Heat transmission device and circuit board

Abstract

To provide a heat transmission device capable of effectively transporting a heat from a heat source to a heat dissipation member arranged at a position to be separated from them.SOLUTION: A heat transmission device is a heat transmission device for transporting a heat generated in a heat source toward a heat dissipation member, and comprises: a first transportation member that includes a heat suction surface contacted to the heat source, and is extended to a direction from the heat suction surface; and a second transportation member that is extended from a bonding part with the first transportation member to the heat dissipation member, and is contacted to the heat dissipation member. In an end part of the first transportation member, a pair of first projection parts arranged with an interval is formed. In the end part of the second transportation member, a second projection part inserted into the pair of first projection parts is formed.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a heat-transfer device and a circuit board. [Background technology]

[0002] For example, in order to transfer heat from a heat generating element, which is a heat source arranged on a substrate of an electronic circuit or an electric circuit, to a heat dissipation member (heat sink), a device described in the following Patent Document 1 has been proposed. In this device, when the heat dissipation member cannot be arranged near the heat generating element, a method is adopted in which the heat dissipation member is connected so as to be perpendicular to the surface direction of the heat generating element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-184693 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in actual circuit design and heat dissipation design, there may be cases where the heat generating element as the heat source is far away from the heat dissipation member, in which case a technology is required to efficiently transfer heat across the distance between the heat source and the heat dissipation member.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a heat transfer device and a circuit board capable of efficiently transferring heat to a heat dissipation member located at a position separated from a heat source. [Means for solving the problem]

[0006] In order to solve the above problems, the heat transfer device disclosed herein is a heat transfer device for transferring heat generated at a heat source toward a heat dissipation member, and comprises a first transfer member having a heat absorption surface in contact with the heat source and extending in one direction from the heat absorption surface, and a second transfer member extending from a joint with the first transfer member to the heat dissipation member and having a heat dissipation surface in contact with the heat dissipation member, wherein a pair of first protrusions are formed on an end of the first transfer member, and a second protrusion is formed on an end of the second transfer member and is inserted between the pair of first protrusions.

[0007] A circuit board according to the present disclosure includes the above-described heat transfer device, and a substrate on which the heat transfer device, a heat generating element serving as the heat source, and a heat sink serving as the heat dissipation member are provided. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a heat transfer device and a circuit board capable of efficiently transferring heat to a heat dissipation member disposed at a position separated from a heat source. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a plan view illustrating a configuration of a heat-transport device and a substrate according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 1 is an exploded perspective view illustrating a configuration of a heat-transfer device according to an embodiment of the present disclosure. [Figure 4] FIG. 2 is a schematic diagram showing a graphite stacking direction of a first conveying member according to an embodiment of the present disclosure. [Diagram 5] FIG. 13 is a schematic diagram showing a graphite stacking direction of a second conveying member according to an embodiment of the present disclosure. [Figure 6] FIG. 2 is an explanatory diagram showing dimensions of each part of a heat-transfer device according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8]FIG. 7 is a cross-sectional view taken along line VIII-VIII in FIG. [Figure 9] FIG. 13 is a perspective view of a first variation of a heat-transfer device according to an embodiment of the present disclosure. [Figure 10] FIG. 13 is a plan view illustrating a second modification of a heat-transport device and a substrate according to an embodiment of the present disclosure. [Figure 11] FIG. 13 is a cross-sectional view illustrating a third modification of a heat-transport device and a substrate according to an embodiment of the present disclosure. [Figure 12] FIG. 13 is a cross-sectional view illustrating a fourth modification of a heat-transport device and a substrate according to an embodiment of the present disclosure. [Figure 13] FIG. 13 is a plan view illustrating a fifth modified example of a heat-transfer device according to an embodiment of the present disclosure. [Figure 14] FIG. 13 is a plan view illustrating a sixth modification of a heat-transfer device according to an embodiment of the present disclosure. [Figure 15] FIG. 13 is a plan view illustrating a seventh modification of a heat-transfer device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A heat transfer device 1 according to a first embodiment of the present disclosure will be described below with reference to Fig. 1 to Fig. 8. The heat transfer device 1 is used to transfer heat to a heat dissipation member 22 (heat sink) located at a distance from a heat generating element 21 (circuit element) serving as a heat source, for example, by being provided alongside a substrate 2 on which an electronic circuit or an electric circuit is mounted. A circuit substrate 100 includes the substrate 2 and the heat transfer device 1.

