KR100877537B1 - Method of repair for Bad Pixel of Liquid Crystal Panel - Google Patents

Abstract

In the present invention, the first surface of the first substrate and the second surface of the second substrate are disposed to face each other, and an array element is formed on the first surface corresponding to the plurality of pixels defined in the first substrate. In the liquid crystal panel in which the first and second substrates are bonded together with a liquid crystal layer interposed between the first and second surfaces, detecting a defective pixel by inspecting a screen of the liquid crystal panel; A dark ignition pattern made of an opaque material corresponding to the defective pixel on a third surface of the first substrate that is opposite to the first surface or a fourth surface of the second substrate that is opposite to the second surface It provides a method for repairing defective pixels of the liquid crystal panel comprising the step of forming a.

Description

Method of repairing bad pixel of liquid crystal panel {Method of repair for Bad Pixel of Liquid Crystal Panel}

1 is a three-dimensional view of a portion of a general liquid crystal display device.

2 is a view showing a bad cell repair process of a conventional liquid crystal panel.

Figure 3 is a schematic view showing a bad cell repair process of the liquid crystal panel according to the present invention.

4 is a cross-sectional view of a liquid crystal panel including a dark ignition pattern according to the first embodiment of the present invention.

5 is a cross-sectional view of a liquid crystal panel including a dark ignition pattern according to a second embodiment of the present invention.

<Description of Symbols for Major Parts of Drawings>

210: first substrate 230: second substrate

232: black matrix 234: color filter

236: color filter layer 238: overcoat layer

240 common electrode 250 liquid crystal layer                 

IV: array device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a defective cell repair method of a liquid crystal display device.

Recently, liquid crystal displays have been spotlighted as next generation advanced display devices having low power consumption, good portability, technology-intensive, and high added value.

In general, in order to use a liquid crystal for a display, a liquid crystal cell must be manufactured.

The liquid crystal cell has a structure in which a liquid crystal is filled between two glass substrates or a transparent plastic substrate. A transparent electrode (common electrode, pixel electrode) is formed on the substrate so that voltage can be applied to the liquid crystal. The transparent electrode serves to control on / off by applying a voltage to the liquid crystal.

That is, the light transmission amount of the liquid crystal display device is controlled by the voltage applied to the transparent electrode, and displays characters / images by the optical shutter effect.

Among such liquid crystal display devices, an active matrix liquid crystal display device having a switching element capable of controlling voltage on / off for each pixel is attracting the most attention due to its excellent resolution and video performance.

FIG. 1 is a three-dimensional view of a partial area of a general liquid crystal display, and is shown centering on an active area defined as an area in which a liquid crystal is driven.

As shown in the figure, the upper and lower substrates 10 and 30 face each other with a predetermined distance therebetween, and the liquid crystal layer 50 is interposed between the upper and lower substrates 10 and 30.

A plurality of gates and data lines 32 and 34 cross each other on the lower substrate 30, and a thin film transistor T is formed at a point where the gates and data lines 32 and 34 cross each other. A pixel electrode 46 connected to the thin film transistor T is formed in the pixel area P defined as an area where the gate and the data lines 32 and 34 intersect.

Although not shown in the drawing, the thin film transistor T includes a gate electrode to which a gate voltage is applied, a source and drain electrode to which a data voltage is applied, and a channel for controlling voltage on / off by a difference between the gate voltage and the data voltage ( ch; channel).

The color filter layer 12 and the common electrode 16 are sequentially formed below the upper substrate 10.

Although not shown in detail in the drawing, the color filter layer 12 is composed of a color filter for transmitting only light of a specific wavelength band and a black matrix positioned at a boundary of the color filter to block light on an area where the arrangement of liquid crystals is not controlled.

In addition, upper and lower polarizers 52 and 54 are disposed on each outer surface of the upper and lower substrates 10 and 30 to transmit only light parallel to the polarization axis, and a backlight, which is a separate light source, is provided below the lower polarizer 54. back light) is placed.

The liquid crystal display device uses a substrate that has undergone an array substrate manufacturing process for forming a switching element and a pixel electrode and a color filter substrate manufacturing process for forming a color filter and a common electrode, and a liquid crystal cell process that interposes liquid crystal between the two substrates. Completed through

The liquid crystal cell process may be characterized in that the process is relatively little compared to the array process or the color filter process. The whole process can be largely divided into an alignment layer forming process for forming the liquid crystal molecules, a cell gap forming process, a cell cutting process, and a liquid crystal injection process. After attaching the polarizing plates to the outside of the liquid crystal panel, the liquid crystal display device is completed by connecting the driving circuits.

