Heat transfer member and electronic device

Abstract

A heat transfer member according to the present invention comprises a long substrate that extends in an X direction, wherein the substrate includes a graphite material, the thermal conductivity of which in the X direction is higher than the thermal conductivity thereof in a Y direction intersecting the X direction, and has a first connection part that is located on one side in the X direction and that is a region to which a heat generation component is connected and a second connection part that is located on the other side in the X direction and that is a region to which a cooling component is connected. Alternatively, the heat transfer member comprises a long substrate that extends in the X direction, wherein the substrate includes a graphite material, the thermal conductivity of which in a Z direction intersecting the X direction and the Y direction is higher than the thermal conductivity thereof in the Y direction intersecting the X direction, and has a first connection part that is located on one side in the Z direction and that is a region to which a heat generation component is connected and a second connection part that is located on the other side in the Z direction and that is a region to which a cooling component is connected.

Description

Heat transfer member and electronic device

[0001] The present disclosure relates to a heat transfer member and an electronic device.

[0002] Patent Document 1 describes a heat pipe that holds a working fluid inside as a heat transfer member.

[0003] JP 2018-009715 A

[0004] The heat transfer member according to the present disclosure includes an elongated substrate extending in an X direction, the substrate including a graphite material having a higher thermal conductivity in the X direction than in a Y direction intersecting the X direction, and the substrate having a first connection portion on one side in the X direction, which is an area to which a heat-generating component is connected, and a second connection portion on the other side in the X direction, which is an area to which a cooling component is connected.

[0005] Furthermore, a heat transfer member according to the present disclosure includes an elongated substrate extending in an X direction, the substrate including a graphite material having a higher thermal conductivity in a Z direction intersecting with the X and Y directions than in a Y direction intersecting with the X direction, the substrate having a first connection portion on one side in the Z direction which is an area to which a heat-generating component is connected, and a second connection portion on the other side in the Z direction which is an area to which a cooling component is connected.

[0006] The electronic device according to the present disclosure includes the heat transfer member described above; a heat-generating component connected to the first connection portion; and a cooling component connected to the second connection portion.

[0007] 1A ; FIG. 1B is a perspective view of a heat transfer member according to a first embodiment of the present disclosure; FIG. 1C is a perspective view of a heat transfer member according to the first embodiment of the present disclosure, showing a configuration with a protective film removed; FIG. 1D is a cross-sectional view taken along line A-A in FIG. 1A; FIG. 1E is a cross-sectional view taken along line B-B in FIG. 1A; FIG. 1F is a diagram illustrating properties of a graphite material; FIG. 1G is a cross-sectional view showing a third surface of a graphite material; FIG. 1H is a cross-sectional view showing a second surface of a graphite block; FIG. 1I is a perspective view of an electronic device incorporating a heat transfer member; FIG. 1J is a front view of an electronic device incorporating a heat transfer member; FIG. 1J is a front view of another example of use of the heat transfer member; FIG. 1J is a view showing another example of use of the heat transfer member, showing a plan view for explaining the relationship between the heat transfer member and a heat-generating component; FIG. 1I is a perspective view of an example of a heat transfer member according to a second embodiment of the present disclosure; FIG. 1J is a perspective view of an example of a heat transfer member according to the second embodiment of the present disclosure, showing a configuration with a protective film removed; FIG. 1J is a perspective view of another example of a heat transfer member according to the second embodiment of the present disclosure, showing a configuration with a protective film removed; FIG. 1I is a perspective view of a heat transfer member according to a third embodiment of the present disclosure. 1 is a perspective view showing a heat transfer member according to a third embodiment of the present disclosure, and is a perspective view showing a configuration with a protective film removed; FIG. 2 is a perspective view showing a check valve; FIG. 3 is an exploded perspective view showing a check valve; and FIG. 4 is a view illustrating an example of a method for manufacturing a heat transfer member according to the present disclosure.

[0008] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. Heat transfer members such as heat pipes are used while being disposed in the vicinity of electronic components. Therefore, there is a need for heat transfer members that do not leak liquid. An object of the present disclosure is to provide a heat transfer member and an electronic device that do not use liquid.

[0009] 1A and 1B are diagrams showing an example of a heat transfer member 100 according to a first embodiment of the present disclosure, where Fig. 1A is a perspective view of the heat transfer member 100 and Fig. 1B is a perspective view of a substrate 110 (a perspective view of a configuration excluding a protective film 120). Fig. 2A is a cross-sectional view taken along line A-A in Fig. 1A, and Fig. 2B is a cross-sectional view taken along line B-B in Fig. 1A. Fig. 3 is a diagram illustrating the properties of a graphite material 10.

[0010] The heat transfer member 100 of one embodiment has high thermal conductivity and can quickly transfer heat received at one end 101 to the other end 102. The heat transfer member 100 may include an elongated substrate 110 extending in the X direction. The substrate 110 may have a first surface 111 intersecting the X direction, a second surface 112 located on the opposite side of the first surface 111, and a side surface 113 located between the first surface 111 and the second surface 112 and extending along the X direction. The heat transfer member 100 may further include a protective film 120 covering the first surface 111, the second surface 112, and the side surface 113.

[0011] <<Substrate>> The dimension of the substrate 110 in the X direction may be longer than the dimension in the Y direction that intersects (e.g., is perpendicular to) the X direction. The dimension of the substrate 110 in the X direction may also be longer than the dimension in the Z direction that intersects (e.g., is perpendicular to) the X and Y directions. "Elongated shape extending in the X direction", i.e., "elongated in the X direction", may mean that the dimension in the X direction is longer than the dimension in a direction that intersects (e.g., is perpendicular to) the X direction.

