Wick for thermal diffusion device, thermal diffusion device, and electronic apparatus

Abstract

To provide a wick for a thermal diffusion device capable of achieving both of transport performance for working fluid and passage diffusivity for vapor.SOLUTION: A wick 30 for a thermal diffusion device comprises a sheet-like main body 31. The main body 31 includes an opening part 32 which has at least one penetration groove 33 penetrating in a thickness direction Z. A folded region 35 which can be folded and deformed along a line segment 33L is provided at a portion surrounded by the line segment 33L connecting a first end 33P1 and a second end 33P2 of the penetration groove 33 in the shortest distance and the penetration groove 33 extending from the first end 33P1 to the second end 33P2. The folded region 35 is located in plane with the main body 31 other than the folded region 35.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a wick for a heat diffusion device, a heat diffusion device, and an electronic device.

Background Art

[0002] In recent years, the heat generation amount has increased due to the high integration and high performance of elements. In addition, as products are miniaturized, the heat generation density increases, so heat dissipation measures are important. This situation is particularly remarkable in the field of mobile terminals such as smartphones and tablets. As a heat countermeasure member, a graphite sheet or the like is often used, but since its heat transport amount is not sufficient, the use of various heat countermeasure members is being studied. Among them, as a heat diffusion device that can very effectively diffuse heat, the use of a vapor chamber, which is a planar heat pipe, is being studied.

[0003] The vapor chamber has a structure in which a working medium 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 in an evaporation section that absorbs heat from the heat generating element such as an electronic component, evaporates inside the vapor chamber, then moves inside the vapor chamber, is cooled, and returns to the liquid phase. The working medium that has returned to the liquid phase moves again to the evaporation section on the heat generating element side by the capillary force of the wick, and cools the heat generating element. By repeating this, the vapor chamber can operate independently without external power, and can diffusely transfer heat two-dimensionally at high speed by utilizing the latent heat of vaporization and the latent heat of condensation of the working medium.

[0004] Patent Document 1 discloses a heat diffusion device including a housing having a first inner wall surface and a second inner wall surface facing each other in the thickness direction, a working medium enclosed in the internal space of the housing, and a wick structure disposed in the internal space of the housing. The wick structure includes a support portion in contact with the first inner wall surface, and a perforated portion made of the same material as the support portion and integrally formed with the support portion.

Prior Art Documents

[0005] [Patent document 1] International Publication No. 2023 / 090265 [Summary of the invention] [The problem that the invention is trying to solve [Problem to be Solved]

[0006] In a heat diffusion device such as that described in Patent Document 1, if the pore size of the wick is reduced in order to prioritize the transport performance of the liquid-phase working medium (hereinafter also referred to as the working fluid), the passing diffusibility of the gas-phase working medium (hereinafter also referred to as the vapor) decreases, and there is a risk that heat from the heat source will be retained. On the other hand, if the pore size of the wick is increased in order to prioritize the passing diffusibility of the vapor, there is a risk that the supply performance of the working fluid to the heat source will decrease, and there is a risk that the supply of the heat transport medium to the heat source will be insufficient, and the heat from the heat source will be retained.

[0007] Thus, in a wick used in a heat diffusion device such as a vapor chamber, a small pore size is required from the viewpoint of the transport performance of the working liquid, while a large pore size is required from the viewpoint of the vapor passing and diffusibility, and the two are in a trade-off relationship, which is a constraint on the wick function.

[0008] The present invention has been made to solve the above problems, and aims to provide a wick for a heat diffusion device that can achieve both the transport performance of the working liquid and the vapor passing and diffusibility. Furthermore, the present invention aims to provide a heat diffusion device including the wick for a heat diffusion device, and an electronic device including the heat diffusion device.

