KR100476038B1 - LCD and its manufacturing method - Google Patents

Abstract

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device and a method of manufacturing the same, which can ensure a wide viewing angle over a whole area in a liquid crystal display device in which a counter electrode and a pixel electrode are formed on the same substrate.

The configuration of the present invention includes a thin film transistor that transmits a signal of a data line when a gate line is selected, a pixel electrode contacted with a drain electrode of the thin film transistor, and driven when the thin film transistor is operated, and on the same substrate as the pixel electrode. A first light-transmissive substrate including a counter electrode which is formed, induces an electric field parallel to the pixel electrode, and is divided into two portions by the pixel electrode, a second light-transmissive substrate facing the first light-transmissive substrate, and the first light-transmitting substrate; Located between the light-transmitting substrate and the second light-transmissive substrate, the liquid crystal is driven in a predetermined direction when a voltage is applied to the pixel electrode and the counter electrode, and formed on the top of the first light-transmissive substrate to have a domain of at least two constant direction when the liquid crystal is driven It is characterized by including a 1st alignment film.

Description

Liquid crystal display device and manufacturing method

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 securing a wide viewing angle in a whole in an IPS mode liquid crystal display device.

In general, liquid crystal display elements constitute display elements such as televisions and graphic displays, and especially active matrix type liquid crystal display devices have high-speed response characteristics, and are suitable for high pixel counts, thereby making display screens of high quality, large size, and color screens. It greatly contributes to the realization of money.

The liquid crystal display device includes a pair of transparent glass substrates, thin film transistors and pixel electrodes formed on at least one substrate, a color filter and a counter electrode formed on the other substrate, and a liquid crystal material between the pair of glass substrates. This is done by encapsulation.

Here, as the liquid crystals used in recent years, a twisted nematic mode (TN) liquid crystal having excellent optical characteristics is used, but the twisted nematic mode has a twist angle of 90 degrees, and the liquid crystal molecules are upper and lower glass. Since the array is arranged parallel to the substrate surface or the array direction is 90 ° difference between both substrates, the entire molecular array is arranged so that there is a continuous 90 ° change between the two substrates, and when the liquid crystal voltage is applied, the electric field It is formed perpendicular to the two substrate surfaces.

However, the liquid crystal display of the TN structure has a chronic problem of narrowing the viewing angle.

Therefore, conventionally, a counter electrode formed on the upper glass substrate is formed on the lower glass substrate so that a horizontal electric field is applied when an electric field is applied, so that a liquid crystal display device having an IPS mode capable of securing a wide viewing angle has been proposed. As shown in FIG. 1, the liquid crystal display of the IPS mode is formed on the same surface as the gate line 2A and the gate line 2A in the row direction for scanning an image on the lower glass substrate 1. Then, the counter electrode 2B spaced apart by a predetermined distance is formed. The counter electrode 2B serves as a storage capacitor for maintaining the liquid crystal for a predetermined time, and is formed to have a " □ " shape so as to define the shape of the unit cell. Although not shown in the drawings, a gate insulating film (not shown) is formed on the resultant to form electrical insulation between the lower gate line 2A and the materials to be formed later, and the gate line 2A is formed. The semiconductor layer 4 serving as a channel of the thin film transistor is formed on a predetermined portion of the gate insulating film. The data line 5A and the pixel electrode 5B are formed on the same plane, and the data line 5A intersects the gate line 2A perpendicularly and the semiconductor layer 4 on the gate line 2A. ) Overlaps a predetermined portion to form the source electrode 5A-1, and the pixel electrode 5B is formed in an "I" shape so that the space portion of the counter electrode 2B formed in a "□" shape is vertically divided. . The corner portion adjacent to the semiconductor layer 4 in this rectangular pixel electrode 5B extends to partially overlap the semiconductor layer 4 to become the drain electrode 5B-1.

FIG. 2 is a cross-sectional view of the above-described liquid crystal display element cut by the II-II 'line.

As shown in FIG. 2, an opaque metal film such as aluminum, tantalum, and molybdenum is deposited on the lower glass substrate 1, and the opaque metal film is patterned into a predetermined shape, so that the gate line 2A and the counter electrode 2B are formed. Is formed. Thereafter, the gate insulating film 3 is formed to a predetermined thickness on the lower glass substrate 1 so as to provide electrical insulation between the gate line 2A and the counter electrode 2B and the data line to be formed later. A semiconductor layer 4 made of amorphous silicon is formed on a predetermined portion of the gate insulating film 3 including 2A. Subsequently, an opaque metal film such as aluminum, tantalum, or molybdenum is deposited on the resultant portion, and predetermined portions are etched to form the source electrode 5A-1 and the drain electrode 5B-1.

