KR20050063006A - In plane switching mode liquid crystal display device and method for fabricating thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal drive type liquid crystal display device capable of preventing light leakage and improving an aperture ratio, and a method of manufacturing the same. A gate line and a data line, a switching element formed at an intersection of the gate line and the data line, at least one pair of common and pixel electrodes for generating a horizontal electric field in the pixel area, and the gate line and a part thereof overlap The present invention provides a horizontal drive type liquid crystal display device including a gate signal blocking line connected to the common electrode, and a liquid crystal layer formed between the first substrate and the second substrate.

Description

Horizontal drive type liquid crystal display device and manufacturing method thereof {IN PLANE SWITCHING MODE LIQUID CRYSTAL DISPLAY DEVICE AND METHOD FOR FABRICATING THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal drive type liquid crystal display device, and more particularly, to a horizontal drive type liquid crystal display device capable of preventing light leakage occurring between a gate line and a common line and improving an aperture ratio, and a manufacturing method thereof.

Liquid crystal display devices are mainly used as flat panel display devices having high quality and low power. The liquid crystal display device is bonded so that the thin film transistor array substrate and the color filter substrate face each other at a uniform interval, and a liquid crystal layer is formed between the thin film transistor array substrate and the color filter substrate.

In the thin film transistor array substrate, pixels are arranged in a matrix form, and a thin film transistor, a pixel electrode, and a capacitor are formed in a unit pixel, and the color filter substrate is a common electrode and an actual color for applying an electric field to the liquid crystal layer together with the pixel electrode. An RGB color filter and a black matrix are implemented to implement the.

On the other hand, an alignment layer is formed on the opposite surface of the thin film transistor array substrate and the color filter substrate, and rubbing is performed so that the liquid crystal layer is arranged in a constant direction. In this case, the liquid crystal is rotated by dielectric anisotropy when an electric field is applied between the pixel electrode formed for each unit pixel of the thin film transistor array substrate and the common electrode formed on the front surface of the color filter substrate, thereby passing or blocking light per unit pixel. Characters or images are displayed. However, the above-described twisted nematic mode liquid crystal display device has a disadvantage in that the viewing angle is narrow.

Therefore, a horizontal drive type liquid crystal display (In Plane Switching mode LCD) that solves the viewing angle problem by aligning the liquid crystal molecules almost in the direction of the substrate has been actively studied in recent years.

FIG. 1 schematically illustrates a unit pixel of a general horizontal driving type liquid crystal display device. FIG. 1A is a plan view, and FIG. 1B is a sectional view taken along line II ′ of FIG. 1A.

As shown in the figure, the gate line 1 and the data line 3 are vertically and horizontally arranged on the transparent first substrate 10 to define a pixel area. In an actual liquid crystal display device, n gate lines 1 and m data lines 3 intersect with n x m pixels, but only one pixel is shown in the figure for simplicity.

A thin film transistor 9 composed of a gate electrode 1a, a semiconductor layer 5, and source / drain electrodes 2a and 2b is disposed at an intersection point of the gate line 1 and the data line 3. The gate electrode 1a and the source / drain electrodes 2a and 2b are connected to the gate line 1 and the data line 3, respectively. In addition, the gate insulating film 8 is laminated over the entire substrate.

The common line 4 is arranged in parallel with the gate line 1 in the pixel area, and at least one pair of electrodes for switching the liquid crystal molecules, that is, the common electrode 6 and the pixel electrode 7 are parallel with the data line. Are arranged. The common electrode 6 is formed at the same time as the gate line 1 and connected to the common line 4, and the pixel electrode 7 is formed at the same time as the source / drain electrodes 2a and 2b to form the thin film transistor 9. It is connected to the drain electrode 2b. A protective film 11 is formed over the entire substrate including the source / drain electrodes 2a and 2b. In addition, the pixel electrode line 14 overlapping with the common line 4 and connected to the pixel electrode 7 forms the storage capacitor Cst with an insulating film 8 interposed therebetween. .

In addition, the second substrate 20 includes a black matrix 21 for preventing light leakage into the thin film transistor 9, the gate line 1, and the data line 3, and a color filter 23 for realizing color. The overcoat film 25 for planarizing the color filter 23 is apply | coated on it. On the opposing surfaces of the first substrate 10 and the second substrate 20, alignment films 12a and 12b for determining the initial alignment direction of the liquid crystal are coated.

In addition, a liquid crystal layer 13 is formed between the first substrate 10 and the second substrate 20 to control light transmittance by a voltage applied to the common electrode 6 and the pixel electrode 7. have.

