Cooling structure and electronic device

Abstract

To provide a cooling structure that can efficiently cool a heating element placed on a substrate at low cost while avoiding interference with the surroundings, and can also support efficient cooling of a plurality of heating elements, and an electronic device using the same.SOLUTION: A cooling structure includes: a substrate 1 on which a heating element 3 that generates heat is placed; a heat radiating unit 2 that is arranged facing the substrate 1 and dissipates the heat generated by the heating element 3 to the outside; and a plurality of heat transfer blocks 5 that conduct the heat generated by the heating element 3 toward the heat radiating unit 2. The heat transfer blocks 5 are laminated with each other in a direction orthogonal to the substrate 1 and are arranged between the heating element 3 and the heat radiating unit 2. In an electronic device, the heat transfer blocks 5 are laminated with each other in the direction orthogonal to the substrate 1 and arranged between the electronic component and the heat radiating unit 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cooling structure for cooling a heat generating body such as an electronic component arranged on a substrate, and to an electronic device using the same. [Background technology]

[0002] Many electronic devices have electronic circuits in which electronic components are mounted on a printed wiring board (PWB). Electronic components such as integrated circuits, transistors, diodes, resistors, and capacitors are soldered onto the PWB, which has wiring formed by lithography, to form a printed circuit board (PCB). Some electronic components generate heat during operation, so they are used with a cooling structure to dissipate the heat.

[0003] Heat sinks, heat pipes, etc. are often used as cooling structures. In addition, because heat dissipation to the board is insufficient for cooling, a method is also used in which the housing that houses the electronic components is used for heat dissipation. In general, heat dissipation parts such as heat sinks and housings that dissipate heat generated by electronic components to the outside are attached to each heat-generating component such as an integrated circuit via a heat dissipation member such as a metal plate or metal block.

[0004] In recent years, the amount of information processed by electronic devices has increased, and the amount of heat generated by electronic components has also tended to increase. Therefore, there is a demand for a cooling structure that can efficiently cool electronic components. Since a heat dissipation member that thermally connects an electronic component to a heat dissipation unit has a problem of interference with other electronic components, improvements to the cooling structure have been considered.

[0005] Patent Document 1 describes a sealed electronic device that includes a heat-generating component, a housing, and a heat-dissipating member (heat-dissipating section). The heat-dissipating member is formed so that its contact area with the housing is larger than its contact area with the heat-generating component. The side of the heat-dissipating member is a tapered section that is gradually widened from the heat-generating component to the housing and formed in a tapered shape. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2009-152362 A Summary of the Invention [Problem to be solved by the invention]

[0007] Conventionally, a heat dissipation unit that dissipates heat generated by an electronic component to the outside has been attached to the heat-generating component via a heat dissipation member such as a metal plate or metal block, but a rectangular heat dissipation member has a problem in that it is likely to interfere with other electronic components arranged around the heat-generating component. When it interferes with other electronic components, the size of the heat dissipation member cannot be increased, and the cross-sectional area of ​​the heat transfer path cannot be increased, making it difficult to dissipate heat sufficiently.

[0008] As described in Patent Document 1, by providing a heat dissipation member in a tapered shape, it is possible to avoid interference with other electronic components while ensuring the cross-sectional area of ​​the heat transfer path. However, when providing a heat dissipation member in a tapered shape, there is a problem that the processing cost increases. Copper described in Patent Document 1 is difficult to cut, so it is difficult to realize a low-cost cooling structure.

[0009] In addition, not only integrated circuits that generate heat, but also other tall electronic components may be mounted on a printed circuit board. If such electronic components do not generate heat, there is no need to contact the heat dissipation member, but there is a risk that interference cannot be avoided by providing a tapered heat dissipation member. In such cases, the circuit layout may be restricted or the board may need to be made larger. In particular, in the case of integrated circuits that consume more than 10 W of power, a heat transfer member that covers most of the circuit board is required, and interference between components becomes a major problem.

[0010] In addition, multiple heat-generating components to be cooled may be arranged closely together on a printed circuit board. In general, it is said that a heat transfer path that spreads outward in a vertically upward direction is preferable. However, when the heat dissipation member is provided in a tapered shape, it is difficult to ensure such a heat transfer path for each heat-generating component.

