U.S. patent application number 16/716655 was filed with the patent office on 2020-04-23 for sheet-shaped heat pipe.
The applicant listed for this patent is Murata Manufacturing Co., Ltd.. Invention is credited to Atsushi KISHIMOTO, Tadamasa MIURA, Takuo WAKAOKA.
Application Number | 20200124352 16/716655 |
Document ID | / |
Family ID | 56977699 |
Filed Date | 2020-04-23 |
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United States Patent
Application |
20200124352 |
Kind Code |
A1 |
WAKAOKA; Takuo ; et
al. |
April 23, 2020 |
SHEET-SHAPED HEAT PIPE
Abstract
A sheet-shaped heat pipe includes a sheet-shaped container, a
wick sealed in the container, and a working fluid sealed in the
container, wherein the sheet-shaped container includes a first
metal sheet and a second metal sheet, the first metal sheet and the
second metal sheet are superposed and at least partially bonded to
provide a closed internal space therebetween, and a thickness of
the sheet-shaped container is about 0.5 mm or less.
Inventors: |
WAKAOKA; Takuo;
(Nagaokakyo-shi, JP) ; KISHIMOTO; Atsushi;
(Nagaokakyo-shi, JP) ; MIURA; Tadamasa;
(Nagaokakyo-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Murata Manufacturing Co., Ltd. |
Nagaokakyo-shi |
|
JP |
|
|
Family ID: |
56977699 |
Appl. No.: |
16/716655 |
Filed: |
December 17, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15712175 |
Sep 22, 2017 |
10544994 |
|
|
16716655 |
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PCT/JP2015/080027 |
Oct 23, 2015 |
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15712175 |
|
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62234757 |
Sep 30, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28D 2020/0013 20130101;
F28D 15/04 20130101; F28D 2021/0028 20130101; H01L 23/427 20130101;
F28F 2255/06 20130101; F28F 21/081 20130101; F28D 15/02 20130101;
F28D 15/046 20130101; F28D 15/0233 20130101 |
International
Class: |
F28D 15/02 20060101
F28D015/02; F28F 21/08 20060101 F28F021/08; F28D 15/04 20060101
F28D015/04; H01L 23/427 20060101 H01L023/427 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 26, 2015 |
JP |
2015-064666 |
Claims
1. A thin heat dissipating plate comprising: a metal plate; and a
sheet-shaped heat pipe disposed on the metal plate; wherein the
metal plate includes a recess; the sheet-shaped heat pipe includes:
a sheet-shaped container; a wick sealed in the container; and a
working fluid sealed in the container; the sheet-shaped container
includes a first metal sheet and a second metal sheet; the first
metal sheet and the second metal sheet have different thicknesses
from each other; the first metal sheet and the second metal sheet
are superposed and at least partially bonded to provide a closed
internal space therebetween; and the sheet-shaped heat pipe is
disposed in the recess.
2. The thin heat dissipating plate according to claim 1, wherein a
thickness of the first metal sheet is larger than a thickness of
the second metal sheet.
3. The thin heat dissipating plate according to claim 1, wherein a
thickness of the second metal sheet is larger than a thickness of
the first metal sheet.
4. The thin heat dissipating plate according to claim 1, wherein
the metal sheet and the sheet-shaped heat pipe are bonded.
5. The thin heat dissipating plate according to claim 1, wherein
the metal sheet and the sheet-shaped heat pipe are bonded with at
least one of solder, a conductive adhesive, and a thermal
conductive tape.
6. The thin heat dissipating plate according to claim 1, wherein
the metal sheet and the sheet-shaped heat pipe are mechanically
fixed.
7. The thin heat dissipating plate according to claim 1, wherein
the metal sheet and the sheet-shaped heat pipe are mechanically
fixed by at least one of screw holes and claws.
8. The thin heat dissipating plate according to claim 1, wherein a
thickness of the sheet-shaped container is about 0.5 mm or
less.
9. The thin heat dissipating plate according to claim 1, wherein at
least one of the first metal sheet and the second metal sheet
includes a thick portion.
10. The thin heat dissipating plate according to claim 1, wherein
each of the first metal sheet and the second metal sheet includes a
thick portion.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority to Japanese
Patent Application No. 2015-064666 filed on Mar. 26, 2015 and U.S.
Provisional Application No. 62/234,757 filed on Sep. 30, 2015, and
is a Continuation Application of PCT Application No.
PCT/JP2015/080027 filed on Oct. 23, 2015. The entire contents of
each application are hereby incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to a sheet-shaped heat pipe
and a thin heat dissipating plate using the sheet-shaped heat
pipe.
2. Description of the Related Art
[0003] In recent years, the amount of heat generation has been
increased along with high integration and high performance of
elements. Also, since the heating density has been increased by
miniaturization of products, it has been important to take measures
to dissipate heat. This circumstance is more pronounced in mobile
terminals, such as smartphones and tablets, and thermal design is
significantly difficult. Recently, for example, a graphite sheet
has often been used as a heat countermeasure member, but the heat
transport amount thereof is insufficient.
[0004] On the other hand, a heat pipe (or a vapor chamber) is an
example of a heat countermeasure member having a high heat
transport ability. The total apparent thermal conductivity of the
heat pipe is about several times to several tens of times higher
than that of metal, such as copper or aluminum.
[0005] For example, as a heat countermeasure member using a heat
pipe, Japanese Unexamined Patent Application Publication No.
2011-003604 proposes a heat dissipating plate incorporating a heat
pipe. In this heat dissipating plate, a groove is provided in a
plate of a body portion of a heat dissipating unit or a heat
conducting member to be provide on the body portion from above, and
a heat pipe is set in the groove. The plate, the heat pipe, and the
heat conducting member are bonded with a bonding material such as
solder.
