KR20060012761A - Thin film transistor array panel and liquid crystal display including the same - Google Patents

Abstract

A gate line formed on an insulating substrate, a data line insulated from and intersecting the gate line, a first pixel electrode, a gate line, a data line, and a first pixel electrode formed in each pixel region defined by the intersection of the gate line and the data line A liquid crystal display device including a thin film transistor having three terminals connected to each other and a second pixel electrode formed in each pixel area and capacitively coupled to the first pixel electrode is provided. In this case, the pixel includes red, green, and blue pixels, and the ratio of the luminance to the red, green, and blue gray scales in the front gamma curve and the ratio of the luminance to the red, green, and blue gray scales of the side gamma curves are the same. The first pixel electrode and the second pixel electrode have different area ratios or voltage ratios in the red, blue, and green pixels. In this way, the side visibility can be improved and the liquid crystal display device which can maximize transmittance | permeability can be obtained.

LCD, vertical alignment, coupling electrode, coupling capacitance, voltage ratio, area ratio

Description

Thin film transistor array panel and liquid crystal display including the same {THIN FILM TRANSISTOR ARRAY PANEL AND LIQUID CRYSTAL DISPLAY}

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

2 is a layout view of an opposing display panel for a liquid crystal display according to an exemplary embodiment of the present invention;

3 is a layout view of a green (G) pixel of a liquid crystal display according to an exemplary embodiment of the present invention including the two display panels of FIGS. 1 and 2.

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

5 is a circuit diagram of one pixel in a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 6 is a gamma curve representing a transmittance according to a gray voltage applied to a pixel.

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

FIG. 8 is a cross-sectional view of the thin film transistor array panel of FIG. 7 taken along the line VIII-VIII ′,                 

9 is a layout view illustrating a structure of a thin film transistor array panel according to another exemplary embodiment of the present invention.

FIG. 10 is a cross-sectional view of the liquid crystal display including the thin film transistor array panel of FIG. 9 taken along the line X-X 'of FIG. 9;

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

FIG. 12 is a cross-sectional view taken along the line XII-XII ′ in FIG. 11.

121 gate lines, 124 gate electrodes,

133a, 133b, 133c sustain electrode, 176 bond electrode,

171 data lines, 173 source electrodes,

175 drain electrodes, 190 pixel electrodes,

191, 192, 193 incisions, 151, 154 amorphous silicon layer,

270 reference electrode, 271, 272, 273 incision

The present invention relates to a liquid crystal display device and a thin film transistor array panel used therein.

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

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

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

The protrusions are formed by forming protrusions on the pixel electrode and the common electrode formed on the upper and lower display panels, respectively, to adjust the lying direction of the liquid crystal molecules using an electric field distorted by the protrusions.

In another method, an incision pattern is formed on the pixel electrode formed on the lower panel, and protrusions are formed on the common electrode formed on the upper panel, so that the liquid crystal lies down using a fringe field formed by the incision pattern and the protrusion. There is a way to form a domain by controlling.

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, the gamma curve of the front side and the gamma curve of the side do not coincide with each other, resulting in inferior visibility in the left and right sides. 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.

The technical problem to be achieved by the present invention is to implement a thin film transistor array panel having excellent visibility and a liquid crystal display device including the same.

In order to solve this problem, the present invention divides the pixel electrode into two, and different potentials are applied to the two sub pixel electrodes, and the voltage ratio or the area ratio between the two sub pixels is different in the red, green, and blue pixels.

In more detail, in the thin film transistor array panel and the liquid crystal display including the same, a plurality of first signal lines and a plurality of second signal lines that are insulated from and cross the first signal lines are formed on the insulating substrate, and the first signal line and the second signal line are formed. The plurality of pixels defined by the crossing are formed with a thin film transistor having three terminals connected to the first pixel electrode, the first signal line, and the second signal line, respectively, and a second pixel electrode capacitively coupled to the first pixel electrode. have. In this case, the pixel includes red, green, and blue pixels, and the ratio of the luminance to the gray, red, green, and blue of the side gamma curve and the ratio of the luminance of the red, green, and blue of the side gamma curve are the same. The first pixel electrode and the second pixel electrode have different area ratios in the red, blue, and green pixels.

The area ratio of the second pixel electrode to the first pixel electrode is preferably at least smaller than the red and blue pixels in the green pixel, and preferably decreases in the order of the blue, red, and green pixels.

