KR102328918B1 - Array substrate and liquid cristal display device including thereof - Google Patents

Abstract

One embodiment according to the present invention is a thin film transistor; a common electrode disposed between the first and second insulating layers; and a pixel electrode disposed on the second insulating layer, wherein the pixel electrode includes: a contact part electrically connected to the thin film transistor; an extension portion extending from the contact portion and having a slit; and a first auxiliary electrode extending from the contact portion in a boundary region between the contact portion and the extension portion, wherein the first auxiliary electrode strengthens the electric torque of the liquid crystal at the boundary area between the contact portion and the extension portion to increase the electric field By preventing the distortion line from moving to the light emitting region, it is possible to prevent a decrease in transmittance.

Description

Array substrate and liquid crystal display including same {ARRAY SUBSTRATE AND LIQUID CRISTAL DISPLAY DEVICE INCLUDING THEREOF}

The present invention relates to an array substrate and a liquid crystal display including the same.

In general, a thin film transistor (TFT) is widely used as a switching element in a thin film transistor liquid crystal display (TFT LCD), which is a semiconductor device and a display device. Among them, the thin film transistor liquid crystal display device is spotlighted as a next-generation high-tech display device with low power consumption, good portability, technology-intensive, and high added value.

Among these liquid crystal displays, an active matrix liquid crystal display equipped with a thin film transistor, which is a switching element that can control the on and off of voltage for each pixel, has the most attention due to its excellent resolution and video realization ability. are receiving

The liquid crystal display includes a color filter substrate (ie, an upper substrate) having a common electrode, an array substrate (ie, a lower substrate) having pixel electrodes, and liquid crystal filled between the upper and lower substrates. In the device, the liquid crystal is driven by an electric field applied vertically between the common electrode and the pixel electrode, and characteristics such as transmittance and aperture ratio are excellent. However, liquid crystal driving by an electric field applied vertically has a disadvantage in that the viewing angle characteristic is not excellent. Therefore, a newly proposed technology to overcome these disadvantages is a liquid crystal driving method using a transverse electric field.

In such a lateral liquid crystal display device, a color filter substrate and an array substrate are configured to face each other, and a liquid crystal layer is interposed between the color filter substrate and the array substrate. The array substrate includes a thin film transistor, a common electrode, and a pixel electrode for each of a plurality of pixels defined on a transparent insulating substrate. In addition, the common electrode and the pixel electrode are configured to be spaced apart from each other in parallel on the same substrate. In the color filter substrate, a black matrix is formed in a portion corresponding to the gate wiring, the data wiring, and the thin film transistor on a transparent insulating substrate, and a color filter is formed in correspondence to the pixel. The liquid crystal layer is driven by a horizontal electric field between the common electrode and the pixel electrode. In the transverse electric field type liquid crystal display device having the above configuration, the common electrode and the pixel electrode are generally formed of transparent electrodes in order to secure luminance. Accordingly, a technology proposed to maximize the luminance improvement effect is an Advanced High In Plane Switching (AH-IPS) technology. However, in AH-IPS, in a region where the electric field direction is not uniform, a region in which the liquid crystal is driven in a direction that does not contribute to transmittance and a region in which the liquid crystal is driven in a direction opposite to each other causes discrelation ( Disclination) region, that is, an electric field distortion region occurs, and transmittance and contrast ratio of the liquid crystal display device are lowered, so that the liquid crystal display device has a problem in that display quality is deteriorated.

An embodiment according to the present invention may provide an array substrate capable of reducing a driving voltage by reducing a thickness of an insulating layer between a pixel electrode and a common electrode, and a liquid crystal display including the same.

In addition, another embodiment according to the present invention may provide an array substrate capable of realizing transmittance and a good viewing angle by forming a storage capacitor through fringe field driving, and a liquid crystal display including the same.

In addition, another embodiment according to the present invention may provide an array substrate capable of reducing electric field distortion by applying a single-domain sub-pixel structure and a liquid crystal display including the same.

In addition, another embodiment according to the present invention may provide an array substrate capable of realizing high distortion and low tilt angle through negative liquid crystal driving and a liquid crystal display including the same.

In addition, another embodiment according to the present invention may provide an array substrate capable of improving transmittance by preventing an electric field distortion line from increasing a driving voltage, and a liquid crystal display including the same.

One embodiment according to the present invention is a thin film transistor;

a common electrode having a first insulating layer interposed therebetween; and a pixel electrode, wherein the pixel electrode includes: a contact part electrically connected to the thin film transistor; an extension portion extending from the contact portion and having a slit; and a first auxiliary electrode extending from the contact portion in a boundary region between the contact portion and the extension portion, wherein the first auxiliary electrode strengthens the electric torque of the liquid crystal at the boundary area between the contact portion and the extension portion to increase the electric field By preventing the distortion line from moving to the light emitting region, it is possible to prevent a decrease in transmittance.

In another embodiment according to the present invention, the extension part and the first auxiliary electrode are bent in a first direction at different acute angles based on a normal to a gate line providing a gate signal to the thin film transistor, and the contact By extending from the part, it is possible to realize the optimal transmittance according to the driving voltage.

Also, in another embodiment according to the present invention, the extension part and the first auxiliary electrode are extended in a direction away from the gate line, so that the first auxiliary electrode strengthens the electrical torque of the liquid crystal at the boundary region between the contact part and the extension part. It is possible to control the transmittance resistance region not to move.

