KR20000020859A - Liquid crystal display and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A liquid crystal display and a manufacturing method thereof are provided to improve image quality and to reduce an inferior rate by converting a high pixel defect marked with white color to off pixel defect marked with black color in the liquid crystal display. CONSTITUTION: A multiplicity of gate lines(101,102) are formed horizontally with a uniform distance on an insulation substrate, A multiplicity of data lines(21) are separated from a layer, wherein each gate line is formed, by an insulation film and are formed at a uniform distance in the vertical direction of insulation substrate. A pixel domain(30) is formed in a domain at which the data lines and the gate lines are crossed. A multiplicity of common terminals(41) are formed between the gate lines(101,102) when the gate lines(101,102) are formed. A drain electrode(D) is contacted with a gate electrode(G), a source electrode(S) and a pixel electrode(30). A thin film transistor(TFT) is formed with formation of an amorphous silicon layer(22) between the gate electrode(G) and the source and drain electrode(S,D).

Description

Liquid Crystal Display and Manufacturing Method Thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display and a method of manufacturing the same. More specifically, the high pixel defect displayed in white in the independent wiring type liquid crystal display is displayed in black. The present invention relates to a liquid crystal display device and a method of manufacturing the same.

Generally, a liquid crystal display device includes a thin film transistor substrate, a color filter substrate facing the thin film transistor substrate, and a liquid crystal material injected between the substrates, and uses an electrical optical effect of the liquid crystal material inserted therein. It is a display device.

Therefore, the operation state of each pixel is determined by outputting the corresponding driving signal and the image signal through the gate line and the data line, thereby displaying a desired image.

Therefore, many data lines and gate lines must be formed through the manufacturing process, and the lines formed because the data lines or the gate lines are not formed correctly are shorted or shorted with adjacent lines, so that each pixel Pixel defects occur where no input signal is applied.

As described above, the pixel defect does not input the correct data signal or the gate signal, thereby deteriorating the image quality.

These pixel defects include off pixel defects that are always displayed in black and high pixel defects that are always displayed in white.

In general, high pixel defects are more prominent than off pixel defects, which is a fatal defect in the image quality of the liquid crystal display.

Therefore, in the case of high pixel defects occurring vertically or horizontally adjacent to each other in the final filtering process, it is often treated as a defective product.

The cause of high pixel combining or adjacent high pixel defects varies depending on the characteristics of the line used, but the following are common.

① When the pixel is shorted up and down by pixel patterning failure,

(2) If the pixel is shorted from side to side due to poor pixel patterning,

③ When the leakage current of the thin film transistor is very large,

(4) A short circuit occurs between pixels due to residual impurities and a silicon film.

In the case of the thin-film transistor liquid crystal display, in the case of the shear gate method in which a storage capacitance is formed by overlapping the pixel electrode and the front gate line, a short circuit between the pixel electrode and the gate is performed by laser shorting to the pixel electrode. Allow the gate voltage to be applied.

In general, there are a low voltage driving method and a high voltage driving method shown in FIG. 1B as shown in FIG. 1A.

In the low voltage driving method, a gate voltage of about -15 to about 15 is applied, and a data voltage DV of several volts is applied in a pulse state. At this time, the common voltage CV is applied in a pulse state slightly larger than the data voltage DV and opposite to the waveform of the data voltage DV.

In the high voltage driving method, a large gate voltage GV of about -15 to 15 is applied, and a data voltage DV having a value larger than the data voltage DV applied in the low voltage driving method is applied in a pulse state. However, at this time, the common voltage CV is fixed to a constant value.

However, as shown in FIGS. 1A and 1B, since the gate voltage GV always has a high voltage difference from the common voltage CV, when the gate voltage GV is applied to the pixel, the common of the pixel electrode and the upper substrate is common. A high voltage is always applied between the electrodes (H) and always remains black as the liquid crystals are arranged side by side in the electric field.

As a result, the gate voltage remains off for most of the time, so that even when a high pixel defect occurs, it is switched to an off pixel defect.

However, in an independent wiring method (storage-on-common method), independent common lines and pixel electrodes are used to form a storage capacitor.

