Vapor chamber, sheet for vapor chamber, and electronic device

Abstract

To provide a vapor chamber that can increase heat transport capacity.SOLUTION: A vapor chamber includes a sealed space in which a working fluid is encapsulated. The sealed space includes: a first flow passage and a liquid flow passage part adjacent to the first flow passage.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a vapor chamber that performs heat transport by refluxing a working fluid enclosed in a sealed space while undergoing a phase change.

Background Art

[0002] The amount of heat generated from electronic components such as a CPU (Central Processing Unit) provided in a personal computer and portable terminals such as a mobile phone and a tablet terminal tends to increase due to the improvement of information processing capabilities, and cooling technology is important. A heat pipe is well known as such a cooling means. This diffuses the heat at the heat source by transporting the heat at the heat source to other parts by a working fluid enclosed in the pipe, and cools the heat source.

[0003] On the other hand, in recent years, particularly in portable terminals such as mobile phones, thinning has been remarkable, and a cooling means thinner than a conventional heat pipe has been required. In response, for example, a vapor chamber as described in Patent Document 1 has been proposed.

[0004] A vapor chamber is a device that develops the concept of heat transport by a heat pipe in a plate-like member. That is, in the vapor chamber, a working fluid is enclosed between opposing flat plates, and this working fluid performs heat transport while undergoing a phase change, transports and diffuses the heat at the heat source, and cools the heat source.

[0005] More specifically, a vapor flow path and a condensate flow path are provided inside the vapor chamber, and a working fluid is enclosed therein. When the vapor chamber is arranged at the heat source, the working fluid receives heat from the heat source and evaporates near the heat source, becomes a gas (vapor), and moves through the vapor flow path. As a result, the heat from the heat source is smoothly transported to a position away from the heat source, and the heat source is cooled as a result. The gaseous working fluid that transports heat from the heat source moves to a position away from the heat source, is cooled and condensed by absorbing heat from the surroundings, and undergoes a phase change to the liquid state. The working fluid in the phase-changed liquid state passes through the condensate flow path, returns to the position of the heat source, and again receives heat from the heat source to evaporate and change to the gaseous state. Through the above cycle, the heat generated from the heat source is transported and diffused to a position away from the heat source, and the heat source is cooled.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present disclosure provides a vapor chamber capable of enhancing heat transport capacity.

Means for Solving the Problems

[0008] One aspect of the present disclosure is a vapor chamber in which a working fluid is enclosed in a sealed space, which is composed of three sheets stacked on top of each other. Among the three sheets, the sheet disposed in the center includes a first flow path that penetrates the sheet in the thickness direction and extends along the sheet surface, and a liquid flow path portion adjacent to the first flow path and having a second flow path. The second flow path is provided as a groove on each of one surface and the other surface in the thickness direction of the liquid flow path portion. The first flow path and the second flow path communicate with each other through communication openings provided on each of one surface and the other surface in the thickness direction of the liquid flow path portion.

Effects of the Invention

[0009] According to the present disclosure, the heat transport capacity of the vapor chamber can be enhanced.

Brief Description of the Drawings

[0010]

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Embodiments for Carrying Out the Invention

[0011] The following describes the present disclosure based on the forms shown in the drawings. In the following drawings, for ease of understanding, the sizes and ratios of members may be changed or exaggerated. Also, for ease of viewing, illustrations of parts that are not necessary for explanation and repeated reference numerals may be omitted. In addition, terms used in this specification, such as "parallel", "orthogonal", "identical", etc., which specify shapes, geometric conditions, physical properties, and their degrees, as well as lengths, angles, and values of physical properties, shall be interpreted to include ranges to the extent that similar functions can be expected, without being restricted to strict meanings. Further, in the drawings, for clarity, the shapes of a plurality of parts that can be expected to have similar functions are regularly described, but without being restricted to strict meanings, within the range where such functions can be expected, the shapes of such parts may be different from each other. Also, in the drawings, the boundary lines indicating the joining surfaces between members, etc., are shown as simple straight lines for convenience, but are not restricted to being strict straight lines, and within the range where the desired joining performance can be expected, the shape of such boundary lines is arbitrary.

[0012] 1. Embodiment 1 1.1. Embodiment 1a [Components] FIG. 1 shows an external perspective view of the vapor chamber 1 according to Embodiment 1a, and FIG. 2 shows an exploded perspective view of the vapor chamber 1. In these figures and each of the figures shown below, for convenience as needed, arrows (x, y, z) representing directions corresponding to a three-dimensional orthogonal coordinate system are also shown. Here, the in-plane direction in the xy plane is the plate surface direction of the vapor chamber 1 which is plate-shaped, and the z direction is the thickness direction.

[0013] As can be seen from FIGS. 1 and 2, the vapor chamber 1 of this embodiment has a first sheet 10, a second sheet 20, and a third sheet 30 (which may also be referred to as the "intermediate sheet 30"). Then, as will be described later, these sheets are overlapped and joined (diffusion bonding, soldering, etc.), so that a vapor chamber sheet is formed with a hollow portion based on the shape of the third sheet 30 formed between the first sheet 10 and the second sheet 20. And, by enclosing a working fluid in this hollow portion, a sealed space 2 (see, for example, FIG. 15) is formed, which becomes the vapor chamber 1.

[0014] <First sheet> In this embodiment, the first sheet 10 is a sheet-like member as a whole with its front and back surfaces (one and the other surfaces in the thickness direction, the inner surface 10a and the outer surface 10b) being flat. The first sheet 10 is composed of flat surfaces on both the front and back, and includes a flat inner surface 10a, a flat outer surface 10b on the opposite side of the inner surface 10a, and an end surface 10c that forms a thickness across the inner surface 10a and the outer surface 10b.

[0015] Also, the first sheet 10 includes a main body 11 and an injection portion 12. The main body 11 is a sheet-like portion that forms a hollow portion and a sealed space, and in this embodiment, it is a rectangle with rounded corners (so-called having an R) in plan view. However, the main body 11 of the first sheet 10 can be not only quadrilateral as in this embodiment, but also in a shape required for each vapor chamber. For example, it may be circular, elliptical, triangular, other polygons, and shapes having bent portions such as L-shaped, T-shaped, crank-shaped, U-shaped, etc. Also, it can be in a shape combining at least two of these.

[0016] The injection portion 12 is a portion for injecting a working fluid into the formed hollow portion, and in this embodiment, it is sheet-like in a quadrangle in plan view protruding from one side of the main body 11 that is rectangular in plan view.

[0017] The thickness of such a first sheet 10 is not particularly limited, but is preferably 1.0 mm or less, may be 0.75 mm or less, or may be 0.5 mm or less. On the other hand, this thickness is preferably 0.01 mm or more, may be 0.05 mm or more, or may be 0.1 mm or more. The range of this thickness may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Further, the range of this thickness may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values. This makes it possible to increase the number of scenarios where it can be applied as a thin vapor chamber.

[0018] Also, the material constituting the first sheet 10 is not particularly limited, but is preferably a metal with high thermal conductivity. Examples of this include copper and copper alloys. However, it does not necessarily have to be a metal material, and ceramics such as AlN, Si3N4, or Al2O3, or resins such as polyimide and epoxy are also possible. Also, a laminate of two or more types of materials within one sheet may be used, or the material may vary depending on the part.

[0019] The first sheet 10 may be a single layer or may be formed by laminating a plurality of sheets. For example, a sheet (clad material) in which a plurality of layers with different strengths are laminated may be used.

[0020] <Second sheet> In this embodiment, the second sheet 20 is also a sheet-like member with a flat front and back as a whole. The second sheet 20 is composed of flat surfaces on both the front and back, and includes a flat inner surface 20a, a flat outer surface 20b on the opposite side of the inner surface 20a, and an end surface 20c that forms the thickness across the inner surface 20a and the outer surface 20b. Also, the second sheet 20 also includes a main body 21 and an injection portion 22, similar to the first sheet 10. In addition, the second sheet 20 can be considered in the same way as the first sheet 10. However, the thickness and material of the second sheet 20 do not have to be the same as those of the first sheet 10, and they may be configured differently.

[0021] The second sheet 20 may also be a single layer, or a plurality of sheets may be laminated. For example, a sheet (clad material) in which a plurality of layers with different strengths are laminated may be used.

[0022] <Third sheet> In this embodiment, the third sheet 30 is a sheet sandwiched and overlapped between the inner surface 10a of the first sheet 10 and the inner surface 20a of the second sheet 20, and has a structure for the sealed space 2 in which the working fluid moves. FIGS. 3 and 4 show a plan view of the third sheet 30 (viewed from the z direction). FIG. 3 is a view of the surface overlapped with the first sheet 10, and FIG. 4 is a view of the surface overlapped with the second sheet 20. FIG. 5 shows a cross-sectional view taken along the line C1-C1 shown in FIG. 3, and FIG. 6 shows a cross-sectional view taken along the line C2-C2 shown in FIG. 3. Among the cross-sectional views, hatching (oblique lines) is applied to the part related to the cut surface, and for the part that needs to be displayed among the parts shown in the cross-sectional view that are not related to the cut surface, they are displayed without hatching. The same applies to the following drawings.

[0023] Note that the third sheet 30 may also be a single layer, or a plurality of sheets may be laminated. When a plurality of sheets are laminated, the following form may be formed after laminating the plurality of sheets, or the following form may be formed by individually processing the plurality of sheets and then overlapping them.

[0024] In this embodiment, the third sheet 30 includes a first surface 30a that overlaps the inner surface 10a of the first sheet 10, a second surface 30b that overlaps the inner surface 20a of the second sheet 20, and an end surface 30c that forms the thickness across the first surface 30a and the second surface 30b. Therefore, the first surface 30a appears in FIG. 3, and the second surface 30b appears in FIG. 4.

[0025] Further, the third sheet 30 includes a main body 31 and an injection part 32. The main body 31 is a sheet-like part that forms a hollow part in the sheet for the vapor chamber and a sealed space in the vapor chamber 1, and in this embodiment, it is a rectangle with rounded corners (so-called having an R) in plan view. However, the main body 31 can be not only quadrilateral as in this embodiment, but also in a shape required for the vapor chamber. For example, it may be circular, elliptical, triangular, other polygons, and also in a shape having a bent part such as L-shaped, T-shaped, crank-shaped, U-shaped, etc. Further, it can also be in a shape combining at least two of these.

[0026] The injection part 32 is a part for injecting the working fluid into the formed hollow part, and in this embodiment, it is a sheet-like shape that is quadrangular in plan view and protrudes from one side of the main body 31 that is rectangular in plan view. And in the injection part 32, a groove 32a communicating from the end face 30c to the main body 31 is provided on the second surface 30b side.

[0027] The thickness of the third sheet 30 can be set to be 0.03 mm or more and 0.8 mm or less. However, the thickness of the third sheet 30 is preferably thicker than the first sheet 10 and the second sheet 20. Thereby, the cross-section of the vapor flow path 4 described later can be made larger, and smoother movement of the working fluid becomes possible. The material of the third sheet 30 can be considered in the same way as the first sheet 10 and the second sheet 20.

[0028] A structure for the reflux of the working fluid is formed in the main body 31. Specifically, the main body 31 is configured to include an outer peripheral joint part 33, an outer peripheral liquid flow path part 34, an inner liquid flow path part 38, a vapor flow path groove 42, and a vapor flow path communication groove 44.

[0029] The vapor chamber 1 of this embodiment includes a vapor flow path 4 (see FIG. 15 etc.) which is a first flow path and through which the vapor of the working fluid passes, and a condensate flow path 3 (see FIG. 18 etc.) which is a second flow path and through which the condensate obtained by condensing and liquefying the working fluid passes. The vapor flow path groove 42 of the third sheet 30 forms the vapor flow path 4, and the liquid flow path grooves 35, 35 (see FIG. 7 etc.) provided in the outer peripheral liquid flow path portion 34 and the liquid flow path grooves 39, 40 (see FIGS. 13(a), 13(b) etc.) provided in the inner liquid flow path portion 38 form the condensate flow path 3.

[0030] <<Outer peripheral joint portion>> The outer peripheral joint portion 33 is a portion provided along the outer periphery of the main body 31, and includes an outer peripheral joint surface 33a provided on the first surface 30a of the main body 31 and an outer peripheral joint surface 33b provided on the second surface 30b. The outer peripheral joint surface 33a overlaps the outer peripheral portion of the inner surface 10a of the first sheet 10, and the outer peripheral joint surface 33b overlaps the outer peripheral portion of the inner surface 20a of the second sheet 20, and each is joined (diffusion bonding, brazing, etc.), whereby a hollow portion based on the shape of the third sheet 30 is formed between the first sheet 10 and the second sheet 20, and the working fluid is sealed therein to form a sealed space.

[0031] The width (the size in the direction orthogonal to the direction in which the outer peripheral joint portion 33 extends) of the outer peripheral joint portion 33 (the outer peripheral joint surface 33a and the outer peripheral joint surface 33b) indicated by W1 in FIGS. 3 to 7 can be appropriately set as needed. However, this width W1 is preferably 3.0 mm or less, may be 2.5 mm or less, and may be 2.0 mm or less. When the width W1 exceeds 3.0 mm, there is a risk that the internal volume of the sealed space will become small and sufficient vapor flow paths and condensate flow paths cannot be ensured. On the other hand, the width W1 is preferably 0.1 mm or more, may be 0.4 mm or more, and may be 0.8 mm or more. When the width W1 is less than 0.1 mm, there is a risk that the joint area will be insufficient when displacement occurs between the sheets during joining. The range of the width W1 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Further, the range of the width W1 may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values. Here, the widths of both the outer peripheral joint surface 33a and the outer peripheral joint surface 33b are indicated by W1, but the widths of the outer peripheral joint surface 33a and the outer peripheral joint surface 33b do not necessarily have to be the same and may be different widths.

[0032] <<Outer Peripheral Liquid Flow Path Portion>> The outer peripheral liquid flow path portion 34 functions as a liquid flow path portion and is a part of the condensate flow path 3, which is a second flow path through which the working fluid passes when it condenses and liquefies. FIGS. 7(a) and 7(b) show an enlarged view of the portion indicated by the arrow C3 in FIG. 5. Further, FIG. 8 shows an enlarged view (viewed from the z direction) of the outer peripheral liquid flow path portion 34 in plan view as viewed from the direction indicated by the arrow C4 in FIG. 7. That is, FIG. 8 shows a part of the outer peripheral liquid flow path portion 34 as viewed from the first surface 30a. Here, FIG. 7(a) is a cross-sectional view taken along the arrow C 15 -C 15 in FIG. 8, and FIG. 7(b) is a cross-sectional view taken along the arrow C 16 -C 16 in FIG. 8. FIG. 7(a) is a cross-section in which the convex portion 35a is arranged on the introduction portion 37 side, and FIG. 7(b) is a cross-section in which the communication opening 35b is arranged on the introduction portion 37 side.

[0033] As can be seen from these figures, the outer peripheral liquid flow path portion 34 is a portion that is formed along the inner side of the outer peripheral joint portion 33 in the main body 31 and is provided along the outer periphery of the portion that becomes the sealed space 2. Further, on each of the first surface 30a and the second surface 30b of the outer peripheral liquid flow path portion 34, a plurality of grooves extending along the outer peripheral direction of the main body 31, i.e., the liquid flow path grooves 35 (on the first surface 30a side) and the liquid flow path grooves 36 (on the second surface 30b side), are formed, and the plurality of liquid flow path grooves 35 and the liquid flow path grooves 36 are arranged at a predetermined interval in a direction different from the direction in which the liquid flow path grooves 35 and the liquid flow path grooves 36 extend. Therefore, as can be seen from FIGS. 5 to 7, in the outer peripheral liquid flow path portion 34, in its cross section, on the first surface 30a side, the concave liquid flow path grooves 35 and the convex portions 35a between the liquid flow path grooves 35 are repeatedly formed with concavities and convexities. Furthermore, on the second surface 30b side, the concave liquid flow path grooves 36 and the convex portions 36a between the liquid flow path grooves 36 are repeatedly formed with concavities and convexities. That is, in this embodiment, the liquid flow path grooves that become the condensate flow path 3 are provided on each of one side and the other side (front and back) in the thickness direction (z direction).

[0034] In this way, by providing the plurality of liquid flow path grooves 35 and the liquid flow path grooves 36 on each of the first surface 30a and the second surface 30b, the flow path cross-sectional area of the condensate flow path 3 as a whole is ensured to be an appropriate size, and the condensate with the required flow rate can be made to flow. At the same time, the depth and width of each of the liquid flow path grooves 35 and the liquid flow path grooves 36 are reduced, and thereby the flow path cross-sectional area of the condensate flow path 3, which is the second flow path (see FIGS. 17(a), 17(b), etc.), can be reduced to utilize a large capillary force. Note that the depth and width may be changed respectively between one side and the other side (front and back), i.e., between the liquid flow path grooves 35 and the liquid flow path grooves 36. According to this, the flow rate and the capillary force can be adjusted independently according to the final product.

[0035] Here, since the liquid flow path grooves 35 and the liquid flow path grooves 36 are grooves, in their cross-sectional shape, they have bottoms, and the opposite side facing the bottoms is open. As will be described later, when the first sheet 10 and the second sheet 20 are stacked on the third sheet 30, this opening is blocked to form the condensate flow path 3. In this embodiment, the cross-sections of the liquid flow path grooves 35 and 36 are semi-elliptical. However, the cross-sectional shape is not limited to a semi-elliptical shape, and may be a circular shape, a rectangular shape, a square shape, a trapezoidal shape or other polygonal shapes, or a combination of any of these shapes.

[0036] Furthermore, in this embodiment, in the outer peripheral liquid flow path portion 34, as can be seen from FIG. 8, adjacent liquid flow path grooves 35 communicate with each other through communication openings 35b at a predetermined interval. As a result, the equalization of the amount of condensate is promoted among the plurality of liquid flow path grooves 35, the condensate can flow efficiently, and a smooth reflux of the working fluid is possible. Note that since FIG. 8 shows the first surface 30a side, the liquid flow path groove 35, the convex portion 35a, and the communication opening 35b will be described. However, the liquid flow path groove 36 and the convex portion 36a provided on the second surface 30b side can be considered in the same manner, and a communication opening 36b (not shown) is provided, and it can be considered in the same manner as the liquid flow path groove 35, the convex portion 35a, and the communication opening 35b.

[0037] In this embodiment, as shown in FIG. 8, the communication openings 35b may be arranged at different positions in the direction in which the liquid flow path grooves 35 extend across the groove of one liquid flow path groove 35. That is, the convex portions 35a and the communication openings 35b are alternately arranged along the direction orthogonal to the direction in which the liquid flow path grooves extend. However, the present invention is not limited thereto. For example, as shown in FIG. 9, the communication openings 35b may be arranged so as to face the same position in the direction in which the liquid flow path grooves 35 extend across the groove of one liquid flow path groove 35.

[0038] In addition, for example, the embodiments shown in FIGS. 10 to 12 can also be adopted. FIGS. 10 to 12 show diagrams showing one liquid flow path groove 35, two convex portions 35a sandwiching the same, and one communication opening 35b provided in each convex portion 35a from the same perspective as FIG. 8. In all of these, the shape of the convex portion 35a is different from the example of FIG. 8 in the perspective (plan view). That is, in the convex portion 35a shown in FIG. 8, the width is the same as that of other portions and constant even at the end where the communication opening 35b is formed. On the other hand, in the convex portion 35a having the shape shown in FIGS. 10 to 12, the width at the end where the communication opening 35b is formed is formed to be smaller than the maximum width of the convex portion 35a. More specifically, FIG. 10 shows an example in which the corner becomes arc-shaped at the end and an R is formed at the corner, so that the width of the end becomes smaller. FIG. 11 shows an example in which the end is semi-circular, so that the width of the end becomes smaller. FIG. 12 shows an example in which the end tapers to a sharp point.

[0039] As shown in FIGS. 10 to 12, by forming the width at the end where the communication opening 35b is formed in the convex portion 35a to be smaller than the maximum width of the convex portion 35a, the working fluid can easily move through the communication opening 35b, and the movement of the working fluid to the adjacent condensate flow path becomes easy.

[0040] Further, in this embodiment, as shown in FIG. 5, an introduction portion 37 is provided in the outer peripheral liquid flow path portion 34. The introduction portion 37 is a portion formed at the interface with the vapor flow path groove 42 and is a portion protruding toward the vapor flow path groove 42 side. This embodiment includes a top portion 37a that protrudes most at the center in the thickness direction (z direction), and an introduction surface 37b that is concave in an arc shape toward the outer peripheral liquid flow path portion 34 side in a cross-sectional view is provided from the top portion 37a toward the first surface 30a and the second surface 30b side (z direction). The form of the introduction portion 37 is not limited to this. The position of the top portion 37a may be anywhere in the z direction. The introduction surface 37b may be a straight line or a non-circular arc curve in cross-section. Further, the top portion 37a may be a point or may have a length in cross-sectional view.

[0041] According to such an introduction portion 37, condensate easily accumulates on the introduction surface 37b due to the above-described shape, and the movement of the working fluid between the condensate flow path 3 and the vapor flow path 4 through the introduction portion 37 becomes smooth, and the heat transport capacity can be further enhanced.

[0042] The outer peripheral liquid flow path portion 34 having the above-described configuration may further have the following configuration. Here, for reference to the drawings, the description will be made only with respect to the first surface 30a side, but the second surface 30b side (liquid flow path groove 36, convex portion 36a, and communication opening 36b) can be considered in the same way. However, this does not mean that the shape of the first surface 30a side and the shape of the second surface 30b side need to be the same, and the shapes of the first surface 30a side and the second surface 30b side may be the same or different.

