JPS63240522A - Production of liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain a liquid crystal display device suitable for mass production by rubbing an oriented film within a specific range of rubbing density thereby obtaining the orientation having no flaws, i.e., line holds, of the oriented film and facilitating setting of conditions. CONSTITUTION:The rubbing density (pirXA-v)/v when the number of revolutions of a rotating body is designated as Arpm, the diameter of the body as rcm and the moving speed of a beam material 3 and a supporting base 4 as vcm/min is set at 15-1,000. A polyimide resin soln. is coated by a spinner, etc., on the substrate 3, on which transparent electrodes of a prescribed pattern are formed by tin oxide or indium oxide, etc. The coating is then calcined after drying to form the oriented film t consisting of polyimide on the substrate. The substrate 3 is thereafter subjected to the rubbing treatment, in which polyes ter of flocking type is used as a rubbing cloth 2. The upper and lower substrates 3, 3 subjected to the rubbing treatment are combined and adhered by a sheeting agent, etc., at a specified spacing, following which a liquid crystal is sealed therebetween to constitute the liquid crystal display device. The uniform display having no defective orientations such as line holds is thereby attained and the liquid crystal display device having a high display grade is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rubbing method for orienting liquid crystal molecules in a certain direction.

[Conventional technology]

Conventional methods for aligning liquid crystal display devices include coating a polyimide polymer resin on a substrate and then rubbing it in a certain direction with a cloth (Japanese Patent No. 55-143525), or using a rubbing cloth. A method of rubbing by rotating a wrapped drum was used.

C Problems to be Solved by the Invention] However, the method of rubbing by rotating a drum wrapped with the rubbing cloth described above (hereinafter referred to as "rotary rubbing method") is not advantageous in obtaining uniform orientation. However, on the other hand, it is very difficult to set the conditions, especially when the rubbing cloth is wrapped around the surface of the substrate and the distance between the rotating body varies and the alignment film is scratched (
Scratches that cause line holds (hereinafter referred to as line holds) are a drawback that degrade the display quality of the display device.

That is.

When it comes to panels, the scratches are exposed enough to be visible. Furthermore, it is not easy to control the spacing, which poses a problem in practical use.

Therefore, the present invention solves these problems.
The purpose is to obtain a uniform alignment without line hold, as well as to easily set one condition, making it a liquid crystal display suitable for mass production! !
5! ml! It's about providing a way to send money.

[Means for solving problems]

A method of manufacturing a liquid crystal display fcffil: according to the present invention is a method of manufacturing a liquid crystal display device in which a liquid crystal is sandwiched between a pair of substrates on which all liquid crystal molecules are aligned in a fixed direction by rubbing an alignment film on the substrates. The orientation on one substrate is determined by the diameter tr (cat) of the drum wrapped with rubbing cloth, the rotation speed A (rpm), and the substrate movement speed tv (a
n/m”).

It is characterized by comprising a step of rubbing at a rubbing density expressed by (πrxmu-7)/v in the range of 15 to 1000.

The above-mentioned rubbing density is preferably 15 to 1000. If it is less than 15, the rubbing will be insufficient, resulting in uneven alignment as well as line hold. If it exceeds 1000, the rubbing density will be too high and the alignment will be distorted. The unevenness of the final surface is severe, causing alignment unevenness and line hold.

[Implementation row]

The present invention will now be described in detail using the following five figures.

FIG. 1 is a schematic diagram of a rubbing device used in the present invention,
Reference numeral 1 is a metal rotating body supported by a support (not shown), and 22 is a piece of cloth attached around the rotating body 1. As the rubbing cloth in step 2, a general cloth such as nylon, vinylon, polyester, acrylic, rayon, etc. was used.

Implementation row 1 The rotation speed A of the rotating body l was set to 500 (?'pm), the diameter r of the rotating body l was set to 10 (cIR), and the moving speed of the substrate 3 and the support base 4 was set to 157 (cys/min). .

Rubbing density at this time (πy X A-V) / V
is approximately 100.

First, a polyimide resin solution is coated on a substrate on which a transparent electrode of a predetermined pattern is formed using tin oxide or indium oxide, etc. with a tin oxide, a coating material, etc., and then baked to form an oriented 1[t-100 to 300 μm] made of polyimide. do. The substrate on which the transparent electrode and alignment film were formed was subjected to a rubbing treatment under the conditions described above. As the rubbing cloth 2, flocked polyester was used.

