KR100711216B1 - Liquid crystal display - Google Patents

Abstract

The present invention relates to a liquid crystal display device capable of preventing ripples, mura, etc. generated when the electric field and charge values applied to the liquid crystal are changed by the cell gap and the surface potential when pressed. A gate line and a data line are arranged to cross each other, and a thin film transistor is provided at an intersection between the lines, and an array substrate having pixel electrodes arranged in a pixel defined by the lines, and maintains a constant cell gap with the array substrate. A color filter substrate having a common electrode disposed in a region to be formed, a black matrix disposed at a region corresponding to the pixel boundary portion on a common electrode surface of the color filter substrate, a color filter disposed at a region corresponding to the pixel, and In the liquid crystal display device provided with the liquid crystal interposed between the array substrate and the color filter substrate, the present invention is disposed on the color filter substrate and grounded to block the fluctuation of the electric field applied to the liquid crystal due to the change in the cell gap between the two substrates An electrode.

Description

Liquid Crystal Display {LIQUID CRYSTAL DISPLAY}

1 is a layout diagram of a liquid crystal display device according to the prior art.

2 is a cross-sectional view of a liquid crystal display device according to the prior art.

3 is a cross-sectional view of a liquid crystal display device according to an embodiment of the present invention.

4 is a first embodiment of a first ground electrode according to the present invention;

5 is a second embodiment of a first ground electrode according to the present invention;

6 is a third embodiment of a first ground electrode according to the present invention;

7 is a fourth embodiment of a first ground electrode according to the present invention;

8 is a cross-sectional view of a liquid crystal display according to another exemplary embodiment of the present invention.

The present invention relates to a liquid crystal display, and more particularly, a ripple generated by transferring the changed potential level into a cell as the electric field and charge value applied to the liquid crystal are changed by a cell gap and a surface potential when pressed. The present invention relates to a liquid crystal display device capable of preventing mura and the like.

In addition to the development of information infrastructure, TV display devices or OA PC monitors, which are video and audio information terminals, continue to be developed. In particular, the application of liquid crystal display devices to small and medium-sized TVs and OA PC monitors is expected to expand in the future from the social request for space and power saving. In order for these liquid crystal display devices to meet the market demand, low driving voltage, high contrast ratio, and high speed response are required. In order to realize these characteristics, a display mode using a liquid crystal layer having uniformly aligned liquid crystal molecules is preferable, and the TN mode which is most widely used now corresponds to this.

1 is a layout for schematically illustrating a TN mode liquid crystal display device according to the prior art.

2 is a cross-sectional view of a liquid crystal display device according to the prior art, wherein the array substrate 1 shows a cross section taken along line AB of FIG.

As shown in FIG. 1, a TN mode liquid crystal display according to the related art includes an array substrate 1 including a thin film transistor a and a pixel electrode 4, a common electrode 12, a black matrix ( 14) and the color filter substrate 10 including the color filter 16 and the like are bonded to each other under a liquid crystal layer (not shown).

In detail, as shown in FIG. 2, several gate lines 2 and data lines 3 are arranged on the array substrate 1, and thin film transistors a are provided at the intersections of the lines. The pixel electrode 4 is disposed in the pixel defined by the lines.

On the color filter substrate 10, a black matrix 14 is formed in a region corresponding to a pixel boundary, and color filters 16 of red, green, and blue are formed in each portion corresponding to a pixel, and the black matrix ( The common electrode 12 is formed on the entire region including the 14 and the color filter 16.

However, in the related art, since the common electrode covers the entire surface of the color filter substrate, when the cell gap is changed, the capacitor does not accumulate for a long time because the capacitor of the liquid crystal that moves the liquid crystal is larger than that of the array substrate.

Accordingly, the transmittance is controlled by the holding characteristics and the cell gap change, thereby causing problems such as ripping and mura in the liquid crystal display.

