Title:
Vapor chamber structure with improved wick and method for manufacturing the same
Kind Code:
A1


Abstract:
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.



Inventors:
Hoffman, Paul (San Diego, CA, US)
Tandon, Rajiv (San Diego, CA, US)
Remsburg, Ralph (San Diego, CA, US)
Semenic, Tadej (San Diego, CA, US)
Hong, Chu-wan (San Diego, CA, US)
Lee, Che-yin (San Diego, CA, US)
Application Number:
11/878809
Publication Date:
01/29/2009
Filing Date:
07/27/2007
Primary Class:
Other Classes:
165/104.21
International Classes:
F28D15/00
View Patent Images:



Primary Examiner:
ROSATI, BRANDON MICHAEL
Attorney, Agent or Firm:
ROSENBERG, KLEIN & LEE (ELLICOTT CITY, MD, US)
Claims:
What is claimed is:

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.

Description:

BACKGROUND OF THE INVENTION

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.

Referring to FIG. 1, the prior art provides a vapor chamber 9 that has an airtight casing 90. Moreover, the casing 90 is made of metal material and has a hollow portion 900. The air in the hollow portion 900 is pumped away, and a working fluid (not shown) is filled into the hollow portion 900. The casing 90 has a wick structure 91 formed on an internal wall thereof. The chamber 9 is evacuated and charged with the working fluid, such as distilled water, which boils at normal operating temperatures. External to the vapor chamber 9 there is a heat-generating source 92. As the heat-generating source 92 dissipates heat it causes the working fluid to boil and evaporate. The resultant vapor (as the upward arrows) travels to the cooler section of the chamber 9 which in this case is a top where an optional finned structure 93 is located. At this point the vapor condenses giving off its latent heat energy. The condensed fluid (as the downward arrows) now returns down through the wick structure 91 to the bottom of the chamber 9 nearest the heat-generating source 92 where a new cycle occurs.

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 INVENTION

One 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.

BRIEF DESCRIPTION OF THE DRAWINGS

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:

FIG. 1 is a cross-sectional, schematic view of a vapor chamber structure of the prior art;

FIG. 2 is a perspective, exploded view of a vapor chamber structure according to the first embodiment of the present invention;

FIG. 3 is a perspective, assembled view of a vapor chamber structure according to the first embodiment of the present invention;

FIG. 4 is a cross-sectional view along line 4-4 of a vapor chamber structure shown in FIG. 3;

FIG. 5 is a cross-sectional view along line 5-5 of a vapor chamber structure shown in FIG. 3,

FIG. 6 is a cross-sectional, schematic view of a vapor chamber with a wick that is discontinuous along the casing surface in one or more areas,

FIG. 7 is a schematic view of a structure strengthening body composed of a solid post and an outer wick layer,

FIG. 8 is a schematic view of structure strengthening body composed of an outer metal solid layer and an inner wick layer,

FIG. 9A is a top view of a vapor chamber with a series of channels, some being micro-channels (width less than 200 microns) whose main purpose it to promote or nucleate boiling of the working fluid and some being channels (width greater than 200 microns) whose main purpose is to promote condensed fluid return flow from condensing areas of the vapor chamber to evaporating areas of the vapor chamber,

FIG. 9B is a cross-section view of a vapor chamber with a series of channels, some, being micro-channels (width less than 200 microns) whose main purpose it to promote or nucleate boiling of the working fluid and some being channels (width greater than 200 microns) whose main purpose is to promote condensed fluid return flow from condensing areas of the vapor chamber to evaporating areas of the vapor chamber,

FIG. 10 is a cross-sectional, schematic view of a vapor chamber having one or more channels in a casing, such channels overlaid by a wick material that also contacts the casing. The wick elements are of such a size or structure such that they do not fill the channels,

FIG. 10A shows a detail feature of a portion of FIG. 10,

FIG. 11 is a cross-sectional, schematic view of a vapor chamber having one or more channels in a casing, such channels filled by a first wick material and overlaid by a second wick material that also contacts the casing,