[0011] Therefore, the present invention aims to provide a cooling structure that is capable of efficiently cooling heat-generating elements arranged on a substrate at low cost while avoiding interference with the surrounding area, and that can also efficiently cool multiple heat-generating elements, and an electronic device using the same. [Means for solving the problem]

[0012] That is, in order to solve the above problems, the cooling structure according to the present invention includes a substrate on which a heat generating element is disposed, a heat dissipation section disposed opposite the substrate and dissipating the heat generated by the heat generating element to the outside, a plurality of heat transfer blocks for thermally conducting the heat generated by the heat generating element toward the heat dissipation section, and a heat transfer elastic body having elasticity for thermally conducting the heat generated by the heat generating element toward the heat dissipation section, wherein the heat transfer blocks are: Each of the electrodes is provided as a columnar body, which may be a rectangular parallelepiped, a cube, a rhomboidal column, or a cylindrical column; The heat transfer elastic body is disposed between the heat transfer block and the heat dissipation portion, and is stacked on top of each other in a direction perpendicular to the substrate. The heat transfer elastic body is disposed between the heat transfer block and the heat dissipation portion.

[0013] Further, an electronic device according to the present invention includes a substrate on which electronic components are arranged, a heat dissipation section arranged opposite the substrate and dissipating heat generated by the electronic components to the outside, a plurality of heat transfer blocks for thermally conducting the heat generated by the electronic components toward the heat dissipation section, and a heat transfer elastic body having elasticity for thermally conducting the heat generated by the electronic components toward the heat dissipation section, wherein the heat transfer blocks are: Each of the electrodes is provided as a columnar body, which may be a rectangular parallelepiped, a cube, a rhomboidal column, or a cylindrical column; The heat transfer elastomer is stacked on top of each other in a direction perpendicular to the substrate and disposed between the electronic component and the heat dissipation portion, and the heat transfer elastomer is provided with a cooling structure disposed between the heat transfer block and the heat dissipation portion. Effect of the Invention

[0014] According to the present invention, it is possible to provide a cooling structure that is capable of efficiently cooling a heat generating element arranged on a substrate at low cost while avoiding interference with the surroundings, and that can also efficiently cool multiple heat generating elements, as well as electronic equipment using the same. [Brief description of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view of a printed circuit board illustrating an example of a cooling structure according to an embodiment of the present invention. [Diagram 2] 1 is a cross-sectional view of a printed circuit board showing a cooling structure according to a comparative example. [Diagram 3] 1 is a cross-sectional view of a printed circuit board illustrating an example of a cooling structure according to an embodiment of the present invention. [Figure 4] 1 is a cross-sectional view of a printed circuit board illustrating an example of a cooling structure according to an embodiment of the present invention. [Diagram 5] 1 is a diagram showing a cooling structure according to a first embodiment of the present invention. [Figure 6] FIG. 4 is a diagram showing a cooling structure according to a first comparative example. [Figure 7] FIG. 11 is a diagram showing a cooling structure according to Comparative Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, a cooling structure according to an embodiment of the present invention and an electronic device using the same will be described with reference to the drawings. In the following drawings, the same reference numerals will be used to designate common components, and duplicated descriptions will be omitted.

[0017] FIG. 1 is a cross-sectional view of a printed circuit board showing an example of a cooling structure according to an embodiment of the present invention. As shown in FIG. 1, the cooling structure of this embodiment includes a substrate 1, a housing 2 that houses the substrate 1, electronic components 3 and 4 arranged on the substrate 1, and heat dissipation members 5 and 6 that conduct heat generated by the electronic components toward the housing 2.

[0018] In the cooling structure shown in FIG. 1, the electronic components 3 and 4 are arranged on a substrate 1, and include a heat-generating component 3 that generates heat requiring cooling during operation and is therefore subject to cooling, and a non-cooled component 4 that does not substantially generate heat requiring cooling and is therefore not subject to cooling.

[0019] In addition, in the cooling structure shown in Figure 1, the heat dissipation members 5, 6 are a heat transfer block 5 of a simple shape made of a material with high thermal conductivity, and a thin-layer heat transfer material 6 made of a material with high thermal conductivity, which are arranged between the heat-generating component 3 and the housing 2.

[0020] The housing 2 has a hollow structure, and its ceiling surface is disposed opposite the substrate 1. In the cooling structure shown in Fig. 1, the housing 2 functions as a heat dissipation section that dissipates heat generated by the heat-generating component 3 to the outside.

[0021] Fig. 1 shows a printed circuit board on which a heat-generating component 3 is arranged, as an example of a cooling structure for cooling a heat-generating body arranged on a board. The cooling structure shown in Fig. 1 is structured so that heat generated by the heat-generating component (heat-generating body) 3, which is an electronic component, is transferred to a housing 2 via heat dissipation members 5 and 6, and dissipated from the housing 2 to the outside.

[0022] 1, the heat transfer path to the housing 2, which functions as a heat dissipation section, is formed by a heat transfer block 5 and a heat transfer material 6. The main feature of the cooling structure shown in FIG. 1 is that the heat transfer blocks 5, each having a simple shape, are stacked on top of each other in a direction perpendicular to the heat-generating component 3, i.e., in a direction perpendicular to the substrate 1.

