JP2005157065A - Optical modulator and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical modulator wherein the thermal deterioration of polarization elements can be prevented, temperature is made uniform and image quality can be enhanced, and to provide a projector. <P>SOLUTION: An optical modulator 421 is provided with a pair of substrates 4211 and 4212 having pixel electrodes 4211C and a common electrode 4212B formed on the surfaces thereof opposed to each other, respectively, and a liquid crystal layer 4213 encapsulated between the substrates 4211 and 4212, and modulates incident luminous flux according to image information. An emission side polarization element 4211E wherein a plurality of protrusion parts 4211E1 made of a conductive material, protruding from the substrate 4211 and extending in an in-plane direction of the substrate 4211 are disposed in parallel in a stripe shape is integrally formed on a luminous flux emission side end surface of the substrate 4211. The common electrode 4212B has a construction nearly equal to that of the emission side polarization element 4211E and functions also as a reflection type polarization element. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light modulation element and a projector.

Conventionally, a light source, a light modulation element that modulates a light beam emitted from the light source according to image information, an incident-side polarizing plate and an emission-side polarizing plate that are disposed on the light beam incident side and the light beam emission side of the light modulation element, A projector including a projection optical device that enlarges and projects an optical image modulated by a light modulation element is known (see, for example, Patent Document 1).
Among these, as the light modulation element, for example, an active matrix drive type light modulation element in which an electro-optic material such as liquid crystal is hermetically sealed between a pair of substrates is generally employed. Specifically, a pair of substrates constituting the light modulation element is disposed on the light emission side, and a drive in which a data line, a scanning line, a switching element, a pixel electrode and the like for applying a driving voltage to the liquid crystal are formed is formed. It is composed of a substrate and a counter substrate which is disposed on the light beam incident side and on which a common electrode, a black matrix and the like are formed.
In such a light modulation element, the data lines and scanning lines formed on the drive substrate, the black matrix formed on the counter substrate, etc. absorb the heat generated by the irradiation of the light flux from the light source. The temperature will rise. For this reason, in the projector described in Patent Document 1, the light modulation element is housed in a holding frame made of a thermally conductive material, and heat generated in the pair of substrates is radiated to the holding frame.
Further, as the incident side polarizing plate and the exit side polarizing plate, an absorption type polarizing plate that transmits a light beam having a predetermined polarization axis and absorbs a light beam having another polarization axis is employed. Such an absorption-type polarizing plate is likely to have a high temperature in order to absorb a part of the light beam emitted from the light source. For this reason, in the projector described in Patent Document 1, the incident-side polarizing plate and the emission-side polarizing plate are connected to the light modulation element so that heat generated in the incident-side polarization plate and the emission-side polarization plate is not transmitted to the light modulation element. Are spaced apart from each other.

However, in the projector described in Patent Document 1, when the incident side polarization plate and the emission side polarization plate are continuously used at a high temperature, the color is lost and the polarization function is gradually lost. In addition, it is necessary to dispose the incident-side polarizing plate and the emitting-side polarizing plate with respect to the light modulation element in consideration of heat transfer, and it is difficult to reduce the size of the projector.
In order to solve the above-described problems, a reflective polarizing element that transmits a light beam having a predetermined polarization axis and reflects a light beam having another polarization axis is used as the polarizing plate. A projector in which a modulation element is integrated has been proposed (see, for example, Patent Document 2).
This reflective polarizing element is composed of a multilayer structure film formed by laminating a number of films formed by stretching a polymer, and is integrally formed on the substrate of the light modulation element. By adopting such a structure, light absorption in the polarizing plate can be reduced and thermal deterioration of the polarizing plate can be avoided. Moreover, it is not necessary to consider heat transfer from the polarizing plate to the light modulation element, and the polarizing plate and the light modulation element can be integrally formed.

JP 2000-89364 A JP-A-11-133414

The projector described in Patent Document 1 employs a configuration in which the light modulation element and the holding frame are connected so as to be able to transfer heat in order to improve the heat dissipation characteristics of the light modulation element. It becomes the structure which mainly hold | maintains an outer peripheral edge part, and a space | gap tends to arise between a holding frame and a light modulation element. For this reason, it is difficult to equalize the temperature in the in-plane direction of the light modulation element, which may cause image quality defects such as uneven color and poor contrast.
Further, the projector described in Patent Document 2 has a configuration that can prevent thermal deterioration of the polarizing plate, but cannot be said to be a configuration that can avoid a temperature increase of the light modulation element. Similar to the projector described in Patent Document 1, even when a configuration in which the light modulation element is held by a holding frame made of a heat conductive material is employed, the same problem as described above may occur. .

  An object of the present invention is to provide a light modulation element and a projector that can prevent thermal deterioration of a polarizing element and can improve the image quality by making the temperature uniform.

The light modulation element according to the present invention includes a pair of substrates each having an electrode formed on an opposite surface facing each other, and a liquid crystal sealed between the substrates, and modulates incident light according to image information. A modulation element, wherein at least one of the pair of substrates is formed of a conductive material on at least one of the facing surface side and the surface side opposite to the facing surface. And a reflective polarizing element in which a plurality of protrusions protruding from the substrate and extending in an in-plane direction of the substrate are arranged in parallel in a striped manner.
Here, the light modulation element of the present invention includes a liquid crystal sealed between at least one pair of substrates and provided with electrodes for driving the liquid crystal on the opposing surfaces between the substrates. A system etc. are not specifically limited.
In addition, the reflective polarizing element only needs to be integrally formed on at least one of the pair of substrates, and is formed only on one of the pair of substrates. A configuration in which the substrate is formed only on the other of the substrates, or a configuration in which the substrate is formed on both of the pair of substrates can be employed. Further, in these configurations, the reflective polarizing element only needs to be formed on at least one of the opposing surface side of the substrate and the surface side opposite to the opposing surface, and is formed only on the opposing surface side of the substrate. The structure which forms only in the surface side on the opposite side to the opposing surface of a board | substrate, or the structure formed in both the opposing surface side of a board | substrate and the surface side on the opposite side to a opposing surface is employable.