[0043] The width of the outer peripheral liquid flow path portion 34 indicated by W2 in FIGS. 3 to 5 and FIG. 7(a) (the size in the direction in which the liquid flow path grooves 35 and 36 are arranged) can be appropriately set according to the size of the entire vapor chamber and the like. However, the width W2 is preferably 3.0 mm or less, may be 1.5 mm or less, and may be 1.0 mm or less. If the width W2 exceeds 3.0 mm, there is a possibility that sufficient space for the inner liquid flow path and vapor flow path cannot be secured. On the other hand, the width W2 is preferably 0.05 mm or more, may be 0.1 mm or more, and may be 0.2 mm or more. If the width W2 is less than 0.05 mm, there is a possibility that a sufficient amount of the liquid refluxing outside cannot be obtained. The range of the width W2 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Also, the range of the width W2 may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values. Here, although the widths of both the first surface 30a side and the second surface 30b side of the outer peripheral liquid flow path portion 34 are indicated by W2, the widths of the outer peripheral joint surface 33a and the outer peripheral joint surface 33b do not necessarily have to be the same, and may be different widths.

[0044] Regarding the liquid flow path groove 35, the groove width (the size in the direction in which the liquid flow path grooves 35 are arranged, the width on the opening surface of the groove) indicated by W3 in FIGS. 7(a) and 8 is preferably 1000 μm or less, may be 500 μm or less, or may be 200 μm or less. On the other hand, the width W3 is preferably 20 μm or more, may be 45 μm or more, or may be 60 μm or more. The range of the width W3 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Also, the range of the width W3 may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values. Also, the depth of the groove indicated by D1 in FIG. 7(a) is preferably 200 μm or less, may be 150 μm or less, or may be 100 μm or less. On the other hand, the depth D1 is preferably 5 μm or more, may be 10 μm or more, or may be 20 μm or more. The range of the depth D1 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Also, the range of the depth D1 may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values. By configuring as described above, the capillary force of the condensate flow path required for reflux can be more strongly exerted.

[0045] From the viewpoint of more strongly exerting the capillary force of the condensate flow path, the aspect ratio (length-to-width ratio) in the flow path cross-section represented by the value obtained by dividing the groove width W3 by the depth D1 is preferably greater than 1.0. This ratio may be 1.5 or more, or may be 2.0 or more. Alternatively, the aspect ratio may be less than 1.0. This ratio may be 0.75 or less, or may be 0.5 or less. Among them, from the viewpoint of manufacturing, W3 is preferably larger than D1, and from such a viewpoint, the aspect ratio is preferably greater than 1.3.

[0046] In addition, the pitch between adjacent liquid flow path grooves 35 in the plurality of liquid flow path grooves 35 indicated by P1 in FIG. 7(a) is preferably 1100 μm or less, may be 550 μm or less, or may be 220 μm or less. On the other hand, the pitch P1 is preferably 30 μm or more, may be 55 μm or more, or may be 70 μm or more. The range of this pitch P1 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Further, the range of the pitch P1 may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values. Thereby, while increasing the density of the condensate flow path, it is possible to suppress the deformation during joining or assembly and the collapse of the condensate flow path.

[0047] Regarding the communication opening 35b, the size of the opening along the direction in which the liquid flow path groove 35 indicated by L1 in FIG. 8 extends is preferably 1100 μm or less, may be 550 μm or less, or may be 220 μm or less. On the other hand, the size L1 is preferably 30 μm or more, may be 55 μm or more, or may be 70 μm or more. The range of the size L1 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Further, the range of the size L1 may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values.

[0048] Further, the pitch of adjacent communication openings 35b in the direction in which the liquid flow path groove 35 shown by L2 in FIG. 8 extends is preferably 2700 μm or less, may be 1800 μm or less, or may be 900 μm or less. On the other hand, this pitch L2 is preferably 60 μm or more, may be 110 μm or more, or may be 140 μm or more. The range of this pitch L2 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Further, the range of the pitch L2 may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values.

[0049] Regarding the introduction part 37, the protrusion amount (the distance from the end of the convex part 35a to the top 37a) shown by W4 in FIG. 7(a) is preferably 1000 μm or less, may be 500 μm or less, or may be 300 μm or less. On the other hand, the protrusion amount W4 is preferably 20 μm or more, may be 45 μm or more, or may be 60 μm or more. The range of the protrusion amount W4 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Further, the range of the protrusion amount W4 may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values.

[0050] <<Inner liquid flow path part>> Returning to FIGS. 1 to 5, the inner liquid flow path part 38 will be described. The inner liquid flow path part 38 also functions as a liquid flow path part and is a part of the condensate flow path 3, which is a second flow path through which the working fluid passes when it condenses and liquefies, and a part that constitutes the introduction part 41. FIGS. 13(a) and 13(b) show an enlarged view of the part indicated by the arrow C5 in FIG. 5. The cross-sectional shape of the inner liquid flow path part 38 also appears in FIGS. 13(a) and 13(b). Further, FIG. 14 shows an enlarged plan view of the inner liquid flow path part 38 viewed from the direction indicated by the arrow C6 in FIG. 13. Here, FIG. 13(a) is a cross-sectional view taken along the line C 17 -C 17 in FIG. 14, and FIG. 13(b) is a cross-sectional view taken along the line C 18 -C18 It is a cross-sectional view taken along the arrow. Fig. 13(a) is a cross-section where the convex portion 39a is arranged on the introduction portion 41 side, and Fig. 13(b) is a cross-section where the communication opening 39b is arranged on the introduction portion 41 side.

[0051] As can be seen from these figures, the inner liquid flow path portion 38 is a portion formed inside the annular outer peripheral liquid flow path portion 34 in the main body 31. The inner liquid flow path portion 38 of the present embodiment extends in a direction (x direction) parallel to the long side of the rectangle in the plan view of the main body 31 (when viewed from the z direction), and a plurality (three in the present embodiment) of inner liquid flow path portions 38 are arranged at a predetermined interval in a direction (y direction) parallel to the short side.

[0052] On each of the first surface 30a and the second surface 30b of the inner liquid flow path portion 38, a plurality of grooves extending along the direction in which the inner liquid flow path portion 38 extends, i.e., the liquid flow path groove 39 (on the first surface 30a side) and the liquid flow path groove 40 (on the second surface 30b side), are formed, and the plurality of liquid flow path grooves 39 and 40 are arranged at a predetermined interval in a direction different from the direction in which the liquid flow path grooves 39 and 40 extend. Therefore, as can be seen from Fig. 13 and the like, in the inner liquid flow path portion 38, in its cross-section, the liquid flow path groove 39 which is a concave portion on the first surface 30a side and the convex portion 39a between the liquid flow path grooves 39 are formed by repeating concavities and convexities. Further, on the second surface 30b side, the liquid flow path groove 40 which is a concave portion and the convex portion 40a between the liquid flow path grooves 40 are formed by repeating concavities and convexities. That is, in the present embodiment, the liquid flow path grooves serving as the condensate flow path 3 are provided on both the one side and the other side (front and back) in the thickness direction (z direction).

[0053] In this way, by providing the plurality of liquid flow path grooves 39 and 40 on each of the first surface 30a and the second surface 30b, the flow path cross-sectional area of the condensate flow path 3 as a whole is ensured to be an appropriate size, and the condensate with the required flow rate can flow. At the same time, the depth and width of each liquid flow path groove 39 and 40 are reduced, and the flow path cross-sectional area of the condensate flow path 3 which is the second flow path (see Fig. 18 etc.) can be reduced to utilize a large capillary force.

[0054] Here, since the liquid flow path grooves 39 and 40 are grooves, in their cross-sectional shape, they have a bottom, and the opposite side facing this bottom is open. As will be described later, when the first sheet 10 and the second sheet 20 are stacked on the third sheet 30, this opening is blocked to form the condensate flow path 3. In this embodiment, the cross-sections of the liquid flow path grooves 39 and 40 are semi-elliptical. However, the cross-sectional shape is not limited to a semi-elliptical shape, and may be a circular shape, a rectangular shape, a square shape, a trapezoidal shape or other quadrilateral shapes, other polygons, or a combination of any of these.

[0055] Furthermore, in this embodiment, in the inner liquid flow path portion 38, as can be seen from FIG. 14, adjacent liquid flow path grooves 39 communicate with each other through communication openings 39b at a predetermined interval. As a result, the equalization of the condensate amount among the plurality of liquid flow path grooves 39 is promoted, the condensate can flow efficiently, and a smooth reflux of the working fluid is possible. Note that FIG. 14 shows the first surface 30a side, so the liquid flow path groove 39, the convex portion 39a, and the communication opening 39b will be described. However, the liquid flow path groove 40 and the convex portion 40a provided on the second surface 30b side can be considered in the same way, and communication openings 40b (not shown) are provided, and they can be considered in the same way as the liquid flow path groove 39, the convex portion 39a, and the communication opening 39b. Also, regarding this communication opening 39b, similar to the above-described communication opening 35b, following the example shown in FIG. 9, the communication opening 39b may be arranged so as to be at the same position along the direction orthogonal to the direction in which the liquid flow path grooves 39 and 40 extend. Also, the shape of the communication opening 39b and the convex portion 39a following the examples of FIGS. 10 to 12 may be used.

[0056] Also, in this embodiment, an introduction portion 41 is provided in the inner liquid flow path portion 38. The introduction portion 41 is a portion formed at the boundary surface with the vapor flow path groove 42 and is a portion protruding toward the vapor flow path groove 42 side. In this embodiment, it has a top portion 41a that protrudes most at the center in the thickness direction (z direction), and from the top portion 41a toward the first surface 30a and the second surface 30b sides (z direction), an introduction surface 41b that is concave in an arc shape toward the inner liquid flow path portion 38 side is provided in a cross-sectional view. The form of the introduction part 41 is not limited to this. The position of the top part 41a may be anywhere in the z direction. The introduction surface 41b may be a straight line in cross section, or a curve that is not arc-shaped. Also, the top part 41a may be a point in cross section or may have a length.

[0057] According to such an introduction part 41, due to the above-described shape, the condensed liquid easily gathers on the introduction surface 41b, and the movement of the working fluid between the condensed liquid flow path 3 and the vapor flow path 4 through the introduction part 41 becomes smooth, and the heat transport capacity can be further enhanced.

[0058] The inner liquid flow path part 38 having the above-described configuration preferably further has the following configuration. The width of the inner liquid flow path part 38 (the largest value in the direction in which the inner liquid flow path part 38 and the vapor flow path groove 42 are arranged, shown as W5 in FIGS. 3, 4, 5, and 13(a)) is preferably 3000 μm or less, may be 2000 μm or less, and may be 1500 μm or less. On the other hand, this width W5 is preferably 100 μm or more, may be 200 μm or more, and may be 400 μm or more. The range of this width W5 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Also, the range of the width W5 may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values.

[0059] Also, the pitch of the plurality of inner liquid flow path parts 38 (shown as P2 in FIGS. 3 and 5) is preferably 5000 μm or less, may be 3500 μm or less, and may be 3000 μm or less. On the other hand, this pitch P2 is preferably 200 μm or more, may be 400 μm or more, and may be 800 μm or more. The range of this pitch P2 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Also, the range of the pitch P2 may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values. This reduces the flow resistance of the vapor flow path, enabling the vapor to move and the condensate to flow back in a well-balanced manner.

[0060] The inner liquid flow path portion 38 having the above-described configuration may further have the following configuration. Here, for the purpose of referring to the drawings, only the first surface 30a side will be described, but the second surface 30b side (liquid flow path groove 40, convex portion 40a, and communication opening 40b) can be considered in the same way. However, this does not necessarily mean that the shape of the first surface 30a side and the shape of the second surface 30b side need to be the same. The shapes of the first surface 30a side and the second surface 30b side may be the same or different.

[0061] Regarding the liquid flow path groove 39, the groove width (the size in the direction in which the liquid flow path grooves 39 are arranged, which is the width on the opening surface of the groove) shown by W6 in FIGS. 13(a) and 14 is preferably 1000 μm or less, may be 500 μm or less, and may be 200 μm or less. On the other hand, this width W6 is preferably 20 μm or more, may be 45 μm or more, and may be 60 μm or more. The range of this width W6 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Also, the range of the width W6 may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values.

[0062] Also, the depth of the liquid flow path groove 39 shown by D2 in FIG. 13(a) is preferably 200 μm or less, may be 150 μm or less, and may be 100 μm or less. On the other hand, this depth D2 is preferably 5 μm or more, may be 10 μm or more, and may be 20 μm or more. The range of this depth D2 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Also, the range of the depth D2 may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values. This can strongly exert the capillary force of the condensate flow path required for reflux.

[0063] From the viewpoint of more strongly exerting the capillary force of the flow path, the aspect ratio (length-width ratio) in the flow path cross-section represented by the value obtained by dividing the groove width W6 by the depth D2 is preferably greater than 1.0. It may be 1.5 or more, or may be 2.0 or more. Or it may be smaller than 1.0, may be 0.75 or less, or may be 0.5 or less. Among them, from the manufacturing viewpoint, the groove width W6 is preferably greater than the depth D2, and from this viewpoint, the aspect ratio is preferably greater than 1.3.

[0064] Also, the pitch of adjacent liquid flow path grooves 39 in the plurality of liquid flow path grooves 39 indicated by P3 in FIG. 13(a) is preferably 1100 μm or less, may be 550 μm or less, or may be 220 μm or less. On the other hand, this pitch P3 is preferably 30 μm or more, may be 55 μm or more, or may be 70 μm or more. The range of this pitch P3 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Also, the range of the pitch P3 may be determined by combining any two of the plurality of upper limit candidate values, or by combining any two of the plurality of lower limit candidate values. This can suppress the deformation and collapse of the flow path during bonding or assembly while increasing the density of the condensate flow path.

[0065] Furthermore, regarding the communication opening 39b, the size of the opening along the direction in which the liquid flow path groove 39 shown by L3 in FIG. 14 extends is preferably 1100 μm or less, may be 550 μm or less, or may be 220 μm or less. On the other hand, this size L3 is preferably 30 μm or more, may be 55 μm or more, or may be 70 μm or more. The range of this size L3 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Also, the range of the size L3 may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values.

[0066] Also, the pitch of adjacent communication openings 39b in the direction in which the liquid flow path groove 39 shown by L4 in FIG. 14 extends is preferably 2700 μm or less, may be 1800 μm or less, or may be 900 μm or less. On the other hand, this pitch L4 is preferably 60 μm or more, may be 110 μm or more, or may be 140 μm or more. The range of this pitch L4 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Also, the range of this pitch L4 may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values.

[0067] The liquid flow path grooves 35 and 36, and the liquid flow path grooves 39 and 40 of the above-described embodiment are arranged at equal intervals and parallel to each other, but it is not limited thereto. As long as capillary action can be achieved, the pitch between the grooves may vary, and the grooves do not have to be parallel to each other.

[0068] Regarding the introduction part 41, the protruding amount (the distance from the end of the convex part 39a to the top 41a) shown by W7 in Fig. 13(a) is preferably 1000 μm or less, may be 500 μm or less, or may be 300 μm or less. On the other hand, the protruding amount W7 is preferably 20 μm or more, may be 45 μm or more, or may be 60 μm or more. The range of the protruding amount W7 may be determined by a combination of any one of the plurality of candidate upper limit values and one of the plurality of candidate lower limit values. Further, the range of the protruding amount W7 may be determined by combining any two of the plurality of candidate upper limit values or by combining any two of the plurality of candidate lower limit values.

[0069] <<Steam flow path groove>> Next, the steam flow path groove 42 will be described. The steam flow path groove 42 is a part of the steam flow path 4 (see Fig. 15 etc.), which is the first flow path, through which the steam evaporated from the working fluid passes. The shape of the steam flow path groove 42 in plan view is shown in Figs. 3 and 4, and the cross-sectional shape of the steam flow path groove 42 is shown in Fig. 5.

[0070] As can be seen from these figures, in this embodiment, the steam flow path groove 42 is constituted by a groove (slit) formed inside the annular shape of the outer peripheral liquid flow path portion 34 in the main body 31. Specifically, the steam flow path groove 42 of this embodiment is formed between adjacent inner liquid flow path portions 38 and between the outer peripheral liquid flow path portion 34 and the inner liquid flow path portion 38, and is a groove extending in the direction (x direction) parallel to the long side of the rectangular shape of the main body 31 in plan view. And a plurality (four in this embodiment) of steam flow path grooves 42 are arranged in the direction (y direction) parallel to the short side. The steam flow path groove 42 of this embodiment is configured to communicate the first surface 30a and the second surface 30b side of the third sheet 30, that is, it is a slit-shaped groove, penetrates the third sheet 30 in the thickness direction, opens to the first surface 30a and the second surface 30b side, and extends along the sheet surface (the first surface 30a, the second surface 30b) of the third sheet 30 and is extending. Therefore, as can be seen from Fig. 5, the third sheet 30 has a shape in which the outer peripheral liquid flow path portion 34, the inner liquid flow path portion 38, and the steam flow path groove 42 are alternately repeated in the y direction.

[0071] The steam flow path groove 42 having such a configuration can further have the following configuration. The width of the steam flow path groove 42 indicated by W8 in FIGS. 3, 4, and 5 (the size in the direction in which the inner liquid flow path portion 38 and the steam flow path groove 40 are arranged, that is, the width on the opening surface of the steam flow path groove) is formed to be larger than at least the widths W3 of the above-described liquid flow path grooves 35 and 37, and the widths W6 of the liquid flow path grooves 39 and 40, and is preferably 2500 μm or less, may be 2000 μm or less, or may be 1500 μm or less. On the other hand, this width W8 is preferably 100 μm or more, may be 200 μm or more, or may be 400 μm or more. The range of this width W8 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Further, the range of the width W8 may be determined by combining any two of the plurality of upper limit candidate values or by combining any two of the plurality of lower limit candidate values. The pitch of the steam flow path groove 42 is usually determined by the pitch of the inner liquid flow path portion 38. By making the flow path cross-sectional area of the steam flow path groove larger than that of the liquid flow path groove, it is possible to smoothly reflux steam, which has a larger volume than the condensate due to the nature of the working fluid.

[0072] In this embodiment, the cross-sectional shape of the steam flow path groove 42 is based on the introduction portions 37 and 41. However, when the introduction portion 41 is not provided, it may be a quadrangle such as a rectangle, a square, a trapezoid, a triangle, or a shape formed by combining any plurality of these. Since the steam flow path can cause smooth reflux of the working fluid by reducing the flow resistance of the steam, the shape of the flow path cross-section can also be determined from such a viewpoint.

[0073] In this embodiment, an example in which one steam flow path groove 42 is formed between adjacent inner liquid flow path portions 38 has been described. However, the present invention is not limited to this, and a form in which two or more steam flow path grooves are arranged side by side between adjacent inner liquid flow path portions may also be used.

[0074] <<Steam flow path communication groove>> The steam flow path communication groove 44 is a groove that connects a plurality of steam flow path grooves 42. As a result, the steam in the plurality of steam flow path grooves 42 can be equalized, the steam can be carried over a wider range, and many condensate flow paths 3 can be efficiently utilized, so that the reflux of the working fluid can be made smoother.

[0075] As can be seen from FIGS. 3, 4, and 6, the steam flow path communication groove 44 of this embodiment is formed between the inner liquid flow path portion 38, both end portions in the direction in which the steam flow path grooves 42 extend, and the outer peripheral liquid flow path portion 34.

[0076] The steam flow path communication groove 44 is formed so as to connect adjacent steam flow path grooves 42. As can be seen from FIG. 6 in this embodiment, the steam flow path communication groove 44 has a groove 44a on the first surface 30a side and a groove 44b on the second surface 30b side, and is provided with a connecting portion 44c between the groove 44a and the groove 44b. This connecting portion 44c connects the inner liquid flow path portion 38 and the outer peripheral liquid flow path portion 33 and holds the inner liquid flow path portion 38. Also, as shown in FIGS. 3 and 4, in this embodiment, at the portion where the end of the groove 32a provided in the injection portion 32 of the third sheet 30 is arranged among the steam flow path communication grooves 44, a hole 44d is provided in the connecting portion 44c, and the groove 44a and the groove 44b communicate with each other. This enables smoother injection of the working fluid without hindering the injection of the working fluid from the groove 32a.

[0077] The steam flow path communication groove 44 only needs to connect a plurality of steam flow path grooves 42, and its shape is not particularly limited. For example, it can have the following configuration. The width of the steam flow path communication groove 44 shown by W9 in FIGS. 3, 4, and 6 (the size in the direction perpendicular to the communication direction, that is, the width on the opening surface of the groove) is preferably 2500 μm or less, may be 2000 μm or less, and may be 1500 μm or less. On the other hand, this width W9 is preferably 100 μm or more, may be 200 μm or more, and may be 400 μm or more. The range of this width W9 may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Further, the range of the width W9 may be determined by combining any two of the plurality of upper limit candidate values, or by combining any two of the plurality of lower limit candidate values.

[0078] In this embodiment, the cross-sectional shapes of the grooves 44a and 44b of the steam flow path communication groove 44 are semi-elliptical, but are not limited thereto, and may be quadrilaterals such as rectangles, squares, trapezoids, triangles, semi-circles, with a semi-circular bottom, a semi-elliptical bottom, or a combination of any of these. Since the steam flow path communication groove can make the working fluid flow back smoothly by reducing the flow resistance of the steam, the shape of the flow path cross-section can also be determined from this perspective.

