JPH03287230A - Production of liquid crystal panel - Google Patents

Abstract

PURPOSE:To obtain the liquid crystal panel which exhibits uniform orientation by subjecting the oriented films of substrates to a rubbing treatment, then to a heat treatment. CONSTITUTION:After a pair of the substrate oriented films 3, 6 having electrodes 2, 7 are formed, the oriented films 3, 6 of the substrates 1, 8 are subjected to the rubbing treatment then to the heat treatment. A liquid crystal 8 is sealed between the substrates 1 and 8. Namely, the liquid crystal molecules are unified in one direction by subjecting the oriented films to the rubbing treatment then to the heat treatment. The order parameters of the molecular arrangement are eventually increased. The liquid crystal panel which exhibits the uniform orientation over the entire part of the panel and has a high contrast is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a liquid crystal panel used in liquid crystal display devices, optical shutters, and the like.

BACKGROUND ART When manufacturing a liquid crystal panel, it is necessary to impart uniaxiality in order to align liquid crystal molecules in one direction, and for this purpose it is necessary to perform alignment treatment on a glass substrate. As orientation methods, rubbing methods, oblique evaporation methods, magnetic field application methods, electric field application methods, and the like have been devised, but the rubbing method is the most superior in terms of mass production and practicality.

FIG. 3 shows a method for manufacturing a liquid crystal panel using the conventional rubbing method.

That is, after forming transparent electrodes on two glass substrates, an alignment film is provided, and a rubbing process is performed. Spacers are scattered on one glass substrate, a seal is printed on the periphery of the other glass substrate, and these substrates are bonded together facing each other. After that, liquid crystal is injected between the substrates to form a liquid crystal panel.

Problems to be Solved by the Invention However, in the conventional method of bonding and injecting liquid crystal immediately after applying a rubbing process, the substrate surface is unstable and the molecular directions of the liquid crystal are not aligned in one direction, resulting in alignment defects. becomes more likely to occur. In particular, when a protein such as gelatin is used as the alignment film, the influence becomes noticeable, making it impossible to obtain a liquid crystal panel with high contrast.

The present invention aims to solve such conventional problems and to obtain a liquid crystal panel exhibiting uniform alignment.

Means for Solving the Problems To achieve the above object, the present invention involves forming a pair of substrate alignment films having electrodes, then subjecting the alignment film of at least one substrate to a rubbing treatment, and then subjecting the alignment film to a heat treatment. conduct,
A liquid crystal is sealed between the substrates.

According to the present invention, the liquid crystal molecules are aligned in one direction by performing the heat treatment after the rubbing treatment, and the order parameter of the molecular arrangement is increased, so that the liquid crystal panel exhibits uniform alignment over the entire panel surface. can be obtained.

EXAMPLE Hereinafter, a liquid crystal panel according to an example of the present invention will be described with reference to the drawings. The liquid crystal panel shown in FIG. 2 is manufactured by the manufacturing process shown in FIG.

That is, a transparent electrode 2.7 made of a transparent conductive film (ITO film) is formed on two transparent glass substrates Fi, 1.8.

After cleaning this glass substrate 1.8, an alignment film 3 is placed on it.
．． As 6, apply gelatin with a spinner and apply 100
'C After performing heat treatment for 1 hour to evaporate water, a rubbing treatment is performed using a rubbing cloth made of rayon. Each of these substrates was heated to 100'C1150°C120
Heat treatment is performed at 0°C and 1250°C for 1 hour. After that, SiO□ with a diameter of 6 μm is sprinkled as a spacer 9 on the portion of one glass substrate 1 where the alignment film 3 is provided, and UV sealing resin 4 is applied to the peripheral edge of the surface of the other glass substrate 8 where the alignment film 6 is provided. Both glass substrates 1.8 are coated with an alignment film 3.
．． They are pasted together so that the six sides face each other, and the UV sealing resin 4 is cured by UV irradiation. Thereafter, vacuum degassing is performed, and after injecting the liquid crystal 5 between the two glass substrates 1.8, the injection port is sealed. As a comparative example of this example, a liquid crystal panel was also manufactured by a method in which the materials were bonded and injected immediately after the rubbing treatment without heat treatment.

Table 1 shows the results of measuring the contrast of five types of liquid crystal panels manufactured in this manner.

As is clear from Table 1, it is possible to obtain a liquid crystal panel with high contrast and uniform alignment by performing heat treatment after rubbing. This is thought to be because heat treatment after rubbing aligns the liquid crystal molecules in the rubbing direction, increasing the order parameter of the molecular arrangement. Also, the heat treatment temperature is 200°
C or higher is preferable, but the orientation can be improved by heat treatment even at a temperature lower than 200°C.

In the above embodiments, at least one of the substrates needs to be transparent, and although gelatin was used as an example of the alignment film, similar effects can be obtained with other materials.

For example, it has been found that liquid crystal panels with high contrast can be obtained using polyimide, polyimide alcohol, nylon, and the protein albumin.

Effects of the Invention As is clear from the above explanation, according to the present invention, a rubbing treatment is performed after forming an alignment film, and liquid crystal is sealed between two heat-treated substrates, so that liquid crystal molecules are aligned in the rubbing direction. Since the order parameter of the molecular arrangement increases, a uniform liquid crystal panel with high contrast can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing a method for manufacturing a liquid crystal panel according to an embodiment of the present invention, FIG. 2 is a sectional view showing the structure of the same panel, and FIG. 3 is a process diagram showing a conventional method for manufacturing a liquid crystal panel. be.

Claims (2)

[Claims] (1) After forming an alignment film on a pair of substrates with electrodes,
Applying rubbing treatment to the alignment film of at least one substrate,
1. A method of manufacturing a liquid crystal panel, comprising: thereafter performing heat treatment to seal liquid crystal between the substrates. (2) The method for manufacturing a liquid crystal panel according to claim 1, wherein the alignment film is made of protein.