KR101695025B1 - Liquid crystal display and method of repairing the same - Google Patents

Abstract

The present invention relates to a liquid crystal display device including an island pattern, including data lines and gate lines crossing each other; TFTs formed at intersections of the data lines and the gate lines; Pixel electrodes connected to the TFTs; And island patterns formed at intersections of the gate lines and the data lines. The island pattern overlaps with any one of the data lines.

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal display (LCD)

The present invention relates to a liquid crystal display device including an island pattern and a dot inversion control method thereof.

A liquid crystal display device of an active matrix driving type displays a moving picture by using a thin film transistor (hereinafter referred to as "TFT") as a switching element. The liquid crystal display device can be downsized as compared with a cathode ray tube (CRT), and is applied to a display device in a portable information device, an office machine, a computer, and the like, and is rapidly applied to a television, thereby quickly replacing a cathode ray tube. The liquid crystal display device forms a liquid crystal layer having anisotropic permittivity of upper and lower transparent substrates and changes the molecular arrangement of the liquid crystal material by adjusting the intensity of an electric field formed in the liquid crystal layer according to video data to display a desired image.

The manufacturing process of a liquid crystal display device includes the steps of cleaning a substrate of a liquid crystal display panel, patterning a substrate, forming / rubbing an alignment film, adhering a substrate and dropping a liquid crystal, mounting a drive circuit, inspecting, repairing, do.

The substrate cleaning process removes contaminants from the upper glass substrate and the lower glass substrate of the liquid crystal display panel with a cleaning liquid. The substrate patterning process includes the steps of forming and patterning various thin film materials such as signal lines, data lines, and gate lines, TFTs, and pixel electrodes on a lower glass substrate, and a step of forming a black matrix, a color filter, And forming and patterning various thin film materials. In the alignment film forming / rubbing process, an alignment film is applied on glass substrates and the alignment film is rubbed with a rubbing film or optically aligned. Through the series of processes, the lower glass substrate of the liquid crystal display panel is provided with data lines to which video data voltages are supplied, gate lines that intersect the data lines and are supplied with scan signals, that is, gate pulses sequentially, TFTs formed at intersections of the gate lines, TFTs arrays including pixel electrodes of liquid crystal cells connected to the TFTs at 1: 1, storage capacitors, and the like are formed. A color filter array including a black matrix, a color filter, and a common electrode is formed on the upper glass substrate of the liquid crystal display panel. The common electrode is formed on the upper glass substrate in a vertical electric field driving method such as a TN (Twisted Nematic) mode and a VA (Vertical Alignment) mode, and a horizontal electric field such as IPS (In Plane Switching) mode and FFS (Fringe Field Switching) Is formed on the lower glass substrate together with the pixel electrode in the driving method. A polarizing plate and a polarizing plate and a protective film are attached to the upper glass substrate and the lower glass substrate, respectively.

The substrate coalescence and liquid crystal dropping process draws a sealant on one of the upper and lower glass substrates of the liquid crystal display panel and drops the liquid crystal on another substrate.

In the driving circuit mounting process, an integrated circuit (IC) of a data driving circuit is mounted on a lower glass substrate of a liquid crystal display panel using a COG (Chip On Glass) process or a TAB (Tape Automated Bonding) process. The gate drive circuit IC may be formed directly on the lower glass substrate of the liquid crystal display panel together with the TFT array, or on the lower glass substrate in the TAB process in the driver circuit mounting process. The driving circuit mounting process connects the driving circuit ICs and the printed circuit board (PCB) with a flexible printed circuit board (FPC) or a flexible flat cable (FFC).

In such a manufacturing process, various defects such as disconnection or short circuit of the gate line or the data line, a TFT defect, a pixel electrode defect, or the like may occur. The defects can be divided into dot defects, line defects or display defects according to the shape. The point defect is mainly caused by defective TFT or pixel electrode.

