JP2000137202A - Projection display device - Google Patents

Abstract

(57) Abstract: In a projection display device, color unevenness caused by variations in contrast and brightness in a plurality of image components caused by azimuth dependence of optical characteristics of a liquid crystal panel is reduced. SOLUTION: Optical compensation layers 51 and 52 are arranged on both front and back sides of a liquid crystal panel 10 composed of transparent substrates 11 and 12 and a liquid crystal layer sealed therebetween, and two polarizing plates 5 are provided outside the optical compensation layers.
When the light emitted from the light source 55 is transmitted upward in FIG.
And the optical azimuth dependency is greatly reduced as compared with the case where only the polarizing plates 53 and 54 are used. Therefore, when combining image components in the projection display device, even if mirror inversion between image components occurs, color unevenness of the combined image is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device, and more particularly, to a method of forming a plurality of image components by using a plurality of liquid crystal panels and synthesizing the plurality of image components to obtain a desired image.
For example, the present invention relates to a configuration of a display device configured to project as a color image.

[0002]

2. Description of the Related Art Conventionally, in a projection type display device using a liquid crystal panel as a light valve, for example, a liquid crystal projector, light of three primary colors of red, blue, and green is generally passed through different liquid crystal panels, respectively, to obtain respective colors. Each image component is formed, and these image components are combined to create a desired color image, which is projected forward.

In the case of synthesizing the three color image components, a cubic dichroic prism is used, and two liquid crystal panels are arranged adjacent to each other on two side surfaces and the front surface of the four outer peripheral surfaces of the dichroic prism. By irradiating three colors of light to the liquid crystal panel,
By introducing two of the three color image components from the side of the dichroic prism and selectively reflecting them, and introducing the remaining one color image component from the front and transmitting it, a composite image is formed from the back of the dichroic prism. There is one configured to inject.

As a liquid crystal panel used in the above liquid crystal projector, a TN type active matrix panel is generally used. This liquid crystal panel is formed in a matrix shape by enclosing a TN type liquid crystal layer between two panel substrates and arranging two polarizing plates having light transmission axes orthogonal to each other outside the panel substrate. The light transmission state is changed by applying an electric field to each of the pixels.
An active element such as a TFT (thin film transistor) element or a TFD (Thin Film Diode) is formed on one side of the panel substrate so that a desired image signal can be selectively applied to each pixel electrode.

[0005]

In the above liquid crystal projector, of the image components modulated by the liquid crystal panel, the image component reflected by the selective reflection surface in the dichroic prism and the image component transmitted through the dichroic prism are transmitted. The image components are combined with each other in a mirror-inverted state. At this time, since a plurality of liquid crystal panels installed in the liquid crystal projector are usually the same, if the optical characteristics of the liquid crystal panels have azimuth dependence, image components of different colors mirror-inverted to each other are synthesized. Then, there is a problem that color unevenness may occur in the original image to be reproduced.

Normally, in a projection type display device such as a liquid crystal projector, unlike a general liquid crystal display panel, the viewing angle dependency itself, such as a limited viewing angle range with good visibility, is almost always included in a reproduced image. Has no effect,
The liquid crystal panel has not only the viewing angle itself but also the azimuth dependence of the optical characteristics, that is, the characteristic that the contrast and the brightness change depending on the azimuth angle of the line of sight. In-plane distribution peculiar to this occurs. For example, a TN type liquid crystal has a clear viewing direction determined by a rubbing direction and a twisting direction of liquid crystal molecules, and when viewed from the clear viewing direction, in a region where the viewing angle is low, not to mention other directions. The contrast is higher than in the direction normal to the panel surface. In particular, when the clear viewing direction is shifted from the direction of the mirror inversion axis of the mirror inversion of the image component, the mirror inversion reverses the direction corresponding to the clear viewing direction in the image component, which causes color unevenness in the composite image. .

Accordingly, the present invention has been made to solve the above problems, and the problem is caused by the azimuth dependence of the optical characteristics of a liquid crystal panel in a projection display device.
An object of the present invention is to reduce color unevenness caused by variations in contrast and brightness in a plurality of image components.

[0008]

According to a first aspect of the present invention, there is provided a liquid crystal display comprising a plurality of liquid crystal panels, and combining a plurality of image components light-modulated by each liquid crystal panel. In a projection display device configured to project a composite image, the contrast or brightness deviation of the in-image distribution of the image components is reduced by an optical compensation layer provided corresponding to the liquid crystal panel. It is characterized by having. By reducing the azimuth dependence of the optical characteristics of the liquid crystal panel by using the optical compensation layer, by reducing the bias of the contrast or brightness of the image distribution of the image component,
Without depending on the optical system when combining image components,
For example, even if mirror inversion or rotation occurs between image components during image synthesis, color unevenness of the synthesized image can be reduced without changing the optical characteristics of the liquid crystal panel itself.

In the first aspect, it is preferable that the same optical compensation layer is used for a plurality of liquid crystal panels. By using the same optical compensation layer for a plurality of liquid crystal panels, the manufacturing cost can be reduced and the optical characteristics of each liquid crystal panel can be made uniform.

[0010] In the first or second aspect, it is preferable that at least one image component is combined with another image component in a mirror-inverted state. When a plurality of image components are combined with each other being mirror-inverted, even if the distribution of the optical bias of the plurality of image components has the same tendency, the difference in the bias of the image components is emphasized by the mirror inversion. Therefore, it is particularly effective to reduce the azimuth dependence of the optical characteristics of the liquid crystal panel by the optical compensation layer.

In the third aspect, the image component is a plurality of color lights for forming a color image, and the plurality of image components respectively transmitted through the plurality of liquid crystal panels are incident on color combining optical means, The image component is composed of an image component that is reflected an odd number of times and an image component that is reflected an even number of times, wherein the image component projects light synthesized by the color synthesizing unit through a projection optical unit. I do. For example, three types of basic color images for forming a color image, and the image components transmitted through the three liquid crystal panels, respectively, are output from three of the four outer peripheral surfaces of a color synthesizing unit such as a dichroic prism. Incident, two of the image components are reflected, one of the image components is transmitted,
In some cases, the composite image is configured to be projected from another surface of the outer periphery of the dichroic prism. In such a case, even if the image component is inverted even-number inverted and odd-number inverted, the color unevenness of the synthesized image can be reduced without changing the optical characteristics of the liquid crystal panel itself.

In each of the above means, the optical compensation layer may be a negative uniaxial substance having an optical axis inclined in a direction corresponding to the azimuth dependence of the optical characteristics of the liquid crystal panel. preferable. For example, it is preferable that the optic axis of the discotic liquid crystal is tilted in a predetermined direction by an alignment process in order to favorably compensate the azimuth dependency of the liquid crystal panel. Further, the optical compensation layer is preferably disposed between the polarizing plate and the panel substrate in the TN type liquid crystal panel, and particularly preferably disposed outside the two panel substrates.

[0013] In any one of the first to fourth aspects, it is preferable that the optical compensation layer is attached to the liquid crystal panel. By adhering to the liquid crystal panel, attachment to the projection display device is facilitated, and the size of the device can be reduced. In this case, when a polarizing plate is provided on the liquid crystal panel, it is desirable to attach an optical compensation layer together with the polarizing plate.

[0014] In any one of the first to fourth aspects, it is desirable that the optical compensation layer and the liquid crystal panel are spaced apart from each other. By disposing the optical compensation layer and the liquid crystal panel apart from each other, heat dissipation can be improved, and the influence on the image quality due to the defect of the optical compensation layer and the adhesion of dust can be reduced by the defocus effect. In this case, when a polarizing plate is provided on the liquid crystal panel, it is preferable that the polarizing plate is also spaced apart from the liquid crystal panel. In that case, both the optical compensation layer and the polarizing plate may be attached to a color combining means such as a dichroic prism. Further, if the polarizing plate and the optical compensation layer are also separated from each other, it is possible to suppress an increase in heat of the polarizing plate and the optical compensation layer.