Means for solving the problem

[0009] The wick for a heat diffusion device of the present invention includes a sheet-shaped main body. The main body includes an opening having at least one through groove penetrating in the thickness direction. A bent region capable of being bent along the line segment is provided in a portion surrounded by a line segment connecting the first end and the second end of the through groove shortest and the through groove connecting from the first end to the second end. The bent region is located on the same plane as the main body other than the bent region.

[0010] The heat diffusion device of the present invention 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 wick disposed in the internal space of the housing. The wick is the wick for a heat diffusion device of the present invention.

[0011] The electronic device of the present invention includes the heat diffusion device of the present invention.

Advantages of the Invention

[0012] According to the present invention, it is possible to provide a wick for a heat diffusion device capable of achieving both the transport performance of the working liquid and the passage diffusibility of the vapor. Furthermore, according to the present invention, it is possible to provide a heat diffusion device including the wick for a heat diffusion device, and an electronic device including the heat diffusion device.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, the wick for the heat diffusion device of the present invention will be described. However, the present invention is not limited to the following embodiments, and can be appropriately modified and applied without changing the gist of the present invention. In addition, a combination of two or more of the individual preferred configurations of the present invention described below is also the present invention.

[0015] The wick for a heat diffusion device of the present invention can be disposed in the internal space of a housing that constitutes the heat diffusion device. Therefore, a heat diffusion device including the wick for a heat diffusion device of the present invention is also one of the present inventions. As described above, the heat diffusion device of the present invention operates independently without requiring external power, and can two-dimensionally and rapidly diffuse heat by utilizing the latent heat of vaporization and the latent heat of condensation of a working medium.

[0016] Hereinafter, as an embodiment of the heat diffusion device of the present invention, a vapor chamber will be described as an example. The heat diffusion device of the present invention is also applicable to heat diffusion devices such as heat pipes.

[0017] The drawings shown below are schematic diagrams, and their dimensions, scales of aspect ratios, etc. may differ from those of actual products. In the figures, the same or corresponding parts shall be denoted by the same reference numerals. Also, in each figure, the same elements are denoted by the same reference numerals and redundant descriptions are omitted.

[0018] In this specification, terms indicating the relationship between elements (e.g., "vertical", "parallel", "orthogonal", etc.) and terms indicating the shape of elements are not expressions representing only strict meanings, but are expressions meaning that they include substantially equivalent ranges, for example, differences of about several percent. Also, in this specification, "equivalent" or "constant" is not an expression meaning only when they are completely equivalent or constant, but is an expression meaning that they are substantially equivalent or constant, for example, including differences of about several percent.

[0019] FIG. 1 is a perspective view schematically showing an example of a heat diffusion device including the wick for a heat diffusion device of the present invention. FIG. 2 is an example of a cross-sectional view taken along line II-II of the heat diffusion device shown in FIG. 1. FIG. 3 is an example of an exploded perspective view of the heat diffusion device shown in FIG. 1.

[0020] The vapor chamber (heat dissipation device) 1 shown in FIGS. 1, 2, and 3 includes a hollow housing 10 that is hermetically sealed. 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. An internal space is provided in the housing 10. The vapor chamber 1 further includes a working medium 20 enclosed in the internal space of the housing 10 and a wick 30 disposed in the internal space of the housing 10. The wick 30 is a wick for the heat dissipation device of the present invention.

[0021] As shown in FIG. 2, the vapor chamber 1 may further include a support column 40 disposed in the internal space of the housing 10 (the illustration of the support column 40 is omitted in FIG. 3). Further, the vapor chamber 1 may further include a protrusion 50 disposed in the internal space of the housing 10 (the illustration of the protrusion 50 is omitted in FIG. 3). Note that the vapor chamber 1 may include both the support column 40 and the protrusion 50, may include only one of the support column 40 and the protrusion 50, or may not include the support column 40 and the protrusion 50.

