KR101174287B1 - Liquid crystal display panel and repairing method thereof - Google Patents

Abstract

The present invention relates to a liquid crystal display panel and a repair method thereof, which can improve yield by darkening a bright point to minimize a defective rate.

The liquid crystal display panel of the present invention comprises a substrate; Holes formed at positions corresponding to regions in which bright spots appear on the substrate; And an opaque material filled in the hole.

Description

Liquid crystal display panel and its repair method {LIQUID CRYSTAL DISPLAY PANEL AND REPAIRING METHOD THEREOF}

1 is a cross-sectional view showing a conventional liquid crystal display panel.

2 is a cross-sectional view for explaining the misalignment caused by foreign matter inserted in the process.

3 is a view showing a bright spot appearing when the image is implemented by foreign matter.

4A and 4B are cross-sectional views illustrating a liquid crystal display panel according to an exemplary embodiment of the present invention.

5A and 5B show light radiated from a backlight unit to micro holes.

6A through 6D are cross-sectional views illustrating a method of repairing a liquid crystal display panel according to a first exemplary embodiment of the present invention.

7A to 7D are cross-sectional views illustrating a method of repairing a liquid crystal display panel according to a second exemplary embodiment of the present invention.

8A through 8D are cross-sectional views illustrating a method of repairing a liquid crystal display panel according to a third exemplary embodiment of the present invention in stages.

9 is a cross-sectional view illustrating a repair method of a liquid crystal display panel according to another exemplary embodiment of the present invention.

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

2, 102: upper substrate 4, 104: black matrix

6, 106: color filter 8, 108: upper alignment layer

9, 109: gate electrode 13, 113: pattern spacer

14, 114: semiconductor layer 16, 116: pixel electrode

18, 118: common electrode 32, 132: lower substrate

38, 138: lower alignment layer 40, 140: source electrode

42, 142: ohmic contact layer 44, 144: gate insulating film

47, 147: drain electrode 55, 155: foreign body

120: backlight unit 160: micro drill

161: laser 165: micro holes

260: opaque material 270: transparent material

410: colored pigment 420, 520: transparent pigment

510: colored electrode material

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display panel and a repair method thereof, and more particularly to a liquid crystal display panel and a repair method capable of improving yield by minimizing a defective rate by darkening a bright point.

In general, a liquid crystal display (LCD) displays an image by adjusting the light transmittance of the liquid crystal according to a video signal. To this end, the liquid crystal display includes a liquid crystal display panel in which liquid crystal cells are arranged in a matrix, and a driving circuit for driving the liquid crystal display panel.

The liquid crystal display is roughly classified into a twisted nematic (TN) mode using a vertical electric field and an in plan switch (IPS) mode using a horizontal electric field according to the electric field driving the liquid crystal.

The TN mode is a mode in which a liquid crystal is driven by a vertical electric field between a pixel electrode and a common electrode disposed to face the upper substrate. The TN mode has a large aperture ratio and a narrow viewing angle. On the other hand, the IPS mode is a mode for driving the liquid crystal by a horizontal electric field between the pixel electrode and the common electrode disposed side by side on the lower substrate has a large viewing angle has a disadvantage of small aperture ratio.

1 is a cross-sectional view showing a conventional TN mode liquid crystal display panel.

Referring to FIG. 1, the liquid crystal display panel of the conventional TN mode includes a black matrix 4, a color filter 6, a common electrode 18, and an upper alignment layer 8 that are sequentially formed on the upper substrate 2. An upper array substrate (or color filter array substrate), a TFT formed on the lower substrate 32, a lower array substrate composed of a pixel electrode 16 and a lower alignment layer 38, an upper array substrate and a lower array The liquid crystal 52 is injected into the internal space between the substrates.

Meanwhile, in the IPS mode liquid crystal display panel, the common electrode 18 is formed on the lower substrate 32, and a planarization layer (not shown) is formed on the upper substrate 2 to compensate for the step difference of the color filter 6.

