JPH06337420A - Manufacture of liquid crystal display device - Google Patents

Abstract

(57) [Summary] (Modified) [Object] To provide a liquid crystal display device which is easy to manufacture and has a precise viewing angle by forming an accurate alignment film. [Structure] One substrate is subjected to an alignment treatment having a predetermined pretilt angle 15, and the other substrate is provided with a portion 6 having a pretilt angle lower than the predetermined pretilt angle.
And a portion 4 having a pretilt angle higher than the predetermined pretilt angle are subjected to an alignment treatment arranged in a desired shape, and are aligned while forming a spiral structure in a predetermined direction defined by the pretilt angle. A panel,
In a liquid crystal display device in which a nematic liquid crystal having a twisting force that takes a spiral structure opposite to a predetermined direction is enclosed between two substrates, a polymer alignment film is formed on the other substrate, and after rubbing treatment is performed. By irradiating ultraviolet light through a mask having a predetermined pattern, the pretilt angle of the alignment film is partially changed to a non-irradiated portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display device for displaying an image, and more particularly to a method of manufacturing a liquid crystal display device having a wider viewing angle than conventional ones.

[0002]

2. Description of the Related Art Among liquid crystal display devices, in recent years, in order to obtain an image with particularly high display quality, active matrix drive type display devices using thin film transistors as switching elements have been actively developed. This is because a high contrast ratio can be obtained regardless of the number of scanning electrodes as compared with a simple matrix driving method without a switching element, and thus a clear image can be obtained even in large-capacity display with high resolution.

In such an active matrix type liquid crystal display device, a TN (Twisted Nematic) type NW (Normally) liquid crystal display mode is widely used.
White) mode. The TN method consists of two polarizing plates sandwiching a liquid crystal panel in which liquid crystal molecules are twisted 90 ° between substrates. In the NW mode, the polarizing axes of the two polarizing plates are orthogonal to each other, and the polarizing axis of one polarizing plate is parallel or perpendicular to the major axis direction of the liquid crystal molecules in contact with one substrate. Are arranged as follows.

In the TN mode NW mode, no voltage is applied or white display is performed at a low voltage near the threshold voltage, and when a voltage higher than that is applied, the light transmittance gradually decreases and black appears. Will be displayed. Such display characteristics are obtained because when a voltage is applied to the liquid crystal panel, the liquid crystal molecules try to align themselves in the direction of the electric field while untwisting the twisted structure. This is because the polarization state of is changed and the light transmittance is modulated. By the way, even in the state of the same molecular arrangement, the polarization state of transmitted light changes depending on the incident direction of light incident on the liquid crystal panel, so that the light transmittance varies depending on the incident direction. That is, the characteristics of the liquid crystal panel have a viewing angle dependency.

This viewing angle dependence has the following features. In the case of the NW mode, it is remarkable in the vicinity of black display in which liquid crystal molecules stand up with respect to the substrate by applying a voltage. Then, the viewing angle dependency at that time has a characteristic that it includes the major axis direction of the liquid crystal molecules near the center of the liquid crystal layer and is substantially symmetrical with respect to a plane perpendicular to the substrate. However, it is asymmetric with respect to a ray having a traveling direction in this plane, and the transmittance significantly changes depending on the angle of incidence on the substrate, so that the viewing angle characteristics change greatly in this direction. In the normal driving voltage range, the liquid crystal molecules do not rise completely perpendicularly to the substrate surface, so that the asymmetry of the viewing angle characteristics remains and the NW mode TN
It narrows the viewing angle of the panel. The major axis direction of the liquid crystal molecules near the center of the liquid crystal layer is generally called the main viewing angle direction,
In this direction, the transmittance becomes the lowest at a low voltage as compared with the case of being viewed from other directions.

Generally, the screens shown in FIGS.
As shown in FIG. 0, rubbing alignment treatment is performed on the front substrate 31 in the direction of arrow 32 and on the opposing substrate 33 in the direction of arrow 34. Reference numeral 35 indicates the vertical direction. Since the liquid crystal molecules 36 have a pretilt angle 38 with respect to the rubbing direction 37 as shown in FIG. 10, the major axis direction of the liquid crystal molecules near the center of the liquid crystal layer is
The lines are aligned in a plane perpendicular to the substrates 31 and 33, and therefore, the direction in which the change in the viewing angle characteristics is large is the vertical direction 35 of the screen, which is symmetrical with respect to the left and right. Reference numeral 39 indicates an alignment film. That is, the viewing angle characteristics of the light transmittance of this panel when a voltage is applied (when displaying black) are asymmetric in the vertical direction as shown in FIG.