According to the present invention, at least one of the conventional incident-side polarizing plate and emission-side polarizing plate can be a reflective polarizing element made of a conductive material, and the reflective polarizing element is a pair. Since it is formed integrally with at least one of these substrates, the durability of the reflective polarizing element can be improved compared to the conventional reflective polarizing element comprising an absorption polarizing plate and a multilayer structure film. , Heat deterioration can be effectively prevented. Further, the configuration can be simplified and the size can be reduced as compared with the conventional configuration in which the light modulation element, the incident side polarizing plate, and the emission side polarizing plate are separated.
Further, the reflective polarizing element is made of a conductive material, and has a configuration in which a plurality of protrusions protruding from the substrate and extending in the in-plane direction of the substrate are arranged in parallel in a striped manner. It is possible to make the temperature distribution in the in-plane direction uniform, and to avoid image quality defects such as color unevenness and contrast defects in the light modulation element.
Therefore, the thermal deterioration of the reflective polarizing element can be prevented, and the temperature of the light modulation element can be made uniform to improve the image quality, thereby achieving the object of the present invention.

In the light modulation element of the present invention, the pair of substrates includes a plurality of signal lines, a plurality of switching elements connected to the plurality of signal lines, and a plurality of pixel electrodes connected to the plurality of switching elements. It is preferable that the driving substrate and a counter substrate disposed opposite to the driving substrate and having a common electrode are formed, and the reflective polarizing element is formed on the counter surface side of the counter substrate.
Here, the light modulation element of the present invention can adopt an active matrix drive system, and a switching element can be a three-terminal element such as a TFT element (Thin Film Transistor) or a two-terminal element such as a MIM (Metal Insulator Metal). .
According to the present invention, since the reflective polarizing element is formed on the opposing surface side of the opposing substrate, the reflective polarizing element is disposed close to, for example, a black matrix formed on the opposing surface side of the opposing substrate. The heat generated in the black matrix can be easily transferred to the reflective polarizing element, and the temperature distribution in the in-plane direction of the light modulation element can be easily made uniform.

In the light modulation element of the present invention, the reflective polarizing element has the plurality of protrusions extending outside the image forming region of the light modulation element, and ends in the extending direction are electrically connected to each other. It is preferable to be electrically connected to the common electrode.
In the present invention, the plurality of protrusions extend outside the image forming region of the light modulation element, and the ends in the extending direction are electrically connected to each other, so that the heat transferable range in the reflective polarizing element is expanded. The temperature distribution in the in-plane direction on the counter substrate can be made uniform, and the image quality can be improved. Further, all the plurality of protrusions can be set to the same potential, and the plurality of protrusions are electrically connected to the common electrode, so that the potential of the common electrode can be easily uniformed. As a result, the potential of the common electrode can be made uniform to further improve the image quality of the light modulation element.
Moreover, since it becomes possible to make all the some protrusion parts into the same electric potential, a reflective polarizing element can be functioned as a common electrode, for example. In such a configuration, the common electrode and the reflective polarizing element can be formed as one member, and the light modulation element can be easily manufactured and the manufacturing cost can be reduced.

In the light modulation element of the present invention, the pair of substrates includes a plurality of signal lines, a plurality of switching elements connected to the plurality of signal lines, and a plurality of pixel electrodes connected to the plurality of switching elements. A driving substrate and a counter substrate disposed opposite to the driving substrate and having a common electrode are formed, and the reflective polarizing element is formed on the surface of the counter substrate opposite to the counter surface. preferable.
Here, the light modulation element of the present invention can adopt an active matrix driving method similarly to the light modulation element described above, and the same switching element as described above can be adopted as a switching element.
According to the present invention, since the reflective polarizing element is formed on the surface opposite to the facing surface of the counter substrate, the temperature distribution in the in-plane direction of the light modulation element is mainly improved by improving the heat dissipation characteristics of the counter substrate. The light modulation element can be easily manufactured without changing the design of the electrodes or the like between the pair of substrates.

In the light modulation element of the present invention, the pair of substrates includes a plurality of signal lines, a plurality of switching elements connected to the plurality of signal lines, and a plurality of pixel electrodes connected to the plurality of switching elements. A driving substrate and a counter substrate disposed opposite to the driving substrate and having a common electrode are configured, and the reflective polarizing element is formed on a surface side opposite to the facing surface of the driving substrate. preferable.
Here, the light modulation element of the present invention can adopt an active matrix driving method similarly to the light modulation element described above, and the same switching element as described above can be adopted as a switching element.
According to the present invention, since the reflective polarizing element is formed on the surface side opposite to the facing surface of the drive substrate, the temperature distribution in the in-plane direction of the light modulation element is mainly improved by improving the heat dissipation characteristics of the drive substrate. The light modulation element can be easily manufactured without changing the design of the electrodes or the like between the pair of substrates.

In the light modulation element of the present invention, it is preferable that the plurality of protrusions are made of aluminum.
According to the present invention, the temperature distribution in the in-plane direction of the light modulation element can be easily made uniform by configuring the plurality of protrusions from aluminum having good thermal conductivity.
Further, for example, when the reflective polarizing element is integrally formed on the opposing surface side of the opposing substrate and also functions as a common electrode, the reflective polarizing element is made of aluminum, so that the conventional ITO ( Compared to a common electrode composed of an (Indium Tin Oxide) film, the common electrode can have a low electric resistance, and the potential of the common electrode can be easily made uniform. As a result, the potential of the common electrode can be made uniform to further improve the image quality of the light modulation element.

In the light modulation element according to the aspect of the invention, the reflective polarizing element has the plurality of protrusions extending outside the image forming region of the light modulation element, and end portions in the extending direction are connected to each other so that heat can be transferred to each other. Preferably it is.
According to the present invention, the plurality of protrusions extend to the outside of the image forming region of the light modulation element, and the ends in the extending direction are connected to each other so as to be able to transfer heat. As a result, the temperature distribution in the in-plane direction of the light modulation element can be made more uniform, and the image quality can be further improved.

A projector according to the present invention includes the light modulation element described above and a projection optical device that enlarges and projects an optical image modulated by the light modulation element.
According to the present invention, since the projector includes the light modulation element described above, the projector can enjoy the same operations and effects as the light modulation element described above.
Further, since the projector includes a light modulation element with improved image quality, a clear image can be displayed on the screen by the projection optical device.