FIG. 11A shows a detail feature of a portion of FIG. 11,

FIG. 12 is a cross-section, schematic view of a vapor chamber having a wick structure that varies in thickness on the condenser side of the chamber—being thinner at the location with the longest working fluid travel path from heat source (typically the central portion) and thicker at the location with the shortest working fluid travel path from the heat source (typically the peripheral portion),

FIG. 13 is a cross-section, schematic view of a vapor chamber having a wick structure that varies in thickness on the condenser side of the chamber—being thinner at the location with the longest working fluid travel path from heat source (typically the central portion) and thicker at the location with the shortest working fluid travel path from the heat source (typically the peripheral portion), and including one or more channels within the wick structure to further promote fluid flow,

FIG. 14 is a cross-section, schematic view of a vapor chamber having a wick structure that varies in thickness on the evaporator side of the chamber—being thicker near the heat source (typically the central portion) and thinner away from the heat source (typically the peripheral portion), and optionally including one or more channels within the wick structure to further promote fluid flow

FIG. 15 is a top view of a vapor chamber having a wick structure that varies in a patch-wise manner,

FIG. 15A is a cross-section view of a vapor chamber having a wick structure that varies in a patch-wise manner,

FIG. 16 is a schematic view of a wick composed of different size metal powders stacked with each other from the large size powder to the small size powder;

FIG. 17 is a schematic view of a wick composed of different size metal powders stacked with each other from the small size powders to large size powers;

FIG. 18 is a cross-section, schematic view of a vapor chamber with wick formed from a continuous or step-wise continuous gradient of wick material,

FIG. 19 is a cross-section, schematic view of a vapor chamber having a multi-layered wick structure,

FIG. 20 is a top view of a vapor chamber having a multi-layered and patterned wick structure,

FIG. 20A is a cross-section view of a vapor chamber having a multi-layered and patterned wick structure,

FIG. 21 is a cross-section, schematic view of a vapor chamber having a complex wick structure formed by a plurality of wick cluster elements, each cluster being formed from two or more distinct types of wick materials (such as two different powder sizes),

FIG. 21A is a detail feature of a portion of FIG. 21,

FIG. 22 is a top view of a vapor chamber with two or more types of wicks, such wicks interdigitated with each other in the plan direction where they meet each other to promote better fluid flow between the two types of wicks,

FIG. 22A is a cross-section view of a vapor chamber with two or more types of wicks, such wicks interdigitated with each other in the plan direction where they meet each other to promote better fluid flow between the two types of wicks,

FIG. 23 is a top view of a vapor chamber two or more types of wicks, such wicks interdigitated with each other in the height direction where they meet each other to promote better fluid flow between the two types of wicks,

FIG. 23A is a cross-section view of a vapor chamber two or more types of wicks, such wicks interdigitated with each other in the height direction where they meet each other to promote better fluid flow between the two types of wicks,

FIG. 24 is a top view of a vapor chamber having one or more substantially radial wick geometries,

FIG. 24A is a cross-section view of a vapor chamber having one or more substantially radial wick geometries,

FIG. 25 is a top view of a vapor chamber having one or more substantially circular or ovoid wick geometries,

FIG. 25A is a cross-section view of a vapor chamber having one or more substantially circular or ovoid wick geometries,

FIG. 26 is an isometric, schematic view of a vapor chamber that includes one or more extended surfaces, configured as protrusions on one or more of the casings,

FIG. 27 is an isometric, schematic view of a vapor chamber that includes one or more extended surfaces, configured as depressions or pits in one or more of the casings,

FIG. 28 is a cross-section, schematic view a vapor chamber where the wick completely fills the chamber,

FIG. 29 is a cross-section, schematic view of a vapor chamber where the multi-layered wick completely fills the chamber,

