KR100683136B1 - Manufacturing Method of Liquid Crystal Display - Google Patents

Abstract

The present invention discloses a method of manufacturing a liquid crystal display device capable of having a fast response characteristic while improving viewing angle characteristics without the hassle of processes, and the disclosed invention provides that each pixel includes four first to fourth domains. Preparing upper and lower substrates divided into formation regions; Applying a first horizontal alignment layer having a negative pre-tilt angle to each of the first domain formation regions of the upper and lower substrates and rubbing them in a first direction; A second horizontal alignment layer having a positive (+) pretilt angle is applied to each of the third domain formation regions disposed diagonally to the first domain formation regions of the upper and lower substrates, and is perpendicular to the first direction. Rubbing in a second direction; First and second regions each of the second domain formation regions adjacent to the first domain formation regions of the upper and lower substrates and the fourth domain formation regions disposed diagonally to the second domain formation regions. Applying a vertical alignment layer and rubbing them in directions giving opposite pretilt angles to each other to prevent reverse tilt domains, wherein the first to fourth domain forming regions in the lower substrate and the upper substrate The first to fourth domain formation regions in the Equation 4 may have different alignment layer types and rubbing treatments in different directions between the domain formation regions facing each other so that each of the four domains in one pixel may have a different alignment state. It features.

Description

Manufacturing method of liquid crystal display device {METHOD FOR MANUFACTRUING LIQUIDE CRYSTAL DISPLAY DEVICE}

1A to 1C are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to the present invention.

1D is a view showing a liquid crystal alignment state in a liquid crystal display device manufactured according to the present invention.

Explanation of symbols on the main parts of the drawings

10: upper substrate 20: lower substrate

30a, 30a ': first horizontal alignment layer 30b, 30b; : 1st vertical alignment film

30c, 30c ': second horizontal alignment film 30d, 30d': second vertical alignment film

40: liquid crystal molecules

The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to a method for manufacturing a liquid crystal display device capable of improving viewing angle characteristics and response speed.

In general, a thin film transistor liquid crystal display (TFT-LCD) may implement a display, which may be miniaturized in volume compared to a conventional cathode ray tube (CRT), and may use low power consumption. However, such a thin film transistor liquid crystal display device has a front viewing angle comparable to that of a CRT, but is not excellent in an oblique direction. The change in the viewing angle in this way depends on the refractive index anisotropy of the liquid crystal molecules constituting the liquid crystal layer, as is known.

The viewing angle of a conventional notebook (Note-Book) PC consisting of a liquid crystal display device is the best specification about 45 degrees left and right, 20 degrees upper, 40 degrees lower. In addition, the response speed is slow to 40 ~ 60msec. This is known as the general limitation of Normal Twist Nematec (TN).

In order to solve this problem, a vertical alignment (VA) mode and an in plan field (IPS) mode liquid crystal display have been conventionally proposed.

First, the configuration of the VA mode is as follows.

A liquid crystal layer having a negative dielectric anisotropy is interposed between upper and lower substrates each having an electrode, and vertical alignment layers are respectively provided on inner surfaces of the upper and lower substrates, respectively. This VA mode has the advantage of excellent response speed characteristics.

On the other hand, the IPS mode is configured as follows.

The upper and lower substrates face each other at a predetermined distance. The liquid crystal layer is interposed in the space between the upper and lower substrates, and the pixel electrode and the counter electrode are disposed at a predetermined interval on the lower substrate. At this time, the distance between the pixel electrode and the counter electrode is larger than the distance between the upper and lower substrates. Horizontal alignment layers are respectively provided on the inner surface of the lower substrate and the upper substrate. In the IPS mode, an electric field formed between the pixel electrode and the counter electrode is formed in parallel with the lower substrate surface, thereby improving the viewing angle characteristic.

 However, the above-described IPS mode has excellent viewing angle characteristics but very slow response speed, which makes it difficult to use for realizing moving images.

In addition, the VA mode has a problem in that the response speed is excellent while the viewing angle is narrow.

