JP2007121328A - Liquid crystal panel, and projector using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To materialize a liquid crystal panel in which the problems associated with the disturbances and the variations of the polarization state of linearly polarized light, in passing through an optical path between linear polarization with a polarizing element and until the incidence on a liquid crystal layer are fundamentally dissolved. <P>SOLUTION: In the liquid crystal panel in which a polarization plane of light passing through the liquid crystal layer is rotated, by interposing the liquid crystal layer 10 between mutually opposing substrates 12, 14 and by applying an electric field to the liquid crystal layer 10, the polarizing element 12A, having the function of transmitting only a specified polarized light, is disposed on the liquid crystal layer side of the opposing substrate 12 of the light incident side of the mutually facing substrates interposing the liquid crystal layer 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystal panel and a projector using the same.

  Liquid crystal panels are widely used in various image display devices such as projectors, “light control devices that turn light on and off”, and the like. The liquid crystal panel used for these is generally “a liquid crystal layer is sandwiched between opposing substrates such as a glass plate, and an electric field is applied to the liquid crystal layer by a transparent electrode formed on the surface of the opposing substrate in contact with the liquid crystal layer. The polarization plane of the transmitted light is rotated.

  Therefore, the light incident on the liquid crystal panel is linearly polarized by the polarizing element, the polarization plane is rotated by 90 degrees while passing through the liquid crystal layer, and the light that has been rotated or not rotated is detected on the exit side. If the light is extracted through the optical element, “light whose intensity of incident light is modulated” can be obtained.

  In a liquid crystal panel used for a projector or the like, the “function to rotate the polarization plane of transmitted light” of the liquid crystal layer is subdivided, and each subdivided portion is used as a “pixel” for displaying a part of a display image. The The display image is displayed as “an aggregate state of light modulation by each pixel”. In such a liquid crystal panel, the subdivision of “the function of rotating the polarization plane of transmitted light” is based on driving elements and storage capacitors such as thin film transistors provided so that an electric field is applied to each pixel portion independently. The circuit components such as wiring are used, and these circuit components, transparent electrodes, and the like are formed on the counter substrate.

  The circuit components are formed in a two-dimensional lattice shape (lattice shape), but this portion does not transmit light. Therefore, the light-shielding part formed in a lattice shape is called “black matrix”. In addition, there is a designation of “black mask”, but in this specification, a black matrix is used.

  Conventionally, in projectors and light control devices, a polarizing element that linearly polarizes incident light on a liquid crystal layer is provided “away from the liquid crystal layer”. Therefore, incident light on the liquid crystal layer is linearly polarized by the polarizing element. After being converted, the light enters the liquid crystal layer through the counter substrate or the like, and thus the linearly polarized state of polarization is disturbed or changed on the optical path from the linear polarization to the incidence on the liquid crystal layer. There is a problem that affects the display image and the light control, but a countermeasure for this problem has not been known.

  As described above, the black matrix in the liquid crystal panel that displays an image is light-shielding, so that the illumination efficiency is lowered and becomes a “factor that darkens the display image”. As a measure for increasing the illumination efficiency, “for each pixel” Conventionally, a number of devices that use a “microlens array corresponding to a microlens” to collect incident light on a corresponding pixel portion by each microlens have been known. By using the microlens array, the “illumination efficiency” can be effectively increased and a bright image can be displayed. However, as is conventionally known, the contrast of the displayed image does not necessarily increase.

  Further, Patent Documents 1 to 3 disclose that light incident on a black matrix portion is reflected toward a pixel portion by a micromirror lattice to improve illumination efficiency.

JP-A-9-251162 JP-A-5-100222 Japanese Patent No. 3324209

  In view of the above, the present invention eliminates in principle the problem that the linearly polarized state of polarization is disturbed or changed on the optical path from the linear polarization by the polarizing element to the incidence on the liquid crystal layer. The challenge is to realize a liquid crystal panel.

  Another object of the present invention is to realize a liquid crystal panel capable of effectively improving a decrease in illumination efficiency due to the black matrix in the liquid crystal panel for displaying an image and displaying a bright and high-contrast image.

  Another object of the present invention is to realize a projector using these liquid crystal panels.

  The liquid crystal panel according to the present invention is a “liquid crystal panel in which a liquid crystal layer is sandwiched between opposing substrates and an electric field is applied to the liquid crystal layer to rotate a polarization plane of light transmitted through the liquid crystal layer”. It is characterized (claim 1).

  That is, a polarizing element having a function of transmitting only specific polarized light is disposed on the “liquid crystal layer side of the counter substrate on the light incident side” of the counter substrates sandwiching the liquid crystal layer.

  The counter substrate is a pair of transparent substrates when the liquid crystal panel is of a transmissive type, and is made of glass or resin. In this case, if the liquid crystal panel is for image display, a transparent electrode film and a black matrix are arranged on one side of a pair of transparent substrates forming a counter substrate, and a transparent electrode film common to all pixels is arranged on the other side. A light shielding pattern corresponding to the black matrix is formed as necessary. In the case where the liquid crystal panel is simply “one that turns on and off light transmission”, “subdivision into pixels” is unnecessary.

  When the liquid crystal panel is of a reflective type, one of the counter substrates is a transparent substrate and is made of glass or resin. The other of the counter substrates is a “substrate on which a reflective film is formed”, and the material does not need to be a transparent material. Light enters from the transparent substrate side and is reflected by a reflective film formed on the other counter substrate. An electric field is applied to the liquid crystal layer so that the plane of polarization is rotated by 90 degrees while the light reciprocates through the liquid crystal layer. Therefore, in this case, the polarizing element and the analyzing element are shared.

  2. The liquid crystal panel according to claim 1, wherein the “light incident side counter substrate” is a transparent substrate on the incident side when the liquid crystal panel is a transmissive type, and incident light is incident when the liquid crystal panel is a reflective type. This is the transparent substrate on the incoming side.

  The arrangement position of the polarizing element is determined so as to be positioned between the counter substrate and the black matrix / transparent electrode film.

  As described above, in the liquid crystal panel according to the first aspect, the incident light (irradiation light) to the liquid crystal panel passes through the “incident side counter substrate” among the counter substrates sandwiching the liquid crystal layer, and then passes through the polarizing element. The “specific polarization only” enters the liquid crystal layer. Thus, since the incident light passes through the polarizing element “immediately before entering the liquid crystal layer”, there is no “change in polarization state or disorder” before entering the liquid crystal layer.

  The “polarizing element arranged on the liquid crystal layer side of the counter substrate on the light incident side” may be made of either organic or inorganic material, but when formed of an organic material, it is not affected by the heat treatment during panel manufacturing. Thus, it is necessary to devise manufacturing processes and the like.

The polarizing element made of an inorganic material can be a “wire grid type polarizing element” (Claim 2) or a “photonic crystal type polarizing element” (Claim 3).
The “wire grid type polarizing element” is known, for example, from Japanese Patent Application Laid-Open No. 10-153706 and US Pat. No. 6,122,103, and “a conductive surface is formed on a flat surface of a transparent parallel plate made of an inorganic material such as glass. A one-dimensional linear lattice (wire grid) made of a material ", for example, a refractive index n of an interstitial medium (the inorganic material) of the one-dimensional linear lattice and a one-dimensional linear shape made of a conductive material The product of the arrangement pitch of each lattice line of the lattice: d (nm): n · d is configured to be smaller than the use wavelength. Such a polarizer transmits a polarization component parallel to the lattice arrangement direction of the one-dimensional linear lattice and blocks a polarization component parallel to the lattice line.

  In the case of using a wire grid type polarizing element, an incident-side counter substrate can be made of an inorganic material such as glass, and a “one-dimensional linear lattice made of a conductive material” can be formed on the surface of the counter substrate on the liquid crystal layer side.

