KR20070080996A - Liquid crystaldisplay device - Google Patents

Abstract

An LCD(Liquid Crystal Display) is provided to remove noise due to capacitance components and prevent ESD(Electro-Static Discharge) defect, by improving the structure of a bottom chassis to prevent the contact between a flexible circuit board and the bottom chassis. An LCD panel(120) displays an image. A backlight assembly(2000) is disposed below the LCD panel. A flexible circuit board(134) has conductive paths for applying signals to the LCD panel. The flexible circuit board is bent toward a rear surface of the backlight assembly. A bottom chassis(180) has a cutout portion corresponding to the bent flexible circuit board. The cutout portion of the bottom chassis is larger than the bent flexible circuit board.

Description

Liquid crystal display {LIQUID CRYSTALDISPLAY DEVICE}

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

FIG. 2 is a schematic perspective view of a portion of the liquid crystal display of FIG. 1.

3 is a schematic cross-sectional view taken along the line A-A of FIG.

4 is a rear view schematically illustrating the liquid crystal display of FIG. 1.

5 is an exploded perspective view of a liquid crystal display according to a second exemplary embodiment of the present invention.

6 is an exploded perspective view of a liquid crystal display according to a third exemplary embodiment of the present invention.

FIG. 7 is a schematic perspective view of a portion of the liquid crystal display of FIG. 6.

             <Description of the code | symbol about the principal part of drawings>

100: mold frame 110: top chassis

120: liquid crystal display panel 122: color filter substrate

124: TFT substrate 132: drive circuit

134: flexible circuit board 140: lamp unit

150: light guide plate 151: connection pad

160: reflector 180: bottom chassis

180a: incision 180b: engagement member

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device for removing noise from a circuit board and preventing ESD failure.

In general, a liquid crystal display (LCD) has advantages of small size, light weight, and large screen compared to a conventional display device, CRT (Cathode Ray Tube), and its development is being actively performed. In particular, the liquid crystal display device has been developed to perform a sufficient role as a flat panel display device, and is used not only as a liquid crystal for mobile phones, PDAs, digital cameras, camcorders, but also for monitors and large display devices of desktop computers. His range of use is expanding rapidly.

Such a liquid crystal display device includes a liquid crystal display panel for displaying a desired image on a screen by adjusting the amount of light transmitted according to an image signal applied to a plurality of control switches arranged in a matrix form, and a driving circuit for transmitting an external signal thereto. It includes a printed circuit board, a backlight assembly for irradiating light to the liquid crystal display panel, and a mold frame surrounding them.

In addition, the liquid crystal display device combines a liquid crystal display panel and a backlight assembly under the liquid crystal display panel, and fixes them with a top chassis and a bottom chassis.

In this case, the liquid crystal display panel and the external printed circuit board are electrically connected through a flexible printed circuit (FPC) to receive a signal. In general, the flexible circuit board connected to the liquid crystal display panel is bent at a predetermined angle and disposed on the bottom of the bottom chassis.

In a conventional flexible circuit board having bending characteristics, metal wiring is formed between two thin films. Therefore, in order to combine the liquid crystal display and the remaining parts, a setting component, for example, a steel fixture is pressed on the flexible circuit board according to the manufacturer. -Capacitance component is generated between the bottom chassis, thereby generating noise.

In addition, when the connection pad, which is a contact portion of the flexible circuit board, is in contact with the bottom chassis, electrostatic discharge (ESD) during the process may flow into the connection pad through the bottom chassis, thereby causing a defect.

Accordingly, an object of the present invention is to solve the above problems and to provide a liquid crystal display device capable of removing external noise and preventing ESD failure.

In order to achieve the above object, a liquid crystal display of the present invention includes a liquid crystal display panel displaying an image, a backlight assembly disposed below the liquid crystal display panel, and a conductive path for applying a signal to the liquid crystal display panel. The flexible circuit board bent to the back of the backlight assembly, and the bottom chassis formed with cutouts to correspond to the bent flexible circuit board.

In addition, the liquid crystal display includes a liquid crystal display panel for displaying an image, a backlight assembly disposed under the liquid crystal display panel, a conductive path and a driving circuit for applying a signal to the liquid crystal display panel, and a rear surface of the backlight assembly. The flexible printed circuit board may include a bent flexible circuit board, and a bottom chassis having a cutout formed to correspond to the bent flexible circuit board.

