U.S. patent application number 10/559042 was filed with the patent office on 2006-07-20 for cooling device of thin plate type for preventing dry-out.
Invention is credited to Jae Joon Choi, Chang Ho Lee, Jeong Hyun Lee, Jihwang Park.
Application Number | 20060157227 10/559042 |
Document ID | / |
Family ID | 36659730 |
Filed Date | 2006-07-20 |
United States Patent
Application |
20060157227 |
Kind Code |
A1 |
Choi; Jae Joon ; et
al. |
July 20, 2006 |
Cooling device of thin plate type for preventing dry-out
Abstract
The present invention provides a thin plate type cooling device
including at least one cavity formed on an inside wall of coolant
circulation loop in order to prevent dry-out of the coolant.
Inventors: |
Choi; Jae Joon;
(Seongnam-si, KR) ; Park; Jihwang; (Seoul, KR)
; Lee; Jeong Hyun; (Gwacheon-si, KR) ; Lee; Chang
Ho; (Seoul, KR) |
Correspondence
Address: |
THELEN REID & PRIEST, LLP
P. O. BOX 640640
SAN JOSE
CA
95164-0640
US
|
Family ID: |
36659730 |
Appl. No.: |
10/559042 |
Filed: |
October 28, 2003 |
PCT Filed: |
October 28, 2003 |
PCT NO: |
PCT/KR03/02281 |
371 Date: |
November 29, 2005 |
Current U.S.
Class: |
165/104.21 ;
165/104.26; 257/E23.088 |
Current CPC
Class: |
H01L 23/427 20130101;
H01L 2924/0002 20130101; F28F 2270/00 20130101; F28D 15/0233
20130101; F28F 2245/04 20130101; H01L 23/473 20130101; H01L 2924/00
20130101; H01L 2924/0002 20130101; F25B 2339/021 20130101; F28F
2245/02 20130101; F28D 15/0266 20130101; H01L 2924/3011 20130101;
B82Y 30/00 20130101; F28F 3/12 20130101 |
Class at
Publication: |
165/104.21 ;
165/104.26 |
International
Class: |
F28D 15/00 20060101
F28D015/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 31, 2003 |
KR |
10-2003-0035078 |
Claims
1. A thin plate-type cooling device comprising: a thin plate-shaped
housing in which a circulation loop of a fluid is formed; and a
coolant capable of changing from one state to another, circulating
along said circulation loop inside said housing, wherein said
circulation loop inside said housing comprises: an evaporation
section formed on one end of said circulation loop, wherein said
liquefied coolant is at least partly filled by a capillary action
and said coolant filled in a liquid state is gasified by heat
transferred from an external heat source; a gaseous coolant
transfer section formed adjacent to said evaporation section,
wherein said gasified coolant is transferred through said gaseous
coolant transfer section and said gaseous coolant transfer section
has at least one first cavity for containing said gaseous coolant
which has not been condensed; a liquefied coolant transfer section
formed adjacent to said condensation section and thermally
insulated from said evaporation section, wherein said liquefied
coolant is transferred towards said evaporation section; and a
thermal insulation section for thermally insulating said
evaporation section from at least a part of said liquefied coolant
transfer section.
2. A thin plate-type cooling device as claimed in claim 1, wherein
at least a part of said liquefied coolant transfer section
comprises a liquefied coolant storage section for storing said
coolant in the liquid state.
3. A thin plate-type cooling device as claimed in claim 2, wherein
at least a part of said liquefied coolant transfer section
comprises a plurality of liquefied coolant storage sections.
4. A thin plate-type cooling device as claimed in claim 2, wherein
said liquefied coolant storage section comprises a tiny channel of
which surface tension is set to be more than gravity.
5. A thin plate-type cooling device as claimed in claim 1, wherein
a cross-section of a tiny channel of said evaporation section
and/or said liquefied coolant transfer section becomes small from
said liquefied coolant transfer section contacting said
condensation section to said evaporation section contacting said
gaseous coolant transfer section.
6. A thin plate-type cooling device as claimed in claim 1, wherein
said condensation section has at least one second cavity.
7. A thin plate-type cooling device as claimed in claim 1, wherein
said liquefied coolant transfer section has at least one third
cavity.
8. A thin plate-type cooling device as claimed in claim 1, wherein
hydrophilic treatment is performed on surfaces of said liquefied
coolant transfer section and said evaporation section, and
hydrophobic treatment is performed on surfaces of said gaseous
coolant transfer section and said condensation section.