[0011] (Configuration of Board 2) 1 and 2, the substrate 2 is, for example, in the form of a rectangular plate in a plan view. Heat generating elements 21 are mounted on at least one surface of the substrate 2. The heat generating elements 21 are heat sources that generate heat due to internal resistance when a current flows through them. Of these heat generating elements 21, those that particularly require heat dissipation (cooling) have their heat dissipated to the heat dissipation member 22 via the heat transfer device 1.

[0012] In the example of FIG. 1 and FIG. 2, the heat dissipation member 22 is mounted on the surface opposite to the surface on which the heat generating element 21 as a heat source is provided. In addition, in a plan view, the heat generating element 21 and the heat dissipation member 22 are largely separated from each other. Specifically, the heat generating element 21 is provided near one corner of the substrate 2, while the heat dissipation member 22 is mounted on the surface opposite the corner diagonally opposite thereto. This is because, for example, the cooling fluid that receives heat from the heat dissipation member cannot be drawn near the heat generating element 21, and the heat dissipation member 22 needs to be disposed at a position separated from the heat generating element 21. In addition, when another element 23 having a lower heat resistance than the heat generating element 21 is mounted, the heat transfer device 1 is disposed so as to bypass the other element 23.

[0013] Although not shown in detail, the heat dissipation member 22 is a heat sink having a plate-shaped base provided on the substrate 2 side and a plurality of pins and fins extending in a direction perpendicular to the base. The heat dissipation member 22 is desirably formed integrally from a metal material having high thermal conductivity, such as copper or aluminum.

[0014] (Configuration of heat transfer device 1) Next, a description will be given of the configuration of the heat transfer device 1. The heat transfer device 1 includes a first transfer member 11, a second transfer member 12, and a heat diffusion member 13.

[0015] The first transfer member 11 and the second transfer member 12 are each formed of plate-like graphite and embedded inside the substrate 2. The first transfer member 11 and the second transfer member 12 are connected in a direction intersecting each other to form a heat dissipation path from the heat generating element 21 as a heat source to the heat dissipation member 22 while bypassing the other elements 23. In the example of Fig. 1, the first transfer member 11 and the second transfer member 12 are connected so as to be perpendicular to each other.

[0016] As shown in FIG. 3, the first transport member 11 has a first main body 31 and a pair of first protrusions 32. The first main body 31 is plate-shaped. The first protrusions 32 are thin plate-shaped protruding from one end face of the first main body 31, and are provided in a pair at an interval in a direction perpendicular to the heat absorbing surface 51 in contact with the heat generating element 21. That is, a certain gap is formed between the first protrusions 32. The second transport member 12 has a second main body 41 and only one second protrusion 42. The second main body 41 is plate-shaped like the first main body 31. The second protrusion 42 is thin plate-shaped protruding from the center in the thickness direction on one end face of the second main body 41. The second protrusion 42 is inserted into the gap between the first protrusions 32. As a result, the first transport member 11 and the second transport member 12 are connected to each other so as to be perpendicular to each other. It is desirable that the distance between the pair of first protruding portions 32 be set to be equal to or slightly larger than the thickness of the second protruding portion 42 .

[0017] Furthermore, as shown microscopically in FIG. 4, in a perspective view from the same angle as FIG. 3, the stacking direction of the crystal structure of graphite forming the first transfer member 11 is a direction D2 perpendicular to both the extension direction (longitudinal direction) of the first transfer member 11 and the direction in which the first protrusion 32 and the second protrusion 42 overlap. Also, as shown in FIG. 5, the stacking direction of the crystal structure of graphite forming the second transfer member 12 is a direction D1 perpendicular to both the extension direction (longitudinal direction) of the second transfer member 12 and the direction in which the first protrusion 32 and the second protrusion 42 overlap. Here, it is known that the thermal conductivity is high within the same layer in graphite, while the thermal conductivity is low between layers. That is, in the above configuration, at the connection portion between the first transfer member 11 and the second transfer member 12, the thermal conductivity in the direction in which heat is dissipated from the first transfer member 11 to the second transfer member 12 and the thermal conductivity in the direction in which the second transfer member 12 receives heat from the first transfer member 11 are both high.

