JP2007199241A - Liquid crystal device, method for manufacturing liquid crystal device, and projection display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal device into which polarizing elements are integrated without degrading the optical characteristics of the polarizing elements. <P>SOLUTION: In the liquid crystal device constituted of holding a liquid crystal layer 50 between a pair of substrates 1a, 2a, a metallic film 24 having a striped pattern of a predetermined period is arranged on the liquid crystal layer 50 side of at least one substrate 2a, and the liquid crystal layer side surfaces of individual gratings 25 constituting the striped pattern of the metallic film 24 are constituted in saw teeth shape. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystal device, a method for manufacturing a liquid crystal device, and a projection display device.

  A liquid crystal device is used as a light modulation device in a projection display device such as a projector. As such a liquid crystal device, one having a configuration in which a liquid crystal layer is sandwiched between a pair of opposed substrates is known, and a voltage is applied to the liquid crystal layer inside the pair of substrates. Each electrode is formed. A polarizing plate is disposed outside the pair of substrates (on the side different from the surface facing the liquid crystal layer) so that predetermined polarized light is incident on the liquid crystal layer.

In recent years, since projectors are used in various places for various purposes, a projector that is small in size, easy to carry, and highly portable is desired. Therefore, for example, there is a technique for miniaturizing the projector by providing a wire grid type polarizing element inside the liquid crystal device, that is, on the side of the substrate in contact with the liquid crystal layer (substrate inner surface side) (for example, Patent Document 1). reference).
JP-A-9-160013

  In the technique described in Patent Document 1, an electrode is formed on the inner surface of the substrate, a wire grid type lattice film is formed on the inner surface of the electrode, and the lattice film acts as an alignment film and a polarizing plate. . By the way, in order for such a lattice film to function as an alignment film, it is necessary to impart a pretilt. However, although Patent Document 1 discloses a technique in which a lattice film used as a polarizing plate is applied as an alignment film, the pretilt is not described in detail, and the lattice film is simply arranged on the liquid crystal layer side of the substrate. The pretilt cannot be imparted only by using the above-mentioned method.

  The present invention has been made based on the background as described above, and has an object of providing a liquid crystal device having a configuration that can be reduced in size, and in particular, a member disposed on the liquid crystal layer side of a substrate. An object of the present invention is to provide a liquid crystal device having a high display characteristic by simplifying the structure of FIG. It is another object of the present invention to provide a liquid crystal device in which a polarizing element is integrated in addition to the above object, and in particular, to provide a liquid crystal device having excellent display characteristics without reducing the polarization function. .

  In order to solve the above problems, a liquid crystal device of the present invention is a liquid crystal device in which a liquid crystal layer is sandwiched between a pair of substrates, and at least one of the pair of substrates is disposed on the liquid crystal layer side. A metal film having a striped pattern with a predetermined period is disposed, and the metal film has a sawtooth shape on the liquid crystal layer side surface of each lattice constituting the striped pattern. It is characterized by.

  According to such a liquid crystal device, the metal film having a striped pattern has both a polarization function, an electrode function, and a liquid crystal alignment function. Therefore, it is not necessary to separately provide a polarizing plate, an electrode, and an alignment film, which can contribute to cost reduction and downsizing of the apparatus. Here, the polarization function is expressed by selectively transmitting a polarization component perpendicular to the direction in which the lattice of the striped pattern extends. The electrode function is expressed because it is a metal film. The liquid crystal alignment function is realized by aligning the liquid crystal along the direction in which the lattice of the striped pattern extends, and the liquid crystal molecules can be aligned with a pretilt along the sawtooth shape. . As described above, in the liquid crystal device of the present invention, since the polarization function and the alignment function are realized from the metal film, there is no need to dispose the organic film having the polarization function and / or the alignment function as in the related art, and the liquid crystal It is possible to extend the life of the apparatus. For example, even when high-energy light such as a projector is used as a light source, deterioration hardly occurs. In addition, since it is not necessary to provide a rubbing-treated alignment film, display defects due to dust generation and the like are unlikely to occur.