The cutout is formed to be larger than the size of the bent flexible circuit board, and the bent flexible circuit board is provided with a connection pad. The connection pad may further include a cutout portion in contact with the bottom chassis, and the cutout portion may be larger than the size of the connection pad.

Hereinafter, exemplary embodiments of the present invention will be described in more detail with reference to the drawings. However, the present invention is not limited to the embodiments disclosed below, but is embodied in various forms, and only the embodiments are intended to complete the disclosure of the present invention, and to those skilled in the art to fully understand the scope of the invention. It is provided to inform you. Like numbers refer to like elements in the figures.

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

Referring to the drawings, the liquid crystal display according to the present invention is a liquid crystal display panel 120 equipped with an edge type backlight and disposed on top of the liquid crystal display device of a chip on glass (COG) mounting method, and the liquid crystal display panel 120 ) A backlight assembly 2000 disposed below the mold, the mold frame 100 supporting the liquid crystal display panel 120 and the backlight assembly, the liquid crystal display panel 120, the backlight assembly 2000, and a mold frame It is composed of a top chassis 110 and a bottom chassis 180 surrounding the 100.

The liquid crystal display panel 120 includes a color filter substrate 122 and a thin film transistor substrate (TFT) substrate 124. At this time, the color filter substrate 122 is a substrate in which RGB pixels, which are color pixels in which a predetermined color is expressed while light passes, are formed by a thin film process. A common electrode made of a transparent conductor such as indium tin oxide (ITO) or indium zinc oxide (IZO) is formed on the front surface of the color filter substrate 122.

The TFT substrate 124 is a transparent glass substrate on which TFTs in matrix form are formed. The data line is connected to the source terminal of the TFTs, and the gate line is connected to the gate terminal. In addition, a pixel electrode made of a transparent electrode made of a transparent conductive material is formed in the drain terminal. When an electrical signal is input to the data line and the gate line, each TFT is turned on or turned off to apply an electrical signal necessary for pixel formation of the drain terminal. When the TFT is turned on by applying power to the gate terminal and the source terminal of the TFT substrate 124, an electric field is formed between the pixel electrode and the common electrode of the color filter substrate 122, thereby forming the TFT substrate 124 and the color. The arrangement of the liquid crystals injected between the filter substrates 122 is changed, and the light transmittance is changed according to the changed arrangement to obtain a desired image. At one edge of the TFT substrate 124, a plurality of pads and circuit patterns to be connected to an external circuit are formed. That is, a driving IC (integrated circuit) 132 for transmitting an image signal and a gate signal is respectively provided on the data line and the gate line, and the driving IC 132 or the data line and the gate line for electrical connection with an external driving circuit unit. And a plurality of metal pads extending at and partially exposed at their ends.

One end of the flexible printed circuit board 134 is connected to one side of the TFT substrate 124, and a connection pad 151 for connecting to an external printed circuit board (not shown) is formed at the other end.

In the drawing, the flexible circuit board 134 is formed on one side of the liquid crystal display panel 120 to simultaneously transmit the image signal and the gate driving signal. However, the present invention is not limited thereto, and the external image signal and the gate driving signal may be applied separately. For this purpose, the data and gate sides may be separately formed.

The backlight assembly 2000 includes a lamp unit 140, a light guide plate 150 coupled to the lamp unit 140, a reflector plate 160 disposed below the light guide plate 150, and a plurality of light guide plates 150. Optical sheet 170.

The lamp unit 140 is composed of a lamp 142 and a lamp clamp 144. As the lamp 142, it is effective to use a cold cathode ray tube type lamp. In addition, the shape of the lamp 142 may be an I-shape as shown, and is not limited thereto, and may have various shapes such as an N-shape, an M-shape, and a meandering shape. The lamp clamp 144 maximizes the light utilization efficiency by reflecting light emitted radially from the cold cathode ray tube type lamp in one direction.