  The “photonic crystal type polarizing element” is known from Japanese Patent No. 3325825, and for example, a fine concavo-convex structure is formed on a flat surface of a transparent substrate, and a high concavo-convex structure is formed on the fine concavo-convex structure. Several layers of several tens to several hundreds are laminated to form a “laminated structure” in which a layer of a refractive index and a layer of a low refractive index are alternately paired as a pair of “high refractive index layer and low refractive index layer adjacent to each other”, The surface shape is formed such that the uppermost layer of the laminated structure “waves” according to the period of the concavo-convex structure on the surface of the transparent substrate.

  A polarizing element using a photonic crystal can be produced by a “self-cloning method” described later, or can be produced by a “embossing method” described later.

The liquid crystal panel according to any one of claims 1 to 3, wherein the liquid crystal panel has a pixel array subdivided by a black matrix on the liquid crystal layer side of the counter substrate, and is lighter than the black matrix in accordance with the pattern of the black matrix. A micromirror lattice is formed on the incident side, and the micromirror lattice has a reflection surface portion that reflects light incident toward the black matrix toward a predetermined pixel portion ”.
That is, the liquid crystal panel described in claim 4 is a “liquid crystal panel for image display”.

The black matrix is formed in a “two-dimensional lattice (lattice) shape”, and an opening portion of each cell in the lattice is a “pixel” portion.
Since the “micromirror lattice” is formed in a lattice shape “according to the pattern of the black matrix” as described above, each square portion of the micromirror lattice is a pixel portion. Accordingly, each pixel is surrounded by the reflection surface portion of the micromirror lattice.

  The micromirror lattice has “a reflective surface portion that reflects light incident on the black matrix toward a predetermined pixel portion” means that the reflective surface of the micromirror lattice “reflects light incident on the reflective surface portion of the micromirror lattice. It means that the reflective surface portion is formed so as to reflect toward the “pixel (the predetermined pixel) surrounded by the surface portion”.

  The cross-sectional shape of the micromirror lattice in a cross section parallel to the pixel array direction and the light incident direction may be a triangular shape, a trapezoidal shape, a pentagonal shape, or a smooth convex surface with a curvature at the tip on the light incident side. (Claim 5).

  In this case, when the micromirror lattice “the cross-sectional shape in the cross section parallel to the pixel arrangement direction and the light incident direction is a pentagonal shape”, the pentagonal shape “has a roof-shaped slope on the light incident side tip, The part connected to these slopes may be configured to be parallel to the light incident direction.

The micromirror lattice in the liquid crystal panel according to claim 4 or 5 is engraved as a “groove having a concave cross section” on a surface on the liquid crystal layer side of the counter substrate that sandwiches the liquid crystal layer on the light incident side. (Claim 6).
To “engrave” the micromirror lattice, for example, a resist is applied to the surface to be engraved, and a pattern corresponding to the lattice pattern is exposed through a “density distribution mask that controls the amount of light transmission”. The resist pattern can be obtained by development, and etching can be performed using the resist pattern as a mask.

A reflective film may be formed on the surface of the micromirror lattice (concave surface) engraved on the transparent substrate (Claim 7). You may set to "the angle which produces". The concave portion of the micromirror lattice formed on the transparent substrate can be “filled with another material” (claim 8).
The liquid crystal panel according to claim 6, wherein the concave portion of the micromirror lattice formed on the counter substrate can be filled with “another material having a lower refractive index than that of the counter substrate material” (claim 9). Alternatively, in the liquid crystal panel according to 9, the other material filling the concave portion of the micromirror lattice may include “a filler having a skeleton that is the same as the main material component” (claim 10).

  Furthermore, in the liquid crystal panel according to any one of claims 1 to 10, the surface of the polarizing element may be “smoothed with a material different from the liquid crystal panel constituent material” (claim 11).

  A projector of the present invention is a projector using the liquid crystal panel according to any one of claims 1 to 11 (claim 12).

  As described above, in the liquid crystal panel of the present invention, since the incident light is transmitted through the polarizing element immediately before entering the liquid crystal layer, the principle that the polarization state of the incident light with respect to the liquid crystal layer is disturbed or changed is a principle. Can be eliminated. Further, by using a micromirror lattice, it is possible to improve the contrast while improving the light utilization efficiency.

FIG. 1 shows an embodiment of a liquid crystal panel as an explanatory diagram.
The liquid crystal panel of this embodiment is “transmissive” and “image display”.
The liquid crystal layer 10 is sandwiched between a counter substrate 12 on the light incident side and a counter substrate 14 on the light emission side, and light is incident on the counter substrate 12 from above in the figure and is intensity-modulated according to the display image. Then, it is emitted from the counter substrate 14.

  Therefore, both the opposing substrates 12 and 14 are transparent parallel plates, and the polarizing element 12A having a function of transmitting only specific polarized light, the black matrix 12B, and the transparent electrode film 12C made of ITO are provided on the surface of the opposing substrate 12 on the liquid crystal layer 10 side. A transparent electrode film 14A made of ITO is formed on the surface of the counter substrate 14 on the liquid crystal layer 10 side.

  That is, in the liquid crystal panel shown in FIG. 1, the polarization plane of light transmitted through the liquid crystal layer 10 is swung by sandwiching the liquid crystal layer 10 between the counter substrates 12 and 14 and applying an electric field to the liquid crystal layer 10. In the liquid crystal panel, a polarizing element 12A having a function of transmitting only specific polarized light is disposed on the liquid crystal layer side of the counter substrate 12 on the light incident side of the counter substrates 12 and 14 sandwiching the liquid crystal layer 10 (invoice) Item 1).

  The liquid crystal panel of FIG. 1 has a pixel array subdivided by a black matrix 12B, a micromirror lattice 12D is formed in accordance with the pattern of the black matrix 12B, and the micromirror lattice 12D is incident on the black matrix 12B. As described above, the light source has a reflection surface portion that reflects light incident from the incident side toward a predetermined pixel portion.

As described above, the polarizing element 12A may be a well-known wire grid type polarizing element (Claim 2) or a photonic crystal type polarizing element (Claim 3).
FIG. 2 shows two types of “photonic crystals” as explanatory diagrams.
The photonic crystal shown in FIG. 2A is produced by a known “self-cloning method”, and the photonic crystal shown in FIG. 2B is produced by a “embossing method”. .

  The “photonic crystal produced by the self-cloning method” shown in FIG. 2A uses a transparent substrate 20 in which a “rectangular wave-shaped uneven structure” is formed in the horizontal direction of the figure. A “triangular wave-shaped” adjustment layer 21 is formed on the concavo-convex structure of the transparent substrate 20, and a laminated structure in which high refractive index layers and low refractive index layers are alternately laminated on the adjustment layer 21. 22.

  Both the high-refractive index layer and the low-refractive index layer are made of “a material that is transparent to the light used”. A plurality of pairs (several tens of pairs to several hundreds of pairs as described above) are stacked with “a high refractive index layer and a low refractive index layer adjacent to each other” as a pair. A known film forming technique such as sputtering is used for forming each layer. In addition, the uneven pitch (= triangular wave-shaped pitch on the surface of the adjustment layer) and the layer thickness of each layer to be stacked are set to be “smaller than the wavelength of the used light”.

  In the “photonic crystal produced by the embossing method” shown in FIG. 2B, a “triangular wave shape” is formed by embossing as the surface shape of the transparent resin layer 20B formed on the transparent substrate 20A. On the shape, it has a laminated structure 22 in which high refractive index layers and low refractive index layers are alternately laminated. Of course, the pitch of the triangular wave shape and the layer thickness of each layer to be stacked are set to be “smaller than the wavelength of the used light”.

  Both the photonic crystals shown in FIGS. 2A and 2B have the same cross-sectional shape as the “shown shape” in the direction orthogonal to the drawings, and therefore, the surface of the laminated structure 22 is periodic in the horizontal direction of the drawing. It has a triangular wave shape as a direction.

