JPH10186365A - Liquid crystal display element, and manufacture of oriented substrate to be used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liq. crystal display element that can be quickly manufactured by simplifying the manufacturing process, and to provide a manufacturing method for an oriented substrate to be used therefor. SOLUTION: The liq. crystal display element is constituted to form at least one substrate of a pair of substrates so that a vertically oriented film and a horizontally oriented film are arranged on the surface on the display medium side in a state where the vertically oriented film is surrounded by the horizontally oriented film by every picture element, that a cell gap of the vertically oriented film becomes larger than the cell gap at other part, and that each picture element part of the display medium has liq. crystal molecules oriented in an axially symmetrical form with the vertically oriented film as a shaft position.

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 constituting a flat display portion of, for example, a personal computer, a word processor, an amusement device, a television device, and the like, and a method of manufacturing an alignment substrate used for the liquid crystal display device.

[0002]

2. Description of the Related Art As the above-mentioned liquid crystal display device,
A configuration in which a liquid crystal layer is sandwiched between a pair of substrates is known. In the liquid crystal display device having this configuration, FIG.
As shown in (b), when a predetermined potential is applied between the electrodes 102a and 102b provided on the surface of the substrates 101a and 101b on the side of the liquid crystal layer 103, the liquid crystal molecules 104 of the liquid crystal layer 103 therebetween are inclined halftones. State. When the liquid crystal display element in this state is observed from the A direction and the B direction, which are different from each other, the light transmittance is different in both directions, and the viewing angle characteristics are poor.

[0003] In order to improve the viewing angle characteristics, FIG.
As shown in FIG. 6A, a pair of substrates 101a and 101b
It is necessary to provide a wide viewing angle mode by providing a display medium 105 having a liquid crystal region 106 surrounded by a polymer wall 107 and having the liquid crystal region 106 oriented in at least two directions. . In addition, in FIG.
The same parts as those in FIG. 16B are denoted by the same reference numerals. In the wide viewing angle mode liquid crystal display element, even in the halftone state as described above, the liquid crystal molecules 106a in the axially symmetric portion in the liquid crystal region 106 rise in the opposite directions, and the liquid crystal molecules 106a in the A direction and the B direction. The light transmittance becomes equal, and the viewing angle characteristics are improved.

A specific example of such a wide viewing angle mode liquid crystal display device is as follows.

[0005] As the method, a polymer wall is provided in a liquid crystal cell, a polarizing plate is not required, and an alignment treatment is not required. There is a known method of controlling the movement. More specifically, this method basically matches the ordinary light refractive index of liquid crystal molecules with the refractive index of the polymer wall, and displays a transparent state when the orientation of the liquid crystal is aligned by applying a voltage. When no voltage is applied, this is a method of displaying a light scattering state due to disorder in the orientation of the liquid crystal. As a proposed method, a mixture of a liquid crystal material and a photocurable or thermosetting resin is placed in a liquid crystal cell, and then the mixture is cured by applying light or heat to the resin. To form a liquid crystal region in a polymer wall made of a resin to obtain a liquid crystal display element (Japanese Patent Application Laid-Open No. 61-502128).
issue). Further, a configuration in which this liquid crystal display element is provided between polarizing plates whose polarization axes are orthogonal to each other has been proposed (JP-A-4-338923, JP-A-4-212928).
issue).

As another method, there is a method of improving a viewing angle characteristic by using a non-scattering type polarizing plate (JP-A-5-2724).
No. 2). In this method, a mixture of a liquid crystal material and a photocurable resin is irradiated with light to cause phase separation, thereby forming a liquid crystal region in a polymer wall. In the obtained liquid crystal display element, the alignment state of the liquid crystal region is in a random state disturbed by the polymer wall, and the rising direction of the liquid crystal molecules is different in each liquid crystal domain in the liquid crystal region when voltage is applied. The apparent transmittance is the refractive index anisotropy (△ n) of the liquid crystal.
The averaging of the retardation value represented by the product of the cell width and the cell gap (d) makes the same, and the viewing angle characteristic in the halftone state is improved.

Further, it has been proposed to make the alignment state of the liquid crystal more axially symmetric than in the above two or more directions.