[First embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
[Projector structure]
FIG. 1 is a schematic diagram illustrating an optical system of a projector 1 including a light modulation element according to the present embodiment.
The projector 1 modulates the light beam emitted from the light source according to the image information to form an optical image, and enlarges and projects it on the screen. The projector 1 includes a light source device 10, a uniform illumination optical system 20, a color separation optical system 30, a relay optical system 35, an optical device 40, and a projection lens 50 as a projection optical device. The optical elements constituting the optical systems 20 to 35 are positioned and adjusted and accommodated in the optical component casing 2 in which a predetermined illumination optical axis A is set.

  The light source device 10 illuminates the optical device 40 by emitting light beams emitted from the light source lamp in a certain direction. As shown in FIG. 1, the light source device 10 includes a light source lamp 11, a reflector 12, and a parallelizing concave lens 13. The light beam emitted from the light source lamp 11 is emitted as convergent light to the front side of the apparatus by the reflector 12, collimated by the collimating concave lens 13, and emitted to the uniform illumination optical system 20. Here, as the light source lamp 11, a halogen lamp, a metal halide lamp, or a high-pressure mercury lamp is frequently used. Furthermore, instead of the reflector 12 and the collimating concave lens 13, a parabolic mirror may be used.

The uniform illumination optical system 20 divides the light beam emitted from the light source device 10 into a plurality of partial light beams, and uniformizes the in-plane illuminance of the illumination area. As shown in FIG. 1, the uniform illumination optical system 20 includes a first lens array 21, a second lens array 22, a polarization conversion element 23, a superimposing lens 24, and a reflection mirror 25.
The first lens array 21 divides the light beam emitted from the light source lamp 11 into a plurality of partial light beams, and includes a plurality of small lenses arranged in a matrix in a plane orthogonal to the illumination optical axis A. Composed.
The second lens array 22 is an optical element that collects a plurality of partial light beams divided by the first lens array 21 described above, and in the same manner as the first lens array 21, a matrix is formed in a plane orthogonal to the illumination optical axis A. Although the configuration includes a plurality of small lenses arranged in a shape, since the purpose is to collect light, the contour shape of each small lens corresponds to the shape of an image forming area of a liquid crystal panel, which will be described later, constituting the optical device 40 You don't have to.

The polarization conversion element 23 aligns the polarization direction of each partial light beam divided by the first lens array 21 with linear polarization in substantially one direction.
Although not shown, the polarization conversion element 23 has a configuration in which polarization separation films and reflection mirrors that are inclined with respect to the illumination optical axis A are alternately arranged. The polarization separation film transmits one polarized light beam among the P-polarized light beam and S-polarized light beam included in each partial light beam, and reflects the other polarized light beam. The other polarized light beam reflected is bent by the reflecting mirror and emitted in the emission direction of the one polarized light beam, that is, the direction along the illumination optical axis A. Any of the emitted polarized light beams is polarized and converted by a phase difference plate provided on the light beam exit surface of the polarization conversion element 23, and the polarization directions of almost all the polarized light beams are aligned. By using such a polarization conversion element 23, it is possible to align the light beam emitted from the light source lamp 11 with a polarized light beam in substantially one direction, so that the utilization factor of the light source light used in the optical device 40 is improved. Can do.

The superimposing lens 24 condenses a plurality of partial light beams that have passed through the first lens array 21, the second lens array 22, and the polarization conversion element 23, and superimposes them on an image forming area of a liquid crystal panel, which will be described later, constituting the optical device 40. This is an optical element. In this example, the superimposing lens 24 is a spherical lens having a flat end surface on the incident side and a spherical end surface on the exit side of the light beam transmission region, but an aspherical lens can also be used.
The light beam emitted from the superimposing lens 24 is bent by the reflection mirror 25 and emitted to the color separation optical system 30.

The color separation optical system 30 includes two dichroic mirrors 31 and 32 and a reflection mirror 33, and a plurality of partial light beams emitted from the uniform illumination optical system 20 by the dichroic mirrors 31 and 32 are converted into red (R), It has a function of separating light of three colors, green (G) and blue (B).
The dichroic mirrors 31 and 32 are optical elements on which a wavelength selection film that reflects a light beam in a predetermined wavelength region and transmits a light beam of another wavelength is formed on a substrate. The dichroic mirror 31 disposed in the preceding stage of the optical path. Is a mirror that transmits red light and reflects other color light. The dichroic mirror 32 disposed in the latter stage of the optical path is a mirror that reflects green light and transmits blue light.

  The relay optical system 35 includes an incident side lens 36, a relay lens 38, and reflection mirrors 37 and 39, and has a function of guiding the blue light transmitted through the dichroic mirror 32 constituting the color separation optical system 30 to the optical device 40. Have. The reason why such a relay optical system 35 is provided in the optical path of the blue light is that the optical path length of the blue light is longer than the optical path lengths of the other color lights, so that the light use efficiency is reduced due to the divergence of light. It is for preventing. In this example, since the optical path length of blue light is long, such a configuration is used. However, a configuration in which the optical path length of red light is increased is also conceivable.

  The red light separated by the dichroic mirror 31 described above is bent by the reflection mirror 33 and then supplied to the optical device 40 via the field lens 41. The green light separated by the dichroic mirror 32 is supplied to the optical device 40 through the field lens 41 as it is. Further, the blue light is condensed and bent by the lenses 36 and 38 and the reflecting mirrors 37 and 39 constituting the relay optical system 35 and supplied to the optical device 40 via the field lens 41. Note that the field lens 41 provided in the front stage of the optical path of each color light of the optical device 40 is provided to convert each partial light beam emitted from the second lens array 22 into a light beam parallel to the illumination optical axis A. ing.

  The optical device 40 modulates an incident light beam according to image information to form a color image. The optical device 40 includes three light modulation devices 42 and a cross dichroic prism 43, and the light modulation device 42 and the cross dichroic prism 43 are integrally unitized.

FIG. 2 is an exploded perspective view showing the structure of the light modulation device 42.
The three light modulators 42 modulate the three color lights emitted from the color separation optical system 30 according to image information, respectively, to form an optical image. As shown in FIG. 2, each light modulation device 42 includes a light modulation element 421 and a holding frame 422. Here, the detailed structure of the light modulation element 421 will be described later.