A wiring structure of a liquid crystal display substrate using a general independent wiring method will be described with reference to FIGS. 2A and 2B.

As shown in FIG. 2A, a plurality of gate lines 11 are formed on the insulating substrate (not shown) at a predetermined interval in the horizontal direction, and each gate line 11 is separated into an insulating layer and an insulating layer, and is insulated. A plurality of data lines 21 are formed long at regular intervals in the longitudinal direction of the substrate.

Therefore, the pixel electrode 30 is formed in the region where the data line 11 and the gate line 21 cross each other.

In addition, when the gate line 11 is formed, a plurality of common terminals 41 are formed simultaneously with the gate line 11 with the same material between the gate lines 11.

And a gate electrode G which is a branch of the gate line 11, a source electrode S which is a branch of the data line 21, and a drain electrode D which is in contact with the pixel electrode 30. An amorphous silicon layer 22, which is an insulating layer, is formed between the electrode G and the source and drain electrodes S and D to form one thin film transistor TFT.

FIG. 2B is a cross-sectional view displayed when the AA ′ portion of FIG. 2A is cut. FIG.

As shown in FIG. 2B, a gate insulating film 12 is formed on the gate line 11, and a protective film 13 is formed on the gate insulating film 12. In addition, the pixel electrode 30 is formed on one side of the passivation layer 13, and the pixel electrode 30 does not overlap the gate line 11.

In the independent wiring type liquid crystal display device having such a wiring structure, an independent common terminal 41 and a pixel electrode 30 are used to form a storage capacitor.

Therefore, when the pixel electrode 30 is shorted with the common terminal 41 and an off voltage is applied to the common terminal 41, high pixel defects appear, which causes deterioration of image quality of the liquid crystal display and an increase in the defective rate. It became.

Therefore, a technical problem to be achieved by the present invention is to convert high pixel defects to off pixel defects during the manufacturing process of the liquid crystal display device, thereby reducing deterioration of image quality and reducing defective rate.

1A illustrates a low voltage driving method among data driving methods,

1B and a high voltage driving method of the data driving method are illustrated.

FIG. 2A illustrates a wiring structure of a liquid crystal display substrate of an independent wiring method.

FIG. 2B is a cross-sectional view displayed when the AA ′ portion of FIG. 2A is cut;

3 illustrates a wiring structure of a liquid crystal display substrate of an independent wiring method according to a first embodiment of the present invention.

FIG. 4 illustrates a wiring structure of an independent wiring type liquid crystal display substrate according to a second exemplary embodiment of the present invention.

FIG. 5 is a cross-sectional view of the cut line BB ′ of FIGS. 3 and 4.

In order to solve this problem, in the present invention, an overlapping region is formed between the gate line and the pixel electrode to shorten the overlapping region of the gate line and the pixel electrode when a high pixel defect occurs.

Preferably, the overlapping region is formed by extending the gate line toward the pixel electrode.

It is preferable that the area of the overlapping area is 1 × 1 (µm ² ).

Then, with reference to the accompanying drawings with respect to the liquid crystal display device according to an embodiment of the present invention and a method of manufacturing the most preferred embodiment that can be easily carried out by those skilled in the art to which the present invention belongs An example will be described in detail with reference to the accompanying drawings. Parts having the same structure as those of the prior art and performing the same operation are given the same symbols as those of the prior art.

As shown in FIG. 3, the wiring structure of the liquid crystal display substrate according to the first embodiment of the present invention has a plurality of gate lines 101, 102, .. ) Is formed, the gate lines 101, 102,... Are separated into a layer and an insulating film, and a plurality of data lines 21 are formed long at a predetermined interval in the longitudinal direction of the insulating substrate.

As a result, the pixel region 30 is formed in the region where the data lines 101, 102,... And the gate line 21 intersect.

In addition, when the gate lines 101, 102,... Are formed, a plurality of common terminals 41 are formed simultaneously with the gate lines 101, 102, .. with the same material between the gate lines 101, 102,.

