Thermal device

Abstract

This thermal device comprises: a flat intermediate member comprising a ceramic; a first member; and a second member. The intermediate member has a plurality of through holes that pass through a first surface and a second surface which are positioned on opposite sides from each other. The first member has a first groove on a third surface which faces the first surface of the intermediate member. The second member has a second groove on a fourth surface which faces the second surface of the intermediate member. A heat source is disposed on a fifth surface of the second member which is positioned on the opposite side from fourth surface. The first groove has a first recess that is recessed with respect to the third surface and a plurality of first protrusions which are positioned in the first recess. The second groove has a second recess which is recessed with respect to the fourth surface and a plurality of second protrusions which are positioned in the second recess. The second groove has, on the bottom surface of the second groove, a plurality of third grooves which are narrower in width than the second groove.

Description

Thermal Devices

[0001] The present disclosure relates to thermal devices.

[0002] Conventionally, heat dissipation components that utilize the latent heat of a fluid are known. For example, a vapor chamber, which is one type of heat dissipation component, dissipates heat from a heat-generating component by transporting heat from a high-temperature portion to a low-temperature portion by utilizing the latent heat generated by the evaporation and condensation of a working fluid sealed inside (see Patent Document 1).

[0003] International Publication No. 2021 / 172479

[0004] A thermal device according to one aspect of the present disclosure includes a flat-plate-shaped intermediate member made of ceramic, 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 opposite each other. The first member has a first groove portion in a third surface opposite the first surface of the intermediate member. The second member has a second groove portion in a fourth surface opposite the second surface of the intermediate member, and a heat source is disposed on a fifth surface located opposite the fourth surface. The first groove portion has a first recessed portion recessed relative to the third surface and a plurality of first protrusions located within the first recessed portion. The second groove portion has a second recessed portion recessed relative to the fourth surface and a plurality of second protrusions located within the second recessed portion. The second groove portion has a plurality of third grooves narrower than the second grooves at the bottom surface of the second groove portion.

[0005] FIG. 1 is a perspective view of a thermal device according to an embodiment. FIG. 2 is a view of a first member according to an embodiment, viewed from the negative Z-axis side in the positive Z-axis direction. FIG. 3 is a view of a second member according to an embodiment, viewed from the positive Z-axis side in the negative Z-axis direction. FIG. 4 is a view of an intermediate member according to an embodiment, viewed from the positive Z-axis side in the negative Z-axis direction. FIG. 5 is a view in which the first groove formation region shown in FIG. 2 and the second groove formation region shown in FIG. 3 are superimposed on the intermediate member shown in FIG. 4. FIG. 6 is a view in which the third frame region is omitted from the view shown in FIG. 5. FIG. 7 is a view for explaining the flow of working fluid in a heat dissipation member according to an embodiment. FIG. 8 is a schematic cross-sectional view showing the configuration of a second groove portion and a first groove portion according to an embodiment. FIG. 9 is a schematic plan view showing the configuration of a second groove portion according to an embodiment. FIG. 10 is a schematic plan view showing the configuration of a second groove portion according to Alternative Embodiment 1. FIG. 11 is a schematic plan view showing the configuration of a second groove portion according to Alternative Embodiment 2. FIG. 12 is a schematic plan view showing the configuration of a second groove portion according to Alternative Embodiment 3.

[0006] Hereinafter, a detailed description will be given of a thermal device according to the present disclosure (hereinafter referred to as an "embodiment") with reference to the drawings. Note that the present disclosure is not limited to the embodiment. Furthermore, the embodiments can be appropriately combined as long as the processing contents are not contradictory. Furthermore, the same components in the following embodiments are given the same reference numerals, and redundant explanations will be omitted.

[0007] Furthermore, in the following embodiments, expressions such as "constant," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not necessarily mean "constant," "orthogonal," "perpendicular," or "parallel" in the strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision, installation precision, etc.

[0008] In addition, in the drawings referred to below, for ease of understanding, an orthogonal coordinate system may be shown in which the X-axis direction, Y-axis direction, and Z-axis direction, which are perpendicular to each other, are defined, and the positive Z-axis direction is the vertically upward direction.

