JPH11249141A - Liquid crystal display device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a homeotropic type liquid crystal display(LCD) device and manufacture thereof with which the LCD device with high responsiveness and lightness over wide fields of view can be produced with high yield without the process of rubbing processing. SOLUTION: This device is provided with display electrodes 13a and 13b, vertical orienting films 15a and 15b, liquid crystal layer 16 provided between a pair of substrates 11 and 12 arranged while facing each other and polarizing plate 19 outside the substrates, the vertical orienting films are formed on the surfaces of inclined films 14a and 14b formed on display electrodes 13a and 13b at the pixel opposing sections of the substrates 11 and 12, and the vertical orienting films 15a and 15b are arranged so as to incline their film surfaces at a prescribed inclination angle mutually parallel to the surfaces of substrates. Thus, the orientation of liquid crystal molecules 17a and 17b and liquid crystal molecules 18a and 18b near the vertical orienting film surfaces is controlled laterally opposite and anti-parallel mutually in respect to substrates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device for displaying television images and multimedia images and a method of manufacturing the same, and more particularly, to a liquid crystal display device having a wide field of view, a quick response and a bright display performance, and a method of manufacturing the same. About the law.

[0002]

2. Description of the Related Art As a conventional liquid crystal display device, for example, a twisted nematic (TN) mode liquid crystal display element using a nematic liquid crystal having a liquid crystal display mode having a positive dielectric anisotropy has been put to practical use. There are drawbacks such as slow response, narrow viewing angle, and the like.

On the other hand, there are display modes such as a ferroelectric liquid crystal (FLC) and an anti-ferroelectric liquid crystal, which have a quick response and a wide viewing angle, but have large seizure, shock resistance, and temperature dependence of characteristics. There are drawbacks.

Further, there is an in-plane switching (IPS) mode in which a viewing angle is extremely wide and a liquid crystal molecule is driven in a horizontal electric field in a plane, but it has a disadvantage that response is slow, an aperture ratio is low and luminance is low.

In order to display a full-color moving image on a large screen, a liquid crystal mode having a wide viewing angle, high luminance, and high-speed display performance is required.
There is currently no practical liquid crystal display mode that perfectly satisfies these factors at the same time.

In order to solve such problems, various improvements have been made in the above-mentioned liquid crystal display devices of various display modes to compensate for the respective drawbacks. Examples thereof will be described below with reference to the drawings. I do.

First, as a liquid crystal display device aiming at high brightness in at least a wide field of view, there is a liquid crystal display device in which the above-mentioned TN mode liquid crystal region is divided into two portions and the viewing angle is vertically increased (SID). 92 DIgest P7
98-801). This is because a nematic liquid crystal having a positive dielectric anisotropy is used in each display pixel of a liquid crystal display device to form two liquid crystal regions in a TN mode and different orientations of liquid crystal molecules (that is, a two-divided TN mode). ) To increase the viewing angle.

FIG. 6 is a sectional view schematically showing the liquid crystal display device. 6, reference numerals 61 and 62 denote substrates (for example, glass substrates); 63 and 64 denote display electrodes such as transparent electrodes; 65a, 65b, 66a and 66b denote alignment films;
7a and 67b show liquid crystal molecules.

In one alignment region A in FIG. 6, nematic liquid crystal molecules 67a and 67b having a positive dielectric anisotropy slightly inclined from the interface between the upper and lower substrates are present. Here, the pretilt angles of the liquid crystal molecules 67a and 67b are not the same, and the pretilt angle of 67b is larger than the pretilt angle of 67a. In the other orientation region B in FIG. 6, the magnitude of the pretilt angle with respect to the interface between the upper and lower substrates is opposite to that of the orientation region A.
The difference between the pretilt angles is set to be several degrees. That is, in FIG.
The pretilt angles of the liquid crystal molecules near b are the same, and 65b
The pretilt angles of the liquid crystal molecules near and around 66a are also the same.

When such a configuration is adopted, the orientations of the liquid crystal molecules at the center of the liquid crystal layer in the alignment regions A and B are opposite to each other, and the liquid crystal molecules in each alignment region rise in reverse with the application of the voltage. That is, the refractive index anisotropy is averaged with respect to the incident light for each pixel, and the viewing angle can be expanded. As a matter of fact, in the orientation two-split TN mode, the viewing angle is larger than in the normal TN mode, and the vertical viewing angle is about ± 35 degrees with a contrast of 10.