Accordingly, in another conventional method, in order to secure the side viewing angle of the VA mode liquid crystal display, a method of forming two or more domains through at least four vertical alignment film rubbing processes in one pixel has been proposed. However, this method is very cumbersome because at least one photolithography process and a rubbing process must be performed on at least one alignment film.

Accordingly, the present invention has been made to solve the above-described conventional problems, and by forming four domains in one pixel without further photolithography process to improve the viewing angle characteristics without the hassle of the process to have a fast response characteristics It is an object of the present invention to provide a method for manufacturing a liquid crystal display device.

In order to solve the above problems, the present invention comprises the steps of providing an upper substrate, a lower substrate, each pixel is divided into four first to fourth domain formation regions; Applying a first horizontal alignment layer having a negative pre-tilt angle to each of the first domain formation regions of the upper and lower substrates and rubbing them in a first direction; A second horizontal alignment layer having a positive (+) pretilt angle is applied to each of the third domain formation regions disposed diagonally to the first domain formation regions of the upper and lower substrates, and is perpendicular to the first direction. Rubbing in a second direction; First and second regions each of the second domain formation regions adjacent to the first domain formation regions of the upper and lower substrates and the fourth domain formation regions disposed diagonally to the second domain formation regions. Applying a vertical alignment layer and rubbing them in directions giving opposite pretilt angles to each other to prevent reverse tilt domains, wherein the first to fourth domain forming regions in the lower substrate and the upper substrate The first to fourth domain formation regions in the Equation 4 may have different alignment layer types and rubbing treatments in different directions between the domain formation regions facing each other so that each of the four domains in one pixel may have a different alignment state. A method of manufacturing a liquid crystal display device is provided.

Here, the first to fourth domain forming regions are each made of a polyimide-based polymer compound and are coated with an alignment film having different physical properties, and are rubbed by a photo-alignment method using UV.

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(Example)

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
1A to 1C are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to the present invention.

Referring to FIG. 1A, one pixel is divided into first to fourth domain forming regions, for example, A, B, C, D and domain forming regions of A ', B', C ', and D'. Prepared upper and lower substrates 10 and 20. At this time, the domain forming regions of A, B, C, D in the upper substrate 10 and the domain forming regions of A ', B', C ', and D' in the lower substrate 20 are finally obtained. Facing domain forming regions are set to be disposed at different positions so that each domain has a different orientation state.

Referring to FIG. 1B, first horizontal alignment layers 30a and 30a 'having negative (−) pretilt angles may be selectively formed on the A and A ′ domain forming regions of the inner surfaces of the upper and lower substrates 10 and 20. Apply. Here, the selective application of the alignment film in a specific region can be performed using a mask or the like according to a known technique. Then, the first horizontal bang facing films 30a and 30a 'are subjected to a rubbing treatment in a first direction by using a UV alignment method. Subsequently, a second horizontal alignment layer 30c having a positive (+) pretilt angle in each of the C and C ′ domain forming regions diagonally disposed in the A domain forming regions on the inner surfaces of the upper and lower substrates 10 and 20. , 30c '), and then the second horizontal bang facing films 30c and 30c' are subjected to a rubbing treatment in a second direction perpendicular to the first direction using a photoalignment method using UV.
Here, the pre-tilt angle means that the liquid crystal molecules having a rod type in the initial state without a voltage are applied so that their major axis is slightly raised clockwise or counterclockwise with respect to the horizontal plane. Having the negative (-) free tilt angle means that the liquid crystal molecules have their long axes slightly raised in the clockwise direction, and having the positive (+) free tilt angle means that the liquid crystal molecules have their long axes slightly counterclockwise. To be excited.