[0023] Substrate 1 is a printed wiring board on which wiring is formed, and electronic components 3 and 4 are soldered to its surface. A printed wiring board is obtained, for example, by impregnating an insulating material such as paper or glass with a resin such as epoxy resin or bakelite, and patterning predetermined wiring by lithography.

[0024] In addition to the substrate 1, the housing 2 also houses electronic components 3 and 4 and heat dissipation members 5 and 6. In the cooling structure shown in Fig. 1, the housing 2 functions as a heat dissipation section that dissipates heat generated by the heat-generating component 3 to the outside, but from the viewpoint of more efficient heat dissipation, it is also possible to thermally connect another heat dissipation mechanism to the housing 2. Examples of other heat dissipation mechanisms include a ventilation fan and a heat sink structure.

[0025] The heat-generating component 3 is an electronic component that generates heat that requires cooling during operation, and is the target of cooling using the heat dissipation members 5, 6. The heat-generating component 3 is in contact with the heat dissipation members 5, 6, and is thermally connected to the housing 2 via the heat dissipation members 5, 6. The type, number, size, and height of the heat-generating component 3 are not particularly limited, as long as it generates heat that requires cooling. Specific examples of the heat-generating component 3 include integrated circuits such as LSIs (Large Scale Integrated circuits).

[0026] The non-cooled components 4 are electronic components that do not substantially generate heat that requires cooling. The non-cooled components 4 are non-heat generating bodies that are not the subject of cooling using the heat dissipation members 5 and 6, and therefore do not need to be thermally connected to the housing 2. The type, number, size, and height of the non-cooled components 4 are not particularly limited.

[0027] 1, on a substrate 1, tall components (tall bodies) that are taller than a heat-generating component 3 are arranged as non-cooled components 4 around the heat-generating component 3. Heat dissipation members 5 and 6 are thermally connected to the heat-generating component 3 and the housing 2, but need to be arranged so as not to interfere with such tall components. A specific example of a tall component is a capacitor.

[0028] The heat transfer block 5 is a member for conducting heat generated by the heat generating component 3, which is a heat generating body, toward the heat dissipation section, and is formed in a block shape from a material with high thermal conductivity. A plurality of heat transfer blocks 5 are arranged between the heat generating component 3 and the housing 2. The plurality of heat transfer blocks 5 are stacked on top of each other in a direction perpendicular to the main surface of the heat generating component 3, i.e., along the normal direction perpendicular to the substrate 1.

[0029] The heat transfer material 6 is a member for conducting heat generated by the heat generating component 3, which is a heat generating body, toward the heat dissipation section, and is formed in a thin layer using a material with high thermal conductivity. The heat transfer material 6 is disposed between the substrate 1 and the housing 2, between the heat transfer blocks 5, between the heat transfer block 5 and the substrate 1, and between the heat transfer block 5 and the housing 2.

[0030] As the heat transfer material 6, a heat transfer sheet in which a material with high thermal conductivity is formed into a sheet, a heat transfer grease in which a material with high thermal conductivity is mixed with a lubricant such as silicone, a heat transfer paste in which a material with high thermal conductivity is mixed with a binder, etc., or other heat conductive materials can be used. One type of heat transfer material 6 may be used between each member, or multiple types may be used in combination.

[0031] FIG. 2 is a cross-sectional view of a printed circuit board showing a cooling structure according to a comparative example. 2, a conventional general cooling structure (comparative example) includes a substrate 1, a housing 2, and electronic components 3 and 4, similar to the cooling structure shown in Fig. 1. However, the conventional general cooling structure differs from the cooling structure shown in Fig. 1 in the configuration of heat dissipation members 51 and 61.

[0032] 2, as the electronic components 3 and 4, a heat-generating component 3 and a non-cooled component 4 are arranged on the substrate 1. As the heat dissipation members 51 and 61, a heat transfer block 51 made of a material with high thermal conductivity and a thin-layer heat transfer material 61 made of a material with high thermal conductivity are arranged between the heat-generating component 3 and the housing 2.

[0033] 2, a single heat transfer block 51 provided in a rectangular parallelepiped shape is used as a heat dissipation member that thermally connects the heat-generating component 3 and the housing 2. Conventional general cooling structures do not have a structure in which a plurality of heat transfer blocks 51 are stacked on top of each other. In such a cooling structure, as shown by the arrow in FIG. 2, the diffusion of heat by thermal conduction proceeds only in approximately one direction perpendicular to the substrate 1.