In addition, another embodiment according to the present invention further includes a second auxiliary electrode extending from the contact portion in a boundary region between the contact portion and the extension portion in a direction closer to a gate line providing a gate signal to the thin film transistor. Accordingly, in addition to the first auxiliary electrode, it is possible to increase the electrical torque of the liquid crystal in the boundary region between the contact portion and the extension portion.

In another embodiment according to the present invention, the extension portion and the first auxiliary electrode have different acute angles from each other based on a normal to a gate line providing a gate signal to the thin film transistor, and the extension portion is oriented in the first direction. bent, the second auxiliary electrode is bent at an acute angle with respect to the normal in a second direction opposite to the first direction to extend from the contact portion, and from the contact portion of the first or second auxiliary electrode The extended length may be smaller than the length extended from the contact part of the extension part to realize optimal transmittance according to the driving voltage.

In addition, another embodiment according to the present invention may further include a second insulating layer that is an organic insulating layer disposed between the thin film transistor and the common electrode to reduce parasitic capacitance such as capacitance between the pixel electrode and the data line. It is possible to reduce the thickness of the second insulating layer, thereby reducing the driving voltage for forming an electric field between the pixel electrode and the common electrode, thereby reducing power consumption.

In addition, another embodiment according to the present invention is a thin film transistor; and a pixel electrode including a contact portion electrically connected to a portion of the thin film transistor, an extension portion extending from the contact portion, and an auxiliary electrode extending from the contact portion in a boundary region between the contact portion and the extension portion By providing the array substrate, the auxiliary electrode makes the electric torque of the liquid crystal in the boundary region between the contact portion and the extension portion strong so that the electric field distortion line does not move to the light emitting region, thereby preventing a decrease in transmittance.

In another embodiment according to the present invention, the array substrate includes a first region corresponding to a black matrix on a color filter substrate facing the array substrate and a second region excluding the first region, and the auxiliary electrode includes: By disposing in the first region, it is possible to prevent the electric field distortion line formed in the non-emission region, which is the first region, around the second region, which is the emission region, from moving into the second region.

In another embodiment according to the present invention, the first and second insulating layers; and a common electrode disposed between the first and second insulating layers and facing the pixel electrode, wherein the pixel electrode is disposed on the second insulating layer and overlaps the common electrode so as to be different from each other. Light emitting efficiency may be increased according to fringe field driving between the pixel electrode and the common electrode disposed on the layer. In addition, since the storage capacitor may be formed on the opening of the pixel electrode, an extra storage capacitor is not required, so that high transmittance and high resolution with good viewing angle characteristics may be realized.

Also, in another embodiment according to the present invention, the extension portion is bent in a first direction from the contact portion at a first acute angle with respect to a normal to a gate line providing a gate signal to the thin film transistor and is separated from the gate line. direction, the first acute angle is 5 degrees to 9 degrees, and the auxiliary electrode is bent from the contact part in the first direction at a second acute angle with respect to the normal line in the first direction and is connected to the gate line to extend from the contact part in a direction away from it, and the auxiliary electrode is bent in a second direction opposite to the first direction from the contact part at a third acute angle with respect to the normal line and approaches the gate line By extending from the contact part, it is possible to implement an optimal transmittance according to the driving voltage.

Also, in another embodiment according to the present invention, the auxiliary electrode includes first and second auxiliary electrodes, and the first auxiliary electrode is directed from the contact portion in the first direction at a second acute angle with respect to the normal line. The second auxiliary electrode is bent and extended from the contact part in a direction away from the scan line, and the second auxiliary electrode is bent from the contact part at a third acute angle with respect to the normal line in a second direction opposite to the first direction. to extend from the contact part in a direction closer to the scan line, and the second acute angle and the third acute angle are greater than the first acute angle to increase the electrical torque of the liquid crystal in the boundary region between the contact part and the extended part to increase the transmittance resistance While controlling the region to not move, it is possible to realize optimal transmittance according to the driving voltage.

Further, in another embodiment according to the present invention, since the extension part has a slit, luminous efficiency according to fringe field driving between the pixel electrode 110 and the common electrode 120 disposed on different layers can increase In addition, since the storage capacitor Cst may be formed on the opening 115 of the pixel electrode 110 , an extra storage capacitor is not required, thereby realizing high resolution with high transmittance and good viewing angle characteristics.

In addition, another embodiment according to the present invention, the above-described array substrate; and a color filter substrate facing the array substrate and having a black matrix and a color filter, wherein the array substrate is divided into a first region facing the black matrix and a second region facing the color filter, The first auxiliary electrode is a display panel disposed in the first region and a liquid crystal display device for fringe field driving of the display panel. The first auxiliary electrode maximizes the luminance improvement effect and prevents movement of the electric field distortion region, thereby resisting transmittance. to improve display quality.

In one embodiment according to the present invention, the response speed of the liquid crystal can be improved by reducing the driving voltage by reducing the thickness of the insulating layer between the pixel electrode and the common electrode, thereby reducing power consumption and forming a high electric field even under the same driving voltage. , by forming a storage capacitor through fringe field driving, transmittance and good viewing angle can be realized, electric field distortion can be reduced by applying a single domain structure sub-pixel structure, and high distortion and low tilt angle can be realized through negative liquid crystal driving It is possible to provide an array substrate capable of improving transmittance by preventing the electric field distortion line from increasing the driving voltage, and a liquid crystal display including the same.