[0006] Japanese Unexamined Patent Application Publication No.
2015-095629 proposes a high-heat-dissipating thin cooling structure
using a heat pipe for a mobile electronic device. In this cooling
structure, a heat pipe that is flattened by being compressed in the
thickness direction is set on a heat dissipating plate, and one end
of the heat pipe is disposed at a position to receive heat from a
heating component. The heating component is covered with a shield
plate. The plate has a stepped portion that is bent toward a
substrate to be thinner than the heating component at a position
outside the heating component in the width direction or the length
direction. One end of the flat heat pipe is held between the
stepped portion and the heat dissipating plate.
[0007] In the heat dissipating plate described in Japanese
Unexamined Patent Application Publication No. 2011-003604, the
plate of the body portion needs to ensure a sufficient thickness to
form the recess in which the heat conducting member is fitted and
the groove in which the heat pipe is fitted. In information
terminals, such as smartphones and tablets, which are required to
be thin, it is difficult for the heat dissipating plate of Japanese
Unexamined Patent Application Publication No. 2011-003604 to
achieve the required thinning.
[0008] On the other hand, the heat dissipating plate including the
flat heat pipe described in Japanese Unexamined Patent Application
Publication No. 2015-095629 also has a thickness limitation because
it is necessary to form the groove holding the heat pipe in the
shield case. Further, while the heat countermeasure member of
Japanese Unexamined Patent Application Publication No. 2015-095629
is required to have a function as an electromagnetic shield for
noise removal and a function of increasing the mechanical strength
of a housing, the functions may become insufficient if the portions
are thinned to decrease the thickness of the heat countermeasure
member. Further, since the flat heat pipe described in Japanese
Unexamined Patent Application Publication No. 2015-095629 is
flattened by forming a round pipe and then compressing the round
pipe, it is difficult to easily change the wall thickness of the
pipe.
SUMMARY OF THE INVENTION
[0009] Preferred embodiments of the present invention provide thin
heat countermeasure members, for example, a heat pipe or a heat
dissipating plate.
[0010] The present inventors discovered, as a result of intensive
studies made to solve the above-described problems, that the above
problems could be solved by using a sheet-shaped heat pipe in which
a wick and a working fluid are sealed in a sheet-shaped container
formed by bonding metal sheets.
[0011] According to a first preferred embodiment of the present
invention, a sheet-shaped heat pipe includes a sheet-shaped
container, a wick sealed in the container, and a working fluid
sealed in the container, wherein the sheet-shaped container
includes a first metal sheet and a second metal sheet, the first
metal sheet and the second metal sheet are superposed and partially
bonded to define a closed internal space, and a thickness of the
sheet-shaped container is preferably about 0.5 mm or less, for
example.
[0012] According to a second preferred embodiment of the present
invention, a thin heat dissipating plate includes a metal plate,
and the above-described sheet-shaped heat pipe disposed on the
metal plate such that the metal plate and a principal surface of
the second metal sheet are in close contact with each other.
[0013] According to a third preferred embodiment of the present
invention, a thin heat dissipating plate includes a metal plate,
and a sheet-shaped heat pipe disposed on the metal plate, wherein
the sheet-shaped heat pipe includes a sheet-shaped container, a
wick sealed in the container, and a working fluid sealed in the
container, the sheet-shaped container includes a first metal sheet
and a second metal sheet, the first metal sheet and the second
metal sheet are superposed and partially bonded to define a closed
internal space, and the second metal sheet is combined with the
metal plate or the metal plate also defines and functions as the
second metal sheet.
[0014] According to a fourth preferred embodiment of the present
invention, an electronic device includes a sheet-shaped heat pipe
or a thin heat dissipating plate according to a preferred
embodiment of the present invention.
[0015] According to various preferred embodiments of the present
invention, it is possible to provide heat countermeasure members to
be used in a small electronic device by using sheet-shaped heat
pipes according to a preferred embodiment of the present invention
in which the wick and the working fluid are sealed in the
sheet-shaped container including bonded metal sheets. The
sheet-shaped heat pipes of preferred embodiments of the present
invention and the cooling plates including the sheet-shaped heat
pipes of preferred embodiments of the present invention are able to
have a high degree of design flexibility, for example, the
thickness of a container wall, and are able to have various
functions in addition to a cooling function.
[0016] The above and other elements, features, steps,
characteristics and advantages of the present invention will become
more apparent from the following detailed description of the
preferred embodiments with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a schematic sectional view of a sheet-shaped heat
pipe 1a according to a preferred embodiment of the present
invention.
[0018] FIG. 2 is a schematic sectional view of a sheet-shaped heat
pipe 1b according to another preferred embodiment of the present
invention.
[0019] FIG. 3 is a schematic sectional view of a sheet-shaped heat
pipe 1c according to another preferred embodiment of the present
invention.
[0020] FIG. 4 is a schematic sectional view of a sheet-shaped heat
pipe 1d according to another preferred embodiment of the present
invention.
[0021] FIG. 5 is a schematic sectional view of a sheet-shaped heat
pipe 1e according to another preferred embodiment of the present
invention.
[0022] FIG. 6 is a schematic sectional view of a sheet-shaped heat
pipe 1f according to another preferred embodiment of the present
invention.
[0023] FIG. 7 is a schematic sectional view of a thin heat
dissipating plate 11a according to a preferred embodiment of the
present invention.
[0024] FIG. 8 is a schematic sectional view of a thin heat
dissipating plate 11b according to another preferred embodiment of
the present invention.
[0025] FIG. 9 is a schematic sectional view of a thin heat
dissipating plate 11c according to another preferred embodiment of
the present invention.
[0026] FIG. 10 is a schematic sectional view of a thin heat
dissipating plate 11d according to another preferred embodiment of
the present invention.
