Heat diffusion device and electronic device

Abstract

To provide a heat diffusion device with an excellent effect of reducing a heat source temperature.SOLUTION: A vapor chamber 1, which is one embodiment of a heat diffusion device, comprises: a housing 10 having a first inner surface 11a and a second inner surface 12a facing each other in a thickness direction Z and provided with an internal space; a working medium 20 sealed in the internal space of the housing 10; and a wick 30 arranged in the internal space of the housing 10. The wick 30 includes a first wick 31. The first wick 31 is made of a porous metal, and has a plurality of convex parts 40 or concave parts 45 on a surface on the first inner surface 11a of the housing 10.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a heat spreading device and an electronic device. [Background technology]

[0002] In recent years, the amount of heat generated has increased due to the high integration and high performance of elements. Furthermore, as products become more compact, the heat density increases, making heat dissipation measures important. This situation is particularly evident in the field of mobile devices such as smartphones and tablets. Graphite sheets are often used as thermal management materials, but their heat transport capacity is insufficient, so the use of various thermal management materials is being considered. Among these, the use of vapor chambers, which are planar heat pipes, is being considered as a heat diffusion device that can diffuse heat very effectively.

[0003] The vapor chamber has a structure in which a working medium (also called a working liquid) and a wick that transports the working medium by capillary force are enclosed inside a housing. The working medium absorbs heat from a heat-generating element such as an electronic component in an evaporation section, evaporates in the vapor chamber, moves within the vapor chamber, cools, and returns to its liquid phase. The working medium, which has returned to its liquid phase, moves again to the evaporation section on the heating element side by the capillary force of the wick, cooling the heating element. By repeating this process, the vapor chamber operates autonomously without external power and can diffuse heat two-dimensionally at high speed using the latent heat of evaporation and latent heat of condensation of the working medium.

[0004] Patent Document 1 discloses a vapor chamber having a housing, pillars arranged in the internal space of the housing so as to support the housing from the inside, a working fluid sealed in the internal space of the housing, and a wick arranged in the internal space of the housing, wherein at least a portion of the main inner surface of the housing is exposed to the internal space of the housing and has pores with an average depth of 10 nm or more. Patent Document 1 also describes that the wick can be made of, for example, a porous body, a mesh, a sintered body, a nonwoven fabric, or a wire.

[0005] Patent document 2 discloses a heat diffusion device comprising a housing having a first inner wall surface and a second inner wall surface that face each other in the thickness direction, a working medium sealed in the internal space of the housing, and a wick structure disposed in the internal space of the housing, wherein the wick structure includes a support portion that contacts the first inner wall surface and a perforated portion that is made of the same material as the support portion and is integrally formed with the support portion. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-189349 [Patent Document 2] International Publication No. 2023 / 090265 Summary of the Invention [Problem to be solved by the invention]

[0007] Heat diffusion devices such as vapor chambers are sometimes used in high-input ranges where the heat input exceeds several tens of watts or even 100 W. Therefore, the wick located in the evaporation section close to the heat source is required to receive as much heat as possible from the heat source, transfer as much heat as possible to the working medium, and evaporate as much of the working medium as possible in order to reduce the heat source temperature.

[0008] The present invention has been made to solve the above problems, and aims to provide a heat spreading device that is excellent in reducing the heat source temperature, and also to provide an electronic device equipped with the heat spreading device. [Means for solving the problem]

[0009] The heat diffusion device of the present invention includes a housing having a first inner surface and a second inner surface opposed to each other in a thickness direction and having an internal space, a working medium sealed in the internal space of the housing, and a wick disposed in the internal space of the housing. The wick includes a first wick. The first wick is made of a metal porous body and has a plurality of protrusions or recesses on a surface facing the first inner surface of the housing.