The holding frame 422 accommodates and holds the light modulation element 421 and is made of a heat conductive material. As shown in FIG. 2, the holding frame 422 includes a storage portion 4221 and a fixing plate 4222.
The accommodating portion 4221 accommodates and holds the light modulation element 421, and is formed in a substantially rectangular frame shape having an opening 4221A corresponding to the image forming area of the light modulation element 421.
In the storage portion 4221, holes 4221 </ b> B are formed at the four corners. For example, a pin-shaped member (not shown) coated with an adhesive is inserted into the hole 4221B, and the tip of the pin-shaped member is brought into contact with the light beam incident end surface of the cross dichroic prism 43, whereby each light is transmitted by the pin-shaped member. A modulation device 42 is fixed to each light beam incident end face of the cross dichroic prism 43. The configuration is not limited to the configuration in which the light modulation device 42 is fixed to the cross dichroic prism 43, and may be configured separately.
Further, in the storage portion 4221, a hook engaging portion 4221 </ b> C for engaging with the fixing plate 4222 is formed at a substantially central portion of the side surface.

The fixing plate 4222 presses and fixes the light modulation element 421 housed in the housing part 4221 against the housing part 4221 from the light beam exit side, and in the image forming area of the light modulation element 421, similarly to the housing part 4221. It is formed in a substantially rectangular frame shape having a corresponding opening 4222A.
In the fixed plate 4222, hooks 4222 </ b> B corresponding to the hook engaging portions 4221 </ b> C of the storage portion 4221 are formed on the left and right end edges.
Further, a frame-like member 4222C is projected from the edge of the light incident side of the fixed plate 4222 at the periphery of the opening 4222A. Note that the fixing plate 4222 and the frame-like member 4222C may be integrated by bonding with an adhesive or the like, or may be integrated by welding or the like. Further, the same material may be formed as a molded product that is integrally formed by molding, for example, by injection molding or the like.

The frame-like member 4222C is in contact with a later-described dust-proof glass and / or driving substrate of the light modulation element 421.
Specifically, the shape of the frame-shaped member 4222C that comes into contact with the drive substrate includes the following configuration. For example, the frame-like member 4222C has a shape larger than the outer peripheral shape of the dust-proof glass of the light modulation element 421, and has a stepped portion 4222C1 at the tip of the inner peripheral edge as shown in FIG. The stepped portion 4222C1 has a shape that allows the drive substrate to be fitted to the frame-like member 4222C, and the height dimension thereof is larger than the thickness dimension of the dust-proof glass.

Further, the shape of the frame-shaped member 4222C contacting the dust-proof glass includes the following configuration. For example, the frame-like member 4222C has a shape that allows the dust-proof glass to be fitted to the inner periphery thereof, and has a stepped portion 4222C1 at the tip portion of the inner periphery as shown in FIG. The stepped portion 4222C1 has a shape in which the drive substrate can be freely fitted and disposed on the frame-like member 4222C, and the height dimension thereof is smaller than the thickness dimension of the dust-proof glass.
Furthermore, the shape of the frame-shaped member 4222C that contacts both the dust-proof glass and the drive substrate includes the following configuration. For example, the frame-like member 4222C has a shape that allows the dust-proof glass to be fitted to the inner periphery thereof, and has a height that is substantially the same as the thickness of the dust-proof glass.

The storage unit 4221 and the fixing plate 4222 described above are made of, for example, invar and an iron-nickel alloy such as 42Ni—Fe, a magnesium alloy, an aluminum alloy, or a heat conductive resin. Note that the storage portion 4221 and the fixing plate 4222 may be made of the same material or different materials. Further, the fixing plate 4222 and the frame-like member 4222C may be made of the same material or different materials.
By storing and holding the light modulation element 421 in the holding frame 422 described above, a sufficient contact area between the light modulation element 421 and the holding frame 422 can be secured, and the heat dissipation characteristics of the light modulation element 421 can be improved.

  The cross dichroic prism 43 combines the optical images emitted from the respective light modulation devices 42 and modulated for each color light to form a color image. Although not specifically shown, the cross dichroic prism 43 includes a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light that is approximately X along the interface of four right-angle prisms. The three color lights are synthesized by these dielectric multilayer films.

[Structure of light modulation element]
FIG. 3 is a cross-sectional view schematically showing the structure of the light modulation element 421.
The light modulation element 421 is an active matrix drive type liquid crystal panel, and as shown in FIG. 3, a pair of substrates 4211 and 4212 made of glass or the like, and a liquid crystal sealed between the pair of substrates 4211 and 4212. A layer 4213 and dust-proof glasses 4214 and 4215 attached to the pair of substrates 4211 and 4212.

FIG. 4 is a plan view schematically showing the end face of the substrate 4211 on the light beam incident side.
The substrate 4211 is a driving substrate for driving the liquid crystal layer 4213, and has a plurality of data lines 4211A and a plurality of scanning lines 4211B serving as signal lines and a plurality of scanning lines 4211B on the light beam incident side end surface as shown in FIG. Pixel electrode 4211C and a plurality of switching elements 4211D are formed. FIG. 4 is a diagram schematically illustrating the data line 4211A, the scanning line 4211B, the pixel electrode 4211C, and the switching element 4211D formed on the end surface of the light incident side of the substrate 4211. The number, size, and the like of 4211A, the scanning line 4211B, the pixel electrode 4211C, and the switching element 4211D are not limited to those illustrated in FIG. The same applies to the pixel electrode 4211C shown in FIG.

The plurality of data lines 4211A are arranged in parallel to each other, and a video signal is sent from a control circuit (not shown), and is made of a metal such as aluminum.
The plurality of scanning lines 4211B are arranged in a direction orthogonal to the plurality of data lines 4211A, and are sequentially applied with scanning pulses from a control circuit (not shown). For example, polycrystalline silicon, metal such as aluminum, tantalum, etc. Etc.
The plurality of pixel electrodes 4211C are electrodes to which the voltage of the video signal through the data line 4211A is appropriately applied depending on the conduction or non-conduction state of the plurality of switching elements 4211D, and are made of, for example, a transparent conductor such as ITO. .
The switching element 4211D is formed of, for example, a three-terminal element such as a TFT element, the gate is connected to the scanning line 4211B, the source is connected to the data line 4211A, and the drain is connected to the pixel electrode 4211C.

