KR20080038591A - Liquid crystal display device - Google Patents

Abstract

An LCD device is provided to form a contact pad on a control board and form a contact bar on a shield case, and ground the contact bar, thereby preventing interference caused by an electromagnetic wave deserted from the control board. An LCD(Liquid Crystal Display) panel(100) displays an image. A backlight unit(200) supplies light to the LCD panel. A bottom chassis(350) contains the LCD panel and the backlight unit. A shield case(500) is joined to the rear side of the bottom chassis. A driving circuit unit(400) includes a data PCB(Printed Circuit Board)(410) and a control board(450), and the data PCB is connected to the LCD panel to drive the LCD panel. At least one connector(451-453) is formed on the control board. A contact pad(457) is formed between the connectors to contact the shield case.

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY DEVICE}

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

FIG. 2 is a plan view illustrating in detail the control board of the liquid crystal display shown in FIG. 1.

3 is a perspective view illustrating a first embodiment of a shield case of the liquid crystal display shown in FIG. 1.

FIG. 4 is a perspective view illustrating a second embodiment of the shield case of the liquid crystal display shown in FIG. 1.

5 is a perspective view illustrating in detail the shield case coupled to the bottom chassis illustrated in FIG. 1.

<Description of the symbols for the main parts of the drawings>

100: liquid crystal panel 110: color filter substrate

120: thin film transistor substrate 200: backlight unit

210: lamp 220: reflective sheet

230: diffusion sheet 240: prism sheet

250: protective sheet 300: mold frame

310: panel mounting portion 320: data PCB storage portion

350: bottom chassis 351,455,521: through hole

400: driving circuit 410: data PCB

420: data TCP 430: data driving circuit

440: first signal transmission film 450: control board

451,452,453: First to third connectors 454: Second signal transmission film

457: ground pad 460: timing controller

470: memory 480: power supply

500: shield case 505: opening

510: ground bar 513: contact portion

515: hole 522: coupling member

600: metal plate 700: top chassis

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device which prevents electromagnetic interference induced by a control board.

In liquid crystal displays, two substrates on which field generating electrodes are formed are disposed so that the surfaces on which the two electrodes are formed face each other, liquid crystal is injected between the two substrates, and a voltage is generated by applying a voltage to the two electrodes. By moving the liquid crystal molecules, the device expresses an image by the amount of light transmitted that varies accordingly. To this end, the liquid crystal display includes a liquid crystal panel in which liquid crystal cells are arranged in a matrix, a backlight unit for providing light to the liquid crystal panel, and a driving circuit unit for generating various signals necessary for the liquid crystal panel to implement an image.

The driving circuit unit is a printed circuit board (PCB) connected to a liquid crystal panel by a tape carrier package (hereinafter referred to as 'TCP'), and a flexible printed circuit board (PCB). A control board connected to the printed circuit board is referred to as 'FPCB'. And a gate driver and a data driver formed on the TCP and the PCB, a timing controller formed on the control board to control the gate and the data driver, a memory for storing signals of the timing controller, and a power supply.

Here, the timing controller and the memory are constantly transmitted through a plurality of signal wires. In addition, the signal is always transmitted from the connector connecting the gate and data driver and the control board. At this time, electromagnetic waves are induced between the plurality of signal wires, which causes a problem of distorting the signal by interfering with a signal supplied from the liquid crystal panel.

Accordingly, an object of the present invention is to provide a liquid crystal display device using a ground pad to strengthen the ground between the shield case, the bottom chassis and the control board, and to prevent the interference of electromagnetic waves induced in the control board.

In order to achieve the above technical problem, the present invention provides a liquid crystal panel for displaying an image, a backlight unit for supplying light to the liquid crystal panel, a bottom chassis for accommodating the liquid crystal panel and the backlight unit, and a shield coupled to a rear surface of the bottom chassis. A driving circuit unit including a case and a data printed circuit board connected to the liquid crystal panel for driving the liquid crystal panel, and a control board having at least one connector formed thereon and a ground pad formed between the connectors to contact the shield case. It provides a liquid crystal display device comprising a.