The light guide plate 150 is coupled to the lamp clamp 144 to change light having an optical distribution in the form of a line light source generated by the lamp unit 140 to light having an optical distribution in the form of a surface light source. As the light guide plate 150, a wedge type plate or a parallel flat plate may be used.

As the reflecting plate 160, a plate having a high light reflectance is used. Although the reflective plate 160 is illustrated as having a flat shape in the drawing, the reflective plate 160 may be manufactured in a curved shape having a reference reflective surface and a triangular protrusion protruding from the reference reflective surface.

The optical sheet 170 is composed of a diffusion sheet and at least one prism sheet, and is disposed on the light guide plate 140 to uniform the luminance distribution of the light emitted from the light guide plate 140.

The liquid crystal display panel 120 and the backlight assembly 2000 are fixedly supported by the mold frame 100, and received and protected by the top chassis 110 and the bottom chassis 180.

That is, in the mold frame 100, an accommodating space is formed to sequentially receive the reflecting plate 160, the light guide plate 150, and the optical sheet 170, and the liquid crystal display panel 120 is formed on the optical sheet 170. Partly overlapped with the mold frame 100 is placed.

The top chassis 110 is formed in a rectangular frame having a flat portion and a sidewall portion that are bent at right angles to prevent the liquid crystal display panel 120 from being separated and to protect the liquid crystal display panel 120 which is easily broken by an impact applied from the outside. The bottom chassis 180 is formed in a rectangular plate shape, and a coupling member 180b is formed at one side and the other side opposite to the top chassis 110, respectively. In this case, the bottom chassis 180 may have a form including sidewalls.

The bottom chassis 180 has a corresponding region removed so that the bent flexible circuit board 134 and the connection pad 151 do not contact each other.

The structure between the bottom chassis and the overlapping region of the flexible circuit board will be described in detail with reference to the following drawings.

FIG. 2 is a perspective view schematically illustrating a portion of the liquid crystal display of FIG. 1, FIG. 3 is a schematic cross-sectional view illustrating a line A-A of FIG. 1, and FIG. 4 is a rear view schematically illustrating the liquid crystal display of FIG. 1.

2 and 3 illustrate a thick thickness of the flexible circuit board for convenience of description, and in particular, in FIG. 2, the connection pad is bent by 90 degrees in the direction of the arrow, but is illustrated before being bent for convenience.

Referring to the drawings, the flexible circuit board 134 includes a base film that is flexible and easily bent, and a plurality of metal wires that are electrically patterned with a conductive material on the base film to transmit electrical signals. The metal wire includes a plurality of ground wires and a plurality of input / output wires for inputting and outputting a predetermined signal. The input / output wiring includes a data wiring for transmitting a data signal, a clock wiring for transmitting a clock signal, and a voltage wiring for transmitting a power supply voltage. The apparatus may further include a dummy wiring to which a signal is not input.

One end of the flexible circuit board 134 is connected to the liquid crystal display panel 120, and a connection pad 151 is formed at the other end of the flexible circuit board 134 and positioned on the bottom of the bottom chassis 180.

That is, the flexible circuit board 134 is installed to surround one end of the mold frame 100 and a part of the bottom chassis 180, and the flexible circuit board 134 bent to the bottom of the bottom chassis 180 is formed. The connection pad 151 is in contact with the external printed circuit board.

A cutout 180a is formed in the bottom chassis 180 in an area corresponding to the area of the bent flexible circuit board 134. That is, cutouts 180a corresponding to the sizes of the flexible circuit board 134 and the connection pad 151 that are bent to the bottom of the bottom chassis 180 are formed. The shape of the cutout 180a is not limited, and the cutout 180a is preferably formed to have a sufficient size corresponding to the shape of the flexible circuit board 134 and the connection pad 151.

As such, a separate insulating layer is formed between the bottom chassis 180 and the flexible circuit board 134 by forming the cutout 180a such that the flexible circuit board 134 and the connection pad 151 do not contact the bottom chassis 180. The noise due to the capacitance can be removed without forming the connection, and the connection pad 151 can also prevent the inflow of the ESD.

In the above-described embodiment, the liquid crystal display device having the edge type backlight assembly is illustrated, but the connection method of the present invention is not limited thereto and may be applied to liquid crystal display devices having various shapes. For example, the configuration of the lamp of the liquid crystal display panel may be formed in a direct type. In the following, an example of such a possibility will be described with reference to the drawings. In this case, description overlapping with the above-described embodiment will be omitted.

