KR20050112630A - Multi-domain liquid crystal display - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-domain liquid crystal display device, and to a liquid crystal display device having a structure in which the asymmetry of diagonal direction visibility is eliminated in low and high gray areas in a vertically aligned (VA) mode liquid crystal display device. .

In the multi-domain liquid crystal display, the pixels of the first type pixel and the second type pixel, which are symmetrical structures, are repeatedly arranged to have symmetry of visibility with respect to left and right diagonals.

Description

Multi Domain Liquid Crystal Display {MULTI-DOMAIN LIQUID CRYSTAL DISPLAY}

The present invention relates to a four-division multi-domain liquid crystal display.

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, through which the light transmittance is controlled to represent the image.

However, it is an important disadvantage that the liquid crystal display device has a narrow viewing angle. To overcome these shortcomings, various measures have been developed to widen the viewing angle. Among them, the most effective method is to use a VA mode in which the liquid crystal molecules are vertically aligned with respect to the upper and lower substrates, and to form a constant incision pattern or protrusion on the pixel electrode and the common electrode as the opposite electrode.

Such a multi-domain liquid crystal display has a contrast ratio reference viewing angle based on a contrast ratio of 1:10 and a gray scale inversion reference viewing angle defined as a limit angle of luminance inversion between gray scales, which are excellent in all directions of 80 ° or more. However, there is a problem in that the gamma curve on the front side and the gamma curve on the side do not coincide with each other, resulting in inferior visibility in the left and right sides compared to the liquid crystal display of the twisted nematic (TN) mode. 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.

Recently, as the liquid crystal display device is used for multimedia, the symmetry of visibility of low gray and high gray areas in the front and left and right diagonals is becoming more and more important as picture viewing and video viewing are increasing.

SUMMARY The present invention has been made in an effort to provide a multi-domain liquid crystal display device having improved symmetry of visibility with respect to left and right diagonals in a vertically aligned (VA) mode liquid crystal display device.

In order to solve this problem, in the present invention, a pixel consisting of a first type pixel and a second type pixel, which are symmetrical structures, is repeatedly formed in a four-division multi-domain liquid crystal display.

Specifically, a first signal line, a second signal line that is insulated from and crosses the first signal line, and is formed for each pixel defined by the intersection of the first signal line and the second signal line, and includes first, second, third, and the like. In a first substrate having a pixel electrode including a fourth pixel electrode and a thin film transistor, three terminals of the thin film transistor are connected to the first signal line, the second signal line, and the first pixel electrode, and are connected to the first pixel electrode. A first type pixel having capacitively coupled second, third and fourth pixel electrodes, and three terminals of the thin film transistor connected to the first signal line, the second signal line, and the fourth pixel electrode; A second type pixel having first, second, and third pixel electrodes coupled capacitively to a fourth pixel electrode is disposed on the first substrate, and the second type is disposed on the top, bottom, left, and right sides of the first type pixel. Pixels are placed A first substrate on which the first type pixel is disposed, a second substrate on which a common electrode facing the pixel electrode is formed, and between the first substrate and the second substrate; The present invention relates to a multi-domain liquid crystal display device including a liquid crystal layer formed on the liquid crystal layer, wherein the liquid crystal layer includes liquid crystal molecules having a long axis perpendicular to the first and second substrates.

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. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

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.

Now, a four-division multi-domain liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, the four-division multi-domain liquid crystal display is formed by repeatedly forming the first type pixel shown in FIG. 1 and the second type pixel shown in FIG. 5 as shown in FIG. 6 to remove asymmetrical visibility in left and right diagonals. It consists of a structure.

First, the first type pixel illustrated in FIG. 1 will be described.

1 is a layout view of a four-division multi-domain liquid crystal display device as a first type pixel of an embodiment of the present invention, FIG. 2 is a layout view of a common electrode display panel of the four-division multi-domain liquid crystal display device used in the present invention, and FIG. 1 is a cross-sectional view of the 4-division multi-domain liquid crystal display of FIG. 1 taken along line III-III ', and FIG. 4 is a cross-sectional view of the 4-division multi-domain liquid crystal display of FIG. 1 taken along line IV-IV'. .

