KR20080101049A - Heat dissipation device of LCD - Google Patents

Abstract

The present invention relates to a technology for dissipating heat generated by a switching element installed in an inverter of a liquid crystal display using a heat dissipation member. This invention is achieved by providing a heat dissipation member made of aluminum, a PC or a heat resistant plastic part in a switching transistor of a backlight inverter of a liquid crystal display device.

Description

Heat dissipation device for liquid crystal display device {HEAT DISSIPATION DEVICE FOR LIQUID CRYSTAL DISPLAY}

1 is a plan view showing the layout of an inverter in a conventional liquid crystal display device.

Figure 2a is a plan view showing the layout of the inverter according to an embodiment of the present invention.

Figure 2b is a plan view showing the layout of an inverter according to another embodiment of the present invention.

Figure 3a and Figure 3b is a plan view showing a through-hole installation example of the heat radiation member according to the present invention.

Figure 4 is a heat dissipation test table of the inverter by the heat dissipation member of the present invention.

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

20: PCB for inverter 21: switching control unit

22: switching transistor portion 23A, 23B: heat dissipation member

24: transformer section

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for dissipating heat generated by an inverter in a liquid crystal display device, and more particularly, to a heat dissipation device for a liquid crystal display device suitable for dissipating heat generated in a switching element portion of an inverter using a heat dissipation member. .

In general, the liquid crystal display (LCD) has been gradually expanded due to its light weight, thinness, low power consumption, and the like. According to this trend, LCDs are widely used in office automation equipment, audio / video equipment, and the like. The LCD displays a desired image on the screen by adjusting the transmission amount of the light beam according to an image signal applied to the control switches arranged in a matrix form.

However, the LCD is not a display device that emits light by itself, and thus requires a light source such as a backlight unit. An example of a light source used as the backlight unit may be a Cold Cathode Fluorescent Tube (CCFL). The backlight lamp is a light source tube using a cold cathode emission phenomenon, and low heat generation, high brightness, long life, full color is easy. The liquid crystal display using such a lamp uses a direct type backlight unit using a plurality of lamps according to the trend of larger size.

The direct type backlight unit has a problem in that only some of them are driven by discharge characteristics when driving multiple CCFLs in parallel using a single transformer. In order to solve this problem, by attaching the same capacitor (Ballast Capacitor) to the positive electrodes of a plurality of CCFLs to form the same equivalent circuit as the External Electrode Fluorescent (EEFL) by using a plurality of CCFLs A lamp driving device of a liquid crystal display device capable of parallel driving of them has been proposed.

Here, the external electrode fluorescent lamp is turned on by applying an AC waveform to the external electrode. That is, the external electrode fluorescent lamp is discharged in the discharge space inside the glass tube by a high frequency electric field applied to a pair of external electrodes, and the phosphor coated on the inner wall of the glass tube by the ultraviolet rays generated by the discharge The light is emitted to generate visible light.

In the related art, the fluorescent lamp is mainly used as a backlight, but recently, a new device such as a light emitting diode (LED) has been used.

In general, an inverter is mainly used as the driving device of the backlight as described above. FIG. 1 is a plan view showing the layout thereof, and as shown therein, the switching control unit 11 for controlling the switching operation of the switching transistor unit 12. Wow; A switching transistor section 12 which performs switching operation under the control of the switching control section 11; By the switching operation of the transistor in the switching transistor section 12, it is composed of a transformer section 13 for converting an AC power source into a high voltage AC power source and outputting it to the backlight side.

The switching control unit 11, the switching transistor unit 12, and the transformer unit 13 are provided on the inverter PCPC 10.

The switching control unit 11 outputs a control signal for controlling the switching operation of the switching transistor FET in the switching transistor unit 12.

As a result, a switching operation of the transistor FET of the switching transistor unit 12 is performed. In FIG. 1, the transistor FET is implemented in four pairs.

The transformer of the transformer unit 13 is driven by the switching operation of the transistor FET in the switching transistor unit 12, whereby the DC power supplied from the outside is converted into AC power having a level corresponding to the turns ratio of the transformer. And output.

The backlight is driven by the high voltage AC power generated through the above process, whereby the light of the target brightness is generated in the backlight and is reflected on the liquid crystal panel.

