KR20070064164A - Liquid crystal display device - Google Patents

Abstract

An LCD(Liquid Crystal Display) is provided to improve the brightness, by forming a pixel electrode to have a plurality of opening patterns which are repetitively arranged in a first direction and a second direction. A gate line(121) is extended in a first direction. A common line(123) is extended in the first direction, and distanced from the gate line. A data line(131) is extended in a second direction across the first direction above the gate line and the common line. A common electrode(125) is formed in a pixel region(P) defined by crossing the gate line and the data line. The common electrode is electrically connected to the common line. A pixel electrode(175) is positioned above the common electrode with an insulating layer interposed therebetween. The pixel electrode has a plurality of opening patterns(176), wherein the opening patterns are repetitively arranged in the first direction and the second direction.

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY DEVICE}

1 is a plan view schematically illustrating a thin film transistor substrate for a typical fringe field switching mode liquid crystal display device.

FIG. 2 is a diagram schematically illustrating luminance according to a position of the thin film transistor substrate of FIG. 1.

3 is a plan view schematically illustrating a thin film transistor substrate for a fringe field switching mode liquid crystal display according to an exemplary embodiment of the present invention.

4A is a cross sectional view taken along the line AA ′ of FIG. 3, and FIG. 4B is a cross sectional view taken along the line BB ′ of FIG. 3.

♧ explanation of the reference numerals for the main parts of the drawing.

110 substrate 121 gate line

123: common line 125: common electrode

130: gate insulating film 131: data line

160: protective film 175: pixel electrode

176: opening pattern

The present invention relates to a flat panel display, and more particularly, to a liquid crystal display.

In general, a flat panel display (FPD) is a display device that provides a thin and flat screen, and is typically used as a liquid crystal display device (LCD), a large digital television, which is widely used as a notebook computer monitor. Plasma displays (PDPs), or organic electroluminescent displays (OELDs) used in mobile phones.

The liquid crystal display displays an image by changing an electrical signal into visual information by using a property in which light transmittance of a liquid crystal, which is an intermediate state material between a liquid and a crystal, is changed 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.

A TFT (Thin Film Transistor) liquid crystal display, which is a representative liquid crystal display, has a narrow viewing angle. In order to solve this problem, 1) a multi-domain structure, 2) Optimally Compensated birefringence (OCB) mode, 3) In Plane Switching (IPS) mode, and the like have been proposed. However, the multi-domain structure has a complicated process for 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 the liquid crystal due to 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 liquid crystal display has a structure in which a common electrode and a pixel electrode are overlapped with each other while an insulator is interposed on one substrate. The common electrode corresponds to the pixel area in a flat shape, and the pixel electrode is disposed on the common electrode in a slit shape in which a plurality of rod-shaped patterns are spaced apart from each other. As a result, since the transverse electric field is formed at intervals of several 다르게 apart from the IPS mode, the transverse electric field is strong and can be arranged by the transverse electric field up to the liquid crystal molecules on the electrode. In addition, since the 2 ITO structure, the white luminance can be increased to increase the aperture ratio.

1 is a plan view schematically illustrating a thin film transistor substrate for a typical fringe field switching mode liquid crystal display device. Referring to FIG. 1, the pixel region is defined by the intersection of the gate line 21 and the data line 31. The thin film transistor T is disposed at the intersection of the gate line 21 and the data line 31. The thin film transistor T includes a gate electrode formed as part of the gate line 21, a semiconductor layer 43 positioned on the gate electrode, a source electrode 51, and a drain electrode 53. The common line 23 is disposed in the pixel area P in the direction of the gate line 21. The edges of the common electrode 25 arranged in a flat shape in the pixel area P overlap the common line 23 and are electrically connected to each other. The pixel electrode 75 is disposed on the common electrode 25 via an insulating film (not shown). The pixel electrode 75 has a plurality of rod-shaped opening patterns 76. The pixel electrode 75 is connected to the drain electrode 53 of the thin film transistor T through the contact 75c, and the source electrode 51 opposite to the drain electrode 53 is connected to the data line 31.

FIG. 2 is a diagram schematically illustrating luminance according to a position of the thin film transistor substrate of FIG. 1. Referring to FIG. 2, the luminance is high near the boundary between the opening pattern 76 and the pixel electrode 75, but at the center of the pixel electrode 75 between the opening pattern 76 and the opening pattern 76. The brightness is low.

The present invention has been proposed in consideration of the above-mentioned situation, and a technical problem to be achieved by the present invention is to provide a high brightness liquid crystal display device.

The liquid crystal display according to the present invention for achieving the above technical problem includes a pixel electrode including a plurality of opening patterns.