[0010] An electronic device of the present invention includes the heat spreading device of the present invention. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a heat spreading device that is excellent in the effect of reducing the temperature of a heat source, and further, it is possible to provide an electronic device that includes the heat spreading device. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view schematically showing an example of a heat diffusion device of the present invention. [Figure 2] FIG. 2 is an exploded perspective view schematically showing an example of the heat diffusion device of the present invention. [Figure 3] FIG. 3 is an exploded perspective view showing the heat diffusion device shown in FIG. 2, in which the wick is disposed in the internal space of the housing. [Figure 4] 4 is a cross-sectional view of the heat spreading device shown in FIG. 3 taken along line IV-IV. [Figure 5]5A and 5B are cross-sectional views showing an example of a state in which a first wick without a protrusion is disposed near a heat source, respectively, and FIG. 5B is a cross-sectional view showing an example of a state in which a first wick with a protrusion is disposed near a heat source. [Figure 6] Fig. 6A is a perspective view schematically showing the first wick according to the first embodiment, and Fig. 6B is a cross-sectional view schematically showing the first wick according to the first embodiment. [Figure 7] Fig. 7A is a perspective view schematically showing the first wick according to the first embodiment as seen from the opposite side to Fig. 6A. Fig. 7B is a cross-sectional view schematically showing the first wick according to the first embodiment as seen from the opposite side to Fig. 6B. [Figure 8] Fig. 8A is a perspective view schematically showing a first wick according to the second embodiment, and Fig. 8B is a cross-sectional view schematically showing the first wick according to the second embodiment. [Figure 9] Fig. 9A is a perspective view schematically showing the first wick according to the second embodiment as seen from the opposite side to Fig. 8A, and Fig. 9B is a cross-sectional view schematically showing the first wick according to the second embodiment as seen from the opposite side to Fig. 8B. [Figure 10] Fig. 10A is a perspective view schematically showing a first wick according to the third embodiment, and Fig. 10B is a plan view schematically showing the first wick according to the third embodiment. [Figure 11] Fig. 11A is a perspective view schematically showing the cross-sectional shape of a first wick according to Embodiment 3. Fig. 11B is a cross-sectional view schematically showing the cross-sectional shape of a first wick according to Embodiment 3. [Figure 12] Fig. 12A is a perspective view schematically showing the cross-sectional shape of the first wick according to the third embodiment as seen from the opposite side to Fig. 11A. Fig. 12B is a cross-sectional view schematically showing the cross-sectional shape of the first wick according to the third embodiment as seen from the opposite side to Fig. 11B. [Figure 13] Fig. 13A is a perspective view schematically showing a first wick according to the fourth embodiment, and Fig. 13B is a plan view schematically showing the first wick according to the fourth embodiment. [Figure 14]Fig. 14A is a perspective view schematically showing the cross-sectional shape of a first wick according to Embodiment 4. Fig. 14B is a cross-sectional view schematically showing the cross-sectional shape of a first wick according to Embodiment 4. [Figure 15] Fig. 15A is a perspective view schematically showing a first wick according to Embodiment 5. Fig. 15B is a plan view schematically showing the first wick according to Embodiment 5. [Figure 16] Fig. 16A is a perspective view schematically showing the cross-sectional shape of a first wick according to Embodiment 5. Fig. 16B is a cross-sectional view schematically showing the cross-sectional shape of a first wick according to Embodiment 5. [Figure 17] Fig. 17A is a perspective view schematically showing a first wick according to Embodiment 6. Fig. 17B is a cross-sectional view schematically showing the first wick according to Embodiment 6. [Figure 18] Fig. 18A is a perspective view schematically showing the first wick according to the sixth embodiment as seen from the opposite side to Fig. 17A. Fig. 18B is a cross-sectional view schematically showing the first wick according to the sixth embodiment as seen from the opposite side to Fig. 17B. [Figure 19] Fig. 19A is a perspective view schematically showing a first wick according to the seventh embodiment, and Fig. 19B is a cross-sectional view schematically showing the first wick according to the seventh embodiment. [Figure 20] Fig. 20A is a perspective view schematically showing the first wick according to the seventh embodiment as seen from the opposite side to Fig. 19A. Fig. 20B is a cross-sectional view schematically showing the first wick according to the seventh embodiment as seen from the opposite side to Fig. 19B. [Figure 21] FIG. 21 is an exploded perspective view schematically showing another example of the heat spreading device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] The heat spreading device of the present invention will now be described. However, the present invention is not limited to the following embodiments and can be appropriately modified and applied within the scope of the present invention. Note that the present invention also includes a combination of two or more of the individual preferred configurations of the present invention described below.

[0014] A vapor chamber will be described below as an example of one embodiment of the heat diffusion device of the present invention. The heat diffusion device of the present invention can also be applied to heat diffusion devices such as heat pipes.

[0015] The drawings shown below are schematic diagrams, and the dimensions, aspect ratio, and other scales may differ from those of the actual product. In the drawings, the same or equivalent parts will be designated by the same reference numerals. In addition, the same elements will be designated by the same reference numerals in each drawing, and duplicate explanations will be omitted.

[0016] In this specification, terms indicating the relationship between elements (e.g., "perpendicular," "parallel," "orthogonal," etc.) and terms indicating the shapes of elements are not expressions that only express a strict meaning, but are expressions that mean that a range of substantial equivalence, for example, a difference of about a few percent, is included. Furthermore, in this specification, "same" or "constant" is not an expression that means only when something is completely the same or constant, but is an expression that means that when something is substantially the same or constant, a difference of about a few percent, for example, is included.

[0017] Fig. 1 is a perspective view schematically showing an example of a heat diffusing device of the present invention. Fig. 2 is an exploded perspective view schematically showing an example of a heat diffusing device of the present invention. Fig. 3 is an exploded perspective view showing the heat diffusing device shown in Fig. 2, in which a wick is disposed in the internal space of a housing.

[0018] The vapor chamber (heat diffusion device) 1 shown in FIG. 1 includes a hollow housing 10 that is sealed in an airtight state. As shown in FIG. 2, the housing 10 has a first inner surface 11a and a second inner surface 12a that face each other in the thickness direction Z. The housing 10 has an internal space. The vapor chamber 1 further includes a working medium 20 sealed in the internal space of the housing 10, and a wick 30 disposed in the internal space of the housing 10. Although not shown, the vapor chamber 1 may further include a support pillar disposed in the internal space of the housing 10.

[0019] As shown in FIG. 1, the housing 10 is provided with an evaporation portion EP that evaporates the enclosed working medium 20 (see FIG. 2). As shown in FIG. 2, a heat source HS, which is a heat generating element, is disposed on the outer surface of the housing 10. Examples of the heat source HS include electronic components of electronic devices, such as a central processing unit (CPU). The portion of the interior space of the housing 10 that is near the heat source HS and that is heated by the heat source HS corresponds to the evaporation portion EP.