As a method for solving the asymmetry of the vertical viewing angle characteristics and improving the viewing angle characteristics, the inventors have proposed the following liquid crystal display device (Japanese Patent Application No. 4-262).
2). This is because the minute areas having either the upward or downward main viewing angle direction are formed close to each other in the panel, and the viewing angle characteristics are compensated for each other, thereby eliminating the asymmetry of the vertical viewing angle characteristics and symmetry. It is intended to obtain a wide viewing angle characteristic. As a method for manufacturing such a liquid crystal display device, the inventors have applied a method of separately coating alignment films having different pretilt angles of liquid crystal by a printing method and applying a photoresist on the alignment film,
We proposed a method to change the pretilt angle by patterning the alignment film in the photolithography process.

[0008]

However, the method of separately coating the alignment films having different pretilt angles by the printing method has a problem that the dimensional accuracy and the positioning accuracy are poor and it is difficult to cope with high-definition display. The method of applying a photoresist on the alignment film and patterning the alignment film by a photolithography process to change the pretilt angle can be applied to high-definition display, but there is a problem that the process is complicated and the process cost becomes high. Further, deterioration of liquid crystal alignment characteristics due to process damage to the alignment film surface is also a problem. Further, in these methods, it is necessary to use three types of alignment films having different pretilt angles, and there is a problem that the process of applying the alignment film becomes complicated.

An object of the present invention is to solve the above problems, to realize a pretilt region patterning method which can be easily manufactured and has excellent dimensional accuracy, and to provide a manufacturing method of a liquid crystal display device having symmetrical viewing angle characteristics. Is what you are trying to do.

[0010]

In order to achieve the above object, in the first invention, one substrate is subjected to an alignment treatment having a predetermined pretilt angle, and the other substrate is subjected to an alignment treatment more than the predetermined pretilt angle. A portion having a low pretilt angle and a portion having a pretilt angle higher than the predetermined pretilt angle are arranged in a desired shape and subjected to alignment treatment, and between the two substrates. In the nematic liquid crystal material having no twisting force, the liquid crystal panel is oriented while taking a spiral structure in a predetermined direction defined by the pretilt angle, and the liquid crystal panel has a spiral structure opposite to the predetermined direction. In a manufacturing process of a liquid crystal display device in which a nematic liquid crystal having such a twisting force is sealed, a polymer alignment film is formed on the other substrate and a rubbing treatment is performed. After becoming, by irradiating ultraviolet light through a mask having a predetermined pattern, and a method for producing a liquid crystal display device having a step of changing a partially non-irradiated portion pretilt angle of the alignment layer.

According to the second aspect of the invention, in the manufacturing process of the liquid crystal display device, a polymer alignment film is formed on the other substrate and irradiated with ultraviolet light through a mask having a predetermined pattern.
By performing the rubbing process, the pretilt angle of the alignment film is partially changed from the non-irradiated portion. In the third invention,
Polymer alignment film made of the same material is formed on both substrates,
One surface of the substrate is irradiated with ultraviolet light, and the other substrate is irradiated with ultraviolet light through a mask having a predetermined pattern.

In the fourth invention, after irradiating with ultraviolet light, the surface of the alignment film is treated with a solvent. In the fifth invention, a polyimide material is used as the polymer alignment film.

[0013]

According to the first aspect of the present invention, in the alignment film forming step, the alignment film of either one of the substrates is irradiated with ultraviolet light through an appropriate photomask, whereby an ultraviolet light irradiation portion and a non-irradiation portion are formed. The value of the pretilt angle can be made different. It is considered that this is because the irradiation with ultraviolet rays causes some chemical reaction such as a crosslinking reaction or an oxidation reaction on the polymer surface of the alignment film, thereby changing the interaction with the liquid crystal. Generally, when the surface energy of the alignment film becomes high,
It is known that the pretilt angle of liquid crystal tends to be small. It is considered that when the cross-linking reaction or the oxidation reaction occurs on the polymer surface of the alignment film by the irradiation of ultraviolet light, the surface energy increases and the pretilt angle decreases. This makes it possible to manufacture a liquid crystal display with a wide viewing angle range very easily, at low cost, and without causing alignment deterioration.

