Thermal diffusion device and electronic apparatus

Abstract

The utility model relates to a thermal diffusion device and electronic equipment. A vapor chamber as one embodiment of a heat diffusion device is provided with: a housing having first and second inner surfaces facing each other in the thickness direction, and provided with an internal space; a working medium sealed in the internal space; and a first core body and a second core body disposed in the internal space, the first core body including a first through-hole penetrating in the thickness direction, the second core body including a second through-hole penetrating in the thickness direction, and the average pore diameter of the first through-hole being smaller than the average pore diameter of the second through-hole. The area of the planar shape of the first core is smaller than the area of the planar shape of the second core when viewed from the thickness direction, and the first core overlaps the second core in the thickness direction on the second inner surface side. A distance between a portion of the first core closest to the second inner surface in the thickness direction in an edge region of the planar shape of the first core and the first inner surface is smaller than a distance between a portion of the first core closest to the second inner surface in the thickness direction in a region other than the edge region and the first inner surface.

Description

Technical Field

[0001] The present utility model relates to a heat diffusion device and an electronic device. Background Art

[0002] In recent years, due to the high integration and high performance of components, the heat generation has increased. In addition, with the miniaturization of products, the heat generation density has increased, so heat dissipation countermeasures have become important. This situation is particularly significant in the field of mobile terminals such as smartphones and tablet computers. As a heat countermeasure component, a graphite sheet or the like is mostly used, but its heat transfer amount is not sufficient, so the use of various heat countermeasure components has been studied. Among them, as a heat diffusion device that can very effectively diffuse heat, the use of a planar heat pipe, that is, a vapor chamber, is being studied.

[0003] A vapor chamber has a structure in which a working medium (also called a working fluid) is enclosed inside a housing and a core made of a porous body that transports the working medium by capillary force. After the above-mentioned working medium absorbs the heat from a heat generating element such as an electronic component in an evaporation section, evaporates in the vapor chamber, moves in the vapor chamber, is cooled and returns to the liquid phase. The working medium that returns to the liquid phase uses the capillary force of the core to move again to the evaporation section on the heat generating element side and cools the heat generating element. By repeating this operation, the vapor chamber can work independently without an external power source, and using the latent heat of vaporization and latent heat of condensation of the working medium, heat can be diffused two-dimensionally and at high speed.

[0004] In Patent Document 1, a vapor chamber is disclosed, in which a core structure body has: a first core part that extends from a heat receiving part to a heat radiating part and has a first core component using a linear member; and a second core part that is provided in the above-mentioned heat receiving part and has a second core component using a linear member, and the average diameter of the linear member of the second core component is smaller than that of the linear member of the first core component, or the mesh size of the second core component is smaller than that of the first core component.

[0005] Patent Document 1: International Publication No. 2019 / 230385

[0006] In the vapor chamber described in Patent Document 1, in addition to the first core component, a second core component having a higher capillary force is arranged in the heat receiving part. However, when the interface between the second core component and the first core component is not controlled, leakage of the working medium occurs at the gap between the first core component and the second core component, and it is difficult to utilize the high capillary force of the second core component. As a result, there is a problem that the maximum heat transfer amount (Qmax) does not reach the expected level.

[0007] In addition, the above problem is not limited to the vapor chamber, but is a common problem of heat diffusion devices that can diffuse heat through the same structure as the vapor chamber. Summary of the Invention

[0008] The present utility model is completed to solve the above problems, and its object is to provide a heat diffusion device with a large heat transfer amount. In addition, the object of the present utility model is to provide an electronic device equipped with the above heat diffusion device.

[0009] The heat diffusion device of the present utility model includes: a housing having a first inner surface and a second inner surface facing each other in the thickness direction and provided with an internal space; a working medium sealed in the internal space of the housing; and a first core and a second core disposed in the internal space of the housing. The first core includes a first through hole penetrating in the thickness direction, and the second core includes a second through hole penetrating in the thickness direction. The average pore diameter of the first through hole is smaller than the average pore diameter of the second through hole. The area of the planar shape of the first core observed from the thickness direction is smaller than the area of the planar shape of the second core. The first core overlaps the second core in the thickness direction on the second inner surface side. The distance between the portion of the first core closest to the second inner surface in the thickness direction in the edge region of the planar shape of the first core and the first inner surface is smaller than the distance between the portion of the first core closest to the second inner surface in the thickness direction in the region other than the edge region and the first inner surface.

[0010] The electronic device of the present utility model includes the heat diffusion device of the present utility model.

[0011] According to the present utility model, a heat diffusion device with a large heat transfer amount can be provided. In addition, according to the present utility model, an electronic device equipped with the above heat diffusion device can be provided. Brief Description of the Drawings

[0012] Figure 1 FIG. is a perspective view schematically showing an example of the heat diffusion device of the present utility model.

