KR20110028969A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: A liquid display device is provide to improve screen display picture quality and minimize the amount of power waste due to heat among power supplied to an LED according to effectively release heat to external side of a lower cover as heat generated from anode unit of an LED array is transmitted to a lower cover. CONSTITUTION: A liquid display device includes a liquid panel and an LED(102) array which supplies the light to a liquid panel by being arranged to at least one side of the liquid panel. A printed circuit board(103) which an LED array is mounted is included. A first released heat(104) has a heat conductivity by being attached to an anode unit(105) of an LED array which is mounted on a printed circuit board. The printed circuit board is accepted to correspond to an inner surface. A lower cover(106), which one part of an inner bottom surface is adhered to the first released heat, is included.

Description

[0001] LIQUID CRYSTAL DISPLAY DEVICE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and in particular, a structure in which heat generated from a light emitting diode provided as a light source can be quickly released to the outside of the lower cover, thereby minimizing the amount of waste generated by heat generation during power supply and emitting light by heat. The present invention relates to a liquid crystal display device having improved display quality by minimizing the change in characteristics of the diode.

BACKGROUND ART In general, liquid crystal display devices have tended to be gradually widened due to their light weight, thinness, and low power consumption. Accordingly, the liquid crystal display device is widely used as a means for displaying a screen in portable computers, mobile phones, office automation equipment and the like.

In general, the liquid crystal display device displays a desired image on a screen by adjusting the amount of light transmitted according to image signals applied to a plurality of control switch elements arranged in a matrix.

The liquid crystal display includes a liquid crystal panel in which a color filter substrate as an upper substrate and a thin film transistor array substrate as a lower substrate are opposed to each other, and a liquid crystal layer is formed between the two substrates, and a scan signal and image information are supplied to the liquid crystal panel. It consists of the nine eastern to operate.

Since the liquid crystal display is a non-light emitting device that does not emit light by itself, in order to implement an image on the liquid crystal panel, a light source for supplying light to the liquid crystal panel behind the liquid crystal panel is required. Therefore, the liquid crystal display includes a back light assembly including a light source for supplying light to the liquid crystal panel, a light guide plate, an optical sheet, and the like for converting light emitted from the light source into uniform white light. do.

Light sources generating light in the backlight assembly include a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), and a light emitting diode (LED).

Conventionally, a cold cathode fluorescent lamp is mainly used as a light source of a backlight assembly, but in recent years, a liquid crystal display device employing a light emitting diode, which is advantageous in power consumption, weight, and luminance, as a light source of a backlight assembly according to the trend toward miniaturization, thinness, and light weight of a liquid crystal display device. Is growing.

Hereinafter, a conventional liquid crystal display device will be described with reference to the accompanying drawings.

As shown in FIG. 1, a conventional liquid crystal display device includes a liquid crystal panel 1 and an array of light emitting diodes 2 including a plurality of light emitting diodes 2 for supplying light to the liquid crystal panel 1. A printed circuit board 3 having the light emitting diode 2 mounted thereon, a lower cover 6 having the printed circuit board 3 fixed to an inner side thereof, and a lower cover 6 disposed inside the lower cover 6. The light guide plate 9 for guiding the light emitted from the light emitting diode 2 toward the liquid crystal panel 1, and the optical sheet 10 for converting the light emitted from the light guide plate 9 and supplying the light to the liquid crystal panel 1. And a reflection sheet 11 for reflecting light leaking into the lower portion of the light guide plate 9 and guiding the light to the inside of the light guide plate 9.

The light emitting diode 2 provided as a light source in a conventional general liquid crystal display device having the above configuration has advantageous conditions in terms of power consumption, weight, and luminance as described above. A large amount of heat is generated in the anode part of the array, and a large amount of power supplied to the light emitting diode 2 array is wasted due to heat generation, and thus, luminance of light emitted from the light emitting diode 2 is lowered. There is a problem that the characteristics of the light emitting diode 2 are changed due to heat because a lot of heat does not quickly escape to the outside.

