U.S. patent application number 15/671038 was filed with the patent office on 2018-05-03 for heat radiation sheet and method for manufacturing of the same.
The applicant listed for this patent is SHINWHA INTERTEK CORP. Invention is credited to Cheol Heung AHN, Won Jae CHOI, Jin GO, Dong Hyun KIM, Hak-Soo KIM, Dae-Bok PARK, Su-Han WOO, Sung Chul YOON.
Application Number | 20180124957 15/671038 |
Document ID | / |
Family ID | 59222359 |
Filed Date | 2018-05-03 |
United States Patent
Application |
20180124957 |
Kind Code |
A1 |
YOON; Sung Chul ; et
al. |
May 3, 2018 |
Heat Radiation Sheet And Method For Manufacturing Of The Same
Abstract
Provided are heat radiation sheet and method of manufacturing
the same. The heat radiation sheet comprising: a first protective
layer; a first adhesive member which is disposed on the first
protective layer and has one or more through holes; a support
member which is disposed on the first adhesive member and has one
or more through holes; a second adhesive member which is disposed
on the support member and has one or more through holes; a heat
radiation member which is disposed on the second adhesive member
and has one or more through holes; and a third adhesive member
which is disposed on the heat radiation member and comprises a base
portion contacting a first surface of the heat radiation member and
protrusions protruding from the base portion and inserted into the
through holes of the heat radiation member, the through holes of
the second adhesive member, the through holes of the support member
and the through holes of the first adhesive member, wherein the
protrusions of the third adhesive member are at least partially
coupled to the first protective layer.
Inventors: |
YOON; Sung Chul;
(Gyeonggi-do, KR) ; AHN; Cheol Heung;
(Chungcheongnam-do, KR) ; KIM; Dong Hyun;
(Chungcheongnam-do, KR) ; KIM; Hak-Soo;
(Chungcheongbuk-do, KR) ; WOO; Su-Han; (Daejeon,
KR) ; GO; Jin; (Chungcheongnam-do, KR) ; CHOI;
Won Jae; (Gyeonggi-do, KR) ; PARK; Dae-Bok;
(Chungcheongnam-do, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SHINWHA INTERTEK CORP |
Chungcheongnam-do |
|
KR |
|
|
Family ID: |
59222359 |
Appl. No.: |
15/671038 |
Filed: |
August 7, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 23/36 20130101;
H01L 23/373 20130101; H01L 23/3735 20130101; F28F 13/18 20130101;
H05K 7/20963 20130101; H01L 23/3677 20130101 |
International
Class: |
H05K 7/20 20060101
H05K007/20 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 31, 2016 |
KR |
10-2016-0142797 |
Claims
1. A heat radiation sheet comprising: a first protective layer; a
first adhesive member which is disposed on the first protective
layer and has one or more through holes; a support member which is
disposed on the first adhesive member and has one or more through
holes; a second adhesive member which is disposed on the support
member and has one or more through holes; a heat radiation member
which is disposed on the second adhesive member and has one or more
through holes; and a third adhesive member which is disposed on the
heat radiation member and comprises a base portion contacting a
first surface of the heat radiation member and protrusions
protruding from the base portion and inserted into the through
holes of the heat radiation member, the through holes of the second
adhesive member, the through holes of the support member and the
through holes of the first adhesive member, wherein the protrusions
of the third adhesive member are at least partially coupled to the
first protective layer.
2. The heat radiation sheet of claim 1, wherein the through holes
of the first adhesive member, the through holes of the support
member, the through holes of the second adhesive member, and the
through holes of the heat radiation member are connected to each
other.
3. The heat radiation sheet of claim 2, wherein a thickness of the
first protective layer is greater than a thickness of the support
member and smaller than a thickness of the heat radiation member, a
thickness of the base portion of the third adhesive member is
greater than the sum of a thickness of the first adhesive member
and a thickness of the second adhesive member, thermal conductivity
of the heat radiation member in a horizontal direction is greater
than thermal conductivity of the first protective layer, and the
thermal conductivity of the first protective layer is greater than
thermal conductivity of the support member.
4. The heat radiation sheet of claim 2, wherein the heat radiation
member comprises a carbon material, and the first protective layer
comprises copper (Cu), aluminum (Al), silver (Ag), gold (Au),
carbon nanotubes, graphene, or a polymer film.
5. The heat radiation sheet of claim 4, wherein the first adhesive
member and the second adhesive member comprise thermosetting resin,
and the third adhesive member comprises photocurable resin.
6. The heat radiation member of claim 4, wherein a modulus of the
third adhesive member is greater than a modulus of the first
adhesive member and a modulus of the second adhesive member.
7. The heat radiation member of claim 1, wherein the protrusions of
the third adhesive member contact the first adhesive member.
8. The heat radiation member of claim 7, wherein the through holes
of the heat radiation member are arranged regularly on a plane.
9. The heat radiation sheet of claim 1, wherein a planar area of
each through hole of the heat radiation member in the first surface
of the heat radiation member facing the third adhesive member is
greater than a planar area of each through hole of the heat
radiation member in a second surface of the heat radiation member
facing the second adhesive member.
10. The heat radiation sheet of claim 9, wherein the planar area of
each through hole of the heat radiation member in the second
surface of the heat radiation member facing the second adhesive
member is greater than a planar area of each through hole of the
first adhesive member in a second surface of the first adhesive
member facing the first protective layer.
11. The heat radiation sheet of claim 1, further comprising a
second protective layer which is disposed on the third adhesive
member, wherein gloss of a second surface of the second protective
layer facing the third adhesive member is equal to gloss of a first
surface of the first protective layer facing the first adhesive
member.
12. The heat radiation sheet of claim 1, further comprising a
second protective layer which is disposed on the third adhesive
member, wherein gloss of a second surface of the second protective
layer facing the third adhesive member is smaller than gloss of a
first surface of the first protective layer facing the first
adhesive member.
13. The heat radiation sheet of claim 1, further comprising: a
second protective layer which is disposed on the third adhesive
member; and a metal particle layer which is disposed on a second
surface of the second protective layer facing the third adhesive
member.
14. A heat radiation sheet comprising: a protective layer; a first
adhesive member which is disposed on the protective layer and has
one or more through holes; a heat radiation member which is
disposed on the first adhesive member and has one or more through
holes; and a second adhesive member which is disposed on the heat
radiation member and comprises a base portion contacting a first
surface of the heat radiation member and protrusions protruding
from the base portion and inserted into the through holes of the
heat radiation member and the through holes of the first adhesive
member, wherein the first adhesive member and the second adhesive
member are made of different materials wherein the protrusions of
the second adhesive member are at least partially coupled to the
protective layer.
15. A method of manufacturing a heat radiation sheet, the method
comprising: preparing a carrier film, a first adhesive member
disposed on a first surface of the carrier film, and a heat
radiation member disposed on a first surface of the first adhesive
member; forming one or more through holes in each of the heat
radiation member and the first adhesive member; removing the
carrier film and placing a first protective layer on a second
surface of the first adhesive member; and placing a second adhesive
member on the heat radiation member such that the second adhesive
member contacts the first protective layer and the heat radiation
member, wherein the second adhesive member is at least partially
coupled to the first protective layer.
