U.S. patent application number 10/219255 was filed with the patent office on 2002-12-26 for laminated heat transfer device and method of producing thereof.
Invention is credited to Siu, Wing Ming.
Application Number | 20020195231 10/219255 |
Document ID | / |
Family ID | 26770641 |
Filed Date | 2002-12-26 |
United States Patent
Application |
20020195231 |
Kind Code |
A1 |
Siu, Wing Ming |
December 26, 2002 |
Laminated heat transfer device and method of producing thereof
Abstract
A laminated heat transfer device for cooling or thermal energy
transport applications and a method of manufacture thereof. In
various implementations, the laminated heat transfer device
provides complex duct channels for efficient cooling. The various
implementations are compatible and integrateable with each
other.
Inventors: |
Siu, Wing Ming; (Kowloon
City, HK) |
Correspondence
Address: |
HEATHER MORIN
Fish & Richardson P.C.
11th Floor
1425 K Street, N.W.
Washington
DC
20005-3500
US
|
Family ID: |
26770641 |
Appl. No.: |
10/219255 |
Filed: |
August 16, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10219255 |
Aug 16, 2002 |
|
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10084138 |
Feb 28, 2002 |
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60282170 |
Apr 9, 2001 |
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Current U.S.
Class: |
165/104.33 ;
257/E23.103 |
Current CPC
Class: |
B23P 15/26 20130101;
H01L 23/3672 20130101; F28F 3/02 20130101; H01L 2924/0002 20130101;
H01L 2924/0002 20130101; H01L 2924/00 20130101; B23P 2700/10
20130101; B23P 2700/12 20130101; B21D 53/04 20130101 |
Class at
Publication: |
165/104.33 |
International
Class: |
F28D 015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 9, 2002 |
TW |
PCT/GB02/01657 |
Mar 28, 2002 |
91106203 |
Claims
What is claimed is:
1. A laminated heat transfer device, comprising a base; and a vane
formed from a plurality of laminae, each lamina having a plurality
of fins and a conduction core, wherein the laminae are stacked
according to a predetermined sequence.
2. The laminated heat transfer device of claim 1, further
comprising: at least one guide rod to guide the stacking of
laminae.
3. The laminated heat transfer device of claim 1, further
comprising: an alignment fixture to guide the stacking of
laminae.
4. The laminated heat transfer device of claim 3, wherein the
stacking of laminae comprises folding a lamina upon itself.
5. The laminated heat transfer device of claim 3, wherein the
stacking of laminae comprises piling a lamina upon itself.
6. The laminated heat transfer device of claim 3, wherein the
stacking of laminae comprises a combination of folding and piling a
lamina.
7. The laminated heat transfer device of claim 1, wherein the
laminae are of equal size or varying size.
8. The laminated heat transfer device of claim 1, wherein the
laminae are shaped like spokes of a wheel.
9. The laminated heat transfer device of claim 1, wherein at least
one of the laminae is shaped like a web.
10. The laminated heat transfer device of claim 1, wherein the fins
of the heat sink form a spiral.
11. The laminated heat transfer device of claim 1, wherein the heat
sink is a ducting-type heat sink.
12. A laminated heat transfer device, comprising a base; and a
porous structure formed from a plurality of first and second
laminae, each lamina having a plurality of shaped openings, wherein
the laminae are stacked according to a predetermined sequence.
13. The laminated heat transfer device of claim 12, wherein the
stacking of laminae comprises folding a lamina upon itself.
14. The laminated heat transfer device of claim 12, wherein the
stacking of laminae comprises piling a lamina upon itself.
15. The laminated heat transfer device of claim 12, wherein the
stacking of laminae comprises a combination of folding and piling a
lamina.
16. The laminated heat transfer device of claim 12, wherein the
first and second laminae are alternately stacked and wherein the
laminae are stacked horizontally or vertically.
17. The laminated heat transfer device of claim 12, wherein the
shaped openings of each lamina are uniformly spaced.
18. The laminated heat transfer device of claim 12, wherein the
shaped openings of each lamina are non-uniformly spaced.
19. The laminated heat transfer device of claim 12, wherein the
shaped openings of each lamina are non-uniformly sized.
20. The laminated heat transfer device of claim 12, wherein the
shaped openings of each lamina comprise the shapes of a rectangle,
an oval, or a circle.
