U.S. patent application number 16/237283 was filed with the patent office on 2019-05-09 for heat sink structure.
This patent application is currently assigned to FURUKAWA ELECTRIC CO., LTD.. The applicant listed for this patent is FURUKAWA ELECTRIC CO., LTD.. Invention is credited to Hirofumi AOKI, Yoshikatsu INAGAKI, Kenya KAWABATA, Daiki TAKEMURA.
Application Number | 20190137187 16/237283 |
Document ID | / |
Family ID | 60787282 |
Filed Date | 2019-05-09 |
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United States Patent
Application |
20190137187 |
Kind Code |
A1 |
INAGAKI; Yoshikatsu ; et
al. |
May 9, 2019 |
HEAT SINK STRUCTURE
Abstract
Provided is a heat sink structure which can reliably prevent
blocking and narrowing of an inner space of the planar heat pipe
thus having excellent heat transmission characteristics, and which
can make cooling of a plurality of heat generating elements
installed in a narrowed inner space uniform with a simple
configuration. A heat sink structure has a planar heat pipe
configured to be placed on a plurality of heat generating elements
thus being thermally coupled to the plurality of heat generating
elements; and a tubular heat pipe thermally coupled to a heat
radiating portion of the planar heat pipe at a heat receiving
portion of the tubular heat pipe.
Inventors: |
INAGAKI; Yoshikatsu; (Tokyo,
JP) ; KAWABATA; Kenya; (Tokyo, JP) ; AOKI;
Hirofumi; (Tokyo, JP) ; TAKEMURA; Daiki;
(Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FURUKAWA ELECTRIC CO., LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
FURUKAWA ELECTRIC CO., LTD.
Tokyo
JP
|
Family ID: |
60787282 |
Appl. No.: |
16/237283 |
Filed: |
December 31, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2017/024069 |
Jun 30, 2017 |
|
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16237283 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 23/3672 20130101;
H01L 23/467 20130101; F28D 2021/0029 20130101; F28F 2250/08
20130101; H01L 23/427 20130101; F28D 15/04 20130101; F28F 1/24
20130101; F28D 15/0233 20130101; F28D 15/0275 20130101; H05K
7/20336 20130101 |
International
Class: |
F28D 15/02 20060101
F28D015/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 1, 2016 |
JP |
2016-131802 |
Jul 1, 2016 |
JP |
2016-131803 |
Claims
1. A heat sink structure comprising: a planar heat pipe configured
to be placed on a plurality of heat generating elements thus being
thermally coupled to the plurality of heat generating elements; and
a tubular heat pipe thermally coupled to a heat radiating portion
of the planar heat pipe at a heat receiving portion of the tubular
heat pipe.
2. The heat sink structure according to claim 1, wherein a heat
exchange unit is provided on a heat radiating portion of the
tubular heat pipe.
3. The heat sink structure according to claim 2, wherein the heat
exchange unit includes a heat radiating fin.
4. The heat sink structure according to claim 2, wherein at least
one of the heat exchange unit and the heat radiating portion of the
tubular heat pipe is cooled by cooling air from a blower fan.
5. The heat sink structure according to any one of claims 1,
wherein a biasing member is provided on the planar heat pipe, and
the biasing member is fixed to a support member of the heat
generating element.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation application of international patent
Application No. PCT/JP2017/024069 filed Jun. 30, 2017, which claims
the benefit of Japanese Patent Application No. 2016-131802, filed
Jul. 1, 2016, and Japanese Patent Application No. 2016-131803,
filed Jul. 1, 2016, the full contents of both of which are hereby
incorporated by reference in their entirety.
BACKGROUND
Technical Field
[0002] The present disclosure relates to a heat sink structure
having excellent cooling performance with respect to a plurality of
heat generating elements installed in a narrow inner space, for
example, in an inner space having a small size in the thickness
direction. The present disclosure also relates to a heat sink
structure having excellent cooling performance with respect to heat
generating elements installed in a narrow inner space.
Background
[0003] An electronic component mounted on an electric or electronic
device, such as a semiconductor element, increases in amount of
heat generation due to high-density mounting or the like caused by
enhanced functions. Accordingly, in recent years, it is considered
important to cool the component. Further, miniaturization, thinning
or the like of the electric or electronic device causes an inner
space of a casing of the electric or electronic device to be
further narrowed. A planar heat pipe may be used as a cooling unit
for an electronic component installed in the narrowed inner
space.
[0004] As the cooling structure for an electronic component
installed in an inner space having a small size in the thickness
direction, a cooling structure is proposed which includes: a first
heat generating element provided in a casing; a heat sink provided
in the casing; a first pressing member; a plate-like first heat
pipe which has a first portion opposedly facing the first heat
generating element and a second portion displaced from the first
heat generating element, the first heat pipe being bent with the
press of the first pressing member; and a second heat pipe which
includes a tubular container coupled to the second portion of the
first heat pipe and to the heat sink (Japanese Patent Application
Laid-Open No. 2011-106793).
[0005] According to Japanese Patent Application Laid-Open No.
2011-106793, in the case where a second heat generating element is
provided in the casing, the cooling structure further includes, in
addition to the plate-like first heat pipe, a plate-like third heat
pipe which has a first portion opposedly facing the second heat
generating element, and a second portion displaced from the second
heat generating element and coupled to the second heat pipe.
[0006] However, in the technique disclosed in Japanese Patent
Application Laid-Open No. 2011-106793, the plate-like heat pipe is
bent, that is, deformed in the direction perpendicular to a planar
surface with the press of the pressing member. Accordingly, in the
plate-like heat pipe where the container has a small thickness, an
inner space, particularly, a space in the thickness direction, of
the heat pipe is blocked or narrowed and hence, a function of the
heat pipe, that is, heat transmission characteristics, is
impaired.
[0007] In the technique disclosed in Japanese Patent Application
Laid-Open No. 2011-106793, to cool the plurality of heat generating
elements, plate-like heat pipes which are formed of separate bodies
are required to be coupled to the heat generating elements
respectively, and the respective plate-like heat pipes are required
to be coupled to the second heat pipe which is a main heat pipe
having a tubular container. Accordingly, it is necessary to adjust
a size of each plate-like heat pipe according to the position of a
heat generating element. Therefore, the number of parts increases
and, at the same time, the structure is complicated.
[0008] Further, in the technique disclosed in Japanese Patent
Application Laid-Open No. 2011-106793, the plate-like heat pipes
which are formed of the separate bodies are respectively coupled to
the heat generating elements. Accordingly, when the plurality of
heat generating elements have different amounts of heat generation,
particularly, a heat generating element having a large amount of
heat generation may not be sufficiently cooled.
SUMMARY
[0009] The present disclosure is related to providing a heat sink
structure which can reliably prevent blocking and narrowing of an
inner space of the planar heat pipe thus having excellent heat
transmission characteristics, and which can make cooling of a
plurality of heat generating elements installed in a narrowed inner
space uniform with a simple configuration. The present disclosure
is also related to providing a heat sink structure which has
excellent heat transmission characteristics and functions as a
soaking plate with respect to heat generating elements installed in
a narrowed inner space with a simple configuration thus exhibiting
excellent cooling performance.
[0010] An aspect of the present disclosure is directed to a heat
sink structure which includes: a planar heat pipe configured to be
placed on a plurality of heat generating elements thus being
thermally coupled to the plurality of heat generating elements; and
a tubular heat pipe thermally coupled to a heat radiating portion
of the planar heat pipe at a heat receiving portion of the tubular
heat pipe.