In addition, the opposing upper glass substrate 20 is divided into color filters at positions corresponding to the thin film transistors of the lower glass substrate 1, and black is made of an opaque metal such as chromium to prevent deterioration of the thin film transistors. The matrix 21 is formed, and the color filter 22 with color is formed in the other parts.

On top of the lower glass substrate 1 and the upper glass substrate 20, alignment films 31 and 32 rubbed in a 180 ° direction are formed, respectively, to drive the liquid crystal in a predetermined direction, and the lower glass substrate 1 and Polarizing plates 41 and 42 are provided on the rear surface of the upper glass substrate 20 to deflect the incident light source, and the polarizing plates 41 and 42 are formed so that the directions of the light cross each other when the light is incident. Then, the lower glass substrate 1 and the upper glass substrate 20 are bonded in a known manner, and between the lower glass substrate 1 and the upper glass substrate 20, a liquid crystal having a negative or positive dielectric anisotropy is encapsulated. The liquid crystal display element is completed.

The liquid crystal display of the IPS mode as described above has the advantage that the counter electrode 2B and the pixel electrode 5B are formed on the same substrate, and thus a parallel electric field is formed, so that the viewing angle is excellent. In the liquid crystal display device, a gray scale inversion phenomenon occurs in part, and a certain part causes a disadvantage that the screen looks asymmetrical.

In addition, in the general liquid crystal display device, as shown in FIG. 4A, when an electric field is not applied, the liquid crystal molecules 50 between the upper and lower glass substrates 1 and 20 are divided at a 45 degree angle, and then an electric field is applied. As shown in FIG. 4B, the operation is performed in a 180 degree direction. Referring to this, when an electric field is applied, as shown in FIG. 3, the initial liquid crystal array is twisted at an angle of 45 degrees in the direction of 107 degrees, thereby becoming symmetric about the center of 152 degrees. However, in an area where the contrast ratio CR is 50, the screen becomes asymmetrical in the viewing angle, and an area where the CR in the 152 degree portion is 10 or less occurs, and in a gray scale inversion (for example, where a white screen is to be displayed), It can be seen from the drawing that the gray-angle phenomenon, which is indicated by G 'in FIG. 3B, is generated and the viewing angle is narrowed.

Accordingly, the present invention has been proposed to solve the above-mentioned problems. In the liquid crystal display device of the IPS mode, a liquid crystal display device capable of ensuring a wide viewing angle by preventing gray scale inversion from occurring over the entire area is produced. It is an object to provide a method.

In order to achieve the above object of the present invention, the present invention, in the selection of the gate line, the thin film transistor which transmits the signal of the data line, and the pixel electrode which is contacted with the drain electrode of the thin film transistor and is driven when the thin film transistor is operated. And a counter-transmitting substrate formed on the same substrate as the pixel electrode, inducing an electric field parallel to the pixel electrode, and including a counter electrode in which a space portion is divided by the pixel electrode, and facing the first translucent substrate. Located between the second light-transmitting substrate, the first light-transmissive substrate and the second light-transmissive substrate, the liquid crystal to be driven in a predetermined direction when the voltage is applied to the pixel electrode and the counter electrode, and to have a domain of at least two constant directions when driving the liquid crystal And a first alignment layer formed on an uppermost portion of the first light-transmitting substrate.

In addition, the method of manufacturing a liquid crystal display device of the present invention comprises the steps of: forming a gate line and a counter electrode on a transparent glass substrate; Forming a gate insulating film on the glass substrate; Forming a semiconductor layer on a predetermined portion of the gate insulating layer including the gate line; Depositing and patterning the metal layer to form a pixel electrode partially connected to the data line and the semiconductor layer; Forming an alignment layer on the resultant; And rubbing the alignment layer in a first direction: rubbing a predetermined portion of the alignment layer rubbed in the first direction in a second direction.

According to the present invention, at least two or more domains are formed in the liquid crystal display of the IPS mode, so that gray scale inversion does not occur even in a specific CR, thereby ensuring a wide viewing angle of the liquid crystal display.

EXAMPLE

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

5A to 5D are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to the present invention, and FIG. 6 is a view illustrating a relationship between a viewing angle and a contrast ratio of a liquid crystal cell according to the present invention, and the same parts as in the prior art. In the description, duplicate explanations are omitted, and the same reference numerals are given to the same parts as in the conventional drawings.