[0034] 2, it is difficult to realize a large amount of heat dissipation under a certain heat flux because the cross-sectional area of ​​the heat transfer path is determined by the cross-sectional area of ​​one heat transfer block 51. If one heat transfer block 51 is provided in a tapered shape as in Patent Document 1, the cross-sectional area of ​​the heat transfer path increases toward the housing 2 side, but this increases the processing cost and may cause interference with tall parts when they are arranged around the heat-generating part 3.

[0035] In contrast, the cooling structure shown in FIG. 1 has a structure in which multiple heat transfer blocks 5 are stacked, so that when a small heat transfer block 5 is used at the height of a tall component and a large heat transfer block 5 is used above it, a heat transfer path with a sufficiently expanded cross-sectional area is formed without interfering with the tall component. As a result, unlike the case of using a single conventional heat dissipation member, a part of the stacked heat transfer blocks 5 with a simple shape is positioned above the tall component. With this structure, as shown by the arrows in FIG. 1, heat is diffused by thermal conduction not only in the direction perpendicular to the substrate 1 but also in the direction parallel to the substrate 1. Therefore, the cross-sectional area of ​​the heat transfer path can be expanded while avoiding interference with the tall component, thereby enabling efficient heat dissipation.

[0036] Note that the heat transfer blocks 5 may be stacked in other directions as long as they are stacked at least in a direction perpendicular to the substrate 1 for each heat-generating component 3 to be cooled. For example, in addition to the heat transfer blocks 5 stacked vertically, another heat transfer block 5 may be stacked in a direction parallel to the substrate 1, such as front-back or left-right (front, back, left, right, etc. in FIG. 1).

[0037] 1, the heat transfer blocks 5 are preferably stacked such that the cross-sectional area of ​​the heat transfer blocks 5 increases from the heat generating component 3 toward the housing 2. In addition, the heat transfer blocks 5 are preferably arranged such that the contact areas between the members have a similar relationship. That is, the heat transfer blocks 5 may have a cross-sectional area equal to that of the heat generating component 3, and a cross-sectional area larger than that of the heat generating component 3. In this case, the heat transfer blocks 5 are preferably stacked such that the cross-sectional area of ​​the heat transfer blocks 5 and the contact areas between the members increase toward the housing 2.

[0038] According to the structure in which the cross-sectional area of ​​the heat transfer block 5 and the contact area between the components increase closer to the housing 2, even if the heat transfer block 5 on the heat generating component 3 side is made smaller, the cross-sectional area of ​​the heat transfer path always increases closer to the housing 2 side. Therefore, it is possible to dissipate heat efficiently while avoiding interference with tall components. Since the area on the housing 2 side is occupied by the heat transfer block 5, not by space, it is possible to ensure the amount of heat dissipation by solid thermal conduction.

[0039] The heat transfer block 5 is preferably provided as a columnar body. The columnar body means a solid body whose upper and lower surfaces are parallel to each other and have similar shapes. Specific examples of the columnar body include a rectangular parallelepiped, a cube, a rhombic column, and a cylinder. The heat transfer block 5 is preferably composed of only a columnar body, and is particularly preferably composed of only a rectangular parallelepiped or a cube.

[0040] Making the heat transfer block 5 into a columnar body facilitates processing and manufacturing, thereby reducing the cost of the heat transfer block 5. Since the columnar body has a simple shape, extrusion material, forging material, ingot, etc. can be used as the heat transfer block 5 without significant secondary processing after cutting. Since there is no need to perform secondary processing into a complex shape by cutting or the like to avoid interference with tall parts, an efficient cooling structure can be realized at low cost.

[0041] Furthermore, when the heat transfer block 5 is a columnar body, the components are more likely to come into contact with each other when stacked on the heat-generating component 3. This makes it easier to form a heat transfer path with high heat dissipation efficiency. Furthermore, when the heat transfer block 5 is a columnar body, the cross-sectional area of ​​the heat transfer path is expanded simply by increasing the size of the heat transfer block 5, so that a cooling structure with high heat dissipation efficiency can be obtained.

[0042] The heat transfer block 5 is preferably made of a metal with high thermal conductivity such as aluminum, copper, or silver, and is particularly preferably made of an aluminum alloy. Aluminum alloys provide high thermal conductivity as well as high mechanical strength and workability. This provides a stable structure, and allows for a low-cost and efficient cooling structure.

[0043] When the heat transfer block 5 is made of an aluminum alloy, it is preferable to subject it to anodizing treatment. In general, copper is an example of a material that is excellent in thermal conductivity, strength, corrosion resistance, and the like. However, copper may corrode in the presence of sulfur components such as hydrogen sulfide or in an oxidizing environment. In contrast, anodizing treatment provides an aluminum block with an anodized film on its surface that is excellent in corrosion resistance, and therefore provides a cooling structure that is more resistant to corrosion than copper.