As a method for this, a method has been proposed in which a spherulite structure made of a crystalline polymer is provided on the surface of a substrate to make the spherulite structure axially symmetric (JP-A-6-308496).
issue). In addition, there has been proposed a method of aligning liquid crystal molecules in a random direction without performing an alignment treatment such as rubbing on an alignment film formed on a substrate (Japanese Patent Laid-Open No. 6-194655).
issue). However, in the liquid crystal display device obtained by both of these methods, since the liquid crystal molecules in the pixel are oriented in different directions, a disclination line is generated in the pixel,
Therefore, there is a disadvantage that the contrast is reduced.

Therefore, the following method has been proposed as a method for preventing the occurrence of the disclination line in the pixel.

One method is to arrange a mixture of a liquid crystal material and a polymer material in a liquid crystal cell and control the amount of light by using a photomask or the like when irradiating the mixture with light to perform photopolymerization. A liquid crystal display in which molecules are made to have an axisymmetric alignment such as a spiral in a pixel, and by controlling the liquid crystal molecules by voltage, the axisymmetric alignment such as a spiral is changed to a homeotropic state. An element has been proposed (JP-A-7-120728).

As another method, there has been proposed a method of producing an axially symmetric orientation by an orientation treatment (Japanese Patent Laid-Open No. Hei 6-1994).
265902, JP-A-6-324337). The former is a conceptual method. On the other hand, the latter is a method in which an axially symmetric narrow groove is formed on a substrate, and this is used to realize an axially symmetric alignment state. It is difficult to control the pretilt of liquid crystal molecules, and the There are drawbacks that the nation line cannot be prevented at a sufficient level, and that the axisymmetric orientation becomes unstable.

Further, there has been proposed a method capable of preventing the occurrence of disclination lines at a sufficient level (Japanese Patent Laid-Open No. 6-301015). This method is a method in which a temperature control and a voltage are applied to a display medium arranged in a liquid crystal cell in a pattern obtained by combining a temperature pattern and a voltage pattern, and a voltage is applied to make a liquid crystal region in a pixel an axially symmetric orientation. .

[0013]

However, according to the proposed method (Japanese Patent Laid-Open No. Hei 6-301015), during the manufacturing process, the temperature is controlled in a predetermined temperature pattern and the voltage is applied in a predetermined voltage pattern. Need to do,
Therefore, there has been a problem that the manufacturing process becomes complicated and rapid manufacturing becomes difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and a liquid crystal display element which can be manufactured quickly by simplifying a manufacturing process, and an alignment substrate used for the same. It is intended to provide a manufacturing method.

[0015]

The liquid crystal display element of the present invention includes at least a step of gradually cooling a liquid crystal-containing display medium from an isotropic phase to a nematic phase between a pair of substrates. In at least one of the pair of substrates, a vertical alignment region and a horizontal alignment region are formed on the display medium side surface, and the vertical alignment region is formed for each pixel by the horizontal alignment region. Are arranged so as to surround them, and the cell gap of the vertical alignment region is formed to be larger than the cell gap of the other portion, and each pixel portion of the display medium is positioned with the vertical alignment region as an axial position. It has a configuration having liquid crystal molecules aligned in an axially symmetrical manner, thereby achieving the above object.

In the liquid crystal display device according to the present invention, the vertical alignment region is formed at least partially at a height lower than the horizontal alignment region from the substrate provided with the vertical alignment region. Configuration.

In the liquid crystal display device of the present invention, it is preferable that at least a part of the vertical alignment region is formed in a mortar-shaped concave shape.

In the liquid crystal display device of the present invention, it is preferable that the vertical alignment region is formed to have a surface area of 10 μm ² or less.

The method for manufacturing an alignment substrate according to the present invention is a method for manufacturing a substrate used in the above-mentioned liquid crystal display device, wherein the liquid crystal molecules are axially symmetric with respect to a vertical alignment region as an axial position. For each pixel, a vertical alignment film and a horizontal alignment film are formed such that the vertical alignment film is surrounded by the horizontal alignment film, and the surface of the vertical alignment film is lower than the surface of the horizontal alignment film. Thus, the above object is achieved.

In the method for manufacturing an oriented substrate of the present invention, at least a portion where the vertical alignment film is located may be formed in a mortar-shaped concave shape.

The method for producing an alignment substrate according to the present invention is a method for producing a substrate used in the above-mentioned liquid crystal display device, wherein the liquid crystal molecules are axially symmetric with respect to a vertical alignment region as an axial position. Forming a vertical alignment film and a horizontal alignment film in this order from the substrate side, removing a part of the horizontal alignment film,
The exposed portion of the vertical alignment film is formed so as to be surrounded by the horizontal alignment film, and the surface of the exposed portion of the vertical alignment film is formed lower than the surface of the horizontal alignment film, thereby achieving the above object. Is done.