FIG. 30 is a cross-section, schematic view of a wick for a vapor chamber containing at least some wick elements that are preferentially coated on their exterior surface to promote easier joining of the wick to the casing or to each other,

FIG. 30A shows a detail feature of portion B of FIG. 30,

FIG. 31 is a top view schematic of a pre-fabricated vapor chamber wick,

FIG. 31A is a cross-section view schematic of a pre-fabricated vapor chamber wick,

FIG. 32 is a top view of a pre-fabricated, multi-layer vapor chamber wick,

FIG. 32A is a cross-section view of a pre-fabricated, multi-layer vapor chamber wick,

FIG. 33 is a flowchart of a method for manufacturing a vapor chamber structure of one embodiment of the present invention,

FIG. 34A is a top view of the first step of a method for manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 34a is a cross-section view of the first step of a method for manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 34B is a top view of the second step of a method for manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 34b is a cross-section view of the second step of a method for manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 34C is a top view of the third step of a method for manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 34c is a cross-section view of the third step of a method for manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 34D is a cross-section view of the fourth step of a method for manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35A is a top view of the first step of another method for manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35a is a cross-section view of the first step of another method for manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35B is a top view of the second step of another method for manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35b is a cross-section view of the second step of another method for manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35C is a top view of the third step of another method for manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35c is a cross-section view of the third step of another method for manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35D is a top view of the fourth step of another method for manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35d is a cross-section view of the fourth step of another method for manufacturing a multi-layer wick on to a vapor chamber casing,

FIG. 35E is a cross-section view of a vapor chamber by affixing a pre-fabricated wick structure to one or more casings of a vapor chamber.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 2 to 5, the first embodiment of the present invention provides a vapor chamber structure 1a, comprising: a casing 10, a working fluid 20, a wick layer 12, and at least one structure strengthening bodies 13.

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 FIG. 2, a filling pipe 15 is shown). The filling pipe 15 has an opening side 151 formed on one side thereof and a closed side 152 formed on the other side thereof. The filling pipe 15 is arranged at the periphery of the casing 10 (e.g. a corner). Hence, before the closed side 152 of the filling pipe 15 is sealed, the working fluid 20 can be guided via the filling pipe 15 and be filled into a receiving chamber that is composed of the upper casing 101 and the lower casing 102. Moreover, the air in the receiving chamber is pumped away and the closed side 152 of the filling pipe 15 is sealed, so that the receiving chamber becomes the airtight vacuum chamber 100.

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 FIG. 5). Furthermore, in order to increase the surfaces in contact in the joint area the filling pipe 15 can have an ovoid or other non-circular cross-section. The location of the filling pipe 15 with respect to the periphery of the top casings can be also fixed by features on the filling pipe (e.g. a rib or groove) that mate to corresponding features on the casing.

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 FIG. 4). Each backflow accelerating body 14 can be a metal powder post that is formed via a sintering method. Furthermore, the backflow accelerating bodies 14 are dispersed to peripheral positions or other positions that are preferential to the backflow path of the condensed and relatively cold working fluid of the airtight vacuum chamber 100. Referring to FIGS. 7 and 8, according to the designer's need, each structure strengthening body 13′ can be composed of a solid post 130′ and a wick layer 131′ circumferentially covering an external surface of the solid post 130′. Each backflow accelerating body 14′ can be composed of a wick post 140′ and a metal solid layer 141′ covered circumferentially on an external surface of the wick post 140′. The wick can be fabricated with any suitable process and materials—to include but not be limited to metal powders, meshes, or small grooves on the surface of the structural strengthening element. However, the structure strengthening body 13 and the backflow accelerating body 14 are not shown in following drawings.

Referring to FIG. 6, a wick 12 is dispersed on one or more of the casings in a discontinuous fashion and at least one separated portion of the wick 16 are disposed to isolate the wick layer 12. The wick layer can be preferentially placed in those areas that will most benefit by its presence (e.g. for nucleating boiling at the evaporator or promoting working fluid return flow to the evaporator in other locations), and can preferentially remain absent in those areas that would have little to no benefit from the presence of the wick. In this way the usage of wick material can be minimized and the fabrication process simplified resulting in higher assembly yield. For example, in some cases a wick may only be required on the bottom casing 102 and not the top casing 101 (not shown).