[0022] As shown in FIG. 1, an evaporation portion (EP) for evaporating the enclosed working medium 20 (see FIG. 2) is set in the housing 10. As shown in FIG. 3, a heat source (HS), which is a heating element, is disposed on the outer surface of the housing 10. Examples of the heat source HS include electronic components of an electronic device, such as a central processing unit (CPU). Among the internal space of the housing 10, the portion near the heat source HS and heated by the heat source HS corresponds to the evaporation portion EP.

[0023] 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 means 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, of the thickness.

[0024] The size of the vapor chamber 1, that is, the size of the housing 10, is not particularly limited. The width and length of the vapor chamber 1 can be appropriately set according to the application. The width and length of the vapor chamber 1 are each, 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. The width and length of the vapor chamber 1 may be the same or different.

[0025] The housing 10 is preferably composed of a first sheet 11 and a second sheet 12 that are joined at their outer edges.

[0026] When the housing 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 characteristics suitable for use as a heat diffusion device such as a vapor chamber, 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.

[0027] 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 method of such joining is not particularly limited, but for example, laser welding, resistance welding, diffusion bonding, brazing, TIG welding (tungsten-inert gas welding), ultrasonic bonding, or resin encapsulation can be used, and preferably laser welding, resistance welding, or brazing can be used.

[0028] The thicknesses of the first sheet 11 and the second sheet 12 are not particularly limited, but are each preferably 10 μm or more and 200 μm or less, more preferably 30 μm or more and 100 μm or less, and still more 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. Also, the thickness of each of the first sheet 11 and the second sheet 12 may be the same throughout, or a part thereof may be thinner.

[0029] 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.

[0030] The overall thickness of the 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.

[0031] The planar shape of the housing 10 as viewed from the thickness direction Z is not particularly limited, and examples include polygons such as triangles or rectangles, circles, ellipses, and shapes combining these. Also, the planar shape of the housing 10 may be L-shaped, C-shaped (U-shaped), stepped, or the like. Further, the housing 10 may have a through-hole. The planar shape of the housing 10 may be a shape according to the use of a heat diffusion device such as a vapor chamber, the shape of the incorporation location of the heat diffusion device, and the shapes of other components present in the vicinity.

[0032] The working medium 20 is not particularly limited as long as it can cause a gas-liquid phase change in the environment within the housing 10, and for example, water, alcohols, alternative refrigerants, etc. can be used. For example, the working medium 20 is an aqueous compound, preferably water.

[0033] The wick 30 has a capillary structure capable of moving the working medium 20 by capillary force.

[0034] The material constituting the wick 30 is not particularly limited, but is preferably a metal, such as copper, nickel, aluminum, magnesium, titanium, iron, or an alloy mainly composed of these, and particularly preferably copper or a copper alloy. The material constituting the wick 30 may be the same as or different from the material constituting the housing 10.

[0035] The size and shape of the wick 30 are preferably sheet-like. For example, it is preferable that the wick 30 is continuously arranged in the internal space of the housing 10. When viewed from the thickness direction Z, the wick 30 may be arranged throughout the internal space of the housing 10, or may be arranged in a part of the internal space of the housing 10.

[0036] The thickness of the wick 30 is not particularly limited, but is, for example, 2 μm or more and 200 μm or less, preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 40 μm or less. The thickness of the wick 30 may be partially different.

[0037] As shown in FIG. 2, a support column 40 in contact with the second inner surface 12a may be arranged in the internal space of the housing 10. In the example shown in FIG. 2, the support column 40 is arranged between the second inner surface 12a of the housing 10 and the wick 30. It is possible to support the housing 10 and the wick 30 by the support column 40.

[0038] The material constituting the support column 40 is not particularly limited, and examples thereof include resins, metals, ceramics, or mixtures or laminates thereof. Further, as shown in FIG. 2, the support column 40 may be integral with the housing 10, and may be formed, for example, by performing processing such as etching on the second inner surface 12a of the housing 10.

[0039] The shape of the support column 40 is not particularly limited as long as it can support the housing 10 and the wick 30. Examples of the shape of the cross section perpendicular to the height direction of the support column 40 include polygons such as rectangles, circles, and ellipses.