[0009] The thermal device of the present disclosure can be used as a heat dissipation member that dissipates heat from a heat source. The thermal device of the present disclosure can also be used as a heat equalization member that transfers heat from a heat source to the outside in a substantially uniform manner. Hereinafter, the thermal device may also be referred to as a heat dissipation member. Hereinafter, a heat dissipation member that efficiently transfers heat from a high-temperature portion to a low-temperature portion by utilizing latent heat associated with the evaporation and condensation of a fluid will be described as an example of a heat dissipation member that is a thermal device according to the present disclosure, specifically, a vapor chamber.

[0010] 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.

[0011] As shown in Fig. 1 , the heat dissipation member 1 has a container 2. The container 2 is made of ceramic. The container 2 may have a first member 10, a second member 20, and an intermediate member 30. In the example of Fig. 1 , the first member 10, the second member 20, and the intermediate member 30 are all plate-shaped, and the first member 10 and the second member 20 sandwich the intermediate member 30.

[0012] The container 2 may have an actuation region 100 and a frame region 200. The actuation region 100 may have an internal space, and the internal space may be filled with a fluid, specifically, a working fluid as a phase-change material. Examples of the working fluid that may be used include water, a hydrocarbon compound, an organic liquid such as ethanol or methanol, and ammonia.

[0013] The frame region 200 is a region that surrounds the operating region 100. In other words, the frame region 200 is a region of the heat dissipation member 1 that is outside the operating region 100. While the operating region 100 is generally hollow, the frame region 200 may be generally solid.

[0014] The frame region 200 is an area that is intentionally made wide in order to reduce, for example, the leakage of working fluid or working fluid vapor from the interface between the first member 10 and the intermediate member 30 or the interface between the second member 20 and the intermediate member 30, or the intrusion of the external atmosphere into the internal space of the operating region 100 from the above-mentioned interfaces, i.e., to ensure the airtightness of the operating region 100.

[0015] The container 2 may have two communication passages 60 that connect the internal space of the operating region 100 with the outside. Although an example in which the container 2 has two communication passages 60 is shown here, the container 2 may have at least one communication passage 60.

[0016] In the embodiment, one of the two communication passages 60 may be used as a flow passage for injecting working fluid, and the other may be used as a flow passage for discharging gas. In this case, in the manufacturing process of the heat dissipation member 1, working fluid is injected into the internal space of the operating region 100 through one of the communication passages 60, and as a result, gas present in the internal space of the operating region 100 is discharged to the outside through the other communication passage 60. As an example, one communication passage 60 is located near one of the four corners of the first member 10, and the other communication passage 60 is located near the corner diagonally opposite to the one communication passage 60.

[0017] Each communication passage 60 is closed by a sealing member 5. This seals the internal space of the heat dissipation member 1, and the working fluid is sealed in the working region 100. In this way, the heat dissipation member 1 is a sealed container with a sealed interior.

[0018] The sealing member 5 may be made of, for example, ceramic, which is the same material as the first member 10, the second member 20, and the intermediate member 30. Alternatively, the sealing member 5 may be made of ceramic, which is different from the materials used for the first member 10, the second member 20, and the intermediate member 30. The sealing member 5 is not limited to ceramic, and may be made of metal, resin, or the like. An adhesive may be interposed between each communication passage 60 and the sealing member 5. Examples of such adhesives that may be used include inorganic adhesives such as metal brazing material and glass sealing material, and organic adhesives such as silicone and polyimide resins.

[0019] The working fluid may be filled at a ratio of 10% by volume to 95% by volume of the total volume of the internal space of the operating region 100, for example. Preferably, the ratio may be 30% by volume to 75% by volume. More preferably, the ratio may be 40% by volume to 65% by volume. Furthermore, the remaining part of the internal space of the operating region 100 other than the working fluid may be in a vacuum state containing a portion of vaporized working fluid. This makes it possible to maintain gas-liquid equilibrium even in high-temperature environments, making it less likely to dry out, and also allows for efficient thermal diffusion even in low-temperature environments, thereby increasing thermal diffusivity over a variety of temperature ranges.