16. The method of claim 15, wherein the placing of the second
adhesive member comprises: providing a composition for forming the
second adhesive member on a first surface of the heat radiation
member; filling the through holes of the heat radiation member with
the composition; and forming the second adhesive member by curing
the composition.
17. The method of claim 15, further comprising: placing a release
film on the first surface of the second adhesive member; pressing
the first protective layer, the first adhesive member, the heat
radiation member, the second adhesive member, and the release film;
exposing the first surface of the second adhesive member by
removing the release film; and placing a second protective layer on
the first surface of the second adhesive member, wherein the
placing of the release film, the pressing of the release film, the
removing of the release film, and the placing of the second
protective layer are performed using a roll-to-roll process.
Description
[0001] This application claims priority to Korean Patent
Application No. 10-2016-0142797, filed on Oct. 31, 2016, in the
Korean Intellectual Property Office, and all the benefits accruing
therefrom under 35 U.S.C. .sctn. 119, the disclosure of which in
its entirety is incorporated by reference.
BACKGROUND
1. Field
[0002] The present inventive concept relates to a heat radiation
sheet and a method of manufacturing the same.
2. Description of the Related Art
[0003] Heat may be generated in an electronic device by electronic
parts such as wirings, terminals, and chips. Heat generated by
electronic parts may shorten the lifetime of electronic devices and
cause malfunction and performance degradation. In particular, in
the case of a display device having a light source that generates a
large amount of heat, the accumulated heat is a major cause of
deterioration of the display quality of the display device.
[0004] As electronic devices such as display devices and portable
terminals become more sophisticated and miniaturized, electronic
parts included in the electronic devices are becoming highly
integrated, which, in turn, increases heat density. Therefore,
there is a need for a technology that can effectively remove
generated heat.
[0005] As an example method of removing the heat, a heat radiation
sheet including a heat radiation member may be placed adjacent to
an electronic part that generates heat.
SUMMARY
[0006] Aspects of the inventive concept provide a heat radiation
sheet having an improved heat dissipation function and superior
bending characteristics and durability.
[0007] Aspects of the inventive concept also provide a method of
manufacturing a heat radiation sheet having an improved heat
dissipation function and superior bending characteristics and
durability.
[0008] However, aspects of the inventive concept are not restricted
to the one set forth herein. The above and other aspects of the
inventive concept will become more apparent to one of ordinary
skill in the art to which the inventive concept pertains by
referencing the detailed description of the inventive concept given
below.
[0009] According to an exemplary embodiment of the invention, there
is provided a heat radiation sheet. The heat radiation sheet
comprising: a first protective layer; a first adhesive member which
is disposed on the first protective layer and has one or more
through holes; a support member which is disposed on the first
adhesive member and has one or more through holes; a second
adhesive member which is disposed on the support member and has one
or more through holes; a heat radiation member which is disposed on
the second adhesive member and has one or more through holes; and a
third adhesive member which is disposed on the heat radiation
member and comprises a base portion contacting a first surface of
the heat radiation member and protrusions protruding from the base
portion and inserted into the through holes of the heat radiation
member, the through holes of the second adhesive member, the
through holes of the support member and the through holes of the
first adhesive member, wherein the protrusions of the third
adhesive member are at least partially coupled to the first
protective layer.
[0010] In an exemplary embodiment, wherein the through holes of the
first adhesive member, the through holes of the support member, the
through holes of the second adhesive member, and the through holes
of the heat radiation member may be connected to each other.
[0011] In an exemplary embodiment, a thickness of the first
protective layer may be greater than a thickness of the support
member and smaller than a thickness of the heat radiation member, a
thickness of the base portion of the third adhesive member may be
greater than the sum of a thickness of the first adhesive member
and a thickness of the second adhesive member, thermal conductivity
of the heat radiation member in a horizontal direction may be
greater than thermal conductivity of the first protective layer,
and the thermal conductivity of the first protective layer may be
greater than thermal conductivity of the support member.
[0012] In an exemplary embodiment, the heat radiation member may
comprise a carbon material, and the first protective layer
comprises copper (Cu), aluminum (Al), silver (Ag), gold (Au),
carbon nanotubes, graphene, or a polymer film.
[0013] In an exemplary embodiment, the first adhesive member and
the second adhesive member may comprise thermosetting resin, and
the third adhesive member comprises photocurable resin.
[0014] In an exemplary embodiment, a modulus of the third adhesive
member may be greater than a modulus of the first adhesive member
and a modulus of the second adhesive member.
[0015] In an exemplary embodiment, the protrusions of the third
adhesive member may contact the first adhesive member.
[0016] In an exemplary embodiment, the through holes of the heat
radiation member may be arranged regularly on a plane.
[0017] In an exemplary embodiment, a planar area of each through
hole of the heat radiation member in the first surface of the heat
radiation member facing the third adhesive member may be greater
than a planar area of each through hole of the heat radiation
member in a second surface of the heat radiation member facing the
second adhesive member.
[0018] In an exemplary embodiment, the planar area of each through
hole of the heat radiation member in the second surface of the heat
radiation member facing the second adhesive member may be greater
than a planar area of each through hole of the first adhesive
member in a second surface of the first adhesive member facing the
first protective layer.
[0019] In an exemplary embodiment, the heat radiation sheet may
further comprise a second protective layer which is disposed on the
third adhesive member, wherein gloss of a second surface of the
second protective layer facing the third adhesive member is equal
to gloss of a first surface of the first protective layer facing
the first adhesive member.
[0020] In an exemplary embodiment, the heat radiation sheet may
further comprise a second protective layer which is disposed on the
third adhesive member, wherein gloss of a second surface of the
second protective layer facing the third adhesive member is smaller
than gloss of a first surface of the first protective layer facing
the first adhesive member.
[0021] In an exemplary embodiment, the heat radiation sheet may
further comprise: a second protective layer which is disposed on
the third adhesive member; and a metal particle layer which is
disposed on a second surface of the second protective layer facing
the third adhesive member.
[0022] According to another exemplary embodiment of the invention,
there is provided a heat radiation sheet. The heat radiation sheet
comprising: a protective layer; a first adhesive member which is
disposed on the protective layer and has one or more through holes;
a heat radiation member which is disposed on the first adhesive
member and has one or more through holes; and a second adhesive
member which is disposed on the heat radiation member and comprises
a base portion contacting a first surface of the heat radiation
member and protrusions protruding from the base portion and
inserted into the through holes of the heat radiation member and
the through holes of the first adhesive member, wherein the first
adhesive member and the second adhesive member are made of
different materials, wherein the protrusions of the second adhesive
member are at least partially coupled to the protective layer.
