HEAT SPREADER WITH A LIQUID-VAPOR SEPARATION STRUCTURE

Abstract

A heat spreader with a liquid-vapor separation structure includes a first panel, a second panel bonded with the first panel and defining therebetween an enclosed accommodation chamber, multiple spacer members arranged spaced apart from one another in the accommodation chamber and abutted between the first panel and the second panel and defining multiple vapor passages and liquid passages therebetween and dividing the accommodation chamber into a heat-absorbing zone and a condensing zone that are disposed in communication with each other through the vapor passages and the liquid passages, a first wick material partially disposed in the liquid passages and partially disposed in the heat-absorbing zone and the condensing zone, and a working fluid filled in the accommodation chamber.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to cooling technology and more particularly, to a heat spreader with a liquid-vapor separation structure.

2. Description of the Related Art

With the continuous growing trend of global electronics industry market, many electronic products (such as LED light module, computers and mobile phones, etc . . . ) have become an indispensable part of people's lives. However, with continuous development of these electronic products, in order to achieve enhanced product performance, the product composition units are easy to produce large amounts of heat during operation. When these product composition units have a certain degree of waste heat accumulated therein, the working efficiency of these electronic products will be lowered, or the lifespan of these electronic products will be shortened. Therefore, most electronic products have heat pipes or heat spreaders (vapor chambers) mounted in their heat-generating units and incorporated with radiation fins or cooling fans to form a cooling system for quick dissipation of waste heat. A heat pipe is one-dimensional and linear structure that transfers heat from one single point to another while a heat spreader (vapor chamber) is a plate that spreads heat from one point to a two-dimensional area. A heat spreader can rapidly and evenly spread out heat energy, accelerating thermal cycle efficiency. Therefore, heat spreaders (vapor chambers) have better thermal performance than heat pipes. Taiwan Patent Publication No. 1476361 discloses a heat spreader and the formation of the wick structure of the heat spreader. According to this design, the heat spreader comprises a bottom panel, a cover panel, a plurality of support projections, a wick structure and a working fluid. The cover panel is closed on the bottom panel and sealed such that an accommodation chamber is defined in between the cover panel and the bottom panel. The support projections are directly formed on the inner wall of the bottom panel or cover panel. The wick structure is coated on the surface of each support projection, the inside wall of the bottom panel and the inside wall of the cover panel. The working fluid is filled in the accommodation chamber to enhance the thermal conducting efficiency and speed of the heat spreader.

Although the heat spreader uses the support projections to enhance its supporting strength, the arrangement of the support projections makes the wick structure to exhibit an undulating configuration. During thermal cycling, the working fluid must go through apertures in the wick structure in between the support projections. This undulating structure will affect the reflux rate of the working fluid. Further, the working fluid flows in the accommodation chamber in a liquid-vapor coexistence manner. The flowing of the liquid phase and vapor phase of the working fluid in different directions may also cause a reduction in the mass flux during thermal cycling, further affecting the cooling effect.

Further, because the support projections of the aforesaid prior art heat transfer respectively consist of two solid semi-spheres of unequal radius and arranged spaced away from one another, if the heat spreader is mounted in a space that needs to bear a load or tends to be compressed, the stress point will be focused on the top side of the semi-spheres, thus, if the heat spreader is compressed, the pressure cannot be evenly distributed in all directions, leading to structural damage. Therefore, an improvement on the structural support of a heat spreader is desired.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a heat spreader with a liquid-vapor separation structure, which has multiple vapor passages and at least one liquid passage arranged therein to constrain the vapor phase and liquid phase of a working fluid to flow in different passages, increasing the mass flux of the working fluid in the vapor-liquid circulation system to achieve better heat dissipation performance.

It is another object of the present invention to provide a heat spreader with a liquid-vapor separation structure, which has multiple spacer members arranged therein and abutted between at least one first panel and a second panel thereof to form a strong support structure, achieving a better supporting effect.

To achieve these and other objects of the present invention, a heat spreader with a liquid-vapor separation structure comprises at least one first panel, a second panel, a plurality of spacer members, at least one piece of first wick, and a working fluid. The second panel bonded with the at least one first panel, defining with the at least one first panel at least one enclosed accommodation chamber therebetween. The spacer members are abutted between the at least one first panel and the second panel and arranged spaced apart from one another in the at least one enclosed accommodation chamber, defining a plurality of vapor passages and at least one liquid passage. The spacer members divide the at least one enclosed accommodation chamber into a heat-absorbing zone and condensing zone. The heat-absorbing zone and the condensing zone are disposed in communication with each other through the vapor passages and the at least one liquid passage. The at least one piece of first wick material has a part thereof disposed in the at least one liquid passage, and the other part thereof respectively disposed in the heat-absorbing zone and the condensing zone. The working fluid is filled in the at least one enclosed accommodation chamber.

