JPH01200330A - Manufacture of liquid crystal display element - Google Patents

Abstract

PURPOSE:To uniform the curing of an orienting film and to shorten the curing time by forming the orienting film on a substrate and then curing the film under reduced pressure. CONSTITUTION:Substrates to which orienting film liquid is transferred are put in a carrier 20 one over another and the carrier 20 is carried in a pressure- tight container 22 by a conveyor belt 21. Then, the pressure in the pressure-tight container 22 is reduced, held as it is for 15min, and then put back to the atmo sphere. Then, a lamp 25 is used to heat the substrates at temperature below 100 deg.C, i.e. 80 deg.C for 30min, thereby curing the orienting film liquid. Consequently, uniform orienting films are obtained and the need to perform a heat treatment at 200-300 deg.C for about 3hr is eliminated; and no substrate deforms and the forming process time can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Industrial Application Field) The present invention relates to a method for manufacturing a liquid crystal display element, and particularly to a method for forming an alignment film for aligning liquid crystal.

(Prior Art) Generally, in a liquid crystal display element, an electrode pattern is formed on a glass substrate, and then an alignment film is formed and an alignment treatment is performed, and two glass substrates thus obtained are bonded to each other with an alignment film. The structure is such that the forming surfaces face each other and the liquid crystal is sandwiched between them.

Conventionally, when curing an alignment film, after transferring the alignment film onto a glass substrate on which an electrode pattern is formed, the glass substrate is fired at a firing temperature of 220'C for 3 hours, for example. -The alignment film was being cured.

(Problems to be Solved by the Invention) However, in such a method, air bubbles may be included during alignment film transfer, the glass substrate may be deformed due to the firing temperature because the glass substrate is thin, or the glass substrate may be broken. It is rarely the cause of Furthermore, the temperature and time required to cure the alignment film are long, resulting in a loss of manufacturing process time and an increase in manufacturing costs.

This invention was made in view of these circumstances.

[Structure of the Invention] (Means for Solving the Problems) The present invention is a method for manufacturing a liquid crystal display element in which liquid crystal is sealed between a plurality of substrates on which electrodes and alignment films are sequentially formed. The method of curing is reduced pressure.

(Function) - This invention cures the alignment film [Since high heating temperatures are not required, air bubbles generated during transfer of the alignment film can be removed, the alignment film is uniformly cured, and the display quality is significantly improved. At the same time, the curing time of the alignment film can be shortened and manufacturing costs can be reduced. Furthermore, the alignment film can be cured without causing deformation or cracking of the glass substrate due to firing, and the yield is improved.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an example of a liquid crystal display element obtained by the present invention, and FIG. 2 is a schematic diagram showing an apparatus for curing an alignment film used in the present invention. In FIG. 1, on the main surfaces of a plurality of substrates (1) and (2) made of, for example, glass, there are, for example, IT
Electron 4ff made of O (indium tin oxide)
i(3).

(4) is formed. Next, the same board (1),
On the main surface of (2) is an electrode (3).

(4) and an alignment film (5) to cover each of them.

(6) is formed. Here, the alignment film (5).

The method for forming (6) will be described in detail. As the alignment film liquid, for example, H-hymal type polyimide (HL-11 manufactured by Hitachi Chemical Co., Ltd.) with a viscosity of 70 Cp and a solid content concentration of 10% is used.
00), first apply this alignment film liquid to the substrates (1), (
2> by, for example, a spin coating method.

Next, place the substrates (1) and (2) on the carrier shown in Figure 2 (
20) and transfer it to the carrier (2) using the conveyor belt (21).
0) into a pressure-resistant container (22). Then, a pressure-resistant container (
22) By the function of the exhaust port (23), the inside is 0°01To
After reducing the pressure to rr and maintaining it for 15 minutes, open the air intake port (
24) returns it to atmospheric pressure. Next, the lamp (
25), the transferred alignment film liquid is cured by heating the substrates (1) and (2) at a temperature of 100° C. or lower, for example, 80° C., for one hour or less, for example, 30 minutes. After this,
The conveyor belt (21) transports the carrier (
20) Take out. In this way, - of the substrates (1) and (2>)
Alignment films (5) and (6) can be formed on the main surface.

Then, a sealing agent (7) made of, for example, thermosetting epoxy resin is applied to the permanent surface of one of the substrates (1) and (2>) in the shape of a frame with a portion that will become the liquid crystal injection port. print,
Spacers (8) made of, for example, glass fiber are sprinkled on the other side. Next, the board (1),
The liquid crystal (9) is sealed between the substrates (1) and (2>) by injecting the liquid crystal (9) into the wheat (combined so that the two sides face each other) through the liquid crystal injection port. let

After sealing the liquid crystal injection port, the substrate (1) is removed.

(2) On the other main surface side, there is a polarizing plate (10) and a polarizing plate (
11) and a reflective plate (12), a desired liquid crystal display element can be obtained.

In this example, an alignment film (5) is formed.

Since (6) is partially cured under reduced pressure, a very uniform product can be obtained, and the number of spots, which are thought to be caused by polyimide bubbles, for example, is extremely small to 1/3 to 1/4 compared to conventional methods. Ta. And special heating i.e. conventional 2
Since heating for about 3 hours at a temperature of 00 to 300 degrees Celsius is not required, the substrates (1) and (2> do not deform due to heating, and the damage rate is reduced to 1/2 to 1/3 compared to conventional methods. In addition, an effect was obtained in that the resistance of the electrodes (3">, (4) does not increase due to heating. Furthermore, the manufacturing process time can be shortened compared to the conventional alignment film forming method for liquid crystal display elements. , second
In order to cure the alignment films (5) and (6) using a vacuum device as shown in the figure, the alignment film (5)! (6) Air bubbles and organic solvents during transfer can be removed.

The materials used for the alignment films (5>, (6)) preferably contain hardened polyimide particles in a solvent; other materials include JIB manufactured by Japan Synthetic Rubber Co., Ltd. In addition, even when color filters are attached to the substrates (1) and (2>), or when films are used as the substrates (1) and (2>, the manufacturing process can be similarly performed at low temperatures by using the method of this invention. For example, decolorization or discoloration of the color filters will not occur.Furthermore, essentially, curing of the alignment films (5) and (6> only requires a means of reduced pressure; As mentioned in the example, by incorporating a heating step, the curing time can be further shortened.

[Effects of the Invention] In this invention, after the alignment film is transferred to the substrate on which the electrode pattern is formed, the pressure is reduced and the alignment film is cured. Since the alignment film can be cured without deforming or cracking the substrate, a highly uniform liquid crystal display element can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a liquid crystal display element obtained according to an embodiment of the present invention, and FIG. 2 is a schematic view showing an example of an apparatus used for curing an alignment film in the present invention. (1), (2>... Substrate (3), (4>... Electrode (5), (6)... Alignment film (9)... ...LCD agent and patent attorney Nori Chika and Kikuo Takehana.

Claims (1)

[Claims] In a method for manufacturing a liquid crystal display element in which liquid crystal is sealed between a plurality of substrates on which electrodes and alignment films are sequentially formed, the alignment film is formed on the substrates and then cured under reduced pressure at least once. A method for manufacturing a liquid crystal display element, comprising: