KR100688979B1 - Backlight unit - Google Patents

Abstract

The present invention relates to a backlight unit including an LED module having a plurality of LEDs, the heat conducting member being heat-transferred with the LED module; A cooling pipe in thermal contact with the heat conducting member and containing a heat transfer fluid; A radiator communicating with the cooling pipe to receive heat; And a circulation pump provided to circulate the heat transfer fluid between the cooling pipe and the radiator. As a result, the heat dissipation is quick and uniform, thereby improving the performance of the LED and providing a backlight unit capable of maintaining color uniformity.

Description

Backlight Unit {BACKLIGHT UNIT}

1 is a perspective view showing a first embodiment according to the present invention;

2 is a perspective view showing a second embodiment according to the present invention;

3 is a perspective view of a cooling fan according to the present invention;

4 is a cross-sectional view of a heat pipe according to the present invention.

* Explanation of symbols for the main parts of the drawings

10: backlight unit 13: LED

15 LED module 17 liquid crystal display panel

19: light guide plate

20: heat pipe

31: cooling piping 33: radiator

35: circulation pump

41 cooling fan 43 casing

45: pipe receiving device 47: LED module support

The present invention relates to a backlight unit, and more particularly, to a cooling method of an LED module.

BACKGROUND ART A liquid crystal display panel is widely used for a monitor which forms an image on a computer or a TV. In general, a liquid crystal display panel has a backlight unit on its back, and the backlight unit generates light from the rear of the liquid crystal display panel to the liquid crystal display panel. Recently, a backlight unit has been developed using a light emitting diode (LED) as a light source.

As such LEDs are used as a light source, there is a problem that they have a high heat generation amount. In recent years, the user tends to prefer a large-sized liquid crystal display panel, so that the number of LEDs used in the backlight unit increases, so that the amount of heat generated also increases.

A structure for equalizing a temperature by removing heat generated from an LED light source is disclosed in Korean Patent Publication No. 2003-79599 (October 10, 2003). Heat pipes are provided to remove heat generated from the light source and to equalize the temperature. The cooling of the heat pipe consists of natural convection by external air.

Therefore, in the related art, since the cooling of the heat pipe depends on natural convection, a range in which heat generated from a light source can be transferred is limited, and there is a problem in that a temperature difference occurs between LEDs. In particular, in the case of a large sized backlight unit, there is a problem in that the temperature is effectively uniformed by removing heat generated from a plurality of LED light sources.

Accordingly, an object of the present invention is to provide a backlight unit capable of rapidly and uniformly dissipating heat, thereby improving the performance of the LED and maintaining color uniformity.

The object is, according to the present invention, a backlight unit comprising a LED module having a plurality of LEDs, the heat conducting member and the heat transfer member and the LED module; A cooling pipe in thermal contact with the heat conducting member and containing a heat transfer fluid; A radiator communicating with the cooling pipe to receive heat; It is achieved by a backlight unit having a circulation pump provided to circulate the heat transfer fluid between the cooling pipe and the radiator.

Here, it is preferable to further include a cooling fan provided to cool the radiator.

In addition, the heat conductive member is preferably a heat pipe.

In addition, the cooling pipe, the radiator and the pump preferably comprises a plurality.

In addition, the heat pipe and the heat transfer area is widened, it is preferable to have a pipe receiving device recessed to indent the heat pipe.

Hereinafter, a backlight unit according to a first embodiment of the present invention will be described with reference to the accompanying drawings.

In various embodiments, like reference numerals refer to like elements, and like reference numerals refer to like elements in the first embodiment and may be omitted in other embodiments.

As shown in FIGS. 1 and 3, the backlight unit 10 according to the present invention includes a LED module 15 having a plurality of LEDs 13, a heat conducting member that is heat-transferred from the LED module 15, and Cooling pipe 31 in thermal contact with the heat conducting member and containing the heat transfer fluid, a radiator 33 communicating with the cooling pipe 31 to receive heat, and a heat transfer fluid between the cooling pipe 31 and the radiator 33. The circulation pump 35 which circulates is provided. In addition, as illustrated in FIG. 3, the backlight unit 10 further includes a cooling fan 41 to cool the radiator 33.