[0079] <Structure of the vapor chamber> Next, the structure when the first sheet 10, the second sheet, and the third sheet 30 are combined to form the vapor chamber 1 will be described. Through this description, the shape of the vapor chamber 1 and the arrangement, size, shape, etc. of each component that the first sheet 10, the second sheet, and the third sheet 30 should have will be further understood.

[0080] FIG. 15 shows a cross-sectional view of the vapor chamber 1 cut in the thickness direction along the y direction shown by C7-C7 in FIG. 1. FIG. 16 shows a cross-sectional view of the vapor chamber 1 cut in the thickness direction along the x direction shown by C8-C8 in FIG. 1. FIG. 17(a) shows a cross-section corresponding to FIG. 7(a) at the portion shown by C9 in FIG. 15, FIG. 17(b) shows a cross-section corresponding to FIG. 7(b), and FIG. 18(a) shows C in FIG. 15 10The cross-section corresponding to FIG. 13(a) in the part shown by and the cross-section corresponding to FIG. 13(b) in FIG. 18(b) are respectively shown. In the cross-sections shown in FIGS. 15, 16, 17(a), and 18(a), the vapor flow path 4 and the vapor flow path 3 are separated by the convex portions 35a and 39a. However, as described with reference to FIGS. 8 and 14, the convex portions 35a and 39a are each provided with a communication opening 35b and a communication opening 39b. Therefore, according to the cross-sections in FIGS. 17(b) and 18(b) where the communication openings 35b and 39b are in contact with the vapor flow path 4, the vapor flow path 4 and the vapor flow path 3 communicate with each other through the communication openings 35b and 39b.

[0081] As can be seen from FIGS. 1, 2, and 15 to 18, the inner surface 10a of the first sheet 10 is overlapped on the first surface 30a side of the third sheet 30, and the inner surface 20a of the second sheet 20 is overlapped on the second surface 30b side of the third sheet 30 and is arranged and joined to form the vapor chamber 1. At this time, the main body 31 of the third sheet 30 overlaps with the main body 11 of the first sheet 10, and the main body 31 of the third sheet 30 overlaps with the main body 21 of the second sheet 20. The injection portion 32 of the third sheet 30 overlaps with the injection portion 12 of the first sheet 10, and the injection portion 32 of the third sheet 30 overlaps with the injection portion 22 of the second sheet 20.

[0082] With such a laminate of the first sheet 10, the second sheet 20, and the third sheet 30, each component provided in the main body 11, the main body 21, and the main body 31 is arranged as shown in FIGS. 15, 16, 17(a), 17(b), 18(a), and 18(b). Specifically, it is as follows.

[0083] The outer peripheral joint surface 33a provided on the first surface 30a side of the third sheet 30 is arranged so as to overlap with the surface of the outer peripheral portion of the inner surface 10a of the first sheet 10, and the outer peripheral joint surface 33b provided on the second surface 30b side of the third sheet 30 is arranged so as to overlap with the surface of the outer peripheral portion of the inner surface 20a of the second sheet 20, and they are joined by joining means such as diffusion bonding or brazing. As a result, a hollow portion based on the shape of the third sheet 30 is formed between the first sheet 10 and the second sheet 20, and by enclosing a working fluid therein, a sealed space 2 is formed.

[0084] The inner surface 10a of the first sheet 10 is arranged so as to overlap with the first surface 30a side of the outer peripheral fluid flow path portion 34 of the third sheet 30. As a result, the opening of the fluid flow path groove 35 is blocked by the first sheet 10 and becomes a part of the hollow portion. This is a condensate flow path 3 which is a second flow path through which condensate, which is a state in which the working fluid enclosed in the hollow portion has condensed and liquefied, flows. Similarly, the inner surface 20a of the second sheet 20 is arranged so as to overlap with the second surface 30b side of the outer peripheral fluid flow path portion 34 of the third sheet 30. As a result, the opening of the fluid flow path groove 36 is blocked by the second sheet 20 and becomes a part of the hollow portion. This is a condensate flow path 3 which is a second flow path through which condensate, which is a state in which the working fluid enclosed in the hollow portion has condensed and liquefied, flows.

[0085] Also, the inner surface 10a of the first sheet 10 is arranged so as to overlap with the first surface 30a side of the inner peripheral fluid flow path portion 38 of the third sheet 30. As a result, the opening of the fluid flow path groove 39 is blocked by the first sheet 10 and becomes a part of the hollow portion. This is a condensate flow path 3 which is a second flow path through which condensate, which is a state in which the working fluid enclosed in the hollow portion has condensed and liquefied, flows. Similarly, the inner surface 20a of the second sheet 20 is arranged so as to overlap with the second surface 30b side of the outer peripheral fluid flow path portion 38 of the third sheet 30. As a result, the opening of the fluid flow path groove 40 is blocked by the second sheet 20 and becomes a part of the hollow portion. This is a condensate flow path 3 which is a second flow path through which condensate, which is a state in which the working fluid enclosed in the hollow portion has condensed and liquefied, flows.

[0086] In this way, by forming a narrow flow path surrounded by walls on all four sides in the cross section, the condensed liquid is moved by a strong capillary force, enabling smooth circulation. That is, when considering a flow path assuming the flow of the condensed liquid, compared to a so-called groove-type flow path in which one surface of the flow path is continuously open, a higher capillary force can be obtained according to the condensed liquid flow path 3. Further, since the condensed liquid flow path 3 is formed separately from the vapor flow path 4 which is the first flow path, the circulation of the working fluid can be made smooth.

[0087] Furthermore, in this embodiment, the condensed liquid flow path 3 formed by the liquid flow path grooves 35 and 39 and the condensed liquid flow path 3 formed by the liquid flow path grooves 36 and 40 are provided, and the condensed liquid flow path 3 is provided on each of one side and the other side in the thickness direction (z direction) of the vapor chamber 1. Thereby, while reducing (narrowing) the flow path cross-sectional area of one condensed liquid flow path 3, the total flow path cross-sectional area of the condensed liquid flow path 3 can be made large, so that the flow of the condensed liquid can be made smooth while maintaining a high capillary force. Also, not only the in-plane direction (xy direction) movement of the working fluid in the vapor chamber 1 but also the opportunity for movement in the thickness direction (z direction) can be given, and more uniform heat transfer and heat transport can be expected.

[0088] The shape of the condensed liquid flow path 3 can be considered based on the shape and dimensions described in the above-mentioned third sheet 30.

[0089] The other parts will be described. As can be seen from FIG. 15, the opening of the vapor flow path groove 42 is blocked by the first sheet 10 and the second sheet 20 to form a part of the hollow portion, which becomes the flow path of the enclosed working fluid and becomes the vapor flow path 4 which is the first flow path through which vapor flows. Here, the surfaces of the first sheet 10 and the second sheet 20 on the vapor flow path 4 side that constitute a part of the vapor flow path 4 are preferably flat. In this embodiment, since the surfaces of the first sheet 10 and the second sheet 20 are not processed and have flat plate surfaces, the inner wall of the vapor flow path 4 becomes smooth, and the resistance when the vapor moves can be suppressed.

[0090] The flow channel cross-sectional area of the condensate flow channel 3, which is the second flow channel described above, is made smaller than the flow channel cross-sectional area of the vapor flow channel 4, which is the first flow channel. More specifically, the average flow channel cross-sectional area of two adjacent vapor flow channels 4 (in this embodiment, the flow channel surrounded by one vapor flow channel groove 42, the first sheet 10, and the second sheet 20) is A g Let it be, and the average flow channel cross-sectional area of a plurality of condensate flow channels 3 (in this embodiment, one inner liquid flow channel portion 38 and a plurality of condensate flow channels 3 surrounded by the first sheet 10 and the second sheet 20) arranged between two adjacent vapor flow channels 4 is A l When it is, the condensate flow channel 3 and the vapor flow channel 4 are such that A l is 0.5 times or less of A g , preferably 0.25 times or less. Thereby, the working fluid becomes more likely to selectively pass through the first flow channel and the second flow channel depending on its phase state (gas phase, liquid phase). This relationship only needs to be satisfied in at least a part of the entire vapor chamber, and it is more preferable if this is satisfied throughout the entire vapor chamber.

[0091] The shape of the vapor flow channel 4 can be considered based on the shape and dimensions described for the third sheet 30 above. In addition, in this embodiment, since the introduction part 37 and the introduction part 41 are provided, one vapor flow channel 4 is configured to be in contact with two introduction parts.

[0092] As can be seen from FIG. 16, openings of the grooves 44a of the vapor flow channel communication grooves 44 of the third sheet 30 are blocked by the first sheet 10, and openings of the grooves 44b are blocked by the second sheet 20, respectively, to form a hollow part in which a plurality of vapor flow channels 4 communicate with each other, which serves as a flow channel for the working fluid.

[0093] As shown in FIGS. 1 and 2 for the injection part 12, injection part 22, and injection part 32, the injection part 12 overlaps the first surface 30a side of the injection part 32, and the injection part 22 overlaps the second surface 30 side of the injection part 32. The opening of the injection groove 32a on the second surface 30b side of the third sheet 30 is blocked by the injection part 22 of the second sheet 20, and an injection flow path 5 that communicates the outside with the hollow part (condensate flow path 3 and vapor flow path 4) is formed. However, after injecting the working fluid from the injection flow path 5 into the hollow part, the injection flow path 5 is closed to form a sealed space 2. Therefore, in the final form of the vapor chamber 1, the outside and the hollow part do not communicate with each other. In this embodiment, an example is shown in which the injection part 12, injection part 22, and injection part 32 are provided at one end of a pair of ends in the longitudinal direction of the vapor chamber 1. However, the present invention is not limited to this, and they may be arranged at any other end, or a plurality of them may be arranged. When a plurality of them are arranged, for example, they may be arranged at each of a pair of ends in the longitudinal direction of the vapor chamber 1, or may be arranged at one end of the other pair of ends.

[0094] The working fluid is enclosed in the sealed space 2 of the vapor chamber 1. The type of the working fluid is not particularly limited, and a working fluid used in a normal vapor chamber such as pure water, ethanol, methanol, acetone, and a mixture thereof can be used.

[0095] [Manufacture of vapor chamber] The vapor chamber as described above can be manufactured, for example, as follows. For a sheet having the outer peripheral shape of the third sheet 30, the liquid flow path groove 35, liquid flow path groove 36, liquid flow path groove 39, liquid flow path groove 40, vapor flow path groove 42, and grooves 44a and 44b are formed by half etching. Half etching means etching only up to the middle without penetrating in the thickness direction. However, for the vapor flow path groove 42, half etching is performed from both the first surface 30a side and the second surface 30b side so as to penetrate in the thickness direction. By etching in this way, the shapes of the introduction part 37 and the introduction part 41 can be formed.

[0096] Next, the first sheet 10 is overlapped on the first surface 30a side of the third sheet 30, and the second sheet 20 is overlapped on the second surface 30b side of the third sheet 30 and temporarily fixed. The method of temporary fixing is not particularly limited, and examples thereof include resistance welding, ultrasonic welding, and adhesion with an adhesive. After temporary fixing, diffusion bonding is performed to permanently bond the first sheet 10, the second sheet 20, and the third sheet 30 to form a vapor chamber sheet. Note that brazing may be used for bonding instead of diffusion bonding. Here, "permanently bonded" is not strictly defined, and it means that the bonding can be maintained to such an extent that the airtightness of the sealed space 2 can be maintained during the operation of the vapor chamber 1.

[0097] After bonding, evacuation is performed through the formed injection channel 5 to reduce the pressure in the hollow portion. Then, the working fluid is injected into the depressurized hollow portion through the injection channel 5 so that the working fluid enters the hollow portion. Then, the injection channels 5 are closed by welding using melting or caulking on the overlapping injection portions 12, injection portions 22, and injection portions 32 to form a sealed space. As a result, the working fluid is stably held inside the sealed space 2.

[0098] In the vapor chamber of this embodiment, since the internal liquid flow path portion 38 functions as a support, it is possible to prevent the sealed space from being crushed during bonding and depressurization.

[0099] In the above, the manufacturing of the vapor chamber by etching has been described, but the manufacturing method is not limited to this, and the vapor chamber can also be manufactured by press working, cutting, laser processing, and processing by a 3D printer. For example, when manufacturing a vapor chamber by a 3D printer, it is not necessary to manufacture the vapor chamber by bonding a plurality of sheets, and a vapor chamber without a bonding portion can be obtained.

[0100] [Structure of Electronic Device and Action of Vapor Chamber] Next, the operation of the vapor chamber 1 will be described. FIG. 19 schematically shows a state in which the vapor chamber 1 is disposed inside a portable terminal 80, which is a form of an electronic device. Here, since the vapor chamber 1 is disposed inside the housing 81 of the portable terminal 80, it is represented by a dotted line. Such a portable terminal 80 includes a housing 81 that houses various electronic components and a display unit 82 that is exposed to the outside so that an image can be seen through an opening of the housing 81. And as one of these electronic components, an electronic component 53 to be cooled by the vapor chamber 1 is disposed in the housing 51.

[0101] The vapor chamber 1 is installed in a housing such as a portable terminal and is attached to an electronic component 83, which is an object to be cooled such as a CPU. The electronic component is attached to the outer surface of the vapor chamber 1 directly or via a highly thermally conductive adhesive, sheet, tape, etc. There is no particular limitation on the position where the electronic component 83 is attached to the vapor chamber, and it is appropriately set according to the relationship with the arrangement of other members in a portable terminal or the like. In this embodiment, as shown by the dotted line in FIG. 1, the electronic component 53 is disposed at the center in the xy direction of the main body 21 on the surface of the second sheet 20 opposite to the side where the third sheet 30 is disposed. Therefore, in FIG. 1, the electronic component 83 is represented by a dotted line because it is in a position where it cannot be seen as a blind spot. FIG. 20 shows a diagram for explaining the flow of the working fluid. For ease of explanation, in this figure, the first surface 30a side of the third sheet 30 is shown as being visible inside the vapor chamber 1.

[0102] When the electronic component 83 generates heat, the heat is transmitted through the second sheet 20 by heat conduction, and the condensate existing at a position close to the electronic component 83 in the sealed space 2 receives the heat. The condensate that has received this heat absorbs the heat and evaporates and vaporizes. As a result, the electronic component 83 is cooled.

[0103] The vaporized working fluid becomes vapor and flows and moves in the vapor flow path 4 as shown by the solid straight arrow in FIG. 20. Since this flow occurs in a direction away from the electronic component 83, the vapor moves in a direction away from the electronic component 83. The vapor in the vapor flow path 4 moves away from the electronic component 83 which is the heat source, and moves to the outer peripheral part of the vapor chamber 1 where the temperature is relatively low. During this movement, it is cooled while sequentially losing heat to the first sheet 10, the second sheet 20, and the third sheet 30. The first sheet 10, the second sheet 20, and the third sheet 30 that have taken heat from the vapor transfer the heat to the housing 81 etc. of the electronic device 80 in contact with the vapor chamber, and finally the heat is released to the outside air.

[0104] The working fluid that has been losing heat while moving through the vapor flow path 4 condenses and liquefies. This condensate adheres to the wall surface of the vapor flow path 4. On the other hand, since vapor is continuously flowing through the vapor flow path 4, the condensate moves to the condensate flow path 3 as being pushed by the vapor as shown by the arrow C in FIG. 18. 11 The condensate flow path 3 of this embodiment is provided with communication openings 35b, communication openings 36b, communication openings 39b, and communication openings 40b as shown in FIGS. 8 and 14. Therefore, the condensate is distributed to a plurality of condensate flow paths 3 through these communication openings.

[0105] In this embodiment, since the condensate flow path 3 is provided on both sides in the thickness direction of the vapor chamber 1, the opportunity for the movement from the vapor flow path 4 to the condensate flow path 3 can be increased, and smoother movement of the condensate becomes possible. At this time, in the form where the introduction parts 37 and 41 are provided, a part surrounded by the introduction surfaces 37b and 41b and the first sheet 10 and the second sheet 20 is generated, and the condensate tends to accumulate here due to the action of capillary force. Thereby, the introduction of the condensate into the condensate flow path 3 is performed more smoothly.

[0106] The condensate that has entered the condensate flow path 3 moves so as to approach the electronic component 83 which is the heat source as represented by the dotted straight arrow in FIG. 20 due to the capillary force by the condensate flow path and the pressure from the vapor. Then, it vaporizes again due to the heat from the electronic component 83 which is the heat source and repeats the above process.

[0107] As described above, according to the vapor chamber 1, the reflux of the condensate is good with high capillary force in the condensate flow path, and the heat transport amount can be increased. Furthermore, in the present embodiment, the condensate flow path 3 is provided on both one side and the other side in the thickness direction (z direction) of the vapor chamber 1. Thereby, while reducing (narrowing) the flow path cross-sectional area of one condensate flow path 3, the total flow path cross-sectional area of the condensate flow paths 3 can be increased, so that the flow of the condensate can be smoothed while maintaining a high capillary force. In addition, not only the in-plane direction (xy direction) movement of the working fluid in the vapor chamber 1 but also the opportunity for movement in the thickness direction (z direction) can be provided, and more uniform heat transfer and heat transport can be expected.

[0108] [Regarding the number of sheets] The vapor chamber 1 up to this point has been described with an example of being composed of three sheets, namely the first sheet 10, the second sheet 20, and the third sheet 30. By being composed of three sheets in this way, compared with the case of using more sheets, the complexity of sheet stacking is eliminated, so that manufacturing is easy, and the joining of each sheet can be made stronger. Among them, as in the present embodiment, if the surfaces of the first sheet 10 and the second sheet 20 are not processed and are in a flat form, there is no need to worry about alignment for forming the condensate flow path and the vapor flow path during sheet stacking, so that simpler manufacturing is possible.

[0109] However, regardless of the number of sheets, it is sufficient that the condensate flow paths are provided on one side and the other side in the thickness direction of the vapor chamber. The number of sheets can be four or five. In this way, by configuring the vapor chamber with three or more sheets, compared with the case of configuring it with two sheets, it becomes easier to form the introduction surface 41b as shown in FIG. 18, the working fluid is more likely to condense here, and smoother movement of the working fluid occurs. Also, for example, as shown in FIG. 21, when the third sheet is divided in the thickness direction and the vapor chamber is configured with a total of four sheets, a groove can also be formed at the center in the thickness direction of the inner liquid flow path portion 38 to provide a condensate flow path.

[0110] 1.2. Form 1b Figs. 22 to 25 show diagrams for explaining the vapor chamber 51 according to Form 1b. Fig. 22 is an exploded perspective view of the vapor chamber 51 and corresponds to Fig. 2. Fig. 23 is a diagram showing the sealed space 2 of the vapor chamber 51 and is a diagram showing the first surface 30a side of the third sheet 52. Fig. 24 is a cross-sectional view of the vapor chamber 101 cut at the position indicated by C 12 -C 12 in Fig. 23. Fig. 25 is a diagram corresponding to Fig. 18, which is an enlarged view of the periphery of the part (inner liquid flow path part 138) indicated by C 13 in Fig. 24.

[0111] In the vapor chamber 51, compared with the above-described vapor chamber 1, the third sheet 52 is applied instead of the third sheet 30, and the inner liquid flow path part 54 of the main body 53 of the third sheet 52 is provided with a thickness-direction communication hole 54a. For other members and parts, since the description of the vapor chamber 1 is applicable, the same reference numerals are given in the drawings and the description is omitted. Therefore, here, the description will focus on the thickness-direction communication hole 54a provided in the inner liquid flow path part 54.

[0112] The thickness-direction communication hole 54a is a hole provided in the inner liquid flow path part 54 of the third sheet 52 and communicating from the first surface 30a to the second surface 30b. Through this thickness-direction communication hole 54a, the liquid flow path groove 39 and the liquid flow path groove 40 are communicated, and the condensate flow path 3 on the first surface 30a side and the condensate flow path 3 on the second surface 30b side are communicated. As a result, as indicated by the arrow C 14 in Fig. 25, the condensate flow paths 3 arranged separately in the thickness direction are communicated without passing through the vapor flow path 4, and the distribution of the condensate can be further equalized, so that the working fluid can flow more smoothly.

[0113] The thickness-direction communication hole 54a only needs to be able to communicate the condensate flow paths 3 arranged on one side and the other side in the thickness direction of one inner liquid flow path portion 54, and the specific form for this purpose is not particularly limited. For example, it can be described as follows.

[0114] The cross-sectional shape of the thickness-direction communication hole 54a shown in FIGS. 22 and 23 is not particularly limited, and can be circular, elliptical, triangular, quadrilateral, other polygons, and geometric shapes formed by combining these.

[0115] Also, the shape of the thickness-direction communication hole 54a in the extending direction (z direction) shown in FIGS. 24 and 25 is not particularly limited, and the cross-sectional shape may be constant or may change at each position in the z direction. For example, a form in which the cross-sectional area is greatly expanded at the portion in contact with the condensate flow path 3 compared to other portions can be cited.

[0116] The number of condensate flow paths 3 connected by one thickness-direction communication hole 54a is not particularly limited. It may be configured such that the two condensate flow paths 3 on the first surface 30a side and the two condensate flow paths 3 on the second surface 30b side communicate as in this embodiment, or it may be configured such that one or three or more condensate flow paths 3 communicate on one side in the thickness direction.