[0011] In the above-mentioned aspect, placement of the planar heat
pipe on the plurality of heat generating elements allows the planar
heat pipe to be thermally coupled to the plurality of heat
generating elements and to be fixed to the heat generating
elements. In the above-mentioned aspect, portions of the planar
heat pipe to which the heat generating elements are thermally
coupled function as heat receiving portions. A portion of the
planar heat pipe to which the tubular heat pipe is thermally
coupled functions as a heat radiating portion. A portion of the
tubular heat pipe to which the planar heat pipe is thermally
coupled functions as a heat receiving portion. Further, in the
above-mentioned aspect, the plurality of heat generating elements
are thermally coupled to the planar heat pipe and hence, the
plurality of heat generating elements are thermally coupled to one
planar heat pipe, that is, to the same planar heat pipe.
[0012] Another aspect of the present disclosure is directed to the
heat sink structure where a heat exchange unit is provided on a
heat radiating portion of the tubular heat pipe.
[0013] Another aspect of the present disclosure is directed to the
heat sink structure where the heat exchange unit includes a heat
radiating fin.
[0014] Another aspect of the present disclosure is directed to the
heat sink structure where at least one of the heat exchange unit
and the heat radiating portion of the tubular heat pipe is cooled
by cooling air from a blower fan.
[0015] Another aspect of the present disclosure is directed to the
heat sink structure where a biasing member is provided on the
planar heat pipe, and the biasing member is fixed to a support
member of the heat generating element.
[0016] An aspect of the present disclosure is directed to a heat
sink structure which includes a planar heat pipe, and a tubular
heat pipe thermally coupled to the planar heat pipe, wherein a heat
generating element is thermally coupled to the position where the
planar heat pipe and the tubular heat pipe overlap with each other
as viewed in a plan view.
[0017] In the above-mentioned aspect, the heat generating element
is coupled to the planar heat pipe or to the tubular heat pipe. In
this specification, "as viewed in a plan view" means a state which
is visually recognized in the direction perpendicular to a planar
portion of the planar heat pipe.
[0018] Another aspect of the present disclosure is directed to the
heat sink structure where the tubular heat pipe is disposed on the
side of the planar heat pipe closer to the heat generating element.
In the above-mentioned aspect, the heat generating element is
coupled to the tubular heat pipe.
[0019] Another aspect of the present disclosure is directed to the
heat sink structure where the planar heat pipe is disposed on the
side of the tubular heat pipe closer to the heat generating
element. In the above-mentioned aspect, the heat generating element
is coupled to the planar heat pipe.
[0020] Another aspect of the present disclosure is directed to the
heat sink structure where a heat exchange unit is provided on a
heat radiating portion of the tubular heat pipe.
[0021] Another aspect of the present disclosure is directed to the
heat sink structure where the heat exchange unit includes a heat
radiating fin.
[0022] Another aspect of the present disclosure is directed to the
heat sink structure where at least one of the heat exchange unit
and the heat radiating portion of the tubular heat pipe is cooled
by cooling air from the blower fan.
[0023] According to the aspect of the present disclosure, placement
of the planar heat pipe on the plurality of heat generating
elements allows the planar heat pipe to be thermally coupled to the
plurality of heat generating elements. Accordingly, blocking and
narrowing of an inner space of the planar heat pipe can be reliably
prevented and, as a result, the heat sink structure can exhibit
excellent heat transmission characteristics.
[0024] According to the aspect of the present disclosure, the
plurality of heat generating elements are thermally coupled to one
planar heat pipe and hence, the number of parts of the planar heat
pipe can be reduced and, at the same time, the structure can be
simplified. According to the aspect of the present disclosure, the
plurality of heat generating elements are thermally coupled to one
planar heat pipe, and the planar heat pipe is thermally coupled to
the tubular heat pipe having excellent heat transmission
characteristics in the predetermined direction. Accordingly, even
when the plurality of heat generating elements have different
amounts of heat generation, the planar heat pipe can make heating
of the respective heat generating elements uniform thus making
cooling of the respective heat generating elements uniform.
Further, according to the aspect of the present disclosure, the
heat generating element is thermally coupled to the planar heat
pipe and hence, the heat sink structure can even reliably cool heat
generating elements installed in a narrow inner space, for example,
in an inner space having a small size in the thickness
direction.
[0025] According to the aspect of the present disclosure, the heat
exchange unit is provided on the heat radiating portion of the
tubular heat pipe and hence, heat dissipation characteristics of
the tubular heat pipe is enhanced so that the heat sink structure
can even reliably cool heat generating elements installed in a
narrow inner space.
[0026] According to the aspect of the present disclosure, the
planar heat pipe and the tubular heat pipe are thermally coupled to
each other. Accordingly, the tubular heat pipe is operated in a
state where heat from the heat generating element diffuses on a
surface of the planar heat pipe thus increasing a heat dissipation
area. Further, the heat generating element is thermally coupled to
the position where the planar heat pipe and the tubular heat pipe
overlap with each other and hence, heat is smoothly transferred
from the heat generating element to the tubular heat pipe.
Accordingly, the heat sink structure of the present disclosure has
excellent heat transmission characteristics and functions as a
soaking plate thus exhibiting excellent cooling performance with
respect to the heat generating elements.
[0027] According to the aspect of the present disclosure, in
cooling a plurality of heat generating elements which have
different amounts of heat generation, a heat generating element
having a relatively small amount of heat generation can be cooled
by the planar heat pipe having a function as a soaking plate.
Accordingly, a heat transmission amount of the tubular heat pipe
can be reduced by a corresponding amount.
[0028] According to the aspect of the present disclosure, the
planar heat pipe is used, and the number of heat generating
elements to be thermally coupled is not particularly limited.
Accordingly, the heat sink structure can exhibit excellent cooling
performance with respect to heat generating elements installed in a
narrowed inner space with a simple configuration.
[0029] According to the aspect of the present disclosure, the
tubular heat pipe is disposed on the side of the planar heat pipe
closer to the heat generating elements and hence, heat from the
heat generating elements is smoothly transferred to the tubular
heat pipe. Further, the heat from the heat generating elements
which is transferred to the planar heat pipe through the tubular
heat pipe diffuses on the surface of the planar heat pipe due to a
function of the planar heat pipe as a soaking plate thus increasing
a heat dissipation area. Accordingly, in the above-mentioned
aspect, a heat transmission amount of the tubular heat pipe can be
reduced and, therefore, the tubular heat pipe can be flattened
(thinned) and reduced in diameter. As described above, the tubular
heat pipe can be flattened and reduced in diameter and hence, the
heat sink structure can be further miniaturized.
[0030] According to the aspect of the present disclosure, the
planar heat pipe is disposed on the side of the tubular heat pipe
closer to the heat generating elements and hence, heat from the
heat generating elements first diffuses on the surface of the
planar heat pipe due to a function of the planar heat pipe as a
soaking plate and, then, is transferred to the tubular heat pipe.
Accordingly, the generation of a hot spot in the planar heat pipe
can be prevented. As described above, the generation of a hot spot
in the planar heat pipe can be prevented and hence, the heat sink
structure can exhibit excellent cooling performance with respect to
the heat generating elements.
