Vapor chamber and electronic apparatus

Abstract

To provide a vapor chamber that can enhance heat transport capacity even when having a flow channel of which direction changes.SOLUTION: A vapor chamber includes a sealed space in which a working fluid is encapsulated. The sealed space includes: a capillary structure through which the working fluid moves in a state of condensate liquid; and a plurality of steam flow passages through which the working fluid moves in the state of vapor and condensate liquid; and a curved part in which a direction in which the plurality of steam flow passages extends changes.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a vapor chamber that performs heat transport while a working fluid enclosed in a sealed space moves.

Background Art

[0002] In electronic devices typified by personal computers and portable devices such as mobile phones and tablet terminals, electronic components such as CPUs (Central Processing Units) are used. Since the amount of heat generated from such electronic components tends to increase with the improvement of information processing capabilities, technologies for cooling them have become important. Heat pipes are well known as means for cooling. This is a device that utilizes the phase change of a working fluid enclosed in a pipe to transport heat at a heat source to other parts and diffuse it, thereby cooling the heat source.

[0003] On the other hand, in recent years, the thinning of these electronic devices has been remarkable, and a cooling means thinner than conventional heat pipes has been required. In response to this, vapor chambers have been proposed. A vapor chamber is sometimes called a sheet-type heat pipe and is a device that extends the concept of heat transport by a heat pipe to a flat member. That is, in a vapor chamber, a working fluid is enclosed between opposing flat plates, and the heat at a heat source is transported and diffused by utilizing the phase change of this working fluid to cool the heat source.

[0004] Although such a vapor chamber is disposed inside an electronic device, since many other members are also disposed inside the electronic device, there are often restrictions on the positions where the vapor chamber can be disposed. Then, it is not always possible to form a vapor chamber having a straight flow path. For example, as described in Patent Document 1, it is necessary to provide a flow path having a curved portion whose direction changes to cope with the restrictions on the arrangement.

Prior Art Documents

Patent Documents

[0005] Patent Document 1 Japanese Patent Application Laid-Open No. 2016-205693 Summary of the Invention Problems to be Solved by the Invention

[0006] However, in the vapor chamber having a flow path whose direction changes as described in Patent Document 1, there has been a problem that it is difficult to enhance the heat transport capacity.

[0007] Therefore, in view of the above problems, an object of the present invention is to provide a vapor chamber capable of enhancing the heat transport capacity even when having a flow path whose direction changes. Another object is to provide an electronic device including this vapor chamber. Means for Solving the Problems

[0008] As a result of intensive studies, the inventors have found that in a vapor chamber having a plurality of vapor flow paths whose directions change, since the lengths are different among the plurality of vapor flow paths, there is a large difference in the flow resistance, which is the resistance when the working fluid moves through the flow paths, between the flow paths, and thus the working fluid does not move in a well-balanced manner. And it has been found that due to the large difference in the flow resistance, the heat transport capacity decreases and the assumed performance cannot be achieved. Based on these findings, the inventors have embodied and completed the present invention. The present invention will be described below.

[0009] The present application discloses a vapor chamber in which a working fluid is enclosed in a sealed space, and the sealed space is provided with a capillary structure through which the working fluid moves in a condensate state and a plurality of vapor flow paths through which the working fluid moves in a vapor and condensate state, and has a curved portion where the extending directions of the plurality of vapor flow paths change. The plurality of vapor flow paths are arranged at intervals from each other at the curved portion, and at the curved portion, the center position of the arc of the radius of curvature of at least one vapor flow path is shifted with respect to the center position of the arc of the radius of curvature of another vapor flow path. Advantages of the Invention

[0010] According to the present invention, even when the vapor chamber has a flow path with a changing direction, the heat transport capacity can be enhanced.

Brief Description of the Drawings

[0011]

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Embodiments for Carrying Out the Invention

[0012] Hereinafter, each embodiment will be described with reference to the drawings. However, the present invention is not limited to these embodiments. In the following drawings, for clarity, the sizes and ratios of the members may be changed or exaggerated. Also, for clarity, the illustration of parts that are not necessary for explanation and repeated reference numerals may be omitted.

[0013] Fig. 1(a) shows an external perspective view of the vapor chamber 1 according to the first embodiment, and Fig. 1(b) 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 orthogonal to each other are also shown. Here, the direction in the xy plane is the direction along the plate surface of the vapor chamber 1 which is flat plate-shaped, and the z direction is the thickness direction.

[0014] As can be seen from Fig. 1(a) and Fig. 1(b), the vapor chamber 1 of this embodiment has a first sheet 10 and a second sheet 20. And, as will be described later, by overlapping and joining (diffusion bonding, brazing, etc.) the first sheet 10 and the second sheet 20, a hollow portion is formed between the first sheet 10 and the second sheet 20, and a working fluid is enclosed in this hollow portion to form a sealed space 2 (see, for example, Fig. 13).

[0015] In this embodiment, the first sheet 10 is a sheet-like member as a whole and is L-shaped in plan view. Fig. 2 shows a perspective view of the first sheet 10 seen from the inner surface 10a side, and Fig. 3 shows a plan view of the first sheet 10 seen from the inner surface 10a side. Also, Fig. 4 shows a cross-sectional view of the first sheet 10 when cut along IV-IV of Fig. 3. The first sheet 10 includes an inner surface 10a, an outer surface 10b on the side opposite to the inner surface 10a, and a side surface 10c that forms the thickness across the inner surface 10a and the outer surface 10b, and a pattern for a flow path through which the working fluid moves is formed on the inner surface 10a side. As will be described later, by overlapping the inner surface 10a of the first sheet 10 and the inner surface 20a of the second sheet 20 so as to face each other, a hollow portion is formed, and a working fluid is enclosed here to become a sealed space 2.

[0016] The thickness of the first sheet 10 is not particularly limited, but is preferably 0.01 mm or more and 1.0 mm or less, and more preferably 0.05 mm or more and 0.2 mm or less. This can increase the number of scenarios where it can be applied as a thin-type vapor chamber.

[0017] The first sheet 10 includes a main body 11 and an injection part 12. The main body 11 is in the shape of a sheet that forms a part where the working fluid moves, and in this embodiment, it is L-shaped with a curved part in plan view. The injection part 12 is a part for injecting the working fluid into the hollow part formed by the first sheet 10 and the second sheet 20. In this embodiment, it is in the shape of a quadrangular sheet in plan view that protrudes from the L-shape of the main body 11 in plan view. In this embodiment, the injection part 12 of the first sheet 10 has flat surfaces on both the inner surface 10a side and the outer surface 10b side.

[0018] A structure for the working fluid to move is formed on the inner surface 10a side of the main body 11. Specifically, the structure includes an outer peripheral joint part 13, an outer peripheral fluid flow path part 14, an inner fluid flow path part 15, a vapor flow path groove 16, and a vapor flow path communication groove 17 on the inner surface 10a side of the main body 11.

[0019] The outer peripheral joint part 13 is a surface formed along the outer periphery of the main body 11 on the inner surface 10a side of the main body 11. When this outer peripheral joint part 13 overlaps and is joined (diffusion bonding, brazing, etc.) with the outer peripheral joint part 23 of the second sheet 20, a sealed space 2 is formed between the first sheet 10 and the second sheet 20, and the working fluid is sealed therein. As shown by A in FIGS. 3 and 4 10 The width of the outer peripheral joint part 13 shown can be appropriately set as needed, but it is preferably at least 0.05 mm and at most 5.0 mm at the smallest. If this width is less than 0.05 mm, there is a risk that the joint area will be insufficient when misalignment occurs during the joining of the first sheet and the second sheet. Also, if this width is greater than 5.0 mm, there is a risk that the internal volume of the sealed space will become small and the vapor flow path and condensate flow path cannot be sufficiently secured.

[0020] The outer peripheral liquid flow path portion 14 functions as a liquid flow path portion and is a part that constitutes a part of the condensate flow path 3 (see, for example, FIG. 14) through which the working fluid passes when it condenses and liquefies. FIG. 5(a) shows the portion indicated by the arrow Va in FIG. 4, and FIG. 5(b) shows the cross-sectional view taken along Vb-Vb in FIG. 3. The cross-sectional shape of the outer peripheral liquid flow path portion 14 appears in both figures. Further, FIG. 6 shows an enlarged plan view of the outer peripheral liquid flow path portion 14 viewed from the direction indicated by the arrow VI in FIG. 5(a).

[0021] As can be seen from these figures, the outer peripheral liquid flow path portion 14 is formed along the inner side of the outer peripheral joint portion 13 among the inner surfaces 10a of the main body 11 and is provided so as to be annular along the outer periphery of the sealed space 2. Further, in the outer peripheral liquid flow path portion 14, a plurality of liquid flow path grooves 14a that extend parallel to the outer peripheral direction of the main body 11 are formed, and the plurality of liquid flow path grooves 14a are arranged with intervals in a direction different from the direction in which the liquid flow path grooves 14a extend. Therefore, as can be seen from FIGS. 5(a) and 5(b), in the outer peripheral liquid flow path portion 14, the liquid flow path grooves 14a that are concave portions in the cross section and the walls 14b that are convex portions between the liquid flow path grooves 14a are repeatedly formed with unevenness. Here, since the liquid flow path groove 14a is a groove, in its cross-sectional shape, it includes a bottom portion and an opening existing at a portion on the opposite side facing the bottom portion.

