KR100612993B1 - Liquid crystal displays and panels for the same - Google Patents

Abstract

Gate lines are formed on the substrate in the horizontal direction, and protrusion patterns are formed on the same layer as the gate lines with the same material as the gate lines. A gate insulating film is formed on the gate line and the projection pattern, and a semiconductor layer, a source and a drain electrode, and the like that form the data line and the thin film transistor are formed on the gate insulating film. A protective film is formed on the data line and the like, and a pixel electrode is formed on the protective film so as to overlap the projection pattern. The pixel electrode is affected by the projection pattern and has protrusions along the projection pattern. In this case, an opening pattern and protrusions can be formed to secure a wide viewing angle without additional processing at all, compared to a conventional vertical alignment liquid crystal display device, and the common electrode voltage is increased or expensive because the common electrode of the upper panel is not patterned. The problem that an overcoat film should be formed is eliminated.

LCD, Projection, Opening, Gate Wiring, Data Wiring, Photosensitive Film

Description

Wide viewing angle liquid crystal display device and substrate used therefor {LIQUID CRYSTAL DISPLAYS AND PANELS FOR THE SAME}

1 and 2 are cross-sectional views of a liquid crystal display device according to the prior art, respectively,

3 is a layout view of a thin film transistor substrate for a liquid crystal display device according to a first and second embodiment of the present invention;

FIG. 4 is a cross-sectional view taken along line IV-IV ′ of FIG. 3 and shows a thin film transistor substrate for a liquid crystal display according to a first embodiment of the present invention.

FIG. 5 is a cross-sectional view taken along line IV-IV ′ of FIG. 3 and shows a thin film transistor substrate for a liquid crystal display according to a second exemplary embodiment of the present invention.

6 is a layout view of a thin film transistor substrate for a liquid crystal display device according to a third and fourth embodiment of the present invention;

FIG. 7 is a cross-sectional view taken along line VII-VII ′ of FIG. 6 and shows a thin film transistor substrate for a liquid crystal display according to a third exemplary embodiment of the present invention.

FIG. 8 is a cross-sectional view taken along line VII-VII ′ of FIG. 6 and shows a thin film transistor substrate for a liquid crystal display according to a fourth exemplary embodiment of the present invention.

9 is a cross-sectional view of a liquid crystal display according to a first embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a thin film transistor substrate used therein, and more particularly, to a vertically aligned liquid crystal display device forming an opening pattern and a projection in a pixel electrode, and a thin film transistor substrate used therein.

In general, a liquid crystal display device injects a liquid crystal material between an upper substrate on which a common electrode, a color filter, and the like are formed, and a lower substrate on which a thin film transistor and a pixel electrode are formed. By applying a different potential to form an electric field to change the arrangement of the liquid crystal molecules, and through this to control the light transmittance is a device that represents the image.

However, it is an important disadvantage that the liquid crystal display device has a narrow viewing angle. In order to overcome these disadvantages, various methods for widening the viewing angle have been developed. Among them, liquid crystal molecules are oriented vertically with respect to the upper and lower substrates, and a method of forming a constant opening pattern or forming protrusions on the pixel electrode and the common electrode opposite thereto is performed. This is becoming potent.

In the conventional method of forming the opening pattern, an opening pattern is formed on the pixel electrode and the common electrode, and the viewing angle is widened by adjusting the direction in which the liquid crystal molecules lie down using a fringe field formed by the opening patterns. There is this.

However, in this case, since the common electrode made of indium tin oxide (ITO) formed on the color filter is patterned by using photolithography, a photolithography process is added.

In addition, the adhesion between the ITO deposited on the color filter by sputtering and the color filter resin is not good, so that the precision of the common electrode is inferior. In addition, there is a problem that damage occurs when the color filter is exposed during ITO etching, in order to prevent this, a reliable organic insulating film (overcoat film) must be coated on the color filter. However, there is a problem that the overcoat film is expensive. When the overcoat layer is formed, the common electrode may not directly contact a black matrix formed of chromium (Cr) or the like, thereby causing a problem such as an increase in resistance and severe flicker defects.

In addition, since an opening pattern is formed in the common electrode, an increase in resistance of the common electrode is increased.

On the other hand, when the upper and lower substrates are aligned, the opening pattern formed on the common electrode of the upper plate and the opening pattern formed on the pixel electrode of the lower plate also have difficulty in accurately aligning.

As shown in FIG. 1, the projection is formed by forming projections 6 and 7 on the pixel electrodes 3 and the common electrode 4 formed on the upper and lower substrates 1 and 2, respectively. It is a method of controlling the lying direction of the liquid crystal molecules by using the electric field distorted by (6, 7).