[0013] Figure 2 FIG. schematically shows Figure 1 A top view of an example of the internal structure of the heat diffusion device shown.

[0014] Figure 3 FIG. is Figure 2 A cross-sectional view of the heat diffusion device shown along line A-A.

[0015] Figure 4 FIG. is a cross-sectional view schematically showing an example of the internal structure of the heat diffusion device of the present utility model.

[0016] Figure 5It is a cross-sectional view showing a state where a gap is left between the first core body and the second core body in the edge region of the first core body.

[0017] Figure 6 It is showing Figure 5 a cross-sectional view of a state where there is no gap between the first core body and the second core body in the edge region of

[0018] Figure 7 It is showing Figure 4 a modified example of the heat diffusion device of

[0019] Figure 8 It is a cross-sectional view schematically showing another example of the internal structure of the heat diffusion device of the present utility model.

[0020] Figure 9 It is a cross-sectional view schematically showing another example of the internal structure of the heat diffusion device of the present utility model.

[0021] Figure 10 It is schematically showing Figure 9 a top view of an example of the first core body shown in

[0022] Figure 11 It is a cross-sectional view schematically showing another example of the internal structure of the heat diffusion device of the present utility model.

[0023] Figure 12 It is a cross-sectional view schematically showing another example of the internal structure of the heat diffusion device of the present utility model.

[0024] Figure 13 It is a top view schematically showing an example of the internal structure of a heat diffusion device having a plurality of evaporation portions and a plurality of first core bodies.

[0025] Explanation of reference numerals

[0026] 1, 1A, 2, 3, 4, 5, 6... heat spreader (heat diffusion device); 10... frame; 11... first sheet; 11a... first inner surface; 12... second sheet; 12a... second inner surface; 20, 20A, 20B... first core body; 20A′... first core body before processing; 20a... edge region; 21... first through hole; 24... first convex portion; 25... second convex portion; 30, 30A, 30B, 30C, 30D... second core body; 31... second through hole; 32... etched porous plate; 33... support pillar; 40... working medium; EP... evaporation portion; HS... heat source; X... width direction; Y... length direction; Z... thickness direction. Detailed implementation manners

[0027] Hereinafter, the heat diffusion device of the present utility model will be described.

[0028] However, the present utility model is not limited to the following embodiments and can be appropriately modified and applied within the scope of not changing the gist of the present utility model. In addition, the present utility model also includes combining two or more of the various preferred structures of the present utility model described below.

[0029] Each of the following embodiments is illustrative, and of course, partial replacement or combination of the structures shown in different embodiments can be performed. After the second embodiment, the description of matters common to the first embodiment is omitted, and only the differences are described. In particular, the same effects brought about by the same structure are not mentioned in each embodiment in sequence.

[0030] In the following description, without particularly distinguishing each embodiment, it is simply referred to as "the heat diffusion device of the present utility model".

[0031] Hereinafter, as an embodiment of the heat diffusion device of the present utility model, a vapor chamber is taken as an example for description. The heat diffusion device of the present utility model can also be applied to heat diffusion devices such as heat pipes.

[0032] The following drawings are schematic diagrams, and their dimensions, scales of aspect ratios, etc. may sometimes be different from those of actual products. In the figures, the same or corresponding parts are denoted by the same reference numerals. In addition, in each figure, the same elements are denoted by the same reference numerals and repeated descriptions are omitted.

[0033] In this specification, terms indicating the relationship between elements (such as "vertical", "parallel", "orthogonal", etc.) and terms indicating the shape of elements not only represent strict expressions but also mean substantially the same range, for example, expressions including differences of about a few percent. In addition, in this specification, "equivalent" or "constant" not only represents the case of being completely equivalent or constant but also means the case of being substantially equivalent or constant, for example, expressions including differences of about a few percent.

[0034] The heat diffusion device of the present utility model includes: a housing having a first inner surface and a second inner surface facing each other in the thickness direction and provided with an internal space; a working medium enclosed in the internal space of the housing; and a first core and a second core disposed in the internal space of the housing.

[0035] Hereinafter, with reference to Figure 1 、 Figure 2 and Figure 3 the vapor chamber 1 as the first embodiment of the heat diffusion device of the present utility model will be described.

[0036] Figure 1 is a perspective view schematically showing an example of the heat diffusion device of the present utility model. Figure 2is schematically showing Figure 1 A top view showing an example of the internal structure of the heat diffusion device shown. Figure 3 is Figure 2 A cross-sectional view of the heat diffusion device shown along line A-A.

