film) 4C. It has the same structure as the modulator 10. Further, the counter electrode 4C has the same structure as the counter electrode 4 of the first embodiment except that the shape of the lower surface is different.

(Counter electrode)
In the counter electrode 4C, the lower surface facing the liquid crystal layer 20 is an uneven surface, and as shown in FIG. 13 with the lower surface facing upward, the isosceles trapezoid of the four sides of the truncated pyramid is the inner wall surface, and the upper bottom surface is the bottom surface. A concave portion is formed for each pixel. Therefore, it has a convex ridge line on the inter-pixel center line (represented by the alternate long and short dash line in FIG. 13) in each of the X direction and the Y direction, while having a horizontal plane including the pixel center. In other words, the unevenness on the lower surface of the counter electrode 4C has, similarly to the first embodiment, ridge-shaped convex portions 4r along the X direction and the Y direction between pixels, and the cross-sectional shape of the convex portion 4r. Is an isosceles triangle with the bottom side facing upward (the transparent substrate 5 side). However, in the present embodiment, the widths w _rX and w _rY of the convex portion 4r are shorter than the pixel lengths p _X and p _Y , respectively (p _X > w _rX , p _Y > w _rY ), and the _widths are also in the X and Y directions. To have the same length (w _rX = w _rY = w _r ).

Also in the present embodiment, the counter electrode 4C is formed so as to project at the center between pixels, so that the leakage of the electric field is suppressed (see FIG. 7). On the other hand, since the convex portion 4r is not formed in the entire pixel and the lower surface of the counter electrode 4C has a horizontal plane in the central portion of the pixel, even if the height h of the convex portion 4r is large, the opening height difference h _a Is small, and unevenness in bright display pixels is suppressed. Particularly preferably, the width w _r of the convex portion 4r is less gap l _g of pixel electrodes _{3,3 (w r ≦ l g)} , i.e., the convex portion 4r are provided only on the non-opening portion, the counter electrode 4C The lower surface is a horizontal surface over the entire opening and the height difference h _a of the opening is 0. According to such a counter electrode 4C, even if the aspect ratio of the convex portion 4r is high, the liquid crystal molecules 2 in the vicinity of the counter electrode 4C in the opening portion do not tilt when there is no electric field. Therefore, the height h of the convex portion 4r can be designed to be large within a range where it is not difficult to form the counter electrode 4C and the alignment film 21. That is, similarly to the first embodiment, it is preferable that the aspect ratio of the convex portion 4r is 1 or less (h ≦ w _r ). Also, when the convex portion 4r is provided span the opening with a width greater than the gap _{l g w r (w r>} l g) , the more it is an aspect ratio less than 1/2 (2h ≦ w _r) It is more preferably ⅓ or less (3 _h ≦ w _r ). The widths w _rX and w _{rY of} the convex portion 4r may be different in the X direction and the Y direction.

(Modification of liquid crystal light modulator)
Also in the liquid crystal light modulator 10A according to the present embodiment, the lower surface of the counter electrode 4C may have unevenness only in the X direction. That is, as shown in FIG. 14, a counter electrode 4D having a ridge-shaped convex portion 4r along the Y direction can be applied. Further, as shown in FIG. 15, a horizontal surface may be provided on the top of the convex portion 4r so that the cross-sectional shape is an isosceles trapezoid. The width of the top portion of the convex portion 4r of the counter electrode 4E is smaller than the width w _r , and the slope of the inclined surface of the convex portion 4r (the lower surface of the counter electrode 4E) is 2 or less (w It is preferably _r− h) or less. The width of the top of the convex portion 4r is preferably smaller than the gap l _g between the pixel electrodes 3 and 3.

