U.S. patent application number 11/455727 was filed with the patent office on 2006-10-26 for heat sink.
This patent application is currently assigned to DELTA ELECTRONICS, INC.. Invention is credited to Yi-Sheng Lee.
Application Number | 20060237167 11/455727 |
Document ID | / |
Family ID | 34919207 |
Filed Date | 2006-10-26 |
United States Patent
Application |
20060237167 |
Kind Code |
A1 |
Lee; Yi-Sheng |
October 26, 2006 |
Heat sink
Abstract
A heat sink including a main body and a plurality of porous
structures is disclosed. The main body has a plurality of hollow
fins and a base. The fins and the base form a closed room. The
porous structures are set on the interior surfaces of different
fins, and are connected to the base. Each porous structure defines
a vapor chamber.
Inventors: |
Lee; Yi-Sheng; (Taoyuan
Hsien, TW) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
DELTA ELECTRONICS, INC.
|
Family ID: |
34919207 |
Appl. No.: |
11/455727 |
Filed: |
June 20, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11007192 |
Dec 9, 2004 |
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11455727 |
Jun 20, 2006 |
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Current U.S.
Class: |
165/104.26 |
Current CPC
Class: |
F28F 2215/06 20130101;
F28D 15/0233 20130101; F28D 15/046 20130101 |
Class at
Publication: |
165/104.26 |
International
Class: |
F28D 15/00 20060101
F28D015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 15, 2004 |
TW |
93106818 |
Claims
1. A heat sink, comprising: a main body having a plurality of
hollow fins and a base, each fin having a close end and an open end
facing the base, and the fins and the base forming a closed room;
and a plurality of porous structures comprising a plurality of
conductive portions, connective portions and heat-absorptive
portions, wherein the conductive portions are continuously formed
on the interior surfaces of the hollow fins, the heat-absorptive
portions are formed on the base, and each connective portion is set
between the neighboring conductive portions and connected to the
heat-absorptive portions on the base to divide the closed room into
a plurality of vapor chambers, and each connective portion
comprises a plurality of holes for allowing vaporized fluid to pass
therethrough.
2. The heat sink as described in claim 1, wherein the porous
structures are wicks selected from the group consisting of a
combination of one or more of mesh wicks, fiber wicks, sintered
wicks, and groove wicks.
3. The heat sink as described in claim 1, wherein the porous
structures contain a fluid selected from the group consisting of a
mixture of one or more of inorganic compounds, water, alcohols,
liquid metals, ketones, refrigerants, and organic compounds.
4. The heat sink as described in claim 1, wherein the material of
the porous structures is selected from the group consisting of a
mixture of one or more of plastics, metals, alloys, and porous
non-metal materials.
5. The heat sink as described in claim 1, wherein the fins and the
base are formed by a method selected from the group consisting of a
combination of one or more of soldering, engaging, embedding and
adhering, or the main body is one-piece molded.
6. The heat sink as described in claim 1, wherein the fins are
arranged in a longitudinal, parallel, transverse, diagonal, or
irregular array.
7. The heat sink as described in claim 1, wherein neighboring vapor
chambers are communicated with each other or in fluid communication
through the porous structures.
8. A heat dissipating device, comprising: a main body having a
plurality of hollow protrusions and a base, each protrusion having
a close end and an open end facing the base, and the protrusions
and the base forming a closed room; and a plurality of porous
structures comprising a plurality of conductive portions,
connective portions and heat-absorptive portions, wherein the
conductive portions are continuously formed on the interior
surfaces of the hollow protrusions, the heat-absorptive portions
are formed on the base, and each connective portion is set between
the neighboring conductive portions and connected to the
heat-absorptive portions on the base to divide the closed room into
a plurality of vapor chambers, and each connective portion
comprises a plurality of holes for allowing vaporized fluid to pass
therethrough.
9. The heat dissipating device as described in claim 8, wherein one
of the protrusions has a fin shape, columnar shape, lamellar shape,
conical shape, or lump shape.
10. The heat dissipating device as described in claim 8, wherein
the porous structures are wicks.