[0117] The thickness-direction communication hole 54a will exhibit its effect if even one is provided in the vapor chamber 1, but it is preferable to provide a plurality of thickness-direction communication holes 54a for a more remarkable effect.

[0118] The mode of providing a plurality of thickness-direction communication holes 54a is not particularly limited, but it may be one for one inner liquid flow path portion 54, or a plurality of thickness-direction communication holes 54a may be provided in one inner liquid flow path portion 54. When arranging a plurality of thickness-direction communication holes 54a in one inner liquid flow path portion 54, they may be arranged in a straight line, or as shown in FIG. 23, the positions in the direction (y direction) orthogonal to the arranging direction may be shifted for adjacent thickness-direction communication holes 54a.

[0119] In the present embodiment, the thickness-direction communication holes 54a are provided only in the inner liquid flow path portion 54. Alternatively, the thickness-direction communication holes may be provided only in the outer peripheral liquid flow path portion 34, or the thickness-direction communication holes may be provided in both the inner liquid flow path portion 54 and the outer peripheral liquid flow path portion 34.

[0120] 2. Embodiment 2 2.1. Embodiment 2a [Components] FIG. 26 shows an external perspective view of the vapor chamber 101 according to Embodiment 2a, and FIG. 27 shows an exploded perspective view of the vapor chamber 101. As can be seen from FIGS. 26 and 27, the vapor chamber 101 of the present embodiment has a first sheet 10, a second sheet 20, and a third sheet 130 (which may also be referred to as the "intermediate sheet 130"). Then, as will be described later, these sheets are overlapped and joined (diffusion bonding, brazing, etc.), so that a hollow portion based on the shape of the third sheet 130 is formed between the first sheet 10 and the second sheet 20, resulting in a vapor chamber sheet. Then, by enclosing the working fluid in the hollow portion, a sealed space 102 (see, for example, FIG. 19) is formed, and the vapor chamber 101 is obtained.

[0121] Regarding the first sheet 10 and the second sheet 20 provided in the present embodiment, they can be considered in the same way as the first sheet 10 and the second sheet 20 described in Embodiment 1. Therefore, the same reference numerals are used here, and the description is omitted.

[0122] <The third sheet> In the present embodiment, the third sheet 130 is a sheet sandwiched and overlapped between the inner surface 10a of the first sheet 10 and the inner surface 20a of the second sheet 20, and has a structure for the sealed space 2 in which the working fluid moves. FIGS. 28 and 29 show a plan view of the third sheet 130 (a view seen from the z direction). FIG. 28 is a view of the surface to be overlapped with the first sheet 10, and FIG. 29 is a view of the surface to be overlapped with the second sheet 20. Also, FIG. 30 shows a cross-sectional view taken along the line indicated by C 101 -C 101 shown in FIG. 28, and FIG. 31 shows a cross-sectional view taken along the line indicated by C 102 -C 102Cross-sectional views along the lines shown are respectively shown.

[0123] Note that the third sheet 130 may also be a single layer, or may be formed by laminating a plurality of sheets. When a plurality of sheets are laminated, the following form may be formed after laminating the plurality of sheets, or the following form may be formed by individually processing the plurality of sheets and then overlapping them.

[0124] In this form, the third sheet 130 includes a first surface 130a that overlaps the inner surface 10a of the first sheet 10, a second surface 130b that overlaps the inner surface 20a of the second sheet 20, and an end surface 130c that forms a thickness across the first surface 130a and the second surface 130b. Therefore, the first surface 130a appears in FIG. 28 and the second surface 130b appears in FIG. 29, respectively.

[0125] Also, the third sheet 130 includes a main body 131 and an injection portion 32. Since the injection portion 32 of this form can be considered in the same way as the injection portion 32 shown in Form 1, the same reference numerals are given here and the description is omitted. The main body 31 is a sheet-like portion that forms a hollow portion in the vapor chamber sheet and a sealed space in the vapor chamber 1, and in this form, it is a rectangle with rounded corners (so-called R) in plan view. However, the main body 31 can be not only a quadrilateral as in this form, but also in a shape required for the vapor chamber. For example, it may be circular, elliptical, triangular, other polygons, and in a shape having a bent portion such as an L-shape, a T-shape, a crank-shaped U-shape, etc. Also, a shape combining at least two of these can be adopted.

[0126] The thickness and material of the third sheet 130 can be considered in the same way as the first sheet 10. However, the thickness and material of the third sheet 130 do not have to be the same as those of the first sheet 10, and may be configured differently.

[0127] The main body 131 is formed with a structure for the working fluid to reflux. Specifically, the main body 131 is configured to include an outer peripheral joint portion 33, an outer peripheral liquid flow path portion 134, an inner liquid flow path portion 138, a vapor flow path groove 142, and a vapor flow path communication groove 144.

[0128] The vapor chamber 101 of this embodiment includes a vapor flow path 4 (see FIG. 38 etc.) which is a first flow path and through which the vapor of the working fluid passes, and a condensate flow path 3 (see FIG. 42 etc.) which is a second flow path and through which the condensate obtained by condensing and liquefying the working fluid passes. Then, the vapor flow path groove 142 of the third sheet 130 forms the vapor flow path 4, and the liquid flow path groove 35 provided in the outer peripheral liquid flow path portion 134 and the liquid flow path groove 39 provided in the inner liquid flow path portion 138 form the condensate flow path 3.

[0129] <<Outer Peripheral Joint Portion>> The outer peripheral joint portion 33 can be considered in the same way as the outer peripheral joint portion 33 described in the above-described form 1, so the same reference numerals are given here and the description is omitted.

[0130] <<Outer Peripheral Liquid Flow Path Portion>> The outer peripheral liquid flow path portion 134 functions as a liquid flow path portion, constitutes a part of the condensate flow path 3 which is a second flow path through which the working fluid passes when it condenses and liquefies, and includes a portion that constitutes the heat insulation portion 6. FIG. 32 shows an enlarged view of the portion indicated by the arrow C in FIG. 30. 103 Also, FIG. 33 shows an enlarged view of the outer peripheral liquid flow path portion 134 viewed from the z direction as seen from the direction indicated by the arrow C in FIG. 32. That is, FIG. 33 shows a part of the outer peripheral liquid flow path portion 134 as seen from the side of the second surface 130b. 105 As can be seen from these figures, the outer peripheral liquid flow path portion 134 is formed along the inside of the outer peripheral joint portion 33 in the main body 131 and is provided along the outer periphery of the portion that becomes the sealed space 2.

[0131]

[0132] On the first surface 130a of the outer peripheral liquid flow path portion 134, liquid flow path grooves 35 which are a plurality of grooves extending parallel to the outer peripheral direction of the main body 131 are formed, and the plurality of liquid flow path grooves 35 are arranged at a predetermined interval in a direction different from the direction in which they extend.​ Since the liquid flow path groove 35 can be considered in the same manner as the liquid flow path groove 35 described in the above-described embodiment 1, the same reference numerals are given here and the description thereof is omitted.

[0133] As can be seen from FIGS. 29 to 33, in this embodiment, the outer peripheral liquid flow path portion 134 is provided with a heat insulation portion groove 136 on the second surface 30b side. The heat insulation portion groove 136 is a groove extending along the direction in which the outer peripheral liquid flow path portion 134 extends, and does not communicate with the vapor flow path groove 42 or the liquid flow path groove 35. The heat insulation portion groove 136 is configured such that the working fluid does not flow into it.

[0134] Here, since the heat insulation portion groove 136 is a groove, in its cross-sectional shape, it has a bottom, and the opposite side (second surface 130b) facing the bottom is open. As will be described later, when the second sheet 20 is stacked on the third sheet 30, this opening is blocked to form the heat insulation portion 6. In this embodiment, the cross-section of the heat insulation portion groove 136 is semi-elliptical. However, the cross-sectional shape is not limited to a semi-elliptical shape, and may be a circular shape, a rectangular shape, a square shape, a trapezoidal shape or other polygonal shapes, or a combination of any of these.

[0135] Also, FIG. 34 shows a cross-sectional view of C 106 -C 106 shown in FIG. 33. That is, FIG. 34 is a cross-sectional view of the outer peripheral liquid flow path portion 134 at the portion where the column 136a is provided. On the other hand, the cross-section shown in FIG. 32 is a cross-sectional view of the outer peripheral liquid flow path portion 134 at the portion of the heat insulation portion groove 136 where the column 136a is not arranged. As can be seen from these figures, a plurality of columns 136a standing upright from the bottom are arranged at intervals in the groove of the heat insulation groove 136. When the third sheet 130 is joined to the second sheet 20 by the column 136a, the collapse of the heat insulation portion groove 136 can be suppressed, and the strength of the vapor chamber 101 itself can also be increased.

[0136] The planar shape of the column (the shape viewed from the perspective of Fig. 33) is not particularly limited, and in addition to being quadrilateral as in this embodiment, polygons such as triangles and pentagons, circles, ellipses, or any arbitrary shape can be applied.

[0137] Also, the pitch and number of the columns to be arranged are not particularly limited and can be set as appropriate. Therefore, the number of columns can be reduced to 1 or less, and one column can be configured to be long so as to extend along the groove for the heat insulation part.

[0138] Also, in this embodiment, as shown in Fig. 30, an introduction part 37 is provided in the outer peripheral liquid flow path part 134. Since the introduction part 37 can be considered in the same way as the introduction part 37 described in Embodiment 1, the same reference numerals are given here and the description is omitted.

[0139] The outer peripheral liquid flow path part 134 having the above configuration may further have the following configuration.

[0140] In Figs. 28 to 30 and Fig. 32, W 102 The width of the outer peripheral liquid flow path part 134 shown (the size in the direction in which the liquid flow path grooves 35 are arranged) can be appropriately set according to the size of the entire vapor chamber, etc., but the width W 102 is preferably 3.0 mm or less, may be 1.5 mm or less, and may be 1.0 mm or less. When the width W 102 exceeds 3.0 mm, there is a possibility that sufficient space for the inner liquid flow path and vapor flow path cannot be obtained. On the other hand, the width W 102 is preferably 0.05 mm or more, may be 0.1 mm or more, and may be 0.2 mm or more. When the width W 102 is less than 0.05 mm, there is a possibility that a sufficient amount of liquid flowing back on the outside cannot be obtained. The range of the width W 102 may be determined by a combination of any one of the above plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Also, the range of the width W 102 may be determined by combining any two of the plurality of upper limit candidate values, or by combining any two of the plurality of lower limit candidate values. Here, the width on the first surface 130a side and the width on the second surface 130b side of the outer peripheral liquid flow path portion 134 are both denoted as W. 102 However, the width of the outer peripheral joint surface 33a and the width of the outer peripheral joint surface 33b do not necessarily have to be the same, and may be different widths.

[0141] Regarding the groove 136 for the heat insulation portion, the groove width denoted as W in FIG. 32 104 is preferably 1500 μm or less, may be 1000 μm or less, and may be 700 μm or less. On the other hand, the width W 104 is preferably 20 μm or more, may be 45 μm or more, and may be 60 μm or more. The range of the width W 104 may be determined by a combination of any one of the plurality of candidate upper limit values and one of the plurality of candidate lower limit values. Also, the range of the width W 104 may be determined by combining any two of the plurality of candidate upper limit values, or by combining any two of the plurality of candidate lower limit values. Also, the depth of the groove denoted as D in FIG. 32 102 is preferably 200 μm or less, may be 150 μm or less, and may be 100 μm or less. On the other hand, the depth D 102 is preferably 5 μm or more, may be 10 μm or more, and may be 20 μm or more. The range of the depth D 102 may be determined by a combination of any one of the plurality of candidate upper limit values and one of the plurality of candidate lower limit values. Also, the range of the depth D 102 may be determined by combining any two of the plurality of candidate upper limit values, or by combining any two of the plurality of candidate lower limit values.

[0142] <<Inner liquid flow path portion>> Returning to FIGS. 26 to 30, the inner liquid flow path portion 138 will be described. The inner liquid flow path portion 138 is also a part of the condensate flow path 3, which is a second flow path through which the working fluid passes when it condenses and liquefies, a part of the heat insulation portion 6, and a part that constitutes the introduction portion 41. In FIG. 35, arrow C in FIG. 30 107The portion indicated by is shown enlarged. The cross-sectional shapes of the inner liquid flow path portion 38, the heat insulation groove 140, and the introduction portion 41 also appear in Fig. 35. Further, Fig. 36 shows an enlarged plan view of the inner liquid flow path portion 138 viewed from the direction indicated by the arrow C in Fig. 35. 109 The enlarged plan view of the inner liquid flow path portion 138 viewed from the direction indicated by is shown.

[0143] As can be seen from these figures, the inner liquid flow path portion 138 is a portion formed inside the annular shape of the outer peripheral liquid flow path portion 134 in the main body 131. The inner liquid flow path portion 138 of the present embodiment extends in a direction (x direction) parallel to the long side of the rectangle in the plan view (when viewed from the z direction) of the main body 131, and a plurality (three in the present embodiment) of inner liquid flow path portions 138 are arranged at a predetermined interval in a direction (y direction) parallel to the short side.

[0144] A plurality of liquid flow path grooves 39, which are grooves extending along the direction in which the inner liquid flow path portion 138 extends, are formed on the first surface 130a of the inner liquid flow path portion 138, and the plurality of liquid flow path grooves 39 are arranged at a predetermined interval in a direction different from the direction in which they extend. Here, since the liquid flow path groove 39 can be considered in the same way as the liquid flow path groove 39 described in Form 1, the same reference numerals are given and the description is omitted.

[0145] As can be seen from Figs. 29, 30, 35, and 36, the inner liquid flow path portion 138 is provided with a heat insulation portion groove 140 on the second surface 130b. The heat insulation portion groove 140 is a groove extending along the direction in which the inner liquid flow path portion 138 extends, is not in communication with the vapor flow path groove 42 or the liquid flow path groove 39, and is configured such that the working fluid does not flow into the heat insulation portion groove 140.

[0146] Here, since the heat insulation portion groove 140 is a groove, in its cross-sectional shape, it has a bottom, and the opposite side (second surface 130b) facing the bottom is open. As will be described later, when the second sheet 20 is stacked on the third sheet 30, this opening is blocked to form the heat insulation portion 6. In this embodiment, the groove 140 for the heat insulation part has a semi-elliptical cross-section. However, the cross-sectional shape is not limited to a semi-elliptical shape, and may be a circular shape, a rectangular shape, a square shape, a trapezoidal shape or other quadrilateral shapes, other polygons, or a combination of any of these shapes.

[0147] Further, FIG. 37 shows a cross-sectional view taken along the line C 110 -C 110 shown in FIG. 36. That is, FIG. 37 is a cross-sectional view of the inner liquid flow path portion 138 at the portion where the column 140a is provided. On the other hand, the cross-sectional view shown in FIG. 35 is a cross-sectional view of the inner liquid flow path portion 138 at the portion of the heat insulation part groove 140 where the column 140a is not arranged. As can be seen from these figures, a plurality of columns 140a standing upright from the bottom are arranged in the groove of the heat insulation part groove 140 at intervals. When the third sheet 130 is joined to the second sheet 20 by this column 140a, the collapse of the heat insulation part groove 140 can be suppressed, and the strength of the vapor chamber 101 itself can also be increased.

[0148] The planar shape of the column (the shape from the viewpoint of FIG. 36) is not particularly limited, and in addition to being a quadrilateral as in this embodiment, polygons such as triangles and pentagons, circular shapes, elliptical shapes, or arbitrary shapes can be applied.

[0149] Also, the pitch and number of the columns to be arranged are not particularly limited and can be set as appropriate. Therefore, the number of columns may be reduced to 1 or less, and one column may be configured to be long so as to extend along the heat insulation groove.

[0150] In this embodiment, an introduction part 41 is provided in the inner liquid flow path portion 138. Since this introduction part 41 can be considered in the same way as the introduction part 41 described in the first embodiment, the same reference numerals are given and the description is omitted.

[0151] The inner liquid flow path portion 138 having the above-described configuration preferably further has the following configuration. In FIGS. 28 to 30 and FIG. 35, W 106The width of the inner liquid flow path portion 138 shown by (the largest value in the direction in which the inner liquid flow path portion 138 and the vapor flow path groove 42 are arranged) is preferably 3000 μm or less, may be 2000 μm or less, and may be 1500 μm or less. On the other hand, this width W 106 is preferably 100 μm or more, may be 200 μm or more, and may be 400 μm or more. This width W 106 range may be determined by a combination of any one of the above plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Also, the width W 106 range may be determined by combining any two of the plurality of upper limit candidate values, or by combining any two of the plurality of lower limit candidate values.

[0152] Also, in FIG. 30, the pitch of the plurality of inner liquid flow path portions 138 shown by P 102 is preferably 5000 μm or less, may be 3500 μm or less, and may be 3000 μm or less. On the other hand, this pitch P 102 is preferably 200 μm or more, may be 400 μm or more, and may be 800 μm or more. This pitch P 102 range may be determined by a combination of any one of the above plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Also, the pitch P 102 range may be determined by combining any two of the plurality of upper limit candidate values, or by combining any two of the plurality of lower limit candidate values. Thereby, the flow path resistance of the vapor flow path can be reduced, and the movement of the vapor and the reflux of the condensate can be performed in a well-balanced manner.

[0153] The inner liquid flow path portion 38 having the above-described configuration may further have the following configuration.

[0154] Regarding the heat insulation portion groove 140, the groove width shown by W in FIG. 35 108 is preferably 1500 μm or less, may be 1000 μm or less, and may be 700 μm or less. On the other hand, the width W 108is preferably 20 μm or more, may be 45 μm or more, and may be 60 μm or more. Width W 108 The range may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Also, width W 108 The range may be determined by combining any two of the plurality of upper limit candidate values, or by combining any two of the plurality of lower limit candidate values. Also, in FIG. 35, D 104 The depth of the groove shown is preferably 200 μm or less, may be 150 μm or less, and may be 100 μm or less. On the other hand, depth D 104 is preferably 5 μm or more, may be 10 μm or more, and may be 20 μm or more. Depth D 104 The range may be determined by a combination of any one of the plurality of upper limit candidate values and one of the plurality of lower limit candidate values. Also, depth D 104 The range may be determined by combining any two of the plurality of upper limit candidate values, or by combining any two of the plurality of lower limit candidate values.

[0155] <<Vapor flow path groove>> Next, the vapor flow path groove 142 will be described. The vapor flow path groove 142 is a part of the vapor flow path 4 (see FIGS. 19 and the like), which is the first flow path, where the vapor formed by the evaporation and vaporization of the working fluid passes through. FIGS. 28 and 29 show the shape of the vapor flow path groove 142 in plan view, and FIG. 30 shows the cross-sectional shape of the vapor flow path groove 142.

[0156] As can be seen from these figures, in this embodiment, the vapor flow path groove 142 is formed by a groove (slit) formed inside the annular shape of the outer peripheral liquid flow path portion 134 in the main body 131. Specifically, the vapor flow path groove 142 of this embodiment is formed between adjacent inner liquid flow path portions 138 and between the outer peripheral liquid flow path portion 134 and the inner liquid flow path portion 138, and is a groove extending in the direction (x direction) parallel to the long side of the rectangular shape of the main body 131 in plan view. And a plurality (four in this embodiment) of vapor flow path grooves 142 are arranged in the direction (y direction) parallel to the short side. The vapor flow path groove 142 of this embodiment is configured to communicate the first surface 130a and the second surface 130b side of the third sheet 130, that is, it is a slit-shaped groove and opens to the first surface 130a and the second surface 130b side. Therefore, as can be seen from FIG. 30, the third sheet 130 has a shape in which the outer peripheral liquid flow path portion 134, the inner liquid flow path portion 138, and the vapor flow path groove 142 are alternately repeated in the y direction.

[0157] The configuration of the vapor flow path groove 142 having such a configuration can be considered in the same way as the vapor flow path groove 42 described in Embodiment 1.

[0158] [[Vapor flow path communication groove]] The vapor flow path communication groove 44 is a groove that communicates a plurality of vapor flow path grooves 142, and can be considered in the same way as the vapor flow path communication groove 44 described in Embodiment 1 above, so the same reference numerals are given and the description is omitted.

[0159] [Structure of vapor chamber] Next, the structure when the first sheet 10, the second sheet, and the third sheet 130 are combined to form the vapor chamber 101 will be described. Through this description, the shape of the vapor chamber 101 and the arrangement, size, shape, etc. of each configuration that the first sheet 10, the second sheet, and the third sheet 130 should have will be further understood.

[0160] FIG. 38 shows a cross-sectional view of the vapor chamber 101 cut in the thickness direction along the y direction indicated by C in FIG. 26. 111 -C 111 FIG. 39 shows C in FIG. 26.112 -C 112 Fig. 3 shows a cross-sectional view of the vapor chamber 101 cut along the x direction shown by 112 in the thickness direction. In Fig. 40, the portion shown by C in Fig. 38 113 is shown enlarged, in Fig. 41, the portion of the outer peripheral liquid flow path portion 134 where the column 136a is provided, in Fig. 42, the portion shown by C in Fig. 38 114 is shown enlarged, and in Fig. 43, the portion of the inner liquid flow path portion 138 where the column 140a is provided. In the cross-sections shown in Figs. 38 to 43, the vapor flow path 4 and the condensate flow path 3 are separated by the convex portions 35a and 39a, but the convex portions 35a and 39a are each provided with a communication opening 35b and a communication opening 39b. Therefore, the vapor flow path 4 and the condensate flow path 3 communicate with each other through the communication opening 35b and the communication opening 39b.