[0020] The vapor chamber 1 is preferably planar as a whole. That is, the housing 10 is preferably planar as a whole. Here, "planar" includes plate-like and sheet-like shapes, and refers to a shape in which the dimension in the width direction X (hereinafter referred to as width) and the dimension in the length direction Y (hereinafter referred to as length) are considerably larger than the dimension in the thickness direction Z (hereinafter referred to as thickness or height), for example, a shape in which the width and length are 10 times or more, preferably 100 times or more, the thickness.

[0021] The size of the vapor chamber 1, i.e., the size of the housing 10, is not particularly limited. The width and length of the vapor chamber 1 can be set appropriately depending on the application. The width and length of the vapor chamber 1 are, for example, 5 mm to 500 mm, 20 mm to 300 mm, or 50 mm to 200 mm, respectively. The width and length of the vapor chambers 1 may be the same or different.

[0022] The housing 10 is preferably made up of a first sheet 11 and a second sheet 12 facing each other and joined at their outer edges.

[0023] When the housing 10 is composed of the first sheet 11 and the second sheet 12, the material that makes up the first sheet 11 and the second sheet 12 is not particularly limited as long as it has properties suitable for use as a heat diffusion device such as a vapor chamber, such as thermal conductivity, strength, flexibility, and the like. The material that makes up the first sheet 11 and the second sheet 12 is preferably a metal, such as copper, nickel, aluminum, magnesium, titanium, iron, or an alloy containing these as a main component, with copper being particularly preferred. The materials that make up the first sheet 11 and the second sheet 12 may be the same or different, but are preferably the same.

[0024] When the housing 10 is composed of the first sheet 11 and the second sheet 12, the first sheet 11 and the second sheet 12 are joined to each other at their outer edges. The joining method is not particularly limited, but may be, for example, laser welding, resistance welding, diffusion bonding, brazing, TIG welding (tungsten-inert gas welding), ultrasonic bonding, or resin sealing, and preferably, laser welding, resistance welding, or brazing can be used.

[0025] The thickness of the first sheet 11 and the second sheet 12 is not particularly limited, but is preferably 10 μm or more and 200 μm or less, more preferably 30 μm or more and 100 μm or less, and even more preferably 40 μm or more and 60 μm or less. The thickness of the first sheet 11 and the second sheet 12 may be the same or different. Furthermore, the thickness of each of the first sheet 11 and the second sheet 12 may be the same throughout, or may be thinner in some areas.

[0026] There are no particular limitations on the shapes of the first sheet 11 and the second sheet 12. For example, the first sheet 11 and the second sheet 12 may each have a shape in which the outer edge is thicker than the rest of the sheet.

[0027] The thickness of the entire vapor chamber 1 is not particularly limited, but is preferably 50 μm or more and 500 μm or less. The height of the internal space of the housing 10 is not particularly limited, but is preferably 30 μm or more and 400 μm or less.

[0028] The planar shape of the housing 10 as viewed from the thickness direction Z is not particularly limited, and examples thereof include polygons such as triangles and rectangles, circles, ellipses, and shapes combining these. The planar shape of the housing 10 may also be L-shaped, C-shaped, stepped, or the like. The housing 10 may also have a through-hole. The planar shape of the housing 10 may be a shape that corresponds to the application of the heat diffusion device such as a vapor chamber, the shape of the location where the heat diffusion device is installed, and other components present nearby.

[0029] Although not shown, a support pillar in contact with the first inner surface 11a may be arranged in the internal space of the housing 10. By arranging a support pillar in the internal space of the housing 10, it is possible to support the housing 10 and the wick 30.

[0030] The material constituting the support is not particularly limited, but examples thereof include resin, metal, ceramic, or a mixture or laminate thereof. The support may be integral with the housing 10, and may be formed, for example, by etching the first inner surface 11a of the housing 10.

[0031] The shape of the support pillar is not particularly limited as long as it can support the housing 10 and the wick 30, but examples of the cross-sectional shape perpendicular to the height direction of the support pillar include polygons such as rectangles, circles, ellipses, etc.

[0032] The support pillars may have a tapered shape that narrows from the first inner surface 11a of the housing 10 toward the wick 30. This allows the flow path between the support pillars to be wider on the wick 30 side.

[0033] When multiple support columns are arranged in the internal space of the housing 10, the heights of the support columns may be the same or different within one vapor chamber. The height of the support columns is, for example, 50 μm or more and 1000 μm or less.

[0034] The arrangement of the support posts is not particularly limited, but they are preferably arranged evenly in a predetermined region, more preferably evenly throughout, for example, so that the center-to-center distance (pitch) between adjacent support posts is constant. By arranging the support posts evenly, uniform strength can be ensured throughout the heat diffusion device, such as a vapor chamber. The center-to-center distance of the support posts is, for example, 100 μm or more and 5000 μm or less.

