JPH0961826A - Production of liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a liquid crystal display device having a large pretilt angle, to suppress the occurrence of the reverse tilt discrination line on a display screen and to improve display grade by causing the phase transition of the liquid crystal material between substrates from an isotropic phase to a liquid crystal phase in the state of impressing an electric field or magnetic field between the substrates. SOLUTION: The fluorine type mixed nematic liquid crystal material 7 contg. a chiral agent is heated in the state of putting an empty cell into a high-temp. chamber 6 and is injected between the substrates 1 disposed to face each other in an isotropic state in order to inject liquid crystal material between the substrates. The liquid crystal cell of the high-temp. state is taken out of the high-temp. chamber 6 and is gradually cooled down to the phase transition temp. in the state of impressing the electric field between the substrates 1 by an AC power source 5. The liquid crystal material 7 causes the phase transition from an isotropic phase to a nematic phase when the material is cooled down to the phase transition temp. or below. Liquid crystal molecules 7 are oriented in a rising state when the liquid crystal cell is gradually cooled while the electric field is impressed thereon by the AC power source 5. At this time, the tilt angle of the liquid crystal molecules 7 is large.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly to a method for manufacturing a liquid crystal display device having a liquid crystal material having a pretilt.

[0002]

2. Description of the Related Art FIG. 9 is a cross-sectional view of a liquid crystal display device for explaining a conventional method of manufacturing a liquid crystal display device.

FIG. 9A shows a process of manufacturing an empty cell.
First, the glass substrate 51 is prepared, and the alignment film 53 is formed on the glass substrate 51. Next, an optical alignment process is performed on the alignment film 53. As described above, the two substrates 1 are manufactured and arranged so as to face each other. By twisting the two substrates 1 by 90 ° from each other, a twisted nematic liquid crystal cell twisted by 90 ° can be manufactured. Two boards 1
Gap control agent (not shown) is sandwiched between
The gap between the substrates is set to a predetermined value.

FIG. 9B shows a liquid crystal injection process. The empty cell is heated, and the liquid crystal material 57 in the isotropic phase (isotropic phase) is injected between the substrates 51. At the time of injecting liquid crystal, the liquid crystal material 57 is heated to the NI (nematic-isotropic) phase transition temperature or higher to be in the isotropic phase.

FIG. 9C shows a cooling process of the liquid crystal cell. The liquid crystal cell in a high temperature state is gradually cooled to bring the liquid crystal material 57 into a nematic phase (liquid crystal phase). The liquid crystal material 57 is N-
A nematic phase is obtained by cooling to a temperature below the I phase transition temperature. Even if the orientation force on the substrate 51 is weak, uniform orientation can be obtained by gradually cooling from the isotropic phase.

[0006]

Problems to be Solved by the Invention In FIG. 9 (A),
It has been shown that the alignment film 53 on the glass substrate 51 is subjected to optical alignment processing. As a method of performing photo-alignment treatment, a method using the following optical polarization storage film has been announced.

Method Using Silicon Polyimide Doped with Diazoamine Dye (Wayne MGibbons et al., NATURE
Vol.351 (1991) P49). Method using PVA (polyvinyl alcohol) doped with azo dye (Yasufumi Iimura et al., 18th Liquid Crystal Conference-
The 64th Annual Meeting of the Chemical Society of Japan, p34, published September 11, 1992, The Chemical Society of Japan; Jpn J. Appl. Phys. Vol.
32 (1993) pp.L93-L96).

A method using a photopolymerization photopolymer (Ma
Rtin Schadt et al., Jpn. J. Appl. Phys. Vol. 31 (1992)
pp.2155-2164). A method of horizontally aligning a liquid crystal in a direction orthogonal to the polarization direction by irradiating a polyvinyl 4-methoxycinnamate (PVC) film with polarized light.

The PVC film is irradiated with the deflected light from the direction normal to the substrate, and further from the direction normal to the substrate at a constant angle and perpendicular to the polarization direction (azimuth direction). Thereby giving an orientation having a pretilt angle.

