KR102563200B1 - Liquid crystal display device - Google Patents

Abstract

The present invention relates to a liquid crystal display device capable of effectively discharging static electricity in a liquid crystal display device to which a plastic front cover is applied. A bottom cover accommodating the liquid crystal panel and the light source unit and a discharge pattern disposed on the liquid crystal panel to be fastened to the bottom cover and floating at a position corresponding to the non-display area of the liquid crystal panel on an inner surface facing the liquid crystal panel. included front case. The front case is preferably made of a plastic material.

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY DEVICE}

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device that can effectively discharge static electricity in a liquid crystal display device to which a plastic front cover is applied.

Recently, with the development of various portable electronic devices such as mobile phones, PDAs, and notebook computers, a demand for a flat panel display device for light, thin, and short devices that can be applied thereto is gradually increasing. As such flat panel display devices, LCD (Liquid Crystal Display), PDP (Plasma Display Panel), FED (Field Emission Display), VFD (Vacuum Fluorescent Display) are being actively researched, but mass production technology, ease of driving means, high-definition For reasons of implementation, a liquid crystal display (LCD) is now in the limelight. Among them, in recent years, an in-plane switching mode (IPS mode) liquid crystal display having a wide viewing angle characteristic has been applied to actual mass production and is widely used. The IPS mode liquid crystal display includes at least one pair of pixel electrodes and a common electrode arranged in parallel within a pixel. These pixel electrodes and the common electrode align liquid crystal molecules on a plane by generating a transverse electric field.

In such an IPS mode liquid crystal display, since both the pixel electrode and the common electrode are positioned on the lower substrate, only a color filter is formed on the upper substrate, and no separate conductive material is formed. Due to this, the conventional IPS mode liquid crystal display has a problem of whitening due to electrostatic discharge (ESD) generated toward the upper substrate. In order to solve this problem, a conductive pattern made of a transparent conductive material is provided on the upper surface of the upper substrate, and the conductive pattern and the ground pattern of the lower substrate are connected through a conductive dot, so that the static electricity applied to the upper substrate An IPS mode liquid crystal display in which static electricity is discharged toward a ground pattern of a substrate and additionally provided with a metal front case so that the static electricity is discharged toward the metal front case has been proposed. However, since the weight and manufacturing cost of a liquid crystal display having a metal front case increase as the size of the display screen increases, attempts are being made to replace it with materials such as plastic. In this case, static electricity generated on the upper substrate cannot be applied to the plastic front case, and static electricity is generated in a region of the upper substrate that is closer to the lower substrate than the distance to the conductive dot or static electricity having a high voltage level is generated. When this occurs, the static electricity is not discharged toward the conductive dot but directly applied toward the closer lower substrate, thereby causing defects in the thin film transistor positioned on the lower substrate.

The present invention has been made to solve the above problems, and in particular, to provide a liquid crystal display device capable of effectively discharging static electricity in a liquid crystal display device to which a plastic front cover is applied.

In order to solve the above problems, a liquid crystal display device according to the present invention, a liquid crystal panel, a light source unit located on the rear surface of the liquid crystal panel, a bottom cover accommodating the liquid crystal panel and the light source unit, and liquid crystal to be fastened to the bottom cover and a front case disposed on the panel and provided with a discharge pattern floating at a position corresponding to a non-display area of the liquid crystal panel on an inner surface opposite to the liquid crystal panel. The front case is preferably made of a plastic material.

A ground pattern may be provided on a lower substrate of the liquid crystal panel, and a conductive pattern may be provided on an upper surface of the upper substrate, and the conductive pattern and the ground pattern are connected to each other by metal dots formed through the upper substrate.

The liquid crystal display according to the present invention has an effect of greatly reducing the peak voltage of static electricity according to experiments by forming a discharge pattern on the inner surface of the front case. That is, according to the present invention, since the peak voltage of static electricity is greatly reduced, even if static electricity is generated on the upper substrate side and directly applied to the thin film transistor side without passing through the metal dot, the peak voltage is lowered, resulting in damage to internal circuits including the thin film transistor. has an effect that does not occur.