In the method of manufacturing an oriented substrate according to the present invention, the substrate may be used in which at least a portion where the exposed portion of the vertical alignment film is located is formed in a mortar-shaped concave shape.

The method of manufacturing a substrate according to the present invention is a method of manufacturing a substrate used in the above-described liquid crystal display element, wherein the liquid crystal molecules are axially symmetric with respect to a vertical alignment region as an axial position. A horizontal alignment film is formed on a substrate in which a formation portion is formed in a mortar-shaped concave shape, a process for roughening a part of the surface of the horizontal alignment film is performed, and a vertical alignment region obtained by the process is converted into a horizontal alignment region. , And formed lower than the surface of the horizontal alignment region, thereby achieving the above object.

In the method for manufacturing an oriented substrate according to the present invention, a technique of irradiating ultraviolet light, visible light, infrared light, laser light, an electron beam, an ion beam or X-rays can be used for the treatment. In the above treatment, a surfactant, an acid solution, and a reactive gas can be used.

The operation of the present invention will be described below.

In the present invention, the vertical alignment region and the horizontal alignment region provided on the display medium side surface of the alignment substrate are arranged for each pixel so that the vertical alignment region surrounds the horizontal alignment region. Therefore, the liquid crystal molecules in contact with the vertical alignment region are vertically aligned, and the liquid crystal molecules in contact with the horizontal alignment region are horizontally aligned, so that an axially symmetric alignment is obtained with the vertical alignment region as an axial position. Further, since the cell gap in the vertical alignment region is larger than the cell gap in the other portions, the axis position is changed during the step of gradually cooling the liquid crystal from the isotropic phase to the nematic phase. It is easy to become a large vertical alignment region, and it is possible to obtain an axially symmetric alignment by reliably controlling the axial position.

At this time, the surface area of the vertical alignment region is 1
The thickness is preferably set to 0 μm ² or less. If the surface area of the vertical alignment region is larger than 10 μm ² , the axially symmetric alignment domain precipitates at a plurality of places in the vertical alignment region, so that the alignment is broken and the axial symmetric alignment cannot be obtained. Further, if the surface is flat, the axial position can be present in a portion where the surface area is regulated, but the axial positions of all the pixels of the liquid crystal display element cannot be aligned. It is preferable that the portion is formed to have a lower height from the substrate than the horizontal alignment region. In this way, the axial position can be arranged in the lower part, and the lower part is provided in all pixels so as to obtain an axially symmetric orientation in which the axial positions are uniform in all pixels. The shape of the lower portion is, for example, a mortar shape, and the axis is located at the lowest point.

The above action can be obtained if the surface in contact with the liquid crystal is a vertical alignment region or a horizontal alignment region. A similar effect can be obtained when not only the surface in contact with the liquid crystal but also the portion below it is of the same quality, that is, when a thick vertical alignment film or horizontal alignment film is provided.

The alignment substrate capable of performing such axially symmetric alignment includes, for each pixel on the substrate, a vertical alignment film and a horizontal alignment film, wherein the vertical alignment film is surrounded by the horizontal alignment film, and ,
It is obtained by forming the surface of the vertical alignment film to be lower than the surface of the horizontal alignment film. At this time, it is preferable to use a substrate in which at least a portion where the vertical alignment film is located is formed in a mortar-shaped concave shape.

In the above-mentioned alignment substrate, a vertical alignment film and a horizontal alignment film are formed on a substrate as a base in this order from the substrate side, and a part of the horizontal alignment film is removed to form the vertical alignment film. It is obtained when the exposed portion of the film is formed by surrounding the horizontal alignment film and the surface of the exposed portion of the vertical alignment film is lower than the surface of the horizontal alignment film. At this time, it is preferable to use a substrate in which at least a portion where the vertical alignment film exposed portion is located is formed in a mortar-shaped concave shape on the substrate as the base.

In the above-mentioned alignment substrate, a horizontal alignment film is formed on a substrate in which at least a vertical alignment film forming portion is formed in a mortar-shaped concave shape, and a process of roughening a part of the surface of the horizontal alignment film is performed. Then, the vertical alignment region obtained by the treatment is formed so as to be surrounded by the horizontal alignment region and lower than the surface of the horizontal alignment region. In the treatment, ultraviolet light, visible light, infrared light, laser light, electron beam, using a method of irradiating an ion beam or X-ray, or by using a surfactant, an acid solution, a reactive gas, The surface of the horizontal alignment film becomes rough and becomes a vertical alignment region.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be specifically described below.