In FIG. 9C, when the liquid crystal cell is cooled, the liquid crystal molecules 57 in the nematic phase have a pretilt depending on the alignment treatment method. Pretilt hardly occurs in the alignment treatment methods 1 to 3 above. In the above method, a slight pretilt occurs, but the pretilt angle is extremely small.

The pretilt is a state in which one end of the liquid crystal molecule in the long axis direction is lifted with respect to the substrate surface when a voltage is not applied between the substrates. The pretilt angle means an angle between the substrate surface and the long axis of liquid crystal molecules when a voltage is not applied between the substrates.

When a voltage is applied between the substrates, liquid crystal molecules having a pretilt rise from one end side which is raised with respect to the substrate surface. If all liquid crystal molecules have the same pretilt direction, all liquid crystal molecules rise in the same direction.

On the other hand, it is not determined from which end in the major axis direction the liquid crystal molecule having no pretilt rises. When all the liquid crystal molecules have no pretilt or have an extremely small pretilt angle, a region of liquid crystal molecules that rises from one end in the long axis direction and a region of liquid crystal molecules that rises from the other end occur. At the boundary of the area, a line defect (reverse tilt disclination line) is likely to appear on the liquid crystal display screen.

Particularly, when the applied voltage is near the threshold value of the liquid crystal cell, a reverse tilt disclination line is likely to occur. In addition, since the position of the reverse tilt disclination line changes due to a change in applied voltage or a lapse of time, the presence of a line defect can be visually recognized. Further, since light scattering occurs and the contrast is reduced, the display quality of the liquid crystal display device is significantly reduced.

It is an object of the present invention to provide a method of manufacturing a liquid crystal display device having a liquid crystal material having a large pretilt angle.

[0016]

A method of manufacturing a liquid crystal display device according to the present invention comprises a step of preparing a pair of substrates having at least one of them subjected to an alignment treatment, and a step of disposing the pair of substrates so as to face each other. The method includes a step of injecting a liquid crystal material and a step of causing a liquid crystal material between the substrates to undergo a phase transition from an isotropic phase to a liquid crystal phase while applying an electric field or a magnetic field between the substrates.

A liquid crystal display device having a large pretilt angle can be manufactured by causing a liquid crystal material between the substrates to undergo a phase transition from an isotropic phase to a liquid crystal phase while applying an electric field or a magnetic field between the substrates.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a liquid crystal display device according to an embodiment of the present invention will be described with reference to FIGS. 1 (A) to 6 (E) in order. First, a method for manufacturing a substrate used for a liquid crystal display device will be described.

FIG. 2 is a cross-sectional view of the substrate for explaining the manufacturing process of the substrate. A glass substrate 1 is prepared, and an indium tin oxide (ITO) film 2 is formed on the glass substrate 1. The ITO film 2 is a transparent conductive film. Furthermore, I
An alignment film 3 is formed on the TO film 2. The alignment film 3 is, for example, a PVC (polyvinyl cinnamate) film.

The ITO film 2 can be formed, for example, by sputtering or vapor deposition. The method of forming the alignment film 3 will be described below. First, 2 wt% of PVC is dissolved in a mixed solvent of monochlorobenzene and dichloromethane. This PVC
The solution is applied to the glass substrate 1 with a spinner. 100 ℃
And dried for 1 hour to form a PVC film 3 having a film thickness of about 1000Å.

The PVC film 3 is a kind of optical polarization storage film, and an alignment structure can be formed on the substrate surface by performing an optical alignment treatment. The photo-alignment process will be described later with reference to FIG.

Although the ITO film 2 is shown in a simplified manner in FIG. 2, the ITO film 2 is actually a pixel electrode connected to a thin film transistor formed on the substrate 1, and is provided separately for each pixel. ing. Note that a plurality of segment electrodes or common electrodes may be formed on the substrate 1, or the ITO film 2 may be formed on the entire surface of the substrate 1.

