JPH07333612A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide a liquid crystal display device having a wide visual field angle by averaging the dependency of light transmittance upon angles. CONSTITUTION:Substraites 1, 1 are arranged apart a prescribed distance and transparent electrodes 2, 2 are formed on their inside surfaces. Projecting parts 21 having a triangular shape in side view are formed at prescribed intervals on the front surface of the one-side transparent electrode 2. The other transparent electrode 2 are nearly flat. Oriented films 3, 3 are laminated according to the shapes of both transparent electrodes 2, 2 on the transparent electrodes 2, 2. Projecting parts 22 by the projecting part 21 of the transparent electrode 2 are formed on the one oriented film 3. A liquid crystal layer 7 is formed by encapsulating nematic liquid crystals into the spacing between the oriented films 3 and 3. Polarizing plates 5, 5 are mounted at the outside surfaces of the substrates 1, 1. The surface of the oriented film 3 formed with the projecting part 22 is subjected to a rubbing treatment in a specified direction at prescribed rubbing strength. First liquid crystal regions 11 of which the orientation direction is in a direction descending along the rubbing direction and second liquid crystal regions 12 which are reverse in direction from the first liquid crystal regions 11 are formed.

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 which displays an image by adjusting the amount of light transmitted by changing the alignment direction of liquid crystal.

[0002]

2. Description of the Related Art Two transparent insulating substrates on the surface of which transparent electrodes are formed in a matrix corresponding to a plurality of pixels, and an alignment film is laminated on one surface so as to cover the transparent electrodes. Are arranged so that the alignment films face each other with a predetermined distance therebetween, nematic liquid crystal is sealed in the gap, and both substrates are sandwiched by two polarizing plates arranged so that their polarization axes are parallel to each other. Incident linearly polarized light on the nematic liquid crystal,
There is a liquid crystal display device that displays an image by adjusting the amount of transmission. In such a device, a rubbing treatment of rubbing the surface of an alignment film with a blanket in a certain direction is performed in a twisted nematic (TN) mode in which the rubbing directions of opposing alignment films are orthogonal to each other. It is used. In the TN mode, the alignment direction of the liquid crystal when no voltage is applied is spirally different by 90 ° in the vicinity of both substrates.

In this TN mode liquid crystal display device, when no voltage is applied between the pair of transparent electrodes, the linearly polarized light incident on the liquid crystal proceeds along the alignment of the liquid crystal, and 90 The emitted light that has been turned is blocked by the polarizing plate, and the pixel becomes dark. On the other hand, when a sufficient voltage is applied between the transparent electrodes, the liquid crystal changes the alignment direction to the direction orthogonal to the transparent electrodes due to the electric field effect. Therefore, the linearly polarized light passes through the liquid crystal as it is without rotating the plane of polarization, passes through the polarizing plate, and the pixel becomes bright.

However, the response speed of the TN-mode liquid crystal display device is slow, and thus it may not be suitable for displaying a moving image such as a television image. Therefore, the following device has been proposed.

FIG. 10 is a schematic partial side sectional view showing a conventional liquid crystal display device described in Japanese Patent Application Laid-Open No. 3-46622, in which 31 is a transparent insulating substrate. Two substrates
31 and 31 are arranged at a predetermined distance, and transparent electrodes 32 and 32 such as ITO are formed on the inner surface thereof. On the transparent electrodes 32, 32, alignment films 33, 33 made of polymer resin are laminated so as to cover the inner surfaces of both substrates 31, 31, and a liquid crystal in which a nematic liquid crystal is sealed in the gap between the alignment films 33, 33. Layer 37 has been formed. Polarizing plates 35, 35 are attached to the outer surfaces of the substrates 31, 31.