As yet another modified example, as shown in FIG. 16, a convex portion 4r ₁ having a high aspect ratio and a narrow width (w _r1X , w _r1Y ) is provided to a convex portion 4r ₂ having a relatively low aspect ratio and extending to the pixel center. It is possible to apply the counter electrode 4F having the two-step structure of the convex portion 4r stacked therein. The convex portion 4r ₁ has a convex ridge line on the center between pixels, and the widths w _r1X and w _r1Y (collectively, width w _r1 ) are smaller than the pixel lengths p _X and p _Y (w _r1X <p _X , w _r1Y <p _Y ), preferably less than or equal to the gap l _g between pixel electrodes 3 and 3 (w _r1 ≦ l _g ), that is, limited to the non-opening portion. Like the protrusion 4r of the counter electrode 4 (see FIG. 5) of the first embodiment, the protrusion 4r ₂ is composed of four side surfaces of a quadrangular pyramid and has a concave vertex at the pixel center. In the counter electrode 4F, the height h of the convex portion 4r can be designed to be large without making the formation of the counter electrode 4F and the alignment film 21 difficult, and the effect of suppressing the electric field leakage is enhanced, and Since the lower surface of the opening has a gentle slope, the liquid crystal molecules 2 in the vicinity of the counter electrode 4F do not tilt when there is no electric field. Therefore, in the counter electrode 4F, the convex portion 4r ₁ preferably has an aspect ratio of 1 or less, and the convex portion 4r ₂ preferably has an aspect ratio of 1/2 or less (lower surface gradient is 1 or less). It is more preferably 1/3 or less (the slope of the lower surface is 2/3 or less).

  The counter electrodes 4C, 4D, 4E, and 4F of the second embodiment and its modifications can be formed by processing a transparent electrode material by nanoimprint lithography and etching, as in the first embodiment.

  The liquid crystal light modulator 10A according to the second embodiment and its modification is used in the liquid crystal display device 100 (see FIG. 10), similarly to the liquid crystal light modulator 10 according to the first embodiment, and further this liquid crystal display device. The 100 can be used in the holography device 200 (see FIG. 11).

  As described above, according to the liquid crystal light modulators of the second embodiment and the modification thereof of the present invention, as in the first embodiment, the miniaturized pixels are provided, and the black floating appears in the dark display pixels. It is possible to obtain a liquid crystal display device in which a high-contrast display is performed without occurrence, and further, an effective aperture ratio is widened, and a bright display pixel has high brightness.

[Third Embodiment: Liquid Crystal Light Modulator]
The liquid crystal light modulators according to the first and second embodiments and their modifications are reflective spatial light modulators, but they may be transmissive spatial light modulators. The liquid crystal light modulator according to the third embodiment will be described below. The same elements as those in the first and second embodiments (see FIGS. 1 to 16) are designated by the same reference numerals, and the description thereof will be omitted.

  As shown in FIG. 17, the liquid crystal light modulator 10B according to the third embodiment of the present invention is provided for each pixel with a liquid crystal layer 20, a counter electrode (transparent electrode film) 4E sandwiching the liquid crystal layer 20 from above and below. The transparent substrate 5B is provided with the pixel electrode 3A, the drive circuit 7 (see FIG. 4) connected to the pixel electrode 3A, and the uppermost transparent substrate 5A. The liquid crystal light modulator 10B further includes alignment films 21 and 22 provided in contact with the upper and lower sides of the liquid crystal layer 20, a signal line 71 extending in the Y direction and a scanning line extending in the X direction on the transparent substrate 5B. 72 and the common electrode line 73A (collectively, the wirings 71, 72, 73A), and the insulating layer 6 that insulates the pixel electrode 3A and the layers 71, 72, 73A from each other. The liquid crystal light modulator 10B according to the present embodiment is a transmissive spatial light modulator that transmits light incident from below and emits it upward, and changes the polarization direction of light in the pixel selected at that time. is there. Therefore, in the liquid crystal light modulator 10B, the pixel electrode 3A is formed of a transparent electrode material so as to transmit light. A transparent substrate 5B is provided instead of the Si substrate 70, and the drive circuit 7 (transistor 7t, storage capacitor 7c) is formed on the transparent substrate 5B. Further, the liquid crystal layer 20 preferably has a thickness d for rotating the light transmitted once (one way) by 90 °.