[0037] Figure 1 The vapor chamber (heat diffusion device) 1 shown includes a hollow frame 10 sealed in an airtight state. As Figure 2 shown, the frame 10 has an evaporation portion (EP) that evaporates the enclosed working medium 40 (refer to Figure 3 ). As Figure 1 shown, a heat source (HS) serving as a heating element is disposed on the outer wall surface of the frame 10. Examples of the heat source HS include electronic components of an electronic device, such as a central processing unit (CPU). In the internal space of the frame 10, the portion near the heat source HS, i.e., the portion heated by the heat source HS, corresponds to the evaporation portion EP.

[0038] For example, as Figure 3 shown, the frame 10 has a first inner surface 11a and a second inner surface 12a that face each other in the thickness direction Z. In this case, the frame 10 is preferably composed of a first sheet 11 and a second sheet 12 that are opposed and joined at their outer edge portions.

[0039] The vapor chamber 1 is preferably planar as a whole. That is, the frame 10 is preferably planar as a whole. Here, "planar" includes plate-like and sheet-like, and refers to a shape in which the dimension in the width direction X (hereinafter referred to as the width) and the dimension in the length direction Y (hereinafter referred to as the length) are considerably larger than the dimension in the thickness direction Z (hereinafter referred to as the thickness or height), for example, a shape in which the width and the length are 10 times or more, preferably 100 times or more, the thickness.

[0040] The size of the vapor chamber 1, that is, the size of the frame 10 is not particularly limited. The width and length of the vapor chamber 1 can be appropriately set according to the use. The width and length of the vapor chamber 1 are, for example, 5 mm or more and 500 mm or less, 20 mm or more and 300 mm or less, or 50 mm or more and 200 mm or less, respectively. The width and length of the vapor chamber 1 may be the same or different.

[0041] In the case where the casing 10 is composed of the first sheet 11 and the second sheet 12, the materials constituting the first sheet 11 and the second sheet 12 are not particularly limited as long as they have properties suitable for use as heat diffusion devices such as heat pipes, for example, thermal conductivity, strength, flexibility, flexibility, etc. The materials constituting the first sheet 11 and the second sheet 12 are preferably metals, such as copper, nickel, aluminum, magnesium, titanium, iron, or alloys mainly composed of them, and particularly preferably copper. The materials constituting the first sheet 11 and the second sheet 12 may be the same or different, but are preferably the same.

[0042] In the case where the casing 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 edge portions. The method of this joining is not particularly limited, and for example, laser welding, resistance welding, diffusion bonding, brazing, TIG welding (tungsten-inert gas welding), ultrasonic bonding, or resin sealing can be used, and laser welding, resistance welding, or brazing is preferably used.

[0043] The thicknesses of the first sheet 11 and the second sheet 12 are not particularly limited, but are respectively preferably 10 μm or more and 200 μm or less, more preferably 30 μm or more and 100 μm or less, and further preferably 40 μm or more and 60 μm or less. The thicknesses of the first sheet 11 and the second sheet 12 may be the same or different. In addition, the thicknesses of each sheet of the first sheet 11 and the second sheet 12 may be the same as a whole, or a part may be thinner.

[0044] The shapes of the first sheet 11 and the second sheet 12 are not particularly limited. For example, the first sheet 11 and the second sheet 12 may each have a shape in which the outer edge portion is thicker than the portion other than the outer edge portion.

[0045] The thickness of the entire heat pipe 1 is not particularly limited, and is preferably 50 μm or more and 500 μm or less.

[0046] The planar shape of the casing 10 as viewed from the thickness direction Z is not particularly limited, and for example, polygons such as triangles or rectangles, circles, ellipses, shapes formed by combining them, etc. can be cited. In addition, the planar shape of the casing 10 may be an L shape, a C shape (コ shape), a stepped shape, etc. In addition, the casing 10 may have a through-hole. The planar shape of the casing 10 may also be a shape corresponding to the use of the heat diffusion device such as a heat pipe, the shape of the installation portion of the heat diffusion device, and other members existing nearby.

[0047] As Figure 3 shown, in the heat pipe 1, the working medium 40 is enclosed in the internal space of the casing 10.

[0048] The working medium 40 is not particularly limited as long as it can cause gas-liquid phase change in the environment within the housing 10. For example, water, alcohols, Freon substitutes, etc. can be used. For example, the working medium is an aqueous compound, preferably water.

[0049] The first core 20 and the second core 30 are disposed in the internal space of the housing 10. The first core 20 and the second core 30 have a capillary structure capable of moving the working medium 40 by capillary force. The first core 20 and the second core 30 are in sheet form.

[0050] As Figure 2 shown, the planar shape of the first core 20 is, for example, a quadrilateral. The planar shape of the first core 20 is not limited to a quadrilateral, and can also be, for example, a triangle, a polygon, a circle, etc.

[0051] The size and shape of the second core 30 are not particularly limited, but for example, it is preferred that the second core 30 is continuously disposed in the internal space of the housing 10.

