Heat dissipation device incorporating heat spreader   

Abstract: An exemplary heat dissipation device is adapted for dissipating heat generated by an electronic component mounted on a printed circuit board. The heat dissipation device includes a heat spreader and a fin set placed on the heat spreader. The heat spreader includes a base, a partition board hermetically placed on the base, and a covering plate hermetically placed on the partition board. A first chamber is defined between the base and the partition board, and a second chamber is defined between the partition board and the covering plate.

1. Technical Field

The present disclosure relates to heat dissipation devices, and more particularly to a heat dissipation device incorporating a heat spreader.

2. Description of Related Art

Electronic components, such as central processing units (CPUs) comprising numerous circuits operate at high speed and generate substantive heat. Under most circumstances, it is necessary to cool the electronic components in order to maintain safe operating conditions and assure that the electronic components function properly and reliably. Typically, a finned metal heat dissipation device is attached to an outer surface of the electronic component to remove the heat therefrom. The heat absorbed by the heat dissipation device is then dissipated to ambient air.

However, as the operating speed of the electronic components has been continually upgraded, these kinds of conventional heat dissipation devices can no longer meet the heat dissipation requirements of modern electronic components.

What is needed, therefore, is a heat dissipation device which can overcome the above-described problems.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present heat dissipation device can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present heat dissipation device. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is an assembled, isometric view of a heat dissipation device in accordance with an exemplary embodiment of the disclosure.

FIG. 2 is an exploded view of the heat dissipation device of FIG. 1.

FIG. 3 is a cross sectional view of the heat dissipation device of FIG. 1, taken along a line III-III thereof.

FIG. 4 is an enlarged view of a part IV of FIG. 3.

FIG. 5 is an inverted, exploded view of the heat dissipation device of FIG. 1.

FIG. 6 is an inverted view of the heat dissipation device of FIG. 1.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, a heat dissipation device in accordance with an exemplary embodiment of the disclosure is used for dissipating heat generated by an electronic component (not shown) mounted on a printed circuit board (not shown). The heat dissipation device comprises a heat spreader 10 for thermally contacting the electronic component, and a fin set 20 disposed on the heat spreader 10. The heat spreader 10 is flat. In this embodiment, the heat spreader 10 is rectangular in shape. Four through holes 100 are defined at four corners of the heat spreader 10 for extension of four fasteners (not shown).

Referring to FIGS. 3 and 4 also, the heat spreader 10 comprises a base 11, a partition board 12 hermetically placed on the base 11, and a covering plate 13 hermetically placed on the partition board 12. The base 11 is made of metal with good heat conductivity, such as aluminum, copper, or alloys thereof. The base 11 has a rectangular profile. A central portion of the base 11 is recessed downwardly, thereby forming a first receiving portion 110 (as shown in FIG. 2). The partition board 12 seals the first receiving portion 110 to corporately form a first chamber 111 between the base 11 and the partition board 12. In use, the first chamber 111 is vacuum-exhausted, and accommodates working medium therein. The working medium is selected from a liquid which has a relatively low boiling point, such as water, methanol, and alcohol. A first wick structure 114 is formed on a total inner face of the central portion of the base 11 defining the first receiving portion 110. The first wick structure 114 is selected from some suitable materials, such as sintered metal powder, metal mesh, carbon nanotube array, and bundle of fibers. An empty zone 112 is defined below a periphery of the base 11 and surrounds the first chamber 111. The first chamber 111 is placed just above the electronic component. Besides the electronic component mounted on the printed circuit board, there are some other electronic components, so an area of the first chamber 111 is limited in a certain extent for avoiding interference with the other electronic components, and the other electronic components could be received in the empty zones 112.

Referring to FIGS. 5 and 6 also, the partition board 12 is a rectangular plate. The partition board 12 is made of metal with good heat conductivity, such as aluminum, copper, or alloys thereof. A second wick structure 120 is formed on a bottom face of the partition board 12 in the first chamber 111. The second wick structure 120 is selected from some suitable materials, such as sintered metal powder, metal mesh, carbon nanotube array, and bundle of fibers. When the partition board 12 is assembled on the base 11, an outer periphery of the second wick structure 120 is connected to the first wick structure 114. In other words, the first wick structure 114 cooperates with the second wick structure 120 to spread on a total inner face of the first chamber 111. A third wick structure 122 is formed on a top face of the partition board 12. The third wick structure 122 is selected from some suitable materials, such as sintered metal powder, metal mesh, carbon nanotube array, and bundle of fibers.

The covering plate 13 is made of metal with good heat conductivity, such as aluminum, copper, or alloys thereof. The covering plate 13 has a rectangular profile. A center portion of the covering plate 13 is protruded upwardly, thereby forming a second receiving portion 130. A periphery of the covering plate 13 is an annular frame 132 surrounding the second receiving portion 130 (as shown in FIG. 3). The frame 132 is hermetically attached on the partition board 12, whereby the covering plate 13 cooperates with the partition board 12 to define a second chamber 131 between the covering plate 13 and the partition board 12. In use, the second chamber 131 is vacuum-exhausted, and accommodates working medium therein. The working medium is selected from a liquid which has a relatively low boiling point, such as water, methanol, and alcohol. The second chamber 131 is located above the first chamber 111. The second chamber 131 is separated from the first chamber 111 by the partition board 12. A cross sectional area of the second chamber 131 is larger than that of the first chamber 111. A fourth wick structure 134 is formed on a total inner face of the second receiving portion 130. The fourth wick structure 134 is selected from some suitable materials, such as sintered metal powder, metal mesh, carbon nanotube array, and bundle of fibers. When the covering plate 13 is assembled on the partition board 12, an outer periphery of the fourth wick structure 134 is connected to the third wick structure 122. In other words, the third wick structure 122 cooperates with the fourth wick structure 134 to spread on a total inner face of the second chamber 131. The second chamber 131 is remote from the base 11 and is separated from the base 11 by the partition board 12.

The fin set 20 comprises a plurality of parallel fins 21. A passage (not labeled) is defined between every two adjacent fins 21 to allow airflow to flow therethrough. Each of the fins 21 comprises an upright sheet body and a pair of flanges bent horizontally from top and bottom of the sheet body and engaging the sheet body of an adjacent fin 21. The flanges at a bottom face of the fin set 20 thermally contact a top face of the covering plate 13. The fin set 20 occupies substantially the whole top face of the covering plate 13 except locations where the through holes 100 are located.

In use of the heat dissipation device, the base 11 of the heat spreader 10 thermally contacts and absorbs heat from the electronic component. The working medium in the first chamber 111 is heated and vapored upwardly to reach the partition board 12 of the heat spreader 10. At the partition board 12, the vapored working medium exchanges heat with the partition board 12 and then is condensed to liquid. The liquid refluences to the base 11 via the second wick structure 120 and the first wick structure 114. As heat accumulated in the partition board 12, the working medium in the second chamber 131 is heated and vapored upwardly to reach the covering plate 13 of the heat spreader 10. Then the vapored working medium exchanges heat with the covering plate 13 and then is condensed to liquid. The liquid refluences to the partition board 12 via the fourth wick structure 134 and the third wick structure 122. The vapored and condensed cycle continues, so heat absorbed by the heat spreader 10 is efficiently transferred to the fin set 20 placed on the covering plate 13 to be dissipated into ambient. Thus, heat dissipation efficiency of the heat dissipation device is greatly improved.

It is to be understood, however, that even though numerous characteristics and advantages of the present embodiment(s) have been set forth in the foregoing description, together with details of the structures and functions of the embodiment(s), the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.