KR20070003288A - Liquid crystal divice - Google Patents

Abstract

An LCD is provided to prevent static electricity from being concentrated on cutout portions of a pixel electrode, by forming storage electrodes below the cutout portions of the pixel electrode. A gate line is formed on a first substrate(110). A storage electrode line has a plurality of storage electrodes(133a). A data line crosses the gate line and the storage electrode line. A thin film transistor is electrically connected to the gate line and the data line. A passivation layer(180) covers the thin film transistor. The passivation layer is formed of an organic layer, and has a flat surface. A pixel electrode(191) is formed on the passivation layer, and has a plurality of cutout portions(92,93a,94a). The storage electrodes overlap the cutout portions, respectively.

Description

Liquid crystal display {LIQUID CRYSTAL DIVICE}

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

FIG. 2 is a layout view of a thin film transistor array panel for the liquid crystal display of FIG. 1.

FIG. 3 is a layout view of a common electrode display panel for the liquid crystal display of FIG. 1.

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

* Description of Drawing Symbols *

7: notch 11, 21: alignment layer

12, 22: polarizer 81, 82: contact auxiliary member

71, 72, 73a, 73b, 74a, 74b, 75a, 75b, 91, 92, 93a, 93b, 94a, 94b, 95a, 95b: incision

110 and 210: insulated substrate 121: gate line

131: sustain electrode lines 133a to 133c: sustain electrode

154: semiconductor 161, 165: ohmic contact member

171: data line 175: drain electrode

180: protective film 181, 182, 185: contact hole

191: pixel electrode

220: light blocking member 230: color filter

250: overcoat 270: common electrode

The present invention relates to a thin film transistor array panel, and more particularly, to a thin film transistor array panel for a liquid crystal display device.

The liquid crystal display is one of the most widely used flat panel display devices, and includes two display panels on which a field generating electrode such as a pixel electrode and a common electrode are formed, and a liquid crystal layer interposed therebetween. The liquid crystal display generates an electric field in the liquid crystal layer by applying a voltage to the field generating electrode, thereby determining an orientation of the liquid crystal molecules of the liquid crystal layer and controlling the polarization of incident light to display an image.

One of the two display panels includes a plurality of wirings such as a gate line and a data line, a thin film transistor that controls a data signal transmitted to the pixel electrode and the pixel electrode, and the other display panel includes a common electrode and a color filter facing the pixel electrode. Formed.

In this case, the thin film transistor array panel is easily exposed to static electricity generated during the manufacturing process because the transparent insulating substrate on which the plurality of wirings are formed is an insulator, and the static electricity is locally present on the substrate. Even if a small amount of static electricity is introduced, the voltage is increased by being locally present in the introduced part, thereby damaging the vulnerable areas of static electricity.

In particular, in the case of a liquid crystal display including an incision, static electricity is mainly concentrated in the incision to damage the incision.

In order to solve this problem, an alignment film and a polarizing plate which have been treated with an antistatic treatment are used, but this has a problem of high cost.

Therefore, the technical problem of the present invention is to prevent the static electricity from being driven into the incision without increasing the cost by using the alignment film and the polarizing plate which is not subjected to the antistatic treatment.

The liquid crystal display according to the present invention for achieving the above technical problem is a first substrate, a gate line formed on the first substrate, a sustain electrode line formed on the first substrate and having a plurality of sustain electrodes, on the first substrate A thin film transistor which is formed and intersects the gate line and the storage electrode line, the thin film transistor connected to the gate line and the data line, and covers the thin film transistor, and is formed of an organic material, and has a flat protective film, and is formed on the protective film, A pixel electrode is included and the sustain electrode overlaps the cutout.

The shielding electrode may further include a shielding electrode formed on the passivation layer and separated from the pixel electrode. The shielding electrode may overlap the data line and be wider than the width of the data line.

The cutout forms an oblique angle with the gate line and the data line, and an angle formed by the cutout and the gate line may be 45 °.

The sustain electrode may include a plurality of oblique portions that form an oblique angle with the gate line and the data line, and the oblique portions may form 45 ° with the gate line.