21. The laminated heat transfer device of claim 12, wherein the
laminae are of equal size or varying size.
22. The laminated heat transfer device of claim 12, wherein the
laminated heat transfer device is a heat sink.
23. The laminated heat transfer device of claim 22, wherein the
heat sink is a porous-type heat sink.
24. The laminated heat transfer device of claim 12, further
comprising: two end plates, and wherein the openings of the primary
and secondary laminae are different sizes in order to form grooves
when the laminae are stacked together.
25. The laminated heat transfer device of claim 24, wherein the
primary and secondary laminae are cut to form channels across the
laminae toward the end plates when the laminae are stacked
together.
26. The laminated heat transfer device of claim 24, further
comprising: two plates, each plate being formed with a plurality of
slits and positioned before the respective end plate.
27. The laminated heat transfer device of claim 24, wherein the
laminated heat transfer device is a heat pipe.
28. The laminated heat transfer device of claim 12, further
comprising: two end plates, and wherein the openings of the primary
and secondary laminae are the same size in order to form grooves
when the laminae are stacked together.
29. The laminated heat transfer device of claim 28, wherein the
primary and secondary laminae are cut to form channels across the
laminae toward the end plates when the laminae are stacked
together.
30. The laminated heat transfer device of claim 26, further
comprising: two plates, each plate being formed with a plurality of
slits and positioned before the respective end plate.
31. The laminated heat transfer device of claim 27, wherein the
laminated heat transfer device is a heat pipe.
32. A laminated heat transfer device, comprising a base; and a
plurality of laminae formed with thermo-electric junctions, the
laminae being stacked according to a predetermined sequence wherein
a first group of laminae are attached to the base and a second
group of laminae are thermally isolated.
33. The laminated heat transfer device of claim 32, wherein the
stacking of laminae comprises folding a lamina upon itself.
34. The laminated heat transfer device of claim 32, wherein the
stacking of laminae comprises piling a lamina upon itself.
35. The laminated heat transfer device of claim 32, wherein the
stacking of laminae comprises a combination of folding and piling a
lamina.
36. The laminated heat transfer device of claim 32, wherein the
laminated heat transfer device is a split-body Peltier device.
37. A laminated heat transfer device, comprising the laminated heat
transfer device as claimed in claim 1 formed integrally with the
laminated heat transfer device as claimed in claim 24.
38. A laminated heat transfer device, comprising the laminated heat
transfer device as claimed in claim 12 formed integrally with the
laminated heat transfer device as claimed in claim 24.
39. A laminated heat transfer device, comprising the laminated heat
transfer device as claimed in claim 24 formed integrally with the
laminated heat transfer device as claimed in claim 32.
40. A laminated heat transfer device, comprising the laminated heat
transfer device as claimed in claim 1 formed integrally with the
laminated heat transfer device as claimed in claim 25.
41. A laminated heat transfer device, comprising the laminated heat
transfer device as claimed in claim 12 formed integrally with the
laminated heat transfer device as claimed in claim 25.
42. A laminated heat transfer device, comprising the laminated heat
transfer device as claimed in claim 25 formed integrally with the
laminated heat transfer device as claimed in claim 32.
43. A method of producing a laminated heat device, comprising
specifying a three-dimensional structure as a plurality of laminae;
producing the laminae from sheets of working material; stacking the
laminae according to a predetermined sequence with a guiding
structure; and connecting the laminae.
44. The method of producing a laminated heat transfer device of
claim 43, wherein the stacking of laminae comprises folding a
lamina upon itself.
45. The method of producing a laminated heat transfer device of
claim 43, wherein the stacking of laminae comprises piling a lamina
upon itself.
46. The method of producing a laminated heat transfer device of
claim 43, wherein the stacking of laminae comprises a combination
of folding and piling a lamina.
47. The method of producing a laminated heat transfer device of
claim 43, wherein the laminated heat transfer device is a heat
sink.
48. The method of producing a laminated heat transfer device of
claim 43, wherein the laminated heat transfer device is a heat
pipe.
49. A laminated heat transfer device, comprising a plurality of
capillary structures formed from a plurality of lamina, the laminae
having geometric features, the laminae being stacked according to a
predetermined sequence.
50. The laminated heat transfer device of claim 49, further
comprising two end plates.
