U.S. patent application number 12/817210 was filed with the patent office on 2011-07-21 for flat heat pipe.
This patent application is currently assigned to FURUI PRECISE COMPONENT (KUNSHAN) CO., LTD.. Invention is credited to SHENG-LIANG DAI, JIN-PENG LIU, YUE LIU, YU-LIANG LO, SHENG-LIN WU, SHENG-GUO ZHOU.
Application Number | 20110174466 12/817210 |
Document ID | / |
Family ID | 43227209 |
Filed Date | 2011-07-21 |
United States Patent
Application |
20110174466 |
Kind Code |
A1 |
LIU; YUE ; et al. |
July 21, 2011 |
FLAT HEAT PIPE
Abstract
An exemplary flat heat pipe with an evaporator section and a
condenser section includes a casing, and a first wick structure and
a second wick structure in the casing. The casing defines a first
vapor channel within the evaporator section. The first wick
structure contacts an inner surface of the casing at the condenser
section. The first wick structure includes a contact portion in
contact with the inner surface of the casing, and an isolated
portion from the inner surface of the casing. The isolated portion
and the inner surface of the casing cooperatively define
therebetween a second vapor channel in communication with the first
vapor channel. The second wick structure contacts the inner surface
of the casing at the evaporator section. The second wick structure
joins the first wick structure at a joint between the evaporator
section and the condenser section.
Inventors: |
LIU; YUE; (KunShan City,
CN) ; DAI; SHENG-LIANG; (KunShan City, CN) ;
LIU; JIN-PENG; (KunShan City, CN) ; ZHOU;
SHENG-GUO; (KunShan City, CN) ; WU; SHENG-LIN;
(Tu-Cheng, TW) ; LO; YU-LIANG; (Tu-Cheng,
TW) |
Assignee: |
FURUI PRECISE COMPONENT (KUNSHAN)
CO., LTD.
KunShan City
CN
FOXCONN TECHNOLOGY CO., LTD.
Tu-Cheng
TW
|
Family ID: |
43227209 |
Appl. No.: |
12/817210 |
Filed: |
June 17, 2010 |
Current U.S.
Class: |
165/104.26 |
Current CPC
Class: |
H01L 2924/0002 20130101;
H01L 2924/00 20130101; H01L 2924/0002 20130101; H01L 23/427
20130101 |
Class at
Publication: |
165/104.26 |
International
Class: |
F28D 15/04 20060101
F28D015/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 15, 2010 |
CN |
201010300332.3 |
Claims
1. A flat heat pipe with an evaporator section and a condenser
section at opposite ends thereof, the flat heat pipe comprising: a
hollow flat casing defining a first vapor channel within the
evaporator section; a first wick structure received in the casing
at the condenser section, the first wick structure in contact with
an inner surface of the casing at the condenser section, the first
wick structure comprising at least one contact portion in contact
with the inner surface of the casing, and at least one isolated
portion isolated from the inner surface of the casing, the at least
one isolated portion and the inner surface of the casing
cooperatively defining a second vapor channel therebetween, the
first and second vapor channels in communication with each other;
and a second wick structure received in the casing at the
evaporator section, the second wick structure in contact with an
inner surface of the casing at the evaporator section, the second
wick structure joining the first wick structure at a joint between
the evaporator section and the condenser section.
2. The flat heat pipe of claim 1, wherein the first wick structure
is formed by weaving a plurality of metal wires, the second wick
structure is made of sintered metal powder, and the first and
second wick structures are joined together by sintering.
3. The flat heat pipe of claim 2, wherein the first wick structure
is a hollow tube, and comprises a top wall, a bottom wall opposite
to the top wall, and a first sidewall and a second sidewall
interconnecting the top and bottom walls, the first wick structure
is located in the center of the casing, and the second vapor
channel comprises two passages respectively defined between the
sidewalls of the first wick structure and the inner surface of the
casing.
4. The flat heat pipe of claim 3, wherein the at least one contact
portion comprises two contact portions, the at least one isolated
portion comprises two isolated portions, the top and bottom walls
of the first wick structure form the two contact portions in
contact with the inner surface of the casing, respectively, and the
first and second sidewalls of the first wick structure form the two
isolated portions isolated from the inner surface of the
casing.