In the second invention, since the rubbing treatment is performed after the irradiation of ultraviolet light, the change in the pretilt angle becomes more apparent. In the third invention, the change of the pretilt angle is formed by changing the irradiation of ultraviolet light. Further, in the fourth invention, the surface of the alignment film is treated with a suitable solvent after irradiation with ultraviolet light, whereby the surface is further modified, and the change in pretilt angle due to irradiation with ultraviolet light can be further increased.

[0015]

EXAMPLES Examples of the method for manufacturing a liquid crystal display device of the present invention will be described below. The present invention, as shown in FIG.
The liquid crystal panel in which the vertical viewing angle characteristics are compensated is realized by controlling the pretilt angle of the liquid crystal on the upper and lower substrate surfaces. FIG. 1 shows a cross-sectional view of this liquid crystal display device.
One substrate 1A, the other substrate 1B, and one substrate 1A
And transparent electrodes 2A, 2 provided on the inner surface of the other substrate 1B
B, an alignment film 3 provided on the inner surface of the panel on the transparent electrode 2A, an alignment film 5 having a pretilt angle 4 larger than that of the alignment film 3 provided on the transparent electrode 2B, and provided on the transparent electrode 2B. The alignment film 7 has a pretilt angle 6 smaller than that of the alignment film 3 and liquid crystal molecules 9. And 1
Reference numeral 0 denotes the central portion of the liquid crystal layer, 11 denotes the liquid crystal molecule pretilt φ1 at the central portion of the liquid crystal layer, 12 denotes the liquid crystal molecule pretilt φ2 at the central portion of the liquid crystal layer, 13 denotes the upper viewing angle direction, and 14 denotes the lower viewing angle direction.

In the above structure, one substrate 1A is subjected to an alignment treatment so as to have a pretilt angle 15 of θ, and the other substrate 1B is subjected to a pretilt angle 4 of θ + φ1 and θ-φ.
It has two pre-tilt angles of 6 (φ1> 0, θ>φ2> 0) and two alignment treatment regions. When such an alignment treatment is performed, the liquid crystal molecules 9 in the central portion 10 of the liquid crystal layer in the region having the pretilt angle of θ + φ1 have the pretilt 11 of about φ1 and in the region having the pretilt angle 4 of θ−φ2. The liquid crystal molecules 9 in the central portion 10 of the liquid crystal layer are oriented so as to have a pretilt 12 of an angle of about -φ2.

Therefore, when a voltage is applied to this liquid crystal panel, the main viewing angle has the characteristic of the downward direction 14 in the region where the liquid crystal molecules 9 in the central portion 10 of the liquid crystal layer had the pretilt 12 of an angle of about -φ 2. In a region where the liquid crystal molecules 9 in the central portion 10 of the layer have a pretilt 11 of an angle of about φ1, the main viewing angle has a characteristic of an upper viewing angle 13. In this way, when the regions having both the upper and lower viewing angle characteristics are arranged closer to each other than the resolution that a human sees, the viewing angle characteristics of the liquid crystal panel are a combination of the characteristics of the two regions, and the normal to the substrate in the vertical direction as well. It is possible to obtain a substantially symmetrical characteristic as shown in FIG. 5 about the direction.

In the present invention, ultraviolet light is used as a method for producing a liquid crystal panel having such a structure. As the alignment film, a polymer rubbing film is preferable from the viewpoint of easy production, but an inorganic vapor deposition film or the like can be used on the substrate side that does not require pretilt patterning. It is known that among polymer materials, those having a high glass transition temperature and a chain-like molecular structure are generally suitable as a liquid crystal alignment film. Also in the present invention, basically, if such a condition is satisfied, the polymer can be used as an alignment film polymer. For example, examples of the polymer material that can be used as the alignment film include polyester, polysulfone, polyamide, polyimide, polyamideimide, polyesterimide, poly (p-xylene), phenoxy resin, polyphenylene oxide, polyphenylene sulfide, polyphenylene, and polyphenylene. Examples include benzimidazole, polyamine and polyimine. Of these, polyimide is particularly preferable as an alignment film material because it is easy to form a film and has excellent reliability.

Hereinafter, a specific method for manufacturing the liquid crystal display device of the present invention will be described with reference to FIGS.

Example 1 First, a JALS-199 polyimide alignment film manufactured by Japan Synthetic Rubber Co., Ltd. was offset-printed on one substrate 1A made of glass on which transparent row electrodes 2A were formed. The alignment film is formed uniformly on the entire screen by this printing.