[0052] The area of the planar shape of the first core 20 as observed from the thickness direction is smaller than the area of the planar shape of the second core 30. For example, the area of the planar shape of the first core 20 is 50 area % or less of the area of the planar shape of the second core 30, and can also be 30 area % or less. For example, the area of the planar shape of the first core 20 is 5 area % or more of the area of the planar shape of the second core 30. As observed from the thickness direction, the first core 20 is disposed at the central portion of the evaporation section EP. As observed from the thickness direction, the first core 20 is preferably disposed so as to overlap at least a part of the evaporation section EP.

[0053] As Figure 3 shown, the first core 20 overlaps the second core 30 in the thickness direction on the side of the second inner surface 12a.

[0054] It is preferred that the distance between the first core 20 and the second inner surface 12a is greater than the distance between the second core 30 and the first inner surface 11a. Since the gaseous working medium 40 moves in the space between the first core 20 and the second inner surface 12a, if the distance between the first core 20 and the second inner surface 12a is large, the moving efficiency of the gaseous working medium 40 is good.

[0055] For the heat pipe 1, Figure 2 and Figure 3The distance between the portion of the first core body 20 closest to the second inner surface 12a in the thickness direction in the edge region 20a of the planar shape of the shown first core body 20 and the first inner surface 11a is smaller than the distance between the portion of the first core body 20 closest to the second inner surface 12a in the thickness direction in the region outside the edge region 20a and the first inner surface 11a. The proportion of the area of the edge region 20a is not particularly limited. For example, it can be 5% or more and 30% or less of the area of the planar shape of the first core body 20.

[0056] Hereinafter, in addition to referring to Figure 2 and Figure 3 also refer to Figure 4 、 Figure 5 and Figure 6 to describe the more detailed internal structure of the heat sink 1.

[0057] Figure 4 is a cross-sectional view schematically showing an example of the internal structure of the heat diffusion device of the present utility model.

[0058] The first core body 20A is composed of an etched porous plate. The etched porous plate forms a plurality of holes (first through holes 21) by performing etching on a flat metal plate. The etched porous plate is not limited to being formed by etching, and as long as it has the same shape, it can also be manufactured by other methods. The same applies to the second core body 30A.

[0059] The second core body 30A is an integral core body in which an etched porous plate 32 and a support pillar 33 for supporting the etched porous plate 32 are integrated.

[0060] The first core body 20A includes first through holes 21 penetrating in the thickness direction. For the first core body 20A, for example, the aperture diameter of the first through holes 21 is constant. The aperture diameter of the first through holes 21 may also become smaller as it approaches the first inner surface 11a, or may become smaller as it approaches the second inner surface 12a.

[0061] The second core body 30A includes second through holes 31 penetrating in the thickness direction. In the second core body 30A, for example, the aperture diameter of the second through holes 31 becomes smaller as it approaches the second inner surface 12a. The aperture diameter of the second through holes 31 may also be constant, or may become smaller as it approaches the first inner surface 11a.

[0062] The average aperture diameter φ1 of the first through holes 21 is smaller than the average aperture diameter φ2 of the second through holes 31. The average aperture diameter φ1 of the first through holes 21 is not particularly limited. For example, it is 5 μm or more and 100 μm or less. The average aperture diameter φ2 of the second through holes 31 is not particularly limited. For example, it is 10 μm or more and 150 μm or less.

[0063] The average pore diameter is calculated by the following method.

[0064] When the pore diameter is constant, an XZ cross-section of the core is photographed using a scanning electron microscope (SEM), and the pore diameters of any 10 through-holes are calculated from the obtained images, and the average value is taken as the average pore diameter.

[0065] When the pore diameter decreases as it approaches the first inner surface or decreases as it approaches the second inner surface, an XZ cross-section of the core is photographed using SEM, and for any 10 through-holes, the maximum pore diameter and the minimum pore diameter are calculated respectively from the obtained images. The value obtained by adding the maximum pore diameter and the minimum pore diameter of the 10 through-holes and dividing by 20 is taken as the average pore diameter.

[0066] The shape of the support pillar 33 is not particularly limited as long as it can support the etched perforated plate 32. Examples of the shape of the cross-section of the support pillar 33 perpendicular to the height direction include polygons such as rectangles, circles, ellipses, etc. As Figure 4 shown, the support pillar 33 is, for example, a tapered shape whose width narrows as it approaches the first inner surface 11a of the frame body 10 from the etched perforated plate 32. Thus, on the first inner surface 11a side, the flow path of the working medium between the support pillars 33 can be enlarged. The width of the support pillar 33 may also be constant, or may be a tapered shape whose width narrows as it approaches the second inner surface 12a.

[0067] The arrangement of the support pillars 33 is not particularly limited. For example, as Figure 2 shown, it is preferable to arrange the support pillars 33 evenly over the entire planar shape of the second core 30A so that, for example, the distance between the support pillars 33 is constant.