51. The laminated heat transfer of device of claim 49, wherein the
laminae being stacked comprises folding lamina upon itself.
52. The laminated heat transfer device of claim 49, wherein the
laminae being stacked comprises piling lamina upon itself.
53. The laminated heat transfer device of claim 49, wherein the
lamina being stacked comprises a combination of folding and piling
lamina.
54. A laminated heat transfer device, comprising a plurality of
capillary structures formed from a plurality of lamina, the laminae
being of different sizes, the laminae being stacked according to a
predetermined sequence.
55. The laminated heat transfer device of claim 54, further
comprising two end plates.
56. The laminated heat transfer of device of claim 54, wherein the
laminae being stacked comprises folding lamina upon itself.
57. The laminated heat transfer device of claim 54, wherein the
laminae being stacked comprises piling lamina upon itself.
58. The laminated heat transfer device of claim 54, wherein the
lamina being stacked comprises a combination of folding and piling
lamina.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 10/084,138, filed on Feb. 28, 2002, which
claims priority under 35 USC .sctn.119(e) to U.S. application Ser.
No. 60/282,170, filed on Apr. 9, 2001, the entire contents of which
are incorporated by reference.
TECHNICAL FIELD
[0002] This invention relates to a laminated heat transfer device
for cooling or thermal energy transport applications.
BACKGROUND
[0003] Heat is a by-product of electronic systems and the efficient
removal of heat is key to preventing failure of electronics. For
electronics, the most common methods of heat removal are heat
sinks, heat-pipes, and Peltier devices.
[0004] Heat sinks (also known as heat-fins) are
conduction-convection devices that remove heat by conducting heat
away from a source and then eject the heat into a working fluid
through convection. A heat sink balances the conduction and the
convection processes so that conduction resistance is not too
large, while convection resistance is small. In general, conduction
resistance will increase as the fin's design is changed to yield a
smaller convection resistance. Heat sinks can be either a ducting
type or a porous type. A ducting-type heat sink channels the flow
from a source so that the fluid flows over a maximum area of the
heat sink. This is particularly important, for example, where the
size of the heat sink is larger than the fan, and without the
channeling function, less surface undergoes forced-convective
cooling. In contrast, a porous-type heat sink does not channel the
flow, but instead allows the fluid to flow to or from three
directions. One example is a porous metallic foam, where the fluid
flow can come from any of the three orthogonal directions, and as
such, these heat sinks are useful in situations where the flow area
is larger than the heat sink.
[0005] A heat-pipe is a heat-transfer device that relies on the
evaporation and condensation of a working liquid. Normally, the
liquid evaporates from the hot side (called evaporator side) and
travels as a vapor to the cold side where it condenses back into
liquid (called condenser side). The liquid must then be carried
back to the evaporator side so that the cycle can start anew, which
is typically done by using a porous wick and the capillary action
of the liquid. As the heat of vaporization is typically very large,
the heat-pipe is generally capable of a relatively large heat
transfer rate. Indeed, heat-flux as high as 20 W/sq-cm has been
reported for complex wicking structures.
[0006] A Peltier device is a thermoelectric device where heat is
absorbed and rejected as an electric current flows through
dissimilar conductors. Current Peltier devices have thermal
back-diffusion.
SUMMARY
[0007] A laminated heat transfer device can be a laminated
ducting-type heat sink, a laminated porous-type heat sink with an
integrated base, a laminated heat-pipe, a laminated split-body
Peltier device, or any combination of these.
[0008] A laminated ducting-type heat sink includes ducting channels
for efficient air flow. Naturally convecting heat sinks include
chimneys with varying or constant cross-sectional areas for
flow-acceleration to provide fanless solutions. A ducting-type heat
sink includes cross-linkages to use the spaces between the guiding
vanes. This device is compatible and integrateable with the
laminated heat-pipe and/or laminated split-body Peltier devices,
described below.
[0009] A laminated porous-type heat sink includes an integrated
base structure to minimize contact resistance. The depth of the
base and its footprint varies with specific thermal requirement.
This device accommodates a spatially varying porous structure to
balance the convective and conductive thermal resistances. This
device is also compatible and integrateable with the laminated
heat-pipe and/or laminated split-body Peltier devices, described
below.