Recently, in order to solve the above-described problems, the heat sink 12 and the heat radiation pad 13 are disposed on the rear surface of the printed circuit board 3 on which the light emitting diode 2 is mounted. Although a configuration has been proposed in which heat to be transferred to the lower cover 6 through the printed circuit board 3, the heat sink 12, and the heat dissipation pad 13, can be discharged to the outside of the lower cover 6. Heat generated when driving the diode 2 is transferred to the lower cover 6 through a plurality of paths such as the printed circuit board 3, the heat sink 12, and the heat radiation pad 13, and then, There is still a problem that the heat radiation efficiency is not high because it is emitted to the outside.

Accordingly, the present invention is to solve the above problems, an object of the present invention has a structure in which heat generated from the light emitting diode provided as a light source can be quickly released to the outside of the lower cover, it is supplied to the light emitting diode The amount of waste due to heat generation during power supply is minimized to improve the brightness of light emitted from the light emitting diodes, and to minimize the change in characteristics of the light emitting diodes due to heat, thereby providing a liquid crystal display device having improved screen display quality.

Liquid crystal display device according to an embodiment of the present invention for achieving the above object, the liquid crystal panel; A light emitting diode array disposed on at least one side of the lower portion of the liquid crystal panel to supply light to the liquid crystal panel; A printed circuit board on which the light emitting diode array is mounted; A first heat dissipation pad bonded to an anode portion of the LED array mounted on the printed circuit board and having thermal conductivity; A lower cover accommodating the printed circuit board so as to correspond to an inner side surface, and a portion of the inner bottom surface adhered to the first heat radiation pad; It is configured to include.

In the liquid crystal display according to the present invention having the above-described configuration, since the first heat dissipation pad is attached to the anode portion of the light emitting diode array and the lower cover is formed with the protrusion to which the first heat dissipation pad is attached, the LED array The heat generated especially at the anode portion of the heat transfer to the lower cover through a short path including the first heat dissipation pad and the protrusion is emitted to the outside of the lower cover, the heat generated mainly from the anode portion of the LED array is printed circuit Since the first heat dissipation pad and the protrusion are transferred to the lower cover without passing through the substrate and the heat dissipation plate, heat dissipation can be effectively performed.

Accordingly, the amount of waste caused by heat generation is minimized among the power supplied to the LED array, thereby improving the brightness of the light emitted from the LED, and minimizing the change in the characteristics of the LED due to heat to improve screen display quality. It has the advantage of being.

Hereinafter, a liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, a liquid crystal display according to a preferred embodiment of the present invention includes a liquid crystal panel 101; An array of light emitting diodes 102 arranged on at least one side of the lower portion of the liquid crystal panel 101 to supply light to the liquid crystal panel 101; A printed circuit board 103 on which the array of light emitting diodes 102 is mounted; A first heat radiation pad 104 bonded to an anode portion of the array of light emitting diodes 102 mounted on the printed circuit board 103 and having thermal conductivity; And a lower cover 106 accommodating the printed circuit board 103 so as to correspond to an inner side surface, and a portion of the inner bottom surface adhered to the first heat dissipation pad 104. It is configured to include.

Each component of the liquid crystal display according to the preferred embodiment of the present invention having such a configuration will be described in detail as follows.

Referring to FIG. 2, the liquid crystal panel 101 includes a color filter substrate 101a which is an upper substrate and a thin film transistor array substrate 101b which is a lower substrate, and the two substrates 101a and 101b are not shown in detail. The liquid crystal layer is formed between the layers.

A plurality of light emitting diodes 102 for supplying light to the liquid crystal panel 101 are disposed on at least one side of the lower portion of the liquid crystal panel 101, and the plurality of light emitting diodes 102 are printed circuit boards 103. It is mounted on.

Referring to FIG. 3, the light emitting diodes 102 are mounted in series on a printed circuit board 103 to form an array, and wirings for connecting the light emitting diodes 102 in series on the printed circuit board 103. Is formed, and a power supply voltage line connected to the anode of the light emitting diode 102 positioned on the leftmost side (see Fig. 3) in the array of light emitting diodes 102 is formed, and the rightmost side of the light emitting diode 102 array (Fig. 3). And a base voltage wiring connected to the cathode of the light emitting diode 102 located in the third reference).