  In the liquid crystal device of the present invention, the metal film may constitute the striped pattern with a period of 10% to 30% (preferably 10% to 20%) of the wavelength of visible light. By configuring the striped pattern with such a period, the polarization characteristic can be suitably expressed. When the period of the striped pattern is less than 10%, it takes time to manufacture and may lead to a decrease in transmittance. On the other hand, when the striped pattern exceeds 30%, the polarization function may be decreased. In addition, about 30% of the wavelength of visible light is convenient and preferable for manufacturing. If the labor for manufacturing is omitted, about 10% to 20% is preferable for securing the polarization function.

  The surface of the lattice on the liquid crystal layer side may have sawtooth-shaped convex portions that are periodically formed along the longitudinal direction thereof. Specifically, the convex portion may be configured to have a first inclined surface and a second inclined surface having different inclination angles. More specifically, the first inclined surface and the second inclined surface may have different areas, for example, the first inclined surface may have a relatively large area. In this case, the pretilt of the liquid crystal molecules is defined along the inclined surface having a small inclination angle. Specifically, the inclination angle of the first inclined surface is preferably about 1 ° to 20 °, and the inclination angle of the second inclined surface is preferably about 70 ° to 90 °. If the convex portions are formed with a period larger than the period of the striped pattern of the grating, it is possible to reliably exhibit excellent polarization characteristics.

  Further, the metal film may be configured such that the respective grids are electrically connected within at least one pixel. Thus, by electrically connecting each grid within one pixel, an electrode function can be suitably realized. Specifically, it is possible to employ a plate-like metal film in which a large number of slit-like spaces are formed, and a plurality of striped patterns formed through these spaces have their end portions. Each pattern is electrically connected by a metal frame member.

  In addition, the metal film is disposed on the counter substrate side where the switching element is not disposed in the pair of substrates, and the lattices are electrically connected in the surface of the counter substrate. Can do. Thus, by electrically connecting the respective grids within the surface of the counter substrate, the electrode function can be suitably realized.

  In addition, a protective film is formed on the liquid crystal layer side of the metal film to cover the lattices and gaps (spaces) formed between the lattices. It can be formed along the shape. By forming such a protective film, liquid crystal can be prevented from entering the lattice. As a result, it is possible to form a space between the gratings with a vacuum or an air layer, preventing a material having a refractive index of 1 or more from interposing between the gratings, and thus high optical characteristics (transmission) as a polarizing element. It is possible to provide a liquid crystal device including a metal film having a ratio, contrast, and the like.

  Next, in order to solve the above-described problem, a method for manufacturing a liquid crystal device according to the present invention includes a step of forming a solid metal film on a substrate, a step of forming a resist on the formed metal film, and the resist Performing a first two-beam interference exposure on the substrate to give a striped first exposure pattern with a predetermined period, and a substrate including the metal film and the resist, with the normal of the substrate as an axis A step of rotating 90 degrees, a step of performing a second two-beam interference exposure on the resist after the rotation, and providing a striped second exposure pattern in a direction intersecting with the first exposure pattern; A step of developing the exposed resist, and a step of transferring the shape of the resist to the metal film by performing dry etching using the developed resist as a mask. 1 and The second two-beam interference exposure is performed with the same light source. Further, in the first two-beam interference exposure, each light beam is incident on the substrate at the same angle with respect to the normal line of the substrate. On the other hand, in the second two-beam interference exposure, the exposure is performed such that each light beam is incident on the substrate at a different angle with respect to the normal line of the substrate.

  By such a method, the above-described liquid crystal device of the present invention can be easily and reliably manufactured. The second two-beam interference exposure can be performed under a condition that the exposure amount is smaller than that of the first two-beam interference exposure. Thereby, in the first and second exposures, the depths of the exposure can be made different, and it is possible to suitably form a striped pattern lattice having a sawtooth shape.

  Moreover, when forming a protective film on the liquid crystal layer side of the metal film, a method of forming a dielectric by anisotropic film formation such as oblique vapor deposition can be employed. By employing anisotropic film formation, a space can be maintained between the lattices, and a metal film having high optical characteristics (transmittance, contrast, etc.) can be provided as a polarizing element.

  On the other hand, the manufacturing method of the liquid crystal device of the present invention may include the following steps as a different mode. That is, a step of forming a solid metal film on the substrate, a step of forming a resist on the formed metal film, a step of transferring the mold shape to the resist by a nanoimprint method using a desired mold, Performing the dry etching using the resist having the transferred shape as a mask, and transferring the shape of the resist to the metal film with respect to the metal film. It can be simply and reliably manufactured.