The coupling capacitance may be different from each other in the red, green, and blue pixels, and may further include a coupling electrode connected to the first pixel electrode and overlapping the second pixel electrode in an insulated state.

At least one of the first pixel electrode and the second pixel electrode preferably has domain dividing means, and the area of the coupling electrode polymerized with the second pixel electrode is preferably reduced in the order of green, red, and blue pixels.

In this case, the first pixel electrode and the second pixel electrode are red, green, and blue in the front gamma curve so that the ratio of the luminance to the red, green, and blue gray levels of the side gamma curve is the same. The blue and green pixels may have different voltage ratios.

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.

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

1 is a layout view of a thin film transistor substrate for a liquid crystal display according to an embodiment of the present invention, FIG. 2 is a layout view of a color filter substrate for a liquid crystal display according to an embodiment of the present invention, and FIG. FIG. 4 is a layout view of a green (G) pixel in a liquid crystal display according to an exemplary embodiment including the two display panels of FIG. 2, and FIG. 4 is a cross-sectional view taken along line IV-IV ′ of FIG. 3.

As shown in FIG. 4, the liquid crystal display is injected between the lower panel 100, the upper panel 200 facing the lower panel, and the lower panel 100 and the upper panel 200 to be perpendicular to the display panels 100 and 200. It consists of a liquid crystal layer 3 comprising liquid crystal molecules 310 which are oriented.

The lower panel 100 includes first and second pixel electrodes 190a formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) on an insulating substrate 110 made of a transparent insulating material such as glass. , 190b) is formed. The first pixel electrode 190a is connected to the thin film transistor to receive an image signal voltage, and the second pixel electrode 190b overlaps the coupling electrode 176 connected to the first pixel electrode 190a to form a first pixel. It is electromagnetically coupled (capacitively coupled) with the pixel electrode 190a.

In this case, an area in which the second pixel electrode 190b overlaps the coupling electrode 176 is different for each of the red, green, and blue pixels.

In addition, the lower polarizing plate 12 is attached to the lower surface of the insulating substrate 110. Here, the first and second pixel electrodes 190a and 190b may not be made of a transparent material in the case of a reflective liquid crystal display device, and in this case, the lower polarizer 12 is also unnecessary.

Next, the configuration of the upper panel is as follows.

It is also made of a black matrix 220 to prevent light leakage on the lower surface of the insulating substrate 210 made of a transparent insulating material such as glass, a color filter 230 of red, green, and blue and a transparent conductive material such as ITO or IZO. The common electrode 270 is formed. Here, the cutouts 271, 272, and 273 are formed in the common electrode 270. The black matrix 220 may be formed not only in the peripheral portion of the pixel region but also in the portion overlapping the cutouts 271, 272, and 273 of the common electrode 270. This is to prevent light leakage caused by the cutouts 271, 272, and 273.

Alignment layers 11 and 21 are formed in the display panels 100 and 200 to align the liquid crystal molecules 310, and the alignment layers 11 and 21 may be in a vertical alignment mode, but may not be.

More specifically, the thin film transistor array panel 100 as the lower panel 100 has the following configuration.

A plurality of gate lines 121 and storage electrode lines 131 extending mainly in the horizontal direction are formed on the lower insulating substrate 110.

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. The gate electrode 124 is formed in the form of a protrusion in the gate line 121, and as shown in the present embodiment, the gate line 121 may have a contact portion for transmitting a gate signal from the outside to the gate line 121. In this case, the end portion 129 of the gate line 121 has a wider width than the other portion, the gate driving circuit may be mounted on the flexible printed circuit board or formed directly on the substrate 10, the gate line ( The end portion of 121 is connected to the output terminal of the gate driving circuit.

Each storage electrode line 131 extends in the horizontal direction together with the gate line 121, and includes a plurality of storage electrodes 133a, 133b, and 133c extending therefrom. Two storage electrodes 133a and 133b of the pair of storage electrodes 133a, 133b, and 133c extend in the vertical direction and are connected to each other by another storage electrode 133c extending in the horizontal direction. In this case, each of the storage electrode lines 131 may be formed of two or more horizontal lines.