[0040] As shown in FIG. 2, the support column 40 may have a tapered shape that narrows in width from the second inner surface 12a of the housing 10 toward the wick 30. Thereby, the flow path between the support columns 40 can be widened on the wick 30 side. The width of the support column 40 may be constant, or may widen, from the second inner surface 12a of the housing 10 toward the wick 30.

[0041] The height of the support columns 40 may be the same or different in one vapor chamber.

[0042] The arrangement of the support columns 40 is not particularly limited, but is preferably evenly arranged in a predetermined area, and more preferably evenly arranged throughout. By arranging the support columns 40 evenly, uniform strength can be ensured throughout the heat diffusion device such as a vapor chamber. For example, it is preferable that the center-to-center distance (pitch) of the support columns 40 is constant.

[0043] As shown in FIG. 2, a protrusion 50 in contact with the first inner surface 11a may be arranged in the internal space of the housing 10. In the example shown in FIG. 2, the protrusion 50 is arranged between the first inner surface 11a of the housing 10 and the wick 30.

[0044] The liquid-phase working medium 20 is held between the protrusions 50. Thereby, the heat transport capacity of a heat diffusion device such as a vapor chamber can be improved.

[0045] In this specification, the "protrusion" refers to a portion that is relatively higher in height than its surroundings, and includes not only a portion protruding from the inner surface of the housing, but also a portion that is relatively higher in height due to a recess formed in the inner surface of the housing, such as a groove.

[0046] As shown in FIG. 2, the protrusion 50 may be integral with the housing 10, and may be formed, for example, by performing a process such as etching on the first inner surface 11a of the housing 10.

[0047] The shape of the protrusion 50 is not particularly limited. Examples of the shape of a cross-section perpendicular to the height direction of the protrusion 50 include polygons such as rectangles, circles, ellipses, and the like.

[0048] As shown in FIG. 2, the protrusion 50 may have a tapered shape that narrows in width from the first inner surface 11a of the housing 10 toward the wick 30. Thereby, the flow path between the protrusions 50 can be widened on the wick 30 side. The width of the protrusion 50 may be constant, or may widen, from the first inner surface 11a of the housing 10 toward the wick 30.

[0049] The heights of the protrusions 50 may be the same or different in one vapor chamber.

[0050] The arrangement of the protrusions 50 is not particularly limited, but is preferably evenly arranged in a predetermined region, and more preferably evenly arranged throughout. For example, it is preferable that the protrusions 50 are arranged such that the center-to-center distance (pitch) is constant.

[0051] The height of the protrusion 50 is preferably smaller than the height of the support column 40.

[0052] The center-to-center distance between adjacent protrusions 50 is preferably smaller than the center-to-center distance between adjacent support columns 40.

[0053] The equivalent circle diameter of a cross-section perpendicular to the height direction of the end portion of the protrusion 50 on the wick 30 side is preferably smaller than the equivalent circle diameter of a cross-section perpendicular to the height direction of the end portion of the support column 40 on the wick 30 side.

[0054] As described above, the wick 30 is a wick for a heat diffusion device of the present invention.

[0055] FIG. 4 is a plan view schematically showing an example of the wick for a heat diffusion device of the present invention. Note that FIG. 4 is a plan view of the portion indicated by IV in FIG. 3.

[0056] The wick (wick for heat dissipation device) 30 shown in Fig. 4 includes a sheet-like main body 31.

[0057] The main body 31 includes an opening 32. The main body 31 may include at least one opening 32, but preferably includes a plurality of openings 32.

[0058] The arrangement of the openings 32 is not particularly limited, but preferably evenly in a predetermined region of the main body 31, more preferably evenly throughout the main body 31. For example, the openings 32 are arranged such that the center-to-center distance (pitch) between adjacent openings 32 is constant.

[0059] When the main body 31 includes a plurality of openings 32, the shapes, sizes, etc. of the openings 32 may be the same or different.