Description
TECHNICAL FIELD
[0001] The present invention relates to a thin plate-type cooling
device for cooling a semiconductor integrated circuit device, etc.,
and more particularly to a thin plate-type cooling device capable
of preventing a coolant from drying out using the phase transition
of operation fluid.
BACKGROUND ART
[0002] As design rules decrease due to the trend towards large
scale integration of semiconductor devices, and thereby the line
width of electronic devices constituting semiconductor devices
narrows, small-sized and high performance electronic equipment has
been achieved owing to a larger number of transistors per unit
area, which causes, however, that the ratio of heat emission of a
semiconductor device per unit area increases. The increase of the
rate of heat emission deteriorates the performance of semiconductor
devices and lessens the life expectancy thereof, and eventually
decreases the reliability of a system adopting semiconductor
devices. Particularly in semiconductor devices, parameters are too
easily affected by operation temperatures, and thereby it further
deteriorates the characteristics of integrated circuits.
[0003] In response to the increase of the rate of heat emission,
cooling technologies have been developed such as fin-fan, peltier,
water-jet, immersion, heat pipe type coolers, etc., which are
generally known.
[0004] The fin-fan type cooler which compulsorily cools devices
using fins and/or fans has been used for tens of years, but has
some defects such as noise, vibration, and low cooling efficiency
as compared with its large volume. Although the peltier type cooler
doesn't make noise or vibration, it has a problem that it requires
too many heat dissipation devices at its hot junction, needing
large driving power due to its low efficiency.
[0005] The water-jet type cooler goes mainstream in cooling device
research because of its excellent efficiency, but its structure is
complicated due to the use of a thin film pump driven by an
external power supply, and it is significantly affected by gravity,
as well as a problem that it is difficult to achieve robust design
when applied to personal mobile electronic equipment.
[0006] And in the cooling device using a heat pipe, since the
flowing directions of gas and fluid inside a pipe are opposite each
other, the gas flowing from an evaporation section towards a
condensation section acts as resistance against the fluid returning
from the condensation section towards the evaporation section.
Accordingly, if a large amount of heat is applied to the heat pipe,
the liquid into which the gas with a high velocity is to change
cannot return to the evaporation section, so a dry-out phenomenon
by which the coolant in the liquid state is exhausted occurs in the
evaporation section. And there is a problem that its installation
location is significantly restricted because the coolant gasified
inside the pipe moves depending upon buoyancy and pressure
difference, and the liquefied coolant in the heat pipe depends on
gravity due to the structure and size of the medium of the
returning section.
[0007] In order to solve the above problem, it has been disclosed
in Korea Patent Application No. 2001-52584, "A thin plate-type
cooling device", by the applicant of this invention that the
cooling performance of a small-sized thin plate-type cooling device
is hardly affected by gravity and the coolant is naturally
circulated without any external power supply. The thin plate-type
cooling device disclosed includes a thin plate-shaped housing
having a fluid circulation loop therein and a coolant having a
phase transition characteristic, circulating the circulation loop
in the housing, wherein the circulation loop in the housing
includes: a coolant storage section formed on one end inside the
housing for storing the coolant in the liquid state; an evaporation
section including at least one first tiny channel connected to the
one end of the coolant storage section, wherein the coolant in the
liquid state in the first tiny channel is partly filled from the
coolant storage section to a predetermined area of the first tiny
channel due to the surface tension with an inner wall of the first
tiny channel, the surface tension inside the first tiny channel is
set more than gravity, and the coolant in the liquid state filled
in the first tiny channel can be gasified by the heat absorbed from
a heat source; a condensation section including at least one second
tiny channel disposed away from the first tiny channel of the
evaporation section as much as a predetermined distance in the
longitudinal direction on a same plane for condensing the coolant
in the gas state gasified and transferred from the first tiny
channel, wherein the surface tension between an inner wall of the
second tiny channel and the coolant condensed is set more than
gravity; a gaseous coolant transfer section disposed between the
first tiny channel of the evaporation section and the second tiny
channel of the condensation section; and a liquefied coolant
transfer section separated from the gaseous coolant transfer
section for transferring the coolant in the liquid state condensed
in the condensation section towards the coolant storage
section.
[0008] According to the thin plate-type cooling device disclosed,
as the coolant circulating around the circulation loop inside the
housing changes its phase between liquid and gas states, the heat
of the external heat source contacting the cooling device can be
dissipated using the latent heat during phase transition.
