KR101122227B1 - Multi-domain liquid crystal display and a thin film transistor substrate of the same - Google Patents

Abstract

  A gate line formed on the insulation substrate and extending in the horizontal direction, a data line formed on the insulation substrate, insulated from the gate line and intersecting with each other, having a bent portion and a portion extending in the vertical direction, and defined by crossing the gate line and the data line. A first pixel electrode formed for each pixel, a second pixel electrode formed for each pixel, and a thin film transistor connected to the first pixel electrode and capacitively coupled to the first pixel electrode; The second pixel electrode is divided into two and disposed at a position adjacent to the gate line, and the first pixel electrode is disposed between the two second pixel electrodes.

LCD, domain, curved data line, coupling electrode

Description

MULTI-DOMAIN LIQUID CRYSTAL DISPLAY AND A THIN FILM TRANSISTOR SUBSTRATE OF THE SAME

1 is a layout view of a thin film transistor array panel for a liquid crystal display according to a first exemplary embodiment of the present invention.

2 is a layout view of a common electrode display panel of the liquid crystal display according to the first exemplary embodiment of the present invention.

3 is a layout view of a liquid crystal display according to a first exemplary embodiment of the present invention;

4 is a cross-sectional view taken along line IV-IV ′ of FIG. 3,

5 is a circuit diagram of a liquid crystal display according to a first embodiment of the present invention;

6 is a layout view of a liquid crystal display according to a second exemplary embodiment of the present invention.

7 is a layout view of a thin film transistor array panel for a liquid crystal display according to a third exemplary embodiment of the present invention.

8 is a layout view of a common electrode display panel for a liquid crystal display according to a third exemplary embodiment of the present invention.

9 is a layout view of a liquid crystal display according to a third exemplary embodiment of the present invention.

10 is a layout view of a liquid crystal display according to a fourth exemplary embodiment of the present invention.

FIG. 11 is a cross-sectional view taken along line XI-XI ′ of FIG. 10.                 

12 is a layout view of a liquid crystal display according to a fifth exemplary embodiment of the present invention.

13 is a layout view of a liquid crystal display according to a sixth exemplary embodiment of the present invention.

14 is a layout view of a thin film transistor array panel for a liquid crystal display according to a seventh exemplary embodiment of the present invention.

15 is a layout view of a color filter display panel for a liquid crystal display according to a seventh embodiment of the present invention;

16 is a layout view of a liquid crystal display according to a seventh exemplary embodiment of the present invention.

17 is a cross-sectional view taken along the line XVII-XVII ′ of FIG. 16,

18 is a layout view of a liquid crystal display according to an eighth exemplary 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 more particularly, to a vertically aligned liquid crystal display device in which a pixel is divided into a plurality of domains in order to obtain a wide viewing angle.

In general, a liquid crystal display device injects a liquid crystal material between an upper substrate on which a common electrode and a color filter 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. To overcome these shortcomings, 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 constant incision pattern or protrusions are formed on the pixel electrode and the common electrode as the opposite electrode. The method is influential.

In such a multi-domain liquid crystal display, the gray scale inversion reference viewing angle defined as a contrast ratio reference viewing angle based on a contrast ratio of 1:10 or a limit angle of luminance inversion between gray scales is excellent, more than 80 ° in all directions. However, a side gamma curve distortion phenomenon occurs in which the front gamma curve and the side gamma curve do not coincide with each other, thereby inferior visibility in the left and right sides compared to the TN (twisted nematic) mode liquid crystal display. For example, in the patterned vertically aligned (PVA) mode, which makes an incision by domain dividing means, the screen looks brighter and the color tends to shift toward white as the side faces. Occasionally, the picture appears clumped and disappears. However, as liquid crystal display devices are used for multimedia in recent years, visibility has become increasingly important as pictures and moving pictures are viewed.

On the other hand, in the method of forming a protrusion or a cutout pattern, the opening ratio is lowered due to the protrusion or the cutout pattern portion. In order to compensate for this, an ultra-high-aperture structure that forms the pixel electrode as wide as possible has been devised. However, since the distance between adjacent pixel electrodes is very close, a lateral field formed between the pixel electrodes is strongly formed. Therefore, the liquid crystals positioned at the edges of the pixel electrodes are affected by the lateral electric field, and thus the alignment is disturbed, resulting in texture or light leakage.

The technical problem to be achieved by the present invention is to implement a multi-domain liquid crystal display device having excellent visibility.

Another object of the present invention is to provide a liquid crystal display device which forms a stable multiple domain.

Another object of the present invention is to improve the aperture ratio of a multi-domain liquid crystal display.

In order to solve this problem, the present invention provides the following thin film transistor array panel and liquid crystal display device.

An insulation substrate, a first signal line formed on the insulation substrate and extending in a first direction, the first signal line formed on the insulation substrate, insulated from and intersecting the first signal line, and having a bent portion and a portion extending in the second direction. A first pixel electrode formed for each pixel defined by the intersection of the second signal line, the first signal line and the second signal line, a second pixel electrode formed for each pixel and capacitively coupled to the first pixel electrode; A thin film transistor connected to the first signal line and the second signal line, and connected to any one of the first pixel electrode and the second pixel electrode, wherein the second pixel electrode is divided into two and the first signal line; A thin film disposed at a position adjacent to the signal line, wherein the first pixel electrode is disposed between the two second pixel electrodes Establish a transistor panel.

At this time, the bent portion of the second signal line includes two straight portions, one of the two straight portions forms substantially 135 degrees with respect to the first signal line and the other substantially with respect to the first signal line. Preferably, the thin film transistor may further include a coupling electrode connected to the first pixel electrode, connected to the first pixel electrode, and overlapping the second pixel electrode in an insulated state. have.