1 is a view showing a liquid crystal display including an array substrate according to an embodiment of the present invention.
2 is a schematic plan view of sub-pixels of an array substrate 101;
Fig. 3 is a schematic cross-sectional view taken along line AB of Fig. 2;
4 and 5 are plan views of a pixel electrode and an auxiliary electrode on the array substrate according to the first embodiment of the present invention;
6 and 7 are plan views of a pixel electrode and an auxiliary electrode on an array substrate according to a second exemplary embodiment of the present invention.
8 is a plan view of a pixel electrode and an auxiliary electrode on an array substrate according to a third exemplary embodiment of the present invention;
9 to 11 are diagrams illustrating electric field distortion when a pixel electrode does not include an auxiliary electrode;
12 to 14 and 16 to 18 are views illustrating electric field distortion when a pixel electrode includes an auxiliary electrode.
15 and 19 are experimental data comparing transmittance according to a driving voltage of a pixel electrode including an auxiliary electrode with a reference.

Hereinafter, an array substrate according to an embodiment of the present invention and a liquid crystal display including the same will be described in detail with reference to the drawings. The embodiments introduced below are provided as examples so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the embodiments described below and may be embodied in other forms. And, in the drawings, the size and thickness of the device may be exaggerated for convenience. Like reference numbers refer to like elements throughout.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout. The sizes and relative sizes of layers and regions in the drawings may be exaggerated for clarity of description.

The terminology used herein is for the purpose of describing the embodiments, and thus is not intended to limit the present invention. As used herein, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, “comprise” and/or “comprising” refers to the presence of one or more other components, steps, operations, and/or elements mentioned. or addition is not excluded.

1 is a view showing a liquid crystal display including an array substrate according to an embodiment of the present invention.

Referring to FIG. 1 , a liquid crystal display 10 according to an embodiment of the present invention includes a display panel 100 , a timing controller 200 , a data driving circuit 300 , and a gate driving circuit 400 .

The display panel 100 includes liquid crystal molecules disposed between two substrates. In the display panel 100 , m*n (m, n is a positive integer) sub-pixel regions are defined in a matrix form by an intersecting structure of the data lines D1 to Dm and the gate lines G1 to Gn. and liquid crystal cells Clc are disposed in each of the sub-pixel areas.

In addition, the sub-pixel region defined by the intersection of the plurality of gate lines and the plurality of data lines includes a first sub-pixel displaying a first color, a second sub-pixel displaying a second color, and a third sub-pixel displaying a third color. It may include a pixel and may additionally include a fourth sub-pixel displaying a fourth color. The first to third sub-pixels may display red, green, and blue colors, and the fourth sub-pixel may display white colors.

The array substrate 101 of the display panel 100 includes m data lines D1 to Dm, n gate lines G1 to Gn, a common line CL, a thin film transistor (TFT), and a T ), a sub-pixel including a pixel electrode 110 , a common electrode 120 , and a storage capacitor Cst of the liquid crystal cell Clc respectively connected to the TFTs may be formed, and the color of the display panel 100 . A black matrix and a color filter may be formed on the filter substrate 102 . A polarizing plate may be attached to each of the color filter substrate 102 and the array substrate 101 of the display panel 100 , and an alignment layer for setting a pretilt angle of the liquid crystal may be formed on the inner surface in contact with the liquid crystal.

The data driving circuit 300 may include a plurality of data driver integrated circuits. The data driving circuit 300 latches digital video data (mRGB) under the control of the timing controller 200 and converts the digital video data into analog positive/negative gamma compensation voltages to generate positive/negative data voltages. do. Each of the plurality of data driver integrated circuits may provide a data signal to each of the plurality of grouped data lines D1 to Dm. Accordingly, the number of the data driver integrated circuits may vary according to the degree of grouping of the data driver integrated circuits according to the resolution of the liquid crystal display device. In addition, the data driving circuit 300 may supply a data voltage to the data lines D1 to Dm during each horizontal period in which the source output enable signal SOE is maintained at a low logic level. In addition, the data driver integrated circuits may be mounted on a tape carrier package (TCP) and bonded to the array substrate 101 of the display panel 100 by a tape automated bonding (TAB) process.

The gate driving circuit 400 includes a shift register, a level shifter for converting the output signal of the shift register into a swing width suitable for driving the TFT of the liquid crystal cell, and an output buffer connected between the level shifter and the gate lines G1 to Gn. includes The gate driving circuit 400 sequentially supplies gate signals having a pulse width of approximately one horizontal period to the gate lines G1 to Gn under the control of the timing controller 200 . The gate driving circuit 400 is mounted on the TCP and bonded to the array substrate 101 of the display panel 100 by the TAB process, or the array substrate 101 simultaneously with the pixel array by the GIP (Gate driver in panel) process. ) can be formed directly on the