[0009] According to the thin plate-type cooling device disclosed,
however, there is a possibility that the coolant in the gas state
is not completely condensed in the condensation section and reaches
the condensation section via the liquefied coolant transfer section
and/or the coolant storage section, contained in the condensed
coolant in the form of bubbles. If the bubbles contained in the
coolant in the liquid state reach the evaporation section, there is
concern that the dry-out phenomenon by which the coolant in the
liquid state is exhausted occurs in the evaporation section.
DISCLOSURE OF INVENTION
[0010] In order to solve the problems above, it is an object of the
present invention to provide a thin plate-type cooling device for
preventing the dry-out phenomenon in the evaporation section.
[0011] Moreover, it is another object of the present invention to
provide a thin plate-type cooling device wherein its cooling
efficiency is increased by improving the flow of the coolant.
[0012] In order to achieve the objects above, a thin plate-type
cooling device includes a thin plate-shaped housing in which a
circulation loop of a fluid is formed, and a coolant capable of
changing from one state to another, circulating along the
circulation loop inside the housing, wherein the circulation loop
inside the housing includes an evaporation section formed on one
end of the circulation loop, wherein the liquefied coolant is at
least partly filled by a capillary action and the coolant filled in
a liquid state is gasified by heat transferred from an external
heat source, a gaseous coolant transfer section formed adjacent to
the evaporation section, wherein the gasified coolant is
transferred through the gaseous coolant transfer section and the
gaseous coolant transfer section has at least one first cavity for
containing the gaseous coolant which has not been condensed, a
liquefied coolant transfer section formed adjacent to the
condensation section and thermally insulated from the evaporation
section, wherein the liquefied coolant is transferred towards the
evaporation section, and a thermal insulation section for thermally
insulating the evaporation section from at least a part of the
liquefied coolant transfer section.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1a shows the external appearance of a thin plate-type
cooling device according to a first embodiment of this
invention.
[0014] FIG. 1b shows a schematic section on an X-Y plane of the
thin plate-type cooling device of the first embodiment viewed in a
second direction.
[0015] FIG. 2a shows a schematic sectional view taken in the first
direction on the X-Y plane of the thin plate-type cooling device of
the first embodiment.
[0016] FIG. 2b shows a schematic sectional view taken along the
A-A' line on the Y-Z plane of the thin plate-type cooling device of
the first embodiment.
[0017] FIG. 2c shows a schematic sectional view taken along the
B-B' line on the Y-Z plane of the thin plate-type cooling device of
the first embodiment.
[0018] FIG. 3a shows a schematic sectional view taken in the first
direction on the X-Y plane of a thin plate-type cooling device of a
second embodiment.
[0019] FIG. 3b shows a schematic sectional view taken along the
A-A' line on the Y-Z plane of the thin plate-type cooling device of
the second embodiment.
[0020] FIG. 3c shows a schematic sectional view taken along the
B-B' line on the Y-Z plane of the thin plate-type cooling device of
the second embodiment.
[0021] FIG. 4a shows a schematic sectional view taken in the first
direction on the X-Y plane of a plate-type cooling device of a
third embodiment.
[0022] FIG. 4b shows a schematic sectional view taken along the
A-A' line on the Y-Z plane of the thin plate-type cooling device of
the third embodiment.
[0023] FIG. 4c shows a schematic sectional view taken along the
B-B' line on the Y-Z plane of the thin plate-type cooling device of
the third embodiment.
[0024] FIG. 5a shows a schematic sectional view taken in the first
direction on the X-Y plane of a thin plate-type cooling device of a
fourth embodiment.
[0025] FIG. 5b shows a schematic sectional view taken along the
A-A' line on the Y-Z plane of the thin plate-type cooling device of
the fourth embodiment.
[0026] FIG. 5c shows a schematic sectional view taken along the
B-B' line on the Y-Z plane of the thin plate-type cooling device of
the fourth embodiment.
[0027] FIG. 5d shows a schematic sectional view taken along the
C-C' line on the Y-Z plane of the thin plate-type cooling device of
the fourth embodiment.
BEST MODE FOR CARRYING OUT THE INVENTION
[0028] Hereinafter, the exemplary embodiments of the present
invention will now be described in detail, referring to attached
drawings.
[0029] Referring to FIG. 1a, first, FIG. 1a shows the external
appearance of a thin plate-type cooling device 100 according to a
first embodiment of this invention. It is preferable that the
external appearance of the thin plate-type cooling device 100 of
this invention is approximately rectangular, and the thin
plate-type cooling device 100 is formed by bonding a lower plate
100a and an upper plate 100b in each of which internal elements
have been formed.