5. The flat heat pipe of claim 2, further comprising another first
wick structure received in the casing at the condenser section,
wherein the casing comprises opposite top and bottom plates, and
two opposite side plates between the top and bottom plates, the two
first wick structures are disposed at opposite inner sides of the
casing at the side plates, respectively, each of the two first wick
structures comprises a top wall, a bottom wall opposite to the top
wall, and a first sidewall and a second sidewall interconnecting
the top and bottom walls, the first sidewalls of the first wick
structures faces each other, and the second vapor channel is
defined between the first sidewalls of the first wick structures
and the inner surface of the casing.
6. The flat heat pipe of claim 5, wherein the at least one contact
portion comprises two contact portions, the at least one isolated
portion comprises two isolated portions, the top wall, the bottom
wall and the first sidewall of each first wick structure
cooperatively form one of the contact portions in contact with the
inner surface of the casing, and the second sidewall of each first
wick structure forms one of the isolated portions isolated from the
inner surface of the casing.
7. The flat heat pipe of claim 2, further comprising another two
first wick structures, wherein the casing comprises opposite top
and bottom plates, and two opposite side plates between the top and
bottom plates, the three first wick structures are spaced from each
other, two of the first wick structures are disposed at opposite
inner sides of the casing at the side plates, respectively, and the
other first wick structure is located in the center of the casing,
each of the first wick structures comprises a top wall, a bottom
wall opposite to the top wall, and a first sidewall and a second
sidewall interconnecting the top and bottom walls, the second vapor
channel comprises two passages, one of the passages is defined
between the second sidewall of the first wick structure at one of
the side plates of the casing, the first sidewall of the first wick
structure in the center of the casing and the inner surface of the
casing, and the other passage is defined between the second
sidewall of the first wick structure at the other side plate of the
casing, the second sidewall of the first wick structure in the
center of the casing and the inner surface of the casing.
8. The flat heat pipe of claim 7, wherein the at least one contact
portion comprises four contact portions, the at least one isolated
portion comprises four isolated portions, the top wall, the bottom
wall and the first sidewall of each of the first wick structures at
the opposite side plates of the casing cooperatively form two of
the contact portions in contact with the inner surface of the
casing, the top and bottom walls of the first wick structure in the
center of the casing form another two of the contact portions in
contact with the inner surface of the casing, respectively, the
second sidewall of each of the first wick structures at the
opposite side plates of the casing form two of the isolated
portions isolated from the inner surface of the casing, and the
first and second sidewalls of the first wick structure in the
center of the casing form another two of the isolated portions
isolated from the inner surface of the casing, respectively.
9. The flat heat pipe of claim 1, wherein the second wick structure
contacts a portion of the inner surface of the casing at the
evaporator section which corresponds to an area of an outside of
the casing designated for contacting a heat-generating electronic
component.
10. The flat heat pipe of claim 1, wherein the first wick structure
is an extruded flattened shape.
11. The flat heat pipe of claim 1, wherein a height of the casing
is less than 2 millimeters.
12. The flat heat pipe of claim 1, wherein the first wick structure
is a hollow tube, and defines an inner space therein, and the inner
space communicates with the first vapor channel.
13. The flat heat pipe of claim 12, wherein the second wick
structure blocks a portion of an end of the inner space of the
first wick structures at the joint.
14. A flat heat pipe with an evaporator section and a condenser
section at opposite ends thereof, the flat heat pipe comprising: a
hollow flat casing defining a first vapor channel within the
evaporator section; a first wick structure received in the casing
at the condenser section, the first wick structure formed by
weaving a plurality of metal wires, the first wick structure
comprising at least one isolated portion isolated from an inner
surface of the casing, the at least one isolated portion and the
inner surface of the casing cooperatively defining a second vapor
channel therebetween, the first and second vapor channels in
communication with each other; and a second wick structure received
in the casing at the evaporator section, the second wick structure
made of sintered metal powder, the second wick structure joining
the first wick structure at a joint between the evaporator section
and the condenser section.
15. The flat heat pipe of claim 14, wherein the first and second
wick structures are joined together by sintering.
16. The flat heat pipe of claim 14, wherein the first wick
structure is a hollow tube, and comprises a top wall, a bottom wall
opposite to the top wall, and a first sidewall and a second
sidewall interconnecting the top and bottom walls, the first wick
structure is located in the center of the casing, and the second
vapor channel comprises two passages defined between the sidewalls
of the first wick structure and the inner surface of the casing,
respectively.