  Next, in order to solve the above-described problem, a projection display device according to the present invention includes the above-described liquid crystal device as a light modulation device. Specifically, in a projection type display device comprising a light source, a light modulation device that modulates light emitted from the light source, and a projection device that projects light modulated by the light modulation device, the light modulation device Can be configured by the liquid crystal device.

  According to the projection type display device of the present invention, a liquid crystal device in which a polarizing element, an electrode, and a metal film functioning as an alignment film are integrally provided on at least one of the substrates is provided as a light modulation device. Thus, a member for holding the polarizing plate becomes unnecessary, and thus the projection display device can be made thin and small.

  Hereinafter, embodiments of a liquid crystal device and a projection display device of the present invention will be described with reference to the drawings. In each of the following drawings, the scale of each layer and each member is different in order to make each layer and each member recognizable on the drawing.

[First Embodiment]
In the first embodiment, an active matrix liquid crystal device including a thin film transistor (TFT) as a pixel switching element will be described as an example. This liquid crystal device can be suitably used as, for example, a light valve (light modulation device) of a projection display device.

  First, an embodiment of the liquid crystal device of the present invention will be described. FIG. 1 is a plan view showing a schematic configuration of a liquid crystal device, and reference numeral 100 in the drawing denotes a liquid crystal device. FIG. 2 is a diagram showing equivalent circuits such as various elements and wirings in a plurality of pixels formed in a matrix in the image display region of the liquid crystal device 100. FIG. 3 is a diagram showing a schematic configuration of a side cross section of the liquid crystal device 100. As shown in FIG. 1, the liquid crystal device 100 is a region in which a TFT array substrate (first substrate) 1 a and a counter substrate (second substrate) 2 a are bonded together by a sealing material 52 and partitioned by the sealing material 52. A liquid crystal layer 50 is sealed inside.

  A light-shielding film (peripheral parting) 53 made of a light-shielding material is formed in a region inside the region where the sealing material 52 is formed. A data line driving circuit 201 and an external circuit mounting terminal 202 are formed along one side of the TFT array substrate 1a in a region outside the sealing material 52, and a scanning line driving circuit is formed along two sides adjacent to the one side. 204 is formed. On the remaining side of the TFT array substrate 1a, a plurality of wirings 205 for connecting the scanning line driving circuits 204 provided on both sides of the image display area are provided. In addition, an inter-substrate conductive material 206 for providing electrical continuity between the TFT array substrate 1a and the counter substrate 2a is disposed at the corner of the counter substrate 2a.

  Instead of forming the data line driving circuit 201 and the scanning line driving circuit 204 on the TFT array substrate 1a, for example, a TAB (Tape Automated Bonding) substrate on which a driving LSI is mounted and a peripheral portion of the TFT array substrate 1a The terminal group formed in the above may be electrically and mechanically connected via an anisotropic conductive film.

  In the image display area of the liquid crystal device 100 having such a structure, as shown in FIG. 2, a plurality of dots 100a are arranged in a matrix, and each of these dots 100a is used for pixel switching. A TFT 30 is formed, and a data line 6 a for supplying pixel signals S 1, S 2,..., Sn is electrically connected to the source of the TFT 30. Pixel signals S1, S2,..., Sn to be written to the data lines 6a may be supplied line-sequentially in this order, or may be supplied for each group to a plurality of adjacent data lines 6a. .

  Further, the scanning line 3a is electrically connected to the gate of the TFT 30, and the scanning signals G1, G2,..., Gm are applied to the scanning line 3a in a pulse-sequential manner in this order at a predetermined timing. It is configured. The pixel electrode 9 is electrically connected to the drain of the TFT 30, and the pixel signal S1, S2,..., Sn supplied from the data line 6a is obtained by turning on the TFT 30 as a switching element for a certain period. Write to each pixel at a predetermined timing. The pixel signals S1, S2,..., Sn written in the liquid crystal through the pixel electrode 9 in this way are in a certain period between the counter electrode (common electrode) 21 of the counter substrate 2a shown in FIG. Retained. Further, in order to prevent the held pixel signals S1, S2,..., Sn from leaking, a storage capacitor 60 is added in parallel with the liquid crystal capacitor formed between the pixel electrode 9 and the counter electrode 21. Reference numeral 3 b denotes a capacity line constituting the storage capacity 60.