[0030] For the sake of understanding and description, it is defined
that, as shown in FIG. 1a, an "X-axis direction" is the
longitudinal direction (from the left to the right of the drawing)
of the thin plate-type cooling device 100 of this invention, a
"Y-axis direction" is the lateral direction (into the drawing) of
the thin plate-type cooling device 100, and a "Z-axis direction" is
the vertical direction (from the bottom of the top of the drawing)
of the thin plate-type cooling device 100. Moreover, it is also
defined that a "section viewed in a first direction" is the section
viewed in the negative Z-axis direction (i.e., the direction from
the bottom of the top of the drawing), and a "section viewed in a
second direction" is the section viewed in the positive Z-axis
direction (i.e., the direction from the top of the bottom of the
drawing).
[0031] Referring to FIG. 1b, FIG. 1b shows a schematic section on
an X-Y plane of the thin plate-type cooling device 100 of the first
embodiment viewed in the second direction. As shown in the drawing,
the lower plate 100a of the thin plate-type cooling device 100
forms a circulation loop of a coolant inside an approximately
rectangular housing 112 by being combined with the upper plate
100b. The coolant circulates in the arrow direction and cools an
external heat source contacting the cooling device 100, using the
latent heat during its phase transition between liquid and gas
states.
[0032] The housing 112 can be manufactured of a material such as
semiconductor, e.g. Si, Ga, etc., a novel substance-laminated
material, e.g. Self Assembled Monolayer (SAM), metal and/or alloy,
e.g. Cu, Al, etc. with high conductivity, ceramic, a high molecular
substance, e.g. plastic, a crystalline material, e.g. diamond.
Particularly, in case of a semiconductor chip as the external heat
source, the housing can be made of the same material as that of the
surface of the external source so as to minimize the thermal
contact resistance. In case that the thin plate-type cooling device
100 is made of semiconductor, the housing can be integrally formed
as one piece with the surface material of the external source
during the process of manufacturing the semiconductor chip.
[0033] Next, the coolant to be injected into the thin plate-type
cooling device 100 can be selected from things capable of changing
its phase between liquid and gas states due to the external heat.
In this embodiment, it is preferable to use water whose latent heat
and surface tension are high as the coolant, because it is
desirable not to use any of a series of CFC as the coolant in
consideration of environmental pollution.
[0034] In addition, since the surface tension between the coolant
and an inner wall of the thin plate-type cooling device 100 varies
depending upon the material of the housing, a suitable coolant
should be selected. For example, any of a series of alcohol such as
methanol, ethanol, etc., may be used as the coolant besides water.
In case of water or alcohol as the coolant, it has an advantage
that a large amount of heat can transferred because its heat
capacity is large, and its contact angle by the surface tension
with the inner wall of semiconductor is small, so that the current
speed of the coolant becomes high. Moreover, water or alcohol as
the coolant, unlike CFC, does not cause any environmental pollution
even though it leaks from the thin plate-type cooling device 100 by
any reason.
[0035] The selection of the coolant is merely of an optional matter
for the implementation of this invention, which does not limit the
technical scope of this invention.
[0036] As shown in the drawing, the thin plate-type cooling device
100 includes an evaporation section 104 formed on one end inside
the thin plate-type cooling device 100, in which the coolant in the
liquid state is at least partly filled due to the capillary action
and the coolant in the liquid state filled is gasified due to the
heat transferred from the external heat source, a gaseous coolant
transfer section 106 formed adjacent to the evaporation section
104, in which the coolant gasified is transferred in a
predetermined direction due to the pressure difference, a
condensation section 108 formed adjacent to the gaseous coolant
transfer section 106, in which the coolant in the gas state is
condensed into the liquid state, and liquefied coolant transfer
sections 102 and 110 formed adjacent to the condensation section
108 and thermally insulated from the evaporation section 104, in
which the coolant condensed into the liquid state is transferred
towards the evaporation section 104.
[0037] The evaporation section 104, the gaseous coolant transfer
section 106, the condensation section 108 and the liquefied coolant
transfer sections 102 and 110 may be formed only on the lower plate
100a of the thin plate-type cooling device 100. Moreover, the upper
plate 100b of the thin plate-type cooling device 100 may have only
cavities on predetermined areas. The configuration of the upper
plate 100b will be described later referring to FIGS. 2 to 5.
[0038] The coolant inside the thin plate-type cooling device 100
forms the circulation loop along the arrows of the drawing. That
is, the coolant sequentially circulates via the evaporation section
104, the gaseous coolant transfer section 106, the condensation
section 108, the liquefied coolant transfer section 110 near the
condensation section, and the liquefied coolant transfer section
102 near the evaporation section.