  The counter electrode 4E has the shape described in the modification of the second embodiment (see FIG. 15). In the present embodiment, the counter electrode 4E is formed by depositing a transparent electrode material in a uniform thickness on the transparent substrate 5A having a film-forming surface having irregularities. Like the counter electrode 4E, the pixel electrode 3A is formed of a conductive oxide and is processed into a desired plan view shape by film formation, photolithography, etching, or the like by a known method. In the present embodiment, the pixel electrode 3A is formed so as to avoid the region where the transistor 7t is formed, and has a rectangular shape in plan view with one corner cut away.

  As the transparent substrate 5A and the lower transparent substrate 5B, a known transparent substrate material is applied similarly to the transparent substrate 5 of the first embodiment. Further, since the transparent substrate 5A has irregularities formed on the surface on the side of the counter electrode 4E as described above, a transparent resin may be applied, or a resin may be laminated on a glass substrate or the like. On the other hand, as the transparent substrate 5B, a material having heat resistance is used for forming the semiconductor material of the driving circuit 7, especially the transistor 7t.

  The transistor 7t is composed of a thin film transistor (TFT), and examples of the semiconductor material of the TFT include oxide semiconductors, amorphous silicon (a-Si), and polycrystalline silicon (poly-Si). For miniaturization, the transistor 7t is preferably formed using an oxide semiconductor or poly-Si exhibiting a relatively high electron mobility. In the liquid crystal light modulator 10B, the transistor 7t is arranged at the corner of the pixel and is configured so that light does not enter this region. The storage capacitor 7c has a laminated structure in which the interlayer insulating film (insulating layer 6) under the pixel electrode 3A is sandwiched by the common electrode line 73A and the pixel electrode 3A formed thereunder. Here, the common electrode line 73A is formed of a transparent electrode material so as not to reduce the aperture ratio of the pixel, but a metal electrode material may be applied depending on the arrangement and the like. The signal line 71 and the scanning line 72 are arranged between pixels (non-opening portion) in a plan view.

(Method of manufacturing liquid crystal light modulator)
The liquid crystal light modulator according to the present embodiment is manufactured by a method similar to that of a known transmissive liquid crystal light modulator, and includes a step of forming unevenness on the surface (lower surface) of the transparent substrate 5A before forming the counter electrode. It can be additionally manufactured. The manufacturing method of the liquid crystal light modulator includes a counter substrate process of forming the counter electrode 4E and the upper alignment film 21 on the transparent substrate 5A, a driving circuit 7, wirings 71, 72, 73A, and a pixel electrode 3A on the transparent substrate 5B. And the circuit board step of forming the lower alignment film 22 are individually performed, and then the transparent substrate 5A and the transparent substrate 5B are superposed so that the alignment films 21 and 22 face each other, and the liquid crystal is interposed therebetween. The cell is completed by encapsulating materials and forming a liquid crystal layer 20. The cell assembling process is the same as in the first embodiment. Hereinafter, an example of the details of the counter substrate process and the circuit substrate process will be described.

  The counter substrate process will be described. In this embodiment, the surface (lower surface) of the transparent substrate 5A is processed to form an uneven shape. The transparent substrate 5A can be formed by processing by nanoimprint lithography and etching, similarly to the formation of the counter electrode 4 of the first embodiment (see FIG. 6). Alternatively, it is also possible to apply a resin material and directly transfer the unevenness with a mold to perform molding. After forming the transparent substrate 5A, a conductive oxide film is formed on the uneven surface to form the counter electrode 4E. Similar to the first embodiment, the alignment film 21 is formed on the counter electrode 4E with a uniform thickness by a method depending on the material.