Next, on the other substrate 1B on which the transparent column electrodes 2B are formed, a polyimide J made by Nippon Synthetic Rubber Co., Ltd. is also used.
ALS-194 was printed. After heating both substrates at 180 ° C. for 30 minutes, a row electrode substrate (one substrate) 1A and a column electrode substrate (other substrate) 1B are rubbed with rayon cloth in directions 16 and 17 as shown in FIG. 2, respectively. Was applied.
18 indicates a spiral.

Next, the substrate 1B was irradiated with ultraviolet light from a high-pressure mercury lamp using the photomask 19 patterned in stripes at a pitch of 200 μm as shown in FIG. The irradiation energy was 55 mW / cm ² and the irradiation time was 5 minutes. As a result, as shown in FIG. 4, the light irradiation region 20 and the non-irradiation region 21 were formed in stripes with a width of approximately 100 μm.

The row electrode substrate 1A and the column electrode substrate 1B were bonded to each other so that the electrodes 2A and 2B face each other. When a nematic liquid crystal having no twisting force is injected into a panel subjected to such an alignment treatment, the counterclockwise spiral 18 is picked up, and the orientation becomes more stable in terms of energy due to the influence of pretilt. To such a panel, a liquid crystal material ZLI-4792 manufactured by Merck & Co., Ltd. was added with a chiral material R-811 having a clockwise twisting force, and a liquid crystal prepared so that a chiral pitch was about 80 μm was injected. .

In order to know the pretilt angle in the case of using the above alignment film material and liquid crystal material, measurement by the crystal rotation method was performed. For the measurement, the same alignment film was applied, and two transparent substrates that had been rubbed were used to measure the cell thickness 2
A cell for measurement was used in which the cells were bonded so as to have a homogeneous orientation at 0 μm and a liquid crystal material was injected. As a result of the measurement,
JALS-199 has a pre-tilt angle of about 3 °, JALS-
If you do not irradiate 194 with ultraviolet light, about 5 °, JALS-
It was found to be about 1 ° when 194 was irradiated with ultraviolet light under the above conditions. That is, it was confirmed that the liquid crystal orientation of the panel manufactured by the manufacturing method of the present example has the configuration shown in FIG.

Polarizing plates were attached to both sides of the liquid crystal panel manufactured as described above so as to form a crossed nicols to obtain a liquid crystal display device. When a voltage was applied to this liquid crystal panel and the viewing angle dependence on the transmittance in the vertical direction of the panel was measured, it showed the characteristics shown in FIG. 5 and was symmetrical in the vertical direction with respect to the substrate normal line of the panel. The characteristics could be obtained.

Example 2 First, a JALS-199 polyimide alignment film manufactured by Japan Synthetic Rubber Co., Ltd. was offset-printed on one glass substrate 1A on which transparent row electrodes 2A were formed. The alignment film is formed uniformly on the entire screen by this printing.

Next, on the other substrate 1B on which the transparent column electrodes 2B are formed, a polyimide J made by Nippon Synthetic Rubber Co., Ltd. is also used.
ALS-194 was printed. After heating both substrates at 180 ° C. for 30 minutes, a row electrode substrate (one substrate) 1A and a column electrode substrate (other substrate) 1B are rubbed with rayon cloth in directions 16 and 17 as shown in FIG. 2, respectively. Was applied.

Then, the substrate 1B was irradiated with ultraviolet light from a low-pressure mercury lamp using the photomask 19 patterned in stripes at a pitch of 200 μm as shown in FIG. The irradiation energy was 27 mW / cm ² and the irradiation time was 1 minute. As a result, the light irradiation region 20 and the non-irradiation region 21 were formed in stripes with a width of about 100 μm as shown in FIG.

The row electrode substrate 1A and the column electrode substrate 1B were bonded to each other so that the electrodes 2A and 2B face each other. When a nematic liquid crystal having no twisting force is injected into a panel subjected to such an alignment treatment, the counterclockwise spiral 18 is picked up, and the orientation becomes more stable in terms of energy due to the influence of pretilt. To such a panel, a liquid crystal material ZLI-4792 manufactured by Merck & Co., Ltd. was added with a chiral material R-811 having a clockwise twisting force, and a liquid crystal prepared so that a chiral pitch was about 80 μm was injected. .

