JP2010054654A - Electro-optical device and projector provided with the electro-optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electro-optical device and a projector provided with the electro-optical device, capable of effectively reducing occurrence of chromatic aberration of magnification. <P>SOLUTION: The electro-optical device 1 includes: an optical modulation element 20 that modulates light from a light source; a signal separation part 102 that separates input image information into color information and brightness information; a driving means 106 or the like that drives the optical modulation element so as to emit a plurality of optical images with a plurality of prescribed periods respectively on the basis of the color information; a brightness modulation element 70 that performs brightness modulation on the basis of the brightness information with respect to the plurality of optical images; a relay optical system 40 that relays the plurality of optical images between the optical modulation element and the brightness modulation element; polarizing optical systems 30, 60 that include grid polarizer WG1, etc.; a liquid crystal element 50 in which vertically aligned liquid crystal composed of vertically aligned liquid crystal molecules is held between a pair of substrates, and which inclines the liquid crystal molecules and can refract the plurality of optical images respectively; and a control means 108 that controls the liquid crystal element so as to change the inclination angle of the liquid crystal molecules in the prescribed period. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electro-optical device having a liquid crystal element and a technical field of a projector including the electro-optical device.

In recent years, display devices such as LCD (Liquid Crystal Display), EL (Electro-Luminescence) displays, plasma displays, CRTs (Cathode Ray Tubes), and projectors have been remarkably improved. Devices with comparable performance are being realized. However, regarding the luminance dynamic range, the reproduction range is about 1 to 10 ² [nit], and the number of gradations is generally 8 bits. On the other hand, human vision has a range of luminance dynamic range that can be perceived at a time of about 10 ⁻² to 10 ⁴ [nit], and the luminance discrimination capability is 0.2 [nit]. It is said to be equivalent to 12 bits. When viewing the display image of the current display device via such visual characteristics, the narrowness of the luminance dynamic range is conspicuous, and in addition, the gradation of the shadow part and highlight part is insufficient, You will feel unsatisfactory with the reality and power of the displayed image.

In CG (Computer Graphics) used in movies, games, etc., the display data (hereinafter referred to as HDR (High Dynamic Range) display data) has a luminance dynamic range and gradation characteristics close to human vision. The movement to pursue reality is becoming mainstream. However, since the performance of the display device that displays it is insufficient, there is a problem that the expressive power inherent in the CG content cannot be fully exhibited.
Furthermore, in the next OS (Operating System), adoption of a 16-bit color space is planned, and the dynamic range and the number of gradations are dramatically increased as compared with the current 8-bit color space. Therefore, it is expected that there will be an increasing demand for realizing a high dynamic range and high gradation electronic display device that can make use of the 16-bit color space.
Among display devices, a projection-type image display device (projector) such as a liquid crystal projector is capable of displaying on a large screen and is an effective display device for reproducing the reality and power of a display image. In this field, in order to solve the above problems, the following proposal has been made (for example, see Patent Document 1).

In the projection type image display device described in Patent Document 1, the light reflected in the first direction by the first light modulation element is incident on the light combining means via the second light modulation element, and the first light modulation element causes the first light modulation element to The light reflected in the direction 2 is directly incident on the light combining means, thereby improving the light utilization efficiency and realizing both the expansion of the luminance and the improvement of the gradation performance.
Japanese Patent Laying-Open No. 2005-284058

  However, the projection-type image display device described in Patent Document 1 described above complicates the device configuration by incorporating an optical system that synthesizes two separated light paths. Therefore, it is desired to provide a technique capable of expanding the luminance and improving the gradation performance without complicating the device configuration of the conventional projection type image display device.

  In addition, for example, when a wire grid type polarization separation element is used as a polarization optical system such as PBS (Polarized Beam Splitter), for example, a wire grid type polarization separation element constituted by parallel flat plates having strip-shaped aluminum portions is used. When the light is transmitted, the R light, the G light, and the B light are dispersed, resulting in variations in the magnification for projecting the R optical image, the G optical image, and the B optical image, and so-called lateral chromatic aberration is generated. There is a technical problem.

  SUMMARY An advantage of some aspects of the invention is that it provides an electro-optical device that can effectively reduce the occurrence of chromatic aberration of magnification and a projector including the electro-optical device.

(Electro-optical device)
In order to solve the above problems, an electro-optical device of the present invention is based on a light modulation element that modulates light from a light source, a signal separation unit that separates input image information into color information and luminance information, and the color information. Driving means for driving the light modulation element so as to emit a plurality of optical images respectively corresponding to the plurality of color-modulated lights at a plurality of predetermined periods, and the luminance information for the plurality of optical images. A luminance modulation element that performs luminance modulation based on the above, a relay optical system that relays the plurality of optical images between the light modulation element and the luminance modulation element, a grid polarizer, and the plurality of optical images A vertically aligned liquid crystal composed of liquid crystal molecules vertically aligned by the alignment film is sandwiched between a polarizing optical system that changes the polarization state and a pair of substrates each having an alignment film, and the liquid crystal molecules are tilted. Make And a liquid crystal element capable of refracting each of the plurality of optical images, and a control means for controlling the liquid crystal element so as to change an inclination angle of the liquid crystal molecules at one of the plurality of predetermined periods. .

  According to the electro-optical device of the present invention, the light from the light source is modulated by the light modulation element. The input image information is separated into color information and luminance information by the signal separation unit. Based on the color information, the light modulating element is driven by the driving means so that a plurality of optical images respectively corresponding to the plurality of color modulated lights are emitted at a plurality of predetermined periods. The luminance modulation element performs luminance modulation based on luminance information on the plurality of optical images. A plurality of optical images are relayed between the light modulation element and the luminance modulation element by the relay optical system. The polarization optical system includes a grid polarizer and changes the polarization state of a plurality of optical images. A typical example of the grid polarizer is a wire grid. As a result, it is possible to insert a blanking period in the luminance information, and when the object in the video moves, the gradation of the edge of the object is lowered and is prevented or suppressed from being blurredly displayed. Is possible.