17. The flat heat pipe of claim 14, further comprising another
first wick structure, wherein the casing comprises opposite top and
bottom plates, and two opposite side plates between the top and
bottom plates, the two first wick structures are disposed at the
opposite side plates of the casing, respectively, each of the two
first wick structures comprises a top wall, a bottom wall opposite
to the top wall, and a first sidewall and a second sidewall
interconnecting the top and bottom walls, the first sidewalls of
the first wick structures face each other, and the second vapor
channel is defined between the first sidewalls of the first wick
structures and the inner surface of the casing.
18. The flat heat pipe of claim 14, further comprising another two
first wick structures, wherein the casing comprises opposite top
and bottom plates, and two opposite side plates between the top and
bottom plates, the three first wick structures are spaced from each
other, two of the first wick structures are disposed at opposite
side plates of the casing, respectively, the other first wick
structure is located in the center of the casing, each of the first
wick structures comprises a top wall, a bottom wall opposite to the
top wall, and a first sidewall and a second sidewall
interconnecting the top and bottom walls, the second vapor channel
comprises two passages, one of the passages is defined between the
second sidewall of the first wick structure at one of the side
plates of the casing, the first sidewall of the first wick
structure in the center of the casing and the inner surface of the
casing, and the other passage is defined between the second
sidewall of the first wick structure at the other side plate of the
casing, the second sidewall of the first wick structure in the
center of the casing and the inner surface of the casing.
19. The flat heat pipe of claim 14, wherein the second wick
structure contacts a portion of the inner surface of the casing at
the evaporator section which corresponds to an area of an outside
of the casing designated for contacting a heat-generating
electronic component.
20. The flat heat pipe of claim 14, wherein the first wick
structure is a hollow tube, and defines an inner space therein, the
second wick structure blocks a portion of an end of the inner space
of the first wick structure at the joint, and the inner space of
the first wick structure communicates with the first vapor channel.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is related to two co-pending applications
respectively entitled "FLAT HEAT PIPE AND METHOD FOR MANUFACTURING
THE SAME" (attorney docket number US31525) and "FLAT HEAT PIPE WITH
VAPOR CHANNEL" (attorney docket number US32037), assigned to the
same assignee of this application and filed on the same date as
this application. The two related applications are incorporated
herein by reference.
BACKGROUND
[0002] 1. Technical Field
[0003] The disclosure generally relates to heat transfer
apparatuses, and particularly to a heat pipe with high heat
transfer efficiency.
[0004] 2. Description of Related Art
[0005] Heat pipes are widely used in various fields for heat
dissipation purposes due to their excellent heat transfer
performance. One commonly used heat pipe includes a sealed tube
made of heat conductive material, with a working fluid contained
therein. The working fluid conveys heat from one end of the tube,
typically referred to as an evaporator section, to the other end of
the tube, typically referred to as a condenser section. Preferably,
a wick structure is provided inside the heat pipe, lining an inner
wall of the tube, and drawing the working fluid back to the
evaporator section after it condenses at the condenser section.
[0006] During operation, the evaporator section of the heat pipe
maintains thermal contact with a heat-generating electronic
component. The working fluid at the evaporator section absorbs heat
generated by the electronic component, and thereby turns to vapor.
Due to the difference in vapor pressure between the two sections of
the heat pipe, the generated vapor moves, carrying the heat with
it, toward the condenser section. At the condenser section, the
vapor condenses after transferring the heat to, for example, fins
thermally contacting the condenser section. The fins then release
the heat into the ambient environment. Due to the difference in
capillary pressure which develops in the wick structure between the
two sections, the condensate is then drawn back by the wick
structure to the evaporator section where it is again available for
evaporation.
[0007] In ordinary use, the heat pipe is flattened to increase a
contact area with the electronic component and enable smaller
electronic products to incorporate the heat pipe. However, this may
downsize a vapor channel of the heat pipe through which the vapor
flows from the evaporator section to the condenser section. In such
case, the generated vapor may not move toward the condenser section
in a timely manner, and the heat transfer efficiency of the heat
pipe is thereby reduced.
[0008] What is needed, therefore, is a flat heat pipe which can
overcome the described limitations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Many aspects of the present embodiments can be better
understood with reference to the following drawings. The components
in the drawings are not necessarily drawn to scale, the emphasis
instead placed upon clearly illustrating the principles of the
present embodiments. Moreover, in the drawings, like reference
numerals designate corresponding parts throughout the various
views, and all the views are schematic.