Referring to FIGS. 9A and 9B, a vapor chamber with a series of channels formed in the casing, some being micro-channels 18 (width less than 200 microns) whose main purpose is to promote or nucleate boiling of the working fluid and some being channels 17 (width greater than 200 microns) whose main purpose is to promote condensed fluid return flow from condensing areas of the vapor chamber to evaporating areas of the vapor chamber. These channels may be arranged and arrayed in any fashion required to serve the purpose of nucleating boiling at one or more locations in the vapor chamber and to serve the purpose of returning working fluid 20 to the evaporator from one or more condensing locations in the vapor chamber. Furthermore, the micro-channels 18 and channels 17 can have features that promote or control the fluid flow within them, such as the channels being of varying width along their length, the channels being of varying depth along their length or the channels having varying surface textures along their length. These features can be combined in any combination to achieve the desired fluid flow results.

Referring to FIGS. 10 and 10A, a vapor chamber having at least one channel 17 in a casing 10 is provided, such channels 17 overlaid by a wick layer 12′ formed by a plurality of second wick elements that also contacts the casing 10. The wick layer 12 is formed by a plurality of first wick elements. The second wick elements are of such a size or structure different from the first wick element such that they do not fill the channels 17, thereby keeping the channels open for fluid flow.

Referring to FIGS. 11 and 11A, a vapor chamber having at least one channel 17 in a casing 10 is provided, such channels filled by a first wick element of the wick layer 12 and overlaid by a second wick layer 12′ that also contacts the casing 10. The second wick elements 122 of wick 12′ are of such a size or structure that they do not fill the channels 17, whereas the elements 120 of wick layer 12 are of such a size that they do fill the channels 17. The wick layer 12 and its elements 120 are chosen not only to be able to fill the channels 17 but to promote either fluid flow in the channels 17 or nucleate boiling in the channels 17 in the evaporator region.

Referring to FIG. 12, the vapor chamber 10 has a wick structure that varies in thickness on the condenser side of the chamber (in this case on the top casing 101)—being thinner at the location with the longest working fluid travel path from the heat source (typically the central portion) and thicker at the location with the shortest working fluid travel path from the heat source (typically the peripheral portion). The varying wick thickness will promote varying levels of capillary force and therefore fluid flow, such that the wick can be thicker and therefore provide higher fluid flow in those areas that would benefit from higher flow and vice versa can be thinner and provide less flow in those areas that require less flow.

Referring to FIG. 13, the vapor chamber 10 has a wick structure that varies in thickness on the condenser side of the chamber (in this case on the top casing 101)—being thinner at the location with the longest working fluid travel path from the heat source (typically the central portion) and thicker at the location with the shortest working fluid travel path from the heat source (typically the peripheral portion). The varying wick thickness will promote varying levels of capillary force and therefore fluid flow, such that the wick can be thicker and therefore provide higher fluid flow in those areas that would benefit from higher flow and vice versa can be thinner and provide less flow in those areas that require less flow. Furthermore the wick structure 12 has micro-channels 18 formed into it to further promote fluid flow.

Referring to FIG. 14, the vapor chamber 10 has a wick structure that varies in thickness on the evaporator side of the chamber (in this case on the bottom casing 102)—being thicker at the location with the shortest working fluid travel path from the heat source (typically the central portion) and thinner at the location with the longest working fluid travel path from the heat source (typically the peripheral portion). The varying wick thickness will promote varying levels of capillary force and therefore fluid flow, such that the wick can be thicker and therefore provide higher fluid flow in those areas that would benefit from higher flow and vice versa can be thinner and provide less flow in those areas that require less flow. Furthermore the wick structure 12 can include optional flow micro-channels 18 that further promote fluid flow.