  In a liquid crystal element, a vertical alignment type liquid crystal composed of liquid crystal molecules vertically aligned by an alignment film is sandwiched between a pair of substrates each having an alignment film. Each image can be refracted. The control means controls the liquid crystal element so as to change the tilt angle of the liquid crystal molecules at a predetermined period.

  Thereby, the inclination angle of the liquid crystal molecules in the vertical alignment type liquid crystal element can be changed with respect to each of the plurality of optical images. Thus, when light is transmitted through a polarizing optical system including a grid polarizer, when each of the plurality of optical images is dispersed, the refractive index of each of the plurality of optical images can be changed in a vertically aligned liquid crystal element. Therefore, the occurrence of lateral chromatic aberration can be effectively prevented. As a result, it is possible to realize high contrast, improve the dynamic range, increase the number of gradations, and expand the color reproduction range.

  For example, when a polarizing optical system including a grid polarizer such as a wire grid is used without using the liquid crystal element described above, for example, light is transmitted through a grid polarizer configured by parallel flat plates having strip-shaped aluminum portions. When transmitting, white light including, for example, R light, G light, and B light is dispersed for each color, thereby projecting a plurality of optical images such as an R optical image, a G optical image, and a B optical image, for example. There is a technical problem that variation occurs in the magnification and so-called chromatic aberration of magnification occurs.

In one aspect of the electro-optical device of the present invention, the driving unit drives the light modulation element so as to emit a plurality of time-divided optical images at the plurality of predetermined periods, and the luminance modulation element. Performs the luminance modulation on the plurality of time-divided optical images, and the control means changes the tilt angle of the liquid crystal molecules corresponding to each of the plurality of time-divided optical images. The liquid crystal element is controlled.
According to this aspect, the tilt angle of the liquid crystal molecules in the vertical alignment type liquid crystal element can be changed with high accuracy with respect to the plurality of time-divided optical images. Can be prevented.

In another aspect of the electro-optical device according to the aspect of the invention, the liquid crystal element has a first pixel region in which a plurality of first pixels are arranged, and changes a voltage applied to the first pixels. The tilt angle of the liquid crystal molecules is changed.
According to this aspect, the tilt angle of the liquid crystal molecules in the vertical alignment type liquid crystal element can be changed for each of the plurality of first pixels with respect to the plurality of optical images. Can be more effectively prevented.

In another aspect of the electro-optical device of the present invention, each of the light modulation element and the luminance modulation element includes a reflective liquid crystal light valve.
According to this aspect, it is possible to easily realize a two-modulation method that separately controls both color information and luminance information by using two types of liquid crystal light valves. In addition, simplification of the optical design of the optical system and space saving of the dimensions of the optical system can be realized, and the manufacturing cost can be reduced as compared with a three-plate optical system.

In another aspect of the electro-optical device of the present invention, the driving unit includes, as the plurality of optical images, an R optical image corresponding to R color modulated light, a G optical image corresponding to G color modulated light, and a B color modulation. The light modulation element is driven so that a B optical image corresponding to light is emitted in an R period, a G period, and a B period, and the luminance modulation element is used for the R optical image, the G optical image, and the B optical element. The luminance modulation is performed on the image, and the control unit controls the liquid crystal element so as to change the tilt angle of the liquid crystal molecules corresponding to the R period, the G period, and the B period, respectively.
According to this aspect, the tilt angle of the liquid crystal molecules in the vertical alignment type liquid crystal element is set to a highly accurate timing (that is, the R period, the G period, and the B period with respect to the R optical image, the G optical image, and the B optical image). ), The occurrence of lateral chromatic aberration can be more effectively prevented.

In the aspect related to the light modulation element and the luminance modulation element described above, the light modulation element includes a plurality of second pixels including three sub-pixels corresponding to the R optical image, the G optical image, and the B optical image, respectively. The luminance modulation element may have a second modulation area corresponding to each of the second pixels.
With this configuration, the pixel structure of the luminance modulation element is simplified with respect to the pixel structure of the light modulation element, so that the manufacturing cost of the luminance modulation element can be reduced.

Further, in the aspect related to the light modulation element and the luminance modulation element described above, the luminance modulation element may have a modulation area corresponding to each of the sub-pixels as the second modulation area.
If comprised in this way, since a brightness | luminance modulation element has the pixel structure similar to a light modulation element, a brightness | luminance modulation element can be manufactured, without changing the manufacturing process in a light modulation element largely. Therefore, it is not necessary to use an optical element having a special structure for the luminance modulation element, so that an increase in manufacturing cost can be suppressed.

In another aspect of the electro-optical device of the present invention, the relay optical system includes at least one of a magnification adjustment mechanism and a focus adjustment mechanism.
According to this aspect, due to the action of at least one of the magnification adjustment mechanism and the focus adjustment mechanism included in the relay optical system, the optical path in the optical system of the electro-optical device and the positional relationship of each component on the optical axis are slightly shifted. Even if this occurs, an optical image synthesized by the light modulation element can be formed on the luminance modulation element by enlarging or reducing the optical image.

In the aspect related to the relay optical system described above, the focus adjustment mechanism may form the plurality of optical images on the light incident surface of the luminance modulation element.
With this configuration, since the optical image modulated by the light modulation element by the focus adjustment mechanism is incident on the luminance modulation element, incidence of moire can be reduced.