However, a relatively large amount of heat is generated from the switching operation of the transistor FET in the switching transistor unit 12. Furthermore, due to the recent increase in power consumption due to the large size of the LCD panel, the switching transistor unit 12 has such a large load that more heat is generated therefrom.

Nevertheless, in the conventional liquid crystal display device, there is no device for properly discharging the high heat generated by the switching element of the inverter, which makes it difficult to stably drive the switching element.

In order to solve this problem, conventionally, a method of reducing the amount of heat generated by additionally using a switching element has been adopted, but in this case, there is a problem in that the cost increases.

Accordingly, an object of the present invention is to provide a heat radiating member to a switching element that generates a large amount of heat in an inverter, so that the heat can be released.

The present invention for achieving the above object is characterized in that a heat dissipation member is provided in the switching element portion in order to discharge heat generated in the switching element portion provided in the backlight inverter of the liquid crystal display device.

The heat dissipation member is characterized in that formed of any one of aluminum, PCB or plastic having high heat resistance.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2A is a plan view of an inverter showing an embodiment of a heat dissipating device of a liquid crystal display according to the present invention. As shown therein, a switching control unit 21 for controlling a switching operation of the switching transistor unit 22 and ; A switching transistor section 22 which performs switching operation under the control of the switching control section 21; A heat dissipation member (23A) fixedly installed on top of the transistors (FETs) of the switching transistor unit (22) for dissipating heat generated by the transistors (FETs) to the outside; By the switching operation of the switching transistor section 22, the transformer section 24 converts the AC power into a high voltage AC power and outputs it to the backlight side.

The heat dissipation member 23A is characterized by having a plurality of heat dissipation holes H1 in the horizontal and vertical directions.

FIG. 2B is a plan view of an inverter showing another embodiment of the heat dissipation device of the liquid crystal display according to the present invention. As shown therein, a switching controller 21 for controlling the switching operation of the switching transistor unit 22; A switching transistor section 22 which performs switching operation under the control of the switching control section 21; A heat dissipation member (23B) protruding the transistor (FET) of the switching transistor unit 22 and fixedly installed in close contact with the inverter PC (20) and dissipating heat generated by the transistor (FET) to the outside; By the switching operation of the switching transistor section 22, the transformer section 24 converts the AC power into a high voltage AC power and outputs it to the backlight side.

The heat dissipation member 23B includes a plurality of heat dissipation holes H1 in the horizontal and vertical directions, and also has a hole H2 for protruding the transistor FET to closely contact the inverter PC 20. It features.

Referring to Figures 3 and 4 attached to the operation of the present invention configured as described above in detail as follows.

The switching control unit 21, the switching transistor unit 22, and the transformer unit 24 are provided on the inverter PCB 20.

The switching control unit 21 outputs a control signal for controlling the switching operation of the transistor FET in the switching transistor unit 22.

As a result, a switching operation of the transistor FET of the switching transistor unit 22 is illustrated. In FIGS. 2A and 2B, the switching element FET is implemented in four pairs.

The transformer of the transformer unit 24 is driven by the switching operation of the transistor (FET) in the switching transistor unit 22, whereby the DC power supplied from the outside is converted into AC power having a level corresponding to the turns ratio of the transformer. And output.

The backlight is driven by the high voltage AC power generated through the above process, whereby the light of the target brightness is generated in the backlight and is reflected on the liquid crystal panel.

However, a relatively large amount of heat is generated from the switching operation of the transistor FET in the switching transistor unit 22. Moreover, due to the recent increase in power consumption due to the enlargement of the LCD panel, the switching transistor unit 22 is loaded with such much load, and more heat is generated therefrom.

However, in the present invention, the heat generated by the switching operation of the transistor FET in the switching transistor unit 22 is radiated through the heat dissipation member 23A so that the area of the switching transistor unit 22 on the inverter PC 20 may be reduced. The temperature does not rise above a certain value, which will be described in more detail as follows.

2A illustrates an example in which the heat dissipation member 23A is disposed on the transistors FETs of the switching transistor unit 22. The material of the heat dissipation member 23A may be of various kinds, for example, aluminum, a plastic having high heat resistance, or a PC.