  The photonic crystal as described above has a triangular wave pitch which is the surface shape of the adjustment layer 21 and the transparent resin layer 20B, the refractive index and thickness of the alternately stacked high refractive index layers, and the refractive index of the low refractive index layers. The optical characteristics and optical functions can be adjusted by changing the number of layers and the number of pairs of these layers as parameters, and the layer thicknesses of the high refractive index layer and the low refractive index layer can be adjusted. By making them different, a “photonic crystal functioning as a polarizing element” can be realized.

  That is, when light is incident on such a “photonic crystal functioning as a polarizing element” from above in FIG. 2, the polarization component that vibrates in the horizontal direction in the figure is transmitted and vibrates in a direction orthogonal to the drawing. The polarization component is reflected, and the transmitted light is linearly polarized.

FIG. 4 is a diagram for explaining the “micromirror lattice”.
The state when the liquid crystal panel shown in FIG. 1 is viewed from above in FIG. 1 is as shown in FIG. The micromirror lattice is a liquid crystal layer of the counter substrate 12 as shown in FIG. 4B showing a state in the bb cross section (cross section parallel to the pixel arrangement direction and the light incident direction) in FIG. In the example shown in FIG. 1 and FIG. 4B, the engraved concave shape is “a groove whose cross section is an isosceles triangle shape (FIG. 1 and FIG. In FIG. 4B, it is a “V-shaped groove having an isosceles triangle shape that is pointed upward”. In these V-shaped grooves, as shown in FIG. 4A, V-shaped grooves 12DP and 12DN orthogonal to each other constitute a lattice structure, and each inclined surface of the groove is a “reflecting surface”.

A rectangular portion partitioned by the V-shaped grooves 12DP and 12DN is a “pixel portion”.
As shown in FIG. 4B, the micromirror lattice formed by the V-shaped grooves 12DP and 12DN is formed in accordance with the pattern of the black matrix 12B (claim 4).
As shown in FIG. 4B, when light is incident from the counter substrate 12 side, “light not directed to the black matrix 12B” passes straight through the counter substrate 12 and passes through the polarizing element 12A. The light is polarized and enters the liquid crystal layer 10 through the transparent electrode 12C. Of the light incident on the counter substrate 12, the light directed toward the black matrix 12 </ b> B is reflected by the reflective surface of the micromirror lattice (the slopes of the V-shaped grooves 12 </ b> DP and 12 </ b> DN) and enters toward the “pixel portion surrounded by the reflective surface”. To do.

  In this way, the “light component that is normally shielded by the black matrix” is effectively irradiated to the pixel portion by the micromirror lattice, so that the light use efficiency is increased.

  As described above, the micromirror lattice is formed by being “engraved as a concave groove” on the surface of the counter substrate 12 on the liquid crystal layer 10 side (Claim 6). Is not limited to the triangular shape (V-shaped groove shape) as in the above-described example, but other shapes such as a trapezoid as shown in FIG. The shape can be a "smooth convex surface having a curvature at the tip on the light incident side" as shown in (c-2), or a "pentagonal shape" as shown in (c-3). .

  A side surface of the “groove having a concave cross section” formed on the counter substrate 12 is a reflecting surface. This reflection surface may be a “reflection surface utilizing total reflection”, but is not limited thereto. The case of the “concave shape having a trapezoidal cross section” shown in FIG. 4 (c-1) will be described as an example. The reflective film RF may be formed on the groove surface of the groove having a trapezoidal cross section. Item 7). Moreover, you may fill the recessed part of a groove part with another material SB (Claim 8). The filling with the different material SB may be performed without forming the reflective film RF.

  When the concave cross-sectional shape constituting the micromirror lattice is a pentagonal shape as shown in FIG. 4 (c-3), that is, it has a “roof-shaped slope” at the tip of the light incident side, and these slopes When the continuous portion has a cross-sectional shape parallel to the light incident direction (vertical direction in FIG. 4 (c-3)), by setting the “angle formed by the roof-shaped slope” to an appropriate range, The inventors have newly found through simulation that the brightness and contrast can be effectively improved. Hereinafter, this point will be described.

  In a micromirror lattice having a concave shape having such a pentagonal cross-sectional shape (hereinafter simply referred to as a “pentagonal groove”), as shown in FIG. 5, the groove interval (corresponding to the pixel pitch) of the pentagonal groove MM. ) Is “p” and the groove depth is “h”. Further, the angle formed by the roof-type slope (hereinafter referred to as “vertical angle”) is θ, and the vertical angle: θ and “h / p” are parameters.

As the liquid crystal panel, a 0.5 inch panel, a 0.6 inch panel, and a 0.7 inch panel were assumed.
The 0.5 inch panel has a pixel pitch: p = 9.5 μm, an opening: 7 × 7 μm, and an aperture ratio: 0.54.
The 0.6 inch panel has a pixel pitch: p = 12 μm, an opening: 9 × 9.5 μm, and an aperture ratio: 0.59.
The 0.7-inch panel has a pixel pitch: p = 14 μm, an opening: 11.5 × 11.5 μm, and an aperture ratio: 0.67.

In order to see “brightness characteristics”, “brightness after passing light emitted from one pixel of the liquid crystal panel through a projection lens of F = 1.7” was examined. As a comparison, the case where light is condensed on the pixel portion by a microlens was assumed.
FIG. 5B shows simulation results for a 0.5-inch panel, where the vertical axis represents brightness (light intensity) and the horizontal axis represents apex angle: θ. The brightness in the case of the “microlens condensing method” in which incident light is condensed on the pixel portion by the microlens is 0.93 on the scale of the vertical axis in the figure.

  The following can be understood from FIG. The brightness after passing through one pixel in the liquid crystal panel and dropping the projection lens changes depending on the apex angle: θ and becomes a “convex curve with a peak”, but the parameter: h / p increases. Accordingly, the peak position shifts to the left in the figure, and the peak value also decreases. Such a tendency of “change in brightness due to change in apex angle: θ” is qualitatively the same for both 0.6 inch panels and 0.7 inch panels.

As a result of the same simulation as described above for the 0.6-inch panel and the 0.7-inch panel, the following became clear.
First, in any panel, if parameter: h / p ≦ 1, apex angle: θ is in the range of 20 to 30 degrees, and brightness is superior to “microlens focusing method”. ing.
In any panel, if the parameter: h / p ≦ 1 and the apex angle: θ is in the range of 20 to 30 degrees, the brightness peak is realized when the apex angle: θ is approximately 26 degrees. .

  Therefore, in the case of the micromirror lattice in which the concave shape by the “pentagonal groove” is engraved when focusing on the brightness, “h / p ≦ 1.0” with respect to the parameter: h / p, and the apex angle: θ. On the other hand, if “20 degrees <θ <30 degrees”, it is possible to realize a brighter display image than the microlens array condensing method, and it is understood that the apex angle: θ is extremely good in the vicinity of 26 degrees. . In addition, it should be noted that the above result is valid even if the F number of the projection lens increases.

  In the case of the microlens condensing method, when the brightness immediately after being emitted from the pixel is 1, the brightness after passing through the projection lens is 0.99 with respect to F number: 1.7, F number: 2 0.9 for 0.9, and 0.81 for F number 2.4.

  In the case of a micromirror lattice with a pentagonal groove, the result of FIG. 5B does not change even if the F number exceeds 2.0 and becomes 2.4. Therefore, in comparison with the microlens focusing method, if a projection lens having an F number of 2.4 is used and the display image is considered brighter than the microlens focusing method, the apex angle: θ It can be seen that the upper limit of is allowed up to nearly 40 degrees.