[0020] The first member 10, the second member 20, and the intermediate member 30 are made of ceramic. Examples of ceramics that can be used to form the first member 10, the second member 20, and the intermediate member 30 include alumina (Al ２ O ３ ), zirconia (ZrO ２ ), silicon carbide (SiC), silicon nitride (Si ３ N ４ ), aluminum nitride (AlN), cordierite (Mg ２ Al ３ (AlSi ５ O １８ )), silicon-impregnated silicon carbide (SiSiC), etc. The ceramics constituting the first member 10, the second member 20, and the intermediate member 30 may be polycrystalline or single crystalline.

[0021] It is preferable to use alumina as the ceramic for forming the first member 10, the second member 20, and the intermediate member 30, because it is inexpensive and has excellent processability. Furthermore, alumina is also preferable among ceramics because it has excellent wettability with solvents such as water.

[0022] Metallic heat dissipation members have difficulty in obtaining rigidity due to the material and manufacturing method, making them difficult to make thin and large. Furthermore, because the portions of metallic heat dissipation members that come into contact with the working fluid are made of metal, there is room for improvement in terms of corrosion resistance. In contrast, the heat dissipation member 1 according to the embodiment has the first member 10, the second member 20, and the intermediate member 30 all made of ceramic, making it easier to make it thin compared to metallic heat dissipation members and providing superior 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 orientation of the heat dissipation member 1 is not limited to the example shown in Fig. 1. For example, the heat dissipation member 1 may be installed with the first member 10 facing downward. Furthermore, the heat dissipation member 1 is not limited to being installed horizontally as shown in Fig. 1, but may also be installed vertically.

[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, viewed from the negative Z-axis direction side toward the positive Z-axis direction.

[0025] 2 shows the lower surface of the first member 10, i.e., the third surface that faces the first surface, which is the upper 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 may have a first recess 11a recessed relative to the third surface and a plurality of first protrusions 11b located within the first recess 11a. The first recess 11a is located in the center of the third surface. The outline of the first recess 11a in plan view may be, for example, circular. However, this is not limiting, and the outline of the first recess 11a in plan view may be, for example, rectangular.

[0027] The first protrusions 11b are arranged in the first recess 11a at intervals in the vertical direction (here, the X-axis direction) and the horizontal direction (here, the Y-axis direction). The first recess 11a and the first protrusions 11b may form the first groove 11 in a lattice shape.

[0028] Hereinafter, the area of ​​the third surface of the first member 10 where the first groove portion 11 is located will be referred to as the "first groove formation area 110." The first groove formation area 110 constitutes part of the operating area 100. The first member 10 also has a rectangular frame-shaped first frame area 210 that surrounds the first groove formation area 110. The first frame area 210 constitutes part of the frame area 200.

[0029] Two through holes 61 that penetrate the first member 10 in the thickness direction, here in the Z-axis direction, may be located in the first frame region 210. The through holes 61 form part of the communication passage 60.

[0030] 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, viewed from the positive Z-axis direction side toward the negative Z-axis direction.

[0031] 3 shows the fourth surface of the second member 20, which faces the second surface that is the upper 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.

[0032] The second groove portion 21 may have a second recess 21a recessed relative to the fourth surface and a plurality of second protrusions 21b located within the second recess 21a. The second recess 21a is located in the center of the fourth surface. The outline of the second recess 21a in plan view may be, for example, circular. However, this is not limiting, and the outline of the second recess 21a in plan view may be, for example, rectangular.

[0033] The second protrusions 21b are arranged in the second recess 21a at intervals in the vertical direction (here, the X-axis direction) and the horizontal direction (here, the Y-axis direction). The second recess 21a and the second protrusions 21b form the second groove 21 in a lattice shape.

[0034] Hereinafter, the region of the fourth surface of the second member 20 where the second groove portion 21 is located will be referred to as the "second groove formation region 120." The second groove formation region 120 constitutes part of the operating region 100. The second member 20 also has a second frame region 220 in the shape of a rectangular frame that surrounds the second groove formation region 120. The second frame region 220 constitutes part of the frame region 200.