1 is an exemplary diagram for explaining a pixel and a driving circuit of a liquid crystal display device according to the present invention.
2 is a schematic diagram for explaining a liquid crystal display device according to an embodiment of the present invention.
3 is a front view for explaining a liquid crystal panel of a liquid crystal display device according to the present invention, and FIG. 4 is a cross-sectional view for explaining part II′ of FIG. 2 .
5 is an exemplary diagram for explaining an example of an electrostatic induction pattern according to the present invention.
6 is a schematic diagram for explaining the position of a discharge pattern as viewed from the lower side of the front cover according to the present invention.
7 is an exemplary view for explaining a liquid crystal display according to the present invention to which a multi-ground pattern is applied.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Like reference numbers throughout the specification indicate substantially the same elements. In the following description, if it is determined that a detailed description of a known technology or configuration related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, the component names used in the following description are selected in consideration of the ease of writing the specification, and may be different from the part names of the actual product.

When an element or layer is referred to as being “on” or “on” another element, it includes both a case where another element layer or another element is interposed therebetween as well as directly on another element layer. On the other hand, when an element or layer is referred to as "adjacent" to another element, it indicates that another element or layer is not intervened.

The size and thickness of each component shown in the drawings are shown for convenience of description, and the present invention is not necessarily limited to the size and thickness of the illustrated components.

1 is an exemplary diagram for explaining a pixel and a driving circuit of a liquid crystal display device according to the present invention.

A liquid crystal display device according to the present invention includes a liquid crystal panel 200 defined in an area where a plurality of gate lines GL and data lines DL intersect and including a plurality of pixels arranged in a matrix form, input from the outside. a timing controller 4 that aligns video signals and controls the operation timing of each pixel; gate lines GL and data provided in the liquid crystal panel 200 according to signals output from the timing controller 4; A gate driver 3 and a data driver 2 driving the line DL are included.

Each pixel includes a thin film transistor (TFT) and a liquid crystal capacitor (Clc) connected to the thin film transistor. The liquid crystal capacitor Clc is composed of a pixel electrode connected to the thin film transistor and a common electrode Vcom disposed with the pixel electrode and the liquid crystal interposed therebetween. The thin film transistor supplies an image signal from each data line DL to a pixel electrode in response to a scan pulse from each gate line GL.

The liquid crystal capacitor (Clc) charges the difference voltage between the image signal supplied to the pixel electrode and the common voltage (Vcom) applied to the common electrode, and adjusts the light transmittance by changing the arrangement of liquid crystal molecules according to the difference voltage. has a feature that implements

2 is a schematic diagram for explaining a liquid crystal display device according to an embodiment of the present invention.

In the liquid crystal display device according to an embodiment of the present invention, a lower substrate 210 and an upper substrate 220 are bonded to face each other by a sealant 400, and a liquid crystal panel 200 including a liquid crystal filled therebetween , the light source unit 100 for emitting light from the bottom of the liquid crystal panel 200 to the liquid crystal panel 200, the bottom cover 500 in which the liquid crystal panel 200 and the light source unit 100 are accommodated, A front case 600 located above the liquid crystal panel 200 and the light source unit 100 and fastened to the bottom cover 500 is included. In the front case 600, since the bottom surface A/A is formed transparently, light from the liquid crystal panel 200 is transmitted, and the edge portion of the display surface A/A is formed opaquely, thereby serving as a bezel. However, it is not necessarily limited thereto.

A discharge pattern 601 is provided on the inner surface of the front case 600 corresponding to the non-display area outside the liquid crystal panel 200 . The front case 600 may be formed of a transparent material such as glass at a position corresponding to the display area of the liquid crystal panel 200 to transmit an image displayed from the liquid crystal panel 200, but is not necessarily limited thereto. .

Specific structures of the liquid crystal panel 200 and the discharge pattern 601 will be described later.