11. The heat dissipating device as described in claim 10, wherein
the wicks are selected from the group consisting of a combination
of one or more of mesh wicks, fiber wicks, sintered wicks, and
groove wicks.
12. The heat dissipating device as described in claim 8, wherein
the porous structures and the main body are assembled by sintering,
adhering, filling, or depositing.
13. The heat dissipating device as described in claim 8, wherein
the porous structures contain a fluid selected from the group
consisting of a mixture of one or more of inorganic compounds,
water, alcohols, liquid metals, ketones, refrigerants, and organic
compounds.
14. The heat dissipating device as described in claim 8, wherein
the material of the porous structures is selected from the group
consisting of a mixture of one or more of plastics, metals, alloys,
and porous non-metal materials.
15. The heat dissipating device as described in claim 8, wherein
the protrusions and the base are formed by soldering, engaging,
embedding or adhering, or the main body is one-piece molded.
16. The heat dissipating device as described in claim 8, wherein
neighboring vapor chambers are communicated with each other, or in
fluid communication through the porous structures.
17. The heat dissipating device as described in claim 8, wherein
the vapor chambers of the porous structures are arranged in the
closed room in a longitudinal, parallel, transverse, diagonal, or
irregular array.
18. A heat sink, comprising: a main body having a plurality of
hollow fins and a base, the fins and the base forming a closed
room; and a plurality of porous structures continuously formed on
the interior surfaces of the hollow fins and connected to the base,
wherein the porous structures further comprise a plurality of
connective portions, each connective portion is set between the
porous structures on neighboring hollow fins and connected to the
porous structures on the base to divide the closed room into a
plurality of vapor chambers, and each connective portion comprises
a plurality of holes for allowing vaporized fluid to pass
therethrough.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 11/007,192, filed Dec. 09, 2004, which claims
priority to Taiwan Application Serial Number 93106818, filed Mar.
15, 2004, the disclosure of which is hereby incorporated by
reference herein in its entirety.
BACKGROUND OF THE INVETION
[0002] a) Field of the Invention
[0003] The invention relates to a heat sink and, more particularly,
to a heat sink that is able to dissipate heat quickly and
efficiently.
[0004] b) Description of the Prior Art
[0005] With the advancement of electronic technology, the
electronic components are miniaturized and densely packaged.
However, this correspondingly produces more heat, and therefore
relying on natural or forced convection is insufficient to remove
heat.
[0006] The conventional method of removing heat generated from
electronic components is to conduct the heat from a heat source to
a heat sink and then to dissipate the heat to the surroundings
through natural or forced convection to the fins of the heat sink.
However, the conventional heat sinks with fins have some problems
that do affect the efficiency of heat removal. For instance, a
deficiency in temperature gradient due to the temperature
difference between the fin surfaces and the heat sink airflow being
only 5-10 degrees Celsius; the heat resistance problems due to the
material and structure of the heat sink and low fin efficiency that
is less than 70%. These problems are the root causes for the
conventional heat sinks not able to increase its' heat dissipation
efficiency and further unable to remove the heat produced by
electronic components sufficiently.
[0007] Thus, U.S. Pat. No. 6,490,160 has disclosed a heat sink
composed of a vapor chamber in view of the aforementioned problems.
The concept of this patent is to form a single vapor chamber in a
heat sink, wherein the top of the vapor chamber is composed of an
array of sheet tapered hallow pins deeply mounted in the heat sink
fins, and the bottom of the vapor chamber is a single chamber
connected to the bottom of all sheet tapered hollow pins. The heat
sink according to this patent dissipates heat by having a working
fluid to absorb heat and to be vaporized to the hollow pins and
then to be liquefied again after exchanging heat with the outer
surroundings. After the condensation, the working fluid (liquid)
flows along the groove wick structure on the surface of the hollow
pins and returns to the chamber from the outer wall.
[0008] Nonetheless, the path for the working fluid to return to the
chamber is long. Therefore, under a large heat-loading situation,
there may be no condensed liquid (working fluid) in the vapor
chamber and cause the chamber to dry out. In addition, the single
phase state (only vapor) in the heat conductive mechanism and the
long return path can make the fins except the outmost fins
ineffective. Under this condition, the effective dissipating
surface is greatly reduced and hence lowers the effectiveness of
the heat sink.
