Vapor chamber structure with improved wick and method for manufacturing the same
A vapor chamber structure includes a casing, a working fluid, and an improved wick layer. The casing has an airtight vacuum chamber. The working fluid is filled into the airtight vacuum chamber. The wick layer is formed on a surface of the airtight vacuum chamber. Therefore, the present invention can increase the backflow velocity of the working fluid and improve the boiling of the working fluid due to the match of the improved wick structure. Because the backflow velocity and boiling of the working fluid is increased, the heat-transmitting efficiency is increased.
1. Field of the Invention
The present invention relates to a vapor chamber structure and a method for manufacturing the same, and particularly relates to a vapor chamber structure having an improved wick and a method for manufacturing the same.
2. Description of the Related Art
Cooling or heat removal has been one of the major obstacles of the electronic industry. The heat dissipation increases with the scale of integration, the demand for higher performance, and the increase of multi-functional applications. The development of high performance heat transfer devices becomes one of the major development efforts of the industry.
A heat sink is often used for removing the heat from the device or from the system to the ambient. The performance of a heat sink is characterized by the thermal resistance with a lower value representing a higher performance level. This thermal resistance generally consists of the heat-spreading resistance within the heat sink and the convective resistance between the heat sink surface and the ambient environment. To minimize the heat-spreading resistance, highly conductive materials, e.g. copper and aluminum, are typically used to make the heat sink. However, this conductive heat transfer through solid materials is generally insufficient to meet the higher cooling requirements of newer electronic devices. Thus, more efficient mechanisms have been developed and evaluated, and the vapor chamber has been one of those commonly considered mechanisms.
Vapor chambers make use of the heat pipe principle in which heat is carried by the evaporated working fluid and is spread by the vapor flow. The vapor eventually condenses over the cool surfaces, and, as a result, the heat is distributed from the evaporation surface (the interface with the heat source) to the condensation surfaces (the cooling surfaces). If the area of the cooling surfaces is much higher than the evaporating surface, the spreading of heat can be achieved effectively since the phase change (liquid-vapor-liquid) mechanism occurs near isothermal conditions.
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In the prior art, the chamber 9 uses only a simple wick structure 91 to return the condensed fluid by capillary force and to help initiate boiling of the working fluid. A simple wick structure is difficult to optimize for both boiling initiation and fluid flow by capillary force and thus the overall thermal performance of the vapor chamber is limited.
Furthermore the backflow efficiency (ability to return the working fluid to the evaporator portion of the vapor chamber) of the working fluid is limited.
SUMMARY OF THE INVENTIONOne particular aspect of the present invention is to provide a vapor chamber structure and a method for manufacturing the same. The vapor chamber structure of the present invention has improved thermal performance due to the usage of at least one improved wick structure.
In order to achieve the above-mentioned aspects, the present invention provides a vapor chamber structure, comprising: a casing, a working fluid, and one or more improved wick layers or backflow accelerating bodies. The casing has an airtight vacuum chamber. The working fluid is filled into the airtight vacuum chamber. The wick layer is formed on a surface of the airtight vacuum chamber.
In order to achieve the above-mentioned aspects, the present invention provides a method for manufacturing a vapor chamber structure, comprising: providing a casing that is composed of one or more upper casings and one or more lower casings; forming one or more improved wicks on an internal surface of the casing; assembling the upper casing(s) and the lower casing(s) together to form a receiving chamber; pumping away air from the receiving chamber to form an airtight vacuum chamber; and then filling a working fluid into the airtight vacuum chamber and sealing the casing.
Therefore, the present invention can improve the thermal performance of the vapor chamber due to the use of the improved wick structures.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. Other advantages and features of the invention will be apparent from the following description, drawings and claims.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings, in which:
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The casing 10 has an airtight vacuum chamber 100, and the working fluid 20 is filled into the airtight vacuum chamber 100. The casing 10 is composed of an upper casing 101 and a lower casing 102 that mates with the upper casing 101. Moreover, the casing 10 has contact surfaces between the upper casing 101 and the lower casing 102. The contact surfaces have a predetermined width, in order to assemble the upper casing 101 and the lower casing 102 easily.
Furthermore, the vapor chamber structure further comprises at least one filling pipe 15 communicated with the airtight vacuum chamber 100 via a joint opening 103 of the casing 10 (in
In order to increase the matching between the filling pipe 15 and the joint opening 103 of the casing 10, a contact surface between the casing 10 and the filling pipe 15 has a length L larger than a double length of a diameter D of the filling pipe 15 (L>2D as shown in
The wick layer 12 is formed on an internal surface of the airtight vacuum chamber 100. The wick layer 12 is made of metal powders via a sintering method, or is composed of metal meshes or micro grooves or other materials or geometries that are conducive to enhancing the flow of the working fluid due to capillary forces. Another function of the wick structure is to promote and enhance boiling of the working fluid adjacent to the heat input areas.