[0023] According to an exemplary embodiment of the invention, there
is provided a method of manufacturing a heat radiation sheet. The
method comprising: preparing a carrier film, a first adhesive
member disposed on a first surface of the carrier film, and a heat
radiation member disposed on a first surface of the first adhesive
member; forming one or more through holes in each of the heat
radiation member and the first adhesive member; removing the
carrier film and placing a first protective layer on a second
surface of the first adhesive member; and placing a second adhesive
member on the heat radiation member such that the second adhesive
member contacts the first protective layer and the heat radiation
member, wherein the second adhesive member is at least partially
coupled to the first protective layer.
[0024] In an exemplary embodiment, the placing of the second
adhesive member may comprise: providing a composition for forming
the second adhesive member on a first surface of the heat radiation
member; filling the through holes of the heat radiation member with
the composition; and forming the second adhesive member by curing
the composition.
[0025] In an exemplary embodiment, may further comprise: placing a
release film on the first surface of the second adhesive member;
pressing the first protective layer, the first adhesive member, the
heat radiation member, the second adhesive member, and the release
film; exposing the first surface of the second adhesive member by
removing the release film; and placing a second protective layer on
the first surface of the second adhesive member, wherein the
placing of the release film, the pressing of the release film, the
removing of the release film, and the placing of the second
protective layer are performed using a roll-to-roll process.
[0026] A heat radiation sheet according to an embodiment can have
superior heat dissipation characteristics and improved bending
characteristics. In addition, even when a graphite sheet is used as
a heat radiation member, interlaminar adhesion of the graphite
sheet can be increased, thereby giving excellent physical and
mechanical properties to the heat radiation sheet and improving the
reliability of the heat radiation sheet.
[0027] A method of manufacturing a heat radiation sheet according
to an embodiment is performed using a roll-to-roll process.
Therefore, the manufacturing process can be simplified, and the
manufacturing cost can be reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] These and/or other aspects will become apparent and more
readily appreciated from the following description of the
embodiments, taken in conjunction with the accompanying drawings in
which:
[0029] FIG. 1 is an exploded perspective view of a heat radiation
sheet according to an embodiment;
[0030] FIG. 2 is a cross-sectional view taken along the line II-II'
of FIG. 1;
[0031] FIG. 3 is an exploded perspective view of a heat radiation
sheet according to an embodiment;
[0032] FIGS. 4 through 6 are cross-sectional views of heat
radiation sheets according to embodiments;
[0033] FIGS. 7 through 13 are views illustrating a method of
manufacturing a heat radiation sheet according to an
embodiment;
[0034] FIG. 14 is a photograph of a heat radiation sheet
manufactured according to Example; and
[0035] FIG. 15 illustrates the results of Experimental Example.
DETAILED DESCRIPTION
[0036] Features of the invention and methods of accomplishing the
same may be understood more readily by reference to the following
detailed description of preferred embodiments and the accompanying
drawings. The invention may, however, be embodied in many different
forms and should not be construed as being limited to the
embodiments set forth herein. Rather, these embodiments are
provided so that this disclosure will be thorough and complete and
will fully convey the concept of the invention to those skilled in
the art, and the invention will only be defined by the appended
claims.
[0037] It will be understood that when an element or layer is
referred to as being "on," "connected to" or "coupled to" another
element or layer, the element or layer can be directly on,
connected or coupled to another element or layer or intervening
elements or layers. In contrast, when an element is referred to as
being "directly on," "directly connected to" or "directly coupled
to" another element or layer, there are no intervening elements or
layers present. As used herein, connected may refer to elements
being physically, electrically and/or fluidly connected to each
other.
[0038] Like numbers refer to like elements throughout. As used
herein, the term "and/or" includes any and all combinations of one
or more of the associated listed items.
[0039] It will be understood that, although the terms first,
second, third, etc., may be used herein to describe various
elements, components, regions, layers and/or sections, these
elements, components, regions, layers and/or sections should not be
limited by these terms. These terms are only used to distinguish
one element, component, region, layer or section from another
element, component, region, layer or section. Thus, a first
element, component, region, layer or section discussed below could
be termed a second element, component, region, layer or section
without departing from the teachings of the invention.
[0040] Spatially relative terms, such as "below," "lower," "under,"
"above," "upper" and the like, may be used herein for ease of
description to describe the relationship of one element or feature
to another element(s) or feature(s) as illustrated in the figures.
It will be understood that the spatially relative terms are
intended to encompass different orientations of the device in use
or operation, in addition to the orientation depicted in the
figures. For example, if the device in the figures is turned over,
elements described as "below" or "beneath" relative to other
elements or features would then be oriented "above" relative to the
other elements or features. Thus, the exemplary term "below" can
encompass both an orientation of above and below. The device may be
otherwise oriented (rotated 90 degrees or at other orientations)
and the spatially relative descriptors used herein interpreted
accordingly.
[0041] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting. As
used herein, the singular forms "a," "an" and "the" are intended to
include the plural forms as well, including "at least one," unless
the context clearly indicates otherwise. It will be further
understood that the terms "comprises," "comprising," "includes"
and/or "including," when used in this specification, specify the
presence of stated features, integers, operations, elements, and/or
components, but do not preclude the presence or addition of one or
more other features, integers, steps, operations, elements,
components, and/or groups thereof. "At least one" is not to be
construed as limiting "a" or "an," "Or" means "and/or." As used
herein, the term "and/or" includes any and all combinations of one
or more of the associated listed items.
[0042] The terms "sheet," "film," and "plate" used herein have the
same meaning and can be used interchangeably. In this
specification, a first direction X is any one direction in a plane,
a second direction Y is a direction intersecting the first
direction X in the plane, and a third direction Z is a direction
perpendicular to the plane.
[0043] Hereinafter, embodiments of the inventive concept will be
described with reference to the accompanying drawings.
[0044] FIG. 1 is an exploded perspective view of a heat radiation
sheet 1000 according to an embodiment. FIG. 2 is a cross-sectional
view taken along the line II-II'' of FIG. 1.
[0045] Referring to FIGS. 1 and 2, the heat radiation sheet 1000
according to the current embodiment includes a first protective
layer 110, a first adhesive member 210 disposed on the first
protective layer 110, a support member 310 disposed on the first
adhesive member 210, a second adhesive member 220 disposed on the
support member 310, a heat radiation member 410 disposed on the
second adhesive member 220, a third adhesive member 230 disposed on
the heat radiation member 410, and a second protective layer 120
disposed on the third adhesive member 230.
[0046] The first protective layer 110 and the second protective
layer 120 may be protective members that support the heat radiation
member 410 to minimize damage due to an external impact and to
prevent the penetration of impurities, such as moisture, into the
heat radiation sheet 1000. The first protective layer 110 and the
second protective layer 120 may be made of a material having a
relatively high thermal conductivity. That is, the first protective
layer 110 and the second protective layer 120 may be heat transfer
members as well as protective members. For example, each of the
first protective layer 110 and the second protective layer 120 may
be made of a metal material such as copper (Cu), aluminum (Al),
silver (Ag), gold (Au) or an alloy of the same or may be made of
carbon nanotubes or graphene. Another example of each of the first
protective layer 110 and the second protective layer 120 may be a
polymer film such as polyethylene terephthalate. In an exemplary
embodiment, the thermal conductivity of each of the first
protective layer 110 and the second protective layer 120 may be
equal to or greater than about 100 W/mK. The first protective layer
110 and the second protective layer 120 may be made of a material
having a relatively high thermal conductivity to further improve
heat dissipation characteristics of the heat radiation sheet 1000.