[0012] The substrate 110 may include a quadrangular prism-shaped graphite material 10. The graphite material 10 may have a structure in which a plurality of graphenes are stacked in a first direction A1. The graphene may be a sheet-like substance in which a honeycomb structure formed by bonding carbon atoms spreads in a two-dimensional direction. Adjacent graphenes may be bonded to each other by intermolecular forces, which are van der Waals forces.

[0013] The surface of graphite material 10 may have a surface where graphene spreads in a two-dimensional direction and a surface where multiple graphene layers appear. Hereinafter, the surface where graphene spreads in a two-dimensional direction will be referred to as a "crystal surface," and the surface where graphene layers appear will be referred to as a "crystal layer surface." In addition, in the drawings, the "crystal surface" will be represented by a honeycomb pattern, and the "crystal layer surface" will be represented by a striped pattern.

[0014] A first direction A1 in graphite material 10, i.e., the stacking direction of graphene, may be parallel to the Y direction. A second direction A2 in graphite material 10, i.e., one of the two-dimensional directions in which graphene extends, may be parallel to the X direction. A third direction A3 in graphite material 10, i.e., the other of the two-dimensional directions in which graphene extends, may be parallel to the Z direction.

[0015] Graphite material 10 may have anisotropy in its brittleness. As an example of the anisotropy in its brittleness, graphite material 10 may have a tendency to cleave easily along a plane in which graphene extends, i.e., a plane intersecting with first direction A1, as shown in FIG. 3 . Cleavage means breaking along a certain plane. FIG. 3 shows a state in which crack E1 has occurred due to cleavage.

[0016] Furthermore, as anisotropy of the brittleness, graphite material 10 may have a property that when stress is generated along the plane direction of the crystal plane, graphene located on the crystal plane is easily peeled off. Furthermore, graphite material 10 may have a property that edge portion E2 (see FIGS. 4 and 5 ) of the graphene is weak and easily breaks from edge portion E2.

[0017] As a specific material, the graphite material 10 may be mainly composed of pyrolytic graphite. "Mainly composed" may mean a volume ratio of 80% or more. Pyrolytic graphite may be produced as follows: First, a resin material such as polyimide is carbonized and decomposed into hydrocarbon gas. Next, the decomposed hydrocarbon is vapor-deposited and laminated. Then, a pressure annealing treatment is performed to produce pyrolytic graphite. In one embodiment, the substrate 110 may be a single component, i.e., a component including only the graphite material 10.

[0018] <Each Surface of Graphite Material> Figure 4 is a cross-sectional view showing third surface 13 of graphite material 10. Figure 5 is a cross-sectional view showing second surface 12 of graphite material 10. Figure 4 shows part C1 of Figure 3, and Figure 5 shows part C2 of Figure 3. Graphite material 10 may be in the shape of a rectangular parallelepiped, with two surfaces opposite to each other being crystal planes and the remaining four surfaces being crystal layer planes.

[0019] The surfaces of the graphite material 10 may include a pair of first surfaces 11 extending along a first direction A1 and a second direction A2 that intersect (e.g., perpendicular to) each other, a pair of second surfaces 12 extending along the first direction A1 and a third direction A3 that intersect (e.g., perpendicular to) each other, and a pair of third surfaces 13 extending along the second direction A2 and the third direction A3 that intersect (e.g., perpendicular to) each other. In the graphite material 10, the two third surfaces 13 located opposite each other may be crystal planes, and the two first surfaces 11 located opposite each other and the two second surfaces 12 located opposite each other may be crystal layer planes. In other words, the side surfaces of the graphite material 10 may include the third surfaces 13 that are crystal planes and the second surfaces 12 that are crystal layer planes.

[0020] Third surface 13, which is a crystal plane, may be a plane extending in two directions intersecting first direction A1. The two directions may be second direction A2 and third direction A3, which are perpendicular to first direction A1 and perpendicular to each other. Second surface 12, which is a crystal layer plane, may be a plane extending in first direction A1 and third direction A3. As shown in FIG. 4 , third surface 13 is a crystal plane where graphene peeling is likely to occur, and edge portions E2 of graphene that are prone to breakage may appear. As shown in FIG. 5 , second surface 12 has edge portions E2 of graphene that are prone to breakage. Similarly, first surface 11 also has edge portions E2 of graphene that are prone to breakage. Covering the surface of graphite material 10 with protective film 120 reduces the occurrence of peeling or breakage, thereby improving the toughness of heat transfer member 100.

[0021] <Thermal Conductivity of Graphite Material> The graphite material 10 may have very high thermal conductivity in directions along the crystal planes. The thermal conductivity of the graphite material 10 in the second direction A2 and the third direction A3 may be 200 W / m·K or more, while the thermal conductivity in the first direction A1 may be lower than the thermal conductivity in the second direction A2 or the third direction A3, such as 7 W / m·K. That is, the graphite material 10 may have anisotropic thermal conduction. The thermal conductivity in the second direction A2 and the third direction A3 may be preferably 370 W / m·K or more, more preferably 450 W / m·K or more, and even more preferably 800 W / m·K or more. In one embodiment, the thermal conductivity of the graphite material 10 in the second direction A2 and the third direction A3 may be 1200 W / m·K or more, more specifically, approximately 1700 W / m·K.

[0022] <Surface Roughness of Graphite Material> As shown in FIG. 4 , in graphite material 10, the surface roughness of third surface 13, which is a crystal plane, may be smaller than the surface roughness of first surface 11, which is a crystal layer plane. Specifically, the surface roughness of first surface 11 may be 20 times or more, 10 times or more but less than 20 times, or 5 times or more but less than 10 times the surface roughness of third surface 13. The surface roughness refers to the arithmetic mean roughness Ra defined in JIS (Japanese Industrial Standards) B_0601:2001. According to this configuration, as shown in FIG. 4 , the number of graphene edge portions E2 appearing on third surface 13 is reduced. Therefore, the brittleness of third surface 13 can be reduced.