Next, as a second means adopted by the present invention, a plurality of liquid crystal panels are provided, and a composite image formed by combining a plurality of image components light-modulated by each liquid crystal panel is projected. A projection type wherein at least one of the image components is combined with another of the image components in a mirror-inverted state with respect to an axis of symmetry extending in a direction different from the clear viewing direction of the liquid crystal panel. In the display device, the liquid crystal panel that forms one of the image components and the liquid crystal panel that forms another of the image components are mirrored with each other with respect to the same symmetric axis as the mirror inversion of the image components. It is characterized by being configured in an inverted state.

The liquid crystal panel that forms one image component and the liquid crystal panel that forms another image component have their clear viewing directions symmetrical to the mirror inversion between the one image component and the other image component. By being configured to be mirror-inverted with respect to the axis, when one image component and another image component are synthesized in a mirror-inverted state with respect to each other, each component of the synthesized image is shifted in the clear vision direction. Since the corresponding image distribution bias is provided in the same direction, it is possible to reduce color unevenness of the composite image.

In a preferred embodiment, the mirror inversion relationship between the liquid crystal panels in the clear viewing direction is formed by a difference in a rubbing direction of a panel substrate constituting the liquid crystal panel and / or a twist direction of the liquid crystal. . At least one of the rubbing directions of the two panel substrates,
Alternatively, the clear viewing direction can be changed by changing the twist direction of the liquid crystal in the liquid crystal layer. In this case, the rubbing directions of the two panel substrates may be changed together, or the rubbing direction and the twist direction of the liquid crystal may both be changed.

The rubbing direction of the liquid crystal panel with respect to one panel substrate may be the same direction along one type of wiring on the surface of the panel substrate, and the rubbing direction of the liquid crystal panel with respect to the other panel substrate may be reversed. It is preferable that the direction of clear vision between the liquid crystal panels be mirror-reversed by setting the direction and the twist direction of the liquid crystal to the opposite direction. In particular, in the case of a TFT liquid crystal panel using a TN liquid crystal, by setting a rubbing direction in a direction of a certain wiring on an element substrate having a TFT element, the influence of a rubbing defect due to a step on an inner surface of the substrate is reduced. In this case, the clear viewing direction can be reversed by changing the rubbing direction of the opposing substrate and the twisting direction of the liquid crystal without changing the rubbing direction for the element substrate having a large step.

Further, the third means adopted by the present invention comprises a plurality of liquid crystal panels, and is configured to project a composite image formed by composing a plurality of image components light-modulated by each liquid crystal panel. In the projection display device, the liquid crystal panel applies an image signal line and an image signal selected from the image signal line to an inner surface of one of two panel substrates sandwiching a liquid crystal layer. A pixel electrode, and a counter electrode formed in parallel with an interval between the pixel electrodes, and a counter electrode to which a counter potential is applied, and the panel substrate generated between the pixel electrode and the counter electrode. The liquid crystal layer is configured to control the light transmittance of the liquid crystal layer by changing an orientation direction in the liquid crystal layer mainly in a plane parallel to a panel surface by an electric field including a parallel electric field component. I do.

A liquid crystal panel for forming an image component in the device generates an electric field component parallel to the panel surface by a pixel electrode and a counter electrode formed on one of the panel substrates, and the electric field changes the orientation of the liquid crystal by the electric field. Since the light transmittance is controlled by changing the light transmittance in a plane parallel to the panel surface, it is possible to reduce the azimuth dependence of the optical characteristics generated by the inclination of the optical axis of the liquid crystal molecules, Therefore, it is possible to reduce the color unevenness of the synthesized image that occurs due to the azimuth dependency when the image components are synthesized.

In the tenth aspect, it is preferable that the liquid crystal layer in the liquid crystal layer has a predetermined state in which the orientation direction in a plane parallel to the panel surface varies. Even when the display is realized by changing the orientation direction of the liquid crystal in a plane parallel to the panel surface, if the orientation directions of the liquid crystal are aligned in a plane parallel to the panel surface before and after the change, the alignment is performed. If the azimuth angle is different based on the azimuth angle of the direction, the visibility will be different, so that the orientation direction of the liquid crystal molecules varies in a plane parallel to the panel surface in this state, depending on the azimuth dependence of the optical characteristics This is preferable for further reducing the properties. As a method of dispersing the alignment direction of liquid crystal molecules in this way, there is a method of forming a multi-domain by divided alignment or the like.
As a method of forming a multi-domain, as will be described later, there are a method of forming regions having different alignment treatments, a method of forming an inclined surface on an inner surface facing a liquid crystal, and the like.

A fourth means according to the present invention is a projection type comprising a plurality of liquid crystal panels, and configured to project a composite image formed by combining a plurality of image components light-modulated by each liquid crystal panel. In the display device, the liquid crystal panel has a first alignment state in which liquid crystal molecules in a liquid crystal layer in the liquid crystal panel are aligned in a direction substantially perpendicular to the panel surface, and the liquid crystal molecules are inclined with respect to the panel surface. The display mode is characterized by changing the display mode by making a transition between a second orientation state in which the display state is oriented or substantially parallel. In this manner, by forming a so-called vertical alignment type liquid crystal panel, the azimuth dependency of the optical characteristics at the time of vertical alignment of the liquid crystal molecules is reduced, and the synthesis generated due to the azimuth dependency at the time of synthesizing the image components. Color unevenness of an image can be reduced.

In the twelfth aspect, in the first alignment state, the liquid crystal molecules in the liquid crystal layer are configured to be slightly inclined with respect to the panel surface, and the directions of the slight inclination are varied. Is preferred. In the first alignment state, the liquid crystal molecules that are aligned almost vertically are slightly tilted to control the tilt when the liquid crystal molecules transition to the second alignment state or the azimuth that is aligned parallel to the panel surface. Can also be
The azimuth of the liquid crystal molecules in the second alignment state or the azimuth of the liquid crystal molecules when the liquid crystal molecules are aligned in parallel is varied by configuring the liquid crystal panel such that the slightly inclined direction varies, thereby reducing the azimuth dependence of the optical characteristics in the liquid crystal panel. be able to.

Still further, a fifth means according to the present invention comprises a plurality of liquid crystal panels, and is configured to project a composite image formed by combining a plurality of image components light-modulated by each liquid crystal panel. In the projection type display device described above, the liquid crystal panel has a divided alignment structure (multi-domain structure) including a plurality of alignment regions having different alignment directions of liquid crystal molecules.

By providing a liquid crystal panel having a divided orientation structure in which the orientation directions of liquid crystal molecules are different, the azimuth dependence of the optical characteristics of the liquid crystal panel can be appropriately designed. It is possible to reduce color unevenness of a composite image generated due to the nature.

In this case, the azimuth dependence of the optical characteristics of the liquid crystal panel can be appropriately designed by the divided orientation structure. For example, one image component among a plurality of image components formed by a plurality of liquid crystal panels can be used. In the case of a projection display device in which the image component and other image components are combined in a mirror-inverted state with respect to a certain axis of symmetry, the azimuth dependence of the optical characteristics of the liquid crystal panel forming these image components is symmetric. If the split orientation structure is designed to be symmetrical with respect to the axis, the occurrence of color unevenness due to mirror inversion can be reduced. Therefore, in this case, it is not always necessary to reduce the azimuth dependence of the optical characteristics of the liquid crystal panel over all azimuth angles.

In the fourteenth aspect, it is preferable that the divided alignment structure is provided so as to reduce the azimuth dependence of the optical characteristics of the liquid crystal panel and to make it uniform. In this case, since the divided orientation structure is provided so as to reduce the azimuth dependency itself, the occurrence of color unevenness in the synthesized image is suppressed regardless of the image synthesis mode (for example, the direction of the symmetry axis at the time of mirror inversion). Can be suppressed.

According to claim 14 or 15, as the alignment region, a region subjected to different rubbing treatment is provided, an alignment film having optical alignment characteristics capable of controlling an alignment state by light irradiation, a liquid crystal layer is used. Is formed by providing a plurality of inclined surfaces inclined in different directions on the inner surface of the panel substrate facing the substrate.