A scanning pulse is sequentially applied to each scanning line 4211B for each frame period from a control circuit (not shown). A predetermined switching element 4211D is selected by this scanning pulse, and is turned on or off. Here, the voltage of the video signal supplied to the data line 4211A is applied to the pixel electrode 4211C corresponding to the switching element 4211D through the switching element 4211D in the conductive state.
Although not shown in the figure on the end surface of the light incident side of the substrate 4211, in addition to the above-described configuration, the pixel electrode 4211C is arranged in the vicinity of the switching element 4211D and in the non-selection period in which the switching element 4211D is non-conductive. An auxiliary capacitor (not shown) is formed so that the voltage applied to can be held. In addition, an alignment film is formed as the uppermost layer on the light incident side end surface of the substrate 4211, and this film is rubbed.

FIG. 5 is a perspective view schematically showing the end surface of the substrate 4211 on the light beam exit side.
As shown in FIG. 5, among the light beams emitted from the substrate 4211, a light beam having a predetermined polarization axis is emitted to the end surface on the light beam emission side of the substrate 4211, and a light beam having another polarization axis is reflected. An exit side polarization element 4211E as a reflective polarization element is integrally formed.
The exit-side polarizing element 4211E is made of a conductive material, and has a configuration in which a plurality of protrusions 4211E1 projecting in the light beam exit direction and extending in a predetermined direction are arranged in parallel in a striped pattern. In the present embodiment, the plurality of protrusions 4211E1 are formed by performing vapor deposition, etching processing, or the like on the light emitting side end surface of the substrate 4211. FIG. 5 is a diagram schematically illustrating the exit-side polarizing element 4211E formed on the end surface on the light-beam exit side of the substrate 4211. The height dimension, pitch dimension, and the like of the plurality of protrusions 4211E1 are as follows. The ratio between the pitch dimension and the width dimension is not limited to that shown in FIG.
In the present embodiment, the plurality of protrusions 4211E1 have a height dimension H of 100 to 150 nm, a pitch dimension P of 150 to 200 nm, and a ratio W / P of the pitch dimension P to the width dimension W of 0.4 to 0.00. 5 is formed.
In such an exit-side polarizing element 4211E, the light beam R1 incident through the liquid crystal layer 4213 (FIG. 3) has a polarization axis parallel to the extending direction of the plurality of protrusions 4211E1 as shown in FIG. The polarized light R2 having a component is reflected, and the polarized light R3 having a polarization axis component orthogonal to the extending direction is transmitted.

FIG. 6 is a plan view schematically showing the end surface of the substrate 4212 on the light beam exit side.
As shown in FIG. 3, the substrate 4212 is a counter substrate that is disposed to face the substrate 4211 with a predetermined interval through a sealant 4216, and the liquid crystal layer 4213 is hermetically sealed between the substrate 4211 and the substrate 4211. .
As shown in FIG. 3 or FIG. 6, a black matrix 4212A and a common electrode 4212B are formed on the end surface of the substrate 4212 on the light emission side.

  As shown in FIG. 6, the black matrix 4212A is formed in a matrix so as to correspond to the positions of the data line 4211A, the scanning line 4211B, and the switching element 4211D of the substrate 4211, and blocks incident light flux. For example, it is made of a metal such as chromium or titanium. By blocking the incident light flux by the black matrix 4212A, the temperature rise of the switching element 4211D can be suppressed, and the leakage current due to the light of the switching element 4211D can be reduced. For this reason, it can be prevented that the charge retention characteristics of each pixel deteriorate and the contrast of the light modulation element 421 is reduced.

The common electrode 4212B functions not only as an electrode to which a predetermined voltage Vcom is applied, but also as a reflective polarizing element. For example, the black matrix 4212A is covered with a flattening film (not shown) made of a transparent acrylic resin. And formed on the planarizing film.
As shown in FIG. 6, the common electrode 4212B is made of a metal material, like the exit-side polarizing element 4211E of the substrate 4211, and has a plurality of protrusions 4212B1 that protrude in the light emission direction and extend in a predetermined direction. It has the structure arranged in parallel in the shape. FIG. 6 is a diagram schematically illustrating the black matrix 4212A and the common electrode 4212B formed on the end surface on the light emission side of the substrate 4212. The shape of the black matrix 4212A and a plurality of common electrodes 4212B are shown in FIG. The height dimension, the pitch dimension, the ratio between the pitch dimension and the width dimension, and the like of the protrusion 4212B1 are not limited to those illustrated in FIG. The same applies to FIG.

In the present embodiment, the plurality of protrusions 4212B1 are formed by subjecting aluminum to vapor deposition and etching on the light beam incident end surface of the substrate 4212 in the same manner as the protrusions 4211E1 of the substrate 4211. The pitch dimension and the ratio between the pitch dimension and the width dimension are substantially the same as those of the plurality of protrusions 4211E1 in the substrate 4211. By forming the plurality of protrusions 4212B1 with the pitch dimension and the width dimension, the plurality of protrusions 4212B1 are formed finer than the individual dimensions and pitch dimensions of the pixel electrode 4211C on the substrate 4211. Accordingly, the common electrode 4212B is considered to be formed substantially uniformly with respect to the pixel electrode 4211C.
Further, since the common electrode 4212B has the same potential across the common electrode 4212B with the applied voltage Vcom, as shown in FIG. 6, the ends in the extending direction of the plurality of protrusions 4212B1 are image forming regions. Are connected to each other outside (in FIG. 6, outside the region where the black matrix 4212A is formed).
Although not shown in the drawing, the alignment film is formed as the uppermost layer on the light emitting side end face of the substrate 4212, and this film is rubbed.

Here, the plurality of protrusions 4212B1 in the common electrode 4212B are set so that the extending direction thereof is along the direction orthogonal to the polarization axis that is substantially aligned in the polarization conversion element 23 of the uniform illumination optical system 20. Has been. For this reason, although not specifically shown, among the light beams incident on the light modulation element 421, that is, among the light beams having the polarization axes that are substantially aligned by the polarization conversion element 23 of the uniform illumination optical system 20, Polarized light having the polarization axis component is transmitted through the common electrode 4212B, and polarized light other than the polarization axis component is reflected by the common electrode 4212B.
The plurality of protrusions 4212B1 in the common electrode 4212B are set so that the extending direction thereof is substantially orthogonal to the extending direction of the plurality of protrusions 4211E1 in the substrate 4211 as shown in FIG. . That is, the polarization axis of the light beam passing through the common electrode 4212B and the polarization axis of the light beam passing through the exit-side polarization element 4211E of the substrate 4211 are set to be substantially orthogonal.

