KR0182051B1 - Matrix type display device having repair structure repairable by pixel unit - Google Patents

Abstract

The present invention relates to a matrix display device having a mathematical structure, and more particularly, to a matrix display device that can be repaired in units of pixels. In the present invention, the gate electrode of the thin film transistor is formed to protrude separately from the branch of the gate line, and the intersection point of the data line and the upper gate line is a certain distance from the branch point of the gate electrode and the branch point of the source electrode. By doing so, it is possible to repair the short circuit by cutting the upper gate line without damaging the data line or the source electrode.

Description

Matrix display with repairable repair structure in units of pixels

1 is an equivalent circuit diagram showing a pixel portion of a conventional liquid crystal display device,

2 is a layout view of a thin film transistor substrate for a conventional liquid crystal display device,

3 is a layout view illustrating a method of arranging and repairing a thin film transistor substrate for a liquid crystal display according to an exemplary embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

1, 1a, 1b: auxiliary gate line 2: gate electrode

5 semiconductor layer 7 source electrode

8 drain electrode 10 pixel electrode

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a matrix type display device having a mathematical structure, and more particularly, to a matrix display device that can be repaired in units of pixels.

As a display device for human and computer media, a liquid crystal display (LCD), a plasma display panel (PDP), which replaces a conventional cathode ray tube (CRT), There are various flat panel displays (FPD) such as EL (electroluminescence) and FED (field emission display).

The liquid crystal display is one of the most popular flat panel displays in recent years, and is a display device using an electro-optical effect of a liquid crystal material, and its driving method is largely a simple matrix type and an active matrix. It is divided into active matrix types.

In an active matrix liquid crystal display, an operation of each pixel is controlled by adding a switching element having a nonlinear characteristic to each pixel arranged in a matrix form. That is, a three-terminal thin film transistor (TFT) is generally used as the switching element, and a thin film diode (TFD) such as a two-terminal metal insulator metal (MIM) is also used.

In particular, a liquid crystal display device using a thin film transistor as a switching element includes a thin film transistor and a pixel electrode, a gate line for supplying a scan signal or an open / close signal to pixels, and a data line for supplying an image signal. A thin film transistor substrate having lines formed thereon, an opposing substrate having common electrodes formed thereon, and a liquid crystal material enclosed therebetween.

Next, the structure of the pixel of the thin film transistor liquid crystal display will be described with reference to FIG. 1.

FIG. 1 is a diagram illustrating a structure and an equivalent circuit of a pixel of a liquid crystal display, wherein each pixel PX is a thin film transistor TFT formed on a lower substrate (a thin film transistor substrate) and a pixel electrode of a lower substrate. And a liquid crystal capacitor C _lc composed of a common electrode CE of the upper substrate as a counter substrate 10 and a liquid crystal material therebetween, and a storage capacitor C _st formed on the lower substrate. Doing. Here, the storage capacitor C _st serves to hold a signal applied to the pixel PX for a predetermined time. On the other hand, the pixel PX is connected to the data line and the gate line through the thin film transistor TFT. For example, one terminal of the thin film transistor TFT is connected to the data line, the other terminal is connected to the gate line, and the last terminal is connected to the pixel electrode 10.

In the liquid crystal display, when a pixel is driven and a display operation is performed, a predetermined voltage or a periodic voltage is applied to the common electrode CE, and a voltage is applied to the pixel electrode 10 through the thin film transistor TFT. The display operation is performed by the electro-optic effect of the liquid crystal material of the capacitor C _lc .

Next, the planar layout of the thin film transistor substrate corresponding to the lower substrate in the liquid crystal display having the structure shown in FIG. 1 will be described with reference to FIG. 2.

FIG. 2 is a plan view showing the layout of the thin film transistor substrate corresponding to the lower substrate in FIG. 1, and has a closed curve in which the structure of the gate line surrounds the pixel electrode. Here, PXi (i = 1, 2, 3, 4), which represents a rectangular region, is a region corresponding to the lower part of one pixel, but for convenience, it may include pixels including gate lines and data lines for convenience. The pixel area is referred to as a pixel region, and a set of pixels formed on a horizontal line is referred to as a pixel row.

As shown in FIG. 2, upper and lower gate lines G _up and G _down are formed on both sides of the pixel row on the transparent insulating substrate 100. The lower gate line (G _down) may beoteo soon properly horizontally, directed down from the upper gate line (G _up) has a first horizontal portion (G _h1), the first lateral portion (G _h1), which account for most of the length The second vertical part G _v1 , the second vertical part G _h1 , which goes up horizontally from the first vertical part G _v1 , and the second vertical part G _{v2 that} rises upward from the second horizontal part G _h2 . ) Is formed as one repeating unit. The double gate line structure is generally referred to as a double gate line structure.

A second vertical portion of the upper gate line a first horizontal portion (G _h1) and the lower gate line (G _down) is connected to the left auxiliary gate line (1a), an upper gate line (G _up) of (G _up) ( G _v2 ) extends downward to form a right auxiliary gate line 1b that meets the lower gate line G _down .

