JPS61219026A - Formation of liquid crystal orienting film - Google Patents

Abstract

PURPOSE:To form easily a liquid crystal orienting film of a large area which is subjected uniformly to an orientation treatment by exposing the surface of a heat resistant synthetic resin film having an electrical insulating characteristic to glow discharge. CONSTITUTION:An electrode substrate 6 laminated with a polyimide film as the heat resistant synthetic resin film 5 having the electrical insulating characteristic on the electrode side surface by a method for vapor-depositing the raw material monomer of polyimide in a vacuum or the like is supported by a supporting member 7 between electrodes 4 and 4 approximately horizontally, i.e. in a manner as to be made approximately horizontal with the electric field direction. The inside of a treatment chamber is then evacuated to a vacuum and thereafter gaseous argon is introduced into the chamber 1 through a gas introducing pipe 3 so that the inside of the chamber is maintained under 0.01 Torr. The glow discharge is generated by impressing a DC voltage between the electrodes 4 and 4 and the surface of the film 5 is exposed to the positive column region thereof. The liquid crystal orienting film of the extremely uniform and large area which is entirely free from exfoliation and flawing is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for forming a liquid crystal alignment film laminated on an electrode substrate of a liquid crystal display device.

(Prior Art) Conventionally, as a method for forming this type of liquid crystal alignment film, a method is known in which the surface of an electrically insulating heat-resistant synthetic resin coating such as polyimide is subjected to a rubbing treatment. If the coating has peeled off, or if there is dust, etc. adhering to the surface of the synthetic resin coating or the cloth used to rub it, the surface of the coating may be scratched. Since it is difficult to perform a uniform rubbing treatment, there is a disadvantage that a large-area liquid crystal alignment film cannot be formed.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional inconveniences, and allows uniform alignment treatment to be performed without damaging the surface of the synthetic resin coating after it is peeled off from the electrode substrate. It is an object of the present invention to provide a method for forming a liquid crystal alignment film that can easily form a nine-faced liquid crystal alignment film.

(Means for Solving the Problems) In order to achieve the above object, the present invention consists of exposing the surface of an electrically insulating heat-resistant synthetic resin coating to a glow discharge.

The reason why the synthetic resin coating exhibits liquid crystal orientation by exposing the surface of the synthetic resin coating to a glow discharge is that ions, electrons, etc. generated during the glow discharge cause the synthetic resin coating to be exposed to an electric field. This is thought to be due to the fact that the light is incident on the surface at an angle close to horizontal to the electric field direction, thereby producing the same effect as rubbing treatment. Therefore, the synthetic resin coating that undergoes glow discharge treatment has its surface approximately horizontal to the direction of the electric field, or It is preferable to maintain the angle at an angle of up to 100 degrees. Furthermore, it is preferable that the synthetic resin coating is treated in the glow discharge, particularly in the anode column region.

(Examples) Examples of the present invention will be described below with reference to the accompanying drawings.

The drawing shows an example of an apparatus for carrying out the method of the present invention, and 1 indicates a processing chamber, and the processing chamber 1 is connected to an external vacuum pump or other evacuation system 2 to maintain an internal vacuum level of t-.
The processing chamber 1 is designed so that desired gases such as argon, nitrogen, nitrogen, hydrogen, helium, air, etc. can be introduced from the gas introduction pipe 3 communicating with the processing chamber 1. Inside, electrodes 4.4 for glue discharge are stacked parallel to each other, and between these electrodes 4.4,
Electrically insulating heat-resistant synthetic resin coating 5'f on the electrode side surface!
A support member 7 is provided to support the electrode substrate 6 having one FII layer.

In the figure, reference numeral 8 indicates a power supply for the electrode 4.4, and reference numeral 9 indicates a flow rate adjustment valve of the gas introduction pipe 3.

Here, an example of manufacturing a liquid crystal alignment film using the apparatus will be described.

First, a polyimide coating is laminated as an electrically insulating heat-resistant synthetic resin coating@5 on the electrode side surface by, for example, vapor-depositing a raw material monomer of polyimide in a vacuum.
Horizontal 303Xl bacteria electrode substrate 6t - its synthetic resin coating 5
It is supported by the support member 7 so that the surface is approximately horizontal between the electrodes 4 and 4, that is, approximately horizontal to the direction of the electric field.

Next, the inside of the processing chamber 1 is 1 xl 0 through the vacuum evacuation thread 2t.
After setting the pressure to about 1 to 1×10 −' Torr, argon gas is introduced through the gas introduction pipe 5 so that the pressure inside the processing chamber 1 becomes 0.01 L'orr. The gas pressure of the argon gas is adjusted so that the positive column area of the glow discharge is generated in the supported portion of the front distribution plate 6.

Thereafter, a DC voltage of -2 KV is applied to the electrode 4.4 to generate a glow discharge, and the surface of the synthetic resin coating 50 is exposed to the positive column region for 5 minutes.

In this way, a very uniform, large-area liquid crystal alignment film with no peeling or scratches can be obtained.90 Even if nitrogen, chlorine, hydrogen, helium, air, etc. are used instead of argon as the gas, the same results as in the previous example can be obtained. 9. An excellent liquid crystal alignment film can be obtained.

Furthermore, the liquid crystal alignment film could be formed in any region other than the dark part of the glow discharge, not only in the positive column region.

(Effects of the Invention) According to the present invention, since the surface of the electrically insulating heat-resistant synthetic resin coating is exposed during glow discharge, there is no peeling from the electrode substrate, and there is no scratch on the coating surface. It has the effect of easily forming an extremely uniform and large-area liquid crystal alignment film.

[Brief explanation of the drawing]

The drawing is a partially cut-away front view of an example of an apparatus for carrying out the method for forming a liquid crystal alignment film of the present invention. 1...Processing chamber 2...Evacuation system 3...Gas introduction pipe 4.4...Electrode 5...Electrical insulation Patent applicant for heat-resistant synthetic resin coating: 2 people other than Japan Vacuum Technology Co., Ltd.

Claims (1)

[Claims] A method for forming a liquid crystal alignment film comprising exposing the surface of an electrically insulating heat-resistant synthetic resin film to glow discharge.