The power supply line connected to the anode of the light emitting diode 102 located on the leftmost side of the array of light emitting diodes 102 is the anode portion 105 of the array of light emitting diodes 102 and the light emitting diode 102 located on the rightmost side. The ground voltage line connected to the anode of is the cathode portion of the array of light emitting diodes 102.

Referring to FIG. 2, a first heat radiation pad 104 is adhered to an anode portion 105 of the light emitting diode 102 mounted on the printed circuit board 102, and the first heat radiation pad 104 is It is desirable to have thermal conductivity and insulation.

The liquid crystal display according to the preferred embodiment of the present invention includes a case for accommodating, fixing and protecting a plurality of components such as the printed circuit board 103 and the liquid crystal panel 101. The case includes a lower cover 106 for receiving a printed circuit board 103 on which a light emitting diode 102 is mounted, a panel guide 107 coupled to the lower cover 106 for receiving a liquid crystal panel 101, and The upper cover 108 covers an edge of the liquid crystal panel 101 and covers an upper portion and a side portion of the panel guide 107.

Among the plurality of components constituting the case, a printed circuit board 103 on which the light emitting diode 102 is mounted is received and fixed to correspond to an inner side of the lower cover 106, and an inner bottom of the lower cover 106 is fixed. Some areas of the face are bonded to the first heat dissipation pad 104.

A part of the inner bottom surface of the lower cover 106 will be described in detail with reference to FIGS. 2 and 4 with respect to the adhesive to the first heat dissipation pad 104.

2, a protrusion 106a1 including a surface 106a1 parallel to the front surface of the first heat radiation pad 104 is formed on an inner bottom surface of the lower cover 106, and the protrusion 106a is formed. The front surface of the first heat dissipation pad 104 is bonded to the surface of the substrate, whereby the anode portion 105 of the array of light emitting diodes 102 mounted on the printed circuit board 103 is lowered through the first heat dissipation pad 104. The heat generated in the anode portion 105 of the array of light emitting diodes 102 may be connected to the protrusion 106a of the cover 106, and the lower cover may be formed through the first heat dissipation pad 104 and the protrusion 106a. It is delivered to the 106 is to be discharged to the outside of the lower cover 106.

An inner bottom surface of the lower cover 106 may include a first region in which the printed circuit board 103 is disposed, a second region in which the reflecting plate 111, the light guide plate 109, and the optical sheet 110 are disposed; And a third area, which is a boundary between the first area and the second area, wherein the first area is located at a lower position than the second area and the third area is inclined, and the protrusion 106a is formed with the second area. It is provided where the third area meets.

In the above description of the liquid crystal display according to the exemplary embodiment of the present invention, the protrusion 106a is parallel to the front surface of the first heat dissipation pad 104 where the second and third regions of the lower cover 106 meet. Although one example is formed to include the surface 106a1, the present invention is not limited thereto, and the protrusion 206a of the lower cover 206 may be formed as shown in FIG. 4 without departing from the gist of the present invention. Various examples, such as an example of forming a pillar-shaped protrusion that protrudes upward from the first region of the inner bottom surface of the lower cover 206 to be bonded to the front surface of the first heat radiation pad 204, may be possible.

Referring to FIG. 2, the light guide plate 109, the optical sheet 110, and the reflective sheet 111 are accommodated in the lower cover 106 as described above. The light guide plate 109 may include a light emitting diode ( The traveling path of the light emitted from 102 is changed to guide the liquid crystal panel 101. The optical sheet 110 diffuses and condenses the light from the light guide plate 109 and then supplies the light to the liquid crystal panel 101. The reflective sheet 111 reflects light leaking into the lower portion of the light guide plate 109 into the light guide plate 109.