2 is a view showing a bad cell repair process of a conventional liquid crystal panel.

As illustrated, a plurality of gates and data lines 62 and 74 are formed in the liquid crystal panel 90 in a direction crossing each other, and a thin film transistor T at a point where the gates and data lines 62 and 74 cross. ) Is formed, and the pixel electrode 76 is formed for each pixel in connection with the thin film transistor T.

In this case, a region where the gate line 62 and the pixel electrode 76 overlap with each other forms a storage capacitor C _ST in a state where an insulator (not shown) is interposed therebetween.

In the inspection process of the liquid crystal panel 90, a test pattern is floated on the screen of the liquid crystal panel 90, and the presence or absence of a bad pixel is detected to perform a repair operation when a bad pixel is found.

The defects of the liquid crystal panel 90 include color defects for each pixel cell, dot defects such as bright spots (cells that are always on), dark spots (cells that are always off), and short circuits between the data lines 74 adjacent to the gate lines 62. (Line Defect) occurs due to (short). Such defects are apparent in the eyes of the operator when the test patterns are floated on the completed liquid crystal panel 90, and the operator detects the position of the defective pixel and repairs the portion thereafter.

In the drawing, when the black pattern is floated on the screen, a process of darkening the defective cell (II), which appears as a bright point for the reason of short or signal failure, for dark repair for example.

Conventionally, the pixel electrode 76 of the defective cell (II) is single-contacted with the gate wiring 62 by laser, and a part of the pixel electrode 76 is cut and applied to the gate wiring 62 by a repair process for the bright point. The method of darkening the defective cell (II) by using the gate voltage to remain in the defective cell (II) has been mainly used.

However, in the single-contact process using the laser, there is a problem that the foreign matter white point defect is generated by locally agglomerating the foreign matter crushed during the process does not spread evenly.

When the pixel electrode 76 is not cut well in the cutting process of the pixel electrode 76 made of a material such as the pixel electrode 76 and the gate wiring 62 and the ITO, the gate and data wiring There is a problem in that the line defects are generated by shorting the 62 and 74.

In order to solve this problem, the present invention is to provide a defective cell repair process of the liquid crystal panel that can easily darken and reduce the peripheral blur due to the repair or secondary defects.

In order to achieve the above object, in the present invention, the first surface of the first substrate and the second surface of the second substrate are disposed to face each other, and correspond to the plurality of pixels defined in the first substrate. In the liquid crystal panel in which the array element is formed, and the first and second substrates are bonded while the liquid crystal layer is interposed between the first and second surfaces, the screen of the liquid crystal panel is inspected to detect defective pixels. Detecting; A dark ignition pattern made of an opaque material corresponding to the defective pixel on a third surface of the first substrate that is opposite to the first surface or a fourth surface of the second substrate that is opposite to the second surface It provides a defective pixel repair method of a liquid crystal panel comprising the step of forming a.

The dark ignition pattern is formed by using a gas chromium carbonate through a laser irradiation in a vacuum state by the air curtain.
The second substrate is characterized in that the color filter substrate.

And, the thickness of the dark ignition pattern is characterized in that 1500 ~ 2000 kPa.

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

3 is a view showing a bad cell repair process of the liquid crystal panel according to the present invention.

As illustrated, a plurality of gate lines 162 are formed in the liquid crystal panel 190 in a first direction, and a plurality of data lines 174 are formed in a second direction crossing the first direction. The region where the gates and the data lines 162 and 174 cross each other is defined as a pixel area P, and the thin film transistor T is positioned at the point where the gates and the data lines 162 and 174 cross each pixel area P. FIG. ) Is positioned and connected to the thin film transistor T to form the pixel electrode 176.

In addition, the pixel electrode 176 that crosses the gate line 162 forms a storage capacitor C _ST in a state where an insulator (not shown) is interposed therebetween.

However, in the present invention, a common method using the overlapping region of the common method capacitor electrode and the pixel electrode as the storage capacitor may be applied.