In the liquid crystal display device of the present invention, a display medium comprising only a liquid crystal layer is provided between a pair of substrates, and at least one of the substrates has a vertical alignment region and a horizontal alignment region on the display medium side surface. And an alignment substrate having: The vertical alignment region and the horizontal alignment region are, for each pixel,
The vertical alignment region is arranged so as to be surrounded by the horizontal alignment region, and the vertical alignment region is formed to have a lower height from the substrate than the horizontal alignment region.

In the liquid crystal display device of the present invention thus constituted, each pixel portion of the display medium has liquid crystal molecules which are aligned axially symmetric with respect to the vertical alignment region as an axial position. Hereinafter, the reason will be described in detail.

The liquid crystal display device (ASM) disclosed in Japanese Patent Application Laid-Open No. 6-301015 has a very wide viewing angle characteristic in which liquid crystal molecules are axially symmetrically aligned for each pixel. However, in order to uniformly orient the liquid crystal molecules axially symmetrically for each pixel, it is necessary to apply a temperature and apply a voltage to the liquid crystal display element using a complicated temperature pattern and voltage pattern. Therefore, in industrial production, the production time and production cost are adversely affected.

On the vertical alignment film, at the time of deposition from the isotropic phase, liquid crystal molecules are deposited as an axially symmetric alignment. However, when there is a vertical alignment film as a whole, many axially symmetric alignment domains precipitate during the slow cooling process, and do not fuse with each other. Further, when the display is cooled to room temperature, the entire display is vertically aligned, and the display is fixed in black.

Therefore, in order to easily obtain an axially symmetric orientation,
By forming a small vertical alignment region in the center of the pixel and a horizontal alignment region in the other pixel regions, FIG. 1A shows a front view, and FIG. Since the liquid crystal molecules are continuously radially or concentrically arranged in the horizontal alignment region around the axially symmetric alignment domain in the vertical alignment region, the entire pixel can be in the axially symmetric alignment without applying a voltage.

Further, a liquid crystal isotropic phase (isotropic phase)
Since the nematic phase precipitated by slow cooling from is moved to a place where the cell gap is large, by maximizing the cell gap at the center of the pixel, the precipitated nematic phase is forcibly deposited at the center of the pixel, This is because by performing the axially symmetric alignment, it is possible to obtain a liquid crystal display element having a uniform display position and excellent uniform display quality.

The plane shape of the vertical alignment region is circular,
Shapes in which the corners are not acute, such as ellipses and polygons, are preferred. The reason is that if the angle is an acute angle, the orientation is disturbed and it is difficult to obtain an axially symmetric orientation. Also,
The surface area of the vertical alignment region is preferably 10 μm ² or less.
The reason is that when the surface area of the vertical alignment region is larger than 10 μm ² , when the nematic phase is precipitated by gradually cooling from the liquid crystal isotropic phase (isotropic phase), a plurality of axially symmetric alignment domains exist in the vertical alignment region. This is because, as a result of precipitation at a location, the orientation is lost and an axially symmetric orientation cannot be obtained.

Next, a modification of the present invention will be described.

(Method of Forming Horizontal Alignment Region (or Film) and Vertical Alignment Region (or Film)) As shown in FIG. 2, for each pixel of the substrate, a vertical alignment film and a horizontal alignment film are replaced with a vertical alignment film. Is formed in a state where is surrounded by a horizontal alignment film, and the surface of the vertical alignment film is lower than the surface of the horizontal alignment film.

As shown in FIG. 3, a vertical alignment film and a horizontal alignment film are formed on a substrate in this order from the substrate side, a part of the horizontal alignment film is removed, and an exposed portion of the vertical alignment film is removed. A method in which the vertical alignment film is formed so as to be surrounded by the horizontal alignment film and the surface of the exposed portion of the vertical alignment film is lower than the surface of the horizontal alignment film.

As shown in FIG. 4, a horizontal alignment film is formed on a substrate in which at least a vertical alignment film forming portion is formed in a mortar-shaped concave shape, and a process of roughening a part of the surface of the horizontal alignment film is performed. A method in which a vertical alignment region obtained by this treatment is formed so as to be surrounded by a horizontal alignment region and lower than the surface of the horizontal alignment region.