[0022] By providing a plurality of liquid flow path grooves 14a in this way, the depth and width of each liquid flow path groove 14a can be reduced, the flow path cross-sectional area of the condensate flow path 3 (see, for example, FIG. 14) can be reduced, and a large capillary force can be utilized. On the other hand, by providing a plurality of liquid flow path grooves 14a, an appropriate internal volume of the condensate flow path 3 as a whole is ensured, and the condensate with a required flow rate can be flowed.

[0023] Furthermore, in the outer peripheral liquid flow path portion 14, as can be seen from FIG. 6, adjacent liquid flow path grooves 14a communicate with each other through communication openings 14c provided with a gap in the wall 14b. This promotes equalization of the amount of condensate between the plurality of liquid flow path grooves 14a, and the condensate can flow efficiently. In addition, the communication opening 14c provided in the wall 14b adjacent to the vapor flow path groove 16 forming the vapor flow path 4 communicates the vapor flow path 4 and the condensate flow path 3. Therefore, by configuring the communication opening 14c, the condensate generated in the vapor flow path 4 can be smoothly moved to the condensate flow path 3, and the vapor generated in the condensate flow path 3 can also be smoothly moved to the vapor flow path 4, thereby also promoting smooth movement of the working fluid.

[0024] In this embodiment, as shown in FIG. 6, the communication openings 14c are arranged so as to face the same position in the direction in which the liquid flow path grooves 14a extend across the groove of one liquid flow path groove 14a. However, the present invention is not limited to this. For example, as shown in FIG. 7, the communication openings 14c may be arranged at different positions in the direction in which the liquid flow path grooves 14a extend across the groove of one liquid flow path groove 14a. That is, in this case, the communication openings 14c are arranged offset in the direction in which the liquid flow path grooves 14a extend. By providing the communication openings 14c offset in this way, when viewed from the working fluid flowing through the condensate flow path 3, the communication openings 14c do not appear on both sides at the same time, and even if the communication openings 14c appear, the wall 14b always exists on at least one side surface. Therefore, capillary force can be continuously obtained. From this perspective, by forming the communication openings 14c offset, the capillary force acting on the working fluid can be maintained high, so that the condensate can flow smoothly.

[0025] The outer peripheral liquid flow path portion 14 having the above configuration preferably further has the following configuration. In FIGS. 3, 4, 5(a), and 5(b), B 10The width of the outer peripheral liquid flow path portion 14 shown in can be appropriately set according to the size of the entire vapor chamber and the like, but it is preferably 0.03 mm or more and 2 mm or less. If this width is less than 0.03 mm, there is a risk that the amount of liquid flowing outside cannot be sufficiently obtained. Also, if this width exceeds 2 mm, there is a risk that sufficient space for the inner condensate flow path and vapor flow path cannot be secured.

[0026] Regarding the liquid flow path groove 14a, the groove width indicated by C1 in FIGS. 5(a) and 6 is preferably 10 μm or more and 300 μm or less. Also, the depth of the liquid flow path groove 14a indicated by D in FIGS. 5(a) and 5(b) is preferably 5 μm or more and 200 μm or less. Thereby, the capillary force of the liquid flow path necessary for the condensate to flow can be sufficiently exerted. Here, the depth D of the liquid flow path groove is preferably smaller than the remaining sheet thickness obtained by subtracting the depth D of the groove from the thickness of the first sheet 10. Thereby, it is possible to more reliably prevent the sheet from being broken when the working fluid freezes. From the viewpoint of more strongly exerting the capillary force of the flow path, the aspect ratio (length-to-width ratio) in the cross section of the flow path represented by the value obtained by dividing C1 by D is preferably greater than 1.0 or less than 1.0. Among them, from the viewpoint of manufacturing, it is preferable that C1 is greater than D, and the aspect ratio is preferably greater than 1.3.

[0027] Regarding the wall 14b, the width indicated by C2 in FIGS. 5(a) and 6 is preferably 20 μm or more and 300 μm or less. If this width is less than 20 μm, it is likely to break due to repeated freezing and melting of the working fluid. If this width exceeds 300 μm, the width of the communication opening 14c becomes too large, and there is a risk of hindering the smooth communication of the working fluid with the adjacent condensate flow path 3.

[0028] Regarding the communication opening 14c, the size of the opening along the direction in which the liquid flow path groove 14a indicated by C3 in FIG. 6 extends is preferably 20 μm or more and 180 μm or less. Also, the pitch of adjacent communication openings 14c in the direction in which the liquid flow path groove 14a shown by C4 in FIG. 6 extends is preferably 300 μm or more and 2700 μm or less.

[0029] In this embodiment, the cross-sectional shape of the liquid flow path groove 14a is semi-elliptical, but it is not limited thereto, and may be a quadrangle such as a square, a rectangle, a trapezoid, a triangle, a semi-circle, a semi-circle at the bottom, a semi-ellipse at the bottom, or a combination thereof.

[0030] Also, the liquid flow path groove 14a is preferably formed continuously along the edge in the sealed space. That is, the liquid flow path groove 14a preferably extends annularly over one circumference without being interrupted by other components. This reduces the factors that inhibit the movement of the condensate, so that the condensate can be moved smoothly.

[0031] In this embodiment, the outer peripheral liquid flow path portion 14 is provided, but the outer peripheral liquid flow path portion 14 is not necessarily provided, and from the viewpoints of the shape of the vapor chamber, the relationship between the vapor chamber and the device to which it is applied, and the use environment, etc., a form in which the outer peripheral liquid flow path portion 14 is not provided may also be adopted. In this form, the outer peripheral portion can be used as a vapor flow path, and heat can be transported by vapor to the outer peripheral portion of the vapor chamber, and further heat uniformity may be achieved in some cases.

[0032] Returning to FIGS. 2 to 4, the inner liquid flow path portion 15 will be described. The inner liquid flow path portion 15 also functions as a liquid flow path portion and is a part that constitutes a part of the condensate flow path 3 through which the working fluid condenses and liquefies. FIG. 8(a) shows the portion indicated by VIIIa in FIG. 4. The cross-sectional shape of the inner liquid flow path portion 15 also appears in this figure. FIG. 8(b) shows an enlarged plan view of the inner liquid flow path portion 15 viewed from the direction indicated by the arrow VIIIb in FIG. 8(a).

[0033] As can be seen from these figures, the inner liquid flow path portion 15 is formed inside the ring of the annular outer liquid flow path portion 14 (or the outer peripheral joint portion 13) on the inner surface 10a of the main body 11. As can be seen from FIGS. 2 and 3, the inner liquid flow path portion 15 of the present embodiment is a ridge that has a curved portion and extends, and a plurality (five in the present embodiment) of inner liquid flow path portions 15 are arranged at intervals in a direction different from the direction in which they extend, and are arranged between the vapor flow path grooves 16. In each inner liquid flow path portion 15, a liquid flow path groove 15a, which is a groove parallel to the direction in which the inner liquid flow path portion 15 extends, is formed, and a plurality of liquid flow path grooves 15a are arranged at a predetermined interval in a direction different from the direction in which the liquid flow path grooves 15a extend. Therefore, as can be seen from FIGS. 4 and 8(a), in the inner liquid flow path portion 15, a liquid flow path groove 15a, which is a concave portion in its cross section, and a wall 15b, which is a convex portion between the liquid flow path grooves 15a, are repeatedly formed with irregularities. Here, since the liquid flow path groove 15a is a groove, in its cross-sectional shape, it includes a bottom portion and an opening existing at a portion on the opposite side facing the bottom portion.

[0034] By providing a plurality of liquid flow path grooves 15a in this way, the depth and width of each liquid flow path groove 15a can be reduced, the flow path cross-sectional area of the condensate flow path 3 (see, for example, FIG. 14) can be reduced, and a large capillary force can be utilized. On the other hand, by providing a plurality of liquid flow path grooves 15a, an appropriate total internal volume of the condensate flow path 3 as a whole is ensured, and a condensate with a required flow rate can flow through.

[0035] Furthermore, as can be seen from FIG. 8(b), in the inner liquid flow path portion 15 as well, adjacent liquid flow path grooves 15a are communicated with each other in the same manner as in FIG. 6 following the example of the outer peripheral liquid flow path portion 14, by communication openings 15c provided with intervals in the wall 15b. As a result, equalization of the amount of condensate is promoted among the plurality of liquid flow path grooves 15a, and the condensate can flow efficiently. Also, the communication openings 15c provided in the wall 15b adjacent to the vapor flow path grooves 16 forming the vapor flow path 4 communicate the vapor flow path 4 and the condensate flow path 3. Therefore, by configuring the communication openings 15c as will be described later, the condensate generated in the vapor flow path 4 can be smoothly moved to the condensate flow path 3, and the vapor generated in the condensate flow path can also be smoothly moved to the vapor flow path 4, and this also enables the smooth movement of the working fluid to be promoted.