In this manner, the process of forming the upper and lower substrate (1, 2) projections must be added, there is a problem that the production cost increases and the upper and lower projections (6, 7) must be aligned correctly.

As another method, as shown in FIG. 2, an opening pattern 7 is formed on the pixel electrode 3 formed on the lower substrate 1, and the common electrode 4 formed on the upper substrate 2. The protrusion 6 is formed on the top to form a domain by adjusting the opening pattern 7 and the fringe field formed by the protrusion 6 in the lying direction of the liquid crystal.

In this manner as well, the process of forming the protrusions 6 on the common electrode 4 has to be added, as well as the difficulty of accurately aligning the protrusions 6 and the opening pattern 7 when the upper and lower substrates 1 and 2 are aligned. .

The technical problem to be achieved by the present invention is to improve the image quality of the liquid crystal display device.

In order to solve this problem, in the present invention, the projection pattern is formed together with the wiring.

Specifically, the gate line is formed on the insulating substrate, and the first protrusion pattern is formed on the same layer as the gate line with the same material as the gate line. The data line is insulated from and crosses the gate line, and the pixel electrode is formed to overlap the first protrusion pattern on the first protrusion pattern. A substrate for a liquid crystal display device having a structure in which a switching element for transmitting or blocking an image signal transmitted through a data line to a pixel electrode according to a scan signal transmitted through a gate line is formed.

In this case, a second protrusion pattern formed of the photosensitive material on the first protrusion pattern and having the same planar shape as the first protrusion pattern may be further formed.

Alternatively, the first protrusion pattern may be formed of the same material as the data line on the same layer as the data line.

Next, a structure of a thin film transistor substrate for a liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to the drawings.

3 is a layout view of a thin film transistor substrate for a liquid crystal display device according to the first and second embodiments of the present invention, and FIG. 4 is a cross-sectional view taken along line IV-IV ′ of FIG. 3, according to the first embodiment of the present invention. A thin film transistor substrate for a liquid crystal display device.

First, gate wirings, sustain electrode wirings, and projection patterns 21 made of metal such as aluminum or aluminum alloy are formed on the insulating substrate 10. The gate line is connected to the gate line 22 and the gate line 22 which extend in the horizontal direction, and a gate pad (not shown) and a gate line which receive a gate signal from the outside and transfer the gate signal to the gate line 22. A storage electrode wire (not shown) including the gate electrode 26 of the thin film transistor which is part of the 22, wherein the storage electrode wiring is connected to the end of the storage electrode line 27 and the storage electrode line 27 extending in the horizontal direction. It includes. The protruding pattern 21 is arranged in such a manner that several crosses are vertically connected. The projection pattern 21 is also symmetrical up and down and left and right. In addition, the protrusion pattern 21 is connected to the storage electrode line 27 and also functions to form the storage capacitor by overlapping the pixel electrode 91 as described later.

At this time, the gate wirings 22 and 26, the sustain electrode wiring 27, and the projection pattern 21 may be formed in a single layer, but may also be formed in a double layer or a triple layer. In the case of forming a single layer, it is made of aluminum (Al) or aluminum (Al) -neodymium (Nd) alloy. In case of forming a double layer, the lower layer is made of aluminum (Al) -neodymium (Nd) alloy, and the upper layer is made of molybdenum ( Mo) -tungsten (W) alloy can be made. At this time, the thickness of the projection pattern 21 is set to 2,500 kPa or more. In addition, the side inclination angle of the projection pattern 21 is formed to be 45 ° or less. This is possible through wet etching and dry etching.

A gate insulating film 30 made of silicon nitride (SiN _x ) is formed on the gate wirings 22 and 26, the storage electrode wiring 27, and the protrusion pattern 21.

A semiconductor layer 40 made of a semiconductor such as hydrogenated amorphous silicon is formed on the gate insulating layer 30. The semiconductor layer 40 overlaps the gate electrode 26.

On the semiconductor layer 40, contact layers 55 and 56 made of a material such as n + hydrogenated amorphous silicon that are heavily doped with n-type impurities are formed. The contact layers 55 and 56 are separated on both sides with respect to the gate electrode 26.