[0027] FIG. 11 is a schematic sectional view of a thin heat
dissipating plate 11e according to another preferred embodiment of
the present invention.
[0028] FIG. 12 is a schematic sectional view of a thin heat
dissipating plate 11f according to another preferred embodiment of
the present invention.
[0029] FIG. 13 is a schematic sectional view of a thin heat
dissipating plate 11g according to another preferred embodiment of
the present invention.
[0030] FIG. 14 is a schematic sectional view of a thin heat
dissipating plate 11k according to another preferred embodiment of
the present invention.
[0031] FIG. 15 is a schematic sectional view of a thin heat
dissipating plate 11m according to another preferred embodiment of
the present invention.
[0032] FIG. 16 schematically illustrates a setting example of the
heat dissipating plate of a preferred embodiment of the present
invention in an electronic component.
[0033] FIG. 17 schematically illustrates another setting example of
the heat dissipating plate of a preferred embodiment of the present
invention in an electronic component.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] Sheet-shaped heat pipes according to preferred embodiments
of the present invention will be described below.
[0035] In this description, "heat pipe" refers to a device that
includes a container and a working fluid and a wick sealed in the
container and is able to transport heat from an evaporation unit to
a cooling unit. Heat is transported in a cycle in which the working
fluid evaporates by absorbing heat in the evaporation unit, the
working fluid in a gas phase moves to the cooling unit and
condenses by dissipating the heat in the cooling unit, and the
working fluid in a liquid phase moves to the evaporation unit
again.
[0036] In the container, a first metal sheet and a second metal
sheet are superposed and bonded together at a portion, for example,
at a peripheral edge portion to define a closed internal space. The
first metal sheet and the second metal sheet do not always need to
be completely aligned, and it is only required that the first metal
sheet and the second metal sheet be superposed to such an extent to
ensure a sufficient space to seal the wick and the working fluid
therein.
[0037] While the materials of the first metal sheet and the second
metal sheet are not particularly limited, they are, for example,
preferably copper, aluminum, titanium, nickel, silver, or an alloy
of these materials.
[0038] In a preferred embodiment of the present invention, the
material of the first metal sheet and the material of the second
metal sheet are preferably different. By making the materials of
the sheets different, one function is able to be obtained by one of
the metal sheets, and another function is able to be obtained by
the other metal sheet.
[0039] While the above-described functions are not particularly
limited, examples of the functions include a strength increasing
function, a rigidity increasing function, a heat conducting
function, and an electromagnetic shield function.
[0040] In a preferred embodiment of the present invention, a
thermal conductivity of the material of one of the metal sheets may
preferably be higher than a thermal conductivity of the material of
the other metal sheet. By making the thermal conductivity of one of
the metal sheets high, heat is able to be efficiently transmitted,
and another function is able to be obtained by the other metal
sheet.
[0041] Examples of the material having a high thermal conductivity
include copper, silver, or an alloy of these materials.
[0042] In another preferred embodiment of the present invention, a
hardness of the material of one of the metal sheets may preferably
be higher than a hardness of the material of the other metal sheet.
By making the hardness of one of the metal sheets high, the
strength and rigidity is able to be secured by this metal sheet,
and another function is able to be obtained by the other metal
sheet.
[0043] Examples of the material having a high hardness include
titanium and an aluminum alloy.
[0044] Thicknesses of the first metal sheet and the second metal
sheet may preferably be within a range of about 0.018 mm to about
0.38 mm, and more preferably within a range of about 0.018 mm to
about 0.18 mm, for example. The thicknesses of the first metal
sheet and the second metal sheet may be either equal or
different.
[0045] In a preferred embodiment of the present invention, the
thicknesses of the first metal sheet and the second metal sheet are
preferably different from each other. By making the thicknesses of
the sheets different, one function is able to be obtained by one of
the metal sheets and another function is able to be obtained by the
other metal sheet. For example, a thicker metal sheet is able to
have a higher electromagnetic shield function, a higher strength
increasing function, and a higher rigidity increasing function. In
contrast, a thinner metal sheet is able to have a function of more
efficiently transmitting heat in the thickness direction.
[0046] In a preferred embodiment of the present invention, the
first metal sheet and the second metal sheet may each preferably
have a thick portion and a thin portion. That is, one metal sheet
may include a thicker portion (thick portion) and a thinner portion
(thin portion). By changing the thickness in one metal sheet, the
one metal sheet is able to provide a plurality of functions.
[0047] In this preferred embodiment, the first metal sheet and the
second metal sheet may each have a thick portion and a thin
portion, or only one of the sheets may have a thick portion and a
thin portion and the other sheet may have a constant thickness.
[0048] A sheet-shaped heat pipe according to a preferred embodiment
of the present invention may have various functions in various
combinations by combining the thicknesses and materials of the
first metal sheet and the second metal sheet.
[0049] The working fluid sealed in the container of the
sheet-shaped heat pipe according to a preferred embodiment of the
present invention is not particularly limited as long as it is able
to cause a gas-liquid phase change in an environment inside the
container, and, for example, water, alcohol, or alternative
chlorofluorocarbon may preferably be used. In a preferred
embodiment of the present invention, the working fluid is an
aqueous compound, and preferably, water.
[0050] The wick sealed in the container of a sheet-shaped heat pipe
according to various preferred embodiments of the present invention
is not particularly limited, and for example, may preferably have a
structure to move the working fluid by capillary pressure. In this
description, such a structure to move the working fluid by
capillary pressure is referred to as a capillary structure, and
includes a fine structure including irregularities, such as pores,
grooves, or projections, for example, a porous structure, a fiber
structure, a groove structure, or a mesh structure.