[0039] Alternatively, the thin plate-type cooling device 100 may
further include a coolant storage section (not shown) whose volume
is suitable for storing a predetermined amount of the coolant in
the liquid state in the liquefied coolant transfer sections 102 and
110. For example, a part of the liquefied coolant transfer section
102 near the evaporation section may be used for the coolant
storage section. In addition, a plurality of coolant storage
sections may be formed.
[0040] The evaporation section 104 is adjacent to one end ("exit
side") of the liquefied coolant transfer section 102 near the
evaporation section, and a plurality of tiny channels are formed in
the evaporation section 104, so that all or a part of the tiny
channels are filled with the coolant stored in the liquefied
coolant transfer section 102 near the evaporation section by the
capillary action. In addition, the evaporation section 104 is
disposed adjacent to the external heat source (not shown), and
thereby the coolant in the liquid state accumulated in the tiny
channels by the heat transferred form the heat source is gasified,
so it changes into the gaseous state. Accordingly, the heat from
the heat source is absorbed to the coolant as much as the latent
heat caused by the phase transition of the coolant, and the heat
from the heat source can be eliminated as the coolant in the gas
state is condensed to dissipate the heat as described later.
[0041] It is preferable that the surface tension in the tiny
channels is larger than gravity. In addition, the smaller the
contact angle of the meniscus of the liquefied coolant accumulated
in the tiny channels, the more it is preferable. In order to do so,
it is preferable that the inner walls of the tiny channels is
formed of or treated with a hydrophilic material. For example, the
hydrophilic material treatment is performed by plating, coating,
coloring, anodization, plasma treatment, laser treatment, etc. In
addition, the surface coarseness of the inner walls of the tiny
channels can be adjusted in order to improve the heat transfer
efficiency.
[0042] Meanwhile, besides the tiny channels of the evaporation
section 104, it is preferable that the hydrophilic treatment is
performed on the surfaces of the liquefied coolant transfer
sections 110 and 102 and the evaporation section 104 and the
hydrophobic treatment is performed on the surfaces of the gaseous
coolant transfer section 106 and the condensation section 108, so
that the flow of the coolant is improved to increase the cooling
efficiency.
[0043] Further, the cross-sections of the tiny channels may be
circular, elliptical, rectangular, square, polygonal, etc.
Particularly, the magnitude of the surface tension of the coolant
can be controlled by increasing or decreasing the cross-sections of
the tiny channels in the longitudinal direction thereof (i.e., the
X axis direction), the transfer direction and velocity of the
coolant can also be controlled by forming a plurality of grooves or
nodes on the inner wall thereof.
[0044] Next, the coolant gasified in the evaporation section 104 is
transferred in the opposite direction to the liquefied coolant
transfer section 102 near the evaporation section, and the gaseous
coolant transfer section 106 is formed adjacent to the evaporation
section 104 to function as a passage through the gaseous coolant is
transferred. As shown in the drawing, the gaseous coolant transfer
section 106 may include a plurality of guides 118 so that the
gasified coolant can be transferred in a predetermined direction
(i.e., in the opposite direction to the coolant storage section
102). The guides 118 have the function of increasing the mechanical
strength of the thin plate-type cooling device 100. Accordingly,
the guides 118 may not be included if there is no problem in the
mechanical strength.
[0045] The condensation section 108 is the area where the gaseous
coolant transferred inwards through the gaseous coolant transfer
section 106 is condensed and liquefied again. In this embodiment,
the condensation section 108 is formed away from the evaporation
section 104 by a predetermined distance on the same plane.
[0046] Meanwhile, the condensation section 108 may include a
plurality of tiny channels (not shown) similar to the tiny channels
formed on the evaporation section 104. The tiny channels of the
condensation section 108 may extend to the liquefied coolant
transfer section 110 as described below, and further extend to the
liquefied coolant transfer section 102 near the evaporation
section. The tiny channels of the condensation section 108 make it
easy for the gaseous coolant to be condensed, and precipitate the
completion of the coolant circulation loop by providing surface
tension to transfer the coolant in the liquid state condensed
towards the liquefied coolant transfer section 102 near the
evaporation section.
[0047] The depth of the tiny channels of the condensation section
108 is preferably deeper than that of the tiny channels of the
evaporation section 104, which is however not limited to this. In
addition, the shape and change of the cross-sections, the formation
of the grooves or nodes of the tiny channels of the condensation
section 108 will not described in detail because they are similar
to those of the tiny channels of the evaporation section 104.
