KR101203522B1 - In plane switching mode liquid crystal display device and method for fabricating thereof - Google Patents

Abstract

The present invention relates to a horizontal field type liquid crystal display device and a method for manufacturing the same, which can prevent the sealing material from bursting by using a black matrix of a metal material, comprising: a first substrate; A second substrate including a metal black matrix; A plurality of gate lines arranged in a first direction on the first substrate; A plurality of data lines arranged in a second direction perpendicular to the gate line to define a plurality of pixel regions together with the gate line; A protective film formed on an entire surface of the first substrate including the data line; A switching element formed at an intersection of the gate line and the data line; A common electrode and a pixel electrode formed in the pixel region to generate a horizontal electric field; And a liquid crystal layer formed between the first substrate and the second substrate, wherein the common electrode includes a first common electrode formed in a center region of the pixel region and a second common electrode formed in a region adjacent to the data line. The first common electrode is formed on the same layer as the gate line, while the second common electrode is formed together with the pixel electrode on the passivation layer, and the width of the second common electrode is greater than that of the first substrate and the second substrate. It is characterized in that it is larger than the cell gap between the substrates.

Black Matrix, Common Electrode, Sealing Material

Description

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

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

2 is a cross-sectional view of a liquid crystal panel in which a sealing material is formed.

3 is a plan view schematically showing a liquid crystal display device according to the present invention.

4A and 4B illustrate a liquid crystal display device according to the present invention. FIG. 4A is a plan view showing unit pixels of a thin film transistor array substrate, and FIG. 4B is a cross-sectional view taken along line II-II ′ of FIG. 4A.

5 is a view for explaining a viewing angle compensation principle.

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

101: gate line 103: data line

106, 106 ': common electrode 107: pixel electrode

113: liquid crystal layer 121: black matrix

123: color filter 128: auxiliary electrode

The present invention relates to a horizontal field type liquid crystal display device, and more particularly, to a horizontal field type liquid crystal display device and a method for manufacturing the same, which can prevent the sealing material from bursting by using a metal black matrix.

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 uniform intervals, 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 allowing light to pass through or blocked for each 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.

Accordingly, in-plane switching mode LCD (LCD), which solves a viewing angle problem by aligning liquid crystal molecules in a substantially horizontal direction with a substrate, has been actively studied in recent years.

FIG. 1 schematically illustrates a unit pixel of a general horizontal field type liquid crystal display device. FIG. 1A is a plan view, and FIG. 1B is a cross-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 the common line 4 and connected to the pixel electrode 7 forms an accumulation capacitor Cst with an insulating film 8 interposed therebetween. All.

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 field type liquid crystal display device having the structure as described above has the advantage of improving the viewing angle because the common electrodes 6a and 6b 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, the first and second substrates 10 and 20 are bonded to the sealing material formed on the outer side thereof, and as the size of the panel becomes smaller, such as a notebook, as shown in FIG. 2, the second substrate 20 The black matrix 21 formed on the outer surface overlaps the sealing material 19.

However, since the black matrix 21 is made of black resin, not only the adhesion to the second substrate 20 is weak, but also the black matrix 21 and the second substrate 20 are caused by frequent fluctuations of the substrate during liquid crystal injection. Lifting occurs between) or cracks are generated due to the lifting of the black matrix 21, resulting in a failure such as bursting of the sealing material (19).

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to provide a horizontal field type liquid crystal display device capable of preventing the sealing material from bursting by using a black matrix of a metallic material. .

In addition, the present invention provides a horizontal field type liquid crystal display device in which the width of the common electrode or the auxiliary electrode adjacent to the data line is larger than the cell gap, thereby preventing distortion of the horizontal electric field due to the black matrix of the metal material. have.

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

Horizontal field type liquid crystal display device of the present invention for achieving the above object is a first substrate; A second substrate including a metal black matrix; A plurality of gate lines arranged in a first direction on the first substrate; A plurality of data lines arranged in a second direction perpendicular to the gate line to define a plurality of pixel regions together with the gate line; A protective film formed on an entire surface of the first substrate including the data line; A switching element formed at an intersection of the gate line and the data line; A common electrode and a pixel electrode formed in the pixel region to generate a horizontal electric field; And a liquid crystal layer formed between the first substrate and the second substrate, wherein the common electrode includes a first common electrode formed in a center region of the pixel region and a second common electrode formed in a region adjacent to the data line. The first common electrode is formed on the same layer as the gate line, while the second common electrode is formed together with the pixel electrode on the passivation layer, and the width of the second common electrode is wider than the first substrate and the second electrode. It is characterized in that it is larger than the cell gap between the substrates.

