KR101224455B1 - In-plane switching mode liquid crystal display and method for repairing the same - Google Patents

Abstract

The present invention is to visually defect-free drive a bad pixel by interlocking with adjacent normal pixels, and includes a transparent insulating substrate and gate lines and data lines formed in a horizontal and vertical direction on the transparent insulating substrate to define a plurality of pixels. And thin film transistors disposed at intersections of the gate lines and the data lines, pixel electrodes connected to the thin film transistors, common electrodes arranged to cross the pixel electrodes, and connecting the common electrodes to each other. Provided is a transverse electric field liquid crystal display including a common line and island-shaped repair patterns disposed between two adjacent pixels such that overlap regions at both ends thereof overlap pixel electrodes of two adjacent pixels, and a repair method thereof. do.

Liquid Crystal Display, Array Board, Repair Process, Laser Welding

Description

Transverse electric field type liquid crystal display device and its repair method {In-plane switching mode liquid crystal display and method for repairing the same}

1 and 2 are plan views of an array substrate for a liquid crystal display device according to the prior art.

FIG. 3 is a diagram for describing an inspection process that is generally performed after completing an array substrate of a liquid crystal display.

4 is a plan view illustrating a portion of an array substrate in a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 5 is a diagram for describing a repair process of FIG. 4.

FIG. 6 is a cross-sectional view illustrating a change in a line III according to the repair process of FIG. 5.

FIG. 7 is a partial plan view illustrating a modified form of the repair pattern illustrated in FIG. 4.

8 is a flowchart illustrating a repairing method of a liquid crystal display according to an exemplary embodiment of the present invention.

9 is a comparison table for explaining the effects of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS (S)

100: transparent insulating substrates P1, P2,... Pixel

110: gate line 120: data line

121: source electrode 122: drain electrode

130: common line 131: common electrode

140: pixel electrode 150: repair pattern

The present invention relates to a liquid crystal display and a repair method thereof, and more particularly, to a transverse electric field type liquid crystal display device and a repair method thereof.

The liquid crystal display device forms a liquid crystal layer having anisotropic dielectric constant between the color filter substrate, which is the upper and lower transparent insulating substrates, and the array substrate, and then adjusts the intensity of the electric field formed in the liquid crystal layer to change the molecular arrangement of the liquid crystal material. The display device expresses a desired image by adjusting the amount of light transmitted through the color filter substrate. As the liquid crystal display, a thin film transistor liquid crystal display (TFT LCD) using a thin film transistor (TFT) as a switching element is mainly used.

1 and 2 are plan views of an array substrate for a liquid crystal display according to the related art, and show an array substrate used in a twisted nematic (TN) structure and an in-plane switching (IPS) structure, respectively.

A conventional array substrate is composed of a plurality of pixels defined by gate lines 10 and 40 and data lines 20 and 50 orthogonal to each other, as shown in FIGS. 1 and 2. Source electrodes 21 and 51 and drains facing each other with gate electrodes 11 and 41 extending from 40, semiconductor layers (not shown) on gate electrodes 11 and 41, and semiconductor layers (not shown) interposed therebetween. Electrodes 22 and 52 are formed to form a thin film transistor.

In the case of the TN structure, as illustrated in FIG. 1, the pixel electrode 30 is formed to be connected to the drain electrode 22 to display an image by generating an electric field perpendicular to a common electrode (not shown) on the color filter substrate.

In addition, referring to FIG. 2, in the case of the IPS structure, the gate line 40 and the common line 70 are arranged in parallel in the horizontal direction on the array substrate, and the data line 50 is disposed in the vertical direction in the gate line 40. And perpendicular to the common line 70.

The common electrodes 71 branched from the common line 70 and the pixel electrodes 61 connected to the drain electrode 52 are alternately formed to generate an electric field in a horizontal direction.

FIG. 3 is a diagram for describing an inspection process that is generally performed after completing an array substrate of a liquid crystal display.

After the array substrate is completed through the TFT array process (S10), the array test process (S11) is performed before manufacturing the liquid crystal panel by performing the liquid crystal cell process in which the array substrate and the color filter substrate are bonded and the liquid crystal layer is formed. Through the inspection of the defective array substrate is completed.

In the array test process S11, a constant test signal is applied to the gate pad and the data pad on the completed array substrate to check the on / off state of the thin film transistors formed on the array substrate. When the thin film transistors are in the on state, the test signal is applied through the data lines on the data pad to check the pixel lighting state.

If a defective product is found through such an array test process (S11), the defective product inspection operation (S12) is performed to determine the form of the defect, whether repair is possible, etc. using the naked eye or an optical apparatus.

