KR101267078B1 - Array substrate and liquid crystal display of in-plane switching mode using the same - Google Patents

Abstract

The present invention is to suppress the light leakage by adjusting the structure of the pixel electrode and the common electrode in the light leakage region and the distance between the two electrodes, the gate line and data line intersecting on the first substrate, the first substrate to define the pixel region A thin film transistor formed at an intersection of the gate line and the data line, a common line formed in parallel with the gate line, a plurality of common electrodes branched from the common line, and a plurality of pixel electrodes formed in parallel with the common electrode and connected to each other through an extraction line The array substrate and a transverse electric field type liquid crystal display using the array substrate, wherein the edges of the pixel electrodes facing the common line at predetermined intervals protrude.

Liquid Crystal Display, Array Board, Transverse Field Type

Description

Array substrate and liquid crystal display device using the same {Array substrate and liquid crystal display of in-plane switching mode using the same}

1 is a partial plan view of an array substrate according to the prior art.

2 is a plan view of an array substrate according to a first embodiment of the present invention.

FIG. 3 is a cross-sectional view of the liquid crystal display device corresponding to the line II-II 'of FIG. 2.

4 is a plan view of an array substrate according to a second embodiment of the present invention.

5 is a plan view of an array substrate according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view of the liquid crystal display device corresponding to lines III-III ′ and IV-IV ′ of FIG. 5.

DESCRIPTION OF THE REFERENCE NUMERALS (S)

100: array substrate TFT: thin film transistor

110: gate line 111: gate electrode

112: semiconductor layer 120: data line

121: source electrode 122: drain electrode

124: contact hole 130: withdrawal line

131, 132, and 133: pixel electrodes 140 and 142: common line

141 and 143: common electrode 200: color filter substrate

210: black matrix 220: color filter

300: liquid crystal layer

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

The liquid crystal display device forms a liquid crystal layer having anisotropic dielectric constant between the color filter substrate, which is a transparent insulating substrate, and the array substrate, and then adjusts the intensity of the electric field formed in the liquid crystal layer to change the molecular arrangement of the liquid crystal material. It is a display device which expresses a desired image by adjusting the amount of light transmitted to a color filter substrate which is a surface.

In recent years, by forming a pixel electrode and a common electrode of a liquid crystal display device together on an array substrate and driving a liquid crystal using a horizontal electric field between the two electrodes, the demand for a transverse electric field system having a wider viewing angle is increasing.

In general, the transverse electric field type liquid crystal display devices are disposed to face each other, and include a color filter substrate and an array substrate provided with a liquid crystal layer therebetween.

The color filter substrate is formed with a black matrix to prevent light leakage and color filters of red, green, and blue to implement color.

The array substrate is formed with a gate line and a data line defining a pixel region, a thin film transistor positioned at an intersection point of two lines, a common electrode and a pixel electrode alternately arranged in each pixel region to generate a horizontal electric field.

1 is a partial plan view of an array substrate according to the prior art.

The array substrate includes a plurality of pixel regions arranged in a matrix form, and the pixel electrodes 10 and the common electrode 20 that are alternate with each other are arranged in each pixel region as shown in FIG. 1.

In the region where the pixel electrode 10 and the common electrode 20 cross in parallel, a horizontal electric field in the E1 direction is generated, whereby the long axis of the liquid crystal is arranged in parallel to the electric field.

On the other hand, in the light leakage region R1 where the end of the pixel electrode 10 is positioned, an electric field in the E1 direction and an electric field in the E2 direction between the pixel electrode 10 and the common electrode 20 are added to generate a foreground line. This foreground line causes the brightness to decrease.

In addition, when the common electrode 20 and the pixel electrode 10 have a bent structure, rubbing is performed well according to the bent structure and rubbing conditions of the pixel region when the rubbing process is performed in a constant direction DR. It is inevitable that stepped sections will be created.

The light leakage region R1 is a stepped portion having poor rubbing. In the light leakage region R1, the initial alignment of the liquid crystal material is uneven, resulting in a strong light leakage, thereby causing an increase in black brightness and a decrease in contrast ratio.

Conventionally, in order to reduce such light leakage, a method of covering all of the stepped portions of the pixel area by increasing the line width BM_W of the black matrix 30 formed on the upper color filter substrate is adopted.

However, in this case, since the line width BM_W of the black matrix 30 is excessively extended by being applied up to the bonding margin of the color filter substrate and the array substrate, the aperture ratio and the luminance are deteriorated.