As an example of a conventional manufacturing method for forming alignment regions having different pretilt angles on the upper and lower substrates as described above, a photoresist is applied to an alignment film, and a predetermined mask is formed by photolithography. There is a method of repeating the operation of rubbing the desired alignment film surface in the direction.

Second, in a liquid crystal display mode using a so-called homeotropic alignment mode in which liquid crystal molecules are aligned almost vertically at an interface between alignment films, instead of a homogeneous alignment mode such as the TN mode described above, Board,
One that realizes a liquid crystal display device having a wide field of view and a high-speed response by adding an orientation division technique can be given. However, the content of this specific manufacturing method is not clear.

[0013]

However, the orientation 2
The divided TN mode has the following problems.

In this mode, only the viewing angle is increased, and the response speed is about 50 ms substantially unchanged from the TN mode. In addition, in the manufacturing method as described above, since the alignment film surface is subjected to rubbing alignment treatment by applying photolithographic technology to change the pretilt angle as described above, the alignment film surface is deteriorated and the yield is good. It is difficult to obtain a good liquid crystal display device. Recently, it has been studied to divide the alignment into two or four using a polyimide alignment film or a polysiloxane alignment film in a TN mode in a photo alignment process, but the energy required for the photo alignment is large and the irradiation time is 1-2 hours. It costs. Further, it has been proposed to further increase the viewing angle by further adding a film phase difference plate to the liquid crystal cell of the above-mentioned two-partition TN mode liquid crystal cell, but basically no improvement in response is observed because of the TN mode.

On the other hand, the liquid crystal display device utilizing the homeotropic alignment mode also has the following problems.

As a current technology for realizing a liquid crystal display device using a homeotropic alignment mode, as described in the above-mentioned alignment two-split TN mode, an alignment split homeo is formed by masking by photolithographic technology and rubbing it. The tropic mode is known. However, unlike the homogeneous alignment, the homeotropic alignment mode uses the liquid crystal molecule alignment with a pretilt angle that is almost perpendicular to the substrate.If the tilt angle is not appropriate, the vertically aligned liquid crystal molecules will be aligned in a certain direction by applying a voltage. In this case, the orientation is disturbed.

Further, in the method using a rubbing orientation treatment for imparting an inclination angle, the variation of the pretilt angle becomes large, so that defects such as rubbing streaks are generated in the display much more than in the TN mode, and the pretilt angle also decreases. It is difficult to tilt stably from the vertical.

In the homeotropic alignment mode alignment division technique, in order to obtain display characteristics that are uniform, non-uniform, and free from defects such as rubbing streaks, the display panel is substantially perpendicular to the entire display panel and in pixel units in different directions in order to obtain uniform display characteristics. In addition, it is necessary to control the alignment of liquid crystal molecules having a stable tilt angle that is slightly inclined from the vertical direction. This is a conventional homeotropic alignment mode bisection technique using a combination of a conventional rubbing method and a photolithographic method.
It means that it is more difficult than the above-mentioned TN mode alignment bisection method, and furthermore, it can be said that realization of homeotropic alignment quadripartition by rubbing treatment is almost impossible, so that display quality is low and yield is low. There is a disadvantage that it becomes a liquid crystal display device.

As described above, various approaches have been taken to realize a liquid crystal display device having a wide viewing angle, high luminance, and high-speed display performance. However, it is difficult to achieve this at present. It has become.

However, by using the homeotropic alignment mode, there is a possibility that a liquid crystal display device having a fast response and a wide field of view and bright in principle can be realized.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to propose a homeotropic type liquid crystal display device capable of producing a high yield without a rubbing process in a liquid crystal display device having a wide field of view and a quick response, and a method of manufacturing the same. And

[0021]

In order to achieve the above object, a liquid crystal display device according to the present invention comprises a display electrode and a vertical alignment film, and has a dielectric constant difference between a pair of substrates disposed opposite to each other. What is claimed is: 1. A liquid crystal display device comprising: a liquid crystal layer including liquid crystal molecules having anisotropic negative liquid crystal; and at least one polarizing plate outside the substrate, wherein a film of the vertical alignment film in a pixel-facing portion of the pair of substrates is provided. The liquid crystal molecules near the surface of the vertical alignment film are inclined substantially at the same inclination with respect to the normal to the substrate. The configuration is such that the orientation is controlled to be antiparallel to each other at the corners.