In the upper array substrate, the black matrix 4 is formed on the upper substrate 2 in correspondence with the TFT region of the lower array substrate and the region of the gate lines and data lines not shown, and the color filter 6 is formed. Provide a cell area. The black matrix 4 prevents light leakage and absorbs external light to increase contrast. The color filter 6 is formed over the cell region separated by the black matrix 4 and the black matrix 4. The color filter 6 is formed for each of R, G, and B to implement R, G, and B colors. The common electrode 18 is supplied with a common voltage for controlling the movement of the liquid crystal. The pattern spacer 13 serves to maintain a cell gap between the upper array substrate and the lower array substrate.

In the lower array substrate, the TFTs overlap with the gate electrode 9 formed on the lower substrate 32 together with the gate line, and the semiconductor layers 14 and 42 overlapping the gate electrode 9 and the gate insulating film 44 therebetween. ) And source / drain electrodes 40 and 47 formed together with data lines (not shown) with semiconductor layers 14 and 42 interposed therebetween. This TFT supplies the pixel signal from the data line to the pixel electrode 16 in response to the scan signal from the gate line. The pixel electrode 16 is a transparent conductive material having a high light transmittance and is in contact with the drain electrode 47 of the TFT with the passivation layer 50 interposed therebetween. The upper and lower alignment layers 8 and 38 for liquid crystal alignment are formed by applying an alignment material such as polyimide and then performing a rubbing process.

If a defect occurs in each of the thin films of the upper array substrate and the lower array substrate of the conventional liquid crystal display panel, the liquid crystal display panel may be repaired by using a rework or a laser before bonding the upper array substrate and the lower array substrate. Is possible. However, when foreign matter is deposited between the thin film of the upper array substrate and the thin film of the liquid crystal display panel to which the lower array substrate is bonded, repair of the liquid crystal display panel by a rework, a laser, or the like is impossible.

FIG. 2 is a cross-sectional view illustrating misalignment caused by a foreign material inserted during a process, and FIG. 3 is a view illustrating bright spots that appear when an image is formed by a foreign material.

In general, when moving into a chamber for forming a predetermined thin film during the manufacturing process of the liquid crystal display panel or to a separate chamber or a third place for forming another thin film, the thin film and the thin film, for example, as shown in FIG. As described above, the foreign material 55 or the like is often deposited between the common electrode 18 and the upper alignment layer 8. Since the alignment layer positioned to correspond to the foreign material 55 is not rubbed uniformly during the rubbing process by the foreign material 55, a non-uniform alignment region A is generated in the liquid crystal display panel. In addition, a problem in which the foreign material 55 is mixed due to a phenomenon in which a part of the color filter is torn off due to a process defect or the like during the formation of the color filter frequently occurs.

Light leakage is generated in the liquid crystal display panel by the non-uniform alignment region A, and the light leakage interferes with the light transmittance of the liquid crystal, thereby causing bright spots to appear on the liquid crystal display panel. In general, when a high gray is implemented, a dark point is seen as a dark area by light leakage, and when a low gray is implemented, it is called a bright spot where the sun is bright by a light leak. Here, the human eye is relatively sensitive to bright spots rather than dark spots, thereby giving a stricter criterion for the bright spots than the dark spots when the panel is judged as unfavorable. Accordingly, a method for minimizing the defective rate of the panel due to bright spots is required.

Accordingly, it is an object of the present invention to provide a liquid crystal display panel and its repair method which can improve the yield by darkening the bright point to minimize the defective rate.

In order to achieve the above object, the liquid crystal display panel according to an embodiment of the present invention and the substrate; Holes formed at positions corresponding to regions in which bright spots appear on the substrate; And an opaque material filled in the hole.

The opaque material is partially filled at the bottom of the hole.

The liquid crystal display panel further includes a transparent material filled in an upper portion of the hole.

The substrate includes an upper substrate and a lower substrate bonded to each other with a liquid crystal interposed therebetween.

The liquid crystal display panel further includes a black matrix and a color filter formed on the upper substrate.

The opaque material includes colored pigments.

The colored pigment includes a material that realizes the same color as the color filter positioned in a region corresponding to the region where the bright spots appear.

The colored pigment is the same material as the color filter positioned in the region corresponding to the region where the bright spot appears.