The facing surfaces of the alignment films 33, 33 are subjected to rubbing treatment so that their directions are parallel and opposite to each other, whereby the liquid crystal molecules 34, 34, ... Have no twist structure. , And a predetermined pretilt angle θ (angle formed by liquid crystal molecules with respect to the contact surface). In such a device, linear polarization is changed by applying a predetermined voltage between the transparent electrodes and changing the alignment direction of the liquid crystal molecules 34, 34, ... To the direction orthogonal to the substrates 31, 31 as before. Although it is transparent and transparent, the response speed is high because it has no twist structure.

FIG. 11 is a schematic partial side sectional view showing a conventional liquid crystal display device, which is configured for color display. Note that parts corresponding to those in FIG. 10 are assigned the same reference numerals and explanations thereof are omitted. A color filter 45 is formed on the inner surface of one substrate 31, and an alignment film 32 is formed on the color filter 45.
Are stacked. The color filter 45 covers the black matrix 46 formed on the inner surface of the substrate 31, the red, green or blue colored layer 47 formed corresponding to the black matrix 46, and the black matrix 46 and the colored layer 47. The protective film 48 is laminated so that the surface becomes flat.

A transparent electrode 32 corresponding to the colored layer 47 is formed on the inner surface of the substrate 31 facing it, and an alignment film 33 is laminated so as to cover the transparent electrode 32. The facing surfaces of both alignment films 33, 33 are subjected to rubbing treatment so that their directions are parallel and opposite to each other. As a result, the liquid crystal molecules 34, 34, ... Are aligned so as to have a constant alignment direction without having a twisted structure, and thus color display can be performed at a high response speed.

[0009]

In both of the conventional liquid crystal display devices described above, as shown in FIG. 10, the liquid crystal molecules 34, 34, ... When the voltage is not applied are the liquid crystal layers 37. In the thickness direction of the device, the orientation direction of molecules is substantially constant in the device having no twist structure, but in the device having the twist structure, the orientation direction of molecules changes in a spiral shape. But the liquid crystal layer
In the plane orthogonal to the thickness direction of 37, the liquid crystal molecules 34, 34, ... Are all aligned in substantially the same direction regardless of the presence or absence of the twist structure. Therefore, there were the following problems.

FIG. 12 is a schematic view showing the state of liquid crystal molecules immediately after applying a voltage, and FIG. 13 is a partial view of FIG. When a voltage is applied between the transparent electrodes 32, 32, the orientation directions of the liquid crystal molecules 34, 34, ... Then, in the rising liquid crystal molecules 34, 34, ..., As shown in FIG.
The direction A, which is the direction on the orientation direction side of 34, 34, ..., and the direction B, which is a symmetrical direction, are significantly different. That is, since the incident angle in the direction A is smaller than that in the direction B with respect to the rising liquid crystal molecules 34, the apparent refractive index of the direction A is larger than that of the direction B, and the transmittance thereof is low.

FIG. 14 is a graph showing the angular dependence of the transmittance in the case where 8-gradation display is performed in the normally white mode which is one of the TN modes. As is clear from FIG. 14, the transmittance of the light of gradations 1 to 6 decreases as the viewing angle goes from the front (0 °) to the direction A side, but the light of gradation 0 slightly increases. ing. Therefore, at the angle X of the viewing angle A, the gradation 0 and the gradation 1 have the same transmittance, and at the angle X, the gradation 0 and the gradation 1 cannot be distinguished from each other. There is a crush.

On the other hand, the transmittance of the light of gradations 0 to 6 increases as the viewing angle goes from the front to the direction B, but the transmittance of the light of gradation 7 decreases conversely. . Therefore, at the viewing angle of the angle B in the direction B, the gradation 7 and the gradation 6 have the same transmittance, and the gradation collapse occurs. Therefore, the viewing angle capable of discriminating all gradations is in the range of angles X to Y, and there is a problem that the viewing angle is narrower than that of other display devices such as a cathode ray tube.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a first liquid crystal region having a substantially constant alignment direction in a plane orthogonal to the thickness direction of a liquid crystal layer. A second liquid crystal layer having an alignment direction different from that of the first liquid crystal region,
An object of the present invention is to provide a liquid crystal display device having a wide viewing angle by averaging the angle dependence of light transmittance by having a liquid crystal region. Another object is to have the first liquid crystal region and the second liquid crystal region in the liquid crystal layer formed in the gap of the substrate having the color filter on one side, so that the angular dependence of the light transmittance is averaged. To provide a color liquid crystal display device having a wide viewing angle.