Next, looking at “Contrast of display image”, as is well known, “Contrast of display image by liquid crystal panel (including when displayed on liquid crystal panel and projected on screen)” is the best. This is the case where the “angle distribution of the light intensity and the angle distribution of the intensity of the light emitted from the pixel” of the light incident on the liquid crystal panel are the same.
Note that “the angular distribution of the light intensity of the incident light on the liquid crystal panel” means “the angular distribution before entering the microlens array” when the microlens array is used.

  In a general projector, the “angle distribution of the light intensity of the incident light on the liquid crystal panel” is as shown in FIG. 5 (c-1), and the direction orthogonal to the liquid crystal panel (incident direction) is set to 0. It has an inclination range of about 10 degrees. In (c-1), the “vertical axis” is the light intensity, and the “horizontal axis” is the angle of the incident light.

  (C-2) of FIG. 5 shows “angle distribution of light intensity of light emitted from a pixel” when h / p = 0.6 and θ = 26 degrees. As is clear from the comparison with (c-1), the angular distribution of the intensity of the light emitted from the pixel is substantially equal to “the angular distribution in the incident light to the liquid crystal panel”. It can be seen that a “display image having a very good contrast” can be realized with a liquid crystal panel using a mirror lattice.

  FIG. 5C-3 shows the “angle distribution of the intensity of light emitted from the pixel” in the case of the microlens focusing method. The angular distribution is greatly different from the distribution of (c-1), and the range of the angular distribution is almost doubled by ± 18 degrees with respect to the incident light range of ± 10 degrees, and the contrast of the display image is increased. It is a cause of lowering. In addition, since the angle distribution is large, the amount of light kicked by the projection lens increases, and the projected display image becomes dark.

  The liquid crystal panel of the present invention using a micromirror lattice can realize performance that surpasses the microlens focusing method in both brightness and contrast of a display image.

  Therefore, by using the “liquid crystal panel having a micromirror lattice” of the present invention as a liquid crystal panel in a known projector device, the “brighter and higher contrast” is obtained as compared with the case of using a microlens focusing liquid crystal panel. It is possible to display a “projected image”.

  A specific example of the liquid crystal panel will be described below. Specific examples 1 to 4 are examples for explaining the engraving of the micromirror lattice on the counter substrate.

Example 1
The “micromirror lattice having a V-shaped groove as a concave shape” described with reference to FIGS. 4A and 4B was produced as follows.
Considering that the pixel pitch is 12.0 μm and the width of the black matrix is 2.5 μm and 3.0 μm in the direction perpendicular to each other, the groove widths of the V-shaped grooves are 2.5 μm and 3.0 μm. Accordingly, the size of one pixel is 9.5 μm and 9 μm in the directions orthogonal to each other.

  A parallel plate-like quartz substrate is used as a substrate to be the counter substrate, TGMR-950 resist is applied to the smooth surface to a thickness of 8.56 μm, and “pre-baking at 100 ° C. for 180 seconds” is performed by a hot plate. It was.

This quartz substrate was exposed with a 1/5 stepper using an “exposure mask”.
The “exposure mask” is a negative mask having a pattern drawn according to the pixel arrangement. The exposure mask is exposed at a defocus of +2.0 μm and an irradiation amount of 390 mW × 1.92 seconds (illuminance: 720 mJ). In the portion corresponding to the line width, “exposure in which the exposure amount continuously changes in the line width direction and the maximum exposure intensity is in the center portion of the line width” was realized. The “+ sign” in the defocus amount display means that the focus position of the exposure pattern is “above the resist surface”.

  After the exposure, PEB (post-exposure baking) was performed at 60 ° C. for 25 minutes, and then the resist was hardened by performing “evacuation while irradiating with ultraviolet rays” for 180 seconds with an ultraviolet curing device.

  The ultraviolet curing device irradiates ultraviolet rays having a wavelength shorter than that used for resist exposure and capable of curing the resist. By this operation, the plasma resistance of the resist is improved and it can withstand the processing in the next step.

The hardened quartz substrate was set in an ICP (inductively coupled plasma) dry etching apparatus, and the degree of vacuum: 1.5 × 10 ⁻³ Toor, CHF ₃ : 5.0, CF ₄ : 50, O ₂ : 20 sccm, “Dry etching” was performed at a substrate bias power of 300 W, an upper electrode power of 1.25 kW, and a substrate cooling temperature of −20 ° C. At this time, the substrate bias power and the upper electrode power were changed over time so that the selection ratio increased with time.

  The average etching rate of the quartz substrate was 0.63 μm / min, and the etching time required 18.0 minutes. The “etching depth” after the etching is 11.33 μm. Resist remained at a thickness of about 1.1 μm on the processed surface after etching. Therefore, the average selection ratio of processing is about 1.52.

The “shape formed on the surface of the quartz substrate” by the above method is a groove having a V-shaped cross section (V-shaped groove) formed so as to delimit the smooth surface of the quartz substrate. The portion delimited by the V-shaped groove is a “grid shape”, and the adjacent mesh and the mesh are divided by the V-shaped groove, and each side surface of the V-shaped groove becomes “the slope of the adjacent mesh portion”. ing. That is, when the surface of the quartz substrate on which the V-shaped grooves are engraved is seen, the “quadratic quadrangular pyramids surrounded by the slopes by the side surfaces of the V-shaped grooves” are closely arranged in a two-dimensional manner.
The cross-sectional shape of the V-shaped groove was a tip angle of 10.1 degrees (center line reference: ± 5.05 °).

Next, the quartz substrate with the resist remaining was set in a “self-revolving sputtering apparatus having a cryopump in the exhaust system”, and thin film sputtering was performed.
First, the inside of the sputtering apparatus is evacuated to 0.8 × 10 ⁻³ Pa or lower and exhausted until the partial pressure of H ₂ O becomes 0.1% or lower. In this state, argon: 20 sccm was introduced, reverse bias: 100 W was applied to the quartz substrate, and surface activation by plasma was performed for 3 minutes. Then, argon: 20 sccm was introduced, and an aluminum target was pre-sputtered at a pressure of 3 × 10 ⁻¹ Pa (with the shutter closed), and then the shutter was opened to form an aluminum film for 4 minutes. The formed aluminum film had a thickness of 1000 Å (100 nm) and an average film formation rate of 4.2 Å / sec.

Subsequently, a chromium film was formed. After introducing argon: 20 sccm and pre-sputtering a chromium target (with the shutter closed) at a pressure of 3 × 10 ⁻¹ Pa, the shutter was opened and chromium was deposited for 2.0 minutes. The obtained chromium film had a thickness of 600 mm (60 nm) and an average film forming speed of 5 mm / sec.

  The light reflectance of the two-layer thin film is 90% or more on average in the visible light wavelength. When this state was observed with a cross-sectional SEM, it was found that a uniform aluminum film and a chromium film were formed on the side surfaces of the V-shaped groove and the remaining resist surface with good step coverage.

  Next, the quartz substrate in the above state was immersed in “an organic solvent heated at 60 ° C. (stripping solution)”, and the resist remaining on the substrate was stripped off while being irradiated with ultrasonic waves (lift-off). At this time, the aluminum film and the chromium film on the resist were also peeled off. Furthermore, the substrate after lift-off was washed with an organic solvent. When this state was observed by cross-sectional SEM, it was found that an aluminum film and a chromium film were uniformly formed on the side surface of the V-shaped groove. The aluminum film / chromium film formed on the side surface of the V-shaped groove is a “reflection film” in the micromirror lattice.

Next, glass filler having a particle size of φ200 nm and φ100 nm (SiO ₂ main component system / spherical glass ball beads; particle size: including glass fillers of φ200 nm and φ100 nm in half) and a material main component ratio: 30 % Of a sol-gel material (organic solvent component: about 50%) of a “low viscosity composite material”, a surface on which a V-shaped groove is formed (the reflective film is formed on the side surface of the V-shaped groove). It was applied with a spinner.