FIG. 3 shows a structural example of the substrate 1 having a pixel electrode. Wirings or electrodes 2a, pixel electrodes 2b, and thin film transistors Q are formed on the glass substrate 1a. The electrode 2a and the pixel electrode 2b correspond to the ITO film 2 in FIG.
The wiring 2a is connected to the pixel electrode 2b via the transistor Q. For example, the wiring 2a and the pixel electrode 2b are made of an ITO film, the electrode portion of the thin film transistor is made of doped polysilicon, the channel portion is made of polysilicon, and the gate insulating film is made of a silicon oxide film.

FIG. 4 is a diagram showing a photo-alignment treatment step.
In the photo-alignment treatment, the PVC film 3 on the surface of the substrate 1 is irradiated with light twice (first irradiation and second irradiation). The details will be described below.

FIG. 4A is a diagram showing a first irradiation method for the PVC film 3. The glass substrate 1 has PVC on its surface.
The film 3 is formed. The substrate surface is x including the x axis and the y axis
The y-plane is used and the substrate normal direction is the z-axis.

The PVC film 3 is irradiated with the first irradiation light S1 for 50 seconds. For example, light irradiation is performed using a high pressure mercury lamp. The irradiation energy is 1.5 J / cm ² , and the wavelength of the first irradiation light S1 is 313 nm.

The first irradiation light S1 is light in the z-axis direction,
It is linearly polarized light with a polarization direction α. The polarization direction α is the y-axis direction. FIG. 4B is a diagram showing a second irradiation method for the PVC film 3. The PVC film 3 is irradiated with the second irradiation light S2 for 5 seconds. The second irradiation light S2 is
Only the irradiation direction and the polarization direction are different, and the irradiation energy and the light wavelength are the same.

The second irradiation light S2 is linearly polarized light having a polarization direction β and having an incident angle (polar angle) θ = 45 ° with respect to the substrate normal direction (z-axis direction). The polarization direction β is a direction within the xz plane and is a direction orthogonal to the polarization direction α of the first irradiation light S1.

FIG. 4C is a diagram showing the alignment direction DR of the liquid crystal molecules generated by the first irradiation and the second irradiation. When the alignment film 3 is filled with the liquid crystal material, the long axis of the liquid crystal molecule at the interface between the alignment film 3 and the liquid crystal material has an arrow DR.
Orient in the direction of.

The orientation direction DR is a direction orthogonal to the polarization direction α of the second irradiation light S1 and is a direction in the xz plane. The polar angle δ of the alignment direction DR depends on the incident light θ of the second irradiation light S2. The larger the incident angle θ, the larger the polar angle δ.
In other words, the larger the incident angle θ, the smaller the pretilt angle (90 ° −δ) of the liquid crystal molecules.

Next, a method of manufacturing a liquid crystal display device using the two substrates thus manufactured will be described. Figure 1 (A)
It is a figure which shows the manufacturing process of an empty cell. An ITO film 2 and an alignment film (PVC film) 3 are formed on the surface of the glass substrate 1. Two substrates 1 are prepared, and they are arranged to face each other with a gap control agent (not shown) interposed therebetween. The gap between the substrates is fixed at 5 μm by the gap control agent.

The two substrates are different in the direction of the above-mentioned photo-alignment treatment. The orientation treatment direction of one of the substrates is deviated by 90 ° in the plane of the substrate as compared with the other. This is 9
This is for producing a twisted nematic liquid crystal layer twisted by 0 °.

FIG. 1B is a diagram showing a step of energizing the empty cell at high temperature. The empty cell manufactured by the above process is put in the high temperature tank 6. The high temperature tank 6 has a heater and heats the empty cell to a temperature above the NI phase transition point. The NI phase transition point is a phase transition point of a liquid crystal material to be injected between the substrates in a later step.

The AC power source 5 is connected between the ITO films 2 formed on the pair of substrates 1, respectively. When the pixel electrodes 2 are formed on the substrate 1 (FIG. 3), the thin film transistors corresponding to all pixels are turned on and a voltage is applied to all pixel electrodes 2. All segment electrodes and common electrodes are energized.