[0023] 4 and 5 , in graphite material 10, the surface roughness of second surface 12, which is a crystal layer surface, may be greater than the surface roughness of third surface 13, which is a crystal surface. Specifically, the surface roughness of second surface 12 may be 20 times or more, 10 times or more but less than 20 times, or 5 times or more but less than 10 times the surface roughness of third surface 13. The surface roughness refers to the arithmetic mean roughness Ra described above.

[0024] As shown in FIG. 5 , second surface 12 includes relatively large irregularities due to the surface roughness. The irregularities may be fine irregularities. On second surface 12, a portion of protective film 120 is located within a recess F1 of the irregularities of second surface 12. Therefore, an anchor effect is produced, improving the adhesion of protective film 120 to second surface 12. Like second surface 12, first surface 11 is a crystalline layer surface, and therefore an anchor effect is produced, improving the adhesion of protective film 120 to first surface 11. This prevents protective film 120 from peeling off from substrate 110. Furthermore, since protective film 120 is located within the recess F1 of the irregularities, the thermal resistance between protective film 120 and graphite material 10 can be reduced compared to a configuration in which a gap is formed in recess F1.

[0025] <Thermal Expansion Characteristics of Graphite Material> The linear expansion coefficient of the graphite material 10 may be highly anisotropic at the first surface 11 and the second surface 12. Specifically, the linear expansion coefficient of the graphite material 10 may be 20 [10^-6 / K] or more in the first direction A1 and 0.050 [10^-6 / K] or less in the second direction A2 and the third direction A3. Furthermore, the linear expansion coefficient of the graphite material 10 may be 24 [10^-6 / K] or more in the first direction A1. Furthermore, the linear expansion coefficient of the graphite material 10 may be a value in the range of 27 [10^-6 / K] or less in the first direction A1. Furthermore, the linear expansion coefficient of the graphite material 10 in the second direction A2 and the third direction A3 may be a negative value, specifically, may be −0.001 [10^-6 / K] or less. The linear expansion coefficient of the graphite material 10 in the second direction A2 and the third direction A3 may be −0.01 [10 −6 / K] or more.

[0026] Protective Film The protective film 120 may be a metal film, a ceramic film, or a resin film. The protective film 120 may be formed by thermal spraying or plating. When the protective film 120 is formed by thermal spraying, the surface of the substrate 110 may be covered with a base film (e.g., a titanium film) having a thickness of 1 μm or more, and then a metal film such as aluminum or stainless steel (SUS), or a ceramic film such as alumina, may be formed by thermal spraying as the protective film 120. When the protective film 120 is formed by plating, the surface of the substrate 110 may be covered with a base film (e.g., a nickel film) having a thickness of 1 μm or more, and then a metal film such as copper or gold may be formed by plating as the protective film 120. The protective film 120 may include a base film.

[0027] By employing a metal film, it is possible to realize the protective film 120 with high thermal conductivity, which contributes to the efficient heat transfer performance of the heat transfer member 100. Furthermore, when the heat transfer member 100 is required to have electrical conductivity, this requirement can be met. By employing a ceramic film or a resin film, when the heat transfer member 100 is required to have electrical insulation, this requirement can be met.

[0028] The thermal conductivity of the protective film 120 may be highly isotropic compared to that of the graphite material 10. The thermal conductivity of the protective film 120 may be higher than the thermal conductivity of the graphite material 10 in the first direction A1. This configuration provides an effect of dispersing heat in the first direction A1 via the protective film 120 at the first surface 11 and the second surface 12. Therefore, the addition of this dispersion effect allows the heat transfer member 100 to achieve more efficient heat transfer performance.

[0029] The surfaces of the substrate 110 may include one first surface 111, one second surface 112, and four side surfaces 113. Of the pair of second surfaces 12 of the graphite material 10, one second surface 12 may correspond to the first surface 111 of the substrate 110, and the other second surface 12 may correspond to the second surface 112 of the substrate 110. Furthermore, the pair of first surfaces 11 and the pair of third surfaces 13 of the graphite material 10 may correspond to the side surfaces 113 of the substrate 110.

[0030] The entire surface of the substrate 110 may be covered with the protective film 120. This configuration can prevent the protective film 120 from peeling off. Peeling is more likely to occur at the edges of the protective film 120 than at other parts. Therefore, by covering the entire surface of the substrate 110 with the protective film 120 and reducing (e.g., eliminating) the edges of the protective film 120, peeling of the protective film 120 can be prevented. Furthermore, by covering the entire surface of the substrate 110 with the protective film 120, the complexity of the process of forming the protective film 120 can be reduced.

[0031] The protective film 120 covering a portion of the surface of the base material 110 and the protective film 120 covering the remaining portion may be made of the same material or different materials. Specifically, a metal film may be used as the protective film 120 covering the entire surface of the base material 110. Alternatively, a metal film may be used as the protective film 120 covering a portion of the surface of the base material 110, and a ceramic film or a resin film may be used as the protective film 120 covering the remaining portion.

[0032] 6A and 6B are diagrams showing an example of an electronic device 300 incorporating the heat transfer member 100, where Fig. 6A is a perspective view and Fig. 6B is a front view. The heat transfer member 100 may be replaced with the heat transfer members 100A, 100B, and 100C of the second and third embodiments described below.

[0033] The electronic device 300 may include a heat transfer member 100, a heat-generating component 310 thermally connected to a first connecting portion 160 of the heat transfer member 100, and a cooling component 320 thermally connected to a second connecting portion 170 of the heat transfer member 100. In Fig. 6B, for convenience, the cooling component 320 is indicated by a dashed line, the first connecting portion 160 is indicated by a thick dashed line, and the second connecting portion 170 is hatched.