The first type pixel of the present invention is injected between the lower panel 100 and the upper panel 200 facing the lower panel 100 and the lower panel 100 and the upper panel 200 to be oriented perpendicular to the display panels 100 and 200. It consists of a liquid crystal layer 3 containing liquid crystal molecules present. In this case, alignment layers 11 and 21 are formed on each of the display panels 100 and 200, and the alignment layers 11 and 21 perpendicular to the liquid crystal molecules 310 of the liquid crystal layer 3 with respect to the display panels 100 and 200. It is preferred that it is a vertical alignment mode that allows it to be oriented in.

First, the configuration of the lower panel is as follows.

First, second, third and fourth pixel electrodes made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) on the lower insulating substrate 110 made of a transparent insulating material such as glass ( 190a, 190b, 190c, 190d and coupling electrode 176 are formed. The first pixel electrode 190a is directly connected to the thin film transistor TFT to receive an image signal voltage. The second, third, and fourth pixel electrodes 190b, 190c, and 190d are connected to the first pixel electrode 190a. ) And overlaps the coupling electrode 176 extending from the drain electrode 175. The thin film transistor TFT is connected to the gate line 121 that transmits the scan signal and the data line 171 that transmits the image signal, respectively, to turn on the image signal applied to the first pixel electrode 190a according to the scan signal. on) off. In this case, the pixel voltage transferred to the first pixel electrode 190a is transmitted to the coupling electrode 176, and the coupling electrode 176 overlaps the second, third, and fourth pixel electrodes 190b, 190c, and 190d. The change value of the pixel voltage of the first pixel electrode 190a coupled capacitively and initially transmitted is transferred to the second and third pixel electrodes 190b, 190c, and 190d, which will be described in detail later. In this case, the first to fourth pixel electrodes 190a, 190b, 190c, and 190d are separated through the cutout. In addition, although a lower polarizer (not shown) is attached to a lower surface of the insulating substrate 110, the first to fourth pixel electrodes 190a, 190b, 190c, and 190d may be formed of a transparent material in the case of a reflective liquid crystal display. In this case, the lower polarizer is also unnecessary.

Next, the configuration of the upper panel will be described.

Here, the lower surface of the upper insulating substrate 210 made of a transparent insulating material such as glass has an opening in the pixel region, and a black matrix 220 and a color filter of red, green, and blue to prevent light leaking between the pixel regions. 230 and a common electrode 270 formed of a transparent conductive material such as ITO or IZO. The cutout 271 is formed in the common electrode 270, which is illustrated in FIG. 2. The cutout 271 is a domain regulating means for forming the fringe field in the pixel region to divide and align the liquid crystal molecules, and the fringe field formed at the boundary between the first to fourth pixel electrodes 190a, 190b, 190c, and 190d is also a liquid crystal. Domain regulatory means for splitting orientation of molecules. In this case, although the cutouts of the common electrode 270 and the first to fourth pixel electrodes 190a, 190b, 190c, and 190d are used to form a fringe field as domain regulating means, the liquid crystal is induced by inclining the alignment force of the alignment layer. It is also possible to use protrusions for splitting the molecules. The black matrix 220 may be disposed in the shape of a branch not only in the periphery of the pixel region but also in the overlapping portion of the cutout 271 of the common electrode 270, which is a light leakage generated by the cutout 271. This is to prevent.

Next, the first type pixel of the present invention, which is a lower display panel, will be described in more detail with reference to FIGS. 1, 3, and 4.

A plurality of gate lines 121 may be formed on the lower insulating substrate 110 to transfer gate signals. The gate line 121 mainly extends in the horizontal direction, and a part of each gate line 121 forms a plurality of gate electrodes 124. One end portion of the gate line 121 may be widely extended to form a contact portion for connection with an external gate driving circuit. In the case where the contact portion does not have a contact portion, the thin film transistor may be disposed on the substrate 110. An end portion of the gate line 121 is directly connected to an output terminal of the gate driving circuit which is directly formed of the same layer.