The backlight unit 10 is provided on the rear surface of the liquid crystal display panel 17 used in a monitor for forming an image on a computer or TV, such as a computer or a TV, and generates light to the liquid crystal display panel 17. The backlight unit 10 has been developed a method of using a light emitting diode (LED) as a light source. In the present invention, the diffusion sheet (not shown) provided to be spaced apart from the upper side of the LED module 15 to diffuse the light generated from the LED module 15, the optical sheet (not shown) provided to be spaced apart from the upper side of the diffusion sheet, Descriptions will be omitted for a plurality of reflecting plates (not shown) and the like provided to be inclined to reflect light emitted to the side surfaces between the diffusion sheet and the optical sheet.

The LEDs 13 are provided in plural and generate light having any one color of R (Red), G (Green), and B (Blue), respectively. However, each LED 13 may generate white light, or may generate light of a different color. The plurality of LEDs 13 emits heat of high temperature in the process of generating light. As shown in FIG. 1, the LED 13 is disposed on the side surface of the backlight unit 10, and the light reflected through the light guide plate 19 is displayed on the liquid crystal display panel 17. The LED 13 is an embodiment of a light source, and the type of heat generated in the present invention may include various types of lamps capable of generating light, not limited to the LED.

The LED module 15 is provided with a long plate-shaped LED substrate (not shown) and a circuit pattern (not shown) for driving the LED 13 on the LED surface so as to be coupled and supported by the plurality of LEDs 13. Each of the LEDs 13 is disposed spaced apart from each other in the LED module 15. The LED substrate is made of a material having good thermal conductivity in order to dissipate heat generated from the LED 13. The LED substrate is not limited to an aluminum material having good thermal conductivity as an example of the present invention, and may be formed of another material having good thermal conductivity.

The liquid crystal display panel 17 receives the light of the LED 13 to form an image to the user.

The light guide plate 19 receives the light emitted from the lamp using a transparent acrylic panel and distributes the light evenly over the entire area of the panel through a pattern having a predetermined area and shape deposited on the acrylic surface.

The heat conduction member (not shown) is in contact with the LED module 15 for heat transfer. As the material of the heat conductive member, not only aluminum having good thermal conductivity but also various known materials that are in thermal contact with the LED module 15 may be adopted. The heat conduction member may be employed in various kinds of well-known as well as a shape having a protruding heat dissipation fin attached to increase the heat dissipation area. The heat conducting member is preferably a tubular heat pipe 20 having a circular or elliptical cross section in thermal contact with the LED module 15.

As shown in FIG. 4, the heat pipe 20 is provided to be press-fitted into the recessed pipe receiving tool 45 formed to widen the heat transfer area with the heat pipe 20. The pipe receiving tool 45 is recessed in the LED module support 47 for supporting the LED module 15 so that the heat pipe 20 is press-fitted. The heat pipe 20 is provided in a tubular shape and is sealed by putting a working fluid therein. The heat pipe 20 is provided in the back surface of the LED module 15 corresponding to each row of the LED module 15. That is, the heat pipe 20 may be provided in plurality. Thus, the heat pipe 20 is in contact with the LED module 15 and at the same time may be pressed into the pipe receiving device 45 having a large heat transfer area to cool the LED modules 15 to a substantially uniform temperature.

The cooling pipe 31 is in thermal contact with the heat pipe 20 and a heat transfer fluid is accommodated. The cooling pipe 31 transfers the heat received from the LED module 15 to the heat pipe 20 to release some heat to the outside, and transfers the heat remaining in the heat pipe 20 through heat contact with the heat pipe 20. The heat pipe 20 is cooled. Thus, the cooling pipe 31 cools the heat that the heat pipe 20 does not discharge, and the fluid inside the heat pipe 20 circulates to be in thermal contact with the LED module 15 again at a lower temperature. Therefore, since the heat pipe 20 cooled by the cooling pipe 31 contacts and heat transfers the LED module 15 at a lower temperature, the LED module 15 may be cooled more quickly and effectively.