  The circuit board process will be described. Amorphous Si (a-Si) is formed on the transparent substrate 5B by a CVD method or the like, and the a-Si film is crystallized into poly-Si by annealing at about 600 ° C. The poly-Si film is processed to form the source and drain of the transistor 7t. An insulating film is formed thereon to serve as the gate insulating film of the transistor 7t. A metal electrode material is deposited and processed on the gate insulating film to form the gate of the transistor 7t and the scanning line 72. Further, a transparent electrode material is deposited and processed to form the common electrode line 73A. Impurities are implanted into the poly-Si film of the transistor 7t from above the gate. Next, an interlayer insulating film is formed and a contact hole is formed. A signal electrode 71 is formed by depositing and processing a metal electrode material on the interlayer insulating film. Further, an interlayer insulating film is formed and a contact hole is formed. A transparent electrode material is deposited and processed on the interlayer insulating film to form the pixel electrode 3A. The alignment film 22 is formed thereon.

  The operation of the liquid crystal light modulator 10B according to this embodiment is the same as that of the first embodiment described with reference to FIG. Further, instead of the counter electrode 4E, the counter electrodes 4, 4A to 4D, 4F can be applied.

[Liquid crystal display device]
The liquid crystal light modulator 10B according to the third embodiment of the present invention is used in a liquid crystal display device like a general transmissive liquid crystal light modulator. As shown in FIG. 18, a liquid crystal display device 100A according to an embodiment of the present invention includes a liquid crystal light modulator 10B, a polarizing plate (polarizer) 81 arranged on the upper side of the liquid crystal light modulator 10B, and a lower side. A polarizing plate (polarizer) 82 arranged is provided, and light is irradiated from below the polarizing plate 82 to display an image above the polarizing plate 81. Alternatively, the liquid crystal display device 100A can be illuminated with light from above and display an image below. The liquid crystal display device 100A preferably further includes retardation plates 83 and 84 between the liquid crystal light modulator 10B and the polarizing plates 81 and 82, respectively. Further, a black matrix in a lattice shape may be provided so as to shield the non-opening portions of the pixels of the liquid crystal light modulator 10B (not shown). In the case of a full-color display device, a color filter is provided together with the black matrix (not shown). The color filter and the black matrix are arranged on the display side of the liquid crystal light modulator 10B. The light with which the liquid crystal display device 100A is irradiated is selected according to the application such as external light or laser light.

  The polarizing plates 81 and 82 both have the same structure as the polarizing plate 81 of the liquid crystal display device 100, and are arranged in crossed Nicols in the liquid crystal display device 100A. The polarizing plate 81 on the upper side, that is, on the light emitting side, is arranged with its transmission axis at 90 ° (Y direction) (absorption axis at 0 °) and transmits linearly polarized light in the vibration direction of 90 °. On the other hand, the lower polarizing plate 82 is arranged with its transmission axis at 0 ° (X direction) (absorption axis at 90 °), and transmits linearly polarized light having a vibration direction of 0 °. Both the retardation plates 83 and 84 have the same structure as the retardation plate 83 of the liquid crystal display device 100, and the same λ / 4 retardation plate (1/4 wavelength plate) is applied. The retardation plate 83 has a slow axis of 45 °, and the retardation plate 84 has a slow axis of 135 °.

(Operation of liquid crystal display device)
The operation of the liquid crystal display device according to this embodiment will be described. First, the operation of the pixel 1 in the dark state (see FIG. 4A) will be described. The natural light incident from below becomes linearly polarized light in the X direction by the polarizing plate 82, and this linearly polarized light is converted by the retardation plate 84 into clockwise circularly polarized light. This circularly polarized light passes through the transparent substrate 5B, the pixel electrode 3A, etc. and enters the liquid crystal layer 20. Since the liquid crystal molecules 2 are in the vertical direction in the liquid crystal layer 20, the clockwise circularly polarized light is transmitted as it is, transmitted through the counter electrode 4E and the transparent substrate 5A, and enters the retardation plate 83. Since the retardation plate 83 converts the clockwise circularly polarized light into the linearly polarized light in the X direction, the linearly polarized light is shielded by the polarizing plate 81 and is not emitted.