AC power source 5 is connected to the empty cell, and 20 V, 6
A square wave AC voltage of 4 Hz is applied between the substrates. here,
The threshold value of the liquid crystal cell is 1.7V. The applied voltage value is
It is preferably about 10 times the threshold of the liquid crystal cell.

FIG. 5C is a diagram showing a step of injecting a liquid crystal material between the substrates. With the empty cell still in the high temperature tank 6, a fluorine-type mixed nematic liquid crystal material (N-I phase transition point 98 ° C.) 7 containing a chiral agent is heated, and in an isotropic state, between the opposed substrates. inject. The liquid crystal can be injected between the substrates by a method such as vacuum injection or capillary injection. After the liquid crystal is injected, the liquid crystal injection port is sealed with a sealing material or the like.

FIG. 5 (D) is a diagram showing a process of electrically cooling the liquid crystal cell. A liquid crystal cell in a high temperature state is placed in a high temperature tank 6
Then, it is gradually cooled to a temperature below the phase transition temperature (for example, room temperature) while the electric field is being applied between the substrates by the AC power supply 5. When the liquid crystal material 7 is cooled to the phase transition temperature or lower, it undergoes a phase transition from an isotropic phase to a nematic phase.

The alignment direction of the liquid crystal molecules 7 is determined according to the alignment treatment method of the substrate 1 and the electric field from the AC power supply 9.
When no electric field is applied, the orientation direction is determined only by the substrate orientation treatment method. However, when no electric field is applied, the tilt angle of the liquid crystal molecules 7 is extremely small.

When the liquid crystal cell is gradually cooled while an electric field is applied by the AC power source 9, the liquid crystal molecules 7 are oriented in a standing state. At this time, the tilt angle of the liquid crystal molecules 7 becomes large.

FIG. 6E is a diagram showing a process of removing an electric field. After the liquid crystal material 7 is sufficiently cooled, the AC power source 9 (FIG. 5D) connected between the substrates is disconnected to turn off the electric field. When the electric field is turned off, the tilt angle of the liquid crystal molecules 7 becomes smaller. However, this tilt angle is
As shown in (C), it is larger than that when the liquid crystal molecules are aligned without applying an electric field. Liquid crystal molecules between substrates 7
Is in a uniform alignment state having an appropriate pretilt angle.

The pretilt angle of the liquid crystal molecules 7 between the substrates can be controlled by the electric field condition by the AC power source 9 and the method of aligning the substrate 1. For example, the higher the voltage applied between the substrates, the larger the pretilt angle.

However, if the applied voltage is too small, the pretilt angle does not become so large. On the contrary, if the applied voltage is too large, the twist angle of the twisted nematic liquid crystal layer 7 deviates from the desired one. The applied voltage is preferably about 10 times the threshold voltage of the liquid crystal cell. For example, it is about 2 to 20 times the threshold value. Various frequencies and waveforms can be used. DC may be used instead of AC.

In FIG. 5C, when the liquid crystal material 7 is injected between the substrates, the liquid crystal material 7 may be in the nematic state instead of the isotropic state. In that case, after injecting liquid crystal between the substrates in a nematic state, the liquid crystal cell may be heated to a temperature sufficiently higher than the NI phase transition temperature, and gradually cooled while an electric field is applied between the substrates. When heated to a temperature sufficiently higher than the NI point, the liquid crystal molecules adsorbed on the substrate surface can also move freely and the memory effect can be eliminated.

Further, it is not always necessary to add a chiral agent to the liquid crystal material injected between the substrates. Furthermore, the twist angle of the twisted nematic liquid crystal layer may be larger or smaller than 90 °. You may make it form a super twist nematic liquid crystal layer.

FIG. 7 shows a step of applying a magnetic field instead of applying the electric field of FIG. Between the pair of substrates 1,
Apply a magnetic field H. The magnetic field can be generated, for example, by passing a current through the coil. An empty cell is placed in the high temperature bath 6 in a state where a magnetic field is applied between the substrates. afterwards,
Similarly to the above, if a liquid crystal material is injected between the substrates, cooled, and then the magnetic field is set to 0, liquid crystal molecules having a large pretilt angle are aligned between the substrates.