Here, the shield case is formed with a ground bar in contact with the ground pad.

At this time, the ground bar is formed with a contact portion protruding to one side.

In addition, the ground bar is formed with a hole on one side.

The conductive plate further includes a conductive plate between the bottom chassis and the shield case.

In this case, the conductive plate further includes a conductive gasket in contact with the shield case.

In order to achieve the above technical problem, the present invention is coupled to a liquid crystal panel for displaying an image, a backlight unit for supplying light to the liquid crystal panel, a bottom chassis for accommodating the liquid crystal panel and the backlight unit, and a rear surface of the bottom chassis. A shield case including a ground bar formed with a contact portion or a hole protruding toward one side, a conductive plate formed between the bottom chassis and the shield case to contact the shield case with a conductive gasket, and the liquid crystal panel to drive the liquid crystal panel; According to an aspect of the present invention, there is provided a liquid crystal display including a data printed circuit board connected to a control circuit and a control board including at least one connector formed thereon and a control board having a ground pad formed therebetween to contact the ground bar.

Other objects and features of the present invention in addition to the above object will become apparent from the description with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 1 to 5.

1 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 2 is a plan view showing in detail a control board of the liquid crystal display shown in FIG. 1.

1 and 2, the liquid crystal display according to the present invention includes a liquid crystal panel 100 for displaying an image, a driving circuit unit 400 for driving the liquid crystal panel 100, and a liquid crystal panel 100. A backlight unit 200 for supplying light, a bottom chassis 350 accommodating the liquid crystal panel 100 and the backlight unit 200, and a shield case 500 coupled to the bottom of the bottom chassis 350 are provided.

Specifically, the liquid crystal panel 100 is formed by bonding the color filter substrate 110 and the thin film transistor substrate 120 with the liquid crystal interposed therebetween. The liquid crystal panel 100 includes liquid crystal cells Clc independently driven by the thin film transistor TFT in regions defined by intersections of the gate lines GL and the data lines DL. The thin film transistor TFT supplies a pixel signal from the data line DL to the liquid crystal cell Clc in response to a scan signal from the gate line GL.

The driving circuit unit 400 includes a gate driver and a data driver for driving the gate line GL and the data line DL formed on the thin film transistor substrate 120 of the liquid crystal panel 100. Here, the gate driver is implemented using an amorphous silicon (a-Si) type thin film transistor or a polysilicon (p-Si) type thin film transistor on the thin film transistor substrate 120. The gate driver sequentially supplies a scan signal of a gate-on voltage to the gate lines GL. In addition, the gate driver supplies the gate-off voltage to the gate lines GL in a period other than the period in which the gate-on voltage is supplied.

The data driver is electrically connected to the data PCB 410 through the data TCP 420 on which the data driver circuit 430 is mounted. The data driving circuit 430 converts the pixel data into an analog pixel signal and supplies the pixel data to the data lines DL. The data PCB 410 may supply control signals, power signals, and pixel data from the timing controller 460 and the power supply unit 480 to the corresponding driving circuit. In the case of a large LCD, the timing controller 460 and the power supply unit 480 may be mounted on a separate board, that is, the control board 450, and connected to the data PCB 410. In this case, the data PCB 410 is connected to the data TCP 420 and the control board 450 through the first signal transmission film 440. Accordingly, the data PCB 410 supplies control signals, power signals, pixel data, and the like from the timing controller 460, the power supply unit 480, and the like, which are mounted on the control board 450 to be described later, to the corresponding driving circuit.

The backlight unit 200 supplies light to the liquid crystal panel 100. The backlight unit 200 includes a light source for supplying light, a reflection sheet 220 for reflecting light supplied to a plurality of light sources below to the upper liquid crystal panel 100, and a diffusion for uniforming the luminance of the light supplied from the light source. Optical films such as a sheet 230 and a prism sheet 240 for increasing the efficiency of light diffused and supplied from the diffusion sheet 230 are further provided.