Accordingly, an aspect of the present invention is to reduce the line width of the black matrix, to control the structure of the pixel electrode and the common electrode in the light leakage region and to suppress the light leakage by adjusting the distance between the two electrodes, to provide an array substrate that can improve the image quality It is.

Another object of the present invention is to provide a transverse electric field type liquid crystal display device to which the above-described array substrate is applied.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the precise forms disclosed. Other objects, which will be apparent to those skilled in the art, It will be possible.

An array substrate according to the present invention for achieving the above technical problem is a first substrate; A gate line and a data line intersecting the first substrate to define a pixel area; A thin film transistor formed at an intersection of the gate line and the data line; A common line formed in parallel with the gate line and a plurality of common electrodes branched from the common line; A plurality of pixel electrodes formed in parallel with the common electrode and connected to each other through a lead-out line, and a part of the common line facing the end of the pixel electrode protrudes, but the end of the pixel electrode protrudes from the common A portion of the lead-out line facing the end of the common electrode protrudes without overlapping a portion of the line, but the end of the common electrode does not overlap with a portion of the lead-out line protruding.

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In addition, in the transverse field type liquid crystal display according to the present invention, a plurality of pixel regions are arranged in a matrix form, a pixel electrode and a plurality of common electrodes parallel to each other are formed in each of the pixel regions, and the common electrodes are connected to each other. A first substrate having a drawing line connecting the common line and the pixel electrode to each other; A second substrate disposed to face the first substrate and having a black matrix and a color filter; And a liquid crystal layer formed between the first substrate and the second substrate, wherein a part of the common line facing the end of the pixel electrode protrudes, but an end of the pixel electrode is part of the protruding common line. A portion of the lead-out line facing the end of the common electrode is not overlapped, but the end of the common electrode is not overlapped with a portion of the lead-out line protruding.

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

Hereinafter, an array substrate and a transverse electric field type liquid crystal display using the same according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a plan view of an array substrate according to a first exemplary embodiment of the present invention, and FIG. 3 is a cross-sectional view of a liquid crystal display device corresponding to lines II-II 'of FIG. 2.

2 and 3, the array substrate 100 according to the first embodiment of the present invention is composed of a plurality of pixel regions P arranged in a matrix form, and the liquid crystal display is bonded at regular intervals. It is configured to include the array substrate 100 and the color filter substrate 200, the liquid crystal layer 300 therebetween.

As illustrated in FIG. 2, the array substrate 100 may be disposed to cross each other and be spaced apart from each other in parallel with the gate line 110, the data line 120, and the gate line 110 defining the pixel area P. 140, the thin film transistor TFT positioned at the intersection of the gate line 110 and the data line 120, and the pixel electrode 131 and the common electrode 141 disposed on the pixel region P to cross each other. Include.

In more detail, the gate line 110 and the common line 140 are parallel to each other in the horizontal direction on the array substrate 100, and the data line 120 is bent in the vertical direction, and the common electrode ( 141 and the pixel electrode 131.

The pixel electrode 131 is disposed in parallel with the common electrode 141 from the lead line 130 to be parallel to each other, and is in contact with the drain electrode 122 of the thin film transistor TFT through the contact hole 124.

The common electrode 141 and the pixel electrode 131 are formed in plural, and the common electrodes 141 are connected to each other through the common line 140 formed in a direction parallel to the gate line 110, and the pixel electrode ( 131 are connected to each other by the lead line 130.

The common electrode 141 and the pixel electrode 131 are formed on the passivation layer 102 which is coplanar, as shown in FIG. 3.

The thin film transistor TFT is disposed between the gate electrode 111 extending from the gate line 110, the semiconductor layer 112 formed on the gate electrode 111, and the gate electrode 111 and the semiconductor layer 112. The gate insulating layer 101 and the semiconductor layer 112 include a source electrode 121 and a drain electrode 122 formed to face each other. Although not shown, an ohmic contact layer made of a material of n + hydrogenated amorphous silicon in which n-type impurities are heavily doped at an interface between the source electrode 121 and the drain electrode 122 and the semiconductor layer 112. Is formed.

A gate insulating layer 101 is formed on the gate electrode 111, and a semiconductor layer 112 made of an undoped amorphous silicon material is formed on the gate insulating layer 101.

The passivation layer 102 made of a material such as a silicon nitride layer SiNx is formed on the thin film transistor TFT. Although not shown, an alignment layer is formed on the front surface of the array substrate 100 and the color filter substrate 200 facing each other to be rubbed.

