JPH0381730A - Manufacture of liquid crystal display panel - Google Patents

Abstract

PURPOSE:To clean the surfaces of oriented films without adversely affecting an orientation treatment by subjecting the surfaces of the oriented films on substrates to a rubbing treatment, then subjecting the surfaces of the oriented film to a scrubbing treatment in the same directions as the rubbing directions while making washing liquid flow. CONSTITUTION:The oriented film is formed on the substrates 1. Since the twisting angle is 90 deg., the rubbing direction of the common substrate is intersected orthogonally with that of the segment substrate facing this substrate. The rubbing directions intersect at 45 deg. with the side AB of the substrate 1. The directions face C from the vertex A of the common substrate and conversely face A from the direction C of the segment substrate in either case. After the surfaces of the oriented films are subjected to the rubbing treatment, the surfaces are subjected to the scrubbing treatment in the same direction as the rubbing directions while making the washing water flow by using a washing brush 3.

Description

[Detailed Description of the Invention] [Summary] The purpose of this invention is to prevent a decrease in yield due to adhesion of rubber ξ in the alignment treatment process in a method for manufacturing a liquid crystal display panel, particularly in the rubbing treatment and subsequent cleaning process. After performing a rubbing treatment on the surface of the alignment film formed on the substrate, the surface of the alignment film is
A configuration including a step of performing a scrubbing process in the same direction as the rubbing process direction while flowing a cleaning liquid, and a step of scrubbing the surface of the alignment film formed on the substrate in a predetermined direction while flowing the cleaning liquid, thereby removing the alignment film. The structure includes a step of simultaneously performing surface cleaning and orientation treatment.

[Industrial application field]

The present invention relates to a method for manufacturing a liquid crystal display panel, and particularly to a rubbing treatment and subsequent cleaning process.

Currently, the rubbing method, which is widely used as an alignment treatment method for liquid crystals, has problems such as the adhesion of rubber onto the substrate surface. The emergence of a method is strongly desired.

[Conventional technology]

Conventional alignment film rubbing and subsequent cleaning methods generally involve first aligning the alignment film surface in one direction using a rubbing roll made of fibers such as rayon or nylon, and then performing wet cleaning. It is.

The reason why we perform non-contact wet cleaning instead of using a contact cleaning method is that contact cleaning scrapes the surface of the alignment film, which disturbs the alignment direction specified in the rubbing process in the previous process. This is because you end up doing it.

Therefore, as this wet cleaning method, a non-contact cleaning method such as air bubbling cleaning or ultrasonic cleaning is used so as not to adversely affect the alignment treatment by rubbing treatment.

It is known that the above-mentioned non-contact type cleaning method is generally inferior to the contact type cleaning method in terms of removal rate of dust attached to the substrate.

[Problem to be solved by the invention]

Therefore, in the conventional manufacturing process, defects such as short circuits and gap thickness abnormalities occur due to dust adhering to the substrate surface during the alignment process, and these problems also depend on the cleanliness of the manufacturing site and manufacturing process.

An object of the present invention is to enable contact cleaning of the surface of an alignment film without adversely affecting alignment processing.

[Means to solve the problem]

The present invention will be explained with reference to FIGS. 1(a) and 1(b).

As shown in FIG. 2A, it is assumed that the surface of the alignment film formed on the substrate 1 is subjected to rubbing treatment in the direction shown by arrow I.

In the cleaning process after finishing the rubbing process, the cleaning process shown in Fig. 1 (b
), a scrubbing process is performed on the surface of this alignment film in the same direction as the above-mentioned rubbing process while flowing a cleaning liquid such as water.

The scrubbing process refers to rubbing the surface of the alignment film with something like a brush, cloth, or sponge. In the present invention, the direction of scrubbing is the same as the above-mentioned rubbing direction.

To do this, wrap a sponge, for example, around the surface of the cleaning roll 2, use this as the cleaning brush 3, and point the direction perpendicular to the axial direction of the cleaning roll 2 in the rubbing direction (arrow ■ in the figure).
In this state, the cleaning roll 2 is rotated in the direction of the arrow (2), and the surface of the alignment film is scrubbed with the rotating sponge.

The direction in which the sponge 3 rubs the alignment film surface now matches the rubbing direction. Therefore, the substrate 1 is moved relative to the cleaning roll 2 in the direction of the arrow (■).

In this way, the rubber ξ attached to the surface of the alignment film is
It is rubbed off with the sponge 3 and washed away with the running water, and the direction of rubbing with the sponge 3 is the direction of the arrow ■.
Matches the rubbing direction (arrow ■).