The gate line 121 and the storage electrode line 131 are made of metal such as Al, Al alloy, Ag, Ag alloy, copper or copper alloy, Cr, Ti, Ta, Mo, or molybdenum alloy. As shown in FIG. 4, the gate line 121 and the storage electrode line 131 of the present embodiment are formed of a single layer, but have a high physical and chemical properties such as Cr, Mo, Ti, Ta, and the like and an Al series having a small specific resistance or It may be made of a double layer including a metal layer of Ag-based or copper (Cu). In addition, the gate line 121 and the storage electrode line 131 may be made of various metals or conductors.

Side surfaces of the gate line 121 and the storage electrode line 131 are inclined, and the inclination angle with respect to the horizontal plane is 30-80 °.

A gate insulating layer 140 made of silicon nitride (SiNx) or the like is formed on the gate line 121 and the storage electrode line 131.

A plurality of drain electrodes 175, including a plurality of data lines 171, are formed on the gate insulating layer 140. Each data line 171 extends mainly in a vertical direction and has a source electrode 173 extending from the data line 171 by extending a plurality of branches toward each drain electrode 175. The contact unit 179 located at one end of the data line 171 transfers an image signal from the outside to the data line 171.

On the same layer as the data line 171, a plurality of coupling electrodes 176 connected to the drain electrode 175 and a plurality of under-bridge metal pieces 172 positioned on the gate line 121 are provided. Formed.

The coupling electrode 176 is refracted in a V shape and has different lengths for each of the red (R), green (G), and blue (B) pixels. Here, the coupling electrode 176 of the green (G) pixel is the longest, the coupling electrode 176 of the red (R) pixel is next, and the coupling electrode 176 of the blue (B) pixel is the shortest. This is to adjust the coupling capacitance of the sub-pixel electrode 190b formed in the red (R), green (G), and blue (B) pixels differently, and the length of the coupling electrode 176 according to each pixel is the present embodiment. Unlike the example, it can be modified differently.

Similar to the gate line 121, the data line 171, the drain electrode 175, the coupling electrode 176, and the leg metal piece 172 are Al, Al alloy, Ag, Ag alloy, copper or copper alloy, Cr, Ti, and the like. , Made of metals such as Ta, Mo, or molybdenum alloys, and a double layer including a metal layer of Cr, Mo, Ti, Ta, etc. having excellent physicochemical properties, and a metal layer of Al-based or Ag-based or copper (Cu) having a low specific resistance. It may be made of.

Under the data line 171 and the drain electrode 175, a plurality of linear semiconductors 151 extending mainly vertically along the data line 171 are formed. Each linear semiconductor 151 made of amorphous silicon branches to the gate electrode 124, the source electrode 173, and the drain electrode 175 to form a channel 154 of the thin film transistor.

Between the semiconductor 151, the data line 171, and the drain electrode 175, a plurality of linear ohmic contacts 161 and island-like ohmic contacts 165 for reducing contact resistance therebetween, respectively. Is formed. The ohmic contact 161 is made of amorphous silicon doped with a high concentration of silicide or n-type impurities, has a branched ohmic contact 163, and the island-type ohmic contact 165 has a gate electrode 124. Face the resistive contact member 163.

On the data line 171, the drain electrode 175, and the leg metal piece 172, an organic material having excellent planarization characteristics and a photosensitive property on the data line 171 and the drain electrode 175, and plasma enhanced chemical vapor deposition. A protective film 180 made of a low dielectric constant insulating material such as a-Si: C: O, a-Si: O: F, or silicon nitride formed by vapor deposition (PECVD) is formed.

The passivation layer 180 includes a plurality of contact holes 185 and 182 exposing at least a portion of the drain electrode 175 and an end portion 179 of the data line 171, respectively, and the end of the gate line 121. A plurality of contact holes 181, 184, and 183 exposing portions of the portion 129 and the storage electrode line 131 penetrate the gate insulating layer 140 and the passivation layer 180, respectively.

A plurality of contact assistants 81 and 82 and a plurality of storage bridges 84 are formed on the passivation layer 180, as well as a plurality of pixel electrodes 190a and 190b. The pixel electrodes 190a and 190b, the contact assistants 81 and 82, and the connection legs 84 may be formed of a transparent conductor such as indium tin oxide (ITO) or indium zinc oxide (IZO), or a light reflection characteristic such as aluminum (Al). This excellent opaque conductor is made.

