KR19990050945A - Rubbing process of liquid crystal display device - Google Patents

Abstract

The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to a rubbing process of a liquid crystal display device to align the liquid crystal molecules in a predetermined direction. In the rubbing process of the liquid crystal display device according to the embodiment of the present invention, in a state where a polyimide film is coated on a glass substrate, the polyimide film is cured at a predetermined temperature, and then high pressure air or water is sprayed onto the cured polyimide film at a predetermined angle. The surface molecules of the polyimide film are stretched in a predetermined direction.

Description

Rubbing process of liquid crystal display device

The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to a rubbing process of a liquid crystal display device for arranging liquid crystal molecules in a predetermined direction.

In general, a liquid crystal display includes a lower glass substrate on which a thin film transistor, which is an individual switching element, and three color filters of red, green, and blue are formed. The repeated and arranged upper glass substrates are bonded together, and the liquid crystal is enclosed in the space between the glass substrates.

Meanwhile, the liquid crystal display device having such a structure coats an alignment layer as a top layer on each substrate in order to arrange liquid crystal molecules injected between upper and lower substrates in a predetermined direction. This is because it depends greatly on the state of molecular arrangement, and also has a difference in response to external forces such as an electric field depending on the state of molecular arrangement.

In other words, it is difficult to obtain the same molecular arrangement state simply by interposing between upper and lower glass substrates, so that the liquid crystal molecules must be subjected to some kind of processing on the inner wall of the substrate. Therefore, for this purpose, it is common to form an alignment film on each of the upper and lower glass substrates. The alignment film is usually formed by surface-treating the cured polyimide film so that the surface molecules of the polyimide film are stretched in a predetermined direction.

1 is a view for explaining a rubbing process of the liquid crystal display device according to the prior art.

As shown in the drawing, the rubbing process hardens the polyimide film at a predetermined temperature in a state where a polyimide film having a predetermined thickness is coated on the glass substrate 1, and then nylon or rayon or the like is applied to the cured polyimide film 2. The rubbing roller 10 coated with the same rubbing cloth 10a is rubbed in a predetermined direction, whereby the surface molecules (not shown) of the cured polyimide film 2 are moved in a predetermined direction. Stretched.

2A and 2B are diagrams for explaining the state of surface molecules of the polyimide film according to the rubbing process, FIG. 2A is a view showing the polyimide film before the rubbing process, and FIG. 2B is a view showing the polyimide film after the rubbing process. to be.

As shown in FIG. 2A, the surface molecules 2a of the polyimide film 2 before the rubbing process are randomly arranged without a certain direction, and the liquid crystal molecules are not arranged in the same direction on the alignment film. . On the other hand, as shown in Fig. 2B, in the case of the polyimide film 2 subjected to the rubbing process, the surface molecules 2a thereof are stretched in a constant direction.

Therefore, when the liquid crystal molecules are placed on the polyimide film subjected to the rubbing process, as shown in FIG. 3, the liquid crystal molecules 4 are in the direction in which the surface molecules 2a of the polyimide film 2 are drawn. It is arranged regularly along.

However, since the rubbing process according to the prior art as described above, since the rubbing cloth remains on the alignment layer after the completion of the process, a cleaning process must be performed to remove the rubbing cloth, and thus, the overall process has a complicated problem. .

In addition, since the rubbing cloth has a life time, there is a problem that productivity is reduced due to additional processes such as replacement of the rubbing cloth.

Accordingly, an object of the present invention is to provide a rubbing process for a liquid crystal display device capable of simplifying the rubbing process and improving productivity.

1 is a view for explaining a rubbing process of a liquid crystal display device according to the prior art.

2A and 2B are views for explaining states of surface molecules of a polyimide film according to a rubbing process.

3 is a view for explaining an arrangement state of liquid crystal molecules on an alignment layer subjected to a rubbing process.

4 is a view for explaining a rubbing process of the liquid crystal display device according to an embodiment of the present invention.

(Explanation of symbols for the main parts of the drawing)

1: glass substrate 2: polyimide film

20: high pressure nozzle

In order to achieve the above object, the present invention is a state in which the polyimide film is coated on a glass substrate, and then cured at a predetermined temperature, and then the high pressure air or water is sprayed onto the cured polyimide film at a predetermined angle. The surface molecules of the membrane are stretched in a certain direction.

According to the present invention, since high-pressure air or water is injected into the cured polyimide film at a predetermined angle, the surface molecules of the polyimide film can be aligned in a predetermined direction.

Hereinafter, with reference to the accompanying Figure 4 will be described in detail a preferred embodiment of the present invention.

4 is a view for explaining a rubbing process of the liquid crystal display device according to an embodiment of the present invention. Here, the same parts as in Fig. 1 are denoted by the same reference numerals.

First, in a state where a polyimide film having a predetermined thickness is applied on the glass substrate 1, the applied polyimide film is cured at a predetermined temperature, and then the polyimide film cured from the high pressure nozzle 20 as shown in the drawing. (2) is sprayed with high pressure water or air at a predetermined angle.

As a result, the surface molecules (not shown) of the cured polyimide film 2 are stretched in a predetermined direction by the high pressure air or water to be injected, and at the same time, the high pressure air or water injected from the spray nozzle 20 The stretching direction of the surface molecules of the polyimide film is variously controlled according to the spraying angle.

Therefore, in the conventional rubbing process using a rubbing roll coated with a rubbing cloth, the rubbing cloth remains on the alignment film, but when using high pressure air or water, foreign matter does not remain on the alignment film, so that the cleaning process can be eliminated. Accordingly, the rubbing process can be simplified.

In addition, the rubbing cloth has a certain lifetime, but since high pressure air or water can be supplied as long as the equipment is running, it is possible to prevent productivity deterioration due to the replacement of the rubbing cloth.

As described above, in the rubbing process of the liquid crystal display device of the present invention, instead of using a rubbing roll coated with a rubbing cloth, an alignment layer is manufactured using high-pressure air or water, thereby eliminating the cleaning and replacing rubbing cloth. Thereby, while simplifying a rubbing process, productivity can be improved.

Meanwhile, although specific embodiments of the present invention have been described and illustrated, modifications and variations can be made by those skilled in the art. Accordingly, the following claims are to be understood as including all modifications and variations as long as they fall within the true spirit and scope of the present invention.

Claims (2)

A rubbing process of a liquid crystal display device for stretching the surface molecules of the cured polyimide film in a certain direction so that the liquid crystal molecules are oriented in a predetermined direction, wherein a high-pressure air or water is applied from the high pressure nozzle to the cured polyimide film at a predetermined angle. The rubbing process of the liquid crystal display element characterized by spraying. The rubbing process of a liquid crystal display device according to claim 1, wherein the stretching direction of the surface molecules of the polyimide film is adjusted according to an injection angle of high pressure air or water injected from the high pressure nozzle.