[0161] As can be seen from Figs. 26, 27, and 38 to 42, the inner surface 10a of the first sheet 10 is overlapped on the first surface 130a side of the third sheet 130, and the inner surface 20a of the second sheet 20 is overlapped on the second surface 130b side of the third sheet 130 and is arranged and joined to form the vapor chamber 101. At this time, the main body 131 of the third sheet 130 overlaps with the main body 11 of the first sheet 10, and the main body 131 of the third sheet 130 overlaps with the main body 21 of the second sheet 20. The injection portion 32 of the third sheet 130 overlaps with the injection portion 12 of the first sheet 10, and the injection portion 32 of the third sheet 130 overlaps with the injection portion 22 of the second sheet 20.

[0162] With such a laminate of the first sheet 10, the second sheet 20, and the third sheet 130, each component provided in the main body 11, the main body 21, and the main body 131 is arranged as shown in Figs. 38 to 42. Specifically, it is as follows.

[0163] The outer peripheral joint surface 33a provided on the first surface 130a side of the third sheet 130 is arranged so as to overlap with the surface of the outer peripheral portion of the inner surface 10a of the first sheet 10, and the outer peripheral joint surface 33b provided on the second surface 30b side of the third sheet 30 is arranged so as to overlap with the surface of the outer peripheral portion of the inner surface 20a of the second sheet 20, and they are joined by joining means such as diffusion bonding or brazing. As a result, a hollow portion based on the shape of the third sheet 130 is formed between the first sheet 10 and the second sheet 20, and an operating fluid is sealed therein to form a sealed space 102.

[0164] The inner surface 10a of the first sheet 10 is arranged so as to overlap with the first surface 130a side of the outer peripheral liquid flow path portion 134 of the third sheet 130. Thereby, the opening of the liquid flow path groove 35 is blocked by the first sheet 10 and becomes a part of the hollow portion. This becomes a condensate flow path 3 which is a second flow path through which condensate, which is a state in which the operating fluid sealed in the hollow portion has condensed and liquefied, flows.

[0165] The inner surface 20a of the second sheet 20 is arranged so as to overlap with the second surface 30b side of the outer peripheral liquid flow path portion 134 of the third sheet 130. Thereby, the opening of the heat insulation portion groove 136 is blocked by the second sheet 20 and becomes the heat insulation portion 6. The heat insulation portion 6 is configured not to communicate with the condensate flow path 3 and the vapor flow path 4, and the heat conductivity here is made lower than that of the material adjacent to the heat insulation portion 6. Specifically, although not particularly limited, the heat insulation portion 6 may be evacuated, filled with air or other gases, or filled with a material having a low heat conductivity.

[0166] The inner surface 10a of the first sheet 10 is arranged so as to overlap with the first surface 130a side of the inner peripheral liquid flow path portion 138 of the third sheet 130. Thereby, the opening of the liquid flow path groove 39 is blocked by the first sheet 10 and becomes a part of the hollow portion. This becomes a condensate flow path 3 which is a second flow path through which condensate, which is a state in which the operating fluid sealed in the hollow portion has condensed and liquefied, flows.

[0167] The inner surface 20a of the second sheet 20 is disposed so as to overlap the second surface 130b side of the inner liquid flow path portion 138 of the third sheet 130. As a result, the opening of the heat insulation portion groove 140 is blocked by the second sheet 20 to form the heat insulation portion 6. The heat insulation portion 6 is configured not to communicate with the condensate flow path 3 and the vapor flow path 4, and here, the heat conductivity is made lower than that of the material adjacent to the heat insulation portion 6. Specifically, although not particularly limited, the heat insulation portion 6 may be evacuated, filled with air or other gas, or filled with a material having a low heat conductivity.

[0168] In this way, in the condensate flow path 3, by forming a narrow flow path surrounded by walls on all four sides in the cross section, the condensate is moved by a strong capillary force, enabling smooth circulation. That is, when considering a flow path assuming the flow of condensate, a higher capillary force can be obtained by the condensate flow path 3 compared to a so-called groove-type flow path in which one surface of the flow path is continuously open. Further, since the condensate flow path 3 is formed separately from the vapor flow path 4 which is the first flow path, the circulation of the working fluid can be made smooth.

[0169] On the other hand, on the opposite side of the condensate flow path 3 in the thickness direction (z direction) of the vapor chamber 101, a heat insulation portion with a reduced heat conductivity is provided. As a result, the transfer of heat to the working fluid is moderated, local temperature rise and local temperature drop are reduced, and thus the uniformity can be enhanced. More specifically, it is possible to suppress the blockage of the flow of the working fluid due to dry-out caused by rapid heating or condensate clogging due to condensation earlier than necessary, etc., and the heat transport capacity can be enhanced.

[0170] The shapes of the condensate flow path 3 and the heat insulation portion 6 can be considered based on the shapes and dimensions described for the third sheet 130 above.

[0171] The other parts will be described. As can be seen from FIG. 38, the opening of the steam flow path groove 142 is blocked by the first sheet 10 and the second sheet 20 to form a part of the hollow portion, which forms the flow path of the working fluid and becomes the steam flow path 4 that is the first flow path through which steam flows. The relationship between the flow path cross-sectional area of the condensate flow path 3 and the flow path cross-sectional area of the steam flow path 4 can be considered in the same way as the relationship between the flow path cross-sectional area of the condensate flow path 3 and the flow path cross-sectional area of the steam flow path 4 described in Form 1.

[0172] The shape of the steam flow path 4 can be considered based on the shape and dimensions described for the third sheet 130 above. In addition, in this form, since the introduction part 37 and the introduction part 41 are provided, the steam flow path 4 is configured to be in contact with the two introduction parts.

[0173] As can be seen from FIG. 39, the opening of the groove 44a of the steam flow path communication groove 44 of the third sheet 130 is blocked by the first sheet 10, and the opening of the groove 44b is blocked by the second sheet 20, respectively, to form a hollow portion in which a plurality of steam flow paths 4 communicate, which becomes the flow path for the working fluid.

[0174] The working fluid is enclosed in the sealed space 102 of the vapor chamber 101. The type of the working fluid is not particularly limited, and working fluids usually used in normal vapor chambers such as pure water, ethanol, methanol, acetone, and mixtures thereof can be used.

[0175] [Manufacture of Vapor Chamber] The vapor chamber as described above can be manufactured, for example, as follows. For the sheet having the outer peripheral shape of the third sheet 130, the liquid flow path groove 35, the heat insulation part groove 136, the liquid flow path groove 39, the heat insulation part groove 140, the steam flow path groove 142, and the grooves 44a and 44b are formed by half etching. However, for the steam flow path groove 142, it is performed so as to penetrate in the thickness direction by half etching from both the first surface 130a side and the second surface 130b side. By performing etching in this way, the shapes of the introduction part 37 and the introduction part 41 can also be formed.

[0176] Next, the first sheet 10 is overlapped on the first surface 130a side of the third sheet 130, and the second sheet 20 is overlapped on the second surface 130b side of the third sheet 130 and temporarily fixed. The method of temporary fixing is not particularly limited, and examples thereof include resistance welding, ultrasonic welding, and adhesion with an adhesive. After the temporary fixing, diffusion bonding is performed to permanently bond the first sheet 10, the second sheet 20, and the third sheet 130 to form a sheet for the vapor chamber. Note that, instead of diffusion bonding, brazing may be used for bonding. Here, "permanently bonding" is not strictly defined, and it means that the bonding is maintained to such an extent that the airtightness of the sealed space 102 can be maintained during the operation of the vapor chamber 101. By performing this bonding in a vacuum, the heat insulation part 6 can be evacuated. If it is performed in air or other gases, the heat insulation part 6 can be filled with a gas corresponding thereto. If the heat insulation part groove 136 is provided with the pillar 136a and the heat insulation part groove 140 is provided with the pillar 140a, during bonding, as well as during the subsequent evacuation of the hollow part and the injection of the working fluid, the collapse and swelling of the heat insulation part 6 can be suppressed. Also, when a solid material is placed in the heat insulation part 6, the material may be placed in the heat insulation part groove before bonding.

[0177] After bonding, evacuation is performed through the formed injection channel 5 to reduce the pressure in the hollow part. Then, the working fluid is injected into the depressurized hollow part through the injection channel 5 so that the working fluid enters the hollow part. Then, the injection channels 5 that overlap are closed by welding using melting or caulking to form a sealed space. Thereby, the working fluid is stably held inside the sealed space 102.

[0178] In the vapor chamber of this embodiment, since the internal liquid flow path part 138 functions as a support column, it is possible to suppress the sealed space from being crushed during bonding and decompression.

[0179] [Operation of the vapor chamber] Next, the operation of the vapor chamber 101 will be described. The arrangement of the vapor chamber 101 on the electronic device is as described in Embodiment 1 (FIGS. 1 and 19). Also, the concept of the movement of the working fluid and the diffusion of heat in the condensate flow path 3 and the vapor flow path 4 can be considered in the same way as described in Embodiment 1.

[0180] In this embodiment, since the heat insulating portion 6 is provided on the opposite side of the condensate flow path 3 in the thickness direction (z direction) of the vapor chamber 101, the transfer of heat to the working fluid is moderated, local temperature rise and local temperature drop are reduced, and thus the uniformity can be enhanced. That is, it is possible to suppress the flow of the working fluid from being inhibited due to dry-out caused by rapid heating or condensate blockage due to condensation earlier than necessary, and the heat transport capacity can be enhanced. Therefore, the heat insulating portion does not necessarily have to be arranged over the entire vapor chamber, and it may be arranged only at a site where local heat transfer is assumed. Examples of this include the site where the heat source (electronic component) is arranged, or conversely, the end portion of the vapor chamber separated from the heat source.

[0181] Also, in the form in which the introduction portions 37 and 41 are provided, a site surrounded by the introduction surfaces 37b and 41b and the first sheet 10 and the second sheet 20 is formed, and condensate is likely to accumulate here due to the action of capillary force. As a result, the introduction of the condensate into the condensate flow path 3 is performed more smoothly.

[0182] 2.2. Other Embodiments FIG. 44 shows an example in which the heat insulating portion groove 140 is provided in a part of the second surface 130b of the third sheet 130. This figure corresponds to FIG. 29. Thereby, the heat insulating portion 6 is also limited to the site where the heat insulating portion groove 140 is provided. For example, the heat insulating portion 6 can be provided at a portion close to the object to be cooled and a portion where condensation is desired to be suppressed, and the heat insulating portion 6 can be provided according to the thermal design, such as not providing the heat insulating portion 6 at a portion where rapid condensation is desired.

[0183] Figures 45 to 47 show examples in which a heat insulating portion 6 is also provided in the steam flow path 4. All of them are diagrams corresponding to Fig. 38. Fig. 45 shows an example in which a heat insulating portion 6 is provided in each of the condensate flow path 3 and the steam flow path 4. Fig. 46 shows an example in which the heat insulating portion 6 is formed as a heat insulating portion 6 communicating through the condensate flow path 3 and the steam flow path 4. And Fig. 47 shows an example in which the heat insulating portion 6 is provided only in the steam flow path 4.

[0184] 3. Embodiment 3 Although the introduction portions 37 and 39 have been described in Embodiments 1 and 2, the introduction portion will be described in detail in Embodiment 3. Therefore, since the configurations other than the introduction portion can be considered in the same manner as in Embodiments 1 and 2 described above, the description thereof will be omitted. Further, in Embodiment 1, the liquid flow path groove 40 is provided on the second surface 30b of the third sheet 30, and in Embodiment 2, the heat insulating portion groove 140 is provided on the second surface 130b of the third sheet 130. However, since it is not always necessary for these elements to be provided on the second surface of the third sheet, an example in which these elements are not provided on the second surface of the third sheet will be described here. However, it does not prevent the second surface of the third sheet from having the liquid flow path groove 40 or the heat insulating groove 140. In the following description, the reference numerals used in Embodiment 1 will be used for the elements other than the introduction portion.

[0185] 3.1. Embodiment 3a Figs. 48(a) and 48(b) are diagrams for explaining the inner liquid flow path portion 238, and are diagrams corresponding to Figs. 13(a) and 13(b). Here, the introduction portion 241 will be described by the inner liquid flow path portion 238, but the introduction portion provided in the outer liquid flow path portion can be considered in the same manner.

[0186] In this embodiment, an introduction portion 241 is provided in the inner liquid flow path portion 238. The introduction portion 241 is a portion formed at the boundary surface with the steam flow path groove 42 and is a portion protruding toward the steam flow path groove 42 side. Therefore, in this embodiment, the introduction portions 241 are arranged on both sides in the width direction (y direction) of the inner liquid flow path portion 238. In this embodiment, the introduction portion 241 is at a distance of T from the first surface 30a (the top of the convex portion 39a of the liquid flow path groove) in the thickness direction (z direction). 203It has the most prominent top 241a at the position of , and from the top 241a towards the liquid flow path groove 39, an arcuate introduction surface 241b that is concave towards the inner liquid flow path portion 238 in a cross-sectional view is provided. However, it does not necessarily have to be arcuate, and it may be a curved shape other than an arc that is concave towards the inner liquid flow path portion 238 in a cross-sectional view. Other exemplary forms of the introduction portion will be shown later, but any introduction portion has a surface (introduction surface) that has a portion protruding towards the vapor flow path groove 42 (vapor flow path) and has a surface that approaches the liquid flow path groove (condensate flow path) from the most prominent top thereof.

[0187] According to such an introduction portion 241, condensate is likely to collect on the introduction surface 241b, and the movement of the working fluid between the condensate flow path 3 and the vapor flow path 4 through the introduction portion 241 becomes smooth, and the heat transfer capacity can be enhanced.

[0188] Also, the surface of the introduction surface 241b is not particularly limited, but it may be a rough surface or a minute stepped surface. Thereby, the holding power of the condensate can be enhanced. The surface roughness (ISO 25178) of the introduction surface can be measured, for example, with a laser microscope (model number: VK-X250) manufactured by Keyence Corporation. And the arithmetic mean height Sa of this surface roughness is preferably 0.005 μm or more, more preferably 0.03 μm or more. Also, the maximum height Sz is preferably 0.05 μm or more, more preferably 0.3 μm or more.

[0189] The introduction portion 241 having the above-described configuration preferably further has the following configuration. In FIG. 48(a), W 205 The width of the inner liquid flow path portion 238 shown in (the size in the direction in which the inner liquid flow path portion 238 and the vapor flow path groove 42 are arranged, the maximum value) is preferably 3000 μm or less, may be 2000 μm or less, and may be 1500 μm or less. On the other hand, this width W 205 is preferably 100 μm or more, may be 200 μm or more, and may be 400 μm or more. This width W 205The range may be determined by a combination of any one of the plurality of candidate upper limit values and one of the plurality of candidate lower limit values. Also, the width W 205 The range may be determined by combining any two of the plurality of candidate upper limit values or by combining any two of the plurality of candidate lower limit values.

[0190] As shown by W in Fig. 48(a) 207 The protrusion amount (the distance from the end of the convex portion 39a to the top 241a) is preferably 1000 μm or less, may be 500 μm or less, or may be 300 μm or less. On the other hand, the protrusion amount W 207 is preferably 20 μm or more, may be 45 μm or more, or may be 60 μm or more. The range of the protrusion amount W 207 may be determined by a combination of any one of the plurality of candidate upper limit values and one of the plurality of candidate lower limit values. Also, the range of the protrusion amount W 207 may be determined by combining any two of the plurality of candidate upper limit values or by combining any two of the plurality of candidate lower limit values. Also, as shown by T in Fig. 48(a) 203 The thickness direction distance from the top 241a of the convex portion 39a to the top 241a of the introduction portion 241 is, when the thickness of the inner liquid flow path portion 238 is T 204 is preferably 0.05 or more, may be 0.15 or more, or may be 0.3 or more when divided by T 203 by T 204 . On the other hand, the value obtained by dividing T 203 by T 204 may be 1.0 or less, may be 0.8 or less, or may be 0.6 or less. The range of the value obtained by dividing the said T 203 by T 204 may be determined by a combination of any one of the plurality of candidate upper limit values and one of the plurality of candidate lower limit values. Also, the range of the value obtained by dividing T 203 by T 204 may be determined by combining any two of the plurality of candidate upper limit values or by combining any two of the plurality of candidate lower limit values. In this embodiment, the value is 0.5, and the top portion 241a is disposed at a position that is the center in the thickness direction of the inner liquid flow path portion 238.

[0191] Further, as shown in FIG. 48(a), when the width of the liquid flow path groove 39 closest to the introduction portion 241 is W 209 and the depth of the liquid flow path groove 39 closest to the introduction portion 241 is D 201 and, of the protruding amount of the introduction portion 241, the protruding amount on the side of the surface 30b (the surface on the side where the liquid flow path groove 39 is not provided) is W 210 it is preferably in the following relationship. D 201 × (W 209 / 2) < T 203 × W 207 < (T 204 - T 203 ) × W 210 Thereby, the condensed liquid working fluid is easily recovered in the condensate flow path 3, and the movement of the liquid working fluid between the vapor flow path 4 and the condensate flow path 3 is facilitated. Further, thereby, the liquid working fluid easily evaporates in the vapor flow path 4.

[0192] Next, a description will be given of the case where the first sheet 10, the second sheet, and the third sheet 30 are combined to form the vapor chamber 1. FIGS. 49(a) and 49(b) show diagrams corresponding to FIGS. 18(a) and 18(b). In the cross section shown in FIG. 49(a), the vapor flow path 4 and the vapor flow path 3 are separated by the convex portion 39a, but the convex portion 39a is provided with the communication opening 39b. Therefore, according to the cross section in which the communication opening 39b is adjacent to the vapor flow path 4 as shown in FIG. 49(b), the vapor flow path 4 and the vapor flow path 3 communicate with each other through the communication opening 39b.

[0193] As can be seen from FIGS. 49(a) and 49(b), the inner surface 10a of the first sheet 10 is overlapped on the first surface 30a side of the third sheet 30, and the inner surface 20a of the second sheet 20 is overlapped on the second surface 30b side of the third sheet 30, and they are arranged and joined to form the vapor chamber 1.

[0194] Due to the provision of the introduction part 241, it is arranged between the condensate flow path 3 and the vapor flow path 4 and is equipped with the introduction part 241 protruding toward the vapor flow path 4 side. In this embodiment, the introduction part 241 has a top part 241a that protrudes most toward the vapor flow path 4 side in the thickness direction (z direction), and an introduction surface 241b that is arc-shaped in cross section is provided from the top part 241a toward the side where the condensate flow path 3 is provided. That is, the introduction part is arranged between the condensate flow path 3 and the vapor flow path 4, protrudes toward the vapor flow path 4 side, and has a surface (introduction surface) including a surface that approaches the condensate flow path 3 from the most protruding part (top part).

[0195] The working fluid that has been condensed by having its heat taken away while moving through the vapor flow path 4 adheres to the wall surface of the vapor flow path 4. On the other hand, since vapor continuously flows through the vapor flow path 4, the condensate moves to the condensate flow path 3 as if it is pushed by the vapor as shown by the arrow C in FIGS. 49(a) and 49(b). 211 The condensate flow path 3 is provided with communication openings 39b, so the condensate is distributed to the plurality of condensate flow paths 3 through these communication openings. At this time, since the introduction part 241 is provided on the inner surface of the vapor flow path 4, a part sandwiched between the introduction surface 241b and the first sheet 10 is generated, and condensate tends to accumulate here due to the action of capillary force. As a result, the introduction of the condensate into the condensate flow path 3 can be performed more smoothly, and the heat transport amount can be increased.

[0196] Here, it is preferable that the vapor flow path 4, the introduction part 241, and the condensate flow path 3 have the following relationship. A diagram for explanation is shown in FIG. 50. In FIG. 50, some of the reference numerals are omitted for ease of viewing, but FIG. 49(a) can be referred to. In the same cross section as FIG. 49(a), a rectangle with the distance between the opposing top parts 241a in the vapor flow path 4 as the horizontal side and the size in the thickness direction of the vapor flow path 4 as the vertical side is defined as region A, and its area is A A is defined as. In the same cross section as FIG. 49(a), a region surrounded by the introduction surface 241b, region A, the convex part 39a, and the first sheet 10 in the vapor flow path 4 is defined as region B, and its area is A B is defined as. In the same cross-section as FIG. 49(a), the region of the condensate flow path 3 closest to region B is defined as region C, and its area is A C Let it be so. These A A 、A B 、A C Preferably have the following relationship. A A >A B >A C By having such a relationship, it becomes easier to draw the working fluid condensed from the vapor flow path 4 into the condensate flow path 3, and it is possible to suppress the outflow of the liquid that has rapidly vaporized from the condensate flow path 3 to the vapor flow path 4.

[0197] 3.2. Forms 3b to 3h In the figures shown below, FIGS. are shown that illustrate Forms 3b to 3h, which are other morphological examples, focusing on the shape of the introduction part. All are figures corresponding to FIGS. 49(a) and 49(b). Note that these forms of the introduction part can also be applied to the outer peripheral liquid flow path part. For convenience, in any of the morphological examples, reference numeral 238 represents the inner liquid flow path part, reference numeral 241 represents the introduction part, reference numeral 241a represents the top part, and reference numeral 241b represents the introduction surface.