(projector)
In order to solve the above-described problems, a projector according to the present invention includes the above-described electro-optical device according to the present invention (including various aspects), a light source that emits the light, and projection optics that projects the plurality of optical images. And a projector.
According to the projector of the present invention, it is possible to effectively prevent the occurrence of lateral chromatic aberration in the projector of the present invention in substantially the same manner as the electro-optical device of the present invention described above.
Note that the projector of the present invention can appropriately adopt the same aspects as the various aspects of the electro-optical device of the present invention described above.
The operation and other advantages of the present invention will become apparent from the best mode for carrying out the invention described below.

(First embodiment)
(Basic configuration of optical system of electro-optical device)
Next, a basic configuration of the optical system of the electro-optical device according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing the basic configuration of the optical system of the electro-optical device according to this embodiment.

  As shown in FIG. 1, the optical system of the electro-optical device 1 such as a projector includes a device main body 1 </ b> A, a projection lens 4, and a screen S.

The apparatus main body 1A includes a light source unit 10, a reflective liquid crystal light valve 20 for color modulation, a polarization separation element 30 having a wire grid WG1, a dichroic prism 35, a relay lens 40, a vertical alignment liquid crystal panel 50, and a wire grid WG2. And a reflection-type liquid crystal light valve 70 for luminance modulation.
Among these, as shown in FIG. 1, the liquid crystal light valve 20 has red light (hereinafter referred to as “R light”), green light (hereinafter referred to as “G light”), and blue light (hereinafter referred to as “R light”) emitted from the light source 11. Hereinafter, the light valve 20R for R light, the light valve 20G for G light, and the light valve 20B for B light are included. The polarization separation element 30 includes a polarization separation element 30R, a polarization separation element 30G, and a polarization separation element 30B corresponding to the R light, G light, and B light, respectively.

The light source unit 10 includes a light source 11, first and second fly array lenses 13 a and 13 b, and a polarization conversion element 14. The light source 11 emits white light including R light, G light, and B light. The light source 11 includes a high-pressure mercury lamp 11a that emits light, and a reflector (reflecting portion) 11b that reflects the light emitted from the high-pressure mercury lamp 11a. The high-pressure mercury lamp 11a is a lamp that emits white light including red light, green light, and blue light.

The first and second fly array lenses 13a and 13b are lenses that make the illuminance distribution of the light emitted from the high-pressure mercury lamp 11a uniform. The polarization conversion element 14 is a light having a specific polarization direction that can be incident on a uniform liquid crystal light valve 20 for color modulation and a reflective liquid crystal light valve 70 for luminance modulation, which will be described later. It is an element that converts to. In addition, the polarization conversion element 14 is composed of, for example, a PBS array and a half-wave plate, and converts random polarization into specific linear polarization.
The white light emitted from the light source 11 is separated into R light and light including G light and B light in the first / color separation element 9A, and G light is separated in the second / color separation element 9B. Separated into B light.

The reflective liquid crystal light valve 20 for color modulation has a silicon substrate on which reflection pixel electrodes are formed in a matrix and a transparent substrate on which transparent electrodes are formed facing each other via a spacer, and liquid crystal is enclosed between them. Has been. A drive circuit for driving the reflective pixel electrode is also formed on the silicon substrate. An alignment film for aligning liquid crystals in a predetermined direction is formed on the surfaces of these two substrates. When the reflective liquid crystal light valve 20 is driven based on external color data (that is, color information), the arrangement of the liquid crystal molecules changes according to the modulation signal, and the polarization state of the incident light beam changes accordingly.
The light transmitted through the polarization separation element 30 is modulated and reflected in the polarization state by the reflective liquid crystal light valve 20, and among the light beams incident on the polarization separation element 30, for example, S of the S polarization component and P polarization component. The polarized component (that is, the light component that has undergone color modulation) is totally reflected and forms an image on the reflective liquid crystal light valve 70 for luminance modulation through the relay lens 40, the vertical alignment type liquid crystal panel 50, and the polarization separation element 60. Is done.

The polarization separation element 30 includes a wire grid WG1 and includes, for example, a polarization beam splitter (Polarized Beam Splitter: hereinafter referred to as “PBS”) array, a half-wave plate, and the like, and is emitted from a light source. The light beam in the indefinite polarization state is converted into polarized light whose vibration direction is aligned in one direction so that it can be used in the subsequent optical system.
The wire grid WG1 constitutes a specific example of the grid polarizer according to the present invention. FIG. 2 is a plan view schematically showing a wire grid which is a specific example of a grid polarizer provided in the polarization separation element according to the present embodiment (FIG. 2A), and along H1-H1 ′. FIG. 2 is a cross-sectional view (FIG. 2B). Note that the X, Y, and Z axes in FIG. 2 are common. As shown in FIGS. 2A and 2B, the polarization separation element 30 according to this embodiment includes a wire grid 301 and a conductive wire 301a. The wire grid 301 according to the present embodiment may be composed of linear grid-like conductive wires 301a made of a metal such as aluminum, silver, or Cr on a transparent substrate such as glass and arranged in parallel at a constant period. The arrangement period of the conductive wire 301a is set to 0.3 μm or less, the duty ratio of the lattice of the conductive wire 301a is set to 0.1 to 0.3, and the groove depth of the lattice of the conductive wire 301a is set to 0.05 to 0.4 μm. It's okay.

  Such a wire grid 301 reflects a polarization component that holds an electric field vector that oscillates in parallel to the direction along the conductive line 301a of the wire grid 301 when light of random polarization (that is, natural polarization) is incident. The polarized light component that vibrates orthogonally to the direction along the conductive line 301a is transmitted. When light passes through the wire grid 301, linearly polarized light having a polarization direction orthogonal to the direction along the conductive line 301a can be obtained.

  The dichroic prism 35 relays the R light, G light, and B light that are transmitted through the polarization separating element 30 (= 30R, 30G, 30B) and subjected to color modulation by the liquid crystal light valve 20 (= 20R, 20G, 20B). Proceed toward 40.