Any one of claims 7 to 15
In the above item, it is preferable that an optical compensation layer for alleviating the azimuth dependence of the optical characteristics of the liquid crystal panel is disposed in the optical path. In the above-mentioned second to fifth means, it is effective to further arrange an optical compensation layer to reduce the azimuth dependency of the liquid crystal panel. Although it is difficult to sufficiently and effectively reduce the azimuth dependence of the optical characteristics only by the structure in the liquid crystal panel, a sufficient effect can be easily obtained by combining with the optical compensation layer. .
In this case, there are a case where the optical compensation layer is attached to and integrated with the liquid crystal panel and a case where the optical compensation layer is separated from the liquid crystal panel.

Any one of claims 1 to 16
In the above item, it is preferable that the rubbing direction of the liquid crystal panel is performed in a direction along at least one kind of wiring direction in a panel substrate constituting the liquid crystal panel. By performing the rubbing direction of the liquid crystal panel in the direction along the wiring direction, it is possible to prevent poor alignment due to wiring steps. In this case, there is a case where a clear viewing direction occurs in the left and right diagonal directions of the liquid crystal panel by aligning the liquid crystal in the wiring direction. Therefore, even in a projection display device that combines image components that are mirror-inverted to the left and right, since the above-described units can reduce color unevenness in the combined image, the display quality can be improved by performing orientation processing in the wiring direction. The above means of the present invention are particularly effective.

[0031]

Next, an embodiment according to the present invention will be described with reference to the accompanying drawings.

[Overall Configuration of Projection Display Device] First,
The overall configuration of the projection display device according to the present embodiment will be described. FIG. 1 shows a structure of an optical system of a liquid crystal projector which is a projection display device.

The housing of the liquid crystal projector 20 incorporates an optical unit shown in a sectional view in the drawing. The optical unit includes an illumination optical system including a light source and light sources for emitting red, green, and blue light. A color separation optical system for separating into R, G, B, a color synthesis optical system for re-synthesizing each color light R, G, B after passing through each liquid crystal light valve described later; A light guide system for guiding colored light to the system.

The illumination optical system includes a light source lamp 21 and an integrator lens 22 composed of an aggregate of minute lenses.
23, a polarization conversion element 24 composed of an aggregate of a polarization separation film and a quarter-wave plate, and a reflection mirror 25 are provided. As a light source lamp, a halogen lamp, a metal halide lamp, a xenon lamp, or the like can be used.
The polarization conversion element 24 has a structure in which a built-in light transmission plate is in contact with a quarter-wave plate in a state where a polarization separation film inclined with respect to the optical axis is arranged. The P-polarized light transmitted through the separation film and reflected by the polarization separation film is reflected by another adjacent polarization separation film and converted into S-polarized light, so that the incident light can be aligned with S-polarized light.

The color separation optical system is provided with a red-green reflection dichroic mirror 26 and a green reflection dichroic mirror 28. The red and green reflection dichroic mirror 26 reflects the color lights R and G, and transmits the color light B. Of the reflected color lights R and G, the color light G is reflected by the green reflection dichroic mirror 28, and the color light R passes through the green reflection dichroic mirror 28.

In the light guide system, the color light B is reflected by the reflection mirror 2.
The light is reflected at 7 and enters the condenser lens 35. The color light G is directly condensed from the green reflection dichroic mirror 27 to the condenser lens 3.
4 is incident. The color light R is incident on the condenser lens 33 via the incident side lens 29, the reflection mirror 30, the intermediate lens 31, and the reflection mirror 32.

Liquid crystal light valves 36, 37, 38 are attached to the ends of the condenser lenses 33, 34, 35, respectively. These liquid crystal light valves are constituted by a liquid crystal panel module in which a liquid crystal panel to be described later is housed in a panel mounting frame and wiring members such as a flexible wiring board are connected, and a panel mounting frame to be described later is supported and fixed in an optical unit. It is installed by inserting and fixing to 39. Switching of these light valves is controlled by control driving means (not shown) (conductively connected to the wiring member) according to desired image information, and modulates the respective color lights R, G, and B.

In the color synthesizing optical system, each of the color lights R, G, and B modulated by the liquid crystal light valves 36, 37, and 38 to form a predetermined image component is converted into three colors.
A cubic prism unit 40 constituting a dichroic prism received on one surface is provided. The prism unit 40 combines the respective color lights R, G, and B to form a color image including desired image information. This color image is projected onto projection optical means (projection lens unit) 4.
1, the image is enlarged and projected on a screen (not shown) at a predetermined position.

In such a liquid crystal projector 20, when FIG. 1 shows a cross section of the apparatus, of the image components modulated and formed by the liquid crystal light valves 36, 37 and 38, the liquid crystal light valve The image components formed by 36 and 38 are reflected by the selective reflection surface in the prism unit 40, but the liquid crystal light valve 37
The image component formed by the above is transmitted through the prism unit 40 without being reflected. Therefore, the image component formed based on the color lights R and B and the image component formed based on the color light G are combined in a mirror-reversed manner with the vertical axis as a symmetric axis in the left-right direction, and are combined forward. Will be projected. In other words, the plurality of image components transmitted through the plurality of liquid crystal panels respectively include an image component that is incident on the prism unit and is reflected oddly and an image component that is reflected even number of times, and these image components synthesized by the prism unit are combined. Is a configuration in which the light is projected through the projection optical means.

[Structure of Liquid Crystal Panel] As shown in FIGS. 2 and 3, the liquid crystal panel 10 constituting the liquid crystal light valves 36, 37 and 38 includes a transparent substrate 11 (element substrate) made of glass or the like and a transparent substrate. 12 (opposite substrate) are adhered so as to have a predetermined gap (cell gap) via a sealing material 14, and a liquid crystal 13 is injected into a liquid crystal sealing region 10 a formed inside the sealing material 14. Have been. The liquid crystal 13 is injected from a liquid crystal injection port 14a provided in the sealant 14, and the liquid crystal injection port 14a is thereafter closed by a sealing agent 15 made of resin or the like. As the sealing material 14, an epoxy resin or various photocurable resins can be used. To secure the cell gap, a particle size (about 2 to 10 μm) corresponding to the cell gap is formed in the sealing material 14.
Incorporate an inorganic or organic fiber or sphere with m).

The transparent substrate 11 has a surface area slightly larger than that of the transparent substrate 12, and active elements such as wiring layers, transparent electrodes, and TFTs (thin film transistors) are formed on the inner surface thereof corresponding to a large number of pixels. A wiring layer and a transparent electrode corresponding to the pixel are also formed on the inner surface of the transparent substrate 12. Outside the pixel corresponding area on the inner surface of the transparent substrate 12,
A light-shielding film 12 a formed in a circular shape is formed inside the formation region of the sealant 14.

The sealing material 1 on the inner surface of the transparent substrate 11
The wiring pattern 1 electrically connected to the wiring layers formed on the inner surfaces of the transparent substrates 11 and 12
1a is formed, and a scanning line driving circuit 17 and a data line driving circuit 18 composed of an integrated circuit chip or the like are mounted in accordance with the wiring pattern 11a. Further, an outer edge portion on one side of the transparent substrate 11 is formed with an external terminal portion 11b in which a large number of external terminals 19 are arranged.
A wiring member such as a flexible wiring board 16 is conductively connected to 1b via an anisotropic conductive film or the like.

The liquid crystal 13 has a TN type, an STN type, and an IP.
S (in-plain switching) mode, VA (vertically a
A liquid crystal panel suitable for a liquid crystal panel of various modes such as a ligned mode can be used. In the liquid crystal panel 10, a polarizing film, a retardation film, a polarizing plate, and the like can be mounted in a predetermined direction according to the type of the liquid crystal 13 used, the operation mode, the display mode (normally white, normally black), and the like. .

FIG. 4 shows a transparent substrate 11 for forming an active matrix type liquid crystal panel using TFTs.
5 shows an equivalent circuit diagram on an (element substrate or active matrix substrate), FIG. 5 shows an enlarged plan view of the same transparent substrate 11, and FIG. 6 shows a view along the line VI-VI in FIG. 1 schematically shows a cross-sectional structure cut by cutting. As shown in FIG. 4, a scanning line 101 and a data line 103 are formed on an element substrate so as to be vertically and horizontally parallel to each other. The scanning line 101 is connected to a gate of a TFT 104 formed for each pixel.
The source of the TFT 104 is connected to the data line 103. The drain of the TFT 104 is electrically connected to the pixel electrode 106 and also to the storage capacitor 105. The storage capacitor 105 is connected to the capacitance line 102. As a method of forming the storage capacitor 105, the storage capacitor 105 may be connected to the preceding scanning line 101 instead of the capacitor line 102.