[0068] The thickness c1 in the edge region 20a of the first core 20A is smaller than the thickness c2 in the region other than the edge region 20a. Since c1 is smaller than c2, the distance e between the portion of the first core 20A closest to the second inner surface 12a in the thickness direction in the edge region 20a of the first core 20A and the first inner surface 11a is smaller than the sum of the thickness c2 at the portion of the first core 20A closest to the second inner surface 12a in the thickness direction in the region other than the edge region 20a of the first core 20A and the distance d between the portion of the second core 30A closest to the second inner surface 12a in the thickness direction and the first inner surface 11a (c2 + d > e).

[0069] In Figure 4 the first core 20A and the second core 30A are schematically shown as having constant dimensions, but the cores made of etched perforated plates or the like are generally not completely flat as Figure 5 shown (the first core 20A' before processing). Figure 5It is a cross-sectional view showing the state where a gap is left between the first core body and the second core body in the edge region of the first core body. Generally, if only the etched perforated plates are overlapped, a gap is formed between the etched perforated plates.

[0070] In contrast, in the edge region 20a, by bringing the first core body 20A into close contact with the second core body 30A, as Figure 6 shown, the gap between the first core body 20A and the second core body 30A in the edge region 20a is smaller than the gap between the first core body 20A and the second core body 30A in the region other than the edge region 20a. Figure 6 It is a cross-sectional view showing Figure 5 the state where there is no gap between the first core body and the second core body in the edge region of

[0071] The materials constituting the first core body and the second core body are not particularly limited, but metals are preferred, such as copper, nickel, aluminum, magnesium, titanium, iron, or alloys mainly composed of them, and copper is particularly preferred. The material constituting the first core body may be the same as or different from the material constituting the second core body. The material constituting the first core body may be the same as or different from the material constituting the frame body. The material constituting the second core body may be the same as or different from the material constituting the frame body.

[0072] Next, hereinafter, a vapor chamber 1A as a modified example of the vapor chamber 1 will be described. Here, only the parts different from the vapor chamber 1 will be described. Figure 7 It is a cross-sectional view showing a modified example of the heat dissipation device of

[0073] Figure 7 It is a cross-sectional view showing Figure 4 a modified example of

[0074] As Figure 7 shown, the second core body 30B is formed only by the etched perforated plate 32. In the vapor chamber 1A, the support pillar 33 for supporting the etched perforated plate 32 is not integrated with the etched perforated plate 32 and is separated from the second core body 30B, and the support pillar 33 is provided between the second core body 30B and the first inner surface 11a. The etched perforated plate is not limited to being formed by etching, and as long as it has the same shape, it may also be manufactured by other methods.

[0075] In the vapor chamber 1A, the support pillar 33 is preferably arranged at a position and with a size that do not block the holes of the etched perforated plate 32. As Figure 7 shown, the support pillar 33, for example, has a constant width in the height direction. The support pillar 33 may also be in a tapered shape whose width becomes narrower as it approaches the first inner surface 11a, or may be in a tapered shape whose width becomes narrower as it approaches the second inner surface 12a.

[0076] The material forming the support column 33 is not particularly limited, and examples thereof include resin, metal, ceramic, or a mixture or laminate thereof. Further, the support column 33 may be integral with the housing 10. For example, it may be formed by etching the first inner surface 11a of the housing 10 or the like.

[0077] Hereinafter, with reference to Figure 8 the heat dissipation device as a second embodiment of the present utility model, the heat pipe 2 will be described. Here, only the parts different from the heat pipe 1 will be described.

[0078] Figure 8 It is a cross-sectional view schematically showing another example of the internal structure of the heat dissipation device of the present utility model.

[0079] The first core 20A is formed of an etched perforated plate. The aperture of the first through-hole 21 becomes smaller as it approaches the second inner surface 12a. The aperture of the first through-hole 21 may also be constant, or may become smaller as it approaches the first inner surface 11a.

[0080] As Figure 8 shown, the second core 30C is formed of a mesh.

[0081] The mesh may be formed of, for example, a metal mesh, a resin mesh, or these meshes with a surface coating, and is preferably formed of a metal mesh. More preferably, the above-mentioned mesh is formed of a copper mesh or a stainless steel (SUS) mesh.

[0082] Hereinafter, with reference to Figure 9 and Figure 10 the heat dissipation device as a third embodiment of the present utility model, the heat pipe 3 will be described. Here, only the parts different from the heat pipe 2 will be described.

[0083] Figure 9 It is a cross-sectional view schematically showing another example of the internal structure of the heat dissipation device of the present utility model.

