JP2554875B2 - Liquid crystal device manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a liquid crystal device. More specifically, it relates to a rubbing method for aligning liquid crystals.

[Conventional technology]

As a conventional liquid crystal display alignment method, a polyimide-based polymer resin is applied on a substrate and then rubbed in a certain direction with a cloth or the like (JP-A-55-143525), or a rubbing cloth is wound. The method of rubbing by rotating the attached drum was performed.

[Problems to be solved by the invention]

However, the method of rubbing by rotating the drum around which the rubbing cloth is wound (hereinafter referred to as “rotational rubbing”) is advantageous for obtaining a uniform orientation, but on the other hand, it is very difficult to set the conditions, The distance between the surface of the substrate and the rotating body around which the rubbing cloth is wound varies, and scratches (hereinafter referred to as line hold) occur on the alignment film. This flaw is a drawback that the display quality of the display device is deteriorated. That is, when it becomes a panel, the scratched portion is exposed so that it can be visually confirmed. Further, the control of the interval is not easy and has been a problem in practical use.

Therefore, the present invention solves such a problem, and an object thereof is to provide a liquid crystal display device manufacturing method suitable for mass production, which makes it possible to obtain a uniform alignment with no line hold and facilitates condition setting. Where it is.

[Means for solving problems]

A method for manufacturing a liquid crystal device according to the present invention is a method for manufacturing a liquid crystal device in which a liquid crystal is sandwiched between a pair of substrates, and an alignment film is formed on a surface of the substrate on the side in contact with the liquid crystal, The value of the rubbing density represented by A−V) / V is 15 to
The alignment film is rubbed under the condition of 1000. Where r (cm) is the diameter of the drum around which the rubbing cloth is wound, A (rpm) is the rotation speed of the drum, and V (cm / mi)
n) represents the moving speed of the substrate.

The rubbing density is preferably 15 to 1000. If the rubbing density is less than 15, rubbing becomes insufficient, resulting in not only uneven alignment but also line hold. On the other hand, if it exceeds 1000, the rubbing density is too high, so that the alignment film is scraped off, the surface irregularities are severe and the alignment unevenness occurs, and the line hold easily occurs.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to one illustrated embodiment.

FIG. 1 is a schematic view of a rubbing apparatus used in the present invention, where 1 is a metallic rotating body supported by a supporting body (not shown), and 2 is a rubbing cloth attached around the rotating body 1. The rubbing cloth used was a general cloth such as nylon, vinylon, polyester, acryl, rayon and the like.

Example 1 The rotational speed A of the rotating body 1 is 500 (rpm), and the diameter r of the rotating body 1 is
10 (cm), the moving speed V of the substrate 3 and the support 4 is 157
(Cm / min) was set. Rubbing density at this time (πr ×
AV) / V is about 100.

First, a polyimide resin solution is applied on a substrate on which a transparent electrode having a predetermined pattern is formed of tin oxide or indium oxide by a spinner or the like, and then baked to form an alignment film of 100 to 300 Å made of polyimide. The substrate on which the transparent electrode and the alignment film were thus formed was rubbed under the above conditions. As the rubbing cloth 2, flocked type polyester was used.

The upper and lower substrates that were rubbed as described above were bonded with a sealant or the like at regular intervals, and then liquid crystal was sealed to form a liquid crystal display device. As a result, scratches were not visible on the display surface, and a uniform display surface was obtained.
Therefore, it can be said that the line hold does not occur.

Further, even if the distance between the rubbing cloth 2 and the substrate 3 fluctuates to some extent, a line hold does not occur and a stable orientation can be obtained.

Example 2 A liquid crystal display device was constructed using a substrate treated in the same manner as in Example 1 except that the rubbing density was set to about 20 and an epoxy resin was used as an aligning agent, and the same results as in Example 1 were obtained. Was given.

Example 3 A liquid crystal display device was constructed using a substrate treated in the same manner as in Example 1 except that the rubbing density was about 500.
The same result as in Example 1 was obtained.

Example 4 A liquid crystal display device was constructed using a substrate treated in the same manner as in Example 1 except that the rubbing density was about 1000.
The same result as in Example 1 was obtained.

Example 5 A liquid crystal display device was constructed using a rubbing density of about 100 and a rubbing-processed substrate using rayon, and the same results as in Example 1 were obtained.

Comparative Example 1 The rubbing density is set to about 10 (as a setting method,
(1) Increase the substrate moving speed. (2) Reducing the diameter of the rotating body (3) Reducing the rotating speed of the rotating body. Then, a liquid crystal display device was manufactured using the substrate treated in the same manner as in Example 1.

When this liquid crystal display device was observed, linear streaks (line hold) that could be visually confirmed appeared on the display surface, impairing the display appearance. In addition, since the orientation is incomplete, the display surface has unevenness, which cannot be used as a display device.

Comparative Example 2 A liquid crystal display device was constructed using the substrate treated in the same manner as in Example 1 with the rubbing density set to about 1200. When this liquid crystal display device was observed, similar to Comparative Example 1, linear streaks (line hold) visible to the naked eye were conspicuous on the display surface, and the unevenness of the surface of the alignment film was severe, resulting in uneven alignment. As a result, display unevenness has occurred, which is an obstacle for the display device.

The number of revolutions A, the diameter r, and the moving speed V of the substrate and the support are not limited to those in this embodiment, and other conditions may be used. What is important is to set the rubbing density to 15 to 1000. That is, the effect of the present invention can be obtained.

Furthermore, the present inventors have found that the preferred range of rubbing density is
It was found to be in the range of 15 to 1000. That is, if it is less than 15, rubbing becomes insufficient, resulting in not only uneven alignment but also line hold. If it exceeds 1000, the rubbing density is too high and the alignment film is scraped off, resulting in severe surface irregularities and uneven alignment and line hold.

Further, the alignment film used in the present invention is not limited to this embodiment, and is also effective for the following well-known aligning agents.

Organic polymers such as polyvinyl alcohol, polyamide imide, polyamide, polyether sulfone, polycarbonate, polyester, urethane resin, phenol resin, silicon resin.

The film thickness of the alignment film has the same effect in a widely used range (for example, 100 to 1000Å) and is not limited to this example.

〔The invention's effect〕

As described above, according to the method for manufacturing a liquid crystal device of the present invention, the alignment film is rubbed under the condition that the value of the rubbing density represented by the formula (πr × A−V) / V is 15 to 1000. As a result, a uniform alignment film having no line hold can be obtained. Further, the condition can be easily set based on the formula of the rubbing density, which is suitable for mass production.

[Brief description of drawings]

 FIG. 1 is a schematic view of a rubbing device used in the present invention. DESCRIPTION OF SYMBOLS 1 ... Rotating body 2 ... Rubbing cloth 3 ... Glass substrate 4 ... Substrate support base 5 ... Alignment film

Claims (1)

(57) [Claims] 1. A method of manufacturing a liquid crystal device, comprising: a liquid crystal sandwiched between a pair of substrates; and an alignment film formed on a surface of the substrate in contact with the liquid crystal. A method for manufacturing a liquid crystal device, comprising: rubbing the alignment film under the condition that the value is 15 to 1000. (Πr × A−V) / V where r (cm) is the diameter of the drum around which the rubbing cloth is wound, A (rpm) is the rotation speed of the drum, and V (cm / min) is the moving speed of the substrate.