A maximum thickness t.sub.110 of the first protective layer 110 and
a maximum thickness t.sub.120 of the second protective layer 120
may each be, but are not limited to, about 7 to 75
micrometer(.mu.m) or about 7 to 36 .mu.m.
[0047] In an exemplary embodiment, the surface roughness of a
second surface (a lower surface in the drawings) of the second
protective layer 120 which faces the third adhesive member 230 may
be greater than that of a first surface (an upper surface in the
drawings) of the first protective layer 110 which faces the first
adhesive member 210. In a method of manufacturing a heat radiation
sheet which will be described later, an attachment surface of the
first protective layer 110 attached using a sheet type adhesive
member may be formed to have a relatively small surface roughness,
and an attachment surface of the second protective layer 120
attached using a composition for forming an adhesive member may be
formed to have a relatively large surface roughness, thereby
improving the durability of the heat radiation sheet 1000.
[0048] The surface gloss of the second surface of the second
protective layer 120 which faces the third adhesive member 230 may
be smaller than the gloss of the first surface of the first
protective layer 110 which faces the first adhesive member 210. As
used herein, the term "gloss" denotes a ratio of the amount of
regularly reflected light to the amount of light incident at an
angle of 60 degrees to a reflective surface. The gloss may have a
smaller value as the surface roughness is greater. For example, the
gloss of the second surface (the lower surface in the drawings) of
the second protective layer 120 may be about 50 or less, about 20
or less, or about 10 or less. If the gloss of the second surface of
the second protective layer 120 is less than 50, the surface
roughness of the second surface of the second protective layer 120
may be made sufficiently high, thereby improving the durability of
the heat radiation sheet 1000. In addition, the gloss of the first
surface of the first protective layer 110 may be greater than the
gloss of the second surface of the second protective layer 120 by
about 20 or more.
[0049] The heat radiation member 410 is interposed between the
first protective layer 110 and the second protective layer 120. The
heat radiation member 410 may be a heat transfer member made of a
material having a relatively high thermal conductivity. In an
exemplary embodiment, the thermal conductivity of the heat
radiation member 410 in a thickness direction (the third direction
Z) may be different from the thermal conductivity of the heat
radiation member 410 in a horizontal direction (the first direction
X and the second direction Y). For example, the thermal
conductivity of the heat radiation member 410 may be greater in the
horizontal direction than in the thickness direction. Accordingly,
the heat transferred from the outside can be effectively
transmitted in the horizontal direction (a plane direction). In an
exemplary embodiment, the magnitude of the thermal conductivity of
the heat radiation member 410 in the horizontal direction may be at
least about 20 times the magnitude of the thermal conductivity of
the heat radiation member 410 in the thickness direction. For
example, the thermal conductivity of the heat radiation member 410
in the horizontal direction may be about 450 W/mK, and the thermal
conductivity of the heat radiation member 410 in the thickness
direction may be about 15 W/mK.
[0050] In addition, the thermal conductivity of the heat radiation
member 410 may be greater than the thermal conductivity of the
first protective layer 110 and the thermal conductivity of the
second protective layer 120. For example, the thermal conductivity
of the heat radiation member 410 in the horizontal direction may be
greater than the thermal conductivity of the first protective layer
110 and the thermal conductivity of the second protective layer
120.
[0051] The heat radiation member 410 may include a carbon material
such as graphite, graphene, or carbon nanotubes. In an exemplary
embodiment, the heat radiation member 410 may be a graphite film
obtained by carbonizing and graphitizing a polymer film such as
polyimide. Due to its excellent thermal conductivity, the graphite
can further improve the heat dissipation characteristics of the
heat radiation sheet 1000 when applied as the heat radiation member
410. In addition, artificial graphite produced by carbonizing and
graphitizing a polymer film can make the heat radiation sheet 1000
thin because it can be formed to a micro-sized thickness. When the
artificial graphite is applied as the heat radiation member 410,
the adhesive strength of the heat radiation member 410 in the
thickness direction may be smaller than the adhesive or adhesive
strength of the first adhesive member 210.
[0052] A thickness t.sub.410 of the heat radiation member 410 may
be greater than the maximum thickness t.sub.110 of the first
protective layer 110 and the maximum thickness t.sub.120 of the
second protective layer 120. For example, the thickness t.sub.410
of the heat radiation member 410 may be about 17 to 40 .mu.m. In an
embodiment, the heat radiation member 410 may be natural
graphite.
[0053] The heat radiation member 410 has one or more first through
holes 410h. Protrusions 230b of the third adhesive member 230 which
will be described later may be inserted into the first through
holes 410h. The first through holes 410h may be regularly arranged
on a plane. In this specification, the phrase "on a plane" or "a
planar viewpoint" refers to a case where an object is viewed in the
third direction Z in the drawings. In an exemplary embodiment, the
first through holes 410h of the heat radiation member 410 may be
separated from each other in the first direction X and the second
direction Y, which are orthogonal to each other on a plane, and may
be arranged in a substantially matrix shape. A distance d.sub.1
between the first through holes 410h in the first direction X may
be different from a distance d.sub.2 between the first through
holes 410h in the second direction Y. For example, the distance
d.sub.1 between the first through holes 410h in the first direction
X may be about 15 to 30 mm, the distance d.sub.2 between the first
through holes 410h in the second direction Y may be about 5 to 20
me, and the distance d.sub.1 in the first direction X may be
greater than the distance d.sub.2 in the second direction Y. Since
the first through holes 410h are substantially regularly arranged
on a plane, the thermal conductivity of the heat radiation member
410 in the horizontal direction can be uniformly maintained. In an
embodiment, the distance d.sub.1 between the first through holes
410h in the first direction X may be substantially equal to the
distance d.sub.2 between the first through holes 410h in the second
direction Y.
[0054] The planar shape of each of the first through holes 410h is
not particularly limited, but may be, for example, substantially
circular. In an embodiment, the planar shape of each of the first
through holes 410h may be oval or polygonal. In this specification,
the planar shape of a through hole denotes the cross-sectional
shape of the through hole taken along a direction perpendicular to
the third direction Z. When the first through holes 410h are
circular, a diameter d.sub.3 of each of the first through holes
410h may be smaller than the distances d.sub.1 and d.sub.2 in the
first direction X and the second direction Y. For example, the
diameter d.sub.3 of each of the first through holes 410h may be
about 2 to 6 millimeter(mm).