The common electrode and the pixel electrode may be made of a transparent conductive material, and the common electrode and the pixel electrode may be formed in a bent structure. In this case, the data line may have the same bending structure as that of the common electrode and the pixel electrode.

The second substrate further includes a color filter formed on the black matrix.

In addition, another horizontal field type liquid crystal display device of the present invention is a first substrate; A second substrate including a metal black matrix; A plurality of gate lines arranged in a first direction on the first substrate; A plurality of data lines arranged in a second direction perpendicular to the gate line to define a plurality of pixel regions together with the gate line; A protective film formed on an entire surface of the first substrate including the data line; A switching element formed at an intersection of the gate line and the data line; A common electrode and a pixel electrode formed in the pixel region to generate a horizontal electric field; A liquid crystal layer formed between the first substrate and the second substrate; And an auxiliary electrode formed on an upper portion of the common electrode adjacent to the data line, wherein the common electrode is a first common electrode formed in the center region of the pixel region and a second common electrode formed in the region adjacent to the data line. The common electrode is formed on the same layer as the gate line, and the width of the auxiliary electrode formed on the second common electrode is greater than the cell gap between the first substrate and the second substrate.

A gate insulating layer and a protective layer formed between the common electrode and the auxiliary electrode are further included. In this case, the pixel electrode may be formed of a transparent conductive material.

As described above, the present invention improves adhesion to the second substrate by using a black matrix made of metal, thereby preventing the sealing member from bursting.

In addition, the present invention design the width of the common electrode adjacent to the data line larger than the cell gap, thereby preventing the distortion of the electric field due to the black matrix of the metal material. In addition, according to the present invention, by configuring the auxiliary electrode separately, and designing it larger than the cell gap, the electric field distortion caused by the black matrix may be prevented.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

3 is a plan view schematically showing a liquid crystal display device according to the present invention.

As shown in the figure, the liquid crystal display device 100 according to the present invention includes a thin film transistor array substrate 110 and a color filter substrate 120 and a liquid crystal layer (not shown) interposed therebetween.

The thin film transistor array substrate 110 includes a plurality of gate lines 101 arranged in a first direction and a plurality of liquid crystal cells defined by a plurality of data lines 103 vertically intersecting the gate lines 101. An image display unit 113 arranged to be connected to the image display unit 113, a gate pad 114 connected to the gate line 101 of the image display unit 113 to transmit an external signal, and a data pad connected to the data lines 103. 115).

In this case, the gate pad part 114 and the data pad part 115 are cut into unit panels, and are formed in the edge region of the thin film transistor array substrate 110 that does not overlap the color filter substrate 120. 114 supplies a gate signal supplied from a gate driver circuit (not shown) to the gate lines 101 of the image display unit 113, and the data pad unit 115 is supplied from a data driver circuit (not shown). The data signal to be supplied is supplied to the data lines 103 of the image display unit 113. In this case, the gate driving circuit may be formed separately on the outside or on the substrate.

Although not shown in the drawings, a thin film transistor is formed as a switching element for switching each liquid crystal cell in an area where the gate line 101 and the data line 109 cross each other. The thin film transistor includes a gate electrode, a semiconductor layer, and a source / drain electrode, and the gate electrode and the semiconductor layer are insulated by a gate insulating film (not shown) interposed therebetween. In this case, the gate insulating film (not shown) is formed over the entire surface of the thin film transistor array substrate 110, and a protective film (not shown) for protecting the thin film transistor is formed over the entire surface of the substrate. Therefore, a gate insulating film and a protective film are stacked on the thin film transistor array substrate 110 on the outside of the image display unit 113.

In addition, the color filter substrate 120 includes a color filter coated separately for each cell region, a switching element of the thin film transistor array substrate 110, a gate line 101, a data line 103, and an image display unit 113. A black matrix 121 is formed between the pad parts 114 and 115 to prevent light leakage, and the black matrix 121 is formed of a metal material such as chromium (Cr).