[0018] 6 to 8, the longitudinal dimension of first transfer member 11 is t1, the longitudinal dimension of second transfer member 12 is t2, the overlapping area of ​​first transfer member 11 and second transfer member 12 in plan view is A, the cross-sectional area of ​​first transfer member 11 as viewed from the longitudinal direction is B1, and the cross-sectional area of ​​second transfer member 12 as viewed from the longitudinal direction is B2. At this time, it is desirable to set the dimensions of each part so as to satisfy the relationship of the following formula (1). A(t1 / B1+t2 / B2)>1[m] (1)

[0019] The heat diffusion member 13 is provided between the heat generating element 21 as a heat source and the surface (heat absorbing surface 51) of the first transfer member 11, and between the heat dissipation member 22 and the surface (heat dissipation surface 52) of the second transfer member 12. The heat diffusion member 13 is a plate-like member made of graphite, similar to the first transfer member 11 and the second transfer member 12. The stacking direction of the crystal structure of graphite forming the heat diffusion member 13 is preferably a direction perpendicular to the joining direction between the heat diffusion member 13 and the heat absorbing surface 51 or the heat dissipation surface 52, and more preferably a direction in which the first transfer member 11 or the second transfer member 12 extends (longitudinal direction). In addition, the area of ​​the heat diffusion member 13 in plan view is preferably set to be larger than the areas of the heat generating element 21 and the heat dissipation member 22.

[0020] (Action and effect) Here, when designing the heat dissipation of the board 2, it is considered desirable to attach the heat dissipation member 22 directly to the heat generating element 21, which is the heat source. However, in actual circuit design and heat dissipation design, there may be cases where the element and the heat dissipation member 22 are far apart. In this case, a technique is required to efficiently transfer heat while bypassing other elements 23, which have lower heat resistance than the heat generating element 21, during the distance from the element as the heat source to the heat dissipation member 22. Therefore, the above-mentioned configurations are adopted in this embodiment.

[0021] According to the above configuration, by fitting the second protruding portion 42 of the second transfer member 12 between the first protruding portions 32 of the first transfer member 11, both sides of the second protruding portion 42 come into contact with the first protruding portions 32, and the contact area between the first transfer member 11 and the second transfer member 12 can be increased. This allows the first transfer member 11 and the second transfer member 12 to efficiently transfer heat toward the heat dissipation member 22 located away from the heat source, while bypassing other elements 23. Therefore, even if it is difficult to place the heat dissipation member 22 near the heat source, the heat dissipation effect of the heat dissipation member 22 can be easily obtained.

[0022] Here, the thermal conductivity of graphite tends to be relatively high inside the layer made of a crystalline structure, but relatively low between the layers. According to the above configuration, the graphite of the first transfer member 11 maintains a high thermal conductivity in the direction from the heat absorption surface 51 toward the joint surface with the second transfer member, and the graphite of the second transfer member 12 maintains a high thermal conductivity in the direction from the joint surface with the first transfer member toward the heat dissipation surface 52. As a result, even if the first transfer member 11 and the second transfer member 12 are connected in a direction intersecting each other, it is possible to efficiently transfer heat toward the heat dissipation member 22 without dissipating heat to the surroundings. Therefore, the cooling effect on the heat source can be further improved.

[0023] According to the above configuration, the first transfer member 11 and the second transfer member 12 are embedded inside the substrate 2, so that these members can be protected from external shocks and vibrations. This is particularly advantageous when the first transfer member 11 and the second transfer member 12 are made of a brittle material such as graphite. This can increase the availability of the heat transfer device 1. In addition, since the heat transfer device 1 does not protrude from the substrate 2, it is possible to keep the overall dimensions of the substrate 2 small. This can realize the miniaturization of the device to which the substrate 2 is applied.