Referring to FIGS. 15 and 15A, there is provided a vapor chamber having a wick structure that varies in a patch-wise manner. The wick is composed of two or more wick structures, such as 12 and 12′, with each preferentially placed in predetermined areas or patches that take advantage of the particular features and benefits of those wick structures. For example, a patch or patches composed of a wick structure 12′ optimized for nucleate boiling might be located on the evaporator areas of the vapor chamber while a patch or patches composed of a wick structure 12 optimized for fluid flow might be located on the condenser areas and between the condenser and evaporating areas of the vapor chamber.

Referring to FIG. 16, a vapor chamber is provided that utilizes a wick 12 composed of different size elements stacked with each other from the large size elements 122 to the small size elements 120. Although powders are depicted, it will be understood that other appropriate wick structures (e.g. wire mesh) could likewise be arranged in this fashion.

Referring to FIG. 17, a vapor chamber is provided that utilizes a wick 12 composed of different size elements stacked with each other from the small size elements 120 to large size elements 122. Although powders are depicted, it will be understood that other appropriate wick structures (e.g. wire mesh) could likewise be arranged in this fashion.

Referring to FIG. 18, a vapor chamber with wick 12 formed from a continuous or step-wise continuous gradient of wick material is provided. For example, the wick can be composed of elements of varying size from small sized elements 120, to intermediate sized elements 121, to larger sized elements 122. The gradients can be arranged in any fashion (increasing or decreasing element size with distance) or in multiple areas to achieve the boiling and fluid flow properties desired.

Referring to FIG. 19, a vapor chamber is provided having a multi-layered wick structure, composed of at least one layers of a first wick type 12 and at least one layers of a second wick type 12′. In this embodiment, one layers of a second wick type 12′ is disposed between the two layers of a first wick type 12 to from a sandwich-like structure contacted with the bottom casing 102. The layers are formed by wicks of varying properties, depicted here as alternating layers of wick 12 and wick 12′, although the number of types, number of layers, thickness and other features of such wicks will be designed to yield the desired function and performance of the wicks in the vapor chamber.

Referring to FIGS. 20 and 20A, a vapor chamber is provided having a multi-layered and patterned wick structure, composed of two or more wick structures 12 and 12′, layered one over the other, and with areas that may be patterned in certain shapes or structures. Furthermore there may be means of communicating from a layer of one wick type 12 to another layer of similar wick type 12 by way of a fluid accelerating body 14. The layers are formed by wicks of varying properties, depicted here as alternating layers of wick 12 and wick 12′, although the number, thickness and other features of such wicks will be designed to yield the desired function and performance of the wicks in the vapor chamber.

Referring to FIGS. 21 and 21A, a vapor chamber is provided having a complex wick structure 40 formed by a plurality of wick cluster elements 410, each cluster 410 being formed from two or more distinct types of wick materials (such as two different powder sizes 411 and 412). Between and among the powder particles or other wick elements (e.g. wire mesh or other) there are pores or open spaces of generally a small size, while between and among the clusters 410 there are relatively large pores or open spaces 413. Thus this wick structure 40 can provide a complexly varying type and amount and size of pores or open spaces, which can be optimized to promote boiling in some regions and capillary fluid return flow in other areas. Furthermore the complex wick structure 40 can be combined in use with a less complex wick structure 12 within the same vapor chamber. The complex wick structure 40 can also be provided with attributes as previously described elsewhere in this invention—such as configuration patches or variation in thickness or inter-digitation with other wick structures, or any and all of the previously described structures or applications.

Referring to FIGS. 22 and 22A, a vapor chamber is provided having two or more types of wicks 12 and 12′, such wicks interdigitated with each other in the plan direction where they meet each other to promote better fluid flow between the two or more types of wicks. Such wicks may also be a combination of both powder materials and wire mesh materials.