[0031] According to the aspect of the present disclosure, the heat
exchange unit is provided on the heat radiating portion of the
tubular heat pipe and hence, heat dissipation characteristics of
the tubular heat pipe is enhanced so that the heat sink structure
can even reliably cool heat generating elements installed in a
narrow inner space.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is an explanatory view of a heat sink structure
according to a first embodiment of the present disclosure as viewed
in a side view;
[0033] FIG. 2 is an explanatory view of the heat sink structure
according to the first embodiment of the present disclosure as
viewed in a plan view;
[0034] FIG. 3 is an explanatory view of a heat sink structure
according to a second embodiment of the present disclosure as
viewed in a plan view;
[0035] FIG. 4 is an explanatory view of a heat sink structure
according to a third embodiment of the present disclosure as viewed
in a side view;
[0036] FIG. 5A is an explanatory view of a heat sink structure
according to a fourth embodiment of the present disclosure as
viewed in a side view, and FIG. 5B is an explanatory view of the
heat sink structure according to the fourth embodiment of the
present disclosure as viewed in a plan view;
[0037] FIG. 6A is an explanatory view of a heat sink structure
according to a fifth embodiment of the present disclosure as viewed
in a side view, and FIG. 6B is an explanatory view of the heat sink
structure according to the fifth embodiment of the present
disclosure as viewed in a plan view;
[0038] FIG. 7 is an explanatory view of a heat sink structure
according to a sixth embodiment of the present disclosure as viewed
in a side view;
[0039] FIG. 8 is an explanatory view of the heat sink structure
according to the sixth embodiment of the present disclosure as
viewed in a plan view;
[0040] FIG. 9A is an explanatory view of a heat sink structure
according to a seventh embodiment of the present disclosure as
viewed in a side view, and FIG. 9B is an explanatory view of the
heat sink structure according to the seventh embodiment of the
present disclosure as viewed in a plan view;
[0041] FIG. 10A is an explanatory view of a heat sink structure
according to an eighth embodiment of the present disclosure as
viewed in a side view, and FIG. 10B is an explanatory view of the
heat sink structure according to the eighth embodiment of the
present disclosure as viewed in a plan view; and
[0042] FIG. 11 is an explanatory view of a heat sink structure
according to a ninth embodiment of the present disclosure as viewed
in a plan view.
DETAILED DESCRIPTION
[0043] Hereinafter, a heat sink structure according to a first
embodiment of the present disclosure will be described with
reference to the accompanying drawings. As shown in FIGS. 1 and 2,
the heat sink structure 1 according to the first embodiment
includes a planar heat pipe 10, and a tubular heat pipe 12
thermally coupled to the planar heat pipe 10. In the heat sink
structure 1, a planar container 11 of the planar heat pipe 10 and a
tubular container 13 of the tubular heat pipe 12 come into direct
contact with each other so that the planar heat pipe 10 and the
tubular heat pipe 12 are thermally coupled to each other.
[0044] A plurality of heat generating elements (two heat generating
elements, that is, a first heat generating element 100 and a second
heat generating element 101 in FIG. 1) mounted on a substrate 102
are thermally coupled to the planar heat pipe 10. That is, the
first heat generating element 100 and the second heat generating
element 101 are thermally coupled to the same planar heat pipe 10.
Accordingly, the first heat generating element 100 and the second
heat generating element 101 are thermally coupled to each other
through the planar heat pipe 10. The planar heat pipe 10 has
portions to which the first heat generating element 100 and the
second heat generating element 101 are thermally coupled, and the
portions of the planar heat pipe 10 function as heat receiving
portions of the planar heat pipe 10.
[0045] Placement of the planar heat pipe 10 on the first heat
generating element 100 and the second heat generating element 101
allows the planar heat pipe 10 to be thermally coupled and fixed to
the first heat generating element 100 and the second heat
generating element 101.
[0046] In the heat sink structure 1, the planar heat pipe 10 may be
placed on the first heat generating element 100 and the second heat
generating element 101 so as to come into direct contact with the
first heat generating element 100 and the second heat generating
element 101. Alternatively, the planar heat pipe 10 may be placed
on the first heat generating element 100 and the second heat
generating element 101 with a thermally conductive grease not shown
in the drawing inserted between the planar heat pipe 10 and the
first heat generating element 100 and between the planar heat pipe
10 and the second heat generating element 101.
[0047] As shown in FIGS. 1 and 2, the planar heat pipe 10 has a
peripheral edge portion which is separated at a predetermined
distance from the portions of the planar heat pipe 10 to which the
first heat generating element 100 and the second heat generating
element 101 are thermally coupled. One end portion 14 of the
tubular heat pipe 12 is thermally coupled to the peripheral edge
portion of the planar heat pipe 10. In the heat sink structure 1,
one tubular heat pipe 12 is thermally coupled to the peripheral
edge portion of the planar heat pipe 10. A portion of the planar
heat pipe 10 to which the one end portion 14 of the tubular heat
pipe 12 is thermally coupled functions as a heat radiating portion
of the planar heat pipe 10.
[0048] A method for thermally coupling the planar heat pipe 10 and
the tubular heat pipe 12 to each other is not particularly limited.
For example, fixing of the tubular container 13 of the tubular heat
pipe 12 to the planar container 11 of the planar heat pipe 10 by
soldering, by swaging or the like allows the planar heat pipe 10
and the tubular heat pipe 12 to be thermally coupled to each
other.
[0049] The one end portion 14 of the tubular heat pipe 12 thermally
coupled to the planar heat pipe 10 functions as a heat receiving
portion of the tubular heat pipe 12. On the other hand, portions of
the tubular heat pipe 12 other than the one end portion 14, that
is, a center portion 15 and another end portion 16 do not come into
contact with the planar heat pipe 10. Of the center portion 15 and
the other end portion 16 of the tubular heat pipe 12, the other end
portion 16 functions as a heat radiating portion of the tubular
heat pipe 12. Unlike the planar heat pipe 10, a heat generating
element is not coupled to the tubular heat pipe 12. As shown in
FIGS. 1 and 2, the tubular heat pipe 12 may be bent, or may be used
in a straight line shape. The tubular heat pipe 12 may be partially
or wholly flattened so as to enhance thermal coupling
performance.
[0050] In the heat sink structure 1, the whole tubular heat pipe 12
including the heat receiving portion is flattened. The one end
portion 14 (heat receiving portion) of the tubular heat pipe 12
extends along the plane direction of the planar heat pipe 10. That
is, the one end portion 14 of the tubular heat pipe 12 extends
along the plane direction of the planar heat pipe 10 as viewed in a
plan view. In the similar manner as the one end portion 14, the
center portion 15 and the other end portion 16 of the tubular heat
pipe 12 also extend along the plane direction of the planar heat
pipe 10. Accordingly, the direction along which heat is transmitted
in the tubular heat pipe 12 extends in the direction substantially
parallel to the plane direction of the planar heat pipe 10.
[0051] In the heat sink structure 1, heat radiating fins 17 are
attached to the other end portion 16 of the tubular heat pipe 12
(that is, the heat radiating portion of the tubular heat pipe 12)
as a heat exchange unit. A blower fan 103 is disposed between the
heat radiating fins 17 and the planar heat pipe 10. Cooling air
from the blower fan 103 is supplied to the heat radiating fins
17.