[0009] Moreover, another heat sink with vapor chamber has been
disclosed in US patent application serial number 2002/0118511. This
patent application also forms a single vapor chamber in the heat
sink, the chamber bottom is still a single chamber connected to all
hollow pin except that a matrix arrangement of the columnar hollow
pins is applied. This patent application utilizes a working fluid
to absorb heat in the chamber and to be vaporized to the hollow
pins. The vaporized working fluid then exchange heat with the
surroundings and condenses, and then trickles down along the
sidewall and back into the chamber due to gravity force. Since
gravity is the return-flow mechanism used in this application,
direction problems do exist. That is, when the installation
direction of the heat sink changes, the return-flow mechanism
becomes inoperable.
[0010] In regards to the foregoing statements, US patent
application 2002/0118511 also disclosed a method combining the two
technologies by forming a porous structure inside the hollow fins,
so that the working fluid can return to the chamber through the
porous structure by capillary force. However, this technology did
not solve the problem that exists in the U.S. Pat. No. 6,490,160,
where the dry out occurs and all but the outmost hollow fins are
inoperable under a high heat-loading condition, which lowers the
dissipation efficiency.
SUMMARY OF THE INVENTION
[0011] To solve the abovementioned problems, the present invention
discloses a heat sink with high heat dissipation efficiency under
any heat loading.
[0012] An object of the invention is to provide a heat sink with
high heat dissipation efficiency under high heat loadings.
[0013] Another object of the invention is to provide a heat sink
with high heat dissipation efficiency when installed in any
direction.
[0014] Yet another object of the invention is to provide a heat
sink which prevents dry outs and hot spots from occurring.
[0015] The invention discloses a heat sink including a main body
and a plurality of porous structures. The main body has a plurality
of hollow fins and a base, the fins and the base form a closed
room. The porous structures are set on the interior surfaces of a
different fin and are connected to the base, and each porous
structure defines a vapor chamber.
[0016] The invention also discloses a heat sink including a main
body and a plurality of porous structures with the main body having
a plurality of hollow protrusions and a base. The protrusions and
the base form a closed room. The porous structures are set on the
interior surfaces of a different protrusion and are connected to
the base, and each porous structure defines a vapor chamber.
[0017] The porous structures are wick structures; common wick
structures include mesh, fiber, sintered, groove wicks, or
combinations thereof. The porous structures and the main body are
assembled by methods such as sintering, adhering, filling, or
depositing. The material of the porous structures includes
plastics, alloys or metals such as copper, aluminum, iron, porous
non-metallic materials and mixtures thereof. The porous structures
contain a working fluid; the working fluid can be inorganic
compounds, water, alcohols, liquid metals such as mercury, ketones,
refrigerants such as HFC-134a, other organic compounds or mixtures
thereof.
[0018] The main body can be one-piece molded or composed of several
components. The components are bind together by soldering,
engaging, embedding, adhering, or combinations thereof. Neighboring
vapor chambers are communicated with each other directly, or
indirectly in fluid communication through the porous
structures.
[0019] The vapor chambers are arranged in the closed room either in
an array arrangement, a longitudinal arrangement, a parallel
arrangement, or a transverse arrangement.
[0020] Since the heat sink according to the invention utilizes wick
structures (porous structures) to form several small vapor chambers
and/or small sectors, the wick structure of every protrusion forms
an independent heat-removal cycle. So, under high heat-loading
situation, the dry outs will not occur and the high heat
dissipation efficiency is maintained.
[0021] Moreover, since the bottom of the small vapor chambers
and/or small sectors are composed of connecting wicks
(heat-absorptive portion), the working fluid in each small vapor
chamber are in fluid communication, and thus the possibility of hot
spots occurring is lowered, and the heat is evenly distributed to
each small vapor chamber and/or small sector.
[0022] Furthermore, since the return-flow mechanism of the heat
sink according to the invention uses capillary force but not simply
relies on gravity, the return-flow speed of the working fluid in
the heat sink will not be affected by the direction for
installation.