[0048] Moreover, in order to increase the efficiency of the heat
dissipation, a plurality of fins may be formed outside the
condensation section 108 of the thin plate-type cooling device 100.
The fins may have a radial shape or other shapes outside the
condensation section 108. The air brought by the fan 120 touches
the inner wall of the fins facing each other, so that the heat
dissipation efficiency can be maximized.
[0049] Further, if the fins include micro actuators, the air
surrounding the cooling device may be circulated utilizing the heat
dissipated from the condensation section 108. If the fins have a
tiny structure including thermoelectric conversion devices, the
heat dissipated from the condensation section 108 is converted into
electricity which can be used as the energy for tiny driving.
[0050] In addition, by forming the volume of the condensation
section 108 to be more than the volume of the evaporation section
104, the coolant in the gas state can be easily condensed in the
condensation section 108 only by the convention of the air
surrounding the condensation section 108.
[0051] The liquefied coolant transfer section 110 forms a passage
through which the liquefied coolant condensed in the condensation
section 108 is transferred towards the liquefied coolant transfer
section 102 near the evaporation section. As shown in the drawing,
the liquefied coolant transfer section 110 is thermally insulated
from the gaseous coolant transfer section 106, the condensation
section 108 and the evaporation section 104 by a thermal insulation
section 116.
[0052] The thermal insulation section 116 may be formed as
partitions inside the thin plate-type cooling device 100, spaces
internally sealed in the thin plate-type cooling device 100, or
openings vertically penetrating the thin plate-type cooling device
100. If the thermal insulation section 116 is the spaces internally
sealed in the thin plate-type cooling device 100, it may be in a
vacuum state or filled with an insulation substance such as
air.
[0053] As shown in the drawing, the liquefied coolant transfer
section 110 is preferably symmetry along the longitudinal direction
of the thin plate-type cooling device 100. The coolant circulation
loop being formed symmetry along the longitudinal direction of the
thin plate-type cooling device 100 is a structure which is very
advantageous in dissipating heat if it has the shape of a thin
plate, i.e. its sectional length-width ratio is large, so that the
cooling device 100 can radially dissipate the heat transferred from
the heat source utilizing the large surface area.
[0054] This bidirectional coolant circulation loop has an advantage
that even though one of the coolant circulations in the liquefied
coolant transfer section 110 is not properly performed because of
the effect of gravity depending upon the installation position of
the cooling device 100, the other coolant circulation can be
maintained.
[0055] As described above, even the liquefied coolant transfer
section 110 may include tiny channels so as not to be affected by
gravity, where a plurality of grooves (not shown) may be formed in
the tiny channels in the direction facing the coolant storage
section 102. Further, it is preferable that the sections of the
tiny channels formed on the evaporation section 104 or the
liquefied coolant transfer sections 110 and 102 gradually decrease
from the liquefied coolant transfer section 110 contacting the
condensation section 108 to the evaporation section 104 contacting
the gaseous coolant transfer section 106.
[0056] Meanwhile, a plurality of guides (not shown) may be formed
to determine the transfer direction of the liquefied coolant at a
boundary between the liquefied coolant transfer section 102 near
the evaporation section and the liquefied coolant transfer section
110 and a boundary between the condensation section 108 and the
liquefied coolant transfer section 110, whereby the resistance of
the coolant circulation occurring because the current path of the
coolant rapidly curves can be reduced.
[0057] Meanwhile, it is preferable that the evaporation section 104
is directly attached to the heat source (not shown) not via a heat
conductor to reduce the contact heat resistance, so in the
embodiment the cooling device 100 is provided with fastening means
114 for fastening the cooling device 100 to the external heat
source adjacent to the evaporation section 104 with bolts or
rivets. The fastening means 114 may not be included because it is
not relevant to the circulation of coolant.
[0058] Next, referring to FIGS. 2a to 2c, the upper plate 100b of
the thin plate-type cooling device 100 according to the first
embodiment of this invention will be described in detail. FIG. 2a
shows a schematic sectional view taken in the first direction on
the X-Y plane of the thin plate-type cooling device 100 of the
first embodiment, FIG. 2b shows a schematic sectional view taken
along the A-A' line on the Y-Z plane of the thin plate-type cooling
device 100 of the first embodiment, and FIG. 2c shows a schematic
sectional view taken along the B-B' line on the Y-Z plane of the
thin plate-type cooling device 100 of the first embodiment. In this
embodiment, the sectional view taken in the first direction shown
in FIG. 2a is the bottom view of the upper plate 100b of the thin
plate-type cooling device 100.