The storage electrode may further include a vertical portion connecting a portion of the diagonal portion and overlapping the side of the pixel electrode.

The sustain electrode may further include an extension part connected to the diagonal part and the vertical part.

A second substrate facing the first substrate, a light blocking member formed on the second substrate, a color filter formed on the light blocking member, and a common electrode formed on the color filter and having a cutout, wherein the cutout of the common electrode It may be arranged alternately with the cutout of the pixel electrode.

Hereinafter, exemplary 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, layer, area, plate, etc. is over another part, this includes not only the part directly above the other part but also another part in the middle. On the contrary, when a part is just above another part, it means that there is no other part in the middle.

Next, a liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4.

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

1 to 4, a liquid crystal display according to an exemplary embodiment of the present invention includes a thin film transistor array panel 100 and a common electrode panel 200 facing each other and between the two display panels 100 and 200. The liquid crystal layer 3 is included.

First, the thin film transistor array panel 100 will be described with reference to FIGS. 1, 2, and 4.

A plurality of gate lines 121 and a plurality of storage electrode lines 131 are formed on an insulating substrate 110 made of transparent glass or plastic.

The gate line 121 transmits a gate signal and mainly extends in a horizontal direction. Each gate line 121 includes a plurality of gate electrodes 124 protruding upwards and a wide end portion 129 for connection with another layer or an external driving circuit. A gate driving circuit (not shown) for generating a gate signal may be mounted on a flexible printed circuit film (not shown) attached to the substrate 110 or directly mounted on the substrate 110, It may be integrated into the substrate 110. When the gate driving circuit is integrated on the substrate 110, the gate line 121 may extend to be directly connected to the gate driving circuit.

The storage electrode line 131 receives a predetermined voltage and almost extends in parallel with the gate line 121. Each storage electrode line 131 is positioned between two adjacent gate lines 121 and is substantially equal to the two gate lines 121. The storage electrode line 131 connects the expanded portion 137 extending up and down, the plurality of diagonal portions 133a and 133b extending from the expanded portion 137 and the vertical portion 133c connecting the diagonal portions 133a and 133b. It includes a plurality of sustain electrode set including. Diagonal portions 133a and 133b extend obliquely up and down from extension portion 137. However, the shape and arrangement of the storage electrode line 131 may be modified in various ways.

The gate line 121 and the storage electrode line 131 may be formed of aluminum-based metal such as aluminum (Al) or aluminum alloy, silver-based metal such as silver (Ag) or silver alloy, copper-based metal such as copper (Cu) or copper alloy, or molybdenum ( It may be made of molybdenum-based metals such as Mo) or molybdenum alloy, chromium (Cr), tantalum (Ta) and titanium (Ti). However, they may have a multilayer structure including two conductive films (not shown) having different physical properties. One of the conductive films is made of a metal having low resistivity, such as aluminum-based metal, silver-based metal, or copper-based metal, so as to reduce signal delay or voltage drop. On the other hand, other conductive films are made of other materials, especially materials having excellent physical, chemical and electrical contact properties with indium tin oxide (ITO) and indium zinc oxide (IZO), such as molybdenum-based metals, chromium, tantalum, and titanium. Good examples of such a combination include a chromium bottom film, an aluminum (alloy) top film, and an aluminum (alloy) bottom film and a molybdenum (alloy) top film. However, the gate line 121 and the storage electrode line 131 may be made of various other metals or conductors.

Side surfaces of the gate line 121 and the storage electrode line 131 are inclined with respect to the surface of the substrate 110, and the inclination angle is preferably about 30 to 80 °.

A gate insulating layer 140 made of silicon nitride (SiN _x ) or silicon oxide (SiOx) is formed on the gate line 121 and the storage electrode line 131.

