Heat dissipation member

Abstract

To provide a technique that can achieve improved heat dissipation efficiency in a heat dissipation member.SOLUTION: A heat dissipation member according to the present disclosure has a flat-shaped intermediate member formed of ceramics, a first member, and a second member. The intermediate member has a plurality of through holes penetrating a first surface and a second surface located on the opposite sides to each other. The first member has first groove parts in a third surface opposite to the first surface of the intermediate member. The second member has a plurality of second groove parts in a fourth surface opposite to the second surface of the intermediate member, and a heat source is arranged on a fifth surface located on the opposite side of the fourth surface. The first groove part has a first recess depressed from the third surface, and a plurality of first projections located inside the first recess. The second groove part has a second recess depressed from the fourth surface, and a plurality of second projections located inside the second recess. A gap is provided between at least any one of at least one of the plurality of first projections and the first surface and at least one of the plurality of second projections and the second surface.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present disclosure relates to a heat dissipation member.

Background Art

[0002] Conventionally, a heat dissipation member (heat pipe) that efficiently transfers heat from a high-temperature part to a low-temperature part by utilizing the cycle of evaporation and condensation of a working fluid is known.

[0003] Patent Document 1 discloses a metal heat pipe in which a flat intermediate member is interposed between a flat upper member and a flat lower member. Lattice-shaped grooves are formed on the lower surface of the upper member and the upper surface of the lower member, respectively. Further, a plurality of steam holes extending radially and a plurality of fine through holes that generate capillary force are formed in the intermediate member.

[0004] In the heat pipe described in Patent Document 1, a steam diffusion flow path for diffusing the steam of the working fluid in the plane direction is formed by the communication of the steam holes with the respective recesses of the upper member and the lower member. Further, a fine capillary flow path for returning the working fluid in the vertical direction perpendicular to the plane direction is formed by the communication of the through holes with the respective recesses of the upper member and the lower member.

[0005] Further, Patent Document 2 discloses a heat pipe made of ceramics.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present disclosure provides a technique capable of further improving the heat dissipation efficiency in a heat dissipation member.

Means for Solving the Problems

[0008] The heat dissipation member according to one aspect of the present disclosure includes a flat intermediate member made of ceramics, a first member, and a second member. The intermediate member has a plurality of through holes penetrating through a first surface and a second surface located on opposite sides of each other. The first member has a first groove portion on a third surface facing the first surface of the intermediate member. The second member has a plurality of second groove portions on a fourth surface facing the second surface of the intermediate member, and a heat source is disposed on a fifth surface located on the opposite side of the fourth surface. The first groove portion has a first concave portion recessed with respect to the third surface and a plurality of first convex portions located within the first concave portion. The second groove portion has a second concave portion recessed with respect to the fourth surface and a plurality of second convex portions located within the second concave portion. At least one of the plurality of first convex portions and the first surface, and at least one of the plurality of second convex portions and the second surface have a gap therebetween.

Advantages of the Invention

[0009] According to the present disclosure, further improvement in heat dissipation efficiency can be achieved.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

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Figure 16

BEST MODE FOR CARRYING OUT THE INVENTION

[0011] Hereinafter, embodiments for implementing the heat radiating member according to the present disclosure (hereinafter referred to as "embodiments") will be described in detail with reference to the drawings. Note that the present disclosure is not limited by this embodiment. In addition, each embodiment can be appropriately combined within a range that does not conflict with the processing content. In the following embodiments, the same parts are denoted by the same reference numerals, and redundant explanations are omitted.

[0012] In addition, in the embodiments shown below, expressions such as "constant", "orthogonal", "perpendicular", or "parallel" may be used, but these expressions do not necessarily require strict "constant", "orthogonal", "perpendicular", or "parallel". That is, each of the above expressions is assumed to allow deviations such as manufacturing accuracy and installation accuracy.

[0013] In addition, in each of the drawings referred to below, in order to make the description easier to understand, there may be a case where an orthogonal coordinate system is shown that defines the X-axis direction, the Y-axis direction, and the Z-axis direction that are orthogonal to each other, and the positive Z-axis direction is the vertically upward direction.

[0014] First, the overall configuration of the heat dissipation member according to the embodiment will be described with reference to FIG. 1. FIG. 1 is a perspective view of the heat dissipation member according to the embodiment.

[0015] As shown in FIG. 1, the heat dissipation member 1 includes a first member 10, a second member 20, and an intermediate member 30. The first member 10, the second member 20, and the intermediate member 30 are all plate-shaped, and are laminated so that the intermediate member 30 is sandwiched between the first member 10 and the second member 20.

[0016] The heat dissipation member 1 has an internal space, and a working fluid is enclosed in this internal space. As the working fluid, for example, water, hydrocarbon-based compounds, organic liquids such as ethanol or methanol, and liquids such as ammonia can be used.