[0044] It is preferable to use at least a heat transfer elastomer having elasticity as the heat transfer material 6. The heat transfer elastomer may be disposed in one or more of between the heat transfer blocks 5, between the heat transfer block 5 and the substrate 1, and between the heat transfer block 5 and the housing 2. As the heat transfer elastomer, a heat transfer sheet, a heat transfer paste, or the like having elasticity to the extent that it is deformed by the weight of the heat transfer block 5 at room temperature can be used.

[0045] By disposing the heat transfer elastic body in at least one location, even if there is a possibility that gaps will occur between the heat transfer blocks 5, between the heat transfer block 5 and the substrate 1, or between the heat transfer block 5 and the housing 2 due to dimensional errors, assembly, impact, vibration, etc., it is possible to eliminate the gaps through elastic deformation. Therefore, even in a structure in which multiple heat transfer blocks 5 are stacked, which is disadvantageous in terms of ensuring a heat transfer path, it is possible to efficiently dissipate heat.

[0046] Any suitable method can be used to fix the stacked heat transfer blocks 5. The heat transfer blocks 5 can be joined to each other using, for example, screws, bolts and nuts, brackets, corner braces, adhesives, etc., between the heat transfer blocks 5 themselves, between the heat transfer blocks 5 and the substrate 1, and between the heat transfer blocks 5 and the housing 2. These joining methods do not require significant secondary processing of the heat transfer blocks 5 themselves, and therefore the cooling structure can be realized at low cost.

[0047] 1, the housing 2 is of a sealed type, but may be of a non-sealed type. The housing 2 may be provided in any suitable shape or structure as long as the portion facing the substrate 1 serves as a heat transfer path. Heat dissipation through the housing 2 may involve heat radiation, natural convection heat transfer, forced convection heat transfer, etc., in addition to heat conduction through the heat dissipation members 5 and 6.

[0048] 1, the wiring and electronic components 3, 4 are provided on the upper surface of the substrate 1, and the heat dissipation members 5, 6 are arranged facing the ceiling of the housing 2, but the direction of the heat transfer path is not particularly limited. The wiring and electronic components 3, 4 may be provided on the lower surface of the substrate 1, and the heat dissipation members 5, 6 may be arranged facing the bottom of the housing 2.

[0049] 1, the wiring and electronic components 3 and 4 are provided on one side of the substrate 1, but they may be provided on both sides of the substrate 1. When the wiring and electronic components 3 and 4 are provided on both sides of the substrate 1, the heat dissipation members 5 and 6 may be disposed on both sides of the substrate 1, or may be disposed on one side of the substrate 1 where a heat transfer path to both sides is secured.

[0050] FIG. 3 is a cross-sectional view of a printed circuit board showing an example of a cooling structure according to an embodiment of the present invention. 3, a cooling structure in which a plurality of heat transfer blocks 5 are stacked can also be formed for a plurality of heat-generating components 3. The cooling structure according to this embodiment includes a substrate 1, a housing 2, electronic components 3 and 4, and heat dissipation members 5 and 6, similar to the cooling structure shown in FIG.

[0051] 3, a plurality of heat generating components 3 and a non-cooled component 4, each having a different height, are arranged on the substrate 1 as the electronic components 3 and 4. A plurality of heat transfer blocks 5 made of a material with high thermal conductivity and a thin-layer heat transfer material 6 made of a material with high thermal conductivity are arranged between the heat generating components 3 and the housing 2 as the heat dissipation members 5 and 6.

[0052] 3, among the multiple heat transfer blocks 5 stacked on top of each other, some of the heat transfer blocks 5 can be thermally connected to each of the multiple heat-generating components 3. The number of heat-generating components 3 thermally connected to one heat transfer block 5 may be two or more. Furthermore, the type, size, and height of the heat-generating components 3 thermally connected to one heat transfer block 5 are not particularly limited.

[0053] As shown in Fig. 3, the heat transfer blocks 5 are preferably stacked such that the total cross-sectional area of ​​the heat transfer blocks 5 at the same height increases from the heat generating component 3 toward the housing 2. Also, it is preferable that the heat transfer blocks 5 are arranged so that the contact areas between the components have a similar relationship. That is, the heat transfer blocks 5 may have a cross-sectional area equal to that of the heat generating component 3 and a cross-sectional area larger than the total area of ​​the heat generating components 3. In this case, it is preferable to stack the heat transfer blocks 5 such that the cross-sectional area of ​​the heat transfer blocks 5 and the contact areas between the components increase toward the housing 2.