  As shown in FIG. 3, the liquid crystal device 100 has a basic structure in which a liquid crystal layer 50 is sandwiched between a TFT array substrate 1a and a counter substrate 2a made of transparent glass and the like that are opposed to each other vertically. As the liquid crystal mode in the liquid crystal layer 50, a TN (Twisted Nematic) mode is adopted, but an STN (Super Twisted Nematic) mode, an ECB (Electrically Controlled Birefringence) mode, and the like can also be adopted.

  The TFT array substrate 1a is formed on a translucent quartz substrate 10, a pixel electrode 9 made of a transparent conductive film such as TFT 30 and ITO formed on the inner surface side of the quartz substrate 10, and an inner surface side of the pixel electrode 9. And an alignment film 45. In practice, wiring lines such as the data line 6a and the scanning line 3a are formed, but these are not shown in FIG.

  On the other hand, the counter substrate 2a is configured to include a light-transmitting quartz substrate 20 and a wire grid structure (metal film) 24 provided on the inner surface side of the quartz substrate 20 in the same manner as the TFT array substrate 1a. Yes. In the present embodiment, the counter substrate 2a is not formed with a counter electrode and an alignment film, and the wire grid structure 24 has functions as an electrode, an alignment film, and a polarizing plate. Will be described later.

  A liquid crystal layer 50 is held between the substrates 1a and 2a. In this embodiment, light incident from the counter substrate 2a side is transmitted through the liquid crystal layer 50 and further from the TFT array substrate 1a side. It is injected. As the liquid crystal material constituting the liquid crystal layer 50, any liquid crystal material may be used as long as it can be aligned, such as nematic liquid crystal and smectic liquid crystal. However, in the case of a TN type liquid crystal panel, a material that forms nematic liquid crystal is preferable. For example, phenylcyclohexane derivative liquid crystal, biphenyl derivative liquid crystal, biphenyl cyclohexane derivative liquid crystal, terphenyl derivative liquid crystal, phenyl ether derivative liquid crystal, phenyl ester derivative liquid crystal, bicyclohexane derivative liquid crystal, azomethine derivative liquid crystal, azoxy derivative liquid crystal, pyrimidine derivative liquid crystal, dioxane Examples include derivative liquid crystals and cubane derivative liquid crystals. Furthermore, liquid crystal molecules in which a fluorine-based substituent such as a monofluoro group, a difluoro group, a trifluoro group, a trifluoromethyl group, a trifluoromethoxy group, or a difluoromethoxy group is introduced into these nematic liquid crystal molecules are also included.

  In the liquid crystal device 100 of this embodiment, as described above, the wire grid structure 24 disposed on the liquid crystal layer side of the counter substrate 2a has a polarization function, an electrode function, and an alignment function. Hereinafter, the configuration and function of the wire grid structure 24 will be described. 4 is a perspective view schematically showing the configuration of the wire grid structure 24, FIG. 5 is a plan view schematically showing the configuration of the wire grid structure 24, and FIG. 6 is a schematic diagram of the configuration of the wire grid structure 24. FIG. FIG. 7 is a side view (side view of YZ plane and XZ plane of FIG. 4) in two different directions schematically showing the configuration of a modified example of the wire grid structure 24.

  As shown in FIGS. 4 and 5, the wire grid structure 24 includes a lattice 25 made of a metal material (here, aluminum) formed in a striped pattern having a period T <b> 1 via a predetermined interval (gap) 26. It will be. As a metal material which comprises the grating | lattice 25, it is not limited to aluminum, for example, For example, silver etc. may be sufficient. In the present embodiment, the period T1 is configured with a period of 10% to 30% of the wavelength of visible light (for example, 440 nm), specifically, about 44 nm to 132 nm.

  Further, as shown in FIG. 4, the wire grid structure 24 has a substantially rectangular shape in the XZ sectional direction in the drawing, and has a sawtooth shape in the YZ sectional direction in the drawing. Yes. That is, the wire grid structure 24 is configured such that the surface on the liquid crystal layer side of each lattice 25 constituting the striped pattern has a sawtooth shape. Specifically, as shown in FIG. 4, it is configured to have sawtooth-shaped convex portions 25 a that are periodically formed along the longitudinal direction of the grating 25.