In the above, as a method of lowering the surface of the vertical alignment film than the surface of the horizontal alignment film, when the base is flat, the thickness of both films may be simply adjusted. If the underlayer is not flat, the thicknesses of both films are adjusted so that a desired height relationship is obtained between the surfaces. Also, in the method, the surface of the vertical alignment film naturally becomes lower than the surface of the horizontal alignment film due to the formation method itself. Further, the above and other cases include a case where the surface of each film is flat, although the heights of both films are different.
As shown in (a) or (b), it is preferable to use a substrate in which at least the vertical alignment film or at least the portion where the vertical alignment film exposed portion is located is formed in a mortar-shaped concave shape. The reason is that the axial position of the axially symmetric orientation is the lowest point of the mortar-shaped recess, and by adjusting and providing the position of the lowest point of the recess in each pixel, the axial position of the axially symmetric orientation in each pixel is adjusted. This is because they can be aligned.

(Method of forming mortar-shaped recess) A case where the mortar-shaped recess has an inverted conical shape will be described as an example.

As shown in FIG. 6, a relatively soft film is formed on a substrate, and a concave portion is formed by pressing a mold having a conical convex portion, for example, a mold, on the film or directly on the substrate. Method.

A method of laminating layers having circular holes having different diameters as shown in FIG. 7A and smoothing the cut portion with a smoothing material as shown in FIG. 7B.

8 (a) is a plan view, and FIG. 8 (b) is a sectional view. As shown in FIG. 8, a photosensitive insulating film is formed on a substrate. Using a photomask having a circular pattern and then developing.

In the above case, the light transmittance of the photomask is changed stepwise in the example shown in FIG. 8, but the light transmittance continuously changes from 100% to 0%. It may be changed. Further, the light transmittance may be 0% to 100% depending on the type of the resist used as the insulating film.
Or from 100% to 0%. For example, in the case of a positive resist, the portion corresponding to the lowest portion of the concave portion has a light transmittance of 0%, and the light transmittance gradually increases around the portion.
% To 100%, and the light transmittance of the portion without the concave portion may be 100%. In the case of a negative resist, the reverse may be used.

In the method described above, the case where the inverted conical mortar-shaped concave portion is formed is described. However, when the shape of the mortar-shaped concave portion is an inverted elliptical shape or an inverted polygonal shape, the method is omitted. It is only necessary to use a mold having a corresponding shape, a hole or a pattern mask.

(Positional relationship between mortar-shaped recess and vertical alignment region (or film)) The mortar-shaped recess is shown in FIGS.
As shown in (a) and (b), it may be present in at least a part or all of the vertical alignment region (or film). Alternatively, it may be formed in a range from a vertical alignment region (or film) to a horizontal alignment region (or film), and further has a top portion at the horizontal alignment region (or film) as shown in FIG. It may be formed to have continuous peaks and valleys.

(Process of Roughening the Surface of Horizontal Alignment Film to Form Vertical Alignment Region) This process includes a method of irradiating ultraviolet light, visible light, infrared light, laser light, an electron beam, an ion beam or X-rays. Alternatively, a surfactant, an acid solution, or a reactive gas may be used. The surface of the horizontal alignment film on which such a treatment is performed becomes a vertical alignment region due to surface roughness, and the vertical alignment region is surrounded by the horizontal alignment region by restricting a portion where the surface processing is performed to a central portion of a pixel. It becomes possible to be in the state where it fell.

(Display Medium) The display medium has a structure in which each pixel portion is a liquid crystal region surrounded by polymer walls as shown in FIG. As shown in the figure, a structure composed of only a liquid crystal layer having no polymer wall may be used. The liquid crystal material is TN or ST.
N, or ECB, OCB mode ones can be used.

(Driving Method) In addition to the simple matrix driving, the liquid crystal display element of the present invention employs amorphous silicon (a-S
a-Si.TFT (thin film transistor) having i) in a semiconductor layer, p-Si.TFT having polysilicon (p-Si) in a semiconductor layer, or MIM (metal-i)
The driving can be performed using active matrix driving using nsulator-metal, and there is no particular limitation. What is necessary is just to select from the said drive method according to the characteristic of the liquid crystal display element of this invention.

(Substrate Material) As a substrate material serving as a base, a transparent solid glass, a plastic film made of a polymer, or the like can be used. As the plastic film substrate, a material that does not absorb visible light is preferable,
For example, PET, acrylic polymer, styrene, polycarbonate and the like can be used.

