U.S. patent application number 13/020382 was filed with the patent office on 2012-05-10 for heat dissipation structure.
Invention is credited to Ching-Tu WANG.
Application Number | 20120111538 13/020382 |
Document ID | / |
Family ID | 45076952 |
Filed Date | 2012-05-10 |
United States Patent
Application |
20120111538 |
Kind Code |
A1 |
WANG; Ching-Tu |
May 10, 2012 |
HEAT DISSIPATION STRUCTURE
Abstract
A heat dissipation structure mounted onto an electronic element
to dissipate heat. The heat dissipation structure includes a heat
absorber connected with the electronic element and a heat sink. The
heat absorber has a hollow first chamber to hold a working fluid.
The heat absorber and heat sink are interposed by a plurality of
first conduits. When the heat absorber absorbs heat generated by
the electronic element through a contact surface, the working fluid
held therein is vaporized into vapor. The vapor enters a second
chamber of the heat sink through the first conduits and performs
heat exchange with a cooling surface of the heat sink to be
converted into the working fluid again. The working fluid is
conveyed via a capillary structure in the second conduit to the
first chamber to form a thermal cycle. The structure of the
invention is simpler and can rapidly absorb and dissipate heat.
Inventors: |
WANG; Ching-Tu; (Taoyuan
County, TW) |
Family ID: |
45076952 |
Appl. No.: |
13/020382 |
Filed: |
February 3, 2011 |
Current U.S.
Class: |
165/104.21 |
Current CPC
Class: |
F28D 15/0266 20130101;
H01L 2924/0002 20130101; H01L 23/427 20130101; H01L 2924/00
20130101; H01L 2924/0002 20130101 |
Class at
Publication: |
165/104.21 |
International
Class: |
F28D 15/00 20060101
F28D015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 9, 2010 |
TW |
099221653 |
Claims
1. A heat dissipation structure for dissipating heat from an
electronic element, comprising: a heat absorber which includes a
contact surface connected to the electronic element and a hollow
first chamber to hold a working fluid, the heat absorber absorbing
heat generated by the electronic element through the contact
surface and transferring the heat to the working fluid to be
vaporized into vapor; a heat sink which includes a cooling surface
and a hollow second chamber; and a plurality of first conduits and
a second conduit that respectively communicate with the first
chamber and the second chamber, the vapor entering the second
chamber through the first conduits and being in contact with the
cooling surface to perform heat exchange to be condensed into the
working fluid again; the second conduit holding a capillary
structure to convey the condensed working fluid from the second
chamber to the first chamber to form a thermal cycle.
2. The heat dissipation structure of claim 1, wherein the capillary
structure is selected from the group consisting of sintered
powders, metal fibers, metal meshes, grooves and cotton
fabrics.
3. The heat dissipation structure of claim 1, wherein the cooling
surface of the heat sink is connected with a radiation fin.
4. The heat dissipation structure of claim 1, wherein the working
fluid is a refrigerant.
5. The heat dissipation structure of claim 1, wherein the working
fluid is selected from the group consisting of pure water,
methanol, ethanol, acetone and heptane.
6. The heat dissipation structure of claim 1, wherein the second
conduit includes two ends formed respectively a flow conduction
portion which is formed in a chamfer shape to facilitate flowing of
the working fluid into the second conduit.
7. The heat dissipation structure of claim 1, wherein the heat
absorber and the heat sink include respectively a plurality of
first coupling orifices and second coupling orifices to
respectively connect with the first conduits and the second
conduit.
8. The heat dissipation structure of claim 7, wherein the heat sink
includes an inclined wall inclined downwards from one edge thereof
towards the second coupling orifices.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a heat dissipation
structure and particularly to an improved heat dissipation
structure having a capillary structure.
BACKGROUND OF THE INVENTION
[0002] Advance of technology brings great benefits to people's life
and constantly enhances functionality and performance of electric
appliances. For instance, high-level electronic products stressed
on processing speed and reliability such as server and workstation,
and even personal computer and notebook computer, have promoted
higher performance and speed requirement for CPU. In such
developing trends, one of the biggest obstacles is heat generation.
At present, the most common cause of malfunction or damage of
electronic elements is poor heat dissipation that results in
overheating. Heat is mainly generated by active elements such as
transistors in IC during processing. The more transistors included
in chips, the greater heat generated. However, the size of
electronic products is shrunk constantly. With the chip area not
increased at the same time, heat dissipation area decreases
gradually and heat generation intensity increases. Conventional
heat dissipation modules cannot meet this requirement. Overheated
problem has become a bottleneck of electronic element technology
development.