The timing controller 200 converts digital video data (RGB) input from a system board (not shown) into mRGB video data, rearranges it to fit the display panel 100 , and supplies it to the data driving circuit 300 . The timing controller 200 receives timing signals such as vertical/horizontal synchronization signals (Vsync, Hsync), data enable, and clock signal CLK from the system board, and receives the data driving circuit 300 and the gate driving circuit Control signals GCS and DCS for controlling the operation timing of 400 are generated. In addition, when the display panel 100 includes a fourth sub-pixel displaying a white color, digital video data (RGB) is converted into mRGBW video data, and it is rearranged to fit the display panel 100 to provide the data driving circuit 300 . can supply

The gate timing control signal GCS for controlling the gate driving circuit 400 includes a gate start pulse (GSP), a gate shift clock (GSC), a gate output enable signal (Gate Output Enable, GOE) and the like. The gate start pulse GSP is generated once during one frame period at the same time as the start of the frame period to generate the first gate pulse. The gate shift clock GSC is a clock signal commonly input to a plurality of stages constituting the shift register and shifts the gate start pulse GSP. The gate output enable signal GOE controls the output of the gate driving circuit 400 .

The data timing control signal DCS for controlling the data driving circuit 300 includes a source start pulse (SSP), a source sampling clock (SSC), a vertical polarity control signal (Polarity, POL) and and a source output enable signal (Source Output Enable, SOE). The source start pulse SSP is a signal that controls the data sampling start timing of the data driving circuit 300 , and the source sampling clock SSC corresponds to a rising or falling edge in each IC constituting the data driving circuit 300 . A clock signal that controls the sampling timing of data. In addition, the vertical polarity control signal Polarity POL controls the vertical polarity inversion timing of the data voltage output from the data driving circuit 300 for each gate line G1 to Gn, and the source output enable signal SOE is It serves to control the output timing of the data driving circuit 300 . The data driving circuit 300 latches mRGB DATA input under the control of the timing controller 200 . Then, the vertical polarity control signal (Polarity, POL) is converted into an analog positive or negative gamma compensation voltage (GAMMA) and simultaneously output to the display panel 100 through all data lines D1 to Dm. Specifically, the data driving circuit 300 may set the polarity of the data voltage output from the data driving circuit 300 to a positive polarity when the vertical polarity control signal POL provided from the timing controller 200 is high logic. , when the logic is low, the polarity of the data voltage output from the data driving circuit 300 may be negative. In addition, the polarity may be inverted in units of vertical lines by the vertical polarity control signal POL.

FIG. 2 is a schematic plan view of sub-pixels of the array substrate 101 , and FIG. 3 is a schematic cross-sectional view taken along line A-B of FIG. 2 .

2 and 3 , the array substrate 101 may be a transparent insulating substrate, and a data line DL extending in a first direction on the array substrate 101 and the array substrate 101 . and a gate line GL extending along the second direction and crossing the data line DL. The data line DL may have a bent structure in a boundary region between sub-pixel regions, and thus may have a zigzag shape along the first direction. Accordingly, the first sub-pixel regions 101a on the first horizontal line in the second direction and the first sub-pixel regions 101a on the second horizontal line adjacent to the first horizontal line in the first direction are vertical lines. The data line DL may have a bent shape near the boundary area between the second sub-pixel areas 101b. In addition, the array substrate 101 includes a common line CL extending in a second direction, a large-area common electrode 120 electrically connected to the common line CL, the plurality of data lines DL, and A gate electrode GE and an active layer ACT are provided at intersections of the plurality of gate lines GL and extend from the gate lines GL, and a source electrode SE extends from the data line DL. and a thin film transistor T including a drain electrode DE and a pixel electrode 110 electrically connected to the thin film transistor T and overlapping the large-area common electrode 120 . In addition, the common electrode 120 may be formed as a tubular electrode, and a pixel electrode 110 , which is a pattern electrode, may be disposed on the common electrode 120 . In addition, a first auxiliary electrode 131 extending from the pixel electrode 110 may be included. A common electrode 120 is disposed on the first insulating layer 130 of the array substrate 101 , a second insulating layer 140 is disposed on the common electrode 120 , and the second insulating layer 140 . The first auxiliary electrode 131 and the pixel electrode 110 may be disposed thereon. As described above, the common electrode 120 and the pixel electrode 110 are disposed on the array substrate 101 , but are disposed on different layers with the second insulating layer 140 interposed therebetween, and the pixel electrode 110 is The pixel electrode top structure may be disposed on a layer higher than the common electrode 120 .

As such, in the pixel electrode top structure, the common electrode 120 having a larger area than the pixel electrode 110 is disposed on the lower surface of the pixel electrode 110 , so that the common electrode 120 is the pixel electrode 110 . ), the thickness of the second insulating layer 140 may be further reduced than in the common electrode top structure disposed on a higher layer. Specifically, since the pixel electrode 110 occupies a smaller area than the common electrode 120 , in the top structure, the second insulating layer 140 on the first insulating layer 130 on which the pixel electrode 110 is not disposed is thick. because it loses In addition, by reducing the thickness of the second insulating layer 140, the electric field on the second insulating layer 140 is strengthened, so the driving voltage can be reduced. This has the advantage of improving speed.

The pixel electrode 110 and the common electrode 120 overlap each other, and the pixel electrode 110 has an opening 115 that is a slit, so that it may become a pattern electrode. In addition, the slit, which is the opening 115 , may have a shape corresponding to the extension part 112 (to be described later) of the pixel electrode 110 .