In order to know the pretilt angle in the case of using the above alignment film material and liquid crystal material, the measurement by the crystal rotation method was performed. For the measurement, the same alignment film is applied and two rubbing-processed transparent substrates are attached to each other so as to have a homogeneous alignment with a cell thickness of 20 μm.
A measurement cell filled with a liquid crystal material was used. As a result of measurement, JALS-199 has a pretilt angle of about 3 °,
About 5 ° when S-194 is not irradiated with UV light, JAL
Approximately 1 ° when S-194 is irradiated with UV light under the above conditions
It turned out to be That is, it was confirmed that the liquid crystal orientation of the panel manufactured by the manufacturing method of the present example has the configuration shown in FIG.

Polarizing plates were attached to both sides of the liquid crystal panel manufactured as described above so as to form a crossed Nicols, whereby a liquid crystal display device was obtained. When a voltage was applied to this liquid crystal panel and the viewing angle dependence on the transmittance in the vertical direction of the panel was measured, it showed the characteristics shown in FIG. 5 and was symmetrical in the vertical direction with respect to the substrate normal line of the panel. The characteristics could be obtained.

Example 3 First, a JALS-199 polyimide alignment film manufactured by Japan Synthetic Rubber Co., Ltd. was offset-printed on one glass substrate 1A on which transparent row electrodes 2A were formed. The alignment film is formed uniformly on the entire screen by this printing.

Next, on the other substrate 1B on which the transparent column electrodes 2B are formed, a polyimide J manufactured by Nippon Synthetic Rubber Co., Ltd. is also used.
ALS-194 was printed. Both substrates were heated at 180 ° C. for 30 minutes. Then, the substrate 1B was irradiated with ultraviolet light from an ultra-high pressure mercury lamp using a photomask 19 patterned in a stripe shape at a pitch of 200 μm as shown in FIG. The irradiation energy was 55 mW / cm ² and the irradiation time was 5 minutes. As a result, the light-irradiated region 5 and the non-irradiated region 7 were formed in stripes with a width of about 100 μm as shown in FIG. With rayon cloth on these substrates,
The row electrode substrate (one substrate) 1A and the column electrode substrate (other substrate) 1B were rubbed in directions 16 and 17 as shown in FIG. 2, respectively.

The row electrode substrate 1A and the column electrode substrate 1B were attached to each other so that the electrodes 2A and 2B face each other. When a nematic liquid crystal having no twisting force is injected into a panel subjected to such an alignment treatment, the counterclockwise spiral 18 is picked up, and the orientation becomes more stable in terms of energy due to the influence of pretilt. To such a panel, a liquid crystal material ZLI-4792 manufactured by Merck & Co., Ltd. was added with a chiral material R-811 having a clockwise twisting force, and a liquid crystal prepared so that a chiral pitch was about 80 μm was injected. .

In order to know the pretilt angle when the above alignment film material and liquid crystal material are used, measurement by the crystal rotation method was performed. For the measurement, the same alignment film is applied and two rubbing-processed transparent substrates are attached to each other so as to have a homogeneous alignment with a cell thickness of 20 μm.
A measurement cell filled with a liquid crystal material was used. As a result of measurement, JALS-199 has a pretilt angle of about 3 °,
About 5 ° when S-194 is not irradiated with UV light, JAL
Approximately 1 ° when S-194 is irradiated with UV light under the above conditions
It turned out to be That is, it was confirmed that the liquid crystal orientation of the panel manufactured by the manufacturing method of this example had the configuration shown in FIG.

Polarizing plates were attached to both sides of the liquid crystal panel manufactured as described above so as to form a crossed nicols to obtain a liquid crystal display device. A voltage was applied to this liquid crystal panel, and the viewing angle dependence of the transmittance in the vertical direction of the panel was measured. As a result, similar to Example 1, the characteristics as shown in FIG. It was possible to obtain symmetrical characteristics in the vertical direction.

Even when the rubbing alignment treatment was performed after the irradiation of the ultraviolet light as in this example, almost the same result as the irradiation of the ultraviolet light after the rubbing was obtained.

Example 4 First, a JALS-194 polyimide alignment film manufactured by Japan Synthetic Rubber Co., Ltd. was offset-printed on one substrate 1A made of glass on which transparent row electrodes 2A were formed. The alignment film is formed uniformly on the entire screen by this printing.