[0035] The size of the second groove formation region 120 in the second member 20 is the same as the size of the first groove formation region 110 in the first member 10. In addition, the position of the second groove formation region 120 on the fourth surface of the second member 20 is the same as the position of the first groove formation region 110 on the third surface of the first member 10.

[0036] A heat source is disposed at the center of the lower surface of the second member 20, i.e., the fifth surface located opposite the upper surface of the second member 20.

[0037] In this way, by forming the first groove portion 11 and the second groove portion 21 in a lattice shape, it is possible to efficiently circulate the working fluid in the internal space of the heat dissipation member 1. However, the shapes of the first groove portion 11 and the second groove portion 21 do not necessarily have to be lattice-shaped.

[0038] Two recesses 62 recessed into the fourth surface, which is the upper surface of the second member 20, may be located in the second frame region 220. Two grooves 63 may also be located in the second frame region 220. One end of the grooves 63 opens into the recesses 62, and the other end opens into the second groove formation region 120. The recesses 62 and the grooves 63 form part of the communication passage 60.

[0039] 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, viewed from the positive Z-axis direction side to the negative Z-axis direction.

[0040] As shown in Fig. 4 , the intermediate member 30 may have a third frame region 230 having a rectangular frame shape. The third frame region 230 constitutes a part of the frame region 200. The intermediate member 30 may also have a central portion 32 that is circular in plan view and located inside the third frame region 230, and a plurality of connecting portions 33 that are located between the central portion 32 and the third frame region 230 and connect the central portion 32 and the third frame region 230. In the example shown in Fig. 4 , the central portion 32 may be located at the center of the intermediate member 30. The multiple connecting portions 33 may also be spaced apart from one another and extend radially from the central portion 32 toward the third frame region 230 while increasing in width.

[0041] The intermediate member 30 may further have a plurality of steam holes 36 and a plurality of through holes 37. The plurality of steam holes 36 and the plurality of through holes 37 all penetrate the upper and lower surfaces of the intermediate member 30. The plurality of steam holes 36 function as part of a flow path for vapor of the working fluid. The plurality of steam holes 36 are located between two adjacent connection portions 33. That is, the plurality of steam holes 36 and the plurality of connection portions 33 are located alternately in the circumferential direction. Like the plurality of connection portions 33, the plurality of steam holes 36 are spaced apart from one another and extend radially from the central portion 32 toward the third frame region 230 while increasing in width.

[0042] The plurality of through holes 37 function as part of a flow path for the working fluid. The through holes 37 are minute holes with a smaller opening area than the above-described steam holes 36. Specifically, the through holes 37 are small enough to generate capillary action in the working fluid passing through the through holes 37.

[0043] Two through holes 64 that penetrate the intermediate member 30 in the thickness direction, in this case, the Z-axis direction, may be located in the third frame region 230. The through holes 64 form part of the communication passage 60.

[0044] Fig. 5 is a diagram in which the first groove formation region 110 shown in Fig. 2 and the second groove formation region 120 shown in Fig. 3 are superimposed on the intermediate member 30 shown in Fig. 4. For ease of understanding, the communication passage 60 is omitted from Fig. 5.

[0045] 5 , the first groove formation region 110 and the second groove formation region 120 overlap with the third frame region 230 of the intermediate member 30. In other words, the first groove formation region 110 and the second groove formation region 120 extend outward from the region in which the plurality of steam holes 36 and the plurality of through holes 37 are formed in the intermediate member 30. Hereinafter, the region in which the plurality of steam holes 36 and the plurality of through holes 37 are formed in the intermediate member 30 may be referred to as the "hole formation region."

[0046] In this way, by making the first groove formation region 110 of the first member 10 and the second groove formation region 120 of 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 compared to when the first groove formation region 110 and the second groove formation region 120 are made approximately the same size as the hole formation region.

[0047] The heat source is placed in the center of the heat dissipation member 1. In this case, the temperature of the heat dissipation member 1 decreases the further away from the heat source, i.e., the closer to the outer periphery of the heat dissipation member 1. Furthermore, the vapor of the working fluid condenses into liquid as it moves to the low-temperature region. Therefore, expanding the internal space of the heat dissipation member 1 outward makes it easier for the working fluid to condense.