Referring to FIGS. 23 and 23A, a vapor chamber is provided having two or more types of wicks 12 and 12′, such wicks interdigitated with each other in the height direction where they meet each other to promote better fluid flow between the two or more types of wicks. Such wicks may also be a combination of both powder materials and wire mesh materials.

Referring to FIGS. 24 and 24A, a vapor chamber is provided having one or more substantially radial wick geometries 12′. The radial wick 12′ is embedded in the wick 12 to form the wick structure.

Referring to FIGS. 25 and 25A, a vapor chamber is provided having one or more substantially circular or ovoid wick geometries 12 and 12′.

Referring to FIG. 26, a vapor chamber is provided that includes at least one extended surface, configured as protrusions 104 having predetermined height from one or more of the casings 10. The extended surface, coated with the wick 12, provides additional surface area to promote boiling and evaporation on those parts of the vapor chamber adjacent to the heat source and likewise an extended surface will improve the heat transfer on the condensing portions of the vapor chamber (not shown), thus improving the thermal efficiency of the vapor chamber.

Referring to FIG. 27, a vapor chamber is provided that includes one or more extended surfaces, configured as depressions or pits or channels 17 in one or more of the casings 10. The extended surface, coated with the wick 12, provides additional surface area to promote boiling and evaporation on those parts of the vapor chamber adjacent to the heat source and likewise an extended surface will improve the heat transfer on the condensing portions of the vapor chamber (not shown), thus improving the thermal efficiency of the vapor chamber.

Referring to FIG. 28, a vapor chamber is provided where the wick element 12 completely fills the vacuum chamber 100 between the casings 101 and 102 to form the wick layer 12. In this case the wick material itself is able to strengthen the vapor chamber and allow it to support a much higher applied load or force than a vapor chamber with some amount of empty, unfilled space in the vacuum chamber 100.

Referring to FIG. 29, a vapor chamber is provided where a multi-layered wick completely fills the vacuum chamber 100 to form a sandwich-like structure between the casings 101 and 102. In this case the wick elements themselves are able to strengthen the vapor chamber and allow it to support a much higher applied load or force than a vapor chamber with some amount of empty, unfilled space in the vacuum chamber 100. The layers are formed by wicks of varying properties, depicted here as alternating layers of wick 12 and wick 12′, although the number, thickness and other features of such wicks will be designed to yield the desired function and performance of the wicks in the vapor chamber.

Referring to FIGS. 30 and 30A, a vapor chamber is provided containing a wick 12 where at least some wick elements 121 are preferentially coated on their exterior surface by a coating layer 124 to promote easier joining of the wick to the casing 102 or of the wick elements 121 to themselves. For example a Nickel-Phosphorous coating on copper wick elements could help promote and accelerate the sintering or diffusion bonding of those elements to each other or to a casing 102, such casing typically made of brass, copper or steel.

Referring to FIGS. 31 and 31A, a pre-fabricated vapor chamber wick is provided. A wick layer 12 can be pre-fabricated outside and apart from the vapor chamber. The wick layer can integrally include features such as channels 17, protrusions 126, and holes 125. A prefabricated wick can also include any and all of the features or elements noted elsewhere in this disclosure for wicks fabricated within the vapor chamber. For example the figure shows solid structural strengthening elements 13 (both adhered to an outer surface of the wick or embedded in a hole in the wick) or porous fluid accelerating bodies 14, or other features or elements not shown in the figure such as gradient wick elements, patch-wise wick structures and the like. Furthermore, the wick layer itself may be patterned in such fashion as to promote fluid boiling, condensation or fluid flow depending on the wick function required at various locations within the vapor chamber.