5 is an exploded perspective view of a liquid crystal display according to a second exemplary embodiment of the present invention. Since the light source of the backlight assembly is a direct type, it is the same as that of the first embodiment, and therefore, the structure of the backlight assembly, the flexible circuit board, and the bottom chassis will be described.

Referring to the drawings, the backlight assembly 2000 according to the present exemplary embodiment includes a lamp unit 140 that generates light, a reflector 160 disposed under the lamp unit 140, and an upper portion of the lamp unit 140. The optical sheet 170 is disposed, and includes a reflecting plate 160, a lamp unit 140, and a mold frame 100 for accommodating the optical sheet 170.

The lamp unit 140 includes a plurality of bar lamps 190 arranged in parallel, a plurality of lamp fixing units 192 for fixing the lamps, and a lamp support unit 194 in which the plurality of lamp fixing units 192 are accommodated. ). The plurality of lamps 190 mainly use cold cathode fluorescent lamps, and each lamp 190 includes a glass tube, inert gases included in the glass tube, and a negative electrode and a positive electrode installed at both ends of the glass tube. Each of the lamp fixing portions 192 includes a base substrate on which one end of the lamp 190 is seated, and a fixing clip and a fixing protrusion for protruding from the base substrate to fix the lamp. The lamp support 194 includes a bottom surface on which the plurality of lamp fixing portions 192 are mounted and a sidewall extending vertically from the bottom surface. In this case, the lamp fixing part 192 may be formed of a conductive material to apply power to the electrode of the lamp 190. In this case, the lamp support 194 may be formed of an insulating material to electrically insulate the electrode of the lamp 190 from the mold frame 100.

The reflector plate 160 includes a reflective bottom surface on which the lamp 190 is located, and first and second reflective inclined surfaces having a predetermined inclination from the reflective bottom surface at edges corresponding to opposite sides of the lamp unit 140. Include. The reflective plate 160 may be attached to the mold frame 100 by an adhesive, a double-sided adhesive tape, or the like, and may be fastened to the mold frame 100 using a screw.

The optical sheet 170 includes a diffuser plate and a plurality of prism sheets, and the diffuser plate directs the light incident from the plurality of lamps toward the front of the liquid crystal display panel 120 and has a uniform distribution in a wide range. Diffuse the light to irradiate the liquid crystal display panel 120, and the prism sheet serves to change the light incident to the prism sheet to be vertically emitted.

The mold frame 100 is formed in a box shape of a rectangular parallelepiped with an upper surface open to form a storage space having a predetermined depth therein. That is, the mold frame 100 includes a bottom surface and first to fourth sidewalls that protrude vertically at each edge from the bottom surface. Further, the first and third side walls facing each other located on opposite sides of the outermost lamp are further formed with first and second inclined surfaces inclined at an angle therefrom and extending toward the bottom surface. In addition, a stepped stepped surface is formed at an upper end between the first and third sidewalls and the first and second inclined surfaces. As a result, the bottom surface and the inclined surface of the reflective plate 160 are positioned on the bottom surface and the inclined surface of the mold frame 100, and the optical sheet 170 is seated on the stepped stepped surface.

The flexible circuit board 134 is installed to surround the side of the mold frame 100 and the bottom of the bottom chassis 180 from the TFT substrate 124, and the mold frame 100 faces the top chassis 110 facing each other. The bottom chassis 180 is fixedly coupled by the coupling member 180b formed in the bottom chassis 180. The bottom chassis 180 has a cutout 180a formed in a region corresponding to the bottom chassis 180 so as not to contact the flexible circuit board 134 and the connection pad 151. The cutout 180a may be formed to a sufficient size to correspond to the shape of the flexible circuit board 134 and the connection pad 151.

Accordingly, a liquid crystal display is manufactured by assembling the top chassis 110, the liquid crystal display panel 120, the backlight assembly 2000, the mold frame 100, and the bottom chassis 180 having the cutout 180a formed therein.