[0059] As shown in the drawings, in this embodiment, the upper
plate 100b of the thin plate-type cooling device 100 has a first
cavity 124 for providing a space, where the coolant in the gas
state which has not been condensed can be contained, on an area
corresponding to the gaseous coolant transfer section 106 of the
lower plate 100a. Moreover, the upper plate 100b may include the
thermal insulation section 116 corresponding to the thermal
insulation section 116 of the lower plate 100a. The upper plate
100b may be formed of the same material as that of the housing 112
of the lower plate 100a. Alternatively, the upper plate 100b may be
formed of glass, etc.
[0060] Referring to FIG. 2c, the first cavity 124 is formed in
order that its section is semi-oval in the direction parallel to
the Y axis on the Y-Z plane. By providing the space for containing
the coolant in the gas state, the first cavity 124 prevents the
coolant in the gas state which has not been condensed in the
condensation section 108 from being bubbles in the coolant in the
liquid state.
[0061] Next, referring to FIGS. 3a to 3c, the upper plate 100b of
the thin plate-type cooling device 100 according to a second
embodiment of this invention will be described in detail. FIG. 3a
shows a schematic sectional view taken in the first direction on
the X-Y plane of the thin plate-type cooling device 100 of the
second embodiment, FIG. 3b shows a schematic sectional view taken
along the A-A' line on the Y-Z plane of the thin plate-type cooling
device 100 of the second embodiment, and FIG. 3c shows a schematic
sectional view taken along the B-B' line on the Y-Z plane of the
thin plate-type cooling device 100 of the second embodiment. In
this embodiment, the sectional view taken in the first direction
shown in FIG. 3a is the bottom view of the upper plate 100b of the
thin plate-type cooling device 100.
[0062] As shown in the drawings, in this embodiment, the upper
plate 100b of the thin plate-type cooling device 100 has a
plurality of first cavities 124 on areas corresponding to the
gaseous coolant transfer section 106 of the lower plate 100a, where
the plurality of first cavities 124 respectively correspond to a
plurality of transfer paths of gaseous coolant formed by the second
guides 118 of the gaseous coolant transfer section 106 and each of
them has a semi-oval section on the Y-Z plane. As compared with the
first cavity 124 of the first embodiment, the first cavities 124 of
the second embodiment have the same functions or shapes as that of
the first embodiment, except that they are separated to correspond
to the second guides 118 of the lower plate 100a.
[0063] Next, referring to FIGS. 4a to 4c, the upper plate 100b of
the thin plate-type cooling device 100 according to a third
embodiment of this invention will be described in detail. FIG. 4a
shows a schematic sectional view taken in the first direction on
the X-Y plane of the thin plate-type cooling device 100 of the
third embodiment, FIG. 4b shows a schematic sectional view taken
along the A-A' line on the Y-Z plane of the thin plate-type cooling
device 100 of the third embodiment, and FIG. 4c shows a schematic
sectional view taken along the B-B' line on the Y-Z plane of the
thin plate-type cooling device 100 of the third embodiment. In this
embodiment, the sectional view taken in the first direction shown
in FIG. 4a is the bottom view of the upper plate 100b of the thin
plate-type cooling device 100.
[0064] As shown in the drawings, the upper plate 100b of the thin
plate-type cooling device 100 in the third embodiment further
includes a plurality of second cavities 126 formed on areas
corresponding to the condensation section 108 of the lower plate
100a. That is, the upper plate 100b includes the plurality of the
first cavities 124 formed on areas corresponding to the gaseous
coolant transfer section 106 of the lower plate 100a and the
plurality of second cavities 126 formed on areas corresponding to
the condensation section 108 of the lower plate 100a, where the
first and second cavities 124 and 126 are respectively connected to
each other.
[0065] Moreover, as shown in the drawing, it is preferable that the
width of each of the second cavities 126 becomes narrow as it
proceeds to the area corresponding to the liquefied coolant
transfer section 110. Accordingly, when the lower plate 100a and
the upper plate 100b are bound, the sections of the second cavities
126 become small as they proceed to the liquefied coolant transfer
section 110 and the surface tension to the liquefied coolant
becomes large, so the coolant in the gas state which has not been
condensed in the condensation section 108 can return to the first
cavity 124 on the area corresponding to the gaseous coolant
transfer section 106. Accordingly, since the coolant in the gas
state is contained in the coolant in the liquid state in the form
of bubbles, it is possible to prevent the coolant in the gas state
from reaching the evaporation section 104 more efficiently.