The relay lens 40 is an equal-magnification imaging lens including a front lens group and a rear lens group that are arranged substantially symmetrically with respect to the aperture stop. The relay lens 40 includes a front lens group and a rear lens group including a plurality of convex lenses and concave lenses. The shape, size, arrangement interval and number of lenses, telecentricity, magnification, and other lens characteristics are as follows. It is appropriately changed according to required characteristics. Based on such a configuration, the relay lens 40 relays the optical image (light) synthesized by the reflection liquid crystal light valve 20 for color modulation to the reflection liquid crystal light valve 70 for luminance modulation. .
In particular, the relay lens 40 includes a magnification adjustment mechanism and a focus adjustment mechanism. Note that the relay lens 40 may include one of a magnification adjustment mechanism and a focus adjustment mechanism. The magnification adjustment mechanism and the focus adjustment mechanism are variously configured by appropriately setting the shape and curvature of the convex lens and the concave lens, for example. With this configuration, even if there is a slight shift in the positional relationship between the components on the optical path and the optical axis in the optical system of the electro-optical device 1, the optical image is enlarged or reduced by the magnification adjustment mechanism. An optical image (light) synthesized by the reflective liquid crystal light valve 20 for modulation can be formed on the reflective liquid crystal light valve 70 for luminance modulation.

  The vertical alignment type liquid crystal panel 50 changes the refractive index when light passes through the liquid crystal panel 50 by changing the tilt angle of the liquid crystal molecules in the liquid crystal layer sealed in the liquid crystal panel 50, and the lateral chromatic aberration. Effectively prevent the occurrence of The details of the vertical alignment type liquid crystal panel 50 will be described later.

  The polarization separation element 60 has substantially the same configuration as the polarization separation element 30 described above, includes a wire grid WG2, and includes, for example, a polarization beam splitter (PBS) array and a half-wave plate. The light beam in the indefinite polarization state emitted from the light source is converted into polarized light whose vibration direction is aligned in one direction so that it can be used in the subsequent optical system.

  The reflection-type liquid crystal light valve 70 for luminance modulation has substantially the same configuration as the reflection-type liquid crystal light valve 20 for color modulation described above, and is transparent to a silicon substrate having reflective pixel electrodes formed in a matrix on the surface. A transparent substrate on which an electrode is formed is disposed oppositely through a spacer, and liquid crystal is sealed therebetween. A drive circuit for driving the reflective pixel electrode is also formed on the silicon substrate. An alignment film for aligning liquid crystals in a predetermined direction is formed on the surfaces of these two substrates. When the reflective liquid crystal light valve 70 is driven based on external luminance data (that is, luminance information), the arrangement of the liquid crystal molecules changes according to the modulation signal, and the polarization state of the incident light beam changes accordingly. The light is modulated and reflected by the reflection-type liquid crystal light valve 70 for luminance modulation, and is reflected by the polarization state. For example, all the S-polarized light components (light components subjected to luminance modulation) are incident on the polarization separation element 60. The light is reflected and projected on the screen S through the projection lens 4.

  In particular, the electro-optical device 1 such as a projector modulates and modulates both color information (or color data) and luminance information (or luminance data) separately and independently to provide a reflective liquid crystal for color modulation. An optical image emitted from the light valve 20 is relayed to the liquid crystal light valve 70 for luminance modulation via the relay lens 40, and an image can be generated by superimposing the luminance modulation. As a result, it is possible to suppress the narrowing of the modulation range when the luminance information is modulated due to the influence of the color modulation of the color information, and the modulation range when the color information is modulated due to the influence of the luminance modulation of the luminance information. It can be suppressed. As a result, an image projected from the electro-optical device 1 such as a projector can be converted into an image quality having a high luminance dynamic range and a high number of gradations.

(Basic configuration of control device for electro-optical device)
Next, a basic configuration of the control device of the electro-optical device according to the present embodiment will be described with reference to FIG. FIG. 3 is a block diagram showing the basic configuration of the control device for the electro-optical device according to this embodiment.

  3, the control device 100 of the electro-optical device according to the present embodiment includes an interface 101, a YC separation circuit 102, a Y processing circuit 103, a C processing circuit 104, drive control circuits 105, 106 and 107, a control circuit 108, and a ROM 109. And a reflective liquid crystal light valve 70 for luminance modulation as a control target, a reflective liquid crystal light valve 20 for color modulation as a control target, and a vertical alignment liquid crystal panel 50 as a control target. Yes. An example of a light modulation element according to the present invention is constituted by a reflective liquid crystal light valve (so-called C modulation element) 20 for color modulation. An example of a luminance modulation element according to the present invention is constituted by a reflection-type liquid crystal light valve (so-called Y modulation element) 70 for luminance modulation. The vertical alignment type liquid crystal panel 50 constitutes an example of a liquid crystal element according to the present invention. The control circuit 108 constitutes an example of control means according to the present invention. The drive control circuit 106 constitutes an example of drive means according to the present invention. The drive control circuits 105, 106, and 107 may be combined into one circuit.

  For example, input video data such as an HDR (High Dynamic Range) video signal is input to the YC separation circuit 102 via the interface 101. In the YC separation circuit 102, for example, a control value (that is, luminance data) for driving and controlling the reflection-type liquid crystal light valve 70 for luminance modulation based on a pixel value (for example, X0) included in the inputted input video data. And a process of calculating a control value (that is, color data) for driving and controlling the reflective liquid crystal light valve 20 for color modulation. The control value of the liquid crystal light valve 70 for luminance modulation calculated by the YC separation circuit 102 is stored in a luminance frame memory in the drive control circuit 105. In addition, the control value of the color modulation liquid crystal light valve 20 is stored in a color frame memory in the drive control circuit 106. Note that the luminance data constitutes an example of luminance information according to the present invention. Further, the color data constitutes an example of color information according to the present invention.