[0036] Regarding the inner liquid flow path portion 15 as well, following the example of FIG. 7, the communication openings 15c may be arranged at different positions in the direction in which the liquid flow path grooves 15a extend with the groove of one liquid flow path groove 15a interposed therebetween. By providing the communication openings 15c offset in this way, when viewed from the working fluid traveling in the condensate flow path 3, the communication openings 15c do not appear on both sides at the same time, and at least one side surface always has the wall 15b present even when the communication openings 15c appear. Therefore, capillary force can be continuously obtained. From such a viewpoint, by forming the communication openings 15c offset, the capillary force acting on the working fluid can be maintained high, so that the working fluid can move more smoothly.

[0037] The inner liquid flow path portion 15 having the above-described configuration preferably further has the following configuration. In FIGS. 3, 4, and 8(a), E 10 The width of the inner liquid flow path portion 15 shown in is preferably 100 μm or more and 2000 μm or less. Also, the pitch of the plurality of inner liquid flow path portions 15 is preferably 200 μm or more and 4000 μm or less. Thereby, the flow path resistance of the vapor flow path can be sufficiently reduced, and the movement of the working fluid in the vapor flow path and the movement of the working fluid due to the action of the capillary force in the condensate flow path can be performed in good balance.

[0038] Regarding the liquid flow path groove 15a, the groove width indicated by F1 in FIGS. 8(a) and 8(b) is preferably 10 μm or more and 300 μm or less. Also, the depth of the groove indicated by G in FIG. 8(a) is preferably 5 μm or more and 200 μm or less. Thereby, the capillary force of the condensate flow path necessary for the movement of the condensate can be sufficiently exerted. Here, the depth G of the groove is preferably smaller than the remaining sheet thickness obtained by subtracting the depth G of the groove from the thickness of the first sheet 10. Thereby, it is possible to more surely prevent the sheet from being broken when the working fluid freezes. 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 F1 by G is preferably greater than 1.0 or less than 1.0. Among them, from the viewpoint of manufacturing, it is preferable that F1 is larger than G, and the aspect ratio is preferably greater than 1.3.

[0039] Regarding the wall 15b, the width indicated by F2 in FIGS. 8(a) and 8(b) is preferably 20 μm or more and 300 μm or less. If this width is less than 20 μm, it is likely to break due to repeated freezing and melting of the working fluid. If this width is greater than 300 μm, the width of the communication opening 15c becomes too large, and there is a possibility of hindering the smooth communication between the three condensate flow paths.

[0040] Regarding the communication opening 15c, the size of the opening along the direction in which the liquid flow path groove 15a indicated by F3 in FIG. 8(b) extends is preferably 20 μm or more and 180 μm or less. Also, the pitch of adjacent communication openings 15c in the direction in which the liquid flow path groove 15a indicated by F4 in FIG. 8(b) extends is preferably 300 μm or more and 2700 μm or less.

[0041] Also, in this embodiment, the cross-sectional shape of the liquid flow path groove 15a is semi-elliptical, but it is not limited thereto, and it may be a quadrangle such as a square, a rectangle, a trapezoid, a triangle, a semi-circle, a semi-elliptical bottom, a semi-circular bottom, or a combination thereof.

[0042] Next, the steam flow path groove 16 will be described. The steam flow path groove 16 is a part of the steam flow path 4 where the working fluid in the form of steam and condensate moves. The shape of the steam flow path groove 16 in plan view is shown in FIG. 3, and the cross-sectional shape of the steam flow path groove 16 is shown in FIG. 4.

[0043] As can be seen from these figures, the steam flow path groove 16 is constituted by a groove formed inside the ring of the outer peripheral liquid flow path portion 14 which is annular, among the inner surfaces 10a of the main body 11. Specifically, the steam flow path groove 16 of the present embodiment is a groove formed between adjacent inner liquid flow path portions 15 and between the outer peripheral liquid flow path portion 14 and the inner liquid flow path portion 15, and has a curved portion and extends. And a plurality (six in the present embodiment) of steam flow path grooves 16 are arranged in a direction different from the extending direction. Therefore, as can be seen from FIG. 4, the first sheet 10 has a shape in which the inner liquid flow path portion 15 is a convex stripe and the steam flow path groove 16 is a concave stripe, and the unevenness is repeated. Here, since the steam flow path groove 16 is a groove, in its cross-sectional shape, it includes a bottom portion and an opening existing at a portion on the opposite side facing the bottom portion.

[0044] The steam flow path groove 16 only needs to be configured such that when the steam flow path 4 is formed in combination with the steam flow path groove 26 of the second sheet 20, the working fluid moves in the steam flow path 4. Therefore, it is preferable that the steam flow path groove 16 further has the following configuration. In FIGS. 3 and 4, H 10 The width of the steam flow path groove 16 shown by is preferably formed to be larger than at least the widths C1 and F1 of the liquid flow path grooves 14a and 15a described above, and is preferably 100 μm or more and 2000 μm or less. On the other hand, in FIG. 4, I 10 The depth of the steam flow path groove 16 shown by is preferably formed to be larger than at least the depths D and G of the liquid flow path grooves 14a and 15a described above, and is preferably 10 μm or more and 300 μm or less. Thereby, when the steam flow path is formed, the working fluid moves stably, and by making the flow path cross-sectional area of the steam flow path groove larger than that of the liquid flow path groove, steam having a larger volume than the condensate can be smoothly moved due to the properties of the working fluid.

[0045] Here, as will be described later, when the steam flow path groove 16 is combined with the second sheet 20 to form the steam flow path 4, it is preferably configured such that the width of the steam flow path 4 is larger than the height (the size in the thickness direction), so that the aspect ratio represented by the value obtained by dividing H 10 by I 10 is preferably 4.0 or more, more preferably 8.0 or more.

[0046] In this embodiment, the cross-sectional shape of the steam flow path groove 16 is semi-elliptical, but it is not limited thereto, and it may be a quadrilateral such as a square, a rectangle, or a trapezoid, a triangle, a semi-circle, a circular bottom, a semi-elliptical bottom, or a combination thereof.

[0047] The steam flow path communication groove 17 is a groove that connects a plurality of steam flow path grooves 16 and forms a flow path that communicates with a plurality of steam flow paths 4 formed by the steam flow path grooves 16 at their ends in combination with the steam flow path communication groove 27 of the second sheet 20. Thereby, the movement of the working fluid generated in the steam flow path 4 in the direction in which the inner liquid flow path portion 15 extends can be smoothly performed. Also, thereby, the equalization of the working fluid in the steam flow path 4 can be achieved, the steam can be carried over a wider range, and the condensate flow path 3 formed by many liquid flow path grooves 14a and liquid flow path grooves 15a can be efficiently utilized.

[0048] As can be seen from FIGS. 2 and 3, the steam flow path communication groove 17 of this embodiment is formed between both ends in the direction in which the inner liquid flow path portion 15 extends, both ends in the direction in which the steam flow path groove 16 extends, and the outer peripheral liquid flow path portion 14. FIG. 5(b) shows a cross section orthogonal to the communication direction of the steam flow path communication groove 17. Note that since the boundary between the steam flow path communication groove 17 and the steam flow path groove 16 is not necessarily formed by a boundary based on the shape, the boundary is represented by a dotted line in FIGS. 2 and 3 for clarity.

[0049] The steam flow path communication groove 17 only needs to be able to connect adjacent steam flow path grooves 16, and its shape is not particularly limited. For example, it can have the following configuration. As shown by J in FIGS. 3 and 5(b), 10 the width of the steam flow path communication groove 17 is preferably 100 μm or more and 1000 μm or less. Also, as shown by K in FIG. 5(b), 10 the depth of the steam flow path communication groove 17 is preferably 10 μm or more and 300 μm or less, and among these, it is preferably the same as the depth I of the steam flow path groove 16. This facilitates manufacturing. 10

[0050] In this embodiment, the cross-sectional shape of the steam flow path communication groove 17 is semi-elliptical, but it is not limited to this, and it may be a quadrilateral such as a square, rectangle, trapezoid, a triangle, a semi-circle, a semi-circle at the bottom, a semi-ellipse at the bottom, or a combination thereof, etc.