The thin film transistor may further include a coupling electrode connected to the second pixel electrode and connected to the second pixel electrode and overlapping the first pixel electrode in an insulated state. The two pixel electrodes may be divided into two parts, and a portion substantially forming 135 degrees with respect to the first signal line and a portion substantially forming 45 degrees with respect to the first signal line.

The display device may further include a storage electrode line formed to be parallel to the gate line, and a storage electrode connected to the storage electrode line and at least partially overlapping the coupling electrode.

Or a first signal line formed on the first insulating substrate, the first signal line formed on the first insulating substrate, a second signal line formed on the first insulating substrate, insulated from and intersecting the first signal line, and having a refractive portion; A first pixel electrode formed for each pixel defined by the intersection of the second signal line and a second pixel electrode formed for each pixel and capacitively coupled to the first pixel electrode, the first signal line, and the first pixel electrode; A thin film transistor connected to two signal lines and connected to any one of the first pixel electrode and the second pixel electrode, a second insulating substrate facing the first insulating substrate, and formed on the second insulating substrate. Common electrode, domain dividing means formed on the second insulating substrate, and injected between the first insulating substrate and the second insulating substrate. And a first layer, wherein the first and second pixels are divided into a plurality of domains by the domain dividing means, and two long sides of the domain are substantially parallel with the refraction portion of the adjacent second signal line, and the second pixel An electrode is divided into two and disposed at a position adjacent to the first signal line, and the first pixel electrode is disposed between two second pixel electrodes.

In this case, it is preferable that the liquid crystal contained in the liquid crystal layer has negative dielectric anisotropy, and the liquid crystal has its long axis oriented perpendicular to the first and second substrates, and the domain dividing means includes the common electrode. This branch may be an incision.

DETAILED DESCRIPTION Embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a part of a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the other part being "right over" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

Next, a multi-domain liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to the drawings.

1 is a layout view of a thin film transistor array panel for a liquid crystal display according to a first embodiment of the present invention, FIG. 2 is a layout view of a common electrode display panel of a liquid crystal display according to a first embodiment of the present invention, and FIG. 4 is a layout view of the liquid crystal display according to the first exemplary embodiment, and FIG. 4 is a cross-sectional view taken along line IV-IV 'of FIG. 3.

The liquid crystal display according to the first exemplary embodiment of the present invention is a liquid crystal molecule injected into and included between the thin film transistor array panel 100, the common electrode panel 200 facing the thin film transistor panel 100, and the two display panels 100 and 200. The major axis of is made of the liquid crystal layer 3 oriented perpendicular to the display panels 100 and 200.

First, the thin film transistor array panel 100 will be described in more detail with reference to FIGS. 1, 4, and 5.

The gate line 121 is formed in the horizontal direction on the insulating substrate 110, and the gate electrode 123 is connected to the gate line 121. One end 125 of the gate line 121 is extended in width for connection with an external circuit.                     

The storage electrode line 131 and the storage electrode 133 are formed on the insulating substrate 110. The storage electrode line 131 extends in the horizontal direction, and the storage electrode 133 extends in a direction of 135 degrees with respect to the storage electrode line 131, and is extended by a predetermined length by bending 90 degrees.

The gate wirings 121, 123, and 125 and the sustain electrode wirings 131 and 133 are formed of a double layer of a lower layer made of Cr or Mo alloy having excellent physicochemical properties or the like and an upper layer made of Al or Ag alloy having a low resistance. It is preferable. These gate wirings 121, 123, 125 and sustain electrode wirings 131, 133 may be formed in a single layer or triple layers or more as needed.

The gate insulating layer 140 is formed on the gate wirings 121, 123, and 125 and the storage electrode wirings 131 and 133.

The semiconductor layers 151, 154, and 156 made of a semiconductor such as amorphous silicon are formed on the gate insulating layer 140. The semiconductor layers 151, 154, and 156 may be formed under the channel portion semiconductor layer 154 and the data line portion semiconductor layer 151 and the coupling electrode 176 positioned under the data line 171 to form a channel of the thin film transistor. The coupling electrode unit semiconductor layer 156 is positioned.

On the semiconductor layers 151, 154, and 156, ohmic contacts 161, 163, 165, and 166 made of a material such as n + hydrogenated amorphous silicon doped with silicide or n-type impurities at a high concentration are formed. The ohmic contacts 161, 163, 165, and 166 also have a data line contact layer 161 positioned below the data line, and a source contact layer 163 positioned below the source electrode 173 and the drain electrode 175, respectively. And a drain contact layer 165 and a coupling electrode part semiconductor layer 156.

Data lines 171, 173, 175, and 179 are formed on the ohmic contacts 161, 163, and 165 and the gate insulating layer 140. The data lines 171, 173, 175, and 179 extend long and cross the gate line 121 to branch the data line 171 and the data line 171 to define a pixel, and to the upper portion of the ohmic contact layer 163. An extended source electrode 173 and a drain electrode 175 separated from the source electrode 173 and formed on the ohmic contact layer 165 opposite to the source electrode 173 with respect to the gate electrode 123. have. One end 179 of the data line 171 is extended in width to connect to an external circuit.

Here, the data line 171 is formed such that the repeatedly bent portion and the vertically extending portion appear with a length of the pixel. At this time, the curved portion of the data line 171 consists of two straight portions, one of the two straight portions forms 135 degrees with respect to the gate line 121, and the other portion is formed on the gate line 121. At 45 degrees. The source electrode 173 is connected to a vertically extending portion of the data line 171, and the portion crosses the gate line 121 and the storage electrode line 131.

At this time, the ratio of the lengths of the bent portion and the vertically extending portion of the data line 171 is between 1: 1 and 9: 1 (that is, the ratio of the bent portion of the data line 171 is between 50% and 90%). )to be.