Meanwhile, luminous efficiency may be increased according to fringe field driving between the pixel electrode 110 and the common electrode 120 disposed on different layers. In addition, since the storage capacitor Cst may be formed on the opening 115 of the pixel electrode 110 , an extra storage capacitor is not required, thereby realizing high resolution with high transmittance and good viewing angle characteristics.

Also, the first insulating layer 130 may be an organic insulating layer. Since the first insulating layer 130 is made of an organic material, parasitic capacitance such as capacitance between the pixel electrode 110 and the data line DL can be reduced, so that the thickness of the second insulating layer 140 is reduced. can be reduced In addition, as the thickness of the second insulating layer 140 is reduced, a driving voltage for forming an electric field between the pixel electrode 110 and the common electrode 120 is reduced, thereby reducing power consumption.

Also, the sub-pixels may have a single domain structure. Since each of the sub-pixels has a single domain structure, the liquid crystal may rotate in one direction. As described above, since the sub-pixels have a single domain structure rather than a dual domain, a problem of a decrease in transmittance due to a disclination phenomenon occurring in a boundary region of the dual domain can be solved.

On the other hand, the liquid crystal may be divided into positive and negative types, and the liquid crystal applied to the liquid crystal display of the present invention may be of a negative type. As described above, by applying the negative type liquid crystal, the transmittance can be improved by realizing a high twist and a low tilt angle.

4 and 5 are plan views of the pixel electrode and the auxiliary electrode on the array substrate according to the first embodiment of the present invention, and FIGS. 6 and 7 are the pixel electrode and the auxiliary electrode on the array substrate according to the second embodiment of the present invention. 8 is a plan view of a pixel electrode and an auxiliary electrode on an array substrate according to a third embodiment of the present invention.

4 and 5 , the pixel electrode 110 on the array substrate 101 according to the first embodiment includes a contact part 111 and an extension part 112 , and the contact part 111 includes a contact part. A region electrically connected to the drain electrode DE through a hole and may have a rectangular shape. In addition, the extension part 112 may be formed to extend from the contact part 111 as a partial region of the pixel electrode 110 branched from the contact part 111 , and the extension part 112 may include the contact part. It may include a first extension part 113 extending from 111 and a second extension part 114 extending from the first extension part 113 . The first extension part 113 extends from the contact part 111 while being bent to the left or right, and the second extension part 114 extends from the first extension part 113 to the first extension part 113 . It may be formed while being bent more than the first extension part 113 in the same direction as the bending direction. In addition, a boundary region between the first extension part 113 and the second extension part 114 is formed so that the pixel electrode 110 has a single domain structure in a light emitting region that does not correspond to the black matrix BM. It may be inside a region corresponding to the black matrix BM.

In addition, the extension part 112 may be inclined to the left on the odd-numbered horizontal line, and may be inclined to the right on the even-th horizontal line. In addition, when the extension 112 is inclined to the right on the even-th horizontal line, it is inclined to the left on the odd-numbered horizontal line, so the bending directions of each of the extensions on the odd-numbered and even-numbered horizontal lines may be opposite to each other. have. In addition, the extension portion 112 may be disposed to be inclined toward the data line DL in response to the bending direction. As described above, the sub-pixels on the horizontal line are arranged to be alternately bent left or right in the vertical direction, so that the transmittance can be uniformly maintained through the cancellation of the electric field distortion between the horizontal lines.

The contact part 111 and the extension part 112 may be integrally formed by the same process, and an opening 115 may be formed in the extension part 112 to have a pattern shape. Although one opening 115 is formed in the drawing, it is not limited thereto and may be formed in plurality, and the opening 115 may have a shape corresponding to the shape of the extension part 112 . In addition, the pixel electrode 110 may further include a first auxiliary electrode 131 , and the first auxiliary electrode 131 may be formed branching from the contact unit 111 , and can be part of In particular, the first auxiliary electrode 131 extends from the contact part 111 to the extension part 112 in the boundary region between the contact part 111 and the extension part 112 among the edge regions of the extension part 112 . It may extend in the same direction as the direction. That is, when the extension part 112 extends upward with respect to the display panel 100 , the first auxiliary electrode 131 may extend upward. As described above, the first auxiliary electrode 131 is inclined in a direction corresponding to the bending direction of the extension portion 112 to increase the electrical torque energy in the boundary region between the extension portion 112 and the contact portion 111 . The rotation of the liquid crystal on the boundary region and the region adjacent to the boundary region may be balanced.

The first extension portion 113 may extend from the contact portion 111 while being bent at an acute angle a to the left or right with respect to the normal H perpendicular to the gate line GL. And the angle a may be 5 to 9 degrees, preferably 7 degrees in consideration of the electric field distortion. In this case, 7 degrees refers not only to exactly 7 degrees, but also to approximately 7 degrees in consideration of errors in the process. In addition, the second extension portion 114 may be bent from the first extension portion 113 at an angle greater than the angle a with respect to the normal line H.