In addition, the sustain electrode lines 131a and 131b and the storage electrodes 133a and 133b are formed on the insulating substrate 110. The storage electrode lines 131a and 131b extend in the horizontal direction at the upper and lower edges of the pixel area. The storage electrodes 133a and 133b extend in a direction of 135 degrees with respect to the storage electrode lines 131a and 131b at both edges of the pixel region, and are extended by a predetermined length by bending 90 degrees twice, and the two storage electrode lines 131a and 131b. Are connected to each other, and overlap the first to fourth pixel electrodes 190a, 190b, 190c, and 190d or the coupling electrode 176 to form a storage capacitor.

The gate line 121 and the storage electrode lines 131a and 131b are made of metal such as Al, Al alloy, Ag, Ag alloy, Cr, Ti, Ta, Mo, or the like. Although the gate line 121 of the present embodiment is illustrated as a single layer, it may be composed of a double layer including a metal layer such as Cr, Mo, Ti, Ta, etc. having excellent physical and chemical properties, and an Al-based or Ag-based metal layer having a low specific resistance. .

Side surfaces of the gate line 121 and the storage electrode lines 131a and 131b are inclined, and the inclination angle with respect to the horizontal plane is preferably 30 to 80 degrees.

A gate insulating layer 140 made of silicon nitride (SiNx) or the like is formed on the gate line 121.

A plurality of linear semiconductors 151 made of hydrogenated amorphous silicon (a-Si) or the like are formed on the gate insulating layer 140 of the gate electrode 124. The semiconductor layer 151 includes a channel portion that forms a channel of the thin film transistor TFT, and the semiconductor 151 extends linearly along the data line 171 formed later, and the data line 171 and the gate line. In the position where the 121 and the storage electrode lines (not shown) intersect, they have a wide width and extend in a larger area than the portions where the 171 and 121 cross.

On the semiconductor layer 151, a linear ohmic contact 161 and an island-type ohmic contact 161 made of a material such as n + hydrogenated amorphous silicon doped with silicide or n-type impurities at a high concentration are formed. Formed. The ohmic contact 161 includes a source portion ohmic contact 163 positioned at the center of the gate electrode 124, and the island-type ohmic contact 165 has a source portion resistive around the gate electrode 124. The contact members 163 face each other.

The data line 171 and the drain electrode 175 are formed on the ohmic contacts 161 and 165 and the gate insulating layer 140. The data line 171 extends long and crosses the gate line 121, and has a source electrode 173 connected to the data line 171 and extending to an upper portion of the source ohmic contact 163. The drain electrode 175 is separated from the source electrode 173 and positioned above the drain portion ohmic contact 165 opposite to the source electrode 173 with respect to the gate electrode 124. The drain electrode 175 is connected to a coupling electrode 176 that overlaps the second, third, and fourth pixel electrodes 190b, 190c, and 190d to form a coupling capacitor. One end portion 179 of the data line 171 is a contact portion for connecting with an external circuit, and its width is extended.

Here, the data line 171 has a portion that is repeatedly bent twice and extends vertically with a length of the pixel. At this time, the bent portion of the data line 171 is composed of four straight portions, two of the four straight portions form 45 degrees with respect to the gate line 121, the other two are the gate line 121 ) Is -45 degrees relative to). The source electrode 173 is connected to a vertically extending portion of the data line 171, and the portion crosses the gate line 121. In this case, the data line 171 may be bent only once per unit pixel or may be bent three or more times.

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 has a curved band shape.

The coupling electrode 176 has a curved shape along the bent shape of the pixel, and covers the horizontal branch 177 extending in the horizontal or vertical direction at the curved boundary of the pixel. The horizontal branch 177 has a function of blocking light leaking at the boundary of the region divided into small regions.

A-Si: C: O, a-Si: O: formed by plasma enhanced chemical vapor deposition (PECVD) on the data line 171, the drain electrode 175, and the exposed semiconductor layer 154. A passivation layer 180 made of a low dielectric constant insulating material such as F or a silicon nitride or an organic insulating material, which is an inorganic material, is formed. In this case, the passivation layer 180 may have a different thickness according to the position of the coupling electrode 176, which is formed after the second, third and fourth pixel electrodes 190b, 190c, and 190d and the coupling electrode 176. This is to differently adjust the pixel voltage transferred to the second, third and fourth pixel electrodes 190b, 190c, and 190d by differently adjusting the coupling capacitance formed therebetween.