Still another object is to form a concavo-convex film on one of the alignment films and make its rubbing density higher than that of the other alignment film to form the first liquid crystal region and the second liquid crystal region, thereby providing a wide viewing angle. An object is to provide a liquid crystal display device.
Another object of the present invention is to provide a liquid crystal display device having a wide viewing angle by forming the first liquid crystal region and the second liquid crystal region by forming irregularities at different positions on the facing alignment films.

[0015]

A liquid crystal display device according to a first aspect of the present invention is orthogonal to the thickness direction of a liquid crystal layer formed in a gap between two substrates in a state where a voltage is not applied to a transparent electrode. A first liquid crystal region in which the alignment direction of liquid crystal molecules is substantially constant in the plane, and a second liquid crystal region in which the alignment direction is different from the first liquid crystal region
It is characterized by having a liquid crystal region.

A liquid crystal display device according to a second invention is characterized in that, in the first invention, the first liquid crystal region and the second liquid crystal region are formed over substantially the entire region in the thickness direction of the liquid crystal layer.

In the liquid crystal display device according to the third aspect of the present invention, in a state in which no voltage is applied to the transparent electrode, the liquid crystal layer formed in the gap between the substrates having the color filter on one side is in a plane orthogonal to the thickness direction. A liquid crystal display device comprising: a first liquid crystal region in which the alignment direction of liquid crystal molecules is substantially constant; and a second liquid crystal region in which the alignment direction is different from the first liquid crystal region.

A liquid crystal display device according to a fourth invention is the liquid crystal display device according to the third invention, wherein the first liquid crystal region and the second liquid crystal region are formed over substantially the entire region in the thickness direction of the liquid crystal layer. apparatus.

The liquid crystal display device according to the fifth invention is
In the second, third or fourth invention, a plurality of convex portions are formed on the alignment film of one substrate, and a first liquid crystal region and a second liquid crystal region are formed on each of the convex portions. To do.

A liquid crystal display device according to a sixth aspect of the present invention is characterized in that, in the fifth aspect, the convex portion has a pyramidal shape, a trapezoidal shape, a pillar shape, or a hemispherical shape.

A liquid crystal display device according to a seventh invention is characterized in that, in the fifth invention, the convex portions are formed in a stripe shape.

The liquid crystal display device according to the eighth invention is characterized in that, in the fifth invention, the rubbing density of the alignment film on which the convex portion is formed is higher than the rubbing density of the other alignment film.

The liquid crystal display device according to the ninth invention is
In the second, third, or fourth invention, a plurality of convex portions are formed on the alignment film on one substrate, and a plurality of convex portions are formed on the alignment film on the other substrate at different positions from the convex portions. Yes,
A first liquid crystal region is formed on each of the protrusions formed on one substrate, and a second liquid crystal region is formed on each of the protrusions formed on the other substrate.
A liquid crystal region is formed.

A liquid crystal display device according to a tenth aspect of the invention is the liquid crystal display device according to the ninth aspect of the invention, characterized in that the convex portions are columnar or trapezoidal.

The liquid crystal display device according to the eleventh invention is characterized in that, in the ninth invention, the convex portions are formed in stripes.