[0048] Here, an example has been shown in which the first groove formation region 110 and the second groove formation region 120 extend outward from the hole formation region of the intermediate member 30, but this is not limited to this, and the hole formation region of the intermediate member 30 may extend outward from the first groove formation region 110 and the second groove formation region 120.

[0049] The operating region 100 of the heat dissipation member 1 has an internal space sandwiched between a first groove formation region 110 and a second groove formation region 120, and this internal space is filled with hydraulic fluid. Furthermore, an intermediate member 30 is interposed between the first groove formation region 110 and the second groove formation region 120 of the internal space, thereby dividing the operating region 100 into a first space sandwiched between the first groove formation region 110 and the intermediate member 30, and a second space sandwiched between the second groove formation region 120 and the intermediate member 30. These first and second spaces are connected by steam holes 36 and through-holes 37 formed in the intermediate member 30.

[0050] Next, the flow of working fluid in the heat dissipation member 1 according to the embodiment will be described with reference to FIGS. 6 and 7. FIGS. 6 and 7 are diagrams for explaining the flow of working fluid in the heat dissipation member 1 according to the embodiment. Note that FIG. 6 is a diagram in which the third frame region 230 is omitted from the diagram shown in FIG. 5, and FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. 6. In addition, in FIGS. 6 and 7, the flow of steam is indicated by open arrows, and the flow of liquid is indicated by filled arrows.

[0051] The working fluid is heated by the heat source and vaporized into steam. As described above, the heat source is disposed in the center of the underside (fifth surface) of the second member 20 (see FIGS. 1 and 3 ). Therefore, the working fluid vapor is generated in the second space, which is the high-temperature side space where the heat source is disposed, i.e., in the center of the space sandwiched between the second member 20 and the intermediate member 30.

[0052] The vapor of the working fluid passes through the second groove portion 21 of the second groove formation region 120, diffusing in the in-plane direction of the heat dissipation member 1, specifically in the XY plane direction (see the white arrows in Figure 6), and moves through the multiple steam holes 36 to the first space, which is the upper low-temperature space, i.e., the space sandwiched between the first member 10 and the intermediate member 30 (see the white arrows in Figure 7).

[0053] The vapor that has moved to the first space condenses and becomes liquid due to a decrease in temperature. The liquefied working fluid moves through the first groove formation region 110 toward the center of the heat dissipation member 1 due to the capillary force of the first groove portion 11 (see the black arrows in FIG. 6 ). During this process, the working fluid enters the through-holes 37 and is returned to the second space due to the capillary force of the through-holes 37 (see the black arrows in FIG. 7 ). The working fluid that has returned to the second space moves through the second groove formation region 120 toward the center of the heat dissipation member 1 due to the capillary force of the second groove portion 21. By repeating the above cycle, the heat dissipation member 1 can transfer heat from the heat source.

[0054] Next, the specific configurations of the second groove portion 21 formed in the second member 20 and the first groove portion 11 formed in the first member 10 will be described with reference to Fig. 8 and Fig. 9. Fig. 8 is a schematic cross-sectional view showing the configurations of the second groove portion 21 and the first groove portion 11 according to the embodiment. The cross-sectional view shown in Fig. 8 corresponds to an enlarged view of portion G shown in Fig. 7.

[0055] 8, the second groove portion 21 has, on the bottom surface of the second groove portion 21, a plurality of third groove portions 22 that are narrower than the second groove portion 21. The bottom surface of the second groove portion 21 corresponds to the bottom surface of the second recess portion 21a. Therefore, "narrower than the second groove portion 21" means that the width of each of the plurality of third groove portions 22 is smaller than the distance between the plurality of second protrusions 21b located in the second recess portion 21a.

[0056] By providing multiple third grooves 22 on the bottom surface of the second grooves 21, the wettability of the second grooves 21 can be improved compared to when multiple third grooves 22 are not provided. The higher the wettability, the stronger the capillary force. This makes it easier for the working fluid that moves through the second grooves 21 to wet and spread toward the center of the heat dissipation member 1 due to the capillary force of the second grooves 21.