[0060] The opening 32 has a through groove 33 that penetrates in the thickness direction Z. The opening 32 may have at least one through groove 33. The shape of the through groove 33 is not particularly limited and may be linear or curved. The extending direction, width, length, etc. of the through groove 33 are also not particularly limited.

[0061] In the example shown in Fig. 4, each opening 32 has eight through grooves 33 that communicate with each other at the center. In each opening 32, the through grooves 33 are arranged radially. Further, each opening 32 has a through hole 34 communicating with the through groove 33 at the radial center.

[0062] As shown in Fig. 4, a bent region 35 capable of bending deformation along the line segment 33L is provided in the portion surrounded by the line segment 33L that connects the first end 33P1 and the second end 33P2 of the through groove 33 and the through groove 33 that connects from the first end 33P1 to the second end 33P2. In the example shown in Fig. 4, eight bent regions 35 are provided in each opening 32.

[0063] The bending region 35 is located on the same plane as the main body 31 other than the bending region 35. Specifically, if the bending region 35 is within three times the thickness of the main body 31, it is defined that "the bending region 35 is located on the same plane as the main body 31 other than the bending region 35". That is, even if the bending region 35 protrudes from the main body 31, as long as the vertical protrusion of the main body 31 is within ±1 times the thickness of the main body 31, it is acceptable.

[0064] FIG. 5A, FIG. 5B, and FIG. 5C are cross-sectional views schematically showing an example of the operating state of the wick for a heat diffusion device shown in FIG. 4. FIG. 6A, FIG. 6B, and FIG. 6C are perspective views schematically showing an example of the operating state of the wick for a heat diffusion device shown in FIG. 4.

[0065] As shown in FIGS. 5A and 6A, when the working medium 20 evaporates due to the heat from the heat source HS and the vapor pressure increases, pressure is applied to the opening 32 of the wick 30.

[0066] As described above, the bending region 35 is provided in the opening 32 of the wick 30. Therefore, as shown in FIGS. 5B and 6B, the bending region 35 expands due to the vapor pressure, and the diameter D of the opening 32 increases. Thereby, the diffusion of the vapor can be promoted.

[0067] On the other hand, when the vapor pressure decreases, the bending region 35 returns to its original position due to the spring property of the wick 30, and the diameter D of the opening 32 decreases. Thereby, the capillary pressure of the wick 30 is restored, and the supply of the working fluid resumes.

[0068] As described above, in the wick for a heat diffusion device of the present invention, since the bending region is provided in the opening, the diameter of the opening changes reversibly due to the vapor pressure when the vapor passes through and diffuses through the opening. Therefore, the diameter of the opening can be increased only when necessary to release the vapor pressure. As a result, it becomes possible to achieve both the transport performance of the working fluid and the passage and diffusibility of the vapor.

[0069] In the wick for a heat diffusion device of the present invention, it is preferable that the bending region is arranged so as to overlap at least a part of the evaporation section in the thickness direction. In other words, it is preferable that the heat source is arranged so that at least a part of the bending region overlaps in the thickness direction. Specifically, it is preferable that the electronic component is arranged so that at least a part of the bending region overlaps in the thickness direction.

[0070] In the wick for a heat diffusion device of the present invention, from the viewpoint of ensuring springiness, it is preferable that the main body has a Young's modulus of 110 GPa or more and 200 GPa or less. For example, the material constituting the main body is preferably a copper alloy, and more preferably phosphor bronze.

[0071] Note that the Young's modulus of the main body can be measured, for example, by a resonant natural vibration method.

[0072] In the wick for a heat diffusion device of the present invention, the opening may have at least one through groove as long as the bending region is provided.

[0073] In the wick for a heat diffusion device of the present invention, the opening may have at least one through hole communicating with the through groove. The shape of the through hole is not particularly limited, but it is preferable that the shape of the cross section perpendicular to the thickness direction is circular or elliptical. The diameter of the through hole is preferably larger than the width of the through groove.