[0035] The width of the support is not particularly limited as long as it provides strength sufficient to suppress deformation of the casing 10, but the equivalent circle diameter of a cross section perpendicular to the height direction of the end of the support on the wick 30 side is, for example, 100 μm or more and 2000 μm or less, and preferably 300 μm or more and 1000 μm or less. Increasing the equivalent circle diameter of the support can further suppress deformation of the casing 10. On the other hand, decreasing the equivalent circle diameter of the support can ensure a larger space for the movement of vapor of the working medium 20.

[0036] The working medium 20 is not particularly limited as long as it can undergo a gas-liquid phase change in the environment inside the housing 10, and examples of the working medium that can be used include water, alcohols, and alternatives to chlorofluorocarbons. For example, the working medium 20 is an aqueous compound, and is preferably water.

[0037] The wick 30 has a capillary structure that allows the working medium 20 to move by capillary force.

[0038] The wick 30 includes a primary wick 31 .

[0039] The first wick 31 is preferably disposed in a region overlapping with the evaporation section EP of the housing 10 (see FIG. 1) in the thickness direction Z. In this case, it is sufficient that at least a portion of the first wick 31 overlaps with at least a portion of the evaporation section EP of the housing 10 in the thickness direction Z. For example, the entire first wick 31 may overlap with at least a portion of the evaporation section EP of the housing 10 in the thickness direction Z, or at least a portion of the first wick 31 may overlap with the entire evaporation section EP of the housing 10 in the thickness direction Z.

[0040] The first wick 31 is preferably arranged in a region that overlaps with the heat source HS (see FIG. 2) in the thickness direction Z. In this case, it is sufficient that at least a portion of the first wick 31 overlaps with at least a portion of the heat source HS in the thickness direction Z. For example, the entire first wick 31 may overlap with at least a portion of the heat source HS in the thickness direction Z, or at least a portion of the first wick 31 may overlap with the entire heat source HS in the thickness direction Z.

[0041] The wick 30 preferably further includes a sheet-like second wick 32 that is arranged throughout the entire interior space of the housing 10. The second wick 32 may also be arranged in only a portion of the interior space of the housing 10.

[0042] 4 is a cross-sectional view of the heat spreading device shown in FIG. 3 taken along line IV-IV.

[0043] Although the overall configuration is not shown in Figure 4, the first wick 31 is made of a porous metal body and has multiple protrusions 40 on the surface (upper surface in Figure 4) facing the first inner surface 11a (see Figure 2) of the housing 10.

[0044] The material constituting the first wick 31 is a metal such as copper, nickel, aluminum, magnesium, titanium, iron, or an alloy containing any of these as a main component, and is preferably copper. The material constituting the first wick 31 may be the same as or different from the material constituting the housing 10.

[0045] The metal porous body constituting the first wick 31 is preferably a metal sintered body or a metal nonwoven fabric. Alternatively, the metal porous body constituting the first wick 31 may be a metal mesh. On the other hand, the metal porous body constituting the first wick 31 does not include pressed metal foil or metal plate. In particular, the first wick 31 is preferably made of a metal sintered body, and more preferably made of a copper sintered body.

[0046] 5A and 5B are cross-sectional views showing an example of a state in which a first wick without a protrusion is disposed near a heat source, respectively, and FIG. 5B is a cross-sectional view showing an example of a state in which a first wick with a protrusion is disposed near a heat source.

[0047] For example, the first wick 31a shown in Fig. 5A and the first wick 31 shown in Fig. 5B are both made of a metal sintered body. When the first wick 31a or the first wick 31 is made of a metal porous body such as a metal sintered body, the contact area with the second inner surface 12a of the housing 10 can be made large, thereby increasing the amount of heat input to the wick 30 (see Fig. 2).

[0048] In the first wick 31a shown in Figure 5A and the first wick 31 shown in Figure 5B, heat received from the heat source HS is transferred to the working medium 20 (see Figure 2) and dissipated into the vapor space within the housing 10 by the vapor generated.

[0049] However, in the first wick 31a shown in Figure 5A, if the dissipation capacity of the working medium 20 vapor from the wick 30 does not exceed the heat input capacity from the heat source HS to the wick 30, the amount of heat input to the wick 30 will not increase as a result.

[0050] In contrast, the first wick 31 shown in FIG. 5B has multiple protrusions 40 on the surface (the upper surface in FIG. 5B) on the first inner surface 11a (see FIG. 2) side of the housing 10, thereby increasing the surface area from which the vapor of the working medium 20 evaporates. This increases the amount of evaporation of the working medium 20 compared to the first wick 31a shown in FIG. 5A. As a result, heat retention is reduced, in other words, thermal resistance is reduced, thereby increasing the effect of reducing the heat source temperature.

[0051] The method for producing the first wick 31 is not particularly limited, but examples include a method in which a metal sintered body such as a copper sintered body is press-molded from the front and back sides using a mold having an uneven shape, thereby transferring the uneven shape of the mold to the surface of the metal sintered body.

[0052] The thickness of the first wick 31 may be uniform throughout. For example, the thickness of the first wick 31 can be made uniform by manufacturing the first wick 31 by press molding. When the thickness of the first wick 31 is uniform, the working medium 20 spreads uniformly in the surface direction of the first wick 31.

[0053] 4, the first wick 31 has a plurality of recesses 50 on the surface facing the second inner surface 12a of the housing 10. As a result, a hollow portion 60 may be formed between the surface of the first wick 31 and the second inner surface 12a of the housing 10.

