TWO-PHASE FLOW HEAT DISSIPATION PLATE STRUCTURE FORMED BY STAMPING AND FORGING

Description

This application claims the priority benefit of Taiwan patent application number 113148189 filed on Dec. 11, 2024, the disclosure of which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a two-phase flow heat dissipation plate structure, and more particularly, to a two-phase flow heat dissipation plate structure formed by stamping and forging to have increased thermal contact areas and accordingly, effectively improved heat dissipation efficiency.

BACKGROUND OF THE INVENTION

Conventionally, the vapor chamber in an electronic product is attached to the surface of a heat producing element, such as a central processing unit, a graphics processing unit, or a single chip microcomputer. The conventional vapor chamber has an upper plate member and a lower plate member, which together define a chamber between them. The chamber is internally filled with a working fluid and provided with a wick structure. An outer central area of the lower plate member is in contact with a heat producing element. When the heat produced by the heat producing element is absorbed by the lower plate member of the vapor chamber, the working fluid in the vapor chamber is heated and transited to a gas state. When the gas-state working fluid flows upward to the upper plate member and releases the absorbed heat, the gas-state working fluid is condensed to thereby carry away the heat produced by the heat producing element to achieve the purpose of heat dissipation.

The processes of manufacturing the upper and the lower plate member of the conventional vapor chamber generally include two types, namely, stamping and forging. In the case of forging, a relatively thick metal copper sheet of 4 mm, for example, is forged to shape the upper and the lower plate member. Since the copper sheet is relatively thick, a large pressure is required to complete the forging process. However, the upper and lower plate members forged with large pressure have the problems of non-uniform thickness at different locations of the plate members and expansive manufacturing cost. Owing to these problems in the forging process, most manufacturers would select the manufacturing process of single stamping to form the plate members of the vapor chamber. Stamping can be applied to a relatively thin metal copper sheet of 1 mm, for example. And, the upper and lower plate member formed by stamping can have uniform thickness at all locations and low manufacturing cost.

However, the plate members of the conventional vapor chamber manufactured by stamping have another problem, i.e. the upper and the lower plate member all have inner and outer sides as smooth and flat surfaces. The outer side of the lower plate member is in contact with a heat producing element, such as a chip or a processing unit having high thermal flux density. A core point (or hot point) will occur in the heat producing element when the same operates. The occurrence of core or hot point would result in overheat at a local area such as a central area of the heat producing element. Since the lower plate member has an inner side being a smooth and flat surface that has very limited unit areas, the thermal contact areas in the conventional vapor chamber between the working fluid and the inner side of the lower plate member are limited and relatively small, and the working fluid is heated and vaporized at a slow speed to result in poor evaporation efficiency. Therefore, the conventional vapor chamber can no longer provide quick heat dissipation and good heat dissipation effect for the current single-chip microcomputer or processing unit having high thermal flux density, and the heat producing elements have reduced service life and are subjected to damage easily.

It is therefore tried by the inventor to develop an improved heat dissipation plate structure in an attempt to solve the problem often found in the heat producing element with high heat flux density, i.e. the produced heat could not be quickly dissipated from a core point of the heat producing element.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a two-phase flow heat dissipation plate structure, which is formed by stamping and forging to increase its thermal contact areas with a working fluid, so as to provide effectively upgraded heat exchange performance.

Another object of the present invention is to provide a two-phase flow heat dissipation plate structure formed by stamping and forging to achieve the purpose of reduced manufacturing cost.

To achieve the above and other objects, the two-phase flow heat dissipation plate structure formed by stamping and forging according to the present invention includes a plate member formed of a stamped metal sheet and having a plate upper side and a plate lower side. The plate upper side defines a receiving space that is recessed toward the plate lower side, and the receiving space has a heat source contact area provided at a predetermined location thereof. The heat source contact area is processed by forging to form a plurality of convex and concave microstructure. And, the microstructures may be formed on the plate upper side or the plate lower side or at least one of the plate upper and lower sides.

With the present invention, the microstructures in the heat source contact area of the plate member can provide increased heat dissipation areas and accordingly provide more thermal contact areas for contacting with a working fluid to speed up the evaporation efficiency of the working fluid and effectively upgrade the heat exchange performance while reduce the manufacturing cost.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein

FIG. 1 is an exploded perspective view of a two-phase flow heat dissipation plate structure according to a preferred embodiment of the present invention;

FIG. 2 is a fragmentary and enlarged view showing another type of microstructure formed on the two-phase flow heat dissipation plate structure according to the preferred embodiment of the present invention;

FIG. 3 is a fragmentary top view of a heat source contact area in the two-phase flow heat dissipation plate structure of FIG. 1; and

FIG. 4 is an assembled sectional side view of the two-phase flow heat dissipation plate structure according to the preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described with some preferred embodiments thereof.

Please refer to FIGS. 1, 3, and 4. A two-phase flow heat dissipation plate structure 1 formed by stamping and forging according to a preferred embodiment of the present invention can be applied to a two-phase flow heat dissipation unit 2, such as a vapor chamber, a flat heat pipe, or a heat spreader. The two-phase flow heat dissipation plate structure 1 includes a plate member 11 formed of a stamped metal sheet, such as a copper sheet, a commercially pure titanium sheet, an aluminum sheet, or other metal sheets. The plate member 11 can be used as an upper plate member and/or a lower plate member of the two-phase flow heat dissipation unit 2, such as a vapor chamber. Specifically, the plate member 11 in the preferred embodiment of the present invention is formed of a copper sheet, which is stamped to have a complete configuration and shape of an upper or a lower plate member of the vapor chamber.