[0051] While the position of the wick is not particularly limited,
the wick preferably continuously extends from an evaporation unit
to a condensation unit inside the container. For example, when the
container is shaped as a hollow rectangular or substantially
rectangular parallelepiped, the wick may be provided on one inner
wall surface or may be provided on all inner wall surfaces. The
wick may be molded integrally with the container or may be obtained
by working the inner wall surface of the container, or a separately
provided wick may be attached to the inner wall surface of the
container.
[0052] The capillary structure of the wick is not particularly
limited, and may be a known structure used in conventional heat
pipes and vapor chambers.
[0053] The wick may be an assembly of grooves, irregularities, or
projections disposed at a predetermined interval on the inner wall
surface of the container, or may be a sintered metal, a sintered
ceramic material, or a fiber.
[0054] In a preferred embodiment of the present invention, the
sheet-shaped heat pipe preferably includes a porous body disposed
on the wick.
[0055] In a preferred embodiment of the present invention, the
porous body may have an average pore diameter of about 100 nm or
less, for example. The average pore diameter of the porous body is
preferably within a range of about 0.3 nm to about 100 nm, more
preferably within a range of about 0.3 nm to about 50 nm, and
further preferably within a range of about 0.3 nm to about 20 nm,
for example. As the average pore diameter decreases, the amount of
working fluid retained by the porous body increases and the
capillary pressure increases.
[0056] The average pore diameter of the porous body may be measured
by a gas adsorption method. Specifically, gas is physically
adsorbed on surfaces of pores and the pore distribution is measured
from the relationship between the adsorption amount and the
relative pressure. As the above-described gas, nitrogen is
preferably used when the pore diameter is more than or equal to
about 0.7 nm and argon is preferably used when the pore diameter is
less than about 0.7 nm, for example.
[0057] In a preferred embodiment of the present invention, the
porous body may have a specific surface area of about 100 m.sup.2/g
or more. The specific surface area of the porous body may be
preferably within a range of about 100 m.sup.2/g to about 20,000
m.sup.2/g, more preferably within a range of about 500 m.sup.2/g to
about 15,000 m.sup.2/g, and further preferably within a range of
about 1,000 m.sup.2/g to about 10,000 m.sup.2/g, for example. As
the specific surface area increases, the amount of working fluid
that is able to be retained by the porous body increases.
[0058] The specific surface area of the porous body may be measured
by the gas adsorption method. Specifically, gas is physically
adsorbed on the surfaces of the pores, and the specific surface
area can be converted from the relationship between the adsorption
amount and the relative pressure, for example, according to a
calculation formula of the BET method. As the gas, nitrogen is used
when the pore diameter is more than or equal to about 0.7 nm and
argon is used when the pore diameter is less than about 0.7 nm, for
example.
[0059] In a preferred embodiment of the present invention, the
porous body may have a working-fluid retaining ratio of about 5% or
more by volume, preferably about 10% or more by volume, and more
preferably about 20% or more by volume, for example. As the
working-fluid retaining ratio increases, the amount of working
fluid that is able to be retained by the porous body increases. By
increasing the retaining ratio, the sheet-shaped heat pipe is able
to achieve a larger heat transport amount.
[0060] The working-fluid retaining ratio refers to the ratio (% by
volume) of the working fluid to be adsorbed on the porous body to
the volume of the porous body. The weight change rate (reduction
rate) is measured by thermogravimetry when the porous body is
heated from about 40.degree. C. to about 160.degree. C., for
example, and the retaining ratio is calculated from the weight
change rate and the density of the porous body.
[0061] While the porous body is not particularly limited, it may
preferably be, for example, zeolite or a porous metallic complex.
Other examples of the porous body include mesoporous silica, a
carbon-based material such as activated carbon, and diatomite.
[0062] Zeolite is not particularly limited as long as it has the
pore diameter, specific surface area, or working-fluid retaining
ratio described above, and may be appropriately selected according
to desired performance. Typical examples of zeolites usable in
preferred embodiments of the present invention include FAU type,
LTA type, AFI type, MFI type, MOR type, AEL type, CHA type, BEA
type, and LTL type zeolites according to the IZA Standard.
[0063] A porous metallic complex refers to a porous substance
composed of metallic ions, organic ligands, and other components.
The porous metallic complex is well known to those skilled in the
art, and is also referred to as porous coordination polymers (PCP)
or metal organic frameworks (MOF).
[0064] The porous metallic complex used in the present invention is
not particularly limited as long as it has the pore diameter,
specific surface area, or working-fluid retaining ratio described
above, and may be appropriately selected according to desired
performance. Typical examples of porous metallic complexes usable
in preferred embodiments of the present invention include an
MIL-based complex, a ZIF-based complex, an MOF-based complex,
HKUST-1, and JAST-1.
[0065] The porous body is preferably hydrophilic. By using a
hydrophilic porous body, when a hydrophilic working fluid, for
example, water is used, the capillary pressure increases, and this
increases the heat transport amount.
[0066] According to the type of the porous body, the desorption
temperature of the working fluid differs. Therefore, the working
temperature of the sheet-shaped heat pipe according to preferred
embodiments of the present invention is able to be controlled by
adjusting the type and amount of porous body disposed on the
wick.
[0067] Since the porous body also absorbs and releases energy when
absorbing and desorbing water, heat is more efficiently transported
by utilizing this absorption and desorption energy.
[0068] In a preferred embodiment of the present invention, the
sheet-shaped heat pipe is operated only by latent heat of the
working fluid to transport heat at a low temperature, and is able
to more efficiently transport heat by utilizing the absorption and
desorption energy of the porous body in addition to the latent heat
of the working fluid at a high temperature.
[0069] The method of disposing the porous body on the wick is not
particularly limited. For example, a porous body film is formed by
coating, or fine powder of the porous body is bound onto the wick.