As a result of the defective product inspection, when the degree of defect is severe and the number of the defective pixels is greater than the reference value, the repair process is not performed. When the number of the defective pixels is in the reference value region, the repair process S13 is performed for each defective pixel. .

In the case of a defective pixel, the pixel is always on and appears as a bright point on the liquid crystal panel, or is always dark and appears as a dark spot on the liquid crystal panel, and the pixel which is always on is repaired using a laser. Step S13 is performed to darken the data voltage so as not to be applied to the pixel electrode.

That is, in the repair process (S13), when there are defective pixels that are always in the on state, patterning is normalized by using a laser again to normalize them, or as shown in FIGS. 1 and 2, portions of the drain electrodes 22 and 52 of the thin film transistor. After cutting (a1, a2), the pixel electrode 30 is brought into contact with the gate line 10, or the pixel electrode 61 is brought into contact with the common electrode 71 to darken.

However, when the repair process (S13) is performed in this manner, the repaired pixels always exist only as dark spots, and the pixels of the darkened spots are not easily recognized as compared to the bright spots but are easily recognized by the user. There was this.

In addition, when the drain electrodes 22 and 52 of the thin film transistor connected to the pixel electrodes 30 and 61 are cut in order to repair the pixel electrodes 30 and 61 (a1 and a2), adjacent source electrodes 21 and 51 are cut. ) And a short between the drain electrodes 22 and 52 and the gate electrodes 11 and 41 easily occurs.

Accordingly, an object of the present invention is to provide a transverse electric field type liquid crystal display device in which a bad point is not easily recognized in a general image by visually making defects by driving a bad pixel cooperatively with an adjacent normal pixel.

In addition, another technical problem to be achieved by the present invention is to provide a transverse electric field type liquid crystal display device which can easily perform a repair process not only in the array substrate state before bonding to the liquid crystal panel but also in the liquid crystal panel state after the bonding.

Another object of the present invention is to provide a repair method of a transverse electric field type liquid crystal display device capable of efficiently repairing such a liquid crystal display device.

Technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

According to an aspect of the present invention, a transverse electric field type liquid crystal display device includes a transparent insulating substrate and gate lines crossing the horizontal and vertical directions on the transparent insulating substrate to define a plurality of pixels. And a gate electrode on the gate line, a semiconductor layer on the gate electrode, a source electrode branched from the data line, and the semiconductor layer, disposed at an intersection of each of the data lines and the gate lines and the data lines. A thin film transistor including a drain electrode facing the source electrode, a pixel electrode connected to the drain electrode, common electrodes disposed to cross the pixel electrodes, and connecting the common electrodes to each other; Pixel electrodes of two pixels adjacent to common lines and overlap regions at both ends And characterized by including the repair of an island-like pattern is configured so as to overlap respectively.

The repair pattern is preferably configured to have a symmetrical shape, and is configured to be an independent island-shaped pattern or to be connected to the common electrode.

Each of the plurality of pixels may be configured to have a structure that is bent in the vertical direction.

In the defective pixel of some of the plurality of pixels, the thin film transistor is cut off from the pixel electrodes, the repair pattern is cut off from the common line, and is adjacent to each other through overlap regions of both sides. And an electrical contact with the pixel electrodes of the normal pixel.

In a repairing method of a transverse electric field type liquid crystal display device according to a preferred embodiment of the present invention, the repair pattern is formed of a plurality of pixels which are switched by a thin film transistor having a gate electrode, a semiconductor layer, and a source and a drain electrode. And a repair pattern, the array substrate having both ends overlapping pixel electrodes between two adjacent pixels, and detecting a bad pixel by applying a test signal to each of the plurality of pixels. Cutting the thin film transistor of the defective pixel, and forming both ends of a repair pattern overlapped with the defective pixel and pixel electrodes of a normal pixel adjacent to the defective pixel. And electrically contacting the electrodes.

After manufacturing the array substrate, the method may further include manufacturing a liquid crystal panel using the array substrate.

In the manufacturing of the array substrate, the repair pattern may be formed as an independent island pattern, or may be connected to common electrodes applying a common voltage to the plurality of pixels, and the repair pattern may be provided in the defective pixel. When connected to the common electrode, cutting may be further included from the connected common electrode.

The repair pattern is preferably formed to have a symmetrical shape.

Each of the plurality of pixels may be configured to have a structure that is bent in the vertical direction.

Laser cutting and laser welding processes can be used for cutting and electrical contact.