[0034] The first connecting portion 160 may be provided on one side of the heat transfer member 100 in the X direction (e.g., the side of the one end 101). The first connecting portion 160 may be a region of the base material 110 to which a heat-generating component 310 such as an electronic element is connected. Furthermore, when the heat transfer member 100 includes a protective film 120, the first connecting portion 160 may be connected to the heat-generating component 310 such as an electronic element via the protective film 120. The second connecting portion 170 may be provided on the other side of the first connecting portion 160 in the X direction (e.g., the side of the other end 102). The second connecting portion 170 may be a region of the base material 110 to which a cooling component 320 such as a cooling fin is connected. Furthermore, when the heat transfer member 100 includes a protective film 120, the second connecting portion 170 may be connected to the cooling component 320 such as a cooling fin via the protective film 120. Here, "connected" may include a state of contact.

[0035] The protective film 120 covering the first connecting portion 160 may be made of a material with high thermal conductivity, such as a metal film. With this configuration, even when the heat-generating component 310 contacts the heat-transfer member 100 via the protective film 120, heat can be quickly conducted to the base material 110 via the protective film 120. The protective film 120 covering the second connecting portion 170 may be made of a material with high thermal conductivity, such as a metal film. With this configuration, even when the cooling component 320 contacts the heat-transfer member 100 via the protective film 120, heat can be quickly conducted to the cooling component 320 via the protective film 120.

[0036] That is, the protective film 120 (first protective film) that protects the first connecting portion 160 and the second connecting portion 170 may be a metal film. Furthermore, the protective film 120 (second protective film) that protects the region other than the first connecting portion 160 and the second connecting portion 170 may be a ceramic film or a resin film. Because the first connecting portion 160 and the second connecting portion 170 contact the heat-generating component 310 and the cooling component 320, respectively, the protective film 120 (first protective film) that covers the first connecting portion 160 and the second connecting portion 170 is not exposed within the electronic device 300.

[0037] On the other hand, the region of the base material 110 other than the first connecting portion 160 and the second connecting portion 170 does not come into contact with the heat-generating component 310 or the cooling component 320. Therefore, the protective film 120 (second protective film) covering the region other than the first connecting portion 160 and the second connecting portion 170 is exposed within the electronic device 300 and may come into contact with other electronic components. Therefore, even in a usage state where electrical insulation between the heat transfer member 100 and other electronic components is required, by employing a ceramic film or a resin film as the protective film 120 (second protective film) covering the region other than the first connecting portion 160 and the second connecting portion 170, it is possible to avoid problems such as malfunction of other electronic components even if the region comes into contact with the other electronic components.

[0038] The heat transfer member 100 may have one first connecting portion 160 as shown in FIGS. 6A and 6B , or may have multiple first connecting portions 160. When the heat transfer member 100 has multiple first connecting portions 160, all of the multiple first connecting portions 160 may be located on one side in the X direction (e.g., on the one end 101 side) of the second connecting portion 170. The heat transfer member 100 may have one second connecting portion 170 as shown in FIGS. 6A and 6B , or may have multiple second connecting portions 170. When the heat transfer member 100 has multiple second connecting portions 170, all of the multiple second connecting portions 170 may be located on the other side in the X direction (e.g., on the other end 102 side) of the first connecting portion 160.

[0039] The electronic device 300 may include a fan 330 that ventilates the inside of the electronic device 300. The electronic device 300 may include a heat transfer plate 340 located between the heat-generating component 310 and the heat transfer member 100. The heat transfer plate 340 may be made of a metal material such as copper or aluminum. With this configuration, heat from the heat-generating component 310 can be quickly conducted to the heat transfer member 100 via the heat transfer plate 340. Note that the heat transfer member 100 may be in direct contact with the heat-generating component 310.

[0040] In the electronic device 300, heat from the heat-generating component 310 is first transferred to the first connecting portion 160 of the heat-transfer member 100 via the heat-transfer plate 340. The heat transferred to the first connecting portion 160 is transferred to the second connecting portion 170 of the heat-transfer member 100 via the base material 110 of the heat-transfer member 100 (specifically, the portion of the base material 110 between the first connecting portion 160 and the second connecting portion 170). The heat transferred to the second connecting portion 170 is then transferred to the cooling component 320 in contact with the second connecting portion 170 and is released from the cooling component 320.

[0041] 7A and 7B are diagrams illustrating another example of use of the heat transfer member 100, where FIG. 7A is a front view and FIG. 7B is a plan view illustrating the relationship between the heat transfer member 100 and a heat-generating component 410. The heat transfer member 100 may replace the heat transfer members 100A and 100B of the second embodiment described below. As described above, the thermal conductivity of the graphite material 10 in the first direction A1 may be lower than the thermal conductivity in the second direction A2 or the third direction A3. That is, the thermal conductivity of the heat transfer member 100 in the Y direction may be lower than the thermal conductivity in the X direction or the Z direction. Therefore, the heat transfer member 100 may be a member that can quickly transfer heat received at one side in the X direction (e.g., the one end 101 side) to the other side in the X direction (e.g., the other end 102 side). Alternatively, the heat transfer member 100 may be a member that can quickly transfer heat received at one side in the Z direction (e.g., the bottom surface) to the other side in the Z direction (e.g., the top surface).

[0042] 6A and 6B is a device that utilizes the ability of the heat-transfer member 100 to quickly transfer heat received on one side in the X direction to the other side in the X direction, while the electronic device 400 shown in Figures 7A and 7B is a device that utilizes the ability of the heat-transfer member 100 to quickly transfer heat received on one side in the Z direction to the other side in the Z direction.