Therefore, the pixel formed by the intersection of the gate line 121 and the data line 171 is formed in a band shape.

Meanwhile, a coupling electrode 176 made of the same material is connected to the drain electrode 175 in the same layer as the drain electrode 175. The coupling electrode 176 extends in the horizontal direction from the drain electrode 175 and is bent to form parallel to the curved portion of the data line 171. In other words, at the portion connected to the drain electrode 175, it is parallel to the gate line 121 and then bent once to proceed in a direction of 135 degrees with respect to the gate line 121, and is bent once again to be 45 degrees with respect to the gate line 121. It extends by a predetermined distance in the direction of forming.

A passivation layer 180 made of an organic insulating layer is formed on the data lines 171, 173, 175, and 179 and the coupling electrode 176. The passivation layer 180 is formed by exposing and developing the photosensitive organic material. If necessary, the passivation layer 180 may be formed by applying a photosensitive organic material and performing a photolithography process, but the forming process is more complicated than forming the passivation layer 180 using the photosensitive organic material.

In the passivation layer 180, a contact hole 181 exposing the drain electrode and a contact hole 182 exposing the end portion 179 of which the width of the data line is extended are formed. In addition, the contact hole 183 passes through the gate insulating layer 140 together with the passivation layer 180 to expose the end portion 129 where the width of the gate line is extended.

At this time, the sidewalls of these contact holes 181, 182, 183 preferably have a gentle slope between 30 degrees and 85 degrees with respect to the substrate surface, or have a stepped profile.                     

In addition, these contact holes 1810, 182, 183 can be formed in various shapes such as polygons or circles, the area is not more than 2mm × 60㎛, preferably 0.5mm × 15㎛ or more.

Meanwhile, the passivation layer 180 may be formed of an inorganic insulating material such as silicon nitride or silicon oxide.

A first pixel electrode 190a and a second pixel electrode 190b are formed on the passivation layer 180 in a band shape that is bent along the shape of the pixel, and have the cutouts 191 and 192 in the horizontal direction, respectively. The first pixel electrode 190a and the second pixel electrode 190b have substantially the same shape, and occupy the left and right pixels. Therefore, when the first pixel electrode 190a is moved parallel to the predetermined distance along the gate line 121, the first pixel electrode 190a coincides with the second pixel electrode 190b.

The first pixel electrode 190a is connected to the drain electrode 175 through the contact hole 181. Although the second pixel electrode 190b is in an electrically floating state, the second pixel electrode 190b overlaps the coupling electrode 176 connected to the drain electrode 175 and is capacitively coupled to the first pixel electrode 190a. That is, the voltage of the second pixel electrode 190b is in a state in which the voltage applied to the first pixel electrode 190a varies. At this time, the voltage of the second pixel electrode 190b is always lower than the voltage of the first pixel electrode 190a.

As such, when two pixel electrodes having different voltages are disposed in one pixel area, the two pixel electrodes compensate for each other to reduce distortion of the gamma curve. The coupling relationship between the first pixel electrode 190a and the second pixel electrode 190b will be described in detail later with reference to FIG. 5.

In addition, contact auxiliary members 95 and 97 are formed on the passivation layer 180 and are connected to the end portion 125 of the gate line and the end portion 179 of the data line through contact holes 182b and 183b, respectively. The pixel electrodes 190a and 190b and the contact assistants 95 and 97 are made of indium tin oxide (ITO) or indium zinc oxide (IZO).

Next, the common electrode display panel will be described with reference to FIGS. 2, 4, and 5.

On the lower surface of the upper substrate 210 made of a transparent insulating material such as glass, a black matrix 220 and red, green, and blue color filters 230 are formed to prevent light leakage. An overcoat film 250 made of an organic material is formed. On the overcoat layer 250, a common electrode 270 made of a transparent conductive material such as ITO or IZO and having a cutout 271 is formed.

At this time, the cutout 271 acts as a domain regulating means, and the width thereof is preferably between 9 µm and 12 µm. In the case of forming the organic protrusions instead of the cutouts 271 by the domain regulating means, it is preferable to set the width between 5 μm and 10 μm.

The color filter 230 is formed vertically long along the pixel column defined by the black matrix 220, and is periodically bent along the shape of the pixel.

Two cutouts 271 and 272 of the common electrode 270 are disposed for each pixel and bent along the shape of the pixel, and each cutout 271 and 272 is formed of the first pixel electrode 190a and the first cutout. The two pixel electrodes 190b are formed at positions that bisect left and right, respectively. Both ends of the cutouts 271 and 272 are bent once again and extend by a predetermined length in parallel with the gate line 121. The center portion of the cutouts 271 and 272 also extends by a predetermined length in parallel with the gate line 121, but extends in opposite directions to both ends of the cutouts 271 and 272.

When the liquid crystal layer 3 is formed by combining the thin film transistor array panel and the common electrode display panel having the above structure and injecting liquid crystal therebetween, a basic panel of the liquid crystal display according to the first embodiment of the present invention is formed.

The liquid crystal molecules included in the liquid crystal layer 3 have directors with respect to the lower substrate 110 and the upper substrate 210 when no electric field is applied between the pixel electrodes 190a and 190b and the common electrode 270. It is oriented perpendicularly and has negative dielectric anisotropy. The lower substrate 110 and the upper substrate 210 are aligned such that the pixel electrode 190 accurately overlaps the color filter 230. In this way, the pixel is divided into a plurality of domains by the first and second pixel electrodes 190a and 190b and the cutouts 271 and 272. At this time, the first and second pixel electrodes 190a and 190b are divided into left and right sides by the cutouts 271 and 272, and are divided into four types of domains.