The radiator 33 communicates with the cooling pipe 31 and cools the heat transfer fluid whose temperature is increased by thermal contact with the heat pipe 20. The radiator 33 is made of a good thermal conductive material to easily release heat. Radiator 33 is an example of the present invention is provided with a good thermal conductivity aluminum material, but may be provided with a different material. The radiator 33 is provided with a plurality of heat dissipation fins (not shown) provided to increase the contact area with air, and of course, various types known for this purpose may be employed. As shown in FIG. 3, the radiator 33 may be provided with at least one cooling fan 41. As shown in FIG. 3, when the cooling fan 41 is installed, the cooling fan 41 may provide a casing 43 in which the cooling fan 41 may be installed and an air flow path is formed.

The circulation pump 35 is provided between the cooling pipe 31 and the radiator 33 to circulate the heat transfer fluid. The circulation pump 35 may be disposed on the rear surface of the backlight unit 10. The circulation pump 35 may be controlled to operate for a predetermined time after the power of the LED 13 is turned off.

As shown in FIG. 3, the cooling fan 41 is disposed at one side of the casing 43 of the radiator 33. The cooling fan 41 blows toward the radiator 33 to cool the heat transferred from the heat pipe 20. That is, the cooling fan 41 cools the radiator 33 by forced convection to quickly dissipate heat generated in the heat pipe 20. The cooling fan 41 is provided in plurality in correspondence with the plurality of radiators 33. The cooling fan 41 may be controlled to operate for several minutes after the power of the LED 13 is turned off.

The heat dissipation process of the backlight unit 10 according to the first embodiment of the present invention by the configuration as described above is as follows.

First, a plurality of LEDs 13 are turned on to generate heat. Then, heat generated from the LED 13 is transferred to the LED module 15 provided behind the LED 13 to generate heat. At this time, the LED modules 15 may be cooled by the heat pipe 20. In addition, the cooling pipe 31 receives heat transfer fluid cooled by the cooling fan 34 in the radiator 33 and circulates to the circulation pump 35 to radiate heat in thermal contact with the heat pipe 20. As a result, the LED module 15 is uniformly cooled and the heat pipe 20 can be cooled more effectively and quickly.

As such, the backlight unit 10 according to the first embodiment of the present invention has a rapid and uniform heat dissipation, thereby improving performance of the LED 13 and minimizing a temperature difference to maintain color uniformity. In addition, each LED module 15 has a temperature sensor (not shown) capable of sensing temperature, and each radiator (based on a result detected by the temperature sensor so that the temperature between each LED module 15 can be maintained uniformly). A control unit (not shown) for controlling the wind speed of the cooling fan 41 arranged in 33 may be further provided.

As shown in FIG. 2, the backlight unit 10 according to the second embodiment of the present invention includes a plurality of LED modules 15 disposed on the rear surface of the liquid crystal display panel 17 having a plurality of LEDs 13. , A heat conduction member (not shown) corresponding to the plurality of LED modules 15, respectively, for heat transfer, a cooling pipe 31 in thermal contact with the heat conduction member, and in which a heat transfer fluid is received, and communicating with the cooling pipe 31 to receive heat. The circulation pump 35 which circulates a heat transfer fluid between the radiator 33 and the cooling piping 31 and the radiator 33 is provided. As shown in FIG. 3, the backlight unit 10 further includes a cooling fan 41 to cool the radiator 33.

The second embodiment of the present invention differs from the first embodiment in that a plurality of LED modules 15 and a plurality of heat conductive members corresponding to the plurality of LED modules 15 are provided on the rear surface of the liquid crystal display panel 17. Therefore, the description of the same configuration as in the first embodiment is omitted.