Thus, the arrangement of the multiple vapor passages and the at least one liquid passage in the heat spreader effectively overcomes the problem of low mass flux of working fluid in the prior art designs due to vapor-liquid co-existence, achieving better working fluid cycle efficiency and enhancing heat dissipation performance.

Further, the spacer members are elongated members stopped between the first panel and the second panel. When compared to the support structure consisting of two solid semi-spheres of unequal radius of the prior art design, the invention provides a better supporting effect.

Other advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference signs denote like components of structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a heat spreader in accordance with a first embodiment of the present invention.

FIG. 2 is a front view of the first embodiment of the present invention, illustrating the internal structure of the heat spreader.

FIG. 3 is a longitudinal sectional view taken along line 3-3 of FIG. 2.

FIG. 4 is a cross sectional view of the heat spreader in accordance with the first embodiment of the present invention.

FIG. 5 is a front view illustrating the internal structure of a heat spreader in accordance with a second embodiment of the present invention.

FIG. 6 is a front view illustrating the internal structure of a heat spreader in accordance with a third embodiment of the present invention.

FIG. 7 is an exploded view of a part of the heat spreader in accordance with the third embodiment of the present invention.

FIG. 8 is a schematic side view of the heat spreader in accordance with the third embodiment of the present invention.

FIG. 9 is an exploded view of a heat spreader in accordance with a fourth embodiment of the present invention.

FIG. 10 illustrates cylindrical support blocks arranged in the heat-absorbing zone and the condensing zone of heat spreader in accordance with the fourth embodiment of the present invention.

FIG. 11 illustrates long columnar support blocks arranged in the heat-absorbing zone of heat spreader in accordance with the fourth embodiment of the present invention.

FIG. 12 illustrates long columnar support blocks arranged in the heat-absorbing zone and the condensing zone of heat spreader in accordance with the fourth embodiment of the present invention.

FIG. 13 is an exploded view of a heat spreader in accordance with a fifth embodiment of the present invention.

FIG. 14 is an exploded view of an alternate form of the heat spreader in accordance with the fifth embodiment of the present invention, illustrating the second wick material disposed in the second panel within the heat-absorbing zone.

FIG. 15 is an exploded view of another alternate form of the heat spreader in accordance with the fifth embodiment of the present invention, illustrating the second wick material disposed in the second panel within the heat-absorbing zone and the condensing zone.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-4, a heat spreader with a liquid-vapor separation structure in accordance with a first embodiment of the present invention is shown. The heat spreader 10 comprises at least one first panel 11, a second panel 12, a plurality of spacer members 13, at least one piece of first wick material 14 and a working fluid (not shown).

The at least one first panel 11 is bonded to the second panel 12. In this first embodiment, the number of the at least one first panel 11 is 1. Further, the first panel 11 and the second panel 12 define therebetween at least one enclosed accommodation chamber 121. In this first embodiment, the number of the at least one accommodation chamber 121 is 1. Further, at least one vapor discharge tube 19 is disposed in the connection area between the first panel 11 and the second panel 12. In this first embodiment, the number of the at least one vapor discharge tube 19 is 1. The vapor discharge tube 19 has one end thereof disposed in communication with the accommodation chamber 121, and an opposite end thereof extended out of the heat spreader 10 and blocked.

The multiple spacer members 13 are disposed inside the accommodation chamber 121 and abutted between the first panel 11 and the second panel 12. Further, the spacer members 13 are arranged spaced apart from one another, thereby defining a plurality of vapor passages 141 and at least one liquid passage 142. In this first embodiment, the number of the at least one liquid passage 142 is 2. Further, the multiple spacer members 13 device the accommodation chamber 121 into a heat-absorbing zone H and a condensing zone C. The heat-absorbing zone H and the condensing zone C are disposed in communication with each other by means of the multiple vapor passages 141 and the two liquid passages 142. Further, a heat-insulating zone A is defined in the accommodation chamber 121 between the heat-absorbing zone H and the condensing zone C. The multiple spacer members 13 are mounted in the heat-insulating zone A. In the present first embodiment of the present invention, the multiple spacer members 13 have an elongated shape; the multiple vapor passages 141 and the two liquid passages 142 respectively exhibit an elongated shape (see FIGS. 1, 2 and 4).

