KR20090032333A - Liquid crystal display device and method of manufacturing the same - Google Patents

Abstract

A liquid crystal display and a manufacturing method thereof are provided to prevent the lowering of the luminance around a peripheral region of a data line by arranging a liquid crystal of the peripheral region of a data line by a transverse electric field of the outermost pixel electrode and a second common electrode. A gate line and a data line(110) define a pixel region on a substrate. A first common electrode(170a) is equipped in the pixel region of the substrate in a flat shape. A pixel electrode of a slit shape corresponds to the first common electrode while interposing a protective layer. A second common electrode(170b) is separated from the pixel electrode and is overlapped with a data line. The second common electrode is prepared on the pixel electrode and is made of the same material.

Description

Liquid crystal display and its manufacturing method {LIQUID CRYSTAL DISPLAY DEVICE AND METHOD OF MANUFACTURING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device and a method of manufacturing the same, which can improve aperture ratio and improve luminance.

Liquid crystal display devices (liquid crastal display device) is due to the characteristics of light weight, thin, low power consumption driving, the application range is gradually increasing. In accordance with this trend, the liquid crystal display is used in office automation equipment, audio / video equipment, and the like.

The liquid crystal display displays an image by changing an electrical signal into visual information by using a characteristic in which light transmittances of liquid crystals, which are intermediate states of liquid and crystal, vary according to an applied voltage. A typical liquid crystal display device is composed of two substrates provided with electrodes and a liquid crystal layer interposed between the two substrates. Such a liquid crystal display device is lighter in weight, smaller in volume, and operates with less power than other display devices having the same screen size.

Representative liquid crystal display device has a problem that the TFT (thin film transistor) liquid crystal display device has a narrow viewing angle. In order to solve this problem, a multi-domain structure, an optically compensated birefringence (OCB) mode, an in plane switching (IPS) mode, and the like have been proposed. However, the multi-domain structure has a complicated process of forming a multi-domain, and there is a limit in improving the viewing angle. The OCB mode has excellent electro-optical performance in terms of viewing angle and response speed, but has a disadvantage in that it is difficult to stably control and maintain a liquid crystal by a bias voltage. The IPS mode is suitable for a large area liquid crystal display and has a wide viewing angle, but has a low aperture ratio.

In order to improve the aperture ratio and transmittance of the liquid crystal display, a fringe field switching (FFS) mode liquid crystal display has been proposed.

The FFS mode LCD has a structure in which a common electrode and a pixel electrode are overlapped with each other in a state where an insulator is interposed on one substrate. The common electrode corresponds to the pixel region in a flat form, and the pixel electrode is provided on the common electrode in a slit form in which a plurality of rod-shaped patterns are spaced apart from each other. Unlike the IPS mode, the FFS mode has a transverse electric field at several 수 intervals, so the transverse electric field is strong, and the liquid crystal molecules on the electrode can be arranged by the transverse electric field. In addition, since the 2 ITO structure, the white luminance can be increased to increase the aperture ratio.

However, the conventional FFS mode liquid crystal display has a problem in that light leakage occurs in the outer region (the black matrix region of the color filter substrate) of the common electrode and the pixel electrode, thereby reducing the luminance in the outer region of the pixel. In more detail, in the conventional FFS mode liquid crystal display, since the lateral electric field is weak in the outer regions (peripherals of the data lines) of the common electrode and the pixel electrode, the luminance is lowered compared to the center region of the pixel.

In addition, when a wide area of the black matrix is formed in order to improve light leakage in the outer region (data line peripheral part) of the pixel, there is a problem that the aperture ratio is lowered accordingly.

It is also an object of the present invention to provide a liquid crystal display device and a method of manufacturing the same, which can increase the aperture ratio of the present invention and improve luminance.

Liquid crystal display device according to an embodiment of the present invention,

Board; A gate line and a data line defining a pixel area on the substrate;

A first common electrode provided in a flat shape in the pixel area of the substrate; A slit pixel electrode provided to correspond to the first common electrode with a protective layer interposed therebetween; And a second common electrode spaced apart from the pixel electrode at a predetermined interval and overlapping a portion of the data line.

In addition, the manufacturing method of the liquid crystal display device according to another embodiment of the present invention,

Forming a gate electrode and a gate line on the substrate; Forming a gate insulating film on the substrate including the gate electrode; Forming a first common electrode on the gate insulating film; Forming a semiconductor layer, a source / drain electrode, and a data line on the gate insulating film; Forming a passivation layer on the gate insulating layer including the source / drain electrode, the first common electrode, and the data line; And forming a pixel electrode on the passivation layer and connected to the drain electrode, and a second common electrode spaced apart from the pixel electrode by a predetermined distance.

According to an embodiment of the present invention, a second common electrode overlapping a data line partially spaced apart from a slit-shaped pixel electrode corresponding to a first common electrode having a flat shape is provided, and thus the outermost part of the pixel electrode (adjacent to the second common electrode) is provided. The liquid crystal of the peripheral area of the data line is arranged by the transverse electric field of the pixel electrode and the second common electrode provided in the present invention, thereby reducing the luminance of the peripheral area of the data line.