A scanning signal Gn is pulse-wise applied to the scanning line 101 in a line-sequential manner, and an image signal Sn is applied to the data line 103.
Is applied line-sequentially, or is applied for each group of a plurality of adjacent data lines. TF
In T104, a potential corresponding to the data signal Sn is appropriately written to the pixel electrode 106 according to the scanning signal Gn. The pixel electrode 106 is opposed to a counter electrode (not shown) formed on the inner surface of the transparent substrate 12 via a liquid crystal layer (not shown), and applies a desired electric field to the liquid crystal layer between the pixel electrode 106 and a counter electrode to which a predetermined potential is supplied. .

As shown in FIG. 5 and FIG.
5 extends in a region shown by oblique lines in FIG. 5, the source 1041 is conductively connected to the data line 103 through the opening 1041a, and the gate 1042 crosses the scanning line 101 via a thin insulating film (not shown). opposite. The drain 1043 is conductively connected to the pixel electrode 106 through the opening 1043a. The lower electrode 1040 extending from these structures overlaps the capacitor line 102 in a plane via an insulating layer, and forms the storage capacitor 105. As is well known, the storage capacitor 105 is for maintaining the potential of the pixel electrode 106 for a long time against electric charge leakage.

[Relationship Between Alignment Treatment and Clear Viewing Direction (Second Means)] FIG. 7 shows the relationship between the rubbing direction of the TN type active matrix type liquid crystal panel and the clear viewing direction. is there. In FIG. 7, the liquid crystal panel 10
2 shows a state in which the transparent substrate 11 and the transparent substrate 12 are viewed from the emission side. The vertical and horizontal outline lines in the figure are
In order to show the extending direction of the scanning lines and the data lines on the transparent substrate 11, a wiring structure (or a pixel arrangement structure) is schematically shown.

In a general liquid crystal projector, since the projected image is set to be horizontally long, the liquid crystal panel is installed in the apparatus with the left-right direction being the longitudinal direction as shown in FIG. In the liquid crystal panel 10 described above, an alignment film made of polyimide or the like is formed on the inner surfaces of the transparent substrate 11 (element substrate) and the transparent substrate 12 (counter substrate), and rubbing is performed by rubbing the surface of the alignment film with a cloth or the like. Perform processing. However, the rubbing treatment is performed on the surface of a normal insulating film without forming an alignment film used only for alignment, or using an inorganic film other than an organic film, oblique evaporation of an inorganic material, or the like. In some cases, a mechanical rubbing treatment is not required by forming a coating film using.

Usually, the rubbing process is performed on the transparent substrate 11 in the rubbing direction R (11) from the lower right to the upper left in the figure, and the rubbing direction R from the upper right to the lower left in the figure is processed on the transparent substrate 12. A rubbing process is performed in 12), and the 90-degree twist direction of the liquid crystal is set to the S direction shown in the figure, so that the clear viewing direction of the liquid crystal panel is upward in the figure. The clear viewing direction is determined by the rubbing directions of the transparent substrates 11 and 12 and the twist direction of the liquid crystal. When the rubbing process is performed obliquely with respect to the wiring direction as shown in the drawing, the clear viewing direction can be one of up, down, left and right. Direction.

As shown in FIG. 7, when the clear viewing direction of the liquid crystal panel is upward and the liquid crystal panel is installed in the liquid crystal projector 20 of FIG. 1 as the liquid crystal light valves 36, 37, and 38 in the posture shown in FIG. Since the image component of the color light G among the three image components is only mirror-reversed in the left and right direction with respect to the image components of the color light R and B, the clear visual direction in the three image components is maintained even after the synthesis. Both are upward, and the clear viewing direction does not differ depending on the image component.

On the other hand, as shown by the dotted line in FIG. 7, the rubbing direction of the transparent
By changing the rubbing direction to the direction shown by, and setting the twisting direction of the liquid crystal to the AS direction shown in the figure, the clear viewing direction becomes the right side in the figure. In this case, if the image component of the color light G is mirror-inverted left and right with respect to the other image components as described above, the clear viewing direction is also reversed left and right, and color unevenness occurs in the composite image.

As described above, when the rubbing direction is performed obliquely with respect to the wiring direction (for example, at 45 degrees), the clear viewing direction can be set up and down, and a normal liquid crystal display panel can be used. It is used as it is. But,
In this case, the presence of a step in the wiring (scanning line or data line) may cause poor alignment, which is not preferable in improving display quality. In particular, since a liquid crystal panel used for a projection display device such as a liquid crystal projector needs to form a high-definition pixel structure within a smaller panel area than normal, alignment defects due to wiring steps are likely to occur. There is a problem. Therefore, in this embodiment,
By performing the rubbing direction along the wiring direction, the occurrence of poor orientation due to the wiring step is reduced.

FIG. 8 shows a situation where the rubbing process is performed along the wiring direction. When the rubbing direction R (11) of the transparent substrate 11 is a direction from the bottom to the top in the figure, the rubbing direction R (12) of the transparent substrate 12 is a direction from the right to the left in the figure, and the twist direction of the liquid crystal is the S direction, The clear viewing direction is the upper right direction as shown. As described above, when the rubbing direction is set to the wiring direction, the clear viewing direction is always oblique to the wiring direction. Therefore, if the liquid crystal light valve shown in FIG. 1 is directly installed in the liquid crystal projector in the posture shown in FIG. 8, the image component based on the color lights R and B and the image component based on the color light G are combined in a mirror-reversed state. Therefore, in the composite image, the clear viewing direction of the color components of the color lights R and B and the clear viewing direction of the color component of the color light G are reversed left and right (obliquely upper right and upper left), so that color unevenness occurs. .

Therefore, as one solution to constitute the second means of the present invention, the liquid crystal panel 10 is formed by the rubbing directions R (11) and R (12) and the twist direction S shown by solid lines in FIG. And only the transparent substrate 12 is processed in the rubbing direction AR (12) shown by a dotted line in FIG. 8 opposite to the rubbing direction R (12), and the twist direction of the liquid crystal is shown in FIG.
One in the S direction is prepared, and either one of them is incorporated in the liquid crystal light valves 36 and 38 shown in FIG. By doing so, the rubbing direction of the transparent substrate 12 is set to R (12)
When the twist direction of the liquid crystal is set to the S direction, the upper right of the drawing becomes the clear viewing direction, and the rubbing direction of the transparent substrate 12 is set to AR.
(12) In the case where the twist direction of the liquid crystal is set to the AS direction, the upper left (indicated by a dotted line) in the drawing is the clear viewing direction. Therefore, the clear viewing direction in the synthesized image after the image components are synthesized by mirror inversion of the image components. And the occurrence of color unevenness can be suppressed.

In particular, in the above method, the rubbing direction of the transparent substrate 12 (opposite substrate) and the twist direction of the liquid crystal are changed without changing the rubbing direction R (11) of the transparent substrate 11 (element substrate). Changing direction. This is because the wiring and the like are stacked on the transparent substrate 11, and therefore, the level difference is larger than that of the transparent substrate 12, and poor alignment is likely to occur due to the wiring level difference. Therefore, if the rubbing direction of the transparent substrate 11 is fixed in a direction that suppresses the untreated alignment, and the rubbing direction of the transparent substrate 12 and the twist direction of the liquid crystal are appropriately changed, the occurrence of the untreated alignment can be suppressed as much as possible.
In this embodiment, rubbing is performed in the direction in which the data line 103 extends (upward in the figure) in order to suppress the occurrence of unprocessed alignment. Further, as shown in FIG. 5, the step portion of the scanning line may be designed so as to be alleviated by the capacitance line or the like, and the unaligned region due to the step is hidden by the capacitance line or the light shielding film.