On the other hand, a sealing material 119 is formed on the upper substrate (color filter substrate; 120) corresponding to the outside of the thin film transistor array substrate 110 for bonding to the thin film transistor array substrate 110, and the image display unit Even if the sealing material 119 and the black matrix 121 overlap each other, since the black matrix 121 is formed of a metal material, it is possible to prevent the sealing material 119 from bursting.

The sealing member 119 may have an opening at one side thereof according to a method of forming a liquid crystal layer. That is, when the thin film transistor array substrate 110 and the color filter substrate 120 are bonded to each other by the sealing material 119 and then the liquid crystal layer is formed by the liquid crystal injection method, the liquid crystal may be injected into one side of the sealing material 119. Liquid crystal inlet must be provided separately. On the other hand, after dropping the liquid crystal, when the two substrates (thin film transistor array substrate, color filter substrate) to be bonded by the sealing material 119, as shown, the sealing material 119 should be formed in a closed shape. . The present invention includes both the sealing materials of the two types mentioned, regardless of the method of forming the liquid crystal layer.

4A and 4B illustrate in detail the unit pixels A defined by the gate lines and the data lines in FIG. 3. FIG. 4A is a plan view illustrating the unit pixels of the thin film transistor array substrate, and FIG. 4B is a plan view of FIG. A cross-sectional view of II-II 'shows a color filter substrate together.

As shown in the figure, the liquid crystal display device according to the present invention has a gate line 101 arranged in a first direction on a transparent first substrate 110 and a data line 103 crossing the gate line 101. The pixel area is defined by this.

A switching element 109 is formed at an intersection of the gate line 101 and the data line 103, and the switching element 109 is a gate electrode formed as part of the gate line 101 and a semiconductor formed on the gate electrode. And source / drain electrodes 102a and 102b formed on the semiconductor layer at predetermined intervals.

At least one pair of common electrodes 106 and 106 'and a pixel electrode 107 are formed in the pixel, and the first common electrode 106 and the data line are formed in the center region of the pixel region. And a second common electrode 106 'formed in a region adjacent to the 103. As shown in FIG.

In addition, the first common electrode connecting line 116a and the common electrode disposed at both ends of the common electrode 106 and 106 'in parallel with the gate line 101 and connecting one side of the common electrode 106 and 106'. A second common electrode connecting line 116b is formed to connect the other side of the 106 and 106 ', and both ends of the pixel electrode 107 are electrically connected to one side of the pixel electrode 107, and the first common The first pixel electrode connection line 117a overlapping the electrode connection line 116a to form the first storage capacitor Cst1, and the other side of the pixel electrode 107 are electrically connected to each other. A second pixel electrode connection line 117b overlapping with 116b to form a second storage capacitor Cst2 is formed.

The common electrodes 106 and 106 ′ are formed on the same layer as the gate line 101, and a passivation layer 111 is formed on the entire surface of the substrate including the data line 103, and the pixel electrode 107 is formed on the passivation layer. Is formed. In this case, the pixel electrode 107 is formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The pixel electrode 107 is electrically connected to the drain electrode 102b through the drain contact hole 118 formed on the passivation layer.

On the other hand, an auxiliary electrode 129 is formed on the passivation layer 111 corresponding to an upper portion of the second common electrode 106 'to contact the second common electrode 106' through a contact hole 128. In this case, the auxiliary electrode 129 has a width l larger than the cell gap d. This is to prevent the electric field distortion caused by the black matrix 121 of the metal material.

Although not shown in the drawing, instead of forming the auxiliary electrode 129, a second common electrode 106 ′ adjacent to the data line is formed on the passivation layer 111, and the width thereof is defined by the cell gap d. It is possible to form a wider, the present invention includes both cases.

In other words, the present invention forms an auxiliary electrode 129 having a width larger than the cell gap d on the passivation layer 111 on the second common electrode 106 ′ adjacent to the data line 103, or the auxiliary electrode. The second common electrode 106 ′ may be formed on the passivation layer 111, and the width of the second common electrode 106 ′ may be greater than that of the cell gap. When the second common electrode 106 ′ is formed on the passivation layer 111, the common electrodes 106 and 106 ′ may be formed of a transparent conductive material together with the pixel electrode 107.

Meanwhile, a black matrix 121 and a color filter 123 are formed on the second substrate 120 to prevent light leakage, and the black matrix 121 is formed of a metal material such as chromium. 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 (B) is disposed therebetween. 113) is formed.

The present invention configured as described above has an advantage of improving the aperture ratio by forming at least one of the common electrode 106 and the pixel electrode 107 with a transparent material.