In addition, the present invention has a structure that can minimize the black matrix area of the color filter substrate corresponding to the data line by improving the decrease in luminance of the peripheral area of the data line, thereby increasing the aperture ratio of the liquid crystal display device. There is.

In addition, according to the present invention, a second common electrode is provided to partially overlap the data line and serves as a shield to improve electrical interference between the data line and the pixel electrode, thereby degrading image quality due to electrical interference between the data line and the pixel electrode. There is an additional effect to improve the.

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

1 is a plan view illustrating a thin film transistor substrate of a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view of the thin film transistor substrate cut along lines II ′ and II-II ′ of FIG. 1.

1 and 2, the thin film transistor substrate of the liquid crystal display according to the exemplary embodiment of the present invention has a gate line 120 intersecting a gate insulating layer 103 therebetween on a mother substrate (not shown). And a gate insulating film to form a fringe field in the pixel region formed by the data line 110, a thin film transistor (TFT) formed at each intersection thereof, and a cross structure of the gate line 120 and the data line 110. The first common electrode 107a and the slit-shaped pixel electrode 180 are formed with the 103 interposed therebetween.

The thin film transistor substrate of the present invention further includes a second common electrode 170b provided to be spaced apart from the pixel electrode 180 by a predetermined distance.

The first and second common electrodes 170a and 170b are electrically connected to the common wiring.

The gate electrode 101 is formed on the mother substrate (not shown) in the region I-I 'where the thin film transistor is located, and the gate insulating layer 103 is formed on the gate electrode 101.

The semiconductor layer 130 is disposed on the gate insulating layer 103 in a region corresponding to the gate electrode 101. The semiconductor layer 130 may include an active layer 131 and an ohmic contact layer 132.

Source / drain electrodes 140 and 150 are formed on the semiconductor layer 130. The passivation layer 160 is formed on the source / drain electrodes 140 and 150.

The protective layer 160 may include a contact hole (not shown) to expose the drain electrode 150, and the pixel electrode electrically connected to the drain electrode 150 through the contact hole on the protective layer 160. 180) is formed.

A flat common first electrode 170a is formed on the gate insulating layer 103 on the mother substrate of the pixel region II-II ', and the passivation layer 160 is formed on the first common electrode 170a. ) Is formed.

The slit pixel electrode 180 corresponding to the first common electrode 170a is formed on the passivation layer 160.

The data line 110 formed on both sides of the first common electrode 170a is provided on the semiconductor layer 130 formed on the gate insulating layer 103.

The second common electrode 170b is formed on the data line 110 with the protective layer 160 interposed therebetween.

The second common electrode 170b is provided to arrange liquid crystals around the data line 110 by a lateral electric field with the pixel electrode 180 positioned at the outermost portion of the pixel.

The second common electrode 170b partially overlaps the data line 110 and is spaced apart from the pixel electrode 180 by a predetermined distance. The second common electrode 170b is formed on the same plane as the pixel electrode 180 and may be made of the same material.

In the liquid crystal display according to the exemplary embodiment described above, the second common electrode 170b is formed to partially overlap the data line 110, so that the pixel electrode positioned at the outermost part of the pixel among the pixel electrodes 180 ( The decrease in luminance may be improved by arranging liquid crystals around the data line 110 by the transverse electric field of the 180 and the second common electrode 170b.

In addition, the present invention improves the luminance degradation around the data line 110, thereby minimizing the area of the black matrix, thereby increasing the aperture ratio.

3A to 3F illustrate a manufacturing process of a thin film transistor substrate of a liquid crystal display according to another exemplary embodiment of the present invention.

Referring to FIG. 3A, a first conductive material is formed on a mother substrate (not shown) by a deposition method such as sputtering, and a gate electrode 101 is formed by a photolithography process and an etching process using a mask.

The gate electrode 101 may be at least any one of Al, Mo, Cu, MoW, MoTa, MoNb, Cr, W, and AlNb.

The gate insulating film 103 is formed over the entire surface of the mother substrate including the gate electrode 101.

Here, the gate insulating film 103 may be any one of a silicon oxide film, a silicon nitride film, or a laminated film thereof formed through any one of chemical vapor deposition and sputtering.

Referring to FIG. 3B, the first common electrode 170a having a flat shape is formed on the gate insulating layer 103 of the pixel region.

The first common electrode 170a may be formed by a photolithography process and an etching process using a mask.

The first common electrode 170a may be formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

Referring to FIG. 3C, a source / drain electrode 140 is disposed on both ends of the semiconductor layer 130 and the semiconductor layer 130 on the gate insulating layer 103 corresponding to the gate electrode 101. , 150). At the same time, a data line 110 is formed on the gate insulating layer 103 to cross the gate line to define a pixel area.