[0051] Also, in this embodiment, the first sheet 10 includes a curved portion 18c at a portion where the extending directions of the liquid flow path groove 14a, the liquid flow path groove 15a, and the steam flow path groove 16 change. That is, the first sheet 10 includes a straight portion 18a where the liquid flow path groove 14a, the liquid flow path groove 15a, and the steam flow path groove 16 extend linearly in the x direction, a straight portion 18b where the liquid flow path groove 14a, the liquid flow path groove 15a, and the steam flow path groove 16 extend linearly in the y direction, and a curved portion 18c that connects the liquid flow path groove 14a, the liquid flow path groove 15a, and the steam flow path groove 16 in the straight portion 18a and the straight portion 18b. Therefore, one end of the curved portion 18c is connected to one straight portion 18a, the other end is connected to the other straight portion 18b, and the liquid flow path groove 14a, the liquid flow path groove 15a, and the steam flow path groove 16 are curved so that the flow direction changes from the x direction to the y direction and from the y direction to the x direction. Here, the boundary between the straight portion and the curved portion may be the point where the flow direction starts to change in each groove. The same can be considered hereinafter.

[0052] And, as can be seen from FIG. 3, in the curved portion 18c of this embodiment, the liquid flow path groove 14a, the liquid flow path groove 15a, and the steam flow path groove 16 are configured such that the radius of curvature of the outer steam flow path in the arrangement direction is larger than the radius of curvature of the inner steam flow path in the arrangement direction in the direction in which these flow path grooves are arranged. ​Here, when considering the curve as part of a circle or an ellipse, as shown in FIG. 3, the side towards the center of the circle or ellipse with respect to the curve is defined as the "inner side" of the curved portion, and the side opposite to the center side of the circle or ellipse with respect to the curve is defined as the "outer side" of the curved portion. Hereinafter, the shape of the curved portion can be considered in the same way. Also, for the radius of the curve, consider a circle passing through a total of three points: two points that are the boundaries between the straight portion and the curved portion, and one point at the center of the length of the groove in the curved portion, and define the radius of this circle as the radius of the curve. However, the shape of the curve is not limited to being part of a perfect circle, but can also be part of an ellipse, or a shape where some of the plurality of vapor flow path grooves arranged in the curved portion are straight. Hereinafter, the shape of the curved portion can be considered in the same way.

[0053] Among them, in this embodiment, these plurality of grooves are curved so as to draw concentric arcs. However, it is not limited to this, and the center position of the arc may be shifted. Furthermore, in the curved portion 18c, the radius of curvature is configured to be larger for the flow path grooves with longer lengths of each flow path groove.

[0054] In the vapor chamber, when a plurality of curved flow paths are arranged, the flow path length is shorter towards the inner side in the arrangement direction and longer towards the outer side in the arrangement direction. Therefore, the difference in flow resistance between the inner side and the outer side becomes large. This difference in flow resistance deteriorates the balance of the movement of the working fluid in the vapor chamber and is one of the reasons why sufficient heat transport capacity cannot be exhibited. On the other hand, by providing the curved portion 18c of this embodiment, it is possible to particularly relax the difference in flow resistance between the inner side and the outer side in the vapor flow path groove 16. As a result, the balance of the movement of the working fluid is improved, and the heat transport capacity can also be increased.

[0055] Further, in the curved portion 18c, with respect to the communication openings 14c and 15c provided in the walls 14b and 15b that partition the liquid flow path groove 14a and the liquid flow path groove 15c from the vapor flow path groove 16 (see FIGS. 6 and 8(b)), the pitch thereof can be configured to be different from that of other portions (the straight portions 18a and 18b). The pitch of the communication openings in the curved portion may be made larger or smaller than the pitch of the communication openings in the straight portion. Which form to adopt can be comprehensively determined and adopted by considering the influence of the overall shape of the vapor chamber, the position of the heat source, etc., and selecting a form that can reduce the flow resistance. Alternatively, for this curved portion 18c, the communication openings 14c and 15c may not be provided. In a form where the pitch of the communication openings in the curved portion is made larger than the pitch of the communication openings in the straight portion, the working fluid flowing through the vapor flow path groove 16 (vapor flow path 4) is suppressed from entering the communication openings 14c and 15c in the curved portion 18c. In the curved portion 18c, since a force acts on the working fluid moving in the vapor flow path groove 16 (vapor flow path 4) to directly flow into the communication openings 14c and 15c due to its flow, there is a tendency for the vapor to enter the condensate flow path 3 and for the flow resistance to increase due to the unevenness of the communication openings 14c and 15c. On the other hand, by increasing the pitch of the communication openings 14c and 15c or eliminating the communication openings in the curved portion 18c, such an increase in flow resistance can be suppressed, the difference in flow resistance for each vapor flow path groove 16 (vapor flow path 4) can be further reduced, the balance of the movement of the working fluid can be improved, and the heat transport capacity may be increased. On the other hand, in a form where the pitch of the communication openings in the curved portion is made smaller than the pitch of the communication openings in the straight portion, in the curved portion, the chance that the vapor flowing through the vapor flow path grooves (vapor flow path) strongly hits the wall surface increases, so there is a tendency to condense easily. At this time, by forming the pitch of the communication openings in the curved portion to be smaller than the pitch of the communication openings in the straight portion, the number of communication openings can be increased, and the condensed liquid can be smoothly introduced into the liquid flow path grooves (condensed liquid flow path), and it is possible to suppress the vapor flow path from being blocked by the condensed liquid. As a result, an increase in flow resistance can be suppressed, the difference in flow resistance for each vapor flow path groove (vapor flow path) can be further reduced, the balance of the movement of the working fluid can be improved, and the heat transport capacity may be increased.

[0056] Also, in the curved portion 18c, the widths of the plurality of vapor flow path grooves 16 may be changed for each flow path groove. Specifically, the groove width of the vapor flow path groove with a large radius of curvature may be made larger than the groove width of the vapor flow path groove with a small radius of curvature. Thereby, the flow resistance of the vapor flow path with a large radius of curvature, where the movement distance of the vapor is long, can be reduced. Also, the groove width of the vapor flow path groove with a small radius of curvature may be made larger than the groove width of the vapor flow path groove with a large radius of curvature. Thereby, the flow resistance of the vapor flow path in the curved portion due to the small radius can be reduced. Furthermore, for the vapor flow path arranged at the center, the groove widths of the vapor flow path groove with a large radius and the vapor flow path groove with a small radius may be made larger. Also, instead of or in combination with the width of the vapor flow path groove, the depth of the vapor flow path groove may be changed for each flow path so as to achieve the same effect. When adjusting by changing the depth direction of the above flow path groove, spreading in the plane (xy plane) direction is suppressed, many parts for arranging the condensed liquid flow path can be secured to improve the heat transport capacity, or a wide outer peripheral joint portion can be taken to improve the pressure resistance reliability. By means as described above, it is further possible to reduce the difference in flow resistance between the plurality of vapor flow path grooves, improve the balance of the movement of the working fluid, and increase the heat transport capacity.

[0057] Further, in the bent portion 18c, at least one of the width and depth of the vapor flow path groove 16 may be increased with respect to the straight portion 18a and the straight portion 18b. According to this, the flow resistance in the bent portion 18c where the flow resistance is large can be reduced, and the flow resistance of the entire vapor chamber becomes small, so that the movement of the working fluid becomes smoother and the heat transport capacity can be enhanced.

[0058] Next, the second sheet 20 will be described. In this embodiment, the second sheet 20 is also a sheet-like member as a whole, and is bent in an L shape in plan view. FIG. 9 shows a perspective view of the second sheet 20 as viewed from the inner surface 20a side, and FIG. 10 shows a plan view of the second sheet 20 as viewed from the inner surface 20a side. Further, FIG. 11 shows a cross-sectional view of the second sheet 20 when cut along XI-XI in FIG. 10. Also, FIG. 12 shows a cross-sectional view of the second sheet 20 when cut along XII-XII in FIG. 10. The second sheet 20 includes an inner surface 20a, an outer surface 20b on the side opposite to the inner surface 20a, and a side surface 20c that forms a thickness across the inner surface 20a and the outer surface 20b. A pattern for the movement of the working fluid is formed on the inner surface 20a side. As will be described later, the inner surface 20a of the second sheet 20 and the inner surface 10a of the first sheet 10 described above are overlapped and joined so as to face each other, thereby forming a hollow portion, and the working fluid is sealed therein to form a sealed space 2.

[0059] The thickness of the second sheet 20 is not particularly limited, but is preferably 0.01 mm or more and 1.0 mm or less, and more preferably 0.05 mm or more and 0.2 mm or less. Thereby, the number of scenarios where it can be applied as a thin vapor chamber can be increased.

[0060] The second sheet 20 includes a main body 21 and an injection portion 22. The main body 21 is sheet-like and forms a portion where the working fluid moves. In this embodiment, it is L-shaped with a bent portion in plan view. The injection part 22 is a part for injecting the working fluid into the hollow part formed by the first sheet 10 and the second sheet 20, and in this embodiment, it is in the shape of a quadrangular sheet in plan view protruding from the L-shaped in plan view of the main body 21. In this embodiment, an injection groove 22a is formed on the inner surface 20a side of the injection part 22 of the second sheet 20, and it communicates from the side surface 20c of the second sheet 20 to the inside of the main body 21 (the part to be the hollow part and the sealed space 2).