  Next, the operation of the pixel 1 in the bright state (see FIG. 4B) will be described. Similarly to the pixel 1 in the dark state, clockwise circularly polarized light enters the liquid crystal layer 20 from below, and here, the liquid crystal layer 20 converts the clockwise circularly polarized light into the counterclockwise circularly polarized light and transmits the circularly polarized light. Then, since the phase difference plate 83 converts the counterclockwise circularly polarized light into the linearly polarized light in the Y direction, the linearly polarized light passes through the polarizing plate 81 and is emitted.

  As described above, the liquid crystal display device 100A including the transmissive liquid crystal light modulator 10B includes the two polarizing plates 81 and 82 on both sides, and allows natural light to enter to extract light from the pixel selected for bright display. be able to. Further, the liquid crystal display device 100A can display a wide viewing angle by including the retardation plates 83 and 84. The liquid crystal light modulator 10B is used in the liquid crystal display device 100 (see FIG. 10) as a reflection type liquid crystal light modulator by providing a reflection film on one surface or using the transparent substrate 5B as a reflection substrate. May be done.

[Holography device]
Like the liquid crystal display device 100, the liquid crystal display device 100A according to the embodiment of the present invention can be used in the holography device 200 shown in FIG. In this embodiment, the light source device 92 and the output optical system 96 are arranged to face each other with the liquid crystal display device 100A interposed therebetween.

  In order to confirm the effect of the present invention, the light output characteristics of the samples simulating the liquid crystal light modulators according to the first and second embodiments of the present invention were observed by simulation.

The samples have the same specifications in order from the bottom, Si substrate, SiO ₂ film, Al (pixel electrode) having a film thickness of 100 nm, vertical alignment film, VA liquid crystal (liquid crystal layer), vertical alignment film, ITO film (counter electrode). , A glass substrate. The thickness of the counter electrode (ITO film) was 20 nm at the thinnest part. In addition, as shown on the coordinate plane in FIG. 19, the pixel size (pitch) is 1 μm × 2 μm (p _X = 1 μm, p _Y = 2 μm), and the pixel electrode (represented by a bold frame in the figure) is 0.58 μm. × was 1.58μm (l _g = 0.42μm). The simulation was performed by changing the thickness of the liquid crystal layer and the shape of the counter electrode for each sample. In the simulation, the reflectance of Al (pixel electrode) having a film thickness of 100 nm was regarded as 100% for calculation.

(Example 1)
A sample of the liquid crystal light modulator (see FIG. 1) provided with the counter electrode (w _rX = p _X = 1 μm, w _rY = p _Y = 2 μm) shown in FIG. 5 was observed. As shown in Table 1, the thickness of the liquid crystal layer (thickness at the pixel center, cell thickness d) was set to 1 μm, and the height (height difference) h of the convex portion of the counter electrode was changed from 100 nm to 900 nm in 100 nm steps. Samples (No. 1 to 9), a cell thickness d of 1.5 μm, a height h of the convex portion of the counter electrode was 500 nm (No. 11), a cell thickness d of 2 μm, and a convex portion of the counter electrode. A sample (No. 12) having a height h of 500 nm was set. The ridgeline on the lower surface of the counter electrode is shown by a broken line in FIG.

Further, a sample of the liquid crystal light modulator provided with the counter electrode (w _rX = p _x = 1 μm, w _rY = 0) shown in FIG. 8 was observed. A sample (No. 10) in which the cell thickness d was 1 μm and the height h of the convex portion of the counter electrode was 300 nm was set. Further, a liquid crystal light modulator sample (see FIG. 34) provided with a counter electrode (h = 0, w _r = 0) having a thickness of 20 nm without a convex portion was used as Comparative Examples 1 to 3, and a cell thickness d was 1 μm. It was set to 1.5 μm and 2 μm (Ref. 1, 2, 3).

  As shown in FIG. 19, the potential distribution and the liquid crystal alignment were obtained by using a liquid crystal simulator (LCD Master, manufactured by Shintec Co.) with ON (applied voltage 5V) and OFF (0V) for every two pixels on a diagonal line. Further, the plane distribution of the reflectance when the laser light with the wavelength of 633 nm was incident with the two polarizing plates arranged in the crossed Nicols above the sample interposed was obtained.