[0055] The first through holes 410h may extend in substantially the
third direction Z (the thickness direction). The planar area of
each of the first through holes 410h may be substantially uniform
regardless of position in the third direction Z. In this
specification, the planar area of a through hole refers to the area
of a figure having a shape corresponding to the planar shape of the
through hole. For example, the planar area of each of the first
through holes 410h in a first surface (an upper surface in the
drawings) of the heat radiation member 410 which faces the third
adhesive member 230 may be substantially equal to the planar area
of each of the first through holes 410h in a second surface (a
lower surface in the drawings) of the heat radiation member 410
which faces the second adhesive member 220. In addition, inner
walls of the first through holes 410h may be substantially
perpendicular to any one surface of the heat radiation member 410.
However, in an embodiment, the first through holes 410h may be
inclined.
[0056] The first adhesive member 210 may be disposed between the
first protective layer 110 and the heat radiation member 410 to be
in direct contact with the first protective layer 110. In addition,
the second adhesive member 220 may be disposed between the first
protective layer 110 and the heat radiation member 410 to be in
direct contact with the heat radiation member 410. Each of the
first adhesive member 210 and the second adhesive member 220 may
include a material having adhesive or adhesive strength. The first
adhesive member 210 and the second adhesive member 220 can bond the
first protective layer 110 to the second surface (the lower surface
in the drawings) of the heat radiation member 410. The first
protective layer 110 attached onto the second surface of the heat
radiation member 410 can improve heat transfer characteristics
and/or durability of the heat dissipating sheet 1000. Also, for
example, even when the heat radiation member 410 is made of a
material that is susceptible to damage in the third direction Z and
is easily peeled off, the first protective layer 110 can improve
the internal adhesion in the vicinity of the second surface (the
lower surface in the drawings) of the heat radiation member 410
facing the first protection layer 110 and give excellent physical
and mechanical properties to the heat radiation sheet 1000.
[0057] In addition, the support member 310 may be disposed between
the first adhesive member 210 and the second adhesive member 220 to
be in direct contact with the first adhesive member 210 and the
second adhesive member 220. In the method of manufacturing a heat
radiation sheet which will be described later, the support member
310 can make it easy to form the first through holes 410h of the
heat radiation member 410 and second through fourth through holes
220h, 310h and 210h which will be described later.
[0058] A thickness t.sub.310 of the support member 310 may be
smaller than the maximum thickness t.sub.110 of the first
protective layer 110 and the maximum thickness t.sub.120 of the
second protective layer 120. In addition, a thickness t.sub.210 of
the first adhesive member 210 and a thickness t.sub.220 of the
second adhesive member 220 may both be smaller than the maximum
thickness t.sub.110 of the first protective layer 110 and the
maximum thickness t.sub.120 of the second protective layer 120. For
example, the thickness t.sub.210 of the first adhesive member 210,
the thickness t.sub.220 of the second adhesive member 220, and the
thickness t.sub.310 of the support member 310 may each be about 0.5
to 2 .mu.m. The thermal conductivity of the support member 310 may
be smaller than those of the first protective layer 110, the second
protective layer 120, and the heat radiation member 410. The
support member 310 can be made of any material as long as it is
more rigid than the first adhesive member 210 and the second
adhesive member 220. For example, the support member 310 may be a
polymer film such as polyethylene terephthalate (PET). The first
adhesive member 210 and the second adhesive member 220 may include
thermosetting resin.
[0059] Unlike the illustration in the drawings, the support member
310 and the second adhesive member 220 may be omitted in an
embodiment. In this case, the first adhesive member 210 may
directly contact both the first protective layer 110 and the heat
radiation member 410 to bond the first protective layer 110 and the
heat radiation member 410 together.
[0060] The second adhesive member 220 has one or more second
through holes 220h, the support member 310 has one or more third
through holes 310h, and the first adhesive member 210 has one or
more fourth through holes 210h. The protrusions 230b of the third
adhesive member 230 to be described later may be inserted into the
second through holes 220h, the third through holes 310h and the
fourth through holes 210h. The first through holes 410h of the heat
radiation member 410, the second through holes 220h of the second
adhesive member 220, the third through holes 310h of the support
member 310 and the fourth through holes 210h of the first adhesive
member 210 may be connected to each other. The second through
fourth through holes 220h, 310h and 210h may be regularly arranged
on a plane, and the planar shape, size and arrangement of the
second through fourth through holes 220h, 310h and 210h may be
substantially the same as those of the first through holes 410h.
The second through fourth through holes 220h, 310h and 210h may
extend in substantially the third direction Z, and respective inner
walls of the second through fourth through holes 220h, 310h and
210h may be substantially perpendicular to the first surface of the
first protective layer 110.
[0061] The third adhesive member 230 may be disposed on the heat
radiation member 410. In an exemplary embodiment, the third
adhesive member 230 includes a base portion 230a which is disposed
on the heat radiation member 410 to contact the first surface (the
upper surface in the drawings) of the heat radiation member 410 and
one or more protrusions 230b which protrude from the base portion
230a to a side (a lower side in the drawings) in the third
direction Z and are inserted into the first through fourth through
holes 410h, 220h, 310h and 210h. The base portion 230a and the
protrusions 230b may be integrally formed with each other without a
physical boundary.
[0062] The base portion 230a and the protrusions 230b of the third
adhesive member 230 may all include a material having adhesive or
adhesive strength. In an exemplary embodiment, the third adhesive
member 230 may be made of a material different from the first
adhesive member 210 and the second adhesive member 220. For
example, the third adhesive member 230 may include a material
having greater bonding or adhesive strength than the first adhesive
member 210. In another example, the third adhesive member 230 may
include photocurable resin. The third adhesive member 230 may be
made of photocurable resin to minimize the volume lost during a
curing process. Accordingly, the protrusions 230b can be inserted
completely into the through holes. The viscosity of the third
adhesive member 230 may be in the range of about 100 to 10,000 cps,
about 100 to 5,000 cps, or about 1,000 to 5,000 cps. In the method
of manufacturing a heat radiation sheet which will be described
later, the third adhesive member 230 may be formed to have a
relatively low viscosity so as to make it easy to form the
protrusions 230b of the third adhesive member 230. The thermal
conductivity of the third adhesive member 230 may be smaller than
the thermal conductivity of the heat radiation member 410.
[0063] The modulus of the third adhesive member 230 may be greater
than the modulus of the first adhesive member 210 and the modulus
of the second adhesive member 220. In addition, a minimum thickness
t.sub.230a of the base portion 230a of the third adhesive member
230 may be greater than the sum (t.sub.210+t.sub.220) of the
thickness t.sub.210 of the first adhesive member 210 and the
thickness t.sub.220 of the second adhesive member 220. Since the
base portion 230a of the third adhesive member 230 having a
relatively large modulus is formed to have a sufficient thickness,
bending characteristics of the heat radiation sheet 1000 can be
improved. In particular the first adhesive member 210 and the
second adhesive member 220 are disposed on a first side (a lower
side in the drawings) of the heat radiation member 410, the base
portion 230a of the third adhesive member 230 is disposed on a
second side (an upper side in the drawings) of the heat radiation
member 410, and the protrusions 230b penetrating the heat radiation
member 410 are connected to the base portion 230a. Accordingly, the
minimum thickness t.sub.230a of the base portion 230a of the third
adhesive member 230 is made greater than the sum
(t.sub.210+t.sub.220) of the thickness t.sub.210 of the first
adhesive member 210 and the thickness t.sub.220 of the second
adhesive member 220, thereby further improving the bending
characteristics. For example, the minimum thickness t.sub.230a of
the base portion 230a of the third adhesive member 230 may be about
3 to 6 .mu.m.