[0052] In the heat sink structure 1, the plurality of heat
radiating fins 17 are attached to the other end portion 16 of the
tubular heat pipe 12 so that heat is smoothly discharged from the
heat radiating portion of the tubular heat pipe 12 to an external
environment. Further, the blower fan 103 is disposed between the
heat radiating fins 17 and the planar heat pipe 10. Accordingly,
with the operation of the blower fan 103, not only cooling air is
supplied to the heat radiating fins 17 but also a flow of air is
generated in the direction from the planar heat pipe 10 toward the
heat radiating fins 17, and the flow of air functions also as
cooling air for cooling the planar heat pipe 10.
[0053] The planar heat pipe 10 includes the planar container 11, a
working fluid (not shown in the drawing) sealed in an inner space
of the planar container 11, and a wick structure (not shown in the
drawing) provided in the inner space of the planar container 11.
The tubular heat pipe 12 includes the tubular container 13, a
working fluid (not shown in the drawing) sealed in an inner space
of the tubular container 13, and a wick structure (not shown in the
drawing) provided in the inner space of the tubular container
13.
[0054] A material for forming the planar container 11 and the
tubular container 13 may be copper, a copper alloy, aluminum, an
aluminum alloy, nickel, a nickel alloy, stainless steel, titanium
or the like, for example. The working fluid can be suitably
selected according to compatibility with the material for forming
the planar container 11 and the tubular container 13. The working
fluid may be water, alternative fluorocarbons, fluorocarbon group
such as Fluorinert, cyclopentane or the like, for example.
[0055] The wick structure may be a sintered body of metal powder
such as copper powder, metal mesh, wires, grooves formed on inner
surfaces of the planar container 11 and the tubular container 13 or
the like.
[0056] The heat generating elements which are cooling targets are
not particularly limited. The heat generating elements may be a
central processing unit, a graphic chip (GPU, VGA), a memory, a
capacitor, a power source and the like which are mounted on the
substrate 102 (a circuit board incorporated in an electronic
device, for example).
[0057] Next, a mechanism for a cooling effect of the heat sink
structure 1 will be described. When the heat receiving portions of
the planar heat pipe 10 receives heat from the first heat
generating element 100 and the second heat generating element 101,
the heat from the first heat generating element 100 and the second
heat generating element 101 is transmitted from the heat receiving
portions of the planar heat pipe 10 to the heat radiating portion
of the planar heat pipe 10 coupled to the one end portion 14 of the
tubular heat pipe 12. Planar portions of the planar heat pipe 10
other than the heat receiving portions of the planar heat pipe 10
function as the heat radiating portions of the planar heat pipe 10.
A portion of the heat transmitted from the heat receiving portions
to the heat radiating portion of the planar heat pipe 10 is
transferred from the heat radiating portion of the planar heat pipe
10 to the one end portion 14 of the tubular heat pipe 12, that is,
to the heat receiving portion of the tubular heat pipe 12. The heat
transferred to the heat receiving portion of the tubular heat pipe
12 is transmitted to the other end portion 16 of the tubular heat
pipe 12, that is, to the heat radiating portion of the tubular heat
pipe 12. Then, the heat is discharged from the heat radiating
portion of the tubular heat pipe 12 to an external environment
through the heat radiating fins 17.
[0058] That is, the heat from the first heat generating element 100
and the second heat generating element 101 which the planar heat
pipe 10 receives is transmitted to a portion which corresponds to
the heat radiating fins 17 through the tubular heat pipe 12 thus
being smoothly discharged to the external environment.
[0059] In the heat sink structure 1, the planar heat pipe is
thermally coupled to the first heat generating element 100 and the
second heat generating element 101 in a state of being placed on
the first heat generating element 100 and the second heat
generating element 101. Accordingly, blocking and narrowing of an
inner space of the planar heat pipe can be reliably prevented and,
therefore, the heat sink structure 1 exhibits excellent heat
transmission characteristics thus reliably cooling the plurality of
heat generating elements.
[0060] In the heat sink structure 1, the plurality of heat
generating elements (the first heat generating element 100 and the
second heat generating element 101) are thermally coupled to one
planar heat pipe 10. Accordingly, the number of parts of the planar
heat pipe 10 can be reduced and, at the same time, the heat sink
structure 1 can be simplified. Further, in the heat sink structure
1, the plurality of heat generating elements are thermally coupled
to one planar heat pipe 10, and the planar heat pipe 10 is
thermally coupled to the tubular heat pipe 12 through which heat is
transmitted to the portion where the heat radiating fins 17 are
installed. Accordingly, even when the plurality of heat generating
elements have different amounts of heat generation, the planar heat
pipe 10 can make heating of the respective heat generating elements
uniform thus making cooking of the respective heat generating
elements uniform. Further, in the heat sink structure 1, the
respective heat generating elements are thermally coupled to the
planar heat pipe and hence, the heat sink structure 1 can even
reliably cool heat generating elements installed in a narrow inner
space, for example, in an inner space having a small size in the
thickness direction.
[0061] Next, a heat sink structure according to a second embodiment
of the present disclosure will be described with reference to the
accompanying drawings. Constitutional elements identical to the
constitutional elements of the heat sink structure according to the
first embodiment of the present disclosure are given the same
reference characters, and the description is made using the same
reference characters.
[0062] In the heat sink structure 1 according to the first
embodiment, one tubular heat pipe 12 is thermally coupled to the
peripheral edge portion of the planar heat pipe 10. However, in a
heat sink structure 2 according to the second embodiment, as shown
in FIG. 3, two tubular heat pipes 12, 12' are thermally coupled to
a peripheral edge portion of the planar heat pipe 10.
[0063] In the heat sink structure 2, not only the tubular heat pipe
12 is thermally coupled to one predetermined portion of the
peripheral edge portion of the planar heat pipe 10, but also
another tubular heat pipe 12' is thermally coupled to the
peripheral edge portion of the planar heat pipe 10 at the position
on the side opposite to the tubular heat pipe 12. Heat radiating
fins 17 are also provided on a heat radiating portion of the other
tubular heat pipe 12' in the similar manner as the heat radiating
portion of the tubular heat pipe 12.
[0064] Even when the two tubular heat pipes 12 are thermally
coupled to the peripheral edge portion of the planar heat pipe 10,
in the similar manner as the heat sink structure 1, the heat sink
structure 2 can reliably cool the plurality of heat generating
elements. That is, the number of tubular heat pipes 12 thermally
coupled to the planar heat pipe 10 is not particularly limited, and
may be single or plural. The number of tubular heat pipes 12 can be
suitably selected depending on usage conditions including amount of
heat generation by a heat generating element, the number of heat
generating elements and the like.
[0065] Next, a heat sink structure according to a third embodiment
of the present disclosure will be described with reference to the
accompanying drawings. Constitutional elements identical to the
constitutional elements of the heat sink structures according to
the first and second embodiments of the present disclosure are
given the same reference characters, and the description is made
using the same reference characters.
[0066] In the heat sink structure 1 according to the first
embodiment, the planar heat pipe 10 is thermally coupled to the
respective heat generating elements (the first heat generating
element 100 and the second heat generating element 101) such that
the planar heat pipe 10 comes into direct contact with the
respective heat generating elements, or comes into contact with the
respective heat generating elements with the thermally conductive
grease interposed therebetween. However, in a heat sink structure 3
according to the third embodiment, as shown in FIG. 4, a heat
conductive member 18 is inserted between the planar heat pipe 10
and a heat generating element. In the heat sink structure 3, a
third heat generating element 104 is mounted on the substrate 102
in addition to the first heat generating element 100 and the second
heat generating element 101, that is, three heat generating
elements are mounted on the substrate 102.