Of course, if it is sufficient to change the clear viewing direction without considering the existing design as described above, two types of liquid crystal panels can be constructed by making the rubbing directions of the transparent substrates 11 and 12 opposite. So you can
It is possible to minimize an increase in cost when a kind of panel is flowed during the manufacturing process. However, in this case, it is difficult to enjoy the advantage of performing the rubbing process in the wiring direction as described above.

FIG. 9 shows that the rubbing directions AR (11) and AR (1) are changed by changing the rubbing directions of the transparent substrates 11 and 12 when the rubbing process is performed in an oblique direction as shown in FIG.
2) shows an example in which the clear viewing direction is changed without changing the twist direction S of the liquid crystal. FIG. 10 corresponds to FIG.
In the case where the rubbing process is performed in the wiring direction as described above, the rubbing directions of both the transparent substrates 11 and 12 are changed to the rubbing directions AR (11) and AR (12), and the liquid crystal twist direction S is not changed and is clearly seen. It shows an example in the case of changing the direction.

Note that the rubbing direction of the transparent substrate 11 is reversed with respect to the initial state of FIG.
In the case of the direction, the clear viewing direction is the lower right direction in the figure,
In the case of a liquid crystal projector configuration in which the relationship between a plurality of image components is mirror-inverted up and down when the image components are combined, similarly, inconsistency in the clear viewing direction due to mirror inversion can be avoided.

[Arrangement of Optical Compensation Layer (First Means)] Next, when a liquid crystal light valve incorporating the liquid crystal panel 10 is installed in the liquid crystal projector 20, the image component in the clear viewing direction due to mirror inversion of the image component is set. As a method of solving the inconsistency, a solution constituting the first means of the present application will be described. In this solution, three liquid crystal light valves 3
6, 37 and 38 are provided with optical compensation layers respectively.

As described above, the reason why the clear viewing direction occurs in the liquid crystal panel is that the liquid crystal molecules having the refractive index anisotropy are twisted by 90 degrees in the TN type liquid crystal cell. The liquid crystal molecules in this state are oriented so that the liquid crystal molecules rise in a direction perpendicular to the substrate when an electric field is applied (in a normally white mode, in a light blocking state).
As shown in FIG. 11A, the alignment direction is slightly inclined with respect to the complete vertical direction. Since the tilt of the liquid crystal molecules in the vertical alignment state causes an optical difference between the tilted direction of the liquid crystal molecules and the other directions, a predetermined viewing angle in the liquid crystal panel (the viewing direction relative to the normal to the panel substrate). (Tilt angle). Therefore, by forming an optical compensation layer that acts to cancel the optical azimuth dependence caused by the tilt in the vertical alignment state of the liquid crystal molecules, it is possible to eliminate the influence of the clear viewing direction of the liquid crystal panel 10.

As shown in FIG. 11A, the liquid crystal panel 10
By disposing the optical compensation layers 51 and 52 on both sides of the liquid crystal panel, the azimuth dependence of the optical characteristics of the liquid crystal panel 10 is canceled out or reduced. Therefore, the optical compensation layer 5
By disposing the liquid crystal light valves 1 and 52 in all of the liquid crystal light valves 36, 37 and 38, the optical orientation of the liquid crystal panel can be obtained even if the image components formed by the liquid crystal light valves are combined in a mirror-inverted state. Since the dependency is reduced, the bias of the image component itself is reduced,
Therefore, color unevenness in the composite image is also suppressed.

As shown in FIG. 11A, in order to compensate the viewing angle of the positively uniaxial liquid crystal having a simple inclination, a negative uniaxial substance having a simple inclination opposite to the positive uniaxial may be used. Negative uniaxiality means that n1 <n2 to n3 (n2
And n3 need not be exactly equal, but need only be approximately equal. And the characteristic that the refractive index in the optical axis direction is the smallest. Specifically, abs
If [n2-n3] / abs [n2-n1] (abs indicates an absolute value) is 0.2 or less, there is no practical problem. Further, in order to perform the optical compensation of the TN type liquid crystal cell well, the optical axis of the negative uniaxial substance is inclined with respect to the optical axis (normal to the panel surface) for the above-mentioned reason (tilt of liquid crystal molecules). Just do it. The viewing angle characteristics can be improved by the retardation plate exhibiting such negative uniaxiality and having its optical axis inclined.

As the optical compensation layer or the optical compensation film, various materials can be considered as long as the above requirements are satisfied.
In particular, as shown in FIG. 11B, it is preferable that the liquid crystal layer in the liquid crystal panel 10 corresponds to a more precise alignment state of liquid crystal molecules. In the liquid crystal layer, the liquid crystal molecules in the liquid crystal layer are vertically aligned. Strictly speaking, the liquid crystal molecules existing in the middle part of the liquid crystal layer are almost vertically aligned. Therefore, it is necessary to optimize the structure of the optical compensation layers 51 and 52 to have a higher-order structure like the structure of the liquid crystal layer.

As the above-mentioned optical compensation layer constituting such a higher-order structure, a layer in which the optical axis of a discotic liquid crystal is inclined by an alignment treatment can be used. Various known alignment techniques can be used for the alignment treatment. For example, an alignment film made of polyimide or the like is formed on a base film, rubbed, and then discotic liquid crystal (diluted with a solvent). ) Is applied and oriented, and then polymerized and cured by drying or baking. As the base film, a film having a high light transmittance is preferable, and a film formed of a material having a small intrinsic birefringence and plane-oriented is preferable. Japanese Patent Application Laid-Open No. 49-1070 discloses a discotic liquid crystal coating method.
No. 40, JP-A-56-133067, and the like, a method of applying the composition at an inclination angle of 0 to 9 degrees using a slide coater is preferable.

As the discotic liquid crystal, any liquid crystal can be used as long as it has the above-mentioned negative uniaxiality and is capable of tilt alignment. In particular, there are benzene derivatives, cyclohexane derivatives, There are azacrown-based and phenylacetylene-based macrocycles, which generally have a structure in which these are used as a mother nucleus and linear alkyl groups, alkoxy groups, substituted benzoyloxy groups, and the like are radially substituted. In addition, a low-molecular discotic liquid crystal having a high molecular weight by crosslinking is also included.

The tilt angle of the discotic liquid crystal with respect to the panel normal line due to the above alignment is about 5 to 50 degrees, particularly preferably 10 to 40 degrees, and more preferably 25 to 35 degrees. Further, when the thickness of the optical compensation layer, which is an optically anisotropic element, is d, it is preferable that Δn ′ · d (nm) is 50 or more and 400 or less. Here, Δn ′ =
(N2 + n3) / 2-n1. Further, as shown in the figure, by disposing the optical compensation layers on both the front and back sides of the liquid crystal layer, characteristics having no particular azimuth dependence can be obtained.

FIG. 12 is a graph showing the distribution of the contrast with respect to the viewing angle and the azimuth angle in the TN type liquid crystal panel in which the clear viewing direction is set downward in the drawing. Here, the radius of the concentric circle in the graph indicates a range of a viewing angle of 10 to 60 degrees, and the orbital direction indicates an azimuth of 0 to 360 degrees. Numerical values 10, 20, 50, and 100 showing the curves in the graph indicate the values of the contrast ratio at the viewing angle and the azimuth.
Although the contrast distribution originally has a large azimuth dependence in the vertical direction as shown in FIG. 12A, the use of the optical compensation layer (film) makes it extremely uniform as shown in FIG. It is compensated to have the azimuth characteristic.

Here, as the azimuth dependence of the optical characteristics of the liquid crystal panel used in the projection display device, the range of the viewing angle from about 0 to 15 degrees is particularly important, and the viewing angle exceeds 15 degrees. The characteristics of the region hardly contribute to the display characteristics. Therefore, in the present invention, including all embodiments described in this specification, the viewing angle is set to 0.
It is sufficient that the azimuth dependency is improved within the range of up to 15 degrees. Similarly, since a plurality of liquid crystal panels are used after mirror inversion as described above, the azimuth dependency only needs to be corrected substantially symmetrically with respect to the mirror inversion symmetry axis.