[0017] The first member 10 has a working fluid injection hole 14 and a gas discharge hole 15. The working fluid is injected into the internal space of the heat dissipation member 1 through the working fluid injection hole 14. Along with the injection of this working fluid, the gas present in the internal space of the first member 10 is discharged to the outside through the gas discharge hole 15. The working fluid injection hole 14 is located near one of the four corners of the first member 10, and the gas discharge hole 15 is located near the corner that is on the diagonal line with the working fluid injection hole 14.

[0018] The working fluid injection hole 14 and the gas discharge hole 15 are closed by sealing members 4 and 5. When the working fluid injection hole 14 and the gas discharge hole 15 are closed, the internal space of the heat dissipation member 1 is sealed and the working fluid is sealed in the internal space. As a result, for example, it is possible to withstand the increase in internal pressure during high-temperature loads and improve heat diffusivity.

[0019] As the sealing members 4 and 5, for example, ceramics of the same material as the first member 10, the second member 20, and the intermediate member 30 can be used. Also, as the sealing members 4 and 5, ceramics of a material different from that of the first member 10, the second member 20, and the intermediate member 30 may be used. Further, as the sealing members 4 and 5, not only ceramics but also metals, resins, etc. may be used. Also, an adhesive may be interposed between the working fluid injection hole 14 and the gas discharge hole 15 and the sealing members 4 and 5. As such an adhesive, for example, resins such as silicone and polyimide can be used.

[0020] The working fluid is filled, for example, at a ratio of 10% by volume or more and 95% by volume or less with respect to the total volume of the internal space of the working region 100. Preferably, the above ratio is 30% by volume or more and 75% by volume or less. More preferably, the above ratio is 40% by volume or more and 65% by volume or less. Also, the remaining part of the internal space of the heat dissipation member 1 other than the working fluid is in a vacuum state including a part of the vaporized working fluid. Thereby, since the vapor-liquid equilibrium can be maintained even in a high-temperature environment, it is difficult to dry out, and since heat is efficiently diffused even in a low-temperature environment, the heat diffusivity can be increased in various temperature ranges.

[0021] The first member 10, the second member 20, and the intermediate member 30 are made of ceramics. As the ceramics constituting the first member 10, the second member 20, and the intermediate member 30, for example, alumina (Al2O3), zirconia (ZrO2), silicon carbide (SiC), silicon nitride (Si3N4), aluminum nitride (AlN), cordierite (Mg2Al3(AlSi5O 18 ))), silicon-impregnated silicon carbide (SiSiC), etc. can be used. Also, the ceramics constituting the first member 10, the second member 20, and the intermediate member 30 may be single crystals.

[0022] The metal heat dissipation member was difficult to obtain rigidity due to material and manufacturing process reasons, and it was difficult to make it thinner. In addition, since the part of the metal heat dissipation member that comes into contact with the working fluid is made of metal, there was room for improvement in terms of corrosion resistance. On the other hand, since all of the first member 10, the second member 20, and the intermediate member 30 of the heat dissipation member 1 according to the embodiment are made of ceramics, it is easier to make it thinner compared to the metal heat dissipation member, and it also has excellent corrosion resistance.

[0023] In the example shown in FIG. 1, the heat dissipation member 1 is installed with the first member 10 facing upward, but the installation mode of the heat dissipation member 1 is not limited to the example of FIG. 1. For example, the heat dissipation member 1 may be installed with the first member 10 facing downward. Also, the heat dissipation member 1 may be installed vertically, not limited to being placed horizontally as shown in FIG. 1.

[0024] Next, the configuration of the first member 10 will be described with reference to FIG. 2. FIG. 2 is a view of the first member 10 according to the embodiment as seen from the negative Z-axis direction to the positive Z-axis direction.

[0025] FIG. 2 shows the lower surface of the first member 10, specifically, the surface (the third surface) that faces the upper surface (the first surface) of the intermediate member 30. As shown in FIG. 2, the first member 10 has a lattice-shaped first groove portion 11 on the third surface.

[0026] The first groove portion 11 has a first concave portion 11a that is recessed with respect to the third surface, and a plurality of first convex portions 11b that are located within the first concave portion 11a. The first concave portion 11a is located at the central portion of the third surface, and the contour in plan view is, for example, a quadrilateral. The plurality of first convex portions 11b are arranged at intervals in the vertical direction (Y-axis direction) and the horizontal direction (X-axis direction) within the first concave portion 11a. Due to these first concave portion 11a and the plurality of first convex portions 11b, the first groove portion 11 has a lattice shape.

[0027] Hereinafter, the region on the third surface of the first member 10 where the first groove portion 11 is located will be referred to as the "groove formation region 100". Note that the above-described working fluid injection hole 14 and gas discharge hole 15 are located in the groove formation region 100.

[0028] Next, the configuration of the second member 20 will be described with reference to FIG. 3. FIG. 3 is a view of the second member 20 according to the embodiment as seen from the +Z-axis side in the -Z-axis direction.