A data line D is vertically formed between each pixel column, and intersects the first horizontal portion G _h1 and the lower gate line G _down of the upper gate line G _up via the gate insulating side.

The upper and lower gate lines G _up and G _down and the pair of auxiliary gate lines 1a and 1b formed to the left and the right serve as a closed loop black matrix, which is defined as the closed curve. The pixel electrode 10 to overlap the gate lines G _up and G _down and the auxiliary gate lines 1a and 1b with a gate insulating layer (not shown) and a protective film (not shown) interposed therebetween. Is formed, and the overlapped portion serves as a holding capacitor (C _st in FIG. 1). This holding capacitor is also called a ring capacitor because it consists of a closed curve, and only the upper and lower gate lines G _up and G _down and the pair of auxiliary gate lines 1a and 1b constituting the ring capacitor are used. It is weak and is also called a ring capacitor. Here, the ring capacitor is used in the latter sense.

Thus, when the gate lines G _up and G _down and the auxiliary gate lines 1a and 1b have a structure surrounding the pixel electrode 10 in the form of a closed curve, the gate lines G _up and G _down and the auxiliary gate lines It is advantageous to adopt such a structure because no signal is cut off if any part of (1a, 1b) is disconnected.

Meanwhile, a thin film transistor is formed in the second vertical portion G _v2 of the upper gate line G _up , which will be described in detail.

First, part of the second vertical part G _v2 becomes a gate electrode 2 of the thin film transistor. When the material forming the gate lines G _up and G _down is an anodizable material such as aluminum, except for a gate pad (not shown) that electrically connects the gate lines G _up and G _down to the outside. The remainder is usually anodized. Therefore, an anodized gate oxide film (not shown) also exists on the gate electrode 2.

A gate insulating layer (not shown) is formed on the entire surface of the gate oxide film except for the gate pads.

The semiconductor layer 5 is formed to cover the gate electrode 2 with the gate insulating layer interposed therebetween. A semiconductor layer 5, in addition to covering the gate electrodes 2 are formed also on the gate lines (G _up, G _down) and serves to prevent short-circuiting of the gate line (G _up, G _down) and the data line (D). The material constituting the semiconductor layer 5 is generally amorphous silicon or polycrystalline silicon.

On the semiconductor layer 5 is formed a contact layer (not shown) for good ohmic contact between the semiconductor and the metal, which is mainly n ⁺ amorphous, which is heavily doped. It is made of silicon. In FIG. 2, the pattern of the contact layer becomes a portion where the semiconductor layer 5 and the source electrode 7 and the drain electrode 8 overlap each other.

On the contact layer, a source electrode 7 which is a branch of the data line D and a drain electrode 8 separated therefrom are formed. Since the source electrode 7 is located near the intersection of the upper gate line G _up and the data line D, the source electrode 7 overlaps with the first horizontal portion G _v2 of the upper gate line G _up as shown in FIG. 2. There may be. One end of the drain electrode 8 faces the source electrode 7 with the gate electrode 2 interposed therebetween, and the other end is connected to the pixel electrode 10 of the upper pixel of the same pixel column and has a lower gate line. Overlaid with (G _down ). For example, in FIG. 2, the drain electrode 8 of the pixel PX2 is connected to the pixel electrode 10 of the pixel PX1, which is the upper pixel of the same pixel column, and the pixel electrode 10 of the pixel PX1. It overlaps with the lower gate line G _down positioned below.

A protective film (not shown) is covered over the drain electrode 8 and the pixel electrode 10 except for contact portions and pads (not shown), and a pixel electrode 10 made of a transparent conductive material is formed on the protective film. It is.

In the pixel structure as shown in FIG. 2, a thin film transistor (including a gate electrode, a source electrode, and a drain electrode) formed in a pixel region does not drive the pixel, but for convenience of explanation throughout the present specification, This is called a thin film transistor (gate electrode, source electrode, drain electrode) of the pixel.

As described above, a thin film transistor substrate for a flat panel display device, particularly a liquid crystal display device, has wirings such as gate lines and data lines for supplying signals to the pixels. However, it is easy to break or short-circuit in the manufacturing process such as the subsequent heat treatment process and etching process. In particular, a short circuit is likely to occur at the intersection of the gate line and the data line. When the wiring is disconnected, a signal necessary for the pixel cannot be properly applied, and thus, the display device cannot be properly performed.

Meanwhile, in the case of the liquid crystal display having the gate lines G _up , G _down, 1a, and 1b as shown in FIG. 2, the upper and lower gate lines G _up and G _down and the data line D once each. If the intersection (x, y) is a short circuit between the lower gate line G _down and the data line D, the lower gate line G _{down on} both sides of the shorting point x is cut out. In the case where the upper gate line G _up and the data line D are short-circuited, the upper gate line G _up of both short-circuit points y is cut off to isolate the thin film transistor and drain electrodes of the thin film transistor. There is a problem that a data signal is always applied to the pixel electrode 10 connected to (8) so that a voltage is always applied. In particular, when there is only one such pixel, there is no problem, but when such a defect occurs in various places, the entire liquid crystal display is defective.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object thereof is to enable repair of short circuits between a gate line and a data line.