[0057] In this way, according to the heat dissipation member 1, by providing multiple third groove portions 22 on the bottom surface of the second groove portion 21, the circulation efficiency of the working fluid can be increased, and since the heat transfer efficiency is high, the heat dissipation efficiency can be further improved.

[0058] From the viewpoint of further enhancing the wettability of the second groove portion 21, the depth of the third groove portion 22 is preferably about 5 to 100 μm, and the width of the third groove portion 22 is preferably about 5 to 30 μm.

[0059] Furthermore, the first groove portion 11 may have, on the bottom surface of the first groove portion 11, a plurality of fourth groove portions 12 narrower in width than the first groove portion 11. The bottom surface of the first groove portion 11 corresponds to the bottom surface of the first recess portion 11a. Therefore, "narrower in width than the first groove portion 11" means that the width of each of the plurality of fourth groove portions 12 is smaller than the distance between the plurality of first protrusions 11b located in the first recess portion 11a.

[0060] By providing multiple fourth grooves 12 on the bottom surface of the first groove 11, the wettability of the first groove 11 can be improved compared to when multiple fourth grooves 12 are not provided. The higher the wettability, the stronger the capillary force. This makes it easier for the working fluid that moves through the first groove 11 toward the center of the heat dissipation member 1 to wet and spread toward the center of the heat dissipation member 1 due to the capillary force of the first groove 11.

[0061] In this way, by providing a plurality of fourth grooves 12 on the bottom surface of the first groove 11, the circulation efficiency of the working fluid can be increased, and therefore the heat dissipation efficiency can be further improved.

[0062] From the viewpoint of further enhancing the wettability of the first groove portion 11, the depth of the fourth groove portion 12 is preferably about 5 to 100 μm, and the width of the fourth groove portion 12 is preferably about 5 to 30 μm. Furthermore, the fourth groove portion 12 may be omitted as necessary.

[0063] 9 is a schematic plan view showing the configuration of the second groove 21 according to the embodiment, in which the bottom surface of the second groove 21, i.e., the bottom surface of the second recess 21a, is shown.

[0064] 9 , at least one of the plurality of third groove portions 22 extends toward a position corresponding to the heat source HS on the bottom surface of the second groove portion 21. As described above, the heat source HS is disposed in the central portion of the lower surface (fifth surface) of the second member 20 (see FIGS. 1 and 3 ). Therefore, at least one of the plurality of third groove portions 22 extends toward the central portion on the bottom surface of the second groove portion 21 where the heat source HS is disposed.

[0065] For example, five third groove portions 22_1 to 22_5 shown in Fig. 9 out of the plurality of third groove portions 22 extend linearly from the outer periphery of the bottom surface of the second groove portion 21 toward the center of the bottom surface. Furthermore, five third groove portions 22_6 to 22_10 shown in Fig. 9 out of the plurality of third groove portions 22 extend obliquely (here, obliquely at an angle of 45° with respect to the X-axis direction) from the outer periphery of the bottom surface of the second groove portion 21 toward the center of the bottom surface.

[0066] In this way, at least one third groove portion 22 extends toward a position corresponding to the heat source HS on the bottom surface of the second groove portion 21, so that the working fluid can be quickly guided toward the heat source HS by the capillary force of the at least one third groove portion 22. As a result, the circulation efficiency of the working fluid can be increased, and the heat dissipation efficiency can be further improved.

[0067] Next, we will explain one example of a method for manufacturing the above-mentioned heat dissipation member 1. First, using raw materials for the first member 10, the second member 20, and the intermediate member 30, green sheets are formed by a doctor blade method, a roll compaction method, or the like, and a plurality of green sheets are stacked to obtain a laminate.