In the passivation layer 180, a contact hole 185 exposing the drain electrode 175 is formed. In addition, the passivation layer 180 may have a contact hole that exposes an end portion (not shown) of the gate line 121 and the data line 171 together with the gate insulating layer 140. And a contact portion for connecting the data line with the driving circuit. In addition, the passivation layer 180 has contact holes 184 exposing the storage electrode lines 131a and 131b.

In this case, the sidewalls of the contact holes 185 and 182 may have a gentle inclination of about 30 to 80 degrees with respect to the surface of the substrate 110, and may be formed in various shapes in an angle or planar shape in plan view. It does not exceed 2 mm x 60 micrometers, and it is preferable that it is 0.5 mm x 15 micrometers or more.

First and fourth pixel electrodes 190a and 190d having incomplete parallelogram shapes are formed on the passivation layer 180, respectively, and second and third pixel electrodes 190b and 190c having parallelograms which are exchanged with each other. In this case, the first pixel electrode 190a is connected to the drain electrode 175 through the contact hole 185, and the second, third and fourth pixel electrodes 190b, 190c, and 190d are connected to the drain electrode 175. And overlap with the coupling electrode 176 connected to the electrode. Accordingly, the second, third and fourth pixel electrodes 190b, 190c, and 190d are electromagnetically coupled (capacitively coupled) to the first pixel electrode 190a.

The first to fourth pixel electrodes 190a, 190b, 190c, and 190d are separated from each other. In the present exemplary embodiment, the first to fourth pixel electrodes 190a, 190b, 190c, and 190d have a parallelogram shape, but may be bent along the shape of the pixel.

On the other hand, a contact auxiliary member may be formed on the passivation layer 180 respectively connected to an end portion of the data line or the gate line through a contact hole. A connection member 84 is formed on the passivation layer 180 to connect the storage electrode lines 131a and 131b disposed in the pixel area adjacent to each other through the contact hole 184.

The first to fourth pixel electrodes 190a, 190b, 190c, and 190d may be formed of indium tin oxide (ITO) or indium zinc oxide (IZO).

Now, the opposing display panel will be described with reference to FIGS. 2 to 4.

Facing the lower insulating substrate 110, a black matrix 220 is formed on the lower surface of the upper substrate 210 made of a transparent material such as glass to prevent light leakage. Each pixel is red, green, and blue. The color filters 230 are sequentially formed, and the overcoat layer 250 made of silicon nitride or an organic material is formed on the color filters 230. The overcoat layer 250 is formed of a transparent conductive material such as ITO or IZO, and a common electrode 270 having a cutout 271 is formed.

At this time, the cutout 271 forms a fringe field with the boundaries of the first to fourth pixel electrodes 190a, 190b, 190c, and 190d to act as domain regulating means for dividing the liquid crystal molecules. It is preferable that it is between 9 micrometers and 12 micrometers. In the case of forming the organic protrusions instead of the cutouts 271 by domain regulating means, it is preferable to set the width between 5 μm and 10 μm.

Also, the black matrix 220 includes a linear portion corresponding to the curved portion of the data line 171, a vertically extending portion of the data line 171, and a portion corresponding to the thin film transistor portion.

Meanwhile, domain restricting means such as the cutout 271 may be provided in the pixel electrodes 190a, 190b, 190c, and 190d, and the protrusion may also be disposed on the pixel electrodes 190a, 190b, 190c, and 190d. .

The red, green, and blue color filters 230 are formed lengthwise along the pixel columns partitioned by the black matrix 220, and are periodically bent along the shape of the pixels.

The cutout 271 is also bent to form a bent pixel. In addition, both ends of the cutout 271 is bent once more so that one end has a branch 272 parallel to the gate line 121, and the cutout 271 divides the pixel from side to side in the center of the pixel, It may have branches 274 and 274 ′ that divide the portion up and down and overlap the branches 177 of the coupling electrode 176. At this time, the plurality of branches (274, 274 ') can be cut in the same area with each other, but may be different as in this embodiment. The area of the branch 274 positioned between the first pixel electrode 190a and the second pixel electrode 190b and the branch 274 'positioned between the third pixel electrode 190c and the fourth pixel electrode 190d. By differently configuring the first and fourth pixel electrodes 190a, 190b, 190c, 190d and the common electrode 270, the areas overlapping each other may be adjusted differently.