After the upper and lower substrates subjected to the rubbing process as described above were combined and adhered at a constant interval using a sealant or the like, liquid crystal was sealed to form a liquid crystal display device t. As a result, no scratches were visible on the display surface.

A uniform display surface was obtained. Therefore, it can be said that line hold does not occur.

Further, even if the distance between the rubbing cloth 2 and the substrate 3 varied somewhat, no line hold occurred and a stable orientation could be obtained.

Practical row 2 Actual tfI except that the rubbing density was set to about 100% and epoxy resin was used as the alignment agent! A liquid crystal display device was formed using a substrate treated in the same manner as AIPI11.

Results similar to those in implementation fFI11 were obtained.

Example 3 A liquid crystal display device was constructed using a substrate treated in the same manner as Example 1 except that the rubbing density was about 500, and the results of Example 1 and colleagues were 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 approximately 1000, and the same results as in Example No. 1 were obtained.

Implementation row 5: The rubbing density is approximately 100. When a liquid crystal display device was constructed using a substrate rubbed with rayon as a rubbing cloth, the same results as in Example 1 were obtained.

Comparison row 1 Set the rubbing density to approximately 1O (setting method is as follows:
(1) Increase the movement speed of the board. (2) Decreasing the diameter of the rotating body) There are several ways to reduce the rotation speed of the rotating body. ) A liquid crystal display device was manufactured using a substrate treated in the same manner as in Example 1.

When this liquid crystal display device was observed, it was found that the display surface had linear streaks (line holds) that were visible to the naked eye, detracting from the appearance of the screen display. Also, because the orientation is incomplete, unevenness can be seen on the display surface.

This made it impossible to use it as a display device.

Comparison Row 2 A liquid crystal display device was manufactured using a substrate treated in the same manner as in Example Row 1, with the rubbing density set at about 1200. An observation of this liquid crystal display device.

As with comparison column l, it can be confirmed with the naked eye on the display screen;! 3
In addition to conspicuous a-shaped streaks (line holds), the unevenness of the surface of the alignment film was severe, resulting in alignment unevenness, resulting in display unevenness, which was problematic as a display device.

In addition, the number of revolutions A, the diameter r, and the moving speed V of the support on the substrate
is not limited to this example, and other conditions may be used; one important thing is the rubbing density t-15 to 100.
By setting it to 0, the effects of the present invention can be obtained.

Furthermore, the present inventor has determined that the preferred range of rubbing density is 1
It was found that the number is in the range of 5 to 1000. In other words, if it is less than 15, there will be insufficient rubbing, resulting in not only uneven alignment but also line hold.
If it exceeds 1000't-, the rubbing density is too high and the alignment film is scraped, resulting in severe unevenness on the surface, resulting in alignment unevenness and line hold.

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

Organic polymer materials such as polyvinyl alcohol, polyamideimide, polyamide, polyether sulfon, polycarbonate, polyester, urethane resin, phenol resin, silicone resin, etc.

The film thickness of the above-mentioned alignment film has the same effect within a widely generally used range (for example, 100 to xoooX), and is not limited to this practical range.

〔Effect of the invention〕

According to the first invention, the rubbing process for orienting the liquid crystal molecules't in a certain direction can be performed at a rubbing density of 15 to 15.
A liquid crystal display device with high display quality can be provided if uniform display without alignment defects such as line hold can be realized by controlling the angle within the range of 1000.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a rubbing device used in the present invention. 1...Rotating body 2...Rubbing cloth 3...-Glass substrate 4. One board support stand 5＠・・・Orientation film that's all Applicant: Seiko Epson Corporation Agent: Patent attorney Rk): Mr. and 1 other person, Pai'~.

Claims (1)

[Claims] In a method for manufacturing a liquid crystal display device in which a liquid crystal is sandwiched between a pair of substrates in which liquid crystal molecules are aligned in a certain direction by rubbing an alignment film on the substrates, the alignment film on at least one substrate is provided. , the diameter of the drum wrapped with rubbing cloth is γ (cm), the rotation speed is A (rpm), and the moving speed of the substrate is V (cm/cm).
1. A method for manufacturing a liquid crystal display device, comprising the step of rubbing at a rubbing density expressed by (πγ×AV)/V in the range of 15 to 1000.