The at least one piece of first wick material 14 has a part thereof mounted in the two liquid passages 142. In this first embodiment of the present invention, the number of the at least one piece of first wick material 14 is 2. The other part of these two pieces of first wick material 14 is disposed in the heat-absorbing zone H and the condensing zone C. In this first embodiment of the present invention, these two pieces of first wick material 14 have an elongated shape. Further, these two pieces of first wick material 14 fill up the liquid passages 142. These two pieces of first wick material 14 can be fiber tows, copper powder or copper mesh (not shown). In this first embodiment of the present invention, these two pieces of first wick material 14 are fiber tows (see FIGS. 1 and 2)

The working fluid is filled in the accommodation chamber 121. Since technical filed of the working fluid is obvious to any person skilled in the art and difficult to display in the figure, it is unnecessary to repeat them here.

After understanding the structural details of this first embodiment of the present invention, the application of this first embodiment is explained hereinafter.

As illustrated in FIGS. 1-4, when the heat spreader 10 is at work, the heat-absorbing zone H transfers heat energy to the accommodation chamber 121, causing the working fluid in the two pieces of first wick material 14 to be vaporized into vapor phase. The working fluid will then go through the multiple vapor passages 141 in between the multiple spacer members 13 in the form of vapor phase, and then diffuses into the condensing zone C. When reached the condensing zone C, the working fluid can be reduced to liquid phase and adhered to the condensing zone C, and then guided by the two fiber tows of the first wick material 14 through the two liquid passages 142 between the condensing zone C and the heat-absorbing zone H to flow back to the heat-absorbing zone H. The multiple vapor passages 141 and the two liquid passages 142 constrain the vapor phase and liquid phase working fluid to flow in different passages, increasing the mass flux of the working fluid in the vapor-liquid circulation system. The multiple spacer members 13 are abutted between the first panel 11 and second panel 12 of the heat spreader 10 to form a sturdy support structure, achieving a better supporting effect. The use of the two elongated pieces of first wick material 14 in the heat spreader 10 effectively accelerates the circulation of the working fluid in the heat spreader 10. Physically, using fiber tows for the two pieces of first wick material 14 achieves more mass flux of the working fluid than that using sintered copper powder and copper mesh.

Accordingly, by the above-described first embodiment of the present invention, it is apparent that the arrangement of the multiple vapor passages 141 and the two liquid passages 142 in the heat spreader 10 effectively overcomes the problem of low mass flux of working fluid in the prior art designs due to vapor-liquid co-existence, achieving better working fluid cycle efficiency and enhancing heat dissipation performance.

As stated above, the multiple spacer members 13 are elongated members abutted between the first panel 11 and second panel 12 of the heat spreader 10. When compared to the support structure consisting of two solid semi-spheres of unequal radius of the prior art design, the invention provides a better supporting effect.

Referring to FIG. 5, a heat spreader 20 in accordance with a second embodiment of the present invention is shown. This second embodiment is substantially similar to the aforesaid first embodiment with the exceptions as follows:

The second panel 22 has a second wick material 28 sintered thereto. This second wick material 28 can be disposed in the second panel 22 within the heat-absorbing zone H2 and/or the condensing zone C2. In this second embodiment, the two pieces of first wick material 24 are disposed in contact with the second wick material 28.

The second wick material 28 can be selected from copper powder or copper mesh. In this second embodiment, the second wick material 28 is a copper mesh.

In this second embodiment, a respective certain area of the second wick material 28 is respectively sintered to the heat-absorbing zone H2 and the condensing zone C2 in the second panel 22 of the heat spreader 20, enabling the heat-absorbing zone H2 to have a relatively higher working fluid carrying capacity. Further, the second wick material 28 effectively and evenly carries the working fluid, enhancing the evapotranspiration efficiency of the working fluid. Further, the arrangement of the second wick material 28 in the condensing zone C2 inside the second panel 22 significantly increases the working fluid carrying capacity of the condensing zone C2, improving the reflux efficiency of the working fluid during cycling. The other structural features of this second embodiment and the effect this second embodiment can achieve are same as the aforesaid first embodiment, and thus, it is unnecessary to repeat them here.