[0026]

In the liquid crystal display device of the first and third inventions,
A first liquid crystal region in which the alignment direction of liquid crystal molecules is substantially constant in a plane orthogonal to the thickness direction of the liquid crystal layer formed in the gap between the substrates in the state where no voltage is applied to the transparent electrode, and the alignment. It has a second liquid crystal region whose direction is different from that of the first liquid crystal region. In such a liquid crystal layer, when a voltage is applied to the transparent electrode, the first liquid crystal region and the second liquid crystal region have an angle dependency with respect to the light transmittance, but the alignment directions when no voltage is applied are different, so that the viewing angle is different. The degree of the dependency of the above-mentioned relations is substantially symmetrical.

The angle dependence of the liquid crystal layer as a whole is averaged, and the light transmittance becomes substantially constant over a wide viewing angle.
Gradation collapse is prevented. Therefore, in the liquid crystal device including the color filter, clear color display is performed with a wide viewing angle.

In the liquid crystal display device according to the second and fourth aspects of the invention, the first liquid crystal region and the second liquid crystal region are formed over substantially the entire region in the thickness direction of the liquid crystal layer, so that the above-mentioned angle dependence is obtained. The averaging is performed in almost the entire area of the liquid crystal layer, and the gradation collapse is eliminated in a wide viewing angle.

In the liquid crystal display device of the fifth, sixth and seventh inventions, a plurality of convex portions are formed on the alignment film of one substrate. When the rubbing roller is used to rub the surface of the alignment film, the rubbing treatment is performed in a certain direction with a predetermined rubbing strength while keeping the distance from the substrate to the rubbing roller constant. The rubbing density is higher than that of the portion, the pretilt angle of the convex portion is small, and the pretilt angle of the concave portion is large. As a result, the first liquid crystal region in which the alignment direction of the liquid crystal molecules is constant and the second liquid crystal region different from the first liquid crystal region are formed in the plane orthogonal to the thickness direction of the liquid crystal layer formed in the gap between the substrates. .

In the liquid crystal display device of the eighth invention, the rubbing density of the alignment film on which the convex portion is formed is higher than that of the other alignment film. On the other hand, since the alignment direction of the liquid crystal molecules is governed by the pretilt angle of the alignment film on the side that has been subjected to the strong rubbing treatment, the alignment directions of the first liquid crystal region and the second liquid crystal region are almost all in the thickness direction of the liquid crystal layer. Kept in the area.

In the liquid crystal display device of the ninth, tenth and eleventh inventions, a plurality of convex portions are formed on the alignment film of one substrate, and as described above, the convex portion is more rubbed than the concave portion. Is high. Further, in the alignment film of the other substrate, since a plurality of convex portions are formed at different positions from the convex portions, a portion having a high rubbing density on one substrate has a low rubbing strength on the other substrate. Opposite the part. Since the alignment direction of the liquid crystal molecules is governed by the pretilt angle of the alignment film with the higher rubbing density, by making the rubbing directions of both alignment films different, the direction of the pretilt angle is different, which results in one substrate A first liquid crystal region is formed on each of the formed protrusions, and a second liquid crystal region is formed on each of the protrusions formed on the other substrate.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments thereof. FIG. 1 is a schematic partial side sectional view showing a liquid crystal display device according to the present invention, in which 1 is a transparent insulating substrate. The two substrates 1 and 1 are arranged with a predetermined distance therebetween, and transparent electrodes 2 and 2 such as ITO are formed on the inner surface thereof. On the surface of one transparent electrode 2, convex portions 21 having a triangular shape in a side view are formed at predetermined intervals by taper etching, and the other transparent electrode 2 is flat. Alignment films 3 and 3 of a polymer resin are laminated on the transparent electrodes 2 and 2 according to the shapes of the transparent electrodes 2 and 2, and one of the alignment films 3 is formed by the convex portion 21 of the transparent electrode 2. The convex portion 22 is formed. A nematic liquid crystal is sealed in the gap between the alignment films 3 and 3 to form a liquid crystal layer 7. Polarizing plates 5 and 5 are attached to the outer surfaces of the substrates 1 and 1, respectively.