The colored pigment includes a material capable of implementing black and gray colors.

The opaque material includes colored electrode material.

The colored electrode material is the same material as the black matrix.

The diameter of the hole is about 20㎛ ~ 500㎛.

According to one or more exemplary embodiments, a method of repairing a liquid crystal display panel may include preparing a substrate; Determining an area in which bright spots appear on the substrate; Forming holes on the substrate corresponding to regions where the bright spots appear; Filling the hole with an opaque material.

The hole is formed using at least one of microdrill, micromilling or laser.

The wavelength of the said laser is about 50 nm-300 nm.

Filling the opaque material in the hole includes filling the opaque material in the bottom of the hole.

Filling the opaque material in the lower portion of the hole, the step of applying an opaque material to the entire hole; Partially removing the opaque material using an etchant.

The repairing method of the liquid crystal display panel may further include filling a transparent material on an upper portion of the hole.

The opaque material formed in the hole is formed by any one of vacuum deposition, spray spraying and sputtering.

Other objects and features of the present invention in addition to the above object will be apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 4A to 9.

4A and 4B are cross-sectional views illustrating a liquid crystal display panel according to an exemplary embodiment of the present invention.

4A and 4B, the liquid crystal display panel 170 according to the exemplary embodiment of the present invention may include a black matrix 104, a color filter 106, a common electrode 118, sequentially formed on the upper substrate 102. An upper array substrate (or “color filter array substrate”) composed of a pattern spacer 113 and an upper alignment layer 108, a TFT formed on the lower substrate 132, a pixel electrode 116 and a lower alignment layer 138. And a liquid crystal 152 injected into an inner space between the lower array substrate (or “thin film transistor substrate”) and the upper array substrate and the lower array substrate.

In the upper array substrate, the black matrix 104 is formed on the upper substrate 102 to correspond to the TFT region of the lower plate and the gate line and data line regions (not shown), and the cell region where the color filter 106 is to be formed. To prepare. The black matrix 104 is formed of polyimide mixed with carbon-based pigments to prevent light leakage and to absorb external light to increase contrast. The color filter 106 is formed over the cell region separated by the black matrix 104 and the black matrix 104. The color filter 106 is formed for each of R, G, and B to implement R, G, and B colors. The common electrode 118 is supplied with a common voltage for controlling the movement of the liquid crystal. The pattern spacer 113 serves to maintain a cell gap between the upper array substrate and the lower array substrate.

In the lower array substrate, the TFTs overlap the gate electrodes 109 formed on the lower substrate 132 together with the gate lines, and the semiconductor layers 114 and 147 overlapping the gate electrodes 109 and the gate insulating layer 144 therebetween. ) And source / drain electrodes 140 and 142 formed together with data lines (not shown) with semiconductor layers 114 and 147 interposed therebetween. This TFT supplies the pixel signal from the data line to the pixel electrode 116 in response to the scan signal from the gate line.

The pixel electrode 116 is a transparent conductive material having a high light transmittance and contacts the drain electrode 142 of the TFT with the passivation layer 150 therebetween. The upper and lower alignment layers 108 and 138 for liquid crystal alignment are formed by applying an alignment material such as polyimide and then performing a rubbing process. Meanwhile, in the IPS mode liquid crystal display panel, a common electrode 118 is formed on the lower substrate 132 and a flattening layer (not shown) to compensate for the step difference of the color filter 106 on the color filter 106 on the upper substrate 102. Not formed).

In the liquid crystal display panel 170 according to an exemplary embodiment of the present invention, bright spots are generated in a region in which an alignment defect of the liquid crystal display panel 170 is generated due to a misalignment caused by a foreign material 155 mixed in the liquid crystal display panel 170. In this case, the micro holes 165 are formed in any one of the upper and lower substrates 102 and 132 of the upper substrate 102 and the lower substrate 132, and the opacity is formed in the formed micro holes 165. Material 260 is filled. The transparent material 270 may be filled in the upper portion of the microhole 165 filled with the opaque material 260 in the lower portion.