[0084] As Figure 9 and Figure 10 shown, the first core 20B is formed of a metal foil having a punching hole (first through-hole 21) in the vertical direction based on stamping. The metal foil having a punching hole in the vertical direction is not limited to being formed by stamping, and may be manufactured by other methods as long as it has the same shape.

[0085] Figure 10 It is a top view schematically showing Figure 9 an example of the first core shown. In addition, Figure 9 shows Figure 10 a cross-section taken along line B-B of the first core 20B shown.

[0086] As shown Figure 9 As shown, a first convex portion 24 protruding in the direction approaching the first inner surface 11a of the housing 10 in the thickness direction Z and a second convex portion 25 protruding in the direction approaching the second inner surface 12a of the housing 10 in the thickness direction Z are provided on the periphery of the first through hole 21. The second convex portion 25 is provided on the periphery of the first through hole 21 on the B-B line. The first convex portion 24 is provided on the periphery of the first through hole 21 adjacent to the first through hole 21 on the B-B line in the length direction Y.

[0087] The thickness c1 in the edge region 20a of the first core body 20B is smaller than the thickness c2 of the first core body 20B in the region other than the edge region 20a. Since the thickness c1 is smaller than the thickness c2, e is smaller than c2 + d.

[0088] Hereinafter, with reference to Figure 11 the heat dissipation device of the fourth embodiment of the present invention, the heat pipe 4 will be described. Here, the parts different from the heat pipe 3 will be described.

[0089] Figure 11 is a cross-sectional view schematically showing another example of the internal structure of the heat dissipation device of the present invention.

[0090] The second core body 30D is an integral core body formed by integrating an etched porous plate 32 and a pillar 33 supporting the etched porous plate 32. The etched porous plate is not limited to being formed by etching, and may be manufactured by other methods as long as it has the same shape.

[0091] For the second core body 30D, for example, the aperture of the second through hole 31 of the etched porous plate 32 is constant. The aperture of the second through hole 31 may also become smaller as it approaches the first inner surface 11a, or may become smaller as it approaches the second inner surface 12a.

[0092] Hereinafter, with reference to Figure 12 the heat dissipation device of the fifth embodiment of the present invention, the heat pipe 5 will be described. Here, the parts different from the heat pipe 3 will be described.

[0093] Figure 12 is a cross-sectional view schematically showing another example of the internal structure of the heat dissipation device of the present invention.

[0094] The first core body 20B, like the heat pipe 3, is formed of a metal foil including punching holes in the up and down directions, but the thickness of the first core body 20B is c2 and constant as a whole.

[0095] The thickness in the edge region 20a of the second core body 30C is smaller than the thickness of the second core body 30C in the region outside the edge region 20a. In the heat pipe 5, since the thickness of the second core body 30C in the edge region 20a is small, e is smaller than c2 + d.

[0096] The heat diffusion device of the present utility model can be manufactured by reducing the thickness of the first core body, the second core body, or both in the edge region of the first core body. The method for reducing the thickness of the first core body, the second core body, or both is not particularly limited, and examples thereof include welding such as laser welding and ultrasonic welding that do not require additional materials, and crimping.

[0097] In the heat diffusion device of the present utility model, the first core body and the second core body are in close contact in the edge region. Therefore, it is considered that leakage of the working medium is not likely to occur at the interface between the first core body and the second core body, and the high capillary force of the second core body can be exerted. When the high capillary force is exerted, as a result, the maximum heat transfer amount (Qmax) of the heat diffusion device is increased.

[0098] [Other Embodiments]

[0099] The heat diffusion device of the present utility model is not limited to the above-described embodiments, and various applications and modifications can be made to the structure, manufacturing conditions, etc. of the heat diffusion device within the scope of the present utility model.

[0100] The combination of the first core body and the second core body is not limited to the above-described embodiments, and the first core body exemplified in one embodiment can be combined with the second core body exemplified in other embodiments.

[0101] The heat diffusion device of the present utility model may be provided with a support column in contact with the first inner surface, or may not be provided with a support column in contact with the first inner surface. The support column in contact with the first inner surface may be integrated with the second core body, may be integrated with the frame body, or may be a component separate from the frame body and the second core body.

[0102] Although not shown in Figure 3 , support columns in contact with the second inner surface 12a side may also be provided in the internal space of the frame body 10. By providing support columns in the internal space of the frame body 10, the frame body 10 can support at least one of the first core body 20 and the second core body 30.

[0103] The material constituting the support column is not particularly limited, and examples thereof include resin, metal, ceramic, or a mixture or laminate thereof. In addition, the support column may be integrated with the frame body 10. For example, it may also be formed by etching the second inner surface 12a of the frame body 10.

[0104] The shape of the support columns is not particularly limited as long as it can support the housing 10, the first core 20, and the second core 30. Examples of the shape of the cross-section of the support columns perpendicular to the height direction include polygons such as rectangles, circles, ellipses, and the like.