Accordingly, the present invention has been made to solve the above problems, by suppressing the fluctuation of the electric field and charge value applied to the liquid crystal according to the change of the cell gap and the surface potential when pressed, it is possible to reduce the occurrence of ripple, mura, etc. It is an object of the present invention to provide a liquid crystal display device.

In order to achieve the above object, an array substrate having a gate line and a data line intersected and a thin film transistor provided at an intersection portion between the lines and a pixel electrode arranged in a pixel defined by the lines, A color filter substrate having a cell gap and having a common electrode disposed in a region corresponding to a pixel, a black matrix disposed in a region corresponding to the pixel boundary portion on a common electrode surface of the color filter substrate, and a black matrix disposed in a region corresponding to the pixel In the liquid crystal display device having a color filter and a liquid crystal interposed between the resultant array substrate and the color filter substrate, the present invention is disposed on a color filter substrate and applied to the liquid crystal according to a cell gap change between the two substrates. Characterized in that it comprises a ground electrode to block the fluctuation of the.

In this case, the ground electrode is disposed between any one of the front surface of the black matrix including the color filter and between the color filter substrate and the common electrode.

In addition, an insulating film is added on the color filter substrate including the ground electrode, and a low dielectric film having a dielectric constant? In a range of 1.8 <ε≤2 is used as the insulating film.

In addition, the insulating film uses any one of BCB, acrylic, siloxane, and airgel as a material, and is formed to a thickness of 0.5 μm or more.

A conductive polarizer is added on the color filter substrate having the black matrix and the color filter.

On the other hand, the ground electrode is formed in a portion corresponding to any one of the pixel region, one dot color filter, the gate line and the data line, the stripe shape along the direction of any one of the gate line and the data line of the array substrate Is arranged. The stripe shape is any one of a single structure and a reticulated net structure.

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

3 is a cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

As shown in FIG. 3, the liquid crystal display according to the exemplary embodiment of the present invention includes an array substrate 20 including a thin film transistor (b) and a pixel electrode 26, a common electrode 32, and black. The color filter substrate 30 including the matrix 38, the color filter 40, and the like is bonded to each other under the interposition of the liquid crystal layer (not shown).

In detail, a plurality of gate lines 24 and data lines 22 are intersected on the array substrate 20, and thin film transistors b are disposed at the intersections of the lines, and the pixels defined by the lines are arranged. The pixel electrode 26 is disposed inside.

In addition, the ground electrode 32 and the insulating film 34 are sequentially arranged on the color filter substrate 30, and the black matrix (black matrix) is formed on the area corresponding to the pixel boundary on the color filter substrate 30 provided with the insulating film 34. 38 is formed, and color filters 40 of red, green, and blue are formed in respective portions corresponding to the pixels. In this case, the common electrode 36 is arranged in the pixel portion exposed by the black matrix 38 between the insulating layer 34 and the color filter 40.

Here, the ground electrode 32 serves to block the variation of the electric field applied to the liquid crystal according to the change in the cell gap between the array substrate 20 and the color filter substrate 30, and the material is ITO (Indium Tin Oxide) ).

Although not shown in the drawings, a liquid crystal layer is interposed between the color filter substrate and the array substrate of the above structure.

4, 5, 6 and 7 show the first, second, third and fourth embodiments of the ground electrode according to the present invention, respectively. Here, the dotted line portion becomes the ground electrode.

In detail, FIG. 4 illustrates a ground electrode arranged in a stripe type in a single structure along a data line or gate line direction as a first embodiment of the ground electrode according to the present invention. (See dotted line)

FIG. 5 is a view showing that the ground electrodes (dotted portions) are arranged in a mesh shape combining stripe shapes as a second embodiment of the ground electrode according to the present invention.

6 is a third embodiment of the ground electrode according to the present invention, in which the ground electrodes (dotted portions) are arranged in a stripe shape along the gate line direction, and the stripe shape is divided into two.

7 is a fourth embodiment of the ground electrode according to the present invention in which the ground electrodes (dotted portions) are arranged in a stripe shape along the data line direction, and the stripe form is divided into two.