Furthermore, in the present invention, the black matrix 121 is formed of a metal material, and the auxiliary electrode 129 having a width larger than a cell gap is further formed on the black matrix 121 and the common electrode 106 ′. By forming the common electrode 106b adjacent to the data line 103 on the protective film 111 and designing the width larger than the cell gap, the sealing material bursts while preventing the electric field distortion caused by the black matrix 121. You can stop it.

The present invention also provides a birefringence of the liquid crystal by forming the common electrode, the pixel electrode, and the data line 103 in a bent structure to form a multi-domain structure in which the driving direction of the liquid crystal is symmetrical. The abnormal light due to the characteristics is canceled with each other to minimize the color shift phenomenon. That is, the color shift occurs depending on the birefringence characteristics of the liquid crystal, and the color shift occurs. In particular, a yellow shift is observed in the short axis direction of the liquid crystal and a blue shift in the long axis direction. ) Is observed. Therefore, when the short axis and the long axis of the liquid crystal are appropriately arranged, it is possible to reduce the color transition by compensating the birefringence value.

For example, in the case of 2-domain in which the liquid crystal molecules are symmetrical to each other, as shown in FIG. 5, the birefringence value of A ′ of the first liquid crystal molecule 213a is opposite to that of the first liquid crystal molecule 213a. The birefringence value of A2 of the second liquid crystal molecules 213a taking the molecular arrangement in the direction is compensated, and as a result, the birefringence value becomes about zero. In addition, the birefringence value of c1 is compensated by c2. Therefore, by minimizing the color transition phenomenon due to the birefringence characteristics of the liquid crystal, it is possible to prevent the deterioration of the image quality according to the viewing angle.

As described above, according to the present invention, a metal black matrix is used, and an auxiliary electrode having a width wider than the cell gap is added to a region corresponding to the black matrix, or the width of the common electrode adjacent to the data line is larger than the cell gap. By designing large, not only the signal distortion caused by the black matrix can be prevented, but also the bursting of the sealing material due to the decrease in adhesion between the black resin and the substrate can be prevented.

As such, the present invention has the effect of preventing the bursting of the sealing material to improve the yield of the product.

Claims (8)

A first substrate; A second substrate including a metal black matrix; A plurality of gate lines arranged in a first direction on the first substrate; A plurality of data lines arranged in a second direction perpendicular to the gate line to define a plurality of pixel regions together with the gate line; A protective film formed on an entire surface of the first substrate including the data line; A switching element formed at an intersection of the gate line and the data line; A common electrode and a pixel electrode formed in the pixel region to generate a horizontal electric field; And A liquid crystal layer formed between the first substrate and the second substrate, The common electrode includes a first common electrode formed in a center region of the pixel region and a second common electrode formed in a region adjacent to the data line. The first common electrode is formed on the same layer as the gate line, while the second common electrode is formed together with the pixel electrode on the passivation layer, and the width of the second common electrode is between the first substrate and the second substrate. A horizontal field type liquid crystal display device, characterized in that it is larger than the cell gap. The method of claim 1, And the common electrode and the pixel electrode are made of a transparent conductive material. The method of claim 1, And the common electrode and the pixel electrode have a bending structure. The method of claim 3, And the data line has a bending structure. The method of claim 1, The second substrate, And a color filter formed on the black matrix. A first substrate; A second substrate including a metal black matrix; A plurality of gate lines arranged in a first direction on the first substrate; A plurality of data lines arranged in a second direction perpendicular to the gate line to define a plurality of pixel regions together with the gate line; A protective film formed on an entire surface of the first substrate including the data line; A switching element formed at an intersection of the gate line and the data line; A common electrode and a pixel electrode formed in the pixel region to generate a horizontal electric field; A liquid crystal layer formed between the first substrate and the second substrate; And An auxiliary electrode formed on the common electrode adjacent to the data line; The common electrode includes a first common electrode formed in a center region of the pixel region and a second common electrode formed in a region adjacent to the data line. The common electrode is formed on the same layer as the gate line, and the width of the auxiliary electrode formed on the second common electrode is larger than the cell gap between the first substrate and the second substrate. Display element. The method of claim 6, And the second common electrode is in contact with the auxiliary electrode through a contact hole formed in the passivation layer thereon. The method of claim 6, And said pixel electrode is formed of a transparent conductive material.

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