For example, when zeolite is used, it may be disposed on a wick by
immersing the wick in a slurry containing zeolite and a
low-melting-point glass and pulling up and heating the wick. When a
porous metallic complex is used, it may be formed on a wick by
immersing the wick in a solution containing metal ions and organic
ligands serving as raw materials of the porous metallic complex and
heating and drying the wick.
[0070] The thickness of the sheet-shaped heat pipe according to
preferred embodiments of the present invention may be about 0.5 mm
or less, and preferably within a range of about 0.05 mm to about
0.50 mm, for example. By setting the thickness of the sheet-shaped
heat pipe to about 0.5 mm or less, the heat countermeasure member
is able to be made thinner. By setting the thickness of the
sheet-shaped heat pipe to about 0.05 mm or more, the strength of
the sheet-shaped heat pipe is able to be more easily ensured. From
the viewpoint of ensuring both thinning and strength, the thickness
of the sheet-shaped heat pipe is more preferably within a range of
about 0.15 mm to about 0.30 mm, for example.
[0071] Members other than the wick and the working fluid may be
contained inside the container of the sheet-shaped heat pipe
according to preferred embodiments of the present invention. For
example, the container may include a support member that maintains
a space in the container so that the space is not crushed, or a
member that assists in movements of a working fluid in a gas phase
and a working fluid in a liquid phase, such as an inner wall that
separates moving spaces of the working fluids.
[0072] In a preferred embodiment of the present invention, the
sheet-shaped heat pipe may preferably include a resin portion on
the first metal sheet and/or the second metal sheet.
[0073] In a preferred embodiment of the present invention, the
resin portion is preferably provided on only one of the first metal
sheet and the second metal sheet.
[0074] In another preferred embodiment of the present invention,
the resin portion is preferably provided on the first metal sheet
and the second metal sheet.
[0075] The resin portion may be located at any positions on the
first metal sheet and the second metal sheet, and may entirely
cover the first metal sheet and the second metal sheet or may
partially cover the first metal sheet and the second metal sheet.
The resin portions on the first metal sheet and the second metal
sheet may be located either at opposed positions or at unopposed
positions.
[0076] While a resin material that is used for the resin portion is
not particularly limited, examples of the resin include silicone
resin, epoxy resin, an ethylene-vinyl acetate copolymer (EVA),
chlorinated polyethylene (CPE), urethane resin, and polyimide
resin.
[0077] In a preferred embodiment of the present invention, the
resin portion may preferably include other materials. When the
resin portion includes other materials, various functions are able
to be provided to the sheet-shaped heat pipes of preferred
embodiments of the present invention.
[0078] Examples of other materials include an electromagnetic-wave
absorbing material (for example, a magnetic filler) and a heat
storage material (for example, a paraffin filler or vanadium
oxide). By using the electromagnetic-wave absorbing material, the
sheet-shaped heat pipe obtains a function of shielding
electromagnetic-wave noise. By using the heat storage material, the
rise in temperature of the heating element is delayed.
[0079] In a preferred embodiment of the present invention, a
thermal conductivity of the resin portion is preferably lower than
a thermal conductivity of the first metal sheet or the second metal
sheet including the resin portion. By making the thermal
conductivity of the resin portion lower than the thermal
conductivity of the metal sheet, the soaking effect in the planar
direction of the metal sheet including the resin portion is
improved.
[0080] In a preferred embodiment of the present invention, an
elastic modulus of the resin portion is preferably lower than an
elastic modulus of the first metal sheet or the second metal sheet
including the resin portion. By making the elastic modulus of the
resin portion lower than the elastic modulus of the metal sheet,
the stress applied to the sheet-shaped heat pipe is relaxed, and
breakage is prevented.
[0081] A thickness of the resin portion may preferably be about 0.5
mm or less, more preferably within a range of about 0.05 mm to
about 0.50 mm, and further preferably within a range of about 0.15
mm to about 0.30 mm, for example.
[0082] The resin portion may be set by applying resin on a surface
of the metal sheet, or a separately produced resin sheet may be
attached. Alternatively, a metal sheet on which a resin portion is
provided beforehand may be used
[0083] A production method for the sheet-shaped heat pipes
according to preferred embodiments of the present invention is not
particularly limited as long as the method is able to obtain the
above-described structures. For example, the sheet-shaped heat pipe
may be obtained by superposing and bonding two metal sheets to
provide an opening through which a wick and a working fluid are
sealed, disposing the wick and the working fluid into the container
through the opening, and then sealing the opening. Alternatively,
the sheet-shaped heat pipe may be obtained by disposing a wick on
one metal sheet, superposing the other metal sheet thereon,
partially bonding the metal sheets, disposing a working fluid
through an opening, and sealing the opening. The wick may be formed
on the metal sheets beforehand. While the bonding method for the
first metal sheet and the second metal sheet is not particularly
limited, for example, resistance welding, laser welding, ultrasonic
bonding, and bonding using a brazing material including solder may
preferably be used.
[0084] As described above, the sheet-shaped heat pipes according to
preferred embodiments of the present invention can have various
functions according to combinations of the thickness, material, and
resin part of the first metal sheet and the second metal sheet that
constitute the container. For example, according to preferred
embodiments of the sheet-shaped heat pipe, the following
sheet-shaped heat pipes are provided.
First Preferred Embodiment
[0085] A sheet-shaped heat pipe 1a according to a first preferred
embodiment of the present invention as shown in FIG. 1 includes a
first metal sheet 2 and a second metal sheet 3 having the same or
substantially the same thickness. The sheet-shaped heat pipe 1a of
the first preferred embodiment is not distinguished between an
upper side and a lower side, and is easily set in, for example, an
electronic component.
Second Preferred Embodiment
[0086] In a sheet-shaped heat pipe 1b according to a second
preferred embodiment of the present invention, the thickness of one
metal sheet (a first metal sheet 2 in FIG. 2) is larger than the
thickness of the other metal sheet (a second metal sheet 3 in FIG.