A black matrix 210 is formed in the color filter substrate 200 to block light in portions other than the pixel region P, and red, green, and white colors may be formed in portions corresponding to the pixel regions P. A blue color filter 220 is formed.

The liquid crystal display device having such a configuration orientates the liquid crystal layer 300 formed between the array substrate 100 and the color filter substrate 200 by a horizontal electric field formed between the pixel electrode 131 and the common electrode 141. The amount of light transmitted is adjusted according to the degree of alignment of the liquid crystal layer 300 to display an image.

As shown in FIG. 2, the end edge of the pixel electrode 131 is formed to extend toward the portion where the common electrode 141 branches from the common line 140, particularly, the light leakage region R2.

The light leakage region R2 is a portion of the portion where the common line 140 and the common electrode 141 contact each other, and an area in which the initial alignment of the liquid crystal becomes uneven during rubbing due to the step difference, and a foreground line is generated so that a uniform horizontal electric field is not formed. to be.

When rubbing is performed in a predetermined rubbing direction DR, a stepped portion of the electrode is formed, and rubbing is not performed well at a portion where the rubbing hair is swept away, resulting in a light leakage region R2 in which the initial alignment of the liquid crystal becomes uneven. .

In the case of FIG. 2, when the rubbing hair advances in the rubbing direction DR, a phenomenon in which the rubbing hair is swept away from a part of the contact portion of the common line 140 and the common electrode 141 occurs, which causes light leakage to become stronger. It becomes the light leakage area R2.

Accordingly, the light leakage region R2 is formed such that the end shape of the pixel electrode 131 facing the common line 140 protrudes so that the edge of the end of the pixel electrode 131 is in contact with the common line 140 and the common electrode 141. To extend toward

As a result, the size of the light leakage region R2 may be reduced, and the foreground line may be reduced by widening the section in which the transverse electric field is generated in the direction of the light leakage region R2 at the end of the pixel electrode 131.

In this case, only a portion corresponding to one edge of the edge portion of the pixel electrode 131 may be extended, or the edge of the edge of the extended portion may be sharply formed.

As such, by controlling the distance between the pixel electrode 131 and the common electrode 141 or the pixel electrode 131 and the common line 140 by adjusting the shape of the end portion of the pixel electrode 131, the light leakage strongly occurs. Light leakage may be reduced by reducing the size of the region R2.

In addition, when the size of the light leakage region R2 decreases, the line width BM_W of the black matrix 210 may be reduced to improve the aperture ratio and the image quality.

In this case, the line width BM_W of the black matrix 210 is reduced in correspondence to the extent to which the end edges of the pixel electrode 131 extend.

In particular, when the black matrix 210 is formed of a resin material other than metal such as chromium (Cr), the electrode pattern of the resin material is not formed to have a clean line width compared to the metal, and thus shakes. When the black matrix 210 overlaps the large light leakage region R2, the display characteristics may be further reduced. Thus, the line width BM_W of the black matrix 210 may be adjusted by adjusting the shape of the end of the pixel electrode 131. By reducing, this problem is solved.

In addition, as in the upper region of the pixel region P, since the light leakage occurs between the pixel electrode 131 and the common electrode 141 in the lower region Z1, the lower region Z1 may also be formed in the upper region. Similarly, the light leakage may be adjusted by modifying the shape of the end of the common electrode 141.

In this case, the end edges of the common electrode 141 facing the lead line 130 at regular intervals are projected so that the end edges of the common electrode 141 are the lead line 130 and the pixel electrode 131. It extends toward the contact area.

4 is a plan view of an array substrate according to a second embodiment of the present invention.

Referring to FIG. 4, compared to the first embodiment, both edges of the end of the pixel electrode 132 extend and both sides of the pixel electrode 132 are formed to have a longer length, so that the pixel electrode 132 has a common line. It is disposed closer to the 140 side.

By applying the pixel electrode 132 formed by extending the edge of the end portion and extending the entire length of the end portion, as shown in FIG. 3, the size of the light leakage region R3 is reduced and at the end portion of the pixel electrode 132. The foreground line may be reduced by widening the section in which the horizontal electric field is generated in the direction of the light leakage region R3.

In the lower region Z2, light leakage may be adjusted by modifying an end shape of the common electrode 141. That is, the end edges of the common electrode 141 facing the lead line 130 at regular intervals protrude to one side or both sides, so that the end edges of the common electrode 141 are the lead line 130 and the pixel electrode ( 132 extends toward the abutting area.

Since the other components of FIG. 4 correspond to those of the first embodiment shown in FIGS. 2 and 3, a detailed description thereof will be omitted.