[0074] In the wick for a heat diffusion device of the present invention, the opening may have one non-linear through groove.

[0075] FIGS. 7A, 7B and 7C are plan views schematically showing an example of an opening having one non-linear through groove.

[0076] As shown in FIGS. 7A and 7B, the opening 32 may have one curved through groove 33, and as shown in FIG. 7C, it may have one bent through groove 33.

[0077] In the wick for a heat dissipation device of the present invention, the opening may have two or more through grooves communicating with each other. By increasing the number of through grooves, the ease of elastic deformation in the bending region can be adjusted, and the opening degree of the diameter of the opening can be controlled. The widths, lengths, shapes, etc. of the through grooves may be the same or different.

[0078] When the opening has two or more through grooves communicating with each other, it is preferable that the through grooves are arranged radially at the opening.

[0079] FIGS. 8A, 8B, 8C, 8D, 8E and 8F are plan views schematically showing examples of openings having radially arranged through grooves.

[0080] The opening 32 may have a linear through groove 33 as shown in FIGS. 8A, 8B and 8C, or may have a curved through groove 33 as shown in FIGS. 8D, 8E and 8F. The linear through groove 33 may not be bent as shown in FIGS. 8A and 8B, or may be bent as shown in FIG. 8C. In the opening 32, through grooves 33 having different widths, lengths, shapes, etc. may be combined.

[0081] When the through grooves are arranged radially, the opening may have a through hole communicating with the through grooves at the radiation center. The diameter of the through hole is preferably larger than the width of the through groove.

[0082] FIGS. 9A, 9B and 9C are plan views schematically showing examples of openings having through holes at the radiation center.

[0083] FIG. 9A is an example in which a through hole 34 is provided at the radiation center of the opening 32 shown in FIG. 8A, and FIGS. 9B and 9C are examples in which a through hole 34 is provided at the radiation center of the opening 32 shown in FIG. 8B. The size, shape, etc. of the through hole 34 are not particularly limited.

[0084] In the wick for a heat diffusion device of the present invention, the opening may have a through-hole communicating with the through-groove at at least one of the first end and the second end. By narrowing the width between the first end and the second end, elastic deformation becomes easier. The diameter of the through-hole is preferably larger than the width of the through-groove.

[0085] Figures 10A and 10B are plan views schematically showing an example of an opening having a through-hole at the end of the through-groove.

[0086] Figure 10A shows an example in which a through-hole 34 is provided at the end of the through-groove 33 of the opening 32 shown in Figure 7B, and Figure 10B shows an example in which a through-hole 34 is provided at the end of the through-groove 33 of the opening 32 shown in Figure 9B. The size, number, shape, etc. of the through-hole 34 are not particularly limited. The size, shape, etc. of the through-holes 34 provided at each end of the through-groove 33 may be the same or different.

[0087] In the wick for a heat diffusion device of the present invention, when the opening has two or more through-grooves communicating with each other, through-holes provided at the ends and through-grooves without through-holes provided at the ends may be mixed.

[0088] In the wick for a heat diffusion device of the present invention, the method of forming the opening is not particularly limited. For example, the opening can be formed by performing processing such as etching, shearing with a mold, press working with a mold (punching) on the metal foil constituting the wick.

[0089] In the wick for a heat diffusion device of the present invention, a convex portion protruding in one direction in the thickness direction of the main body may be provided at the periphery of the opening. Specifically, a convex portion protruding in one direction in the thickness direction of the main body may be provided at the periphery of at least one through-groove. Further, when the opening has a through-hole, a convex portion protruding in one direction in the thickness direction of the main body may be provided at the periphery of at least one through-hole.

[0090] In the wick for a heat diffusion device of the present invention, openings having different shapes and sizes may be mixed.

