Heat dissipation substrate and heat dissipation device

Abstract

This heat dissipation substrate comprises a base body containing a carbon material, and a plurality of pipe mounting parts positioned on the base body. When the direction in which the plurality of pipe mounting parts are aligned is defined as the X direction, the direction in which the plurality of pipe mounting parts extends is defined as the Y direction, the plane extending in the X direction and the Y direction is defined as the XY plane, and a direction intersecting the XY plane is defined as the Z direction, the thermal conductivity in the Z direction of the substrate is higher than the thermal conductivity in at least one direction along the XY plane of the substrate.

Description

Heat dissipation board and heat dissipation device

[0001] The present disclosure relates to a heat dissipation substrate and a heat dissipation device.

[0002] Japanese Patent Application Laid-Open No. 2010-161177 discloses a heat dissipation device having a structure in which a pipe body of a heat pipe is held by a heat dissipation substrate.

[0003] The heat dissipation substrate of the present disclosure comprises a base containing a carbon material, and a plurality of pipe mounting portions located on the base, wherein when the direction in which the plurality of pipe mounting portions are arranged is referred to as the X direction, the direction in which each of the plurality of pipe mounting portions extends is referred to as the Y direction, a plane extending in the X direction and the Y direction is referred to as the XY plane, and a direction intersecting the XY plane is referred to as the Z direction, the thermal conductivity of the base in the Z direction is higher than the thermal conductivity of the base in at least one direction along the XY plane.

[0004] The heat dissipation device of the present disclosure includes the heat dissipation substrate described above and a heat pipe having a pipe body, the pipe body being mounted on the pipe mounting portion.

[0005] FIG. 1A is a perspective view showing a heat dissipating substrate according to embodiment 1 of the present disclosure. FIG. 1B is an exploded perspective view showing components of the heat dissipating substrate according to embodiment 1 of the present disclosure. FIG. 1C is a cross-sectional view taken along line A-A in FIG. 1A. FIG. 1C is a cross-sectional view taken along line B-B in FIG. 1A. FIG. 1D is a cross-sectional view showing a heat dissipating substrate according to embodiment 2. FIG. 1E is a cross-sectional view showing a heat dissipating substrate according to embodiment 3. FIG. 1F is an exploded perspective view showing a heat dissipating substrate according to embodiment 4. FIG. 4C is a cross-sectional view taken along line A-A in FIG. 4A. FIG. 4C is a cross-sectional view taken along line B-B in FIG. 4A. FIG. 4F is a cross-sectional view showing a heat dissipating substrate according to embodiment 5. FIG. 4G is a cross-sectional view showing a heat dissipating substrate according to embodiment 6. FIG. 4H is an enlarged cross-sectional view showing a heat dissipating substrate according to embodiment 7. FIG. 4H is a cross-sectional view showing a heat dissipating substrate according to embodiment 8. FIG. 4I is a partially enlarged view showing a heat dissipating substrate according to embodiment 8. FIG. 5 is a side view showing a heat dissipating device according to embodiment 1 of the present disclosure. FIG. 5I is a side view showing a heat dissipating device according to embodiment 2 of the present disclosure.

[0006] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0007] 1A and 1B are a perspective view and an exploded perspective view of components of a heat dissipation substrate according to a first embodiment of the present disclosure, respectively. 2A and 2B are cross-sectional views taken along line AA and line BB in FIG. 1A.

[0008] The heat dissipation substrate 10 of the first embodiment has a base 11 containing a carbon material and pipe mounting portions 15a to 15c located on the base 11. The heat dissipation substrate 10 may be a substrate that exerts a heat dissipation effect by quickly transferring heat received from an external heat source to the pipe mounting portions 15a to 15c.

[0009] The base 11 may be a block piece whose main component is graphite. "Main component" may mean a volume ratio of 80% or more. The base 11 may be a block piece whose graphite crystal orientation is aligned. The base 11 may be configured by joining multiple such block pieces. The graphite may be pyrolytic graphite. The graphite may be highly oriented graphite, which has thermal conductivity equivalent to or higher than that of copper or aluminum and anisotropic thermal conductivity. When the base 11 is a block piece of graphite, it is easier to process three-dimensional structures such as the pipe mounting portions 15a-15c compared to sheet-like graphite. Furthermore, the base 11 can support a pipe (e.g., a pipe mounted on the pipe mounting portions 15a-15c). Furthermore, when the base 11 is a block piece of graphite, it is easier to fix the base 11 to a heat source while applying pressure from the base 11. Thermal conductivity can be measured using a laser flash method. When graphite has anisotropic thermal conductivity, "having a thermal conductivity equivalent to or higher than that of copper or aluminum" means having a thermal conductivity equivalent to or higher than that of copper or aluminum in at least one direction. "Having a thermal conductivity equivalent to or higher than that of copper or aluminum" means, for example, a thermal conductivity of 200 W / m·K or higher, more preferably 370 W / m·K or higher, and even more preferably 450 W / m·K or higher. The graphite used in this embodiment may have a thermal conductivity of 800 W / m·K or higher in one direction.