The ground electrode 32 may be formed at a portion corresponding to one dot of the color filter, the pixel region, the gate line, or the data line.

The ground electrodes 32 may be arranged in a symmetrical structure with each other.

In addition, the insulating film 34 is a low dielectric film having a dielectric constant? In a range of 1.8 <ε <2.5, preferably 1.8 <ε≤2, and includes BCB, acryl, siloxane, Any one of an aerogel is used. In this case, the reason why the material having the low dielectric constant is used as the insulating film 34 is to allow the material to hold the potential / charge applied to the pixel for a long time, thereby improving the characteristics of the liquid crystal display device. .

On the other hand, the insulating film 34 is formed to a thickness of 0.5㎛ or more, the thicker the thickness of the insulating film can reduce the phenomenon caused by the potential variation.

8 is a cross-sectional view of a TN mode liquid crystal display according to another exemplary embodiment of the present invention.

In another embodiment of the present invention, unlike the embodiment of the present invention in which the ground electrode 42 is disposed between the color filter substrate and the common electrode, the black matrix 38 and the color filter (on the upper substrate 30) ( 40). In this case, indium tin oxide (ITO) is used as a material of the ground electrode 42.

Alternatively, although not shown in the drawing, the conductive polarizer may be arranged so as to cover the black matrix and the color filter structure on the upper substrate instead of the ground electrode.

According to the present invention, by placing the ground electrode on the color filter substrate, the ground electrode serves to protect the potential level changed by the change of the cell gap from being transferred into the cell.

As described above, the present invention arranges the ground electrode in the form of a stripe of the common electrode along the gate line or data line direction on the color filter substrate, thereby reducing signal delay due to coupling between the common electrode and the gate line or data line. It is possible to obtain a clear picture quality and to improve signal transmission by not transmitting dynamic vibrations and electrostatic potential changes due to pressing to neighboring pixels, thereby achieving low power consumption, high aperture ratio, and high transmittance.

In addition, in the present invention, since the potential variation in the cell is reduced and the total transmittance difference is reduced, phenomena such as ripple or muura do not occur.                     

On the other hand, the present invention by using any one of the BCB, acrylic, siloxane and airgel as the insulating film, it is possible to reduce the external potential and internal potential changes without increasing the driving voltage by reducing the parasitic capacitance with the common electrode through the insulating film. .

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

Claims (9)

An array substrate having a gate line and a data line intersecting with each other, a thin film transistor disposed at an intersection between the lines, and a pixel electrode disposed in a pixel defined by the lines; A ground electrode disposed on an inner surface of the transparent substrate facing the array substrate, an insulating film disposed to face the ground electrode, and a common electrode disposed on the insulating film so as to face the ground electrode and disposed in an area corresponding to the pixel A color filter substrate including a black matrix disposed between the pixels and a color filter disposed in an area corresponding to the pixel; And And a liquid crystal interposed between the array substrate and the color filter substrate. The method of claim 1, wherein the ground electrode And a liquid crystal display device disposed between any one of the color filter substrate and the common electrode and a front surface of the black matrix including the color filter. delete The liquid crystal display device according to claim 1, wherein the insulating film is a low dielectric film having a dielectric constant? In a range of 1.8 < The liquid crystal display device of claim 1, wherein the insulating film includes any one selected from the group consisting of BCB, acrylic, siloxane, and aerogel. The liquid crystal display device according to claim 1, wherein the insulating film has a thickness of 0.5 µm or more. The liquid crystal display of claim 1, wherein the ground electrode is formed at a portion corresponding to one of a dot filter, a gate line, and a data line in a region corresponding to the pixel. The liquid crystal display of claim 1, wherein the ground electrodes are arranged in a stripe shape along one of a gate line and a data line of the array substrate. The liquid crystal display device according to claim 8, wherein the stripe shape is any one of a single structure and a water structure in which a plurality thereof are combined.

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