[0061] On the inner surface 20a side of the main body 21, a structure for the working fluid to move is formed. Specifically, on the inner surface 20a side of the main body 21, an outer peripheral joint part 23, an outer peripheral liquid flow path part 24, an inner liquid flow path part 25, a vapor flow path groove 26, and a vapor flow path communication groove 27 are provided.

[0062] The outer peripheral joint part 23 is a surface formed along the outer periphery of the main body 21 on the inner surface 20a side of the main body 21. By overlapping and joining (such as diffusion bonding or brazing) this outer peripheral joint part 23 with the outer peripheral joint part 13 of the first sheet 10, a hollow part is formed between the first sheet 10 and the second sheet 20, and the working fluid is sealed therein to become the sealed space 2. In FIGS. 10, 11, and 12, A 20 The width of the outer peripheral joint part 23 shown in is preferably the same as the width A 10 of the outer peripheral joint part 13 of the main body 11 described above.

[0063] The outer peripheral liquid flow path part 24 functions as a liquid flow path part and is a part constituting a part of the condensate flow path 3 (see, for example, FIG. 14), which is a flow path through which the working fluid passes when it condenses and liquefies.

[0064] The outer peripheral liquid flow path portion 24 is formed along the inner side of the outer peripheral joint portion 23 on the inner surface 20a of the main body 21, and is formed in an annular shape along the outer periphery of the sealed space 2. In this embodiment, the outer peripheral liquid flow path portion 24 of the second sheet 20 is a flat surface and flush with the outer peripheral joint portion 23 before being joined to the first sheet 10, as can be seen from FIGS. 11 and 12. Thereby, the openings of at least some of the plurality of liquid flow path grooves 14a of the first sheet 10 described above are closed to form the condensate flow path 3. The detailed aspects regarding the combination of the first sheet 10 and the second sheet 20 will be described later. Note that, since the outer peripheral joint portion 23 and the outer peripheral liquid flow path portion 24 are flush with each other in the second sheet 20 in this way, there is no structural boundary line for distinguishing between the two. However, for the sake of clarity, FIGS. 9 and 10 show the boundary between the two by a dotted line.

[0065] The outer peripheral liquid flow path portion 24 preferably has the following configuration. The width B of the outer peripheral liquid flow path portion 24 shown in FIGS. 10, 11, and 12 20 is not particularly limited, and may be the same as or different from the width B of the outer peripheral liquid flow path portion 14 of the first sheet 10. In this embodiment, the width B 10 is the same as the width B 10 and the width B 20 . Width B 20 When made smaller than width B 10 , in at least a part of the outer peripheral liquid flow path portion 14, the openings of the liquid flow path grooves 14a are not closed by the outer peripheral liquid flow path portion 24 and are open, from which condensate easily enters and vapor easily exits, so that smoother movement of the working fluid can be achieved.

[0066] In this embodiment, the outer peripheral liquid flow path portion 24 of the second sheet 20 is configured to be a flat surface, but is not limited thereto, and liquid flow path grooves may be provided in the same manner as the outer peripheral liquid flow path portion 14. In this case, the condensate flow path 3 can be formed by overlapping the liquid flow path grooves of the first sheet and the liquid flow path grooves of the second sheet.

[0067] Also, in this embodiment, as described in the first sheet as well, the outer peripheral liquid flow path portion 24 does not necessarily have to be provided, and a form in which the outer peripheral liquid flow path portion 24 is not provided may also be acceptable.

[0068] Next, the inner liquid flow path portion 25 will be described. The inner liquid flow path portion 25 is also a liquid flow path portion and is one part that constitutes the condensate flow path 3.

[0069] As can be seen from FIGS. 9 to 12, the inner liquid flow path portion 25 is formed inside the ring of the annular outer peripheral liquid flow path portion 24 on the inner surface 20a of the main body 21. The inner liquid flow path portion 25 of this embodiment is a rib that extends with a curved portion, and a plurality (five in this embodiment) of inner liquid flow path portions 25 are arranged with intervals in a direction different from the extending direction, and are arranged between the vapor flow path grooves 26. In this embodiment, each inner liquid flow path portion 25 is formed such that the surface on the inner surface 20a side becomes a flat surface before joining with the first sheet 10. Thereby, at least a part of the liquid flow path grooves 15a of the plurality of liquid flow path grooves 15a of the first sheet 10 described above are closed to form the condensate flow path 3. In addition, when the groove for forming the condensate flow path 3 is not formed in the inner liquid flow path portion 25 as in this embodiment, the thickness of the second sheet 20 is preferably equal to or greater than the thickness obtained by subtracting the depth G (see FIG. 8(a)) of the liquid flow path groove 15a from the thickness of the first sheet 10. Thereby, breakage (tearing) on the second sheet side in the vapor chamber can be prevented.

[0070] In this embodiment, the inner liquid flow path portion 25 of the second sheet 20 is configured to be composed of a flat surface, but it is not limited thereto, and liquid flow path grooves may be provided in the same manner as the inner liquid flow path portion 15. At this time, the condensate flow path 3 can be formed by overlapping the liquid flow path grooves of the first sheet and the liquid flow path grooves of the second sheet.

[0071] The width E of the inner liquid flow path portion 25 shown in FIGS. 10 and 11 20 is not particularly limited, and may be the same as or different from the width E 10 of the inner liquid flow path portion 15 of the first sheet 10. In this embodiment, the width E 10and width E 20 is the same as that. Width E 20 and width E 10 are different, which can reduce the influence of misalignment during joining. Note that width E 20 is made smaller than width E 10 In this case, in at least a part of the inner liquid flow path portion 15, the opening of the liquid flow path groove 15a is not closed by the inner liquid flow path portion 25 and is open, from which condensate easily enters and the generated vapor easily exits. Therefore, the working fluid can be moved more smoothly.

[0072] Next, the vapor flow path groove 26 will be described. The vapor flow path groove 26 is a part where the working fluid in vapor and condensate states moves and constitutes a part of the vapor flow path 4. The shape of the vapor flow path groove 26 in plan view is shown in FIG. 10, and the cross-sectional shape of the vapor flow path groove 26 is shown in FIG. 11.

[0073] As can be seen from these figures, the vapor flow path groove 26 is composed of a groove having a curved portion formed inside the ring of the outer peripheral liquid flow path portion 24 which is annular on the inner surface 20a of the main body 21. Specifically, the vapor flow path groove 26 of this embodiment is a groove formed between adjacent inner liquid flow path portions 25 and between the outer peripheral liquid flow path portion 24 and the inner liquid flow path portion 25. And a plurality (six in this embodiment) of vapor flow path grooves 26 are arranged in a direction different from the direction in which the vapor flow path groove 26 extends. Therefore, as can be seen from FIG. 10, the second sheet 20 has convex ridges with the inner liquid flow path portion 25 as convex and concave ridges with the vapor flow path groove 26 as concave, and has a shape in which these irregularities are repeated. Here, since the vapor flow path groove 26 is a groove, in its cross-sectional shape, it includes a bottom portion and an opening existing at a portion on the opposite side facing the bottom portion.

[0074] The vapor flow path groove 26 is preferably arranged at a position overlapping with the vapor flow path groove 16 of the first sheet 10 in the thickness direction when combined with the first sheet 10. Thereby, the vapor flow path 4 can be formed by the vapor flow path groove 16 and the vapor flow path groove 26. In FIGS. 10 and 11, H 20The width of the steam flow path groove 26 shown in is not particularly limited, and may be the same as or different from the width H of the steam flow path groove 16 of the first sheet 10. In this embodiment, the width H 10 is the same as the width H 10 and the width H 20 are the same. The width H 20 and the width H 10 If they are different, the influence of misalignment during joining can be reduced. Note that if the width H 20 is made larger than the width H 10 in at least a part of the inner liquid flow path portion 15, the opening of the liquid flow path groove 15a is not closed by the inner liquid flow path portion 25 and is open, and condensate can easily enter and steam can easily exit from here. Therefore, smoother movement of the working fluid can be achieved. On the other hand, the depth of the steam flow path groove 26 shown in I 20 in FIG. 11 is preferably 10 μm or more and 300 μm or less.

[0075] Here, as will be described later, when the steam flow path groove 26 is combined with the first sheet 10 to form the steam flow path 4, it is preferably configured such that the width of the steam flow path 4 is larger than the height (size in the thickness direction), resulting in a flat shape. Therefore, the aspect ratio represented by the value obtained by dividing H 20 by I 20 is preferably 4.0 or more, more preferably 8.0 or more.

[0076] In this embodiment, the cross-sectional shape of the steam flow path groove 26 is semi-elliptical, but it may also be a quadrilateral such as a square, rectangle, trapezoid, triangle, semi-circle, a shape with a semi-circular bottom, a semi-elliptical bottom, or a combination thereof.