2). In the sheet-shaped heat pipe 1b of the second preferred
embodiment, for example, the thicker metal sheet provides a higher
strength, a higher rigidity, a higher noise removing function, and
a higher electromagnetic shield function.
Third Preferred Embodiment
[0087] In a sheet-shaped heat pipe 1c according to a third
preferred embodiment of the present invention, one metal sheet (a
first metal sheet 2 in FIG. 3) has a thick portion 4 and a thin
portion 5 and the other metal sheet (a second metal sheet 3 in FIG.
3) has a constant thickness. In the sheet-shaped heat pipe 1c of
the third preferred embodiment, for example, a higher
electromagnetic shield function is obtained by the thick portion of
the metal sheet and heat is more efficiently exchanged between the
inside of the container and the outside of the container by the
thin portion.
Fourth Preferred Embodiment
[0088] In a sheet-shaped heat pipe 1d according to a fourth
preferred embodiment of the present invention as shown in FIG. 4, a
first metal sheet 2 and a second metal sheet 3 include respective
thick portions 4 and thin portions 5, and the thick portion and the
thin portion of one of the metal sheets are respectively opposed to
the thin portion and the thick portion of the other metal sheet. In
the sheet-shaped heat pipe 1d of the fourth preferred embodiment,
for example, a higher electromagnetic shield function is obtained
by the thick portions of the metal sheets, and heat is more
efficiently exchanged between the inside of the container and the
outside of the container by the thin portions. Moreover, these
functions are provided to both surfaces of the heat pipe.
Fifth Preferred Embodiment
[0089] In a sheet-shaped heat pipe 1e according to a fifth
preferred embodiment of the present invention, one metal sheet (a
first metal sheet 2 in FIG. 5) includes a resin portion 6. The
sheet-shaped heat pipe 1e of the fifth preferred embodiment is able
to have various functions due to the resin portion being provided
on the metal sheet.
Sixth Preferred Embodiment
[0090] In a sheet-shaped heat pipe 1f according to a sixth
preferred embodiment of the present invention as shown in FIG. 6, a
first metal sheet 2 and a second metal sheet 3 include respective
resin portions 6 and the resin portions 6 are not opposed to each
other. The sheet-shaped heat pipe 1f of the sixth preferred
embodiment is able to have various functions because it includes a
plurality of resin portions.
[0091] In FIGS. 1 to 6, for simplicity, a wick and a working fluid
are not illustrated.
[0092] Next, thin heat dissipating plates according to preferred
embodiments of the present invention will be described.
[0093] A thin heat dissipating plate according to a preferred
embodiment of the present invention includes a metal plate and the
above-described sheet-shaped heat pipe disposed on the metal plate
such that the metal plate and a principal surface of the second
metal sheet are in close contact with each other.
[0094] The material of the metal plate is not particularly limited
as long as it is metal, and may be, for example, copper, an Al
alloy, a Mg alloy, and titanium.
[0095] The thickness of the metal plate may be about 1.0 mm or
less, and preferably within a range of about 0.10 mm to about 1.0
mm, for example. By setting the thickness of the thin heat
dissipating plate at about 1.0 mm or less, the heat countermeasure
member is able to be thinned. By setting the thickness of the thin
heat dissipating plate at about 0.10 mm or more, the strength of
the thin heat dissipating plate is able to be ensured more easily.
From the viewpoint of achieving both a smaller thickness and a
higher strength, the thickness of the thin heat dissipating plate
is more preferably within a range of about 0.30 mm to about 0.80
mm, for example.
[0096] In a preferred embodiment of the present invention, the
metal plate may preferably include a recess in which the
sheet-shaped heat pipe is disposed. The depth of the recess is
appropriately set according to the thickness of the sheet-shaped
heat pipe to be set therein, and may be, for example, about 0.5 mm
or less, preferably within a range of about 0.05 mm to about 0.50
mm, and more preferably within a range of about 0.15 mm to about
0.30 mm.
[0097] In the thin heat dissipating plate according to preferred
embodiments of the present invention, the above-described
sheet-shaped heat pipe is disposed on the metal plate such that the
metal plate and a principal surface of the second metal sheet are
in close contact with each other.
[0098] In a preferred embodiment of the present invention, the
metal plate preferably has a recess and the sheet-shaped heat pipe
is provided in the recess. By setting the sheet-shaped heat pipe in
the recess, the thickness is prevented from being significantly
increased by the sheet-shaped heat pipe. Preferably, the depth of
the recess is less than or equal to the thickness of the
sheet-shaped heat pipe, for example, less than the thickness of the
sheet-shaped heat pipe or equal to the thickness of the
sheet-shaped heat pipe.
[0099] A method for setting the metal plate and the sheet-shaped
heat pipe is not particularly limited. A sheet-shaped heat pipe
produced beforehand may be provided on the metal plate, or a
sheet-shaped heat pipe may be produced and provided directly on the
metal plate.
[0100] When the sheet-shaped heat pipe produced beforehand is
provided, for example, it is preferably bonded with solder, a
conductive adhesive, or a thermal conductive tape or is
mechanically fixed by using screw holes or claws.
[0101] When the sheet-shaped heat pipe is directly produced on the
metal plate, for example, it can be produced by the following
non-limiting exemplary method. First, a second metal sheet is
disposed or formed on a metal plate, a wick is then disposed or
formed, a first metal sheet is provided thereon, the first metal
sheet and the second metal sheet are bonded except for a sealing
port of a working fluid, and the sealing port is closed and sealed
after the working fluid is sealed therein. By directly producing
the sheet-shaped heat pipe on the metal plate, the metal plate and
the second metal sheet are combined, and the sheet-shaped heat pipe
and the metal plate are easily brought into closer contact with
each other. As a result, the efficiency in exchanging heat between
the sheet-shaped heat pipe and the heat dissipating plate is
improved, and the space in the recess of the heat dissipating plate
is effectively utilized. Thus, the capacity of the container is
further increased.