Referring to FIGS. 6-8, a heat spreader 30 in accordance with a third embodiment of the present invention is shown. This third embodiment is substantially similar to the aforesaid first embodiment with the exceptions as follows:

The second panel 32 further comprises at least one recessed portion 322 located in the condensing zone C3. In this third embodiment, the number of the at least one recessed portion 322 is 2; the second panel 32 further has a third wick material 38 sintered thereto and located at a bottom side of each of the two recessed portion 322. Further, the third wick material 38 is connected with the first wick material 34. Further, the height of the two recessed portions 322 is greater than the height from the at least one first panel 31 to the second panel 32 (see FIG. 8). In this third embodiment, the number of the at least one first panel 31 is 2. These two first panels 31 are bonded to the second panel 32. Further, two enclosed accommodation chambers 321 are defined between the two first panels 31 and the second panel 32. Each accommodation chamber 321 has arranged therein a plurality of spacer members 33, a heat-absorbing zone H3, a condensing zone C3, a plurality of vapor passages 341, two liquid passages 342, two pieces of first wick material 38 and a working fluid (not shown).

The third wick material 38 can be selected from copper powder or copper mesh. In this third embodiment, the third wick material 38 is made from copper mesh.

In this third embodiment, the added structure of the two recessed portions 322 of the heat spreader 30 increase the working fluid storage capacity of the condensing zone C3; the two pieces of first wick material 34 are used to guide the working fluid from the condensing zone C3 back to the heat-absorbing zone H3. Further, changing the number of the component parts of the heat spreader 30 can relatively changing the cooling efficiency. The other structural features of this third embodiment and the effect this third embodiment can achieve are same as the aforesaid first embodiment, and thus, it is unnecessary to repeat them here.

Referring to FIG. 9, a heat spreader 40 in accordance with a fourth embodiment of the present invention is shown. This fourth embodiment is substantially similar to the aforesaid first embodiment with the exceptions as follows:

The second panel 42 further comprises a plurality of support blocks 49 corresponding to the heat-absorbing zone H4 and/or the condensing zone C4. In this fourth embodiment, the support blocks 49 are mounted in the second panel 42 within the heat-absorbing zone H4. Further, these support blocks 49 are cylindrical blocks. Further, the number of the at least one piece of first wick material 44 in this fourth embodiment is 4. These support blocks 49 are stopped against the first panel 41. Further, these support blocks 49 are respectively arranged at two opposite lateral sides of the first wick material 44 within the heat-absorbing zone H4 to keep the first wick material 44 in position. Further; the support blocks 49 can aligned with one another, or arranged in staggered rows. In this fourth embodiment, the support blocks 49 are aligned with one another. Further, the support blocks 49 are respectively arranged in alignment with the spacer members 43, forming a plurality of equally spaced support member sets 45. Further, except the aforesaid configuration, the support blocks 49 can also be arranged in the second panel 42 corresponding to the heat-absorbing zone H4 and the condensing zone C4 (see FIG. 10) and, the support blocks 49 can be configured to have a long columnar shape (see FIGS. 11 and 12).

In this fourth embodiment, the support blocks 49 of the heat spreader 40 can be arranged in the second panel 42 corresponding to the heat-absorbing zone H4 and/or the condensing zone C4 to effectively enhance the structural strength of heat spreader 40. The other structural features of this fourth embodiment and the effect this fourth embodiment can achieve are same as the aforesaid first embodiment, and thus, it is unnecessary to repeat them here.

Referring to FIG. 13, a heat spreader 50 in accordance with a fifth embodiment of the present invention is shown. This fifth embodiment is substantially similar to the aforesaid first embodiment with the exceptions as follows:

The second panel 52 has multiple support blocks 59 arranged therein corresponding to the heat-absorbing zone H5 and/or the condensing zone C5. In this fifth embodiment, the support blocks 59 are cylindrical blocks arranged in the second panel 52 within the heat-absorbing zone H5; the number of the at least one piece of first wick material 54 is 4. Further, the support blocks 59 are stopped against the first panel 51, and disposed at two opposite lateral sides of the multiple pieces of first wick material 54 within the heat-absorbing zone H5 to hold the multiple pieces of first wick material 54 in position. These support blocks 59 can aligned with one another, or arranged in staggered rows. In this fifth embodiment, the support blocks 59 are aligned with one another. Further, the support blocks 59 are respectively arranged in alignment with the spacer members 53, forming a plurality of equally spaced support member set 55.