The pixel electrodes 190a and 190b are classified into the first pixel electrode 190a and the second pixel electrode 190b, and the first pixel electrode 190a is connected to the drain electrode 175 through the contact hole 185. The second pixel electrode 190b overlaps the coupling electrode 176. Therefore, the second pixel electrode 190b is electromagnetically coupled (capacitively coupled) to the first pixel electrode 190a. At this time, the coupling capacitance of the first pixel electrode 190a and the second pixel electrode 190b becomes smaller in the order of the green (G), red (R), and blue (B) pixels, which is the coupling electrode 176. This is due to the difference in the length of each pixel. By varying the lengths of the coupling electrodes 176, the coupling capacitances of the first pixel electrode 190a and the second pixel electrode 190b are different in the green (G), red (R), and blue (B) pixels. In addition to the method, there are various methods such as varying the width of the coupling electrode or different arrangements. In this case, when the area ratio of the second pixel electrode 190b to the first pixel electrode 190a is 1 in the red (R) pixel, it is smaller than 1 in the green (G) pixel and less than 1 in the blue (B) pixel. It is desirable to be large.

The boundary dividing the first pixel electrode 190a and the second pixel electrode 190b is divided into portions perpendicular to the portions 191 and 193 forming 45 ° with respect to the gate line 121, and forming a 45 ° portion. The length of the two parts 191 and 193 is longer than that of the vertical part. In addition, the two portions 191 and 193 constituting 45 ° are perpendicular to each other.

The second pixel electrode 190b has a cutout 192, and the cutout 192 penetrates from the right side of the second pixel electrode 190b toward the left side, and the inlet is widened.

Each of the first pixel electrode 190a and the second pixel electrode 190b is substantially a line (parallel with the gate line) that bisects the pixel region defined by the intersection of the gate line 121 and the data line 171. Mirror image symmetry.

Further, on the passivation layer 180, a storage wiring connecting leg 84 is formed to connect the two storage electrode lines 131 that are positioned on both sides of the gate line 121. The storage wiring connection bridge 84 is in contact with the storage electrode 133a and the storage electrode line 131 through the contact holes 183 and 184 penetrating through the passivation layer 180 and the gate insulating layer 140. The sustain wiring connection leg 84 overlaps the leg metal piece 172. The storage wiring connection bridge 84 serves to electrically connect the entire storage electrode line 131 on the lower substrate 110. The storage electrode line 131 may be used to repair a defect of the gate line 121 or the data line 171, if necessary, and the metal part 172 of the bridge 121 may emit the gate line 121 when irradiating a laser for such repair. And to maintain the electrical connection of the retaining wire connecting bridge (84).

The contact auxiliary members 81 and 82 are connected to the end portion 129 of the gate line and the end portion 179 of the data line through the contact holes 181 and 182, respectively.

Next, the opposing display panel 200 will be described in detail.

A black matrix 220 is formed on the insulating substrate 210 to prevent light leakage between pixels adjacent to each other with an opening in the pixel. Red, green, and blue color filters 230 are sequentially formed in each pixel, and overlap the black matrix 220 at the edge portion. The common electrode 270 having a plurality of cutouts 271, 272, and 273 is formed on the color filter 230. The common electrode 270 is formed of a transparent conductor such as ITO or indium zinc oxide (IZO).

A pair of cutouts 271, 272, and 273 of the common electrode 270 has a portion 191, 193 formed at 45 ° with respect to the gate line 121 among the boundary of the two pixel electrodes 190a and 190b. It includes an oblique portion parallel to the side and an end portion overlapping the sides of the pixel electrode 190. At this time, the end is classified into a longitudinal end part and a horizontal end part.

When the thin film transistor array panel and the color filter display panel having the above structure are aligned and combined, and a liquid crystal material is injected and vertically aligned therebetween, the basic structure of the liquid crystal display according to the exemplary embodiment of the present invention is provided.

When the thin film transistor array panel and the color filter panel are aligned, the cutouts 271, 272, and 273 of the common electrode 270 divide the two pixel electrodes 190a and 190b into a plurality of sub-areas, respectively. In the present embodiment, as illustrated in FIG. 3, the two pixel electrodes 190a and 190b are respectively divided into four sub-regions. As can be seen in FIG. 3, each subregion is elongated to distinguish the width direction from the length direction.

The portion of the liquid crystal layer 3 between each subregion of the pixel electrodes 190a and 190b and the corresponding subregion of the reference electrode 270 is referred to as a subregion in the future, and these small regions are applied when an electric field is applied. It is classified into four types according to the average major axis direction of the liquid crystal molecules located therein, which is called domain in the future.