The method for manufacturing a liquid crystal display device according to the present invention
A liquid crystal layer including liquid crystal molecules having a negative dielectric anisotropy is provided between a pair of substrates, each including a display electrode and a vertical alignment film, and having pixels arranged facing each other. At least one liquid crystal layer is provided outside the substrate.
A method for manufacturing a liquid crystal display device including two polarizing plates,
A display electrode forming step of forming the display electrodes on pixel-facing portions of the substrate; a resist thin film coating forming step of coating and forming a resist thin film made of a photosensitive material on the display electrodes; An ultraviolet light exposure step of irradiating and irradiating with ultraviolet light through a photomask whose transmittance gradually changes in the pattern of the pattern, and developing, rinsing and baking the resist thin film exposed to ultraviolet light to form a gradient film having a gradually changing thickness and a sloped surface. A step of forming a gradient film to be formed on each of the pixel facing portions, an alignment film forming step of forming each of the vertical alignment films on the surface of the gradient film, and the vertical alignment formed on the pixel facing portions of the pair of substrates. The film surfaces are opposed to each other so that the inclination directions of the film surfaces are parallel to each other, and are bonded so as to have a constant gap. Has a structure characterized by having a assembling step of assembling by injecting a liquid crystal material including.

According to the above configuration, the presence of the inclined film causes the liquid crystal molecules to be inclined from the substrate, and a liquid crystal display device having a quick response and a wide field of view can be obtained.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a liquid crystal display device and a method of manufacturing the same according to an embodiment of the present invention will be described with reference to the drawings.

Embodiment 1 FIG. 1 schematically shows a liquid crystal display device according to Embodiment 1 of the present invention.
FIG. 1A is a plan view, and FIG. 1B is a cross-sectional view.

As shown in the cross-sectional view of FIG. 1B, on a pair of opposing inner surfaces of glass substrates 11 and 12, display electrodes 13a made of ITO transparent electrodes forming pixels are formed.
13b is arranged. And this display electrode 13a
And 13b, a resist film of substantially transparent photosensitive polymer material or S
It made from an insulating film such as i0 ₂ gradient film 14a and 1
4b is formed. These inclined films 14a and 14b
Means that the thickness of the substrate 11 or 1 changes gradually
The height is about 1 μm at the middle position of XX ′ and about 100 μm on each side, as shown in FIG. 1B. Is formed so that the thickness gradually decreases over the entire pixel over the length of the pixel, and the inclination angles of the inclined films 14a and 14b are about 0 and 6 degrees with respect to the substrate plane XX '. I have. Note that the height and length of the inclined film are substantially determined from the required inclination angle, and may be other values than the above values. Depending on the gap and the shape of the pixel, the above-described gradient film may be repeatedly formed in the pixel. As a result, as shown in FIG. 1B, the inclined film 14b is formed with a convex inclined object, and the inclined film 14a is formed with a concave inclined object facing each other.

A vertical alignment film 15a made of polyimide, polysiloxane, silane-based monomolecular material, or the like is provided on the opposed surfaces of the inclined films 14a and 14b which are inclined left and right at a constant inclination angle θ. And 15b are, for example, polyimide JALS-204 manufactured by Nippon Synthetic Rubber Co., Ltd.
In the case of (1), the thickness is about 1000 mm, and in the case of a silane-based monomolecular film material, the thickness is about several tens of mm, which is formed by coating and firing or coating and drying. As a result, the film surfaces of the vertical alignment films 15a and 15b formed in the above-described pixel-facing portion are aligned with the substrate surface X-.
It is arranged to be inclined with respect to X 'at an inclination angle of about 0 or 6 degrees in parallel with each other.

The substrates on which the vertical alignment films 15a and 15b are formed so as to be opposed to each other as described above are opposed to each other with a constant gap of about 4 μm. Merck's nematic liquid crystal MT-9511
When 52 is injected, the liquid crystal layer 16 is formed. At this time,
The liquid crystal molecules 17a, 1 near the surfaces of the vertical alignment films 15a, 15b
The orientations of 7b and 18a, 18b are controlled in directions opposite to each other and antiparallel with respect to the substrate, and at an inclination angle of 0 and 6 degrees which is substantially the same as the inclination angle from the normal of the substrate (that is, the display electrode). In contrast, the orientation is controlled antiparallel (at a high tilt angle of about 89 degrees opposite to each other).
As shown in (a) and (b), the liquid crystal layer 16 forms liquid crystal alignment regions C and D having alignment directions slightly inclined in directions opposite to each other with the boundary a as a boundary.

Then, the polarizing plates 19, 110, and 110 are applied to the liquid crystal cell manufactured without going through the rubbing process as described above.
When the negative film retardation plate 111 is arranged with its optical axis and optical retardation value being predetermined, a liquid crystal display device can be obtained.