Referring to FIGS. 32 and 32A, a pre-fabricated, multi-layer vapor chamber wick is provided. Two or more wick layers, composed of two or more types of wick elements (e.g. 12 and 12′) are stacked one atop the other. Such layers also may include other features such as holes or channels (not shown) or porous fluid accelerating bodies 14—with the option of including or not including any of the features previously mentioned in this invention on any layer. Furthermore, each wick layer itself may be patterned in such fashion as to promote fluid boiling, condensation or fluid flow depending on the wick function required at various locations within the vapor chamber—as shown in the plan views. Finally the number of wick layers and their thickness and the type of wick element used within each layer will also be chosen to promote fluid flow or nucleate boiling as required within the vapor chamber.

Referring to FIG. 33, the present invention provides a method for manufacturing a vapor chamber structure of one embodiment of the present invention. The method comprises providing a casing 10 that is composed of an upper casing 101 and a lower casing 102 (S101); forming a wick layer 12 on an internal surface of the casing 10 (S102) and then respectively arranging a plurality of structure strengthening bodies 13 and a plurality of backflow accelerating bodies 14 between the upper casing 101 and the lower casing 102 (S103). The manufacturing steps S102 and S103 can be alternatively replaced. As shown in FIG. 33, after S101, a plurality of structures are first arranged (S103′) and then forming a wick layer on the internal surface (S102′).

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).

Referring to FIGS. 34a-34c and 34A-34D, a series of drawings depicting a method for manufacturing a multi-layer wick on to a vapor chamber casing 10 is provided. In this method a first wick layer 12 is deposited on the casing 102 (S111), such layer also may include other features such as holes or channels (not shown) or porous fluid accelerating bodies 14. Then a second wick layer 12′ is deposited over the first wick layer (S113), such second wick layer also may include other features such as holes or fluid accelerating bodies (not shown) or channels 17. Subsequently a third wick layer 12 and a fourth wick layer 12′ are deposited (S115)—with the option of including or not including any of the features previously mentioned (fluid accelerating bodies, channels, holes and the like). Furthermore, each wick layer itself may be patterned in such fashion as to promote fluid boiling, condensation or fluid flow depending on the wick function required at various locations within the vapor chamber—as shown in the plan views. Finally the number of wick layers and their thickness will also be chosen to promote fluid flow or nucleate boiling as required within the vapor chamber. Then, the upper casing 101 and the lower casing 102 are assembled together (S117).

Referring to FIGS. 35a-35d and 35A-35E, a series of drawings showing the sequence of steps in the manufacture of a pre-fabricated, multi-layer wick for a vapor chamber is provided. In this method a first wick layer 12 is fabricated (S211), such layer also may include other features such as holes or channels (not shown) or porous fluid accelerating bodies 14. Then a second wick layer 12′ is deposited over the first wick layer (S212), such second wick layer also may include other features such as holes or fluid accelerating bodies (not shown) or channels 17. Subsequently a third wick layer 12 and a fourth wick layer 12′ are deposited (S213)—with the option of including or not including any of the features previously mentioned (fluid accelerating bodies, channels, holes and the like). Furthermore, each wick layer itself may be patterned in such fashion as to promote fluid boiling, condensation or fluid flow depending on the wick function required at various locations within the vapor chamber—as shown in the plan views. Finally the number of wick layers and their thickness and the type of wick elements within each wick layer will also be chosen to promote fluid flow or nucleate boiling as required within the vapor chamber.

FIG. 35E is a cross-section view of a vapor chamber by affixing a pre-fabricated wick structure to one or more casings of a vapor chamber. First, to dispose the multi-layer wick inside the lower casing 102 (S215) and then the upper casing 101 and the lower casing 102 are assembled together (S217). In conclusion, the vapor chamber structure of the present invention has capabilities as a backflow accelerating function and improved boiling function due to the usage of backflow accelerating bodies 14 or improved wick structures 12. Therefore, the present invention can increase the backflow velocity of the working fluid 20 and the boiling of the working fluid due to the match backflow accelerating bodies 14 and improved wick structures 12. Because the backflow velocity of the working fluid 20 is increased and the boiling function is improved, the heat-transmitting efficiency is increased.

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.