[0064] In some embodiments, the third adhesive member 230 may
include a plurality of thermally conductive particles (not
illustrated) dispersed therein. That is, the base portion 230a and
the protrusions 230b of the third adhesive member 230 may include a
material having adhesive or bonding strength and a plurality of
thermally conductive particles dispersed therein. The thermally
conductive particles can give heat transfer characteristics to the
third adhesive member 230 and further improve the heat transfer
characteristics of the heat radiation sheet 1000. Examples of the
thermally conductive particles include metal particles, particles
made of a carbon material, and particles made of a polymer
material.
[0065] The base portion 230a of the third adhesive member 230 may
bond the second protective layer 120 to the first surface (the
upper surface in the drawings) of the heat radiation member 410.
The second protective layer 120 attached onto the first surface of
the heat radiation member 410 can improve the heat transfer
characteristics and/or durability of the heat radiation sheet
1000). In addition, for example, even when the heat radiation
member 410 is made of a material that is susceptible to damage in
the third direction Z and is easily peeled off, the second
protective layer 120 can improve the internal adhesion in the
vicinity of the first surface (the upper surface in the drawings)
of the heat radiation member 410 facing the second protective layer
120 and give excellent physical and mechanical properties to the
heat radiation sheet 1000.
[0066] The protrusions 230b of the third adhesive member 230 may
protrude from the base portion 230a to the first side (the lower
side in the drawings) in the third direction Z. The protrusions
230b may be arranged on a plane in a form corresponding to the
arrangement of in the first through fourth through holes 410h,
220h, 310h and 210h and may fill the first through fourth through
holes 410h, 220h, 310h and 210h.
[0067] The protrusions 230b of the third adhesive member 230 may be
inserted into the first through fourth through holes 410h, 220h,
310h and 210h to be in direct contact with the inner walls of the
first through fourth through holes 410h, 220h, 310h and 210h and
the first surface (the upper surface in the drawings) of the first
protective layer 110. That is, the protrusions 230b of the third
adhesive member 230 may contact all of the heat radiation member
410, the second adhesive member 220, the support member 310, the
first adhesive member 210, and the first protective layer 110. For
example, the protrusions 230b of the third adhesive member 230 may
have a adhesive interface with each of the first adhesive member
210 and the second adhesive member 220. The adhesive interface
between the protrusions 230b and the first adhesive member 210
and/or the adhesive interface between the protrusions 230b and the
second adhesive member 220 may be aligned in the third direction Z
with respect to an adhesive interface between the protrusions 230b
and the heat radiation member 410. The adhesive interface may refer
to a physical boundary, but may not be visible.
[0068] The third adhesive member 230 attached to the inner walls of
the first through fourth through holes 410h, 220h, 310h and 210h
and the first protective layer 110 can improve the durability of
the heat radiation sheet 1000. In addition, for example, even when
the heat radiation member 410 is made of a material that is
susceptible to damage in the third direction Z and is easily peeled
off, since the protrusions 230b of the third adhesive member 230
are coupled to the inner walls of the first through holes 410h
penetrating the heat radiation member 410, the internal adhesion
inside the heat radiation member 410 can be at least partially
improved, and excellent physical and mechanical properties can be
given to the heat radiation sheet 1000.
[0069] A heat radiation sheet according to embodiments described
with reference to FIGS. 1 and 2 and below can be cut into an
appropriate size and shape before being attached to a product. In
this case, the heat radiation sheet may be cut and placed such that
each planar quadrant of the cut heat radiation sheet partially
includes at least one through hole. This can further improve the
peeling property of the heat radiation sheet when the heat
radiation sheet is made into a product.
[0070] Other embodiments of the inventive concept will hereinafter
be described.
[0071] FIG. 3 is an exploded perspective view of a heat radiation
sheet 1001 according to an embodiment.
[0072] Referring to FIG. 3, the heat radiation sheet 1001 according
to the current embodiment is different from the heat radiation
sheet 1000 according to the embodiment of FIG. 1 in that first
through holes 411h of a heat radiation member 411, second through
holes 221h of a second adhesive member 221, third through holes
311h of a support member 311 and fourth through holes 211h of a
first adhesive member 211 are regularly arranged on a plane but are
separated from each other in a first direction X and a direction at
an acute angle to the first direction X. In addition, the planar
arrangement of protrusions 231b of a third adhesive member 231 may
correspond to that of the first through fourth through holes 411h,
221h, 311h and 211h.
[0073] FIG. 4 is a cross-sectional view of a heat radiation sheet
1002 according to an embodiment.
[0074] Referring to FIG. 4, the heat radiation sheet 1002 according
to the current embodiment is different from the heat radiation
sheet 1000 according to the embodiment of FIG. 1 in that a heat
radiation member 412, a second adhesive member 222, a support
member 312, and a first adhesive member 212 have one or more
continuous through holes H extending in a third direction (a
thickness direction), but an inner wall of each of the through
holes H at least partially includes an inclined portion 412s.
[0075] A first end (an upper end in the drawing) of each through
hole of the heat radiation member 412 facing a third adhesive
member 232 partially includes the inclined portion 412s. In FIG. 4,
the inclined portion 412s is a flat downwardly inclined surface. In
other embodiments, however, the inclined portion 412s may slope
downward in an upwardly or downwardly convex shape in the drawing
with a predetermined curvature. An inner wall of a second end (a
lower end in the drawing) of each through hole of the heat
radiation member 412 facing the second adhesive member 222 may be
substantially perpendicular.
[0076] In an exemplary embodiment, a planar area S.sub.1 of each
through hole of the heat radiation member 412 in a first surface
(an upper surface in the drawing) of the heat radiation member 412
facing the third adhesive member 232 may be greater than a planar
area S.sub.2 of each through hole of the heat radiation member 412
in a second surface (a lower surface in the drawing) of the heat
radiation member 412 facing the second adhesive member 222. That
is, the planar area of each through hole of the heat radiation
member 412 may be reduced from a second protective layer 120 toward
a first protective layer 110. This may make it easy to form
protrusions 232b of the third adhesive member 232 in the method of
manufacturing a heat radiation sheet which will be described
later.
[0077] The inner walls of the through holes of the second adhesive
member 222, the support member 312 and the first adhesive member
212 may be substantially perpendicular. That is, the planar areas
of the through holes of the second adhesive member 222, the support
member 312 and the first adhesive member 212 may be substantially
uniform regardless of position in the third direction (the
thickness direction). In other words, the planar area of each
through hole of the second adhesive member 222 in a first surface
of the second adhesive member 222 facing the heat radiation member
412 may be substantially equal to the planar area S.sub.2 of each
through hole 412h of the heat radiation member 412 facing the
second adhesive member 222.