  No. 20 and 21 show the potential distribution and the liquid crystal alignment for 3 (h = 300 nm) and Comparative Example 1. In addition, No. 3, No. 22 (a), 22 (b) and 22 (c) are two-dimensional distribution charts of the reflectance of Sample No. 10 and Comparative Example 1. No. 11 and Comparative Example 2, potential distributions and liquid crystal orientations are shown in FIGS. 23 and 24, and reflectance two-dimensional distribution diagrams are shown in FIGS. 25 (a) and 25 (b). In addition, No. 3, No. 10, No. 11, No. FIG. 26 shows the reflectance distributions for No. 12 and Comparative Examples 1 to 3.

  The potential distribution and the liquid crystal orientation are shown in a cross section along the X direction passing through the centers of OFF and ON pixels (Y = 1.0 μm, on the one-dot chain line in FIG. 19), and the counter electrode and the pixel electrode are shown by dotted lines. It is represented by. The equipotential lines of the potential distribution chart are in steps of 0.5 V, and a part of the potential (unit: V) is attached. The reflectance distribution is the distribution on the dashed line.

  No. From 1 to 10 and Comparative Example 1 (h = 0), the convex portion of the reflectance and the contrast ratio at the center (X = 0.5 μm, 1.5 μm) of each pixel of dark display (OFF) and bright display (ON). FIG. 27 shows a graph of the height dependence of the. In addition, the reflectance in the pixel of bright display is also represented by a linear graph.

  In Comparative Example 1 in which the counter electrode was flat, electric field crosstalk occurred in the dark display pixel as shown in FIG. 21, and the dark display pixel did not become sufficiently dark as shown in FIG. 22C. On the other hand, in No. 3 in which the convex portion is formed on the counter electrode. 3 and No. No. 10 is a dark display pixel as shown in FIG. 20, in which electric field crosstalk is suppressed in both oblique and horizontal directions, and the dark display pixel is dark as shown in FIGS. 22 (a) and 22 (b). . Further, as shown in FIG. 26, it is clear that the difference in the reflectance in the dark display pixel depending on the presence or absence of the convex portion of the counter electrode. Further, as shown in FIG. 27, as the height h of the convex portion of the counter electrode was larger, the dark display pixel became darker and approached 0%. On the other hand, the pixels for bright display were also darkened, but the contrast ratio was improved. In addition, No. 3 and No. There was almost no difference between 10 and 10 in the distribution of reflectance in the X direction.

  No. of d = 1.5 μm. 11 and Comparative Example 2 as well. The same tendency as 3 and Comparative Example 1 was confirmed. However, in Comparative Example 2, as shown in FIGS. 24 and 25B, the electric field crosstalk was larger than that in Comparative Example 1, and the dark display pixels were bright. Therefore, the height h of the convex portion of the counter electrode is no. No. 3 or more. 23 and 25 (a), the electric field crosstalk of the dark display pixel was not sufficiently suppressed, and although it was sufficiently darker than Comparative Example 2, No. 11 was used. It did not reach 3. Further, No. of d = 2 μm. In Comparative Example 12 and Comparative Example 3, the electric field crosstalk was further increased, and as shown in FIG. 26, the provision of the convex portion on the counter electrode had a certain effect, but the dark display pixel was not sufficiently darkened.