[0024] According to the above configuration, by setting the dimensions of each part so as to satisfy the relationship of formula (1), it is possible to reduce the ratio of the thermal resistance at the connection part between the first transfer member 11 and the second transfer member 12 to the thermal resistance from the heat absorption surface 51 to the heat dissipation surface 52, and to smoothly transfer heat between the first transfer member 11 and the second transfer member 12. Therefore, the method of joining the first transfer member 11 and the second transfer member 12 is not limited, and various joining methods can be adopted.

[0025] According to the above configuration, the provision of the heat diffusion member 13 can prevent uneven temperature distribution on the heat absorption surface 51 and the heat dissipation surface 52. As a result, it is possible to reduce the thermal resistance on the heat transfer path from the heat source to the heat dissipation member 22 via the first transfer member 11 and the second transfer member 12, and the heat source can be cooled more efficiently. Therefore, it is possible to realize more stable operation of the circuit.

[0026] (Other embodiments) Although the embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not depart from the gist of the present disclosure are also included.

[0027] 9 as a first modified example, the second transfer member 12 may have a pair of second protruding portions 42, similar to the first transfer member 11. In this case, one of the second protruding portions 42 is sandwiched between the first protruding portions 32, and the other second protruding portion 42 is in contact with one of the first protruding portions 32 from the outside, and these are connected to each other.

[0028] According to the above configuration, a pair of second protrusions 42 are provided, and one of the first protrusions 32 is inserted between these second protrusions 42, thereby connecting the first transfer member 11 and the second transfer member 12. In other words, the contact area between the first protrusion 32 and the second protrusion 42 can be increased compared to when there is only one second protrusion 42. Therefore, heat can be transferred more efficiently and smoothly between the first transfer member 11 and the second transfer member 12. As a result, heat dissipation during the transfer process is minimized, and the cooling effect of the heat source can be further improved.

[0029] 10 as a second modified example, another second protrusion 42 may be formed on the end of the second transfer member 12 opposite to the end to which the first transfer member 11 is connected. In this case, it becomes possible to further connect another first transfer member 11 via the second protrusion 42 in a direction intersecting the second transfer member 12.

[0030] According to the above configuration, by connecting any number of first transfer members 11 and second transfer members 12, it is possible to adjust the length of the heat transfer path as desired. This makes it possible to effectively cool the heat source while improving the design freedom of the substrate 2. Therefore, it is no longer necessary to determine the circuit layout and wiring of the substrate 2 depending only on the heat dissipation path, and it becomes possible to design the substrate 2 with a focus on the stability of circuit operation.

[0031] Furthermore, in the above embodiment, an example has been described in which the first transport member 11 and the second transport member 12 are built into the inside of the substrate 2. However, the first transport member 11 and the second transport member 12 may be exposed on the front or back surface of the substrate 2. In this case, it is desirable to apply a coating of a metal film to protect the graphite from external forces, etc.

[0032] Furthermore, in the above embodiment, an example in which the first transfer member 11 and the second transfer member 12 extend in the same plane has been described. However, depending on the layout of the circuit and the board 2, it is possible to adopt a configuration in which these members are connected so as to be bent three-dimensionally. Specifically, it is possible to adopt a configuration as shown in FIG. 11 and FIG. 12. In this configuration, at least one of the first transfer member 11 and the second transfer member 12 extends three-dimensionally in the direction in which the first protruding portion 32 and the second protruding portion 42 overlap. Even in this case, the same effect as that described above can be obtained. In addition, the degree of freedom in designing the heat path is increased, and the heat transfer device 1 can be applied to various objects regardless of the shape and size of the object.

[0033] It is also possible to adopt a configuration further including a third transfer member having the same graphite lamination direction as the first transfer member, and a plurality of second transfer members joined to a midpoint in the extending direction of the third transfer member (see FIG. 13). With this configuration, it is possible to branch the heat transfer path from one third transfer member to a plurality of second transfer members.