In the above embodiments, the liquid crystal display of the chip on glass (COG) mounting method is illustrated, but the present invention is not limited thereto and may be applied to the liquid crystal display of the tape-automated bonding (TAB) mounting method. In the following, such an example will be described with reference to the drawings. In this case, description overlapping with the above-described embodiments will be omitted.

6 is an exploded perspective view of a liquid crystal display according to a third exemplary embodiment of the present invention, and FIG. 7 is a perspective view schematically illustrating a part of the liquid crystal display of FIG. 6.

6 and 7, the liquid crystal display according to the present exemplary embodiment includes a liquid crystal display panel 120 having an edge type backlight and a tab-automated bonding (TAB) mounting method. It includes a backlight assembly 2000 disposed below.

The liquid crystal display panel 120 includes a color filter substrate 122 and a TFT substrate 124, and a flexible circuit board 134 is connected to the TFT substrate 124.

That is, one end of the flexible circuit board 134 is connected to the TFT substrate 124, and the other end is connected to the external printed circuit board (not shown) by the connection pad 151 is formed to apply a signal Receive.

In this case, unlike the first and second embodiments, the flexible circuit board 134 is equipped with a tab (TAB) IC 132 and includes RGB (Read, Green) generated from an external printed circuit board (not shown). , Blue) signal, shift start clock (SSC) signal, latch pulse (LP) signal, gamma analog ground signal, digital ground signal, digital power supply, analog power supply common voltage, accumulated voltage, etc. are transmitted to the liquid crystal display panel 120. .

Here, the flexible circuit board 134 is installed to surround the side of the mold frame 100 and the bottom of the bottom chassis 180 from the TFT substrate 124, and is bent on the bottom of the bottom chassis 180. 134 and a connection pad 151 are disposed.

The top chassis 110 and the bottom chassis 180 are fixedly coupled to the mold frame 100, and the bottom chassis 180 corresponds to the bent flexible circuit board 134 and the connection pad 151 so that the bottom chassis 180 is not in contact. An incision 180a is formed in the region.

Accordingly, the liquid crystal display according to the present invention can prevent distortion of a signal due to capacitance components between the steel fixture, the flexible circuit board, and the bottom chassis during the setting process, and the connection pad 151 connected to the flexible circuit board 134 may be prevented. By preventing the bottom chassis 180 from contacting, it is possible to prevent an ESD failure during the process.

Although described above with reference to the drawings and embodiments, those skilled in the art that the present invention can be variously modified and changed within the scope without departing from the spirit of the invention described in the claims below. I can understand.

As described above, the liquid crystal display according to the present invention changes the structure of the bottom chassis to prevent contact of the flexible circuit board and the bottom chassis. Therefore, it is possible to remove noise caused by capacitance components and to prevent ESD failure.

Claims (10)

A liquid crystal display panel displaying an image, A backlight assembly disposed under the liquid crystal display panel; A flexible circuit board having a conductive path for applying a signal to the liquid crystal display panel and being bent to the rear surface of the backlight assembly; And a bottom chassis having a cutout portion formed to correspond to the bent flexible circuit board. The liquid crystal display device of claim 1, wherein the cutout portion is formed to be larger than a size of the bent flexible circuit board. The liquid crystal display device of claim 1, wherein the bent flexible circuit board is provided with a connection pad. The liquid crystal display of claim 3, wherein an incision is formed such that the connection pad does not contact the bottom chassis. The liquid crystal display device of claim 4, wherein the cutout portion is formed to be larger than a size of the connection pad. A liquid crystal display panel displaying an image, A backlight assembly disposed under the liquid crystal display panel; A flexible circuit board having a conductive path and a driving circuit for applying a signal to the liquid crystal display panel and bent to the rear surface of the backlight assembly; And a bottom chassis having a cutout portion formed to correspond to the bent flexible circuit board. The liquid crystal display device of claim 6, wherein the cutout portion is formed to be larger than a size of the bent flexible circuit board. The liquid crystal display of claim 6, wherein the bent flexible circuit board is provided with a connection pad. The liquid crystal display of claim 8, wherein an incision is formed such that the connection pad does not contact the bottom chassis. The liquid crystal display of claim 9, wherein the cutout portion is formed to be larger than a size of the connection pad.

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