3 is a front view for explaining the liquid crystal panel 200 of the liquid crystal display device according to the present invention, and FIG. 4 is a front cover 600 positioned above the part II' of FIG. 2 and the liquid crystal panel 200. It is a cross-sectional view to explain the structure.

Referring to FIGS. 3 and 4 , the liquid crystal panel 200 is defined by a display area A/A and a non-display area N/A. A ground pattern 281 is provided in a non-display area of the lower substrate 210 located outside the display area A/A. The ground pattern 281 may serve to supply a ground voltage to each pixel of the display area A/A by being connected to various wires of the display area A/A.

Referring to FIG. 4 , a conductive pattern 221 is provided on the upper side of the upper substrate 220 . The conductive pattern 221 is formed on the entire surface of the upper substrate 220 with a transparent conductive material (TCO) such as ITO, IZO, IGZO, or IGZO. The conductive pattern 221 is formed to penetrate the upper substrate 220 and is connected to the metal dot 223 connected to the ground pattern 281 of the lower substrate 210 . The metal dots 223 are formed of a metal material such as Ag, Cu, Al, Mg, Au, etc., and static electricity applied toward the top conductive pattern 221 of the upper substrate 220 is applied to the ground pattern 281 of the lower substrate 210. ) plays a role in discharging in the direction.

A thin film transistor, a pixel electrode 131 and a common electrode 132 are formed in the display area A/A of the lower substrate 100 .

In more detail, the lower substrate 210 includes a gate electrode 211, a gate insulating film 212 formed on the gate electrode 211, a semiconductor layer 213 positioned on the gate insulating film, An ohmic contact layer 214 provided on both sides of the semiconductor layer 213, an interlayer insulating film 215 formed to expose the ohmic contact layer 214, and an ohmic contact provided on both sides of the semiconductor layer 213 A source electrode 216 and a drain electrode 217 connected to one side of the layer 214, a pixel electrode 218 provided to extend from the drain electrode 217, and provided to cover the pixel electrode 218 and a common electrode 221 provided on the first lower passivation film 219 to be spaced apart from the pixel electrode 218.

A second lower passivation layer 229 may be further provided on the common electrode 221 .

On the upper substrate 220, a color filter 230 positioned to correspond to each pixel area, a black matrix 232 positioned between each pixel area, and a color filter 230 positioned to cover the black matrix 232 An upper passivation film 233 is provided.

Polarizers (not shown) may be further provided outside the lower substrate 210 and the upper substrate 220 .

The light source unit 100 is formed by providing a light source (not shown) including an LED or a cold cathode lamp, a light guide plate, and a plurality of optical sheets (not shown) inside the bottom cover 500 . The light source unit 100 induces light emitted from a light source (not shown) to emit surface light in the direction of the liquid crystal panel 200 through a light guide plate and an optical sheet.

As mentioned above, referring to FIG. 1 , a discharge pattern 601 is provided on the inner surface of the front case 600 . At this time, the discharge pattern 601 is positioned to face the non-display area N/A of the liquid crystal panel 200 and is formed to float apart from the upper substrate 220 . In addition, the front case 600 is formed of an insulating material such as plastic. When the front case 600 is made of a material such as plastic, the manufacturing cost is greatly reduced compared to when the front case 600 is made of metal, but since static electricity is not applied to the front case 600, the metal dots 223 of the upper substrate 220 ), static electricity is directly applied to the lower substrate 210, thereby causing defects such as thin film transistors. The discharge pattern 601 is to prevent this and is formed of a conductive material on the inner surface of the front case 600 .

In the liquid crystal display device according to the present invention, when static electricity is generated on the upper substrate 220 side, firstly, from the conductive pattern 221 located on the upper substrate 220 to the ground pattern 281 side via the metal dot 223 By being discharged, static electricity is prevented from being directly applied to the display area A/A on the lower substrate 210 side.