[0023] The vapor chamber in the heat sink according to the
invention is composed of a plurality of small vapor chambers and/or
small sectors, and therefore the return-flow path of the working
fluid is short, and the return-flow speed and heat dissipation
efficiency are enhanced.
[0024] The foregoing and other objectives, features, and advantages
of the invention will be more readily understood upon consideration
of the following detailed description of the invention, taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a schematic diagram of a preferred embodiment of a
heat sink in accordance with the invention;
[0026] FIG. 2 is an enlarged partial view of the preferred
embodiment of FIG. 1; and
[0027] FIG. 3 illustrates the vapor flow in the preferred
embodiment of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0028] Referring to FIG. 1, a heat sink 100 includes a main body
102 and a plurality of porous structures 110 inside the main body
102, wherein the main body 102 has a closed room 124 formed
therein.
[0029] The main body 102 has a plurality of hollow protrusions 120
and a base 122 connecting to a heat source 118. The shape and/or
size of the base 122 varies in accordance with the placement of the
protrusions 120 and the shape of the heat source 118. Each
protrusion 120 is hollow and has two ends; the end proximate the
base 122 has an opening and the other end is closed. The
protrusions 120 are in a shape of fin, column, lamella, cone, or
lump; and in a form of curve, arch, slant, vertical, or any other
form. The protrusions 120 and the base 122 of the main body 102 can
be one-piece molded or jointed by soldering, engaging, embedding,
adhering, or a combination of any of the methods listed thereof.
Moreover, the closed room 124 can be divided into a plurality of
vapor chambers 112 by the porous structures 110.
[0030] The porous structures 110 are embedded on the interior
surfaces of the main body 102, and are sealed therein. The porous
structures 110 form a plurality of vapor chambers 112 in the main
body 102. Each porous structure 110 is sectioned into a conductive
portion 104 and a connective portion 106, and a heat-absorptive
portion 108. The porous structures 110 are for absorbing working
fluid; the condensed working fluid flows through the conductive
portion 104, the connective portion 106, and into the
heat-absorptive portion 108. The working fluid is of inorganic
compounds, water, alcohols, liquid metals such as mercury, ketones,
refrigerants such as HFC-134a, other organic compounds, or a
mixture of any of the fluids listed thereof. Using the pressure in
the vapor chambers 112 can control the boiling temperature of the
working fluid. The heat-absorptive portion 108 set on the interior
surfaces of the base 122 is for absorbing the working fluid. The
conductive portion 104 set on the interior surfaces of the
protrusion 120 is for conducting the condensed working fluid to the
heat-absorptive portion 108. The other connective portion 106 is
set between the heat-absorptive portion 108 and the conductive
portion 104, and connected to both portions.
[0031] The conductive portion 104, the connective portion 106 and
the heat-absorptive portion 108 can be made of material such as
copper, aluminum, iron, other metals and/or alloys, plastics, other
porous non-metallic materials, or a mixture of any of the materials
listed thereof. The conductive portion 104, the connective portion
106 and the heat-absorptive portion 108 are required to have a
porous formation such as wicking structures. Common wicking
structures include mesh wicks, fiber wicks, sintered wicks, groove
wicks, or other structures including a combination of any of the
wicking structures listed thereof. The porous structures 110 and
the main body 102 are assembled by sintering, adhering, filling, or
depositing.
[0032] The connective portion 106 106 is set between neighboring
protrusions 120 so that the working fluid in the conductive portion
104 can flow quickly to the heat-absorptive section 108 along the
connective portion 106. The connective portion 106 divides the
closed room 124 into a plurality of vapor chambers 112; each vapor
chamber 112 corresponds to at least one of the protrusions 120. The
connective portion 106 can also divide the closed room 124 into a
plurality of sectors; the sectors each corresponds to a protrusion
120 and the neighboring sectors are communicated with each other.
The vapor chambers 112 or the small sectors can be disposed in
array, parallel, longitudinal, transverse, diagonal or irregular
arrangements.