[0029] FIG. 3 shows the upper surface of the second member 20, specifically, the surface (the fourth surface) facing the lower surface (the second surface) of the intermediate member 30. As shown in FIG. 3, the second member 20 has a lattice-shaped second groove portion 21 on the fourth surface.

[0030] The second groove portion 21 has a second concave portion 21a recessed with respect to the fourth surface and a plurality of second convex portions 21b located within the second concave portion 21a. The second concave portion 21a is located at the central portion of the fourth surface, and the contour in plan view is, for example, a quadrilateral. The plurality of second convex portions 21b are arranged at intervals in the vertical direction (Y-axis direction) and the horizontal direction (X-axis direction) within the second concave portion 21a. With these second concave portion 21a and the plurality of second convex portions 21b, the second groove portion 21 has a lattice shape.

[0031] Hereinafter, the region on the fourth surface of the second member 20 where the second groove portion 21 is located will be referred to as the "groove formation region 200".

[0032] The size of the groove formation region 200 in the second member 20 is the same as the size of the groove formation region 100 in the first member 10. Also, the position of the groove formation region 200 on the fourth surface of the second member 20 is the same as the position of the groove formation region 100 on the third surface of the first member 10.

[0033] A heat source is disposed on the lower surface (the fifth surface) located on the side opposite to the upper surface (the fourth surface) of the second member 20.

[0034] Thus, by forming the shapes of the first groove portion 11 and the second groove portion 21 into a lattice shape, the working fluid can be efficiently circulated in the internal space of the heat dissipation member 1. Note that the shapes of the first groove portion 11 and the second groove portion 21 do not necessarily have to be a lattice shape.

[0035] Next, the configuration of the intermediate member 30 will be described with reference to FIG. 4. FIG. 4 is a view of the intermediate member 30 according to the embodiment as seen from the positive Z-axis direction toward the negative Z-axis direction.

[0036] As shown in FIG. 4, the intermediate member 30 has a rectangular frame-shaped edge portion 31, a circular central portion 32 in plan view located inside the edge portion 31, and a plurality of connection portions 33 located between the central portion 32 and the edge portion 31 and connecting the central portion 32 and the edge portion 31. In the example shown in FIG. 4, the central portion 32 is located at the center of the intermediate member 30. Further, the plurality of connection portions 33 extend radially while widening from the central portion 32 toward the edge portion 31 with intervals therebetween.

[0037] The intermediate member 30 further has a plurality of steam holes 35 and a plurality of through holes 37. Both the plurality of steam holes 35 and the plurality of through holes 37 penetrate the upper surface (first surface) and the lower surface (second surface) of the intermediate member 30.

[0038] The plurality of steam holes 35 function as part of the flow path for the vapor of the working fluid. The plurality of steam holes 35 are located between two adjacent connection portions 33. That is, the plurality of steam holes 35 and the plurality of connection portions 33 are alternately positioned in the circumferential direction. The plurality of steam holes 35 extend radially while widening from the central portion 32 toward the edge portion 31 with intervals therebetween, similar to the plurality of connection portions 33.

[0039] The plurality of through holes 37 function as part of the flow path for the working fluid. The through holes 37 are fine holes having a smaller opening area compared to the above-described steam holes 35. Specifically, the through holes 37 are small enough to cause capillary action in the working fluid passing through the through holes 37.

[0040] The plurality of through holes 37 are located in the central portion 32 and the plurality of connection portions 33 of the intermediate member 30. Here, the specific configuration of the plurality of through holes 37 will be described with reference to FIG. 5. FIG. 5 is an enlarged view of the periphery of the central portion 32 in the intermediate member 30.

[0041] As shown in FIG. 5, the plurality of through-holes 37 include a plurality of types (here, three types) of through-holes having different opening diameters when the intermediate member 30 is viewed from the positive Z-axis direction to the negative Z-axis direction (in other words, the opening diameter on the side of the first member 10), specifically, a plurality of first through-holes 37a, one second through-hole 37b, and a plurality of third through-holes 37c.

[0042] The plurality of first through-holes 37a are located at each connection portion 33 of the intermediate member 30. For example, the opening diameter of the first through-hole 37a as viewed from the side of the first member 10 is, for example, 250 μm or more and 700 μm or less.

[0043] The second through-hole 37b is located at the center of the central portion 32 of the intermediate member 30. The second through-hole 37b has a larger diameter than the first through-hole 37a. For example, the opening diameter of the second through-hole 37b as viewed from the side of the first member 10 is, for example, 550 μm or more and 900 μm or less. Note that a plurality of second through-holes 37b may be provided in the central portion 32.