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 voltage of the second pixel electrode 190b changes due to capacitive coupling with the coupling electrode 176. Therefore, the absolute value of the voltage of the second pixel electrode 190b is always lower than that of the first pixel electrode 190b. As such, when two sub pixel electrodes having different voltages are disposed in one pixel area, the two sub pixel electrodes 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 one pixel of a liquid crystal display according to an exemplary embodiment of the present invention.

In FIG. 5, Clca represents a liquid crystal capacitor formed between the first pixel electrode 190a and the common electrode 270, and Cst represents a storage capacitor formed between the first pixel electrode 190a and the storage electrode line 131. . 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.

 On the other hand, by adjusting Ccp, the ratio of Vb to Va can be adjusted. The adjustment of Ccp is possible by adjusting the overlapping area and 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.

In the liquid crystal display according to the exemplary embodiment of the present invention, when the coupling capacitance of the two sub pixel electrodes or the area ratio of the two sub pixel electrodes is changed for each of red, green, and blue pixels, the voltage difference between the sub pixel electrodes or the sub pixel electrode is different. Transmittance, etc. will be different for each red, green, and blue pixel, which maximizes the color reproducibility of the memory color at any viewing angle, and maximizes the transmittance of the pixel, so that not only the side visibility but also the side visibility for a specific color. In this case, display characteristics may be improved, which will be described in detail with reference to the accompanying drawings. Here, the memory color means a color recognized in a human head, and when visibility is deteriorated with respect to such a color, visibility may be worse.

Next, a method of maximizing side visibility with respect to a specific color will be described in detail with reference to the accompanying drawings.

FIG. 6 is a gamma curve illustrating transmittance according to a gray voltage applied to a pixel. In this case, the solid line (-) is the front gamma curve at the front of the viewing angle of 0 °, the dotted line (…) is the gamma curve at the side without dividing the pixels, and the thick solid line (━) is the divided two sub-pixels. A side gamma curve of a pixel having an electrode, and a thick dotted line (…) represents a change in side gamma curve according to a change in voltage ratio or area ratio of two divided sub pixel electrodes.

As shown in FIG. 6, the side gamma curve (…) at the side having an arbitrary viewing angle is severely distorted compared to the front gamma curve (−) at the front having a viewing angle of 0 °. In order to solve this problem, the pixel electrode is divided into two sub-pixel electrodes so that different pixel voltages are applied, thereby inducing side gamma curves (??,…) closer to the front gamma curve (-) at an arbitrary viewing angle. This can improve visibility. In this case, the region A is a low gray voltage region, and the side gamma curve of the region A is mainly determined by the pixel voltage applied to the sub pixel electrode connected by the coupling capacitance, and the region B is the high gray voltage region, and the side gamma of the region B is The curve is mainly determined by the pixel voltage applied to the sub pixel electrode directly connected to the thin film transistor. In this case, the slope of the side gamma curve of the pixel by the sub pixel electrodes (the arrow in the diagonal direction) is determined by the voltage ratio applied to the two sub pixel electrodes, and the boundary between the region A and the region B (arrow in the horizontal direction, ↔) Is determined by the area ratio of the two sub pixel electrodes. Accordingly, the shape of the side gamma curve can be changed while changing the area ratio or voltage ratio of the sub pixel electrode in the red, green, and blue pixels, thereby maximizing side visibility for a specific color. This ensures stable color reproducibility. In other words, the area ratio or voltage ratio of the sub-pixel electrodes is adjusted so that the ratio of the luminance to the red, green, and blue gradations in the front gamma curve and the ratio of the luminance to the red, green, and blue gradations in the side gamma curve with respect to the memory color are the same. In other cases, side visibility can be maximized. The ratio of luminance to red, green and blue in the front gamma curve and the luminance to red, green and blue in the side gamma curve are the same for the performance yellow (skin color) in the memory color. The area ratios of the sub pixel electrodes 190a and 190b were changed differently. As a result, it is preferable that the area ratio of the second pixel electrode 190b to the first pixel electrode 190a in the green pixel is at least smaller than the red and blue pixels, and more preferably, to the first pixel electrode 190a. Preferably, the area ratio of the second pixel electrode 190b decreases in the order of blue, red, and green pixels.