[0067] The above-mentioned aspect is particularly effective when
the first heat generating element 100, the second heat generating
element 101 and the third heat generating element 104 have
different sizes in the height direction. That is, the heat
conductive member 18 is inserted between each of the heat
generating elements having a small size in the height direction
(the second heat generating element 101 and the third heat
generating element 104 in FIG. 4) and the planar heat pipe 10 thus
causing the heat generating elements to have substantially the same
height as the heat generating element having the largest size in
the height direction (the first heat generating element 100 in FIG.
4). With such a configuration, the plurality of heat generating
elements (the first heat generating element 100, the second heat
generating element 101, and the third heat generating element 104)
and the planar heat pipe 10 can be thermally coupled to each other
without causing deformation such as deflection of the planar heat
pipe 10.
[0068] The heat conductive member 18 may be formed of a thermally
conductive sheet or the like, for example. In FIG. 4, a thermally
conductive grease 19 is applied to a contact surface between the
first heat generating element 100 and the planar heat pipe 10 so as
to enhance thermal conductivity.
[0069] Next, a heat sink structure according to a fourth embodiment
of the present disclosure will be described with reference to the
accompanying drawings. Constitutional elements identical to the
constitutional elements of the heat sink structures according to
the first, second and third embodiments of the present disclosure
are given the same reference characters, and the description is
made using the same reference characters.
[0070] As shown in FIGS. 5A and 5B, in a heat sink structure 4
according to the fourth embodiment, biasing members 20 are also
provided on a surface (back surface) of the planar heat pipe 10 on
the side where heat generating elements are disposed. Providing the
biasing members 20 to the back surface of the planar heat pipe 10
allows prevention of deformation such as deflection of the planar
heat pipe 10, and also allows the planar heat pipe 10 to be biased
in the direction toward the first heat generating element 100 and
the second heat generating element 101. Accordingly, thermal
coupling performance between the planar heat pipe 10 and the first
heat generating element 100 and the second heat generating element
101 is enhanced. Further, the planar heat pipe 10 can be reliably
fixed to the substrate 102. The tubular heat pipe 12 is attached to
a surface (front surface) of the planar heat pipe 10 on the side
where the heat generating elements are not disposed.
[0071] In the heat sink structure 4, two biasing members 20 are
provided on the back surface of the planar heat pipe 10. The
respective biasing members 20 are disposed at the peripheral edge
portion of the planar heat pipe 10 so as to be oppositely
positioned with each other. The respective heat generating elements
(the first heat generating element 100 and the second heat
generating element 101) are disposed between two biasing members
20. Accordingly, the planar heat pipe 10 in a state of being biased
toward the substrate 102 side is thermally coupled to all heat
generating elements. The biasing members 20 are fixed to the
substrate 102 on which the first heat generating element 100 and
the second heat generating element 101 are mounted.
[0072] Each biasing member 20 includes a first flat portion 20-1
attached to the back surface of the planar heat pipe 10 in a
surface contact state, second flat portions 20-2 attached to the
substrate 102 in a surface contact state, and coupling portions
20-3 which connect the first flat portion 20-1 and the second flat
portions 20-2 to each other. The coupling portions 20-3 exhibit a
biasing effect.
[0073] An attaching unit configured to attach the first flat
portion 20-1 to the back surface of the planar heat pipe 10 is not
particularly limited, and soldering or the like may be adopted, for
example. A fixing unit configured to fix the second flat portions
20-2 to the substrate 102 is not particularly limited. In the heat
sink structure 4, the second flat portions 20-2 are fixed to the
substrate 102 by means of screws 21. That is, a through hole (not
shown in the drawing) which allows the insertion of the screw 21 is
formed in each second flat portion 20-2. Screw holes (not shown in
the drawing) are formed in the substrate 102. Each screw 21 is
inserted through the through hole, and is threadedly engaged with
the screw hole so that the biasing members 20 are fixed to the
substrate 102.
[0074] The biasing member 20 may be formed of a spring member such
as a leaf spring or a coil made of metal, for example.
[0075] Next, a heat sink structure according to a fifth embodiment
of the present disclosure will be described with reference to the
accompanying drawings. Constitutional elements identical to the
constitutional elements of the heat sink structures according to
the first, second, third, and fourth embodiments of the present
disclosure are given the same reference characters, and the
description is made using the same reference characters.
[0076] In the heat sink structure 4 according to the fourth
embodiment, the planar heat pipe 10 in a state of being biased
toward the substrate 102 side is thermally coupled to all heat
generating elements. However, in a heat sink structure 5 according
to the fifth embodiment, as shown in FIGS. 6A and 6B, the planar
heat pipe 10 in a state of being biased toward the substrate 102
side is thermally coupled only to some heat generating elements
(the first heat generating element 100 in FIG. 6) of a plurality of
heat generating elements (two heat generating elements consisting
of the first heat generating element 100 and the second heat
generating element 101 in FIG. 6). Through holes 22 each of which
allows the insertion of the screw 21 are formed in the planar heat
pipe 10. Through holes (not shown in the drawing) each of which
allows the insertion of the screw 21 are also formed in the biasing
members 20. Screw holes (not shown in the drawing) are formed in
the substrate 102. Each screw 21 is inserted through the through
hole 22 formed in the planar heat pipe 10 and the through hole
formed in the biasing member 20, and the screw 21 is threadedly
engaged with the screw hole formed in the substrate 102. With such
operations, the planar heat pipe 10 and the biasing members 20 are
fixed to the substrate 102.
[0077] As shown in FIG. 6B, in the heat sink structure 5, the first
heat generating element 100 is disposed between the two biasing
members 20, but the second heat generating element 101 is not
disposed between the two biasing members 20. A portion of the
planar heat pipe 10 which is not biased in the direction toward the
substrate 102 is thermally coupled to the second heat generating
element 101. The heat conductive member 18 formed of a thermally
conductive sheet or the like is inserted between the second heat
generating element 101 and the planar heat pipe 10. The planar heat
pipe 10 is biased also in the direction toward the first heat
generating element 100 due to a cushioning function of the heat
conductive member 18.
[0078] Also in the above-mentioned aspect, deformation such as
deflection of the planar heat pipe 10 can be prevented, and thermal
coupling performance between the planar heat pipe 10 and the first
heat generating element 100 can be enhanced. Further, the planar
heat pipe 10 can be reliably fixed to the substrate 102.
[0079] Next, other embodiments of the present disclosure will be
described. In the above-mentioned first to fifth embodiments, the
heat radiating fins are provided on the heat radiating portion of
the tubular heat pipe as the heat exchange unit. However, the heat
exchange unit may not be provided depending on usage conditions. In
the above-mentioned first to fifth embodiments, the blower fan is
installed in the vicinity of the heat radiating fins. However, the
blower fan may not be installed depending on usage conditions.
[0080] In the heat sink structures according to the first and
fourth embodiments, the planar heat pipe is placed on the
respective heat generating elements such that the planar heat pipe
comes into direct contact with the respective heat generating
elements, or comes into contact with the respective heat generating
elements with the thermally conductive grease interposed
therebetween. However, a heat conductive member may be disposed
between each heat generating element and the planar heat pipe.
[0081] The above-mentioned heat sink structure of the present
disclosure has excellent heat transmission characteristics, and can
make cooling of the plurality of heat generating elements installed
in a narrowed inner space uniform with a simple configuration.