  Here, as shown in FIG. 6, the convex portion 25a having a sawtooth shape is configured to have a first inclined surface 25c and a second inclined surface 25d having different inclination angles. That is, the convex portion 25a has a left-right asymmetric surface shape. Specifically, the first inclined surface 25c and the second inclined surface 25d have different areas, and the first inclined surface 25c has a relatively large area. In this case, the pretilt of the liquid crystal molecules 51 is defined along the inclined surface having a small inclination angle. With such a configuration, the alignment function of the wire grid structure 24 is realized, that is, the liquid crystal molecules 51 are aligned along the direction in which the lattice 25 extends (the Y direction in FIG. 4), and the surface shape of the lattice 25 ( It is possible to give a pretilt to the liquid crystal molecules 51 along the sawtooth shape.

  The inclination angle α of the first inclined surface is about 1 ° to 20 ° (10 ° in this embodiment), and the inclination angle β of the second inclined surface is about 70 ° to 90 ° (80 ° in this embodiment). ). In addition, the convex part 25a is formed with the period T2 larger than the period T1 which the striped pattern of the grating | lattice 25 has. Here, the period T2 is about 100 nm to 300 nm.

  On the other hand, each grid | lattice 25 which comprises the wire grid structure 24 is electrically connected. That is, as shown in FIG. 5, the wire grid structure 24 has a configuration in which a large number of slit-like spaces (gap) 26 are formed in the plate-like metal film. A plurality of striped pattern lattices 25 formed in this manner are electrically connected by metal frame members 27 at their ends. The metal frame member 27 is formed in a rectangular ring shape at the periphery of each grid 25, and the metal frame member 27 functions as a conductive electrode that electrically connects each grid 25. The electrode function of the wire grid structure 24 is realized by such electrical connection between the lattices.

  Next, the polarization function of the wire grid structure 24 will be described. FIG. 15 is a diagram for explaining the action when light passes through the wire grid structure 24. As shown in FIG. 15, in the wire grid structure 24, the refractive index nA of the grating 25 and the refractive index nB of the gap 26 interposed between the gratings 25 are different, so that the polarization of light incident on the wire grid structure 24 is changed. Polarization is selected according to the direction. Specifically, the linearly polarized light X having the polarization axis in the direction perpendicular to the extending direction of the grating 25 is transmitted, and the linearly polarized light Y having the polarization axis in the direction parallel to the extending direction of the grating 25 is reflected. . Therefore, the wire grid structure 24 of the present embodiment has the same effect as the light-reflecting polarizer, that is, transmits the polarization component perpendicular to the grid (TM polarization) and is parallel to the grid (TE polarization). Has the effect of reflecting. Thus, the wire grid structure 24 in this embodiment functions as a light reflection type polarizing element.

As shown in FIG. 7, a protective film 27 made of SiO ₂ or the like can be formed on the surface (liquid crystal layer side) of each lattice 25 of the wire grid structure 24. In this case, since the gap (gap) 26 between the striped lattices 25 is protected by the protective film 27, liquid crystal or the like is prevented or suppressed from entering the gap 26. In this case, the gap 26 is a vacuum layer, but may be an air layer mixed with air, for example. Further, in particular, in order to realize the orientation function of the wire grid structure 24, a protective film 27 is formed along the surface shape of the lattice 25 as shown in FIGS. 7 (a) and 7 (b).

  In the present embodiment, the TFT array substrate 1a side is provided with a polarizing plate separate from the liquid crystal device 100. However, a similar wire grid structure 24 may be formed on the TFT array substrate 1a side. Is possible.

  The liquid crystal device 100 of the present embodiment as described above is suitably used as a light modulation device for a projector as will be described later. Therefore, as described above, the liquid crystal device 100 has a structure in which the wire grid structure 24 that functions as a polarizing element is provided integrally with the counter substrate 2a. Members can be eliminated, and the projector can be miniaturized. Of course, the wire grid structure 24 can also be integrally formed on the TFT array substrate 1a side, and in this case, the projector can be downsized.