On the gate insulating layer 140, a plurality of island semiconductors 154 made of hydrogenated amorphous silicon (amorphous silicon is abbreviated as a-Si), polycrystalline silicon, or the like are formed. A plurality of island type ohmic contacts 163 and 165 are formed on the semiconductor 154. The ohmic contacts 163 and 165 may be made of a material such as n + hydrogenated amorphous silicon in which n-type impurities such as phosphorus are heavily doped, or may be made of silicide. The ohmic contacts 163 and 165 are paired and disposed on the semiconductor 154.

Side surfaces of the semiconductor 154 and the ohmic contacts 163 and 165 are also inclined with respect to the surface of the substrate 110, and the inclination angle is about 30 to 80 °.

A plurality of data lines 171 and a plurality of drain electrodes 175 are formed on the ohmic contacts 163 and 165 and the gate insulating layer 140.

The data line 171 transmits a data voltage and mainly extends in the vertical direction to cross the gate line 121 and the storage electrode line 131. Each data line 171 includes a plurality of source electrodes 173 extending toward the gate electrode 124 and a wide end portion 179 for connection with another layer or an external driving circuit. The source electrode 173 becomes narrower from bottom to top, and then widens again to have a concave mortar shape.

A data driving circuit (not shown) for generating a data voltage is mounted on a flexible printed circuit film (not shown) attached to the substrate 110, directly mounted on the substrate 110, or integrated in the substrate 110. Can be. When the data driving circuit is integrated on the substrate 110, the data line 171 may be extended to be directly connected to the data driving circuit.

Each drain electrode 175 is separated from the data line 171, and is divided into two bifurcated bent portions 176 around the source electrode 173 and a wide end portion 177 connected to the bent portions 176. It includes. Bent portion 176 and wide end portion 177 are connected by rod-shaped connection 178. The wide end portion 177 overlaps the storage electrode 137, and both ends of the curved portion 176 are surrounded by the concave portion of the source electrode 173.

One gate electrode 124, one source electrode 173, and one drain electrode 175 together with the protrusion 154 of the semiconductor 151 form one thin film transistor (TFT). A channel of the transistor is formed in the protrusion 154 between the source electrode 173 and the drain electrode 175.

The data line 171 and the drain electrode 175 are preferably made of a refractory metal such as molybdenum, chromium, tantalum, and titanium, or an alloy thereof, and include a refractory metal film (not shown) and a low resistance conductive film. It may have a multilayer structure including (not shown). Examples of the multilayer structure include a double layer of chromium or molybdenum (alloy) lower layer and an aluminum (alloy) upper layer, and a triple layer of molybdenum (alloy) lower layer and aluminum (alloy) interlayer and molybdenum (alloy) upper layer. However, in addition to the data line 171 and the drain electrode 175, it may be made of various metals or conductors.

It is preferable that the side surfaces of the data line 171 and the drain electrode 175 are inclined at an inclination angle of about 30 to 80 degrees with respect to the surface of the substrate 110.

The ohmic contacts 163 and 165 exist only between the semiconductor 151 below and the data line 171 and the drain electrode 175 thereon, thereby lowering the contact resistance.

A passivation layer 180 is formed on the data line 171, the drain electrode 175, and the exposed semiconductor 151. The passivation layer 180 may include a lower layer 180p made of an inorganic insulator such as silicon nitride or silicon oxide, and an upper layer 180q made of an organic insulator. The organic insulator preferably has a dielectric constant of 4.0 or less, may have photosensitivity, and provide a flat surface. The passivation layer 180 may have a single layer structure made of an organic insulator. As such, when the passivation layer 180 is formed of an organic insulator, a step may not be generated due to the wiring at the bottom thereof, thereby making the top flat. Therefore, since the arrangement of the liquid crystal molecules is not distorted in the conventional stepped portion, light leakage due to the stepped portion can be prevented.

In the passivation layer 180, a plurality of contact holes 182 and 185 exposing the end portion 179 and the drain electrode 175 of the data line 171 are formed, respectively, and the passivation layer 180 and the gate insulating layer are formed. A plurality of contact holes 181 exposing the end portion 129 of the gate line 121 are formed at 140.