[0105] The support columns may also have a tapered shape that narrows in width as it approaches the first core 20 and the second core 30 from the second inner surface 12a of the housing 10. Thereby, on the side of the first core 20 and the second core 30, the flow path between the support columns can be enlarged.

[0106] When the support columns in contact with the second inner surface 12a side are arranged in the internal space of the housing 10, the height of the support columns is, for example, 25 μm or more and 400 μm or less.

[0107] The width of the support columns in contact with the second inner surface 12a side is not particularly limited as long as it provides a strength that can suppress the deformation of the housing 10. However, the equivalent circle diameter of the cross-section perpendicular to the height direction of the end portions of the support columns on the side of the first core 20 and the second core 30 is, for example, 100 μm or more and 2000 μm or less, preferably 300 μm or more and 1000 μm or less. By increasing the equivalent circle diameter of the support columns, the deformation of the housing 10 can be further suppressed. On the other hand, by reducing the equivalent circle diameter of the support columns, a larger space can be ensured for the steam of the working medium 40 to move.

[0108] When a plurality of support columns are arranged in the internal space of the housing 10, the shapes, heights, etc. of the support columns may be the same or different.

[0109] The arrangement of the support columns is not particularly limited, but it is preferably evenly arranged in a specified area, and more preferably evenly arranged throughout. For example, the center-to-center distance (pitch) of adjacent support columns is made constant. By arranging the support columns evenly, a uniform strength can be ensured throughout the heat dissipation device such as a heat pipe. The center-to-center distance of the support columns is, for example, 100 μm or more and 10000 μm or less.

[0110] In the heat dissipation device of the present utility model, the housing may have one evaporation section or a plurality of evaporation sections. That is, one heat source or a plurality of heat sources may be arranged on the outer wall surface of the housing.

[0111] Figure 13 It is a top view schematically showing an example of the internal structure of a heat dissipation device having a plurality of evaporation sections and a plurality of first cores. In Figure 13 In the heat pipe 6 shown, two evaporation sections EP and two first cores 20 are arranged, and evaporation sections EP are provided at positions overlapping the first cores 20 respectively.

[0112] In the heat diffusion device of the present utility model, when the frame body is composed of a first sheet and a second sheet, the first sheet and the second sheet can overlap with their ends aligned, or can overlap with their ends offset.

[0113] In the heat diffusion device of the present utility model, when the frame body is composed of a first sheet and a second sheet, the material constituting the first sheet and the material constituting the second sheet can also be different. For example, by using a material with high strength for the first sheet, the stress applied to the frame body can be dispersed. In addition, by making the materials of the two different, one function can be obtained by one sheet, and other functions can be obtained by the other sheet. The above functions are not particularly limited, and examples thereof include a heat conduction function, an electromagnetic wave shielding function, etc.

[0114] The heat diffusion device of the present utility model can be mounted on an electronic device for the purpose of heat dissipation. Therefore, an electronic device equipped with the heat diffusion device of the present utility model is also one of the present utility models. The electronic device of the present utility model preferably further includes an electronic component, and the above electronic component is disposed on the outer side surface of the frame body on the above first inner surface side.

[0115] Examples of the electronic device of the present utility model include a smart phone, a tablet terminal, a notebook computer, a game console, a wearable device, etc. As described above, the heat diffusion device of the present utility model operates independently without external power, and can diffuse heat two-dimensionally and at high speed by using the latent heat of vaporization and the latent heat of condensation of the working medium. Therefore, an electronic device equipped with the heat diffusion device of the present utility model can effectively achieve heat dissipation in a limited space inside the electronic device.

[0116] In this specification, the following content is disclosed.

[0117] <1>A heat diffusion device, comprising:

[0118] A frame body having a first inner surface and a second inner surface opposed to each other in the thickness direction, and provided with an internal space;

[0119] A working medium sealed in the internal space of the above frame body; and

[0120] A first core body and a second core body disposed in the internal space of the above frame body,

[0121] The above first core body includes a first through hole penetrating along the above thickness direction,

[0122] The above second core body includes a second through hole penetrating along the above thickness direction,

[0123] The average pore diameter of the above first through hole is smaller than the average pore diameter of the above second through hole,

[0124] The area of the planar shape of the first core body as observed in the above thickness direction is smaller than the area of the planar shape of the second core body.

[0125] The first core body overlaps with the second core body in the thickness direction on the second inner surface side.

[0126] The distance between the portion of the first core body closest to the second inner surface in the thickness direction in the edge region of the planar shape of the first core body and the first inner surface is smaller than the distance between the portion of the first core body closest to the second inner surface in the thickness direction in the region outside the edge region and the first inner surface.

[0127] <2> The thermal diffusion device according to <1>.

[0128] The thickness of the first core body in the edge region is smaller than the thickness of the first core body in the region outside the edge region.