The liquid crystal layer 4213 is made of, for example, a TN (twisted nematic) liquid crystal, and alignment of liquid crystal molecules sandwiched between the pixel electrode 4211C and the common electrode 4212B in accordance with a voltage applied to the pixel electrode 4211C. Is controlled, whereby the rotation of the polarization axis of the incident light beam is controlled to perform modulation. For example, when a voltage is applied to the pixel electrode 4211C, the light beam that has passed through the common electrode 4212B of the substrate 4212 reaches the substrate 4211 without rotating its polarization axis when passing through the liquid crystal layer 4213. The light is reflected by the exit side polarization element 4211E. That is, the display is black. Further, for example, when no voltage is applied to the pixel electrode 4211C, the light beam that has passed through the common electrode 4212B of the substrate 4212 is rotated by about 90 ° when passing through the liquid crystal layer 4213, and the exit side polarization element 4211E is transmitted. That is, white display is performed.
Note that the liquid crystal of the liquid crystal layer 4213 is not limited to the TN type, and for example, a horizontal alignment type, a vertical alignment type, a polymer dispersion type, a memory type such as a ferroelectric, or the like can be appropriately employed.

  The dust-proof glasses 4214 and 4215 are affixed to the outer surfaces of the pair of substrates 4211 and 4212 (light emission side end surface and light incident side end surface). These dustproof glasses 4214 and 4215 cover the outer surface of the substrate to prevent dust from adhering. Even if dust adheres to the outer surfaces of the dust-proof glasses 4214 and 4215, since the focus state does not occur, there is no display shade on the projected image.

  In the first embodiment described above, the exit-side polarizing element 4211E and the common electrode 4212B formed on the substrates 4211 and 4212 are reflective polarizing elements made of aluminum, so that the conventional absorption-type polarizing plate and multilayer structure film are used. Compared with the reflection type polarizing element, the durability of the exit side polarizing element 4211E and the common electrode 4212B can be improved, and thermal deterioration can be effectively prevented. In addition, the configuration can be simplified and the projector 1 can be downsized as compared with the conventional configuration in which the light modulation element, the incident side polarizing plate, and the emission side polarizing plate are separated.

The exit side polarization element 4211E and the common electrode 4212B are made of aluminum, and a plurality of protrusions 4211E1 and 4212B1 projecting from the substrates 4211 and 4212 and extending in the in-plane direction of the substrates 4211 and 4212 are striped. Because of the parallel arrangement, the temperature distribution in the in-plane direction of the light modulation element 421 can be made uniform, and the occurrence of image quality defects such as color unevenness and contrast failure in the light modulation element 421 can be avoided.
In particular, the common electrode 4212B is formed on the end surface of the light emitting side of the substrate 4212, and is disposed in the vicinity of the black matrix 4212A. Therefore, heat generated in the black matrix 4212A is well transmitted to the common electrode 4212B, and the light modulation element The temperature distribution in the in-plane direction at 421 can be easily made uniform.
Further, the common electrode 4212B has a plurality of protrusions 4212B1 extending outside the image forming area of the light modulation element 421, and ends in the extending direction are connected to each other. By enlarging, the temperature distribution in the in-plane direction of the light modulation element 421 can be further uniformed, and the image quality can be further improved.

Further, by connecting the ends in the extending direction of the plurality of protrusions 4212B1 in the common electrode 4212B to each other, the plurality of protrusions 4212B1 can be set to the same potential, and the function as a reflective polarizing element can be achieved. Also, it can function as an electrode to which a predetermined voltage Vcom is applied. Therefore, by providing the common electrode 4212B with the functions of both the electrode and the reflective polarizing element, members can be omitted, and the light modulation element 421 can be easily manufactured and the manufacturing cost can be reduced.
Further, since the common electrode 4212B is made of aluminum, the common electrode 4212B can be a common electrode having a lower electric resistance than the common electrode made of a conventional ITO film, and the potential of the common electrode 4212B is made uniform. Easy configuration. Therefore, the potential of the common electrode 4212B can be made uniform, and the image quality in the light modulation element 421 can be further improved.

Furthermore, since the exit-side polarizing element 4211E is formed on the end face of the light-emitting side of the substrate 4211, the temperature distribution in the in-plane direction of the light modulation element 421 is made uniform mainly by improving the heat dissipation characteristics of the substrate 4211. As compared with the configuration formed on the end facet on the light incident side of the substrate 4211, the optical modulation is performed without changing the design of the data line 4211A, the scanning line 4211B, the pixel electrode 4211C, and the switching element 4211D on the substrate 4211. The element 421 can be easily manufactured.
Since the projector 1 includes the light modulation element 421 with improved image quality, the projection lens 50 can display a clear image on the screen.

[Second Embodiment]
Next, 2nd Embodiment of this invention is described based on drawing.
In the following description, the same structure and the same members as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted or simplified.
In the first embodiment, the common electrode 4212B of the substrate 4212 has both functions of an electrode and an incident side polarizing plate.
On the other hand, in the second embodiment, the common electrode 5212B of the substrate 5212 has a function only as an electrode, and an incident side polarizing element 5212C as a reflection type polarizing element is formed on the light beam incident side end surface of the substrate 5212. Yes. Other configurations are the same as those in the first embodiment.