The light source may use a plurality of lamps 210, a light emitting diode, or a surface light source. The light source includes a plurality of lamps 210 formed in parallel, and lamp holders for supplying power to the lamp 210 and supporting and fixing the lamp 210 are formed at both sides of the plurality of lamps 210. Since a plurality of lamps 210 are formed, a bright line and a dark line are formed between the lamps 210, and a diffusion sheet 230 is formed on the upper part of the lamp 210 to prevent this.

The diffusion sheet 230 diffuses the light supplied from the plurality of lamps to remove the bright and dark lines. At this time, the diffused light is low in efficiency, the luminance of the light supplied to the liquid crystal panel 100 is low. Therefore, the prism sheet 240 is formed on the diffusion sheet 230 in order to increase the luminance. Then, a protective sheet 250 for protecting the optical sheets such as the prism sheet 240 is further formed.

The backlight unit 200 is not limited to a direct type for supplying light directly from the lower front surface of the liquid crystal panel 100 as in the present invention, but an edge type for supplying light from the side of the liquid crystal panel 100 may be applied. have.

The bottom chassis 350 includes a backlight housing in which the backlight unit 200 is accommodated and fixed. The bottom chassis 350 is made of a material such as metal to protect the backlight unit 200 and the liquid crystal panel 100 mounted on the backlight unit 200. The backlight unit 200 is accommodated in the bottom chassis and fixed.

When the reflective sheet 220, the light source, and the optical sheets are sequentially received in the housing of the bottom chassis 350, the mold frame 300 is fixed along the outer wall of the bottom chassis 350. The mold frame 300 has a panel seating portion 310 to which the liquid crystal panel 100 is seated and fixed. A data PCB accommodating part 320 for fixing the data PCB 410 is further formed on one side thereof. When the liquid crystal panel 100 is seated and fixed to the panel seating part 310 of the mold frame 300, the data PCB 410 connected to one side of the liquid crystal panel 100 by the data TCP 420 may be a data PCB accommodating part ( 320 is stored. The control board 450 connected to the data PCB 410 and the first signal transmission film 440 is coupled to the bottom of the bottom chassis 350 through the through holes 351 and 455 and the coupling member 522.

The control board 450 is formed by sequentially stacking a signal transmission layer on which a metal thin film is patterned on a base, and a protective film for protecting the signal transmission layer, and a plurality of PCBs formed by such a structure. do. As shown in FIG. 2, the control board 450 includes a timing controller 460, a memory 470, a power supply unit 480, and the like mounted on one surface thereof.

Here, the power supply unit 480 mounted on the control board 450 generates a voltage signal such as a gate on voltage, a gate off voltage, and an analog driving voltage AVDD supplied to the data driving circuit 430. Thus, the gate driving circuit and the data driving circuit 430 are respectively supplied. The timing controller 460 generates a control signal such as a start pulse, a shift clock, and an output control signal, supplies the control signal to each of the gate driving circuit and the data driving circuit 430, and supplies an image signal supplied from the outside to the data driving circuit 430. To feed. The memory 470 stores the previous frame data signal supplied from the timing controller 460 and supplies the same to the timing controller 460 when the current frame data is supplied to the timing controller 460. In addition, the control board 450 may include a first connector 451 and a second which are fastened to the first signal transmission film that supplies the control signal, the power signal, and the pixel data generated by the control board 450 to the data PCB 410. A connector 452 and a third connector 453 engaged with the second signal transmission film 454 for supplying an image signal from the outside is provided.

The control board 450 supplies the pixel data and the power signal supplied from the outside through the second signal transmission film 454 connected to the third connector 453. Generates a power signal and a control signal supplied to the driving ICs from the timing controller 460 and the power supply unit 480 mounted on the control board 450 through the supplied pixel data and the power signal, and generates the generated drive signal and control signal. And supply the pixel data to the data PCB 410 through the first signal transmission film 440. In this case, the first signal transmission film 440 is attached to the rear surface of the data PCB 410 and is inserted into the first and second connectors 451 and 452 installed on the control board 450. In addition, the second signal transmission film 454 is connected to an external power supply device and a graphic controller, and is inserted into a third connector installed in the control board 450. The first and second signal transmission films 440 and 454 use signal transmission lines and connection pads formed of metal thin films connected to each other on a base film, and FPCBs formed by sequentially stacking protective films.