A drive circuit is connected to the display electrodes 13a and 13b of the liquid crystal display device of the present embodiment shown in FIG. 1 and an applied voltage of 0-6 V is applied to the liquid crystal display device of the present embodiment. When the characteristics were evaluated, the liquid crystal molecules in the liquid crystal alignment regions C and D exhibited a characteristic in which the liquid crystal molecules in the liquid crystal alignment regions C and D were uniformly tilted to the right and left without disturbing the alignment at a voltage of about 2 V or more. , Vertical viewing angle is 12
0 degree, transmittance 70%, response speed 20 ms, a high response, a wide field of view, a high contrast display characteristic, and a high yield homeotropic liquid crystal display device without rubbing. I got it.

Embodiment 2 Hereinafter, a liquid crystal display device according to Embodiment 2 of the present invention will be described with reference to FIG. 2A is a plan view, and FIG. 2B is a cross-sectional view.

This embodiment is basically similar to the above-described first embodiment. In the first embodiment, a gradient film that is only tilted in the direction XX ′ in FIG. In contrast to the formation, the present embodiment is different in that an inclined film is formed not only in the XX 'direction but also in the YY' direction perpendicular to the XX 'direction.

In FIG. 2, reference numerals 21 and 22 denote substrates, 23
a and 23b are display electrodes; 24a and 24b are inclined films;
a and 25b are vertical alignment films, 26 is a liquid crystal layer, 27a and 27
b, 28a and 28b are liquid crystal molecules, 29 and 210 are polarizing plates, and 211 is a retardation plate.

As shown in FIGS. 2A and 2B, a switching element 212 for controlling voltage application, a substrate 22 on which a display electrode 23b is disposed, and a substrate 21 on which a display electrode 23a opposed thereto are disposed. By using the same material as that of the first embodiment and inclining the inclined films 24a and 24b in the same shape not only in the X and X 'directions but also on both sides in the YY' direction, the uneven inclined object is formed. Form each.

Then, the vertical alignment films 25a and 25b made of the same material as in the first embodiment are replaced with the inclined films 24a and
After coating and forming on the surface of the substrate 24b, the substrates are assembled facing each other with a gap of 4 μm so that the inclined films 24a and 24b inclined in parallel at a predetermined inclination angle in the vertical and horizontal directions are opposed to each other. Is injected. The liquid crystal molecules 27a and 27b and the liquid crystal molecules 28
Since a and 28b are oriented in right and left and up and down directions and antiparallel to each other and are slightly inclined from the substrate normal line (that is, the orientation is controlled at a high tilt angle in the opposite direction to the substrate). 2 (a), (b),
The liquid crystal layer 8 has four different liquid crystal alignment regions E, F, G, having alignment directions inclined in four opposite directions with respect to the boundary b.
Form H.

Then, the polarizing plates 29 and 210 and the negative film retarder 21 are added to the liquid crystal cell manufactured as described above.
1 was arranged with its optical axis and optical phase difference being predetermined, and a liquid crystal display device of the present embodiment was manufactured.

2 through the switching element 212 of the liquid crystal display device shown in FIG. 2 and between the display electrodes 23a and 23b.
When the characteristics of the liquid crystal display device of the present embodiment were evaluated by applying an applied voltage of V, the liquid crystal molecules in the liquid crystal alignment regions E, F, G, and H at about 2 V or more were aligned horizontally and vertically without disturbing the alignment. It shows the characteristics of homeotropic type alignment divided into four inclining uniformly in the direction, and the front contrast is 3
00, the horizontal viewing angle is 160 degrees, the vertical viewing angle is 160 degrees,
60% transmittance and 20 ms response speed, a super-wide-field response faster than that of Embodiment 1, high-brightness, high-contrast, high-performance display characteristics, and a high yield without rubbing. -Type liquid crystal display device was obtained.

In the first and second embodiments, two or four different liquid crystal alignment regions are formed in the liquid crystal layer in the pixel. However, only one liquid crystal alignment region having one tilt direction is formed in the pixel. Alternatively, more than four liquid crystal alignment regions may be formed. In this case, a plurality of alignment divisions are formed, and the viewing angle is further improved.

The vertical alignment film inclined at the pixel facing portion may be formed only on a part of the pixel region. However, the vertical alignment film inclined as shown in the above figure is formed over the entire pixel region. Preferably, they are arranged. Further, depending on the substrate gap and the shape of the pixel, the above-mentioned inclined film may be repeatedly formed in the pixel.

As described above, in order to further increase the field of view, a film retardation plate comprising a negative retardation plate is provided outside the opposing substrate for optical compensation. If a uniaxial anisotropic film retardation plate or the like is added as needed to compensate for the retardation, the effect is further enhanced.