FIGS. 15 and 16 show the optical arrangement when the above-described optical compensation layer is used. FIG.
Reference numeral 5 denotes an obliquely-aligned liquid crystal panel subjected to the rubbing treatment shown in FIG. 7, and FIG. 16 employs an alignment treatment in the wiring direction subjected to the rubbing treatment shown in FIG. In each case, optical compensation layers 51 and 52 are arranged on both front and back sides of a liquid crystal panel 10 composed of transparent substrates 11 and 12 and a liquid crystal layer sealed therebetween, and two polarizing plates 53 and
By arranging 54, when the light emitted from light source 55 is transmitted upward in the drawing, the azimuth dependency of the optical characteristics is greatly reduced as compared with the case where only liquid crystal panel 10 and polarizing plates 53 and 54 are provided. Is done.

In FIGS. 15 and 16, the optical compensation layer 5
Arrows 1 and 52 indicate the orientation directions R (51) and R (52) of the negative uniaxial substance due to the orientation treatment, respectively. Thus, the optical compensation layers 51, 52
By placing (or. In only one or the other) inside the <br/> polarizing plate crossed nicols, the liquid crystal panel 10
Since the azimuth dependence of the optical characteristics of the liquid crystal is reduced, by disposing an optical compensation layer in each liquid crystal light valve of the liquid crystal projector shown in FIG. 1, color unevenness of a composite image due to mirror inversion of each image component is suppressed. You.

Here, the optical compensation layer may be formed as an independent film or sheet, may be formed on a substrate film as described above, or may be formed on a surface of a panel substrate or a polarizing plate. It may be formed.
In addition, the optical compensation layer or the optical compensation film may be attached to the liquid crystal panel together with the polarizing plate, may be attached to the surface of the prism unit, or may be independently disposed between the liquid crystal panel and the prism unit. May be. in this case,
In a projection type display device, by disposing an optical compensation layer (film) and a polarizing plate slightly apart from each other with respect to a liquid crystal panel, a heat radiation effect can be enhanced. There is an advantage that even if there are various defects or dust adheres to the surface, they hardly affect the image quality due to the defocusing action.

According to this method, the azimuthal dependence of the optical characteristics of the liquid crystal panel is reduced by the optical compensation layer, so that the color unevenness of the synthesized image can be easily reduced without any change in the liquid crystal panel itself. Be able to
Since it is not necessary to provide different configurations for the plurality of liquid crystal light valves, it is possible to eliminate the trouble of process management and to produce the liquid crystal light valves more easily.

[IPS Mode Liquid Crystal Panel (Third Means)] Next, the contents relating to the third means described in the present application will be described. As a method of suppressing color unevenness due to mirror inversion at the time of combining image components, it is conceivable to reduce the azimuth dependence of the optical characteristics of the liquid crystal panel itself. In this method, by making the panel structure inherently small in azimuth dependence of optical characteristics,
It is not necessary to manufacture a plurality of types of liquid crystal panels or to prepare an optical compensator.

FIGS. 17 and 18 show the liquid crystal panel 1 shown in FIG.
7 shows an enlarged planar structure and a cross-sectional structure of a liquid crystal panel 60 that can be used instead of 0. This liquid crystal panel 60
A nematic liquid crystal is arranged between the element substrate 61 and the counter substrate 62, and the pixel electrodes 6 formed on the element substrate 61 together.
5 and a counter electrode 67, a predetermined electric field is generated in the liquid crystal layer to generate an electric field component in a direction parallel to the panel surface, and the electric field causes the liquid crystal molecules to be oriented in a direction parallel to the panel surface. Changing the optical state by changing the IP
It is a liquid crystal panel of S (in-plain switching) mode.

In the liquid crystal panel 60, as shown in FIG. 17, a scanning line 63 extending in the horizontal direction in the figure and a data line 64 extending in the vertical direction in the figure are formed on the surface of the element substrate 61. The data line 64 has an extension 64a for each pixel, and a TFT (thin film transistor) 6 is formed at a position directly above the scanning line 63 via a gate insulating film 63a formed over the entire surface as shown in FIG.
8 is connected. The TFT 68 is connected to an end of the pixel electrode 65 which faces the extension 64 a via a channel region controlled by a gate electrode (not shown). The pixel electrode 65 has a comb-shaped (a figure having only two teeth) planar shape extending in a U-shape in the pixel region.

On the other hand, an opposing line 66 is formed extending in the left-right direction of FIG. 17, and this opposing line 66 supplies a common potential to each pixel arranged in parallel in the vertical and horizontal directions. The opposing lines 66 are integrally formed with three opposing electrodes 67 protruding in a comb-tooth shape for each pixel region. An anodic oxide film 67a (see FIG. 18) is formed over the entire surface of the opposing line 66 and the opposing electrode 67 (formed by anodic oxidation of aluminum if the wiring and electrode material is Al). Insulation between the pixel electrode 65 and the data line 64 is ensured. Further, an alignment film 69a is formed on the surface of the structure shown in FIG. 17 via a transparent insulating film. Note that the storage capacitor Cg shown in FIG. 17 is formed between the pixel electrode and the opposing line in order to keep video information long.

On the inner surface of the counter substrate 62, a black matrix layer 62a having an opening indicated by a chain line in FIG.
Are formed, and the scanning line 63, the data line 64, and the opposing line 66 are formed.
The wiring area consisting of is hidden. On the black matrix layer 62a, an alignment film 69b similar to the above is formed via a transparent insulating film.

In this liquid crystal panel, the liquid crystal panel 6
By providing a polarizing plate in a crossed Nicols arrangement on the front and back of 0, applying a scanning signal to the scanning line 63, applying an image signal to the data line 64, and applying an appropriate opposing potential to the opposing line 66, An image can be formed.

In this embodiment, as shown in (a-1) and (a-2) of FIG. 20, the liquid crystal molecules are oriented almost parallel to the panel surface. Since the orientation direction rotates in a parallel plane, the azimuth dependence of the optical characteristics is small. Therefore, when used as a liquid crystal light valve in the above-described liquid crystal projector, it is possible to suppress color unevenness of a composite image even if mirror inversion of an image component occurs.

However, in this embodiment, as shown in (a-1) and (a-2) of FIG. 20, the directions of the liquid crystal molecules arranged in the panel plane are almost uniform in any alignment state. As a result, the azimuth dependence of the optical characteristics is not completely eliminated due to the angular relationship with the alignment direction of the liquid crystal molecules. FIG. 13A is a graph showing the contrast characteristic of this embodiment. Although the azimuth dependence is remarkably improved as compared with a normal TN type liquid crystal panel, the symmetry of the contrast curve is still broken,
When used in a projection display device, there is room for color unevenness to occur due to mirror inversion. Therefore, in the present embodiment, it is preferable to further improve this embodiment to use the optical compensation layer as described above, or to improve the azimuth dependency by multi-domain. For example, FIG.
The pixel electrode 65 and the counter electrode 6 arranged in parallel as shown in FIG.
7 is changed from a linear shape to a "-" shape, and the arrangement directions of liquid crystal molecules are different within one dot.
One domain can be formed. In this case, in both the states (a-1) and (a-2) of FIG. 20, liquid crystal molecules in a plane parallel to the panel surface but having different alignment directions are present in the dots. Therefore, as shown in FIG. 13B, the symmetry in the azimuth dependence of the optical characteristics is significantly improved.

[Liquid Crystal Panel with Vertical Alignment Structure (Fourth Means)] Next, referring to (b-1) and (b-2) of FIG. 20, a liquid crystal of a VA (vertical aligned) mode with a vertical alignment structure will be described. An embodiment using a panel will be described. By forming the vertical alignment film on the inner surface of the panel substrate, the alignment direction of the liquid crystal molecules in the electroless state (initial state) is set almost perpendicular to the panel surface as shown in FIG. be able to. However, even if it is almost perpendicular, it is sufficient if the inclination angle with respect to the perpendicular is 70 degrees or more. When a predetermined electric field is applied here, the liquid crystal molecules are turned over as shown in FIG.

In the liquid crystal panel having the vertical alignment structure, the liquid crystal molecules are in a posture substantially perpendicular to or substantially parallel to the panel surface. The orientation dependency is improved. FIG. 14A shows the azimuth dependence of the optical characteristics of the liquid crystal panel having the vertical alignment structure. The azimuth dependence of this embodiment is particularly the view angle 1 required for a projection display device.
Characteristics within 5 degrees are relatively good.

