JPH0463323A - Treatment of orienting liquid crystal - Google Patents

Abstract

PURPOSE:To provide the dustfree treatment method of high productivity by exposing the surface of a liquid crystal oriented film to an ion shower by which the liquid crystal oriented film is subjected to a uniform orientation treatment without peeling the liquid crystal oriented film. CONSTITUTION:The inside of a vacuum chamber 1 is evacuated to 1X10<-6> Torr by a vacuum pump 3 and thereafter, gaseous argon is introduced into the vacuum chamber 1 from a gas introducing port 4 and is set at a desired vacuum degree in the case of using polyimide as the liquid crystal oriented film and argon as gas species. Argon plasma is thereafter generated in a glow discharge generating chamber 2 by using a microwave power source which generates 2.45GHz microwaves 5. Active particles, such as ions, electrons, excited atoms, excited molecules, and light are formed in the generated argon plasma and ions are drawn out by an ion drawing out electrode 7. The substrate 8 on which the liquid crystal oriented film of the polyimide is previously formed is exposed to these ions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a liquid crystal alignment treatment method for a liquid crystal alignment film laminated on an electrode substrate of a liquid crystal display element.

[Prior Art 1] Conventionally, as a liquid crystal alignment treatment method for this type of liquid crystal alignment film, a rubbing treatment method is known in which, for example, the surface of polyimide is rubbed with a cloth or the like. Moreover, as another method, there is an oblique vapor deposition method in which SiOx itself, which is a liquid crystal alignment film material, is vapor-deposited obliquely onto a substrate.

[Problem to be Solved by the Invention 1] However, in the above-mentioned alignment treatment method for a liquid crystal alignment film using the rubbing process, the alignment film such as polyimide may peel off, and fibrous particles generated from the cloth used in this method may occur. This has the disadvantage that display defects are likely to occur due to dust.

On the other hand, although the method using oblique evaporation of SiOx does not have the above disadvantages, it has the problem of low productivity.

The present invention is intended to solve these problems, and its purpose is to provide a liquid crystal alignment treatment method that is dust-free and highly productive, in which liquid crystal alignment treatment is performed uniformly without peeling of the liquid crystal alignment film. It is in a place where we provide.

[Means to solve the problem] The liquid crystal alignment treatment method of the present invention is characterized by the following.

(1) Consists of exposing the surface of the liquid crystal alignment film to an ion shower.

(2) The liquid crystal alignment film is made of polyimide, polyvinyl alcohol, polyethylene oxide, polyacrylonitrile, SiOx, TaxOs, IT.

consisting of a film containing at least one of the following.

(3) The gas species forming the ion shower contains at least one of hydrogen, helium, oxygen, nitrogen, argon, and water vapor.

〔Example] The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an example of an apparatus for carrying out the method of the present invention, in which 1 is a vacuum chamber, and a glow discharge generation chamber 2 is provided within the chamber. 3 is a vacuum pump, 4 is a gas inlet port, and a mass flow controller is used for pressure control, but the exhaust speed may be controlled on the vacuum pump 3 side. 5 is a microwave, which generates a so-called ECR discharge using resonance with a magnetic field generated by an electromagnet 6.

The method of generating this glow discharge is not limited to ECR power generation.
DC discharge and RF discharge are also possible. Reference numeral 7 denotes an ion extraction electrode, which is equipped with a power source that applies a direct current negative potential. Reference numeral 8 denotes a substrate holder 9 equipped with an angle changing mechanism that can change the angle at which the substrate to be processed is exposed to the ion shower.
I support it.

An example of a liquid crystal alignment treatment method using this apparatus will be described below in the case where polyimide is used as the liquid crystal alignment film and argon is used as the gas species.

The inside of the vacuum chamber 1 is heated with lXl0-'Tor by the vacuum pump 3.
After exhausting the vacuum chamber 1, argon gas is introduced into the vacuum chamber 1 through the gas inlet 4 to set the desired degree of vacuum. Thereafter, although not shown in the figure, argon plasma is generated in the glow discharge generation chamber 2 using a microwave power source that generates microwaves 5 of 245 GHz. Active particles such as ions, electrons, excited atoms, excited molecules, and light are generated in the generated argon plasma, and the ions are extracted by an ion extraction electrode 7 and exposed to a substrate 8 on which a polyimide liquid crystal alignment film has been previously formed.