In addition, the cutout 271 has a narrowed portion, and the portion of the common electrode 270 that protrudes into the narrowed portion is called the notch 273. The notch 273 may have a triangular or square or trapezoidal or semi-circular shape, and the liquid crystal molecules arranged at the boundary of the domain may be stably and regularly arranged through the notch 273, thereby causing stains or afterimages at the domain boundary. This can be prevented from occurring.

When the liquid crystal layer is formed by combining the thin film transistor array panel 100 and the common electrode panel 200 having the above structure and injecting liquid crystal therebetween, the first type of the liquid crystal display device as shown in FIGS. 3 and 4. Pixels are made.

The liquid crystal molecules included in the liquid crystal layer have the directors of the lower substrate 110 and the upper portion in the state in which no electric field is applied between the first to fourth pixel electrodes 190a, 190b, 190c, and 190d and the common electrode 270. It is oriented perpendicular to the substrate 210 and has negative dielectric anisotropy.

3 and 4, in the lower substrate 110 and the upper substrate 210, the first to fourth pixel electrodes 190a, 190b, 190c, and 190d accurately correspond to the color filter 230. The overlaps and the cutouts 271 of the common electrode 270 are aligned to overlap the coupling electrode 176.

In such a liquid crystal display, the liquid crystal molecules of the pixel are divided and oriented into a plurality of domains by the fringe field of the cutout 271. In this case, one pixel includes eight types of domains in which the first to fourth pixel electrodes 190a, 190b, 190c, and 190d are bilaterally divided by the cutouts 271, respectively, so that the alignment directions of the liquid crystals of the liquid crystal are different from each other. Divided.

Although the color filter 230 is disposed on the opposing display panel 200 in the structure of the liquid crystal display device, the color filter 230 may be disposed on the thin film transistor array panel 100. In this case, the lower portion of the gate insulating layer 140 or the passivation layer 180 may be disposed. Can be formed on.

The liquid crystal display is formed by disposing elements such as a polarizer, a backlight, and a compensation plate on both sides of the basic panel. In this case, one polarizer is disposed on each side of the base panel, and the transmission axis thereof is disposed so that one of the two 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 a direction perpendicular to the data line 171, the side direction formed between two neighboring first to fourth pixel electrodes 190a, 10b, 190c, and 190d with the data line 171 therebetween. It corresponds to the direction in which the liquid crystal is inclined by the electric field. Therefore, 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 used. Almost always occurs and the direction becomes the direction which 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.

In addition, the present invention improves the visibility in the diagonal direction asymmetrically to improve the visibility in the left and right diagonal direction. Asymmetry of the visibility in the diagonal direction is a problem that occurs when the shape of the pixel is formed in a band shape (hereinafter, referred to as a "boomerang structure") as in the embodiment of the present invention. That is, when the light is emitted only through the first domain in the 4-divided structure having a boomerang structure, the gamma curve is distorted because the liquid crystal rotates on a plane that is 90 ° to the line of sight when viewed from a diagonal 45 ° upper layer. It doesn't work. However, when viewed from a diagonal 135 ° upward direction, the gamma curve is severely distorted because the liquid crystal rotates on a plane parallel to the line of sight. This result is clearly shown in FIG.

Also, in the liquid crystal display having the structure, an image signal voltage transmitted through the data line 171 is applied to the first to fourth pixel electrodes 190a, 190b, 190c, and 190d through the thin film transistor TFT. Since the first pixel electrode 190a is directly connected to the drain electrode 175, the image signal voltage is applied as it is, and the coupling electrode 176 is applied to the second, third and fourth pixel electrodes 190b, 190c, and 190d. Since the voltage formed by the capacitive coupling with is applied, a voltage having a small absolute value is applied to the voltage applied to the first pixel electrode 190a.