The first auxiliary electrode 131 may extend in the same direction as the extension portion 112 , and is disposed on a region indicated by a dotted line of the array substrate 101 corresponding to the black matrix BM disposed on the color filter substrate. can be placed. That is, the first auxiliary electrode 131 may face the black matrix BM. Specifically, in the color filter substrate 102 facing the array substrate 101 and having a black matrix BM and a color filter CF, the array substrate 101 faces the black matrix BM It is divided into a first area and a second area facing the color filter CF, the contact part 111 and the first auxiliary electrode 131 may be disposed in the first area, and the extension part 112 may be disposed in the first area. ) may be disposed to correspond to the first and second regions. As described above, by disposing the first auxiliary electrode 131 in the first region, it is possible to prevent the electric field distortion line formed in the non-emission region, which is the first region, around the second region, which is the emission region, from moving into the second region. have. The first and the first auxiliary electrodes 131 are formed of the contact part 111 when the extension part 112 is bent to the left like the pixel electrode on the sub-pixel of the first sub-pixel regions 101a of FIG. 2 . It may be formed in an upper left corner region, that is, in a left corner region adjacent to a point where the contact unit 111 and the extension part 112 meet among the corner regions of the contact part 111 , and the extension part 112 is When bent to the right like the pixel electrode on the sub-pixel of the second sub-pixel regions 101b of FIG. 2 , the contact part is located at the upper right corner of the contact part 111 , that is, in the corner region of the contact part 111 . It may be formed in a right corner area adjacent to a point where the 111 and the extended part 112 meet.

The first auxiliary electrode 131 may be bent at an acute angle b in the same direction as the direction in which the extension part 112 is bent based on the normal line H perpendicular to the gate line GL. The angle b may be 30 degrees to 60 degrees, but preferably 45 degrees in consideration of electric field distortion. In this case, 45 degrees not only refers to exactly 45 degrees, but also refers to approximately 45 degrees in consideration of process errors.

6 and 7 , the pixel electrode 110 on the array substrate 101 according to the second embodiment is the same as that of the first embodiment except for the second auxiliary electrode 132 , and thus is the same as that of the first embodiment. A detailed description of the same effect as the configuration will be omitted. The pixel electrode 110 may further include a second auxiliary electrode 132 , and the second auxiliary electrode 132 may be formed to be branched from the contact unit 111 . can be part of In particular, the second auxiliary electrode 132 extends from the contact part 111 to the extension part 112 in the boundary region between the contact part 111 and the extension part 112 among the edge regions of the extension part 112 . It may extend in a direction opposite to the direction. That is, when the extension part 112 extends upward with respect to the display panel 100 , the second auxiliary electrode 132 may extend downward.

The second auxiliary electrode 132 may extend in a direction different from that of the extension part 112 . That is, when the extension part 112 extends in the upper direction, the second auxiliary electrode 132 may extend in the lower direction. In addition, the second auxiliary electrode 132 may be disposed on a region indicated by a dotted line of the array substrate 101 corresponding to the black matrix BM disposed on the color filter substrate. That is, the second auxiliary electrode 132 may face the black matrix BM. Specifically, in the color filter substrate 102 facing the array substrate 101 and having a black matrix BM and a color filter CF, the array substrate 101 faces the black matrix BM It is divided into a first area and a second area facing the color filter CF, the contact part 111 and the second auxiliary electrode 132 may be disposed in the first area, and the extension part 112 may be disposed in the first area. ) may be disposed to correspond to the first and second regions. . As described above, by disposing the second auxiliary electrode 132 in the first region, it is possible to prevent the electric field distortion line formed in the non-emission region, which is the first region around the second region, which is the emission region, from moving into the second region. have. In addition, the second auxiliary electrode 132 is the right side of the lower portion of the contact unit 111 when the extension 112 is bent to the left like the pixel electrode on the sub-pixel of the first sub-pixel areas 101a of FIG. 2 . It may be formed in a corner region, that is, in a right corner region adjacent to a point where the contact unit 111 and the extension part 112 meet among the corner regions of the contact part 111, and the extension part 112 is shown in FIG. When the second sub-pixel regions 101b are bent to the right like the pixel electrode on the sub-pixel, the contact unit 111 is a lower left corner region of the contact unit 111 , that is, among the corner regions of the contact unit 111 . and the extension part 112 may be formed in a left corner area adjacent to the meeting point. As described above, the second auxiliary electrode 132 is inclined in a downward direction opposite to the bending direction of the extended portion 112 so that the extended portion 112 and the second auxiliary electrode 132 are within a predetermined range. By making them parallel, electric torque energy may be increased in the boundary region between the extension portion 112 and the contact portion 111 to balance the rotation of the liquid crystal on the boundary region and an adjacent region of the boundary region. The second auxiliary electrode 132 may be bent at an acute angle b with respect to the normal line H perpendicular to the gate line GL. The angle b may be 30 degrees to 60 degrees, but preferably 45 degrees in consideration of electric field distortion. In this case, 45 degrees not only refers to exactly 45 degrees, but also refers to approximate 45 degrees in consideration of process errors.

In addition, when the first and second auxiliary electrodes 131 and 132 are extended, they may extend up to the black matrix BM-corresponding area within the adjacent sub-pixel area, and may not extend to the transmissive area of the adjacent sub-pixel area. Thus, it is possible to prevent an influence on the liquid crystal driving of the adjacent sub-pixel area.

Referring to FIG. 8 , the pixel electrode 110 on the array substrate 101 according to the third exemplary embodiment is the same as the first and second exemplary embodiments except for the first and second auxiliary electrodes 131 and 132 . A detailed description of the same configuration and the same effect as those of the first and second embodiments will be omitted. The pixel electrode 110 may further include first and second auxiliary electrodes 131 and 132 , and the first and second auxiliary electrodes 131 and 132 are described in the first and second embodiments, respectively. The first and second auxiliary electrodes 131 and 132 may be formed to extend from the contact portion 111 in the same manner.