In the above description, the transmission type liquid crystal display device is used. However, one of the substrates or the display electrodes may be a light reflection substrate such as Si or a light reflection display electrode such as Al. And a high-contrast reflective liquid crystal display device having a large width.

Embodiment 3 Hereinafter, a method for manufacturing a liquid crystal display device according to Embodiment 3 of the present invention will be described with reference to FIGS.
Although the manufacturing method in the present embodiment is performed in substantially the same manner for both of a pair of substrates facing each other, a process for one substrate will be described below as a representative.

First, as shown in FIG. 3A, a display electrode 32 made of ITO or the like is formed on a pixel portion of a substrate 31. Next, on each display electrode 32, a resist thin film 33 made of a positive photosensitive polymer is applied and formed. Then, the resist thin film 33 is divided into, for example, two patterns like the patterns 34 and 35, and the light transmission is performed. Ultraviolet rays 37 are irradiated and exposed through a photomask 36 whose degree is gradually changed.

Thereafter, the resist thin film 33 exposed to ultraviolet rays is developed, rinsed,
By performing the baking, as shown in FIG. 3B, the thickness of the resist thin film 33 gradually changes, and the convex inclined film 38 of the resist thin film whose surface is inclined left and right from the height center is formed on the substrate pixel. Form on the part.

Next, as shown in FIG.
On the surface of, for example, JALS manufactured by Nippon Synthetic Rubber Co., Ltd.
The -204 polyimide vertical alignment film 39 is formed. Note that, for the other substrate, a concave gradient film is manufactured in the same process as above by changing the transmissivity pattern of the photomask gradually changing from the boundary.

Then, the surfaces of the vertical alignment films formed at the pixel-facing portions of the pair of substrates are opposed to each other so that the inclination directions thereof are parallel to each other, and are bonded so as to have a gap of about 4 μm. A liquid crystal material MT-951152 containing liquid crystal molecules having a negative dielectric anisotropy is injected to assemble a liquid crystal cell, and a polarizing plate and a film phase plate are laminated to manufacture a liquid crystal display device. According to this manufacturing method, a homeotropic liquid crystal display device having two liquid crystal alignment regions in which liquid crystal molecules are aligned antiparallel to each other and tilted in opposite directions can be obtained.

In the above, the pattern of the photomask is divided into the left and right directions in the X and X 'directions substantially from the center, the transmittance is gradually changed, and the inclined film is formed by being inclined left and right.
Although a liquid crystal display device having one liquid crystal alignment region was made, the pattern may be further divided into a plurality of four, such as upper, lower, left, and right, and the transmittance may be gradually changed. A homeotropic liquid crystal display device having the same can be manufactured. Although a positive type resist is used as a resist, it goes without saying that a negative type may be used by changing the pattern transmittance of the photomask in reverse.

Embodiment 4 Hereinafter, a method for manufacturing a liquid crystal display device according to Embodiment 4 of the present invention will be described with reference to FIGS.
Although the manufacturing method in the present embodiment is performed in substantially the same manner for both of a pair of opposing substrates, a process for one substrate will be described below as a representative.

First, as shown in FIG. 4A, a display electrode 42 made of ITO or the like is formed on a pixel portion of a substrate 41, and then an insulating film 43 such as SiO ₂ is formed on the pixel portion of the substrate 41. It is formed with a thickness of about 1 μm. Further, for example, a positive resist thin film 44 is formed by coating on the insulating film 43, and the resist thin film 44 is divided into two like patterns 45 and 46, and the light transmittance is gradually changed substantially from the boundary. Through a photomask 47, ultraviolet rays 48 are irradiated and exposed.

Thereafter, the resist thin film 44 exposed to ultraviolet rays is developed, rinsed,
Baking is performed to form an inclined thin film 49 in which the thickness of the resist thin film 44 is gradually changed as shown in FIG.

Next, the insulating film 43 is dry-etched through the inclined thin film 49 to gradually incline the thickness of the insulating film, thereby forming an inclined insulating film 410 as shown in FIG.

Then, as shown in FIG. 4D, a vertical alignment film 411 is formed on the inclined insulating film 410 using, for example, polyimide JALS-204 manufactured by Japan Synthetic Rubber Co., Ltd. The other substrate is manufactured in the same process as described above, except that the gradually changing transmittance pattern of the photomask is changed in reverse from the boundary.