Here, much interference due to electromagnetic waves is generated between the timing controller 460 and the memory 470 and between the first connector 451 and the second connector 452. In order to prevent the interference of electromagnetic waves, the control board 450 according to the present invention includes a ground pad 457.

The ground pad 457 is formed of a conductive material on the board. The ground pad 457 effectively grounds electromagnetic waves induced by signals supplied to the liquid crystal panel 100 through the first and second connectors 451 and 452 and signals transmitted between the timing controller 460 and the memory 470. 2 is formed between the first and second connectors 451 and 452, as shown in FIG. The ground pad 457 also grounds electromagnetic waves induced by the gamma voltage generator. The ground pad 457 further contacts the bottom chassis 350 and the shield case 500 formed of a conductive material, thereby improving the grounding effect.

In this case, the ground pad 457 may have a hole through the board in the center of the pad. In addition, the ground pad 457 may be connected to the bottom chassis 350 using a conductive coupling member in the hole.

In addition, a shield case 500 is formed on an upper surface of the control board 450 to protect the control board 450.

Hereinafter, the structure of the shield case 500 will be described in detail with reference to FIGS. 3 and 4. The structure of the shield case 500 shown in FIG. 3 and FIG. 4 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the structure of the shield case 500 may be modified in other forms.

3 is a perspective view illustrating a first embodiment of a shield case of the liquid crystal display shown in FIG. 1.

The shield case 500 physically and electrically protects electronic devices such as the timing controller 460, the memory 470, and the power supply unit 480 formed on the control board 450. To this end, the shield case 500 is formed of a metal material. The shield case 500 is coupled to the bottom chassis 350 by using the through holes 521 and the coupling member 522 formed at both sides.

An opening 505 is formed at one side of the shield case 500. First and second connectors 451 and 452 for connecting the first signal transmission film 440 and the control board 450 are exposed through the opening 505. The first signal transmission film 440 is easily fastened to the control board 450 by the shield case 500. In addition, the first signal transmission film 440 may be fastened and fixed to the control board 450 while aligning accurately. Here, the opening 505 may be selectively formed according to the number of the first signal transmission films 440.

In addition, an opening is formed on the other side of the shield case 500 to fasten the second signal transmission film 454 and the third connector 453.

The shield case 500 includes a ground bar 510 in contact with the ground pad 457 formed on the control board 450. The ground bar 510 is integrally formed between the openings 505 formed on one side of the shield case 500. In particular, the ground bar 510 is formed along the surface of the protruding region between the two openings 505.

Here, the ground bar 510 is in contact with the ground pad 457 formed on the control board 450 through the contact portion 513. In addition, the ground bar 510 grounds the electromagnetic waves induced in the control board 450 through the ground pad 457. In particular, the ground bar 510 is integrally formed with the shield case 500 to connect the ground pad 457 and the shield case 500, and improves the grounding effect by grounding electromagnetic waves through the shield case 500.

FIG. 4 is a perspective view illustrating a second embodiment of the shield case of the liquid crystal display shown in FIG. 1.

4 has the same components except for the hole 515 formed in the ground bar 510, in contrast to the shield case shown in FIG. 3, and thus, detailed descriptions of the same components will be omitted.

The shield case 500 includes a ground bar 510 having a hole 515 formed in contact with the ground pad 457.

