DETAILED DESCRIPTION OF THE INVENTION

[0031] Reference will now be made in detail to illustrative, non-limiting embodiments of the present invention, which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

[0032] FIG. 2 is an exploded perspective view of a PDP assembly according to an illustrative, non-limiting embodiment of the present invention.

[0033] The PDP assembly 10 of the present invention includes a PDP 20 on which images are displayed, a base panel 40 in front of which the PDP 20 is disposed, and a sheet 30 which is disposed between the PDP 20 and the base panel 40 to transfer heat.

[0034] As illustrated in FIG. 3 , in the PDP 20 , a plurality of partition walls 22 are regularly formed between a pair of glass substrates 21 provided with an X electrode 21 a and a Y electrode 21 b , respectively, to form a plurality of pixels 23 , and each of the pixels 23 is sealed with the interior thereof being filled with high pressure electric discharge gas. Each pixel 23 is provided with a fluorescent material 24 that emits one of red, green and blue visible light when ultraviolet rays are irradiated to the pixel 23 . Accordingly, when voltage is applied between the X electrode 21 a and the Y electrode 21 b , plasma discharge is performed through the electric discharge gas in the pixel 23 , and ultraviolet rays are generated. The generated ultraviolet rays collide with the fluorescent material 24 , and consequently visible rays are generated by the collision between the ultraviolet rays and the fluorescent material 24 .

[0035] Referring to FIG. 4, a variety of electronic devices are mounted on the back of the base panel 40 to apply voltage to each pixel 23 . For the electronic devices mounted on the back of the base panel 40 , there are a Switched Mode Power Supply (SMPS) 50 that supplies power to the PDP assembly 10 and circuit boards 60 a and 60 b that control display by selectively applying and removing voltage between the X electrode 21 a and the Y electrode 21 b.

[0036] In this case, the circuit boards 60 a and 60 b include an X circuit board 60 a that applies voltage to the X electrode 21 a of each pixel 23 and a Y circuit board 60 b that applies voltage to the Y electrode 21 b of each pixel 23 .

[0037] As shown in FIG. 5, a MOSFET 70 is substantially fabricated in the form of a plate. A plurality of connection lines 71 are extended from the MOSFET 70 to be connected to circuit boards 60 a and 60 b . The wide surface of the MOSFET 70 is tightly attached to a heat sink 80 by a fastening means such as a screw so that heat generated in the MOSFET 70 is transferred to and radiated through the heat sink 80 .

[0038] The heat sink 80 is fixedly attached to the circuit boards 60 a and 60 b . The heat sink 80 includes a base portion 81 fastened to the circuit boards 60 a and 60 b , a contact portion 82 upwardly extended from the base portion 81 and brought into contact at one side thereof with the MOSFET 70 to receive heat generated in the MOSFET 70 , and a plurality of heat radiation fins 83 a , 83 b and 83 c extended from the contact portion 82 to a certain extent, in parallel with the base portion 81 to radiate heat.

[0039] The base portion 81 of the heat sink 80 is fixedly attached to the circuit boards 60 a and 60 b and additionally serves as a heat radiation fin.

[0040] The heat radiation fins 83 a , 83 b and 83 c are fabricated in the form of a plate. The plurality of heat radiation fins 83 a , 83 b and 83 c are arranged in parallel with each other in a vertical direction, and spaced apart from each other by a certain interval to desirably radiate heat. In this illustrative, non-limiting embodiment, the number of the heat radiation fins 83 a , 83 b and 83 c is three.

[0041] In this case, the uppermost heat radiation fin of the three heat radiation fins 83 a , 83 b and 83 c is designed to have a width L 2 that is smaller than the width L 1 of the central and lowermost heat radiation fins of the three heat radiation fins 83 a , 83 b and 83 c.

[0042] The vibration of a heat radiation fin 83 a , 83 b or 83 c can be increased in proportion to the distance thereof from the base portion 81 . Additionally, if the heat radiation fins 83 a , 83 b or 83 c vibrate with an amplitude that is greater than a certain amplitude, air is vibrated and noise is generated. Accordingly, when the width of the uppermost heat radiation fin 83 a is designed smaller than each of the other heat radiation fins 83 b and 83 c , the vibration magnitude of the uppermost heat radiation fin 83 a is reduced to a value that is similar to the vibration magnitude value for each of the central and lowermost heat radiation fins 83 b and 83 c.