The opaque material 260 filled in the micro holes 165 blocks the light irradiated to the liquid crystal display panel 170 from the backlight unit 120 disposed on the rear of the lower array substrate as shown in FIG. 5A. The display panel 170 darkens an area in which alignment failure occurs, that is, an area in which bright points are generated. As a result, the yield of the liquid crystal display panel 170 is improved, such as the failure rate of the liquid crystal display panel 170 is minimized.

At this time, the opaque material 260 filled in the micro holes 165 is filled only in the lower portion of the micro holes 165 to prevent the decrease of the aperture ratio of the cell adjacent to the micro holes 165.

Referring to FIG. 5B, when the microhole 165 is filled with the opaque material 260, the area where the bright point is generated from the backlight unit 120 by the opaque material 260 filled with the microhole 165 is filled. As the light irradiated to the light is irradiated to the cells adjacent to the micro holes 165, the aperture ratio of the cells adjacent to the micro holes 165 is reduced. That is, to prevent this, the opaque material 260 fills only the bottom of the micro hole 165.

The micro holes 165 are formed through a micro drill, and the micro holes 165 may have a thickness of about 20 μm depending on the size of the liquid crystal display panel 170 and the degree of light leakage generated by the mixed foreign matter 155. It is formed to 500 mu m.

As the micro drill, an end drill may be used to form a round micro hole 165 and a straight micro hole 165 according to the shape of the foreign material 155 to be mixed. Here, as an apparatus for forming the micro holes 165, micro milling may be used in addition to the micro drill. Micro milling may form micro holes 165 of more precise and various shapes compared to micro drills.

Hereinafter, a repair method of the liquid crystal display panel according to the first embodiment of the present invention will be described with reference to FIGS. 6A to 6D.

The formation of the micro holes 165 according to an embodiment of the present invention will be described only for the formation of the micro holes 165 using the micro drills during the above-described micro drill and micro milling. Formation is omitted since it is the same as in the case of using a micro drill.

In addition, the repair of the liquid crystal display panel 170 according to the embodiment of the present invention is formed on one of the substrates 102 and 132 of the upper substrate 102 and the lower substrate 132 of the liquid crystal display panel 170. Although the hole 165 is used, the repair of the liquid crystal display panel 170 according to the exemplary embodiment of the present invention only describes the repair of the liquid crystal display panel 170 using the micro holes 165 formed on the lower substrate 132. The repair of the liquid crystal display panel 170 using the micro holes 165 formed on the upper substrate 102 is a repair of the liquid crystal display panel 170 using the micro holes 165 formed on the lower substrate 132. Since it is the same as, it will be omitted.

Referring to FIG. 6A, when a bright point is generated in the liquid crystal display panel 170 by, for example, foreign matter 155 mixed between the common electrode 118 and the upper alignment layer 108, the micro drill 160 may be used. As a result, the micro holes 165 are formed in the lower substrate 132 corresponding to the area where the bright spot is generated.

Subsequently, the micro holes 165 formed on the lower substrate 132 by using ink jet or the like are colored pigments 410, in particular, black or gray pigments, as shown in FIG. 6B. Drop to fill the bottom of the micro-hole 165. In this case, the material of the colored pigment 410 may be the same material as the color filter 106 corresponding to the region in which the foreign material 155 is mixed, or a material that implements the same color.

Then, the transparent pigment 420 is filled in the upper portion of the micro hole 165 filled with the colored pigment 410 in the lower portion as shown in FIGS. 6C and 6D.

As described above, in the repairing method of the liquid crystal display panel according to the first exemplary embodiment of the present invention, when a bright point is generated in the liquid crystal display panel 170, the lower substrate 132 corresponding to a region where the bright point of the liquid crystal display panel 170 is generated. The micro holes 165 are formed using the micro drill 160 or the micro milling, and the colored holes 165 are filled in the formed micro holes 165 to darken the area where the bright spot is generated. It is possible to reduce the occurrence of bright spots by preventing the light emitted from the si) from passing outside. Accordingly, the yield of the liquid crystal display panel 170 is improved, such as the failure rate of the liquid crystal display panel 170 is minimized.