[0010] The heat dissipation substrate 10 may further include a cover member 20 located on the outer surface of the base 11. The base 11 may include, as its outer surface, a first surface 11a, a second surface 11b located opposite the first surface 11a, and multiple side surfaces smaller than the first surface 11a and the second surface 11b. The cover member 20 may be located on multiple outer surfaces of the base 11 (i.e., the first surface 11a, the second surface 11b, and the multiple side surfaces) excluding the pipe mounting portions 15a to 15c. By including the cover member 20, even if the outer surface portion of the base 11 has low strength, this strength can be compensated for by the cover member 20. Therefore, the inclusion of the cover member 20 increases the degree of freedom in selecting the material for the base 11, making it possible to adopt a material that can further improve heat dissipation.

[0011] The thermal conductivity of the base 11 may be higher than that of the cover member 20. This configuration provides high heat diffusibility in the base 11, thereby improving the heat dissipation performance of the heat dissipation substrate 10. If the thermal conductivity of the base 11 is anisotropic, the thermal conductivity of the base 11 in at least the Z direction described below may be higher than the thermal conductivity of the cover member 20. This configuration improves the thermal conductivity in the direction from the second surface 11b of the heat dissipation substrate 10 toward the pipe mounting portions 15a to 15c, thereby improving the heat dissipation performance of the heat dissipation substrate 10.

[0012] The cover member 20 may be made of metal. This configuration can improve the thermal conductivity of the cover member 20 and reduce the reduction in the heat dissipation performance of the heat dissipation substrate 10 caused by the cover member 20. The cover member 20 may include metal plating. The metal plating allows the cover member 20 to cover every detail of the base 11, reducing the risk of fragments of the outer surface of the damaged base 11 being released to the outside. This eliminates the need to increase the hardness of the base 11, thereby increasing the flexibility in the materials used. The cover member 20 may have a thermal conductivity of 90 W / m·K or higher. If the thermal conductivity of the cover member 20 is 90 W / m·K or higher, the reduction in the heat dissipation performance of the heat dissipation substrate 10 caused by the cover member 20 can be further reduced.

[0013] More specifically, the cover member 20 may include a first plate 21 located on the first surface 11a of the base 11, a second plate 22 located on the second surface 11b of the base 11, and metal plating 23 located on the outer peripheral surface of the combined structure of the base 11, the first plate 21, and the second plate 22. The first plate 21 and the second plate 22 provide high strength to the upper and lower surfaces of the heat dissipation substrate 10, making it easy to fix the heat dissipation substrate 10 by pressing the upper or lower surface against a heat source. This fixation improves the thermal conductivity from the heat source to the heat dissipation substrate 10. Furthermore, holding the heat dissipation substrate 10 via the strong upper and lower surfaces makes it easier to handle the heat dissipation substrate 10. Furthermore, since the metal plating 23 is also located on the outside of the first plate 21 and the second plate 22, the metal plating 23 is continuous on the outer peripheral surface of the heat dissipation substrate 10, and the peripheral end portion of the metal plating 23 is less likely to appear on the outer peripheral surface, thereby reducing peeling of the metal plating 23.

[0014] The hardness of the cover member 20 may be higher than the hardness of the base 11. With this configuration, even if an external force is applied to the cover member 20, the force is dispersed and acts on the base 11. Therefore, damage to the base 11 inside the cover member 20 can be reduced. Vickers hardness may be used as the hardness. The hardness of the cover member 20 may be preferably 10 times or more, more preferably 20 times or more, than the hardness of the base 11. The hardness of the cover member 20 may also be preferably 200 MPa or more, more preferably 500 MPa or more, and even more preferably 900 MPa or more. The hardness of the base 11 may be 10 MPa or more and 40 MPa or less. The Vickers hardness can be measured using the measurement method specified in JIS (Japanese Industrial Standards) _Z_2244:2009.

[0015] The first plate 21 and the second plate 22 may be primarily composed of copper or aluminum. Copper or aluminum can be used as the material for the first plate 21 and the second plate 22. Copper has a high thermal conductivity of approximately 370 W / m·K and good processability, making it easy to process the cover member 20. Aluminum has a high thermal conductivity of approximately 200 W / m·K and is lighter than copper, making it possible to reduce the weight of the cover member 20. The metal plating 23 may be made of various metals, such as nickel, gold, or silver. The metal plating 23 may be a single layer or multiple layers. When the metal plating 23 is made of multiple layers, it may be, for example, two layers of gold and nickel. When the metal plating 23 contains gold and nickel, it may also contain a gold-nickel alloy. The first plate 21 and the second plate 22 may be joined to the base 11 via a joining material, such as solder or a thermally conductive resin. This configuration improves the heat dissipation properties of the heat dissipation substrate 10, improves the strength of the heat dissipation substrate 10, reduces damage to the outer surface of the base 11, and better disperses external forces applied to the cover member 20.