5 is a plan view of an array substrate according to a third exemplary embodiment of the present invention, and FIG. 6 is a cross-sectional view of a liquid crystal display device corresponding to lines III-III ′ and IV-IV ′ of FIG. 5.

5 and 6, in the array substrate according to the third embodiment, a portion of the pixel electrode 133 disposed between the two common electrodes 143 and an end portion of the pixel electrode 133 facing each other is formed to protrude. A common line 142.

The liquid crystal display device includes a liquid crystal layer 300 formed between the array substrate 100, the color filter substrate 200 facing the array substrate 100 at regular intervals, the array substrate 100, and the color filter substrate 200. It includes.

In each pixel area P of the array substrate 100, a gate line 110 formed in a horizontal direction and a data line 120 formed in a direction perpendicular to the gate line 110 to define the pixel area P are arranged. do.

In each pixel area P, a common electrode 143 branched from the common line 142 and a pixel electrode 133 branched from the lead line 130 are formed in parallel with each other, and the gate line 110 and the data line ( The thin film transistor TFT is formed at an intersection portion of the 120.

The thin film transistor TFT is turned on by the scan signal from the gate line 110 to transfer the data voltage applied to the data line 120 to the pixel electrode 133.

The thin film transistor TFT includes a gate electrode 111, a gate insulating layer 101 thereon, a semiconductor layer 112, and source / drain electrodes 121 and 122, and a passivation layer on the thin film transistor TFT. 102 is configured.

Here, the common electrode 143 and the pixel electrode 133 are formed on the passivation layer 102 that is coplanar, and have a relatively high transmittance of light such as indium-tin oxide (ITO). Consists of metal.

The color filter substrate 200 includes a black matrix 210 formed of a resin material and blocking light leakage, and a color filter 220 corresponding to each pixel region P. As the color filter 220, red, green, and blue color filters are formed.

Referring to FIG. 5, as the portion of the common line 142 protrudes, the size of the light leakage region R4 is reduced, and the distance between the common line 142 and the pixel electrode 133 is reduced, so that the pixel electrode 133 is reduced. The line width BM_W of the black matrix 210 may be reduced in correspondence to the extent of the portion of the common line 142 facing the end of the black matrix 210.

As described above, the portion of the common line 142 facing the end of the pixel electrode 133 may be projected to reduce the size of the light leakage region R4 and reduce the foreground line, thereby improving the luminance degradation due to the foreground line and the light leakage. Can be.

Similarly, in the lower region Z3, light leakage may be adjusted by protruding a part of the lead line 130 facing the end of the common electrode 142.

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

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

The array substrate and the transverse field type liquid crystal display using the same according to the present invention made as described above reduce the line width of the black matrix, control the structure of the pixel electrode and the common electrode in the light leakage region, and suppress the light leakage by controlling the distance between the two electrodes. Can be improved.

Claims (22)

delete delete delete delete delete delete delete A first substrate; A gate line and a data line intersecting the first substrate to define a pixel area; A thin film transistor formed at an intersection of the gate line and the data line; A common line formed in parallel with the gate line and a plurality of common electrodes branched from the common line; Is formed in parallel with the common electrode, and includes a plurality of pixel electrodes connected to each other through the lead line, A part of the common line facing the end of the pixel electrode protrudes, but the end of the pixel electrode does not overlap a part of the protruding common line, And a portion of the lead-out line facing the end of the common electrode protrudes, but the end of the common electrode does not overlap with the portion of the lead-out line protruding. delete delete delete delete delete delete delete delete delete delete A plurality of pixel regions are arranged in a matrix form, and a pixel electrode and a plurality of common electrodes parallel to each other are formed in each of the pixel regions, and a common line connecting the common electrodes to each other and a drawing line connecting the pixel electrodes to each other. A formed first substrate; A second substrate disposed to face the first substrate and having a black matrix and a color filter; And A liquid crystal layer formed between the first substrate and the second substrate, A part of the common line facing the end of the pixel electrode protrudes, but the end of the pixel electrode does not overlap a part of the protruding common line, And a portion of the lead-out line facing the end of the common electrode protrudes, but the end of the common electrode does not overlap with the portion of the lead-out line protruding from the common electrode. delete 20. The method of claim 19, The black matrix, And a line width is reduced in correspondence to the degree of protrusion of a portion of the common line facing the end of the pixel electrode. 20. The method of claim 19, The black matrix, A transverse electric field liquid crystal display device formed from a resin material.

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