The surfaces of the vertical alignment films formed at the pixel-facing portions of the pair of substrates are opposed to each other so that the inclination directions thereof are parallel to each other, and are bonded so as to have a gap of about 4 μm. A liquid crystal material MT-951152 containing liquid crystal molecules having dielectric anisotropy is injected to assemble a liquid crystal cell, and a polarizing plate and a film phase plate are laminated to manufacture a liquid crystal display device. According to this manufacturing method, it is possible to obtain a homeotropic liquid crystal display device having two liquid crystal alignment regions in which liquid crystal molecules are aligned antiparallel to each other and inclined in opposite directions.

In the above, the pattern of the photomask is divided right and left from the center substantially in the X and X 'directions, the transmittance is gradually changed, and the inclined film is formed to be inclined left and right.
Although a liquid crystal display device having one liquid crystal alignment region was made, the pattern may be further divided into a plurality of regions, such as four, and the transmittance may be gradually changed. A tropic liquid crystal display device can be manufactured. Although a positive type resist is used as a resist, it goes without saying that a negative type may be used by changing the pattern transmittance of the photomask in reverse.

Embodiment 5 Hereinafter, a liquid crystal display according to Embodiment 5 of the present invention will be described with reference to FIG. FIG. 5A is a plan view, and FIG. 5B is a cross-sectional view.

In FIG. 5B, a switching element 53 composed of a TFT element for controlling voltage application and a flattening film 54 for flattening the surface on one glass substrate 52 facing the other. Is provided to planarize the substrate surface. On the flattening film 54, a display electrode 55b composed of a transparent electrode of ITO is provided with a dividing portion 55c having a width of about 10 μm in the middle to divide the display electrode. The switching element 53
And the display electrode 55b are electrically connected through a hole formed in the flattening film 54.

On the other substrate 51, a display electrode 55a is provided.
Place. An almost transparent photosensitive polymer material resist thin film or SiO ₂ which gradually and gradually changes in thickness in parallel with each other facing the display electrodes 55 a and 55 b.
The inclined films 56a and 56b made of insulating thin films such as those described above are formed and arranged.

In FIG. 5A, the shape is X,
Approximately 1 μm high in the middle of X ', approximately 50 μm to the left and right
The thickness of the entire pixel is gradually reduced over the length of m. At this time, the inclined film 56 formed opposite to the above.
The inclination angles of a and 56b are formed to be approximately 0.6 degrees parallel to the left and right with respect to the substrate plane XX '. In addition,
The height and length of the photosensitive polymer are substantially determined from the required inclination angle, and may be other values than the above values. Therefore, the inclined film 56b is formed with a convex inclined object, and the inclined film 56a is formed with a concave inclined object facing each other.

Next, the inclined films 56a inclined to the left and right,
A vertical alignment film 57 made of polyimide, polysiloxane, silane-based monomolecular material, etc.
a and 57b are, for example, JALS manufactured by Nippon Synthetic Rubber Co., Ltd.
About 1000mm thick for -204 polyimide material,
In the case of a monomolecular material, it is formed by coating and drying or coating and baking with a thickness of several tens of millimeters. The film surfaces of the vertical alignment films 57a and 57b formed in the above-mentioned pixel facing portions are arranged at an inclination angle of about 0 or 6 degrees in parallel with the substrate surface XX '. .

As described above, the vertical alignment films 57a,
Substrates 7b are formed so as to be inclined with a constant gap of about 4 μm, and a liquid crystal molecule having a negative dielectric anisotropy, for example, a nematic liquid crystal MT-951152 from Merck Inc.
To form a liquid crystal layer 58. Vertical alignment films 57a, 5
The liquid crystal molecules 59a, 59b and 510a,
10b, the orientation of the substrate is controlled in opposite directions to the left and right and anti-parallel with respect to the substrate, and is substantially the same as the inclination from the substrate normal (that is, about 8 degrees with respect to the substrate).
As shown in FIGS. 5A and 5B, the liquid crystal layer 58 has a liquid crystal alignment region I having alignment directions inclined in opposite directions with respect to the boundary c, as shown in FIGS. ,
Form J.

The polarizing plates 511 and 512 and the negative film retardation plate 513 are arranged on the liquid crystal cell thus produced without the rubbing treatment, with its optical axis and optical retardation being predetermined.
A liquid crystal display device of this embodiment mode was manufactured.