At this time, the distance between the two long sides of the domain, that is, the width of the domain is preferably between 10㎛ 30㎛.

The liquid crystal display device is formed by disposing elements such as polarizing plates 12 and 22, a backlight, and compensation plates 13 and 23 on both sides of the basic panel. At this time, the polarizing plates 12 and 22 are disposed on both sides of the basic panel, respectively, and the transmission axis thereof is disposed so that one of them is parallel to the gate line 121 and the other is perpendicular to the gate line 121.

When the liquid crystal display device is formed as described above, when an electric field is applied to the liquid crystal, the liquid crystal in each domain is inclined in a direction perpendicular to the long side of the domain. However, since the direction is perpendicular to the data line 171, the direction coincides with the direction in which the liquid crystal is inclined by the lateral electric field formed between two adjacent pixel electrodes 190 with the data line 171 therebetween. As a result, the lateral electric field assists the liquid crystal alignment of each domain.

Since the liquid crystal display generally uses inversion driving methods such as point inversion driving, thermal inversion driving, and two-point inversion driving, which apply voltages having opposite polarities to pixel electrodes positioned on both sides of the data line 171, the lateral electric field is Almost always occurs and the direction is the direction that helps the liquid crystal alignment of the domain.

In addition, since the transmission axis of the polarizing plate is disposed in a direction perpendicular to or parallel to the gate line 121, the polarizing plate can be manufactured at low cost, and the alignment direction of the liquid crystal is 45 degrees with the transmission axis of the polarizing plate in all domains, thereby obtaining the highest luminance. Can be.

However, since the length of the wiring increases because the data line 171 is bent, the length of the wiring increases by about 20% when the bent portion of the data line 171 occupies 50%. When the length of the data line 171 increases, the resistance and the load of the wiring increase, thereby increasing the signal distortion. However, in the ultra-high opening ratio structure, the width of the data line 171 can be formed sufficiently wide, and since the thick organic protective film 180 is used, the load of the wiring is also small enough so that the signal distortion problem due to the increase in the length of the data line 171 can be ignored. Can be.

Meanwhile, in the liquid crystal display having the structure, the first pixel electrode 190a receives an image signal voltage through the thin film transistor, whereas the second pixel electrode 190b is formed by capacitive coupling with the coupling electrode 176. Because of this variation, the absolute value of the voltage of the second pixel electrode 190b is always lower than that of the first pixel electrode 190a. As such, when two pixel electrodes 190a and 190b having different voltages are disposed in one pixel, the two pixel electrodes 190a and 190b compensate for each other to reduce distortion of the gamma curve.

Next, the reason why the voltage of the first pixel electrode 190a is lower than the voltage of the second pixel electrode 190b will be described with reference to FIG. 5.

5 is a circuit diagram illustrating a liquid crystal display according to a first exemplary embodiment of the present invention.

In FIG. 5, Clca represents a liquid crystal capacitance formed between the first pixel electrode 190a and the common electrode 270, and Cst represents a retention formed between the first pixel electrode 190a and the sustain electrode wirings 131 and 133. Capacity. Clcb represents a liquid crystal capacitor formed between the second pixel electrode 190b and the common electrode 270, and Ccp represents a coupling capacitor formed between the first pixel electrode 190a and the second pixel electrode 190b.

When the voltage of the first pixel electrode 190a with respect to the voltage of the common electrode 270 is called Va, and the voltage of the second pixel electrode 190b is called Vb, according to the voltage division law,                     

Va = Vb × [Ccp / (Ccp + Clcb)]

Since Ccp / (Ccp + Clcb) is always less than 1, Vb is always smaller than Va. The ratio of Vb to Va can be adjusted by adjusting Ccp. The adjustment of Ccp is possible by adjusting the overlapping area or distance of the coupling electrode 176 and the second pixel electrode 190b. The overlapping area can be easily adjusted by changing the width of the coupling electrode 176, and the distance can be adjusted by changing the formation position of the coupling electrode 176. That is, in the exemplary embodiment of the present invention, the coupling electrode 176 is formed on the same layer as the data line 171, but the coupling electrode 176 and the second pixel electrode 190b are formed on the same layer as the gate line 121. You can increase the distance between them.

The arrangement of the coupling electrode 176 may be variously modified. One example thereof will be described as the second embodiment.

Hereinafter, only the features distinguished from the first embodiment will be described, and the rest of the description will be omitted.

6 is a layout view of a liquid crystal display according to a second exemplary embodiment of the present invention.

Compared to the first embodiment, in the second embodiment, the positions of the first pixel electrode 190a and the second pixel electrode 190b are exchanged with each other. Accordingly, the positions of the coupling electrode 176 and the storage electrode 133 are also changed. Exchanged with each other. That is, in the first exemplary embodiment, the first pixel electrode 190a and the storage electrode 133 positioned to the right of the pixel move to the left of the pixel, whereas the second pixel electrode 190b and the coupling electrode 176 to the left of the pixel. Moved to the right.

On the other hand, when the ratio of the lengths of the bent portion and the vertically extending portion of the data line 171 is different, the shape of the pixel is also different. A case in which the length of the vertically extending portion is substantially increased will be described as the third embodiment.

7 is a layout view of a thin film transistor array panel for a liquid crystal display according to a third exemplary embodiment of the present invention. FIG. 8 is a layout view of a common electrode display panel for a liquid crystal display according to a third exemplary embodiment of the present invention. A layout view of a liquid crystal display according to a third exemplary embodiment of the invention.