[0016] The pipe mounting portions 15a-15c may be configured to mount pipes included in a heat pipe. The heat dissipation substrate 10 may include multiple pipe mounting portions 15a-15c or a single pipe mounting portion. The cross-sectional shape of the pipe mounting portions 15a-15c may be circular, oval, rectangular, polygonal, or a combination thereof. The cross-section may be a vertical cross-section perpendicular to the extension direction of the pipe mounting portions 15a-15c (see FIG. 2A). In this embodiment, the number of the pipe mounting portions 15a-15c is three, but this is not limited to three. The number of the pipe mounting portions 15a-15c may be two, four, or more. Preferably, the number of the pipe mounting portions 15a-15c is three or more. When the number of pipe mounting portions 15a to 15c is three or more, heat can be dispersed to each of the pipe mounting portions 15a to 15c compared to when the number is two or less, so that heat from the base 11 can be more efficiently transferred to the pipe body mounted on the pipe mounting portions 15a to 15c.

[0017] The pipe mounting portions 15a to 15c may be located across the base 11 and the cover member 20. By having a portion of the pipe mounting portions 15a to 15c located on the base 11, the thermal resistance from the base 11 to the pipe can be reduced, and heat can be efficiently transferred to the pipe. This improves the heat dissipation performance of the heat dissipation substrate 10. Furthermore, by having a portion of the pipe mounting portions 15a to 15c located on the cover member 20, the holding strength of the pipe mounted on the pipe mounting portions 15a to 15c can be improved. In the first embodiment, the pipe mounting portions 15a to 15c penetrate the metal plating 23, and a portion of the pipe mounting portions 15a to 15c is located on the metal plating 23.

[0018] Each of the pipe mounting portions 15a to 15c may be a through hole. The pipe mounting portions 15a to 15c, which are through holes, may be located along the first surface 11a of the base 11, between the first surface 11a and the second surface 11b of the base 11. The pipe mounting portions 15a to 15c may penetrate the metal plating 23 on the side surface of the heat dissipation substrate 10. In other words, the inner surfaces of the pipe mounting portions 15a to 15c are not covered by the cover member 20 (e.g., the metal plating 23), and the base 11 may be located on the inner surfaces of the pipe mounting portions 15a to 15c before the pipe is mounted thereon. With this configuration, when a pipe is mounted on the pipe mounting portion 15a to 15c, the base 11, which has high thermal conductivity, is in close proximity to the pipe, allowing heat to be efficiently transferred from the heat dissipation substrate 10 to the pipe. Furthermore, by covering the inner surfaces of the pipe mounting portions 15a to 15c, the pipe body protects the surface portions of the base 11 exposed on the inner surfaces of the pipe mounting portions 15a to 15c, thereby reducing damage to the surface portions of the base 11.

[0019] <Anisotropy of Thermal Conductivity> The base 11 may have anisotropy of thermal conductivity. The anisotropy may be such that the thermal conductivity in one of three mutually orthogonal directions is higher than the thermal conductivity in another of the three mutually orthogonal directions. In this case, the thermal conductivity in one of the three mutually orthogonal directions may be 100 times or more higher than the thermal conductivity in the other of the three mutually orthogonal directions. In this case, the direction of heat conduction can be controlled, thereby facilitating thermal management. More preferably, the anisotropy may be such that the thermal conductivity in two of the three mutually orthogonal directions is higher than the thermal conductivity in the other of the three mutually orthogonal directions. In this case, the thermal conductivity in two of the three mutually orthogonal directions may be 100 times or more higher than the thermal conductivity in the other of the three mutually orthogonal directions. In this case, thermal management is further facilitated. Note that the above three directions do not have to be orthogonal to each other, as long as the remaining direction intersects a plane along two of the directions.

[0020] In the following, the direction in which the multiple pipe mounting portions 15a to 15c are lined up will be referred to as the X direction, the direction in which each of the multiple pipe mounting portions 15a to 15c extends will be referred to as the Y direction, the plane extending in the X and Y directions will be referred to as the XY plane, and the direction intersecting (for example, perpendicular to) the XY plane will be referred to as the Z direction.

[0021] Due to the anisotropy, the thermal conductivity of the base 11 in the Z direction may be higher than the thermal conductivity in at least one direction along the XY plane of the base 11. With this configuration, by arranging a heat source close to the second surface 11b (or the first surface 11a), which has a larger area among the outer surfaces of the base 11, heat received from the heat source can be quickly conducted in the Z direction and sent to the pipe mounting portions 15a-15c. Furthermore, the pipes quickly absorb heat, further improving the heat dissipation performance of the heat dissipation substrate 10. When the thermal conductivity of the base 11 in the Z direction is 100 times or more higher than the thermal conductivity in at least one direction along the XY plane of the base 11, the direction of heat conduction can be more tightly controlled in the Z direction from the heat source toward the pipe mounting portions 15a-15c. Furthermore, it is preferable that the thermal conductivity of the base 11 in the Z direction be higher than the thermal conductivity of the base 11 in the Y direction. In this case, the path that heat takes from the heat source to the pipe can be made shorter than when the thermal conductivity in the Z direction is equal to or less than that in the Y direction, allowing the heat dissipation substrate 10 to dissipate heat more efficiently.