  The drive control circuit 105 supplies a drive signal to the liquid crystal light valve 70 for luminance modulation based on the control value stored in the frame memory. In addition, the drive control circuit 106 supplies a drive signal to the liquid crystal light valve 20 for color modulation based on the control value stored in the frame memory. Thus, by driving the liquid crystal light valve 70 for luminance modulation and the liquid crystal light valve 20 for color modulation, an image including an image having a wide luminance dynamic range can be displayed.

  The control circuit 108 is configured to be able to output a so-called frame switching signal and field switching signal, and has an R cycle Tr for emitting an R optical image, and a G cycle Tg and B for emitting a G optical image. Various control signals for changing the voltage applied to each pixel of the vertical alignment type liquid crystal panel 50 are output corresponding to the B period Tb for emitting an optical image. The detailed operation principle of the control circuit 108 will be described later.

  The ROM 109 stores correction values Dr, Dg, and Db, which are values for correcting the reference value of the applied voltage applied to each pixel of the vertical alignment type liquid crystal panel 50, and is configured to be able to input and output to the control circuit 108. ing. These correction values Dr, Dg, and Db will be described later.

(Transmission type vertical alignment type liquid crystal panel)
Next, the vertical alignment type liquid crystal panel 50 will be described. 4 is an overall configuration diagram of the liquid crystal panel according to the present embodiment (FIG. 4A) and a sectional configuration diagram taken along the line HH ′ of FIG. 4A (FIG. 4B). ). FIG. 5 is an explanatory diagram showing the configuration of the liquid crystal panel according to the present embodiment.
As shown in FIG. 4, the liquid crystal panel 50 includes a counter substrate 51 and a TFT array substrate 52 that are disposed to face each other, and has a configuration in which both are bonded via a seal material 33. A liquid crystal layer 53 is sealed in a region surrounded by the counter substrate 51, the TFT array substrate 52, and the sealing material 33. The liquid crystal layer 53 is made of a liquid crystal having negative dielectric anisotropy, and in the liquid crystal panel 50 of the present embodiment, as shown in FIG. 5, the liquid crystal molecules 53e have a predetermined inclination (between the alignment films 52a and 51b ( The structure is vertically aligned with a pretilt angle.

  The liquid crystal panel 50 includes a liquid crystal layer 53 sealed in a region partitioned by the TFT array substrate 52, the counter substrate 51, and the sealing material 33. In the liquid crystal panel 50, a light shielding film 35 is formed inside the region where the sealing material 33 is formed so as to be part of the periphery. An inter-substrate conducting material 57 for providing electrical continuity between the TFT array substrate 52 and the counter substrate 51 is disposed at a corner on the outer peripheral side of the sealing material 33.

  In the TFT array substrate 52, a data line driving circuit 71, an external circuit mounting terminal 75, and two scanning line driving circuits 73 are formed in a region outside the region where the sealing material 33 is formed in plan view. Further, a plurality of wirings 74 for connecting the scanning line driving circuits 73 provided on both sides of the image display region are also formed in the region of the TFT array substrate 52. Instead of forming the data line driving circuit 71 and the scanning line driving circuit 73 on the TFT array substrate 52, for example, they are formed on the TAB (Tape Automated Bonding) substrate on which the driving LSI is mounted and the peripheral portion of the TFT array substrate 52. The terminal group may be electrically and mechanically connected via an anisotropic conductive film.

  The counter substrate 51 is a microlens substrate (light collecting substrate) having a plurality of microlenses arranged in a plane, as shown in FIG. The counter substrate 51 is mainly composed of a substrate 92, a resin layer 93, and a cover glass 94.

  The substrate 92 and the cover glass 94 are transparent substrates made of glass or the like, and substrates made of quartz, borosilicate glass, soda lime glass (blue plate glass), crown glass (white plate glass), or the like can also be used. A plurality of concave portions (microlenses) 95 are formed on the liquid crystal layer 53 side (the lower surface side in the drawing) of the substrate 92. The microlens 95 collects light incident on the substrate 92 from the side opposite to the liquid crystal layer 53 and emits the light toward the liquid crystal layer 53 side.

  The resin layer 93 is a layer made of a resin material filled on the microlens 95 of the substrate 92, and is formed using a resin material that can transmit light, such as an acrylic resin. The resin layer 93 is provided so as to cover one side of the substrate 92 and fill the concave interior of the microlens 95. The upper surface of the resin layer 93 is a flat surface, and a cover glass 94 is attached to the flat surface.

  A light shielding film 35, a common electrode 97, and an alignment film 51b are formed on the surface of the microlens substrate on the liquid crystal layer 53 side. The light shielding film 35 is formed on the cover glass 94 in a substantially lattice shape in plan view. The microlenses 51 a are located between the light shielding films 35 and are respectively disposed in regions overlapping the pixel region of the liquid crystal panel 50 (region where the pixel electrode 42 is formed) in plan view. The alignment film 51b is a vertical alignment film that aligns liquid crystal molecules constituting the liquid crystal layer 53 substantially perpendicularly to the substrate surface. For example, a silicon oxide film formed with a columnar structure by oblique deposition, It consists of a polyimide film or the like that has been subjected to orientation treatment.

  The TFT array substrate 52 is mainly composed of a transparent substrate 41 made of glass, quartz, or the like, a pixel electrode 42 formed on the side surface of the liquid crystal layer 53 of the substrate 41, a TFT 44 for driving the pixel electrode, and an alignment film 52a. Has been.

The pixel electrodes 42 are conductive films having a substantially rectangular shape in plan view made of a transparent conductive material such as ITO, for example, and are arranged in a matrix in plan view on the substrate 41 as shown in FIG. It is formed in a region overlapping with the microlens 51a.
Although the TFT 44 is simplified in illustration, the TFT 44 is formed on the substrate 41 corresponding to each of the pixel electrodes 42, and is usually a region overlapping with the light shielding film 35 on the counter substrate 51 side (non-display region, It is arranged in the light shielding area.