[0078] In addition, a planar area of each through hole of the
second adhesive member 222 in the first surface (an upper surface
in the drawing) of the second adhesive member 222 facing the heat
radiation member 412 may be substantially equal to a planar area
S.sub.3 of each through hole of the first adhesive member 212 in a
second surface (a lower surface in the drawing) of the first
adhesive member 212 facing the first protective layer 110.
[0079] FIG. 5 is a cross-sectional view of a heat radiation sheet
1003 according to an embodiment.
[0080] Referring to FIG. 5, the heat radiation sheet 1003 according
to the current embodiment is different from the heat radiation
sheet 1002 according to the embodiment of FIG. 4 in that a heat
radiation member 413, a second adhesive member 223, a support
member 313, and a first adhesive member 213 have one or more
continuous through holes H extending in a third direction (a
thickness direction), but an inner wall of each of the through
holes H includes an inclined surface. In FIG. 5, the inclined
surface is a flat downwardly inclined surface. In other
embodiments, however, the inclined surface may slope downward in an
upwardly or downwardly convex shape in the drawing with a
predetermined curvature.
[0081] The inner wall of each of the continuous through holes H may
include a continuous inclined surface. That is, due to the inclined
surface of the inner wall of each of the through holes H, the
planar area of each of the through holes H may vary according to
position in the third direction (the thickness direction). For
example, the planar area of each through hole H may be reduced from
a second protective layer 120 toward a first protective layer 110.
In an exemplary embodiment, the planar area of each through hole in
a first surface (an upper surface in the drawing) of each of the
heat radiation member 413, the first adhesive member 213, the
second adhesive member 223 and the support member 313 may be
greater than that of each through hole in a second surface (a lower
surface in the drawing).
[0082] For example, a planar area S.sub.1 of each through hole of
the heat radiation member 413 in the first surface (the upper
surface in the drawing) of the heat radiation member 413 facing a
third adhesive member 233 may be greater than a planar area S.sub.2
of each through hole of the heat radiation member 413 in the second
surface (the lower surface in the drawing) of the heat radiation
member 413 facing the second adhesive member 223.
[0083] In addition, the planar area S.sub.2 of each through hole
413h of the heat radiation member 413 in the second surface of the
heat radiation member 413 facing the second adhesive member 223 may
be substantially equal to a planar area of each through hole of the
second adhesive member 223 in the first surface (the upper surface
in the drawing) of the second adhesive member 223 facing the heat
radiation member 413.
[0084] Furthermore, a planar area of each through hole of the
second adhesive member 223 in the first surface of the second
adhesive member 223 facing the heat radiation member 413 may be
greater than a planar area S.sub.3 of each through hole of the
first adhesive member 213 in the second surface (the lower surface
in the drawing) of the first adhesive member 213 facing the first
protective layer 110.
[0085] FIG. 6 is a cross-sectional view of a heat radiation sheet
1004 according to an embodiment.
[0086] Referring to FIG. 6, the heat radiation sheet 1004 according
to the current embodiment is different from the heat radiation
sheet 1000 according to the embodiment of FIG. 1 in that it further
includes a metal particle layer 510 disposed on a second surface (a
lower surface in the drawing) of a second protective layer 124
facing a third adhesive member 234.
[0087] In an exemplary embodiment, the surface roughness of the
second surface of the second protective layer 124 facing the third
adhesive member 234 may be substantially equal to the surface
roughness of a first surface (an upper surface in the drawing) of a
first protective layer 110 facing a first adhesive member 210.
[0088] The metal particle layer 510 may be attached to the second
surface of the second protective layer 124. In addition, the metal
particle layer 510 may protrude from the second surface of the
second protective layer 124 to form projections. The metal particle
layer 510 may be made of thermally conductive particles, copper
(Cu), cobalt (Co), nickel (Ni), iron (Fe), tin (Sn), zinc (Zn),
indium (In), tungsten (W), an alloy of the same, or metal particles
containing an oxide of the same. The surface roughness of an
attachment surface of the second protective layer 124 which is
attached using a composition for forming an adhesive member may
become relatively greater due to the projections formed by the
metal particle layer 510 disposed on the second surface of the
second protective layer 124.
[0089] A method of manufacturing a heat radiation sheet according
to the inventive concept will hereinafter be described.
[0090] FIGS. 7 through 13 are views illustrating a method of
manufacturing a heat radiation sheet according to an
embodiment.
[0091] Referring to FIG. 7, an adhesive member 630 including a
first release member 610, a first adhesive member 210' disposed on
the first release film 610, a support member 310' disposed on the
first adhesive member 210', a second adhesive member 220' disposed
on the support member 310', and a second release film 620 disposed
on the second adhesive member 220' is prepared. In an exemplary
embodiment, the adhesive member 630 may be a double-sided adhesive
member including the first adhesive member 210' and the second
adhesive member 220' made of thermosetting resin. The first
adhesive member 210', the support member 310' and the second
adhesive member 220' are the same as the first adhesive member 210,
the support member 310 and the second adhesive member 220 of FIG. 1
except that no through holes are formed in each of the first
adhesive member 210', the support member 310' and the second
adhesive member 220'. Therefore, a detailed description of the
first adhesive member 210', the support member 310' and the second
adhesive member 220' will be omitted.
[0092] Referring to FIGS. 7 and 8, the first and second release
films 610 and 620 are removed. Then, a carrier film 640 is placed
on a second surface (a lower surface in the drawings) of the first
adhesive member 210', and a heat radiation member 410' is placed on
a first surface (an upper surface in the drawings) of the second
adhesive member 220'. In an exemplary embodiment, the placing of
the carrier film 640 and the heat radiation member 410' may be
performed using a roll-to-roll process. The carrier film 640 may be
a polymer film such as polyethylene terephthalate. The heat
radiation member 410' is the same as the heat radiation member 410
of FIG. 1 except that no through holes are formed in the heat
radiation member 410'. Therefore, a detailed description of the
heat radiation member 410' will be omitted. In an embodiment, the
first release film 610 may not be removed and may be used together
with the carrier film.
[0093] Referring to FIGS. 7 through 9, one or more through holes H
are formed in each of the heat radiation member 410, the second
adhesive member 220, the support member 310, and the first adhesive
member 210. The forming of the through holes H may be an operation
of perforating the heat radiation member 410, the second adhesive
member 220, the support member 310 and the first adhesive member
210 using a mold 650 having a shape corresponding to the through
holes H. In an exemplary embodiment, grooves may be formed in at
least part of a first surface (an upper surface in the drawing) of
the carrier film 641.
[0094] In particular, even when the heat radiation member 410 has a
brittle characteristic and the first adhesive member 210 and the
second adhesive member 220 have flexible characteristics, it is
possible to easily form through holes having a uniform shape and
depth without increasing the overall thickness by placing the
relatively rigid support member 310 between the first adhesive
member 210 and the second adhesive member 220.