Specifically, FIG. 7 is a cross-sectional view schematically showing the structure of the light modulation element 521 in the second embodiment.
The common electrode 5212B formed on the substrate 5212 is an electrode to which a predetermined voltage Vcom is applied, and is made of, for example, an ITO film that is a transparent conductive film. Although not specifically shown, the common electrode 5212B is uniformly formed on the flattening film by covering the black matrix 4212A with a flattening film (not shown) made of a transparent acrylic resin, for example.
Although not specifically shown, the incident-side polarizing element 5212C protrudes in the light beam incident direction and is similar to the common electrode 4212B in the substrate 4212 described in the first embodiment, and includes a plurality of protrusions 4211E1 in the substrate 4211. A plurality of protrusions 5212C1 extending in a direction orthogonal to the extending direction are arranged in parallel in a striped manner.
FIG. 7 is a diagram schematically showing a cross-sectional structure of the light modulation element 521. The number and size of the pixel electrodes 4211C, the height dimensions of the plurality of protrusions 4211E1 in the exit side polarization element 4211E, The pitch dimension, the ratio between the pitch dimension and the width dimension, the shape of the black matrix 4212A, and the shape of the plurality of protrusions 4212B1 in the incident-side polarizing element 5212C are not limited to those shown in FIG.
In the present embodiment, the material and shape (height dimension, pitch dimension, and ratio of pitch dimension to width dimension) of the plurality of protrusions 5212C1 in the incident-side polarizing element 5212C are the plurality of protrusions 4211E1 in the substrate 4211. Is substantially the same. In addition, although a specific illustration of the plurality of protrusions 5212C1 in the incident-side polarizing element 5212C is omitted, unlike the common electrode 4212B in the substrate 4212 described in the first embodiment, ends in the extending direction are connected to each other. It has not been.

  In the second embodiment described above, since the incident side polarization element 5212C having substantially the same configuration as the common electrode 4212B is formed on the light beam incident side end face of the substrate 5212 as compared with the first embodiment, In addition, the heat dissipation characteristics of the substrate 5212 can be improved to make the temperature distribution of the light modulation element 521 uniform, and the light modulation element 521 can be easily formed without changing the design of the black matrix 4212A and the common electrode 5212B on the substrate 5212. Can be manufactured.

[Modification of Embodiment]
Although the present invention has been described with reference to preferred embodiments, the present invention is not limited to these embodiments, and various improvements and design changes can be made without departing from the scope of the present invention. It is.
In each of the above embodiments, the light modulation elements 421 and 521 have been described as active matrix drive type light modulation elements, but the present invention is not limited thereto. The light modulation element of the present invention may be any structure as long as it has a configuration in which liquid crystal is sealed between at least one pair of substrates and electrodes for driving the liquid crystal are provided on the opposing surfaces between the substrates. The format is not limited. For example, although the light modulation elements 421 and 521 have been described as transmissive light modulation elements, a reflection light modulation element including a reflective layer, or a structure having both a transmission type and a reflection type may be used. Further, the present invention is not limited to the active matrix driving method described in each embodiment, and a passive matrix driving method may be adopted. At this time, the pixel electrode 4211C and the common electrodes 4212B and 5212B may have a shape corresponding to the driving method. Furthermore, the switching element 4211D is not limited to the three-terminal element of the TFT element described in the above embodiments, and a two-terminal element such as MIM may be employed.

  In each of the embodiments described above, the light modulation elements 421 and 521 are configured such that the substrates 4212 and 5212 that are the counter substrates are disposed on the light beam incident side, and the substrate 4211 that is the driving substrate is disposed on the light beam emission side. Not limited to this, the substrate 4211 may be disposed on the light beam incident side, and the substrates 4212 and 5212 may be disposed on the light beam emission side. At this time, the black matrix 4212A may be formed on the substrate 4211 so as to be positioned in front of the optical path of the switching element 4211D formed on the substrate 4211.

In each of the above embodiments, the reflective polarizing element may be formed integrally with at least one of the pair of substrates 4211 and 4212 (5212). Further, in this configuration, the reflective polarizing element may be formed on at least one of the opposing surface side of the substrates 4211 and 4212 (5212) and the surface side opposite to the opposing surface. That is, not only the configuration described in the above embodiments but also the following configuration may be adopted.
For example, in each of the above embodiments, the exit-side polarizing element 4211E as the reflective polarizing element is integrally formed on the light-incident side end face and / or the light-exit side end face of the dust-proof glass 4214, or the light modulation element 421. , 521 and a separate body. That is, a configuration in which the reflective polarizing element (common electrode 4212B, incident-side polarizing element 5212C) is formed only on one of the substrates 4212 and 5212 (5212) may be employed. When the exit side polarization element 4211E is separated from the light modulation elements 421 and 521, it may be configured as an absorption type polarization plate as in the past, or as a reflection type polarization plate made of a multilayer structure film. It may be configured.

  Similarly, in each of the embodiments, the common electrode 4212B and the incident side polarizing element 5212C as the reflective polarizing elements are integrally formed on the light incident side end face and / or the light emitting side end face of the dustproof glass 4214, or , Separate from the light modulation elements 421 and 521. That is, a configuration in which the reflective polarizing element (exit-side polarizing element 4211E) is formed only on one of the substrates 4211 and 4212 (5212) may be employed. In the first embodiment, when the common electrode 4212B is arranged as described above, a common electrode such as an ITO film functioning as an electrode is provided on the light emission side end surface of the substrate 4212, as in the second embodiment. Shall be formed. Further, as described above, when the common electrode 4212B and the incident side polarization element 5212C are separated from the light modulation elements 421 and 521, they may be configured as absorption polarizing plates as in the past, or may have a multilayer structure. You may comprise as a reflective polarizing plate which consists of a film.

  Further, for example, in the first embodiment, a configuration in which a reflective polarizing element having the same configuration as that of the exit-side polarizing element 4211E is integrally formed on the light-incident-side end face of the substrate 4211, a light-incident-side end face, and a light-exiting side. It is good also as a structure integrally formed in both of an end surface, respectively. Similarly, the common electrode 4212B and the incident-side polarizing element 5212C may be integrally formed on both the light beam incident side end surface and the light beam emission side end surface of the substrate 4212, respectively.

  In each of the embodiments described above, the plurality of protrusions 4211E1 and 5212C1 in the exit-side polarizing element 4211E and the incident-side polarizing element 5212C as the reflective polarizing elements are configured such that the end portions in the extending direction are not connected to each other. Not limited to this, a plurality of protrusions 4211E1 and 5212C1 may be extended to the outside of the image forming area of the light modulation elements 421 and 521, and end portions in the extending direction may be connected to each other. Moreover, it is good also as a structure connected so that heat transfer may mutually be carried out with another heat conductive material other than the structure where the extension direction edge parts were connected mutually. With such a configuration, the heat transferable range of the exit side polarization element 4211E and the incidence side polarization element 5212C is expanded, the temperature distribution in the in-plane direction of the light modulation elements 421 and 521 is further uniformed, and the image quality is further improved. it can.