[0010] A laminated heat-pipe varies in size and can have different
wicking structures without using a sintering process. The wicking
structure is an integral part of the overall heat-pipe to minimize
thermal resistance. By stacking multiple laminae to form a hollow
enclosure, the wicking structure comes from either stacking the
laminae and/or aligning the laminae. This device is compatible and
integrateable with the laminated heat sinks and/or the laminated
split-body Peltier devices.
[0011] A laminated split-body Peltier device includes stacked
multiple laminae such that each layer is an electrically conducting
element of P-type and N-type materials. This device is compatible
and integrateable with the laminated heat sinks and/or the
laminated heat-pipe.
[0012] A method to produce the different implementations of a
laminated heat transfer device is also provided. The method
includes designing a three-dimensional structure into series of
planar elements (laminae), which may or may not be self-repeating
depending on the three-dimensional requirements; producing the
laminae from sheets of working material by stamping, punching,
etching, cutting, plating or other material forming process that
are known in the art; stacking the laminae together according to a
predetermined sequence. Each lamina may have separate parts which
are functionally connected by diffusive bonding, welding, weaving,
plating, bonding with inter-connective material, or any
inter-connective method, or combination of inter-connective method
and material forming process, or any combination thereof. The
laminae can be formed from laminated working materials. The series
of laminae can be connected in sequence, depending on the stacking
process, or not connected in sequence.
[0013] The stacking process can use a guide structure, which can be
integrated with the final product or not. Attachment is through
thermal, pressure, sonic, chemical driven process, or any
combination thereof. The attachment process can include additional
interfacial material, and occur at the same time or after the
stacking of some or all laminae.
[0014] In a first general aspect, a laminated heat transfer device
includes a base and a vane formed from a plurality of laminae. Each
lamina has a plurality of fins and a conduction core. The laminae
are stacked according to a predetermined sequence.
[0015] The laminated heat transfer device may include some or all
of the following features. The laminated heat transfer device also
includes at least one guide rod to guide the stacking of laminae.
The laminated heat transfer device also includes an alignment
fixture to guide the stacking of laminae.
[0016] The stacking of laminae includes folding a lamina upon
itself. Alternatively, the stacking of laminae includes piling a
lamina upon itself. In another alternative, the stacking of laminae
includes a combination of folding and piling a lamina.
[0017] The laminae are of equal size or varying size.
Alternatively, the laminae are shaped like spokes of a wheel. In
another alternative, at least one of the laminae is shaped like a
web.
[0018] The fins of the heat sink form a spiral. The heat sink is a
ducting-type heat sink.
[0019] In a second general aspect, a laminated heat transfer device
includes a base and a porous structure formed from a plurality of
first and second laminae. Each lamina has a plurality of shaped
openings. The laminae are stacked according to a predetermined
sequence.
[0020] The laminated heat transfer device may include some or all
of the following features. The stacking of laminae comprises
folding a lamina upon itself. Alternatively, the stacking of
laminae includes piling a lamina upon itself. In another
alternative, the stacking of laminae includes a combination of
folding and piling a lamina.
[0021] The first and second laminae are alternately stacked and the
laminae are stacked horizontally or vertically. The shaped openings
of each lamina are uniformly or non-uniformly spaced.
Alternatively, the shaped openings of each lamina are non-uniformly
sized. In another alternative, the shaped openings of each lamina
include the shapes of a rectangle, an oval, or a circle.
[0022] The laminae are of equal size or varying size. The laminated
heat transfer device is a heat sink. The heat sink is a porous-type
heat sink.
[0023] The laminated heat transfer device also includes two end
plates. The openings of the primary and secondary laminae are
different sizes in order to form grooves when the laminae are
stacked together. Alternatively, the primary and secondary laminae
are cut to form channels across the laminae toward the end plates
when the laminae are stacked together.
[0024] The laminated heat transfer device can also include two
plates. Each plate can be formed with a plurality of slits and
positioned before a respective end plate.
[0025] The laminated heat transfer device is a heat pipe.
[0026] The laminated heat transfer device also includes two end
plates. The openings of the primary and secondary laminae are the
same size in order to form grooves when the laminae are stacked
together. Alternatively, the primary and secondary laminae are cut
to form channels across the laminae toward the end plates when the
laminae are stacked together.
[0027] The laminated heat transfer device can also include two end
plates. Each plate can be formed with a plurality of slits and
positioned before a respective end plate.