Meanwhile, the first and second auxiliary electrodes 131 and 132 may have a bar type shape. In addition, the length of the first and second auxiliary electrodes 131 and 132 extending from the contact part 111 may be smaller than the length of the extension part 112 extending from the contact part 111 , The ratio of completed roads may range from 1:8 to 12.

An improvement in electric field distortion according to the auxiliary electrode will be described with reference to FIGS. 9 to 19 .

9 to 11 illustrate electric field distortion when the pixel electrode does not include an auxiliary electrode, and FIGS. 12 to 14 and 16 to 18 illustrate electric field distortion when the pixel electrode includes an auxiliary electrode. 15 and 19 are experimental data comparing transmittance according to a driving voltage of a pixel electrode including an auxiliary electrode with a reference.

Referring to FIG. 9 , the liquid crystal fails to rotate or maintains the initial state in the displayed region in a low driving voltage state, so that a region in which transmittance is reduced due to electric field distortion occurs, and as shown in FIG. 10 , the peak driving voltage and 11, as the driving voltage exceeds the peak, the transmittance lowering region due to electric field distortion rises in the direction of the arrow, and eventually rises to the region corresponding to the color filter CF except for the black matrix BM, that is, the transmissive region. Transmittance of the light emitting region may be reduced.

Specifically, to explain the decrease in transmittance due to electric field distortion, liquid crystal molecules maintaining an initial state are transverse to the liquid crystal layer in the 0 degree direction with respect to the plane of the array substrate 101 due to the electric field generated in the array substrate 101 . Although only an electric field should be applied, due to the rectangular shape of the pixel electrode 110 structure limited to a specific width and height, the upper and lower boundary regions of the pixel electrode 110 have a direction other than the 0 degree lateral electric field (0 to 0). 360 degrees) is generated. And liquid crystal molecules rotated in a specific direction (reference counterclockwise direction: liquid crystals rotated by a 0 degree electric field thereafter are defined as counterclockwise rotation) by a transverse electric field in the 0 degree direction inside the pixel electrode 110 and The liquid crystal molecules rotate in the direction opposite to the specific direction by the electric field from 0 to 360 degrees (reference clockwise: liquid crystals rotated by an electric field other than 0 degrees thereafter are defined as rotating clockwise). In the middle region of the region of the liquid crystal molecules rotated in different directions, a region in which liquid crystal molecules maintaining an initial alignment direction state that do not rotate in either direction are present. The non-rotating liquid crystal molecules cause a decrease in transmittance in the sub-pixel, and a region or region and line in which the transmittance does not occur may be generated. The field distortion line may occur under specific conditions, such as a specific voltage or higher, and high temperature. After the field distortion line is generated, the field distortion line moves from the outside to the inside of the sub-pixel and a desired specific transmittance when the voltage and the specific condition are maintained after a time passes. can not maintain the resolution, and the transmittance is lowered, thereby reducing the resolution. In addition, the electric field distortion line is generated in the edge region of the extension part 112 , particularly in the boundary region between the contact part 111 and the extension part 112 , and as the driving voltage rises, the extension part 112 is inside, that is, the inside of the light emitting region. to decrease the transmittance. However, as can be seen from the low driving voltage state of FIG. 12 , the peak driving voltage state of FIG. 13 , and the peak driving voltage state of FIG. 14 , the first auxiliary electrode 131 may Transmittance resistance region due to electric field distortion by making the electrical torque energy of the region with non-rotating liquid crystal molecules near the arranged region stronger than the electrical torque energy of the region with liquid crystals rotating clockwise and counterclockwise You can control it to not move. Accordingly, as shown in the graph of FIG. 15 , when the first auxiliary electrode 131 is provided compared to the reference Ref. without the first auxiliary electrode 131 , the transmittance is greatly improved.

In addition, as can be seen from the low driving voltage state of FIG. 16 , the peak driving voltage state of FIG. 17 , and the peak driving voltage state of FIG. 18 , the first auxiliary electrode 131 and the second auxiliary electrode 132 are applied together In the same case, the liquid crystal rotating in the clockwise and counterclockwise directions uses the electrical torque energy of the region where the liquid crystal molecules do not rotate near the region where the first auxiliary electrode 131 and the second auxiliary electrode 132 are disposed. By making the electric torque energy stronger than the electric torque energy of the region, the transmittance resistance region due to the electric field distortion can be controlled so that the black matrix BM does not correspond, that is, it does not move into the light emitting region of the color filter CF region. Therefore, as shown in the graph of FIG. 19 , when the first and second auxiliary electrodes 131 and 132 are provided compared to the reference (Ref.) without the first and second auxiliary electrodes 131 and 132, transmittance is greatly improved. There is an advantage.

In addition, as can be seen from the comparison of FIGS. 15 and 19 , when the second auxiliary electrode 132 is additionally provided in addition to the first auxiliary electrode 131 , higher transmittance is exhibited under the same voltage.