[0066] Next, referring to FIGS. 5a to 4d, the upper plate 100b of
the thin plate-type cooling device 100 according to a fourth
embodiment of this invention will be described in detail. FIG. 5a
shows a schematic sectional view taken in the first direction on
the X-Y plane of the thin plate-type cooling device 100 of the
fourth embodiment, FIG. 5b shows a schematic sectional view taken
along the A-A' line on the Y-Z plane of the thin plate-type cooling
device 100 of the fourth embodiment, FIG. 5c shows a schematic
sectional view taken along the B-B' line on the Y-Z plane of the
thin plate-type cooling device 100 of the fourth embodiment, and
FIG. 5d shows a schematic sectional view taken along the C-C' line
on the Y-Z plane of the thin plate-type cooling device 100 of the
fourth embodiment. In this embodiment, the sectional view taken in
the first direction shown in FIG. 5a is the bottom view of the
upper plate 100b of the thin plate-type cooling device 100.
[0067] As shown in the drawings, the upper plate 100b of the thin
plate-type cooling device 100 in the third embodiment further
includes a plurality of third cavities 128 formed on areas
corresponding to the liquefied coolant transfer section 110 of the
lower plate 100a. It is preferable that each of third cavities 128
has a semi-oval shape. Moreover, the plurality of third cavities
128 may be formed in a plurality of rows along the liquefied
coolant transfer section 110.
[0068] In this embodiment, when the coolant in the gas state which
has not been condensed in the condensation section 108 is
transferred to the liquefied coolant transfer section 110 in the
formed of bubbles contained in the coolant in the liquid state, it
can be captured by the plurality of third cavities 128.
Accordingly, it is possible to prevent the coolant in the gas state
from reaching the evaporation section 104 in the formed of bubbles
contained in the coolant in the liquid state far more
efficiently.
[0069] The cooling device 100 of this invention described above can
be manufactured by various methods widely known such as a MEMS
(Micro Electro Mechanical System) method or a SAM (Self Assembled
Monolayer) method using a semiconductor device manufacturing
process. Referring to FIGS. 1b and 2a, the manufacturing method
will be described briefly.
[0070] That is, the surface of the lower plate 100a of the thin
plate-type cooling device 100 is etched to form the coolant storage
section 102, the first tiny channels 120 of the evaporation section
104, the first guides 122 of the condensation section 108, the
second guides 118 of the gaseous coolant transfer section 106, and
the liquefied coolant transfer section 110.
[0071] Then, as described above, the surface of the lower plate
100b is etched to form the cavities 124, 126 and/or 128 and/or the
thermal insulation section 116.
[0072] After the lower plate 100a and the upper plate 100b where
the above structures have been formed are attached to each other,
an anodic bonding may be performed by applying a voltage to them,
so that they can be unified. Then, the pressure is reduced to make
the circulation loop be in the vacuum state through a coolant
insertion hole (not shown) formed to be connected to the coolant
storage section 102, a predetermined amount of coolant is inserted
into it, and the coolant insertion hole is sealed.
[0073] Although the present invention has been described by way of
exemplary embodiments, it should be understood that those skilled
in the art might make many changes and substitutions without
departing from the spirit and the scope of the present invention
which is defined only by the appended claims. For example, in the
configuration of the first embodiment, the cavity corresponding to
the condensation section 108 may be replaced by the cavity of the
third embodiment, or the cavity corresponding to the liquefied
coolant transfer section 110 may be replaced by the cavity of the
fourth embodiment. Moreover, alternatively, an area except the
areas the upper plate 100b on which the cavities are formed may
also have the same structure as that of the lower plate 100a.
INDUSTRIAL APPLICABILITY
[0074] According to present invention, by forming one or more
cavities having a predetermined shape on the gaseous coolant
transfer section, the condensation section and/or the liquefied
coolant transfer section in the thin plate-type cooling device, the
coolant in the gas state which has not been condensed in the
condensation section can be contained or captured, so it is
possible to prevent the dry-out phenomenon caused because the
coolant in the gas state stays in the channels to the evaporation
section and the liquefied coolant cannot be sufficiently
supplied.
[0075] In addition, according to present invention, by changing the
depth, width or shape of the channels to adjust the surface tension
of the coolant in the liquid state, the coolant in the liquid state
is rushed to the evaporation section without external power, so it
is possible to prevent the dry-out phenomenon in the evaporation
section and to sufficiently supply the coolant in the liquid state
to the evaporation section all the time.
[0076] In addition, according to present invention, surface
treatment is partly performed on the lower and upper channels, so
the flow of the coolant is improved and the cooling efficiency is
increased.
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