  Here, a manufacturing method of the liquid crystal device 100 will be described. However, since the manufacturing method is characterized by the manufacturing method of the counter substrate 2a, a known method is adopted as the manufacturing method of the TFT array substrate 1a, and the TFT array substrate 1a and the counter substrate 2a thus manufactured are sealed. A description will be omitted with respect to the point of manufacturing the liquid crystal device by injecting the liquid crystal and then injecting the liquid crystal, and the manufacturing method of the counter substrate 2a will be described with reference to FIGS. 8 and 10 are explanatory views showing an outline of the two-beam interference exposure method used in this embodiment, and FIGS. 9 and 11 are explanatory views showing these exposure modes. FIG. 12 is a graph showing the relationship between the beam intensity ratio and contrast, and FIG. 13 is a graph showing the intensity distribution of interference fringes for each contrast. Further, FIG. 14 is a perspective view schematically showing a resist shape obtained by performing the two-beam interference exposure method of the present embodiment.

  In producing the counter substrate 2a, first, a quartz substrate 20 is prepared, and a metal film 24a (see FIG. 9) to be a lattice 25 is formed on the quartz substrate 20 by vapor deposition or sputtering. Thereafter, a resist is applied on the formed metal film. At that time, an antireflection film may be formed below the resist.

  Next, the applied resist is exposed. Here, the first exposure of the striped pattern is performed by a two-beam interference exposure method using laser light. Specifically, in order to obtain a rectangular shape in the XZ cross-sectional direction of FIG. 4, exposure is performed so that two light beams are incident at the same angle with respect to the normal line of the substrate 20 as shown in FIG. Yes. That is, exposure is performed so that light from the beam splitter 70 enters the substrate 20 through the mirrors 71 and 72 at the same angle. As a result, as shown in FIG. 9, when a positive resist is used, a place where the interference light intensity is high (exposure portion 61) becomes soluble and is dissolved by development.

  After the first exposure, as shown in FIG. 10, the substrate 20 is rotated 90 degrees about the normal line P of the substrate 20, and the substrate 20 is tilted so that the incident angles of the two light beams are different from each other. Second exposure is then performed. At this time, as shown in FIG. 10, the interference angle is shallower than the first angle and the pitch of the interference fringes is widened. As a result, as shown in FIG. 11, an inclined latent image is formed in the resist, and a pattern of the exposed portion 61 and the unexposed portion 60 is formed.

  During the second exposure, the intensity of one of the light beams is adjusted by the beam intensity adjusting mechanism 73. This is to control the resist pattern and is performed by the following mechanism.

Assuming that the intensity ratio of two beams involved in interference is I (1) and I (2), the interference fringe intensity distribution I (x) is given by the following equation.
I (x) = I (1) + I (2) +2 (I (1) + I (2)) ^1/2 cos (2 px / P) (1) (where x is a position coordinate. The contrast C of the interference fringes is defined by (Imax−Imin) / (Imax + Imin))

On the other hand, the contrast C is expressed as follows from the equation (1).
C = 2 (I (1) · I (2)) ^1/2 / (I (1) + I (2)) = 2 (α) ^1/2 / (1 + α) (2) (α represents the ratio of two beam intensities I (1) / I (2) involved in interference)

  FIG. 12 shows the relationship of equation (2). When the beam intensities are equal (α = 1), the contrast is 1.0, that is, a clear interference fringe is obtained. On the other hand, when the beam intensity ratios are not equal, the difference increases and the contrast decreases. FIG. 13 shows the intensity distribution of the interference fringes for each of cases where the contrast C is 1.0 and 0.5. Therefore, when the intensity of one beam is adjusted, the contrast is lowered, and the pattern of the resist 60 formed after development has a gentle shape as shown in FIG.

  When the two exposures as described above are performed and development is performed, a resist having a pattern shape substantially the same as the pattern shape of the grating 25 as shown in FIG. 4 is formed. Thereafter, dry etching is performed using the obtained resist of a predetermined pattern as a mask, shape transfer is performed on the metal film 24a, and the counter substrate 20 including the wire grid structure 24 as shown in FIG. 4 is obtained.

  Then, as described above, the TFT array substrate 1a prepared separately and the sealing material 52 are bonded together, and liquid crystal is injected from an injection port provided in the sealing material 52 to obtain the liquid crystal device 100 of the present embodiment. Yes.