On the surface of the alignment film 3 on which the convex portions 22 are formed,
The rubbing process is performed in the direction of the arrow with a predetermined rubbing strength while keeping the distance from the substrate 1 to the rubbing roller constant. As a result, the convex portion 22 has a higher rubbing density than the concave portion, the convex portion 22 has a small pretilt angle, and the concave portion has a large pretilt angle. Therefore, as shown in FIG. 1, the first liquid crystal region 11 and the first liquid crystal region 11 whose alignment direction is a direction that descends along the rubbing direction.
A second liquid crystal region 12 opposite to 11 is formed.

On the other hand, the surface of the alignment film 3 formed on the flat surface is subjected to a rubbing treatment with a weaker rubbing force for the alignment film 3 on the opposite side. For example, the alignment film 3 having the above-mentioned convex portion 22 is subjected to a rubbing force such that the rubbing density is 400 mm, and the alignment film 3 formed on a flat surface is subjected to the rubbing force. Is performed with a rubbing force so that the rubbing density is 100 mm or less. As a result, the alignment directions of the liquid crystal molecules 4, 4, ... Are dominated by the alignment film 3 on the side subjected to the rubbing treatment strongly, and the alignment directions of the first liquid crystal region 11 and the second liquid crystal region 12 are The same direction is applied to almost the entire area of the liquid crystal layer 7 in the thickness direction. In order to correspond to the TN mode, the substrates 1 and 1 are arranged so that the rubbing directions of the facing alignment films are orthogonal to each other, and in order to correspond to the other modes described above, the substrate 1 is arranged so that the rubbing directions are parallel to each other. , 1 is placed.

In such a device, the transparent electrode 2,
A predetermined voltage is applied between the first liquid crystal region 11 and the second liquid crystal region 11.
The alignment direction of the liquid crystal molecules 4, 4, ...
By changing to a direction orthogonal to 1, linearly polarized light is transmitted and becomes bright. At this time, the alignment direction changes so as to rise from the liquid crystal molecules 4, 4, ... Near the center between the two transparent electrodes 2, 2, but the first liquid crystal region 11 and the second liquid crystal region 12
, The orientations of the liquid crystal molecules 4, 4, ... Are opposite, so that the angular dependence of the transmittance for incident light from an oblique direction is averaged, gradation collapse does not occur at a wide angle, and the viewing angle is wide.

FIG. 8 is a graph showing the angular dependence of the transmittance in the liquid crystal display device according to the present invention.
Shows the result in the second liquid crystal region, and (b) shows the result in the first liquid crystal region. FIG. 9 is a graph showing the angular dependence of the overall transmittance of the liquid crystal display device according to the present invention. As is clear from FIGS. 8A and 8B, when viewed microscopically, the angle dependence of the direction A parallel to the liquid crystal molecules in the first liquid crystal region and the second liquid crystal region, and the direction B orthogonal thereto The angle dependence of is almost symmetrical, and when viewed macroscopically, as is clear from FIG.
The angle dependence of the first liquid crystal region and the second liquid crystal region is averaged, the transmissivities of the respective gradations do not overlap with each other over a wide viewing angle, and gradation collapse is not caused. As a result, a wide field of view of the liquid crystal display device is realized.

FIG. 2 is a schematic partial side sectional view showing another embodiment. On the transparent electrode 2 of one substrate 1, a plurality of convex portions 24 having a rectangular side view are formed. Further, a transparent resin layer 6 is laminated on the transparent electrode 2, and a convex portion 25 having a trapezoidal side view is formed on the resin layer 6 by the edge effect of the convex portion 24 of the transparent electrode 2. . Further, the alignment film 3 is laminated on the resin layer 6 according to its shape, and the convex portion of the resin layer 6 is formed.
According to 25, a convex portion 26 having a trapezoidal side view is formed. The surface of the alignment film 3 is rubbed in a certain direction. The rubbing density for the alignment film 3 on which the convex portions 26 are formed is higher than that for the alignment film 3 facing the alignment film 3. As a result, in the liquid crystal layer, the first liquid crystal region 11 and the second liquid crystal region 11 are formed over substantially the entire region in the thickness direction as before.
The liquid crystal region 12 is formed, and gradation collapse is eliminated over a wide viewing angle.