Specific details of other embodiments are included in the detailed description and the drawings. Advantages and features of the present invention, and methods of achieving the same will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. Like reference numerals refer to like elements throughout.

Hereinafter, a transverse electric field type liquid crystal display device and a repair method thereof according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

4 is a plan view illustrating a portion of an array substrate in a liquid crystal display according to an exemplary embodiment of the present invention.

The liquid crystal display according to the exemplary embodiment of the present invention includes a plurality of pixels, such as P1 and P2 illustrated in FIG. 4, and includes horizontal gate lines 110 crossing each other and data lines 120 perpendicular to each other. The pixels are divided into regions, and a common line 130 parallel to the gate line 110 is formed for each pixel to apply a common voltage to the common electrodes 131 of each pixel.

The thin film transistor is formed at the intersection of the gate line 110 and the data line 120. The thin film transistor includes a gate electrode defined as a partial region on the gate line 110, a semiconductor layer on the gate electrode (not shown), a source electrode 121 branched from the data line 120, and a semiconductor layer (not shown). And a drain electrode 122 disposed to face the source electrode 121.

As shown in FIG. 4, the drain electrode 122 of the thin film transistor is formed in an I shape and connected to the pixel electrode 140, and the source electrode 121 has a U shape surrounding the drain electrode 122. And is connected to the data line 120. That is, the U-shaped source electrode 121 having a concave groove is formed, and the drain electrode 122 is formed to be positioned at regular intervals from the source electrode 121 in the groove of the source electrode 121. will be.

The drain electrode 122 and the source electrode 121 overlap the gate electrode defined as a partial region on the gate line 110 by a predetermined area.

In the vertical direction, the common electrodes 131 and the pixel electrodes 140 are disposed to cross each other to form an electric field in the horizontal direction.

Here, the common electrode 131 and the pixel electrode 140 may be in a straight line shape, or may be bent as shown in FIG. 4, or the data line 120 may also be bent in all the shape. By making it parallel to 140, each of the plurality of pixels can be configured to have a structure bent in the vertical direction.

In the structure in which each pixel is bent, domains having different arrangement directions of liquid crystal molecules in the space between the common electrode 131 and the pixel electrode 140 are divided, so that the transverse electric field on the array substrate is in only one direction. Compared with the case of forming, the color shift phenomenon is improved, the viewing angle characteristic is improved, and the response speed is increased.

In some regions of the common electrode 131, an outer portion of the common electrode 131 is separated from another region of the common electrode 131, and only one side of the common electrode 131 is formed with an island-shaped repair pattern 150.

The repair pattern 150 is disposed between two adjacent pixels such as P1 and P2 so that the overlap regions at both ends thereof overlap the pixel electrodes 140 of the two adjacent pixels, respectively. In the case of FIG. 4, the repair pattern 150 is formed such that both ends thereof are interposed between the pixel electrode 140 of P1, which is a pixel located above, and the pixel electrode 140 of P2, which is a pixel located below.

The repair pattern 150 has a structure in which a defective pixel is easily changed into an independent island-shaped pattern when a bad pixel is detected. As shown in the repair pattern 150 of FIG. 4, two adjacent pixels P1 and P2 Both should include an overlap region overlapping with the repair pattern 150, and the two pixels have a symmetrical shape in an adjacent direction (vertical direction in FIG. 4) so that the overlap regions on both sides overlap with the same area. good.

This array substrate is manufactured and used as a liquid crystal panel including a color filter substrate and a liquid crystal layer formed between the two substrates. The array substrate is driven to form a horizontal electric field between the common electrode 131 and the pixel electrode 140 to control the alignment of the liquid crystal layer for each pixel, and the color filter substrate includes red, green, and blue color filters. According to the alignment of the liquid crystal material, light is transmitted per wavelength to display an image.

FIG. 5 is a view for explaining the repair process of FIG. 4, and FIG. 6 is a cross-sectional view illustrating a change in a line II according to the repair process of FIG. 5.

When the number of defective pixels on the array substrate is in the reference region, the repair process is performed to visually defect the defective pixels using the structure of the repair pattern 150.

For example, in the structure of FIG. 4, assuming that P1 is a bad pixel and that P2 adjacent to P1 is a normal pixel, first of all, the thin film transistor of P1 is provided through laser cutting of c1. The drain electrode 122 is disconnected.

In addition, the repair pattern 150 formed between the pixel electrode 140 of P1 and the pixel electrode 140 of P2 is disconnected from the common electrode 131 by laser cutting of c2, thereby preventing the pixel between two pixels P1 and P2. An overlapping region of the pixel electrodes 140 of P1 and P2 and the repair pattern 150 overlapping the pixel electrodes 140 may be formed as an independent island-shaped pattern for linking the electrodes 140, and laser welding of c3 and c4. P1 is repaired by shorting.