The conventional horizontal drive type liquid crystal display device having the structure as described above has the advantage of improving the viewing angle because the common electrode 6 and the pixel electrode 7 are arranged on the same plane to generate a transverse electric field.

On the other hand, since the common electrode 6 and the pixel electrode 7 are disposed in the pixel area where the screen is displayed, there is a problem that the aperture ratio is lowered and the luminance is lowered.

In addition, since a horizontal electric field is not normally formed in the pixel due to signal interference between the data line 3 and the pixel electrode 7, the common electrode 6 is disposed in an area adjacent to the data line 3 to solve this problem. Arrangement prevents signal interference of the data line 3, and common line 4 is disposed in an area adjacent to the gate line 1, thereby preventing signal interference of the gate line 1. However, since the gate line 1 and the common line 4 are formed on the same plane, the gate line 1 and the common line 4 are spaced apart from each other by a predetermined distance to prevent their disconnection. Light leakage occurs in the spaced area A therebetween. That is, the liquid crystal disposed in this area A is driven by an electric field applied between the gate line 1 and the common line 4, and this driving is performed by the liquid crystal driving between the common electrode 6 and the pixel electrode 7. Because of the different direction and light leakage occurs.

Therefore, when the black matrix 21 is formed on the upper substrate 20 to cover the light leakage phenomenon, considering the bonding margin of the lower substrate 10 and the upper substrate 20, the black to the separation area (A) Since the matrix 21 must be formed, a problem arises in that the aperture ratio decreases due to the area occupied by the black matrix 21.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to form a common electrode and a pixel electrode made of a transparent conductive material, thereby improving the aperture ratio of the liquid crystal display device and a manufacturing method thereof To provide.

Another object of the present invention is to provide a liquid crystal display device and a method of manufacturing the same, which may further improve the aperture ratio by forming a gate signal blocking line adjacent to the gate line overlapping with the gate line.

Other objects and features of the present invention will be described in detail in the configuration and claims of the following invention.

The present invention for achieving the above object is a first and second substrate, a plurality of gate lines and data lines arranged vertically and horizontally on the first substrate to define a pixel region, and the intersection region of the gate line and the data line At least one pair of common and pixel electrodes for generating a horizontal electric field in the pixel region, a gate signal blocking line overlapping the gate line, and a part of the gate electrode, and the first electrode; It comprises a liquid crystal layer formed between the substrate and the second substrate.

A common signal transmission line adjacent to the data line is further configured, and the common signal transmission line is electrically connected to the common electrode to transfer a signal of the common line to the common electrode. In addition, the common electrode disposed on the common signal transmission line is to block the influence of the signal of the data line on the horizontal electric field generated between the common electrode and the pixel electrode.

In addition, the common electrode and the pixel electrode may have a bent structure, and the data line may be formed in the same bent structure as the common electrode and the pixel electrode.

In addition, a common line connected to the common electrode and the common signal transmission line is further formed, and a storage electrode connected to the pixel electrode is formed thereon to form a storage capacitor.

In addition, in the present invention, the common electrode and the pixel electrode are formed on the same plane, and both of them are made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

The horizontal drive type liquid crystal display device of the present invention configured as described above has an advantage that the aperture ratio can be improved compared to the prior art because the pixel electrode and the common electrode are formed of a transparent material. In addition, since they are formed on the same plane, the intensity of the electric field may be increased to increase the switching speed of the liquid crystal, and thus, the moving image may be easily implemented. That is, although the common electrode and the pixel electrode are conventionally formed on the same substrate, a weak electric field is generated compared to the present invention because an electric field is formed between the intervening layer, that is, the gate insulating film.

In addition, the gate signal blocking line for blocking the gate signal is formed on a different layer from the gate line, and the gate signal blocking line is formed to overlap each other, thereby preventing light leakage between the gate line and the gate signal blocking line. That is, conventionally, since the common line having the function of the gate signal blocking line of the present invention is formed on the same layer as the gate line, light leakage occurs in the spaced area therebetween. However, in the present invention, the gate line and the gate signal blocking line are formed to overlap each other, thereby preventing light leakage between the gap between the conventional gate line and the common line.

In addition, the method of manufacturing a horizontal drive type liquid crystal display device according to the present invention comprises the steps of providing a first and a second substrate, a plurality of gate lines on the first substrate, a common line parallel to the gate line, Forming a common signal transmission line, forming a data line vertically intersecting the gate line to define a pixel region, and forming a storage electrode overlapping the common line to form a storage capacitor; Forming a common electrode and a pixel electrode for generating a horizontal electric field, a gate signal blocking line connected to the common electrode and partially overlapping a front gate line, and forming a liquid crystal layer between the first and second substrates; A step is made.