The semiconductor layer 130 and the source / drain electrodes 140 and 150 may be simultaneously formed using a halftone mask or a diffraction mask. That is, after the amorphous silicon layer, the amorphous silicon layer of the impurity, and the second conductive material are sequentially formed on the gate insulating layer 103, the photosensitive film pattern is formed through the exposure and development processes through the halftone mask or the diffraction mask. Form. Thereafter, the second conductive material and the amorphous silicon layer are patterned according to the photosensitive film pattern to form the source / drain electrodes 140 and 150 and the active layer 131. After the ashing process is performed on the photosensitive film pattern, the amorphous silicon layer of the impurity is etched to form an ohmic contact layer 132, and then the photosensitive film pattern is removed.

Therefore, the semiconductor layer 130 and the source / drain electrodes 140 and 150 may be formed through one mask. In this case, the semiconductor layer 130 may be located under the data line 110.

Referring to FIG. 3D, a protective layer 160 is formed on the gate insulating layer 103 including the semiconductor layer 130, the source / drain electrodes 140 and 150, the data line 110, and the first common electrode 170a. Form.

The protective layer 160 is patterned by a photolithography process and an etching process using a mask to form a contact hole 151a exposing the drain electrode 150.

Referring to FIG. 3E, the second conductive electrode 170b and the pixel electrode 180 are formed by forming and patterning the transparent conductive film over the entire surface of the protective layer 160 including the contact hole 151a.

In more detail, a transparent conductive film such as ITO or IZO is formed on the protective layer 160 including the contact hole 151a and patterned by a photolithography process and an etching process using a mask to form the second common electrode 170b. ) And the pixel electrode 180 are formed.

The second common electrode 170b is formed to overlap at least a portion of the data line 110.

The pixel electrode 180 has a slit shape and overlaps the first common electrode 170b.

4 is a cross-sectional view of a liquid crystal display device showing liquid crystals arranged by a pixel electrode, first and second common electrodes according to the present invention.

As shown in FIG. 4, in the liquid crystal display of the present invention, the first common electrode 170a and the pixel electrode 180 are provided to form a fringe field between the thin film transistor substrate and the top plate (color filter substrate) 100. The liquid crystal is arranged by the transverse electric field in between. In addition, in the liquid crystal display of the present invention, a transverse electric field between the second common electrode 170b and the pixel electrode 180 is formed to overlap a portion of the data line 110 in the edge region of the pixel where the data line 110 is located. By this arrangement of the liquid crystal located on the data line 110 is achieved.

Accordingly, in the liquid crystal display of the present invention, the second common electrode 170b is provided to partially overlap the data line 110, whereby the pixel electrode 180 positioned at the outermost side of the pixel among the pixel electrodes 180 and the second common electrode 170b are provided. The liquid crystal of the periphery of the data line 110 may be arranged by the transverse electric field of the common electrode 170b to reduce the luminance deterioration of the periphery of the data line 110.

In addition, the present invention improves the luminance degradation around the data line 110, thereby minimizing the area of the black matrix, thereby increasing the aperture ratio.

In addition, according to the present invention, the second common electrode 170b having a shield function is partially overlapped on the data line 110 so that the image quality may be caused by electrical interference between the pixel electrode 180 and the data line 110. There is an additional effect that can improve the problem causing the degradation.

 Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

1 is a plan view illustrating a thin film transistor substrate of a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view of a thin film transistor substrate cut along lines II ′ and II ′ of FIG. 1.

4 is a cross-sectional view of a liquid crystal display device showing liquid crystals arranged by a pixel electrode, first and second common electrodes according to the present invention.

<Explanation of symbols for the main parts of the drawings>

110: data line 130: semiconductor layer

131: active layer 132: ohmic contact layer

170a: first common electrode 170b: second common electrode

180 pixel electrode

Claims (5)

Board; A gate line and a data line defining a pixel area on the substrate; A first common electrode provided in a flat shape in the pixel area of the substrate; A slit pixel electrode provided to correspond to the first common electrode with a protective layer interposed therebetween; And And a second common electrode spaced apart from the pixel electrode at a predetermined interval and overlapping a portion of the data line. The method of claim 1, And the second common electrode is formed on the same layer as the pixel electrode and made of the same material. Forming a gate electrode and a gate line on the substrate; Forming a gate insulating film on the substrate including the gate electrode; Forming a first common electrode on the gate insulating film; Forming a semiconductor layer, a source / drain electrode, and a data line on the gate insulating film; Forming a passivation layer on the gate insulating layer including the source / drain electrode, the first common electrode, and the data line; And And forming a pixel electrode on the passivation layer and connected to the drain electrode, and a second common electrode spaced apart from the pixel electrode at a predetermined interval. The method of claim 3, wherein The second common electrode of claim 2, wherein a portion of the second common electrode overlaps the data line. The method of claim 3, wherein And the second common electrode and the pixel electrode are made of the same material and formed on the same layer.

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