If necessary, SiO ₂ or the like may be formed on the surface of the wire grid structure 24 as a passivation film in order to suppress a chemical reaction between the liquid crystal and the wire grid structure 24. In that case, SiO ₂ or the like is formed by an anisotropic film formation method such as oblique vapor deposition, so that the vapor deposition material such as SiO ₂ does not enter the gap 26 between the lattices 25, and an air layer or a vacuum is put into the gap 26. A protective film having a layer is formed.

  Further, instead of the above-described two-beam interference exposure method, a stripe having a striped projection is pressed against the resist resin, and a stripe pattern is transferred by a nanoimprint method in which a striped groove pattern corresponding to the projection is transferred. A pattern may be formed.

[Second Embodiment]
Next, a projector as an embodiment of the projection display device of the present invention will be described with reference to the drawings. FIG. 16 is a diagram showing a schematic configuration of the projector according to the present embodiment, and reference numeral 800 in the drawing is a projector. The projector 800 of the present embodiment is a liquid crystal projector using the liquid crystal device 100 described above as a light modulation device.

  In FIG. 16, 810 is a light source, 813 and 814 are dichroic mirrors, 815, 816 and 817 are reflection mirrors, 818 is an incident lens, 819 is a relay lens, 820 is an exit lens, and 822, 823 and 824 are from the liquid crystal device 100. A liquid crystal light modulation device (light modulation device), 825 is a cross dichroic prism, and 826 is a projection lens (projection device). The liquid crystal device 100 includes the wire grid structure 24 as described above, and the wire grid structure 24 functions as a polarizing element. Here, a wire grid polarizing plate is also provided on the TFT array substrate 1a side. The formed one is used. That is, the liquid crystal devices 822, 823, and 824 of the present invention have both the light modulation function and the polarization function of the polarizing element.

  The light source 810 includes a lamp 811 such as a metal halide and a reflector 812 that reflects the light of the lamp. As the light source 810, besides a metal halide, an ultrahigh pressure mercury lamp, a flash mercury lamp, a high pressure mercury lamp, a deep UV lamp, a xenon lamp, a xenon flash lamp, or the like can be used.

  The dichroic mirror 813 transmits red light contained in white light from the light source 810 and reflects blue light and green light. The transmitted red light is reflected by the reflection mirror 817 and is incident on the liquid crystal light modulator 822 for red light. The green light reflected by the dichroic mirror 813 is reflected by the dichroic mirror 814 and is incident on the liquid crystal light modulator 823 for green light. Further, the blue light reflected by the dichroic mirror 813 passes through the dichroic mirror 814. For blue light, in order to prevent light loss due to a long optical path, a light guide means 821 including a relay lens system including an incident lens 818, a relay lens 819, and an exit lens 820 is provided. The blue light is incident on the liquid crystal light modulation device 824 for blue light through the light guide unit 821.

  Next, when the light is incident on the light modulation device, the case where the red light is incident on the red light liquid crystal light modulation device 822 will be described as an example. In addition, about the case where blue light and green light enter into each light modulation device 823,824, since it is the same as that of the case of red, the description is abbreviate | omitted.

  Specifically, the liquid crystal light modulation device 822 for red light has a function as a polarizing element as described above. Therefore, the red light incident on the liquid crystal light modulation device 822 for red light first passes through the wire grid structure 24 provided on the counter substrate 2a and becomes linearly polarized light.

  Further, in the liquid crystal light modulation devices 822 to 824, phase control of linearly polarized light incident through the wire grid structure 24 is performed. That is, it is possible to control the driving of the liquid crystal layer 50 by the voltage applied to the pixel electrode 9 and the counter electrode (here, the wire grid structure 24) and to control the phase of the incident light. The phase-controlled light is incident on the wire grid structure 24 disposed on the light exit side and modulated.

  The light of each color modulated by the liquid crystal light modulators 822 to 824 enters the cross dichroic prism 825. The cross dichroic prism 825 is formed by bonding four right-angle prisms. A dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in an X shape at the interface. Yes. These dielectric multilayer films combine the three color lights to form light representing a color image. The combined light is projected onto the screen 827 by the projection lens (projection device) 826, and the image is enlarged and displayed.