Then, as illustrated in FIG. 6, the pixel electrodes 140 of P1 and P2 that are separated from each other are connected to each other through the repair pattern 150, and the data voltage applied to P2, which is a normal pixel, also drives P1, which is a bad pixel. As P1 and P2 display the same gray level, visual imperfections are possible.

Referring to FIG. 6, in the state d1 before the repair process, the repair pattern 150 in an isolation state is formed on the transparent insulating substrate 100, and P1 and P2 are disposed with the protective film 101 interposed therebetween. Each pixel electrode 140 is formed, and a common voltage is applied to the repair pattern 150, and a respective data voltage is applied to the pixel electrodes 140 of P1 and P2.

In the state d2 after the repair process, the pixel electrodes 140 of P1 and P2 are electrically contacted with each other through points c3 and c4 so that the data voltage applied to the pixel electrode 140 of P2 is the pixel electrode 140 of P1. Is passed to.

FIG. 7 is a partial plan view illustrating a modified form of the repair pattern illustrated in FIG. 4.

4 to 6 illustrate a case in which one repair pattern 150 is formed between two adjacent pixels as in P1 and P2, and one side of the formed repair pattern 150 is connected to the common electrode 131. However, the present invention is not limited thereto and may be modified in various forms.

For example, in order to secure contact characteristics during the repair process, a plurality of such repair patterns 150 may be formed, or as shown in FIG. 7, the repair patterns 150 may be formed in an intrinsically independent island-shaped pattern c2. It is possible to repair by only laser welding of c3 and c4 without having to perform the laser cutting of.

Conventionally, when there are defective pixels, a pattern is formed again with a laser or darkened as it is. However, in the present invention, the repair pattern 150 is formed in advance in the array process, and the laser cutting is not necessary during the repair process. The defective pixels can be repaired using only the laser welding. Therefore, there is an advantage that the repair process can be performed not only in the array substrate state but also in the state in which the array substrate is manufactured as the liquid crystal panel through the liquid crystal cell process.

FIG. 8 is a flowchart illustrating a repairing method of a liquid crystal display according to an exemplary embodiment of the present invention. Hereinafter, an example in which P1 is a bad pixel and P2 is a normal pixel in an array substrate having the structure of FIG. 4 will be described. Shall be.

First, a TFT array process for manufacturing an array substrate through steps S100 to S120, a color filter process for manufacturing a color filter substrate, and a liquid crystal cell process for bonding two substrates together and forming a liquid crystal layer therebetween are performed. Will be configured.

The array substrate may include a gate electrode serving as a partial region on the gate line 110, a source electrode 121 and a drain electrode facing each other with a semiconductor layer (not shown) and a semiconductor layer (not shown) on the gate electrode interposed therebetween. Comprising a plurality of pixels (P1, P2, ...) to be switched by a thin film transistor having a 122, island-shaped repair pattern 150 is formed, both ends of each repair pattern 150 is adjacent It is configured to overlap each of the pixel electrodes 140 between the pixels (eg, P1 and P2).

The repair patterns 150 on the array substrate may be formed in a form connected to the common electrode 131 applying a common voltage Vcom to each pixel P1, P2,..., Or in an independent island pattern.

Red, green, and blue color filters, a black matrix, and the like are formed on the color filter substrate, and light is transmitted for each wavelength in accordance with driving of the array substrate to display an image.

The repair process according to the present invention can be applied to both the array substrate state and the liquid crystal panel state, and when the repair process is performed in the array substrate state, steps S110 and S120 are omitted.

Next, in operation S130, a bad signal P1 is detected by applying a test signal to the pixels P1, P2,..., On the array substrate.

Next, in operation S140, the drain electrodes 122 of the thin film transistor included in the bad pixel P1 are cut by laser cutting.

Next, in step S150, by laser welding the both ends of the repair pattern 150 configured to overlap between the bad pixel P1 and the pixel electrodes 140 of the normal pixel P2 adjacent to the bad pixel P1. The pixel electrodes 140 of the two pixels P1 and P2 are linked through the repair pattern 150.

When the repair patterns 150 on the array substrate are configured to be connected to the common electrode 131, the common electrode 131 to which the repair pattern 150 provided in the bad pixel P1 is connected using a laser before step S140. It will further comprise the step of disconnecting from.