Next, on the other substrate 1B on which the transparent column electrodes 2B are formed, a polyimide J made by Nippon Synthetic Rubber Co., Ltd. is also used.
ALS-194 was printed. Both substrates were heated at 180 ° C. for 30 minutes. Then, the substrate 1A was irradiated with ultraviolet light from a high pressure mercury lamp. The irradiation energy was 55 mW / cm ² and the irradiation time was 3 minutes. Furthermore, as shown in FIG.
Using a photomask 19 patterned in stripes at a pitch of μm, the substrate 1B was irradiated with ultraviolet light from a high pressure mercury lamp. Irradiation energy is 55 mW / cm ²
The irradiation time was 5 minutes. As a result, the light irradiation area 20 and the non-irradiation area 21 are almost 100 μm as shown in FIG.
It was formed in a stripe shape with a width of m. These substrates were rubbed with a rayon cloth on the row electrode substrate (one substrate) 1A and the column electrode substrate (other substrate) 1B in directions 16 and 17 as shown in FIG.

The row electrode substrate 1A and the column electrode substrate 1B were bonded to each other so that the electrodes 2A and 2B face each other. When a nematic liquid crystal having no twisting force is injected into a panel subjected to such an alignment treatment, the counterclockwise spiral 18 is picked up, and the orientation becomes more stable in terms of energy due to the influence of pretilt. To such a panel, a liquid crystal material ZLI-4792 manufactured by Merck & Co., Ltd. was added with a chiral material R-811 having a clockwise twisting force, and a liquid crystal prepared so that a chiral pitch was about 80 μm was injected. .

In order to know the pretilt angle in the case of using the above alignment film material and liquid crystal material, measurement by the crystal rotation method was performed. For the measurement, the same alignment film is applied and two rubbing-processed transparent substrates are attached to each other so as to have a homogeneous alignment with a cell thickness of 20 μm.
A measurement cell filled with a liquid crystal material was used. As a result of the measurement, when the JALS-194 is not irradiated with ultraviolet light, it is about 5
It was found that the temperature was about 3 ° when irradiated with ultraviolet light for 3 minutes, and about 1 ° when irradiated with ultraviolet light for 5 minutes. That is,
It was confirmed that the liquid crystal orientation of the panel manufactured by the manufacturing method of the present example had the configuration shown in FIG.

Polarizing plates were attached to both sides of the liquid crystal panel manufactured as described above so as to form a crossed nicols to obtain a liquid crystal display device. When a voltage was applied to this liquid crystal panel and the viewing angle dependence of the transmittance in the vertical direction of the panel was measured, the characteristics shown in FIG. 5 were exhibited, and the characteristics were symmetrical in the vertical direction with respect to the panel normal to the panel. I was able to get

By appropriately controlling the irradiation energy of ultraviolet light as in this example, the pretilt angle can be changed and the intended liquid crystal display device can be obtained by using only one kind of alignment film material. It could be confirmed.

Example 5 First, a JALS-199 polyimide alignment film manufactured by Japan Synthetic Rubber Co., Ltd. was offset printed on one substrate 1A made of glass on which transparent row electrodes 2A were formed. The alignment film is formed uniformly on the entire screen by this printing.

Next, on the other substrate 1B on which the transparent column electrodes 2B are formed, a polyimide J made by Nippon Synthetic Rubber Co., Ltd. is also used.
ALS-194 was printed. After heating both substrates at 180 ° C. for 30 minutes, a row electrode substrate (one substrate) 1A and a column electrode substrate (other substrate) 1B are rubbed with rayon cloth in directions 16 and 17 as shown in FIG. 2, respectively. Was applied.

Next, the substrate 1B was irradiated with ultraviolet light from a high-pressure mercury lamp using the photomask 17 patterned in stripes at a pitch of 200 μm as shown in FIG. The irradiation energy was 55 mW / cm ² and the irradiation time was 3 minutes. As a result, the light irradiation region 20 and the non-irradiation region 21 were formed in stripes with a width of about 100 μm as shown in FIG. Substrate 1B was immersed in isopropyl alcohol and dried at 120 ° C. for 30 minutes.

The row electrode substrate 1A and the column electrode substrate 1B were bonded to each other so that the electrodes 2A and 2B face each other. When a nematic liquid crystal having no twisting force is injected into a panel subjected to such an alignment treatment, the counterclockwise spiral 18 is picked up, and the orientation becomes more stable in terms of energy due to the influence of pretilt. To such a panel, a liquid crystal material ZLI-4792 manufactured by Merck & Co., Ltd. was added with a chiral material R-811 having a clockwise twisting force, and a liquid crystal prepared so that a chiral pitch was about 80 μm was injected. .