Accordingly, for example, the heat sink structure of the present
disclosure has a high utility in the field of cooling a plurality
of heat generating elements installed in a space having a small
size in the thickness direction.
[0082] Hereinafter, a heat sink structure according to a sixth
embodiment of the present disclosure will be described with
reference to the accompanying drawings. As shown in FIGS. 7 and 8,
a heat sink structure 6 according to the sixth embodiment includes
the planar heat pipe 10 and the tubular heat pipe 12 thermally
coupled to the planar heat pipe 10. In the heat sink structure 6,
the planar container 11 of the planar heat pipe 10 and the tubular
container 13 of the tubular heat pipe 12 come into direct contact
with each other so that the planar heat pipe 10 and the tubular
heat pipe 12 are thermally coupled to each other.
[0083] In the heat sink structure 6, the tubular heat pipe 12 is
disposed on the side of the planar heat pipe 10 closer to heat
generating elements. The first heat generating element 100 mounted
on the substrate 102 is thermally coupled to the tubular heat pipe
12, and the second heat generating element 101 mounted on the
substrate 102 is thermally coupled to the planar heat pipe 10.
Accordingly, the first heat generating element 100 is thermally
coupled to the planar heat pipe 10 through the tubular heat pipe
12, and the second heat generating element 101 is thermally coupled
to the tubular heat pipe 12 through the planar heat pipe 10.
Accordingly, the planar heat pipe 10 has a function as a soaking
plate.
[0084] The heat sink structure 6 may be configured such that the
tubular heat pipe 12 comes into direct contact with the first heat
generating element 100 thus being thermally coupled to the first
heat generating element 100, and the planar heat pipe 10 comes into
direct contact with the second heat generating element 101 thus
being thermally coupled to the second heat generating element 101.
Alternatively, a thermally conductive grease not shown in the
drawing may be inserted between the tubular heat pipe 12 and the
first heat generating element 100 and between the planar heat pipe
10 and the second heat generating element 101 thus thermally
coupling the tubular heat pipe 12 and the first heat generating
element 100 to each other and the planar heat pipe 10 and the
second heat generating element 101 to each other.
[0085] As shown in FIGS. 7 and 8, a one end portion 14 of the
tubular heat pipe 12 is thermally coupled to the planar heat pipe
10, and the first heat generating element 100 is thermally coupled
to the one end portion 14 of the tubular heat pipe 12. That is, as
shown in FIG. 8, the first heat generating element 100 is thermally
coupled to the position where the planar heat pipe 10 and the
tubular heat pipe 12 overlap with each other as viewed in a plan
view. On the other hand, the second heat generating element 101 is
thermally coupled to the planar heat pipe 10 at the position where
the planar heat pipe 10 does not overlap with the tubular heat pipe
12 as viewed in a plan view. In the heat sink structure 6, one
tubular heat pipe 12 is thermally coupled to the planar heat pipe
10.
[0086] A method for thermally coupling the planar heat pipe 10 and
the tubular heat pipe 12 to each other is not particularly limited.
For example, fixing of the tubular container 13 of the tubular heat
pipe 12 to the planar container 11 of the planar heat pipe 10 by
soldering, by swaging or the like allows the planar heat pipe 10
and the tubular heat pipe 12 to be thermally coupled to each
other.
[0087] The one end portion 14 of the tubular heat pipe 12 thermally
coupled to the planar heat pipe 10 and to the first heat generating
element 100 functions as a heat receiving portion of the tubular
heat pipe 12. On the other hand, portions of the tubular heat pipe
12 other than the one end portion 14, that is, the center portion
15 and the other end portion 16 do not come into contact with the
planar heat pipe 10. Of the center portion 15 and the other end
portion 16 of the tubular heat pipe 12, the other end portion 16
functions as a heat radiating portion of the tubular heat pipe 12.
As shown in FIGS. 7 and 8, the tubular heat pipe 12 may be bent, or
may be used in a straight line shape. The tubular heat pipe 12 may
be partially or wholly flattened so as to enhance thermal coupling
performance.
[0088] In the heat sink structure 6, the whole tubular heat pipe 12
including the heat receiving portion is flattened. The one end
portion 14 (heat receiving portion) of the tubular heat pipe 12
extends along the plane direction of the planar heat pipe 10. That
is, the one end portion 14 of the tubular heat pipe 12 extends
along the plane direction of the planar heat pipe 10 as viewed in a
plan view. In the similar manner as the one end portion 14, the
center portion 15 and the other end portion 16 of the tubular heat
pipe 12 also extend along the plane direction of the planar heat
pipe 10. Accordingly, the direction along which heat is transmitted
in the tubular heat pipe 12 extends in the direction substantially
parallel to the plane direction of the planar heat pipe 10.
[0089] In the heat sink structure 6, the heat radiating fins 17 are
attached to the other end portion 16 of the tubular heat pipe 12
(that is, the heat radiating portion of the tubular heat pipe 12)
as a heat exchange unit. The blower fan 103 is disposed between the
heat radiating fins 17 and the planar heat pipe 10. Cooling air
from the blower fan 103 is supplied to the heat radiating fins
17.
[0090] In the heat sink structure 6, the plurality of heat
radiating fins 17 are attached to the other end portion 16 of the
tubular heat pipe 12 so that heat is smoothly discharged from the
heat radiating portion of the tubular heat pipe 12 to an external
environment. A position where the blower fan 103 is installed is
not particularly limited. However, by disposing the blower fan 103
between the heat radiating fins 17 and the planar heat pipe 10,
with the operation of the blower fan 103, not only cooling air is
supplied to the heat radiating fins 17 but also a flow of air is
generated in the direction from the planar heat pipe 10 toward the
heat radiating fins 17, and the flow of air functions also as
cooling air for cooling the planar heat pipe 10.
[0091] The planar heat pipe 10 includes the planar container 11, a
working fluid (not shown in the drawing) sealed in the inner space
of the planar container 11, and a wick structure (not shown in the
drawing) provided in the inner space of the planar container 11.
The tubular heat pipe 12 includes the tubular container 13, a
working fluid (not shown in the drawing) sealed in the inner space
of the tubular container 13, and a wick structure (not shown in the
drawing) provided in the inner space of the tubular container
13.
[0092] A material for forming the planar container 11 and the
tubular container 13 may be copper, a copper alloy, aluminum, an
aluminum alloy, nickel, a nickel alloy, stainless steel, titanium
or the like, for example. The working fluid can be suitably
selected according to compatibility with the material for forming
the planar container 11 and the tubular container 13. The working
fluid may be water, alternative fluorocarbons, fluorocarbon group
such as Fluorinert, cyclopentane or the like, for example.
[0093] The wick structure may be a sintered body of metal powder
such as copper powder, metal mesh, wires, grooves formed on inner
surfaces of the planar container 11 and the tubular container 13 or
the like.
[0094] The heat generating elements which are cooling targets are
not particularly limited. The heat generating elements may be a
central processing unit, a graphic chip (GPU, VGA), a memory, a
capacitor, a power source and the like which are mounted on the
substrate 102 (a circuit board incorporated in an electronic
device, for example).