The inspecting process includes inspections for driving circuit ICs, wiring inspections of data lines and gate lines formed on the TFT array substrate, inspections after the pixel electrodes are formed, electrical inspections after the liquid crystal dropping process, Lt; RTI ID = 0.0 > defects. ≪ / RTI > Redundant and repairable designs are applied to TFT array substrates as a way to actively cope with the occurrence of defects. As an example of the redundancy design, there is a method of disposing a plurality of TFTs in one pixel in place of TFTs determined to be defective, and when a gate line or a data line is disconnected; And a redundancy pattern for connecting the wirings is formed so as to overlap the gate line or the data line. When the degree of defect is severe and the number of defective pixels is equal to or greater than the reference value, the repairing process is not performed. When the number of defective pixels is within the reference value, the repairing process proceeds. The repair process repairs the defective or bad defects detected by the inspection process.

When the liquid crystal display panel completed through the above-described series of steps is completed, the assembling process of the liquid crystal module assembles the backlight unit under the liquid crystal display panel using the guide / case member.

In order to easily ignite the point defects, there is a method of applying a redundancy design of a double structure to each of the gate lines at the intersection with the data lines. In this case, the overlapping area of the gate metal including the gate line and the gate electrode of the TFT, the data line and the data metal including the source / drain electrodes of the TFT becomes large, and the gate-data parasitic capacitance Cgd becomes large. As a result, the increase of the data load and the aperture ratio are reduced due to the increase of the parasitic capacitance.

The present invention provides a liquid crystal display device and a repair method thereof which can easily make the point defect dark, reduce parasitic capacitance between gate and data, and increase the aperture ratio.

The liquid crystal display of the present invention includes data lines and gate lines crossing each other; TFTs formed at intersections of the data lines and the gate lines; Pixel electrodes connected to the TFTs; And island patterns formed at intersections of the gate lines and the data lines. The island pattern overlaps with any one of the data lines.

The repair method of the liquid crystal display device includes: forming island patterns at intersections of the gate lines and the data lines; Determining a point defect through an inspection process; Disconnecting a connection portion of the TFT and the gate line in the point defective pixel and a connection portion of the TFT and the pixel electrode in the point defective pixel; Forming metal patterns on both sides of the disconnection portion of the gate line overlapping both sides of the island pattern using a laser-CVD process; And connecting both sides of the disconnected portion of the gate line with both sides of the island pattern in a laser welding process.

The present invention can form an island pattern between a pair of neighboring gate lines between display lines, darken the point defect using the island pattern, and repair the disconnected gate lines. As a result, the present invention is easy to darken point defects, reduce the parasitic capacitance between gate and data, and increase the aperture ratio.

1 is an equivalent circuit diagram showing a part of a pixel array of a liquid crystal display according to an embodiment of the present invention.
FIG. 2 is a plan view showing in detail the intersection of the second data line and the fourth and fifth gate lines in FIG. 1; FIG.
3 is a sectional view of the TFT array substrate taken along the line "I-I" in Fig.
4 is a view showing a process of disconnecting the third TFT and the fourth gate line.
5 is a view showing a laser-CVD process for connecting the fourth gate line and the island pattern.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The liquid crystal display device of the present invention can be implemented in any form such as a transmissive liquid crystal display device, a transflective liquid crystal display device, and a reflective liquid crystal display device. In a transmissive liquid crystal display device and a transflective liquid crystal display device, a backlight unit is required. The backlight unit may be implemented as a direct type backlight unit or an edge type backlight unit. The liquid crystal mode applicable in the present invention may be a vertical field driving method such as TN (Twisted Nematic) mode and VA (Vertical Alignment) mode or a horizontal field driving method such as IPS (In-Plane Switching) mode and FFS (Fringe Field Switching) Mode, and all currently known liquid crystal modes are applicable.

In the liquid crystal display of the present invention, the liquid crystal display panel includes a TFT array substrate, a color filter array substrate, and a liquid crystal layer formed between the substrates. The liquid crystal display panel displays video data in a pixel array as shown in Fig.