[0129] <3> The thermal diffusion device according to <1> or <2>.

[0130] The gap between the first core body and the second core body in the edge region is smaller than the gap between the first core body and the second core body in the region outside the edge region.

[0131] <4> The thermal diffusion device according to any one of <1> to <3>.

[0132] The aperture diameter of the first through hole becomes smaller as it approaches the second inner surface.

[0133] <5> The thermal diffusion device according to any one of <1> to <4>.

[0134] On the periphery of the first through hole, there is a first convex portion protruding in the direction approaching the first inner surface, a second convex portion protruding in the direction approaching the second inner surface, or both.

[0135] <6> The thermal diffusion device according to any one of <1> to <5>.

[0136] The aperture diameter of the second through hole becomes smaller as it approaches the second inner surface.

[0137] <7> The thermal diffusion device according to any one of <1> to <6>.

[0138] The second core body is composed of a metal mesh.

[0139] <8> The thermal diffusion device according to any one of <1> to <7>.

[0140] The above-mentioned housing has an evaporation section for evaporating the above-mentioned working medium, and when viewed from the above-mentioned thickness direction, the above-mentioned first core is arranged to overlap at least a part of the above-mentioned evaporation section.

[0141] <9> According to the heat diffusion device described in <8>,

[0142] The above-mentioned housing has a plurality of the above-mentioned evaporation sections, and the heat diffusion device includes a plurality of the above-mentioned first cores.

[0143] <10> According to the heat diffusion device described in any one of <1> to <9>,

[0144] The distance between the above-mentioned first core and the above-mentioned second inner surface is larger than the distance between the above-mentioned second core and the above-mentioned first inner surface.

[0145] <11> An electronic device,

[0146] includes the heat diffusion device described in any one of <1> to <10>.

[0147] <12> According to the electronic device described in <11>,

[0148] further includes an electronic component,

[0149] The above-mentioned electronic component is arranged on the outer side surface of the housing on the above-mentioned first inner surface side.

[0150] Industrial availability

[0151] The heat diffusion device of the present utility model can be used for a wide range of applications in fields such as portable information terminals. For example, it can be used to reduce the temperature of heat sources such as CPUs and extend the service life of electronic devices, and can be used in smartphones, tablet terminals, laptop computers, etc.

Claims

1. A heat diffusion device, characterized in that: have: The frame has a first inner surface and a second inner surface that are opposite to each other in the thickness direction and is provided with an internal space; A working medium is sealed in the internal space of the frame; and The first core and the second core are arranged in the inner space of the frame. The first core body includes a first through hole penetrating along the thickness direction, The second core body includes a second through hole penetrating along the thickness direction, The average pore size of the first through holes is smaller than the average pore size of the second through holes. The area of ​​the planar shape of the first core observed in the thickness direction is smaller than the area of ​​the planar shape of the second core, The first core overlaps the second core in the thickness direction on the second inner surface side, The distance between the portion of the first core closest to the second inner surface in the thickness direction in the edge area of ​​the planar shape of the first core and the first inner surface is smaller than the distance between the portion of the first core closest to the second inner surface in the thickness direction in the area outside the edge area and the first inner surface.

2. The heat diffusion device according to claim 1, characterized in that: The thickness of the first core in the edge region is smaller than the thickness of the first core in a region other than the edge region.

3. The heat diffusion device according to claim 1, characterized in that: A gap between the first core and the second core in the edge region is smaller than a gap between the first core and the second core in a region other than the edge region.

4. The heat diffusion device according to claim 1, characterized in that: The diameter of the first through hole decreases toward the second inner surface.

5. The heat diffusion device according to claim 1, characterized in that: At least one of a first convex portion protruding in a direction approaching the first inner surface and a second convex portion protruding in a direction approaching the second inner surface is provided on a periphery of the first through hole.

6. The heat diffusion device according to claim 1, characterized in that The diameter of the second through hole decreases toward the second inner surface.

7. The heat diffusion device according to claim 1, characterized in that The second core is made of a metal mesh.

8. The heat diffusion device according to claim 1, characterized in that The frame has an evaporation portion that evaporates the working medium, and the first core is arranged to overlap at least a portion of the evaporation portion when viewed in the thickness direction.

9. The heat diffusion device according to claim 8, characterized in that The frame has a plurality of the evaporation parts, and the thermal diffusion device includes a plurality of the first cores.

10. The heat diffusion device according to claim 1, characterized in that The distance between the first core and the second inner surface is greater than the distance between the second core and the first inner surface.

11. An electronic device, characterized in that: The electronic device comprises the heat diffusion device according to any one of claims 1 to 10.

12. The electronic device according to claim 11, characterized in that: It also has electronic components. The electronic component is disposed on an outer surface of the housing on the first inner surface side.

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