[0010] FIG. 1 is an abbreviated, lateral side plan view of a heat
pipe in accordance with a first embodiment of the disclosure.
[0011] FIG. 2 is an enlarged, transverse cross section of the heat
pipe of FIG. 1, taken along line II-II thereof.
[0012] FIG. 3 is an enlarged, transverse cross section of the heat
pipe of FIG. 1, taken along line thereof.
[0013] FIG. 4 is an enlarged, longitudinal cross section of the
heat pipe of FIG. 1, taken along line IV-IV thereof.
[0014] FIG. 5 is similar to FIG. 3, but shows a transverse cross
section of a heat pipe according to a second embodiment of the
disclosure.
[0015] FIG. 6 is similar to FIG. 3, but shows a transverse cross
section of a heat pipe according to a third embodiment of the
disclosure.
[0016] FIG. 7 is similar to FIG. 2, but shows a transverse cross
section of a heat pipe according to a fourth embodiment of the
disclosure.
DETAILED DESCRIPTION
[0017] Referring to FIGS. 1-3, a heat pipe 10 in accordance with a
first embodiment of the disclosure is shown. The heat pipe 10 is a
flat heat pipe, and includes a flat tube-like casing 11 with two
ends thereof sealed, and a variety of elements enclosed in the
casing 11. Such elements include two first wick structures 12, 13,
a second wick structure 14, and a working medium (not shown).
[0018] The casing 11 is made of metal or metal alloy with a high
heat conductivity coefficient, such as copper, copper-alloy, or
other suitable material. The casing 11 is elongated, and has an
evaporator section 111 and an opposite condenser section 113
located end-to-end along a longitudinal direction thereof. The
casing 11 has a width larger than its height. In particular, the
casing 11 has a flattened transverse cross section. To meet the
height requirements of common electronic products, the height of
the casing 11 is preferably less than 2 millimeters (mm). The
casing 11 is hollow, and includes a top plate 114, a bottom plate
115 opposite to the top plate 114, and two side plates 116, 117
interconnecting the top and bottom plates 114, 115. The top and
bottom plates 114, 115 are flat and parallel to each other. The
side plates 116, 117 are arcuate and respectively disposed at
opposite lateral sides of the casing 11. The casing 11 defines a
first vapor channel 141 within the evaporator section 111.
[0019] The second wick structure 14 is made of sintered metal
powder, such as copper powder or other suitable material. The
second wick structure 14 is only located in the evaporator section
111, and sandwiched between the top and bottom plates 114, 115 of
the casing 11. In this embodiment, the second wick structure 14 is
annular, and snugly contacts an entire inner surface of the casing
11 at the evaporator section 111. The first vapor channel 141 is
defined in the second wick structure 14.
[0020] Each of the first wick structures 12, 13 is an elongated
hollow tube, and extends longitudinally from a joint 149 located
between the evaporator section 111 and the condenser section 113
into and through an entire length of the condenser section 113. An
inner space 140 is longitudinally defined in each of the first wick
structures 12, 13. Each of the first wick structures 12, 13 is a
monolayer-type structure formed by weaving a plurality of metal
wires such as copper or stainless steel wires. The first wick
structures 12, 13 thus have a plurality of pores therein.
Alternatively, each of the first wick structures 12, 13 can be a
multilayer-type structure layered along a radial direction thereof
by weaving a plurality of metal wires.
[0021] The first wick structures 12, 13 are only located in the
condenser section 113. In this embodiment, the first wick
structures 12, 13 are disposed at opposite inner sides of the
casing 11, respectively. Each of the first wick structures 12, 13
is extruded to a flattened shape by the inner surface of the casing
11. Each first wick structure 12, 13 has a flattened transverse
cross section, similar in principle to the flattened transverse
cross section of the casing 11. In particular, each first wick
structure 12, 13 includes a top wall 121, 131, a bottom wall 122,
132 opposite to the top wall 121, 131, and a left sidewall 123, 133
and a right sidewall 124, 134 interconnecting the top and bottom
walls 121, 131, 122, 132. The top and bottom walls 121, 131, 122,
132 are flat and parallel to each other. The left and right
sidewalls 123, 133, 124, 134 are arcuate and respectively disposed
at opposite lateral sides of each first wick structure 12, 13.