  In addition, the sol-gel material illustrated here is only an example. The particle size of the filler varies depending on the depth of the V-shaped groove and the opening width, and the main component ratio and the organic solvent ratio may be changed depending on the viscosity at the time of application. Moreover, a filler may not be included. After application, post-baking at 120 ° C. was performed for 2 minutes.

By repeating this coating / post-baking process three times, the V-shaped groove having a depth of about 11.33 μm could be completely filled. Finally, the sol-gel material was completely cured by baking at 400 ° C. for 30 minutes. The fully cured sol-gel material has its surface covered with “an extremely thin thin film material having SiO ₂ as its main component as a skeleton”. Various materials such as PDMS (polydimethylsiloxane) inorganic / organic hybrid materials can be used for the sol-gel material.

  In this way, a counter substrate on the incident side of the liquid crystal panel is obtained. On this counter substrate, a micromirror lattice is engraved as a groove (V-shaped groove) having a concave cross section, and a reflective film (aluminum film / chrome) is formed on the surface of the micromirror lattice (side surface of the V-shaped groove). Film) and the recesses of the micromirror lattice are filled with another material (the fully cured sol-gel material).

  In this specific example, since the sol-gel material is used to fill the V-shaped groove, the refractive index is not particularly problematic. However, the filler filling rate affects the material shrinkage, the material strength after curing, and the crack generation rate, and the main component molecular structure affects the adhesion, material strength, environmental resistance (humidity resistance) and the like. For this reason, it goes without saying that an optimum material should be selected according to the opening width and depth of the V-shaped groove, the film forming material of the reflective film, and the like.

The surface of the counter substrate formed as described above is completely filled with a sol-gel material, and the fully cured SiO ₂ skeleton sol-gel material covers the surface. As a result of measuring the flatness of the surface in this state, it was found that the Ra had a surface roughness of 0.05 to 0.15 μm.

When used as a counter substrate, the surface roughness is preferably as small as possible, and Ra: 0.10 μm or less is required. Therefore, polishing may be performed on the “surface of the completely cured SiO ₂ skeleton sol-gel material” as necessary.

  In this specific example 1, a sol-gel material containing no filler was finally applied again and baked. As a result of measuring the surface flatness after firing, it was found that the surface roughness Ra was improved to 0.05 μm or less.

Example 2
Specific example 2 is an example of a method of engraving micromirror lattices by a transfer method.

(1) Production of transfer mold
A silicon substrate having a (100) surface cut out from a silicon ingot manufactured by the MCZ method was polished on both sides, and a thermal oxide film was formed to a thickness of 0.5 μm by a normal method. The crystal axis of this silicon substrate was determined using the sacrificial layer method.
A 1.0 μm resist was applied to this silicon substrate in the same manner as in the first specific example and prebaked.

  Next, a pattern was exposed with a stepper while aligning the crystal axis using a reticle designed in advance according to the V-shaped groove opening width corresponding to the black matrix: 3.0 μm and the pitch of the liquid crystal device: 12.0 μm. .

In this exposure, the lattice pattern was exposed with high precision alignment with the silicon crystal axis. Furthermore, the target resist pattern was formed on the silicon substrate by development and rinsing.
Next, the thermal oxide film on the silicon substrate was wet-etched with a light HF solution (hydrofluoric acid 1.5%), and line widths matching the V-shaped groove corresponding to the black matrix: 2.5 μm and 3.0 μm oxide films Only the pattern (thickness: 1.0 μm resist remained on the oxide film) remained and formed in a grid pattern.

  Further, the silicon substrate was wet etched with a solution of KOH solution (concentration: 25%, temperature: 60 ° C.) for 15 minutes. As a result, the silicon under the thermal oxide film was etched into a taper shape. The cross-sectional shape is a top: a convexity shape of 0.1 μm (a shape obtained by vertically inverting the V-shape of Example 1).

Next, the thermal oxide film was completely removed with an HF solution. Through the above steps, the top: a convex mountain shape of 0.1 μm was produced, and a “transfer mold with the V-shape inverted upside down” could be produced.
In this transfer mold, a convex ridge shape having a width of 3.0 μm, a depth of 3 μm, a V-shaped apex angle of 70.6 °, and a top width of 0.1 μm is formed in a grid pattern.

(2) Surface treatment of material substrate to be counter substrate A parallel plate-like quartz substrate is used as the material substrate to be the counter substrate, and a silane cup is attached to the material substrate to increase the adhesion between the material substrate and the resin. Ring treatment was applied.

(3) Cleaning of transfer mold surface The surface of the transfer mold is subjected to “Carros cleaning with a mixed solution of sulfuric acid and H ₂ O ₂ ”, followed by “exciter light irradiation while flowing O ₂ gas to remove O ₃ . An excimer cleaning process is performed to oxidize and remove organic substances on the substrate surface. At this time, a water repellent treatment was performed as necessary.

(4) Resin transfer (4-1) Resin application First, a material substrate is set in a resin discharge device, and 0.3 mg of UV curable resin (GRANDIC RC 8790 (Dainippon Ink Co., Ltd. After applying the product)), the transfer mold was set in the same apparatus, and 0.3 mg of the resin was applied to the portion to be transferred.

(4-2) Surface alignment Next, surface alignment was performed by placing a material substrate on a transfer mold. At this time, care should be taken so that air does not enter the transfer region.

(4-3) Pressurization A pressurizing process was performed using an automatic pressurizing machine so that the transfer mold and the material substrate subjected to surface matching were pressed against each other.

(4-5) Preliminary curing After the pressure treatment, the UV curable resin sandwiched between the transfer mold and the material substrate is irradiated with UV light, giving an energy of about 70% of the energy for complete curing, A temporary curing process was performed to give a certain degree of curing. That is, by exposing a small area of the resin layer from the transfer mold side and “shifting” the exposure position little by little, the pattern shape of the transfer mold (width: 3.0 μm, depth: 3 μm, V-shaped apex angle) : 70.6 °, top width: 0.1 μm convex mountain shape).

(4-6) Curing Resin curing was performed for the purpose of releasing the UV curable resin from the transfer mold and “giving the resin sufficient etching resistance”. The curing process at this time was performed at once in a short time, and the mold was effectively released by drawing the resin (resin shrinkage by curing).

(4-7) Release Next, a set of the transfer mold and the material substrate was set on a release jig with the material substrate side up, and the material substrate was peeled off from the mold. The “fine shape of the transfer mold” was transferred to the ultraviolet curable resin layer on the material substrate, and a “V-groove pattern” was formed as the surface shape of the cured ultraviolet curable resin. The transfer mold after peeling is washed and used repeatedly.

  Through the above steps, a V-groove pattern (corresponding to a micromirror lattice pattern) could be formed in the ultraviolet curable resin layer on the material substrate.

(4-8) Three-dimensional shape after mold release The V-shaped groove pattern formed as described above has a groove width (opening width): 3.0 μm, a depth: 2.8 μm (resin is 0.2 μm by curing) Shrinked), top width: a pattern in which V-shaped grooves of 0.1 μm are formed in a grid pattern.

(5) Dry etching The V-shaped groove pattern formed as the surface shape of the ultraviolet curable resin was transferred to the surface of the material substrate by dry etching.
In the dry etching process, the material substrate is basically set in an ICP (inductively coupled plasma) dry etching apparatus, and the degree of vacuum: 1.5 × 10 ⁻³ Toor, CHF ₃ : 15.0, CF ₄ : 20 sccm, The substrate bias power was 600 W, the upper electrode power was 1.25 KW, and the substrate cooling temperature was −20 ° C. At this time, the substrate bias power and the upper electrode power were changed with time so that the selection ratio increased with time.