[0034] Additionally, in the above embodiment, an example has been described in which the first transfer member 11 and the second transfer member 12 are connected so as to be perpendicular to each other. However, the manner in which the first transfer member 11 and the second transfer member 12 are connected is not limited to this, and it is also possible to adopt a manner in which these members intersect at an angle less than 90° or more than 90° (see FIG. 14). In either case, the same action and effect as described above can be obtained.

[0035] In the above embodiment, an example has been described in which one each of the first transfer members 11 and the second transfer members 12 are connected, or a total of three are connected. However, depending on the length of the heat transfer path, the number of these members may be four or more (see FIG. 15). In either case, the same effects as those described above can be obtained.

[0036] Furthermore, the material of the first transport member 11 and the second transport member 12 is not limited to graphite, and copper may also be used depending on the design and specifications.

[0037] Furthermore, it is also possible to adopt a configuration in which the first transfer member 11 or the second transfer member 12 extending from the multiple heat generating elements 21 join together and extend to one heat dissipation member 22. In addition, the heat dissipation member 22 may be attached to the front surface side of the substrate 2 (i.e., the side on which the heat generating elements 21 are mounted).

[0038] The joining method for the joints of the first conveying member 11 and the second conveying member 12 is preferably diffusion bonding. Alternatively, an adhesive (preferably a thermally conductive adhesive) may be used. They do not need to be firmly attached, but can be fitted together with grease applied.

[0039] The first transport member 11 and the second transport member 12 may be an integral member made of graphite, or may be formed into a plate shape by joining (laminating) thin graphite plates.

[0040] When the thickness of the second transfer member 12 is thinner than the thickness of the first transfer member 11, the protrusion 42 of the second transfer member 12 is not necessary, and the second transfer member 12 can simply be inserted into the recessed portion of the protrusion 32 of the first transfer member 11.

[0041] In addition, it is preferable that the total thickness of the protrusions 32 is equal to the total thickness of the protrusions 42. Note that the total thickness of the protrusions 32 and the total thickness of the protrusions 42 do not necessarily have to be equal, and it is sufficient that they are close to each other.

[0042] Furthermore, the application of the heat transfer device 1 is not limited to the circuit board 100, but instead of the board 2, the heat transfer device 1 can be applied to any object that requires heat transfer.

[0043] <Additional Notes> The heat-transfer device 1 according to each embodiment can be understood, for example, as follows.

[0044] (1) The heat transfer device 1 of the first embodiment is a heat transfer device 1 for transferring heat generated at a heat source toward a heat dissipation member 22, and comprises a first transfer member 11 having a heat absorption surface 51 in contact with the heat source and extending in one direction from the heat absorption surface, and a second transfer member 12 extending from a joint with the first transfer member 11 to the heat dissipation member 22 and having a heat dissipation surface 52 in contact with the heat dissipation member 22, wherein a pair of first protrusions 32 arranged at a distance from each other are formed on an end of the first transfer member 11, and a second protrusion 42 is formed on an end of the second transfer member 12 and inserted between the pair of first protrusions 32.

[0045] According to the above configuration, the second protruding portion 42 of the second transfer member 12 is fitted between the first protruding portions 32 of the first transfer member 11, thereby making it possible to increase the contact area between the first transfer member 11 and the second transfer member 12. This allows the first transfer member 11 and the second transfer member 12 to efficiently transfer heat toward the heat dissipation member 22 located away from the heat source.

[0046] (2) A heat transfer device 1 according to a second aspect is the heat transfer device 1 of (1), wherein the first transfer member 11 and the second transfer member 12 are plate-shaped and made of graphite, and in the graphite of the first transfer member 11, the stacking direction of multiple layers made of a crystalline structure is direction D2 perpendicular to both the extension direction (longitudinal direction) of the first transfer member 11 and the overlapping direction of the first protrusion 32 and the second protrusion 42, and in the graphite of the second transfer member 12, the stacking direction of multiple layers made of a crystalline structure is direction D1 perpendicular to both the extension direction (longitudinal direction) of the second transfer member 12 and the overlapping direction of the first protrusion 32 and the second protrusion 42.