[0198] In Form 3b of FIGS. 51(a) and 51(b), the top part 241a is arranged closer to the condensate flow path 3 in the thickness direction compared to the top part 41a of Form 3a in FIGS. 49(a) and 49(b). Specifically, the value obtained by dividing T shown in FIG. 48 by T 203 is in the range of 0.2 or more and 0.4 or less. 204 According to this form, since the space sandwiched between the introduction surface 141b and the first sheet 10 is small, the capillary force acts strongly and easily, and the above effects become more prominent. In Form 3c of FIGS. 52(a) and 52(b), the introduction surface 241b extending from the top part 241a is linear in a cross-sectional view. The introduction surfaces 241b of Forms 3a and 3b described above were both concave arc-shaped on the inner liquid flow path part 238 side, but in Form 3c, the introduction surface 241b is linear in cross-section.

[0199] Even in such a form, the above effects can be achieved.

[0200] In the form 3d of FIGS. 53(a) and 53(b), the top portion 241a is planar, and the introduction surface 241b has a surface extending parallel (y direction) to the direction in which the plurality of condensate flow paths 3 and vapor flow paths 4 are arranged. Even in such a form, the above effects can be achieved.

[0201] In the form 3e of FIGS. 54(a) and 54(b), the introduction surface 241b extending from the top portion 241a is an arc shape convex toward the vapor flow path 4 in a cross-sectional view. However, it is not necessary to be an arc shape, and it may be a curved shape other than an arc convex toward the vapor flow path 4 in a cross-sectional view. Even in such a form, the above effects can be achieved. In this form, as the introduction surface 241b approaches the condensate flow path 3, a relatively large number of portions with a narrow interval from the first sheet 10 can be formed, and efficient utilization of capillary force can be expected.

[0202] In the form 3f of FIGS. 55(a) and 55(b), an example is shown in which the top portion 241a is provided so as to be separated to the surface on the side opposite to the condensate flow path 3 side of the vapor flow path 4. Even in such a form, the introduction surface 241b can be formed and the above effects can be achieved. However, from the viewpoint of utilizing stronger capillary force by narrowing the space between the introduction surface and the first surface 10a, as in each of the above-described exemplary forms, the top portion is preferably disposed on either side surface that does not coincide with the inner surface facing in the thickness direction among the vapor flow paths in the thickness direction.

[0203] In the form 3g of FIGS. 56(a) and 56(b), the condensate flow path 3 is formed in both thickness directions of the inner liquid flow path portion 238 (that is, in this respect, it is the same as the form 1). In this example, the introduction portion 241 can form introduction surfaces 241b from its top portion 241a toward both of the condensate flow paths 3, and the above effects can be achieved for each of the condensate flow paths 3 existing in both thickness directions.

[0204] In Embodiment 3h of FIGS. 57(a) and 57(b), the condensate flow path 3 is formed at the center in the thickness direction of the inner liquid flow path portion 238. In this example, the vapor chamber consists of two sheets. In this case, the first sheet 210 has a configuration that includes a part of the above-described first sheet 10 and the third sheet 30, and the second sheet 220 has a configuration that includes a part of the above-described second sheet 20 and the third sheet 30. By combining the two, a sealed space of the vapor chamber is formed. And in this Embodiment 3h, the introduction surface 241b extends from the top 241a of the introduction portion 241 in a plane parallel to the direction (y direction) in which the plurality of condensate flow paths 3 and vapor flow paths 4 are arranged. Even in such a form, the above effects can be achieved.

[0205] Note that this embodiment is an example in which the thickness direction position (z direction position) of the top 241a and the condensate flow path 3 is the same, and in the above-described embodiments, the thickness direction position (z direction position) of the top and the condensate flow path is different. Although either can be applied as needed, it tends to be possible to hold and introduce more condensate when the thickness direction position (z direction position) of the top and the condensate flow path is different.

[0206] 4. Embodiment 4 In the vapor chamber, in a temperature environment lower than the freezing point of the enclosed working fluid, the working fluid may freeze. When it expands due to freezing like pure water, etc., it is conceivable that the vapor chamber may be deformed due to the volume expansion of the working fluid in the vapor flow path portion. When there are such problems, it is preferable to have a form that can suppress deformation and exhibit more stable performance even when the working fluid freezes and expands. Therefore, in Embodiment 4, a vapor chamber having a structure for this purpose will be described.

[0207] In Form 4, it is different from the first sheet 10 and the second sheet 20 in Forms 1 to 3. Therefore, since the above-described modes in Forms 1 to 3 can be applied to the third sheet, the description thereof is omitted here. For the sake of convenience, an example in which the third sheet 30 of Form 1 is applied will be described here, but it is not limited thereto. Therefore, the arrangement on the electronic device, the operation of the working fluid, and the concept of heat diffusion thereby are as described above, and the description thereof is omitted.

[0208] 4.1. Form 4a [Form] FIG. 58 shows a cross-section of the vapor chamber 301, and FIG. 58 corresponds to FIG. 15. As can be seen from FIG. 58, the first sheet 310 includes an inner sheet 311 and a reinforcing sheet 312, and the second sheet 320 includes an inner sheet 321 and a reinforcing sheet.

[0209] The inner sheet 311 is a sheet disposed in contact with the first surface 30a of the third sheet 30 and constitutes the inner surface 10a. Similarly, the inner sheet 321 is a sheet disposed in contact with the second surface 30b of the third sheet 30 and constitutes the inner surface 20a. The reinforcing sheet 312 is a sheet disposed on the side opposite to the third sheet 30 side of the inner sheet 311 and constitutes the outer surface 10b. Similarly, the reinforcing sheet 322 is a sheet disposed on the side opposite to the third sheet 30 side of the inner sheet 321 and constitutes the outer surface 10b.

[0210] The inner sheet 311 and the reinforcing sheet 312 may be configured as a clad material. The clad material means a laminated material in which a plurality of types of sheets are joined to each other. For example, the inner sheet 311 and the reinforcing sheet 312 may be produced as a clad material by plating one sheet with the other sheet. In this case, an adhesion layer (strike plating layer, seed layer, etc.) (not shown) for improving the adhesion between the two sheets may be interposed therebetween. Further, the two sheets may be produced as a clad material by diffusion bonding. Similarly, the inner sheet 321 and the reinforcing sheet 322 may be configured as a clad material. The clad material means a laminated material in which a plurality of types of sheets are joined to each other. For example, the inner sheet 321 and the reinforcing sheet 322 may be produced as a clad material by plating one sheet with the other sheet. In this case, an adhesion layer (such as a strike plating layer or a seed layer), not shown, for improving the adhesion between the two sheets may be interposed therebetween. Furthermore, the two sheets may be produced as a clad material by diffusion bonding.

[0211] The material constituting the inner sheet 311 and the inner sheet 321 is not particularly limited as long as it has good thermal conductivity. For example, it may contain copper or a copper alloy. In this case, the thermal conductivity of each sheet can be increased. Therefore, the heat dissipation efficiency of the vapor chamber 301 can be increased. Also, when pure water is used as the working fluid, corrosion can be prevented. Note that other metal materials such as aluminum and titanium, and other metal alloy materials such as stainless steel can also be used as long as the desired heat dissipation efficiency can be obtained and corrosion can be prevented.

[0212] The reinforcing sheet 312 is made of a material with higher yield strength than the inner sheet 311, and the reinforcing sheet 322 is made of a material with higher yield strength than the inner sheet 321. Here, the yield strength is defined as the stress at which the permanent strain at unloading becomes 0.2%. The specific materials of the reinforcing sheet 312 and the reinforcing sheet 322 are not particularly limited, but it is preferable that they are metal materials with good thermal conductivity and have the desired mechanical strength. For example, materials containing copper alloy, iron alloy, nickel, nickel alloy, titanium, titanium alloy, or aluminum alloy can be mentioned. Examples of the iron alloy include stainless steel, Invar (iron alloy containing nickel), and Kovar (iron alloy containing cobalt).

[0213] The thickness of the inner sheets 311 and 312 can be, for example, 0.2 μm or more and 100 μm or less. By setting this thickness to 0.2 μm or more, it is possible to prevent pinholes from being formed in the inner sheets 311 and 312, and to prevent impurities contained in the materials constituting the reinforcing sheets 312 and 322 from depositing on the third sheet 30 side through the pinholes. On the other hand, by setting it to 100 μm or less, it is possible to suppress an increase in the thickness of the vapor chamber 301. The thickness of the inner sheet is more preferably 0.25 μm or more and 10 μm or less, and even more preferably 0.45 μm or more and 5 μm or less.

[0214] Also, the thickness of the reinforcing sheets 312 and 322 may be greater than the thickness of the inner sheets 311 and 321 in order to enhance the reinforcing function. However, from the viewpoint of enhancing the reinforcing function, it is preferable that the reinforcing sheet 321 is thicker than the inner sheet 311. More specifically, the thickness of the reinforcing sheet is preferably 5 times or more and 30 times or less the thickness of the inner sheet, and more preferably 5 times or more and 20 times or less. The specific thickness of the reinforcing sheets 312 and 322 is not particularly limited, but is, for example, 3 μm or more and 100 μm or less. By setting this thickness to 3 μm or more, effective reinforcement can be achieved. On the other hand, by setting it to 100 μm or less, it is possible to suppress an increase in the thickness of the vapor chamber 301. More preferably, it is 5 μm or more and 50 μm or less, and even more preferably 9 μm or more and 25 μm or less.

[0215] Also, the thickness of the first sheet 310 and the second sheet 320 is 0.1 mm or less, preferably 0.05 mm or less, and more preferably 0.02 mm or less. This enables the production of a thin (e.g., 0.4 mm or less) vapor chamber in which freeze expansion is less likely to occur. On the other hand, the thickness of the first sheet 310 and the second sheet 320 is, for example, 0.01 mm or more. This can suppress deformation of the inner sheets 311 and 321 due to freeze expansion of the working fluid in the vapor flow path 4.

[0216] In addition, in this embodiment, both the first sheet 310 and the second sheet 320 include both an inner sheet and a reinforcing sheet. However, this is not limited thereto, and if not necessary, a form in which a reinforcing sheet is provided only on either the first sheet or the second sheet may be sufficient.

[0217] Furthermore, a layer of the same material and thickness as the inner sheet may be laminated on at least one of the reinforcing sheet 312 of the first sheet 310 and the reinforcing sheet 322 of the second sheet 320. According to this, warpage can be suppressed in the sheet on which the layer is laminated.

[0218] [Manufacturing Method] Next, a method for manufacturing the vapor chamber 301 having such a configuration will be described with reference to FIGS. 59 to 64.

[0219] First, as shown in FIG. 59, as a preparation step, a flat metal material sheet M including a first surface Ma and a second surface Mb is prepared.

[0220] Subsequently, as shown in FIG. 60, as a resist formation step, a resist film 340 is formed on the first surface Ma of the metal material sheet M, and a resist film 341 is formed on the second surface Mb. Before forming the resist film 340 and the resist film 341, the first surface Ma and the second surface Mb of the metal material sheet M may be subjected to an acid degreasing treatment as a pretreatment.

[0221] Next, as shown in FIG. 61, as a patterning step, the resist film 340 and the resist film 341 are patterned by photolithography technology. Patterning of the resist film 340 forms openings corresponding to the liquid flow path groove 39, the communication opening 39b, and the vapor flow path groove 42 of the inner liquid flow path 38. At this time, the openings corresponding to the liquid flow path groove 39 and the communication opening 39b can be formed to be smaller than the widths of these liquid flow path groove 39 and communication opening 39b. On the other hand, the opening corresponding to the vapor flow path groove 42 can be formed to have the same width as the width of the vapor flow path groove 42 on the first surface 30a. On one hand, for patterning the resist film 341, openings corresponding to the liquid flow path groove 40, the communication opening 40b, and the vapor flow path groove 42 of the inner liquid flow path 38 are formed. At this time, the openings corresponding to the liquid flow path groove 40 and the communication opening 40b can be formed to be smaller than the widths of these liquid flow path groove 40 and communication opening 40b. On the other hand, the opening corresponding to the vapor flow path groove 42 can be formed to have the same width as the width of the vapor flow path groove 42 on the second surface 30b.

[0222] Subsequently, as shown in FIG. 62, as an etching process, the first surface 30a and the second surface 30b of the metal material sheet M are etched. As a result, in the metal material sheet M, the portions corresponding to the openings where the resist films 340 and 341 are formed are etched, and the liquid flow path groove 39, the communication opening 39b, the liquid flow path portion 40, the communication opening 40b, and the vapor flow path groove 42 are formed. Note that, for example, an iron chloride-based etching solution such as an aqueous solution of ferric chloride or a copper chloride-based etching solution such as an aqueous solution of copper chloride can be used as the etching solution.

[0223] Here, as described above, among the resist films 340 and 341, if the openings corresponding to the liquid flow path groove 39, the communication opening 39b, the liquid flow path groove 40, and the communication opening 40b are formed with a width smaller than the groove width, the amount of the etching solution entering the opening is reduced, and the etching rate in this portion decreases. Therefore, the depths of these liquid flow path groove 39, communication opening 39b, liquid flow path groove 40, and communication opening 40b can be made shallower. In contrast, by forming the openings of the resist films 340 and 341 corresponding to the vapor flow path groove 42 to be the same as the width of the vapor flow path groove 42 on the first surface 30a and the second surface 30b, the amount of the etching solution entering the opening is ensured, and the etching depth for forming the vapor flow path groove 42 can be ensured (as a result, the vapor flow path groove 42 penetrates in the thickness direction).

[0224] Also, in order to form a portion that does not penetrate the groove in the thickness direction, such as the connecting portion 44c shown in FIG. 6 and other means for holding the inner liquid flow path portion 38, for that portion, the depth can be suppressed by adjusting the width of the resist film, or an opening can be provided only in one of the resist films disposed on both surfaces of the metal material sheet M.

[0225] After the etching process, as shown in FIG. 63, as a resist removal process, the resist film 340 and the resist film 341 are removed.

[0226] In this way, the third sheet 30 can be obtained.

[0227] As a preparation step of the first sheet 310, a sheet in which a reinforcing sheet 312 is laminated on the inner sheet 311, and As a preparation step of the second sheet 320, a sheet in which a reinforcing sheet 322 is laminated on the inner sheet 321 is prepared. The method of each preparation step is not particularly limited, but those manufactured as clad materials can be used. As another method, plating may be performed on the reinforcing sheets 311 and 322 formed from the rolled material to form the inner sheets 311 and 312. In this case, an adhesion layer for improving the joinability between the reinforcing sheets 312 and 322 and the inner sheets 311 and 321 may be interposed therebetween. Examples of the adhesion layer include a strike plating layer and a seed layer. For example, when the reinforcing sheets 312 and 322 are formed of stainless steel and the inner sheets 311 and 321 are formed of copper, a strike plating layer containing a material such as nickel or copper may be interposed, or a seed layer containing a material such as titanium or molybdenum may be interposed by performing sputtering. The thickness of the strike plating layer and the seed layer is, for example, in the range of 10 nm or more and 1000 nm or less. Alternatively, the inner sheets 311 and 321 may be formed from the rolled material, and the reinforcing sheets 312 and 322 may be formed by plating. Further, either one of the inner sheets 311 and 321 and the reinforcing sheets 312 and 322 may be formed by plating, and the other may be laminated and formed by further plating.

[0228] After preparing the third sheet 30, the first sheet 310, and the second sheet 320, as a temporary fixing step, they are temporarily fixed in a laminated state. The method of fixing for temporary fixing is not particularly limited, but for example, it can be performed by resistance welding. In this case, spot resistance welding may be performed using an electrode bar (not shown). Laser welding may be performed instead of resistance welding.

[0229] After the temporary fixing process, as shown in FIG. 64, as the joining process, the first sheet 310, the second sheet 320, and the third sheet 30 are permanently joined by diffusion bonding. Diffusion bonding is a method in which the first sheet 310 to be joined and the third sheet 30 are brought into close contact with each other, and the third sheet 30 and the second sheet 320 are brought into close contact with each other, and pressure is applied and heating is performed in the stacking direction in a controlled atmosphere such as in a vacuum or an inert gas, and joining is performed by utilizing the diffusion of atoms generated on the joining surface. Diffusion bonding heats the material constituting each sheet to a temperature close to the melting point, but since it is lower than the melting point, it is possible to avoid each sheet melting and deforming.

[0230] After the joining process, as the encapsulation process, the working fluid is encapsulated in the hollow portion from the injection portion. After the injection of the working fluid, the injection flow path is sealed. For example, the injection portion may be irradiated with a laser to partially melt the injection portion to seal the injection flow path. As a result, the space in which the working fluid is encapsulated is blocked from the outside. Note that, for sealing, the injection portion may be caulked (it may be pressed to cause plastic deformation), or brazed.

[0231] In this way, the vapor chamber 301 is obtained. In this example, each sheet is laminated after plating on the first sheet and the second sheet, but the present invention is not limited to this, and plating may be performed after laminating each sheet. According to this, a plated layer is also formed on the side surface.

[0232] [Operation of the vapor chamber] The operation process regarding the cooling of the heat source in the vapor chamber 301 is the same as the form described so far, so the description is omitted here. On the other hand, an electronic device equipped with the vapor chamber 301 may be placed in a temperature environment lower than the freezing point of the working fluid. In this case, the working fluid freezes and expands depending on the type of the working fluid. For example, when the working fluid is pure water, it can freeze and expand in an environment below the freezing point. Due to this expansion, a force in the direction of expanding the vapor chamber 301 in the thickness direction may be applied to the portion where the working fluid is accumulated.

[0233] On the other hand, in the vapor chamber 301, a reinforcing sheet 312 is provided on the first sheet 310, and a reinforcing sheet 322 is provided on the second sheet 320. Since the first sheet 310 and the second sheet 320 are each reinforced, it is possible to suppress deformation even when receiving the force due to the freezing expansion of the working fluid. Therefore, it is possible to suppress a decrease in the flatness of the contact surface with the heat source at the portion receiving heat from the heat source and the contact surface with a member (for example, a housing) at the portion releasing heat to the outside, and to suppress the formation of a gap. In this case, it is possible to suppress the inhibition of heat conduction from the heat source to the vapor chamber 301 and heat conduction from the vapor chamber 301 to the outside.

[0234] Further, if the thickness of the reinforcing sheet 312 is made thicker than the thickness of the inner sheet 311, and the thickness of the reinforcing sheet 322 is made thicker than the thickness of the inner sheet 321, the inner sheets 311 and 321 can be further reinforced by the reinforcing sheets 312 and 322, and the deformation of the vapor chamber 301 can be further suppressed.

[0235] 4.2. Embodiment 4b Next, Embodiment 4b will be described. FIGS. 65 and 66 show diagrams for explaining the vapor chamber 301' and the vapor chamber 301", respectively. Both are cross-sectional views corresponding to FIG. 64.

[0236] In the vapor chamber 301' shown in FIG. 65, the third sheet 30 is not arranged, and the first sheet 310' and the second sheet 320' are directly laminated. That is, it is configured by overlapping and joining the inner sheet 311' of the first sheet 310' and the inner sheet 321' of the second sheet 320'. However, in this embodiment, grooves are formed on the overlapping surfaces of the inner sheet 311' and the inner sheet 321', thereby forming the condensate flow path 3 and the vapor flow path 4. The concept of the forms of the condensate flow path 3 and the vapor flow path 4 is the same as described above. Even in such a form, since the reinforcing sheets 312 and 322 are provided, the same effects as described above are achieved.

[0237] The vapor chamber 301” shown in FIG. 66 also does not have the third sheet 30 disposed, and the first sheet 310” and the second sheet 320” are directly laminated. That is, it is configured by overlapping and joining the inner sheet 311” of the first sheet 310” and the inner sheet 321” of the second sheet 320”. In this embodiment, it is not the form in which the condensate flow path 3 is provided between adjacent vapor flow paths 4, but an example in which the condensate flow path 3 and the vapor flow path 4 are provided in the same flow path. Therefore, in this embodiment, the capillary structure member 339 is disposed in the same flow path as the flow path that becomes the vapor flow path 4. This capillary structure member 339 is configured as a capillary structure (wick) through which the liquefied working fluid flows. The capillary structure member 339 can be configured by, for example, a metal mesh, metal powder, metal twisted wire, or the like. Even in such a form, since the reinforcing sheets 312 and 322 are provided, the same effects as described above are achieved.

[0238] 5. Embodiment 5 The vapor chamber 401 of Embodiment 5 is an example in which the first sheet 410 and the second sheet 420 are applied instead of the first sheet 310 and the second sheet 320 provided in the vapor chamber 301 described in Embodiment 4. Further, this first sheet 410 is different from the first sheet 310 in that a barrier sheet 413 is disposed between the inner sheet 311 and the reinforcing sheet 312 described for the first sheet 310. Also, the second sheet 420 is different from the second sheet 320 in that a barrier sheet 423 is disposed between the inner sheet 321 and the reinforcing sheet 322 described for the first sheet 320. Therefore, except for the barrier sheets 413 and 423, it can be considered in the same way as the vapor chamber 301 of Embodiment 4, and thus the barrier sheets 413 and 423 will be described here.

[0239] The barrier materials constituting the barrier sheets 413 and 423 are not particularly limited as long as they can prevent the metal elements constituting the reinforcing sheets 312 and 322 from permeating toward the inner sheets 311 and 321. Such barrier materials may contain, for example, at least one of tungsten (W), titanium (Ti), tantalum (Ta), and molybdenum (Mo). The barrier material may be composed of only any one of tungsten, titanium, tantalum, and molybdenum. In this case, the barrier sheets 413 and 423 are formed as single-phase films. Alternatively, the barrier material may be composed of a combination of any two or more of tungsten, titanium, tantalum, and molybdenum. In this case, the barrier sheets 413 and 423 are formed as alloy films. Examples of such alloy films include alloy films of tungsten and titanium. Further, the barrier material may be a combination of the above-described four metal elements and other metal elements. Examples of alloy films in this case include alloy films of nickel and tungsten, etc.