[0028] The laminated heat transfer device is a heat pipe.
[0029] In a third general aspect, a laminated heat transfer device
includes a base and a plurality of laminae formed with
thermo-electric junctions. The laminae are stacked according to a
predetermined sequence wherein a first group of laminae are
attached to the base and a second group of laminae are thermally
isolated.
[0030] The laminated heat transfer device may include some or all
of the following features. The stacking of laminae includes folding
a lamina upon itself. Alternatively, the stacking of laminae
includes piling a lamina upon itself. In another alternative, the
stacking of laminae comprises a combination of folding and piling a
lamina.
[0031] The laminated heat transfer device is a split-body Peltier
device.
[0032] In other aspects, a laminated heat transfer device includes
combinations of ducting-type or porous-type laminated heat transfer
devices formed integrally with porous-type laminated heat transfer
device or split-body Peltier devices.
[0033] In another aspect, a method of producing a laminated heat
device includes specifying a three-dimensional structure as a
plurality of laminae, producing the laminae from sheets of working
material, stacking the laminae according to a predetermined
sequence with a guiding structure, and connecting the laminae.
[0034] The method of producing a laminated heat transfer device may
include some or all of the following. The stacking of laminae
includes folding a lamina upon itself. Alternatively, the stacking
of laminae includes piling a lamina upon itself. In another
alternative, the stacking of laminae includes a combination of
folding and piling a lamina.
[0035] The laminated heat transfer device is a heat sink.
Alternatively, the laminated heat transfer device is a heat
pipe.
[0036] In another general aspect, a laminated heat transfer device
includes a plurality of capillary structures formed from a
plurality of lamina. The laminae have geometric features. The
laminae are stacked according to a predetermined sequence.
[0037] The laminated heat transfer device may include some or all
of the following features. The laminated heat transfer device also
includes two end plates. Stacking the laminae includes folding
lamina upon itself. Alternatively, stacking the laminae includes
piling lamina upon itself. In another alternative, stacking the
lamina includes a combination of folding and piling lamina.
[0038] In another general aspect, a laminated heat transfer device
includes a plurality of capillary structures formed from a
plurality of lamina. The laminae are of different sizes. The
laminae are stacked according to a predetermined sequence.
[0039] The laminated heat transfer device may include some or all
of the following features. The laminated heat transfer device also
includes two end plates. Stacking the laminae includes folding
lamina upon itself. Alternatively, stacking the laminae includes
piling lamina upon itself. In another alternative, stacking the
laminae includes a combination of folding and piling lamina.
[0040] The details of one or more implementations are set forth in
the accompanying drawings and the description below. Other features
and advantages will be apparent from the description and drawings,
and from the claims.
BRIEF DESCRIPTION OF DRAWINGS
[0041] Exemplary implementations are depicted in the attached
figures, in which:
[0042] FIG. 1a illustrates an implementation of a laminated
ducting-type heat sink;
[0043] FIG. 1b is an exploded perspective view of an individual
lamina of FIG. 1a;
[0044] FIG. 1c shows illustrates an implementation of a laminated
ducting-type heat sink with cross-linkages;
[0045] FIG. 2a illustrates a laminated porous-type heat sink with
an integrated base;
[0046] FIG. 2b is a cross-sectional view of the porous structure of
FIG. 2a;
[0047] FIG. 2c is an exploded perspective view of an individual
lamina of FIG. 2a;
[0048] FIG. 2d is another exploded perspective view of the
individual lamina of FIG. 2a;
[0049] FIG. 2e is an exploded perspective view of an individual
lamina of a porous-type heat sink with varying pores;
[0050] FIG. 3a illustrates an implementation of a laminated
ducting-type heat sink for natural convection applications;
[0051] FIG. 3b is an exploded perspective view of an individual
lamina of FIG. 3a;
[0052] FIG. 4a illustrates a laminated heat-pipe;
[0053] FIG. 4b is an exploded perspective view of an individual
lamina of the laminated heat-pipe with an integrated wicking
structure;
[0054] FIG. 4c is an exploded perspective view of the laminated
heat-pipe with another integrated wicking structure;
[0055] FIG. 4d is a close-up view of laminae of the laminated
heat-pipe with a wicking structure;
[0056] FIG. 5a illustrates a laminated split-body Peltier
device;
[0057] FIG. 5b is an exploded perspective view of an individual
lamina of the device of FIG. 5a;
[0058] FIG. 6a illustrates an implementation of a porous heat sink
with an integrated heat-pipe;
[0059] FIG. 6b illustrates an implementation of a split-body
Peltier device with an integrated heat-pipe;
[0060] FIG. 6c illustrates a combination of a laminated heat pipe
and a laminated heat sink in which the cavity and capillary
structure extend from the base to the fins of the heat sink;
[0061] FIG. 6d illustrates another combination of a laminated heat
pipe and a laminated heat sink in which an additional extended
surface protrudes from the fins of the heat sink;
[0062] FIGS. 7a and 7b illustrate the implementation of the
laminated porous type heat sink of FIG. 2a in which the laminae are
folded to form the three-dimensional structure of the device;
and
[0063] FIGS. 7c and 7d illustrate the implementation of the
laminated heat pipe of FIG. 4a in which the laminae are folded to
form the three-dimensional structure of the device.