The structure strengthening bodies 13 are respectively arranged in the airtight vacuum chamber 100 and between the upper casing 101 and the lower casing 102 for supporting the casing 10. In the first embodiment, each structure strengthening body 13 can be a solid post, made of copper or any solid material with high thermal conductivity and high strength. Moreover, the structure strengthening bodies 13 are concentrated in a center position (the position of the casing 10 is fragile and is deformed easily) of the airtight vacuum chamber 100. Hence, although the casing 10 is pressed inward during a vacuum-pumping process, the casing 10 can still maintain its surface planarization on a top surface and a bottom surface thereof due to the support of the structure strengthening bodies 13. Therefore, the casing 10 can compactly contact with a heat-generating source (not shown) for increasing heat-transmitting effect between the heat-generating source and the vapor chamber structure la.
In the same principle, because the vapor chamber structure 1a always needs to perform heat-absorbing action and heat-releasing action, the casing 10 expands when hot and shrinks when cold. However, in the present invention, the casing 10 can still maintain its surface planarization on the top surface and the bottom surface thereof due to the support of the structure strengthening bodies 13.
Furthermore, the vapor chamber structure 1a comprises at least one backflow accelerating body 14. The backflow accelerating bodies 14 are respectively arranged in the airtight vacuum chamber 100 and between the upper casing 101 and the lower casing 102 for increasing the backflow velocity of the working fluid 20 because that each backflow accelerating body 14 is a flow path for the backflow of the working fluid 20 (as shown in
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The method further comprises assembling the upper casing 101 and the lower casing 102 together to form a receiving chamber (S104); pumping away air from the receiving chamber to form an airtight vacuum chamber 100 (S105) and then filling a working fluid 20 into the airtight vacuum chamber 100 and sealing the casing 10 (S106).
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Although the present invention has been described with reference to the preferred best methods thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have been suggested in the foregoing description, and others will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.
Claims
1. A vapor chamber structure, comprising:
- a casing having an upper casing and a lower casing to form an airtight vacuum chamber;
- a working fluid filled into the airtight vacuum chamber;
- and an improved wick layer formed on an internal surface of the airtight vacuum chamber.
2. The vapor chamber structure as claimed in claim 1, wherein the improved wick layer is in a discontinuous fashion and at least one separated portion of the wick is disposed to isolate the wick layer.
3. The vapor chamber structure as claimed in claim 1, further comprising at least one structure strengthening body arranged in the airtight vacuum chamber for supporting the upper casing and the lower casing.
4. The vapor chamber structure as claimed in claim 3, wherein one or more structure strengthening bodies has a solid post and a wick layer circumferentially covering an external surface of the solid post.
5. The vapor chamber structure as claimed in claim 1, wherein one or more backflow accelerating bodies has a wick post and a metal solid layer covered circumferentially on an external surface of the wick post.
6. The vapor chamber structure as claimed in claim 1, wherein at least one channel and at least one micro-channel are disposed on the casing.
7. The vapor chamber structure as claimed in claim 6, wherein a width of each channel is greater than 200 microns and a width of each micro-channel is smaller than 200 microns.
8. The vapor chamber structure as claimed in claim 1, wherein at least one channel is disposed on the lower casing, the improved wick layer comprises a first wick layer formed by a first wick element contacting the upper casing and a second wick layer formed by a second wick element contacting the lower casing.
9. The vapor chamber structure as claimed in claim 8, wherein a size of the second wick element is different from a size of the first wick element.
10. The vapor chamber structure as claimed in claim 8, wherein each channel is filled by the first wick element.
11. The vapor chamber structure as claimed in claim 1, wherein the thickness of the improved wick layer is variable depending on a travel path of the working fluid.
12. The vapor chamber structure as claimed in claim 11, wherein the thickness of a central portion of the improved wick layer disposed on the upper casing is thinner than the thickness of a peripheral portion.
13. The vapor chamber structure as claimed in claim 12, wherein at least one micro-channel is formed on the improved wick layer disposed on the upper casing.
14. The vapor chamber structure as claimed in claim 11, wherein the thickness of a central portion of the improved wick layer disposed on the lower casing is thicker than the thickness of a peripheral portion.
15. The vapor chamber structure as claimed in claim 14, wherein at least one micro-channel is formed on the improved wick layer disposed on the lower casing.