[0095] Referring to FIGS. 7 through 10, the carrier film 641 is
removed, and a first protective layer 110 is placed on the second
surface (the lower surface in the drawing) of the first adhesive
member 210. In an exemplary embodiment, the placing of the first
protective layer 110 may be performed using a roll-to-roll process.
Since the first protective layer 110 has been described above with
reference to FIG. 1, a detailed description of the first protective
layer 110 will be omitted.
[0096] Referring to FIGS. 7 through 11, a third adhesive member 230
is formed on the heat radiation member 410. The forming of the
third adhesive member 230 may be an operation of placing the third
adhesive member 230 to contact all of the first protective layer
110, the first adhesive member 210, the support member 310, the
second adhesive member 220 and the heat radiation member 410.
[0097] In an exemplary embodiment, the placing of the third
adhesive member 230 may include providing a composition 230' for
forming a third adhesive member on a first surface of the heat
radiation member 410, filling the through holes H formed in the
heat radiation member 410, the second adhesive member 220, the
support member 310 and the first adhesive member 210 with the
composition 230', and forming the third adhesive member 230, which
includes a base portion 230a contacting the first surface of the
heat radiation member 410 and protrusions 230b protruding from the
base portion 230a and inserted into the through holes H, by curing
the composition 230'.
[0098] The composition 230' for forming a third adhesive member may
be a photocurable resin composition having a shrinkage ratio of 5%
or less. Therefore, the volume of the composition 230' lost during
a curing process can be minimized, thereby enabling the protrusions
230b of the third adhesive member 230 to be fully inserted into the
through holes H and preventing a heat radiation sheet from being
warped or twisted after the curing process. The base portion 230a
of the third adhesive member 230 may contact and adhere to the
first surface (the upper surface in the drawings) of the heat
radiation member 410, and the protrusions 230b of the third
adhesive member 230 may be inserted into the through holes H to
contact and adhere to inner walls of the through holes H and a
first surface of the first protective layer 110. That is, the
protrusions 230b may contact all of the heat radiation member 410,
the second adhesive member 220, the support member 310, the first
adhesive member 210 and the first protective layer 110. Since the
third adhesive member 230 has been described above with reference
to FIG. 1, a detailed description of the third adhesive member 230
will be omitted.
[0099] Next, referring to FIGS. 7 through 12, a third release film
660 is placed on and pressed against a first surface (an upper
surface in the drawings) of the third adhesive member 230. In an
exemplary embodiment, the placing and pressing of the third release
film 660 may be performed using a roll-to-roll process.
[0100] The placing and pressing of the third release film 660 may
be an operation of increasing the adhesion between the first
protective layer 110, the first adhesive member 210, the support
member 310, the second adhesive member 220, the third adhesive
member 230 and the third release film 660 by pressing them.
Accordingly, the durability of a heat radiation sheet manufactured
can be improved. However, in some embodiments, the placing and
pressing of the third release film 660 may be omitted.
[0101] Referring to FIGS. 7 through 13, the first surface (the
upper surface in the drawings) of the third adhesive member 230 is
exposed by removing the third release film 660, and a second
protective layer 120 is placed on the first surface of the third
adhesive member 230. In an exemplary embodiment, the removing of
the third release film 660 and the placing of the second protective
layer 120 may be performed using a roll-to-roll process. A second
surface (a lower surface in the drawings) of the second protective
layer 120 facing the third adhesive member 230 may have a certain
surface roughness. The surface roughness of the second surface of
the second protective layer 120 may be formed using a chemical
method. For example, the surface roughness of the second surface of
the second protective layer 120 may be formed by etching the second
surface of the second protective layer 120 using an acid. When a
chemical method is used, a fine and uniform uneven surface can be
formed. Since the second protective layer 120 has been described
above with reference to FIG. 1, a detailed description of the
second protective layer 120 will be omitted.
[0102] The method of manufacturing a heat radiation sheet according
to the current embodiment is performed using a roll-to-roll
process. Therefore, the manufacturing process can be simplified,
and the manufacturing cost can be reduced. Also, since the
roll-to-roll process is used, a large-sized heat radiation sheet,
instead of a sheet of a unit size, can be manufactured and then cut
for use.
[0103] Hereinafter, the inventive concept will be described in more
detail by way of Example and Experimental Example.
Example
[0104] A heat radiation sheet was manufactured using a 9
.mu.m-thick copper thin film as first and second protective layers
and a 17 .mu.m-thick graphite film as a heat radiation member. Each
through hole of the heat radiation sheet had a diameter of 4 mm, a
horizontal distance between the through holes was 20 mm, and a
vertical distance between the through holes was 10 mm. FIG. 14 is a
planar photograph of the heat radiation sheet manufactured
according to Example and then cut into a size of 130 mm.times.25
mm.
Experimental Example: Peel Strength Test
[0105] After a lower protective layer (e.g., the first protective
layer of FIG. 1) of the heat radiation sheet manufactured according
to Example was removed, a lowermost adhesive layer (e.g., the first
adhesive member of FIG. 1) of the heat radiation sheet was attached
to a stainless steel substrate(SUS304). Then, at room temperature,
a horizontal end of the stainless steel substrate was pulled to one
side, and at the same time, a corresponding horizontal end of the
heat radiation sheet was pulled to the other side to peel off the
heat radiation sheet. In this way, a 180-degree peel strength test
was conducted, and the results are illustrated in FIG. 15. Here,
the peeling speed was 300 mm/min.
[0106] In FIG. 15, the horizontal axis indicates relative position
in the heat radiation sheet in a horizontal direction, and the
vertical axis indicates peel strength at each position in the heat
radiation sheet. Referring to FIG. 15, the peel strength is about
1500 gf/25 mm at a 10 mm position (corresponding to {circle around
(1)} in FIG. 14) and a 30 mm position (corresponding to {circle
around (3)} in FIG. 14) corresponding to through holes but is about
30 gf/25 mm at, e.g., a 20 mm position (corresponding to {circle
around (2)} in FIG. 14) at which no through holes are formed. This
may be because an adhesive member (e.g., the protrusions of the
third adhesive member of FIG. 1) inserted into the through holes
and extending in a thickness direction serves as a stopper in the
peeling process. That is, the adhesive member inserted into the
through holes penetrating the heat radiation member significantly
improves the peel strength of at least part of the heat radiation
sheet. In other words, the adhesive members (e.g., the first
through third adhesive members of FIG. 1) can suppress a peeling
defect of the heat radiation member in the thickness direction.
[0107] While the present invention has been particularly
illustrated and described with reference to exemplary embodiments
thereof, it will be understood by those of ordinary skill in the
art that various changes in form and detail may be made therein
without departing from the spirit and scope of the present
invention as defined by the following claims. The exemplary
embodiments should be considered in a descriptive sense only and
not for purposes of limitation.
* * * * *