The present invention is to form at least two domains per unit cell of the liquid crystal display device to ensure a wide viewing angle in any area of the liquid crystal display device, to secure a wide viewing angle, two or more in the unit cell of the liquid crystal display device In order to form the domain, dust, the method of manufacturing the liquid crystal display device according to the present invention, as shown in Figure 5A, in the same manner as in the prior art, the lower glass on which the data line 5A and the pixel electrode 5B are formed A transparent alignment layer (not shown) is formed on the substrate to arrange the liquid crystals in a predetermined direction. This alignment film is then rubbed in the -45 ° direction by θ, preferably relative to the pixel electrode, with respect to the vertical axis of the " I " shaped pixel electrode 5B so that the first domain is formed.

Subsequently, a photoresist layer is formed on the alignment layer, and the photoresist layer is exposed and etched to expose the X region in FIG. 5A, and a mask 60 is formed. Then, as shown in FIG. 5B, the alignment layer corresponding to the exposed X region is formed. The second domain is formed by rubbing at a 45 ° angle with respect to the vertical axis of the pixel electrode 5B.

FIG. 5C is a view in which the mask 60 is removed. In the liquid crystal display device, two domains are formed, and the viewing angle of the liquid crystal display device is enlarged. Also, the pixel electrode 5B is disposed at the boundary between the first domain and the second domain. ), A phenomenon such as light leakage is prevented.

In the liquid crystal display element thus formed, the area where CR is 10 and gray scale inversion do not occur, and the viewing angle is also extended.

As described in detail above, according to the present invention, in order to prevent the viewing angle and the gray scale inversion phenomenon of the liquid crystal display of the IPS mode, the alignment layer is formed such that at least two domains are formed on the vertical side of the pixel electrode. By rubbing, the viewing angle of the liquid crystal display element can be enlarged, and a phenomenon such as gray scale inversion can be prevented to improve the quality of the liquid crystal display element.

1 is a plan view showing a liquid crystal display device of the conventional IPS mode.

FIG. 2 is a cross-sectional view of the liquid crystal display of FIG. 1 taken along line II-II '. FIG.

3A is a diagram showing a relationship between a viewing angle and a contrast ratio of a liquid crystal display device of the conventional IPS mode.

Fig. 3B is a diagram showing a gray scale inversion of a liquid crystal display device of the conventional IPS mode.

4A and 4B are views for explaining the operation of liquid crystals depending on whether an electric field is applied to a general liquid crystal display element.

5A to 5C are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to the present invention.

* Description of the symbols for the main parts of the drawings *

1-Glass Substrate 2A-Gate Line

2B-counter electrode 3-gate insulating film

4- semiconductor layer 5A-data line

5B-1-Drain Electrode 20-Top Board

21-black matrix 22-color filter

31,32-alignment film 41,42-polarizing plate

50-liquid crystal

Claims (6)

When the gate line is selected, a thin film transistor for transmitting a signal of the data line, a pixel electrode contacted with the drain electrode of the thin film transistor and driven when the thin film transistor is operated, and formed on the same substrate as the pixel electrode, A first light-transmitting substrate inducing a parallel electric field and including a counter electrode having a space divided by the pixel electrode; A second light transmissive substrate facing the first light transmissive substrate, A liquid crystal positioned between the first light transmissive substrate and the second light transmissive substrate and driven in a predetermined direction when a voltage is applied to the pixel electrode and the counter electrode; And a first alignment layer formed on an uppermost portion of the first light-transmitting substrate to have a domain in at least two constant directions when driving the liquid crystal. The liquid crystal display of claim 1, wherein the domains are divided into domains having two directions with respect to the pixel electrode of the first light-transmissive substrate. The liquid crystal display of claim 1, wherein the two domains have an angle difference of 90 degrees with each other and are symmetrical with respect to the pixel electrode. Forming a gate line and a counter electrode on the transparent glass substrate; Forming a gate insulating film on the glass substrate; Forming a semiconductor layer on a predetermined portion of the gate insulating layer including the gate line; Depositing and patterning the metal layer to form a pixel electrode partially connected to the data line and the semiconductor layer; Forming an alignment layer on the resultant; Rubbing the alignment layer in a first direction; And rubbing a predetermined portion of the alignment film rubbed in the first direction in the second direction. The method of claim 4, wherein in the rubbing of the alignment layer in a first direction, the first direction is a 45-degree direction with respect to the pixel electrode. The method of claim 4, wherein the rubbing of a predetermined portion of the alignment layer rubbed in the first direction comprises: forming a mask pattern on an alignment layer so as to cover any one of the portions divided by the pixel electrode; Rubbing the alignment layer such that the exposed surface has an angle difference of 90 degrees with a first direction; And removing the mask pattern.