[0047] Here, the thermal conductivity of graphite tends to be relatively high inside the layer made of a crystalline structure, but relatively low between the layers. According to the above configuration, the graphite of the first transfer member 11 maintains a high thermal conductivity in the direction from the heat absorption surface 51 toward the joint surface with the second transfer member, and the graphite of the second transfer member 12 maintains a high thermal conductivity in the direction from the joint surface with the first transfer member toward the heat dissipation surface 52. As a result, even if the first transfer member 11 and the second transfer member 12 are connected in a direction intersecting each other, it is possible to efficiently transfer heat toward the heat dissipation member 22 without dissipating heat to the surroundings. Therefore, the cooling effect on the heat source can be further improved.

[0048] (3) A heat transfer device 1 according to a third aspect is a heat transfer device 1 according to (1) or (2), wherein a pair of second protrusions 42 are formed at the end of the second transfer member 12, which sandwich one of the first protrusions 32 of the first transfer member 11 in the thickness direction.

[0049] According to the above configuration, a pair of second protruding portions 42 are provided, and one of the first protruding portions 32 is inserted between these second protruding portions 42, thereby connecting the first transfer member 11 and the second transfer member 12. In other words, compared to the case where there is only one second protruding portion 42, the contact area between the first protruding portion 32 and the second protruding portion 42 can be increased. Therefore, heat can be transferred between the first transfer member 11 and the second transfer member 12 more efficiently and smoothly.

[0050] (4) A heat transfer device 1 according to a fourth aspect is a heat transfer device 1 according to any one of aspects (1) to (3), in which the first transfer member 11 and the second transfer member 12 are embedded inside an object (substrate 2).

[0051] According to the above configuration, the first transport member 11 and the second transport member 12 are embedded inside the object, that is, the substrate 2, and therefore these members can be protected from external shocks and vibrations. This is particularly advantageous when the first transport member 11 and the second transport member 12 are made of a brittle material such as graphite.

[0052] (5) A heat transfer device 1 in a fifth aspect is a heat transfer device 1 in any one of the aspects (1) to (4), further comprising: another second protrusion 42 formed on the end of the second transfer member 12 opposite the end to which the first transfer member 11 is connected; and further comprising another first transfer member 11 connected in a direction intersecting the second transfer member 12 via the second protrusion 42.

[0053] According to the above configuration, it is possible to arbitrarily adjust the length of the heat transfer path by connecting any number of first transfer members 11 and second transfer members 12. This makes it possible to effectively cool the heat source while improving the degree of freedom in designing the object.

[0054] (6) The heat transfer device 1 of the sixth aspect is the heat transfer device 1 of (2), further comprising a third transfer member 11a having the same graphite stacking direction as the first transfer member 11, and a plurality of second transfer members 12 joined to a midpoint in the extension direction of the third transfer member 11a.

[0055] According to the above configuration, the heat transfer path can be branched from one third transfer member 11a to a plurality of second transfer members 12.

[0056] (7) The heat transfer device 1 of the seventh aspect is the heat transfer device 1 of (2), wherein at least one of the first transfer member 11 and the second transfer member 12 extends three-dimensionally in the direction in which the first protrusion 32 and the second protrusion 42 overlap.

[0057] According to the above configuration, the degree of freedom in designing the heat path is increased, and the heat transfer device 1 can be applied to a variety of objects regardless of the shape or size of the object.

[0058] (8) The heat transfer device 1 of the eighth aspect is a heat transfer device 1 of any one of the aspects (1) to (5), further comprising a heat diffusion member 13 provided between the heat source and the object, and between the heat dissipation member 22 and the object, respectively.

[0059] According to the above configuration, the provision of the thermal diffusion member 13 can prevent uneven temperature distribution on the heat absorption surface 51 and the heat dissipation surface 52. As a result, it is possible to reduce the thermal resistance on the heat transfer path from the heat source to the heat dissipation member 22 via the first transfer member 11 and the second transfer member 12, and the heat source can be cooled more efficiently.