[0054] According to the cooling structure shown in Fig. 3, one heat transfer block 5 forms a heat transfer path for multiple heat-generating components 3, so that it is possible to reduce the space on the housing 2 side where the heat transfer block 5 is not present and increase the cross-sectional area of ​​the heat transfer path by solid thermal conduction. In Fig. 3, a tall component is placed between the heat-generating components 3, and the heights of the heat-generating components 3 are different from each other. However, even in such a case, since the structure is such that multiple heat transfer blocks 5 are stacked, it is possible to ensure a heat transfer path for each heat-generating component 3 without using blocks with complex shapes.

[0055] FIG. 4 is a cross-sectional view of a printed circuit board showing an example of a cooling structure according to an embodiment of the present invention. 4, the cooling structure in which a plurality of heat transfer blocks 5 are stacked can also be a stacked structure of three or more stages. The cooling structure according to this embodiment includes a substrate 1, a housing 2, electronic components 3 and 4, and heat dissipation members 5 and 6, similar to the cooling structure shown in FIG.

[0056] 4, the electronic components 3, 4 include a heat-generating component 3 and multiple tall components (non-cooled components 4) having different heights, which are arranged on the substrate 1. The heat-dissipating members 5, 6 include multiple heat-transfer blocks 5 made of a material with high thermal conductivity and a thin-layer heat-transfer material 6 made of a material with high thermal conductivity, which are arranged between the heat-generating component 3 and the housing 2.

[0057] In the cooling structure shown in Fig. 4, multiple tall components that are taller than the heat-generating component 3 are arranged on the substrate 1 around the heat-generating component 3. The tall components have different heights, and the further away from the heat-generating component 3, the taller they are. In such a structure, when a single conventional heat dissipation member is used, it is not possible to avoid interference with the multiple tall components individually, so it is necessary to make the heat dissipation member have a complex shape at the expense of processing costs or to sacrifice the cross-sectional area of ​​the heat transfer path.

[0058] However, according to the cooling structure shown in Fig. 4, since multiple heat transfer blocks 5 are stacked, when a stacked structure of three or more layers is used, a heat transfer path with a sufficiently expanded cross-sectional area is formed without interference with multiple tall components. As a result, unlike the case where a single heat dissipation member is used in the past, a part of the stacked heat transfer blocks 5 of a simple shape is located above the multiple tall components. According to such a structure, the number and size of the heat transfer blocks 5 of a simple shape can be adjusted to correspond to the number and height of various tall components, so that it is possible to avoid interference with tall components and ensure the cross-sectional area of ​​the heat transfer path at the same time.

[0059] 4, the heat transfer blocks 5 are preferably stacked such that the contact surface that comes into contact with the member on the housing 2 (heat dissipation section) side spreads outward at a predetermined angle (θ shown in FIG. 4) or more than the contact surface that comes into contact with the member on the heat generating component 3 side. That is, the heat transfer blocks 5 and heat transfer material 6 arranged on the upper side are preferably stacked such that the outer end (upper edge of the side) of the upper surface of the heat transfer block 5, heat transfer material 6, and heat generating component 3 arranged on the lower side spreads outward at a predetermined angle (θ) or more with respect to the normal to the heat generating component 3, starting from the outer end (upper edge of the side) of the upper surface of the heat transfer block 5, heat transfer material 6, and heat generating component 3 arranged on the lower side.

[0060] The angle (θ) is preferably 30 degrees or more, more preferably 35 degrees or more, even more preferably 40 degrees or more, even more preferably 45 degrees or more, even more preferably 50 degrees or more, even more preferably 55 degrees or more, even more preferably 60 degrees or more. With such an angle, the heat transfer path by solid heat conduction is expanded along the direction of thermal diffusion, allowing efficient heat dissipation.

[0061] It is preferable that the spread of such an angle (θ) is satisfied in at least one direction parallel to the substrate 1, for example, either the front-back or left-right directions (the front, back, left and right directions in FIG. 4), and it is more preferable that the spread is satisfied in all directions parallel to the substrate 1, that is, in all directions around the normal to the substrate 1. However, when an aluminum alloy or the like having high thermal conductivity is used, a cooling effect can be obtained by uniform heating, so the structure is not limited to this.

[0062] According to the cooling structure of the above embodiment, since the heat transfer blocks are stacked and blocks of simple shapes are used as the heat transfer blocks, a heat dissipation member that forms an appropriate heat transfer path can be provided at low cost. The heat transfer blocks are provided in advance in various sizes and heights, and can be rearranged as appropriate depending on the arrangement of the heat generating body and the tall body. In addition, they can be replaced as appropriate depending on the state of the heat generating body and the board. Therefore, the heat generating body arranged on the board can be efficiently cooled at low cost while avoiding interference with the surroundings. Even if multiple heat generating bodies are arranged on the board with a tall body between them or multiple heat generating bodies are at different heights, the multiple heat generating bodies can be efficiently cooled.