[0077] The steam flow path communication groove 27 is a groove that, in combination with the steam flow path communication groove 17 of the first sheet 10, forms a flow path that communicates the ends of the plurality of steam flow paths 4 formed by the steam flow path grooves 26. As a result, the movement of the working fluid generated in the steam flow path 4 in the direction in which the inner liquid flow path portion 25 extends is carried out in a well-balanced manner. In addition, the equalization of the working fluid in the steam flow path 4 is achieved, the steam is carried over a wider range, and many condensate flow paths 3 can be efficiently utilized, so that the movement of the working fluid can be made smoother.

[0078] As can be seen from FIGS. 10 and 12, the steam flow path communication groove 27 of this embodiment is formed between both end portions in the direction in which the inner liquid flow path portion 25 extends, both end portions in the direction in which the steam flow path groove 26 extends, and the outer peripheral liquid flow path portion 24. In addition, FIG. 12 shows a cross section orthogonal to the communication direction of the steam flow path communication groove 27.

[0079] In FIGS. 10 and 12, J 20 The width of the steam flow path communication groove 27 shown is not particularly limited, and may be the same as the width J 10 of the steam flow path communication groove 17 of the first sheet 10, or may be different from the width J 10 . Note that when the width J 20 is made larger than the width J 10 , in at least a part of the outer peripheral liquid flow path portion 14 of the first sheet 10, the opening of the liquid flow path groove 14a is arranged so as to form a part of the steam flow path 4, so that the condensate easily enters and the generated steam easily exits, and the working fluid can be moved more smoothly.

[0080] The width J 20 is preferably in the range of 100 μm or more and 1000 μm or less, and the depth of the steam flow path communication groove 27 shown by K 20 in FIG. 12 is preferably 10 μm or more and 300 μm or less.

[0081] In this embodiment, the cross-sectional shape of the steam flow path communication groove 27 is semi-elliptical, but it is not limited thereto, and may be a quadrangle such as a square, a rectangle, a trapezoid, a triangle, a semi-circle, a semi-elliptical bottom, a semi-circular bottom, or a combination thereof.

[0082] Further, in the present embodiment, the second sheet 20 includes a curved portion 28c at a portion where the extending direction of the outer liquid flow path portion 24, the inner liquid flow path portion 25, and the vapor flow path groove 26 changes. That is, as can be seen from FIG. 10, the second sheet 20 includes a straight portion 28a where the outer liquid flow path portion 24, the inner liquid flow path portion 25, and the vapor flow path groove 26 extend linearly in the x direction, a straight portion 28b where the outer liquid flow path portion 24, the inner liquid flow path portion 25, and the vapor flow path groove 26 extend linearly in the y direction, and a curved portion 28c that connects the outer liquid flow path portion 24, the inner liquid flow path portion 25, and the vapor flow path groove 26 in the straight portion 28a and the straight portion 28b. Accordingly, one end of the curved portion 28c is connected to one straight portion 28a, the other end is connected to the other straight portion 28b, and the outer liquid flow path portion 24, the inner liquid flow path portion 25, and the vapor flow path groove 26 are curved so that the flow direction changes from the x direction to the y direction and from the y direction to the x direction.

[0083] As can be seen from FIG. 10, in the curved portion 28c of the present embodiment, the outer liquid flow path portion 24, the inner liquid flow path portion 25, and the vapor flow path groove 26 extend so as to curve such that the radius of curvature increases from the inside to the outside in the direction in which they are arranged.

[0084] The outer liquid flow path portion 24, the inner liquid flow path portion 25, and the vapor flow path groove 26 in the curved portion 28c can be considered in the same manner as the curved portion 18c of the first sheet 10 described above.

[0085] Next, the structure when the first sheet 10 and the second sheet 20 are combined to form the vapor chamber 1 will be described. Through this description, the arrangement, size, shape, etc. of each component of the first sheet 10 and the second sheet 20 will be further understood. FIG. 13 shows a cross-section obtained by cutting the vapor chamber 1 in the thickness direction along the y direction indicated by XIII-XIII in FIG. 1(a). This figure shows a cross-section of the vapor chamber 1 at this portion, which is a combination of the figure shown in FIG. 4 of the first sheet 10 and the figure shown in FIG. 11 of the second sheet 20. FIG. 14 shows an enlarged view of the portion indicated by XIV in FIG. 13. FIG. 15 shows a cross-sectional view taken along the thickness direction of the vapor chamber 1 along the x direction indicated by XV-XV in FIG. 1(a). This figure is a combination of the figure shown in FIG. 5(b) in the first sheet 10 and the figure shown in FIG. 12 in the second sheet 20, and represents the cross-sectional view of the vapor chamber 1 at this portion.

[0086] As can be seen from FIGS. 1(a), 1(b), and FIGS. 13 to 15, the first sheet 10 and the second sheet 20 are arranged and joined so as to be overlapped to form the vapor chamber 1. At this time, the inner surface 10a of the first sheet 10 and the inner surface 20a of the second sheet 20 are arranged to face each other, the main body 11 of the first sheet 10 and the main body 21 of the second sheet overlap, and the injection part 12 of the first sheet 10 and the injection part 22 of the second sheet 20 overlap.

[0087] With such a laminate of the first sheet 10 and the second sheet 20, each component provided in the main body 11 and the main body 21 is arranged so as to appear in FIGS. 13 to 15. Specifically, it is as follows.

[0088] The vapor chamber 1 of this embodiment has a particularly large effect when it is thin. From this viewpoint, the thickness of the vapor chamber 1 indicated by L0 in FIGS. 1 and 13 is 1 mm or less, more preferably 0.4 mm or less, and even more preferably 0.2 mm or less. By setting it to 0.4 mm or less, in an electronic device in which the vapor chamber 1 is installed, it is often possible to install the vapor chamber inside the electronic device without performing processing (such as groove formation etc.) for forming a space for arranging the vapor chamber. And according to this embodiment, even such a thin vapor chamber can maintain high thermal performance while being strong and resistant to deformation.

[0089] On one hand, the outer peripheral joint portion 13 of the first sheet 10 and the outer peripheral joint portion 23 of the second sheet 20 are arranged so as to overlap each other, and the two are joined by joining means such as diffusion bonding or brazing. Thereby, a sealed space 2 is formed between the first sheet 10 and the second sheet 20.

[0090] The outer peripheral liquid flow path portion 14 of the first sheet 10 and the outer peripheral liquid flow path portion 24 of the second sheet 20 are arranged so as to overlap each other. Thereby, a condensate flow path 3 is formed through which condensate in a state where the working fluid has condensed and liquefied flows in the liquid flow path groove 14a of the outer peripheral liquid flow path portion 14 and the outer peripheral liquid flow path portion 24. Similarly, the inner liquid flow path portion 15 which is a rib of the first sheet 10 and the inner liquid flow path portion 25 which is a rib of the second sheet 20 are arranged so as to overlap each other. Thereby, a condensate flow path 3 through which condensate flows is formed by the liquid flow path groove 15a of the inner liquid flow path portion 15 and the inner liquid flow path portion 25.

[0091] Here, it is preferable that the cross-sectional shape of the condensate flow path 3 is a flat shape as the vapor chamber 1 is thinned. Thereby, the capillary force can be increased, and the movement of the condensate can be made smoother, so that the heat transport capacity can be maintained at a high level. More specifically, it is preferable that the ratio represented by the value obtained by dividing the width of the condensate flow path 3 by the height is greater than 1.0 and less than or equal to 4.0. At this time, the width of the condensate flow path 3 preferably conforms to the width F1 of the liquid flow path groove 15a in this embodiment and is 10 μm or more and 300 μm or less. If the width is less than 10 μm, the flow path resistance increases and there is a risk that the transport capacity will decrease. On the other hand, if the width is greater than 300 μm, the capillary force decreases, so there is a risk that the transport capacity will decrease. In addition, the height of the condensate flow path 3 preferably conforms to the depth G of the liquid flow path groove 15a in this embodiment and is 5 μm or more and 200 μm or less. Thereby, the capillary force of the condensate flow path required for movement can be sufficiently exerted. In addition, this height is preferably equal to or less than the thicknesses (wall thicknesses) of the first sheet 10 and the second sheet 20 on one side and the other side in the thickness direction (z direction) with the condensate flow path 3 interposed therebetween. Thereby, breakage (tearing) of the vapor chamber due to the condensate flow path 3 can be further prevented.

[0092] In this embodiment, the cross-sectional shape of the condensate flow path 3 is semi-elliptical due to the cross-sectional shapes of the liquid flow path groove 14a and the liquid flow path groove 15, but it is not limited thereto, and may be a quadrilateral such as a square, a rectangle, or a trapezoid, a triangle, a semi-circle, a semi-circular bottom, a semi-elliptical bottom, or a combination thereof. Further, it can be crescent-shaped.