Further, except the aforesaid configuration, the support blocks 59 can also be arranged in the second panel 52 corresponding to the heat-absorbing zone H5 and the condensing zone C5. Further, the support blocks 59 can be configured to have a long columnar shape (not shown).

The heat spreader 50 in accordance with this fifth embodiment of the present invention further comprises a second wick material 58 located in the second panel 52 corresponding to the heat-absorbing zone H5 and/or the condensing zone C5, and disposed in contact with the at least one piece of first wick material 54. In this fifth embodiment, the second wick material 58 is disposed in the second panel 52 within the condensing zone C5. Further, the number of the at least one piece of first wick material 54 is 4. Except the configuration described above, the second wick material 58 can be simply disposed in the second panel 52 within the condensing zone C5 (see FIG. 14). Alternatively, the second wick material 58 can be disposed in the second panel 52 within the heat-absorbing zone H5 and the condensing zone C5 (see FIG. 15).

The structural arrangement of this fifth embodiment significantly increases the working fluid carrying capacity of the heat-absorbing zone H5 and the condensing zone C5 while maintaining the structural strength of heat-absorbing zone H5 and condensing zone C5 of the heat spreader 50. The other structural features of this fifth embodiment and the effect this fifth embodiment can achieve are same as the aforesaid first embodiment, and thus, it is unnecessary to repeat them here.

Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.

Claims

1. A heat spreader, comprising:

at least one first panel;

a second panel bonded with said at least one first panel and defining with said at least one first panel at least one enclosed accommodation chamber therebetween;

a plurality of spacer members abutted between said at least one first panel and said second panel and arranged spaced apart from one another in said at least one enclosed accommodation chamber and defining a plurality of vapor passages and at least one liquid passage, said spacer members dividing said at least one enclosed accommodation chamber into a heat-absorbing zone and condensing zone, said heat-absorbing zone and said condensing zone being disposed in communication with each other through said vapor passages and said at least one liquid passage;

at least one piece of first wick material having a part thereof disposed in said at least one liquid passage and the other part thereof respectively disposed in said heat-absorbing zone and said condensing zone; and

a working fluid filled in said at least one enclosed accommodation chamber.

2. The heat spreader as claimed in claim 1, wherein said heat-absorbing zone and said condensing zone define a heat-insulating zone therebetween; said spacer members are disposed in said heat-insulating zone.

3. The heat spreader as claimed in claim 1, wherein said spacer members exhibit an elongated shape.

4. The heat spreader as claimed in claim 1, wherein said vapor passages and said at least one liquid passage respectively exhibit an elongated shape.

5. The heat spreader as claimed in claim 1, wherein said at least one piece of first wick material exhibits an elongated shape and fills up said at least one liquid passage.

6. The heat spreader as claimed in claim 1, further comprising at least one vapor discharge tube mounted in the bonding area between said at least one first panel and said second panel, said at least one vapor discharge tube each having one end thereof disposed in communication with said at least one enclosed accommodation chamber and an opposite end thereof extended out of the said heat spreader and blocked.

7. The heat spreader as claimed in claim 1, wherein said second panel has a plurality of support blocks mounted therein corresponding to said heat-absorbing zone and/or said condensing zone and abutted against said at least one first panel and disposed at two opposite lateral sides of said at least one first wick material to hold said at least one first wick material in position.

8. The heat spreader as claimed in claim 7, wherein said support blocks are optionally aligned with one another or arranged in staggered rows; said support block are respectively disposed in alignment with said spacer members, forming a plurality of support member sets.

9. The heat spreader as claimed in claim 7, wherein said second panel further comprises a second wick material sintered thereto, said second wick material being disposed in said heat-absorbing zone and/or said condensing zone and kept in contact with said at least one piece of first wick material.

10. The heat spreader as claimed in claim 1, wherein said second panel further comprises at least one recessed portion disposed within said condensing zone, and a third wick material sintered to a bottom side of each said recessed portion and connected with said first wick material, the height of said at least one recessed portion being greater than the height from said at least one first panel to said second panel.

11. The heat spreader as claimed in claim 1, wherein said at least one first wick material is selected from the material group of fiber tow, copper powder and mesh.