[0064] Like reference symbols in the various drawings indicate like
elements.
DETAILED DESCRIPTION
[0065] FIG. 1a illustrates an implementation of a laminated
ducting-type heat sink 100. Alternatively, the heat sink could have
a spiral-vane configuration. The heat sink 100 includes a base 110
and the vanes 130. The base 110 conducts heat from the source (not
shown), such as an electronic device, to the vanes 130. The base
110 is made out of thermally-conductive materials, such as copper,
and its thickness is a function of the applied heat-flux and the
airflow over the vanes. In general, the larger the applied
heat-flux, the thicker the base to spread the heat over the base.
Typically, the base 110 is approximately 5 mm.
[0066] FIG. 1b shows two guiding rods 111, which are functionally
attached to the base 110 through interference fitting, chemical
bonding, soldering, brazing, or any other similar techniques known
in the art. The guiding rods 111 are made of metals or polymers,
and guide the stacking of the laminae 120 through the guiding holes
121. Each lamina has fins 122 and a conduction core 123, so that
the heat conducts from the base 110 through the conduction core 123
toward the fins 122. As the conduction core 123 reduces the overall
thermal resistance, its diameter needs to be sufficiently large to
enable the heat to effectively diffuse from the base 110 to the
top-most lamina with minimal resistance. While the exact diameter
will depend on the flow rate impinging on the structure, the
diameter of the conduction core 123 is generally between 5 and 20
mm.
[0067] The fins 122 eject heat into the working fluid. The width of
the fins is generally less than 2 mm. The base of the fins 122 may
touch at the conduction core 123 or may be spaced apart. In
addition to ejecting heat, the fins 122 of the laminae 120 form the
vanes 130 of the final product 100 to provide radial ducting of the
working fluid. The laminae 120 may have similar or different
shapes, or depending on the final product 100. Each lamina 120 is a
thermal conductor and is preferably made from metal. The laminae
120 can be obtained by stamping, punching, etching, and/or plating
processes from sheets of working materials. The thickness of each
lamina is determined by the lamina production process. For example,
a stamping process is applied for copper material with a thickness
of approximately 1 mm or less. However, the thinner the working
material, the more laminae needed to complete a product. The
balance between tool-life, production rate, and product quality is
an operational issue determined on the production floor. In this
implementation, the laminae 120 are stacked and functionally joined
together to yield the final product 100. The joining between the
laminae 120 and with the base 110 can be accomplished with
soldering, brazing, welding, plating, chemical bonding, diffusion
bonding, or any similar process known in the art. The stacking
process can be performed through the aforementioned guiding rods
111 or through an alignment fixture (not shown). Furthermore, the
stacking and joining can be accomplished in one or multiple
processes.
[0068] Alternatively, the laminae are formed by a single lamina
that is then folded upon itself to form the three-dimensional
structure of the device. Laminae 120 formed of thermally conductive
materials, for example, copper or aluminum, are used in the folded
laminae implementation. Alternatively, the laminae are piled upon
each other to form the three-dimensional structure of the device.
Alternatively, a combination of folding and piling can be used to
form the three-dimensional structure of the device.
[0069] Another implementation of the laminated ducting-type heat
sink includes cross-linkages between the guiding vanes. As shown in
FIG. 1c, laminae 140 with cross-linkages 141 are introduced
periodically to render a structure that effectively utilizes the
space between the guiding vanes. These cross-linkages 141 increase
the number of heat conduction paths and the amount of convective
surface area.