Specifically,
(1) The initial stage of etching is: degree of vacuum: 3 × 10 ⁻³ Toor, CHF ₃ : 15.0 sccm, CF ₄ : 10 sccm, substrate bias power: 600 W, upper electrode power: 1.25 KW, substrate cooling temperature: −20 Dry etching was performed under the condition of ° C.

(2) Etching intermediate steps are: degree of vacuum: 1.5 × 10 ⁻³ Toor, CHF ₃ : 15.0 sccm, CF ₄ : 15 sccm, substrate bias power: 550 W, upper electrode power: 1.2 KW, substrate cooling temperature: Dry etching was performed at -20 ° C.

(3) The final stage of etching is: degree of vacuum: 1.5 × 10 ⁻³ Toor, CHF ₃ : 20.0 sccm, CF ₄ : 10 sccm, Ar: 3.0 sccm, substrate bias power: 500 W, upper electrode power: 1. Dry etching was performed under the conditions of 00 KW and substrate cooling temperature: −20 ° C. At this time, as described above, the substrate bias power and the upper electrode power were changed with time so that the selection ratio was “increased with time”.

  The average substrate etching rate in the entire dry etching process was 0.45 μm / min, and an etching time: 23.0 minutes was required. The depth of the V-shaped groove after the etching was 10.5 μm. The ultraviolet curable resin remained with a thickness of about 0.5 μm on the processed surface after the etching. The average selectivity is about 4.56.

  The surface shape of the material substrate (quartz substrate) manufactured in the above process is a checkered pattern of V-shaped grooves having an opening width: 3.0 μm, a depth: 10.5, and a top width: 0 μm. The tip angle of the V-shaped groove was 16.26 ° (center line reference: ± 8.13 °).

Next, the material substrate in the above state was introduced into a self-revolving sputtering apparatus, and thin film sputtering was performed.
First, the back pressure of the sputtering apparatus is exhausted to 1.0 × 10 ⁻³ Pa or less. In this state, argon: 20 sccm was introduced, reverse bias: 100 W was applied to the material substrate, and the surface was activated with plasma for 3 minutes. Next, after introducing argon: 20 sccm and pre-sputtering the chromium target with the shutter closed, under a pressure of 3 × 10 ⁻¹ Pa, the shutter was opened and a chromium film was formed for 5 minutes. A chromium film having a thickness of 1300 mm (130 nm) was obtained. The average film formation rate was 4.3 Å / sec.

  A cross-sectional SEM observation of the material substrate in this state revealed that the chromium film was uniformly formed on the side surface of the V-shaped groove and the resin surface with good step coverage.

Next, the material substrate after the chromium film was formed was immersed in an “organic solvent heated to 60 ° C. (acetone-based stripping solution)”, and the remaining resin on the substrate was stripped by applying ultrasonic waves (lift-off). The chromium thin film on the resin was also peeled off at the same time.
After lift-off, cleaning was performed and cross-sectional SEM observation was performed. As a result, a chromium film was uniformly formed on the side surface of the V-shaped groove, and the portion other than the V-shaped groove pattern was a flat surface.

Next, in a sol-gel material (organic solvent component is about 30%) containing 40% glass filler (SiO ₂ main component system / spherical glass ball beads) having a particle size of φ100 nm and a material main component ratio: 30% The viscosity composite material was applied with a spinner, followed by post-baking at 120 ° C. for 2 minutes. By repeating the above-described coating / post-baking process twice, a V-shaped groove having a depth of about 10 μm could be completely filled.

Further, the sol-gel material was completely cured by baking at 400 ° C. for 30 minutes, and finally “the above sol-gel material containing no filler” was applied and baked at 400 ° C. for 30 minutes to completely cure the sol-gel material. The fully cured sol-gel material was covered with a very thin thin film material having a main component SiO ₂ as a skeleton, and a surface with a high flatness (Ra: 0.05 μm) could be obtained.

  In this way, the micromirror lattice is engraved on the surface of the quartz substrate in accordance with the black matrix as a groove (V-shaped groove) having a concave cross section, and the surface of the micromirror lattice (side surface of the V-shaped groove). A counter substrate was obtained in which a reflective film (chrome film) was formed and the recesses of the micromirror lattice were filled with another material (the fully cured sol-gel material).

Example 3
A V-groove pattern was formed on a parallel plate-like neoceram (refractive index: 1.541) substrate in the same process as in Example 1.

  In the same manner as in Example 1, a resist pattern corresponding to micromirror lattice is formed on the surface of the neo-serum substrate, the surface shape is transferred to the surface of the neo-serum substrate by etching, and heated to 60 ° C. to remove the remaining resist on the surface. The film was immersed in the organic solvent (stripping solution), irradiated with ultrasonic waves to remove the remaining resist, and then washed.

  An “acrylic ultraviolet curable resin (refractive index: 1.43)” was applied to the surface of the neoceram substrate on which the V-shaped groove pattern was formed in two portions with a spinner and cured by UV light irradiation. The neoceram substrate surface after the coating and curing treatment is completely filled with the groove with the resin material. Finally, a “low temperature firing type sol-gel material containing no filler” was applied and fired at 150 ° C. for 10 minutes. The surface flatness after firing was 0.05 μm or less in terms of Ra.

  In this manner, the micromirror lattice is engraved on the surface of the neo-ceram substrate in accordance with the black matrix as a groove having a concave cross section (V-shaped groove), and the concave portion of the micromirror lattice is made of another material (the above acrylic type) The counter substrate filled with the UV curable resin) was obtained.

  In the counter substrate of Example 3, a reflective film is not formed on the side surface of the V-shaped groove, and incident light incident at a small angle due to a difference in refractive index is Bragg reflected.

Example 4
In the same manner as in Example 3, a micromirror lattice was formed as a V-shaped groove pattern on a neo-ceram substrate, and glass fillers having a particle size of φ200 nm and φ100 nm (SiO ₂ main component / spherical glass ball beads. Particle size: φ200 nm A low-viscosity composite material (refractive index: 1.42) of a sol-gel material (organic solvent component is about 50%) containing 20% and a main component ratio of 30%. It was applied with.

Then, post-baking was performed at 120 ° C. for 2 minutes. By repeating the coating / post-baking process three times, the V-shaped groove having a depth of about 11.33 μm could be completely filled.
The sol-gel material was completely cured by baking at 400 ° C. for 30 minutes. The fully cured sol-gel material has a surface covered with an extremely thin thin film material having a main component SiO2 as a skeleton.

  Finally, a sol-gel material containing no filler was applied again and baked. The surface flatness after firing was “Ra of 0.05 μm or less”.

  In the fourth example, similarly to the third example, the reflective film is not formed on the side surface of the V-shaped groove pattern constituting the micromirror lattice, and incident light incident at a small angle is Bragg reflected by the difference in refractive index.

  A polarizing element, a black matrix, and a transparent substrate can be formed on the counter substrate described in connection with Specific Examples 1 to 4 above.

A polarizer made of a photonic crystal was formed on the counter substrate obtained in Example 1 by an embossing method. Please refer to FIG.
In FIG. 3, reference numeral 32 indicates “push mold”.
First, the production of the pressing die 32 will be described.

  The crystal axis orientation of a “0.1 μm silicon (100) substrate with a thermal oxide film” manufactured by MCZ (Magnetic field applied Czochralski) method was measured by X-ray diffraction. A photosensitive material for electron beam (resist) was applied on the silicon substrate to a thickness of 0.2 μm, and prebaked at 110 ° C. for 20 minutes.

  Next, using an electron beam drawing apparatus, patterning of “same line / space shape” arranged at equal intervals with respect to the resist in accordance with the crystal axis of the silicon substrate with the thermal oxide film is performed. Development and rinsing were performed. The period (pitch) of the “line / space shape” formed in the resist is 0.19 μm (190 nm). The line / space relationship is "95/95 nm one-to-one relationship".