FIG. 3 is a schematic partial side sectional view showing still another embodiment, in which the alignment film 3 is provided with a convex portion 27 having a rectangular side view. In the figure, the parts corresponding to those in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted. Also in this embodiment,
In the vicinity of both edges of the convex portion 27, the first liquid crystal region 11 and the second liquid crystal region 11
The liquid crystal region 12 is formed, and gradation collapse is eliminated over a wide viewing angle. In addition, in this embodiment, the shape of the convex portion is rectangular, but the present invention is not limited to this, and needless to say, may be a hemispherical shape.

FIG. 4 is a schematic partial side sectional view showing another embodiment. On the transparent electrode of one of the substrates 1, a plurality of convex portions 28,
28 ... are formed at a predetermined interval, and the convex portions 28, 28
A plurality of convex portions 28, 28 ... Are formed on the transparent electrode 2 of the other substrate 1 so as to face the concave portions 29, 29 ,. Alignment films 3 and 3 are laminated on the transparent electrodes 2 and 2 facing each other in accordance with the unevenness, and the surfaces of the alignment films 3 and 3 are
As indicated by the arrow, the rubbing process is performed so that the processing direction is the opposite direction.

In such an apparatus, as described above, the convex portion 28 has a higher rubbing density than the concave portion 29 in both alignment films 3 and 3. Also, the convex portions 28 of the alignment films 3 and 3 facing each other,
Since the positions of 28, ... Are different from each other, the portion with high rubbing density on one substrate faces the portion with low rubbing density on the other substrate. Since the alignment direction of the liquid crystal molecules is controlled by the pretilt angle of the alignment film having the higher rubbing density, the first liquid crystal region 11 in which the alignment direction is controlled by the pretilt angle of the convex portion 28 of one alignment film 3 is used. And the second liquid crystal region whose alignment direction is controlled by the pretilt angle of the convex portion 28 of the other alignment film 3.
12 are formed.

As a result, the alignment directions of the liquid crystal molecules 4, 4, ... In the first liquid crystal region 11 and the second liquid crystal region 12 are substantially symmetrical with respect to the axis of the liquid crystal layer 7 in the thickness direction, and the average of the angle dependence is obtained. Is improved, and gradation collapse is eliminated over a wider viewing angle. In this embodiment, the pillar-shaped convex portion is formed, but the present invention is not limited to this, and it goes without saying that it may be trapezoidal.

5 and 6 are schematic partial side sectional views showing another embodiment of the liquid crystal display device shown in FIG.
In this case, by forming irregularities on the resin layers 6 and 6 disposed between the transparent electrodes 2 and 2 and the alignment films 3 and 3, convex portions 28, 28, ... and concave portions are formed on the surfaces of both transparent electrodes 2 and 2. 29, 29, ...
Has been formed. Further, in FIG. 6, the transparent electrodes 2, 2
By forming the stripe-shaped convex portions 40, 40, ... In the resin layers 6, 6 disposed between the transparent electrodes 2 and 2, the stripe-shaped convex portions 41, 41, ... and recesses 42, 42 ,. And both alignment films 3, 3
The surface of is subjected to rubbing treatment so that it is substantially orthogonal to the stripe-shaped convex portions 41, 41, ... And the processing direction is opposite. As a result, the first liquid crystal region and the second liquid crystal region
The liquid crystal region is formed, and the gradation collapse is eliminated over a wide viewing angle.