[0054] Fig. 6A is a perspective view schematically showing a first wick according to the first embodiment. Fig. 6B is a cross-sectional view schematically showing a first wick according to the first embodiment. Fig. 7A is a perspective view schematically showing a first wick according to the first embodiment as seen from the opposite side to Fig. 6A. Fig. 7B is a cross-sectional view schematically showing a first wick according to the first embodiment as seen from the opposite side to Fig. 6B.

[0055] The first wick 31A shown in Figures 6A, 6B, 7A and 7B, when placed in the internal space of the housing 10, has multiple convex portions 40 on its surface facing the first inner surface 11a of the housing 10, and multiple concave portions 50 on its surface facing the second inner surface 12a of the housing 10.

[0056] In the first wick 31A, the recesses 50 on the second inner surface 12a side are preferably located on the opposite side to the protrusions 40 on the first inner surface 11a side.

[0057] Fig. 8A is a perspective view schematically showing a first wick according to a second embodiment. Fig. 8B is a cross-sectional view schematically showing a first wick according to a second embodiment. Fig. 9A is a perspective view schematically showing a first wick according to a second embodiment as seen from the opposite side to Fig. 8A. Fig. 9B is a cross-sectional view schematically showing a first wick according to a second embodiment as seen from the opposite side to Fig. 8B.

[0058] The first wick 31B shown in Figures 8A, 8B, 9A and 9B, when placed in the internal space of the housing 10, has multiple recesses 45 on its surface facing the first inner surface 11a of the housing 10 and multiple protrusions 55 on its surface facing the second inner surface 12a of the housing 10.

[0059] In the first wick 31B, the convex portion 55 on the second inner surface 12a side is preferably located on the opposite side to the concave portion 45 on the first inner surface 11a side.

[0060] FIG. 10A is a perspective view schematically showing a first wick according to a third embodiment. FIG. 10B is a plan view schematically showing a first wick according to a third embodiment. FIG. 11A is a perspective view schematically showing a cross-sectional shape of a first wick according to a third embodiment. FIG. 11B is a cross-sectional view schematically showing a cross-sectional shape of a first wick according to a third embodiment. FIG. 12A is a perspective view schematically showing a cross-sectional shape of a first wick according to a third embodiment as seen from the opposite side to FIG. 11A. FIG. 12B is a cross-sectional view schematically showing a cross-sectional shape of a first wick according to a third embodiment as seen from the opposite side to FIG. 11B.

[0061] The first wick 31C shown in Figures 10A, 10B, 11A, 11B, 12A and 12B, when placed in the internal space of the housing 10, has multiple recesses 45 on its surface facing the first inner surface 11a of the housing 10 and multiple protrusions 55 on its surface facing the second inner surface 12a of the housing 10.

[0062] In the first wick 31C, the convex portion 55 on the second inner surface 12a side is preferably located on the opposite side to the concave portion 45 on the first inner surface 11a side.

[0063] In the first wick 31C, the planar shape of the recess 45 on the first inner surface 11a side is hexagonal in the plan view shown in FIG. 10B.

[0064] The first wick 31C preferably further has a plurality of recesses 50 on the surface thereof facing the second inner surface 12a of the housing .

[0065] The first wick 31C may further have a plurality of protrusions on the surface on the first inner surface 11a side of the housing 10. The protrusions on the first inner surface 11a side are preferably located on the opposite side to the recesses 50 on the second inner surface 12a side.

[0066] In the first wick 31C, the planar shape of the recesses 50 on the second inner surface 12a side is hexagonal. The area of ​​the recesses 50 on the second inner surface 12a side is preferably the same as the area of ​​the recesses 45 on the first inner surface 11a side. Furthermore, the depth of the recesses 50 on the second inner surface 12a side is preferably the same as the depth of the recesses 45 on the first inner surface 11a side.

[0067] Fig. 13A is a perspective view schematically showing a first wick according to a fourth embodiment. Fig. 13B is a plan view schematically showing a first wick according to a fourth embodiment. Fig. 14A is a perspective view schematically showing a cross-sectional shape of a first wick according to a fourth embodiment. Fig. 14B is a cross-sectional view schematically showing a cross-sectional shape of a first wick according to a fourth embodiment.

[0068] The first wick 31D shown in Figures 13A, 13B, 14A and 14B, when placed in the internal space of the housing 10, has multiple recesses 45 on its surface facing the first inner surface 11a of the housing 10 and multiple protrusions 55 on its surface facing the second inner surface 12a of the housing 10.

[0069] In the first wick 31D, the convex portion 55 on the second inner surface 12a side is preferably located on the opposite side to the concave portion 45 on the first inner surface 11a side.

[0070] In the first wick 31D, the planar shape of the recess 45 on the first inner surface 11a side is triangular in the plan view shown in FIG. 13B.

[0071] The first wick 31D preferably further has a plurality of recesses on the surface of the housing 10 facing the second inner surface 12a.

[0072] The first wick 31D may further have a plurality of protrusions on the surface on the first inner surface 11a side of the housing 10. The protrusions on the first inner surface 11a side are preferably located on the opposite side to the recesses on the second inner surface 12a side.