[0102] In a preferred embodiment of the present invention, a
container may preferably be defined by a metal plate and a first
metal sheet by directly disposing a wick on the metal plate without
disposing a second metal sheet thereon, and then bonding the metal
plate and the first metal sheet. That is, in this preferred
embodiment, the metal plate also functions as the second metal
sheet. In this preferred embodiment, the capacity of the container
is further increased.
[0103] A thin heat dissipating plate according to a preferred
embodiment of the present invention includes a metal plate, and a
sheet-shaped heat pipe disposed on the metal plate, wherein the
sheet-shaped heat pipe includes a sheet-shaped container, a wick
sealed in the container, and a working fluid sealed in the
container, the sheet-shaped container includes a first metal sheet
and a second metal sheet, the first metal sheet and the second
metal sheet are superposed and partially bonded to provide a closed
internal space, and the second metal sheet is combined with the
metal plate or the metal plate also functions as the second metal
sheet.
[0104] The heat dissipating plates according to preferred
embodiments of the present invention may have various functions by
appropriating selecting the specific structure of the
above-described sheet-shaped heat pipe. For example, the following
heat dissipating plates are described as preferred embodiments of
the heat dissipating plates of the present invention.
Seventh Preferred Embodiment
[0105] A heat dissipating plate 11a according to a seventh
preferred embodiment of the present invention as shown in FIG. 7
includes a sheet-shaped heat pipe 16 produced beforehand is
disposed in a recess of a metal plate 17. For example, the heat
dissipating plate of the seventh preferred embodiment has a high
degree of design flexibility in design and production method of the
sheet-shaped heat pipe because the sheet-shaped heat pipe is
separately produced.
Eighth Preferred Embodiment
[0106] A heat dissipating plate 11b according to an eighth
preferred embodiment of the present invention as shown in FIG. 8
includes a metal plate 17 and a second metal sheet 13 that are
combined with each other. Since the second metal sheet 13 of the
sheet-shaped heat pipe is in extremely close contact with the metal
plate, for example, the heat dissipating plate of the eighth
preferred embodiment has a high efficiency in exchanging heat
between the sheet-shaped heat pipe and the metal plate, and is able
to increase the capacity of the container.
Ninth Preferred Embodiment
[0107] A heat dissipating plate 11c according to a ninth preferred
embodiment of the present invention as shown in FIG. 9 includes a
first metal sheet 12 that is thick and a second metal sheet 13 that
is thin. For example, the heat dissipating plate of the ninth
preferred embodiment has higher strength and rigidity, especially,
higher rigidity, and obtains a higher noise removing function and a
higher electromagnetic shield function because the thick metal
sheet is located on the surface of the heat dissipating plate.
Further, since the second metal sheet that separates the metal
plate and the inside of the container is thin, for example, the
heat dissipating plate efficiently is able to exchange heat between
the metal plate and the inside of the container.
Tenth Preferred Embodiment
[0108] A heat dissipating plate 11d according to a tenth preferred
embodiment of the present invention as shown in FIG. 10 includes a
second metal sheet 13 that is thick and a first metal sheet 12 that
is thin. For example, the heat dissipating plate of the tenth
preferred embodiment efficiently receives heat from the outside,
especially, from a heating unit because the first metal sheet 12
arranged as an exposed surface of the sheet-shaped heat pipe is
thin. Also, the heat dissipating plate also ensures strength
because the second metal sheet 13 is thick.
Eleventh Preferred Embodiment
[0109] A heat dissipating plate 11e according to a eleventh
preferred embodiment of the present invention as shown in FIG. 11
includes a first metal sheet 12 that includes a thick portion 14
and a thin portion 15 and a second metal sheet 13 that has a
constant thickness. For example, the heat dissipating plate of the
eleventh preferred embodiment obtains a higher electromagnetic
shield function by the thick portion of the first metal sheet 12
and efficiently receives heat from the outside, especially, from a
heating unit by the thin portion.
Twelfth Preferred Embodiment
[0110] A heat dissipating plate 11f according to a twelfth
preferred embodiment of the present invention as shown in FIG. 12
includes a first metal sheet 12 and a second metal sheet 13 that
include respective thick portions 14 and thin portions 15 and the
thick portion and the thin portion of one of the metal sheets are
respectively opposed to the thin portion and the thick portion of
the other metal sheet. For example, the heat dissipating plate of
the twelfth preferred embodiment obtains a higher electromagnetic
shield function by the thick portions of the metal sheets,
efficiently receives heat from a heating unit by the thin portions,
and more efficiently exchanges heat between the inside of the
container and the metal plate.
Thirteenth Preferred Embodiment
[0111] In a heat dissipating plate 11g according to a thirteenth
preferred embodiment of the present invention as shown in FIG. 13,
the material of a first metal sheet 12 and the material of a second
metal sheet 13 are different from each other. For example, the heat
dissipating plate of the thirteenth preferred embodiment is able to
provide various functions, such as a strength increasing function,
a rigidity increasing function, a heat conducting function, and an
electromagnetic shield function, because the material of the first
metal sheet 12 and the material of the second metal sheet 13 are
different from each other.
Fourteenth Preferred Embodiment
[0112] In a heat dissipating plate 11h according to an fourteenth
preferred embodiment of the present invention, the thermal
conductivity of a first metal sheet 12 is higher than the thermal
conductivity of a second metal sheet 13. For example, the heat
dissipating plate of the fourteenth preferred embodiment
efficiently receives heat from the outside, especially, from a
heating unit, and therefore, increases the heat receiving
efficiency without changing the thickness because the thermal
conductivity of the first metal sheet 12 is high.