[0003] Heat dissipation always is an important factor needed to be
taken into account in the design of an electronic system. The
purpose is to reduce the probability of malfunction or damage of
electronic elements caused by overheating. This not only enhances
the reliability of an electronic product, but also prolongs the
lifespan thereof. Research reports show that temperature increases
every 10-15.degree. C., the lifespan of chips will be shortened
50%. Hence how to rapidly dissipate the heat generated in the
electronic elements is one of the main subjects for research. Take
CPU in a computer for an example, the cooling method now adopted is
to install an air fan or heat sink on the CPU to directly dissipate
the heat. But the air fan employs compulsory convection for cooling
and creates many problems, such as power consumption, noise
generation and shorter lifespan. Thus other approaches have been
proposed such as using a heatpipe to transmit the heat generated by
the CPU to the heat sink or computer casing. Such passive cooling
approach has many advantages, such as less power consumption, no
noise generation and longer lifespan. Hence the heatpipe plays a
critical role in resolving the cooling problem of notebook
computers and other slim and light information products in the
future.
[0004] For instance, R.O.C. patent No. 1321644 discloses a heat
pipe cooling device which includes a heat pipe and a heat sink. The
heat pipe includes an evaporation section, a condensation section
and an insulation section bridging the evaporation section and
condensation section. The evaporation section is in contact with
the surface of a heating element that has a contact area
substantially the same as the surface area of the heating element.
The condensation section is connected to the heat sink. The
evaporation section and the insulation section are connected in a
tapered manner with a junction formed at a radius of curvature at a
ratio greater than 0.2 and smaller than or equal to 1 against the
width of the cross section of the insulation section.
[0005] The aforesaid conventional technique has a drawback that the
cooling capability thereof is restricted by the volume in the heat
pipe. As the smaller internal volume, the amount of working fluid
held therein is also less. The heat pipe is formed in a single pipe
so that it has slower cooling speed. Moreover, if the heat pipe is
applied to electronic elements with super high speed, it will
generate a greater amount of heat during operation and cannot
achieve the cooling requirement.
SUMMARY OF THE INVENTION
[0006] The primary object of the present invention is to solve the
disadvantage of undesirable cooling efficiency of the conventional
technique.
[0007] To achieve the foregoing object, the present invention
provides an improved heat dissipation structure adopted on an
electronic element to dissipate heat thereof. The heat dissipation
structure includes a heat absorber and a heat sink. The heat
absorber has a contact surface connected to the electronic element
to absorb heat generated thereon, and includes a hollow first
chamber to hold a working fluid for transferring heat. The heat
sink has a cooling surface and a hollow second chamber inside. The
heat absorber and heat sink are interposed by a plurality of first
conduits to connect the first chamber and second chamber. Heat
generated by the electronic element is absorbed by the heat
absorber through the contact surface. The working fluid held in the
first chamber is heated and vaporized into vapor flowing from the
first chamber via the first conduits to the second chamber. The
vapor performs heat exchange with the cooling surface in the second
chamber and converted into the working fluid again. The working
fluid flows back to the first chamber via a second conduit
containing a capillary structure inside to form a thermal cycle to
carry constantly the heat of the electronic element away.
[0008] By means of the second conduit having the capillary
structure, the working fluid can quickly flow back to the first
chamber to form a thermal cycle. The heat absorber and heat sink
have respectively the first chamber and second chamber that have
greater volume to hold more working fluid. The heat dissipation
structure of the invention thus formed is simpler and can dissipate
heat quickly.
[0009] The foregoing, as well as additional objects, features and
advantages of the invention will be more readily apparent from the
following detailed description, which proceeds with reference to
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view of the heat dissipation
structure of the invention.
[0011] FIG. 2 is an exploded view of the heat dissipation structure
of the invention.
[0012] FIGS. 3A and 3B are sectional views of the heat dissipation
structure of the invention in use conditions.
[0013] FIG. 4 is a sectional view of the capillary structure of the
invention using cotton strings in a use condition.
[0014] FIG. 5 is a perspective view of an embodiment of the
invention equipped with radiation fins.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Please refer to FIGS. 1 and 2, the present invention aims to
provide an improved heat dissipation structure 1 mainly adopted on
an electronic element 60 to dissipate heat thereof.