1, a liquid crystal display according to the present invention includes a plurality of gate lines G1 to G8, a plurality of gate lines G1 to G8, a plurality of gate lines G1 to G8, And pixel electrodes PXL connected to the TFTs T1 to T4 in a 1: 1 relationship. A data driving circuit (not shown) converts the digital video data to a positive / negative gamma compensation voltage to generate a data voltage, and supplies the data voltage to the data lines D1 to D4. A gate driving circuit (not shown) sequentially supplies gate pulses (or scan pulses) to the gate lines G1 to G8. A pair of gate lines in which gate pulses are sequentially supplied are arranged between the display lines LINE # 1 to LINE # 4 of the pixel array. 1, "R" is a liquid crystal cell of a red subpixel for displaying red data, and "G" is a liquid crystal cell of a green subpixel for displaying green data. And "B" is a blue subpixel liquid crystal cell for displaying blue data. Liquid crystal cells neighboring to the left and right are connected to the same data line via the TFTs T1 to T4, and charge the data voltages sequentially supplied from the data line. Therefore, the present invention can reduce the number of necessary data lines and the data driving circuit at the same resolution as the pixel array structure in general.

Two liquid crystal cells arranged on the left and right sides of the first data line D1 in the first display line LINE # 1 are referred to as first and second liquid crystal cells and a second data line LINE # The liquid crystal cell arranged on the left side of the line D2 is defined as the third liquid crystal cell and the liquid crystal cell arranged on the right side of the second data line D2 on the third display line LINE # 3 is defined as the fourth liquid crystal cell The pixel array structure of the present invention will be described. The first TFT T1 supplies the data voltage from the first data line D1 to the pixel electrode PXL of the first liquid crystal cell in response to the first gate pulse from the first gate line G1. A gate electrode of the first TFT (T1) is connected to the first gate line (G1), and a drain electrode is connected to the first data line (D1). The source electrode of the first TFT (T1) is connected to the pixel electrode (PXL) of the first liquid crystal cell. A second gate pulse is generated subsequent to the first gate pulse to turn on the second TFT (T2). The second TFT T2 supplies the data voltage from the first data line D1 to the pixel electrode PXL of the second liquid crystal cell in response to the second gate pulse from the second gate line G2. The gate electrode of the second TFT T2 is connected to the second gate line G2, and the drain electrode thereof is connected to the first data line D1. And the source electrode of the second TFT T2 is connected to the pixel electrode PXL of the second liquid crystal cell. Accordingly, the first and second liquid crystal cells disposed on the left and right sides of the first data line D1 sequentially charge the data voltages supplied through the first data line D1.

The third TFT T3 supplies the data voltage from the second data line D2 to the pixel electrode of the third liquid crystal cell in response to the fourth gate pulse from the fourth gate line G4. The gate electrode of the third TFT T3 is connected to the fourth gate line G4, and the drain electrode thereof is connected to the second data line D2. And the source electrode of the third TFT T3 is connected to the pixel electrode of the third liquid crystal cell. The fifth gate pulse is generated subsequent to the fourth gate pulse to turn on the fourth TFT T4. The fourth TFT T4 supplies the data voltage from the second data line D2 to the pixel electrode of the fourth liquid crystal cell in response to the fifth gate pulse from the fifth gate line G5. The gate electrode of the fourth TFT T4 is connected to the fifth gate line G5, and the drain electrode thereof is connected to the second data line D2. The source electrode of the fourth TFT T4 is connected to the third liquid crystal cell arranged in the second display line LINE # 2 along the pixel electrode of the fourth liquid crystal cell and the third liquid crystal cell arranged in the third display line LINE # The fourth liquid crystal cell sequentially charges the data voltages supplied through the second data line D2.

The present invention applies the island pattern (ILP) as shown in Fig. 2 to the intersection of the data lines and the gate lines in order to facilitate the ignition of the point defect.

FIG. 2 is a plan view showing in detail the intersection of the second data line D2 and the fourth and fifth gate lines G4 and G5 in FIG. 3 is a sectional view of the TFT array substrate taken along the line "I-I" in Fig.