[0240] The thickness of the barrier sheets 413 and 423 is arbitrary as long as the barrier function can be exhibited. The thickness of the barrier sheets 413 and 423 is, for example, in the range of 10 nm or more and 1000 nm or less. By setting the thickness of the barrier sheets 413 and 423 to 10 nm or more, it is possible to effectively prevent the metal elements constituting the reinforcing sheets 312 and 322 from permeating. On the other hand, by setting it to 1000 nm or less, it can be easily manufactured by sputtering treatment, and an increase in the thickness of the vapor chamber 401 can be suppressed. Furthermore, by setting it to 1000 nm or less, inhibition of heat conduction can be suppressed. From the viewpoint of more effectively exhibiting the barrier function, the thickness of the barrier sheet is preferably 100 nm or more.

[0241] Here, a method for checking the components of the barrier sheets 413 and 423 will be described. First, the presence or absence of the barrier sheets 413 and 423 can be confirmed by an image obtained by imaging a cross-section obtained by cutting the vapor chamber 401 at an arbitrary position with a SEM (scanning electron microscope). The components of the barrier sheets 413 and 423 can be analyzed, for example, by slightly scraping the lower surface of the vapor chamber 401, analyzing the scraped components by energy dispersive X-ray analysis (EDX), and further scraping and analyzing the components. By repeating the component analysis in this way, the components of the barrier sheets 413 and 423 can be confirmed.

[0242] Also, an adhesion layer for improving the adhesion between the barrier sheets 413 and 423 and the inner sheets 311 and 321 may be further formed. When the adhesion layer is formed, first, the adhesion layer is formed on the surface of the barrier sheets 413 and 423, and then the inner sheets 311 and 321 are formed on the surface of the adhesion layer. Examples of the adhesion layer include a strike plating layer and a seed layer. For example, when the barrier sheets 413 and 423 are formed of a material containing molybdenum and the inner sheets 311 and 321 are formed of copper, a seed layer containing a copper material may be interposed by performing a sputtering process using a sputtering target material containing copper. The thickness of the strike plating layer and the seed layer can be, for example, in the range of 50 nm or more and 500 nm or less. Alternatively, the cover sheets 413 and 423 may be formed from rolled materials, and the reinforcing sheets 312 and 322 may be formed by plating. Further, either one of the cover sheets 413 and 423 and the reinforcing sheets 312 and 322 may be formed by plating, and the other may be laminated by further plating.

[0243] According to such a vapor chamber 401, in addition to the same effects as the vapor chamber 301 described in Form 4, it is possible to suppress the diffusion of the metal material forming the reinforcing sheet into the inner sheet.

[0244] 6. Form 6 In Form 6, the shape of the liquid flow path groove of the third sheet is different from that of the vapor chambers of Forms 1 to 5 described so far. Since other parts can be considered in the same way as those in Forms 1 to 5, the inner liquid flow path part will be described here with attention focused on it, and the description of other parts will be omitted. However, the same shape can also be applied to the outer peripheral liquid flow path part. For the sake of convenience, parts common to Forms 1 to 5 are labeled with the reference numerals of Form 1, but the forms of Forms 2 to 5 can also be applied to the common parts.

[0245] 6.1. Form 6a FIG. 68 is a view of the inner liquid flow path part 538 of the vapor chamber 501 of this form as seen from the z direction, and is a view from the same perspective as FIG. 14. As can be seen from FIG. 68, the inner liquid flow path part 538 has a liquid flow path groove 551 extending in the x direction, and liquid flow path convex parts 552 which are a pair of convex parts adjacent to each other via the liquid flow path groove 551. The liquid flow path groove 551 is mainly configured to transport a liquid working fluid.

[0246] The pair of liquid flow path convex parts 552 is composed of a first liquid flow path convex part 552A arranged on one side with respect to the liquid flow path groove 551 (the y direction side in the figure), and a second liquid flow path convex part 552B arranged on the side opposite to the one side with respect to the liquid flow path groove 551 (the side opposite to the y direction in the figure). A plurality of the first liquid flow path convex parts 552A are arranged in the first direction (the x direction in the figure) to form a first liquid flow path convex part row 553A. Similarly, a plurality of the second liquid flow path convex parts 552B are arranged in the first direction (the x direction in the figure) to form a second liquid flow path convex part row 553B.

[0247] In addition, first connection grooves 554A are respectively formed between the plurality of first liquid flow path convex parts 552A arranged in the first direction (the x direction in the figure). Similarly, second connection grooves 554B are respectively formed between the plurality of second liquid flow path convex parts 552B arranged in the first direction (the x direction in the figure). Each of the first connection grooves 554A and each of the second connection grooves 554B are connected to the liquid flow path groove 551.

[0248] The working fluid that has lost heat from the vapor state and condensed into a liquid state on the surface of the vapor flow path groove 42 (vapor flow path 4) enters the first connection groove 554A and the second connection groove 554B from the surface of the vapor flow path groove 42 (vapor flow path 4) by capillary action, and further enters the liquid flow path groove 551 (condensate flow path 3) by capillary action.

[0249] In the example shown in FIG. 68, the plurality of first liquid flow path convex portions 552A that constitute the first liquid flow path convex portion row 553A are arranged in the first direction (x direction) at a constant pitch P 501 Similarly, the plurality of second liquid flow path convex portions 552B that constitute the second liquid flow path convex portion row 553B are also arranged in the first direction (x direction) at a constant pitch P 501 in the first direction (x direction).

[0250] By setting the pitch to be constant in this way, the design of the first liquid flow path convex portion row 553A and the second liquid flow path convex portion row 553B does not need to be complicated. Also, it is expected to equalize the actions of each pair of liquid flow path convex portions 552. For example, it is expected to equalize the ease of entry of the liquid working fluid from each of the plurality of first connection grooves 554A and the plurality of second connection grooves 554B into the liquid flow path groove 551. However, the plurality of first liquid flow path convex portions 552A and the plurality of second liquid flow path convex portions 552B do not necessarily have to be arranged at a constant pitch.

[0251] In the example shown in FIG. 68, the first liquid flow path convex portion 552A that constitutes a pair of liquid flow path convex portions 552 and the second liquid flow path convex portion 552B adjacent via the liquid flow path groove 551 are formed symmetrically with respect to the liquid flow path groove 551.

[0252] By making it symmetric in this way, the design of the first liquid flow path convex portion row 553A and the second liquid flow path convex portion row 553B does not need to be complicated. Also, it is expected to equalize the actions of each pair of liquid flow path convex portions 552. For example, it is expected to equalize the ease of entry of the liquid working fluid from each of the plurality of first connection grooves 554A and the plurality of second connection grooves 554B into the liquid flow path groove 551.

[0253] However, in this embodiment, the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B adjacent via the liquid flow path groove 551 do not have to be formed symmetrically with respect to the liquid flow path groove 551.

[0254] The first liquid flow path convex portion 552A extends in a direction inclined with respect to the first direction (x direction in the figure) so as to advance in the first direction while advancing from one side (y direction side in the figure) with respect to the liquid flow path groove 551 toward the liquid flow path groove 551. The second liquid flow path convex portion 552B extends in a direction inclined with respect to the first direction so as to advance in the first direction while advancing from the side opposite to the one side with respect to the liquid flow path groove 551 (the side opposite to the y direction in the figure) toward the liquid flow path groove 551. Further, the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B constituting the pair of liquid flow path convex portions 552 is smaller on the first direction side than on the side opposite to the first direction side.

[0255] The forms and actions of the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B will be described in more detail with reference to FIGS. 69 and 70.

[0256] First, the forms of the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B will be described. FIG. 69 is a diagram for explaining the form of the pair of liquid flow path convex portions 52 shown in FIG. 68. In the example shown in FIG. 69, the first liquid flow path convex portion 552A has a planar shape of a parallelogram composed of four points P1, Q1, R1, and S1, and the side connecting P1 and Q1 forms an angle θ1 with respect to the first direction (x direction). The angle θ1 can be in the range greater than 0° and less than 90°, but is preferably 30° or more and 60° or less.

[0257] As described above, the first liquid flow path convex portion 552A has a form that extends in a direction inclined with respect to the first direction (x direction) so as to proceed in the first direction (x direction) while proceeding from one side (the y direction side in the drawing) with respect to the liquid flow path groove 551 toward the liquid flow path groove 551. Therefore, the first communication groove 554A (the portion surrounded by a broken line in the drawing) formed between the first liquid flow path convex portions 552A arranged in the first direction (x direction) also has a form that extends in a direction inclined with respect to the first direction so as to proceed in the first direction (x direction) while proceeding from one side (y direction side) with respect to the liquid flow path groove 551 toward the liquid flow path groove 551.

[0258] Similarly, the second liquid flow path convex portion 552B has a planar shape of a parallelogram composed of four points P2, Q2, R2, and S2, and the side connecting P2 and Q2 forms an angle θ2 with respect to the first direction (x direction). The angle θ2 can also be in the range greater than 0° and less than 90°, but preferably, it is 30° or more and 60° or less.

[0259] As described above, the second liquid flow path convex portion 552B has a form that extends in a direction inclined with respect to the first direction so as to proceed in the first direction while proceeding from the side opposite to the one side with respect to the liquid flow path groove 551 (the side opposite to the y direction) toward the liquid flow path groove 551. Therefore, the second communication groove 554B (the portion surrounded by a broken line in the drawing) formed between the second liquid flow path convex portions 552B arranged in the first direction (x direction) also has a form that extends in a direction inclined with respect to the first direction so as to proceed in the first direction (x direction) while proceeding from the side opposite to the one side with respect to the liquid flow path groove 551 (the side opposite to the y direction) toward the liquid flow path 551.

[0260] Here, as in FIG. 68, in the example shown in FIG. 69, the first liquid flow path convex portion 552A constituting the pair of liquid flow path convex portions 552 and the second liquid flow path convex portion 552B adjacent via the main flow groove 551 are formed symmetrically with respect to the liquid flow path groove 551. In this case, the above-described angle θ1 and angle θ2 are equal. Also, in this case, the first communication groove 554A and the second communication groove 554B are also symmetric with respect to the liquid flow path 551.

[0261] By making it axisymmetric in this way, the design of the first liquid flow path convex portion row 553A and the second liquid flow path convex portion row 553B does not need to be complicated. Also, equalizing the actions of each pair of the liquid flow path convex portions 552 can be expected. For example, it can be expected to equalize the ease of entry of the liquid working fluid from each of the plurality of first communication grooves 554A and the plurality of second communication grooves 554B into the liquid flow path groove 551.

[0262] However, in this embodiment, the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B that constitute the pair of liquid flow path convex portions 552 do not have to be formed symmetrically with respect to the liquid flow path groove 551. When they are not formed symmetrically, for example, the following effects can be achieved.

[0263] For example, when the vapor of the working fluid flows in or is generated in the region sandwiched between the pair of liquid flow path convex portions 552, it is necessary to prevent this vapor from entering the evaporation portion (the portion close to the heat source). Here, in this embodiment, even when the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B that constitute the pair of liquid flow path convex portions 552 are not formed symmetrically with respect to the liquid flow path groove 551, even if the vapor of the working fluid tries to advance in the first direction (x direction), it is blocked by the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B, and the tendency to advance in the first direction (x direction) is reduced. Therefore, it is possible to prevent the vapor from advancing to the evaporation portion. The actions of the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B will be described in more detail with reference to FIG. 70, which will be described later.

[0264] Furthermore, in the vapor chamber 501 according to the present embodiment, the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B that constitute the pair of liquid flow path convex portions 552 is such that the distance on the first direction side is smaller than the distance on the side opposite to the first direction side. For example, as shown in FIG. 69, in the first liquid flow path convex portion 552A (a parallelogram composed of four points P1, Q1, R1, S1) and the second liquid flow path convex portion 552B (a parallelogram composed of four points P2, Q2, R2, S2), the distance D1 between the ends on the first direction (x direction) side (the distance between S1 and S2) is smaller than the distance D2 between the ends on the side opposite to the first direction (x direction) side (the distance between R1 and R2).

[0265] Next, the actions of the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B having the above-described form will be described. FIG. 70 is a diagram for explaining the actions of the pair of liquid flow path convex portions 552 shown in FIG. 69, and mainly shows the flow of the liquid working fluid and the flow of the vapor working fluid in the present embodiment. Here, in FIG. 70, the flow of the liquid working fluid is indicated by a thick solid arrow, and the flow of the vapor working fluid is indicated by a thick dashed arrow.

[0266] First, the flow of the liquid working fluid shown in FIG. 70 will be described. The first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B that constitute the pair of liquid flow path convex portions 552 have a form that extends in a direction inclined with respect to the first direction as described with reference to FIG. 69, and the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is such that the distance on the first direction side is smaller than the distance on the side opposite to the first direction side.

[0267] Therefore, in FIG. 70, as indicated by the thick solid arrow, the liquid working fluid present in the region sandwiched between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B that constitute the pair of liquid flow path convex portions 552 will advance from the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is large to the side where the distance is small due to capillary action.

[0268] That is, in this embodiment, a stronger driving force can be applied to the liquid working fluid existing in the region sandwiched between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B that constitute the pair of liquid flow path convex portions 552, and it can be transported in the first direction (x direction).

[0269] Further, in this embodiment, the depth of the region sandwiched between the pair of liquid flow path convex portions 552 can be formed such that the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is larger is deeper than the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is smaller.

[0270] By adopting such a form, more liquid working fluid can be stored in this region. And as described above, a stronger driving force can be applied to the liquid working fluid existing in this region and it can be transported in the first direction (x direction), that is, toward the evaporation portion V. Therefore, it is possible to prevent the liquid working fluid from being insufficient in the evaporation portion (the portion 4 close to the object to be cooled).

[0271] Also, by adopting the above-described form, the depth of the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is smaller becomes shallower. That is, since the cross-sectional area of the flow path on the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is smaller is smaller than that on the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is larger, the capillary action works more strongly. Therefore, a stronger driving force can be applied to the liquid working fluid in the liquid flow path groove 551, and the liquid flow path groove 551 (condensed liquid flow path 3) of the inner liquid flow path portion 538 can be transported in the first direction (x direction).

[0272] In addition, the liquid working fluid that has passed through the end on the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is small will diffuse in the region sandwiched between the next pair of liquid flow path convex portions 552. However, due to the pressure of this diffusion and the volume of the liquid working fluid present in the region sandwiched between the pair of liquid flow path convex portions 552, it is possible to more effectively prevent the vapor of the working fluid from entering the liquid flow path groove 551 (condensate flow path 3) from the first communication groove 554A and the second communication groove 554B.

[0273] The above-described form can be obtained, for example, by forming the liquid flow path portion 50 by half-etching using an etching solution. In half-etching using an etching solution, there is a property that the deeper the etched depth tends to be, the larger the area to be etched.

[0274] Therefore, for example, regarding the etching pattern used for forming the inner liquid flow path portion 538, with respect to the region sandwiched between the pair of liquid flow path convex portions 552, the area on the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is large (the above-mentioned D2 side) is made larger than the area on the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is small (the above-mentioned D1 side). As a result, regarding the depth of the region sandwiched between the pair of liquid flow path convex portions 552 formed by half-etching using an etching solution, the depth on the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is large (the above-mentioned D2 side) can be made deeper than the depth on the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is small (the above-mentioned D1 side).

[0275] Next, the flow of the working fluid in the form of vapor will be described. The first liquid flow path convex portion 552A, the second liquid flow path convex portion 552B, the first communication groove 554A, and the second communication groove 554B have a form that extends in a direction inclined with respect to the first direction, as described with reference to FIG. 69. Therefore, the vapor of the working fluid (indicated by a broken-line arrow in the figure) that diffuses in the direction opposite to the first direction (x direction) through the vapor flow path groove 42 (vapor flow path 4) hardly enters the liquid flow path groove 551 (condensate flow path 3) through the first communication groove 554A or the second communication groove 554B, which is generally in the opposite direction to the diffusion direction.

[0276] That is, as shown in FIG. 68, since the evaporation section (the portion close to the object to be cooled) 4 is located on the upper side (x direction side) in FIG. 70, in FIG. 70, the vapor pressure is high on the upper side (x direction side), and the vapor pressure is low on the lower side (the side opposite to the x direction). Therefore, the vapor of the working fluid hardly diffuses from the lower side (the side opposite to the x direction), where the pressure is low, to the upper side (x direction), where the pressure is high. That is, it is unlikely that the vapor of the working fluid flows from the lower side (the side opposite to the x direction) to the upper side (x direction) through the first communication groove 554A or the second communication groove 554B.

[0277] Furthermore, as described above, the liquid working fluid that has passed through the end portion on the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is small diffuses in the region sandwiched between the next pair of liquid flow path convex portions 552. Therefore, depending on the pressure of this diffusion and the volume of the liquid working fluid present in the region sandwiched between the pair of liquid flow path convex portions 552, it is possible to more effectively prevent the vapor of the working fluid from entering the liquid flow path groove 551 (condensate flow path 3) from the first communication groove 554A and the second communication groove 554B.

[0278] Therefore, according to the vapor chamber 501 of the present embodiment, it is possible to effectively prevent the working fluid in a vapor state from entering the liquid flow path groove 551 (condensate flow path 3) from the first communication groove 554A or the second communication groove 554B, improve the transport function of the liquid working fluid, and improve the heat transport efficiency.

[0279] Also, immediately after (instantaneously) the inflow of the vapor of the working fluid or the flashing (i.e., generation of vapor) of the liquid working fluid occurs in the liquid flow path groove 551 (condensate flow path 3), the vapor pressure is higher on the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B of the pair of liquid flow path convex portions 552 is smaller, and lower on the other side (the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is larger, or the first communication groove 554A side and the second communication groove 554B side).

[0280] Therefore, the vapor that has flowed in or been generated within the region sandwiched between the pair of liquid flow path convex portions 552 is more likely to proceed to the other side (the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is larger, or the first communication groove 554A side and the second communication groove 554B side) rather than proceeding to the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B of the pair of liquid flow path convex portions 552 is smaller. That is, the vapor that has flowed in or been generated within the region sandwiched between the pair of liquid flow path convex portions 552 is less likely to proceed in the first direction (x direction) within the liquid flow path groove 551 (condensate flow path 3).

[0281] Therefore, according to the vapor chamber 501 of the present embodiment, even when the temperature of the evaporation section V is high and evaporation is active, for example, even if vapor inflow or generation occurs in the liquid flow path groove 551 (condensate flow path 3), it is possible to prevent the inflowed or generated vapor from proceeding in the first direction (x direction) within the liquid flow path groove 551 (condensate flow path 3), improve the transport function of the liquid working fluid, and improve the heat transport efficiency.

[0282] Note that, as described above, the vapor that has flowed in or been generated within the region sandwiched between the pair of liquid flow path convex portions 552 is more likely to proceed to the other side (the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B is larger, or the first communication groove 554A side and the second communication groove 554B side) rather than proceeding to the side where the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B of the pair of liquid flow path convex portions 552 is smaller.

[0283] Here, since the pressure on the side where the distance between the first liquid flow path convex portions 552A and the second liquid flow path convex portions 552B of the pair of liquid flow path convex portions 552 where steam flows in or is generated, located on the side opposite to the first direction (x direction), is high, it is unlikely that the steam will flow into the pair of liquid flow path convex portions 552 located on the side opposite to the first direction (x direction) through this high-pressure area.

[0284] Therefore, the steam will be discharged into the steam flow path portion groove 42 (steam flow path 4) through the first communication groove 554A and the second communication groove 554B. Here, by designing the widths of the first communication groove 554A and the second communication groove 554B to be larger than the distance between the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B of the pair of liquid flow path convex portions 552, the above-described steam discharge effect can be further promoted.

[0285] Next, the details of the planar shapes (especially the corners) of the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B will be described with reference to FIG. 71. As will be described later, the inner liquid flow path portion 538 is formed by performing half-etching on the metal material sheet using an etching solution. Therefore, the planar shapes of the first liquid flow path convex portion 552A and the second liquid flow path convex portion 552B that constitute the pair of liquid flow path convex portions 552 are not strictly parallelograms, but rather have a form with rounded corners.

[0286] For example, as shown in FIG. 71, the first liquid flow path convex portion 552A is formed from a parallelogram (the parallelogram shown by the solid line in FIG. 71) composed of four points P1, Q1, R1, and S1, and the sharp corners are rounded to have curved portions 555 and 556 as shown by the dashed line. However, as long as the side 557 in the direction of the line connecting P1 and Q1 and the side 558 in the direction of the line connecting S1 and R1 remain, the above-described various effects in the vapor chamber 501 of the present embodiment can be achieved. The same applies to the second liquid flow path convex portion 552B.

[0287] 6.2. Configuration 6b Next, the vapor chamber according to Configuration 6b will be described with reference to FIG. 72. Note that the vapor chamber according to Form 6b has a different shape of its inner liquid flow path portion from that of the vapor chamber according to Form 6a, and for other configurations, it can be the same as the vapor chamber according to Form 6a.

[0288] FIG. 72 is a diagram showing an example of the inner liquid flow path portion 538' of the vapor chamber 501' according to Form 6b. More specifically, this FIG. 72 is a diagram corresponding to FIG. 69 in the vapor chamber 501'.