On the other hand, acute angles b and c of the first and second auxiliary electrodes 131 and 132 applied in the experimental examples of FIGS. 15 and 19 are 45 degrees, the acute angle a of the extension part 112 is 7 degrees, and the first and second auxiliary electrodes 131 and 132 are 45 degrees. 2 The ratio of the length extended from the contact part 111 of each of the auxiliary electrodes 131 and 132 to the length extended from the contact part 111 of the extension part 112 is 1:10, and thus the optimum transmittance according to the driving voltage It is a value determined by considering the phenomenon that the transmittance falls at the driving voltage exceeding the peak and the peak.

In the detailed description of the present invention described above, it has been described with reference to preferred embodiments of the present invention, but those skilled in the art or those having ordinary knowledge in the technical field of the present invention described in the claims to be described later It will be understood that various modifications and variations of the present invention can be made without departing from the spirit and scope of the present invention. Accordingly, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

100 display panel
110 pixel electrode
111 contact part
112 extension
113 first extension
114 second extension
115 slit, opening
120 common electrode
130 first insulating layer
131 first auxiliary electrode
132 second auxiliary electrode
140 second insulating layer
200 timing controller
300 data driver
400 gate driver

Claims (20)

a data line extending in a first direction that is a vertical direction;
a gate line extending in a second direction perpendicular to the first direction;
a common line extending in the second direction and spaced apart from the gate line;
a thin film transistor disposed at an intersection of the gate line and the data line;
a common electrode electrically connected to the common line and formed of a tubular electrode;
a first insulating layer disposed on the common electrode; and
a pixel electrode disposed on the first insulating layer and overlapping the common electrode;
The pixel electrode is
a contact part electrically connected to the thin film transistor;
an extension portion extending from the contact portion and having a slit; and
a first auxiliary electrode extending from the contact portion in a boundary region between the contact portion and the extension portion;
The extension part is inclined at a first angle that is an acute angle with respect to the first direction, and the first extension part extends from the contact part, and the extension part is inclined at a second angle greater than the first angle with respect to the first direction. having a second extension extending from the first extension;
The first auxiliary electrode is branched from the contact portion and extends to be inclined at a third angle greater than the first angle with respect to the first direction. According to claim 1,
The first angle is 5 degrees to 9 degrees, and the third angle is 30 degrees to 60 degrees. According to claim 1,
The extension portion and the first auxiliary electrode extend in a direction away from the gate line. According to claim 1,
and a second auxiliary electrode extending from the contact portion in a boundary region between the contact portion and the extension portion in a direction closer to a gate line providing a gate signal to the thin film transistor. 5. The method of claim 4,
A direction in which the extension portion and the first auxiliary electrode extend from the contact portion and a direction in which the second auxiliary electrode extends from the contact portion are opposite to each other. 6. The method of claim 5,
A length in which the first or second auxiliary electrode extends from the contact portion is smaller than a length in which the extension portion extends from the contact portion. According to claim 1,
The array substrate further comprising a second insulating layer that is an organic insulating layer disposed between the thin film transistor and the common electrode. thin film transistor; and
a pixel electrode including a contact portion electrically connected to a portion of the thin film transistor, an extension portion extending from the contact portion, and an auxiliary electrode extending from the contact portion in a boundary region between the contact portion and the extension portion;
The extension portion is inclined at a first acute angle with respect to the vertical direction and extends from the contact portion,
The auxiliary electrode extends from a corner region of an upper portion of the contact unit, and extends to be inclined at an angle greater than the first acute angle with respect to the vertical direction. 9. The method of claim 8,
the array substrate includes a first region corresponding to a black matrix on a color filter substrate facing the array substrate and a second region excluding the first region;
and the auxiliary electrode is disposed in the first region. 9. The method of claim 8,
first and second insulating layers; and a common electrode disposed between the first and second insulating layers and facing the pixel electrode;
The pixel electrode is disposed on the second insulating layer and overlaps the common electrode. 9. The method of claim 8,
The extension portion is bent in a first direction from the contact portion at the first acute angle with respect to a normal to a gate line providing a gate signal to the thin film transistor and extends from the contact portion in a direction away from the gate line. . 12. The method of claim 11,
The first acute angle is 5 to 9 degrees of the array substrate. 12. The method of claim 11,
The auxiliary electrode is bent from the contact portion in the first direction at a second acute angle greater than the first acute angle with respect to the normal line and extends from the contact portion in a direction away from the gate line. 12. The method of claim 11,
The auxiliary electrode is bent in a second direction opposite to the first direction from the contact portion at a third acute angle greater than the first acute angle with respect to the normal line and extends from the contact portion in a direction closer to the gate line. array substrate. 12. The method of claim 11,
The auxiliary electrode includes first and second auxiliary electrodes,
The first auxiliary electrode is bent from the contact portion in the first direction at a second acute angle greater than the first acute angle with respect to the normal line and extends from the contact portion in a direction away from the scan line,
The second auxiliary electrode is bent in a second direction opposite to the first direction from the contact portion at a third acute angle greater than the first acute angle with respect to the normal line, and the contact portion is closer to the scan line. an array substrate extending from delete delete 9. The method of claim 8,
The extension portion is an array substrate having a slit. The array substrate according to claim 1; and
and a color filter substrate facing the array substrate and having a black matrix and a color filter;
the array substrate is divided into a first area facing the black matrix and a second area facing the color filter;
The first auxiliary electrode is disposed in the first area. The display panel according to claim 19, including
A liquid crystal display for fringe field driving of the display panel.

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