As such, when a plurality of pixel electrodes having different voltages are disposed in one pixel area, each of the pixel electrodes 190a, 190b, 190c, and 190d compensates each other to reduce distortion of the gamma curve. In this case, the sum of the pixel voltages of the first pixel electrode 190a and the third pixel electrode 190c and the sum of the pixel voltages of the second pixel electrode 190b and the fourth pixel electrode 190d are preferably the same. The difference with respect to the sum of the pixel voltages is preferably within 80%. For this purpose, the coupling electrode 176 overlapping the first to fourth pixel electrodes 190a, 190b, 190c, and 190d may have different widths (a, b, and c) depending on the position, and the width thereof is 3- Various adjustments can be made in the range of 15 μm.

In the case of the first type pixel used in the present exemplary embodiment, as shown in FIG. 1, the widths a, b, and c of the coupling electrode 176 overlap the second pixel electrode 190b. ) Has the widest width c, the width a of the coupling electrode 176 overlapping the fourth pixel electrode 190d is next widest, and the coupling electrode overlapping the third pixel electrode 190c. The width b of 176 is formed to be the narrowest.

Meanwhile, the thickness of the passivation layer 190 may be formed differently according to the position in order to change the pixel voltage transmitted to the first to fourth pixel electrodes 190a, 190b, 190c, and 190d.

So far, the first type pixel used in the liquid crystal display device has been described in detail. Hereinafter, a second type pixel used in the liquid crystal display will be described. The second type pixel is shown in FIG.

The cross section of the second type pixel shown in FIG. 5 has the same layered structure as shown in FIGS. 3 and 4. That is, the plurality of linear semiconductors including the plurality of gate lines 121 including the plurality of gate electrodes 124 is formed on the substrate 110, and the gate insulating layer 140 and the plurality of protrusions 154 thereon. 151, a plurality of linear ohmic contact members 161 each including a plurality of protrusions 163, and a plurality of island type ohmic contact members 165 are sequentially formed. A plurality of data lines 171 including a plurality of source electrodes 173, a plurality of drain electrodes 175, and a plurality of coupling electrodes 176 are formed on the ohmic contacts 161 and 165 and the gate insulating layer 140. The protective film 180 is formed thereon. A plurality of contact holes 182 are formed in the passivation layer 180 and / or the gate insulating layer 140.

The first to fourth pixel electrodes 190a, 190b, 190c, and 190d are separated from each other on the passivation layer 180, and have a parallelogram shape. In this case, unlike the first type pixel, in the second type pixel, the fourth pixel electrode 190d is connected to the coupling electrode 176 connected to the drain electrode 175 through the contact hole 185. The first to third pixel electrodes 190a, 190b, and 190c overlap the coupling electrode 176 and are capacitively coupled to the fourth pixel electrode 190d.

The sum of the pixel voltages of the first pixel electrode 190a and the third pixel electrode 190c and the sum of the pixel voltages of the second pixel electrode 190b and the fourth pixel electrode 190d are preferably the same. The difference in sum is preferably within 80%.

To this end, the coupling electrodes 176 overlapping the second to fourth pixel electrodes 190b, 190c, and 190d have different widths a, b, and c for each part. In this case, the widths a, b, and c of the coupling electrode 176 have the largest width c of the coupling electrode 176 overlapping with the third pixel electrode 190c, and the first pixel electrode 190a The width a of the overlapping coupling electrode 176 is next widest, and the width b of the coupling electrode 176 overlapping the second pixel electrode 190b is formed to be the narrowest.

Therefore, when the same image voltage is applied to the first type pixel and the second type pixel, the voltage applied to the first to fourth pixel electrodes 190a, 190b, 190c, and 190d is applied to the first type pixel and the second type pixel. Are different. In this case, voltages applied to the first pixel electrode 190a of the first type pixel and the fourth pixel electrode 190d of the second type pixel are the same, and the second pixel electrode 190b and the second pixel of the first type pixel are the same. Voltages applied to the third pixel electrode 190c of the type pixel are the same, and voltages applied to the third pixel electrode 190c of the first type pixel and the second pixel electrode 190b of the second type pixel are equal to each other. In addition, voltages applied to the fourth pixel electrode 190d of the first type pixel and the first pixel electrode 190a of the second type pixel are the same. That is, in the first type pixel, the voltage arrangement appearing from the first pixel electrode 190a to the fourth pixel electrode 190d moves from the fourth pixel electrode 190d to the first pixel electrode 190a in the second type pixel. appear.