A plurality of pixel electrodes 191, a shielding electrode 88, and a plurality of contact assistants 81 and 82 are formed on the passivation layer 180. They may be made of a transparent conductive material such as ITO or IZO or a reflective metal such as aluminum, silver, chromium or an alloy thereof.

The pixel electrode 191 is physically and electrically connected to the drain electrode 175 through the contact hole 185 and receives a data voltage from the drain electrode 175. The pixel electrode 191 to which the data voltage is applied is generated between the two electrodes 191 and 270 by generating an electric field together with the common electrode 270 of the other display panel 200 to which the common voltage is applied. The direction of the liquid crystal molecules 31 of the liquid crystal layer 3 is determined. The polarization of light passing through the liquid crystal layer 3 varies according to the direction of the liquid crystal molecules 31 determined as described above. The pixel electrode 191 and the common electrode 270 form a capacitor (hereinafter, referred to as a "liquid crystal capacitor") to maintain an applied voltage even after the thin film transistor is turned off.

The pixel electrode 191 overlaps the storage electrode line 131 including the storage electrode 137. A capacitor formed by the pixel electrode 191 and the drain electrode 175 electrically connected to the pixel electrode 191 overlapping the storage electrode line 131 is called a storage capacitor, and the storage capacitor enhances the voltage holding capability of the liquid crystal capacitor.

Each pixel electrode 191 has a substantially rectangular shape in which four corners are chamfered, and the chamfered hypotenuse forms an angle of about 45 ° with respect to the gate line 121.

The pixel electrode 191 includes first and second central cutouts 91 and 92, lower cutouts 93a, 94a and 95a, and upper cutouts 93b, 94b and 95b, and the pixel electrode 191. ) Is divided into a plurality of partitions by these cutouts 91 to 95b. The cutouts 91 to 95b have almost inverted symmetry with respect to the sustain electrode line 131. The lower and upper cutouts 93a, 93b, 94a, 94b, 95a, and 95b extend obliquely from the right side of the pixel electrode 191 to the left side, left corner, lower side, or upper side. The lower and upper cutouts 93a-95b are positioned at the lower half and the upper half with respect to the storage electrode line 131, respectively. The lower and upper cutouts 93a-95b extend perpendicular to each other at an angle of about 45 ° with respect to the gate line 121.

The first central cutout 91 extends along a horizontal centerline of the pixel electrode 191 and has an inlet at a left side thereof. The inlet of the first central incision 91 has a pair of hypotenuses that are substantially parallel to the lower incisions 93a, 94a, 95a and the upper incisions 93b, 94b, 95b, respectively. The second central cutout 92 includes a central cross section and a pair of diagonal lines. The central horizontal portion extends from the right side of the pixel electrode 191 to the left along the storage electrode line 131, and the pair of diagonal portions respectively cuts the lower and upper portions toward the left side of the pixel electrode 191 at the end of the central horizontal portion. It extends almost in parallel with the parts 93a-95b.

Accordingly, the lower half of the pixel electrode 191 is divided into five regions by the central cutout 92 and the lower cutouts 93a, 93b, and 94a, and the upper half also includes the center cutout 92 and the upper cutout. The sections 94b, 95a, and 95b are divided into five regions. In this case, the number of regions or the number of cutouts may vary depending on the size of the pixel, the ratio of the length of the horizontal side to the vertical side of the pixel electrode, and the type or characteristics of the liquid crystal layer 3.

The diagonal, lower and upper cutouts 93a-95b of the second center cutout 92 of the pixel electrode 191 overlap the diagonals 133a and 133b of the storage electrode set. In this case, the width of the cutouts 91 to 95b of the pixel electrode 191 may be wider than the widths of the oblique portions 133a and 133b of the storage electrode line 131. When the cutouts 92-95b and the inclined portions 133a and 133b overlap each other, the electric charge is discharged through the inclined portions 133a and 133b of the sustain electrode line 131 rather than the charge being charged toward the cutout portions 92-95b. Therefore, the damage by the electrostatic discharge can be prevented.