Referring to FIG. 1C, B and B ′ domain forming regions adjacent to each of the A and A ′ domain forming regions of the inner side of the upper and lower substrates 10 and 20, and D and D ′ domains disposed diagonally thereto. The first vertical alignment films 30b and 30b 'and the second vertical alignment films 30d and 30d' are selectively applied to each of the formation regions. Then, the optical alignment method using UV in the direction in which the first and second vertical alignment layers 30b, 30b ', 30d, and 30d' are provided with opposite pretilt angles to each other to prevent reverse tilt domains. Each rubbing process.
Here, the pretilt angle means that the liquid crystal molecules standing vertically are inclined slightly in a clockwise or counterclockwise direction with respect to the vertical plane in order to lie in either a clockwise or counterclockwise direction when voltage is applied. In the C and C 'domain forming regions, the long axis of the liquid crystal molecules is counterclockwise, and in the D and D' domain forming regions, the long axis of the liquid crystal molecules is slightly inclined clockwise.
Meanwhile, the present invention allows the alignment layers formed in the respective domain formation regions on the inner surfaces of the upper and lower substrates 10 and 20 to be subjected to different alignment layer types and rubbing treatments in different directions between the domain formation regions facing each other. Each of the four domains formed in one pixel has a different alignment state.
For example, the first horizontal alignment layer 30a is formed in the A domain formation region of the upper substrate 10, and the second vertical alignment layer 30d ′ is formed in the D ′ domain formation region of the lower substrate 20 facing the same. And a second horizontal alignment layer 30c in the C domain formation region in the upper substrate 10, and a second vertical alignment layer 30b 'in the B ′ domain formation region in the lower substrate 20 facing the same. And a first vertical alignment layer 30b in the B domain formation region in the upper substrate 10, and a first horizontal alignment layer in the A ′ domain formation region in the lower substrate 20 facing the same. 30a '), and a second vertical alignment film 30d is formed in the D domain forming region in the upper substrate 10, and the second horizontal alignment film is formed in the C' domain forming region in the lower substrate 20 facing the same. 30c 'is formed.

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1D is a view showing a liquid crystal alignment state in the liquid crystal display according to the present invention manufactured as described above.
As shown, one pixel constitutes four domains, each domain representing a different liquid crystal alignment state. For example, the liquid crystal molecules 40 are vertically disposed with respect to the B domain disposed on the inner surface of the upper substrate 10, and the liquid crystal molecules 40 are disposed with respect to the A ′ domain disposed on the inner surface of the lower substrate 20. ) Are arranged in parallel so that the liquid crystal molecules 40 are oriented in a hybrid molecular arrangement.

As described in detail above, the present invention divides one pixel into four domains and uses optical alignment to have different alignment states without a photolithography (= mask) process, thereby securing a wide viewing angle and vertical alignment. Fast response speed, which is an advantage, can be achieved and process simplification can be achieved.

Accordingly, the liquid crystal display of the present invention can expect the effect of securing competitiveness and increasing marketability with excellent image quality.

In addition, this invention can be implemented in various changes within the range which does not deviate from the summary.

Claims (3)

Preparing upper and lower substrates each of which one pixel is divided into four first to fourth domain forming regions; Applying a first horizontal alignment layer having a negative pre-tilt angle to each of the first domain formation regions of the upper and lower substrates and rubbing them in a first direction; A second horizontal alignment layer having a positive (+) pretilt angle is applied to each of the third domain formation regions disposed diagonally to the first domain formation regions of the upper and lower substrates, and is perpendicular to the first direction. Rubbing in a second direction; First and second regions each of the second domain formation regions adjacent to the first domain formation regions of the upper and lower substrates and the fourth domain formation regions disposed diagonally to the second domain formation regions. Applying a vertical alignment film and rubbing them in directions giving opposite pretilt angles to each other; The first to fourth domain formation regions of the lower substrate and the first to fourth domain formation regions of the upper substrate may have different alignment layer types and rubbing treatments in different directions between the domain formation regions facing each other. A method of manufacturing a liquid crystal display device, wherein each of the four domains in one pixel has a different alignment state. The liquid crystal display according to claim 1, wherein the first to fourth domain formation regions are each made of a polyimide-based polymer compound and coated with an alignment film having different physical properties, and rubbed by a photo alignment method using UV. Method of manufacturing the device. delete

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