A driving circuit is connected to the display electrodes 55a and 55b of the liquid crystal display device shown in FIG. 5 formed as described above, and a voltage of 0-6 V is applied to apply characteristics of the liquid crystal display device of the present embodiment. The liquid crystal molecules 59a, 59b and 510 of the liquid crystal alignment regions I and J were evaluated at about 2 V.
a and 510b exhibited characteristics in which the respective liquid crystal alignment regions were inclined more uniformly and stably to the left and right without disturbing the alignment. This is because the alignment of the liquid crystal molecules is restricted to one by the fringe electric field distortion generated at the end of the divided portion of the display electrode and the end of the display electrode divided in the present embodiment,
Taking into account the formation of the liquid crystal alignment region by the inclined film, a more uniform and stable operating characteristic is exhibited. As a result, a front contrast of 500, a horizontal viewing angle of 160 degrees, a vertical viewing angle of 120 degrees, a transmittance of 60%, and a response speed of 20 ms are obtained. In addition, a homeotropic liquid crystal display device having a high yield without rubbing was obtained.

In the above description, the number of the liquid crystal alignment regions is two. However, the display electrodes are divided so as to form four or more liquid crystal alignment regions, and a gradient film is provided corresponding to the display electrodes to further increase the ultra wide area. It can also be a field of view.

The vertical alignment film inclined at the pixel-facing portion may be formed in a part of the pixel region. However, the vertical alignment film inclined as shown in FIG. Placed in Further, depending on the gap between the substrates and the shape of the pixel, the inclined film may be repeatedly formed in the pixel.

As described above, in order to further increase the field of view, a film retardation plate comprising a negative retardation plate is provided outside the opposing substrate for optical compensation. Even if a uniaxially anisotropic film retardation plate or the like is added as needed to compensate for the retardation, the effect is further enhanced.

Although the transmission type liquid crystal display device is described above, one of the substrates or the display electrodes may be a light reflection substrate such as Si or a light reflection display electrode such as Al. And a high-contrast reflective liquid crystal display device having a large width.

[0067]

As described above, according to the present invention, the disadvantages of the display performance of each of the conventional liquid crystal display devices in the two-divided TN mode and the IPS mode can be improved, and the liquid crystal display by the conventional two-dimensional homeotropic alignment can be improved. By eliminating the need for a rubbing process of the device and easily forming and manufacturing a tilted film on the entire substrate display electrode within the pixel, it is possible to provide a plurality of extremely stable and uniform liquid crystal alignment regions, and achieve a high manufacturing yield. It is possible to obtain a liquid crystal display device with high response speed and high brightness in an ultra-wide field of view of homeotropic type alignment division having good display quality without alignment defects.

[Brief description of the drawings]

FIG. 1 is a plan view and a cross-sectional view illustrating a configuration of a liquid crystal display device in Embodiment 1 of the present invention.

FIGS. 2A and 2B are a plan view and a cross-sectional view illustrating a configuration of a liquid crystal display device in Embodiment 2 of the present invention. FIGS.

FIG. 3 is a sectional view showing a manufacturing process of the liquid crystal display device according to Embodiment 3 of the present invention.

FIG. 4 is a sectional view showing a manufacturing process of the liquid crystal display device according to the fourth embodiment of the present invention.

5A and 5B are a plan view and a cross-sectional view illustrating a configuration of a liquid crystal display device in Embodiment 5 of the present invention.

FIG. 6 is a cross-sectional view illustrating a configuration of a conventional liquid crystal display device.

[Explanation of symbols]

 11, 12 Substrate 13a, 13b Display electrode 14a, 14b Inclined film 15a, 15b Vertical alignment film 16 Liquid crystal layer 17a, 17b, 18a, 18b Liquid crystal molecule 19, 110 Polarizing plate 111 Retardation plate 21, 22 Substrate 23a, 23b Display electrode 24a, 24b Inclined film 25a, 25b Vertical alignment film 26 Liquid crystal layer 27a, 27b, 28a, 28b Liquid crystal molecule 29, 210 Polarizing plate 211 Phase difference plate 212 Switching element 31 Substrate 32 Display electrode 33 Resist thin film 34, 35 Pattern 36 Photo mask 37 ultraviolet ray 38 inclined film 41 substrate 42 display electrode 43 insulating film 44 resist thin film 45, 46 pattern 47 photomask 48 ultraviolet light 49 inclined thin film 410 inclined insulating film 51, 52 substrate 53 switching element 54 flattening film 55a, 55b Poles 56a, 56b Inclined films 57a, 57b Vertical alignment films 58 Liquid crystal layers 59a, 59b, 510a, 510b Liquid crystal molecules 511, 512 Polarizers 513 Retardation plates 61, 62 Substrates 63, 64 Display electrodes 65a, 65b, 66a, 66b Alignment Film 67a, 67b Liquid crystal molecules