As with the electric field, various parameters can be used for the magnetic field. When a magnetic field is used, the angle at which the magnetic field is applied can be further controlled arbitrarily, so that the pretilt angle can be adjusted by the application angle of the magnetic field. The magnitude of the magnetic field is preferably about 10 times the threshold magnetic field of the liquid crystal cell, and the direction of the magnetic field is preferably in the range of 0 ° to 45 ° with respect to the substrate normal direction.

In the above, a PVC film is used as the alignment film 3,
Although the case of performing the photo-alignment treatment has been described, other alignment films may be used to perform the alignment treatment in accordance therewith. For example, a rubbing polyimide film, an oblique deposition film, a Langmuir-Blodgett (LB) film, a SiO ₂ film, a stretched polymer film, or the like may be used to form the alignment structure.

The alignment treatment does not necessarily have to be performed on both the pair of substrates. Even when only one of the substrates is subjected to the alignment treatment, the liquid crystal molecules can be uniformly aligned. Further, although the case where the liquid crystal molecules are uniformly aligned has been described, the liquid crystal molecules can be divided and aligned.

FIG. 8 shows a method for producing a substrate having a divided orientation. As a typical example, a case of a two-divided orientation as shown in FIG. 8C will be described as an example. The liquid crystal display device LCD includes a large number of pixels PX arranged in a matrix. Each pixel PX
Is, for example, a rectangle such as a square.
It consists of one sub-pixel area PXa, PXb.

FIG. 8A and FIG. 8B show a process of manufacturing a substrate. First, similarly to the above, the ITO film 2 and the alignment film 3 are formed on the glass substrate 1. However, the alignment film 3 is, for example, a polyimide film. Hereinafter, as the alignment treatment, a rubbing treatment will be described as an example, but other alignment treatments can also be adopted.

Next, a photoresist pattern MK1 is formed on the alignment film 3 so as to cover one sub-pixel region PXa and expose the other sub-pixel region PXb. The photoresist pattern MK1 is formed by applying a general photoresist, for example, OFPR800 manufactured by Tokyo Ohka Kogyo Co., Ltd., onto the substrate by spin coating or roll coating, and removing unnecessary regions by exposure and development.

First, as shown in FIG. 8A, the rubbing roller RR is rubbed on the substrate 1 on which the photoresist film MK1 is formed while rotating the rubbing roller RR in the direction of arrow R1 (clockwise direction). Substrate 1 relative to arrow T1
Then, the alignment film 3 is rubbed.
By this rubbing process, only the exposed region of the alignment film 3 which is not covered with the photoresist film MK1 is rubbed with the direction from right to left in the drawing as the alignment direction.

Next, the photoresist film MK of FIG.
1 is removed and a new photoresist film is applied. As shown in FIG. 8B, the photoresist film is patterned so as to cover the already rubbed sub-pixel region PXb and expose the other sub-pixel regions PXa to form a photoresist pattern MK2.

This time, the rubbing roller RR is rubbed on the substrate 1 while rotating in the opposite direction (counterclockwise direction) indicated by the arrow R2, and the substrate 1 and the rubbing roller RR are relatively moved in the direction indicated by the arrow T2. Then, the alignment film 3 is rubbed. FIG.
In the rubbing step (B), the photoresist pattern M
Only the exposed region of the alignment film 3 which is not covered with K2 is rubbed with the direction from left to right in the drawing as the alignment direction.

Photoresist pattern MK on alignment film 3
When 2 is removed, the two-divided sub-pixel regions PXa whose orientation directions are opposite to each other on the substrate 1 as shown in FIG.
An alignment film 3 having an alignment treatment corresponding to PXb is formed. This completes the substrate for split orientation.

In the case of a pattern in which two sub-pixel regions having different alignment directions are separated from each other by a region that does not require alignment treatment and are spaced apart from each other, the region that does not require alignment treatment is covered with a photoresist pattern. It is also possible to change the orientation direction only by controlling the rotation direction of the rubbing roller RR for each sub-pixel area. In this case, the photoresist pattern need only be formed once.