[0022] The thermal conductivity of the base 11 in the X direction may be higher than the thermal conductivity of the base 11 in the Y direction. With this configuration, even if heat from a heat source is concentrated on a portion of the second surface 11b, the heat can be quickly dispersed in the X direction. This action allows the heat to be dispersed and sent to the multiple pipe mounting portions 15a to 15c arranged in the X direction. The multiple pipes then quickly absorb the heat, further improving the heat dissipation performance of the heat dissipation substrate 10. If the thermal conductivity of the base 11 in the X direction is 100 times or more higher than the thermal conductivity of the base 11 in the Y direction, the heat can be more efficiently dispersed and sent to the multiple pipe mounting portions 15a to 15c arranged in the X direction.

[0023] (Embodiments 2 and 3) Fig. 3A is a cross-sectional view showing a heat dissipation substrate according to embodiment 2. Fig. 3B is a cross-sectional view showing a heat dissipation substrate according to embodiment 3. The heat dissipation substrates 10A and 10B according to embodiments 2 and 3 differ mainly in the Z-direction positions of the pipe mounting portions 15a to 15c, which are through holes, but other components may be the same as those of embodiment 1.

[0024] As in the second embodiment (see FIG. 3A) and the third embodiment (see FIG. 3B), the through-holes of the pipe mounting portions 15a-15c may be positioned offset from the center of the base 11 in the Z direction. Specifically, when focusing on one of the pipe mounting portions 15b (corresponding to the first pipe mounting portion) among the multiple pipe mounting portions 15a-15c, the distance L1 from the pipe mounting portion 15b to the first surface 11a may be different from the distance L2 from the pipe mounting portion 15b to the second surface 11b. The distance refers to the length between the closest points. With this configuration, by placing the surface with the shorter distance (the second surface 11b in FIGS. 3A and 3B) closer to the heat source, the thermal resistance from the heat source to the pipe mounting portion 15b can be reduced, allowing heat to be efficiently transferred to the pipe body. This further improves the heat dissipation performance of the heat dissipation substrate 10. In addition, the long distance L1 to the opposite surface (first surface 11a in FIGS. 3A and 3B) ensures the height of heat dissipation substrate 10. By ensuring the height of heat dissipation substrate 10, the strength of heat dissipation substrate 10 can be improved.

[0025] The relationship between the distances L1 and L2 may be a relationship that holds true in any longitudinal cross section in the Y direction, or may be a relationship that holds true in a partial range of longitudinal cross sections in the Y direction. The longitudinal cross section means a cross section perpendicular to the Y direction. The more locations where the relationship between the distances L1 and L2 holds true, the greater the range in which the effects of the distances L1 and L2 can be obtained.

[0026] Furthermore, the relationship between the distances L1 and L2 may be established for only one pipe mounting portion 15 b, or may be established for any or all of the multiple pipe mounting portions 15 a to 15 c. The more pipe mounting portions 15 a to 15 c for which the relationship between the distances L1 and L2 is established, the wider the range in which the effects of the distances L1 and L2 can be obtained.

[0027] The base 11 of the second and third embodiments may have a configuration including two layers of block pieces 111, 112. The layer refers to a layer extending in a direction along the XY plane. A bonding material 118 may be positioned between the two layers of block pieces 111, 112. The bonding material 118 may be solder, a thermally conductive adhesive, a thermally conductive filler (such as grease), or the like. With this configuration, the height of the base 11 can be easily ensured.

[0028] The thicknesses T1 and T2 of the two layers of block pieces 111 and 112 may be the same as each other as shown in Fig. 3A, or may be different as shown in Fig. 3B. In either case, the relationship between the distances L1 and L2 described above can be realized.

[0029] When two layers of block pieces 111 and 112 are provided, the thicknesses T1 and T2 of each block piece 111 and 112 may be greater than half the Z-direction dimension T15 of the pipe mounting portions 15a to 15c. The boundary surface where the bonding material 118 is located may be located at a position halfway along the Z-direction of the pipe mounting portions 15a to 15c, or closer to the first surface 11a than that position. This configuration places the second surface 11b close to the heat source, increasing the proportion of the surface facing the pipe mounting portions 15a to 15c and the block piece 112 closer to the heat source. Because the bonding material 118 has a lower thermal conductivity than the block pieces 111 and 112 alone, heat stagnation occurs at the bonding material 118 when heat is conducted in the Z-direction of the base 11. Therefore, with this configuration, more heat is absorbed by the pipe body before heat stagnation occurs, further improving the heat dissipation performance of the heat dissipation substrate 10.

[0030] Even in the case of two-layer block pieces 111, 112, the thermal conductivity in the Z direction may be higher than the thermal conductivity in at least one direction along the XY plane in each of the block pieces 111, 112. Furthermore, the thermal conductivity in the X direction may be higher than the thermal conductivity in the Y direction. With this configuration, the effect of the anisotropy of thermal conductivity described in the first embodiment is similarly achieved.

[0031] 4A and 4B are an exploded perspective view and a perspective view showing a heat dissipation substrate according to embodiment 4. Figures 5A and 5B are cross-sectional views taken along line AA in Figure 4A and line BB in Figure 4A.

[0032] The heat dissipation substrate 10C of the fourth embodiment differs mainly in the configuration of the pipe mounting portions 16a to 16c. Of the heat dissipation substrate 10C of the fourth embodiment, components having the same reference numerals as those of the first embodiment may be the same as those of the heat dissipation substrate 10 of the first embodiment unless otherwise specified.