7A to 7D are cross-sectional views illustrating a method for repairing a liquid crystal display panel according to a second exemplary embodiment of the present invention.

7A and 7B, in the repairing method of the liquid crystal display panel 170 according to the second embodiment of the present invention, the micro holes 165 formed in the region corresponding to the region where the bright point is generated in the liquid crystal display panel 170. ) To fill the micro holes 165 by dropping a colored pigment 410, in particular a black or gray pigment. Here, the material of the colored pigment 410 may be the same material as the color filter 106 corresponding to the region in which the foreign material 155 is mixed, or a material implementing the same color.

Then, an etchant for removing the colored pigment 410 is applied to the upper portion of the micro hole 165 filled with the colored pigment 410 as shown in FIG. 7C, and the coated etchant is shown in FIG. 7D. As described above, the colored pigment 410 applied to the area except the lower portion of the micro hole 165 is removed. Here, the colored pigment 410 applied to the lower portion of the micro hole 165 is not easily removed by an etchant because the micro hole 165 does not penetrate the lower substrate 132, whereas the lower substrate 132 is not easily removed. The colored pigment 410 applied above and the colored pigment 410 applied on top of the micro holes 165 are easily removed by the etchant.

In this case, the transparent pigment 410 may be filled in the upper portion of the micro hole 165 from which the colored pigment 410 is removed by the etchant, as shown in FIGS. 6C and 6D.

As described above, in the repairing method of the liquid crystal display panel according to the second exemplary embodiment of the present invention, when a bright point is generated in the liquid crystal display panel 170, a lower substrate corresponding to an area where the bright point of the liquid crystal display panel 170 is generated ( In the backlight unit by forming a micro hole 165 using a micro drill 160 or a micro milling in 132, and filling a colored pigment 410 in the formed micro hole 165 to darken the area where the bright spot is generated. By preventing the emitted light from passing outside, the occurrence of bright spots can be reduced. Accordingly, the yield of the liquid crystal display panel is improved by minimizing the defective rate of the liquid crystal display panel.

8A through 8D are cross-sectional views illustrating a method of repairing a liquid crystal display panel according to a third exemplary embodiment of the present invention.

Referring to FIG. 8A, the repairing method of the liquid crystal display panel 170 according to the third exemplary embodiment of the present invention is colored in the micro holes 165 formed in a region corresponding to a region where a bright point of the liquid crystal display panel 170 is generated. The electrode material 510, in particular, a black electrode material such as chromium (Cr) or molybdenum (Mo) is deposited on the lower substrate 132 on which the micro holes 165 are formed using a deposition method such as vacuum deposition.

Then, an etchant for removing the colored electrode material 510 is applied to the lower substrate 132 as shown in FIG. 8B, and the micro holes 165 as shown in FIG. 8C using the applied etchant. The colored electrode material 510 formed in the region except for the lower portion of the substrate is removed. Here, since the micro holes 165 formed on the lower substrate 132 do not penetrate the lower substrate 132, the colored electrode material 510 filled in the micro holes 165 is not easily removed by an etchant. On the other hand, the colored electrode material 510 deposited on the lower substrate 132 is easily removed by the etchant.

In this case, the transparent pigment 520 may be filled in the upper portion of the micro hole 165 from which the colored electrode material 510 is removed by the etchant.

Here, in the description related to the third embodiment of the present invention, only the case where the colored electrode material 510 is filled in the micro holes 165 by using a deposition method such as vacuum deposition is described, but by using a deposition method such as vacuum deposition. The micro holes 165 may be filled with the above-described colored pigment.

As described above, in the repairing method of the liquid crystal display panel according to the third exemplary embodiment of the present invention, when a bright point is generated in the liquid crystal display panel 170, the lower substrate 132 corresponding to a region where the bright point of the liquid crystal display panel 170 is generated. The micro holes 165 are formed by using a micro drill or micro milling, and the colored light emitted from the backlight is filled by filling the colored electrode material 510 in the formed micro holes 165 to darken the area where the bright spot is generated. It is possible to reduce the occurrence of bright spots by preventing them from passing through. Accordingly, the yield of the liquid crystal display panel 170 is improved, such as the failure rate of the liquid crystal display panel 170 is minimized.