Further, if the position control accuracy of the rubbing area by the rubbing roller RR is considerably high, it is possible to directly perform the split orientation process by controlling the position of the rubbing roller RR without using the photoresist pattern.
Of course, the rubbing treatment may be performed by rubbing the alignment film 3 by means other than the rubbing roller RR.

A 4-divisional orientation such as shown in FIG.
It is not limited to the divisional alignment, and more multi-divided alignment may be performed, or the alignment structure of the substrate may be produced by using an alignment treatment method other than rubbing.

[0059]

EXAMPLE An alignment structure was formed with a light polarization memory film according to the steps shown in FIGS. 1A to 6E, and a liquid crystal display device using a fluorine-type mixed liquid crystal material containing a chiral agent was manufactured. . No divisional alignment treatment was performed. The surface of the produced liquid crystal cell was observed with a polarization microscope. The liquid crystal molecules between the substrates were observed as a uniform alignment state. As a result of observing the liquid crystal cell with a polarization microscope after turning on the liquid crystal cell, no reverse tilt disclination line was found,
A beautiful display screen was obtained. This also indicates that a large pretilt angle was obtained at the same time.

Next, an anti-parallel liquid crystal display device of 5 μm was prepared by using a fluorine-type mixed liquid crystal material containing no chiral agent. The pretilt angle of this liquid crystal cell was measured by the crystal rotation method. As a result, a large pretilt angle of 0.6 to 1.6 ° was measured.

On the other hand, when the liquid crystal material is injected and the phase transition is performed without applying an electric field, the pretilt angle is 0.1 to 0.1.
Only about 0.3 ° was obtained. Further, when this liquid crystal cell was turned on and observed, many reverse tilt disclination lines were generated immediately after the liquid crystal cell was turned on.

The optimum pretilt angle is about 1 to 3 ° for the twisted nematic liquid crystal layer and about 4 to 10 ° for the super twisted nematic liquid crystal layer. The crystal rotation method used in this measurement is that the liquid crystal cell is arranged at a 45 ° azimuth between the deflectors of the orthogonal Nicols, and the transmitted light intensity changes when the liquid crystal cell is rotated by placing the axis in the substrate plane. This is a method of measuring the pretilt angle.

As described above, when the liquid crystal material is injected between the substrates, an electric field or magnetic field is applied between the substrates to cause the liquid crystal material to undergo a phase transition from the isotropic phase to the nematic phase, thereby increasing the pretilt angle. it can. Specifically, the pretilt angle is determined by the applied voltage, the applied magnetic field strength, and the applied angle of the magnetic field.

Further, even in an alignment process such as a photo-alignment process in which it is difficult to obtain a large pretilt angle as compared with the rubbing alignment process, a large pretilt angle can be obtained by controlling the electric field or magnetic field. A larger pretilt angle can be imparted by applying it when performing rubbing alignment treatment.

According to this embodiment, since a liquid crystal cell having a large pretilt angle can be manufactured, the rising direction of liquid crystal molecules is uniquely determined, and uniform display can be performed. By providing a large pretilt angle, the reverse tilt disclination line does not occur even when the voltage applied to the liquid crystal cell changes abruptly, so that the display quality is improved.

If photo-alignment treatment or the like is used, it is not necessary to perform rubbing alignment treatment, so that TFT (thin film transistor)
And active elements such as MIM (metal insulator metal diode) without electrostatic damage due to rubbing.
LCDs can be made. It is possible to prevent characteristic deterioration and dielectric breakdown due to static electricity, and prevent deterioration of the display quality of the LCD.

The LCD of multi-divided orientation has excellent visual characteristics and can perform high-quality display. In particular, a split-orientation LCD with four or more splits has the same visual characteristics when viewed from any direction.

It is obvious to those skilled in the art that the configurations, materials and the like of the embodiments described above are merely examples, and the present invention is not limited to these and various modifications, improvements and combinations can be made. Let's do it.