In this case, the method may further include forming a passivation layer on the entire surface of the first substrate including the data line and the storage electrode. The common electrode, the pixel electrode, and the gate signal blocking line may be formed on the passivation layer. As described in the configuration, the common electrode and the pixel electrode are formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

Hereinafter, the horizontal drive type liquid crystal display device according to the present invention will be described in more detail with reference to the accompanying drawings.

2A and 2B illustrate a horizontal drive type liquid crystal display device according to the present invention. FIG. 2A is a plan view, and FIG. 2B is a cross section taken along the line II-II ′ of FIG. 2A.

As shown in the figure, the horizontal drive type liquid crystal display device 100 according to the present invention has a pixel area formed by a gate line 101 and a data line 103 arranged vertically and horizontally on a transparent first substrate 110. The switching element 109 is formed at the intersection of the gate line 101 and the data line 103. In addition, the switching element 109 may include a gate electrode formed as a part of the gate line 101, a semiconductor layer 105 formed on the gate electrode, and a source / drain electrode disposed on the semiconductor layer 105 at a predetermined interval. 102a, 102b).

In the pixel, at least one pair of common electrode 106 and pixel electrode 107 for generating a horizontal electric field are formed. A common line 104 is formed to be electrically connected to the common electrode 106 to apply a common signal. The storage electrode is connected to the drain electrode 102b of the thin film transistor 109 on the common line 104. 114 is formed. In addition, the storage electrode 114 is electrically connected to the pixel electrode 107 through the first contact hole 107a, which is connected to the pixel electrode 107 with the common line 104 interposed therebetween, and the storage capacitor ( Cst).

In addition, a common signal transmission line 102 is formed in an area adjacent to the data line 103 to be connected to the common electrode 106 through a second contact hole 106a to transmit a common signal. The common electrode 106 formed on the line 102 serves to block the data signal.

The common electrode 106 and the pixel electrode 107 may be formed in a bent structure such as a stripe structure or a zigzag structure. However, when the common electrode 106 and the pixel electrode 107 are in a bent structure, they may be formed in one pixel. Multi-domains in which the driving directions of the liquid crystals are symmetrical to each other are formed, and the advantages of minimizing color shift can be minimized by canceling the abnormal light due to the birefringence characteristics of the liquid crystals. have. In addition, the structure of the data line 103 may be formed in a bent structure having the same shape as the common electrode 106 and the pixel electrode 107.

A gate signal blocking line 115 for blocking a gate signal is formed in an area adjacent to the gate line 101, and the gate signal blocking line 115 is formed by overlapping a portion of the gate line 101. This is to prevent light leakage (see FIG. 1) generated in the spaced area A between the conventional gate line 1 and the common line 4. The conventional common line 1 is a gate signal blocking line of the present invention. 115) Corresponds.

As shown in the cross-sectional view of FIG. 2B, the gate line 101, the common signal transfer line 102, and the common line 104 are formed on the first substrate 110, and the gate insulating film 108 is formed on the upper surface thereof. Is applied. A data line 103 orthogonal to the gate line 101 is formed on the gate insulating layer 108, and although not shown in detail, the storage electrode 114 connected to the drain electrode 102b is also formed on the gate insulating layer 108. It is formed on the top. At this time, the common line 106 and the storage electrode 114 formed thereon form a storage capacitor Cst with the gate insulating layer 108 interposed therebetween (see FIG. 2A). The passivation layer 111 is coated on the entire surface of the first substrate 110 including the data line 103 and the storage electrode 114, and a common electrode 106 and a pixel electrode 107 are formed thereon. have. The common electrode 106 adjacent to the data line 103 is electrically connected to the common signal transmission line 102 and the second contact hole 106a formed thereunder.

On the other hand, the second substrate 120 is formed with a black matrix 121 to prevent light leakage and a color filter 123 for implementing the color. The first and second alignment layers 112a and 112b for determining the initial alignment direction of the liquid crystal are coated on opposite surfaces of the first substrate 110 and the second substrate 120, and the liquid crystal layer 113 is disposed therebetween. ) Is formed.