[0022] The first wick structure 12 is disposed at a right inner
side of the casing 11 within the condenser section 113. The top
wall 121, the bottom wall 122 and the right sidewall 124 of the
first wick structure 12 cooperatively form a U-shaped contact
portion in contact with an inner surface of the casing 11. In
particular, the contacting inner surface of the casing 11 includes
the side plate 116, and a portion of each of the top and bottom
plates 114, 115 adjacent to the side plate 116. The left sidewall
123 of the first wick structure 12 forms a C-shaped isolated
portion 126 isolated from the inner surface of the casing 11.
[0023] The first wick structure 13 is disposed at a left inner side
of the casing 11 within the condenser section 113. The top wall
131, the bottom wall 132 and the left sidewall 133 of the first
wick structure 13 cooperatively form a U-shaped contact portion in
contact with an inner surface of the casing 11. In particular, the
contacting inner surface of the casing 11 includes the side plate
117, and a portion of each of the top and bottom plates 114, 115
adjacent to the side plate 117. The right sidewall 134 of the first
wick structure 13 forms a C-shaped isolated portion 136 isolated
from the inner surface of the casing 11. The left sidewall 123 of
the first wick structure 12, the right sidewall 134 of the first
wick structure 13 and the inner surface of the casing 11
cooperatively define a second vapor channel 142 therebetween. In
other words, the isolated portions 126, 136 and the inner surface
of the casing 11 cooperatively define the second vapor channel 142
therebetween. An end of the second vapor channel 142 communicates
with an end of the first vapor channel 141. The first and second
vapor channels 141, 142 cooperatively provide a passage through
which the vapor flows from the evaporator section 111 to the
condenser section 113. The isolated portions 126, 136 of the first
wick structures 12, 13 face a center of the casing 11.
[0024] Referring also to FIG. 4, the first wick structures 12, 13
extend longitudinally in the condenser section 113 to the second
wick structure 14, and join the second wick structure 14 at the
joint 149 between the evaporator section 111 and the condenser
section 113 via sintering. The first and second wick structures 12,
13, 14 cooperatively form a composite wick structure 17 in the
casing 11. A diameter of the inner space 140 of each first wick
structure 12, 13 exceeds a thickness of a circumferential wall of
the second wick structure 14 as measured in a horizontal direction
of the casing 11. The second wick structure 14 blocks a portion of
the end of the inner space 140 of each first wick structure 12, 13
at the joint 149. The inner spaces 140 of the first wick structures
12, 13 and the second vapor channel 142 between the first wick
structures 12, 13 all communicate with the first vapor channel
141.
[0025] The working medium is saturated in the first and second wick
structures 12, 13, 14. The working medium is usually selected from
a liquid such as water, methanol, or alcohol, which has a low
boiling point. The casing 11 of the heat pipe 10 is evacuated and
hermetically sealed after the working medium is injected into the
casing 11 and saturated in the first and second wick structures 12,
13, 14. Thus, the working medium can easily evaporate when it
receives heat at the evaporator section 111 of the heat pipe
10.
[0026] In operation, the evaporator section 111 of the heat pipe 10
is placed in thermal contact with a heat source (not shown) that
needs to be cooled. The heat source can, for example, be a central
processing unit (CPU) of a computer. The working medium contained
in the evaporator section 111 of the heat pipe 10 is vaporized when
receiving heat generated by the heat source. The generated vapor
moves from the evaporator section 111 via the vapor channels 141,
142 to the condenser section 113. After the vapor releases its heat
and condenses in the condenser section 113, the condensate is
returned by the first and second wick structures 12, 13, 14 to the
evaporator section 111 of the heat pipe 10, where the condensate is
again available for evaporation.
[0027] In the heat pipe 10, the first and second wick structures
12, 13, 14 cooperatively form the composite wick structure 17 in
the casing 11. This increases capillary force, and reduces flow
resistance and heat resistance. As a result, the condensate is
returned to the evaporator section 111 of the heat pipe 10 rapidly,
thus preventing potential drying out at the evaporator section 111.