[0091] In the wick for a heat diffusion device of the present invention, an opening without a bent region may be included. Examples of the opening without a bent region include an opening having only a through hole, an opening having only one linear through groove, and the like.

[0092] The heat diffusion 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 regarding the configuration, manufacturing conditions, etc. of the heat diffusion device.

[0093] In the example shown in FIG. 2, the housing 10 is integrally formed with the protruding portion 50. However, for example, the wick 30 may be integrally formed with the protruding portion 50.

[0094] FIG. 11 is a cross-sectional view schematically showing an example of a wick integrally formed with a protruding portion. FIG. 12 is a cross-sectional view schematically showing another example of a wick integrally formed with a protruding portion.

[0095] In the wick 30A shown in FIG. 11 and the wick 30B shown in FIG. 12, the main body 31 is integrally formed with the protruding portion 50.

[0096] The term "integrally formed" as used herein means that there is no interface between the main body 31 and the protruding portion 50, and specifically means that no boundary can be discerned between the main body 31 and the protruding portion 50. For example, in the case where a copper pillar as the protruding portion 50 and a copper foil as the main body 31 are fixed by diffusion bonding or spot bonding, etc., it is difficult to bond the entire surface between the main body 31 and the protruding portion 50, so a gap is generated in a part between the main body 31 and the protruding portion 50. In such a case, since a boundary can be discerned between the main body 31 and the protruding portion 50, it can be said that the main body 31 and the protruding portion 50 are not integrally formed.

[0097] In the wick 30A shown in FIG. 11, for example, by removing a part of the metal foil by etching or the like, the protruding portion 50 can be formed on the remaining portion.

[0098] In the wick 30B shown in FIG. 12, for example, by bending and denting a part of the metal foil by pressing or the like, the protruding portion 50 can be formed in the dented portion.

[0099] In the heat diffusion device of the present invention, the housing may have one evaporation part or a plurality of evaporation parts. That is, one heat source may be arranged on the outer surface of the housing, or a plurality of heat sources may be arranged.

[0100] In the heat diffusion device of the present invention, when the housing is composed of the first sheet and the second sheet, the first sheet and the second sheet may overlap so that their ends coincide, or may overlap with their ends shifted.

[0101] In the heat diffusion device of the present invention, when the housing is composed of the first sheet and the second sheet, the material constituting the first sheet and the material constituting the second sheet may be different. For example, by using a material with high strength for the first sheet, the stress applied to the housing can be dispersed. Also, by making the materials of both different, one function can be obtained with one sheet and another function can be obtained with the other sheet. The above functions are not particularly limited, but examples include a heat conduction function, an electromagnetic wave shielding function, and the like.

[0102] The heat diffusion device of the present invention 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 invention is also one of the present inventions. Examples of the electronic device of the present invention include smartphones, tablet terminals, notebook computers, game devices, wearable devices, and the like. As described above, the heat diffusion device of the present invention operates independently without requiring external power, and can diffusely transfer heat two-dimensionally at high speed by utilizing 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 invention can effectively achieve heat dissipation in the limited space inside the electronic device.

[0103] In the electronic device of the present invention, it is preferable that the electronic components are arranged such that at least a part of the bent region of the wick for the heat diffusion device overlaps in the thickness direction.

[0104] The following content is disclosed in this specification.

[0105] <1> Comprising a sheet-like main body, The main body includes an opening having at least one through groove penetrating in the thickness direction, A bent region capable of bending deformation along the line segment is provided in a portion surrounded by a line segment connecting the first end and the second end of the through groove shortest and the through groove connecting from the first end to the second end, The bent region is located on the same plane as the main body other than the bent region, A wick for a heat diffusion device.

[0106] <2> The opening has two or more of the through grooves communicating with each other, The wick for a heat diffusion device according to <1>.

[0107] <3> In the opening, the through grooves are arranged radially, The wick for a heat diffusion device according to <2>.

[0108] <4> The above opening has a through-hole communicating with the above through-groove at the radiation center. The wick for a heat diffusion device according to <3>.