In the horizontal drive type liquid crystal display device 100 according to the present invention configured as described above, since the gate signal blocking line 115 is formed to be overlapped with the gate line 101, light leakage generated between them can be blocked. In addition, since light leakage does not occur in this region, the area of the black matrix 121 formed on the second substrate 120 can be reduced, and thus the aperture ratio can be improved as compared with the related art. This is achieved by forming the gate line 101 and the gate signal blocking line 115 on different layers, wherein the gate line 101 is formed on the gate insulating film 108, and the gate signal blocking line 115 is formed. It is formed on the protective film 111, and these can be formed so that they may overlap each other. The aperture ratio improvement effect of the present invention will be described in more detail in comparison with the prior art. First, since the gate line 1 is conventionally formed on the same layer as the common line 4, there is a spaced area A therebetween. Done. The common line 4 is electrically connected to the common electrode 6 to apply a common signal, and a common electrode 6 and a pixel in which the gate signal applied to the gate line 1 is adjacent to the gate line 1. It serves to block the influence on the edge region of the electrode (7). Therefore, the conventional common line 4 can be considered to correspond to the gate signal blocking line 115 of the present invention. In the conventional horizontal field type liquid crystal display device configured as described above, the liquid crystal is abnormally driven in the separation area A between the gate line 1 and the gate signal blocking line, that is, the common line 4, as described in the related art. Because of this, light leakage occurs. As a result, the black matrix 21 covering the light leakage region is formed up to the common line 4. As the black matrix 21 extends to the common line 4, the aperture ratio decreases.

On the other hand, in the present invention, by forming the gate signal blocking line 115 adjacent to the gate line 101 overlapping with the gate line 101, light leakage is blocked to minimize the area where the black matrix 121 is formed.

Furthermore, in the present invention, since the common electrode 106 and the pixel electrode 107 are formed on the same plane, that is, the protective film 111, the electric field applied to the liquid crystal layer 113 between the two electrodes is formed more strongly than in the prior art. do. Since the liquid crystal molecules in the liquid crystal layer 113 are switched at a higher speed by such a strong electric field, it is easy to implement a moving image.

In addition, since the common electrode 106 and the pixel electrode 107 are formed of a transparent conductive material, luminance can be improved by increasing the aperture ratio.

The horizontal drive type liquid crystal display device configured as described above is manufactured through the following process.

3A to 3C and FIGS. 4A to 4D illustrate the manufacturing of a horizontal drive type liquid crystal display device according to the present invention, in which a ground electrode and a pixel electrode are formed on the same plane, and a gate signal blocking line overlaps with the gate line. Process flowchart showing the method. Here, the process sectional drawing of FIGS. 3A-3C and the process plan view of FIGS. 4A-4D are shown together for the understanding of description.

First, as shown in FIGS. 3A and 4A, a transparent insulating substrate 210 such as glass is prepared, and then a metal such as Cu, Ti, Cr, Al, Mo, Ta, Al alloy is sputtered thereon. After the deposition, the patterned pattern is used to form a common signal transfer line 202 and a common line 204 connected to the common signal transfer line 202 disposed in a direction perpendicular to the gate line 201 and the gate line 201. Form.

Next, as illustrated in FIGS. 3B and 4B, SiNx or SiOx or the like is deposited on the entire surface of the substrate 210 including the gate line 201 and the common signal transfer line 202 by a plasma CVD method to form a gate insulating film. After forming 208, the semiconductor layer 205 is formed on the gate line 201 by laminating and patterning amorphous silicon and n + amorphous silicon on the gate insulating film 208. Then, a metal such as Cu, Mo, Ta, Al, Cr, Ti, and Al alloy is deposited on the substrate including the semiconductor layer through a sputtering method, and then patterned to cross the gate line 201 perpendicularly to the pixel. A storage electrode 214 and a source / drain electrode of a thin film transistor defining a region, a data line 203 adjacent to the common signal transmission line 202, and a storage capacitor overlapping the common line 204 to form a storage capacitor. 202a / 202b are formed, respectively.

Next, as shown in FIGS. 3C and 4C, the passivation layer 211 is formed over the entire surface of the substrate on which the data line 203 and the storage electrode 214 are formed, and then a portion thereof is removed to remove the story electrode 214. The second contact hole 206a exposing the first contact hole 207a and the common signal transmission line 202 are formed.

Subsequently, a common conductive layer 206 and a pixel electrode are deposited on the passivation layer 211 to form a horizontal electric field in the pixel region by depositing a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (ITO). 207 is formed. In this case, the common electrode 206 and the pixel electrode 207 may be formed in a zigzag curved structure for the multi-domain effect. In this case, the pixel electrode 207 is electrically connected to the storage electrode 214 through the first contact hole 207a, and the common electrode 206 is connected to the common signal transfer line 202 through the second contact hole 206a. And a common line 204. In addition, a gate signal blocking line 215 overlapping the gate line 201 adjacent to the edge region of the common electrode 206 and the pixel electrode 207 is also formed. The gate signal blocking line 215 is formed to block the influence of the signal of the gate line 201 on the edge regions of the common electrode 206 and the pixel electrode 207 adjacent to the gate line 201. In the present invention, the opening ratio of the region is improved by overlapping with the gate line 201.