[0044] The plurality of third through-holes 37c are located at each connection portion 33 of the intermediate member 30. Specifically, the plurality of third through-holes 37c are located in a region near the central portion 32 among the connection portions 33. Further, the plurality of third through-holes 37c are also located in the central portion 32 of the intermediate member 30. Specifically, the plurality of third through-holes 37c are located on the outer peripheral side of the central portion 32, that is, in a region near the connection portion 33. The third through-hole 37c has a smaller diameter than the first through-hole 37a. For example, the opening diameter of the third through-hole 37c as viewed from the side of the first member 10 is, for example, 200 to 400 μm.

[0045] In this way, the plurality of through-holes 37 are positioned in the order of the second through-hole 37b having a large opening diameter, the third through-hole 37c having a small opening diameter, and the first through-hole 37a having a medium opening diameter, from the center to the outer periphery of the intermediate member 30.

[0046] Since the distance from the central portion 32 of the intermediate member 30 to the steam holes 35 is longer than that of the connection portion 33, the circulation of the working fluid tends to stagnate in the central portion 32. That is, the central portion of the heat radiating member 1 is likely to become a heat spot. On the other hand, in the heat radiating member 1 according to the embodiment, by providing the second through hole 37b having a large opening diameter in the central portion 32 of the intermediate member 30, the steam generated in the central portion 32 can be moved from the second through hole 37b to the low temperature side. Thereby, the circulation of the working fluid in the central portion of the heat radiating member 1 can be promoted. Therefore, it is possible to suppress the central portion of the heat radiating member 1 from becoming a heat spot.

[0047] The density of the through holes 37 in the central portion 32 of the intermediate member 30 is smaller than the density of the through holes 37 in the connection portion 33 of the intermediate member 30. In other words, when the intermediate member 30 is viewed from the positive Z-axis side to the negative Z-axis direction, the ratio of the opening area of the through holes 37 (the second through hole 37b and the plurality of third through holes 37c) occupying the area of the central portion 32 is smaller than the ratio of the opening area of the through holes 37 (the plurality of first through holes 37a and the plurality of third through holes 37c) occupying the area of the connection portion 33. Thus, by relatively reducing the density of the through holes 37 in the central portion 32, a decrease in the strength of the intermediate member 30 can be suppressed.

[0048] FIG. 6 is a view in which the groove forming region 100 shown in FIG. 2 and the groove forming region 200 shown in FIG. 3 are superimposed on the intermediate member 30 shown in FIG. 4.

[0049] As shown in FIG. 6, the groove forming regions 100 and 200 formed in the first member 10 and the second member 20 overlap with the edge portion 31 of the intermediate member 30. That is, the groove forming regions 100 and 200 extend outward beyond the region (hereinafter referred to as the "hole forming region") where the plurality of steam holes 35 and the plurality of through holes 37 are formed in the intermediate member 30.

[0050] In this way, by making the groove formation regions 100 and 200 of the first member 10 and the second member 20 wider than the hole formation region of the intermediate member 30, the internal space of the heat dissipation member 1 can be expanded outward as compared with the case where the groove formation regions 100 and 200 are made to be of the same degree as the hole formation region.

[0051] The heat source is disposed at the center of the heat dissipation member 1, and the temperature of the heat dissipation member 1 becomes lower as it is farther from the heat source, that is, as it is closer to the outer peripheral portion of the heat dissipation member 1. Further, the vapor of the working fluid condenses into a liquid by moving to the low temperature region. Therefore, by expanding the internal space of the heat dissipation member 1 outward, condensation of the working fluid is more likely to occur. For this reason, dry-out can be made difficult to occur.

[0052] Here, an example in which the first groove formation region 110 and the second groove formation region 120 extend outward beyond the hole formation region of the intermediate member 30 has been shown, but the present invention is not limited to this, and the hole formation region of the intermediate member 30 may extend outward beyond the first groove formation region 110 and the second groove formation region 120.

[0053] Next, the flow of the working fluid in the heat dissipation member 1 according to the embodiment will be described with reference to FIGS. 7 and 8. FIGS. 7 and 8 are diagrams for explaining the flow of the working fluid in the heat dissipation member 1 according to the embodiment. Note that FIG. 7 is a diagram in which the edge portion 31 is omitted from the diagram shown in FIG. 6, and FIG. 8 is a cross-sectional view taken along line IX-IX in FIG. 7. Further, in FIGS. 7 and 8, the flow of the vapor is indicated by a white arrow, and the flow of the liquid is indicated by a black arrow.

[0054] The working fluid is vaporized by being heated by the heat source and becomes vapor. As described above, the heat source is disposed at the center of the lower surface (the fifth surface) of the second member 20 (see FIGS. 1 and 3). For this reason, the vapor of the working fluid is generated at the center of the high temperature side space (the space sandwiched between the second member 20 and the intermediate member 30) where the heat source is disposed.

[0055] The vapor of the working fluid diffuses in the in-plane direction (XY plane direction) of the heat dissipation member 1 through the groove formation region 200 (the second groove portion 21) (refer to the white arrow shown in FIG. 7), and moves upward to the low-temperature side space (the space sandwiched between the first member 10 and the intermediate member 30) through the plurality of vapor holes 35 (refer to the black arrow shown in FIG. 8).

