U.S. patent application number 12/821488 was filed with the patent office on 2010-12-09 for vapor chamber structure with improved wick and method for manufacturing the same.
This patent application is currently assigned to AMULAIRE THERMAL TECHNOLOGY, INC.. Invention is credited to PAUL HOFFMAN, CHU-WAN HONG, CHE-YIN LEE, RALPH REMSBURG, TADEJ SEMENIC, RAJIV TANDON.
Application Number | 20100307003 12/821488 |
Document ID | / |
Family ID | 40294236 |
Filed Date | 2010-12-09 |
United States Patent
Application |
20100307003 |
Kind Code |
A1 |
HOFFMAN; PAUL ; et
al. |
December 9, 2010 |
VAPOR CHAMBER STRUCTURE WITH IMPROVED WICK AND METHOD FOR
MANUFACTURING THE SAME
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) ; TANDON; RAJIV; (SAN DIEGO, CA) ;
REMSBURG; RALPH; (SAN DIEGO, CA) ; SEMENIC;
TADEJ; (SAN DIEGO, CA) ; HONG; CHU-WAN; (SAN
DIEGO, CA) ; LEE; CHE-YIN; (SAN DIEGO, CA) |
Correspondence
Address: |
ROSENBERG, KLEIN & LEE
3458 ELLICOTT CENTER DRIVE-SUITE 101
ELLICOTT CITY
MD
21043
US
|
Assignee: |
AMULAIRE THERMAL TECHNOLOGY,
INC.
SAN DIEGO
CA
|
Family ID: |
40294236 |
Appl. No.: |
12/821488 |
Filed: |
June 23, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11878809 |
Jul 27, 2007 |
|
|
|
12821488 |
|
|
|
|
Current U.S.
Class: |
29/890.032 |
Current CPC
Class: |
Y10T 29/49353 20150115;
H01L 2924/0002 20130101; H01L 2924/00 20130101; H01L 2924/0002
20130101; F28D 15/046 20130101; H01L 23/427 20130101 |
Class at
Publication: |
29/890.032 |
International
Class: |
B21D 53/02 20060101
B21D053/02 |
Claims
1. 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.
2. The method as claimed in claim 1 wherein the joining method for
the wick elements is by a high temperature process over 350 degrees
Celsius.
3. The method as claimed in claim 2 wherein the joining method is
chosen from sintering, diffusion bonding, copper-copper oxide
eutectic bonding, or brazing.
4. The method as claimed in claim 1 wherein the method reduces the
wick layer thickness in certain locations.
5. The method as claimed in claim 4 wherein wick elements are
reduced in number or eliminated in those areas of reduced wick
layer thickness.
6. The method as claimed in claim 5 wherein adjoined wick elements
are compressed in those areas of reduced wick layer thickness.
7. The method as claimed in claim 1 wherein the method increases
the wick layer thickness in certain locations.
8. The method as claimed in claim 7 wherein wick elements are
increased in number in those areas of increased wick layer
thickness.
9. The method as claimed in claim 1 wherein the method includes the
addition of structure strengthening bodies to the wick layer in
certain locations.
10. The method as claimed in claim 1 wherein the method includes
the addition of backflow accelerating bodies to the wick layer in
certain locations.
11. The method as claimed in claim 1 wherein the method includes
bending or forming the wick layer in certain locations.
12. The method as claimed in claim 1 wherein the method includes
the use of wick elements of different sizes or types.
13. The method as claimed in claim 12 wherein the method includes
arranging certain of the wick elements by size or type within
certain areas of the wick.
14. The method as claimed in claim 13 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.
15. The method as claimed in claim 13 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.
16. The method as claimed in claim 13 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.
17. The method as claimed in claim 16 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.
18. The method as claimed in claim 13 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.
19. The method as claimed in claim 18 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.
20. The method as claimed in claim 19 wherein the method provides
communication between patches by creating pathways between patches
of the same wick element that forms the patches.
21. The method as claimed in claim 19 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.
22. The method as claimed in claim 13 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
RELATED APPLICATIONS
[0001] This application is a Divisional patent application of
co-pending application Ser. No. 11/878,809, filed on 27 Jul. 2007.
The entire disclosure of the prior application Ser. No. 11/878,809,
from which an oath or declaration is supplied, is considered a part
of the disclosure of the accompanying Divisional application and is
hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] 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.
[0004] 2. Description of the Related Art
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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
[0011] 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.
[0012] 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.
[0013] 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.
[0014] Therefore, the present invention can improve the thermal
performance of the vapor chamber due to the use of the improved
wick structures.