Further, different types of substrates obtained by combining these two types of substrates can be used, and two types of substrates having the same thickness but different in thickness can be used in combination.

In the case of a plastic film substrate, a liquid crystal display device in which a polarizing plate is integrated can be manufactured by giving the substrate itself a polarizing ability.

Hereinafter, embodiments of the present invention will be described in more detail. However, the present invention is not limited to this.

(Embodiment 1) This embodiment is a case where a vertical alignment film is partially formed.

As one of the substrates, as shown in FIG. 9A, for example, an IT
A transparent electrode made of O (a mixture of indium oxide and tin oxide) with a thickness of 500 angstroms is used.

As shown in FIG. 9B, a photosensitive resist is applied on the substrate, and the substrate is irradiated with ultraviolet light using a photomask as shown in FIG. 10 to form spacers on the substrate.

Next, the resist is further applied onto the substrate, and the substrate is heated to 140 ° C. which is higher than the softening temperature of the resist.
Then, the mold is taken out, taken out, and pressed with a resist having a conical convex portion as shown in FIG. 9C against the resist on the substrate, as shown in FIG. 9D. Thus, a resist having a mortar-shaped concave portion is formed.

Next, on the resist, for example, JA
After forming a vertical alignment film made of LS-204 (manufactured by Nippon Synthetic Rubber Co., Ltd.), a horizontal alignment film made of photosensitive polyimide was further formed thereon.

Next, a part of the horizontal alignment film is removed by irradiating with ultraviolet light using a photomask shown in FIG. 11 and developing, so that the cross section shown in FIG. A circular exposed portion having a center is formed. This exposed portion is a portion where the horizontal alignment film is exposed. The periphery of the exposed portion is surrounded by a horizontal alignment film.

A thermosetting sealant (Structbond: XN-2) in which a glass fiber (diameter: 4.5 μm) as a spacer was mixed with the oriented substrate thus prepared.
1S) was printed and bonded to a glass substrate with ITO, which is a counter substrate. Thereby, a liquid crystal cell is obtained. The printing of the thermosetting sealant may be performed on the counter substrate side.

Next, a liquid crystal material to which a chiral agent was added so as to be twisted by 90 ° in the cell gap was injected into the inside of the liquid crystal cell.

Next, the liquid crystal cell is heated to a temperature at which the liquid crystal material becomes an isotropic phase.
min. At room temperature.

The liquid crystal display element thus obtained is
Observation with a polarizing microscope revealed that, for each pixel, the liquid crystal molecules were oriented in a monodomain state and axially symmetric as shown in FIG. In addition, since the center of the orientation was fixed to the center of the inverted conical shape, no roughness was visually observed on the entire screen.

When the liquid crystal display element was observed with a polarizing microscope while applying a voltage, it was observed that no disclination line was generated and the whole area was black at any applied pressure.

FIG. 14 shows the electro-optical characteristics of the liquid crystal display device. The illustrated example is a case in which two polarizing plates whose polarization axes are parallel to each other with a liquid crystal display element interposed therebetween are provided, and the measurement is performed using the polarizing plates as blanks (transmittance: 100%). FIG. 15 shows the result of the same measurement on the liquid crystal display element using the TN liquid crystal of the related art, which was described with reference to FIG.

From FIGS. 14 and 15, the liquid crystal display device of the present invention does not show the reversal phenomenon of the light transmittance as seen in the conventional TN type liquid crystal display device, and the wide viewing angle direction at the time of voltage saturation. No increase in transmittance was observed. Further, no roughness was observed in the halftone.

A liquid crystal display device was manufactured by bonding two polarizing plates orthogonal to each other with the manufactured liquid crystal display element interposed therebetween.

In the present embodiment, the vertical alignment film and the horizontal alignment film are provided in a desired state only on one substrate side. However, the present invention is not limited to this. Is also good.

(Embodiment 2) This embodiment is a case where the surface is roughened by ultraviolet light.

First, in the same manner as in the first embodiment, a substrate having an inverted conical mortar-shaped recess was manufactured. Thereafter, using a photomask shown in FIG. 11, ultraviolet light (wavelength: 365 nm) was applied to only the center of the mortar-shaped concave portion at 10 J / cm ^2.
Irradiation was performed at an intensity of 3 to roughen the surface of the light-irradiated portion.