[0056] The vapor that has moved to the low-temperature side space condenses due to the temperature drop and becomes a liquid. The liquefied working fluid moves toward the central portion of the heat dissipation member 1 through the capillary force of the groove formation region 100 (the first groove portion 11) (refer to the black arrow shown in FIG. 7). In this process, the working fluid enters the through hole 37 and is returned to the high-temperature side space by the capillary force of the through hole 37 (refer to the black arrow shown in FIG. 8). By repeating the above cycle, the heat dissipation member 1 can transfer heat from the heat source.

[0057] Next, the specific configuration of the through hole 37 formed in the intermediate member 30 will be described with reference to FIG. 9. FIG. 9 is an enlarged view of the H portion shown in FIG. 8.

[0058] As shown in FIG. 9, the through hole 37 has a reduced diameter from the upper surface 301 (the first surface), which is the low-temperature side surface of the plate surface of the intermediate member 30, toward the lower surface 302 (the second surface), which is the high-temperature side surface. In other words, the opening diameter of the through hole 37 becomes narrower from the low-temperature side toward the high-temperature side.

[0059] By making the opening diameter of the low-temperature side of the through hole 37 relatively large, it becomes easier for the working fluid to enter the through hole 37. Also, by making the opening diameter of the high-temperature side of the through hole 37 relatively small, the magnitude of the capillary force in the through hole 37 can be increased as it goes toward the high-temperature side. Thereby, the working fluid that has entered the through hole 37 from the low-temperature side can be accelerated and pulled toward the high-temperature side by the gradually increasing capillary force.

[0060] Thus, according to the heat dissipation member 1, by forming the through holes 37 in a tapered shape, the circulation efficiency of the working fluid can be increased. Further, according to the heat dissipation member 1, by forming the through holes 37 in a tapered shape, the reverse flow of the working fluid or steam can also be suppressed.

[0061] Note that, as described above, among the plurality of through holes 37, the second through hole 37b (see FIG. 5) is also used as a flow path for steam. Therefore, the second through hole 37b may be formed in a straight shape with a constant opening diameter so that steam can move easily.

[0062] The surface roughness of the inner surface 371 of the through hole 37 is larger than the surface roughness of the upper surface 301 (first surface) of the intermediate member 30. The greater the surface roughness, the higher the wettability. Therefore, the working fluid is more likely to enter the inside of the through hole 37 having a larger surface roughness.

[0063] Thus, by making the surface roughness of the inner surface 371 of the through hole 37 larger than the surface roughness of the upper surface 301 (first surface) of the intermediate member 30, the circulation efficiency of the working fluid can be increased.

[0064] Also, the surface roughness of the inner surface 211 of the second groove portion 21 is larger than the surface roughness of the inner surface 371 of the through hole 37. As a result, the working fluid is more likely to be discharged from the inside of the through hole 37 to the second groove portion 21.

[0065] Thus, by making the surface roughness of the inner surface 211 of the second groove portion 21 larger than the surface roughness of the inner surface 371 of the through hole 37, the circulation efficiency of the working fluid can be increased.

[0066] Next, an example of the manufacturing method of the heat dissipation member 1 described above will be explained. First, using the raw materials of the first member 10, the second member 20, and the intermediate member 30, a green sheet is formed by the doctor blade method or the roll compaction method, etc., and a laminate is obtained by laminating a plurality of green sheets.

[0067] Subsequently, the obtained laminate is subjected to laser processing or punching using a die to obtain the molded bodies of the first member 10, the second member 20, and the intermediate member 30. For example, by subjecting the laminate to laser processing, a molded body of the intermediate member 30 in which a plurality of steam holes 35 and a plurality of through holes 37 are formed can be obtained. By the laser processing at this time, the surface roughness of the inner surface 371 of the through hole 37 can be made larger than the surface roughness of the upper surface 301 (first surface) of the intermediate member 30.

[0068] Further, by subjecting the obtained laminate to laser processing, molded bodies of the first member 10 and the second member 20 in which groove formation regions 100 and 200 are formed are obtained. By adjusting the output of the laser in the laser processing at this time, the surface roughness of the inner surface 211 of the second groove portion 21 can be made larger than the surface roughness of the inner surface 371 of the through hole 37.

[0069] Subsequently, the molded bodies of the first member 10, the second member 20, and the intermediate member 30 are stacked and fired in the order of the second member 20, the intermediate member 30, and the first member 10 to obtain a fired body in which the first member 10, the second member 20, and the intermediate member 30 are integrated. In this way, the first member 10, the second member 20, and the intermediate member 30 are integrally formed. Therefore, since an adhesive or the like is not required, a highly reliable heat dissipation member 1 can be obtained.