[0093] In this embodiment, since the liquid flow path grooves 14a and 15a are provided only in the first sheet 10, the height of the condensate flow path is based on the depths of the liquid flow path grooves 14a and 15a, but it is not limited thereto, and liquid flow path grooves may also be provided in the second sheet 20. In this case, the condensate flow path is formed by overlapping the liquid flow path grooves of the first sheet and the liquid flow path grooves of the second sheet, and the height of the condensate flow path conforms to the sum of the depths of both liquid flow path grooves.

[0094] When the condensate flow path is formed by providing liquid flow path grooves in the first sheet and the second sheet and overlapping them in this way, the condensate flow path can be configured as shown in FIGS. 16(a) to 16(c). The example of FIG. 16(a) is an example in which the liquid flow path grooves of the first sheet and the second sheet are arranged with the same width and at the same position. The example of FIG. 16(b) is an example in which the width of the liquid flow path groove in the second sheet is made larger than the width of the liquid flow path groove in the first sheet and the positions are the same. In this example, a convex portion is formed in the condensate flow path as indicated by P, the capillary force can be improved, and the force for moving the condensate (the supply force of the condensate) can be increased. The example of FIG. 16(c) is an example where the liquid flow path grooves of the first sheet and the second sheet have the same width but are offset in position. Also in this example, convex portions are formed in the condensate flow path as indicated by P, improving the capillary force and enhancing the force for moving the condensate (the supply force of the condensate).

[0095] Further, as described above, communication openings 14c and 15c are formed in the condensate flow path 3. As a result, a plurality of condensate flow paths 3 communicate with each other, achieving equalization of the condensate and enabling efficient movement of the condensate. Also, regarding the communication openings 14c and 15c that are adjacent to the vapor flow path 4 and communicate the vapor flow path 4 and the condensate flow path 3, the condensate generated in the vapor flow path 4 can be smoothly moved to the condensate flow path 3, and the vapor generated in the condensate flow path 3 can be smoothly moved to the vapor flow path 4, allowing the movement of the working fluid to be performed promptly.

[0096] Also, the condensate flow path 3 formed by the outer peripheral liquid flow path portion 14 and the outer peripheral liquid flow path portion 24 is preferably formed continuously and annularly along the edge in the sealed space 2. That is, it is preferable that the condensate flow path 3 formed by the outer peripheral liquid flow path portion 14 and the outer peripheral liquid flow path portion 24 extends in an annular shape over one circumference without being interrupted by other components. Thereby, factors that impede the movement of the condensate can be reduced, and the condensate can be moved smoothly. However, the outer peripheral liquid flow path portion does not necessarily have to be provided, and from the viewpoints of the shape of the vapor chamber, the relationship between the vapor chamber and the device to which it is applied, and the usage environment, etc., a form in which the outer peripheral liquid flow path portion 14 is not provided may also be adopted. In this form, the outer peripheral portion can be configured as a vapor flow path so that heat can be carried by vapor to the outer peripheral portion of the vapor chamber, and further heat equalization may be achievable.

[0097] The openings of the vapor flow path grooves 16 of the first sheet 10 and the openings of the vapor flow path grooves 26 of the second sheet 20 overlap so as to face each other to form a flow path, which becomes the vapor flow path 4. Here, as the vapor flow path 4 is thinned along with the thinning of the vapor chamber 1, it is preferable that its cross-sectional shape is a flat shape. This enables the surface area inside the flow path to be secured even when thinned, and the heat transport capacity can be maintained at a high level. More specifically, the width W of the vapor flow path 4 shown in FIG. 14 B , the height H B wherein, it is preferable that the ratio represented by the value obtained by dividing W B by H B is 2.0 or more. From the viewpoint of ensuring an even higher heat transport capacity, the ratio is more preferably 4.0 or more.

[0098] As can be seen from FIG. 15, overlapping the openings of the vapor flow path communication grooves 17 of the first sheet 10 and the openings of the vapor flow path communication grooves 27 of the second sheet 20 so that they face each other to form an overlapping flow path, a plurality of vapor flow paths 4 formed by the vapor flow path grooves 16 and the vapor flow path grooves 26 communicate with each other at their ends, serving as a flow path for the balanced movement of the working fluid.

[0099] As described above, in the sealed space 2 of the vapor chamber 1, the condensate flow path 3 and the vapor flow path 4 are formed according to the shapes of the first sheet 10 and the second sheet. FIG. 17 shows a view focusing on the condensate flow path 3 and the vapor flow path formed in the sealed space 2. As can be seen from FIG. 14, FIG. 17, etc., the vapor chamber 1 has a shape in which a plurality of condensate flow paths 3 are arranged between two vapor flow paths 4. This results in a form in which the condensate flow path 3 through which the condensate mainly flows and the vapor flow path 4 through which the vapor and condensate move are separated and arranged alternately, facilitating the smooth movement of the working fluid.

[0100] In the vapor flow path 4 and the condensate flow path 3, the working fluid in the state of vapor and condensate moves in the vapor flow path 4, and heat transfer and diffusion are efficiently carried out. On the other hand, the capillary force enables the condensate to move efficiently in the condensate flow path 3 provided separately from the vapor flow path 4, making it possible to suppress the occurrence of dry-out.

[0101] In the vapor chamber 1, two straight portions 6 in which the directions in which the condensate flow path 3 and the vapor flow path 4 extend are different are connected by a curved portion 7. By forming such a flow path, when the vapor chamber is arranged in an electronic device, even when it is subject to restrictions on the arrangement and a straight-line-only flow path cannot be formed, the heat generated from the heat source can be efficiently moved to a separated position by providing the curved portion 7.

[0102] This curved portion 7 is formed by the curved portion 18c of the first sheet 10 and the curved portion 28c of the second sheet 20. Therefore, one end of the curved portion 7 is connected to one straight portion 6, the other end is connected to the other straight portion 6, and the condensate flow path 3 and the vapor flow path 4 are curved so that the flow direction changes from the x direction to the y direction and from the y direction to the x direction.

[0103] As can be seen from FIG. 17, in the curved portion 7 of the present embodiment, the condensate flow path 3 and the vapor flow path 4 are configured such that the radius of curvature of the outer flow path in the arrangement direction is larger than the radius of curvature of the inner flow path in the arrangement direction in the direction in which these flow paths are arranged. In this embodiment, among others, these plurality of flow paths are curved so as to draw concentric arcs. However, it is not limited to this, and the centers of the arcs may not be the same. Furthermore, in this embodiment, in the curved portion 7, the long flow path has a large radius, and the short flow path has a small radius.

[0104] In the vapor chamber, when a plurality of curved flow paths are arranged, the flow path length is shorter toward the inner side in the arrangement direction and longer toward the outer side in the arrangement direction. Therefore, the difference in flow resistance between the inner side and the outer side becomes large. This difference in flow resistance deteriorates the balance of the movement of the working fluid in the vapor chamber and is one of the reasons why sufficient heat transport capacity cannot be exhibited. On the other hand, by providing the curved portion 7 of the present embodiment, it is possible to alleviate the difference in flow resistance between the inner side and the outer side, particularly in the vapor flow path 4. As a result, the balance of the movement of the working fluid is improved, and the heat transport capacity can also be increased.

[0105] Also, in the bent portion 7, the communication openings 14c and 15c (see FIGS. 6 and 8(b)) provided in the wall partitioning the condensate flow path 3 and the vapor flow path 4 belonging to the bent portion 7 can be configured differently from other portions (the straight portion 6). For this, the pitch of the communication openings in the bent portion may be made larger or smaller than the pitch of the communication openings in the straight portion. Which form to adopt can be comprehensively determined and adopted by considering the influence of the overall shape of the vapor chamber, the position of the heat source, etc., and selecting a form that can reduce the flow resistance. Or, for this bent portion 7, the communication openings 14c and 15c may not be provided. In a form where the pitch of the communication openings in the bent portion is made larger than the pitch of the communication openings in the straight portion, it is possible to prevent the working fluid flowing through the vapor flow path from entering the communication openings in the bent portion. In the bent portion, since the force that the working fluid moving through the vapor flow path directly flows into the communication openings due to its flow acts, there is a tendency for the vapor to enter the condensate flow path and for the flow resistance to increase due to the unevenness of the communication openings. In contrast, by increasing the pitch of the communication openings in the bent portion or eliminating the openings, such an increase in flow resistance can be suppressed, the difference in flow resistance for each vapor flow path can be further reduced, the balance of the movement of the working fluid can be improved, and the heat transport capacity can be increased in some cases. On the other hand, in a form where the pitch of the communication openings in the bent portion is made smaller than the pitch of the communication openings in the straight portion, since the opportunity for the vapor flowing through the vapor flow path to strongly hit the wall surface increases in the bent portion, it tends to condense easily. At this time, by adopting a form where the pitch of the communication openings in the bent portion is smaller than the pitch of the communication openings in the straight portion, the number of communication openings can be increased, the condensate can be smoothly introduced into the condensate flow path, and it is possible to suppress the vapor flow path from being blocked by the condensate. Thereby, an increase in flow resistance can be suppressed, the difference in flow resistance for each vapor flow path can be further reduced, the balance of the movement of the working fluid can be improved, and the heat transport capacity can be increased in some cases.