Similar to the previous alignment film 51b, the alignment film 52a formed so as to cover the pixel electrode 42 is a vertical alignment film made of a silicon oxide film or the like formed by oblique deposition.
The alignment films 52a and 51b are formed so that their alignment directions (alignment directions of the columnar structures) are substantially parallel in a plan view, and the liquid crystal molecules 53e constituting the liquid crystal layer 53 are predetermined with respect to the substrate surface. The liquid crystal molecules function so as to be uniform in the direction of the substrate surface.

  A data line (not shown) and a scanning line (not shown) for connecting the pixel electrode 42 and the TFT 44 are formed in a region on the liquid crystal layer 53 side surface of the substrate 41 that is inside the region where the sealing material 33 is formed in plan view. ) Is formed. The data line and the scanning line are formed in a region overlapping the light shielding film 35 in plan view. A region bordered by the light shielding film 35, the TFT 44, the data line, and the scanning line is a pixel region of the liquid crystal panel 50. A plurality of pixel areas are arranged in a matrix in plan view to form an image display area.

  In particular, as shown in FIG. 5, in the liquid crystal panel 50, the alignment films 52a and 51b opposed to each other with the liquid crystal layer 53 interposed therebetween, for example, deposit silicon oxide from an oblique direction deviated by about 50 ° from the substrate normal direction. Is formed. The film thickness is about 40 nm in all cases. The alignment direction in the alignment film 52a and the alignment direction in the alignment film 51b may be parallel to each other. Then, due to the alignment regulating force of the alignment films 52a and 51b, the liquid crystal molecules 53e are aligned in a state inclined by about 2 ° to 8 ° from the substrate normal, and the director direction of the liquid crystal molecules 53e (pretilt direction P) is the substrate surface. The orientation is such that the direction is along the orientation direction.

The control circuit described above corresponds to the R cycle Tr for emitting the R optical image, the G cycle Tg for emitting the G optical image, and the B cycle Tb for emitting the B optical image. Thus, the voltage applied to each pixel of the vertical alignment type liquid crystal panel 50 is changed. Typically, as will be described later, the periods Tr, Tg, and Tb may be periods obtained by time-dividing one frame period T or one field period into three. Thereby, the tilt angle of the liquid crystal molecules 53e in the liquid crystal layer 53 of the vertical alignment type liquid crystal panel 50 can be changed with respect to each of the R optical image, the G optical image, and the B optical image. Accordingly, when the R optical image, the G optical image, and the B optical image are dispersed when light passes through the wire grid type polarization separation element 30, the R optical image, the G optical image is displayed in the vertical alignment type liquid crystal panel 50. Since the refractive index of each of the optical images B and B can be changed, the occurrence of lateral chromatic aberration can be effectively prevented.
Specifically, the liquid crystal layer 53 sealed in the liquid crystal panel 50 exhibits optically positive uniaxiality, and the refractive index in the director direction 531 of the liquid crystal molecules 53e is larger than the refractive index in other directions. . That is, the liquid crystal layer 53 has a rugby ball type refractive index ellipsoid, as shown in the above-described average refractive index ellipsoid 530 in FIG. Thereby, the tilt angle of the liquid crystal molecule 53e is changed with respect to each of the R optical image, the G optical image, and the B optical image, so that the tilt angle of the refractive index ellipsoid 530 is changed to the R optical image, the G optical image, and the B optical image. Change for each of the images. As a result, in the vertical alignment type liquid crystal panel 50, the refractive indexes of the R optical image, the G optical image, and the B optical image can be changed in a time division manner.

(Operating principle)
Next, the operation principle of the vertical alignment type liquid crystal panel according to the present embodiment will be described with reference to FIGS. FIG. 6 is a flowchart showing the operation principle of the vertical alignment type liquid crystal panel according to this embodiment. FIG. 7 is a table (FIG. 7A) showing the voltage applied to each pixel of the vertical alignment type liquid crystal panel according to the present embodiment and the tilt angle of the liquid crystal molecules corresponding to the voltage, and the tilt of the liquid crystal molecules. It is sectional drawing (FIG.7 (b)) of the liquid crystal layer which showed an example of the corner | angular diagram schematically.

  In FIG. 6, when the operation of the vertical alignment type liquid crystal panel according to the present embodiment is started, first, under the control of the control circuit, whether the period is the R period Tr for emitting the R optical image. It is determined whether or not (step S101). Here, when it is determined that the period is the R period Tr (step S101: Yes), the correction value Dr is applied as a value for correcting the reference value of the applied voltage (step S102). Accordingly, as shown in FIGS. 7A and 7B, in the period Tr, the liquid crystal molecules 53e are tilted at the tilt angle Pr corresponding to the voltage obtained by correcting the reference value of the applied voltage with the correction value Dr. To do.

  On the other hand, as a result of the determination in step S101, if it is determined that the cycle is the cycle Tr for R (step S101: No), G is further used to emit the G optical image under the control of the control circuit. It is determined whether or not it is the period Tg for use (step S103). Here, when it is determined that the period is the period Tg for G (step S103: Yes), the correction value Dg is applied as a value for correcting the reference value of the applied voltage (step S104). Thus, as shown in FIGS. 7A and 7B, in the period Tg, the liquid crystal molecules 53e are tilted at a tilt angle Pg corresponding to the voltage obtained by correcting the reference value of the applied voltage with the correction value Dg. To do.