A gate electrode G which is a branch of the gate line 101, a source electrode S which is a branch of the data line 21, and a drain electrode D which is in contact with the pixel electrode 30 are formed. An amorphous silicon layer 22, which is an insulating layer, is formed between the electrode G and the source and drain electrodes S and D to form one thin film transistor TFT. One thin film transistor TFT is formed for each pixel.

As such, when the nth pixel electrode 30 is formed between the nth gate line 101 and the n + 1th gate line 102, the branch 1021 of the n + 1th gate line 102 is n. The second pixel electrode 30 is formed to have a region overlapping with the first pixel electrode 30.

4 shows a wiring structure of a liquid crystal display substrate according to a second embodiment of the present invention. The wiring structure shown in FIG. 4 has the same structure as shown in FIG.

However, the branch 10011 of the n−1 th gate line 1001 is formed to have a region overlapping with the n th pixel electrode 30.

FIG. 5 is a cross-sectional view of the branches 1021 and 10011 of the n-th or n-th gate lines 101 and 1001, and is a cross-sectional view displayed when the section BB 'of FIGS. 3 and 4 is cut.

As shown in FIG. 5, a gate insulating film 12 is formed on the gate lines 102 and 1001, and a protective film 13 is formed on the gate insulating film 12. In addition, the pixel electrode 30 is formed on one side of the protective film 13. At this time, the pixel electrode 30 and the gate lines 102 and 1001 overlap certain regions as shown in FIG. 5.

As shown in the structure according to the first and second embodiments of the present invention, the portion where the pixel electrode 30 and the gate lines 102 and 1001 overlap with each other is formed by the corresponding gate lines 102 and 1001. The pixel electrode 30 may be extended to the corresponding gate lines 102 and 1001.

In addition, the region overlapping the pixel electrode 30, so the result of increasing the parasitic capacitance, which overlap area is preferably at least the area of extent of the laser repairable, be designed as at least about 1 × 1 (㎛ ²⁾ desirable.

The operation of the first and second embodiments of the present invention having such a wiring structure is as follows.

When the gate signal is sequentially applied, the on voltage is applied to the gate electrode G of each thin film transistor TFT through the gate lines 101, 1001, 102, and 1002. Then, when the data signal is applied through the data line 21, the pixel electrode 30 operates according to the difference between the voltage applied to the drain electrode D and the source electrode S through each data line 21. Work with brightness

However, a short occurs between the data line 41 and the pixel electrode 30 during the manufacturing process of the liquid crystal display substrate, so that the pixel electrode 30 generates a high pixel defect that is always displayed in white.

Therefore, when a high pixel defect occurs in the liquid crystal display substrate, the branches 1021 and 10011 of the gate lines 102 and 1001 formed to overlap the pixel electrode 30 may be formed using a laser or the like. Connect and disconnect the other shorted part.

Therefore, when the gate signal is applied to the gate lines 102 and 1001 connected to the pixel electrode 30, the pixel electrode 30 shows a high pixel defect that is displayed in white, but no other gate signal is applied. During the transition to the off-pixel defect state displayed in black.

Therefore, high pixel defects that are easily noticeable and have a lot of adverse effects on image quality are converted to relatively less noticeable off pixel defects.

The effects of the present invention operating as described above can convert the high pixel defects that increase the defective rate of the liquid crystal display substrate into the off pixel defects, thereby improving the image quality of the liquid crystal display device and reducing the defective rate.

Claims (5)

A liquid crystal display device comprising a plurality of gate lines, a plurality of data lines, a plurality of pixel electrodes formed at portions where the plurality of gate lines and data lines cross each other, and a plurality of common terminals. And a region in which each pixel electrode overlaps with a gate line formed next to or before the gate line of the plurality of pixel electrodes. The method of claim 1, The overlapping region is formed by extending a gate line toward a pixel electrode. The method according to claim 1 or 2, The area of the overlapping area is 1 × 1 (μm ² ). In the manufacturing method of a liquid crystal display device, And forming a region in which each pixel electrode overlaps with a gate line formed next to or before the gate line corresponding to the pixel electrode. The method of claim 4, wherein The overlapping region is formed by extending a gate line toward a pixel electrode.