[0043] The widths of the central and lowermost heat radiation fins 83 b and 83 c are designed to be the same. The central and lowermost heat radiation fins 83 b and 83 c vibrate with amplitudes that are smaller than the vibration amplitude of the uppermost heat radiation fin 83 c . Therefore, the central and lowermost heat radiation fins 83 b and 83 c do not generate noise. Additionally, they are designed to have the same width in consideration of ease of fabrication.

[0044] In this illustrative, non-limiting embodiment, the expressions “upper” and “lower” are used to represent the relative positions of the elements, but are not used to limit the configuration of the heat sink 80 in detail.

[0045] Additionally, although in this illustrative, non-limiting embodiment the number of the heat radiation fins 83 a , 83 b and 83 c has been described as being three, the number of the heat radiation fins is not limited to three. Accordingly, after the number of the heat radiation fins is determined depending upon the overall design of the heat sink, the widths of the heat radiation fins may be determined to allow each of the vibration amplitudes of the heat radiation fins to be less than a certain level, so noise generated by the heat sink 80 may be reduced to less than a certain level.

[0046] Furthermore, although in this illustrative, non-limiting embodiment the central and lowermost heat radiation fins 83 b and 83 c are designed to have the same width, the widths of the heat radiation fins 83 a , 83 b and 83 c could be designed to be inversely proportional to the distances thereof from the base portion 91 as illustrated in FIG. 7 .

[0047] Hereinafter, operations and effects of the heat sink for electronic devices, and circuit board and PDP assembly, each equipped with the heat sink are described in detail with reference to the accompanying drawings.

[0048] A plurality of MOSFETs 70 provided on the X and Y circuit boards 60 a and 60 b generate heat and vibration by their on/off switching operation.

[0049] Generated heat is transmitted to the heat sink 80 and dissipated to the air through the heat sink 80 , so the overheating of the MOSFETs 70 can be prevented.

[0050] Vibration generated in the MOSFETs 70 along with the heat is transmitted to the heat sink 80 , and the heat radiating fins 83 a , 83 b and 83 c provided in the heat sink 80 are vibrated by the vibration transmitted from the MOSFET 70 .

[0051] In this case, the base portion 81 of the heat sink 80 is fixedly attached to the circuit boards 60 a and 60 b , so the heat radiation fins 83 a , 83 b or 83 c vibrate with a magnitude that is proportional to the distance between the heat radiation fins 83 a , 83 b or 83 c and the base portion 81 of the heat sink 80 .

[0052] Since the width L 2 of the uppermost heat radiation fin 83 a that is most distant from the base portion 81 is designed to be smaller than the width L 1 of the central and lowermost heat radiation fins 83 b and 83 c , the vibration magnitude of the uppermost heat radiation fin 83 a is rendered similar to the vibration magnitude of the central and lowermost heat radiation fins 83 b and 83 c , as depicted in FIG. 6 , thus preventing the occurrence of noise.

[0053] FIG. 8 is a graph that illustrates the noise of a conventional heat sink that has three heat radiation fins each with the same width compared to the noise of the heat sink of the present invention in which the width L 2 of the uppermost fin 83 a is designed to be less than the width L 1 of the central and lowermost fins 83 b and 83 c.

[0054] In FIG. 8, a solid line represents the experimental values of the noise of the heat sink 80 of the present invention, while a dotted line represents the experimental values of the noise of the conventional heat sink 80 .

[0055] As illustrated in portion “A” of FIG. 8 , the peak value of the noise of the heat sink of the present invention is reduced to a value that is considerably smaller than the peak value of the noise of the conventional heat sink.

[0056] As described in detail above, when a vibration is transmitted from the MOSFET, the heat radiation fins of the heat sink of the present invention are designed to have widths so that the vibration magnitudes of the heat radiation fins are restricted to less than a certain level. Accordingly, noise that may be caused by the vibration can be reduced.

[0057] Furthermore, as the noise generated in the heat sink is reduced, noise that may be generated in the circuit board and the PDP panel, each equipped with the heat sink of the present invention can be reduced.

[0058] Although a few exemplary embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these non-limiting embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.