FIG. 7 is a schematic partial side sectional view showing another liquid crystal display device according to the present invention, which is applied to color display. A color filter 15 is formed on the inner surface of one substrate 1. The color filter 15 includes a black matrix 16 formed on the surface of the substrate 1 and a black matrix.
A red, green or blue colored layer 17 formed in accordance with 16 and a protective film 18 laminated so as to cover the black matrix 16 and the colored layer 17. A transparent electrode 3 having a trapezoidal convex portion in side view is laminated on the protective film 18, and an alignment in which a transparent portion 3 is laminated so as to cover the transparent electrode 3 and a trapezoidal convex portion 43 in side view is formed. The film 3 is formed. A transparent electrode 2 is formed on the inner surface of the opposing substrate 1 corresponding to the colored layer 17, and an alignment film 3 is formed so as to cover the transparent electrode 2.

Then, as shown by the arrow in the figure, both alignment films 3 and 3 are subjected to rubbing treatment so that the treatment directions are opposite to each other, and the rubbing density is such that the convex portions 43 are formed. Membrane 3 is higher. As a result, the first liquid crystal region 11 and the second liquid crystal region 12 are formed as before, and the gradation collapse is eliminated over a wide viewing angle. In addition, in this embodiment, the shape of the convex portion 43 formed on the alignment film 3 is trapezoidal in side view, but the present invention is not limited to this, and may be a pyramid shape, a rectangular shape, or a hemispherical shape. However, it goes without saying that they may be stripe-shaped. Further, convex portions may be formed on the surfaces of the alignment films 3 and 3 so that the positions thereof are different.

[0045]

As described above in detail, in the liquid crystal display device according to the first and third inventions, when the voltage is not applied to the transparent electrode, the thickness direction of the liquid crystal layer formed in the gap between the substrates is adjusted. Since the liquid crystal molecules have a first liquid crystal region in which the alignment direction of the liquid crystal molecules is substantially constant and a second liquid crystal region in which the alignment direction is different from the first liquid crystal region in a plane orthogonal to, Dependencies are averaged. As a result, the transmittance becomes substantially constant over a wide viewing angle, gradation collapse at an intermediate level is prevented, and the viewing angle is widened.

In the liquid crystal display device of the second and fourth inventions, the first liquid crystal region and the second liquid crystal region are formed over substantially the entire region in the thickness direction of the liquid crystal layer, so that the viewing angle is wider. Become.

In the liquid crystal display device of the fifth, sixth and seventh inventions, the first liquid crystal region and the second liquid crystal region are formed by the plurality of convex portions formed on the alignment film of one substrate. Therefore, the number of manufacturing steps can be reduced as much as possible.

In the liquid crystal display device according to the eighth aspect of the invention, the rubbing density of the alignment film on which the convex portion is formed is higher than the rubbing density of the other alignment film.
The alignment direction of the liquid crystal region is maintained in substantially the entire region in the thickness direction of the liquid crystal layer, and the angle dependence is averaged in the substantially entire region in the thickness direction of the liquid crystal layer.

In the liquid crystal display device of the ninth, tenth, and eleventh inventions, the sizes of the first liquid crystal region and the second liquid crystal region are in proportion to the area ratio of the convex portion and the concave portion, so that both are easily formed. The sizes of the crystal regions can be the same. In addition, the pretilt angles of the first liquid crystal region and the second liquid crystal region can be set to the same size, and the angle dependence can be highly averaged. The present invention has excellent effects.

[Brief description of drawings]

FIG. 1 is a schematic partial side cross section showing a liquid crystal display device according to the present invention.

FIG. 2 is a schematic partial side sectional view showing another embodiment.

FIG. 3 is a schematic partial side sectional view showing still another embodiment.

FIG. 4 is a schematic partial side sectional view showing another embodiment.

5 is a schematic partial side sectional view showing another embodiment of the liquid crystal display device shown in FIG.

6 is a schematic partial side sectional view showing another embodiment of the liquid crystal display device shown in FIG.

FIG. 7 is a schematic partial side sectional view showing another liquid crystal display device according to the present invention.