[0068] Next, the resulting laminate is subjected to laser processing or die punching to obtain molded articles of the first member 10, the second member 20, and the intermediate member 30. For example, by performing laser processing on the resulting laminate, a molded article of the intermediate member 30 can be obtained, in which a through hole 64, a plurality of steam holes 36, and a plurality of through holes 37 are formed. Furthermore, by performing laser processing on the resulting laminate, a molded article of the first member 10 can be obtained, in which a through hole 61 and a first groove portion 11 are formed. This laser processing can form a plurality of fourth groove portions 12 on the bottom surface of the first groove portion 11. Furthermore, by performing laser processing on the resulting laminate, a molded article of the second member 20 can be obtained, in which a recess 62, a groove portion 63, and a second groove portion 21 are formed. This laser processing can form a plurality of third groove portions 22 on the bottom surface of the second groove portion 21. Furthermore, by adjusting the output and wavelength band during laser processing, the width and depth of the fourth groove portion 12 and the third groove portion 22 can be adjusted. In addition, in laser processing, the width and depth of the fourth groove portion 12 and the third groove portion 22 can also be adjusted by adjusting the scanning speed and width of the laser light.

[0069] Next, the compacts of the first member 10, the second member 20, and the intermediate member 30 are stacked in the order of the second member 20, the intermediate member 30, and the first member 10, and then fired to obtain a sintered body of the container 2 in which the first member 10, the second member 20, and the intermediate member 30 are integrated. In this manner, the first member 10, the second member 20, and the intermediate member 30 are integrally molded. Therefore, since adhesives or the like are not required, a highly reliable heat dissipation member 1 can be obtained.

[0070] The method for obtaining each of the molded bodies of the first member 10, the second member 20, and the intermediate member 30 is not limited to the above-described method, and each molded body may be obtained, for example, by processing green sheets and then stacking the green sheets. In the above example, each of the molded bodies of the first member 10, the second member 20, and the intermediate member 30 is produced individually and then stacked to obtain the molded body of the container 2, but the molded body of the container 2 may also be obtained, for example, by sequentially stacking processed green sheets.

[0071] Next, for example, working fluid is injected into the sintered body through one of the two communication paths 60. As the working fluid is injected, gas present inside the sintered body is discharged to the outside through the other of the two communication paths 60. The gas present inside the sintered body may also be degassed using a pump or the like.

[0072] Next, the two communication paths 60 are closed using the sealing member 5 and adhesive, thereby completing the heat dissipation member 1.

[0073] Alternative Embodiment 1 Fig. 10 is a schematic plan view showing the configuration of second groove portion 21 according to Alternative Embodiment 1. Fig. 10 shows the bottom surface of second groove portion 21, i.e., the bottom surface of second recess 21a.

[0074] 10 , at least one third groove portion 22_11 among the plurality of third groove portions 22 may have a first portion 22 a and a second portion 22 b continuous with the first portion 22 a. The first portion 22 a extends in the arrangement direction of the plurality of second protrusions 21 b (an example of a first direction, here, the X-axis direction). The second portion 22 b extends in a second direction different from the first direction, that is, a second direction (here, a direction tilted at 45° with respect to the X-axis direction) toward a position corresponding to the heat source HS.

[0075] As described above, at least one third groove 22_11 has a first portion 22a extending in a first direction (here, the X-axis direction) and a second portion 22b extending in a second direction (here, a direction inclined at 45 degrees relative to the X-axis direction) toward a position corresponding to the heat source HS. In other words, at least one third groove 22_11 is bent toward the position corresponding to the heat source HS. With this configuration, the capillary force of the at least one third groove 22_11 can quickly guide the working fluid toward the heat source HS. As a result, the circulation efficiency of the working fluid can be increased, thereby further improving heat dissipation efficiency.

[0076] Alternative Embodiment 2 Fig. 11 is a schematic plan view showing the configuration of a second groove portion 21 according to Alternative Embodiment 2. Fig. 11 shows the bottom surface of the second groove portion 21, i.e., the bottom surface of the second recess 21a.

[0077] 11 , at least one third groove portion 22_11 of the plurality of third groove portions 22 may merge with another third groove portion 22_12 different from the third groove portion 22_11 at the bottom surface of the second groove portion 21. With this configuration, the working fluid can be quickly guided toward the heat source HS by the capillary force of the at least one third groove portion 22_11 and the other third groove portion 22_12. As a result, the circulation efficiency of the working fluid can be increased, and the heat dissipation efficiency can be further improved.