The shielding electrode 88 receives a common voltage and includes a vertical portion extending along the data line 171 and a horizontal portion extending along the gate line 121. The vertical portion completely covers the data line 171, and the horizontal portion connects the adjacent vertical portions and is located inside the boundary line of the gate line 121. The shielding electrode 88 blocks electromagnetic interference between the data line 171 and the pixel electrode 191 and between the data line 171 and the common electrode 270 to prevent voltage distortion and the data line 171 of the pixel electrode 191. Reduces the signal delay of the data voltage delivered by

The contact auxiliary members 81 and 82 are connected to the end portion 129 of the gate line 121 and the end portion 179 of the data line 171 through the contact holes 181 and 182, respectively. The contact auxiliary members 81 and 82 compensate for and protect the adhesion between the end portions 179 and 129 of the data line 171 and the gate line 121 and the external device.

Next, the common electrode display panel 200 will be described with reference to FIGS. 1, 3, and 4.

A light blocking member 220 is formed on an insulating substrate 210 made of transparent glass, plastic, or the like. The light blocking member 220 is also called a black matrix and prevents light leakage. The light blocking member 220 includes a linear portion 221 corresponding to the data line 171 and a planar portion 222 corresponding to the thin film transistor, and prevents light leakage between the pixel electrodes 191 and prevents the pixel electrode 191. Define the facing opening area. However, the light blocking member 220 may have a plurality of openings (not shown) facing the pixel electrode 191 and having substantially the same shape as the pixel electrode 191.

A plurality of color filters 230 is also formed on the substrate 210. The color filter 230 is mostly present in an area surrounded by the light blocking member 230, and may extend in the vertical direction along the column of the pixel electrodes 191. Each color filter 230 may display one of primary colors such as three primary colors of red, green, and blue.

An overcoat 250 is formed on the color filter 230 and the light blocking member 220. The overcoat 250 may be made of an (organic) insulator, which prevents the color filter 230 from being exposed and provides a flat surface. The overcoat 250 may be omitted.

The common electrode 270 is formed on the overcoat 250. The common electrode 270 is made of a transparent conductor such as ITO or IZO.

The plurality of cutouts 71, 72, 73a, 73b, 74a, 74b, 75a, and 75b are formed in the common electrode 270.

One set of cutouts 71 to 75b faces the pixel electrode 191 and faces the first and second central cutouts 71 and 72, the lower cutouts 73a, 73b and 74a, and the upper cutout ( 74b, 75a, 75b). Each of the cutouts 71 to 75b is disposed between the adjacent cutouts 91-95b of the pixel electrode 191 or between the cutouts 91-95b and the concave hypotenuse of the pixel electrode 191. In addition, each cutout 71 to 75b includes at least one diagonal line extending in parallel with the lower cutouts 93a, 94a and 95a or the upper cutouts 93b, 94b and 95b of the pixel electrode 191.

Each of the upper and lower incisions 73a, 73b, 74a, 74b, 75a, 75b includes an oblique portion and a horizontal portion or a longitudinal portion. The diagonal portion extends from the right side of the pixel electrode 191 to the lower side, the upper side, or the left side of the pixel electrode 191. The horizontal portion or the vertical portion extends from each end of the diagonal portion along the side of the pixel electrode 191 and forms an obtuse angle with the diagonal portion.

The central cutouts 71, 72 comprise a central transverse section, a pair of oblique sections and a pair of longitudinal longitudinal sections. The central horizontal portion extends from the right side of the pixel electrode 191 to the left along the horizontal center line of the pixel electrode 191, and the pair of diagonal portions respectively lower toward the left side of the pixel electrode 191 at the end of the central horizontal portion. And almost parallel with the upper incisions 73a-75b. The vertical vertical portion extends along each side of the pixel electrode 191 from each end of the diagonal portion and forms an obtuse angle with the diagonal portion. The number and direction of the cutouts 71 to 75b may also vary depending on design factors.

Each of the cutouts 71 to 75b of the common electrode 270 includes a notch 7 in which an oblique portion is concave.