FIG. 8 is a graph showing the angular dependence of transmittance in the liquid crystal display device according to the present invention.

FIG. 9 is a graph showing the angular dependence of the overall transmittance of the liquid crystal display device according to the present invention.

FIG. 10 is a schematic partial side sectional view showing a conventional liquid crystal display device.

FIG. 11 is a schematic partial side sectional view showing a conventional liquid crystal display device.

FIG. 12 is a schematic diagram showing a state of liquid crystal molecules immediately after a voltage is applied.

FIG. 13 is a partial view of FIG.

FIG. 14 is a graph showing the angular dependence of the transmittance when 8-gradation display is performed in the normally white mode, which is one of the TN modes.

[Explanation of symbols] 1 substrate, 2 transparent electrodes, 3 alignment film, 4 liquid crystal molecules,
5 polarizing plate, 7 liquid crystal layer, 11 first liquid crystal region, 12
2nd liquid crystal area | region, 21 convex part, 22 convex part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hayato Takasago, 997 Miyoshi, Nishigoshi-cho, Kikuchi-gun, Kumamoto Prefecture Advanced Display Co., Ltd.・ In the display

Claims (11)

[Claims] 1. Two substrates, each having a transparent electrode and an alignment film formed on the surface thereof in this order, are arranged such that the alignment films face each other at a predetermined distance, and a gap is formed between the two substrates. In a liquid crystal display device in which a liquid crystal layer is formed by encapsulating liquid crystal, in the state in which a voltage is not applied to the transparent electrode, the alignment direction of liquid crystal molecules in a plane orthogonal to the thickness direction of the liquid crystal layer. Is substantially constant, and the alignment direction is the first
A liquid crystal display device having a second liquid crystal region different from the liquid crystal region. 2. The liquid crystal display device according to claim 1, wherein the first liquid crystal region and the second liquid crystal region are formed over substantially the entire region in the thickness direction of the liquid crystal layer. 3. A substrate on which a transparent electrode and an alignment film are formed in this order, and a substrate on which a color filter, a transparent electrode and an alignment film are formed in this order, on the surface of the alignment film. In a liquid crystal display device in which films are arranged so as to face each other, and liquid crystal is sealed in a gap between both substrates to form a liquid crystal layer, the liquid crystal layer is formed in a state in which a voltage is not applied to the transparent electrode. A first liquid crystal region in which the alignment direction of the liquid crystal molecules is substantially constant in a plane orthogonal to the thickness direction of the
A liquid crystal display device having a second liquid crystal region different from the liquid crystal region. 4. The liquid crystal display device according to claim 3, wherein the first liquid crystal region and the second liquid crystal region are formed over substantially the entire region of the liquid crystal layer in the thickness direction. 5. The alignment film on one of the substrates is formed with a plurality of protrusions, and each of the protrusions is formed with a first liquid crystal region and a second liquid crystal region. 4. The liquid crystal display device according to 4. 6. The liquid crystal display device according to claim 5, wherein the convex portion has a pyramidal shape, a trapezoidal shape, a pillar shape, or a hemispherical shape. 7. The liquid crystal display device according to claim 5, wherein the convex portions are formed in a stripe shape. 8. The rubbing density of the alignment film on which the convex portion is formed is higher than the rubbing density of the other alignment film.
The described liquid crystal display device. 9. An alignment film on one substrate is formed with a plurality of protrusions, and an alignment film on the other substrate is formed with a plurality of protrusions at different positions from the protrusions. 5. The first liquid crystal region is formed on each of the protrusions formed on one substrate, and the second liquid crystal region is formed on each of the protrusions formed on the other substrate. Liquid crystal display device. 10. The liquid crystal display device according to claim 9, wherein the protrusion has a pillar shape or a trapezoid shape. 11. The liquid crystal display device according to claim 9, wherein the convex portions are formed in a stripe shape.