[0070] Subsequently, the working fluid is injected into the inside of the fired body from the working fluid injection hole 14 provided in the first member 10. The gas present inside the fired body is discharged to the outside from the gas discharge hole 15 of the first member 10 as the working fluid is injected.

[0071] Subsequently, the working fluid injection hole 14 and the gas discharge hole 15 are closed using the sealing members 4 and 5 and an adhesive. Thereby, the heat dissipation member 1 is obtained.

[0072] (First Modified Example) FIG. 10 is a diagram showing the configuration of the through hole according to the first modified example. As shown in FIG. 10, the heat dissipation member 1A according to the first modified example has an intermediate member 30A.

[0073] The intermediate member 30A according to the first modification has a chamfered portion 372 between the upper surface 301 (first surface) and the through hole 37. The chamfered portion 372 has, for example, a curved convex surface connecting the upper surface 301 (first surface) and the inner surface 371 of the through hole 37.

[0074] By providing the chamfered portion 372 between the upper surface 301 (first surface) and the through hole 37 in this way, the working fluid can be made to easily enter the through hole 37.

[0075] Note that the chamfered portion 372 does not necessarily have to be curved (R-surface shape), and may be, for example, planar (C-surface shape).

[0076] When manufacturing a molded body of the intermediate member 30A having the chamfered portion 372, for example, when performing laser processing or punching with a mold on a laminate of green sheets, the output of the laser processing or the shape of the mold may be adjusted. Thereafter, by firing the obtained molded body together with the first member 10 and the second member 20, a fired body in which the first member 10, the second member 20, and the intermediate member 30A are integrated can be obtained.

[0077] (Second Modification) FIG. 11 is a diagram showing the configuration of the through hole according to the second modification. As shown in FIG. 11, the heat dissipation member 1B according to the second modification has an intermediate member 30B.

[0078] The intermediate member 30B according to the second modification meanders with respect to the XY plane. And the heat dissipation member 1B has a first gap 310 between at least one of the plurality of first convex portions 11b of the first groove portion 11 and the upper surface 301 of the intermediate member 30B.

[0079] According to such a heat dissipation member 1B, not only the first groove portion 11 but also the first gap 310 can allow the working fluid to flow through. The working fluid is guided to the through hole 37 by the capillary force in the first gap 310 and enters the through hole 37. Thus, according to the heat dissipation member 1B, by having the first gap 310, the circulation efficiency of the working fluid can be further enhanced.

[0080] Further, the heat dissipation member 1B has a second gap 320 between at least one of the plurality of second convex portions 21b of the second groove portion 21 and the lower surface 302 of the intermediate member 30B.

[0081] According to such a heat dissipation member 1B, not only the second groove portion 21 but also the second gap 320 can allow the vapor of the working fluid to flow through. Thus, according to the heat dissipation member 1B, by having the second gap 320, the diffusion of the vapor of the working fluid can be promoted. That is, the circulation efficiency of the working fluid can be increased.

[0082] When manufacturing a molded body of the intermediate member 30B that meanders with respect to the XY plane, for example, the pressure applied to the laminate when laminating the green sheets may be adjusted. For example, by applying pressure unevenly to the laminate, a molded body of the intermediate member 30B that meanders with respect to the XY plane can be obtained. Thereafter, by firing the obtained molded body together with the first member 10 and the second member 20, a fired body in which the first member 10, the second member 20, and the intermediate member 30B are integrated can be obtained.

[0083] Also, the surface roughness of the inner surface 211 of the second groove portion 21 is larger than the surface roughness of the lower surface 302 (second surface) of the intermediate member 30. Thereby, the working fluid is more likely to be discharged from the lower surface 302 (second surface) of the intermediate member 30 to the second groove portion 21.

[0084] Thus, by making the surface roughness of the inner surface 211 of the second groove portion 21 larger than the surface roughness of the lower surface 302 (second surface) of the intermediate member 30, the circulation efficiency of the working fluid can be increased.

[0085] Note that the surface roughness of the upper surface 301 (first surface) of the intermediate member 30, the inner surface 371 of the through hole 37, the lower surface 302 (second surface) of the intermediate member 30, and the inner surface 211 of the second groove portion 21 may be adjusted, for example, within a range where the arithmetic mean roughness Ra is 0.08 μm or more and 0.4 μm or less, 0.3 μm or more and 0.6 μm or less, 0.08 μm or more and 0.4 μm or less, and 0.5 μm or more and 0.8 μm or less, respectively.

[0086] (Third Modification Example) FIG. 12 is a side view of the heat radiating member according to the third modification example. As shown in FIG. 12, the heat radiating member 1C may have a conductor 6 on the lower surface (the fifth surface) of the second member 20 which is the high-temperature side.

[0087] Since a heat radiating member made of metal becomes a conductor itself, it is necessary to provide an insulator in order to form a circuit or the like. On the other hand, according to the heat radiating member 1C made of ceramics which is an insulator, by using the conductor 6 as a wiring or an electrode, it is possible to directly mount electronic components.