[0016] The heat dissipation structure 1 includes a heat absorber
10, a heat sink 20 and a plurality of first conduits 30 bridging
the heat absorber 10 and heat sink 20. The heat absorber 10 is
installed on the surface of the electronic element 60 to absorb
heat generated thereon. The heat absorber 10 is a hollow casing
containing a first chamber 12. The heat sink 20 also is a hollow
casing containing a cooling surface 21 and a second chamber 22 to
perform heat exchange. The heat absorber 10 and heat sink 20 have
respectively a plurality of first coupling orifices 13 and second
coupling orifices 23 to couple with the first conduits 30. Thus
forms the main structure of the invention.
[0017] Referring to FIGS. 3A and 3B, the heat absorber 10 is
mounted onto the electronic element 60 with a contact surface 11 to
absorb heat generated by the electronic element 60 during
operation. The first chamber 12 holds a working fluid 50 which may
be a refrigerant or liquid such as pure water, methanol, ethanol,
acetone or heptane in this embodiment, but not the limitation. When
the electronic element 60 is in operation and generates heat, the
contact surface 11 absorbs the heat from the electronic element 60
and transfers the heat to the working fluid 50 in the first chamber
12, and the temperature of the working fluid 50 rises. When the
temperature of the working fluid 50 is greater than the evaporation
point, the working fluid 50 is converted into vapor which enters
from the first chamber 12 through the first conduits 30 to the
second chamber 22 of the heat sink 20. The heat sink 20 is made of
a high heat conductive material, hence when the vapor enters the
second chamber 22 to contact with the cooling surface 21, the heat
carried by the vapor is rapidly absorbed by the cooling surface 21
and performs heat exchange with external air so that the vapor
temperature drops. When the vapor temperature drops to the
condensation point, the vapor is converted into the working fluid
50 again and attached to the inner walls of the heat sink 20.
[0018] Referring to FIG. 3B, the heat dissipation structure 1
further has a second conduit 40 containing a plurality of capillary
structures 41 which can be fine grooves, metal fibers, sintered
powders, metal meshes, or cotton fabrics or the like, but these are
not the limitations. Any capillary structure with adsorption
capability shall be included in the scope of the invention. The
second conduit 40 has two ends formed respectively a flow
conduction portion 42 which is formed in a chamfer shape to allow
the working fluid 50 to flow into the second conduit 40 more
smoothly. The condensed working fluid 50 flows along an inclined
wall 24 of the heat sink 20. The inclined wall 24 is inclined
downwards from one edge thereof towards the second conduit 40 so
that the working fluid 50 can quickly flow towards the second
conduit 40 to accelerate cycling speed. Moreover, the working fluid
50 is absorbed by the capillary structures 41 and flowed back to
the first chamber 12 to continuously absorb the heat generated by
the electronic element 60 to form a thermal cycle. Thereby the
electronic element 60 can be maintained at a desired working
temperature in regular conditions.
[0019] Please refer to FIG. 4 for an embodiment of the capillary
structures 41 which are made of cotton strings. The capillary
structures 41 made of the cotton strings are held in the second
conduit 40. When the vapor is condensed into the working fluid 50
in the second chamber 22, the working fluid 50 flows along the
inclined wall 24 towards the second conduit 40. The capillary
structures 41 absorb the working fluid 50 and convey it through the
second conduit 40 to the first chamber 12 to form the thermal
cycle.
[0020] To enhance cooling efficiency, the invention provides
another embodiment that includes a radiation fin 70 as shown in
FIG. 5. The radiation fin 70 is located on the cooling surface 21
of the heat sink 20 and made of a high heat dissipating material
such as aluminum or copper with a plurality of grooves formed on
the surface thereof. Such a structure not only can increase cooling
area, but also can channel air to circulate therein so that cooling
effect of the heat sink 20 can be further enhanced to improve the
cooling function of the invention.
[0021] As a conclusion, the invention provides the capillary
structures 41 in the second conduit 40 to rapidly convey the
working fluid 50 back to the first chamber 12 to continue the
thermal cycle. The structure of the invention is simpler and
cooling can be accomplished rapidly.
[0022] While the preferred embodiments of the invention have been
set forth for the purpose of disclosure, modifications of the
disclosed embodiments of the invention as well as other embodiments
thereof may occur to those skilled in the art. Accordingly, the
appended claims are intended to cover all embodiments which do not
depart from the spirit and scope of the invention.
* * * * *