[0063] The cooling structure according to the above embodiment can be used for a printed circuit board having heat-generating components such as integrated circuits to provide an electronic device having a cooling structure in which a plurality of heat transfer blocks are stacked. When an aluminum block made of an aluminum alloy is used as the heat transfer block, this is particularly effective for electronic devices that are exposed to an atmosphere containing sulfur components and oxidizing substances.

[0064] Specific examples of electronic devices include industrial electronic devices such as control devices, power supplies, communication devices, display devices, monitoring devices, and measuring devices, as well as personal computers, portable personal computers, mobile phones, smartphones, personal digital assistants, televisions, displays, recorders, digital cameras, video cameras, audio equipment, refrigeration and air conditioners, washing machines, and vacuum cleaners.

[0065] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are included without departing from the technical scope. For example, the above-described embodiments are not necessarily limited to those having all the configurations described. It is also possible to replace a part of the configuration of an embodiment with another configuration, or to add another configuration to the configuration of an embodiment. It is also possible to add another configuration to, delete a configuration, or replace a configuration with respect to a part of the configuration of an embodiment. EXAMPLES

[0066] The present invention will be specifically described below with reference to examples, but the technical scope of the present invention is not limited to these examples.

[0067] The cooling performance of the cooling structures (Example 1, Comparative Example 1, and Comparative Example 2) in which a plurality of heat transfer blocks are stacked was evaluated by thermal fluid analysis.

[0068] Fig. 5 is a diagram showing a cooling structure according to Example 1 of the present invention, Fig. 6 is a diagram showing a cooling structure according to Comparative Example 1, Fig. 7 is a diagram showing a cooling structure according to Comparative Example 2. Using the structures shown in Figs. 5, 6 and 7 as calculation systems, thermal fluid analysis was performed using the finite volume method, and the temperature of the heat-generating component 3 was evaluated as the cooling performance.

[0069] Fig. 5 shows a cooling structure according to Example 1 in which a plurality of heat transfer blocks 5 are stacked on one another. Fig. 6 shows a cooling structure according to Comparative Example 1 in which one heat transfer block 5 provided in a rectangular parallelepiped shape is used, and a plurality of heat transfer blocks 5 are not stacked on one another. Fig. 7 shows a cooling structure according to Comparative Example 2 in which one heat transfer block 5 provided in the same shape as in Example 1 is used, and a plurality of heat transfer blocks 5 are not stacked on one another.

[0070] In Example 1 shown in FIG. 5, two rectangular parallelepiped heating elements were set as the heating component 3. On each heating element (3), a rectangular parallelepiped block was individually stacked as a heat transfer block 5, and a common rectangular parallelepiped block (5) was stacked thereon so as to be thermally connected to each of the two heating elements (3), and this was brought into contact with the structure as the housing 2. Between the heating elements (3), a rectangular parallelepiped tall structure was placed as a tall component (non-cooled component 4) that was shorter than the lower block (5) and taller than the heating elements. Between each member, a sheet simulating a thermally conductive sheet was placed as a heat transfer material 6.

[0071] As shown in Fig. 5, the distance between the top surface of the tall structure (4) and the bottom surface of the upper block (5) was 10 mm. In addition, the distance between the heating element (3) and the side surface of the tall structure (4) was 5 mm.

[0072] Additionally, on the inside between the two heating elements (3), the left and right positions of the heating element (3) and the lower block (5) were aligned so that the side of the heating element (3) was flush with the side of the lower block (5). On the other hand, on the outside, the outer ends (upper edges of the outer side faces) of the upper faces of the lower block (5) and the upper block (5) were shaped to extend 45 degrees outward from the outer end (upper edge of the outer side faces) of the surface of the heating element (3) with the outer end (upper edge of the outer side faces) of the heating element (3) as the starting point.

[0073] In Comparative Example 1 shown in Fig. 6, similar to the structure shown in Fig. 5, two rectangular parallelepiped heating elements were set as the heating component 3. A single rectangular parallelepiped block (5) was individually stacked on each heating element (3) as the heat transfer block 5, and these were brought into contact with the structure as the housing 2. A tall structure (4) similar to the structure shown in Fig. 5 was placed between the heating elements (3). A sheet simulating a heat conductive sheet was placed as the heat transfer material 6 between each member.

[0074] In Comparative Example 2 shown in FIG. 7, two rectangular parallelepiped heating elements were set as the heating component 3, similar to the structure shown in FIG. 5. A block (5) was stacked on each heating element (3) in a shape combining the lower block (5) and the upper block (5) shown in FIG. 5, and these were brought into contact with the structure as the housing 2. This block (5) was thicker than the block (5) shown in FIG. 5 by a thickness equivalent to the sheet body (6). A tall structure (4) similar to the structure shown in FIG. 5 was placed between the heating elements (3). A sheet body simulating a thermally conductive sheet was placed between each member as the heat transfer material 6.