[0095] Next, a mechanism for a cooling effect of the heat sink
structure 6 will be described. When the one end portion 14 (heat
receiving portion) of the tubular heat pipe 12 receives heat from
the first heat generating element 100, the heat transferred from
the first heat generating element 100 to the heat receiving portion
of the tubular heat pipe 12 is transmitted to the other end portion
16 of the tubular heat pipe 12, that is, to the heat radiating
portion of the tubular heat pipe 12. Then, the heat is discharged
from the heat radiating portion of the tubular heat pipe 12 to an
external environment through the heat radiating fins 17.
[0096] A portion of the heat transferred to the heat receiving
portion of the tubular heat pipe 12 is not transmitted to the heat
radiating portion of the tubular heat pipe 12, but is transferred
to the planar heat pipe 10 thermally coupled to the one end portion
14 of the tubular heat pipe 12. The heat transferred from the heat
receiving portion of the tubular heat pipe 12 to the planar heat
pipe 10 is discharged from the planar heat pipe 10 while diffusing
along a planar surface of the planar heat pipe 10. On the other
hand, when the planar heat pipe 10 receives heat from the second
heat generating element 101, in the similar manner as the heat
transferred from the first heat generating element 100, heat
transferred from the second heat generating element 101 to the
planar heat pipe 10 is discharged from the planar heat pipe 10
while diffusing along the planar surface of the planar heat pipe
10.
[0097] Further, depending on an amount of heat generation by the
second heat generating element 101, heat transferred from the
second heat generating element 101 to the planar heat pipe 10
diffuses along the planar surface of the planar heat pipe 10, and a
portion of the heat is transmitted to the one end portion 14 of the
tubular heat pipe 12, and is discharged to an external environment
from the heat radiating portion of the tubular heat pipe 12 through
the heat radiating fins 17. Accordingly, the planar heat pipe 10
has a function as a soaking plate.
[0098] That is, the heat from the first heat generating element 100
and the second heat generating element 101 which the heat sink
structure 6 receives is transmitted to a portion which corresponds
to the heat radiating fins 17 through the tubular heat pipe 12 thus
being smoothly discharged to the external environment. Further, the
heat diffuses along the planar surface of the planar heat pipe 10
thus being discharged also from the planar heat pipe 10.
[0099] As described above, in the heat sink structure 6, the planar
heat pipe 10 and the tubular heat pipe 12 are thermally coupled to
each other. Accordingly, the tubular heat pipe 12 exhibits a heat
transmission function in a state where heat from the first heat
generating element 100 and heat from the second heat generating
element 101 diffuse on the surface of the planar heat pipe 10 thus
increasing a heat dissipation area. Further, at least some heat
generating elements (first heat generating element 100) of the
plurality of heat generating elements (the first heat generating
element 100 and the second heat generating element 101) are
thermally coupled to the position where the planar heat pipe 10 and
the tubular heat pipe 12 overlap with each other. Accordingly, heat
is smoothly transferred from the first heat generating element 100
to the tubular heat pipe 12. Therefore, the heat sink structure 6
has excellent heat transmission characteristics and functions as a
soaking plate thus exhibiting excellent cooling performance with
respect to the heat generating elements.
[0100] Assume a case where the heat sink structure 6 cools a
plurality of heat generating elements (the first heat generating
element 100 and the second heat generating element 101) which have
different amounts of heat generation. In such a case, in the heat
sink structure 6, a heat generating element having a relatively
small amount of heat generation (the second heat generating element
101, for example) can be cooled by the planar heat pipe 10 having a
function as a soaking plate. Accordingly, the heat transmission
amount of the tubular heat pipe 12 can be reduced by a
corresponding amount.
[0101] In the heat sink structure 6, the planar heat pipe 10 is
used, and the number of heat generating elements to be thermally
coupled is not particularly limited. Accordingly, the heat sink
structure 6 can exhibit excellent cooling performance with respect
to heat generating elements installed in a narrowed inner space
with a simple configuration.
[0102] In the heat sink structure 6, the tubular heat pipe 12 is
disposed on the side of the planar heat pipe 10 closer to the heat
generating elements (the first heat generating element 100 and the
second heat generating element 101) (on the side closer to the
substrate 102). Accordingly, heat from the heat generating element
(the first heat generating element 100 in FIGS. 7 and 8) is
smoothly transferred to the tubular heat pipe 12. Further, heat
transferred from the respective heat generating elements (the first
heat generating element 100 and the second heat generating element
101) diffuses on the surface of the planar heat pipe 10 due to a
function of the planar heat pipe 10 as a soaking plate thus
increasing a heat dissipation area. Accordingly, a heat
transmission amount of the tubular heat pipe 12 can be reduced and,
therefore, the tubular heat pipe 12 can be flattened and reduced in
diameter. As described above, the tubular heat pipe 12 can be
flattened and reduced in diameter and hence, the heat sink
structure 6 can be further miniaturized.
[0103] Next, a heat sink structure according to a seventh
embodiment of the present disclosure will be described with
reference to the accompanying drawings. Constitutional elements
identical to the constitutional elements of the heat sink structure
according to the sixth embodiment of the present disclosure are
given the same reference characters, and the description is made
using the same reference characters.
[0104] In the heat sink structure 6 according to the sixth
embodiment, the first heat generating element 100 mounted on the
substrate 102 is coupled to the tubular heat pipe 12, and the
second heat generating element 101 mounted on the substrate 102 is
coupled to the planar heat pipe 10. However, in a heat sink
structure 7 according to the seventh embodiment, as shown in FIGS.
9A and 9B, a heat generating element is not coupled to the planar
heat pipe 10.
[0105] That is, as shown in FIG. 9, the first heat generating
element 100 is thermally coupled to the position where the planar
heat pipe 10 and the tubular heat pipe 12 overlap with each other
as viewed in a plan view. On the other hand, a heat generating
element is not coupled to the position where the tubular heat pipe
12 and the planar heat pipe 10 do not overlap with each other as
viewed in a plan view.
[0106] Also in the heat sink structure 7, the planar heat pipe 10
and the tubular heat pipe 12 are thermally coupled to each other.
Accordingly, the tubular heat pipe 12 exhibits a heat transmission
function in a state where, due to the provision of the planar heat
pipe 10, heat from the first heat generating element 100 diffuses
along the planar surface of the planar heat pipe 10 thus increasing
a heat dissipation area. Further, the heat generating element (the
first heat generating element 100) is thermally coupled to the
position where the planar heat pipe 10 and the tubular heat pipe 12
overlap with each other. Accordingly, heat is smoothly transferred
from the first heat generating element 100 to the tubular heat pipe
12. Therefore, in the similar manner as the heat sink structure 6,
the heat sink structure 7 also has excellent heat transmission
characteristics and functions as a soaking plate thus exhibiting
excellent cooling performance with respect to the heat generating
elements.
[0107] Next, a heat sink structure according to an eighth
embodiment of the present disclosure will be described with
reference to the accompanying drawings. Constitutional elements
identical to the constitutional elements of the heat sink structure
according to the sixth and seventh embodiments of the present
disclosure are given the same reference characters, and the
description is made using the same reference characters.
[0108] In the heat sink structure 6 according to the sixth
embodiment, the tubular heat pipe 12 is disposed on the side of the
planar heat pipe 10 closer to the heat generating elements.
However, in a heat sink structure 8 according to the eighth
embodiment, as shown in FIGS. 10A and 10B, the planar heat pipe 10
is disposed on the side of the tubular heat pipe 12 closer to the
heat generating elements.