In the third embodiment, the length of the vertically extending portion of the data line 171 is increased to have a rectangular portion connected to the upper and lower ends of the band portion where the pixel is bent and the band portion that is bent. At this time, it is preferable that the length of the vertically extending part is larger than the length of the bent part. Therefore, the shapes of the pixel electrodes 190a and 190b are also modified to maximize the area of the pixel. That is, both ends of the first pixel electrode 190a are adjacent to the vertically extending portion of the data line 171, and both ends of the second pixel electrode 190b are adjacent to the gate line 121. . In addition, the widths of the upper and lower ends of the second pixel electrode 190b are extended to fill the remaining area of the pixel.

The storage electrode 133 and the coupling electrode 176 are respectively positioned to overlap with the center portions of the first pixel electrode 190a and the second pixel electrode 190b.

The cutouts 271 and 272 of the common electrode 270 are formed to overlap the sustain electrode 133 and the coupling electrode 176. At this time, both ends of the cutout 271 is bent once more to extend along the gate line 121 by a predetermined length, and both ends of the cutout 272 are bent once more to be parallel to the data line 171. It extends by a predetermined length. The centers of the two cutouts 271 and 272 also extend by a predetermined length in parallel with the gate line 121, but extend in opposite directions to both ends of the cutout 271.

Such a structure is intended to alleviate the phenomenon that characters are broken when displaying characters, etc., because the pixels are formed in a band shape.

In the first to third embodiments described above, the ohmic contact layers 161, 163, 165, and 166 are formed under the data wires 171, 173, 175, and 179 and the coupling electrode 176. , 175, 179, and coupling electrode 176 in substantially the same planar pattern, and the amorphous silicon layers 151, 154, and 156 also have data lines 171, 173, and 175 in the region except for the channel portion 154. 179 and the coupling electrode 176 are formed in substantially the same planar pattern.

These structural features include three steps of thickness of the amorphous silicon layers 151, 154, 156, the ohmic contact layers 161, 163, 165, 166, the data lines 171, 173, 175, and 179 and the coupling electrode 176. It comes from forming by patterning together using a single photosensitive film pattern separated by.

Using this method, a thin film transistor array panel of a liquid crystal display device can be manufactured using only four optical masks. That is, when forming the gate wiring and the sustain electrode wiring, the first sheet, the gate insulating film, the amorphous silicon layer, the ohmic contact layer, and the data metal layer after deposition, the second silicon, protective film and the protective film when patterning the amorphous silicon layer, the ohmic contact layer and the data metal layer. The third sheet, the pixel electrode, and the fourth sheet are formed when the contact hole is formed. In this case, the second sheet photomask includes a portion (a slit pattern or a translucent film) that transmits only a portion of the light in addition to a portion that transmits all the light and a portion that blocks the light, and a portion that transmits only the light is located in the channel portion. .

However, the thin film transistor array panel for the liquid crystal display according to the present invention may be manufactured using five optical masks. Hereinafter, a liquid crystal display using a thin film transistor array panel manufactured using five optical masks will be described as the fourth to sixth embodiments.

FIG. 10 is a layout view of a liquid crystal display according to a fourth exemplary embodiment of the present invention, and FIG. 11 is a cross-sectional view taken along line XI-XI ′ of FIG. 10.

In the liquid crystal display according to the fourth exemplary embodiment, the patterns of the semiconductor layers 151 and 154 and the ohmic contact layers 161, 163, and 165 may include the data lines 171, 173, 175, and 179 and the coupling electrode 176. ), Which is different from the liquid crystal display according to the first embodiment.

That is, the data line semiconductor layer 151 formed under the data line 171 is formed to have a smaller width than the data line 171, and no semiconductor layer is formed under the coupling electrode 176. Similar to the semiconductor layer 151, the data line contact layer 161 is formed to have a smaller width than the data line 171, and is not formed below the coupling electrode 176.

This structure forms the semiconductor layers 151 and 154 and the ohmic contact layers 161, 163 and 165 together by a photolithography process, and separates the data lines 171, 173 and 175 and the coupling electrode 176 thereon. It is because it is formed by a photolithography process. In other words, the semiconductor layer, the ohmic contact layer, and the data wiring and the coupling electrode which are formed using only one optical mask in the first embodiment are structural differences that appear because the second embodiment is formed by using two optical masks. .

12 is a layout view of a liquid crystal display according to a fifth exemplary embodiment of the present invention.

In the liquid crystal display according to the fifth exemplary embodiment, the patterns of the semiconductor layers 151 and 154 and the ohmic contact layers 161, 163, and 165 may include the data lines 171, 173, 175, and 179 and the coupling electrode 176. ), Which is different from the liquid crystal display according to the second embodiment.

That is, the data line semiconductor layer 151 formed under the data line 171 is formed to have a smaller width than the data line 171, and no semiconductor layer is formed under the coupling electrode 176. Similar to the semiconductor layer 151, the data line contact layer 161 is formed to have a smaller width than the data line 171, and is not formed below the coupling electrode 176.

This is a structural difference that appears because the semiconductor layer, the ohmic contact layer, and the data wiring and the coupling electrode formed using only one optical mask in the second embodiment are formed using two optical masks in the fifth embodiment. .

13 is a layout view of a liquid crystal display according to a sixth exemplary embodiment of the present invention.

In the liquid crystal display according to the sixth exemplary embodiment, the patterns of the semiconductor layers 151 and 154 and the ohmic contact layers 161, 163, and 165 may include the data lines 171, 173, 175, and 179 and the coupling electrode 176. ), Which is different from the liquid crystal display according to the third embodiment.

That is, the data line semiconductor layer 151 formed under the data line 171 is formed to have a smaller width than the data line 171, and no semiconductor layer is formed under the coupling electrode 176. Similar to the semiconductor layer 151, the data line contact layer 161 is formed to have a smaller width than the data line 171, and is not formed below the coupling electrode 176.