In addition, in the pixel of the color of red, green, and blue which contributes greatly to the luminance, the area ratio of the sub pixel electrode which is connected with the coupling capacitance and has a relatively small luminance is reduced, and in the pixel of the color which contributes to the luminance, the thin film transistor It is possible to maximize the luminance of the pixel by designing a large area ratio of the sub pixel electrode which is directly connected and has a relatively large luminance.

The present invention can also be applied to a twisted nematic (TN) mode. This will be described in detail with reference to the drawings as another embodiment.

FIG. 7 is a layout view of a thin film transistor array panel for a liquid crystal display according to another exemplary embodiment. FIG. 8 is a cross-sectional view of the thin film transistor array panel of FIG. 7 taken along the line VIII-VIII ′.

A plurality of gate lines 121 and storage electrode lines 131 extending mainly in the horizontal direction are formed on the lower insulating substrate 110.

The gate line 121 has a plurality of portions extending up and down to form the gate electrode 124, and one end portion 129 is widely extended for connection with an external circuit.

Each storage electrode line 131 includes a plurality of storage electrodes 133a, 133b, and 133c extending therefrom. Two storage electrodes 133a and 133b of the pair of storage electrodes 133a, 133b, and 133c extend in the vertical direction and are connected to each other by another storage electrode 133c extending in the horizontal direction. In this case, each of the storage electrode lines 131 may be formed of two or more horizontal lines.

The gate line 121 and the storage electrode line 131 are made of metal such as Al, Al alloy, Ag, Ag alloy, Cr, Ti, Ta, Mo, or the like. In addition, the gate line 121 and the storage electrode line 131 may be made of various metals or conductors.

Side surfaces of the gate line 121 and the storage electrode line 131 are inclined, and the inclination angle with respect to the horizontal plane is 30-80 °.

A gate insulating layer 140 made of silicon nitride (SiNx) or the like is formed on the gate line 121 and the storage electrode line 131.

On the gate insulating layer 140, a plurality of data lines 171, a plurality of thin film transistor drain electrodes 175, a plurality of coupling electrodes 176, and a plurality of under-bridge metal pieces ( 172 is formed.

Each data line 171 extends mainly in a vertical direction, and forms a plurality of branches toward each drain electrode 175 to form a source electrode 173 of the thin film transistor.

The leg metal piece 172 is positioned on the gate line 121.

The coupling electrode 176 is connected to the drain electrode 175 and has different widths W _R , W _G , and W _{B for} each of the red (R), green (G), and blue (B) pixels. Here, the width of the coupling electrode 176 of the green (G) pixel is the widest, the coupling electrode 176 of the red (R) pixel is next, and the coupling electrode 176 of the blue (B) pixel is the narrowest. In this case, the coupling electrode has a horizontal portion 177 and a vertical portion 178 overlapping with the storage electrodes 133a and 133c, respectively.

Like the gate line 121, the data line 171, the drain electrode 175, the coupling electrode 176, and the leg metal piece 172 may be made of a material such as chromium and aluminum, and may be formed of a single layer or multiple layers. have.

Under the data line 171 and the drain electrode 175, a plurality of linear semiconductors 151 extending mainly vertically along the data line 171 are formed. Each linear semiconductor 151 made of amorphous silicon branches to the gate electrode 124, the source electrode 173, and the drain electrode 175 to form a channel 154 of the thin film transistor.

A plurality of ohmic contacts 161 are formed between the semiconductor 151 and the data line 171 and the drain electrode 175 to reduce the contact resistance between the two. The ohmic contact 161 is made of amorphous silicon doped with silicide or n-type impurities at a high concentration.

On the data line 171, the drain electrode 175, and the leg metal piece 172, a protective film 180 made of an inorganic insulator such as silicon nitride or an organic insulator such as resin is formed.

The passivation layer 180 includes a plurality of contact holes 181 and 182 exposing at least a portion of the drain electrode 175 and an end portion 179 of the data line 171, respectively, and the end of the gate line 121. A plurality of contact holes 181, 184, and 185 exposing portions of the portion 129 and the storage electrode line 131 penetrate the gate insulating layer 140 and the passivation layer 180, respectively.

A plurality of contact assistants 81 and 82 and a plurality of storage bridges 84 are formed on the passivation layer 180, as well as a plurality of pixel electrodes 190a and 190b. The pixel electrodes 190a and 190b, the contact assistants 81 and 82, and the connection legs 84 may be formed of a transparent conductor such as indium tin oxide (ITO) or indium zinc oxide (IZO), or a light reflection characteristic such as aluminum (Al). This excellent opaque conductor is made.