The first type pixel and the second type pixel are arranged as shown in FIG. 6 to form a liquid crystal display device. That is, dots consisting of red pixels, green pixels, and blue pixels, which are the second type pixels, are provided on the top, bottom, left, and right sides of a dot composed of red (R) pixels, green (G) elements, and blue (B) pixels, which are the first type pixels. Are arranged, and the first type pixels are arranged on the images left and right of the dot formed of the second type pixels.

In other words, the pixels are arranged so that the dots made of the first type pixels and the dots made of the second type pixels alternately appear in the horizontal direction and the vertical direction.

In this way, the dot composed of the first type pixel and the dot composed of the second type pixel are compensated with each other, so that the visibility in the left and right is the same. For example, a liquid crystal display device in which an image voltage that is low enough to operate only a liquid crystal placed on a first pixel electrode 190a of a first type pixel and a fourth pixel electrode 190d of a second type pixel may operate. If the gamma curve of the second type pixel is distorted, but the gamma curve of the first type pixel is not distorted, as shown in FIG. 7, the image according to the average gamma curve of the two gamma curves is shown. This is admitted. Therefore, the visibility can be improved compared to the case of only the second type pixel. On the contrary, when viewed from a diagonal angle of 135 degrees upward, the gamma curve of the first type pixel is distorted, but the gamma curve of the second type pixel is not distorted. Therefore, even when looking from the diagonal 135 degree upward direction, the image which is almost the same as when looking from the diagonal 45 degree upward direction is recognized. Therefore, the left and right visibility becomes the same.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

As described above, in the four-division multi-domain liquid crystal display device, by repeatedly arranging pixels of the first type pixel and the second type pixel, visibility of the left and right diagonals is symmetrical.

1 is a layout view of a four-division multidomain liquid crystal display device as a first type pixel of an embodiment of the present invention;

2 is a layout view of a common electrode display panel of a four-division multi-domain liquid crystal display device used in the present invention.

FIG. 3 is a cross-sectional view of the 4-divided multi-domain liquid crystal display of FIG. 1 taken along line III-III ',

4 is a cross-sectional view of the 4-divided multi-domain liquid crystal display of FIG. 1 taken along the line IV-IV '.

5 is a layout view of a four-division multi-domain liquid crystal display device as the second type pixel of the embodiment of the present invention,

FIG. 6 is a diagram illustrating a pixel array of a four-division multi-domain liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 7 is a graph illustrating gamma characteristics in a diagonal direction according to an exemplary embodiment of the present invention, and shows a gamma characteristic of a diagonal of 45 degrees and a diagonal of 135 degrees in accordance with a conventional four-division multidomain liquid crystal display.

Description of the main parts of the drawing

3: liquid crystal layer 310: liquid crystal molecules

11: alignment film 21: alignment film

100: lower display panel 110: lower insulating substrate

121: gate line 124: gate electrode

131a and 131b: sustain electrode line 133a and 133b: sustain electrode

140: gate insulating film 151: semiconductor layer

161, 165: ohmic contact layer

171: data line 173: source electrode

175: drain electrode 176: coupling electrode

177: basin

190a, 190b, 190c, 190d: first, second, third, and fourth pixel electrodes

200: upper display panel 210: upper insulating substrate

22: black matrix 230: color filter

270: common electrode 271: incision

Claims (12)