This is a structural difference that appears because the semiconductor layer, the ohmic contact layer, and the data wiring and the coupling electrode, which are formed using only one optical mask in the third embodiment, are formed by using two optical masks in the sixth embodiment. .

In the present invention, various modifications may be made to the method of arranging the first pixel electrode 190a and the second pixel electrode 190b. Two examples thereof will be described as the seventh and eighth embodiments.

FIG. 14 is a layout view of a thin film transistor array panel for a liquid crystal display according to a seventh embodiment of the present invention. FIG. 15 is a layout view of a color filter display panel for a liquid crystal display according to a seventh embodiment of the present invention. FIG. 17 is a layout view of a liquid crystal display according to a seventh exemplary embodiment, and FIG. 17 is a cross-sectional view taken along line XVII-XVII ′ of FIG. 16.

In the liquid crystal display according to the seventh exemplary embodiment of the present invention, the thin film transistor array panel 100 and the common electrode panel 200 facing each other and the liquid crystal molecules injected between and included in the two display panels 100 and 200 are included. The major axis of is made of the liquid crystal layer 3 oriented perpendicular to the display panels 100 and 200.                     

First, the thin film transistor array panel 100 will be described in more detail with reference to FIGS. 14, 16, and 17.

The gate line 121 is formed in the horizontal direction on the insulating substrate 110, and the gate electrode 123 is connected to the gate line 121. One end 125 of the gate line 121 is extended in width for connection with an external circuit.

The storage electrode line 131 and the storage electrode 133 are formed on the insulating substrate 110. The storage electrode line 131 extends in the horizontal direction, and the storage electrode 133 is formed in a form in which the width of the storage electrode line 131 is partially extended.

The gate wirings 121, 123, and 125 and the sustain electrode wirings 131 and 133 are formed of a double layer of a lower layer made of Cr or Mo alloy having excellent physicochemical properties or the like and an upper layer made of Al or Ag alloy having a low resistance. It is preferable. These gate wirings 121, 123, 125 and sustain electrode wirings 131, 133 may be formed in a single layer or triple layers or more as needed.

The gate insulating layer 140 is formed on the gate wirings 121, 123, and 125 and the storage electrode wirings 131 and 133.

The semiconductor layers 151, 154, and 156 made of a semiconductor such as amorphous silicon are formed on the gate insulating layer 140. The semiconductor layers 151, 154, and 156 may be formed under the channel portion semiconductor layer 154 and the data line portion semiconductor layer 151 and the coupling electrode 176 positioned under the data line 171 to form a channel of the thin film transistor. The coupling electrode unit semiconductor layer 156 is positioned.                     

On the semiconductor layers 151, 154, and 156, ohmic contacts 161, 163, 165, and 166 made of a material such as n + hydrogenated amorphous silicon doped with silicide or n-type impurities at a high concentration are formed. The ohmic contacts 161, 163, 165, and 166 also have a data line contact layer 161 positioned below the data line, and a source contact layer 163 positioned below the source electrode 173 and the drain electrode 175, respectively. And a drain contact layer 165 and a coupling electrode part semiconductor layer 156.

Data lines 171, 173, 175, and 179 are formed on the ohmic contacts 161, 163, and 165 and the gate insulating layer 140. The data lines 171, 173, 175, and 179 extend long and cross the gate line 121 to branch the data line 171 and the data line 171 to define a pixel, and to the upper portion of the ohmic contact layer 163. An extended source electrode 173 and a drain electrode 175 separated from the source electrode 173 and formed on the ohmic contact layer 165 opposite to the source electrode 173 with respect to the gate electrode 123. have. One end 179 of the data line 171 is extended in width to connect to an external circuit.

Here, the data line 171 is formed such that the repeatedly bent portion and the vertically extending portion appear with a length of the pixel. At this time, the curved portion of the data line 171 consists of two straight portions, one of the two straight portions forms 135 degrees with respect to the gate line 121, and the other portion is formed on the gate line 121. At 45 degrees. The source electrode 173 is connected to a vertically extending portion of the data line 171, and the portion crosses the gate line 121 and the storage electrode line 131.                     

At this time, the ratio of the lengths of the bent portion and the vertically extending portion of the data line 171 is between 1: 1 and 9: 1 (that is, the ratio of the bent portion of the data line 171 is between 50% and 90%). )to be.

Therefore, the pixel formed by the intersection of the gate line 121 and the data line 171 is formed in a band shape.

Meanwhile, a coupling electrode 176 made of the same material is connected to the drain electrode 175 in the same layer as the drain electrode 175. The coupling electrode 176 is bent from the drain electrode 175 and formed in parallel with the curved portion of the data line 171. That is, at a portion connected to the drain electrode 175, the electrode is bent once and proceeds in the direction of 135 degrees with respect to the gate line 121, and is bent once again and extends by a predetermined distance in the direction of 45 degrees with respect to the gate line 121. It is.

In addition, the width of the coupling electrode 176 extends at a portion overlapping the sustain electrode 133. This is to widen the overlapping area with the storage electrode 133 to form a sufficient storage capacitor and to secure a contact area with the first pixel electrode 190a.

A passivation layer 180 made of an organic insulating layer is formed on the data lines 171, 173, 175, and 179 and the coupling electrode 176. The passivation layer 180 is formed by exposing and developing the photosensitive organic material. If necessary, the passivation layer 180 may be formed by applying a photosensitive organic material and performing a photolithography process, but the forming process is more complicated than forming the passivation layer 180 using the photosensitive organic material.

The passivation layer 180 is formed with a contact hole 181 exposing an extended portion of the coupling electrode 176 and a contact hole 182 exposing an end portion 179 having an extended width of the data line. In addition, the contact hole 183 passes through the gate insulating layer 140 together with the passivation layer 180 to expose the end portion 129 where the width of the gate line is extended.