On the contact layers 55 and 56, data lines 62, 65 and 66 made of chromium (Cr) or molybdenum-tungsten alloy are formed. The data lines 62, 65, and 66 are formed in a vertical direction and connected to one end of the data line 62 and the data line 62, which are connected to the source electrode 65 formed on one contact layer 55. A data pad (not shown) receiving data signals from the outside, separated from the data line 62, and disposed on the contact layer 56 opposite to the source electrode 65 with respect to the gate electrode 26. A drain electrode 66 is formed. At this time, the data lines 62, 65, and 66 may be formed in a single layer like the gate lines 22, 26, but may be formed in a double layer or a triple layer. Of course, when forming more than two layers, it is preferable that one layer is made of a material having a low resistance and the other layer is made of a material having good contact properties with other materials.

The protective film 70 is formed on the data wires 62, 65, 66. The protective insulating layer 70 covers and protects at least the channel portion between the source electrode 65 and the drain electrode 66, and in this embodiment, the contact hole 74 exposing not only the channel portion but also the drain electrode 66. ) And the data wirings 62, 65, and 66 except for the contact hole exposing the data pad.

A pixel electrode 91 made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) is formed on the passivation layer 70. A pixel electrode (on the gate pad, the sustain electrode pad, and the data pad) is formed on the passivation layer 70. An auxiliary pad (not shown) made of the same material as 91 is formed. The protrusion P is formed on the pixel electrode 91 along the protrusion pattern 21 due to the influence of the protrusion pattern 21 formed on the same layer as the gate lines 22 and 26.

The pixel electrode 91 is connected to the exposed drain electrode 66, and the left and right sides are indented at regular intervals to form an opening. The openings are symmetrical up, down, left and right, and partition the pixel electrode 91 into four small regions. In addition, the pixel electrodes 91 are arranged to be symmetrical in the vertical and horizontal directions with respect to the projection pattern 21, so that four small regions of the pixel electrode 91 are divided into four equal parts by the projection pattern 21. FIG.

The pixel electrode 91 overlaps the protrusion pattern 21, and the protrusion pattern 21 is connected to the storage electrode line 27. Therefore, a sufficient storage capacitance can be formed between the pixel electrode 91 and the projection pattern 21.

Now, a liquid crystal display substrate according to a second embodiment of the present invention will be described.

FIG. 5 is a cross-sectional view taken along line IV-IV ′ of FIG. 3 and illustrates a thin film transistor substrate for a liquid crystal display according to a second exemplary embodiment of the present invention.

In the second embodiment, the photoresist patterns 81 and 82 are further formed on the substrate for the liquid crystal display according to the first embodiment, over the sustain electrode lines 27 and the gate lines 22 and 26. The photoresist patterns 81 and 82 are left without removing the photoresist patterns 81 and 82 used in the photolithography process for forming the projection patterns 21, the storage electrode lines 27, the gate wirings 22 and 26, and the like. will be. Therefore, the photoresist patterns 81 and 82 have the same planar shape as the protrusion patterns 21.

The photoresist patterns 81 and 82 serve to increase the projection, and for this purpose, the photoresist patterns 81 and 82 are preferably set to 10,000 GPa or more. In addition, the photoresist patterns 81 and 82 should have sufficient adhesive strength with the upper and lower layers so as not to fall off in a subsequent chemical vapor deposition process of 300 ° or more. As such photosensitive resin, acrylic resin is generally used.

A liquid crystal display according to a third embodiment of the present invention will be described.

6 is a layout view of a thin film transistor substrate for a liquid crystal display device according to a third and fourth embodiments of the present invention, and FIG. 7 is a cross-sectional view taken along line VII-VII 'of FIG. A thin film transistor substrate for a liquid crystal display device.

First, gate wirings and sustain electrode wirings made of metal such as aluminum or aluminum alloy are formed on the insulating substrate 10. The gate line is connected to the gate line 22 and the gate line 22 extending in the horizontal direction so that a gate pad (not shown) and a gate line 22 which receive a gate signal from the outside and transfer the gate signal to the gate line are provided. A gate electrode 26 of the thin film transistor, which is a part of the transistor, and the storage electrode wiring includes a storage electrode line 27 extending in the horizontal direction and a storage electrode pad (not shown) connected to an end of the storage electrode line 27. . At this time, the gate wirings 22 and 26 and the storage electrode wiring 27 may be formed as a single layer, but may be formed as a double layer or a triple layer.

A gate insulating layer 30 made of silicon nitride (SiN _x ) is formed on the gate lines 22 and 26.

A semiconductor layer 40 made of a semiconductor such as hydrogenated amorphous silicon is formed on the gate insulating film 30. The semiconductor layer 40 overlaps the gate electrode 26.

On the semiconductor layer 40, contact layers 55 and 56 made of a material such as n + hydrogenated amorphous silicon that are heavily doped with n-type impurities are formed. The contact layers 55 and 56 are separated on both sides with respect to the gate electrode 26.