[0075] In the structures of Example 1, Comparative Example 1, and Comparative Example 2, a heat load of 10 W was applied to the heating element corresponding to the heat-generating component 3. A6063, an Al-Mg-Si aluminum alloy, was set as the material for the structure (2) and the block (5). The sheet body (6) had a thickness of 1 mm and a thermal conductivity of 4.3 W / m K. The initial temperature around the heating element was 25°C.

[0076] Table 1 shows the temperatures of the heating element (3) after a given heat dissipation process as the results of thermal fluid analysis in the structures of Example 1, Comparative Example 1 and Comparative Example 2.

[0077] [Table 1]

[0078] As shown in Table 1, the temperature of the heating element (3) according to Example 1 was 3.8°C lower than that of Comparative Example 1. It can be seen that the structure in which multiple heat transfer blocks 5 are stacked is effective in avoiding interference with tall components and in expanding the cross-sectional area of ​​the heat transfer path.

[0079] Moreover, the temperature of the heating element (3) in Example 1 was 0.5°C higher than that in Comparative Example 2. This result shows that the heat loss due to the heat transfer material 6 such as a thermally conductive sheet does not significantly affect the overall cooling performance.

[0080] From these results, it can be said that a low-cost and efficient cooling structure can be realized by combining simply shaped heat transfer blocks 5, without having to form heat dissipation members into complex shapes by cutting or the like. If the thermal conductivity of the heat transfer material 6 is high, heat loss can be further reduced, so it is preferable to use a heat transfer material 6 with a thermal conductivity of 4.3 W / m K or more. [Explanation of symbols]

[0081] 1 Board 2. Chassis 3 Heat-generating parts (electronic parts) 4. Non-heat-generating components (electronic components) 5 Heat transfer block (heat dissipation material) 6 Heat transfer materials (heat dissipation materials)

Claims

1. A substrate on which a heat generating element is disposed; a heat dissipation section disposed opposite the substrate and configured to dissipate heat generated by the heat generating element to the outside; a plurality of heat transfer blocks for conducting heat generated by the heat generating body toward the heat dissipation portion; a heat transfer elastic body having elasticity for thermally conducting heat generated by the heat generating body toward the heat dissipation portion; Equipped with the heat transfer blocks are each provided as a columnar body that is a rectangular parallelepiped, a cube, a rhombic column, or a cylinder, are stacked on top of each other in a direction perpendicular to the substrate, and are disposed between the heat generating body and the heat dissipation unit; The heat transfer elastic body is disposed between the heat transfer block and the heat dissipation portion.

2. The cooling structure according to claim 1 , The cooling structure, wherein the heat transfer elastic body is disposed at one or more of between the heat transfer blocks and between the heat transfer block and the substrate.

3. The cooling structure according to claim 1 , The heat transfer block is disposed so that a cross-sectional area thereof increases toward the heat dissipation portion.

4. The cooling structure according to claim 1 , A cooling structure in which the heat transfer blocks are stacked so that the contact surface in contact with the heat dissipation portion extends outward by 45 degrees or more from the contact surface in contact with the heat generating element.

5. The cooling structure according to claim 1 , A plurality of heat generating elements that generate heat are disposed on the substrate, A cooling structure in which a portion of the stacked heat transfer blocks is thermally connected to each of the plurality of heat generating elements.

6. The cooling structure according to claim 1 , A tall body having a height greater than that of the heating element is disposed on the substrate, A cooling structure in which a portion of the stacked heat transfer blocks is located above the tall body.

7. The cooling structure according to claim 1 , The heat transfer block is a cooling structure formed of an aluminum alloy.

8. The cooling structure according to claim 7, The heat transfer block is a cooling structure that has been anodized.

9. A substrate on which electronic components are arranged; a heat dissipation section disposed opposite the board and configured to dissipate heat generated by the electronic components to the outside; a plurality of heat transfer blocks for thermally conducting heat generated by the electronic components toward the heat dissipation portion; a heat transfer elastic body having elasticity for thermally conducting heat generated by the electronic component toward the heat dissipation portion, The heat transfer blocks are each provided as a columnar body that is a rectangular prism, a cube, a rhomboidal prism or a cylinder, stacked on top of each other in a direction perpendicular to the substrate, and positioned between the electronic component and the heat dissipation section, and the heat transfer elastic body is positioned between the heat transfer block and the heat dissipation section. An electronic device equipped with a cooling structure.

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