  Here, as shown in FIG. 3, No. 10, No. 11, No. In No. 12, in the pixel of bright display, the position dependency of the reflectance having the peak at the center (X = 1.5 μm) was larger than in Comparative Examples 1 to 3. This is because the shape of the counter electrode has a gradient such that the thickness of the liquid crystal layer, that is, the optical path length becomes maximum at the center of the pixel. It is presumed that the larger the distance from the center, the larger. Further, in No. 1 having a large cell thickness d 11 and No. In No. 12, even in the dark display pixel, the reflectance was high with the peak at the center (X = 0.5 μm). In addition, Comparative Examples 2 and 3 having the same cell thickness d each showed a flat distribution in which the reflectance was substantially minimum at the center of the pixel. This is because the inclined surface of the convex portion of the counter electrode is steep (45 ° in the XZ plane), so that liquid crystal molecules in the vicinity of the counter electrode are tilted and aligned in a non-electric field state. It is considered that this is because the region close to the concave apex or concave ridgeline of the counter electrode sandwiched from both sides by the inclined surface, that is, the liquid crystal molecules near the pixel center are easily affected. Further, as described above, since the thickness of the liquid crystal layer has a gradient, the optical rotation angle of the reflected light is larger toward the pixel center. No. 11 and No. It is presumed that in No. 12, the electric field crosstalk was not sufficiently suppressed and the liquid crystal molecules were inclined to some extent even at the pixel center due to the leakage electric field. When these are combined, No. 11 and No. It is presumed that No. 12 exhibited the position dependency that the reflectance was higher as it was closer to the pixel center even in the dark display pixel.

(Example 2)
In a liquid crystal light modulator having a counter electrode shown in FIG. 13 (see FIG. 12), the cell thickness d is 1 μm, the height h of the convex portion of the counter electrode is 300 nm, and the width w _r (= w _rX = w _rY ). Samples (Nos. 13, 14, 15) having a thickness of 300 nm, 400 nm, and 600 nm were set (see Table 1). In the same manner as in Example 1, the potential distribution, the liquid crystal orientation, and the planar distribution of reflectance were obtained. No. 28, 29, and 30 show potential distributions and liquid crystal orientations, and FIGS. 31 (a), 31 (b), and 31 (c) show reflectance two-dimensional distributions.

No. 13, 14, 15, No. 3 (w _r = 1μm), and Comparative Example 1 (w _r = 0), the distribution of the reflectance shown in FIG. 32 (a), also, the bright display of the pixel (X = 1.0 to 2.0 [mu] m) FIG. 32B shows the distribution of reflectance at the pixel center (X = 1.5 μm) converted to 1. Further, as in the first embodiment, the width dependence of the convex portion of the reflectance and the contrast ratio at the center (X = 0.5 μm, 1.5 μm) of each pixel of dark display (OFF) and bright display (ON). The graph of is shown in FIG. In addition, the reflectance in the pixel of bright display is also represented by a linear graph.

As shown in FIGS. 28 to 30 and FIG. 20, even if the width w _r of the convex portion of the counter electrode was formed to be small, there was almost no difference in the effect of suppressing the electric field crosstalk. And No. Since each of the pixels 13, 14, and 15 has a thick region of the liquid crystal layer in the center of the pixel, as shown in FIGS. 3, 10 (see FIGS. 22 (a) and 22 (b)). In particular, as shown in FIG. 32 (b), the width of the convex portion of the counter electrode w _r is equal to or smaller than the gap l _{g of the} pixel electrode. In Nos. 13 and 14, the bright region was wider than that in Comparative Example 1. On the other hand, as shown in FIGS. 32A and 33, the narrower the width w _r of the convex portion of the counter electrode is, the higher the reflectance at the center (X = 0.5 μm) in the dark display pixel is, and the contrast is increased. Has dropped. However, No. Nos. 13, 14, and 15 had sufficiently low reflectance at the peripheral edge of the opening, and the entire opening of the pixel was displayed dark. In the liquid crystal layer, the alignment regulating force of the alignment film is weak and the liquid crystal molecules remain upright in areas such as the center of the thickness direction where the distance from the alignment film on the surface of the pixel electrode or counter electrode is large. It is difficult to do so, and it is presumed that the direction tends to change even in a weak electric field. The distance between the pixel electrode and the counter electrode is maximum (= cell thickness d) in the region of the counter electrode where there is no protrusion, and the alignment control is performed from the alignment film on either side of the pixel electrode and the counter electrode at the center in the thickness direction. Hard to be done. However, since the peripheral edge of the opening of the pixel is close to the alignment film on the inclined surface of the convex portion of the counter electrode, the alignment regulating force works sufficiently. Therefore, as the width w _r of the convex portion of the counter electrode is narrower, the region where the alignment control force is weaker is wider at the pixel center, and the number of liquid crystal molecules tilted by the weak leakage electric field from the bright display pixel is increased and the reflectance is increased. It is considered to have become higher.