The matrix display device according to the present invention is a matrix display device in which a plurality of pixel regions are formed in the form of a matrix. The matrix display device includes upper gate lines and horizontally formed upper and lower boundaries of each pixel region. A data line formed vertically between and insulated from and intersecting the upper and lower gate lines, a pixel electrode formed in the pixel region and made of a transparent conductive material, and a gate electrode connected to the upper gate line and a source electrode connected to the data line And a transistor having a drain electrode connected to the pixel electrode, wherein an intersection point of the data line and the upper gate line is planarly separated from a connection point of the source electrode and the data line.

Here, the gate electrode is preferably a branch of the upper gate line, and particularly preferably parallel to the data line.

The gate line is bent outward near the intersection of the data line and the upper gate line, so that the empty space near the intersection point does not damage the data line when cutting the upper gate line later.

The auxiliary gate line may further include an auxiliary gate line forming a boundary of each pixel area, and the auxiliary gate line may connect the upper and lower gate lines to each other.

In such a matrix type display device, a method for repairing a defect due to a short circuit between a gate line and a data line includes cutting a gate line to the left and right of the intersection when the intersection point of the gate line and the data line is shorted. That is, since the intersection of the data line and the upper gate line is separated from the connection point of the source electrode and the data line in a plane, the short circuit can be repaired by cutting the upper gate line without damaging the data line or the source electrode.

Next, embodiments of the matrix display device according to the present invention will be described in detail below with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention.

First, in the embodiment of the present invention, the gate electrode of the thin film transistor is formed to protrude separately into the branch of the gate line, and the intersection point of the data line and the upper gate line is a certain distance from the branch point of the gate electrode and the branch point of the source electrode. I put it.

This embodiment will be described in detail with reference to FIG.

In FIG. 3, the second horizontal portion G _h2 of the upper gate line G _up intersects the data line D, and the second vertical portion G _v2 is located on the right side of the data line D. FIG. The gate electrode 2 is a branch which protrudes upward from the second horizontal portion G _h2 , and the intersection of the data line D and the upper gate line G _up is a branch point of the gate electrode 2. And a distance from the branching point of the source electrode is different from the conventional structure shown in FIG.

In this case, even if a short circuit occurs between the upper gate line G _up and the data line D, the thin film transistors are not isolated when the upper gate lines G _{up on the} left and right sides of the intersection y are cut (a, b). Repair of the gate lines G _up and G _down is possible.

On the other hand, when cutting the upper gate line G _up here, a certain amount of space is required to prevent damage to the data line D. FIG. To this end, the gate lines G _up , G _down, 1a, and 1b near the intersection y of the upper gate line G _up and the data line D are bent toward the outside of the intersection y. .

Further, by cutting the gate electrode (2) even if the advent of defects in the thin film transistor due to the gate electrode 2 of the TFT this is not part of the upper gate line (G _up) spun from the upper gate line (G _up) branched When the upper gate line G _up is separated from the upper gate line G _up , it is easily repaired without cutting the upper gate line G _up .

As described above, in the present invention, it is possible to efficiently repair defects caused by short-circuits of the gate lines and data lines and to repair defects of the thin film transistors without increasing the number of processes or decreasing the aperture ratio.

Claims (7)

A matrix type display device in which a plurality of pixel regions are formed in a matrix form, wherein the upper and lower gate lines are formed vertically along the upper and lower boundaries of each pixel region, and are vertically formed between the pixel regions. A data line insulated from and intersecting the upper and lower gate lines, a pixel electrode formed in the pixel region, and made of a transparent conductive material, a gate electrode connected to the upper gate line, and a source electrode connected to the data line; And a transistor having a drain electrode connected to a pixel electrode, wherein an intersection point of the data line and the upper gate line is planarly separated from a connection point of the source electrode and the data line. The matrix type display device of claim 1, wherein the gate electrode is a branch of the upper gate line. The matrix type display device of claim 1, wherein the gate electrode is parallel to the data line. 4. The matrix display device of claim 3, wherein the gate line is bent outward near an intersection point of the data line and the upper gate line so that an empty space near the intersection point is widened. The matrix display device of claim 1, further comprising an auxiliary gate line that forms a boundary of each pixel area. The matrix display device of claim 5, wherein the auxiliary gate line connects the upper and lower gate lines to each other. A repair method of a matrix display device in which a plurality of pixel regions are formed in a matrix form, the upper and lower gate lines being formed horizontally while forming upper and lower boundaries of each pixel region, and connected to the upper gate line. Forming a gate electrode, an insulating layer covering the gate line and the gate electrode, a data line crossing the gate line vertically between each pixel region, and connected to the data line and the data line An intersection point of an upper gate line forms a source electrode which is planarly separated from a connection point of the source electrode and the data line, and a drain electrode facing the source electrode, and when the intersection point of the gate line and the data line is shorted, Cutting the gate line Repair method of the matrix display device.