The stamped plate member 11 has a plate upper side 111 and a plate lower side 113. The plate upper side 111 is provided with a receiving space 112 that is recessed toward the plate lower side 113; and at least one heat source contact area 12 is provided in the receiving space 112 at a predetermined location for fitly contacting with a corresponding heat source 3, such as a central processing unit, a graphics processing unit, or a single-chip microcomputer that has high heat flux density. Specifically, a surface of the plate lower side 113 of the plate member 11 below the heat source contact area 12 is in contact with a surface of the heat source 3 for absorbing heat produced by the heat source 3.

Please refer to FIGS. 1 and 2. The heat source contact area 12 includes a plurality of protruded (convex) or recessed (concave) microstructures 13 formed by forging. The microstructures 13 are densely distributed over the plate upper side 111 or the plate lower side 113 within the heat source contact area 12. In other words, the microstructures 13 in the heat source contact area 12 include a plurality of convex polyhedrons, such as blocks and columns as shown in FIG. 1, and/or a plurality of concave polyhedrons, such as holes, cavities and pits as shown in FIG. 2, which are directly formed on the plate upper side 111 or the plate lower side 113 of the plate member 11 by way of forging. The microstructures 13 may be shaped as cuboids (as shown in FIG. 3), polyhedrons, elongated strips, grids, regular or irregular three-dimensional shapes.

In FIGS. 1 and 3, the microstructures 13 are configured as a plurality of rows of cuboids, which are formed by forging to be parallelly closely spaced on the plate upper side 111 of the plate member 11, such that a plurality of convex polyhedrons (such as blocks or columns) is protruded from the plate upper side 111 of the plate member 11 within the heat source contact area 12. Every microstructure 13 has an outer surface consisting of a plurality of heat dissipation surfaces 131. Therefore, hundreds and thousands of microstructures 13 each having a plurality of heat dissipation surfaces 131 are densely provided in the heat source contact area 12, and every one unit of area of the plate member 11 in the heat source contact area 12 has largely increased thermal contact areas with a working fluid to speed up the evaporation of the working fluid and increase the vaporization efficiency.

Please refer to FIGS. 1 and 4. The plate member 11 can be covered and sealed to another metal plate member to form the two-phase flow heat dissipation unit 2. In the present invention, the plate member 11 forms a lower plate member of the two-phase flow heat dissipation unit 2, while the other plate metal plate member forms an upper plate member 25 of the two-phase flow heat dissipation unit 2. However, it is understood the present invention is not necessarily limited to the above embodiment. The upper plate member 25 is assembled to a top of the recessed receiving space 112 formed on the plate member 11 (i.e. the lower plate member of the two-phase flow heat dissipation unit 2), such that a chamber 21 is defined between the plate member 11 and the upper plate member 25. A working fluid is filled in the chamber 21 and a wick structure 22 is provided on an inner wall surface of the chamber 21. The wick structure 22 can be a plurality of grooves, a sintered powder layer, metal woven meshes (such as copper meshes), or any combination thereof. Further, the wick structure can be selectively provided on an inner surface of the upper plate member 25 and/or the lower plate member 11 of the chamber 21. In the preferred embodiment of the present invention, the wick structure 22 is formed on the inner wall surface of the plate member 11 (i.e. the plate upper side 111 of the plate member 11), on the heat dissipation surfaces 131 of all the microstructures 13, and on the inner wall surface of the upper plate member 25.

An outer wall surface (i.e. the plate lower side 113) of the plate member 11 of the two-phase flow heat dissipation unit 2 is in contact with the heat source 3, and the inner wall surface (i.e. the plate upper side 111) of the plate member 11 within the heat source contact area 12 forms an evaporation surface 23, while the inner wall surface of the upper plate member 25 forms a condensation surface 24. When the evaporation surface 23 of the two-phase flow heat dissipation unit 2 absorbs heat produced by the heat source 3, such as a central processing unit or a chip that has high heat flux density, the heat dissipation surfaces 131 of the microstructures 13 on the evaporation surface 23 exchange heats with the working fluid quickly to speed up the evaporation of the working fluid, causing dramatic phase transition of the working fluid in the two-phase flow heat dissipation unit 2. The quickly heated working fluid is transited from a liquid state to a gas state to flow toward the condensation surface 24 until the gas-state working fluid is condensed to a liquid state again on the upper plate member 25. The condensed working fluid then flows back to the evaporation surface 23 under gravity force in addition to capillary force provided by the wick structure 22. The phase transition of the working fluid between the liquid state and the gas state continues and repeats to achieve the effect of heat dissipation.

According to the present invention, the two-phase flow heat dissipation plate structure 1 is first shaped by stamping and then further provided in the heat source contact area 12 of the two-phase flow heat dissipation plate structure 1 with the microstructures 13 by forging. The microstructures 13 provide more thermal contact areas for contacting with the working fluid to thereby enable faster evaporation of the working fluid and accordingly effectively enhanced heat exchanging efficiency and reduced manufacturing cost. Besides, when the two-phase flow heat dissipation plate structure 1 of the present invention is used to form a two-phase flow heat dissipation unit 2 for dissipating the heat produced by the heat source 3 with high thermal flux density, the two-phase flow phase transition of the working fluid in the chamber 21 of the two-phase flow heat dissipation unit 2 is effectively sped up to thereby effectively upgrade the heat transfer performance of the two-phase flow heat dissipation unit 2.

The present invention has been described with a preferred embodiment thereof and it is understood that many changes and modifications in the described embodiment can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.