At this time, the sidewalls of these contact holes 181, 182, 183 preferably have a gentle slope between 30 degrees and 85 degrees with respect to the substrate surface, or have a stepped profile.

In addition, these contact holes 1810, 182, 183 can be formed in various shapes such as polygons or circles, the area is not more than 2mm × 60㎛, preferably 0.5mm × 15㎛ or more.

Meanwhile, the passivation layer 180 may be formed of an inorganic insulating material such as silicon nitride or silicon oxide.

Upper and lower portions of the first pixel electrode 190a and the first pixel electrode 190a having upper and lower centers on the passivation layer 180 and having a band shape bent along the shape of the pixel and having a cutout 191 in a horizontal direction. The parallelogram second pixel electrode 190b is formed in two parts. The first pixel electrode 190a and the second pixel electrode 190b occupy substantially the same area in each pixel.

The first pixel electrode 190a is connected to the coupling electrode 176 through the contact hole 181. Although the second pixel electrode 190b is electrically floating, the second pixel electrode 190b overlaps the coupling electrode 176 and is capacitively coupled to the first pixel electrode 190a. That is, the voltage of the second pixel electrode 190b is in a state in which the voltage applied to the first pixel electrode 190a varies. At this time, the voltage of the second pixel electrode 190b is always lower than the voltage of the first pixel electrode 190a. Therefore, a high voltage is applied to the center of the stroke in the pixel, and a voltage slightly lower than the center of gravity is applied to both ends of the curve.

In the present exemplary embodiment, the coupling electrode 176 serves as a path of an image signal transmitted through the thin film transistor in addition to capacitively coupling the first pixel electrode 190a and the second pixel electrode 190b.

As such, when two pixel electrodes having different voltages are disposed in one pixel area, the two pixel electrodes compensate for each other to reduce distortion of the gamma curve.

In addition, contact auxiliary members 95 and 97 are formed on the passivation layer 180 and are connected to the end portion 125 of the gate line and the end portion 179 of the data line through contact holes 182b and 183b, respectively. The pixel electrode 190 and the contact assistants 95 and 97 are made of indium tin oxide (ITO) or indium zinc oxide (IZO).

The common electrode display panel will now be described with reference to FIGS. 15, 16, and 17.

On the lower surface of the upper substrate 210 made of a transparent insulating material such as glass, a black matrix 220 and red, green, and blue color filters 230 are formed to prevent light leakage. An overcoat film 250 made of an organic material is formed. On the overcoat layer 250, a common electrode 270 made of a transparent conductive material such as ITO or IZO and having a cutout 271 is formed.

At this time, the cutout 271 acts as a domain regulating means, and the width thereof is preferably between 9 µm and 12 µm. In the case of forming the organic protrusions instead of the cutouts 271 by the domain regulating means, it is preferable to set the width between 5 μm and 10 μm.

The color filter 230 is formed vertically long along the pixel column defined by the black matrix 220, and is periodically bent along the shape of the pixel.

The cutout 271 of the common electrode 270 is bent along the shape of the pixel, and the cutout 271 is formed at a position that bisects the first pixel electrode 190a and the second pixel electrode 190b from side to side. . Both ends of the cutout 271 is bent once more and extend by a predetermined length in parallel with the gate line 121. The center portion of the cutout 271 also extends by a predetermined length in parallel with the gate line 121, but extends in opposite directions to both ends of the cutout 271. Branch cutouts protruding from side to side are also formed at the 1/4 and 3/4 points of the cutout 271.

When the liquid crystal layer 3 is formed by combining the thin film transistor array panel and the common electrode display panel having the above structure and injecting liquid crystal therebetween, a basic panel of the liquid crystal display according to the first embodiment of the present invention is formed.

The liquid crystal molecules included in the liquid crystal layer 3 have directors with respect to the lower substrate 110 and the upper substrate 210 when no electric field is applied between the pixel electrodes 190a and 190b and the common electrode 270. It is oriented perpendicularly and has negative dielectric anisotropy. The lower substrate 110 and the upper substrate 210 are aligned such that the pixel electrode 190 accurately overlaps the color filter 230. In this way, the pixel is divided into a plurality of domains by the first and second pixel electrodes 190a and 190b and the cutout 271. In this case, the first and second pixel electrodes 190a and 190b are divided into left and right sides by the cutouts 271, and are also divided into four types of domains.

The liquid crystal display device is formed by disposing elements such as polarizing plates 12 and 22, a backlight, and compensation plates 13 and 23 on both sides of the basic panel. In this case, the polarizing plates 12 and 22 are disposed on both sides of the basic panel, respectively, and the transmission axis thereof is disposed so that one of them is parallel to the gate line 121 and the other is perpendicular to the gate line 121.

When the liquid crystal display device is formed as described above, when an electric field is applied to the liquid crystal, the liquid crystal in each domain is inclined in a direction perpendicular to the long side of the domain. However, since this direction is perpendicular to the data line 171, the direction coincides with the direction in which the liquid crystal is inclined by the lateral electric field formed between two adjacent pixel electrodes 190a 190b with the data line 171 therebetween. As a result, the lateral electric field assists the liquid crystal alignment of each domain.

In addition, since the transmission axis of the polarizing plate is disposed in a direction perpendicular to or parallel to the gate line 121, the polarizing plate can be manufactured at low cost, and the alignment direction of the liquid crystal is 45 degrees with the transmission axis of the polarizing plate in all domains, thereby obtaining the highest luminance. Can be.

Meanwhile, by disposing two pixel electrodes 190a and 190b having different voltages in one pixel, the distortion of the gamma curve may be compensated for and reduced.