[0043] 7A and 7B may include a heat-transfer member 100, a heat-generating component 410 thermally connected to a first connecting portion 180 of the heat-transfer member 100, and a cooling component 420 thermally connected to a second connecting portion 190 of the heat-transfer member 100. In FIG. 7A , for convenience, the first connecting portion 180 is indicated by a thick dashed line, and the second connecting portion 190 is indicated by a thick line. The electronic device 400 may include a plurality of heat-generating components 410. That is, the heat-transfer member 100 may have a plurality of first connecting portions 180.

[0044] The first connecting portion 180 may be provided on one side (e.g., the lower surface) of the heat transfer member 100 in the Z direction. The first connecting portion 180 may be a region of the base material 110 to which a heat-generating component 410 such as an electronic element is connected (in contact). Furthermore, when the heat transfer member 100 includes a protective film 120, the first connecting portion 180 may be connected (in contact) with the heat-generating component 410 such as an electronic element via the protective film 120. The second connecting portion 190 may be provided on the other side of the first connecting portion 180 in the Z direction (e.g., the upper surface of the heat transfer member 100). The second connecting portion 190 may be a region of the base material 110 to which a cooling component 420 is connected (in contact). Furthermore, when the heat transfer member 100 includes a protective film 120, the second connecting portion 190 may be connected (in contact) with the cooling component 420 via the protective film 120.

[0045] The protective film 120 covering the first connecting portion 180 may be made of a material with high thermal conductivity, such as a metal film. With this configuration, even when the heat-generating component 410 contacts the heat-transfer member 100 via the protective film 120, heat can be quickly conducted to the base material 110 via the protective film 120. The protective film 120 covering the second connecting portion 190 may be made of a material with high thermal conductivity, such as a metal film. With this configuration, even when the cooling component 420 contacts the heat-transfer member 100 via the protective film 120, heat can be quickly conducted to the cooling component 420 via the protective film 120.

[0046] That is, the protective film 120 (first protective film) that protects the first connecting portion 180 and the second connecting portion 190 may be a metal film. Furthermore, the protective film 120 (second protective film) that protects an area other than the first connecting portion 180 and the second connecting portion 190 may be a ceramic film or a resin film. With this configuration, even in a usage state that requires electrical insulation between the heat transfer member 100 and other electronic components, even if the heat transfer member 100 comes into contact with other electronic components within the electronic device 400, problems such as malfunction of the other electronic components can be avoided.

[0047] The heat transfer member 100 may have one first connecting portion 180, or may have multiple first connecting portions 180 as shown in FIGS. 7A and 7B . When the heat transfer member 100 has multiple first connecting portions 180, all of the multiple first connecting portions 180 may be located on one side (e.g., the lower surface side) of the second connecting portion 190 in the Z direction. The heat transfer member 100 may have one second connecting portion 190 as shown in FIGS. 7A and 7B , or may have multiple second connecting portions 190. When the heat transfer member 100 has multiple second connecting portions 190, all of the multiple second connecting portions 190 may be located on the other side (e.g., the upper surface side) of the first connecting portion 180 in the Z direction.

[0048] The electronic device 400 may include a first heat transfer plate 430 located between the heat-generating component 410 and the heat transfer member 100. The first heat transfer plate 430 may be made of a metal material such as copper or aluminum. This configuration allows heat from the heat-generating component 410 to be quickly conducted to the heat transfer member 100 via the first heat transfer plate 430. Furthermore, this configuration allows, when heat is applied to a portion of the first heat transfer plate 430, the heat to be isotropically dispersed by the first heat transfer plate 430 and then conducted to the heat transfer member 100. Note that the heat transfer member 100 may be in direct contact with the heat-generating component 410 (without going through the first heat transfer plate 430).

[0049] The heat-generating component 410 may be connected to the first connecting portion 180 via a bonding material 440. The bonding material 440 may be solder. This configuration can reduce the inhibition of heat conduction caused by the bonding material 440. The bonding material 440 may be a thermally conductive adhesive, a thermally conductive filler (such as grease), or the like. The bonding material 440 may also be a silicone-based adhesive. This configuration can ensure insulation between the heat-generating component 410, such as an electronic element, and the heat-transfer member 100. The heat-generating component 410, such as an electronic element, may be mounted on a printed circuit board 450. The printed circuit board 450 may be screwed to a housing 460, such as a metal housing. The cooling component 420 may be connected to the second connecting portion 190 via a bonding material 470. The bonding material 470 may be solder. This configuration can reduce the inhibition of heat conduction caused by the bonding material 470. The bonding material 470 may be a thermally conductive adhesive, a thermally conductive filler (such as grease), etc. The bonding material 470 may be the same as the bonding material 440 or may be different from the bonding material 440.

[0050] The electronic device 400 may include a second heat transfer plate 480 located between the cooling component 420 and the heat transfer member 100. The second heat transfer plate 480 may be made of a metal material such as copper or aluminum. With this configuration, heat from the heat transfer member 100 can be quickly conducted to the cooling component 420 via the second heat transfer plate 480. Note that the heat transfer member 100 may be in direct contact with the cooling component 420 (without the second heat transfer plate 480).