[0033] The heat dissipation substrate 10C may have pipe mounting portions 16a to 16c that are grooves. The cross-sectional shape of the pipe mounting portions 16a to 16c may be a circular arc, an oval arc, a rectangular shape, a polygonal shape including a V-shape, or the like. The above cross section may refer to a longitudinal cross section perpendicular to the direction in which the pipe mounting portions 16a to 16c extend. By using the pipe mounting portions 16a to 16c as grooves, the process of combining the pipe body with the heat dissipation substrate 10C can be simplified.

[0034] The pipe mounting portions 16a to 16c may be located on the first surface 11a side of the base 11. With this arrangement, the second surface 11b side can be made flat with the pipes mounted on the pipe mounting portions 16a to 16c, making it easier to place a heat source close to the second surface 11b side. This shortens the distance between the heat source and the pipe mounting portions 16a to 16c, and reduces the thermal resistance from the heat source to the pipe mounting portions 16a to 16c.

[0035] The pipe mounting portions 16a-16c may be located across the base 11 and the cover member 20. That is, as shown in FIG. 5A, in a vertical cross section perpendicular to the direction in which the pipe mounting portions 16a-16c extend, the cover member 20 located on the surface may be divided by the pipe mounting portions 16a-16c (e.g., grooves). The base 11 located below the cover member 20 may be located (e.g., exposed) at the bottom of the pipe mounting portions 16a-16c (e.g., the bottom of the grooves). By locating the base 11 on at least a portion of the inner surface of the pipe mounting portions 16a-16c, the base 11, which has high thermal conductivity, can be placed close to the pipes, allowing heat to be efficiently transferred from the base 11 to the pipes. This improves the heat dissipation performance of the heat dissipation substrate 10C.

[0036] In the following, the direction in which the multiple pipe mounting portions 16a to 16c are lined up will be referred to as the X direction, the direction in which each of the multiple pipe mounting portions 16a to 16c extends will be referred to as the Y direction, the plane extending in the X and Y directions will be referred to as the XY plane, and the direction intersecting (e.g., perpendicular to) the XY plane will be referred to as the Z direction.

[0037] The thermal conductivity of the base 11 in the Z direction may be higher than the thermal conductivity in at least one direction along the XY plane of the base 11. With this configuration, the heat from the heat source received from the second surface 11b can be quickly conducted in the Z direction and sent to the pipe mounting portions 16a to 16c. The pipes quickly absorb the heat, further improving the heat dissipation performance of the heat dissipation substrate 10C.

[0038] The thermal conductivity of the base 11 in the X direction may be higher than the thermal conductivity of the base 11 in the Y direction. With this configuration, even if heat from a heat source is concentrated on a portion of the second surface 11b, the heat can be quickly dispersed in the X direction. This action allows the heat to be dispersed and sent to the multiple pipe mounting portions 16a to 16c arranged in the X direction. Furthermore, the multiple pipes quickly absorb heat, further improving the heat dissipation performance of the heat dissipation substrate 10C.

[0039] The pipe mounting portions 16a-16c, which are grooves, may be located from one end to the other end of the heat dissipation substrate 10C in the Y direction. Alternatively, the pipe mounting portions 16a-16c, which are grooves, may be located only in a partial range in the Y direction. For example, the pipe mounting portions 16a-16c, which are grooves, may be located only in the central region in the Y direction, and the pipes may be mounted so that they are in contact with or spaced apart from the upper surface of the heat dissipation substrate 10C at one and the other ends in the Y direction. Alternatively, the pipe mounting portions 16a-16c, which are grooves, and the pipe mounting portions 16a-16c, which are through-holes, may be connected in the Y direction, and the pipes may be mounted over the grooves and through-holes. Note that "upper" does not necessarily have to correspond to the up-down relationship in actual use. For example, "upper" refers to the direction from the second surface 11b toward the first surface 11a of the heat dissipation substrate 10C in the Z direction.

[0040] The pipe bodies 61a to 61c may be joined to the pipe mounting portions 16a to 16c via a joining material such as solder or a thermally conductive adhesive, or may be positioned via a thermally conductive filler (for example, grease).

[0041] The heat dissipation substrate 10C may include a metal plate 30 (see FIG. 4A) covering at least a portion of the pipe mounting portions 16a-16c from above. The metal plate 30 holds the pipes 61a-61c mounted on the pipe mounting portions 16a-16c by sandwiching them from above. In addition, the metal plate 30 may have the function of receiving heat from the cover member 20 and sending it to the pipes 61a-61c by being in close proximity to the upper portions of the pipes 61a-61c of the heat dissipation substrate 10C. This configuration allows heat to be sent to the pipes 61a-61c from the opposite side of the pipe mounting portions 16a-16c, improving the heat dissipation performance of the heat dissipation substrate 10C even when the pipe mounting portions 16a-16c are grooves.

[0042] The material of the metal plate 30 may be mainly composed of copper, aluminum, or the like. Copper has a high thermal conductivity of about 370 W / m·K and good workability, making it easy to process the cover member 20. Aluminum has a high thermal conductivity of about 200 W / m·K and is lighter than copper, making it possible to reduce the weight of the cover member 20.