[0073] In the first wick 31D, the planar shape of the recess on the second inner surface 12a side is triangular. The area of ​​the recess on the second inner surface 12a side is preferably the same as the area of ​​the recess 45 on the first inner surface 11a side. Furthermore, the depth of the recess on the second inner surface 12a side is preferably the same as the depth of the recess 45 on the first inner surface 11a side.

[0074] Fig. 15A is a perspective view schematically showing a first wick according to a fifth embodiment. Fig. 15B is a plan view schematically showing a first wick according to a fifth embodiment. Fig. 16A is a perspective view schematically showing a cross-sectional shape of a first wick according to a fifth embodiment. Fig. 16B is a cross-sectional view schematically showing a cross-sectional shape of a first wick according to a fifth embodiment.

[0075] The first wick 31E shown in Figures 15A, 15B, 16A and 16B, when placed in the internal space of the housing 10, has multiple recesses 45 on its surface facing the first inner surface 11a of the housing 10 and multiple protrusions 55 on its surface facing the second inner surface 12a of the housing 10.

[0076] In the first wick 31E, the convex portion 55 on the second inner surface 12a side is preferably located on the opposite side to the concave portion 45 on the first inner surface 11a side.

[0077] In the first wick 31E, the planar shape of the recess 45 on the first inner surface 11a side is quadrangular in the plan view shown in FIG. 15B.

[0078] The first wick 31E preferably further has a plurality of recesses on the surface of the housing 10 facing the second inner surface 12a.

[0079] The first wick 31E may further have a plurality of protrusions on the surface on the first inner surface 11a side of the housing 10. The protrusions on the first inner surface 11a side are preferably located opposite the recesses on the second inner surface 12a side.

[0080] In the first wick 31E, the planar shape of the recess on the second inner surface 12a side is rectangular. The area of ​​the recess on the second inner surface 12a side is preferably the same as the area of ​​the recess 45 on the first inner surface 11a side. Furthermore, the depth of the recess on the second inner surface 12a side is preferably the same as the depth of the recess 45 on the first inner surface 11a side.

[0081] As described above, the planar shape of the recess 45 on the first inner surface 11a side may be a polygon such as a triangle, a rectangle, a pentagon, or a hexagon. In this case, the planar shape of the recess 45 on the first inner surface 11a side may be a regular polygon. Alternatively, the planar shape of the recess 45 on the first inner surface 11a side may be a circle, an ellipse, an oval, or the like.

[0082] Similarly, when recesses 50 are present on the second inner surface 12a side, the planar shape of the recesses 50 on the second inner surface 12a side may be a polygon such as a triangle, a rectangle, a pentagon, or a hexagon. In this case, the planar shape of the recesses 50 on the second inner surface 12a side may be a regular polygon. Alternatively, the planar shape of the recesses 50 on the second inner surface 12a side may be a circle, an ellipse, an oval, or the like. The planar shape of the recesses 50 on the second inner surface 12a side is preferably the same as the planar shape of the recesses 45 on the first inner surface 11a side. In this case, the area of ​​the recesses 50 on the second inner surface 12a side is preferably the same as the area of ​​the recesses 45 on the first inner surface 11a side. Furthermore, the depth of the recesses 50 on the second inner surface 12a side is preferably the same as the depth of the recesses 45 on the first inner surface 11a side.

[0083] Fig. 17A is a perspective view schematically showing a first wick according to a sixth embodiment. Fig. 17B is a cross-sectional view schematically showing a first wick according to a sixth embodiment. Fig. 18A is a perspective view schematically showing a first wick according to a sixth embodiment as seen from the opposite side to Fig. 17A. Fig. 18B is a cross-sectional view schematically showing a first wick according to a sixth embodiment as seen from the opposite side to Fig. 17B.

[0084] The first wick 31F shown in Figures 17A, 17B, 18A and 18B is similar to the first wick 31A shown in Figures 6A, 6B, 7A and 7B in that, when placed in the internal space of the housing 10, it has multiple protrusions 40 on the surface on the first inner surface 11a side of the housing 10.

[0085] On the other hand, the first wick 31F differs from the first wick 31A shown in FIGS. 6A, 6B, 7A, and 7B in that the surface on the second inner surface 12a side of the housing 10 is flat.

[0086] Fig. 19A is a perspective view schematically showing a first wick according to the seventh embodiment. Fig. 19B is a cross-sectional view schematically showing a first wick according to the seventh embodiment. Fig. 20A is a perspective view schematically showing a first wick according to the seventh embodiment as seen from the opposite side to Fig. 19A. Fig. 20B is a cross-sectional view schematically showing a first wick according to the seventh embodiment as seen from the opposite side to Fig. 19B.

[0087] The first wick 31G shown in Figures 19A, 19B, 20A and 20B is similar to the first wick 31C shown in Figures 10A, 10B, 11A, 11B, 12A and 12B in that, when placed in the internal space of the housing 10, it has multiple recesses 45 on the surface facing the first inner surface 11a of the housing 10.

[0088] On the other hand, the first wick 31G differs from the first wick 31C shown in FIGS. 10A, 10B, 11A, 11B, 12A and 12B in that the surface on the second inner surface 12a side of the housing 10 is flat.

[0089] Like the first wicks 31F and 31G, the surface on the second inner surface 12a side of the housing 10 may be flat. In this case, the contact area with the second inner surface 12a of the housing 10 can be increased.