16. The vapor chamber structure as claimed in claim 1, wherein the improved wick has at least one wick layer formed by second wick elements are respectively placed in predetermined patches in the wick layer formed by first wick elements.
17. The vapor chamber structure as claimed in claim 16, wherein each wick layer formed by second wick elements are placed in an isolated patch in the wick layer formed by first wick elements.
18. The vapor chamber structure as claimed in claim 16, wherein the wick layer formed by second wick elements has interdigitated portions with respect to the first wick layer in a plan direction.
19. The vapor chamber structure as claimed in claim 16, wherein the wick layer formed by second wick elements has interdigitated portions with respect to the first wick layer in a height direction.
20. The vapor chamber structure as claimed in claim 16, wherein the wick layer formed by second wick elements has radial portions in a plan direction.
21. The vapor chamber structure as claimed in claim 16, wherein the wick layer formed by second wick elements has circular portions in a plan direction.
22. The vapor chamber structure as claimed in claim 1, wherein the improved wick layer comprises wick elements having at least two sizes.
23. The vapor chamber structure as claimed in claim 22, wherein the wick elements having different sizes are arranged in a continuous gradient or step-wise gradient of element sizes to form into the wick layer.
24. The vapor chamber structure as claimed in claim 22, wherein the improved wick layer is a wick structure formed by a plurality of wick clusters and each wick cluster is formed by combining wick elements having different sizes with each other.
25. The vapor chamber structure as claimed in claim 22, wherein the wick layer is formed by stacking the wick elements upon each other in decreasing sizes with the largest wick elements on the bottom.
26. The vapor chamber structure as claimed in claim 22, wherein the wick layer is formed by stacking the wick elements upon each other in increasing sizes with the smallest wick elements on the bottom.
27. The vapor chamber structure as claimed in claim 1, wherein each exterior surface of one or more of the wick elements has a coated layer.
28. The vapor chamber structure as claimed in claim 1, wherein at least one portion of the wick layer comprises a multi-layered wick layer formed by stacking at least one first wick layer and at least one second wick layer upon each other layer with the first wick layer on the bottom.
29. The vapor chamber structure as claimed in claim 28, wherein the second wick layer between two first layers in the multi-layered wick layer is separated into at least one isolated portion.
30. The vapor chamber structure as claimed in claim 1, wherein wick elements of the wick layer completely fill the airtight vacuum chamber.
31. The vapor chamber structure as claimed in claim 30, wherein at least one second wick layer formed by second wick elements are embedded inside the chamber to form a multi-layered structure.
32. The vapor chamber structure as claimed in claim 1, wherein at least one protrusion with predetermined height extends from the casing forming an extended surface and each extended surface is coated with the wick layer.
33. The vapor chamber structure as claimed in claim 1, wherein at least one depression is disposed on the casing forming an extended surface and each extended surface is coated with the wick layer.
34. The vapor chamber structure as claimed in claim 1, further comprising at least one filling pipe communicated with the airtight vacuum chamber via a joint opening of the casing.
35. The vapor chamber structure as claimed in claim 1, wherein the length of the filling pipe is larger than a double length of a diameter of the filling pipe.
36. The vapor chamber as claimed in claim 1, wherein the wick layer is pre-fabricated outside of and free from the casing, and is subsequently affixed to the interior of the casing.
37. The vapor chamber structure as claimed in claim 36, wherein the wick layer is in a discontinuous fashion and at least one separated portion of the wick is disposed to isolate the wick layer.
38. The vapor chamber structure as claimed in claim 36, further comprising at least one structure strengthening body arranged in the wick for supporting the upper casing and the lower casing.
39. The vapor chamber structure as claimed in claim 36, wherein one or more structure strengthening bodies has a solid post and a wick layer circumferentially covering an external surface of the solid post.
40. The vapor chamber structure as claimed in claim 36, wherein one or more backflow accelerating bodies has a wick post and a metal solid layer covered circumferentially on an external surface of the wick post.
41. The vapor chamber structure as claimed in claim 36, wherein at least one channel and at least one micro-channel are disposed on the casing.
42. The vapor chamber structure as claimed in claim 41, wherein a width of each channel is greater than 200 microns and a width of each micro-channel is smaller than 200 microns.
43. The vapor chamber structure as claimed in claim 36, wherein at least one channel is disposed on the lower casing, the wick layer comprises a first wick layer formed by a first wick element contacting the upper casing and a second wick layer formed by a second wick element contacting the lower casing.
44. The vapor chamber structure as claimed in claim 43, wherein a size of the second wick element is different from a size of the first wick element.