In addition, the first and second wick structures 12, 13, 14 are
only located in the condenser section 113 and the evaporator
section 111, respectively. This enlarges the first and second vapor
channels 141, 142 in the evaporator and condenser sections section
111, 113, and further promotes the flow of the working medium in
the heat pipe 10. Furthermore, the first wick structures 12, 13 are
joined to the second wick structure 14 at the joint 149 via
sintering. Thus, the first wick structures 12, 13 closely and
continuously connect with the second wick structure 14, and the
working medium can be rapidly saturated in the second wick
structure 14 after returning to the evaporator section 111 via the
first wick structures 12, 13. Additionally, the first wick
structures 12, 13 cannot move freely in the casing 11. This
increases the flow of the working media in the casing 11, and
improves the heat transfer performance of the heat pipe 10.
[0028] Referring to FIG. 5, a heat pipe 20 in accordance with a
second embodiment of the disclosure is shown. The heat pipe 20
differs from the heat pipe 10 of the first embodiment only in that
there is only one first wick structure 22. The first wick structure
22 is disposed in a center of the casing 11 within the condenser
section 213.
[0029] At the condenser section 213 of the heat pipe 20, top and
bottom walls 221, 222 of the first wick structure 22 form two
contact portions in contact with the inner surface of the casing
11, respectively. In particular, the contacting inner surface of
the casing 11 includes the top and bottom plates 114, 115. Two
sidewalls 223, 224 of the first wick structure 22 form two isolated
portions isolated from the inner surface of the casing 11,
respectively. Two passages 2421, 2422 are respectively defined
between the sidewalls 223, 224 of the first wick structure 22 and
the inner surface of the casing 11, the passages 2421, 2422 being
disposed beside opposite sides of the first wick structure 22,
respectively. The two passages 2421, 2422 cooperatively form a
second vapor channel 242. Ends of the passages 2421, 2422
communicate with an end of the first vapor channel 141 of the
second wick structure 14.
[0030] Referring to FIG. 6, a heat pipe 30 in accordance with a
third embodiment of the disclosure is shown. The heat pipe 30
differs from the heat pipe 10 of the first embodiment only in that
another first wick structure 35 is deployed in a center of the
casing 11, for a total of three first wick structures 12, 13, 35.
The first wick structures 12, 13, 35 are spaced from each other.
The first wick structure 35 is the same as the first wick structure
22 of the second embodiment.
[0031] At the condenser section 313 of the heat pipe 30, the right
sidewall 134 of the first wick structure 13, the left sidewall 353
of the first wick structure 35, and the inner surface of the casing
11 cooperatively define a passage 3421 therebetween. The left
sidewall 123 of the first wick structure 12, the right sidewall 354
of the first wick structure 35, and the inner surface of the casing
11 cooperatively define another passage 3422 therebetween. The two
passages 3421, 3422 cooperatively form a second vapor channel 342.
Ends of the passages 3421, 3422 communicate with an end of the
first vapor channel 141 of the second wick structure 14.
[0032] Referring to FIG. 7, a heat pipe 40 in accordance with a
third embodiment of the disclosure is shown. The heat pipe 40
differs from the heat pipe 10 of the first embodiment only in that
a second wick structure 44 contacts a portion of the inner surface
of the casing 11 at the evaporator section 411 which corresponds to
an area of an outside of the casing 11 designated for contacting a
heat-generating electronic component 70. In particular, the second
wick structure 44 is plate-shaped, and contacts an inner surface of
the bottom plate 115 of the casing 11. The electronic component 70
contacts an outer surface of the bottom plate 115. The second wick
structure 44 and the inner surface of the casing 11 cooperatively
define a first vapor channel 441 therebetween. More particularly,
the second wick structure 44, the top plate 114 and the side plates
116, 117 cooperatively define the first vapor channel 441
therebetween.
[0033] In the heat pipe 40, the second wick structure 44 contacts a
portion of the casing 11 within the evaporator section 411
corresponding to the electronic component 70. This enlarges the
first vapor channel 441 in the evaporator section 411, and further
promotes the flow of the working medium in the heat pipe 40. In
addition, heat generated by the electronic component 70 can be
rapidly transferred to the second wick structure 44 by the casing
11, whereby the heat transfer performance of the heat pipe 40 is
improved.
[0034] It is to be understood, however, that even though numerous
characteristics and advantages of the present embodiments have been
set forth in the foregoing description, together with details of
the structures and functions of the embodiments, the disclosure is
illustrative only, and changes may be made in detail, especially in
matters of shape, size, and arrangement of parts within the
principles of the invention to the full extent indicated by the
broad general meaning of the terms in which the appended claims are
expressed.
* * * * *