[0088] (Fourth Modification Example) FIG. 13 is a side view of the heat radiating member according to the fourth modification example. As shown in FIG. 13, the heat radiating member 1D may have a coating layer 7 that covers at least a part of the conductor 6 on the lower surface (the fifth surface) of the second member 20 which is the high-temperature side.

[0089] (Fifth Modification Example) FIG. 14 is a side view of the heat radiating member according to the fifth modification example. As shown in FIG. 14, the heat radiating member 1E may have a heat sink 8 on the upper surface (the sixth surface) of the first member 10 which is the low-temperature side. The material of the heat sink 8 may be metal or ceramics. The heat sink 8 has, for example, a plurality of fins 81. Thereby, the heat radiation effect can be further enhanced.

[0090] (Sixth Modification Example) FIG. 15 is a side view of the heat radiating member according to the sixth modification example. As shown in FIG. 15, the heat radiating member 1F may have a first member 10F in which a plurality of fins 18 made of ceramics are integrally formed on the upper surface (the sixth surface). The first member 10F can be obtained, for example, by firing a molded body in which a plurality of fins 18 are formed by punching or laser processing a laminate of green sheets with a mold. According to such a heat radiating member 1F, since an adhesive or the like for attaching the fins 18 is not required, the reliability can be improved. Also, heat radiation is not hindered by an adhesive or the like.

[0091] Among the plurality of fins 18, it is preferable that some are located outside the internal space of the heat dissipation member 1F formed by the groove formation region 100 of the first member 10F, the groove formation region 200 of the second member 20, the steam holes 35 and the through holes 37 of the intermediate member 30. Thereby, the heat dissipation effect can be further enhanced.

[0092] (Seventh Modified Example) FIG. 16 is a side view of the heat dissipation member according to the seventh modified example. As shown in FIG. 16, the heat dissipation member 1G may have a temperature control plate 9 on the upper surface (the sixth surface) of the first member 10 which is the low temperature side. The temperature control plate 9 can use, for example, a water-cooled type, an air-cooled type, or a resistance heating type.

[0093] As described above, the heat dissipation member according to the embodiment (for example, heat dissipation members 1, 1A to 1G) includes a flat intermediate member made of ceramics (for example, intermediate members 30, 30A, 30B), a first member (for example, first members 10, 10F), and a second member (for example, second member 20). The intermediate member has a plurality of through holes (for example, through hole 37) that penetrate a first surface (for example, upper surface 301) and a second surface (for example, lower surface 302) located on opposite sides of each other. The first member has a first groove portion (for example, first groove portion 11) on a third surface (for example, lower surface) facing the first surface of the intermediate member. The second member has a plurality of second groove portions (for example, second groove portions 21) on a fourth surface (for example, upper surface) facing the second surface of the intermediate member, and a heat source is disposed on a fifth surface (for example, lower surface) located on the opposite side of the fourth surface. Further, the first groove portion has a first concave portion (for example, first concave portion 11a) recessed with respect to the third surface, and a plurality of first convex portions (first convex portions 11b) located within the first concave portion. The second groove portion has a second concave portion (for example, second concave portion 21a) recessed with respect to the fourth surface, and a plurality of second convex portions (for example, second convex portions 21b) located within the second concave portion. Moreover, the heat dissipation member according to the embodiment has a gap (for example, first gap 310, second gap 320) at least between at least one of the plurality of first convex portions and the first surface and at least one of the plurality of second convex portions and the second surface. Thereby, since the working fluid flows not only through the first groove portion and the second groove portion but also through the above-described gap, the circulation efficiency of the working fluid can be increased.

[0094] The surface roughness of the inner surface of the through hole of the intermediate member is greater than the surface roughness of the first surface. Thereby, since the working fluid easily enters the inside of the through hole, the circulation efficiency of the working fluid can be increased. Therefore, further improvement in heat dissipation efficiency can be achieved.

[0095] The first groove portion and the second groove portion are in a lattice shape. Thereby, the working fluid can be efficiently circulated in the internal space of the heat dissipation member.

[0096] The surface roughness of the inner surface of the second groove portion is larger than the surface roughness of the inner surface of the through hole. As a result, the working fluid is easily discharged from the inside of the through hole to the second groove portion, so that the circulation efficiency of the working fluid can be increased.

[0097] The intermediate member has an edge portion (for example, edge portion 31), a central portion (for example, central portion 32), and a plurality of connection portions (for example, connection portion 33) located between the central portion and the edge portion and connecting the central portion and the edge portion. Further, the plurality of through holes include a plurality of first through holes (for example, first through hole 37a) located in the connection portion and at least one second through hole (for example, second through hole 37b) located in the central portion and having a larger opening area than the first through hole. By providing a second through hole with a large opening diameter in the central portion of the intermediate member, it is possible to suppress the central portion of the heat dissipation member from becoming a heat spot.