The other substrate, which is disposed so as to face the alignment substrate thus manufactured, was manufactured as follows. A thermosetting sealant (Stract Bond: XN-21S) in which glass fibers having a diameter of 4.5 μm were mixed as spacers was printed on a peripheral seal portion of a glass substrate having an electrode made of ITO. This other substrate may be manufactured before the oriented substrate subjected to the surface roughening treatment.

Next, the two substrates were opposed to each other with the electrodes disposed inside and a liquid crystal cell was fabricated.

Next, the liquid crystal cell according to the first embodiment
The same liquid crystal material as described above is injected, and the liquid crystal material is once heated to a temperature at which the liquid crystal material becomes an isotropic phase.
min. At room temperature.

When the liquid crystal display device thus manufactured was observed with a polarizing microscope, it was observed that a uniform axially symmetric orientation was obtained for each pixel. Observation with a polarizing microscope while applying a voltage to the liquid crystal display device showed that good electro-optical characteristics were obtained as in the first embodiment.

Next, two polarizing plates whose polarization axes are orthogonal to each other were attached to each other with the liquid crystal display element interposed therebetween to produce a liquid crystal display device.

(Embodiment 3) This embodiment is a case where the surface is roughened by a solution.

In the same manner as in the first embodiment, a substrate having an inverted conical mortar-shaped recess was prepared, and polyimide was applied thereon as a horizontal alignment film.

Next, a positive photosensitive resist was applied, and a pattern in which the resist was present was formed using a photomask shown in FIG.

Next, the surface of this substrate was treated with 0.2% NaO
By contacting with an aqueous solution of H, the surface not protected by the resist, that is, the surface of the central portion of the pixel of the horizontal alignment film made of polyimide was roughened.

Next, the positive photosensitive resist was peeled off to obtain an alignment substrate having a vertical alignment region at the center of the pixel and the periphery of the vertical alignment region being surrounded by a horizontal alignment region.

Next, this alignment substrate and the other substrate manufactured in the same manner as in the above-described embodiment are bonded together,
A liquid crystal cell was manufactured.

Next, the liquid crystal cell according to the first embodiment
The same liquid crystal material as described above is injected, and the liquid crystal material is once heated to a temperature at which the liquid crystal material becomes an isotropic phase.
min. At room temperature.

When the liquid crystal display device thus manufactured was observed with a polarizing microscope, it was observed that a uniform axially symmetric alignment was obtained for each pixel. Observation with a polarizing microscope while applying a voltage to the liquid crystal display device showed that good electro-optical characteristics were obtained as in the first embodiment.

Next, two polarizing plates whose polarization axes are orthogonal to each other were attached to each other with the liquid crystal display element interposed therebetween to produce a liquid crystal display device.

[0090]

As described above in detail, in the case of the present invention, when a liquid crystal material is gradually cooled from an isotropic phase to precipitate a nematic phase, voltage pattern control conventionally required can be eliminated. Therefore, it is possible to rapidly manufacture a liquid crystal display element by simplifying the manufacturing process, and to manufacture an alignment substrate capable of realizing the same.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams illustrating the principle of alignment of liquid crystal molecules in the present invention, wherein FIG. 1A is a cross-sectional view and FIG.

FIG. 2 shows a horizontal alignment region (or film) used in the present invention.
FIG. 4 is a cross-sectional view illustrating an example of a method for forming a vertical alignment region (or film).

FIG. 3 shows a horizontal alignment region (or film) used in the present invention.
FIG. 9 is a cross-sectional view illustrating another example of a method for forming a vertical alignment region (or film).

FIG. 4 is a horizontal alignment region (or film) used in the present invention.
FIG. 11 is a cross-sectional view illustrating still another example of a method for forming a vertical alignment region (or film).

5A and 5B are cross-sectional views showing a positional relationship between a mortar-shaped concave portion and a vertical alignment film according to the present invention, wherein FIG. 5A is a diagram corresponding to FIG. 2 and FIG. 5B is a diagram corresponding to FIG. It is.

FIG. 6 is a cross-sectional view illustrating an example of a method for forming a mortar-shaped recess in the present invention.

FIG. 7 is a process drawing (cross-sectional view) showing another example of the method for forming a mortar-shaped recess in the present invention.

8A and 8B are views showing still another example of the method for forming a mortar-shaped recess in the present invention, wherein FIG. 8A is a plan view and FIG. 8B is a cross-sectional view.

FIG. 9 is a cross-sectional view showing a step of forming a mortar-shaped recess in the first embodiment.