45. The vapor chamber structure as claimed in claim 43, wherein each channel is filled by the first wick element.
46. The vapor chamber structure as claimed in claim 36, wherein the thickness of the wick layer is variable depending on a travel path of the working fluid.
47. The vapor chamber structure as claimed in claim 46, wherein the thickness of a central portion of the wick layer disposed on the upper casing is thinner than the thickness of a peripheral portion.
48. The vapor chamber structure as claimed in claim 47, wherein at least one micro-channel is formed on the wick layer disposed on the upper casing.
49. The vapor chamber structure as claimed in claim 46, wherein the thickness of a central portion of the wick layer disposed on the lower casing is thicker than the thickness of a peripheral portion.
50. The vapor chamber structure as claimed in claim 49, wherein at least one micro-channel is formed on the wick layer disposed on the lower casing.
51. The vapor chamber structure as claimed in claim 36, wherein at least one wick layer formed by second wick elements are respectively placed in predetermined patches in the wick layer formed by first wick elements.
52. The vapor chamber structure as claimed in claim 51, wherein each wick layer formed by second wick elements are placed in an isolated patch in the wick layer formed by first wick elements.
53. The vapor chamber structure as claimed in claim 51, wherein the wick layer formed by second wick elements has interdigitated portions with respect to the first wick layer in a plan direction.
54. The vapor chamber structure as claimed in claim 51, wherein the wick layer formed by second wick elements has interdigitated portions with respect to the first wick layer in a height direction.
55. The vapor chamber structure as claimed in claim 51, wherein the wick layer formed by second wick elements has radial portions in a plan direction.
56. The vapor chamber structure as claimed in claim 51, wherein the wick layer formed by second wick elements has circular portions in a plan direction.
57. The vapor chamber structure as claimed in claim 36, wherein the wick layer comprises wick elements having at least two sizes.
58. The vapor chamber structure as claimed in claim 57, wherein the wick elements having different sizes are arranged in a continuous gradient or step-wise gradient of wick element sizes to form into the wick layer.
59. The vapor chamber structure as claimed in claim 57, wherein the wick layer is a wick structure formed by a plurality of wick clusters and each wick cluster is formed by combining wick elements having different sizes with each other.
60. The vapor chamber structure as claimed in claim 57, wherein the wick layer is formed by stacking the wick elements upon each other in decreasing sizes with the largest wick elements on the bottom.
61. The vapor chamber structure as claimed in claim 57, wherein the wick layer is formed by stacking the wick elements upon each other in increasing sizes with the smallest wick elements on the bottom.
62. The vapor chamber structure as claimed in claim 36, wherein each exterior surface of one or more of the wick elements has a coated layer.
63. The vapor chamber structure as claimed in claim 36, wherein at least one portion of the wick layer comprises a multi-layered wick layer formed by stacking at least one first wick layer and at least one second wick layer upon each other layer with the first wick layer on the bottom.
64. The vapor chamber structure as claimed in claim 63, wherein the second wick layer between two first layers in the multi-layered wick layer is separated into at least one isolated portion.
65. The vapor chamber structure as claimed in claim 36, wherein wick elements of the wick layer completely fill the airtight vacuum chamber.
66. The vapor chamber structure as claimed in claim 65, wherein at least one second wick layer formed by second wick elements are embedded inside the wick to form a multi-layered structure.
67. The vapor chamber structure as claimed in claim 36, wherein at least one protrusion with predetermined height extends from the casing forming an extended surface and each extended surface is coated with the wick layer.
68. The vapor chamber structure as claimed in claim 36, wherein at least one depression is disposed on the casing forming an extended surface and each extended surface is coated with the wick layer.
69. The vapor chamber structure as claimed in claim 36, further comprising at least one filling pipe communicated with the airtight vacuum chamber via a joint opening of the casing.
70. The vapor chamber structure as claimed in claim 36, wherein the length of the filling pipe is larger than a double length of a diameter of the filling pipe.
71. A method for manufacturing a vapor chamber structure, comprising:
- providing a casing composed of an upper casing and a lower casing;
- forming a wick layer on an internal surface of the casing;
- assembling the upper casing and the lower casing together to form a chamber;
- pumping away air from the chamber; and
- filling a working fluid into the chamber and sealing the casing.
72. The method for manufacturing a vapor chamber structure as claimed in claim 71, wherein a plurality of structures are arranged between the upper casing and the lower casing and comprise at least one backflow accelerating body, or at least one channel, or at least one micro-channel, or a multi-layered wick layer.