Meanwhile, as shown in FIG. 4D, the liquid crystal display device is completed by bonding the second substrate 220 having the color filter layer 223 and the black matrix 221 to the second substrate 220. In this case, the black matrix 221 formed at a position corresponding to the gate signal blocking line 215 has an area corresponding to the width of the gate line 201 because the gate signal blocking line 215 overlaps the gate line 201. And the bonding margin of the first and second substrates 210 and 220.

As described above, the present invention can prevent the light leakage between the gate line and the gate signal blocking line by forming a gate signal blocking line for blocking the gate signal in a layer different from the gate line and overlapping each other. That is, conventionally, since the common line having the function of the gate signal blocking line of the present invention is formed on the same layer as the gate line, light leakage occurs in the spaced area therebetween. However, in the present invention, the gate line and the gate signal blocking line are formed to overlap each other, thereby preventing light leakage between the gap between the conventional gate line and the common line.

As described above, according to the present invention, in the horizontal drive type liquid crystal display device, a gate signal blocking line connected to the common electrode is formed on a different layer from the gate line, and the overlapping is performed between the common electrode and the gate signal blocking line. The image quality can be improved by preventing light leakage.

In addition, as the light leakage region is removed, the formation area of the black matrix is reduced, thereby improving the aperture ratio and consequently improving the brightness of the screen.

1A and 1B illustrate a general horizontal drive type liquid crystal display device.

2A and 2B illustrate a horizontal drive type liquid crystal display device according to the present invention;

3A to 3C are cross-sectional views illustrating a manufacturing process of a horizontal drive liquid crystal display device according to the present invention.

4A to 4D are process plan views showing the manufacturing process of the horizontal drive type liquid crystal display device according to the present invention;

*** Explanation of symbols for main parts of drawing ***

101,201: gate line 103,203: data line

104, 204: common line 106, 206: common electrode

107,207: pixel electrode 114,214: storage electrode

113,213: liquid crystal layer 121,221: black matrix

108,208: gate insulating film 111,211: protective film

102, 202: common signal transmission line

115,215: gate signal blocking line

Claims (15)

First and second substrates; A plurality of gate lines and data lines arranged vertically and horizontally on the first substrate to define pixel areas; A switching element formed at an intersection of the gate line and the data line; At least one pair of common electrode and pixel electrode for generating a horizontal electric field in the pixel region; A gate signal blocking line overlapping the gate line and a portion thereof and connected to the common electrode: and And a liquid crystal layer formed between the first substrate and the second substrate. The horizontal drive type liquid crystal display of claim 1, further comprising a common signal transmission line adjacent to the data line. The horizontal drive type liquid crystal display of claim 2, wherein the common signal transmission line is electrically connected to a common electrode. The horizontal drive type liquid crystal display device of claim 1, wherein the common electrode and the pixel electrode have a bending structure. The horizontal drive type liquid crystal display device of claim 1, wherein the data line has a curved structure. The horizontal drive type liquid crystal display of claim 1, further comprising a common line connected to the common electrode and the common signal transmission line. The horizontal drive type liquid crystal display device according to claim 1, further comprising a storage electrode connected to the pixel electrode and overlapping a common line to form a storage capacitor. The horizontal drive type liquid crystal display device of claim 1, wherein the common electrode and the pixel electrode are formed on the same plane. The method of claim 1, wherein the switching device, A gate electrode connected to the gate line; A gate insulating film formed on the gate electrode; A semiconductor layer formed on the gate insulating film; And a source electrode and a drain electrode formed on the semiconductor layer. The method of claim 1, The second substrate is a horizontal drive type liquid crystal display device comprising a color filter and a black matrix. Providing first and second substrates; Forming a plurality of gate lines, a common line parallel to the gate line, and a common signal transfer line on the first substrate; Forming a data line crossing the gate line to define a pixel area and a storage electrode overlapping the common line to form a storage capacitor; Forming a common electrode and a pixel electrode to generate a horizontal electric field in the pixel region, and a gate signal blocking line connected to the common electrode and partially overlapping a front gate line; And And forming a liquid crystal layer between the first and second substrates. 12. The method of claim 11, further comprising forming a passivation layer on an entire surface of the first substrate including the data line and the storage electrode. The method of claim 12, wherein the common electrode, the pixel electrode, and the gate signal blocking line are formed on a passivation layer. 12. The method of claim 11, wherein the common electrode and the pixel electrode are formed of a transparent conductive material. 12. The method of claim 11, wherein the transparent conductive material is made of indium tin oxide (ITO) or indium zinc oxide (IZO).