  Next, the silicon substrate was post-baked in an oven at 120 ° C. for 30 minutes. After the post-baking, a thermal oxide film having a thickness of 0.1 μm was hydrofluoric acid (with a resist on the thermal oxide film as a mask). HF) was wet-etched, and “a line / space uneven shape arranged at equal intervals with a period of 0.19 μm” was patterned in one direction on the surface of the thermal oxide film.

  Next, using the patterned resist and the thermal oxide film as a mask, the silicon substrate was wet etched at 40 ° C. with a “40 wt% KOH (alkali) solution”. As a result, the (100) plane of the silicon substrate was etched, and “V-shaped by the (111) plane of the V-shaped silicon in both the X-axis and Y-axis directions forming an angle of 54.7 ° with the (100) plane. A trench was formed, and the portion of the silicon substrate covered with the thermal oxide film was side-etched, and the thermal oxide film on the (100) surface of the silicon substrate was naturally removed and did not remain.

  In this way, the (100) surface of the silicon substrate was further etched, and the (111) surface of the silicon substrate with V-shaped grooves was formed on the entire surface of the substrate. That is, a silicon substrate having a surface shape of “triangular wave shape in which the surface height changes periodically in one direction without a flat portion” was obtained. The surface on which the V-shaped groove shape was formed was subjected to water repellent treatment to obtain a “push die” using a silicon substrate. The pressing die 32 in FIG. 3 schematically shows such a pressing die.

  Using the pressing die made of the silicon substrate thus obtained, transfer by the nanoprint method was performed.

An HSQ solution was prepared by dissolving HSQ (hydrogen silsesquioxane) material (HSQ manufactured by Dow Corning Silicone Co., Ltd.) in methyl-isobutyl-ketone (MIBK) as a diluent for HSQ. .
After the adhesion treatment was performed on the “surface on which the micromirror lattice was formed” of the counter substrate produced in Example 1, an HSQ solution as a transfer material was applied with a spinner to form an HSQ layer. Thereafter, the counter substrate on which the HSQ layer was formed was allowed to stand at 50 ° C. for 10 minutes, the diluent was volatilized from the HSQ layer, and the viscosity of the HSQ layer was adjusted to “viscosity capable of nanoimprinting”.

  In FIG. 3A, reference numeral 30 indicates “a counter substrate in which a micromirror lattice is formed on a quartz substrate”, and reference numeral 31 indicates “an HSQ layer adjusted to a viscosity capable of nanoimprinting”.

  Next, the mold surface of the silicon substrate was pressed against the HSQ layer 31 to remove bubbles in the HSQ layer 31, and excess transfer material on the counter substrate 30 was poured out from the outer periphery of the substrate to be removed. Subsequently, the counter substrate 30 and the pressing die 32 sandwiching the HSQ layer 31 are moved into the vacuum chamber, a pressure of about 1 mm Torr to 10 mm Torr is applied, and heated at a temperature of 130 ° C. for 10 minutes, The HSQ layer 31 was cured.

  The counter substrate 30 having the HSQ layer 31 and the pressing die 32 were peeled off. At this time, the HSQ layer 31 cured in a triangular wave shape having a V-shaped groove shape remained on the counter substrate 30 and did not remain on the pressing die 32. Further, due to the shrinkage of the HSQ layer 31 when the HSQ layer 31 is heat-cured, the convex shape of the V-shaped groove shape of the HSQ layer 31 has a period (pitch): 0.19 μm and a wave front angle: V of about 50 degrees. It became the convex shape of the groove shape (FIG. 3C).

A reaction (reactive) bias in which the triangular wave surface of the HSQ layer 31 formed on the counter substrate 30 reacts with “Si and Nb particles released from Si and Nb targets” and oxygen as an introduced gas. A laminated structure 33 was formed by alternately laminating “SiO ₂ layers” and “Nb ₂ O ₃ layers” on the surface of the HSQ layer 31 by sputtering.

More specifically, the SiO ₂ layer and the Nb ₂ O ₃ layer were formed by the process of neutral particle deposition from the target, sputter etching by perpendicular incidence of Ar ions, and reattachment of the deposited particles. For film formation by deposition of neutral particles from the target, the high-frequency power applied to the target was 400 W, and the high-frequency power applied to the counter substrate 30 was 60 W. On the other hand, for sputter etching by vertical incidence of Ar ions, the Ar gas pressure was 1.9 mTorr, and the high-frequency power applied to the counter substrate 30 was 60 W. The period of the V-shaped groove shape on the surface of the counter substrate was 190 nm as described above, and the stacking period in the direction perpendicular to the substrate surface of the stacked structure 33 (the vertical direction in FIG. 5D) was 95 nm.

  Hereinafter, as a more specific example, an example of a photonic crystal structure having “a polarization function for blue light” will be described. In the projector, the light that irradiates the liquid crystal panel includes green light and red light, and “changing the wavelength range” of the polarizing element for these lights can be handled by changing the pitch of the laminated structure and changing the thin film configuration. It is.

A “quartz substrate having a refractive index of 1.47” is used as the counter substrate 30, an HSQ layer 31 having a refractive index of 1.46 is formed thereon, and the triangular wave shape is transferred as described above. A “SiO ₂ layer having a refractive index of 1.4753 and a thickness of 54.9 nm” was formed as a first layer on the triangular wave surface. The first layer is an undercoat layer for “improving adhesion between the HSQ layer and the second and higher layers”.

On the first layer, a “first layer” composed of 38 layers from the second layer to the 39th layer was laminated. The second layer in the first layer is “refractive index: 2.3442, film thickness: 69.11 nm Nb ₂ O ₃ layer”, and the third layer is “refractive index: 1.4753, film thickness. : 109.81 nm SiO ₂ layer ”, and up to 38 layers, even numbered layers are“ refractive index: 2.3442, film thickness: 69.11 nm Nb ₂ O ₃ layer ”, odd numbered layers Is “a SiO ₂ layer having a refractive index of 1.4753 and a film thickness of 109.81 nm”.

That is, in the first layer, from the second layer to the 39th layer, “refractive index: 2.3442, film thickness: 69.11 nm Nb ₂ O ₃ layer” and “refractive index: 1.4753, film Thickness: 109.81 nm SiO ₂ layers ”are alternately stacked.

Next, on the 39th layer, as the 40th layer, “refractive index: 2.3442, film thickness: 69.11 nm Nb ₂ O ₃ layer”, on the 40th layer, the 41st As a layer of “refractive index: 1.4753, film thickness: 54.9 nm SiO ₂ layer”, and as a 42nd layer on the 41st layer, “refractive index: 2.3442, film thickness: 19. A “2 nm Nb ₂ O ₃ layer” and a “43 nm layer“ refractive index: 1.4753, film thickness: 61.0 nm SiO ₂ layer ”were laminated on the 42nd layer.

Further, a “second layer consisting of 20 layers from the 44th layer to the 63rd layer” was laminated on the 43rd layer. The 44th layer in the second layer is “refractive index: 2.3455, film thickness: 38.39 nm Nb ₂ O ₃ layer”, and the 45th layer is “refractive index: 1.4778, film thickness. : 61.0 nm SiO ₂ layer ”. That is, the even-numbered layer in the second hierarchy is “Nb ₂ O ₃ layer with refractive index: 2.3455 and film thickness: 38.39 nm”, and the odd-numbered layer is “refractive index: 1.4778 with film thickness. : 61.0 nm SiO ₂ layer ”. That is, from the 44th layer to the 63rd layer, “refractive index: 2.3455, film thickness: 38.39 nm Nb ₂ O ₃ layer” and “refractive index: 1.4778, film thickness: 61. “0 nm SiO ₂ layers” are alternately stacked.