[0051] In the electronic device 400, heat from the heat-generating component 410 is first transferred to the first connecting portion 180 of the heat-transfer member 100 via the first heat-transfer plate 430. The heat transferred to the first connecting portion 180 is transferred to the second connecting portion 190 of the heat-transfer member 100 via the base material 110 of the heat-transfer member 100 (specifically, a portion of the base material 110 between the first connecting portion 180 and the second connecting portion 190). The heat transferred to the second connecting portion 190 is then transferred via the second heat-transfer plate 480 to the cooling component 420 in contact with the second connecting portion 190, and is released from the cooling component 420. The electronic device 400 may include a heat-transfer material, such as a heat-transfer sheet, positioned between the cooling component 420 and the second heat-transfer plate 480. That is, the heat-transfer member 100 may be in contact with the cooling component 420 via the second heat-transfer plate 480 and the heat-transfer material. The heat transfer member 100 may be in contact with the heat transfer material without the second heat transfer plate 480. When the electronic device 400 includes a heat transfer sheet as the heat transfer material, the bonding material 470 may be omitted.

[0052] The cooling of the electronic device 300 does not have to be forced air cooling using the fan 330, but can be natural air cooling, for example. The cooling of the electronic device 400 does not have to be housing cooling, but can be forced cooling using, for example, a Peltier element. Furthermore, various heat sources (heat-generating components 310, 410) can be used, such as electronic elements such as semiconductor elements, heat dissipation components, heaters, and so on. Thus, the heat transfer member 100 can be used as a substitute for a heat pipe. Unlike heat pipes, the heat transfer member 100 does not use a liquid. Therefore, it has many advantages over heat pipes, such as no liquid leakage and greater flexibility in placement due to heat transport regardless of vertical or horizontal direction. Furthermore, unlike heat pipes, the heat transfer member 100 does not use a liquid, so it can suppress a decrease in cooling effectiveness due to inertial forces. Furthermore, the heat transfer member 100 is lighter than heat pipes that use a liquid (working fluid), making it suitable for installation on airplanes, rockets, electric vehicles, and so on.

[0053] [Embodiment 2] Figures 8A and 8B are diagrams illustrating an example of a heat transfer member 100A according to Embodiment 2 of the present disclosure, where Figure 8A is a perspective view of the heat transfer member 100A and Figure 8B is a perspective view of the substrate 110A (a perspective view of the configuration excluding the protective film 120). Figures 9A and 9B are diagrams illustrating an example of a heat transfer member 100B according to Embodiment 2 of the present disclosure, where Figure 9A is a perspective view of the heat transfer member 100B and Figure 9B is a perspective view of the substrate 110B (a perspective view of the configuration excluding the protective film 120). The heat transfer members 100A and 100B of Embodiment 2 differ from those of Embodiment 1 in the configuration of the substrates 110A and 110B (specifically, the shape of the graphite material 10), but may otherwise be similar to those of Embodiment 1. The differences are described in detail below.

[0054] As shown in FIGS. 8A and 8B , the heat transfer member 100A may include an elongated substrate 110A extending in the X direction. The substrate 110A may include a cylindrical graphite material 10 instead of the rectangular columnar graphite material 10. As shown in FIGS. 9A and 9B , the heat transfer member 100B may include an elongated substrate 110B extending in the X direction. The substrate 110B may include a polygonal columnar graphite material 10 other than the rectangular columnar graphite material 10 instead of the rectangular columnar graphite material 10. The substrate 110B shown in FIG. 9B includes an octagonal columnar graphite material 10. In one embodiment, the substrates 110A and 110B may be of a single structure, i.e., may include only the graphite material 10.

[0055] As described above, as long as the base materials 110, 110A, and 110B are columnar (rod-shaped) with the X direction intersecting (for example, perpendicular to) the bottom surface, the shape of the bottom surface (first surface 111 and second surface 112) may be changed as appropriate. That is, the heat transfer members 100, 100A, and 100B may be columnar (rod-shaped) members with the X direction intersecting (for example, perpendicular to) the bottom surface.

[0056] 10A and 10B are diagrams showing an example of a heat transfer member 100C according to a third embodiment of the present disclosure, with Fig. 10A being a perspective view of the heat transfer member 100C and Fig. 10B being a perspective view of a substrate 110C (a perspective view of the configuration excluding the protective film 120). The heat transfer member 100C of the third embodiment differs from the first and second embodiments in the configuration of the substrate 110C (specifically, in that it includes a backflow heat prevention structure 20), but the other configurations may be the same as those of the first and second embodiments. The differences will be described in detail below.

[0057] The heat transfer member 100C may include an elongated substrate 110C extending in the X direction. The substrate 110C may include a plurality of graphite materials 10C and backflow heat prevention structures 20 positioned between the graphite materials 10C. The substrate 110C may include a plurality of (e.g., two) backflow heat prevention structures 20.

[0058] The plurality of graphite materials 10C may be arranged in parallel in the X direction, with one of the second direction A2 and the third direction A3 (e.g., the second direction A2), which has high thermal conductivity, being parallel to the X direction. Of the plurality of graphite materials 10C, the graphite material 10C adjacent to the backflow heat prevention structure 20 at the other end 102 side may have, in the second surface 12 at the other end 102 side, a groove 16 extending along one of two directions intersecting the second direction A2 (e.g., the third direction A3).

[0059] 11A and 11B are diagrams showing an example of a backflow heat prevention structure 20, with FIG. 11A being a perspective view of the backflow heat prevention structure 20 and FIG. 11B being an exploded perspective view of the backflow heat prevention structure 20. The backflow heat prevention structure 20 is a member for preventing backflow of heat in a heat transfer member 100C. Like the heat transfer members 100, 100A, and 100B, the heat transfer member 100C is a member that can quickly transfer heat received at one end 101 to the other end 102. Therefore, backflow of heat refers to the movement of heat from the other end 102 side to the one end 101 side. The backflow heat prevention structure 20 may include a first member 21 that stores heat from the adjacent graphite material 10C on the one end 101 side and a second member 22 that prevents heat from returning to the adjacent graphite material 10C on the one end 101 side.