As described above, by driving the defective pixel P1 with the normal pixel P2 adjacent to the upper or lower position, the visual defect may be realized such that the defect is not recognized when the image is displayed.

8 is a comparison table for explaining the effect of the present invention, comparing the recognition characteristics when the upper and lower pixels (up and down adjacent adjacent pixels and normal pixels) by applying the present invention and the dark point according to the prior art It is.

If white, gray and black levels are displayed on the screen, when repaired and darkened according to the prior art, it is recognized as bad in all gray except the black level as shown on the right. In the case where the upper and lower pixels are linked according to the present invention, no defective point is recognized in any gray as in the left side.

When a line is displayed on the screen, the defect is recognized only when the defective pixel is caught directly above the line in the present invention, whereas the defect is recognized in all grays except the black level in the prior art.

When a picture having various grays is displayed on the screen, in the present invention, since a bad pixel displays gray similar to an adjacent normal pixel, it is not well recognized as a bad even at the boundary of the image. This is recognized.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand.

Therefore, it should be understood that the above-described embodiments are provided so that those skilled in the art can fully understand the scope of the present invention. Therefore, it should be understood that the embodiments are to be considered in all respects as illustrative and not restrictive, The invention is only defined by the scope of the claims.

According to the transverse electric field type liquid crystal display device and the repair method thereof according to the preferred embodiment of the present invention as described above, the defect point is not easily recognized in the general image by visually defecting the defective pixel by cooperatively driving the adjacent pixel. You can do that.

Further, according to the transverse electric field type liquid crystal display device and the repair method thereof according to the preferred embodiment of the present invention, the repair process can be easily performed not only in the array substrate state before bonding to the liquid crystal panel but also in the liquid crystal panel state after the bonding. .

Claims (11)

Transparent insulating substrates; Gate lines and data lines intersecting in the horizontal and vertical directions on the transparent insulating substrate to define a plurality of pixels; A gate electrode disposed at an intersection of each of the gate lines and the data lines, and defined as a partial region of the gate line, a semiconductor layer on the gate electrode, a source electrode branched from the data line, and the semiconductor layer; A thin film transistor having a drain electrode facing the source electrode; Pixel electrodes connected to the drain electrode, and common electrodes disposed to alternate with the pixel electrodes; Common lines connecting the common electrodes to each other; And And an island-shaped repair pattern configured to overlap an overlap region at both ends thereof with pixel electrodes of two adjacent pixels, respectively. The method of claim 1, The repair pattern is, A transverse electric field liquid crystal display device having a symmetrical shape. The method of claim 1, Each of the plurality of pixels, A transverse electric field liquid crystal display device having a structure which is bent in the vertical direction. The method of claim 1, The repair pattern is, A transverse electric field liquid crystal display comprising a separate island pattern or connected to the common electrode. 5. The method of claim 4, In some bad pixels of the plurality of pixels, The thin film transistor is cut off from the pixel electrodes, and the repair pattern is cut off from the common line and electrically contacted with the pixel electrodes of adjacent normal pixels through overlap regions on both sides. A transverse electric field liquid crystal display device characterized by the above-mentioned. Comprising a plurality of pixels that are switched by a thin film transistor having a gate electrode, a semiconductor layer, and a source and drain electrodes, an island-shaped repair pattern is formed, the repair pattern is a pixel electrode between two pixels adjacent to both ends Manufacturing an array substrate configured to overlap with; Detecting a bad pixel by applying a test signal to each of the plurality of pixels; Cutting the thin film transistor of the defective pixel; And And electrically contacting the defective pixels and both ends of a repair pattern overlapping the pixel electrodes of the normal pixel adjacent to the defective pixel to the defective pixels and the pixel electrodes of the normal pixel. Repair method of electric field type liquid crystal display device. The method of claim 6, And after the array substrate is manufactured, manufacturing a liquid crystal panel using the array substrate. The method of claim 6, In the manufacturing of the array substrate, the repair pattern may be formed as an independent island pattern, or may be connected to common electrodes applying a common voltage to the plurality of pixels. And when the repair pattern included in the bad pixel is connected to the common electrode, cutting the connected pattern from the connected common electrode. The method of claim 6, The repair pattern is, The repairing method of the transverse electric field type liquid crystal display device which is formed so that it may have a symmetrical shape. The method of claim 6, Each of the plurality of pixels, The repair method of the transverse electric field type liquid crystal display device which has a structure bent in the vertical direction. The method of claim 6, A method of repairing a transverse electric field type liquid crystal display device, characterized in that it is cut using a laser cutting process and electrically contacted using a laser welding process.

Images