Next, a “third layer consisting of 18 layers from the 64th layer to the 81st layer” was laminated on the 63rd layer. The 64th layer in the third layer is “refractive index: 2.3480, film thickness: 34.55 nm Nb ₂ O ₃ layer”, and the 65th layer is “refractive index: 1.4793, film thickness. : 54.9 nm SiO ₂ layer ”, the even-numbered layer in the third layer is“ refractive index: 2.3480, film thickness: 34.55 nm Nb ₂ O ₃ layer ”, and the odd-numbered layer is“ Refractive index: 1.4793, film thickness: 54.9 nm SiO ₂ layer ”, which are alternately stacked from the 64th layer to the 81st layer.

Finally, an “Nb ₂ O ₃ layer having a refractive index of 2.3480 and a film thickness of 15.36 nm” was formed as the 82nd layer on the 81st layer. The 82nd layer is “an overcoat layer for protecting the laminated structure laminated on the HSQ layer 31.

The refractive indexes in the SiO ₂ layer and the Nb ₂ O ₃ layer are values with respect to light having a wavelength of 360 nm when the respective films are actually formed.
The laminated structure manufactured in this example can be used as a “polarizing element composed of an inorganic material”. An antireflection film was formed on the back side of the counter substrate 30.

  The polarization separation characteristic of the photonic crystal by the laminated structure 33 manufactured in the above example is that the average transmittance of TM polarized light (polarized component that vibrates in the periodic direction of the triangular wave) in the wavelength range of 420 to 520 nm (blue light): The average transmittance of TE-polarized light was not more than 91% and the contrast was not less than 450%.

  According to such a laminated structure, it was confirmed that the TE mode and TM mode polarization components could be sufficiently separated over the blue light wavelength range from 420 nm to 520 nm.

  The contrast of the TM mode with respect to the TE mode is the “ratio of the transmittance of the polarization component” of the TM mode with respect to the transmittance of the polarization component of the TE mode. It is a scale that represents the degree.

  As described above, the triangular wave shape of the laminated structure repeats the V-groove shape with a period (pitch): 0.19 μm, but one angle of the V-groove structure is about 40 degrees, and therefore its height is about 80 nm (0.08 μm). This height is acceptable for the surface roughness of the counter substrate for liquid crystal. However, it goes without saying that a thin film may be formed on the laminated structure in order to flatten the surface or to have an antireflection function as necessary.

As described above, a chromium film for a black matrix was formed by sputtering on the “polarizing element using a photonic crystal having a laminated structure” formed on the counter substrate.
The inside of the sputtering apparatus was evacuated to 0.8 × 10 ⁻³ Pa or less. In this state, argon: 20 sccm was introduced, a reverse bias of 100 W was applied to the counter substrate, and the surface was activated with plasma for 3 minutes. Next, argon was introduced at 20 sccm, and pre-sputtering was performed on the chromium target with the shutter closed with a pressure of 2 × 10 ⁻¹ Pa, and then the shutter was opened to form a chromium film for 5 minutes. The formed chromium film had a thickness of 900 mm (90 nm) and an average film forming speed of 3.0 mm / sec.

  Subsequently, the chromium film was patterned with high precision alignment with the micromirror lattice formed by the V-shaped groove pattern formed on the counter substrate 30. Specifically, a resist is coated on a chromium film with a 0.8 μm spinner, pre-baked at 90 ° C. for 20 minutes, and then exposed to resist using a “prepared black matrix reticle” by a stepper and developed. A resist pattern corresponding to the black matrix was obtained by rinsing, etching was performed using this resist pattern as a mask, the chromium film outside the mask was removed, and finally the resist pattern was removed to form a black matrix.

An “ITO film as a transparent electrode film” was formed on the black mask by sputtering. The inside of the sputtering apparatus was evacuated to 0.8 × 10 ⁻³ Pa or less. In this state, argon: 10 sccm was introduced, a reverse bias of 100 W was applied to the counter substrate, and the surface was “activated by plasma” for 3 minutes. After introducing oxygen: 30 sccm and pre-sputtering the ITO target at a pressure of 2 × 10 ⁻¹ Pa with the shutter closed, the shutter was opened and ITO was deposited for 10 minutes. The obtained ITO film had a thickness of 1100 mm (110 nm) and an average film formation speed of 4.6 mm / sec.

  In this way, “a counter substrate on which a micromirror lattice was engraved and a polarizing element made of photonic crystal, a black mask, and a transparent electrode film were formed by an embossing method” was obtained.

  Separately, an ITO electrode film is formed on the surface of the quartz substrate to produce a “light-emission-side counter substrate”, and liquid crystal is sandwiched between the pair of counter substrates to seal blue light. A liquid crystal panel could be realized.

  In a polarizing element using a photonic crystal, a liquid crystal panel for red light or a liquid crystal panel for green light is formed in the same manner as in the above-described embodiment by adjusting the material and film thickness of each layer constituting the laminated structure. Needless to say, it can be produced.

It is a figure for demonstrating one Embodiment of a liquid crystal panel. It is a figure for demonstrating the polarizing element by a photonic crystal. It is a figure for demonstrating preparation of the polarizing element by a photonic crystal by a stamping method. It is a figure for demonstrating a micromirror lattice. It is a figure for demonstrating the effect using a micromirror lattice.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Liquid crystal layer 12 Counter substrate 14 Counter substrate 12A Polarizing element 12B Black matrix 12C Transparent electrode film 12D Micromirror lattice

Claims (12)

In a liquid crystal panel in which a liquid crystal layer is sandwiched between opposing substrates and a polarization plane of light transmitted through the liquid crystal layer is rotated by applying an electric field to the liquid crystal layer.
A liquid crystal panel, wherein a polarizing element having a function of transmitting only specific polarized light is disposed on a liquid crystal layer side of a counter substrate on a light incident side of a counter substrate sandwiching a liquid crystal layer. The liquid crystal panel according to claim 1,
A liquid crystal panel, wherein the polarizing element is a wire grid type polarizing element. The liquid crystal panel according to claim 1,
A liquid crystal panel, wherein the polarizing element is a photonic crystal type polarizing element. The liquid crystal panel according to any one of claims 1 to 3,
It has a pixel array subdivided by a black matrix on the liquid crystal layer side of the counter substrate,
According to the pattern of the black matrix, a micromirror lattice is formed on the light incident side from the black matrix,
The liquid crystal panel according to claim 1, wherein the micromirror lattice has a reflection surface portion that reflects light incident toward the black matrix toward a predetermined pixel portion. The liquid crystal panel according to claim 4.
The cross-sectional shape of the micromirror lattice in a cross section parallel to the pixel array direction and the light incident direction is a triangular shape, a trapezoidal shape, a pentagonal shape, or a smooth convex surface with a curvature at the tip of the light incident side. A characteristic LCD panel. The liquid crystal panel according to claim 4 or 5,
A liquid crystal panel in which a micromirror lattice is engraved as a groove having a cross-sectional shape on a surface on the liquid crystal layer side of a counter substrate sandwiching a liquid crystal layer on a light incident side. The liquid crystal panel according to claim 6.
A liquid crystal panel, wherein a reflective film is formed on a surface of a micromirror lattice formed on a counter substrate. The liquid crystal panel according to claim 6 or 7,
A liquid crystal panel characterized in that a concave portion of a micromirror lattice formed on a counter substrate is filled with another material. The liquid crystal panel according to claim 6.
A liquid crystal panel, wherein a concave portion of a micromirror lattice formed on a counter substrate is filled with another material having a lower refractive index than that of the counter substrate material. The liquid crystal panel according to claim 8 or 9,
The liquid crystal panel, wherein the another material filling the concave portion of the micromirror lattice includes a filler having the same skeleton as the main material component. The liquid crystal panel according to any one of claims 1 to 10,
A liquid crystal panel characterized in that the surface of a polarizing element is smoothed with a material different from a liquid crystal panel constituent material.   A projector using the liquid crystal panel according to claim 1.

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