In addition, the lower cover 106 has a heat dissipation structure including the first heat dissipation pad 104 and the protrusion 106a in order to effectively dissipate heat generated from the light emitting diodes 102. Heat dissipation plate 112 bonded to the back of the), and the second heat dissipation pad 113 adhered to the inner side of the bottom and the bottom cover 106 of the heat dissipation plate 112 may be further provided. The heat dissipation plate is preferably formed of aluminum (Al), and the second heat dissipation pad 113 preferably has thermal conductivity and insulation, similarly to the first heat dissipation pad 104.

The liquid crystal display according to the preferred embodiment of the present invention as described above is provided with a first heat radiation pad 104 bonded to the anode portion 105 of the array of light emitting diodes 102 and the first heat radiation pad 104 Is formed in the lower cover 106, so that heat generated particularly in the anode portion 105 of the array of light emitting diodes 102 is transferred through the first heat dissipation pad 104 and the protrusion 106a. By being transferred to the lower cover 106 and released to the outside, most of the heat mainly generated in the anode portion 105 of the array of light emitting diodes 102 is printed circuit board 103, the heat sink 112 and the second heat radiation pad 113. Without passing through the first heat dissipation pad 104 and the projection 106a through the lower cover 106, the heat dissipation is effectively achieved, the amount of waste due to heat generation during power is minimized in the light emitting diode 102 The brightness of the emitted light is improved, The change in characteristics of the light emitting diode 102 due to heat is minimized to improve the screen display quality.

1 is a cross-sectional view showing a conventional general liquid crystal display device.

2 is a cross-sectional view showing a liquid crystal display device according to a preferred embodiment of the present invention.

3 is a perspective view illustrating a printed circuit board of FIG. 2, wirings and light emitting diodes formed on the printed circuit board.

4 is a cross-sectional view showing another example of the protrusion formed on the lower cover of FIG.

** Description of the symbols for the main parts of the drawings **

101: liquid crystal panel 102: light emitting diode

103: printed circuit board 104, 204: first heat dissipation pad

105: anode part of the LED array

106,206: lower cover 106a, 206a: protrusion

107: panel guide 108: top cover

109: light guide plate 110: optical sheet

111: reflective sheet 112: heat sink

113: second heat dissipation pad

Claims (8)

A liquid crystal panel; A light emitting diode array disposed on at least one side of the lower portion of the liquid crystal panel to supply light to the liquid crystal panel; A printed circuit board on which the light emitting diode array is mounted; A first heat dissipation pad bonded to an anode portion of the LED array mounted on the printed circuit board and having thermal conductivity; And A lower cover accommodating the printed circuit board so as to correspond to an inner side surface and a portion of the inner bottom surface adhered to the first heat radiation pad; Liquid crystal display device comprising a. According to claim 1, wherein the area of the bottom surface of the lower cover is bonded to the first heat radiation pad is a protrusion including a surface parallel to the front surface of the first heat radiation pad, the surface of the protrusion is bonded to the first heat radiation pad Liquid crystal display device characterized in that. The method of claim 2, further comprising a light guide plate for guiding the light emitted from the LED array toward the liquid crystal panel, The inner bottom surface of the lower cover includes a first region in which a printed circuit board is disposed, a second region in which a light guide plate is disposed, and a third region which is a boundary between the first region and the second region. The zone is at a lower position than the second zone, And the protrusion is provided where the second area and the third area meet each other. The liquid crystal display of claim 2, wherein the protrusion is a protrusion protruding upward from a bottom surface of the lower cover. The method of claim 4, further comprising a light guide plate for guiding the light emitted from the LED array toward the liquid crystal panel, The inner bottom surface of the lower cover includes a first area in which a printed circuit board is disposed, a second area in which a light guide plate is disposed, and a third area that is a boundary between the first area and the second area. The zone is at a lower position than the second zone, The protrusion is provided in the first area. The liquid crystal display of claim 2, wherein the protrusion is formed of the same material as the lower cover. The liquid crystal display of claim 1, further comprising a heat dissipation plate adhered to a rear surface of the printed circuit board, and a second heat dissipation pad adhered to a rear side of the heat dissipation plate and an inner side surface of the lower cover. Device. The liquid crystal display device according to claim 7, wherein the heat sink is formed of aluminum (Al).

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