18 is a layout view of a liquid crystal display according to an eighth exemplary embodiment of the present invention.                     

Compared to the seventh embodiment, in the eighth embodiment, the positions of the first pixel electrode 190a and the second pixel electrode 190b are exchanged with each other, whereby the width and width of the coupling electrode 176 are extended. The position of the electrode 133 is changed. That is, in the seventh embodiment, the first pixel electrode 190a, which is positioned at the center of the pixel, is divided into two and positioned above and below the pixel. On the contrary, the second pixel electrode 190b is arranged to be bent at the center of the pixel. In addition, the coupling electrode 176 has two portions of which the width is extended to connect with the first pixel electrode 190a which is divided into two upper and lower sides.

The seventh and eighth exemplary embodiments illustrate a thin film transistor array panel manufactured using four photomasks, but the thin film transistor array panel manufactured using five photomasks may also be applied. It will be easily understood through the sixth embodiment.

In the first to eighth embodiments of the present invention, as an example of the liquid crystal display device according to the present invention, the incision is formed in the common electrode to divide the domain. Alternatively, the domain may be formed by forming the organic film protrusion on the common electrode. Do. That is, the organic film protrusion may be used instead of the cutout as the domain dividing means. In this case, the planar pattern of the organic film protrusion may be formed in the same manner as the planar pattern of the cutout.

Further, in the first to eighth embodiments, the color filter is formed on the common electrode substrate as an example of the liquid crystal display according to the present invention. Alternatively, the color filter may be formed between the passivation layer and the pixel electrode of the thin film transistor substrate. It may be.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

As described above, when the data lines are refracted to form pixels in an angled band shape, the lateral electric field between adjacent pixels acts in a direction to assist the formation of the domains, thereby stably forming the domains. Since the polarizers can be manufactured inexpensively, the alignment directions of the liquid crystals are 45 degrees with the transmission axis of the polarizers in all domains, so that the highest luminance can be obtained.

In addition, the viewing angle can be extended by improving the side visibility of the liquid crystal display through the above configuration.

Claims (9)

Insulation board, A first signal line formed on the insulating substrate and extending in a first direction, A second signal line formed on the insulating substrate and insulated from and intersecting the first signal line, the second signal line having a curved portion and a portion extending in a second direction; A first pixel electrode formed for each pixel defined by the crossing of the first signal line and the second signal line; A second pixel electrode formed for each pixel and separated from the first pixel electrode and capacitively coupled to the first pixel electrode; A thin film transistor connected to the first signal line and the second signal line and connected to any one of the first pixel electrode and the second pixel electrode. Including, The bent portion of the second signal line includes two straight portions, one of the two straight portions is a first straight portion that is substantially 135 degrees with respect to the first signal line, and the other is connected to the first signal line. A second straight portion that is substantially 45 degrees relative to, The first pixel electrode and the second pixel electrode are bent in the same manner as the second signal line, The second pixel electrode is divided into two, each having a pair of boundary lines parallel to the first straight line portion and the second straight line portion, and positioned above and below the first pixel electrode, The first pixel electrode includes a pair of boundary lines parallel to the first straight portion and a pair of boundary lines parallel to the second straight portion. delete In claim 1, The thin film transistor is connected to the first pixel electrode, And a coupling electrode connected to the first pixel electrode and overlapping the second pixel electrode in an insulated state. In claim 1, The thin film transistor is connected to the second pixel electrode, And a coupling electrode connected to the second pixel electrode and overlapping the first pixel electrode in an insulated state. The method of claim 3 or 4, The coupling electrode may include a portion that is substantially 135 degrees with respect to the first signal line and a portion that is substantially 45 degrees with respect to the first signal line. The method of claim 3 or 4, The thin film transistor array panel of claim 1, further comprising a storage electrode line formed in parallel with the first signal line, and a storage electrode connected to the storage electrode line and at least partially overlapping the coupling electrode. First insulating substrate, A first signal line formed on the first insulating substrate, A second signal line formed on the first insulating substrate and insulated from and intersecting the first signal line and having a refractive portion; A first pixel electrode formed for each pixel defined by the crossing of the first signal line and the second signal line; A second pixel electrode formed for each pixel and separated from the first pixel electrode and capacitively coupled to the first pixel electrode; A thin film transistor connected to the first signal line and the second signal line and connected to any one of the first pixel electrode and the second pixel electrode; A second insulating substrate facing the first insulating substrate, A common electrode formed on the second insulating substrate, Domain dividing means formed on said second insulating substrate, Liquid crystal layer injected between the first insulating substrate and the second insulating substrate Including, The bent portion of the second signal line includes two straight portions, one of the two straight portions is a first straight portion that is substantially 135 degrees with respect to the first signal line, and the other is connected to the first signal line. A second straight portion that is substantially 45 degrees relative to, The first pixel electrode and the second pixel electrode are bent in the same manner as the second signal line, The first pixel electrode and the second pixel electrode are divided into a plurality of domains by the domain dividing means, and two long sides of the domain are substantially parallel with the refraction portion of the adjacent second signal line, and the second pixel electrode is It is divided into two and has a pair of boundary lines parallel to the said 1st linear part and the said 2nd linear part, respectively, and is arrange | positioned adjacent to the said 1st signal line, The said 2nd pixel electrode makes the said 1st pixel electrode And a plurality of boundary lines parallel to the first straight portion and a pair of boundary lines parallel to the second straight portion. 8. The method of claim 7, The liquid crystal contained in the liquid crystal layer has negative dielectric anisotropy and the liquid crystal has a long axis oriented perpendicular to the first and second substrates. 8. The method of claim 7, And the domain dividing means is a cutout portion of the common electrode.

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