[0043] The metal plate 30 may have a main body portion 31 located above the pipe mounting portions 16a to 16c, and a flange portion 32 connected to the peripheral edge of the main body portion 31. The flange portion 32 may be joined to the cover member 20 to fix the metal plate 30. A thermally conductive filler (e.g., grease) 44 (see FIG. 7) may be positioned between the main body portion 31 of the metal plate 30 and the pipes 61a to 61c. This configuration simplifies the process of mounting the pipes 61a to 61c and the process of fixing the metal plate 30.

[0044] 6A is a cross-sectional view showing a heat dissipation substrate according to embodiment 5. A heat dissipation substrate 10D of embodiment 5 may be similar to embodiment 4 except for the fixing structure of the metal plate 30.

[0045] 6A, the flange portion 32 may be joined to the cover member 20 on the first surface 11a side via a bonding material 41 such as solder or a thermally conductive adhesive. With this configuration, heat conducted to the first surface 11a side via the base 11 and the cover member 20 can be sent to the pipes 61a-61c via the flange portion 32 and the main body 31 of the metal plate 30. Therefore, even if the pipe mounting portions 16a-16c are grooves and a portion (e.g., the upper portion) of the pipes 61a-61c is separated from the base 11 or the cover member 20, heat can be absorbed from the separated portion. This further improves the heat dissipation performance of the heat dissipation substrate 10C.

[0046] 6B is a cross-sectional view showing a heat dissipation substrate according to embodiment 6. A heat dissipation substrate 10E of embodiment 6 may be the same as embodiment 4 except that the fixing structure of the metal plate 30 is different.

[0047] As shown in FIG. 6B , the flange portion 32 may be configured to be screwed to the combined structure of the base 11 and the cover member 20. That is, the combined structure of the base 11 and the cover member 20 may have a screw hole 18 at a location overlapping the flange portion 32, and the flange portion 32 may have a screw hole 33 at a corresponding location. The screw hole 18 may have a female thread at the position of the second plate 22 or the position of the first plate 21. The screw hole 18 may penetrate the base 11 and the cover member 20 from the first surface 11a to the second surface 11b. This configuration allows the metal plate 30 to be fixed with a screw, simplifying the process of fixing the metal plate 30. Furthermore, the durability of the fixing structure of the metal plate 30 can be improved. In addition, the thermal resistance at the connection point between the flange portion 32 and the cover member 20 is reduced, contributing to improved heat dissipation of the heat dissipation board 10E.

[0048] Seventh Embodiment Fig. 7 is an enlarged cross-sectional view showing a heat dissipation substrate of a seventh embodiment. The heat dissipation substrate 10F of the seventh embodiment may be the same as those of the fourth to sixth embodiments, except that the positions of the pipe mounting portions 16a to 16c, which are grooves, in the Z direction (i.e., the depth direction) are different. Fig. 7 shows an example in which the joining structure of the metal plate 30 of the fifth embodiment is adopted, but the joining structure of the sixth embodiment may also be adopted.

[0049] Pipes 61a to 61c are mounted on the pipe mounting portions 16a to 16c. As shown in FIG. 7, in a longitudinal cross section, the length of an opposing portion 63 between the pipes 61a to 61c and the base 11 and cover member 20 may be greater than the length of an opposing portion 62 between the pipes 61a to 61c and the metal plate 30. In FIG. 7, the opposing portions 62, 63 are indicated by thick dashed lines and thick solid lines. The aforementioned longitudinal cross section refers to a cross section of the portion where the pipe mounting portions 16a to 16c are covered by the metal plate 30 and is perpendicular to the direction in which the pipe mounting portions 16a to 16c extend. When a heat source is located close to the second surface 11b, the path of heat transfer from the heat source to the pipes 61a to 61c via the base 11 and cover member 20 has lower thermal resistance than the path of heat transfer via the metal plate 30. Therefore, the size relationship between the opposing portions 62 and 63 reduces the overall thermal resistance from the heat source to the pipes 61 a to 61 c, and heat can be efficiently transferred to the pipes 61 a to 61 c, thereby further improving the heat dissipation performance of the heat dissipation board 10F.

[0050] The size relationship between the opposing portions 62 and 63 may be a relationship that holds from one end to the other end of the metal plate 30 in the Y direction, or may hold only in a partial range. The more locations where the size relationship between the opposing portions 62 and 63 holds, the more range in which the above-mentioned effect can be obtained.

[0051] 8A and 8B are a cross-sectional view and a partially enlarged view showing a heat dissipation substrate of embodiment 8. The heat dissipation substrate 10G of embodiment 8 may be the same as those of embodiments 4 to 7, except that the positions of the pipe mounting portions 16a to 16c, which are grooves, in the Z direction (i.e., the depth direction) are different. Although the metal plate 30 is omitted in FIG. 8, the configuration and fixing structure of the metal plate 30 may be the same as those of embodiments 4 to 7.