[0060] The first member 21 may be made of a metal material, such as copper or aluminum, that has a larger heat capacity than the graphite material 10C. With this configuration, it is possible to efficiently store heat from the adjacent graphite material 10C on the one end 101 side. The first member 21 may have a protrusion 212 that fits into the groove 16 of the adjacent graphite material 10C on the one end 101 side. With this configuration, it is possible to efficiently guide the heat from the adjacent graphite material 10C on the one end 101 side to the main body 211 of the first member 21.

[0061] The first member 21 may have a groove 213 extending along one of two directions intersecting with the X direction (e.g., the Z direction) on the surface of the main body 211 on the one end 101 side. A plurality of grooves 213 (e.g., two) may be provided. Furthermore, the protrusion 212 may protrude from between the grooves 213. The groove 213 may be defined by a groove wall surface formed from the one end 101 side toward the other end 102 side. The groove wall surface may include an inclined surface 214 inclined with respect to two directions intersecting with the extension direction of the groove 213 (e.g., the X direction and the Y direction). That is, the groove 213 may have a triangular shape in a plan view.

[0062] The second member 22 may have a structure similar to that of the graphite material 10, 10C. That is, the second member 22 may have a structure in which a plurality of graphenes are stacked in the first direction A1c. In other words, the thermal conductivity of the second member 22 in the first direction A1c may be lower than the thermal conductivity in the second direction A2c or the third direction A3c. The surface of the second member 22 may include a first surface 11 (crystal layer plane) having high thermal conductivity and intersecting with the third direction A3c, a second surface 12C (crystal layer plane) having high thermal conductivity and intersecting with the second direction A2c, and a third surface 13 (crystal plane) having low thermal conductivity and intersecting with the first direction A1c.

[0063] The second member 22 may be shaped to fit into the groove 213 of the first member 21. When the second member 22 is fitted into the groove 213, the third surface 13 (crystal plane) of the second member 22 may be in contact with the first member 21. This configuration can efficiently suppress heat from returning to the adjacent graphite material 10C on the one end 101 side. Due to the anisotropy of heat conduction described above, heat transfer from the first member 21 to the second member 22 via the third surface 13 is less likely to occur than heat transfer in a direction along the crystal plane. Therefore, a configuration in which the third surface 13 is in contact with the first member 21 can suppress heat transfer from the first member 21 to the second member 22 compared to a configuration in which only surfaces other than the third surface 13 (the first surface 11 and the second surface 12C) are in contact with the first member 21. As a result, it is possible to efficiently suppress heat from returning to the adjacent graphite material 10C on the one end 101 side.

[0064] Furthermore, third surface 13 of second member 22 may be in contact with inclined surface 214 of first member 21. That is, when second member 22 is in contact with first member 21 on a plurality of surfaces, the surface with the largest area among these surfaces may be third surface 13. With this configuration, it is possible to more efficiently suppress heat from returning to adjacent graphite material 10C on the one end 101 side.

[0065] The surface of the second member 22 may include two second surfaces 12C. Furthermore, one of the two second surfaces 12C may be in contact with the adjacent graphite material 10C on the one end 101 side, and the other second surface 12C may be in contact with the first member 21. With this configuration, heat transfers from the adjacent graphite material 10C on the one end 101 side to the first member 21 via the second member 22, i.e., along the second direction A2c in which thermal conductivity is high, so that heat from the adjacent graphite material 10C on the one end 101 side can be efficiently guided to the first member 21. Furthermore, the second surface 12C in contact with the first member 21 may be in contact with a heat conduction path from the protrusion 212 to the main body 211. This configuration allows heat to be concentrated in the heat conduction path from the protrusion 212 to the main body 211, so that the heat of the adjacent graphite material 10C on the one end 101 side can be efficiently guided to the main body 211.

[0066] The bonding material bonding the first member 21 and the second member 22 may be a brazing material or solder. This configuration reduces the inhibition of heat conduction caused by the bonding material. Furthermore, when a brazing material or solder is used as the bonding material, the thickness can be thinner than when, for example, a resin bonding material is used. The bonding material bonding the first member 21 and the second member 22 may be a thermally conductive adhesive, a thermally conductive filler (grease, etc.), etc. Furthermore, the bonding material bonding the graphite material 10C and the backflow heat prevention structure 20 may be a brazing material or solder. This configuration reduces the inhibition of heat conduction caused by the bonding material. The bonding material bonding the graphite material 10C and the backflow heat prevention structure 20 may be a thermally conductive adhesive, a thermally conductive filler (grease, etc.), etc.

[0067] In the heat transfer member 100C, when heat is transferred from one end 101 to the other end 102, the heat is transferred from the graphite material 10C located closest to the one end 101 to the backflow heat prevention structure 20 adjacent to that graphite material 10C, and accumulates in the first member 21 of that backflow heat prevention structure 20. The heat accumulated in that backflow heat prevention structure 20 is absorbed by the next graphite material 10C, transferred to the next backflow heat prevention structure 20, and accumulates in the first member 21 of that next backflow heat prevention structure 20. The heat accumulated in that next backflow heat prevention structure 20 is then absorbed by the graphite material 10C located closest to the other end 102, and released from that graphite material 10C.

[0068] Therefore, when heat transfer member 100C is incorporated into electronic device 300, first connecting portion 160 may be set so that graphite material 10C located closest to one end 101 is thermally connected to heat-generating component 310. Also, second connecting portion 170 may be set so that graphite material 10C located closest to the other end 102 is thermally connected to cooling component 320.

[0069] In one embodiment, the base material 110C has a rectangular prism shape, but is not limited thereto. As with the base materials 110, 110A, and 110B, the base material 110C may have a columnar (rod-like) shape with the X direction intersecting (e.g., perpendicular to) the bottom surface, and the shape of the bottom surface (first surface 111 and second surface 112) may be changed as appropriate. Furthermore, the shapes of the graphite material 10 and the backflow heat prevention structure 20 may be changed as appropriate to match the shape of the base material 110C. That is, the heat transfer member 100C may be a columnar (rod-like) member with the X direction intersecting (e.g., perpendicular to) the bottom surface.