  As described above, the projector 800 according to the present embodiment includes the liquid crystal device 100 including the wire grid structure 24 that functions as a polarizing element, an electrode, and an alignment film on the counter substrate 2a as a light modulation device. Thus, a member for holding the polarizing plate becomes unnecessary. Accordingly, since the number of parts constituting the projector 800 is reduced, the projector 800 is thin and small, and has high polarization characteristics and high reliability.

The top view which shows schematic structure of a liquid crystal device. FIG. 6 shows an equivalent circuit of a liquid crystal device. The figure which shows schematic structure of the side cross section of a liquid crystal device. The perspective view which shows the structure of a wire grid structure typically. The top view which shows the structure of a wire grid structure typically. The side view which shows the structure of a wire grid structure typically. The side view which shows typically the structure of the modification of a wire grid structure. Explanatory drawing which shows the outline of 2 light beam interference exposure method. Explanatory drawing which shows an exposure aspect. Explanatory drawing which shows the outline of 2 light beam interference exposure method. Explanatory drawing which shows an exposure aspect. The graph which shows the relationship between beam intensity ratio and contrast. The graph which shows the intensity distribution of the interference fringe for every contrast. The perspective view which shows typically the resist shape obtained by giving exposure. Explanatory drawing when light permeate | transmits a wire grid structure. FIG. 2 is a diagram illustrating a schematic configuration of a projector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a ... TFT array substrate (1st substrate), 2a ... Opposite substrate (2nd substrate), 24 ... Wire grid structure (metal film), 25 ... Lattice, 50 ... Liquid crystal layer, 100 ... Liquid crystal device

Claims (11)

A liquid crystal device having a liquid crystal layer sandwiched between a pair of substrates,
On the liquid crystal layer side of at least one of the pair of substrates, a metal film having a striped pattern with a predetermined period is disposed,
2. The liquid crystal device according to claim 1, wherein the metal film has a sawtooth shape on the liquid crystal layer side surface of each lattice constituting the striped pattern.   The liquid crystal device according to claim 1, wherein the metal film forms the striped pattern with a period of 10% to 30% of a wavelength of visible light.   3. The liquid crystal device according to claim 1, wherein the surface of the lattice on the liquid crystal layer side has sawtooth-shaped protrusions periodically formed along a longitudinal direction thereof.   The liquid crystal device according to claim 3, wherein the convex portion has a first inclined surface and a second inclined surface, each having a different inclination angle.   5. The liquid crystal device according to claim 3, wherein the convex portions are formed with a period larger than a period of the striped pattern of the lattice.   6. The liquid crystal device according to claim 1, wherein each of the lattices of the metal film is electrically connected in at least one pixel. 7.   The metal film is disposed on a counter substrate side of the pair of substrates where a switching element is not disposed, and the respective grids are electrically connected within the surface of the counter substrate. Item 6. The liquid crystal device according to any one of Items 1 to 5.   A protective film is formed on the liquid crystal layer side of the metal film to cover the lattices and gaps formed between the lattices, and the protective film is formed along the sawtooth shape of the lattices. The liquid crystal device according to claim 1, wherein the liquid crystal device is a liquid crystal device. A method for manufacturing a liquid crystal device according to any one of claims 1 to 8,
Forming a solid metal film on the substrate;
Forming a resist on the formed metal film;
Performing a first two-beam interference exposure on the resist to give a striped first exposure pattern with a predetermined period;
Rotating the substrate provided with the metal film and the resist 90 degrees around the normal line of the substrate;
Performing the second two-beam interference exposure on the resist after the rotation, and providing a striped second exposure pattern in a direction intersecting with the first exposure pattern;
Developing the resist subjected to each exposure,
Carrying out dry etching using the developed resist as a mask to transfer the shape of the resist to the metal film with respect to the metal film,
The first and second two-beam interference exposures are performed with the same light source, and in the first two-beam interference exposure, each light beam is applied to the substrate at the same angle with respect to the normal line of the substrate. In the second two-beam interference exposure, the exposure is performed such that each light beam is incident on the substrate at a different angle with respect to the normal line of the substrate. A method for manufacturing a liquid crystal device.   10. The method of manufacturing a liquid crystal device according to claim 9, wherein the second two-beam interference exposure is performed under a condition that the exposure amount is smaller than that of the first two-beam interference exposure. 9. A projection display device comprising the liquid crystal device according to claim 1 as a light modulation device.

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