When bright spots are generated by the defective cells III on the liquid crystal panel 190 having the above structure, a dark ignition pattern 200 serving as a repair function is formed on the region covering the defective cells III. .

In particular, the dark ignition pattern 200 is formed by using a chromium carbonate (Cr carbonate) as a metal complex in a partial vacuum state by a separate air curtain (air curtain), the metal complex in a gas state, the substrate through a laser A chemical vapor deposition (CVD) device (hereinafter, abbreviated to NEC-CVD device) of NEC (Nippon Electric Company) for forming a chromium layer on the surface is used.

According to the NEC-CVD apparatus, it is possible to easily form a fine pattern by adjusting the slit size of the laser device.

<Example 1>

Example 1 is an example in which a dark ignition pattern is formed in a region covering a defective cell on the outer surface of the upper substrate.

FIG. 4 is a cross-sectional view of a liquid crystal panel including a dark ignition pattern according to a first embodiment of the present invention. In order to show the arrangement structure of the dark ignition pattern, the array substrate structure is schematically illustrated.

As illustrated, the first and second substrates 210 and 230 are disposed to face each other, and the first and second substrates 210 and 230 have a liquid crystal layer 250 interposed therebetween. An array element IV is formed on the upper portion of the 210, and a black matrix 232 is formed at each lower boundary of each of the second substrates 230 and overlaps the black matrix 232 at a predetermined interval. The color filters 234 are formed by sequentially arranging the green, blue, and blue color filters 234a, 234b, and 234c, and the black matrix 232 and the color filter 234 form a color filter layer 236.

An overcoat layer 238 and a common electrode 240 are sequentially formed below the color filter layer 236.                     

Although not shown in detail in the drawings, the array element IV refers to an array element including a gate and a data line, a thin film transistor, and a pixel electrode.

For example, when the pixel of the green color filter 234b is a defective cell, a dark ignition pattern 260 is formed in an area covering the green color filter 234b on the outer surface of the second substrate 230, which is the upper substrate. .

The dark ignition pattern 260 is characterized in that the chromium material formed by the NEC-CVD method described above

<Example 2>

Embodiment 2 is an embodiment in which a dark ignition pattern is formed in a region covering a defective cell on the outer surface of the lower substrate.

FIG. 5 is a cross-sectional view of a liquid crystal panel including a dark ignition pattern according to a second embodiment of the present invention. A case in which the green color filter pixel is a defective cell will be described. Omit.

As shown, in the present embodiment, the dark ignition pattern 360 is positioned on the outer surface of the first substrate 210 at a position corresponding to the green color filter 234b on the outer surface of the second substrate 230. It features.

The dark ignition pattern 360 is formed in the same manner as the dark ignition pattern 260 of FIG. 4 according to the first embodiment.

In addition, the dark ignition pattern according to the present invention has a thickness range of 1500 to 2000 mW, so that polarizers and gaps attached to both outer surfaces of the first and second substrates do not occur.

However, the present invention is not limited to the above embodiments, and various modifications may be made without departing from the spirit of the present invention.

As described above, according to the defective cell repair pattern of the liquid crystal panel according to the present invention, it is easy to darken the defective cell serving as the bright point, and it is possible to remove secondary defective elements such as a foreign material white point or a gate wiring short. A reliable repair process can be provided.

Claims (4)

The first surface of the first substrate and the second surface of the second substrate are disposed to face each other, and an array element is formed on the first surface corresponding to the plurality of pixels defined in the first substrate. In a liquid crystal panel in which the first and second substrates are bonded together with a liquid crystal layer interposed between a surface and a second surface, Inspecting the screen of the liquid crystal panel to detect defective pixels; A dark ignition pattern made of an opaque material corresponding to the defective pixel on a third surface of the first substrate that is opposite to the first surface or a fourth surface of the second substrate that is opposite to the second surface Forming a; Defective pixel repair method of a liquid crystal panel comprising a. The method of claim 1, The dark ignition pattern is a defective pixel repair method of a liquid crystal panel, characterized in that formed by using a gas chromium carbonate through a laser irradiation in a vacuum state by the air curtain. The method of claim 1, And the second substrate is a color filter substrate. The method of claim 1, The thickness of the dark ignition pattern is a defective pixel repair method of the liquid crystal panel 1500 ~ 2000 kPa.

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