[0070] 12 illustrates an example of a method for manufacturing a heat transfer member. The method for manufacturing the heat transfer member 100A of embodiment 2 is described below. The manufacturing method includes a cutting step J1, a grinding step J2, and a plating step J3.

[0071] In cutting step J1, graphite element 501 is cut using a processing machine such as a wire saw to produce multiple graphite materials 501u. Graphite element 501 generally has two crystal planes, and the dimensions of the crystal planes are greater than the dimensions in a direction perpendicular to the crystal planes. Cut graphite material 501u may be cut so that the minimum width of the crystal planes is smaller than the minimum width of the cut surfaces (i.e., crystal layer surfaces).

[0072] In the grinding step J2, the quadrangular columnar graphite material 501u is ground into a cylindrical shape using a grindstone or the like to produce the base material 110A of the heat transfer member 100A. In the plating step J3, plating is applied to the surface of the base material 110A. This plating layer becomes the protective film 120. Note that instead of (or in addition to) the plating step J3, a thermal spraying step may be performed to form the protective film 120. The heat transfer member 100A is manufactured through the above steps J1 to J3.

[0073] The above describes the embodiments of the present disclosure. However, the heat transfer member and electronic device of the present disclosure are not limited to the heat transfer members 100, 100A, 100B, and 100C and the electronic devices 300 and 400 of the above-described embodiments. For example, the details shown in the embodiments can be modified as appropriate without departing from the spirit of the invention. According to the present disclosure, a heat transfer member and electronic device that do not use a liquid can be obtained.

[0074] In one embodiment of the present disclosure, (1) a heat transfer member includes an elongated substrate extending in an X direction, the substrate including a graphite material having a higher thermal conductivity in the X direction than in a Y direction intersecting the X direction, and the substrate has a first connection portion on one side in the X direction that is a region to which a heat-generating component is connected, and a second connection portion on the other side in the X direction that is a region to which a cooling component is connected.

[0075] (2) The heat transfer member includes an elongated substrate extending in the X direction, the substrate including a graphite material having a higher thermal conductivity in a Z direction intersecting the X and Y directions than in a Y direction intersecting the X direction, the substrate having a first connection portion on one side in the Z direction, which is an area to which a heat-generating component is connected, and a second connection portion on the other side in the Z direction, which is an area to which a cooling component is connected.

[0076] (3) In the heat transfer member according to (1) or (2), the base material has a plurality of the first connection portions.

[0077] (4) The heat transfer member according to any one of (1) to (3) above further comprises a protective film covering the surface of the base material.

[0078] (5) In the heat transfer member of (4) above, the protective film is a metal film.

[0079] (6) The heat transfer member of (4) above is configured such that the protective film includes a first protective film that protects the first connection portion and the second connection portion, and a second protective film that protects an area of ​​the surface of the substrate other than the first connection portion and the second connection portion, the first protective film being a metal film, and the second protective film being a ceramic film or a resin film.

[0080] (7) In the heat transfer member according to any one of (1) to (6) above, the base material includes a plurality of the graphite materials arranged in parallel in the X direction, and a check valve positioned between the graphite materials to prevent a backflow of heat.

[0081] In one embodiment, (8) an electronic device includes: a heat transfer member according to any one of (1) to (7); a heat-generating component connected to the first connection portion; and a cooling component connected to the second connection portion.

[0082] The present disclosure can be used as a heat transfer member and an electronic device.

[0083] 10, 10C Graphite material 20 Backflow heat prevention structure (backflow prevention valve) 100, 100A, 100B, 100C Heat transfer member 110, 110A, 110B, 110C Base material 120 Protective film 160, 180 First connection part 170, 190 Second connection part 300, 400 Electronic device 310, 410 Heat-generating component 320, 420 Cooling component

Claims

1. A heat transfer component comprising an elongated substrate extending in an X direction, the substrate including a graphite material having a higher thermal conductivity in the X direction than in a Y direction intersecting the X direction, the substrate having a first connection portion on one side in the X direction which is an area to which a heat-generating component is connected, and a second connection portion on the other side in the X direction which is an area to which a cooling component is connected.

2. A heat transfer member comprising an elongated substrate extending in an X direction, the substrate including a graphite material having a higher thermal conductivity in a Z direction intersecting the X direction and the Y direction than in a Y direction intersecting the X direction, the substrate having a first connection portion on one side in the Z direction which is an area to which a heat generating component is connected, and a second connection portion on the other side in the Z direction which is an area to which a cooling component is connected.

3. The heat transfer member according to claim 1 or 2, wherein the base material has a plurality of the first connection portions.

4. The heat transfer member according to any one of claims 1 to 3, further comprising a protective film covering the surface of the base material.

5. The heat transfer member according to claim 4, wherein the protective film is a metal film.

6. The heat transfer member according to claim 4, wherein the protective film includes a first protective film that protects the first connection portion and the second connection portion, and a second protective film that protects an area of ​​the surface of the base material other than the first connection portion and the second connection portion, the first protective film being a metal film, and the second protective film being a ceramic film or a resin film.

7. The heat transfer member according to any one of claims 1 to 6, wherein the base material includes: a plurality of the graphite materials arranged in parallel in the X direction; and check valves positioned between the graphite materials for preventing a backflow of heat.

8. An electronic device comprising: a heat transfer member according to any one of claims 1 to 7; a heat generating component connected to the first connection part; and a cooling component connected to the second connection part.

Images