Alignment layers 11 and 21 are coated on inner surfaces of the display panels 100 and 200, and they may be vertical alignment layers. Polarizers 12 and 22 are provided on the outer surfaces of the display panels 100 and 200, and the transmission axes of the two polarizers 12 and 22 are perpendicular to each other, and one of the transmission axes is parallel to the gate line 121. desirable. In the case of a reflective liquid crystal display, one of the two polarizers 12 and 22 may be omitted. In the present invention, a polarizer having no antistatic treatment can be used by effectively removing the static electricity flowing into the cutout by forming the sustain electrode under the cutout of the pixel electrode.

The liquid crystal display may include a polarizer 12 and 22, display panels 100 and 200, and a backlight unit (not shown) that supplies light to the liquid crystal layer 3.

The liquid crystal layer 3 has negative dielectric anisotropy, and the liquid crystal molecules of the liquid crystal layer 3 are aligned such that their major axes are perpendicular to the surfaces of the two display panels 100 and 200 in the absence of an electric field. Therefore, incident light does not pass through the quadrature polarizers 12 and 22 and is blocked.

The cutouts 71 to 75b and 91 to 95b of the field generating electrodes 191 and 270 and the sides of the pixel electrode 191 distort the electric field to create horizontal components that determine the inclination direction of the liquid crystal molecules. The horizontal component of the electric field is substantially perpendicular to the sides of the cutouts 71 to 75b and 91 to 95b and the sides of the pixel electrode 191.

On the other hand, the notch formed in the cutouts 71 to 75b prevents the inclination direction of the liquid crystal molecules from being arbitrarily determined, and the reaction time is accelerated by easily determining the inclination direction of the liquid crystal molecules.

Referring to FIG. 1, one set of cutouts 71 to 75b and 91 to 95b divides the pixel electrode 191 into a plurality of sub-areas, and each sub-region is a main portion of the pixel electrode 191. It has two major edges forming an oblique angle with the sides. Most of the liquid crystal molecules on each subregion are inclined in a direction perpendicular to the periphery thereof, and thus, the inclination directions are approximately four directions. As described above, when the liquid crystal molecules are inclined in various directions, the reference viewing angle of the liquid crystal display is increased.

The shape and arrangement of the cutouts 71-75b and 91-95b can be modified.

As described above, the present invention can prevent light leakage due to the step by removing the step due to the wiring by using the organic insulating film. In addition, by forming the sustain electrode under the cutout, static electricity does not collect in the cutout, so that the alignment film and the polarizer do not need to be subjected to the antistatic treatment, thereby reducing production costs.

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.

Claims (10)

First substrate, A gate line formed on the first substrate, A storage electrode line formed on the first substrate and having a plurality of storage electrodes; A data line formed on the first substrate and crossing the gate line and the storage electrode line; A thin film transistor connected to the gate line and the data line, A protective film covering the thin film transistor and having a flat surface made of an organic material, and A pixel electrode formed on the passivation layer and having a plurality of cutouts; Including The sustain electrode overlaps the cutout. Liquid crystal display. In claim 1, And a shielding electrode formed on the passivation layer and separated from the pixel electrode. In claim 2, The shielding electrode overlaps the data line and is wider than the width of the data line. In claim 1, And the cutout forms an oblique angle with the gate line and the data line. In claim 4, And an angle formed between the cutout portion and the gate line is 45 °. In claim 1, The sustain electrode includes a plurality of oblique portions formed at an oblique angle with the gate line and the data line. In claim 6, The diagonal portion forms a 45 ° angle with the gate line. In claim 6, The storage electrode further includes a vertical portion connecting a portion of the diagonal portion and overlapping a side of the pixel electrode. In claim 8, The sustain electrode further includes an extension part connected to a portion of the oblique part and the vertical part. In claim 1, A second substrate facing the first substrate, A light blocking member formed on the second substrate, A color filter formed on the light blocking member; A common electrode formed on the color filter and having a cutout More, The cutout portion of the common electrode is alternately arranged with the cutout portion of the pixel electrode.

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