Claims (7)

[Claims] A liquid crystal layer including liquid crystal molecules having a negative dielectric anisotropy is provided between a pair of substrates disposed opposite to each other, the display electrodes and a vertical alignment film; A liquid crystal display device having at least one polarizing plate, wherein a film surface of the vertical alignment film in a pixel-facing portion of the pair of substrates is
The liquid crystal molecules in the vicinity of the vertical alignment film surface are arranged in parallel with each other at a predetermined inclination angle with respect to the substrate surface, and the liquid crystal molecules near each other at the same inclination angle with respect to the normal of the substrate. A liquid crystal display device having an anti-parallel orientation control. 2. The liquid crystal layer is divided into at least two liquid crystal alignment regions, and liquid crystal molecules in the vicinity of the vertical alignment film surface of the liquid crystal alignment region are in different directions from each other and have a substantially predetermined inclination angle with respect to the substrate normal. 2. The liquid crystal display device according to claim 1, wherein the alignment is controlled to be antiparallel. 3. The liquid crystal display device according to claim 1, wherein the vertical alignment film inclined at the pixel facing portion is disposed over the entire pixel region. 4. The liquid crystal display device according to claim 1, further comprising at least one film retardation film including a negative retardation film outside the opposing substrate. 5. A display device comprising: a pair of substrates disposed opposite to each other; a display electrode and a vertical alignment film, wherein at least one of the display electrodes formed in pixels of the substrate is divided, and A flattening film for flattening the surface under one of the display electrodes and a switching element connected to the display electrode through a hole in the flattening film, and a dielectric constant arranged between the opposing substrates. An anisotropic liquid crystal display device having a negative nematic liquid crystal layer and at least one polarizing plate and a film retardation plate outside the substrate,
The liquid crystal layer is divided into at least two liquid crystal alignment regions, and the vertical alignment film surfaces of the liquid crystal alignment regions are arranged at a predetermined tilt angle in parallel with the substrate surface, and the vertical alignment film A liquid crystal display device wherein the liquid crystal molecules in the vicinity of a plane are aligned in directions different from each other and antiparallel to each other at substantially the same inclination angle with respect to the normal to the substrate. 6. A liquid crystal layer including liquid crystal molecules having a negative dielectric anisotropy is provided between a pair of substrates each having a display electrode and a vertical alignment film, and having pixels arranged to face each other. A method for manufacturing a liquid crystal display device comprising at least one polarizing plate on the outside, comprising: a display electrode forming step of forming the display electrodes on pixel-facing portions of the substrate; and a photosensitive material on each of the display electrodes. A resist thin film application forming step of applying and forming a resist thin film consisting of, an ultraviolet light exposing step of irradiating and exposing the resist thin film with ultraviolet light through a photomask whose transmittance gradually changes in a predetermined pattern, and Developing, rinsing, baking and gradually changing the thickness to form a gradient film having a gradient surface on each of the pixel-facing portions, and forming a gradient film on the surface of the gradient film. An alignment film forming step of forming each of the vertical alignment films, and the vertical alignment films formed on the pixel-facing portions of the pair of substrates are opposed to each other so that the inclination directions of the surfaces are parallel to each other, and have a certain gap. And bonding the liquid crystal material containing the liquid crystal molecules into the gap to assemble the liquid crystal material. 7. A liquid crystal layer including liquid crystal molecules having a negative dielectric anisotropy is provided between a pair of substrates each having a display electrode and a vertical alignment film, and having pixels arranged to face each other. A method for manufacturing a liquid crystal display device comprising at least one polarizing plate on the outside, comprising: a display electrode forming step of forming the display electrodes on pixel-facing portions of the substrate; and an insulating thin film formed on the display electrodes. Forming an insulating thin film, forming a resist thin film made of a photosensitive polymer material on the insulating thin film, and exposing the resist thin film to ultraviolet light through a photomask whose transmittance gradually changes in a predetermined pattern, followed by development. Rinsing, baking, and forming an inclined thin film in which the thickness of the resist thin film is gradually changed in each of the pixel facing portions; and forming the insulating film through the inclined thin film. A step of forming a tilted insulating film by forming a tilted insulating film by gradually changing the thickness of the insulating film by ly etching; an alignment film forming step of forming each of the vertical alignment films on the display electrode; The liquid crystal material containing the liquid crystal molecules is injected into the gap so that the inclination directions of the surfaces of the vertical alignment films formed at the pixel facing portions are opposed to each other so as to be parallel to each other and have a predetermined gap. And assembling the liquid crystal display device.