[0052] As shown in FIG. 8 , in a longitudinal cross section, the length of an opposing portion 66 between the pipes 61a-61c and the base 11 may be greater than the length of an opposing portion 65 between the pipes 61a-61c and the cover member 20. In FIG. 8 , the opposing portions 65, 66 are indicated by thick dashed and solid lines. The aforementioned longitudinal cross section refers to a cross section of the portion where the pipe mounting portions 16a-16c are covered by the metal plate 30 and is perpendicular to the direction in which the pipe mounting portions 16a-16c extend. Because the thermal conductivity of the base 11 is higher than that of the cover member 20, when a heat source is close to the second surface 11b, the heat conduction path from the heat source to the pipes 61a-61c via the opposing portion 66 has lower thermal resistance than the heat conduction path via the cover member 20 and the opposing portion 65. Therefore, the size relationship between the opposing portions 65 and 66 can reduce the overall thermal resistance from the heat source to the pipe body, thereby further improving the heat dissipation performance of the heat dissipation board 10G.

[0053] The size relationship between the opposing portions 65, 66 may be a relationship that holds true in any longitudinal cross section from one end to the other end in the Y direction of the base 11, or may be a relationship that holds true at at least one location between the one end and the other end. The more locations where the size relationship between the opposing portions 65, 66 holds true, the greater the range over which the above-mentioned effect can be obtained.

[0054] (Heat Dissipation Device) Fig. 9A is a side view of a heat dissipation device according to embodiment 1 of the present disclosure. Fig. 9B is a side view of a heat dissipation device according to embodiment 2 of the present disclosure. Figs. 9A and 9B show a state in which a heat dissipation device 100, 100A is attached to a heat-generating electronic device (e.g., a CPU: Central Processing Unit) 200.

[0055] The heat dissipation device 100 of the first embodiment includes the heat dissipation substrate 10 of the first embodiment described above and a heat pipe 60. The heat pipe 60 has pipe bodies 61a to 61c, which are mounted on pipe mounting portions 15a to 15c. The heat dissipation substrate 10 may be replaced with the heat dissipation substrates 10A and 10B of the second and third embodiments.

[0056] The heat dissipation device 100A of the second embodiment includes the heat dissipation substrate 10C of the fourth embodiment described above and a heat pipe 60. The heat pipe 60 has pipe bodies 61a to 61c, which are mounted on pipe mounting portions 16a to 16c and are partially covered by a metal plate 30. The heat dissipation substrate 10C may be replaced with the heat dissipation substrates 10D to 10G of the fifth to eighth embodiments.

[0057] The heat dissipation device 100, 100A may further include one or both of a heat sink thermally connected to the heat pipe 60 and a cooling mechanism (for example, a cooling fan, a coolant circuit, etc.).

[0058] In the heat dissipation devices 100 and 100A, the outer surface of the base 11 of the heat dissipation substrate 10 and 10C may be covered by the cover member 20, and the inner surfaces of the pipe mounting portions 15a to 15c and 16a to 16c may be covered by the pipes 61a to 61c. With this configuration, the outer surface of the base 11 is not exposed to the outside. Therefore, even if a material that has high thermal conductivity but does not necessarily require improved hardness on the outer surface is used for the base 11, the outer surface of the base 11 can be protected and damage to the base 11 can be reduced.

[0059] The pipes 61a to 61c may be made of metal. A thermally conductive filler 51 may be filled between the outer peripheral surfaces of the pipes 61a to 61c and the inner surfaces of the pipe mounting portions 15a to 15c and 16a to 16c. The filler 51 may be a hardening material (i.e., a bonding material) such as solder or a thermally conductive resin adhesive, or a non-hardening material such as thermally conductive grease.

[0060] The electronic device 200 may include a semiconductor element 210 and a heat spreader 222. Furthermore, the heat spreader 222 may function as a package that houses the semiconductor element 210. The heat spreader 222 may be in surface contact with the semiconductor element 210 via thermally conductive grease 55 or the like.

[0061] The heat dissipation device 100, 100A may be mounted such that the second surface 11b side of the heat dissipation substrate 10 is in surface contact with the heat spreader 222 via the thermally conductive grease 53.

[0062] The heat dissipation devices 100, 100A configured as described above receive heat from the heat-generating electronic device 200 via the heat dissipation substrates 10, 10C, and the heat is efficiently transferred from the heat dissipation substrates 10, 10C to the heat pipes 60, which then dissipate the heat to the outside via the heat pipes 60. Therefore, high heat dissipation performance can be achieved to accommodate the electronic device 200 that generates a large amount of heat.

[0063] Although the embodiments of the present disclosure have been described above, the heat dissipation substrate and heat dissipation device of the present disclosure are not limited to the above embodiments. For example, in the above embodiments, the cover member 20 is shown to include the first and second metal plates 21 and 22 and the metal plating 23. However, the first and second plates 21 and 22 may be omitted and the metal plating may be used as the cover member. Furthermore, a film-like or plate-like resin may be used as the cover member. Other details shown in the embodiments may be modified as appropriate.