The pixel electrodes 190a and 190b are classified into the first pixel electrode 190a and the second pixel electrode 190b, and the first pixel electrode 190a is connected to the drain electrode 175 through the contact hole 185. The second pixel electrode 190b overlaps the coupling electrode 176. Therefore, the second pixel electrode 190b is electromagnetically coupled (capacitively coupled) to the first pixel electrode 190a. In this case, it is preferable that the coupling capacitance of the first pixel electrode 190a and the second pixel electrode 190b gradually decreases in the order of the green (G), red (R), and blue (B) pixels. In order to maximize visibility and transmittance with respect to color, the area ratio of the second pixel electrode 190b to the first pixel electrode 190 is preferably the smallest in the green pixel.

The first pixel electrode 190a and the second pixel electrode 190b are vertically divided based on the storage electrode 133c extending in the horizontal direction.

Further, on the passivation layer 180, a storage wiring connecting leg 84 is formed to connect the two storage electrode lines 131 that are positioned on both sides of the gate line 121. The storage wiring connection bridge 84 is in contact with the storage electrode 133a and the storage electrode line 131 through the contact holes 183 and 184 penetrating through the passivation layer 180 and the gate insulating layer 140. The sustain wiring connection leg 84 overlaps the leg metal piece 172. The storage wiring connection bridge 84 serves to electrically connect the entire storage electrode line 131 on the lower substrate 110. The storage electrode line 131 may be used to repair a defect of the gate line 121 or the data line 171, if necessary, and the metal part 172 of the bridge 121 may emit the gate line 121 when irradiating a laser for such repair. And to maintain the electrical connection of the retaining wire connecting bridge (84).

The contact auxiliary members 81 and 82 are connected to the end portion 129 of the gate line and the end portion 179 of the data line through the contact holes 181 and 182, respectively.

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

In addition, if the coupling capacitance or area ratio of the two sub pixel electrodes is different for each of the red, green, and blue pixels, the voltage difference between the two sub pixel electrodes is changed for each of the red, green, and blue pixels, thereby improving visibility by maximizing color reproducibility. It is possible to maximize the transmittance of the pixel.

In this case, the thin film transistor array panel may have a structure different from the above embodiment, and will be described in detail with reference to the accompanying drawings.

9 is a layout view illustrating a structure of a thin film transistor array panel according to another exemplary embodiment of the present invention. FIG. 10 is a cross-sectional view of the liquid crystal display including the thin film transistor array panel of FIG. 9 taken along the line X-X ′ of FIG. 9.

As shown in FIGS. 9 and 10, the layer structure of the thin film transistor array panel for the liquid crystal display device according to the present embodiment is generally the same as the layer structure of the thin film transistor array panel for liquid crystal display devices shown in FIGS. 1, 3, and 4. Do. That is, a plurality of gate lines 121 and storage electrode lines 131 including a plurality of gate electrodes 124 are formed on the substrate 110, and the gate insulating layer 140 and the plurality of protrusions 154 are formed thereon. A plurality of linear semiconductors 151, a plurality of linear ohmic contacts 161 each including a plurality of protrusions 163, and a plurality of island-type ohmic contacts 165 are 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, 185, 181, 183, and 184 are formed in the passivation layer 180 and / or the gate insulating layer 140, and the plurality of first and second pixel electrodes 190a, 190b) and a plurality of contact assisting members 81 and 82 are formed.

However, unlike the thin film transistor array panel illustrated in FIGS. 1, 3, and 4, in the thin film transistor array panel according to the present exemplary embodiment, the semiconductor 151 may include the data line 171 except for the protrusion 154 in which the thin film transistor is located. The planar shape is substantially the same as the drain electrode 175 and the ohmic contacts 161 and 165 below. In detail, the linear semiconductor 151 may include the source electrode 173 and the drain electrode 175 in addition to the data line 171, the drain electrode 175, and the portions below the ohmic contacts 161 and 165. ) Has an exposed portion between them.

Of course, the thin film transistor array panel for the liquid crystal display according to the present exemplary embodiment includes the coupling electrode 176, and the amorphous silicon layers 154 and 165 are formed under the coupling electrode 176 in the same shape.