[0109] <5> The above opening has one non-linear above through-groove. The wick for a heat diffusion device according to <1>.

[0110] <6> The above opening has a through-hole communicating with the above through-groove at at least one of the above first end and the above second end. The wick for a heat diffusion device according to any one of <1> to <5>.

[0111] <7> The above opening has at least one through-hole communicating with the above through-groove. The wick for a heat diffusion device according to any one of <1> to <6>.

[0112] <8> The above body has a Young's modulus of 110 GPa or more and 200 GPa or less. The wick for a heat diffusion device according to any one of <1> to <7>.

[0113] <9> 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 above housing, A wick disposed in the internal space of the above housing, and comprising: The above wick is the wick for a heat diffusion device according to any one of <1> to <8>. Heat diffusion device.

[0114] <10> The above housing has an evaporation section for evaporating the above working medium. The bending region of the wick for the heat diffusion device is arranged so as to overlap at least a part of the evaporation section in the thickness direction. The heat diffusion device according to <9>.

[0115] <11> An electronic device including the heat diffusion device according to <9> or <10>.

[0116] <12> The electronic device further includes an electronic component arranged so that at least a part of the bending region of the wick for the heat diffusion device overlaps in the thickness direction. The electronic device according to <11>.

Industrial Applicability

[0117] The heat diffusion device of the present invention can be used for a wide range of applications in fields such as portable information terminals. For example, it can be used to lower the temperature of a heat source such as a CPU and extend the usage time of an electronic device, and can be used in smartphones, tablet terminals, notebook personal computers, and the like.

Explanation of Signs

[0118] 1 Vapor chamber (heat diffusion device) 10 Housing 11 First sheet 11a First inner surface 12 Second sheet 12a Second inner surface 20 Working medium 30, 30A, 30B Wick (wick for heat diffusion device) 31 Body 32 Opening 33 Through groove 33L Line segment connecting the first end and the second end of the through groove at the shortest distance 33P1 First end 33P2 Second end 34 Through hole 35 Bending region 40 Support column 50 Protrusion D Diameter of the opening EP evaporation section HS heat source X width direction Y length direction Z thickness direction

Claims

1. It has a sheet-like body, The body includes an opening having at least one through groove extending through the body in a thickness direction; A bending region capable of bending deformation at the line segment is provided in a portion surrounded by the line segment connecting the first end and the second end of the through groove at the shortest distance and the through groove connecting the first end to the second end, the bend region is flush with the body other than the bend region; Wick for heat spreading devices.

2. The opening has two or more of the through grooves communicating with each other. The wick for a heat spreading device according to claim 1.

3. In the opening, the through grooves are radially arranged. The wick for a heat spreading device according to claim 2.

4. The opening has a through hole at a radial center thereof, the through hole communicating with the through groove. The wick for a heat spreading device according to claim 3.

5. The opening has one non-linear through groove. The wick for a heat spreading device according to claim 1.

6. The opening has a through hole communicating with the through groove at at least one of the first end and the second end. The wick for a heat spreading device according to any one of claims 1 to 5.

7. The opening has at least one through hole communicating with the through groove. The wick for a heat spreading device according to any one of claims 1 to 5.

8. The body has a Young's modulus of 110 GPa or more and 200 GPa or less. The wick for a heat spreading device according to any one of claims 1 to 5.

9. 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 interior space of the housing, The wick is a wick for a heat spreading device according to any one of claims 1 to 5. Heat spreading device.

10. The housing has an evaporation portion that evaporates the working medium, The bent region of the wick for the heat diffusion device is arranged to overlap at least a part of the evaporation portion in a thickness direction.

10. The heat spreading device of claim 9.

11. An electronic device comprising the heat spreading device according to claim 9.

12. The wick further includes an electronic component arranged so that at least a portion of the electronic component overlaps with the folded region of the wick in the thickness direction. The electronic device according to claim 11.

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