At this time, the conductive pattern 221 is formed of a transparent conductive material such as ITO having a thin thickness on the entire surface of the upper substrate 220. In this case, the conductive pattern 221 not only has high sheet resistance and capacitance, but also has static electricity. Since discharge is only directed to the dot 223, the discharge path is very narrow, and thus it takes a relatively long time for the applied static electricity to be discharged. When such static electricity exceeds a certain level, the discharge can directly damage devices such as thin film transistors of the lower substrate 210 through the shortest path, the lower substrate 210 .

To solve this problem, the discharge pattern 601 is formed on the inner surface of the front case 600 of the liquid crystal display according to the present invention. Therefore, even if the front case 600 is made of an insulating material, the static electricity generated from the upper substrate 220 is not directly applied to the lower substrate 210, and the voltage due to the static electricity is applied to the discharge pattern 601 of the front case 600. dissipation, and thus the peak voltage due to static electricity is lowered. When the peak voltage due to static electricity is lowered in this way, even if static electricity is applied toward the lower substrate 210, the peak voltage is lowered to a voltage level that does not damage elements such as thin film transistors. Damage to elements such as thin film transistors provided on the (210) side is prevented.

The discharge pattern 601 can be formed using various materials having high conductivity. For example, the discharge pattern 601 can be easily formed by attaching a conductive tape to the inner surface of the front case 600 corresponding to the periphery of the display surface A/A, but is not necessarily limited thereto.

The discharge pattern 601 may further include a static electricity induction pattern 602 protruding in a partial area to induce static electricity toward the discharge pattern 601 . Referring to FIG. 4 , the static electricity induction pattern 602 protrudes toward the upper substrate 220 to have a corner or a vertex, thereby performing a role similar to that of a lightning rod. Accordingly, the liquid crystal display device having the static electricity induction pattern 602 has a higher possibility that static electricity generated on the upper substrate 220 side is applied to the static electricity induction pattern 602, so that the thin film transistor on the lower substrate 210 side is circuits can be protected.

5 is an exemplary diagram for explaining another example of the static electricity induction pattern 602 . At this time, FIG. 5 shows a portion of the inner surface of the front case 600 . Referring to FIG. 5 , the static electricity induction pattern 602 is located on the inner surface of the front case 600 and may protrude in a sawtooth shape in the direction of the display surface A/A of the front case 600 . Likewise, the static electricity induction pattern 602 serves as a lightning rod to induce static electricity generated on the upper substrate 220 side to the static electricity induction pattern 602 side.

In order for the static electricity induction pattern 602 to protrude toward the upper substrate 220, the distance between the upper substrate 220 and the front case 600 may increase, but as shown in FIG. 6, the static electricity induction pattern 602 discharges When the pattern 601 protrudes in the lateral direction, the static electricity induction pattern 602 can be formed without increasing the distance between the upper substrate 220 and the front case 600 .

6 is a schematic diagram for explaining the position of the discharge pattern 601 when the front case 600 is viewed from the bottom. As shown in FIG. 5 , the discharge pattern 601 may be formed on the inner surface of the front case 602 to correspond to all outer edges of the display surface A/A, or may be formed on only a part of the outer edges.

If the discharge pattern 601 is formed to correspond to all outer edges of the display surface A/A, the discharge pattern 601 may be formed to surround the display surface A/A when viewed from the front. there is.

7 is an exemplary view for explaining a liquid crystal display according to the present invention to which a multi-ground pattern is applied.

The ground pattern of the liquid crystal display device may be applied in multiple structures. At this time, the multi-ground pattern is spaced apart from the first ground pattern 241 provided on the outer edge of the display surface A/A, and the first ground pattern 241 A second ground pattern 242 formed outside and at least one connection pattern 243 electrically connecting the first and second ground patterns 241 and 242 are included.

In such a multi-ground pattern, since static electricity generated in the upper substrate 220 corresponding to the display surface (A/A) is applied to the second ground pattern 242 via the first ground pattern 241, the movement path of static electricity increases. This minimizes the effects of static electricity.

In the liquid crystal display to which the multi-ground pattern is applied, static electricity generated from the upper substrate 220 does not pass through the metal dot 223, and the connection pattern 243 connecting the first and second ground patterns 241 and 242 is located. When directly applied to the area, the movement path of the static electricity is greatly reduced, so that the effect of static electricity may be increased.