In order to know the pretilt angle in the case of using the above alignment film material and liquid crystal material, measurement by the crystal rotation method was performed. In the measurement, a measurement cell in which the same alignment film was applied and two rubbing-processed transparent substrates were attached to each other so as to have a homogeneous alignment with a cell thickness of 20 μm and a liquid crystal material was injected was used. As a result of the measurement, JALS-199 has a pretilt angle of about 3 °, and JALS-194 treated with isopropyl alcohol
It was found that it was about 5 ° when not irradiated with ultraviolet light, and about 1 ° when irradiated with ultraviolet light. By treating with isopropyl alcohol, a large pretilt change could be achieved by irradiation with ultraviolet light for a shorter time.

It was confirmed that the liquid crystal orientation of the panel manufactured by the manufacturing method of this example had a structure as shown in FIG. Polarizing plates were attached to both sides of the liquid crystal panel manufactured as described above so as to form a crossed Nicols, whereby a liquid crystal display device was obtained. When a voltage was applied to this liquid crystal panel and the viewing angle dependence on the transmittance in the vertical direction of the panel was measured, it showed the characteristics shown in FIG. 5 and was symmetrical in the vertical direction with respect to the substrate normal line of the panel. The characteristics could be obtained.

In this embodiment, isopropyl alcohol was used as the treatment solvent, but alcohol solvents such as methanol, ethanol, propanol and butanol, ether solvents such as diethyl ether and methyl ethyl ether, and ketones such as acetone and methyl ethyl ketone. A system solvent, a halogen solvent such as dichloromethane, chloroform, and dichloroethane, and a polar solvent such as water (warm water) are effective in changing the pretilt angle.

One of the substrates is subjected to an alignment treatment having a predetermined pretilt angle, and the other substrate is provided with a portion having a pretilt angle lower than the predetermined pretilt angle.
In order to obtain a liquid crystal panel having a portion having a pretilt angle higher than the predetermined pretilt angle, it is necessary to use two kinds of alignment film materials only by irradiating one substrate with ultraviolet light. The alignment film formed on one substrate is irradiated with ultraviolet light over the entire surface, and the alignment film formed on the other substrate is exposed to ultraviolet light having a stronger surface modification effect through a mask having a predetermined pattern. By performing the irradiation of 1), it becomes possible to achieve the required pretilt relationship using the same alignment film material.

(Embodiment 6) Next, another embodiment of the present invention will be described with reference to FIGS.

First, an alignment film JALS-199 was offset-printed on a glass substrate (one substrate) 1A 'on which transparent electrodes were formed. The alignment film was uniformly formed on the entire screen by this printing. Next, the picture elements 22 are arranged in a matrix.
Similarly, on the active matrix array substrate 1B ′ in which the thin film transistor elements 23 are formed in each picture element 22, the JALS-194 alignment film 24 is similarly printed on the entire screen. Both of these substrates were heated at 190 ° C. for 30 minutes to cure the alignment film. Then, the electrode substrate and the active matrix array substrate 1B ′ were rubbed with rayon cloth in directions 27 and 28 shown in FIG. 7, respectively.

Further, as shown in FIG. 6C, a mask 26 in which the upper half of each pixel 22 on the substrate is shielded is used for the JALS-194 orientation film 24 formed on the active matrix array substrate 1B '. And exposed to ultraviolet light. The ultraviolet light emitted from the ultra-high pressure mercury lamp was 55 mW / cm ²
The irradiation time was 5 minutes. Through these steps, a light non-irradiated region 29 is formed in the upper half of the picture element as shown in FIG.
However, a light irradiation region 30 was formed on the surface of the active matrix substrate 1B ′ in the lower half of the picture element. Both these boards,
The electrodes were attached so that the electrode sides face each other. The pretilt angle on the surface of each alignment film is as described in Example 1.

To such a panel, a liquid crystal material ZLI-4792 manufactured by Merck & Co., Ltd. was added with a chiral material R-811 having a clockwise twisting force to obtain a chiral pitch of about 8.
A liquid crystal prepared to have a thickness of 0 μm was injected. Polarizing plates were attached to both sides of the liquid crystal panel manufactured as described above so as to form a crossed Nicols, whereby a liquid crystal display device was obtained. By applying a voltage to this liquid crystal panel and measuring the viewing angle dependence on the transmittance in the vertical direction of the panel,
The same viewing angle characteristics as in Example 1 could be obtained, and the asymmetry of the vertical viewing angle characteristics could be eliminated.