On the contact layers 55 and 56, data lines 62, 65 and 66 made of chromium (Cr) or molybdenum-tungsten alloy are formed. The data lines 62, 65, and 66 are formed in a vertical direction and connected to one end of the data line 62 and the data line 62, which are connected to the source electrode 65 formed on one contact layer 55. A data pad (not shown) receiving data signals from the outside, separated from the data line 62, and disposed on the contact layer 56 opposite to the source electrode 65 with respect to the gate electrode 26. A drain electrode 66 is formed. At this time, the data lines 62, 65, and 66 may be formed in a single layer like the gate lines 22, 26, but may be formed in a double layer or a triple layer.

A protrusion pattern 61 made of the same material as the data lines 62, 65, and 66 is formed on the gate insulating layer. The protrusion patterns 21 are arranged in a shape in which several crosses are vertically connected to a pixel area, which is an area where two adjacent data lines 62 and two gate lines 22 cross each other. The protruding pattern 21 is also symmetrical in the vertical direction, and one of the horizontal branches overlaps the storage electrode line 27. This is to minimize the decrease in the aperture ratio by overlapping elements as far as possible through which light cannot pass.

The passivation film 70 is formed on the data wires 62, 65, 66, and the projection pattern 61. The protective insulating layer 70 covers and protects at least the channel portion between the source electrode 65 and the drain electrode 66, and in this embodiment, the contact hole 74 exposing not only the channel portion but also the drain electrode 66. ) And the data wirings 62, 65, and 66 except for the contact hole exposing the data pad.

A pixel electrode 91 made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) is formed on the passivation layer 70. A pixel electrode (on the gate pad, the sustain electrode pad, and the data pad) is formed on the passivation layer 70. An auxiliary pad (not shown) made of the same material as 91 is formed. The protrusion P is formed on the pixel electrode 91 along the protrusion pattern 21 due to the influence of the protrusion pattern 21 formed on the same layer as the gate lines 22 and 26.

The pixel electrode 91 is in contact with the exposed drain electrode 66, and the left and right sides are indented at regular intervals to form an opening. The openings are symmetrical up, down, left and right, and partition the pixel electrode 91 into four small regions. In addition, the pixel electrodes 91 are arranged to be symmetrical in the vertical and horizontal directions with respect to the projection pattern 21, so that four small regions of the pixel electrode 91 are divided into four equal parts by the projection pattern 21. FIG.

A substrate for a liquid crystal display device according to a fourth embodiment of the present invention will be described.

FIG. 8 is a cross-sectional view taken along line VII-VII ′ of FIG. 6 and illustrates a thin film transistor substrate for a liquid crystal display according to a fourth exemplary embodiment.

In the fourth embodiment, the photoresist patterns 81 and 82 are further formed on the data lines 62, 65, and 66, as well as the projection patterns 21, on the liquid crystal display substrate according to the third embodiment. The photoresist patterns 81 and 82 are left without removing the photoresist patterns 81 and 82 used in the photolithography process for forming the projection patterns 21 and the data lines 62, 65 and 66. Therefore, the photoresist patterns 81 and 82 have the same planar shape as the protrusion patterns 61 and the like.

The photoresist patterns 81 and 82 serve to increase the projection, and for this purpose, the photoresist patterns 81 and 82 are preferably set to 10,000 GPa or more. In addition, the photoresist patterns 81 and 82 should have sufficient adhesive strength with the upper and lower layers so as not to fall off in a subsequent chemical vapor deposition process of 300 ° or more. As such photosensitive resin, acrylic resin is generally used.

Next, the driving characteristics of the liquid crystal display using the thin film transistor substrate described above will be described with reference to the drawings.

9 is a cross-sectional view of a liquid crystal display device using a substrate for a liquid crystal display device according to a second embodiment of the present invention.

In the liquid crystal display, the liquid crystal material 300 is vertically aligned between the thin film transistor substrate 10 and the opposing substrate 200, and a polarizer (not shown) is attached to the upper and lower substrates 10 and 200. Has a structure.

A color filter (not shown), a black matrix (not shown), and the like are usually formed on the counter substrate 200 together with the common electrode 210. In this case, since it is not necessary to form an opening pattern or a protrusion in the common electrode 210, various problems caused by patterning the common electrode 210 are eliminated.