In the method of manufacturing the thin film transistor array panel, similarly to the case of patterning the passivation layer 190, a photoresist pattern having a different thickness is formed.

FIG. 11 is a layout view of a thin film transistor array panel for a liquid crystal display according to another exemplary embodiment. FIG. 12 is a cross-sectional view taken along the line XII-XII ′ of FIG. 11.

As shown in Figs. 11 and 12, the layer structure of the thin film transistor array panel for liquid crystal display according to the present embodiment is generally the same as the layer structure of the thin film transistor array panel for liquid crystal display shown in Figs.

However, as shown in FIGS. 9 and 10, in the thin film transistor array panel according to the present exemplary embodiment, the semiconductor 151 may include the data line 171 and the drain electrode 175 except for the protrusion 154 where the thin film transistor is located. And substantially the same planar shape as the resistive contact members 161 and 165 thereunder. In detail, the linear semiconductor 151 may include the source electrode 173 and the drain electrode 175 in addition to the data line 171, the drain electrode 175, and the portions below the ohmic contacts 161 and 165. ) Has an exposed portion between them.

Through the above configuration, the side visibility may be improved in the liquid crystal display, and in particular, the visibility may be improved for a specific color and the transmittance of the pixel may be maximized.                     

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. In particular, the arrangement of the cutouts formed in the pixel electrode and the common electrode may be variously modified.

Claims (14)

Insulation board, A plurality of first signal lines formed on the insulating substrate, A plurality of second signal lines insulated from and intersecting the first signal lines; A first pixel electrode formed for each of a plurality of pixels defined by the crossing of the first signal line and the second signal line; A thin film transistor disposed in each of the pixels and having three terminals connected to the first signal line, the second signal line, and the first pixel electrode, respectively; A second pixel electrode formed in each of the pixels and capacitively coupled to the first pixel electrode Wherein the pixel comprises red, green, and blue pixels, wherein the ratio of luminance to red, green, and blue gradations in the front gamma curve and the ratio of luminance to red, green, and blue gradations of the lateral gamma curve The thin film transistor array panel of claim 1, wherein the first pixel electrode and the second pixel electrode have different area ratios in red, blue, and green pixels. In claim 1, The area ratio of the second pixel electrode to the first pixel electrode is smaller than the red and blue pixels at least in the green pixel. In claim 1, The area ratio of the second pixel electrode to the first pixel electrode decreases in order of the blue, red, and green pixels. In claim 1, The coupling capacitor is different from each other in the red, green, and blue pixels. In claim 1, And a coupling electrode connected to the first pixel electrode and overlapping the second pixel electrode in an insulated state. In claim 5, The area of the coupling electrode polymerized with the second pixel electrode decreases in the order of green, red, and blue pixels. In claim 1, And at least one of the first pixel electrode and the second pixel electrode has domain dividing means. A plurality of first signal lines, a plurality of second signal lines insulated from and intersecting the first signal lines, a first pixel electrode formed for each of a plurality of pixels defined by crossing the first signal line and the second signal line, each of the pixels A thin film transistor having three terminals connected to the first signal line, the second signal line, and the first pixel electrode, respectively, formed in each of the pixels and capacitively coupled to the first pixel electrode; A thin film transistor array panel comprising a second pixel electrode, and An opposing display panel on which opposing electrodes are formed to face the first and second pixel electrodes to form an electric field; Wherein the pixel comprises red, green, and blue pixels, wherein the ratio of luminance to red, green, and blue gradations in the front gamma curve and the ratio of luminance to red, green, and blue gradations of the lateral gamma curve And the first pixel electrode and the second pixel electrode have different area ratios or voltage ratios to the opposite electrodes in the red, blue, and green pixels. In claim 8, The area ratio of the second pixel electrode to the first pixel electrode is smaller than the red and blue pixels at least in the green pixel. In claim 8, The area ratio of the second pixel electrode to the first pixel electrode decreases in order of the blue, red, and green pixels. In claim 1, The coupling capacitance is different in the red, green, and blue pixels. In claim 8, And a coupling electrode connected to the first pixel electrode and overlapping the second pixel electrode in an insulated state. In claim 12, The area of the coupling electrode polymerized with the second pixel electrode decreases in the order of green, red, and blue pixels. In claim 8, And at least one of the first and second pixel electrodes and the counter electrode has domain dividing means.

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