First signal line, A second signal line insulated from and intersecting the first signal line to define a pixel region; A first pixel electrode and a second pixel electrode capacitively coupled to each other, And a thin film transistor having a gate electrode connected to the first signal line, a source electrode connected to the second signal line, and a drain electrode connected to any one of the first pixel electrode and the second pixel electrode. , The first and second pixel electrodes are separated, and the first pixel electrode and the second pixel electrode are distinguished according to positions in the pixel area. A first type pixel having a drain electrode of the thin film transistor connected to a first pixel electrode, and a second type pixel having a drain electrode of the thin film transistor connected to a second pixel electrode, The thin film transistor array panel of which the first type pixel and the second type pixel alternately appear along the column direction of the pixel region. In claim 1, When three consecutive pixel areas are called one dot, The dot is divided into a first type dot composed only of a first type pixel and a second type dot composed only of a second type pixel, A thin film transistor array panel in which first type dots and second type dots alternately appear along a row direction of the pixel region. In claim 1, And a coupling electrode overlapping the first pixel electrode and the second pixel electrode to capacitively couple the first pixel electrode and the second pixel electrode. In claim 3, The coupling electrode may have a width overlapping the first pixel electrode and a width overlapping the second pixel electrode. In claim 4, The width of the coupling electrode overlapping the first pixel electrode in the first type pixel is the same as the width of the coupling electrode overlapping the second pixel electrode in the second type pixel, and overlaps with the second pixel electrode in the first type pixel. And a width of the coupling electrode overlapping the first pixel electrode in the second type pixel. In claim 1, The thin film transistor array panel is capacitively coupled to the first pixel electrode and the second pixel electrode, and is disposed between the first pixel electrode and the second pixel electrode in the pixel area. A thin film transistor array panel further comprising an electrode. In claim 6, The thin film transistor further includes a coupling electrode overlapping the first to fourth pixel electrodes so that the first pixel electrode, the second pixel electrode, the third pixel electrode, and the fourth pixel electrode are capacitively coupled to each other. Display panel. In claim 7, The first type pixel and the second type pixel are positioned in the pixel region in order of a first pixel electrode, a third pixel electrode, a fourth pixel electrode, and a second pixel electrode. The width of the coupling electrode overlapping the first pixel electrode in the first type pixel is the same as the width of the coupling electrode overlapping the second pixel electrode in the second type pixel, and overlaps with the third pixel electrode in the first type pixel. The width of the coupling electrode is equal to the width of the coupling electrode overlapping the fourth pixel electrode in the second type pixel, and the width of the coupling electrode overlapping the fourth pixel electrode in the first type pixel and the width of the second type pixel. The width of the coupling electrode overlapping the third pixel electrode is the same, the width of the coupling electrode overlapping the second pixel electrode in the first type pixel and the width of the coupling electrode overlapping the first pixel electrode in the second type pixel Like thin film transistor display panel. In claim 8, The sum of the voltages applied to the first pixel electrode and the fourth pixel electrode of the first type pixel is equal to the sum of the voltages applied to the second pixel electrode and the third pixel electrode, And a sum of voltages applied to the first pixel electrode and the fourth pixel electrode of the second type pixel and a sum of the voltages applied to the second pixel electrode and the third pixel electrode. A first signal line, a second signal line insulated from and intersecting the first signal line to define a pixel region, a first pixel electrode and a second pixel electrode capacitively coupled to each other, a gate electrode connected to the first signal line, A first substrate having a thin film transistor having a source electrode connected to the second signal line, a drain electrode connected to any one of the first pixel electrode and the second pixel electrode, A second substrate having a common electrode facing the first pixel electrode and the second pixel electrode. A liquid crystal molecule formed between the first substrate and the second substrate, the long axis of which is perpendicular to the first and second substrates, The first and second pixel electrodes are separated, and the first pixel electrode and the second pixel electrode are distinguished according to positions in the pixel area. A first type pixel having a drain electrode of the thin film transistor connected to a first pixel electrode, and a second type pixel having a drain electrode of the thin film transistor connected to a second pixel electrode, The multi-domain liquid crystal display of which the first type pixel and the second type pixel alternately appear along the column direction of the pixel area. In claim 10, When three consecutive pixel areas are called one dot, The dot is divided into a first type dot composed only of a first type pixel and a second type dot composed only of a second type pixel, And a first type dot and a second type dot alternately appear along the row direction of the pixel region. In claim 11, The dot has three pixel areas of red, green, and blue in order, and a red pixel area of the second type dot is located on the right side of the blue pixel area of the first type dot, and a red pixel area of the first type dot. The blue pixel region of the second type dot is located at the left side of the pixel, and the red, green, blue pixel area of the second type dot is located at the top and bottom of the red, green, and blue pixel areas of the first type dot. A multi-domain liquid crystal display device in which red, green, and blue pixel areas of a first type dot are positioned above and below red, green, and blue pixel areas of a type dot.