In the LED 13, as shown in FIG. 2, light generated from the rear surface of the backlight unit 10 is displayed on the liquid crystal display panel 17. The LEDs 13 are spaced apart from the rear surface of the backlight unit 10 and mounted on the plurality of LED modules 15.

As shown in FIG. 2, the LED module 15 is located on the rear surface of the liquid crystal display panel 17. The LED module 15 is provided with a long plate-shaped LED substrate (not shown) and a circuit pattern (not shown) for driving the LED 13 on the LED surface so as to be coupled and supported by the plurality of LEDs 13. The LED modules 15 are arranged to be spaced apart from each other LEDs (13). The plurality of LED modules 15 are provided to be spaced apart from each other and are made of a material having good thermal conductivity to release heat generated from the LEDs 13. The LED substrate is not limited to an aluminum material having good thermal conductivity as an example of the present invention, and may be formed of another material having good thermal conductivity.

The heat conductive member (not shown) may be provided in various materials and shapes known as in the first embodiment, but is preferably provided as the heat pipe 20.

As shown in FIG. 4, the heat pipe 20 is provided to be press-fitted into the pipe receiving tool 45 recessed to widen the heat transfer area with the heat pipe 20. The pipe receiving tool 45 is provided such that the heat pipes 20 are press-fitted into the plurality of LED module supporters 47 supporting the plurality of LED modules 15, respectively. The heat pipe 20 is provided in a tubular shape and is sealed by putting a working fluid therein. The heat pipe 20 is provided in the back surface of the LED module 15 corresponding to each row of the LED module 15. That is, the heat pipe 20 may be provided in plurality. Thus, the heat pipe 20 is in contact with the LED module 15 and at the same time press-fitted to the pipe receiving device 45 having a large heat transfer area to cool the LED modules 15 to a substantially uniform temperature.

With the above configuration, the backlight unit 10 according to the second embodiment of the present invention has a different arrangement position of the LED 13 and the configuration of the heat pipe 20 as described above. Therefore, since the heat dissipation process of the second embodiment is the same as that of the first embodiment, description thereof is omitted.

As described above, the backlight unit 10 according to the second exemplary embodiment of the present invention has quick and uniform heat dissipation even when the LED module 15 is widely disposed on the rear surface of the liquid crystal display panel 17. Thus, the backlight unit 10 can improve the performance of the LED, it is possible to maintain the color uniformity by minimizing the temperature difference.

Although the backlight unit using LED was illustrated as the above embodiment, this invention is applicable also to the electronic device which is equipped with another kind of light source, and heat-radiates.

Therefore, according to the present invention, the cooling pipe 31, the radiator 33 and the circulation pump (not shown) to heat radiate heat contact with the heat pipe 20, as well as the heat pipe 20 heat radiation in thermal contact with the LED module 15 ( 35 is provided to provide a backlight unit 10 which can be quickly and uniformly radiated. Thus, the backlight unit 10 can improve the performance of the LED, it is possible to maintain the color uniformity by minimizing the temperature difference.

As described above, according to the present invention, the heat dissipation is made quickly and uniformly, thereby improving the performance of the LED and maintaining the color uniformity.

Claims (5)

In the backlight unit comprising an LED module having a plurality of LEDs, A heat conducting member which is heat-transferred with the LED module; A cooling pipe in thermal contact with the heat conducting member and containing a heat transfer fluid; A radiator communicating with the cooling pipe to receive heat; And a circulation pump provided to circulate the heat transfer fluid between the cooling pipe and the radiator. The method of claim 1, And a cooling fan provided to cool the radiator. The method of claim 1, The heat conducting member is a backlight unit, characterized in that the heat pipe. The method of claim 1, The cooling unit, the radiator and the pump is a backlight unit, characterized in that it comprises a plurality. The method according to any one of claims 1 to 4, Further comprising a module support for supporting the LED module, The module support is a backlight unit, characterized in that it has a pipe receiving device recessed to indent the heat pipe.

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