[0090] In the following, the first wicks 31A to 31G will be referred to as the first wick 31 without any distinction being made between them.

[0091] The primary wick 31 is preferably an integral body having a plurality of protrusions 40 or recesses 45. For example, the primary wick 31 is preferably in the shape of a plate or sheet as a whole.

[0092] The shapes, sizes, heights, etc. of the protrusions 40 may be the same as each other, or may be partially or entirely different. Similarly, the shapes, sizes, depths, etc. of the recesses 45 may be the same as each other, or may be partially or entirely different.

[0093] The arrangement of the convex portions 40 or concave portions 45 is not particularly limited, but is preferably arranged evenly in a predetermined area, more preferably evenly throughout, for example so that the center-to-center distance (pitch) between adjacent convex portions 40 or concave portions 45 is constant.

[0094] The center-to-center distance (pitch) between adjacent convex portions 40 or concave portions 45 is not particularly limited, but is, for example, 100 μm or more and 1000 μm or less. If the center-to-center distance (pitch) is too large, it is difficult to increase the surface area of ​​the first wick 31, and if the center-to-center distance (pitch) is too small, it becomes difficult to process the convex portions 40 or concave portions 45.

[0095] The shapes, sizes, heights, etc. of the recesses 50 may be the same as each other, or may be partially or entirely different. Similarly, the shapes, sizes, depths, etc. of the protrusions 55 may be the same as each other, or may be partially or entirely different.

[0096] The arrangement of the recesses 50 or protrusions 55 is not particularly limited, but is preferably arranged evenly in a predetermined area, more preferably evenly throughout, for example so that the center-to-center distance (pitch) between adjacent recesses 50 or protrusions 55 is constant.

[0097] The center-to-center distance (pitch) between adjacent recesses 50 or protrusions 55 is not particularly limited, but is, for example, 100 μm or more and 1000 μm or less. The center-to-center distance (pitch) between adjacent recesses 50 or protrusions 55 may be the same as or different from the center-to-center distance (pitch) between adjacent protrusions 40 or recesses 45.

[0098] The portion of the first wick 31 that contacts the second inner surface 12a of the housing 10 may or may not be bonded to the housing 10.

[0099] When the wick 30 further includes a second wick 32, the size and shape of the second wick 32 are not particularly limited as long as it is sheet-shaped, but for example, it is preferable that the second wick 32 is arranged continuously in the internal space of the housing 10. It is preferable that the second wick 32 is arranged so as not to overlap with the first wick 31 in the thickness direction Z.

[0100] The capillary structure of the secondary wick 32 may be a known structure used in conventional heat diffusion devices.

[0101] The material of the second wick 32 is not particularly limited, and examples thereof include porous metal membranes formed by etching or metal processing, meshes, nonwoven fabrics, sintered bodies, and porous bodies. The mesh that forms the material of the second wick 32 may be, for example, a metal mesh, a resin mesh, or a surface-coated version of such a mesh, and is preferably a copper mesh, a stainless steel (SUS) mesh, or a polyester mesh. The sintered body that forms the material of the second wick 32 may be, for example, a porous metal sintered body, a porous ceramic sintered body, or the like, and is preferably a porous copper or nickel sintered body. The porous body that forms the material of the second wick 32 may be, for example, a porous metal sintered body, a porous ceramic sintered body, or a porous resin sintered body.

[0102] Alternatively, the secondary wick 32 may be a wick structure in which a support portion and a perforated portion made of the same material are integrally formed, as described in International Publication No. 2023 / 090265.

[0103] The thickness of the second wick 32 is not particularly limited, and may be the same as the thickness of the first wick 31, or may be greater than the thickness of the first wick 31, or may be less than the thickness of the first wick 31. The thickness of the second wick 32 may vary in parts.

[0104] The heat spreading device of the present invention is not limited to the above-described embodiment, and various applications and modifications can be made within the scope of the present invention with respect to the configuration of the heat spreading device, manufacturing conditions, etc.

[0105] FIG. 21 is an exploded perspective view schematically showing another example of the heat spreading device of the present invention.

[0106] In the vapor chamber (heat diffusion device) 1A shown in Figure 21, the wick 30A includes only the first wick 31. As shown in Figure 21, the wick 30A may not include the second wick 32 (see Figure 2), and the first wick 31 may be disposed throughout the entire internal space of the housing 10. Note that the first wick 31 may also be disposed in a portion of the internal space of the housing 10.

[0107] When the wick 30A includes only the first wick 31, the size and shape of the first wick 31 are not particularly limited, but it is preferable that the first wick 31 be arranged continuously in the internal space of the housing 10, for example.

[0108] In the heat diffusion device of the present invention, the housing may have one or more evaporation sections, i.e., one or more heat sources may be arranged on the outer wall surface of the housing.

[0109] In the heat diffusion device of the present invention, when the housing has multiple evaporation sections, for example, one first wick may be arranged so as to overlap two or more evaporation sections in the thickness direction of the housing, or separate first wicks may be arranged so as to overlap each evaporation section.

[0110] In the heat spreading device of the present invention, when the housing is composed of a first sheet and a second sheet, the first sheet and the second sheet may overlap so that their edges are aligned, or they may overlap so that their edges are offset.