73. A method for manufacturing a vapor chamber structure, comprising:
- providing a casing composed of an upper casing and a lower casing;
- pre-fabricating a wick layer outside of and free from the casing, and subsequently affixing the wick layer to the interior of the casing;
- assembling the upper casing and the lower casing together to form a chamber;
- pumping away air from the chamber; and
- filling a working fluid into the chamber and sealing the casing.
74. The method for manufacturing a vapor chamber structure as claimed in claim 73, wherein a plurality of structures are arranged between the upper casing and the lower casing and comprise at least one backflow accelerating body, or at least one channel, or at least one micro-channel, or a multi-layered wick layer.
75. The method for manufacturing a pre-fabricated improved wick outside and apart from the vapor chamber, such wick layer formed by a plurality of wick elements adjoined to each other such that they create a continuous, porous layer.
76. The method as claimed in claim 75 wherein the joining method for the wick elements is by a high temperature process over 350 degrees Celsius.
77. The method as claimed in claim 76 wherein the joining method is chosen from sintering, diffusion bonding, copper-copper oxide eutectic bonding, or brazing.
78. The method as claimed in claim 75 wherein the method reduces the wick layer thickness in certain locations.
79. The method as claimed in claim 78 wherein wick elements are reduced in number or eliminated in those areas of reduced wick layer thickness.
80. The method as claimed in claim 79 wherein adjoined wick elements are compressed in those areas of reduced wick layer thickness.
81. The method as claimed in claim 75 wherein the method increases the wick layer thickness in certain locations.
82. The method as claimed in claim 81 wherein wick elements are increased in number in those areas of increased wick layer thickness.
83. The method as claimed in claim 75 wherein the method includes the addition of structure strengthening bodies to the wick layer in certain locations.
84. The method as claimed in claim 75 wherein the method includes the addition of backflow accelerating bodies to the wick layer in certain locations.
85. The method as claimed in claim 75 wherein the method includes bending or forming the wick layer in certain locations.
86. The method as claimed in claim 75 wherein the method includes the use of wick elements of different sizes or types.
87. The method as claimed in claim 86 wherein the method includes arranging certain of the wick elements by size or type within certain areas of the wick.
88. The method as claimed in claim 87 wherein the method arranges wick elements by size in the vertical direction with either the smallest elements on top or conversely with the largest elements on top to form a piece-wise continuous or continuous gradient of wick element sizes.
89. The method as claimed in claim 87 wherein the method arranges wick elements by size in the plan or horizontal direction from elements of smaller to larger size to form a piece-wise continuous or continuous gradient of wick element sizes.
90. The method as claimed in claim 87 wherein the method arranges wick elements of different sizes or types in multiple layers, with at least one layer of one size or type of wick element and another layer of a second size or type of wick element.
91. The method as claimed in claim 90 wherein the method arranges wick elements of different sizes or types in multiple layers, with at least one layer of one size or type of wick element and another layer of a second size or type of wick element, and also provides communication or a via in certain locations from a first wick layer to a third wick layer through an intervening second wick layer.
92. The method as claimed in claim 87 wherein the method arranges wick elements of different sizes or types such that one or more patches of a wick element of one size or type are arranged within a field of substantially a wick element of a second size or type.
93. The method as claimed in claim 92 wherein the method arranges wick elements of different sizes or types such that more than one patches of a wick element of one size or type are arranged within a field of substantially a wick element of a second size or type, and there is a communication between the wick elements of the first size or type.
94. The method as claimed in claim 93 wherein the method provides communication between patches by creating pathways between patches of the same wick element that forms the patches.
95. The method as claimed in claim 93 wherein the method provides communication between patches by using wick elements of a third type or by no wick elements at all to create the communication pathways, as distinguished from using the first wick elements or the second wick elements.
96. The method as claimed in claim 87 wherein the method arranges wick elements of different sizes or types both in multiple layers and with patches of wick elements of different sizes or types within a field comprised of wick elements of a different size or type within certain layers, and providing for communication between patches within layers horizontally and for communication between layers vertically, such method consisting of the structured arrangement of wick elements of different sizes or types in certain locations starting with a first layer and subsequently adding additional layers one atop the other with the structured arrangement of wick elements of different sizes or types in certain locations on each subsequent layer.
Type: Application
Filed: Jul 27, 2007
Publication Date: Jan 29, 2009
Inventors: Paul Hoffman (San Diego, CA), Rajiv Tandon (San Diego, CA), Ralph Remsburg (San Diego, CA), Tadej Semenic (San Diego, CA), Chu-wan Hong (San Diego, CA), Che-Yin Lee (San Diego, CA)
Application Number: 11/878,809
International Classification: F28D 15/00 (20060101);