The manufacturing and forming conditions are wide-ranging, but to give one example, the processing gas pressure is naturally in the dischargeable range, but the higher the gas pressure, the more ions will be extracted by the ion extraction electrode 7, and the processing time will be shorter. Further, even if the negative potential applied to the ion extraction electrode 7 is made thicker, the processing time will be shortened.

However, in this case, if the negative potential is made too large, the surface of the liquid crystal alignment film is damaged by physical impact, which is similar to that caused by strong rubbing during conventional rubbing treatment. After all, the negative potential applied to the ion extraction electrode 7 is comparable to the pressure applied by a roller to the liquid crystal alignment film during conventional rubbing processing, and therefore, the liquid crystal alignment force can be adjusted by the potential of the ion extraction electrode 7. . Further, the most efficient angle of the ion shower with respect to the normal direction of the substrate 8 is about 40° to 80°, and the larger the angle, the smaller the pretilt angle of the liquid crystal molecules. That is, the pretilt angle of the liquid crystal molecules can be adjusted by adjusting the angle of the substrate 8 with respect to the ion shower.

By the above method, the argon gas pressure is set to 1 O-2Torr,
When alignment treatment was performed at an ion extraction potential of -100 cm, an ion shower angle of 70 degrees with respect to the normal direction of the substrate, and a processing time of 1 minute, a highly uniform alignment was obtained, and the liquid crystal as measured by magnetic field potential method was The pretilt angle of the molecule was 05°.

Polyvinyl alcohol, polyethylene oxide, polyacrylonitrile, SiOa, Ta for liquid crystal alignment film
When using gOs and ITO, uniform orientation can be obtained similarly to polyimide, but when using 5io2. Taa Os, I
In the case of TO, in order to obtain the same orientation as other organic films, the negative potential applied to the ion extraction electrode 7 is increased compared to the alignment treatment conditions for organic films, but it is necessary to lengthen the treatment time. .

Regarding the gas type, the alignment treatment was effective with hydrogen, helium, oxygen, nitrogen, and water vapor, but when using a gas type containing oxygen, the surface of the ion extraction electrode 7 may deteriorate if the device is continued to be used. The electrodes need to be cleaned or replaced regularly because they become oxidized and the extraction effect weakens.

[Effects of the Invention] As described above, according to the present invention, by exposing the surface of the liquid crystal alignment film to an ion shower, the liquid crystal alignment film can be uniformly subjected to a liquid crystal alignment treatment without peeling and is dust-free. This has the effect that liquid crystal alignment treatment can be performed with high productivity.

Furthermore, the liquid crystal alignment force can be adjusted by adjusting the ion extraction potential.

Furthermore, it has the great effect that the pretilt angle of the liquid crystal molecules can be adjusted by adjusting the angle of the ion shower with respect to the substrate.

[Brief explanation of the drawing]

Figure 1 shows the equipment for carrying out the liquid crystal alignment treatment method of the present invention!
Schematic diagram showing an example. 1 ・ ・ 2 ・ 3 ・ ・ 4 ・ ・ 5 ・ ・ 6 ・ ・ 7 ・ ・ 8 ・ ・ 9 ・ ・ Vacuum chamber glow 111 Electron generation chamber Vacuum pump Gas inlet Microwave magnet Ion extraction electrode Substrate to be processed Substrate holder and above Applicant Seiko Epson Corporation

Claims (3)

[Claims] (1) A liquid crystal alignment treatment method comprising exposing the surface of a liquid crystal alignment film to an ion shower. (2) The liquid crystal alignment method according to claim 1, wherein the liquid crystal alignment film is a film containing at least one of polyimide, polyvinyl alcohol, polyethylene oxide, polyacrylonitrile, SiO_2, Ta_2O_5, and ITO. (3) The liquid crystal alignment method according to claim 1, wherein the gas species forming the ion shower contains at least one of hydrogen, helium, oxygen, nitrogen, argon, and water vapor.