JPH05142508A - Production of liquid crystal display element - Google Patents

Abstract

PURPOSE:To prevent the generation of bubbles in a liquid crystal cell and to shorten the time for injection by aligning the direction of rubbing nearly to a direction distant from a liquid crystal injection port, i.e., the injection direction of the liquid crystal. CONSTITUTION:Transparent electrodes respectively consisting of ITO and oriented films consisting of polyimide resins are formed on substrates 1, 2 and thereafter, the oriented films are rubbed from the liquid crystal injection port 10 side. The rubbing is executed by setting the rubbing direction R with respect to the oriented film on the substrate 1 side at, for example, right upgrade 30 deg. angle and setting the rubbing direction R with respect to the oriented film on the substrate 2 side at right downgrade 30 deg. angle when the liquid crystal injection port 10 is positioned on the left side at this time. The twist angle of the liquid crystal is set at 240 deg.. The rubbing directions R of the substrates 1, 2 are respectively set at 30 deg. and these angles R are respectively settable from 0 up to 45 deg.. In short, a satisfactory result is obtd. if the rubbing direction R is so set as to be in nearly the same direction as the liquid crystal injection direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a liquid crystal display device (hereinafter referred to as L
And a rubbing treatment method.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
First, transparent electrodes (3) and (4) are formed on one surface of the substrates (1) and (2), respectively, and an alignment film (5) is formed on the transparent electrodes (3) and (4). , (6) are formed.
Then, an alignment treatment is performed by rubbing the alignment films (5) and (6) in a certain direction with a cloth or the like, and then a seal material is applied to one of the substrates (1) and (2). , The substrates (1) and (2) are attached. The liquid crystal is injected into the gap of the liquid crystal cell thus manufactured, and the substrate (1),
LCDs are manufactured by attaching polarizing plates (7) and (8) to the outer surfaces of (2), respectively.

[0003]

By the way, when the rubbing direction R is set to the direction toward the liquid crystal injection port (10) as shown in FIG. 2, bubbles are generated in the liquid crystal cell when the liquid crystal is injected. However, there is a problem that it takes a long time to inject the liquid crystal. This phenomenon is because the twist angle of the liquid crystal is 1
It is remarkable in so-called STN-LCD of 80 ° or more. In particular, when bubbles are generated, there is a problem that if the liquid crystal is sealed in the presence of the bubbles, the bubbles will remain forever, resulting in display failure of the LCD. Therefore,
A method of solving the above-mentioned problem by providing a plurality of liquid crystal injection ports (10) and increasing the liquid crystal injection amount per time has been considered, but if the number of liquid crystal injection ports (10) increases, the gap between the liquid crystal cells will increase. Since the number of notches increases in the seal material that determines the above, it becomes difficult to obtain a predetermined gap, and at the same time, the moisture resistance deteriorates.

Therefore, an object of the present invention is to prevent bubbles from being generated in a liquid crystal cell and to shorten the liquid crystal injection time without deteriorating the performance and reliability of the LCD.

[0005]

The above-mentioned problems are solved by making the rubbing direction substantially coincide with the direction away from the liquid crystal injection port, that is, the liquid crystal injection direction.

[0006]

As shown in FIG. 4, the liquid crystal molecules (12) are aligned in the rubbing direction R on the alignment film (5) and the rubbing direction R
It is known to slightly incline. Liquid crystal inlet (1
When rubbing toward (0), as shown in FIG. 5, the inclination of the liquid crystal molecules (12) is opposite to the injection direction A of the liquid crystal, so that the liquid crystal is difficult to enter and at the same time bubbles are easily generated. On the other hand, in the present invention, as shown in FIG. 6, the inclination of the liquid crystal molecules (12) and the injection direction A of the liquid crystal are in the forward direction, so that the liquid crystal easily enters and bubbles are not generated.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing the rubbing direction, and FIG. 6 is a cross-sectional view of an essential part showing the liquid crystal injection direction and the rubbing direction. Since the basic sectional structure of the LCD obtained by the manufacturing method of the present invention is the same as the general LCD structure shown in FIG. 3, the following description will also refer to FIG. According to the present invention, after the transparent electrodes (3) and (4) made of ITO and the alignment films (5) and (6) made of polyimide resin are formed on the substrates (1) and (2), respectively, the alignment films are formed. (5), (6)
Then, rubbing is performed from the liquid crystal injection port (10) side. Figure 1
When the liquid crystal injection port (10) is located on the left side as shown in (4), the rubbing direction R with respect to the alignment film (5) on the substrate (1) side is an angle of 30 ° to the right and also on the substrate (2) side. The rubbing direction R with respect to the alignment film (6) is 30 ° to the right.
And the twist angle of the liquid crystal is set to 240 °.
Next, the substrates (1) and (2) are coated with epoxy resin or U.
After bonding with a seal material (9) made of a V (ultraviolet) curable resin and injecting liquid crystal through a liquid crystal injection port (10) by a vacuum injection method, a sealing material made of a UV curable resin (not shown) Is applied to the liquid crystal injection port (10) and cured to seal the liquid crystal (11). Finally, polarizing plates (7) and (8) having polarization axes set at a predetermined angle are attached to the outer surfaces of the substrates (1) and (2). In the LCD manufactured in this manner, the liquid crystal molecules (12) are inclined in the forward direction by about 5 to 7 ° with respect to the liquid crystal injection direction A. For a 640 × 200 dot LCD, the liquid crystal injection time was about 30 minutes, and no bubbles were generated. On the other hand, liquid crystal molecules (12)
However, in the LCD which opposes the liquid crystal injection direction A, the liquid crystal injection time was about 40 minutes, and many bubbles having a diameter of 0.1 to 0.2 mm were generated.

In the embodiment, the rubbing directions R of the substrates (1) and (2) are described as being 30 °, but the angles can be set to 0 to 45 °. In short, the rubbing direction R may be substantially the same as the liquid crystal injection direction A.

[0009]

As described above, according to the present invention, it is possible to prevent the generation of bubbles in the liquid crystal cell and shorten the liquid crystal injection time without deteriorating the performance and reliability of the LCD.

[Brief description of drawings]

FIG. 1 is a plan view showing a rubbing direction of an LCD according to an embodiment of the present invention.

FIG. 2 is a plan view showing a rubbing direction of an LCD according to a conventional example.

FIG. 3 is a sectional view of a general LCD.

FIG. 4 is a main-portion cross-sectional view showing the relationship between rubbing directions and liquid crystal molecules.

FIG. 5 is a cross-sectional view of a main part showing a relationship between a rubbing direction and a liquid crystal injection direction according to a conventional example.

FIG. 6 is a cross-sectional view of essential parts showing the relationship between the rubbing direction and the liquid crystal injection direction according to the present invention.

[Explanation of symbols]

 1, 2 substrate 3,4 transparent electrode 5,6 alignment film 9 seal material 10 liquid crystal injection port A liquid crystal injection direction R rubbing direction

Claims (1)

[Claims] 1. A transparent electrode on each of the inner surfaces of two substrates,
An alignment film is provided on the transparent electrode, and after rubbing the alignment film, the substrate is bonded with a seal material with a predetermined gap, and a liquid crystal is injected into the gap. A method for manufacturing a liquid crystal display device, wherein the direction of is substantially the same as the injection direction of the liquid crystal.