[0098] In a plan view, the first groove portion and the second groove portion overlap with the edge portion. By expanding the internal space of the heat dissipation member outward, condensation of the working fluid is likely to occur, so that it is possible to make it difficult to cause dry-out.

[0099] The through hole has a reduced diameter from the first surface side toward the second surface side. By relatively increasing the opening diameter on the low-temperature side, it is possible to make it easier for the working fluid to enter the through hole. Further, by relatively reducing the opening diameter on the high-temperature side, it is possible to increase the magnitude of the capillary force in the through hole as going toward the high-temperature side. Therefore, the circulation efficiency of the working fluid can be increased. That is, further improvement in heat dissipation efficiency can be achieved.

[0100] The intermediate member has a chamfered portion (for example, chamfered portion 372) between the first surface and the through hole. Thereby, it is possible to make it easier for the working fluid to enter the through hole.

[0101] The density of the through holes in the central portion of the intermediate member is smaller than the density of the through holes in the connection portion of the intermediate member. Thus, by relatively reducing the density of the through holes in the central portion, it is possible to suppress a decrease in the strength of the intermediate member.

[0102] In the above-described embodiments and modifications, an example in which the shape of the through hole is a shape (tapered shape) that decreases in diameter from the first surface side to the second surface side of the intermediate member has been described. However, the shape of the through hole is not limited to the tapered shape. For example, the shape of the through hole may be a shape (reverse tapered shape) that increases in diameter from the first surface side to the second surface side of the intermediate member. Further, the shape of the through hole may be a shape (straight shape) in which the diameter is substantially constant from the first surface side to the second surface side of the intermediate member.

[0103] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. Indeed, the above-described embodiments can be embodied in various forms. Further, the above embodiments may be omitted, replaced, or changed in various forms without departing from the scope and spirit of the appended claims.

Explanation of Reference Numerals

[0104] 1: Heat dissipation member 4, 5: Sealing member 6: Conductor 7: Coating layer 8: Heat sink 9: Temperature control plate 10: First member 11: First groove portion 11a: First concave portion 11b: First convex portion 14: Working fluid injection hole 15: Gas discharge hole 20: Second member 21: Second groove portion 21a: Second concave portion 21b: Second convex portion 30: Intermediate member 31: Edge portion 32: Central portion 33: Connection portion 35: Vapor hole 37: Through hole 37a: First through hole 37b: Second through hole 37c: Third through hole 100: Groove formation region 200: Groove formation region

Claims

1. a flat intermediate member made of ceramics, the intermediate member having a plurality of through holes penetrating a first surface and a second surface located opposite to each other; a first member having a flat plate shape and made of ceramics, the first member having a first groove portion on a third surface opposite to the first surface of the intermediate member; a flat-plate-like second member made of ceramics, the second member having a fourth surface facing the second surface of the intermediate member, the second member having a plurality of second grooves on a fourth surface thereof, the fifth surface being located on the opposite side to the fourth surface, and a heat source being disposed on the fifth surface of the second member; having the first groove portion has a first recess portion recessed relative to the third surface and a plurality of first protrusion portions positioned within the first recess portion, the second groove portion has a second recess portion recessed relative to the fourth surface and a plurality of second protrusion portions located within the second recess portion, the first protrusion has a first top surface facing the first surface, and at least one of the plurality of first protrusions has the first top surface in contact with the first surface; the second protrusion has a second top surface facing the second surface, and at least one of the plurality of second protrusions has the second top surface in contact with the second surface; A heat dissipation member having a gap between the first top surface and the first surface, or between the second top surface and the second surface, of at least one of the plurality of first convex portions.

2. The heat dissipation member according to claim 1 , wherein the intermediate member has an inner surface of the through hole with a surface roughness greater than a surface roughness of the first surface.

3. The heat dissipation member according to claim 1 , wherein the through hole has a diameter that decreases from the first surface side toward the second surface side.

4. 4. The heat dissipation member according to claim 1, wherein the first groove portion and the second groove portion are in a lattice pattern.

5. 5. The heat dissipation member according to claim 1, wherein the intermediate member has a chamfered portion between the first surface and the through hole.

6. the intermediate member has an edge portion, a central portion, and a plurality of connection portions located between the central portion and the edge portion and connecting the central portion and the edge portion; A heat dissipation member described in any one of claims 1 to 5, wherein the plurality of through holes include a plurality of first through holes located in the connection portion and at least one second through hole located in the central portion and having a larger opening area than the first through holes.

7. The heat dissipation member according to claim 6 , wherein a density of the through holes in the central portion is lower than a density of the through holes in the connection portion.

8. the intermediate member has an edge portion, a central portion, and a plurality of connection portions located between the central portion and the edge portion and connecting the central portion and the edge portion; 8. The heat dissipation member according to claim 1, wherein the first groove portion and the second groove portion overlap the edge portion in a plan view.

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