KR100243038B1 - Gas-knife alignment apparatus and method for producing alignment layer using thereof - Google Patents

Abstract

An alignment film forming method of the present invention comprises the steps of providing a substrate, applying a polymer film such as polyimide (PI) to the substrate, and injecting a gas into the substrate using a gas knife alignment apparatus.

The gas knife alignment apparatus according to the present invention is provided with a gas knife, a gas injection hole formed in the gas knife, and equipped with a pressure sensor for pressure regulation and injecting gas, and connected to the gas knife to supply gas. It consists of a gas inlet.

Description

Gas knife alignment device and method for forming alignment film using same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas knife alignment device, and more particularly, to a gas knife alignment device and a method for forming an alignment film by injecting a gas in order to form an alignment film for liquid crystal alignment.

In general, a liquid crystal alignment film of a twisted nematic liquid crystal display device (TN-LCD) is disposed inside the transparent electrode and directly contacts liquid crystal molecules. In the interface of the liquid crystal alignment film and the liquid crystal molecules, the alignment of the liquid crystal molecules is expressed by the uniaxial alignment of the liquid crystal molecules by the uniaxial stretching method of the liquid crystal alignment film and the angle (pretilted angle) between the liquid crystal alignment film and the liquid crystal molecules. It is possible.

As a means for uniaxially stretching the liquid crystal alignment film, a mechanical stretching, a Langmuir-Blodgett method, a rubbing method, and the like have been proposed. Among them, the conventional rubbing method is a simple method of rubbing a substrate coated with a polymer with a cloth, which is widely used industrially because of its large area and high-speed processing.

1 is a view showing the operation of rubbing orientation of the substrate using a conventional roller. The conventional rubbing method first provides a substrate 1 to which a color filter or TFT is attached, and then forms an alignment layer 10 by applying a polymer film such as polyimide (PI) or polyvinyl alcohol (PVA) to the substrate. . The roller 20 winds and attaches the oriented cloth 23 made of fiber, such as nylon and polyester, to the cylindrical roll 21. As shown in FIG. A method of mechanically rubbing the substrate surface in an arbitrary direction by placing the substrate 1 in a substrate transfer device (not shown) to move in the substrate advancing direction 40 and rotating the roller 20. to be.

When the substrate is rubbed by the above-described method, the liquid crystal molecules are oriented in the stretching direction of the PI chain by Van der Waals force between the liquid crystal alignment layer and the liquid crystal molecules, and the excluded volume effect Thus, the liquid crystal molecules are arranged in accordance with the PI chain changed on the liquid crystal alignment film so that its exclusion volume is minimized. From this, the liquid crystal molecules exhibit orientation along the rubbing direction, and the pretilt angle of the liquid crystal molecules is generated in the rubbing direction.

By the above rubbing process, uniform micro grooves are formed in the alignment layer. The microgrooves arrange liquid crystal molecules in parallel with the microgrooves so as to minimize the elastic deformation energy. However, in the above rubbing process, since the shape of the microgrooves formed in the alignment layer varies according to the frictional strength of the alignment cloth and the alignment layer, the arrangement of liquid crystal molecules becomes non-uniform, resulting in phase distortion and light scattering. These phase distortions and light scattering can have a significant impact on LCD performance.

As a method for reducing the above effects, the characteristics of the alignment cloth should have a high seeding density per unit area, a uniform fiber length, a narrow fiber diameter, and low generation of static electricity during rubbing. In addition, the glass transition point should be high, the generation of less impurities, less fibers, less of the inner pool, etc. should be.

However, in the conventional rubbing method, since the value of the pretilt angle fluctuates slightly depending on the film forming condition or the rubbing condition, sufficient consideration is required in the realization thereof. In addition, since the polymer film is rubbed with an alignment cloth, there is a problem of generation of fine dust or generation of electrostatic discharge (ESD) by high pressure static electricity. Dust is a major obstacle in the process of forming a thin film transistor (TFT) by repeating a high definition pixel electrode, film formation, exposure and etching. Local discharge causes damage to the alignment film itself, disconnection of the transparent electrode or TFT, and electrostatic destruction. In addition, the TFT alignment film is also required to have a property of having a high voltage storage ratio, which can maintain charge charge for a long time.