  On the other hand, if the cycle is not determined to be the G cycle Tg as a result of the determination in step S103 (step S103: No), the cycle is determined to be the B cycle Tb. The correction value Db is applied as the value to be corrected (step S105). As a result, as shown in FIGS. 7A and 7B, in the period Tb, the liquid crystal molecules 53e are tilted at the tilt angle Pb corresponding to the voltage obtained by correcting the reference value of the applied voltage with the correction value Db. To do.

(Examination of action and effect of vertical alignment type liquid crystal panel according to this embodiment)
Next, operations and effects of the vertical alignment type liquid crystal panel according to the present embodiment will be described with reference to FIG. FIG. 8 is a schematic diagram (FIG. 8A) conceptually showing the principle of the occurrence of lateral chromatic aberration in the comparative example, and the action of the vertically aligned liquid crystal panel according to this embodiment and the lateral chromatic aberration. It is the schematic diagram (FIG.8 (b)) which showed the principle which prevents generation | occurrence | production conceptually.
As shown in the comparative example of FIG. 8A, when a wire grid type polarization separation element 30 is used as a polarization optical system such as PBS, for example, it is configured by, for example, a wire grid WG1 having a strip-shaped aluminum portion. When the light is transmitted through the wire grid type polarization separation element 30, variation occurs in the traveling directions of the R light, the G light, and the B light, thereby causing an R optical image, a G optical image, and a B optical image. There is a technical problem that the magnification at which the light is projected varies, and so-called lateral chromatic aberration occurs.
Note that the lateral chromatic aberration or the like is caused by the fact that the left and right optical systems in the figure are not arranged symmetrically as seen from the center line CL of the relay lens 40 shown in FIG.

  On the other hand, according to the present embodiment, as shown in FIG. 8 (b), for example, reflection is performed based on R image data, G image data, and B image data input in a time-division manner within one frame. An R optical image, a G optical image, and a B optical image are emitted from the liquid crystal light valve 20 of the mold every R cycle Tr, G cycle Tg, and B cycle Tb. Typically, the periods Tr, Tg, and Tb may be periods obtained by time-dividing one frame period T or one field period into three.

  In addition to this, the voltage applied to each pixel of the vertical alignment type liquid crystal panel 50 is changed for each of the R optical image, the G optical image, and the B optical image. Thereby, the tilt angle of the liquid crystal molecules 53e in the liquid crystal layer 53 of the vertical alignment type liquid crystal panel 50 can be changed with respect to each of the R optical image, the G optical image, and the B optical image. Thereby, since each refractive index of R optical image, G optical image, and B optical image can be changed, generation | occurrence | production of the magnification chromatic aberration mentioned above can be prevented effectively.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the configuration of the electro-optical device 1 such as a projector is different. FIG. 9 is an external perspective view schematically showing an optical relationship between the reflective liquid crystal light valve for color modulation and the reflective liquid crystal light valve for luminance modulation according to the second embodiment. 9 (a) and 9 (b)). Note that, in the drawings of the embodiments described below, the same reference numerals are given to the same components as those in the first embodiment described above, and descriptions thereof will be omitted or simplified.

  In the first embodiment, a so-called three-plate projector provided with three liquid crystal light valves is used. However, in the second embodiment, one reflective liquid crystal light valve 20 for color modulation is usually used. (The present invention basically corresponds to each of the R optical image, the G optical image, and the B optical image, regardless of the configuration.) Thus, it is only necessary that the applied voltage of the vertical alignment type liquid crystal panel 50 can be changed.

  The optical image 251 generated by the color modulation reflective liquid crystal light valve 20 according to the second embodiment includes a plurality of pixels 252 as shown in FIG. Each pixel 252 includes a plurality of sub-pixels 253R, 253G, and 253B including modulated light of different colors. On the other hand, the reflective liquid crystal light valve 70 for luminance modulation has a luminance modulation region 750, and the luminance modulation region 750 includes a plurality of pixels 755. The pixel 755 corresponds to each pixel 252 of the optical image generated in the reflective liquid crystal light valve 20 for color modulation described above, and brightness modulation is possible in each of them.

  Here, the correspondence between the pixel 252 in the optical image 251 and the pixel 755 in the luminance modulation area 750 means that the modulated light in a certain pixel 252 is superimposed on a predetermined pixel 755. That is, color modulation and luminance modulation can be performed on the light from the light source unit 10 in an overlapping manner. Thus, the pixel structure is simplified by eliminating the sub-pixels in the pixel structure of the luminance modulation region 750 of the reflective liquid crystal light valve 70 for luminance modulation, and the cost of the reflective liquid crystal light valve 70 for luminance modulation is reduced. Yes. That is, it is possible to reduce the cost of the electro-optical device 1 itself.

  Alternatively, as shown in FIG. 9B, the pixel 755 in the luminance modulation region 750 may have the same configuration as the pixel 251 of the reflective liquid crystal light valve 20 for color modulation. That is, the pixel 755 in the luminance modulation region 750 includes three subpixels 755R, 755G, and 755B. Thus, the reflective liquid crystal light valve 70 for luminance modulation can be manufactured without greatly changing the manufacturing process of the reflective liquid crystal light valve 20 for color modulation of the electro-optical device 1. Therefore, it is not necessary to use a liquid crystal display element having a special structure as the reflective liquid crystal light valve 70 for luminance modulation, and an increase in cost can be prevented.

  As described above, the electro-optical device 1 according to the first embodiment can be converted into an image quality having a high luminance dynamic range and a high gradation number.

  In addition, this invention is not limited to embodiment mentioned above, A various change is possible in the range which does not deviate from the meaning of this invention. For example, in the above embodiment, the projector provided with the reflective liquid crystal light valve has been described, but the present invention is also applicable to a projector provided with a transmissive liquid crystal light valve. The present invention can also be applied to a DLP (Digital Light Processing (trademark)) projector.