When the driving circuit is connected to the liquid crystal display and driven, when the voltage difference between the common electrode 210 and the pixel electrode 91 is less than or equal to the threshold voltage Vth, the liquid crystal molecules 300 do not move but the voltage difference is greater than or equal to Vth. When the liquid crystal molecules 300 start to lie down. The liquid crystal molecules 300 positioned at the periphery of the pixel electrode 91 are inclined toward the center of the pixel electrode by a fringe field, and the liquid crystal molecules 300 on the central protrusion P of the pixel electrode 91. Is inclined toward the center of the pixel electrode 91 similarly to the liquid crystal molecules 300 positioned at the periphery due to the distortion of the electric field direction formed by the projection P. Therefore, a domain is formed around the protrusion. At this time, if the projection P and the pixel electrode 91 are formed in the same shape as in the embodiment of the present invention, four domains each formed at 45 ° in the up, down, left, and right directions are formed. This makes the viewing angle constant up, down, left and right.

If the substrate for a liquid crystal display device is manufactured by the above method, compared with a normal vertical alignment liquid crystal display device, opening pattern and protrusion can be formed and a wide viewing angle can be ensured without adding a process at all, and the common electrode of a top plate is patterned. This eliminates the problem of increasing the common electrode voltage or forming an expensive overcoat film.

Claims (16)

Insulation board, A gate line formed on the insulating substrate, A first protrusion pattern formed of the same material as the gate line on the same layer as the gate line, A data line insulated from and intersecting the gate line; A pixel electrode formed on the first protrusion pattern and overlapping the first protrusion pattern; A switching element which transfers or blocks the image signal transmitted through the data line to the pixel electrode according to a scan signal transmitted through the gate line Substrate for a liquid crystal display device comprising a. In claim 1, And a second protrusion pattern formed of a photosensitive material on the first protrusion pattern and having the same planar shape as the first protrusion pattern. In claim 1, And a common electrode line formed on the same layer as the gate line and made of the same material as the gate line and connected to the first protrusion pattern. The method of claim 1 or 2, The pixel electrode has an opening pattern. In claim 4, The first and second protrusion patterns and the opening patterns of the pixel electrode are symmetrical with each other and are alternately arranged. In claim 5, The first and second protrusion patterns have a shape in which several crosses are vertically connected, and the pixel electrode is divided into a plurality of small regions by the opening pattern, and the first and second protrusion patterns are the pixels. A liquid crystal display substrate for dividing each small region of an electrode into four. Insulation board, A gate line formed on the insulating substrate, A data line insulated from and intersecting the gate line; A first projection pattern formed of the same material as the data line on the same layer as the data line, A pixel electrode formed on the first protrusion pattern and overlapping the first protrusion pattern; A switching element which transfers or blocks the image signal transmitted through the data line to the pixel electrode according to a scan signal transmitted through the gate line Substrate for a liquid crystal display device comprising a. In claim 7, And a second protrusion pattern formed of a photosensitive material on the first protrusion pattern and having the same planar shape as the first protrusion pattern. In claim 7, And a common electrode line formed on the same layer as the gate line and made of the same material as the gate line and overlapping at least a portion of the first protrusion pattern. In claim 7 or 8, The pixel electrode has an opening pattern. In claim 10, The first and second protrusion patterns and the opening patterns of the pixel electrode are symmetrical with each other and are alternately arranged. In claim 11, The projections have a form in which several crosses are vertically connected, the pixel electrode is divided into a plurality of small regions by the opening pattern, and the projections divide each small region of the pixel electrode into four liquid crystal displays. Substrate. First substrate, A gate line formed on the first substrate, A first protrusion pattern formed of the same material as the gate line on the same layer as the gate line, A data line insulated from and intersecting the gate line; A pixel electrode formed on the first protrusion pattern and overlapping the first protrusion pattern and having an opening pattern; A switching element configured to transfer or block an image signal transmitted through the data line to the pixel electrode according to a scan signal transmitted through the gate line; A second substrate facing the first substrate, A common electrode formed on the second substrate and facing the pixel electrode Liquid crystal display comprising a. In claim 13, And a second protrusion pattern formed of a photosensitive material on the first protrusion pattern and having the same planar shape as the first protrusion pattern. First substrate, A gate line formed on the first substrate, A data line insulated from and intersecting the gate line; A first projection pattern formed of the same material as the data line on the same layer as the data line, A pixel electrode formed on the first protrusion pattern and overlapping the first protrusion pattern and having an opening pattern; A switching element configured to transfer or block an image signal transmitted through the data line to the pixel electrode according to a scan signal transmitted through the gate line; A second substrate facing the first substrate, A common electrode formed on the second substrate and facing the pixel electrode Liquid crystal display comprising a. The method of claim 15, And a second protrusion pattern formed of a photosensitive material on the first protrusion pattern and having the same planar shape as the first protrusion pattern.

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