The ground bar 510 is formed along the surface of the protruding region between the two openings 505, and a hole 515 having a predetermined size is formed at one side thereof. The ground bar 510 is in contact with the ground pad 457 of the control board 450 using a conductive contact member in the hole 515. In addition, the ground bar 510 is coupled to the ground pad 457 in which the hole is formed using a conductive coupling member. For example, the ground bar 510 contacts the ground pad 457 by inserting a metal pin into the hole 515 or is coupled to the ground pad 457 using a metal screw. The ground bar 510 may be electrically connected to the bottom chassis 350 where the through hole is formed after being coupled with the ground pad 457 through the coupling member. The ground bar 510 is connected to the shield case 500 and the bottom chassis 350 to greatly improve the grounding effect.

5 is a perspective view illustrating in detail the shield case coupled to the bottom chassis illustrated in FIG. 1.

Referring to FIG. 5, the bottom chassis 350 is coupled to a control board 450 having first and second connectors 451 and 452 formed on a rear surface thereof, and a shield case 500 for protecting the control board 450. In this case, the bottom chassis 350 has a groove formed between the shield case 500 and the bottom chassis 350. The bottom chassis 350 and the shield case 500 are contacted using the metal plate 600 to improve the grounding effect.

The metal plate 600 is formed to match the height of the groove formed in the bottom chassis 350 and the width of the shield case. The metal plate 600 is supported by the shield case 500 coupled to the bottom chassis 350. Here, the shield case 500 is coupled to the bottom chassis 350 by using the coupling member in the through hole 515.

In addition, the metal plate 600 may contact the shield case 500 using a conductive gasket when the contact with the shield case 500 is poor. The metal plate 600 contacts the shield case 500 by disposing a plurality of conductive gaskets on an upper surface thereof.

The metal plate 600 reinforces the electrical connection between the bottom chassis 350 and the shield case 500 in order to improve the effect of grounding the electromagnetic waves induced in the control board 450.

The liquid crystal display further includes a top chassis 700 coupled with the bottom chassis 350. The top chassis 700 is formed of a metal material, and is electrically connected to the bottom chassis 350 to further improve the grounding effect.

As described above, the liquid crystal display according to the present invention prevents interference of electromagnetic waves induced in the control board by forming a ground pad on the control board and grounding the ground bar on the shield case. The liquid crystal display may increase the grounding effect by changing the shape of the shield case. The liquid crystal display device can prevent display quality problems by preventing distortion of the panel driving signal due to interference of electromagnetic waves.

Although the detailed description of the present invention described above has been described with reference to a preferred embodiment of the present invention, those skilled in the art or those skilled in the art, those skilled in the art, described in the claims below It will be understood that various modifications and changes can be made in the present invention without departing from the spirit and scope of the invention.

Claims (7)

A liquid crystal panel for displaying an image; A backlight unit supplying light to the liquid crystal panel; A bottom chassis accommodating the liquid crystal panel and the backlight unit; A shield case coupled to the bottom of the bottom chassis; A driving circuit unit including a data printed circuit board connected to the liquid crystal panel to drive the liquid crystal panel, and a control board having at least one connector formed thereon and a ground pad formed between the connectors to contact the shield case. Liquid crystal display characterized in that. According to claim 1, And the shield case has a ground bar in contact with the ground pad. The method of claim 2, The ground bar is a liquid crystal display, characterized in that the contact portion protruding to one side is formed. The method of claim 2, And a hole formed at one side of the ground bar. According to claim 1, And a conductive plate between the bottom chassis and the shield case. The method of claim 5, The conductive plate further comprises a conductive gasket in contact with the shield case. A liquid crystal panel for displaying an image; A backlight unit supplying light to the liquid crystal panel; A bottom chassis accommodating the liquid crystal panel and the backlight unit; A shield case coupled to a rear surface of the bottom chassis and including a ground bar formed with a contact portion or a hole protruding to one side; A conductive plate formed between the bottom chassis and the shield case and contacting the shield case with a conductive gasket; And a driving circuit unit including a data printed circuit board connected to the liquid crystal panel to drive the liquid crystal panel, and a control board having at least one connector formed thereon and a ground pad formed between the connectors to contact the ground bar. Liquid crystal display device characterized in that.

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