[0060] (9) A circuit board 100 according to a ninth aspect includes a heat transfer device 1 as in (1) or (2), and a substrate 2 on which the heat transfer device 1, a heat generating element 21 as the heat source, and a heat sink as the heat dissipation member 22 are provided.

[0061] According to the above configuration, it is possible to provide a circuit board 100 in which the heat transfer path can be freely set.

[0062] (10) The circuit board 100 according to the tenth aspect is the circuit board 100 of (9), wherein the heat transfer device 1 is arranged to extend to the heat dissipation member 22, bypassing other elements that have a lower heat resistance than the heat source.

[0063] According to the above configuration, the heat from the heat source can be transferred to the heat dissipation member 22 by the heat transfer device 1 without affecting other elements with low heat resistance. [Explanation of symbols]

[0064] 1...heat transfer device 2...substrate 11...first transfer member 12...second transfer member 11a...third transfer member 13...heat diffusion member 21...heat generating element 22...heat dissipation member 23...other element 31...first main body 32...first protrusion 41...second main body 42...second protrusion 51...heat absorption surface 52...heat dissipation surface D1...direction perpendicular to both the extension direction (longitudinal direction) of the second transfer member 12 and the direction in which the first protrusion 32 and the second protrusion 42 overlap D2...direction perpendicular to both the extension direction (longitudinal direction) of the first transfer member 11 and the direction in which the first protrusion 32 and the second protrusion 42 overlap 100...circuit board

Claims

1. A heat transfer device for transferring heat generated by a heat source to a heat dissipation member, a first conveying member having a heat absorbing surface in contact with the heat source and extending in one direction from the heat absorbing surface; a second conveying member extending from a joint with the first conveying member to the heat dissipating member and having a heat dissipating surface in contact with the heat dissipating member; Equipped with A heat transfer device in which a pair of first protrusions is formed on an end of the first transfer member, and a second protrusion is formed on an end of the second transfer member, the second protrusion being inserted between the pair of first protrusions.

2. The first conveying member and the second conveying member are plate-shaped and made of graphite. In the graphite of the first transport member, a stacking direction of a plurality of layers having a crystal structure is a direction perpendicular to both a direction in which the first transport member extends and a direction in which the first protruding portion and the second protruding portion overlap each other, The heat transfer device described in claim 1, wherein the stacking direction of multiple layers of crystalline structure in the graphite of the second transfer member is perpendicular to both the extension direction of the second transfer member and the overlapping direction of the first protrusion and the second protrusion.

3. The heat transfer device according to claim 1 or 2, wherein an end of the second transfer member is provided with a pair of second protrusions that sandwich one of the first protrusions of the first transfer member in the thickness direction.

4. The heat-transfer device of claim 1 , wherein the first transfer member and the second transfer member are embedded within an object.

5. The heat transfer device described in claim 1, further comprising: another second protrusion formed on an end of the second transfer member opposite to the end to which the first transfer member is connected; and another first transfer member connected in a direction intersecting the second transfer member via the second protrusion.

6. a third conveying member having the same stacking direction of the graphite as that of the first conveying member; 3. The heat transfer device according to claim 2, further comprising a plurality of second members joined to the third transfer member at intermediate positions in the extending direction of the third transfer member.

7. The heat transfer device according to claim 2 , wherein at least one of the first transfer member and the second transfer member extends three-dimensionally in a direction in which the first protrusion and the second protrusion overlap.

8. The heat transfer device according to claim 1 or 2, further comprising a heat diffusion member provided between the heat source and the object, and between the heat dissipation member and the object, respectively.

9. A heat transfer device according to claim 1 or 2; a substrate on which the heat transfer device, a heat generating element as the heat source, and a heat sink as the heat dissipation member are provided; A circuit board comprising:

10. 10. The circuit board according to claim 9, wherein the heat transfer device is disposed so as to extend to the heat dissipation member 22 while bypassing other elements having a lower heat resistance than the heat source.

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