[0070] FIG. 2a illustrates a laminated porous-type heat sink with
an integrated base. Heat sink 200 includes a base 210 and a porous
structure 220. As shown in FIG. 2b, the porous structure allows the
working fluid to pass through in three directions. As shown in FIG.
2c, this is obtained by stacking together primary laminae 221 and
secondary laminae 222 having different opening designs so that the
base 210 is formed as an integral part of the assembly 200.
Alternatively, the primary and secondary laminae 221, 222 can be
stacked perpendicular to the base (FIG. 2d). The openings in the
laminae are rectangular, but can be oval, circular, or other shape.
In addition, the openings on the individual laminae can be
spatially non-uniform to provide a heat sink with spatially varying
porosity (FIG. 2e). This configuration allows optimization of the
heat-conduction path relative to the fluid flow. In general, the
thickness, materials and process of stacking and joining the
laminae are similar to those described above.
[0071] Alternatively, the lamina is folded upon itself to form
laminae layers to form the device structure. In another
alternative, the laminae is piled upon itself to form the
three-dimensional structure of the device. Alternatively, a
combination of folding and piling can be used to form the
three-dimensional structure of the device.
[0072] One alternative, shown in FIG. 3a, is a laminated
ducting-type heat sink 300 for natural convection applications.
This heat sink 300 includes a base 310, an air intake 320, a
converging duct 330, guiding vanes 340 and a conduction rod 350. In
operation, a heat source (not shown) is applied to the bottom of
the base 310, which conducts the heat to the guiding vanes 340 and
the conduction rod 350. This conduction rod 350 should be
sufficiently large in diameter to allow heat to conduct upwards,
but sufficiently small to yield a large surface area to volume
ratio. In general, the conduction rod 350 is approximately 3 to 5
mm in diameter, and this rod may be straight or ribbed (not shown)
in order to maximize the heat transfer efficiency to the
surrounding air. The conduction rod 350 is situated directly above
the heat-source so most of the heat will travel up this conduction
rod 350 and to the adjacent air, which then rises due to the
buoyancy force. As the air rises, it is accelerated by the
converging duct 330, which then entrains air at the intake 320 by
creating a low-pressure condition. The guiding vanes 340 serve the
dual purpose of radially directing air inward, while conducting
heat from the base 310 to the converging duct 330, which further
heats the air and increases the flow-rate within. The converging
duct 330 should be a thermally conducting material, preferably a
metal, such as copper or aluminum. In addition, a fan (not shown)
can be placed on top of the heat sink to provide forced convective
cooling, in which case, the guiding vanes 340 also serve the
function of heat fins. As described above, the heat sink 300 is
obtained by stacking and joining together the inlet laminae 321 and
the duct laminae 331 as shown in FIG. 3b. By stacking together the
inlet laminae 321, the air intake 320 and the guiding vanes 340 are
created, and above these inlet laminae 321, the duct laminae 331
are stacked and functionally joined to render the converging duct
structure 330.
[0073] Alternatively, the lamina is folded upon itself to form
laminae layers to form the device structure. In another
alternative, the lamina is piled upon itself to form the
three-dimensional structure of the device. Alternatively, a
combination of folding and piling of the lamina can be used to form
the three-dimensional structure of the device.
[0074] In general, the thickness, materials and process of stacking
and joining the laminae are similar to those described above, with
the exception that the duct laminae 331 need to be thin to render a
smooth curvature. In general, such laminae are approximately 0.5 mm
in thickness, although thicker laminae can be accommodated by the
appropriate use of chamfers. As before, the stacking process can be
performed through guiding rods 311 or through an appropriate
alignment fixture (not shown).
[0075] Another implementation is the laminated heat-pipe shown in
FIG. 4a. This heat-pipe 400 includes alternately stacked primary
410 and secondary 420 laminae, and is terminated at the two ends by
the end plates 430. Alternatively, the lamina is folded upon itself
to form laminae layers to form the device structure. In another
alternative, the lamina is piled upon itself to form the
three-dimensional structure of the device. Alternatively, a
combination of folding and piling of the lamina can be used to form
the three-dimensional structure of the device.