[0109] Heat generating elements (a plurality of heat generating
elements, that is, the first heat generating element 100 and the
second heat generating element 101 in FIG. 10) mounted on the
substrate 102 are coupled to the planar heat pipe 10. On the other
hand, a heat generating element is not coupled to the tubular heat
pipe 12. Accordingly, both heat generating elements, that is, both
the first heat generating element 100 and the second heat
generating element 101 are thermally coupled to the tubular heat
pipe 12 through the planar heat pipe 10. Accordingly, the planar
heat pipe 10 has a function as a soaking plate.
[0110] As shown in FIG. 10B, some heat generating elements (the
first heat generating element 100 in FIG. 10B) of the plurality of
heat generating elements are thermally coupled to the planar heat
pipe 10 at the position where the planar heat pipe 10 and the
tubular heat pipe 12 overlap with each other as viewed in a plan
view. On the other hand, some of remaining heat generating elements
(the second heat generating element 101 in FIG. 10B) is thermally
coupled to the planar heat pipe 10 at the position which does not
overlap with the tubular heat pipe 12 as viewed in a plan view.
[0111] As shown in FIG. 10A, in the heat sink structure 8, the
first heat generating element 100 is thermally coupled to the
planar heat pipe 10 such that the first heat generating element 100
comes into direct contact with the planar heat pipe 10, or comes
into contact with the planar heat pipe 10 with a thermally
conductive grease (not shown in the drawing) interposed
therebetween. On the other hand, the heat conductive member 18
formed of a thermally conductive sheet or the like is inserted
between the planar heat pipe 10 and the second heat generating
element 101 so that the second heat generating element 101 is
thermally coupled to the planar heat pipe 10 through the heat
conductive member 18.
[0112] Assume a case where heat generating elements having
different sizes in the height direction are thermally coupled to
the heat sink structure 8 as described above. In such a case, the
heat conductive member 18 is inserted between the heat generating
element having a small size in the height direction (the second
heat generating element 101 in FIG. 10A) and the planar heat pipe
10. With such a configuration, an increase in thermal resistance
can be prevented, and height adjustment can be performed between
the heat generating elements having different sizes in the height
direction. Accordingly, deformation such as deflection of the
planar heat pipe 10 can be prevented and hence, the inner space of
the planar heat pipe 10 can be maintained and, as a result, the
lowering of cooling performance of the heat sink structure 8 can be
prevented.
[0113] Next, a mechanism for a cooling effect of the heat sink
structure 8 will be described. When the planar heat pipe 10
receives heat from the first heat generating element 100 and heat
from the second heat generating element 101, both the heat from the
first heat generating element 100 and the heat from the second heat
generating element 101 are discharged from the planar heat pipe 10
while diffusing on the planar heat pipe 10 along the planar surface
of the planar heat pipe 10. Further, the tubular heat pipe 12 is
provided at the position where the tubular heat pipe 12 overlaps
with the first heat generating element 100 as viewed in a plan
view, and the one end portion 14 (heat receiving portion) of the
tubular heat pipe 12 comes into direct contact with the planar heat
pipe 10. Accordingly, heat which is not discharged from the planar
heat pipe 10 is transferred to the heat receiving portion of the
tubular heat pipe 12. The heat transferred to the heat receiving
portion of the tubular heat pipe 12 is transmitted from the heat
receiving portion of the tubular heat pipe 12 to the other end
portion 16 (heat radiating portion) of the tubular heat pipe 12,
and is discharged to an external environment from the heat
radiating fins 17 provided on the heat radiating portion.
Accordingly, the tubular heat pipe 12 has a function of
transmitting the heat which is not discharged from the planar heat
pipe 10 to a portion which corresponds to the heat radiating
fins.
[0114] The planar heat pipe 10 is disposed on the side of the
tubular heat pipe 12 closer to the heat generating elements (the
first heat generating element 100 and the second heat generating
element 101) and hence, due to a function of the planar heat pipe
10 as a soaking plate, heat from the heat generating elements first
diffuses along the planar surface of the planar heat pipe 10 and,
then, is transferred to the tubular heat pipe 12. Accordingly, the
generation of a hot spot in the planar heat pipe 10 can be
prevented. As described above, in the heat sink structure 8, the
generation of a hot spot in the planar heat pipe 10 can be
prevented and hence, the heat sink structure 8 can exhibit
excellent cooling performance with respect to the heat generating
elements. Further, the planar heat pipe 10 can cover the whole heat
generating elements (the first heat generating element 100 and the
second heat generating element 101) coupled to the planar heat pipe
10 as viewed in a plan view and hence, heat transfer performance
from the heat generating element to the heat sink structure 8 is
enhanced.
[0115] Next, other embodiments of the present disclosure will be
described. In the above-mentioned sixth to eighth embodiments, one
tubular heat pipe is installed. However, the number of tubular heat
pipes to be installed is not particularly limited. A plurality of
tubular heat pipes may be installed depending on usage conditions
of the heat sink structure.
[0116] For example, in the heat sink structure 6 according to the
sixth embodiment, one tubular heat pipe 12 is thermally coupled to
the first heat generating element 100 mounted on the substrate 102.
However, as shown in FIG. 11, in a heat sink structure 9 according
to a ninth embodiment, a plurality of (two in FIG. 11) tubular heat
pipes 12, 12' may be thermally coupled to the first heat generating
element 100 mounted on the substrate 102.
[0117] In the heat sink structure 9, two tubular heat pipes 12, 12'
are thermally coupled to a position which overlaps with the first
heat generating element 100 as viewed in a plan view. In the heat
sink structure 9, portions of the two tubular heat pipes 12, 12'
which overlap with the first heat generating element 100 as viewed
in a plan view are disposed parallel to each other. Portions of the
two tubular heat pipes 12, 12' which do not overlap with the planar
heat pipe 10 as viewed in a plan view are disposed such that the
one tubular heat pipe 12 and the other tubular heat pipe 12' are
disposed substantially symmetrically with respect to a center line
of the planar heat pipe 10.
[0118] The plurality of tubular heat pipes 12, 12' are thermally
coupled to the first heat generating element 100 thus reliably
cooling the first heat generating element 100 even when the first
heat generating element 100 has a large amount of heat
generation.
[0119] The number of heat generating elements to be thermally
coupled to the position where the planar heat pipe and the tubular
heat pipe overlap with each other as viewed in a plan view is not
particularly limited. In the above-mentioned sixth to eighth
embodiments, one heat generating element is thermally coupled to
the position. However, a plurality of heat generating elements may
be thermally coupled to the position.
[0120] In the above-mentioned sixth to eighth embodiments, the heat
radiating fins are provided on the heat radiating portion of the
tubular heat pipe as the heat exchange unit. However, the heat
exchange unit may not be provided depending on usage conditions. In
the above-mentioned sixth to eighth embodiments, the blower fan is
installed in the vicinity of the heat radiating fins. However, the
blower fan may not be installed depending on usage conditions.
Further, a thermally conductive grease may be applied between the
heat generating element and the planar heat pipe or the tubular
heat pipe so as to enhance thermal coupling performance when
necessary.
[0121] The above-mentioned heat sink structure of the present
disclosure has excellent heat transmission characteristics and
functions as a soaking plate with respect to the heat generating
elements installed in a narrowed inner space with a simple
configuration thus exhibiting excellent cooling performance.
Accordingly, for example, the heat sink structure of the present
disclosure has a high utility in the field of cooling heat
generating elements mounted on a substrate.
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