However, also in this embodiment, FIG.
Strictly speaking, as shown in (a), since the azimuth dependence symmetry is broken, a certain degree of color unevenness can be avoided in a projection display device combining a plurality of mirror-inverted liquid crystal panels. Absent. Therefore, in order to compensate for this slight loss of orientation-dependent symmetry, it is possible to cope with the above-described optical compensation layer (film) or multi-domain configuration. FIGS. 20 (c-1) and (c-2) show a structure in which a multi-domain is formed in this embodiment. In this structure, a plurality of inclined surfaces are formed on the inner surface of the panel substrate in contact with the liquid crystal layer in order to determine the orientation direction of the liquid crystal in the state where the electric field is applied, since the direction of inclination of the liquid crystal molecules having a slight inclination in the state where no electric field is applied In this way, a plurality of domains are formed by controlling the tilt direction of the liquid crystal when no electric field is applied, thereby improving the symmetry of the optical characteristics. For example, 1
By forming a substantially quadrangular pyramid-shaped projection having four inclined surfaces in a dot, a domain having liquid crystal molecules inclined in four different directions can be formed in one dot.

FIG. 14B shows the optical characteristics (contrast characteristics) of a liquid crystal panel having a vertical alignment structure when four domains are formed in one dot as described above. In this case, the azimuth dependence is obtained symmetrically in the vertical and horizontal directions, and color unevenness does not occur even when used in a projection display device.

[Liquid Crystal Panel with Divided Orientation (Multi-Domain) Structure (Fifth Means)] Finally, a method for reducing the azimuth dependence of optical characteristics by using a liquid crystal panel structure different from the above will be described. The liquid crystal panel formed by this method has a so-called split orientation panel structure,
For example, control is performed by changing the direction of the alignment process performed on the inner surface of the panel substrate between adjacent pixels or within the pixel, or changing the state of the alignment process of the alignment film to change the pretilt angle of the liquid crystal molecules of the two substrates. The orientation direction to be performed is partially changed, or a plurality of inclined surfaces as described above are formed on the surface of the orientation film to provide regions in different orientation states. By employing such a split orientation panel structure, the azimuth dependence of the optical characteristics of the liquid crystal panel is reduced, and the color unevenness of the composite image in the projection display device is reduced.

In this embodiment, a manufacturing method suitable for a small liquid crystal panel built in a projection display device such as a liquid crystal projector will be described with reference to FIG. In order to form a divided alignment panel structure in a high-definition liquid crystal panel, rubbing treatment performed by contact with a rubbing roller or a buff has many problems. Therefore, it is preferable to perform a photo-alignment treatment performed by irradiating the alignment film with ultraviolet light or the like. As the photo-alignment treatment, for example, an alignment film material such as an organic polymer is applied on the surface of the panel substrate 71 and then baked to form an alignment film 72.
Pre-processing exposure for adjusting physical properties of the substrate. In this preprocessing exposure, for example, as shown in FIG. 15A, the surface of the panel substrate 71 is irradiated with ultraviolet rays 73 polarized in a direction perpendicular to the plane of the paper, almost perpendicularly. Next, FIG.
As shown in (1), the alignment film 72 on the surface of the panel substrate is selectively irradiated with ultraviolet light 74 using a predetermined optical mask. The ultraviolet light 74 is polarized in a direction (horizontal direction in the figure) rotated by 90 degrees with respect to the polarization direction of the ultraviolet light in the pretreatment. The ultraviolet light 74 is oblique (for example, 45 degrees) from a direction inclined in a predetermined direction with respect to the panel surface of the panel substrate 71.
Degree) irradiate. Next, an ultraviolet light 75 is applied to the surface area of the remaining alignment film 72 in the exposure area shown in FIG. 15B using an optical mask different from the above-described optical mask. The ultraviolet light 75 is polarized in the same direction as the ultraviolet light 74, but as shown in FIG. 15C, the azimuth angle (for example, the reverse direction) different from that of the ultraviolet light 74 is oblique (for example, 45 degrees). ) Irradiate. When the liquid crystal panel 70 is formed by performing the ultraviolet exposure in this manner and the counter substrate 77 having the alignment film 78 similarly processed, as shown in FIG. 15D, the pretilt angle rising in the irradiation direction of the ultraviolet light Is set, and the liquid crystal molecules are oriented in the same direction as the pretilt angle, and the alignment regions 79a and 79b in which the liquid crystal molecules are oriented in different directions are formed. Here, as the organic material having photo-alignment property, for example, PVCi
(Manufactured by Aldrich) and s610 (manufactured by Nissan Chemical Industries) can be used.

Although other methods for forming the divided alignment structure are not described in detail, they affect the image quality regardless of the alignment treatment method (rubbing, ultraviolet irradiation, ion irradiation, surface shape adjustment). It suffices that a plurality of domains having different alignment states of the liquid crystal molecules are formed as a result in a non-existent range (for example, within a dot).

The liquid crystal panel 70 having the split alignment structure
Can form alignment regions oriented toward two or more different azimuth angles, and as a result, for example, to reduce the bias of image components due to the clear viewing direction as shown in FIGS. 7 and 8. Therefore, similarly to the above, it is possible to reduce color unevenness in the composite image of the projection display device.

In the liquid crystal panel 70 provided with the above-mentioned divided alignment structure, it has been described that the divided alignment structure is configured to make the azimuth dependence of the optical characteristics of the liquid crystal panel uniform in all directions. In the liquid crystal projector 20 shown in FIG. 1, if the optical characteristics of the liquid crystal panel are symmetrical, color unevenness of the composite image does not matter. Therefore, in the liquid crystal projector, the split orientation structure is set so that the azimuth dependency of the optical characteristic which is almost symmetrical with respect to the mirror inversion axis is obtained so that no problem is caused by the mirror inversion between the image components. It is sufficient if configured. In the above-described embodiment, the transmission type liquid crystal panel using the transparent substrate (element substrate) 11 and the transparent substrate 12 has been described. However, a reflection type liquid crystal panel in which the element substrate 11 is formed of a silicon substrate or the like is used. The present invention is also applicable to a projection type display device.

[0090]

As described above, according to the present invention, the liquid crystal can be obtained by arranging the optical compensation layer, changing the alignment direction to reverse the clear viewing direction, or changing the structure of the liquid crystal panel. By reducing the azimuth dependence of the optical characteristics of the panel and reducing the bias of the image distribution of the image components, the optical characteristics of the liquid crystal panel itself can be changed without depending on the optical system when combining the image components. The color unevenness of the composite image can be reduced without the need.

[Brief description of the drawings]

FIG. 1 is a schematic plan partial cross-sectional view showing a structure of an optical system of a liquid crystal projector as an embodiment of a projection display device according to the invention.

FIG. 2 is a schematic plan view showing a planar structure of a liquid crystal panel incorporated in the embodiment.

FIG. 3 is a schematic cross-sectional view showing a cross-sectional structure of a liquid crystal panel incorporated in the embodiment.

FIG. 4 is an equivalent circuit diagram showing an equivalent circuit of the structure on the element substrate of the liquid crystal panel in the same embodiment.

FIG. 5 is an enlarged plan view showing an enlarged plan view of the structure of the liquid crystal panel on the element substrate in the embodiment.

FIG. 6 is a schematic cross-sectional view showing an enlarged cross section (a state cut along the line VI-VI of FIG. 5) of the structure on the element substrate of the liquid crystal panel in the same embodiment.

FIG. 7 is an explanatory diagram showing a relationship between a rubbing direction set in an oblique direction of the liquid crystal panel and a clear viewing direction.

FIG. 8 is an explanatory diagram showing a relationship between a rubbing direction set in a wiring direction of the liquid crystal panel and a clear viewing direction.

9 is an explanatory diagram showing a case where the clear viewing direction is changed only in the rubbing direction of both panel substrates as in the case shown in FIG.

FIG. 10 is an explanatory diagram showing a case where the clear viewing direction is changed only in the rubbing direction of both panel substrates as in the case of FIG.

FIGS. 11A and 11B are explanatory diagrams illustrating a basic compensation principle of the optical compensation layer in the same embodiment.