In the first embodiment, the extending direction ends of the plurality of protrusions 4212B1 in the common electrode 4212B are connected to each other. However, it is only necessary that the extending direction ends are electrically connected to each other. It is good also as a structure by which the extension direction edge part is mutually electrically connected by another electroconductive material.
In each of the embodiments described above, the plurality of protrusions 4211E1, 4212B1, and 5212C1 in the exit-side polarizing element 4211E, the common electrode 4212B, and the incident-side polarizing element 5212C as the reflective polarizing elements are made of aluminum. Any material may be used as long as it is a conductive material, for example, silver or the like.

  In the first embodiment, the common electrode 4212B is formed on the end surface of the light emitting side of the substrate 4212 and has both functions as an electrode and a reflective polarizing element. Both the common electrode made of an ITO film or the like and the reflective polarizing element made of aluminum or the like may be formed on the emission side end face. At this time, the plurality of protrusions in the reflective polarizing element extend outside the image forming area of the light modulation element, and end portions in the extending direction are electrically connected to each other. Further, the reflective polarizing element and the common electrode are electrically connected. In such a configuration, the potential of the common electrode can be made uniform by the reflective polarizing element, and the image quality of the light modulation element 421 can be improved. In addition, the heat transferable range of the reflective polarizing element is expanded, the temperature distribution in the in-plane direction of the substrate 4212 can be made uniform, and the image quality can be improved.

In each of the embodiments described above, the projector 1 uses the three light modulation elements 421 (521). However, the present invention is not limited to this. For example, only one light modulation element 421 (521) may be used, two light modulation elements 421 (521), or four or more light modulation elements 421 (521) may be used.
In each of the embodiments described above, the projector 1 has been described as a front type projector that performs projection from the direction in which the screen is observed. However, in the present invention, the projector 1 is a rear type projector that performs projection from the side opposite to the direction in which the screen is observed. Is also applicable.
In each of the above-described embodiments, the configuration in which the light modulation element 421 (521) is mounted on the projector 1 has been described. However, the configuration is not limited thereto, and may be mounted on other optical devices.

Although the best configuration for carrying out the present invention has been disclosed in the above description, the present invention is not limited to this. That is, the invention has been illustrated and described primarily with respect to particular embodiments, but may be configured for the above-described embodiments without departing from the scope and spirit of the invention. Various modifications can be made by those skilled in the art in terms of materials, quantity, and other detailed configurations.
Therefore, the description limited to the shape, material, etc. disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such is included in this invention.

  The light modulation element of the present invention is useful as a light modulation element used in a projector used in a home theater or a presentation because it can prevent thermal deterioration of the polarizing element and can improve the image quality by making the temperature uniform.

FIG. 2 is a schematic diagram showing an optical system of a projector including the light modulation element according to the first embodiment. The disassembled perspective view which shows the structure of the light modulation apparatus in the said embodiment. Sectional drawing which shows typically the structure of the light modulation element in the said embodiment. The top view which shows typically the light beam entrance side end surface of the drive board | substrate in the said embodiment. The perspective view which shows typically the light beam emission side end surface of the drive board | substrate in the said embodiment. The top view which shows typically the light beam emission side end surface of the opposing board | substrate in the said embodiment. Sectional drawing which shows typically the structure of the light modulation element in 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Projector, 50 ... Projection lens (projection optical apparatus), 421,521 ... Light modulation element, 4211 ... Substrate (drive substrate), 4211A ... Data line (signal line), 4211B ... Scanning line (signal line), 4211C ... Pixel electrode, 4211D ... Switching element, 4211E ... Emission-side polarizing element (reflection type polarizing element), 4211E1, 4212B1, 5212C1 ... Ridge , 4212, 5212... Substrate (counter substrate), 4212B... Common electrode (reflection type polarization element), 5212C... Incident side polarization element (reflection type polarization element).

Claims (8)

A light modulation element that includes a pair of substrates each having electrodes formed on opposing surfaces and a liquid crystal sealed between the substrates, and modulates an incident light beam according to image information,
At least one of the pair of substrates is made of a conductive material on at least one of the facing surface and the surface opposite to the facing surface, and protrudes from the substrate. A light-polarizing element in which a plurality of protrusions extending in an in-plane direction of the substrate are integrally formed in a stripe pattern and formed in an integrated manner. The light modulation element according to claim 1,
The pair of substrates includes a drive substrate having a plurality of signal lines, a plurality of switching elements connected to the plurality of signal lines, and a plurality of pixel electrodes connected to the plurality of switching elements; It is arranged with a counter substrate that is arranged opposite to and has a common electrode,
The light-modulating element, wherein the reflective polarizing element is formed on the opposing surface side of the opposing substrate. The light modulation element according to claim 2,
In the reflective polarizing element, the plurality of protrusions extend outside the image forming region of the light modulation element, the extending direction end portions are electrically connected to each other, and are electrically connected to the common electrode. A light modulation element which is connected. The light modulation element according to any one of claims 1 to 3,
The pair of substrates includes a drive substrate having a plurality of signal lines, a plurality of switching elements connected to the plurality of signal lines, and a plurality of pixel electrodes connected to the plurality of switching elements; It is arranged with a counter substrate that is arranged opposite to and has a common electrode,
The reflection type polarizing element is formed on a surface of the counter substrate opposite to the counter surface. The light modulation element according to any one of claims 1 to 4,
The pair of substrates includes a drive substrate having a plurality of signal lines, a plurality of switching elements connected to the plurality of signal lines, and a plurality of pixel electrodes connected to the plurality of switching elements; It is arranged with a counter substrate that is arranged opposite to and has a common electrode,
The reflective polarizing element is formed on an end surface of the drive substrate opposite to the facing surface. The light modulation element according to any one of claims 1 to 5,
The plurality of protrusions are made of aluminum. The light modulation element according to any one of claims 1 to 6,
In the reflective polarizing element, end portions in the extending direction of the plurality of protrusions extend outside the image forming region of the light modulation element, and the end portions in the extending direction are connected so as to be able to transfer heat to each other. A light modulation element characterized by the above.   8. A projector comprising: the light modulation element according to claim 1; and a projection optical device that enlarges and projects an optical image modulated by the light modulation element.