In addition, in the operation mode, when the roller is rotated at a high revolution per minute (rpm), the alignment cloth is separated by the centrifugal force. In addition, the lifespan of the alignment cloth is short and the nonuniformity of many tiles of the cloth itself can not be inspected, and the alignment nonuniformity and the orientation scratches due to the step generated during the formation of a color filter or a TFT substrate are not possible. ), There is a problem that the non-orientation unit is generated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide a gas knife alignment apparatus and an alignment film forming method, in particular, which inject a gas to orient the alignment film.

In order to achieve the above object, a gas knife alignment apparatus according to the present invention includes a gas knife, a gas injection hole formed in the gas knife, and equipped with a pressure sensor for pressure regulation and injecting gas into the gas knife; It is composed of a gas inlet for supplying gas.

The method for forming an alignment film of the present invention includes providing a substrate, applying a polymer film such as PI to the substrate, and injecting a gas into the substrate using a gas knife alignment device.

BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing which shows the operation | work rubbing orientation of a board | substrate using the conventional roller.

Fig. 2 is a cross-sectional view showing an operation of forming an alignment film using a gas knife alignment device for injecting the gas of the present invention.

3 is a front view showing a gas knife alignment device of the present invention.

Explanation of symbols on the main parts of the drawings

1, 100: substrate 10, 110: alignment film

20: roller 21: roll

23: alignment cloth 40: direction of travel of the substrate

70: rotation direction of the roller 200: gas knife alignment device

210: gas knife 240: gas injection hole

270 gas injection port 300 gas injection direction

Hereinafter, with reference to the accompanying drawings will be described in detail a gas knife alignment apparatus and an alignment film forming method according to the present invention.

FIG. 2 is a view showing an operation of forming an alignment film using a gas knife alignment device for injecting the gas of the present invention, and FIG. 3 is a front view of the above-described gas knife alignment device.

In the same figure, the gas knife alignment apparatus 200 of the present invention is connected to the gas knife 210, the gas injection hole 240 formed in the gas knife to inject the gas, and the gas knife It is composed of a gas inlet 270 for supplying gas. The gas injection hole 240 is equipped with a pressure sensor (not shown), it is possible to adjust the pressure of the gas extensively, and the direction of the injected gas can be freely adjusted from 0 ° to 360 °. The gas may be ordinary air.

In addition, a method of forming an alignment layer using the gas knife alignment apparatus of the present invention may include providing a substrate 100 to which a color filter or a TFT is attached, and applying a polymer film such as PI to the substrate. And forming an alignment layer 110 by injecting a gas into the gas knife alignment apparatus 200 on the substrate.

When the alignment film is formed by the above method, the problem in the rubbing method using a conventional alignment cloth can be solved at various angles. First, since the rubbing cloth and the substrate on which the alignment layer is formed are not in direct contact with each other, the alignment defect is reduced. Second, since the gas used is not particularly limited, the cost can be reduced compared to the case of manufacturing and using the alignment cloth. Third, gas injection As the pressure sensor of the hole, the pressure of the gas can be freely adjusted to appropriately adjust the alignment degree of the alignment film. Fourth, the alignment angle of the alignment film can be adjusted by adjusting the injection time.

The present invention, as described above, by forming the alignment film using a gas knife alignment apparatus for injecting gas, not only can reduce defects due to non-uniform alignment cloth, but also can reduce the cost. By not using the alignment cloth, there is no problem caused by dust, static electricity, etc. generated on the substrate other than the defect of the alignment cloth itself, and the occurrence of scratches and non-orientation parts caused by the protrusions of the substrate are completely eliminated. It can be minimized. Therefore, there is an effect that can solve the fundamental problems such as phase distortion and light scattering due to non-uniformity of the liquid crystal molecules.

Claims (5)

Gas knife, A gas injection hole formed in the gas knife to inject gas; A gas knife alignment device comprising a gas injection port connected to the gas knife to supply gas. 2. The gas knife alignment device according to claim 1, wherein a pressure sensor for pressure adjustment is mounted in the gas injection hole. The gas knife alignment apparatus according to claim 1, wherein said gas is air. Providing a substrate, Applying a polymer film to the substrate; And injecting gas into the substrate with a gas knife aligning device. The method of claim 4, wherein the polymer film is PI (polyimide).

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