2 and 3, the TFT array substrate of the present invention includes a gate metal pattern formed on a substrate SUB, a gate insulating film GI covering the gate metal pattern, a semiconductor pattern formed on the gate insulating film, Metal pattern. The gate metal pattern is made of a metal such as any one of aluminum (Al), AlNd, and copper (Cu) or an alloy thereof. The gate electrode GE of the TFTs T3 and T4 and the gate electrode of the TFTs T3 and T4 Gate lines G4 and G5 connected to the gate line GE, an island pattern (ILP), and the like. A plurality of island patterns (ILP) are formed in the pixel array. The island pattern ILP is disposed between the pair of gate lines GL at the intersection of the data line D2 and the pair of gate lines GL. The island pattern ILP is an independent metal pattern electrically separated from the TFTs T3 and T4 and the gate lines G4 and G5. The line width of the island pattern ILP is smaller than the line width of each of the gate lines G3 and G4 and the data line D2 and overlaps with the data line D2.

The gate insulating film GI includes an insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx). The semiconductor pattern is made of a semiconductor material such as amorphous silicon or polysilicon and is formed on the gate insulating film GI. The semiconductor pattern includes an active layer (ACT) and an ohmic contact layer (OHM). The source-drain metal pattern is formed of a metal such as any one of copper (Cu), aluminum (Al), AlNd, and molybdenum (Mo) or an alloy thereof, and is formed on the ohmic contact layer (OHM). The source-drain metal pattern includes a drain electrode DE of the TFTs T3 and T4, a data line D2 connected to the drain electrode DE of the TFTs T3 and T4, a source electrode SE of the TFT, .

The TFT array substrate of the present invention includes a passivation film (PASSI) and a pixel electrode (PXL). The passivation film PASSI is an organic insulating material such as an inorganic insulating material such as a gate insulating film GI or an acrylic organic compound having a small dielectric constant, a benzocyclobutene (BCB) or a perfluorocyclobutane (PFCB) Is formed on almost all surfaces of the TFT array substrate so as to cover the pattern. The passivation film PASSI includes a contact hole CNTH exposing the source electrode SE of the TFTs T3 and T4.

The pixel electrode PXL may be formed of indium tin oxide (ITO), tin oxide (TO), indium tin zinc oxide (IZO), indium zinc oxide (IZO) (PASSI) including a transparent conductive material. The pixel electrode PXL is connected to the source electrode SE of the TFTs T3 and T4 through the contact hole CNTH.

Assuming that defects occur in the TFT (T3) or the pixel electrode (PXL) of the third liquid crystal cell in the inspection process, FIGS. 4 and 5 are combined to explain a method of igniting the third liquid crystal cell in the repair process .

4 is a view showing a process of disconnecting the third TFT T3 and the fourth gate line G4. 5 is a view showing a laser CVD (Chemical Vapor Deposition) process connecting the fourth gate line G4 and the island pattern ILP.

4 and 5, the repair process first irradiates the laser beam onto the first to second cutting lasers CUT1 to CUT3, disconnects the connection portion between the third TFT T3 and the fourth gate line GL, And the connecting portion of the third TFT T3 and the pixel electrode PXL is disconnected. The first and second cutting lines CUT1 and CUT1 are positioned on the fourth gate line G4 connected to both sides of the gate electrode GE of the third TFT T3. The third cutting line CUT3 is located on the source electrode SE of the third TFT T3. As a result, the gate electrode GE of the third TFT T3 and the fourth gate line G4 do not operate the third gate TFT T3. In addition, in the normally black mode in which the higher the data voltage is, the third TFT T3 and the pixel electrode PXL are electrically separated from each other, so that the third liquid crystal cell can emit light Which is not permeable to the ink.

Since the fourth gate line G4 is disconnected immediately after the laser disconnection process as shown in FIG. 4, the entire second display line LINE # 2 from the right side of the third liquid crystal cell in FIG. 1 may appear as a line defect. Therefore, the repair process of the present invention electrically connects the island pattern (ILP) to both sides of the disconnected portion of the fourth gate line G4 using the laser-CVD system as shown in FIG. In the laser-CVD system, a TFT array substrate is placed in a vacuum chamber, a laser beam is irradiated to the surface of the TFT array substrate, and a source gas is introduced. In this laser-CVD process, the laser beam can induce photodegradation of the source gas to form the first and second metal patterns CNT1 and CNT2 at the positions irradiated with the laser beam. The laser-CVD system can form the first and second metal patterns CNT1 and CNT2 with metals such as chromium (Cr), tungsten (W), and molybdenum (Mo). The first metal pattern CNT1 is deposited on the passivation layer PASSI such that one side of the disconnection portion of the fourth gate line G4 overlaps with one side of the island pattern ILP. The first metal pattern CNT1 is deposited on the protective film PASSI such that the other side of the disconnection portion of the fourth gate line G4 overlaps with the other side of the island pattern ILP.