FIG. 12 is a graph (a) showing a relationship between a viewing angle and an azimuth angle and a contrast in a conventional TN type liquid crystal panel, and a viewing angle and a view for showing an effect of an optical compensation layer in the liquid crystal panel of the same embodiment. It is a graph (b) which shows the relationship between an azimuth and contrast.

FIG. 13 is a graph (a) showing a relationship between a viewing angle and an azimuth angle and contrast in an IPS mode liquid crystal panel;
6B is a graph (b) showing the relationship between the viewing angle and the azimuth angle and the contrast in a case where two alignment regions are formed in the dots of the IPS mode liquid crystal panel to form a multi-domain.

FIG. 14 is a graph (a) showing a relationship between a viewing angle and an azimuth angle and contrast in a VA mode liquid crystal panel, and four domains formed in dots of the VA mode liquid crystal panel to form a multi-domain. 6B is a graph (b) showing a relationship between a viewing angle and an azimuth angle of the object and contrast.

FIG. 15 is an optical layout diagram showing an arrangement when a liquid crystal panel formed by oblique rubbing in the same embodiment is used together with an optical compensation layer.

FIG. 16 is an optical layout diagram showing an arrangement in a case where a liquid crystal panel formed by a wiring direction rubbing process in the same embodiment is used together with an optical compensation layer.

FIG. 17 shows an IP as a liquid crystal panel in the embodiment.
FIG. 3 is an enlarged plan layout view on an element substrate for illustrating a structure of an S-mode liquid crystal panel.

18 is an enlarged cross-sectional view (showing a state cut along line IV-IV in FIG. 13) showing the structure of the IPS mode liquid crystal panel.

FIGS. 19A to 19D are schematic schematic process diagrams (a) to (d) showing a method and structure for manufacturing a liquid crystal panel having a divided alignment structure as a liquid crystal panel in the same embodiment.

FIGS. 20A and 20B are schematic diagrams (a-1) and (a-2) illustrating a switching state of a display of a liquid crystal panel in an IPS mode, and schematic diagrams (b) illustrating a switching state of a display of a VA mode liquid crystal panel;
-1) and (b-2), and schematic diagrams (c-1) and (c-2) showing a display switching state when a VA mode liquid crystal panel is multi-domain.

[Explanation of symbols]

10, 60, 70 Liquid crystal panel 11, 61, 71 Transparent substrate (element substrate) 12, 62, 77 Transparent substrate (opposing substrate) 20 Liquid crystal projector 36, 37, 38 Liquid crystal light valve 40 Prism unit (dichroic prism) 51, 52 Optical compensation layer R (11), R (12), AR (11), AR (12)
Rubbing direction R (51), R (52) Alignment direction S, AS Twist direction of liquid crystal

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H088 EA14 EA15 HA01 HA03 HA05 HA08 HA13 HA16 HA18 HA24 JA05 MA04 MA05 MA20 2H091 FA05Z FA08X FA08Z FA11X FA11Z FA26X FA26Z GA01 GA06 GA13 HA07 LA11 LA15 LA20 MA07

Claims (17)

[Claims] 1. A projection display device comprising a plurality of liquid crystal panels and configured to project a combined image obtained by combining a plurality of image components light-modulated by the respective liquid crystal panels, wherein an image in the image component is provided. A projection-type display device, wherein bias in contrast or brightness of in-plane distribution is reduced by an optical compensation layer provided corresponding to the liquid crystal panel. 2. The projection display according to claim 1, wherein the same optical compensation layer is used for a plurality of liquid crystal panels. 3. The projection type according to claim 1, wherein at least one of the image components is combined with another of the image components in a mirror-inverted state. Display device. 4. The image processing device according to claim 3, wherein the image components are a plurality of color lights for forming a color image, and the plurality of image components respectively transmitted through the plurality of liquid crystal panels are incident on color combining optical means. The image component is composed of an image component that is reflected an odd number of times and an image component that is reflected an even number of times, and the image component projects light combined by the color combining unit via projection optical unit. Characteristic projection display device. 5. The method according to claim 1, wherein:
In any one of the above items, the optical compensation layer is attached to the liquid crystal panel. 6. One of claims 1 to 4
9. The projection type display device according to item 1, wherein the optical compensation layer is spaced apart from the liquid crystal panel. 7. A liquid crystal panel comprising a plurality of liquid crystal panels, wherein the liquid crystal panel is configured to project a composite image formed by combining a plurality of image components light-modulated by each liquid crystal panel, wherein at least one of the image components is the other of the image components. A projection type display device configured to be combined in a mirror-reversed state with respect to a symmetry axis extending in a direction different from the clear viewing direction of the liquid crystal panel with respect to the component, wherein the one image component is formed. The liquid crystal panel and the liquid crystal panel forming the other image components are configured such that the clear visual directions are mirror-inverted with respect to the same symmetry axis as the mirror inversion of the image components. Projection display device. 8. The liquid crystal display according to claim 7, wherein the mirror inversion relationship between the liquid crystal panels in the clear viewing direction is formed by a difference in a rubbing direction of a panel substrate constituting the liquid crystal panel and / or a twist direction of the liquid crystal. A projection type display device characterized by the above-mentioned. 9. The rubbing direction according to claim 8, wherein the rubbing direction of the liquid crystal panel with respect to one panel substrate is the same direction along one kind of wiring on the surface of the panel substrate, and the rubbing direction of the liquid crystal panel with respect to the other panel substrate. A reverse direction, and a reverse direction of the twist of the liquid crystal, whereby the clear viewing direction between the liquid crystal panels is mirror-reversed. 10. A projection display device comprising a plurality of liquid crystal panels and configured to project a composite image obtained by combining a plurality of image components light-modulated by the respective liquid crystal panels, wherein the liquid crystal panel comprises: An image signal line, a pixel electrode to which an image signal selected from the image signal line is applied, and a gap between the pixel electrode are formed on the inner surface of one of the two panel substrates sandwiching the liquid crystal layer. And a counter electrode to which a counter potential is applied. The liquid crystal layer is formed by an electric field including an electric field component parallel to the panel substrate and generated between the pixel electrode and the counter electrode. A projection-type display device, wherein the liquid crystal layer is configured to control a light transmittance of the liquid crystal layer by changing an alignment direction in the liquid crystal layer mainly in a plane parallel to a panel surface. 11. The projection type display device according to claim 10, wherein the liquid crystal molecules in the liquid crystal layer are arranged so that the alignment direction in a plane parallel to the panel surface in a predetermined state varies. 12. A projection type display device comprising a plurality of liquid crystal panels and configured to project a composite image formed by combining a plurality of image components light-modulated by the respective liquid crystal panels, wherein the liquid crystal panel comprises: A first alignment state in which liquid crystal molecules in a liquid crystal layer in the liquid crystal panel are aligned in a direction substantially perpendicular to the panel surface, and a liquid crystal molecule in which the liquid crystal molecules are inclined with respect to the panel surface or aligned in a substantially parallel direction. A projection type display device configured to change a display mode by transitioning to the second alignment state. 13. The liquid crystal display device according to claim 12, wherein the liquid crystal molecules in the liquid crystal layer are slightly inclined with respect to a panel surface in the first alignment state, and the directions of the slight inclination are varied. A projection-type display device, comprising: 14. A projection display device comprising a plurality of liquid crystal panels and configured to project a combined image obtained by combining a plurality of image components light-modulated by the respective liquid crystal panels, wherein the liquid crystal panel comprises: A projection display device having a divided alignment structure including a plurality of alignment regions having different alignment directions of liquid crystal molecules. 15. The projection type display device according to claim 14, wherein the divided alignment structure is provided so as to reduce the azimuth dependence of the optical characteristics of the liquid crystal panel and make it uniform. 16. A projection type display according to claim 7, wherein an optical compensation layer for reducing azimuth dependence of optical characteristics of said liquid crystal panel is arranged in an optical path. apparatus. 17. The liquid crystal panel according to claim 1, wherein the rubbing direction of the liquid crystal panel is in a direction along at least one type of wiring direction in a panel substrate constituting the liquid crystal panel. Projection type display device characterized by the above-mentioned.