[0069]

According to the present invention, a liquid crystal display device having a large pretilt angle is obtained by causing a liquid crystal material between substrates to undergo a phase transition from an isotropic phase to a liquid crystal phase in a state where an electric field or a magnetic field is applied between the substrates. Can be manufactured. By increasing the pretilt angle, the occurrence of reverse tilt disclination lines on the display screen can be suppressed, and the display quality can be improved.

[Brief description of drawings]

FIG. 1A is a cross-sectional view of an empty cell showing a manufacturing process of the empty cell, and FIG. 1B is a sectional view of the empty cell showing a process of energizing the empty cell at a high temperature.

FIG. 2 is a cross-sectional view of a substrate for explaining a manufacturing process of the substrate.

FIG. 3 is a substrate cross-sectional view showing a configuration example of a substrate having a pixel electrode.

FIG. 4 shows a photo-alignment treatment process. FIG. 4 (A) is a first light irradiation step, FIG. 4 (B) is a second light irradiation step, and FIG. 4 (C) is a diagram for explaining the alignment direction of liquid crystal molecules.

5 (C) is a sectional view showing a step of injecting a liquid crystal material between the substrates, and FIG. 5 (D) is a sectional view showing a step of electrically cooling the liquid crystal cell.

FIG. 6E is a cross-sectional view showing a step of removing an electric field.

FIG. 7 is a cross-sectional view illustrating a method of manufacturing a liquid crystal display device according to another embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating a process of manufacturing a substrate having a two-divided orientation according to an embodiment of the present invention.

FIG. 9 shows a manufacturing process of a conventional liquid crystal display device. 9A is a cross-sectional view for explaining the empty cell manufacturing process, FIG. 9B is a liquid crystal injection process, and FIG. 9C is a cooling process.

[Explanation of symbols]

 1,51 Substrate 2 ITO film 3,53 Alignment film 5 AC power supply 6 High temperature tank 7,57 Liquid crystal material RR Rubbing roller MK Photoresist

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoshi Ando 1-3-1 Eda Nishi, Aoba-ku, Yokohama-shi, Kanagawa Stanley Electric Co., Ltd.

Claims (8)

[Claims] 1. A step of preparing a pair of substrates, at least one of which has been subjected to an alignment treatment, a step of disposing the pair of substrates so as to face each other and injecting a liquid crystal material between the substrates, and an electric field between the substrates. A step of causing a liquid crystal material between the substrates to undergo a phase transition from an isotropic phase to a liquid crystal phase in the applied state. 2. A step of preparing a pair of substrates, at least one of which has been subjected to an alignment treatment, a step of disposing the pair of substrates so as to face each other and injecting a liquid crystal material between the substrates, and applying a magnetic field between the substrates. A step of causing a liquid crystal material between the substrates to undergo a phase transition from an isotropic phase to a liquid crystal phase in the applied state. 3. The step of preparing the pair of substrates comprises a step of forming an optical polarization storage film on the surface of one of the pair of substrates and subjecting the optical polarization storage film to an alignment treatment. The method for manufacturing a liquid crystal display device according to claim 1 or 2, further comprising: 4. The method of manufacturing a liquid crystal display device according to claim 3, wherein the step of performing the alignment treatment is a step of irradiating the optical polarization storage film formed on the substrate surface with polarized light twice or more by changing the irradiation direction. . 5. The method for manufacturing a liquid crystal display device according to claim 3, wherein in the step of forming a light polarization storage film on the surface of the substrate, the light polarization storage film is a polyvinyl cinnamate film. 6. The method for manufacturing a liquid crystal display device according to claim 1, wherein in the step of injecting a liquid crystal material between the substrates, the liquid crystal material contains a chiral agent. 7. The step of subjecting the substrate to an alignment treatment is a step of forming a plurality of regions having different alignment directions.
7. The method for manufacturing a liquid crystal display device according to any one of 6 to 6. 8. The method of manufacturing a liquid crystal display device according to claim 1, wherein the step of preparing the pair of substrates includes a step of forming a transparent conductive film and an alignment film on a glass substrate. .