Lastly, the repairing process is performed in such a manner that a laser beam is applied to a portion where the metal patterns CNT1, CNT2 and the fourth gate line G4 overlap each other and a portion where the metal patterns CNT1, CNT2 and the island pattern ILP overlap each other Investigate. As a result, the metal patterns CNT1 and CNT2 pass through the passivation film PASSI by laser welding, the metal patterns CNT1 and CNT2 are connected to the fourth gate line G4, (ILP). Thus, the broken line portion of the fourth gate line G4 is connected again to the metal patterns CNT1, CNT2 and the island pattern ILP.

As described above, the island pattern ILP has a smaller width than the line width of the gate line and is disposed between the pair of gate lines G4 and G5. The island pattern ILP may be connected to any of the pair of gate lines G4 and G5. Therefore, the present invention can repair two neighboring gate lines G4 and G5 with an island pattern (ILP) smaller than the line width of the gate line, so that the gate-to-data parasitic capacitance (Cgd) And the aperture ratio can be increased.

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.

ILP: island pattern D1 to D4: data line
G1 to G8: Gate lines T1 to T4: TFT
PXL: pixel electrode

Claims (10)

Data lines and gate lines crossing each other;
TFTs formed at intersections of the data lines and the gate lines;
Pixel electrodes connected to the TFTs; And
And island patterns formed at intersections of the gate lines and the data lines,
The gate lines,
A liquid crystal display device comprising first and second gate lines neighboring between display lines of a liquid crystal display device,
In the island pattern,
Wherein the first gate line and the second gate line are disposed between the first gate line and the second gate line at an intersection of any one of the data lines and the first and second gate lines. The method according to claim 1,
In the island pattern,
Wherein the data lines are overlapped with any one of the data lines. The method according to claim 1,
The TFTs,
A first TFT for supplying a data voltage from an ith (i is a natural number) data line to a first pixel electrode in response to a first gate pulse from the first gate line; And
And a second TFT for supplying a data voltage from the ith data line to the second pixel electrode in response to a second gate pulse from the second gate line. delete The method of claim 3,
Wherein a line width of the island pattern is smaller than a line width of each of the gate lines and the data lines and is overlapped with the i-th data line between the first and second TFTs. A method for repairing a liquid crystal display device including data lines and gate lines crossing each other, TFTs formed at intersections of the data lines and gate lines, and pixel electrodes connected to the TFTs,
Forming island patterns at intersections of the gate lines and the data lines;
Determining a point defect through an inspection process;
Disconnecting a connection portion of the TFT and the gate line in the point defective pixel and a connection portion of the TFT and the pixel electrode in the point defective pixel;
Forming metal patterns on both sides of the disconnection portion of the gate line overlapping both sides of the island pattern using a laser-CVD process; And
And connecting both sides of the disconnected portion of the gate line with both sides of the island pattern in a laser welding process,
The gate lines,
A liquid crystal display device comprising first and second gate lines neighboring between display lines of a liquid crystal display device,
In the island pattern,
Wherein the first and second gate lines are arranged between the first gate line and the second gate line at an intersection of any one of the data lines and the first and second gate lines. The method according to claim 6,
In the island pattern,
Wherein the data lines are overlapped with any one of the data lines. The method according to claim 6,
The TFTs,
A first TFT for supplying a data voltage from an ith (i is a natural number) data line to a first pixel electrode in response to a first gate pulse from the first gate line; And
And a second TFT for supplying a data voltage from the ith data line to the second pixel electrode in response to a second gate pulse from the second gate line. delete 9. The method of claim 8,
Wherein a line width of the island pattern is smaller than a line width of each of the gate lines and the data lines and is overlapped with the i-th data line between the first and second TFTs.

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