  Moreover, in said embodiment, although what provided the high pressure mercury lamp 11a and the reflector 11b as the light source 10 was illustrated, this invention is not limited to this. For example, the light source 10 can be replaced with various types of light sources 10 as long as they are conventionally used as illumination devices such as backlights used in liquid crystal devices and organic EL elements.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification, and an electro-optical device with such a change, A projector including the electro-optical device is also included in the technical scope of the present invention.

1 is a block diagram illustrating a basic configuration of an optical system of an electro-optical device according to an embodiment. The top view (Drawing 2 (a)) which showed typically the wire grid which is one specific example of the grid polarizer provided in the polarization splitting device concerning this embodiment, and sectional view along H1-H1 '( FIG. 2 (b)). FIG. 3 is a block diagram illustrating a basic configuration of a control device of the electro-optical device according to the present embodiment. FIG. 4 is an overall configuration diagram (FIG. 4A) of the liquid crystal panel according to the present embodiment and a sectional configuration diagram (FIG. 4B) along the line H-H ′ in FIG. 4A. It is explanatory drawing which shows the structure of the liquid crystal panel which concerns on this embodiment. It is a flowchart which shows the operation | movement principle of the vertical alignment type liquid crystal panel which concerns on this embodiment. A table (FIG. 7A) showing the voltage applied to each pixel of the vertical alignment type liquid crystal panel according to the present embodiment and the tilt angle of the liquid crystal molecules corresponding to the voltage, and an example of the tilt angle of the liquid crystal molecules It is sectional drawing (FIG.7 (b)) of the liquid crystal layer shown schematically. A schematic diagram conceptually showing the principle of occurrence of lateral chromatic aberration in the comparative example (FIG. 8A), and the principle of preventing the action of the vertical alignment type liquid crystal panel according to this embodiment and the occurrence of lateral chromatic aberration. FIG. 9 is a schematic diagram (FIG. 8B) schematically shown. FIG. 9A and FIG. 9B are perspective views schematically showing the optical relationship between a reflective liquid crystal light valve for color modulation and a reflective liquid crystal light valve for luminance modulation according to the second embodiment. 9 (b)).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electro-optical apparatus, 1A ... Apparatus main body, 4 ... Projection lens, 10 ... Light source part, 20 ... Reflection type liquid crystal light valve for color modulation, 30 ... Polarization separation element, 40 ... Relay lens, 50 ... Vertical alignment type Liquid crystal panel, 60 ... Polarization separation element, 70 ... Reflective liquid crystal light valve for luminance modulation, 100 ... Control device of electro-optical device, 101 ... Interface, 102 ... YC separation circuit, 103 ... Y processing circuit, 104 ... C processing Circuits 105, 106 and 107 ... drive control circuit 108 ... control circuit 109 ... ROM, S ... screen, WG1, WG2 ... wire grid.

Claims (10)

A light modulation element for modulating light from the light source;
A signal separation unit for separating input image information into color information and luminance information;
Driving means for driving the light modulation element so as to emit a plurality of optical images respectively corresponding to a plurality of color modulated lights at a plurality of predetermined periods based on the color information;
A luminance modulation element for performing luminance modulation on the plurality of optical images based on the luminance information;
A relay optical system that relays the plurality of optical images between the light modulation element and the luminance modulation element;
A polarization optical system including a grid polarizer and changing a polarization state of the plurality of optical images;
A vertical alignment type liquid crystal composed of liquid crystal molecules vertically aligned by the alignment film is sandwiched between a pair of substrates each having an alignment film, and the plurality of optical images can be obtained by tilting the liquid crystal molecules. A liquid crystal element that can be refracted,
An electro-optical device comprising: control means for controlling the liquid crystal element so as to change the tilt angle of the liquid crystal molecules at one of the plurality of predetermined periods. The drive means drives the light modulation element to emit a plurality of time-divided optical images at the plurality of predetermined periods,
The luminance modulation element performs the luminance modulation on the plurality of time-divided optical images,
2. The electro-optical device according to claim 1, wherein the control unit controls the liquid crystal element so as to change an inclination angle of the liquid crystal molecule corresponding to each of the plurality of time-divided optical images. .   The liquid crystal element has a first pixel region in which a plurality of first pixels are arranged, and changes a tilt angle of the liquid crystal molecules by changing a voltage applied to each first pixel. The electro-optical device according to claim 1 or 2, characterized in that   4. The electro-optical device according to claim 1, wherein each of the light modulation element and the luminance modulation element includes a reflective liquid crystal light valve. 5. The driving means includes, as the plurality of optical images, an R optical image corresponding to R color modulated light, a G optical image corresponding to G color modulated light, and a B optical image corresponding to B color modulated light, an R period, Driving the light modulation element to emit in the G period and the B period,
The luminance modulation element performs the luminance modulation on the R optical image, the G optical image, and the B optical image,
5. The control device according to claim 1, wherein the control unit controls the liquid crystal element so as to change an inclination angle of the liquid crystal molecules corresponding to the R cycle, the G cycle, and the B cycle. The electro-optical device according to any one of the above. The light modulation element has a second pixel region in which a plurality of second pixels including three sub-pixels corresponding to the R optical image, the G optical image, and the B optical image are arranged, and
The electro-optical device according to claim 5, wherein the luminance modulation element has a second modulation region corresponding to each of the second pixels.   The electro-optical device according to claim 6, wherein the luminance modulation element has a modulation area corresponding to each of the sub-pixels as the second modulation area.   The electro-optical device according to claim 1, wherein the relay optical system includes at least one of a magnification adjustment mechanism and a focus adjustment mechanism.   The electro-optical device according to claim 8, wherein the focus adjustment mechanism forms the plurality of optical images on a light incident surface of the luminance modulation element. The electro-optical device according to any one of claims 1 to 9,
A light source that emits the light;
A projector comprising: a projection optical system that projects the plurality of optical images.

Images