[0111] In the heat spreading device of the present invention, when the housing is composed of a first sheet and a second sheet, the material constituting the first sheet may be different from the material constituting the second sheet. For example, by using a high-strength material for the first sheet, stress acting on the housing can be dispersed. Furthermore, by using different materials for the first and second sheets, one sheet can have one function and the other sheet can have another function. The above functions are not particularly limited, but include, for example, a heat conduction function and an electromagnetic wave shielding function.

[0112] The heat diffusion device of the present invention can be installed in an electronic device for the purpose of heat dissipation. Therefore, an electronic device equipped with the heat diffusion device of the present invention also constitutes the present invention. Examples of the electronic device of the present invention include smartphones, tablet computers, laptops, game consoles, and wearable devices. As described above, the heat diffusion device of the present invention operates autonomously without requiring external power and can rapidly diffuse heat in two dimensions by utilizing the latent heat of evaporation and latent heat of condensation of the working medium. Therefore, an electronic device equipped with the heat diffusion device of the present invention can effectively dissipate heat within a limited space inside the electronic device.

[0113] The present specification discloses the following:

[0114] <1> a housing having a first inner surface and a second inner surface facing each other in a thickness direction and having an internal space; a working medium sealed in the internal space of the housing; and a wick disposed in the internal space of the housing, The wick includes a first wick, The first wick is a heat diffusion device made of a porous metal body and has a plurality of protrusions or recesses on the surface on the first inner surface side of the housing.

[0115] <2> A hollow portion is formed between the surface of the first wick and the second inner surface of the housing. <1> 2. The heat spreading device according to claim 1 .

[0116] <3> The first wick has a plurality of recesses or protrusions on the surface on the second inner surface side of the housing. <2> 2. The heat spreading device according to claim 1 .

[0117] <4> the recessed portion on the second inner surface side is located opposite to the protruding portion on the first inner surface side, The convex portion on the second inner surface side is located on the opposite side to the concave portion on the first inner surface side. <3> 2. The heat spreading device according to claim 1 .

[0118] <5> The thickness of the first wick is constant. <2> ~ <4> 10. The heat spreading device according to any one of claims 1 to 9.

[0119] <6> The first wick has a flat surface on the second inner surface side of the housing. <1> 2. The heat spreading device according to claim 1 .

[0120] <7> The first wick is disposed in a region overlapping with the evaporation portion of the housing in the thickness direction. <1> ~ <6> 10. The heat spreading device according to any one of claims 1 to 9.

[0121] <8> The wick further includes a sheet-like second wick disposed throughout the interior space of the housing. <7> 2. The heat spreading device according to claim 1 .

[0122] <9> The metal porous body constituting the first wick is a metal sintered body or a metal nonwoven fabric. <1> ~ <8> 10. The heat spreading device according to any one of claims 1 to 9.

[0123] <10> <1> ~ <9> 10. An electronic device comprising the heat spreading device according to any one of claims 1 to 9. [Industrial Applicability]

[0124] The heat spreading device of the present invention can be used in a wide range of applications in the field of mobile information terminals, etc. For example, it can be used to lower the temperature of heat sources such as CPUs and extend the operating time of electronic devices, and can be used in smartphones, tablet terminals, laptop computers, etc. [Explanation of symbols]

[0125] 1. 1A Vapor chamber (heat diffusion device) 10. Cabinet 11 Sheet 1 11a First inner surface 12 Second Sheet 12a Second inner surface 20 Working medium 30, 30A wick 31, 31a, 31A, 31B, 31C, 31D, 31E, 31F, 31G First wick 32 Second Wick 40, 55 convex part 45, 50 recess 60 Hollow part EP evaporation section HS heat source X Width direction Y length direction Z thickness direction

Claims

1. a housing having a first inner surface and a second inner surface facing each other in a thickness direction and having an internal space; a working medium sealed in the internal space of the housing; and a wick disposed in the interior space of the housing, The wick includes a first wick, The first wick is a heat diffusion device made of a porous metal body and has a plurality of protrusions or recesses on the surface on the first inner surface side of the housing.

2. The heat spreading device of claim 1 , wherein a hollow portion is formed between a surface of the first wick and the second inner surface of the housing.

3. The heat spreading device according to claim 2 , wherein the first wick has a plurality of recesses or protrusions on a surface of the housing facing the second inner surface.

4. the recessed portion on the second inner surface side is located opposite to the protruding portion on the first inner surface side, The heat spreading device of claim 3 , wherein the convex portion on the second inner surface side is located opposite the concave portion on the first inner surface side.

5. The heat spreading device of claim 2 , wherein the thickness of the primary wick is constant.

6. The heat spreading device according to claim 1 , wherein the first wick has a flat surface facing the second inner surface of the housing.

7. 7. The heat spreading device according to claim 1, wherein the first wick is disposed in a region overlapping with the evaporation portion of the housing in the thickness direction.

8. The heat spreading device of claim 7 , wherein the wick further comprises a sheet-like second wick disposed throughout the interior space of the housing.

9. 7. The heat diffusion device according to claim 1, wherein the metal porous body constituting the first wick is a metal sintered body or a metal nonwoven fabric.

10. An electronic device comprising the heat spreading device according to any one of claims 1 to 6.

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