[0015] 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
[0016] 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:
[0017] FIG. 1 is a cross-sectional, schematic view of a vapor
chamber structure of the prior art;
[0018] FIG. 2 is a perspective, exploded view of a vapor chamber
structure according to the first embodiment of the present
invention;
[0019] FIG. 3 is a perspective, assembled view of a vapor chamber
structure according to the first embodiment of the present
invention;
[0020] FIG. 4 is a cross-sectional view along line 4-4 of a vapor
chamber structure shown in FIG. 3;
[0021] FIG. 5 is a cross-sectional view along line 5-5 of a vapor
chamber structure shown in FIG. 3,
[0022] 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,
[0023] FIG. 7 is a schematic view of a structure strengthening body
composed of a solid post and an outer wick layer,
[0024] FIG. 8 is a schematic view of structure strengthening body
composed of an outer metal solid layer and an inner wick layer,
[0025] 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,
[0026] 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,
[0027] 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,
[0028] FIG. 10A shows a detail feature of a portion of FIG. 10,
[0029] 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,
[0030] FIG. 11A shows a detail feature of a portion of FIG. 11,
[0031] 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),
[0032] 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,
[0033] 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
[0034] FIG. 15 is a top view of a vapor chamber having a wick
structure that varies in a patch-wise manner,
[0035] FIG. 15A is a cross-section view of a vapor chamber having a
wick structure that varies in a patch-wise manner,
[0036] 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;
[0037] 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;
[0038] 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,
[0039] FIG. 19 is a cross-section, schematic view of a vapor
chamber having a multi-layered wick structure,
[0040] FIG. 20 is a top view of a vapor chamber having a
multi-layered and patterned wick structure,
[0041] FIG. 20A is a cross-section view of a vapor chamber having a
multi-layered and patterned wick structure,
[0042] 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),
[0043] FIG. 21A is a detail feature of a portion of FIG. 21,
[0044] 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,
[0045] 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,
[0046] 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,
[0047] 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,
[0048] FIG. 24 is a top view of a vapor chamber having one or more
substantially radial wick geometries,
[0049] FIG. 24A is a cross-section view of a vapor chamber having
one or more substantially radial wick geometries,
[0050] FIG. 25 is a top view of a vapor chamber having one or more
substantially circular or ovoid wick geometries,
[0051] FIG. 25A is a cross-section view of a vapor chamber having
one or more substantially circular or ovoid wick geometries,
[0052] 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,
[0053] 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,
[0054] FIG. 28 is a cross-section, schematic view a vapor chamber
where the wick completely fills the chamber,
[0055] FIG. 29 is a cross-section, schematic view of a vapor
chamber where the multi-layered wick completely fills the
chamber,
[0056] 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,
[0057] FIG. 30A shows a detail feature of portion B of FIG. 30,
[0058] FIG. 31 is a top view schematic of a pre-fabricated vapor
chamber wick,
[0059] FIG. 31A is a cross-section view schematic of a
pre-fabricated vapor chamber wick,
[0060] FIG. 32 is a top view of a pre-fabricated, multi-layer vapor
chamber wick,
[0061] FIG. 32A is a cross-section view of a pre-fabricated,
multi-layer vapor chamber wick,
[0062] FIG. 33 is a flowchart of a method for manufacturing a vapor
chamber structure of one embodiment of the present invention,
[0063] 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,
[0064] 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,
[0065] 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,
[0066] 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,
[0067] 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,
[0068] 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,
[0069] 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,
[0070] 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,
[0071] 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,
[0072] 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,
[0073] 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,
[0074] 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,
[0075] 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,
[0076] 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,
[0077] 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,
[0078] 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
[0079] 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.
[0080] 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.
[0081] 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.
[0082] 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.
[0083] 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.
[0084] 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 1a.
[0085] 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.
[0086] 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.
[0087] 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).
[0088] 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.
[0089] 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.
[0090] 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.
[0091] 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.
[0092] 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.
[0093] 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.
[0094] 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.
[0095] 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.
[0096] 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.
[0097] 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.
[0098] 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.
[0099] 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.
[0100] 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.
[0101] 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.
[0102] 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.
[0103] 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.
[0104] Referring to FIGS. 25 and 25A, a vapor chamber is provided
having one or more substantially circular or ovoid wick geometries
12 and 12'.
[0105] 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.
[0106] 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.
[0107] 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.
[0108] 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.
[0109] 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.
[0110] 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.
[0111] 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.
[0112] 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').
[0113] 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).
[0114] 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).
[0115] 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.
[0116] 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.
[0117] 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.
* * * * *