In this embodiment, part of the inverter PC 20 is used as the heat dissipation member 23A. That is, the PC ratio of the transformer unit 24 region existing in the surplus space among the inverter PC ratios 20 is cut by the required width, and the plurality of through holes H1 in the transverse and longitudinal direction are cut in the cut region as shown in FIG. 3A. After fabricating the heat dissipation member 23A formed thereon, the heat dissipation member 23A was formed and then coupled to the upper portions of the transistors (FETs) of the switching transistor unit 22 to form a single unit with the transformer unit 24.

There may be various methods of coupling the heat radiating member 23A to the upper portions of the transistors FETs of the switching transistor unit 22. For example, there is a method of bonding or bonding using a double tape.

Accordingly, heat generated in the transistors FETs is released into the air through the heat dissipation member 23A manufactured as described above by the switching operation of the transistors FETs in the switching transistor unit 22. Therefore, even when the switching operation of the transistor FET in the switching transistor section 22 is performed, the temperature of the switching transistor section 22 does not rise above a certain value.

4 is a comparative table showing how much heat dissipation effect is provided when the heat dissipation member 23A is provided in the switching transistor unit 22. Compared to the case where the heat dissipation member 23A is not provided, 4 to 6 are compared. It turns out that temperature dropped about degreeC.

In addition, FIG. 2B illustrates another example in which the heat dissipation member 23B is disposed on the transistors FETs of the switching transistor unit 22.

In the present embodiment, a part of the inverter PC 20 is used as the heat dissipation member 23B, but the transistor FET of the switching transistor unit 22 protrudes and the PC ratio of the switching transistor unit 22 region is used. The difference is that they are fixed in close contact with.

That is, as described above, the PCB of the transformer unit 24 region existing in the surplus space among the PCBs 20 for the inverter is cut by the required area, and the plurality of through-holes in the transverse and longitudinal directions (as shown in FIG. In addition to forming H1, a heat dissipation member 23B having another through hole H2 for protruding the transistor FET is formed in the middle thereof, and then the upper portion of the substrate in the area of the switching transistor 22 is formed. It was closely bonded to and formed integrally with the transformer portion 24.

The method of coupling the heat dissipation member 23B to the upper portion of the substrate in the region of the switching transistor portion 22 uses the same method as described above.

Accordingly, heat generated in the transistors FETs is released into the air through the heat dissipation member 23B manufactured as described above by the switching operation of the transistors FETs in the switching transistor unit 22. Therefore, even when the switching operation of the transistor FET in the switching transistor section 22 is performed, the temperature of the switching transistor section 22 does not rise above a certain value.

As described in detail above, the present invention provides a heat dissipation member in a switching element installed in a backlight inverter of a liquid crystal display device to dissipate heat generated by the switching element, thereby overheating the switching element. Is prevented.

Accordingly, the switching element portion can be driven in a more stable state, and the minimum switching element can be used without the PCB pattern and the additional heat dissipation design, thereby reducing the cost of the inverter. In addition, there is an effect of improving the design freedom of the transformer.

Claims (9)

A backlight inverter of a liquid crystal display device, comprising: a heat dissipation member included in the switching transistor unit for dissipating heat generated by the switching transistor unit of the backlight inverter. The heat dissipation device of claim 1, wherein the heat dissipation member is formed of any one of aluminum, PCB, and plastic having high heat resistance. The heat dissipation device of a liquid crystal display device according to claim 2, wherein the PC ratio includes a PC ratio of a transformer region in the inverter PC ratio. The heat dissipation device of claim 1, wherein the heat dissipation member is fixedly installed on the transistors of the switching transistor unit. The heat dissipation device of claim 4, wherein the heat dissipation member is fixed by a bond or a double tape when the heat dissipation member is fixedly installed on the transistors of the switching transistor unit. The heat dissipation device of claim 1, wherein the heat dissipation member protrudes the transistors of the switching transistor unit, and is fixedly installed in close contact with the PCB of the switching transistor unit region. The heat dissipation device of claim 6, wherein the heat dissipation member is fixed by a bond or a double tape when the heat dissipation member is fixedly installed in close contact with the PCB of the switching transistor unit region. The heat dissipation device of a liquid crystal display device according to claim 1, wherein the heat dissipation member has a plurality of heat dissipation holes. The heat dissipation device of claim 1, wherein the heat dissipation member includes through holes for protruding the transistors of the switching transistor unit.

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