  Although the respective embodiments for implementing the liquid crystal light modulator, the liquid crystal display device, and the holography device of the present invention have been described above, the present invention is not limited to these embodiments and is shown in the claims. Various changes can be made within the range.

100,100A Liquid crystal display device 10,10A, 10B Liquid crystal light modulator 1 Liquid crystal optical element, pixel 200 Holography device 20 Liquid crystal layer 2 Liquid crystal molecules 21,22 Alignment film 3,3A Pixel electrode 4,4A-4F Counter electrode (transparent electrode) film)
5, 5A transparent substrate 5B transparent substrate 6 insulating layer 70 Si substrate (circuit board)
7 Drive circuit 81,82 Polarizing plate (polarizer)
83,84 Retardation plate

Claims (13)

A transparent substrate, a transparent electrode film, a liquid crystal layer, a pixel electrode provided for each pixel two-dimensionally arranged in the x direction and the y direction, and a circuit board having a drive circuit connected to each of the pixel electrodes, A liquid crystal light modulator including in order from the top,
A protrusion having an inclined surface inclined in the x direction is formed on the lower surface of the transparent electrode film so as to minimize the thickness of the liquid crystal layer at the center between pixels adjacent to each other in the x direction. A liquid crystal light modulator characterized in that. A transparent substrate, a transparent electrode film, a liquid crystal layer, a pixel electrode provided for each pixel two-dimensionally arranged in the x direction and the y direction, and a circuit board having a drive circuit connected to each of the pixel electrodes, A liquid crystal light modulator including in order from the top,
In order to minimize the thickness of the liquid crystal layer between adjacent pixels, the transparent electrode film has a convex portion having an inclined surface on the lower surface, and a concave portion surrounded by the convex portion is formed. A liquid crystal light modulator provided for each pixel.   The liquid crystal light modulator according to claim 1, wherein in the transparent electrode film, a bottom of a concave portion sandwiched by the convex portions on the lower surface is a flat surface horizontal to the xy plane.   The liquid crystal light modulator according to any one of claims 1 to 3, wherein the transparent electrode film has a maximum height difference due to unevenness on the lower surface that is equal to or less than the maximum width of the convex portion.   The liquid crystal light modulator according to any one of claims 1 to 4, wherein the transparent substrate is provided with unevenness on a lower surface corresponding to the unevenness on the lower surface of the transparent electrode film.   The liquid crystal light modulator according to claim 1, wherein an array pitch of the pixels is 4 μm or less in at least the x direction.   7. The liquid crystal light according to claim 1, wherein the transparent electrode film has a maximum value of height difference due to unevenness on the lower surface of 20% or more and 70% or less of the maximum thickness of the liquid crystal layer. Modulator.   The liquid crystal light modulator according to any one of claims 1 to 7, which is of a vertical alignment type. The circuit board includes the drive circuit formed of crystalline silicon,
9. The liquid crystal light modulator according to claim 1, wherein the pixel electrode is made of a metal electrode material. The circuit board includes a transparent substrate, and the drive circuit formed of a thin film transistor on the substrate,
9. The liquid crystal light modulator according to claim 1, wherein the pixel electrode is made of a transparent electrode material.   The liquid crystal light modulator according to any one of claims 1 to 10, and a polarizer disposed above the liquid crystal light modulator, the light is irradiated from above, and an image is displayed above. Liquid crystal display device that displays.   The liquid crystal light modulator according to claim 10, and two polarizers arranged on the upper side and the lower side of the liquid crystal light modulator, the light being irradiated from one of the upper side and the lower side, and the image on the other side. Liquid crystal display device that displays.   A liquid crystal display device according to claim 11 or 12, a light source for irradiating the liquid crystal display device with light, and a power supply connected to a drive circuit and a counter electrode of a liquid crystal light modulator of the liquid crystal display device. Holographic device.