Further, when this liquid crystal display device was incorporated into a projector and an image was enlarged and projected on a screen, a uniform and excellent display could be obtained. In the active matrix type liquid crystal display panel, the display performance is degraded unless the impedance of the panel is high. It is known that the influence of the alignment film is large on the impedance of the panel, but in the method for manufacturing the liquid crystal display device of the present invention, the deterioration of the impedance of the panel is hardly caused by the irradiation of ultraviolet light, and the high impedance is maintained. it can. Therefore, the liquid crystal display device manufactured by the present manufacturing method is not only excellent in viewing angle characteristics, but also does not cause a decrease in contrast or display unevenness, and has a very high display quality.

[0057]

As described above, according to the method of manufacturing a liquid crystal display device of the present invention, the pretilt angle can be controlled by irradiating with ultraviolet light, and between the adjacent minute regions of the liquid crystal panel,
It is possible to easily manufacture a liquid crystal panel that has been subjected to an alignment treatment so as to have opposite viewing angle characteristics in the vertical direction. This makes it possible to make the viewing angle characteristics in the vertical direction of the panel almost symmetrical in any part of the screen, and thus to manufacture a stable, high-quality liquid crystal display device without uneven brightness in the screen. Became possible.

[Brief description of drawings]

FIG. 1 is a structural cross-sectional view showing the alignment of liquid crystal molecules of a liquid crystal display device manufactured by the present invention.

FIG. 2 is a plan view showing a rubbing processing direction in Examples 1 to 5;

FIG. 3 is a plan view showing a part of a photomask used in Examples 1 to 5.

FIG. 4 is a plan view showing patterns of an ultraviolet light irradiation region and a non-irradiation region formed in Examples 1 to 5.

FIG. 5 is a view angle characteristic diagram of light transmittance when a voltage is applied to the liquid crystal display device manufactured in Example 1 of the present invention.

6 (a), (b), (c), and (d) are process diagrams of forming each alignment film in Example 6.

FIG. 7 is a plan view showing the rubbing processing direction in the sixth embodiment.

FIG. 8 is a plan view showing a rubbing processing direction in a conventional liquid crystal display device.

FIG. 9 is a view angle characteristic diagram of light transmittance when a voltage is applied to a conventional liquid crystal display device.

FIG. 10 is an explanatory diagram of a relationship between a rubbing direction and an alignment direction of liquid crystal molecules in a liquid crystal display device.

[Explanation of symbols]

 1A, 1A 'One substrate 1B, 1B' Other substrate 2A, 2B Transparent electrode 3, 5, 7 Alignment film 4, 6, 15 Pretilt angle 18 Spiral

Claims (5)

[Claims] 1. One of the substrates is subjected to an alignment treatment having a predetermined pretilt angle, and the other substrate is provided with a portion having a pretilt angle lower than the predetermined pretilt angle and the predetermined pretilt angle. And a portion having a high pretilt angle are arranged in a desired shape and subjected to alignment treatment, and a nematic liquid crystal material having no twisting force between the two substrates is defined by the pretilt angle. A liquid crystal panel which is oriented while having a spiral structure in a predetermined direction, wherein a nematic liquid crystal having a twisting force having a spiral structure opposite to the predetermined direction is enclosed in the liquid crystal panel. In the manufacturing process of, the polymer alignment film is formed on the other substrate, and after rubbing treatment, ultraviolet light is passed through a mask having a predetermined pattern. And a step of partially changing the pretilt angle of the alignment film to a non-irradiated portion by irradiating the liquid crystal display device. 2. The process of manufacturing a liquid crystal display device according to claim 1, wherein a polymer alignment film is formed on the other substrate, and ultraviolet rays are radiated through a mask having a predetermined pattern, followed by rubbing treatment. A method for manufacturing a liquid crystal display device, comprising the step of partially changing the pretilt angle of the alignment film to a non-irradiated portion by carrying out. 3. A process for manufacturing a liquid crystal display device according to claim 1, wherein a polymer alignment film made of the same material is formed on both substrates, one substrate is irradiated with ultraviolet light, and the other substrate is irradiated. 3. The method for manufacturing a liquid crystal display device according to claim 1, further comprising the step of irradiating ultraviolet light through a mask having a predetermined pattern. 4. The method according to claim 1, further comprising the step of treating the surface of the alignment film with a solvent after irradiating with ultraviolet light.
Or the method for manufacturing the liquid crystal display device according to item 3. 5. The method for manufacturing a liquid crystal display device according to claim 1, wherein the polymer alignment film is a polyimide material.