[0033] Although the closed room 124 has been divided into a
plurality of vapor chambers 112 and/or small sectors by the
connective portions 106, the working fluid in the heat-absorptive
portion 108 on the bottom of each vapor chamber is in fluid
communication with other vapor chambers. Thus the occurred
probability of the partial hot spots on the heat sink 100 is
reduced, and the heat is distributed evenly on the bottom of the
heat sink 100.
[0034] The heat sink 100 described above is used to illustrate the
heat-removal mechanism used in the invention. In this embodiment,
the base 122 of the heat sink 100 is installed on the heat source
118, wherein the heat source 118 is composed of a heat-generating
element 116 and a conducting structure 114 connected to the
heat-generating element 116. The conducting structure 114 can be a
heat-dissipating paste, or a phase-changing metal sheet; the
heat-generating element 116 can be a computer-processing unit
(CPU), or a semi-conductor chip. For illustration purpose, the
protrusions 120 exemplify a fin shape in this embodiment.
[0035] When the bottom of the vapor chambers 112 is heated and the
temperature of the working fluid raises to the boiling point, the
working fluid in the heat-absorptive portions 108 boils and
evaporates, causing the pressure in the vapor chambers 112 to rise
and the vapors move towards the fins quickly. The heat in the fins
is then dissipated by natural or forced convection; the vapors
condensate into liquid on the interior surfaces of the fins and the
working fluid (liquid) penetrates into the conductive portions 104
(wick structure) in the fins. Since the heat-absorptive portions
108 (wick structure) are drier than the conductive portions 104,
the capillary force drives the working fluid (liquid) to flow back
to the bottom of the vapor chambers 112 and hence a heat-removal
cycle is completed.
[0036] Since the bottom edges of the fins are connected to the base
122 with the connective portions 106 (wick structure), the
return-flow speed of the working fluid is enhanced and dry out is
prevented from occurring.
[0037] Referring to FIG. 2, the section "A" of the partial view of
the connective portion 106 is enlarged to show the detailed
structure thereof. The connective portion 106 further includes a
plurality of holes 210 thereon for evenly distributing the
vaporized fluid in the vapor chambers 112. Therefore, the vaporized
fluid in the vapor chambers 112 can quickly and uniformly
distribute in the vapor chambers 112.
[0038] Referring to FIG. 3, the vapor can easily flow to the
adjacent vapor chambers 112 along the arrow signs 312 and to the
protrusion 120 along the arrow signs 310.
[0039] Concluding from the description above, the heat sink
according to the invention utilizes wick structures (porous
structures) to form a plurality of small vapor chambers and/or
small sectors, so that the wick structure in each protrusion forms
an independent heat-removal cycle. Thus even under high
heat-loading situations, dry outs caused by the lack of working
fluid will not occur and the heat-dissipating effect can be
maintained. In addition, the connective portions include a
plurality of holes so that the vapor in the vapor chambers is
uniformly distributed. Hence, the heat can be more smoothly
distributing in the heat sink.
[0040] Moreover, the bottom of the small vapor chambers and/or
small sectors are made of connecting wick structures
(heat-absorptive portions), thereby the working fluid in each small
vapor chamber and/or small sector is in fluid communication via the
wick structures on the bottom. This in turn lowers the occurred
probability of hot spots and the heat is evenly distributed to each
small vapor chamber and/or small sector.
[0041] Furthermore, since the heat sink according to the invention
utilizes capillary force in the return-flow mechanism instead of
simply relying on gravity, thus the installation direction of the
heat sink will not affect the return-flow speed.
[0042] In addition, since the vapor chamber of the heat sink
according to the invention includes a plurality of small vapor
chambers and/or small sectors, each small vapor chamber and/or
small sector has shorter return-flow path than that of the
conventional technology. Therefore, the return-flow speed of the
working fluid is increased and the heat-dissipating effect is
enhanced.
[0043] While the invention has been described by way of example and
in terms of the preferred embodiment, it is to be understood that
the invention is not limited to the disclosed embodiments. To the
contrary, it is intended to cover various modifications and similar
arrangements as would be apparent to those skilled in the art.
Therefore, the scope of the appended claims should be accorded the
broadest interpretation so as to encompass all such modifications
and similar arrangements.
* * * * *