In an exemplary embodiment, a liquid crystal display device includes a gate line extending in a first direction on a substrate, a common line extending in the first direction and spaced apart from the gate line, on the gate line and the common line. A data line extending in a second direction crossing the first direction, a common electrode electrically connected to the common line, the common electrode being positioned in a pixel region defined by the intersection of the gate line and the data line; A pixel electrode is disposed on the electrode via the insulating layer, and includes a plurality of opening patterns. In this case, the plurality of opening patterns are formed by repeating opening patterns having a predetermined shape in the first direction and the second direction.

In this embodiment, the common electrode may be formed of a transparent conductive film. The common electrode and the common line may be positioned on the same plane, and the common electrode may overlap the common line at an edge thereof.

In this embodiment, the plurality of opening patterns may be identical in shape.

According to this invention, the brightness | luminance of a liquid crystal display device becomes high.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art may easily implement the technical idea of the present invention. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed subject matter is thorough and complete, and that the spirit of the present invention to those skilled in the art will fully convey.

In the drawings, the thickness of a film or regions may be exaggerated for clarity. In addition, if it is mentioned that the film is on another film or substrate, it may be formed directly on the other film or substrate, or a third film may be interposed therebetween.

The same reference numerals throughout the specification represent the same components.

3 is a plan view schematically illustrating a thin film transistor substrate for a fringe field switching mode liquid crystal display according to an exemplary embodiment of the present invention. 4A is a cross sectional view taken along the line AA ′ of FIG. 3, and FIG. 4B is a cross sectional view taken along the line BB ′ of FIG. 3.

3, 4A, and 4B, a gate line 121 extending in a first direction is disposed on the substrate 110. The substrate 100 may be formed of a transparent insulating material such as glass, and the gate line 121 may be formed of a metal material having low resistance. The common line 123 extending in the same direction as the gate line 121, that is, in the first direction, is disposed. A flat electrode 125 is disposed between the gate line 121 and the common line 123. The common electrode 125 overlaps the common line 123 at the edge and is electrically connected to the common electrode 125. The common electrode 125 may be formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

The gate insulating layer 130 covers the substrate 110 on which the gate line 121, the common line 123, and the common electrode 125 are formed. The gate insulating layer 130 may be formed of silicon nitride or silicon oxide.

The semiconductor layer 143 is positioned on the gate electrode 122 formed as part of the gate line 121 via the gate insulating film 130. The semiconductor layer 143 includes a lower active layer 141 and an upper ohmic contact layer 142. The active layer 141 may be formed of amorphous silicon, and the ohmic contact layer 142 may be formed of amorphous silicon doped with n + type impurities.

The data line 131 in the second direction crossing the gate line 121 is disposed on the gate insulating layer 130. The pixel region P is defined by the intersection of the gate line 121 and the data line 131. The data line 131 may be formed of a metal material having low resistance. The source electrode 151 branched from the data line 131 and the drain electrode 153 facing the source electrode 151 are in contact with the ohmic contact layer 142 separated from each other.

The passivation layer 160 covers the substrate 110 on which the data line 131 is formed. The passivation layer 160 may be formed of silicon nitride or silicon oxide, or may be formed of an organic insulating layer. The pixel electrode 175 is disposed on the passivation layer 160 of the pixel region P. The pixel electrode 175 is electrically connected to the drain electrode 53 by the contact 175c. The pixel electrode 175 has a plurality of opening patterns 176. An opening pattern 176 having a predetermined shape (eg, quadrilateral) is repeated in the first direction and the second direction. In this case, the direction in which the opening patterns 176 are arranged may be the same as the first direction and the second direction, or may be inclined at a predetermined angle with respect to the first direction or the second direction.

Unlike the general FFS mode liquid crystal display, the liquid crystal display according to the exemplary embodiment of the present invention decreases the size of the opening pattern 176 so that the boundary between the pixel electrode 175 and the opening pattern 176 is wider. As a result, the luminance is increased.

On the other hand, in the detailed description of the present invention has been described with respect to specific embodiments, various modifications are of course possible without departing from the scope of the invention.

Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be defined not only by the claims below but also by the equivalents of the claims of the present invention.

According to the present invention described above, the luminance of the liquid crystal display device is increased.

Claims (4)

A gate line extending in a first direction on the substrate; A common line extending in the first direction and spaced apart from the gate line; A data line extending in a second direction crossing the first direction on the gate line and the common line; A common electrode positioned in the pixel area defined by the intersection of the gate line and the data line, and electrically connected to the common line; And Located on the common electrode via an insulating film, including a pixel electrode including a plurality of opening patterns, The plurality of opening patterns includes a plurality of opening patterns having a predetermined shape repeated in the first direction and the second direction. The method of claim 1, The common electrode is a liquid crystal display device comprising a transparent conductive film. The method of claim 1, The common electrode and the common line are disposed on the same plane, and the common electrode overlaps the common line at an edge thereof. The method of claim 1, The plurality of opening patterns have the same shape.

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