[0076] Both the primary and secondary laminae 410, 420 have central
openings, and thus render these laminae, rings. The openings may be
rectangular, circular, oval, or other shape, and the amount of
material remaining in the laminae 411, 421 should be sufficient to
enable sealing between the laminae. In addition, the openings on
the primary and secondary laminae 410, 420 are slightly different
in size (approximately 0.2 to 1 mm) so that capillary grooves 440
are formed when the laminae are stacked together (FIG. 4b). These
capillary grooves 440 function as the wick and circulate condensed
liquid in the in-plane direction. The whole unit is sealed by
functionally joining the two laminae 410, 420 along with the end
plates 430. The sealing can be done after, during or before the
heat-pipe is charged with liquid, and in the case of the latter, a
valve (not shown) would be provided on the end plate. The sealing
process can be a pressure and/or temperature activated process
involving brazing, soldering, welding, chemical bonding, diffusion
bonding or any other similar methods known in the art.
[0077] To further improve on the circulation process, the primary
and secondary laminae 410, 420 include features 412, 422 that are
aligned to form capillary channels 450 across the laminae and
toward the two end plates 430, when the laminae are stacked
together. This is shown in FIG. 4c where the two additional plates
460 with slits can be added before the end plates 430 to improve
circulation. The capillary channels 450 should be sufficiently
small to enable flow, but not too small to prevent the accurate
alignment between the laminae. In general, these channels are
approximately 0.1 to 0.5 mm in diameter. In addition, the cuts, as
shown in FIG. 4d, can be increased (widened) to increase capillary
action in the channels. Finally, the thickness, materials and
process of stacking and joining the laminae are similar to those
described in the above implementation. Alternatively, as described
above, a combination of folding and piling the lamina can be used
to form the three-dimensional structure of the device.
[0078] Referring to FIG. 5a, a laminated split-body Peltier device
500 includes laminae 510 having thermoelectric junctions, such that
one group of junctions 511 is functionally attached to the base
520, while a second group of junctions 512 is thermally isolated by
distance to render a split-body configuration. In operation, group
512 is the hot junction, while group 511 is the cold junction.
Attachment to the base can be accomplished by a chemical agent
(curable adhesive), diffusive bonding, welding, soldering or any
similar methods known in the art. The base 515 can be a thermal
conductor and electrically insulated from the laminae 510 through
oxides or polymers (not shown). Each lamina is approximately 0.2 to
2 mm thick and can be formed from N-type and P-type materials in a
"Z" shape, obtained from sheets of dissimilar electrical conductors
(metallic or polymeric) through stamping, etching, plating, and/or
punching. Junctions 511, 512 can be formed by functionally joining
together the P-type 513 and N-type 514 materials through welding,
plating, soldering, diffusive bonding, and/or any other similar
methods known in the art.
[0079] With the exception of the two ends 516, each individual
lamina is electrically insulated by using an oxide or a polymer
coating (not shown) and are stacked/joined together similar to the
methods discussed for the first embodiment. The two ends 516 of
each lamina are not insulated to enable electric current to pass
through after the laminae are joined together. Two basic stacking
arrangements are possible depending on whether the individual
lamina is electrically connected in series or parallel. Electrical
wires 517 are then functionally attached to the two ends 516 for
connection with an external power source.
[0080] Alternatively, the stacking can be folding the lamina upon
itself to form laminae layers to form the device structure, or
piling the lamina upon itself, or a combination of folding and
piling the lamina.
[0081] The devices shown in FIGS. 1-5 can be combined together in
different ways to suit the final performance target. For example,
as shown in FIG. 6a, the laminated heat sink and the laminated
heat-pipe can be form one integral unit. Alternatively, the
laminated heat-pipe and the laminated split-body Peltier device can
form an integral unit (FIG. 6b). In another example, as shown in
FIG. 6c, a combination of a laminated heat pipe and a laminated
heat sink form an integrated heat pipe-heat sink device. The cavity
and capillary structure extend from the base to the fins of the
heat sink. Alternatively, the extended surface can protrude from
the fins, as shown in FIG. 6d.
[0082] Referring to FIGS. 7a-7d, the laminae are folded to form the
three-dimensional structure of the device.
[0083] A number of implementations have been described.
Nevertheless, it will be understood that various modifications may
be made. Accordingly, other implementations are within the scope of
the following claims.
* * * * *