In the liquid crystal display panel of FIG. 9, when a bright spot is generated due to a misalignment caused by foreign matter or the like mixed in the liquid crystal display panel 170, a laser is applied to the lower substrate 132 corresponding to the region where the bright spot is generated. The micro holes 165 may be formed using the 161, and the area where the bright spot is generated may be darkened by filling the formed micro holes 165 with the opaque material 260 in the same manner as the above-described repair method. Here, the laser 161 used to form the micro holes 165 includes an ND YAG laser having a wavelength of 266 nm, and may also include other lasers having a wavelength of 50 nm or more and 300 nm or less.

As such, the method of darkening the region where the bright spot is formed by forming the micro hole 165 on one of the upper substrate 102 and the lower substrate 132 corresponding to the bright spot is generated in the liquid crystal of IPS mode. In addition to the display panel and the liquid crystal display panel of the TN mode, it can be easily applied to the liquid crystal display panel of the ECB (Electrical Controlled Birefringence), and also VA (Vertical Alignment) mode.

As described above, the liquid crystal display panel and the repair method according to the embodiment of the present invention, when the bright spot is generated due to a process problem during the manufacturing process of the liquid crystal display panel, the upper substrate corresponding to the region where the bright spot is generated and Micro holes may be formed on one of the lower substrates, and the area where the bright spot is generated may be darkened by filling the formed micro holes with an opaque material. Accordingly, the yield of the liquid crystal display panel is improved by minimizing the defective rate of the liquid crystal display panel.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the 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.

Claims (22)

A substrate; Holes formed at positions corresponding to regions in which bright spots appear on the substrate; With an opaque material filled in the hole, The opaque material is partially filled in the lower part of the hole, And a transparent material filling the upper portion of the opaque material in the hole. delete delete Claim 4 has been abandoned due to the setting registration fee. The method of claim 1, And the substrate includes an upper substrate and a lower substrate bonded to each other with a liquid crystal interposed therebetween. Claim 5 was abandoned upon payment of a set-up fee. The method of claim 4, wherein The method of claim 1, The opaque material includes a colored pigment. The method of claim 6, Wherein the colored pigment comprises a material which realizes the same color as a color filter positioned in a region corresponding to a region where the bright spot appears. The method of claim 6, The colored pigment is a liquid crystal display panel, characterized in that the same material as the color filter located in the region corresponding to the region where the bright spot appears. The method of claim 6, The colored pigment is a liquid crystal display panel comprising a material capable of realizing black and gray. The method of claim 1, The opaque material includes a colored electrode material. 11. The method of claim 10, The colored electrode material is a liquid crystal display panel, characterized in that the same material as the black matrix. The method of claim 1, The diameter of the hole is a liquid crystal display panel, characterized in that 20㎛ ~ 500㎛. Providing a substrate; Determining an area in which bright spots appear on the substrate; Forming holes on the substrate corresponding to regions where the bright spots appear; Partially filling an opaque material in the lower portion of the hole; And filling the transparent material over the opaque material in the hole. The method of claim 13, The hole may be formed using any one of a microdrill, a micromilling, or a laser. 15. The method of claim 14, The wavelength of the laser is a repair method of the liquid crystal display panel, characterized in that 50nm ~ 300nm. delete The method of claim 13, Filling the opaque material in the lower portion of the hole, Applying an opaque material to the entire hole; And partially removing the opaque material using an etchant. delete The method of claim 13, The opaque material is a repair method of a liquid crystal display panel, characterized in that the same material as any one of the black matrix and color filters. 20. The method of claim 19, And wherein the opaque material includes a material that realizes the same color as the color filter positioned in a region corresponding to the region where the bright spot appears. The method of claim 13, The opaque material repair method of a liquid crystal display panel comprising any one of a colored pigment and a colored electrode material. 22. The method of claim 21, The opaque material formed in the hole is a repair method of a liquid crystal display panel, characterized in that formed by any one of a vacuum deposition method, spray injection method and sputtering.

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