[0078] Alternative Embodiment 3 Fig. 12 is a schematic plan view showing the configuration of second groove portion 21 according to Alternative Embodiment 3. Fig. 12 shows the bottom surface of second groove portion 21, i.e., the bottom surface of second recess 21a.

[0079] 12 , the third groove portions 22 may have groove groups 22c formed by arranging pairs of two V-shaped intersecting grooves 22c1, 22c2 along the arrangement direction of the second protrusions 21b (an example of the first direction, here the X-axis direction). This configuration allows the capillary force of the groove groups 22c to quickly guide the working fluid toward the heat source HS. As a result, the circulation efficiency of the working fluid can be increased, further improving heat dissipation efficiency.

[0080] As described above, the thermal device according to the embodiment (for example, the heat dissipation member 1) includes a flat ceramic intermediate member (for example, the intermediate member 30), a first member (for example, the first member 10), and a second member (for example, the second member 20). The intermediate member has a plurality of through holes (for example, the through holes 37) penetrating a first surface (for example, the upper surface) and a second surface (for example, the lower surface) that are located opposite each other. The first member has a first groove (for example, the first groove 11) in a third surface (for example, the lower surface) that faces the first surface of the intermediate member. The second member has a second groove (for example, the second groove 21) in a fourth surface (for example, the upper surface) that faces the second surface of the intermediate member, and a heat source is disposed on a fifth surface (for example, the lower surface) that faces the fourth surface. The first groove portion has a first recess (for example, first recess 11a) recessed relative to the third surface and a plurality of first protrusions (for example, first protrusions 11b) located within the first recess. The second groove portion has a second recess (for example, second recess 21a) recessed relative to the fourth surface and a plurality of second protrusions (for example, second protrusions 21b) located within the second recess. The second groove portion has a plurality of third grooves (for example, third grooves 22) on the bottom surface of the second groove portion that are narrower than the second grooves. This can further improve heat dissipation efficiency.

[0081] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0082] REFERENCE SIGNS LIST 1 heat dissipation member 10 first member 11 first groove portion 11a first recessed portion 11b first convex portion 12 fourth groove portion 20 second member 21 second groove portion 21a second recessed portion 21b second convex portion 22 third groove portion 22a first portion 22b second portion 22c groove group 30 intermediate member 37 through hole HS heat source

Claims

1. A thermal device comprising: a flat ceramic intermediate member having a plurality of through holes penetrating a first surface and a second surface located opposite to each other; a flat ceramic first member having a first groove portion on a third surface facing the first surface of the intermediate member; and a flat ceramic second member having a second groove portion on a fourth surface facing the second surface of the intermediate member, the second member having a fifth surface opposite the fourth surface on which a heat source is disposed; wherein the first groove portion has a first recessed portion recessed into the third surface and a plurality of first protrusions located within the first recessed portion; the second groove portion has a second recessed portion recessed into the fourth surface and a plurality of second protrusions located within the second recessed portion; and the second groove portion has a plurality of third grooves on a bottom surface of the second groove portion that are narrower than the second groove portion.

2. The thermal device according to claim 1, wherein at least one of the plurality of third groove portions extends toward a position on the bottom surface of the second groove portion corresponding to the heat source.

3. The thermal device described in claim 1, wherein the plurality of second protrusions are arranged in the second recess at intervals in a first direction, and at least one of the plurality of third grooves has a first portion extending in the first direction, and a second portion that is continuous with the first portion and extends in the second direction different from the first direction toward a position corresponding to the heat source.

4. A thermal device as described in claim 1, wherein at least one of the plurality of third groove portions merges with another third groove portion different from the third groove portion at the bottom surface of the second groove portion.

5. A thermal device as described in claim 1, wherein the plurality of second protrusions are arranged in the first direction at intervals within the second recess, and the plurality of third grooves have a groove group formed by arranging multiple pairs of two grooves that intersect in a V-shape along the first direction.

6. The thermal device according to claim 1, wherein the first groove portion has a plurality of fourth groove portions on the bottom surface of the first groove portion, the fourth groove portions having a width narrower than that of the first groove portion.

7. The thermal device according to claim 1, further comprising a fluid located in an internal space sandwiched between said first groove portion and said second groove portion.

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