FIG. 10 is a front view showing a photomask used when forming a spacer in the first embodiment.

FIG. 11 is a front view showing a photomask used when forming a mortar-shaped recess in the first, second, and third embodiments.

FIG. 12 is a cross-sectional view illustrating a cross-sectional state of the alignment substrate manufactured in the first embodiment.

FIG. 13 is a schematic diagram (plan view) showing the results of observing the liquid crystal display devices manufactured in Embodiments 1, 2, and 3 with a polarizing microscope.

FIG. 14 is a diagram showing the electro-optical characteristics of the liquid crystal display devices manufactured in Embodiments 1, 2, and 3.

FIG. 15 is a diagram showing electro-optical characteristics of a conventional TN type liquid crystal display element.

FIG. 16 is a cross-sectional view showing a configuration of a conventional liquid crystal display element.

[Explanation of symbols]

 101a, 101b Substrates 102a, 102b Electrode 103 Liquid Crystal Layer 104 Liquid Crystal Molecules 105 Display Medium 106 Liquid Crystal Region 107 Polymer Wall

Claims (11)

[Claims] 1. A liquid crystal display element comprising a display medium containing a liquid crystal between a pair of substrates at least including a step of gradually cooling the liquid crystal from an isotropic phase to a nematic phase. At least one of the substrates is arranged with a vertical alignment region and a horizontal alignment region on the display medium side surface, with the horizontal alignment region surrounding the vertical alignment region for each pixel, and the vertical alignment region. A configuration in which the cell gap in the region is formed to be larger than the cell gap in the other portion, and each pixel portion of the display medium has liquid crystal molecules aligned in an axially symmetric manner with the vertical alignment region as an axial position. Liquid crystal display device. 2. The vertical alignment region according to claim 1, wherein at least a part of the vertical alignment region is formed to be lower in height than the horizontal alignment region from the substrate provided with the vertical alignment region. Liquid crystal display element. 3. At least a part of the vertical alignment region includes:
3. The liquid crystal display element according to claim 2, wherein the liquid crystal display element is formed in a mortar-shaped concave shape. 4. The vertical alignment region has a surface area of 10
The liquid crystal display device according to claim 1, wherein the liquid crystal display device is formed to have a thickness of not more than μm ² . 5. A method for producing an alignment substrate used in the liquid crystal display element according to claim 1 or 4, wherein the liquid crystal molecules are axially symmetric with respect to a vertical alignment region as an axial position. For each pixel, a vertical alignment film and a horizontal alignment film are formed such that the vertical alignment film is surrounded by the horizontal alignment film, and the surface of the vertical alignment film is lower than the surface of the horizontal alignment film. A method for manufacturing an oriented substrate. 6. The method for manufacturing an oriented substrate according to claim 5, wherein at least a portion where the vertical alignment film is located is formed in a mortar-shaped concave shape. 7. A method for producing an alignment substrate used for the liquid crystal display device according to claim 1 or 4, wherein the liquid crystal molecules are axially symmetric with respect to a vertical alignment region as an axial position. A vertical alignment film and a horizontal alignment film are formed in this order from the substrate side, a part of the horizontal alignment film is removed, and the exposed portion of the vertical alignment film is surrounded by the horizontal alignment film. A method for manufacturing an alignment substrate, wherein the surface of the exposed portion of the alignment film is formed lower than the surface of the horizontal alignment film. 8. The method for manufacturing an oriented substrate according to claim 7, wherein at least a portion where the vertical alignment film exposed portion is located is formed in a mortar-shaped concave shape. 9. A method for producing an alignment substrate used in the liquid crystal display element according to claim 1 or 4, wherein the liquid crystal molecules are axially symmetric with respect to a vertical alignment region as an axial position, at least a vertical alignment film. A horizontal alignment film is formed on a substrate in which a formation portion is formed in a mortar-shaped concave shape, a process for roughening a part of the surface of the horizontal alignment film is performed, and a vertical alignment region obtained by the process is converted into a horizontal alignment region. A method for manufacturing an alignment substrate, wherein the alignment substrate is formed so as to be surrounded by and below the surface of the horizontal alignment region. 10. The method for manufacturing an oriented substrate according to claim 9, wherein a method of irradiating ultraviolet light, visible light, infrared light, laser light, an electron beam, an ion beam, or X-rays is used for the treatment. 11. The method according to claim 9, wherein a surfactant, an acid solution, and a reactive gas are used for the treatment.