[0289] The liquid flow path portion of the vapor chamber according to this form has a plurality of liquid flow path grooves each extending in a first direction through which a liquid working fluid passes, and a plurality of convex portion rows extending in the first direction with the liquid flow path grooves interposed therebetween. The plurality of liquid flow path grooves include a liquid flow path groove as a reference. Each of the convex portion rows includes a plurality of liquid flow path convex portions arranged in the first direction through a plurality of connection grooves. The plurality of connection grooves include a first connection groove arranged on one side with respect to the reference main flow groove and a second connection groove arranged on the other side with respect to the reference main flow groove. The first connection groove extends in a direction inclined with respect to the first direction so as to advance in the first direction while advancing toward the reference main flow groove, and the second connection groove extends in a direction inclined with respect to the first direction so as to advance in the first direction while advancing toward the liquid flow path groove as a reference.

[0290] Also, the first connection grooves are aligned in the extending direction of the first connection groove, and the second connection grooves are aligned in the extending direction of the second connection groove.

[0291] For example, as shown in FIG. 72, the inner liquid flow path portion 538' of the vapor chamber 501' has three liquid flow path grooves (551', 551'A, 551'B) including a liquid flow path groove 551' as a reference. Each liquid flow path groove extends in the first direction (x direction).

[0292] In addition, the inner liquid flow path portion 538' of the vapor chamber 501' has four convex portion rows (553'A, 553'B, 553'C, 553'D) extending in the first direction. Among the four convex portion rows (553'A, 553'B, 553'C, 553'D), the convex portion row on one side (the Y direction side in the figure) of the reference main flow groove 551 is the first convex portion row (553'A, 553'B), and the convex portion row on the other side (the side opposite to the y direction in the figure) of the reference liquid flow path groove 551' is the second convex portion row (553'D, 553'C).

[0293] To put it more clearly, in the example shown in FIG. 72, in order from the y direction side in the figure, the first convex portion row 553'A, the liquid flow path groove 551'A, the first convex portion row 553'B, the reference main flow groove 551', the second convex portion row 553'D, the liquid flow path groove 551'B, and the second convex portion row 553'C are arranged.

[0294] The first convex portion row 553'A includes a plurality of liquid flow path convex portions 552'A arranged in the first direction (x direction) via a plurality of first connection grooves 554'A. Similarly, the first convex portion row 553'B includes a plurality of liquid flow path convex portions 552'B arranged in the first direction via a plurality of first connection grooves 554'B. In addition, the second convex portion row 553'D includes a plurality of liquid flow path convex portions 552'D arranged in the first direction via a plurality of second connection grooves 554'D. Further, the second convex portion row 553'C includes a plurality of liquid flow path convex portions 552'C arranged in the first direction via a plurality of second connection grooves 554'C.

[0295] And each of the first connection grooves 554'A and 554'B extends in a direction inclined with respect to the first direction so as to proceed in the first direction while proceeding from one side (y direction side) of the reference liquid flow path groove 551 toward the reference liquid flow path groove 551'.

[0296] In the example shown in FIG. 72, the angle formed by the extending direction of the first connection grooves 554'A and 554'B (the direction indicated by the thick dashed arrow in the figure) and the first direction (x direction) is defined as the angle θ3. The angle θ3 can be in the range greater than 0° and less than 90°, but preferably, it is 30° or more and 60° or less.

[0297] Further, each of the second communication channels 534'D and 554'C extends in a direction inclined with respect to the first direction while advancing from the other side (opposite side in the y direction) of the reference fluid flow path groove 551' toward the reference fluid flow path groove 551' in the first direction (x direction).

[0298] In the example shown in FIG. 72, the angle (the acute angle side angle) formed by the extending direction of the second communication grooves 554'D and 554'C (the direction indicated by the thick dashed arrow in the figure) and the first direction (x direction) is defined as angle θ4. Angle θ4 can be in the range greater than 0° and less than 90°, but preferably is 30° or more and 60° or less.

[0299] Also, each of the first communication grooves 554'A and 554'B is aligned in the extending direction of the first communication groove, and each of the second communication grooves 554'D and 554'C is aligned in the extending direction of the second communication groove.

[0300] For example, as shown in FIG. 72, the first communication grooves 554'A and 554'B are arranged in the direction in which the angle formed with the extending direction of the first communication groove, that is, the first direction (x direction), is angle θ3 (the direction indicated by the thick dashed arrow in the figure), and the second communication grooves 554'C and 554'D are arranged in the direction in which the angle formed with the extending direction of the second communication groove, that is, the first direction (x direction), is angle θ4 (the direction indicated by the thick dashed arrow in the figure).

[0301] With such an arrangement, the design of the plurality of first communication grooves and second communication grooves does not need to be complicated. Also, it can be expected to equalize the functions of the respective communication grooves. For example, it can be expected to equalize the ease of entry of the liquid working fluid from each of the plurality of first communication grooves and the plurality of second communication grooves into each fluid flow path groove (condensate flow path).

[0302] Also, as described above, since the vapor chamber 501’ has a plurality of liquid flow path grooves (551’, 551’A, 551B) and a plurality of convex part rows (553’A, 553’B, 555’C, 553’D) extending in the first direction with these liquid flow path grooves interposed therebetween, it is possible to make the concavo-convex structure of the inner liquid flow path part 538’ of the vapor chamber 501’ more complex and increase the surface area of the inner liquid flow path part 538’. Therefore, the transport amount of the working fluid by capillary action can be further increased, and the transport efficiency can be further improved.

[0303] Also, the first communication groove 554’A and the second communication groove 554’C included in the vapor chamber 501’ have a form extending in a direction inclined with respect to the first direction. Therefore, similar to the vapor chamber 501 of the above-described form 6a, the working fluid of the vapor diffusing in the direction opposite to the first direction (x direction) through the vapor flow path 4 is expected to have the effect of being less likely to enter the liquid flow path groove through the first communication groove 554’A or the second communication groove 554’C, which is generally in the opposite direction to this diffusion direction.

[0304] 6.3. Form 6c Next, with reference to FIG. 73, the vapor chamber according to Form 6c will be described.

[0305] As described above, the first communication groove 554’A and the second communication groove 554’C included in the vapor chamber 501’ according to Form 6b have a form extending in a direction inclined with respect to the first direction. Therefore, similar to the vapor chamber 501 according to Form 6a, the working fluid of the vapor diffusing in the direction opposite to the first direction (x direction) through the vapor flow path part is expected to have the effect of being less likely to enter the liquid flow path groove through the first communication groove 554’A or the second communication groove 554’C, which is generally in the opposite direction to this diffusion direction.

[0306] However, in the vapor chamber 501', unlike the vapor chamber 501 in Form 6a, the distance (D3) between adjacent liquid flow path protrusions is constant (see Fig. 72). That is, in the vapor chamber 501' shown in Fig. 72, the distance between the first liquid flow path protrusion and the second liquid flow path protrusion that form a pair of liquid flow path protrusions, like the vapor chamber 501 in Form 6a, is not in the form where the distance on the first direction side is smaller than the distance on the side opposite to the first direction side.

[0307] More specifically, in the vapor chamber 501 in Form 6a, as shown in Fig. 69, the distance between the first liquid flow path protrusion 552A and the second liquid flow path protrusion 552B has a form where the distance (D1) on the first direction side (x direction side) is smaller than the distance (D2) on the side opposite to the first direction side.

[0308] And because it has such a form, the liquid working fluid that has passed through the end on the side where the distance between the first liquid flow path protrusion 552A and the second liquid flow path protrusion 552B is small will diffuse in the region sandwiched by the next pair of liquid flow path protrusions 552. Then, due to the pressure of this diffusion and the volume of the liquid working fluid present in the region sandwiched by the pair of liquid flow path protrusions 552, it is expected that the vapor working fluid can be more effectively prevented from entering the liquid flow path portion 551 (condensate flow path 3) from the first communication groove 554A and the second communication groove 554B.

[0309] On the other hand, in the vapor chamber 501' in Form 6b, as shown in Fig. 72, the distance (D3) between the adjacent liquid flow path protrusions 552'B and 552'D is constant, and the distance on the first direction side (x direction side) is the same as the distance on the side opposite to the first direction side.

[0310] Therefore, regarding the effect like that of the vapor chamber 501 in Form 6a, that is, the effect that the vapor working fluid can be more effectively prevented from entering the reference liquid flow path groove 551' (condensate flow path 3) from the first communication groove 554'B and the second communication groove 554'D, the vapor chamber 501 is more preferable.

[0311] Furthermore, in the vapor chamber 501' shown in FIG. 72, each of the first communication grooves 554'A and 554'B is aligned in the extending direction of the first communication groove, and each of the second communication grooves 554'D and 554'C is aligned in the extending direction of the second communication groove.

[0312] For example, as shown in FIG. 72, the first communication grooves 554'A and 554'B are arranged in a direction at an angle θ3 with respect to the extending direction of the first communication groove, that is, the first direction (x-direction) (the direction indicated by the thick dashed arrow in the figure), and the second communication grooves 554'C and 554'D are arranged in a direction at an angle θ4 with respect to the extending direction of the second communication groove, that is, the first direction (x-direction) (the direction indicated by the thick dashed arrow in the figure).

[0313] Therefore, the working fluid of the vapor that has entered from the first communication groove 554'A, which is located more outside the reference liquid flow path groove 551', may pass through the more inner first communication groove 554'B as well because there is no liquid flow path convex portion in the extending direction of this first communication groove, and may easily enter the reference liquid flow path groove 551' (condensate flow path 3). Similarly, the working fluid of the vapor that has entered from the second communication groove 554'C, which is located more outside the reference liquid flow path groove 551', may pass through the more inner second communication groove 554'D as well because there is no liquid flow path convex portion in the extending direction of this second communication groove, and may easily enter the reference liquid flow path groove 551' (condensate flow path 3).

[0314] Therefore, in the vapor chamber according to Form 6c, a form is adopted in which a liquid flow path convex portion exists in the extending direction of the communication groove. Note that the form of the inner liquid flow path portion of the vapor chamber in Form 6c is different from that of the vapor chambers according to Forms 6a and 6b, and other configurations can be the same as those of the vapor chamber according to Form 6a above.

[0315] FIG. 73 is a diagram showing an example of the inner liquid flow path portion 538” of the vapor chamber 501” according to Form 6c. As shown in FIG. 73, the inner liquid flow path portion 538” of the vapor chamber 501” has three liquid flow path grooves (551”, 551”A, 551”B) including a reference liquid flow path groove 551”. Each liquid flow path groove extends in the first direction (x direction).

[0316] Further, the inner liquid flow path portion 538” of the vapor chamber 501” has four convex portion rows (553”A, 553”B, 553”C, 553”D) extending in the first direction. Among the four convex portion rows (553”A, 553”B, 553”C, 553”D), the convex portion rows on one side (y direction side) of the reference liquid flow path groove 551” are the first convex portion rows (553”A, 553”B), and the convex portion rows on the other side (opposite to the y direction) of the reference liquid flow path groove 551” are the second convex portion rows (553”D, 553”C).

[0317] More specifically, in the example shown in FIG. 73, in order from the y direction side, the first convex portion row 553”A, the liquid flow path groove 551”A, the first convex portion row 553”B, the reference liquid flow path groove 551”, the second convex portion row 553”D, the liquid flow path groove 551”B, and the second convex portion row 553”C are arranged.

[0318] The first convex portion row 553”A includes a plurality of liquid flow path convex portions 552”A arranged in the first direction (x direction) via a plurality of first connection grooves 554”A. Similarly, the first convex portion row 553”B includes a plurality of liquid flow path convex portions 552”B arranged in the first direction via a plurality of first connection grooves 554”B. Further, the second convex portion row 553”D includes a plurality of liquid flow path convex portions 552”D arranged in the first direction via a plurality of second connection grooves 554”D. Also, the second convex portion row 553”C includes a plurality of liquid flow path convex portions 552”C arranged in the first direction via a plurality of second connection grooves 554”C.

[0319] Then, each of the first communication grooves 554”A and 554”B extends in a direction inclined with respect to the first direction so as to proceed in the first direction (x direction) while proceeding from one side (y direction side) of the reference liquid flow path groove 551” toward the reference liquid flow path groove 551”. In the example shown in FIG. 73, the angle (the acute angle side angle) formed by the extending direction of the first communication groove 554”A (the direction indicated by the thick broken line arrow in the figure) and the first direction (x direction) is defined as angle θ5. The angle θ5 can be in the range greater than 0° and less than 90°, but preferably, it is 30° or more and 60° or less.

[0320] Also, each of the second communication grooves 554”D and 554”C extends in a direction inclined with respect to the first direction so as to proceed in the first direction (x direction) while proceeding from the other side (the opposite side of the y direction) of the reference liquid flow path groove 551” toward the reference liquid flow path groove 551”. In the example shown in FIG. 73, the angle (the acute angle side angle) formed by the extending direction of the second communication groove 554”C (the direction indicated by the thick broken line arrow in the figure) and the first direction (x direction) is defined as angle θ6. The angle θ6 can be in the range greater than 0° and less than 90°, but preferably, it is 30° or more and 60° or less.

[0321] Here, in the vapor chamber of the present embodiment, in a pair of adjacent first convex portion rows, the first convex portion row arranged outside with respect to the reference liquid flow path groove is defined as the outer first convex portion row, and the first convex portion row arranged inside with respect to the reference liquid flow path groove is defined as the inner first convex portion row. In a pair of adjacent second convex portion rows, the second convex portion row arranged outside with respect to the reference liquid flow path groove is defined as the outer second convex portion row, and the second convex portion row arranged inside with respect to the reference liquid flow path groove is defined as the inner second convex portion row. When this is the case, the liquid flow path convex portions constituting the inner first convex portion row are arranged in the extending direction of the first communication groove passing between the liquid flow path convex portions constituting the outer first convex portion row, and the liquid flow path convex portions constituting the inner second convex portion row are arranged in the extending direction of the second communication groove passing between the liquid flow path convex portions constituting the outer second convex portion row.

[0322] For example, in the vapor chamber 501” shown in FIG. 73, the first convex portion row 553”A is the outer first convex portion row, and the first convex portion row 553”B is the inner first convex portion row. Similarly, the second convex portion row 553”C is the outer second convex portion row, and the second convex portion row 553”D is the inner second convex portion row.

[0323] And in the direction in which the first communication groove 554”A extending between the fluid flow path convex portions 552”A constituting the first convex portion row 553”A, which is the outer first convex portion row, extends (the direction indicated by the thick dashed arrow in the figure), the fluid flow path convex portions 552”B constituting the first convex portion row 553”B, which is the inner first convex portion row, are arranged.

[0324] Therefore, the working fluid of the vapor that has entered from the first communication groove 554”A, which is more outside with respect to the reference fluid flow path groove 551”, is blocked by the fluid flow path convex portions 552”B existing in the extending direction of this first communication groove, and it becomes difficult to enter the reference fluid flow path groove 551” that is more inside. Also, since the flow of the vapor is dispersed by the fluid flow path convex portions 552”B, the pressure of the vapor also decreases. Therefore, furthermore, it becomes difficult to enter the reference fluid flow path groove 551”.

[0325] Similarly, in the direction in which the second communication groove 554”C extending between the fluid flow path convex portions 552”C constituting the second convex portion row 553”C, which is the outer second convex portion row, extends (the direction indicated by the thick dashed arrow in the figure), the fluid flow path convex portions 552”D constituting the second convex portion row 553”D, which is the inner second convex portion row, are arranged.

[0326] Therefore, the working fluid of the vapor that has entered from the second communication groove 554”C, which is more outside with respect to the reference fluid flow path groove 551”, is blocked by the fluid flow path convex portions 552”D existing in the extending direction of this first communication groove, and it becomes difficult to enter the reference fluid flow path groove 551” that is more inside. Also, since the flow of the vapor is dispersed by the fluid flow path convex portions 552”D, the pressure of the vapor also decreases. Therefore, furthermore, it becomes difficult to enter the reference fluid flow path groove 551”.

[0327] Therefore, according to the "vapor chamber 501", it can effectively prevent the working fluid of the vapor from entering the reference liquid flow path groove 551", improve the transport function of the liquid working fluid, and improve the heat transport efficiency.

[0328] Also, similar to the vapor chamber 501' shown in FIG. 72, the vapor chamber 501" has a plurality of liquid flow path grooves (551", 551"A, 551"B) and a plurality of convex part arrays (553"A, 553"B, 553"C, 553"D) extending in the first direction with these liquid flow path grooves interposed therebetween. Therefore, it is possible to make the concavo-convex structure of the inner liquid flow path portion 538" of the vapor chamber 501" more complex and increase the surface area of the inner liquid flow path portion 538". Therefore, the amount of the working fluid transported by capillary action can be further increased, and the transport efficiency can be further improved.

[0329] Each of the above-described embodiments of the present disclosure is not limited as it is, and the components can be modified and embodied without departing from the gist thereof. Also, various forms in which the components disclosed in the above embodiments are combined in plurality can be adopted to achieve effects. Some components may be deleted from all the components shown in each form, or only one or some of the components may be used from the viewpoint of obtaining necessary effects.

Explanation of Reference Numerals

[0330] 1, 51 Vapor chamber 2 Sealed space 3 Condensate flow path 4 Vapor flow path 10 First sheet 11 Main body 12 Injection part 20 Second sheet 21 Main body 22 Injection part 30, 52 Third sheet 31, 53 Main body 32 Injection part 33 Outer peripheral joint part 34 Outer peripheral liquid flow path part (liquid flow path part) 37 Introduction part 38, 54 Inner liquid flow path part (liquid flow path part) 41 Introduction part 42 Vapor flow path groove 44 Vapor flow path communication groove 54a Thickness direction communication hole 80 Electronic device 81 Housing 83 Electronic component 101 Vapor chamber 130 Third sheet 131 Body 134 Outer peripheral liquid flow path part (liquid flow path part) 136 Heat insulation part groove 138 Inner liquid flow path part (liquid flow path part) 140 Heat insulation part groove 201 Vapor chamber 230 Third sheet 238 Inner liquid flow path part (liquid flow path part) 241 Introduction part 301 Vapor chamber 310 First sheet 311 Inner sheet 312 Reinforcing sheet 320 Second sheet 321 Inner sheet 322 Reinforcing sheet 401 Vapor chamber 410 First sheet 411 Inner sheet 413 Barrier sheet 420 Second sheet 423 Barrier sheet 501 Vapor chamber 538 Inner liquid flow path part 551 Vapor flow path groove 552 Pair of liquid flow path convex parts 552A First liquid flow path convex part 552B Second liquid flow path convex part 553A First liquid flow path convex part row 553B Second liquid flow path convex part row 554A First connection groove 554B Second connection groove

Claims

1. A sheet for a vapor chamber in which a working fluid is sealed in an enclosed space, comprising: The sheet for the vapor chamber has a first surface and a second surface opposite to the first surface, The sheet has a second flow path provided on the first surface and a first flow path provided penetrating from the first surface to the second surface of the sheet, the second flow path communicates with the first flow path through a wall surface of the first flow path by a plurality of communication openings; The wall surface has a top portion that protrudes most toward the inside of the first flow path, The wall surface is inclined from the top portion toward the first surface in a cross-sectional view. Sheet for vapor chamber.

2. A sheet for a vapor chamber in which a working fluid is sealed in an enclosed space, comprising: The sheet for the vapor chamber has a first surface and a second surface opposite to the first surface, The sheet has a second flow path provided on the first surface and a first flow path provided penetrating from the first surface to the second surface of the sheet, the second flow path communicates with the first flow path via a wall surface of the first flow path, The wall surface has a top portion that protrudes most toward the inside of the first flow path, The wall surface is arc-shaped in cross section from the top portion toward the first surface. Sheet for vapor chamber.

3. A sheet for a vapor chamber as described in claim 1 or 2, wherein the value obtained by dividing the thickness direction distance from the first surface to the top by the thickness of the first flow path is greater than or equal to 0.05 and less than or equal to 1.

0.

4. A sheet for a vapor chamber in which a working fluid is sealed in an enclosed space, comprising: The sheet for the vapor chamber has a first surface and a second surface opposite to the first surface, The sheet has a second flow path provided on the first surface and a first flow path provided penetrating from the first surface to the second surface of the sheet, the second flow path communicates with the first flow path via a wall surface of the first flow path, The wall surface has a top portion that protrudes most toward the inside of the first flow path, The top portion is located closer to the first surface than the center of the sheet for the vapor chamber in the thickness direction. Sheet for vapor chamber.

5. A sheet for a vapor chamber described in any one of claims 1 to 4, wherein the wall surface is a concave arc from the top toward the first surface when viewed in cross section.

6. A sheet for a vapor chamber described in any one of claims 1 to 4, wherein the wall surface is a convex arc from the top toward the first surface when viewed in cross section.

7. A second flow path is formed on the second surface, The sheet for a vapor chamber according to any one of claims 1 to 6, wherein the other second flow path is connected to the first flow path via a wall surface of the first flow path extending from the top portion toward the second surface.

8. A sheet for a vapor chamber described in any one of claims 1 to 7, wherein the sheet is a single layer.

9. A sheet for a vapor chamber described in any one of claims 1 to 7, wherein the sheet is formed by stacking multiple sheets.

10. A first sheet; A second sheet; The sheet for a vapor chamber according to any one of claims 1 to 9, which is disposed between the first sheet and the second sheet. Vapor chamber.

11. An electronic device equipped with a vapor chamber as described in claim 10.

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