[0064] An embodiment of the present disclosure is described below. In one embodiment, (1) a heat dissipation substrate includes a base containing a carbon material and a plurality of pipe mounting portions located on the base, where the direction in which the plurality of pipe mounting portions are arranged is referred to as the X direction, the direction in which each of the plurality of pipe mounting portions extends is referred to as the Y direction, a plane extending in the X direction and the Y direction is referred to as the XY plane, and a direction intersecting the XY plane is referred to as the Z direction, the thermal conductivity of the base in the Z direction is higher than the thermal conductivity of the base in at least one direction along the XY plane. (2) In the heat dissipation substrate of (1) above, the thermal conductivity of the base in the X direction is higher than the thermal conductivity of the base in the Y direction. (3) The heat dissipation substrate of (1) or (2) above, wherein the base has a first surface located on one side in the Z direction and a second surface located on the other side in the Z direction, the plurality of pipe mounting portions include a first pipe mounting portion, and the distance from the first pipe mounting portion to the first surface is different from the distance from the first pipe mounting portion to the second surface. (4) The heat dissipation substrate of any one of (1) to (3) above, wherein each of the plurality of pipe mounting portions is a through hole. (5) The heat dissipation substrate of any one of (1) to (3) above, wherein the base has a first surface located on one side in the Z direction, and each of the plurality of pipe mounting portions is a groove located on the first surface. (6) The heat dissipation substrate of (5) above, further includes a metal plate covering at least a portion of the plurality of pipe mounting portions from above the groove. (7) The heat dissipation substrate of (6) above, further includes a metal cover member located on the outer surface of the base, and the cover member has a screw hole into which the metal plate can be screwed. In one embodiment, (8) a heat dissipation device includes the heat dissipation substrate of (7) and a heat pipe including a plurality of pipes mounted on the plurality of pipe mounting portions, wherein in a vertical cross section of the range where the plurality of pipe mounting portions are covered by the metal plate, the length of the opposing portions of the plurality of pipes to the base and the cover member is longer than the length of the opposing portions of the metal plate to the plurality of pipes. (9) In the heat dissipation device of (8) above, in the vertical cross section, the length of the opposing portions of the plurality of pipes to the base is longer than the length of the opposing portions of the plurality of pipes to the cover member.(10) In the heat dissipation device of (8) or (9) above, the pipe body is made of metal, and a thermally conductive filler is positioned between the pipe body and the base.

[0065] The present disclosure can be used for a heat dissipation substrate and a heat dissipation device.

[0066] 10, 10A to 10G Heat dissipation substrate 11 Base body 11a First surface 11b Second surface 111, 112 Block piece 118 Bonding material 15a to 15c, 16a to 16c Pipe mounting portion 18 Screw hole 20 Cover member 21 First plate 22 Second plate 23 Metal plating 30 Metal plate 31 Main body portion 32 Flange portion 33 Screw hole 41 Bonding material 44, 51 Filler 60 Heat pipe 61a to 61c Pipe body 62, 63, 65, 66 Opposing portion L1, L2 Distance T1, T2 Thickness 100, 100A Heat dissipation device 200 Electronic device

Claims

1. A substrate containing a carbon material, A plurality of pipe mounting portions located on the substrate, Comprising, When the direction in which the plurality of pipe mounting portions are arranged is the X direction, the direction in which each of the plurality of pipe mounting portions extends is the Y direction, the plane extending in the X direction and the Y direction is the XY plane, and the direction intersecting the XY plane is called the Z direction, The thermal conductivity of the substrate in the Z direction is higher than the thermal conductivity in at least one direction along the XY plane of the substrate, A heat dissipation substrate.

2. The thermal conductivity of the substrate in the X direction is higher than the thermal conductivity of the substrate in the Y direction, The heat dissipation substrate according to Claim 1.

3. The substrate has a first surface located on one side in the Z direction and a second surface located on the other side in the Z direction, The plurality of pipe mounting portions include a first pipe mounting portion, The distance from the first pipe mounting portion to the first surface is different from the distance from the first pipe mounting portion to the second surface, The heat dissipation substrate according to Claim 1 or Claim 2.

4. Each of the plurality of pipe mounting portions is a through hole, The heat dissipation substrate according to Claim 1 or Claim 2.

5. The substrate has a first surface located on one side in the Z direction, Each of the plurality of pipe mounting portions is a groove located on the first surface, The heat dissipation substrate according to Claim 1 or Claim 2.

6. Further comprising a metal plate covering at least a part of the plurality of pipe mounting portions from above the grooves, The heat dissipation substrate according to Claim 5.

7. Further comprising a metal cover member located on the outer surface of the substrate, The cover member has a screw hole through which the metal plate can be screwed, The heat dissipation substrate according to Claim 6.

8. The heat dissipation substrate according to Claim 7, A heat pipe including a plurality of pipe bodies mounted on the plurality of pipe mounting portions, Comprising, In the longitudinal section of the range where the plurality of pipe mounting portions are covered by the metal plate, The length of the opposing portions of the plurality of pipe bodies, the substrate, and the cover member is greater than the length of the opposing portions of the metal plate and the plurality of pipe bodies, A heat dissipation device.

9. In the longitudinal section, the length of the opposing portion of the plurality of pipe bodies and the substrate is greater than the length of the opposing portion of the plurality of pipe bodies and the cover member, The heat dissipation device according to Claim 8.

10. The pipe body is made of metal, and a filler having thermal conductivity is located between the pipe body and the substrate, The heat dissipation device according to Claim 8.