Fifteenth Preferred Embodiment
[0113] In a heat dissipating plate 11i according to a fifteenth
preferred embodiment of the present invention, the hardness of a
first metal sheet 12 is higher than the hardness of a second metal
sheet 13. For example, the heat dissipating plate of the fifteenth
preferred embodiment increases the rigidity without increasing the
thickness because the hardness of the first metal sheet 12 is
high.
Sixteenth Preferred Embodiment
[0114] In a heat dissipating plate 11j according to a sixteenth
preferred embodiment of the present invention, the hardness of a
second metal sheet 13 is higher than the hardness of a first metal
sheet 12. For example, the heat dissipating plate of the sixteenth
preferred embodiment increases the strength without increasing the
thickness because the hardness of the second metal sheet 13 is
high.
Seventeenth Preferred Embodiment
[0115] In a heat dissipating plate 11k according to an seventeenth
preferred embodiment of the present invention as shown in FIG. 14,
a resin portion is provided on a first metal sheet 12. The heat
dissipating plate of the seventeenth preferred embodiment is able
to provide various functions due to the resin portion.
Eighteenth Preferred Embodiment
[0116] In a heat dissipating plate 11m according to a eighteenth
preferred embodiment of the present invention as shown in FIG. 15,
a resin portion is provided on a first metal sheet 12 and a resin
portion is provided on a second metal sheet 13, and these resin
portions are not opposed to each other. The heat dissipating plate
of the eighteenth preferred embodiment is able to have various
functions due to the resin portions.
Nineteenth Preferred Embodiment
[0117] In a heat dissipating plate 11n according to a nineteenth
preferred embodiment of the present invention, each resin portion
in the seventeenth and eighteenth preferred embodiments preferably
includes an electromagnetic-wave absorbing material and/or a heat
storage material. The heat dissipating plate of the nineteenth
preferred embodiment has an electromagnetic-wave absorbing function
or a heat storage function due to the electromagnetic-wave
absorbing material or the heat storage material contained in the
resin portion.
Twentieth Preferred Embodiment
[0118] A heat dissipating plate 11p according to a twentieth
preferred embodiment of the present invention, the thermal
conductivity of each resin portion in the seventeenth and
eighteenth preferred embodiments is preferably lower than the
thermal conductivity of the first metal sheet 12 and the second
metal sheet 13.
Twenty-First Preferred Embodiment
[0119] A heat dissipating plate 11q according to a twenty-first
preferred embodiment of the present invention, the elastic modulus
of each resin portion in the seventeenth and eighteenth preferred
embodiments is preferably lower than the elastic modulus of the
first metal sheet 12 and the second metal sheet 13.
[0120] In FIGS. 7 to 15, for simplicity, a wick and a working fluid
are not illustrated.
[0121] Since the sheet-shaped heat pipes and the thin heat
dissipating plates according to preferred embodiments of the
present invention are thin, they are suitably used in electronic
devices that are required to have a small size, especially, a small
thickness, for example, mobile terminals such as smartphones and
tablets.
[0122] Therefore, preferred embodiments of the present invention
also provide electronic devices including a sheet-shaped heat pipes
or a thin heat dissipating plates according to preferred
embodiments of the invention.
[0123] When a heat dissipating plate according to a preferred
embodiment of the present invention is provided in an electronic
device, it is normally arranged such that a portion of the
sheet-shaped heat pipe is in direct or indirect contact with a
heating element or under the influence of heat from the heating
element.
[0124] FIGS. 16 and 17 illustrate examples of assemblies in an
electronic device.
[0125] Referring to FIG. 16, a heat dissipating plate 21 according
to a preferred embodiment of the present invention is arranged such
that a sheet-shaped heat pipe 22 is thermally coupled to a heating
component 32 inside an electronic device 31 through a thermal
interface material 33 and a metal plate 23 transfers heat to a
liquid crystal display 34. In this case, heat generated in the
heating component 32 is transmitted to the sheet-shaped heat pipe
22 through the thermal interface material 33, and is transferred
over a wide range of the metal plate 23 by the sheet-shaped heat
pipe 22. The heat transferred to the metal plate is further
dissipated to the outside through the liquid crystal display
34.
[0126] Referring to FIG. 17, a heat dissipating plate 21 according
to a preferred embodiment of the present invention is arranged such
that a sheet-shaped heat pipe 22 is thermally coupled to a heating
component 32 inside an electronic device 31 through a thermal
interface material 33 and a metal plate 23 is disposed in contact
with a housing 35. In this case, heat generated in the heating
component 32 is transmitted to the sheet-shaped heat pipe 22
through the thermal interface material 33, and is transferred over
a wide range of the metal plate 23 by the sheet-shaped heat pipe
22. The heat transferred to the metal plate is further dissipated
to the outside through the housing 35.
[0127] The sheet-shaped heat pipes and the thin heat dissipating
plates according to preferred embodiments of the present invention
are also able to function as a shield while being electrically
coupled to a ground of a circuit in an electric device.
[0128] Since the sheet-shaped heat pipes and the thin heat
dissipating plates according to preferred embodiments of the
present invention are thin, they are able to be used for a wide
range of applications. In particular, the sheet-shaped heat pipes
and the thin heat dissipating plates may preferably be used, for
example, as a cooling device for a small electronic device, for
applications requiring a small size and efficient heat
transport.
[0129] While preferred embodiments of the present invention have
been described above, it is to be understood that variations and
modifications will be apparent to those skilled in the art without
departing from the scope and spirit of the present invention. The
scope of the present invention, therefore, is to be determined
solely by the following claims.
* * * * *