[For production]

As described above, since the scrubbing process rubs the surface of the alignment film, it has the same effect of defining the alignment direction as rubbing. However, in the present invention, as described above, the direction of the scrubbing process is made to match the direction of the rubbing process, so the alignment direction defined by the scrubbing process matches the alignment direction defined by the rubbing process, and the orientation process by rubbing There will be no adverse effects.

Therefore, according to the present invention, the adhered gobs can be effectively removed without any influence on the alignment process, and as a result, defects caused by the adhered gobs ξ can be significantly reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 2(a) to 2(d) show the orientation processing direction and scrubbing processing direction in one embodiment of the present invention. This example is a normal TN
This is an example in which the present invention is applied to a simple matrix panel using a type liquid crystal (twist angle 90'), and in FIG.

In this embodiment, since the twist angle is 90°, the rubbing directions of the common board and the segment board facing the common board are perpendicular to each other. In FIGS. 2(a) and 2(b) above, the surfaces on which the alignment films facing each other are formed are drawn upward, so the rubbing direction is 45° with respect to the side AB of the substrate l as shown. Intersect at ・In the common board, vertices A to C
On the segment board, the direction is conversely from C to A.

In this example, the substrate l is 300 x 250 x 1.1 m.
The alignment film was formed using a polyimide resin with a thickness of 0.1 μm by a transfer printing method.

The roll material (rubbing material) used for rubbing was rayon, and the contact depth was 400 μm. The cleaning brush 3 used in the scrubbing process was made of Bertalin material manufactured by KANEBO.

The scrub cleaning device used a belt conveyor that allowed substrates to flow one by one, and the scrubbing roll was tilted at 45 degrees with respect to the moving direction (arrow ■) of the belt conveyor. Further, during scrubbing, a water shower is continuously applied to the substrate.

In order to scrub the substrate surface in substantially the same direction as the orientation processing direction, it is sufficient that the moving speed of the substrate 1 is negligible compared to the rotational speed of the cleaning brush 3. Therefore, in this example, the diameter of the cleaning roll is 50 mm, the substrate moving speed is 5 mm/s, the roll rotation speed is 300 r, p, m,
I scrubbed twice.

The effects of this example are shown in FIG. 3 in comparison with those produced by the conventional method. The comparative sample was subjected to ultrasonic cleaning using isopropyl alcohol twice for 10 minutes. For both the sample manufactured by this conventional method and the liquid crystal display panel manufactured in this example, the gap thickness was 5 μm, and 10 panels were each manufactured in 60 pieces.

When this was evaluated for short circuits between the upper and lower substrates, in this example, only one out of a total of 60 panels was defective, as shown by the white circles, whereas in the sample manufactured using the conventional method, there was a black circle. As shown in the figure, defects occurred at around 20% for each loft, and a total of 11 sheets were defective.

As described above, the effect of the present invention is remarkable, and no difference was observed between the present example and the conventional method in terms of the orientation state.

In the above example, cleaning was performed by scrubbing after the rubbing, but instead of this, by taking advantage of the fact that the scrubbing itself has alignment processing ability, only the scrubbing was performed without any particular rubbing. You can also do it.

In this case, the scrubbing process serves as both an alignment process and a cleaning process.

As described above, in the present invention, the scrubbing process, which is a contact type cleaning method, can be performed without affecting the alignment process, and the gore ξ can be effectively removed.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to effectively remove attached dust without adversely affecting the alignment process, enabling a highly clean alignment process, and improving the manufacturing yield of liquid crystal display panels. will improve.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the principle of the present invention, FIG. 2 is a detailed explanatory diagram of the present invention, and FIG. 3 is an explanatory diagram of the effects of the present invention. In the figure, l is a substrate, 2 is a cleaning roll, 3 is a cleaning brush, 1. IV and V indicate the rubbing treatment direction, ■ indicates the rotation direction of the cleaning roll, and ■ indicates the moving direction of the substrate. The hand-printed version of the handbook was written by Harasha Kinmeikai (Ql).

Claims (2)

[Claims] (1) A liquid crystal display comprising the step of performing a rubbing process on the surface of an alignment film formed on a substrate, and then performing a scrubbing process on the surface of the alignment film in the same direction as the rubbing process direction while flowing a cleaning liquid. A method of manufacturing a display panel. (2) A liquid crystal display characterized by including a step of simultaneously performing cleaning and alignment treatment on the surface of the alignment film formed on the substrate by scrubbing the surface of the alignment film formed on the substrate in a predetermined direction while flowing a cleaning liquid. How to manufacture panels.