In this case, in order to reduce the voltage peak of static electricity applied to the connection pattern 243, the discharge pattern 601 of the front case 600 in the liquid crystal display to which the multi-ground pattern is applied is the voltage peak of the connection pattern 243. It may be provided only at a position corresponding to the upper side. In this case, since the formation of the discharge pattern 601 is greatly reduced, in the case of forming the discharge pattern 601 using the conductive tape, the amount of the required conductive tape is greatly reduced, thereby reducing the process cost.

The liquid crystal display according to the present invention described above has an effect of reducing the peak voltage of static electricity by 5 kV or more according to experiments by forming the discharge pattern 601 on the inner surface of the front case 600. That is, according to the present invention, since the peak voltage of static electricity is greatly reduced, even if static electricity is generated on the upper substrate 220 side and directly applied to the thin film transistor side without passing through the metal dot 223, the peak voltage of the thin film transistor is lowered. It has the effect of not causing damage to internal circuits including.

The above description is only illustrative of the present invention, and various modifications may be made by those skilled in the art without departing from the technical spirit of the present invention. Therefore, the embodiments disclosed in the specification of the present invention are not intended to limit the present invention. The scope of the present invention should be construed by the claims below, and all techniques within the scope equivalent thereto should be construed as being included in the scope of the present invention.

200: liquid crystal panel 2: data driver
3: gate driver 4: timing controller
210: lower substrate 220: upper substrate
221: conductive pattern 281: ground pattern
223: metal dot 211: gate electrode
212: gate insulating film 213: semiconductor layer
214: ohmic contact layer 215: interlayer insulating film
216, 217: source and drain electrodes 219: first lower passivation film
218: pixel electrode 221: common electrode
Color filter 230 232: black matrix
233: upper passivation film 600: front case
601: discharge pattern 100: light source unit
500: bottom cover 602: static electricity induction pattern
241, 242: first and second ground patterns 243: connection pattern

Claims (11)

A liquid crystal panel including a plurality of pixels positioned in a matrix form in an area formed by crossing a plurality of gate lines and data lines of a display area;
A light source unit located on the rear surface of the liquid crystal panel;
A bottom cover accommodating the liquid crystal panel and the light source unit; and
A front case positioned on the liquid crystal panel to be fastened to the bottom cover and provided with a discharge pattern positioned to float on a surface opposite to the liquid crystal panel,
The front case is a liquid crystal display made of a plastic material. delete According to claim 1,
The discharge pattern is made of a conductive tape positioned so as to correspond to the edge of the display surface of the liquid crystal panel on the inner surface of the front case. According to claim 1,
The liquid crystal panel,
A lower substrate including a thin film transistor provided in the display area and a plurality of first and second electrodes generating a transverse electric field, an upper substrate including a color filter, and filling between the upper and lower substrates facing each other and bonding. Including a liquid crystal layer,
The lower substrate includes a ground pattern positioned at an edge of the display area,
The upper substrate includes a conductive pattern located on the upper front surface,
The conductive pattern and the ground pattern are electrically connected by a conductive dot pattern penetrating the upper substrate. According to claim 4,
The conductive pattern and the discharge pattern are positioned to be spaced apart from each other. According to claim 5,
The discharge pattern includes a static electricity induction pattern in which a partial region protrudes. According to claim 6,
The static electricity induction pattern has a shape protruding toward the upper substrate. According to claim 6,
The static electricity induction pattern protrudes toward the display surface of the front case. According to claim 4,
The ground pattern may include a first ground pattern provided outside the display surface of the display area;
a second ground pattern positioned outside the first ground pattern to be spaced apart from the first ground pattern; and
A liquid crystal display device comprising a connection pattern connecting the first and second ground patterns. According to claim 1,
The discharge pattern is located in an area corresponding to all edge parts outside the display area. According to claim 9,
The discharge pattern is located only in an area overlapping the connection pattern on the upper side of the connection pattern.

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