[0106] Further, in the bent portion 7, the flow path cross-sectional area of the plurality of vapor flow paths 4 may be changed for each flow path. Specifically, the flow path cross-sectional area of the vapor flow path having a larger radius of curvature may be increased with respect to the flow path cross-sectional area of the vapor flow path having a smaller radius of curvature. Thereby, the flow resistance of the vapor flow path having a longer vapor movement distance and a larger radius of curvature can be reduced. For this purpose, the width of the vapor flow path or the height of the vapor flow path can be changed. Conversely, the flow path cross-sectional area of the vapor flow path having a smaller radius of curvature may be increased with respect to the flow path cross-sectional area of the vapor flow path having a larger radius of curvature. Thereby, the flow resistance of the bent portion due to the smaller radius can be reduced. For this purpose, the width of the vapor flow path or the height of the vapor flow path can be changed. Furthermore, with respect to the central vapor flow path, the flow path cross-sectional areas of the vapor flow paths having a large radius and a small radius may be increased. Here, the "flow path cross-sectional area" is the cross-sectional area of the flow path on a plane orthogonal to the direction in which the flow path extends. By means as described above, it is possible to reduce the difference in flow resistance between the plurality of vapor flow paths, improve the balance of the movement of the working fluid, and enhance the heat transport capacity.

[0107] Also, in the bent portion 7, the flow path cross-sectional area of the vapor flow path 4 may be increased with respect to the straight portion 6. According to this, the flow resistance in the bent portion 7, which has a larger flow resistance in shape than the straight portion 6, can be reduced, and the flow resistance of the entire vapor chamber becomes smaller, so that the movement of the working fluid becomes smoother and the heat transport capacity can be enhanced.

[0108] On the other hand, as also shown in FIG. 1 for the injection portions 12 and 22, their inner surfaces 10a and 20a overlap so as to face each other, and the opening on the side opposite to the bottom of the injection groove 22a of the second sheet 20 is blocked by the inner surface 10a of the injection portion 12 of the first sheet 10, and an injection flow path 5 is formed that communicates with the hollow portion (condensate flow path 3 and vapor flow path 4) between the outside and the main bodies 11 and 21. However, after injecting the working fluid into the hollow portion from the injection channel 5, the injection channel 5 is closed to form a sealed space 2. Therefore, in the final form of the vapor chamber 1, the sealed space 2 does not communicate with the outside.

[0109] And 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 working fluids commonly used in normal vapor chambers, such as pure water, ethanol, methanol, acetone, etc., can be used.

[0110] The vapor chamber as described above can be manufactured, for example, as follows.

[0111] Prepare a sheet made of the material constituting the first sheet 10 and having the outer peripheral shape of the first sheet 10, and a sheet made of the material constituting the second sheet 20 and having the outer peripheral shape of the second sheet 20. The liquid flow channel grooves 14a, liquid flow channel grooves 15a, vapor flow channel grooves 16, vapor flow channel grooves 26, vapor flow channel communication grooves 17, and vapor flow channel communication grooves 27 described above are formed on these sheets by half etching. Here, half etching means removing the material by etching to the middle of the thickness direction without penetrating the thickness direction by etching to form grooves and depressions.

[0112] Next, the etched sheet having the shape of the first sheet 10 and the etched sheet having the shape of the second sheet 20 are overlapped with their inner surfaces 10a and 20a facing each other and temporarily fixed. The method of temporary fixing is not particularly limited, and examples include resistance welding, ultrasonic welding, and adhesion with an adhesive. After temporary fixing, diffusion bonding is performed to permanently bond these sheets. Note that instead of diffusion bonding, brazing may be used for bonding. However, in the case of a vapor chamber as thin as in this embodiment, since the condensate flow path and the vapor flow path provided therein are narrow, when brazing is used, there is a risk that the brazing material may enter these flow paths. And since a strong capillary force acts on the flow paths as described above, there is also a risk that the brazing material may spread over a wide range of the flow paths. From such a viewpoint, welding such as diffusion bonding or ultrasonic bonding that does not cause such problems is preferable.

[0113] After bonding, evacuation is performed from the formed injection flow path 5 to reduce the pressure inside the hollow portion. Then, the working fluid is injected from the injection flow path 5 into the depressurized hollow portion so that the working fluid is put into the hollow portion 2. Then, the injection flow path 5 is closed by using laser melting or caulking on the injection portions 12 and 22. As a result, a sealed space 2 is formed, and the working fluid is stably held inside thereof to become the vapor chamber 1.

[0114] Next, the operation when the vapor chamber 1 operates will be described. FIG. 18 schematically shows a state in which the vapor chamber 1 is disposed inside a portable terminal 40 which is one form of an electronic device. Here, since the vapor chamber 1 is disposed inside the housing 41 of the portable terminal 40, it is represented by a dotted line. Such a portable terminal 40 includes a housing 41 that houses various electronic components, and a display unit 42 that is exposed to the outside so that an image can be seen through an opening of the housing 41. And as one of these electronic components, an electronic component 30 to be cooled by the vapor chamber 1 is disposed inside the housing 41.

[0115] The vapor chamber 1 is installed inside a housing of a portable terminal or the like and attached to an electronic component 30 which is an object to be cooled such as a CPU. The electronic component 30 is attached directly to the outer surface 10b or the outer surface 20b of the vapor chamber 1 or via a highly thermally conductive adhesive, sheet, tape, or the like.

[0116] FIG. 19 shows a diagram for explaining the behavior of the working fluid. For ease of explanation, this figure is drawn from the same perspective as FIG. 17, and focuses on the condensate flow path 3 and the vapor flow path 4 formed within the sealed space 2. When the electronic component 30 generates heat, the heat is transmitted through the first sheet 10 by heat conduction, and the condensate present near the electronic component 30 within 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 30 is cooled.

[0117] The vaporized working fluid becomes vapor and moves through the vapor flow path 4. The movement of the vaporized working fluid may move within the vapor flow path 4 in a vibrating manner as indicated by the solid-line straight arrow in FIG. 19, or may move in a single direction away from the electronic component 30, which is the heat source, without vibrating although not shown in the figure. At this time, the curved portion 7 of the curved section is included in the vapor flow path 4. However, since the curved portion 7 has the above-described configuration, even if the flow path lengths are different, the difference in flow resistance is alleviated, and the working fluid moves through the vapor flow path 4 in a well-balanced manner. As a result, a high heat transport capacity can be exhibited. And during the movement of the working fluid, the working fluid is cooled while being sequentially deprived of heat by the first sheet 10 and the second sheet 20. The first sheet 10 and the second sheet 20 that have taken heat from the vapor transfer the heat to the housing of the portable terminal device or the like that is in contact with their outer surfaces 10b and 20b, and finally the heat is released to the outside air. Then, the working fluid that has been deprived of heat while moving through the vapor flow path 4 condenses and liquefies.

[0118] A part of the condensate generated in the vapor flow path 4 moves to the condensate flow path 3 through a communication opening or the like. Since the condensate flow path 3 of this embodiment includes the communication opening 14c and the communication opening 15c, the condensate is distributed to the plurality of condensate flow paths 3 through the communication opening 14c and the communication opening 15c.

[0119] The condensate that has entered the condensate flow path 3 moves closer to the electronic component 30, which is the heat source, as represented by the dotted-line straight arrow in FIG. 19, due to the capillary force by the condensate flow path. Then, it is vaporized again by the heat from the electronic component 30, which is the heat source, and the above process is repeated.

[0120] As described above, according to the vapor chamber 1, the movement of the working fluid in the vapor flow path and the high capillary force in the condensate flow path enable the smooth and good movement of the working fluid, thereby enhancing the heat transport capacity. In addition, in the vapor chamber 1, by forming a flow path having the curved portion 7, when the vapor chamber is arranged in an electronic device and is subject to restrictions on its arrangement and cannot form a flow path that is only linear, the heat generated from the heat source can be moved to a position where it is efficiently separated. And in the curved portion 7, since it is configured such that the difference in flow resistance is low in the plurality of vapor flow paths 4 as described above, the working fluid can be moved in a well-balanced manner, and the heat transport capacity can be enhanced.

[0121] Figures 20 to 27 are diagrams for explaining the vapor chamber 201 according to the second embodiment. Figure 20 is an external perspective view of the vapor chamber 201, and Figure 21 is an exploded perspective view of the vapor chamber 201.

[0122] As can be seen from Figures 20 and 21, the vapor chamber 201 has a first sheet 210, a second sheet 220, and a third sheet 230. And by overlapping and joining (diffusion bonding, soldering, etc.) the first sheet 210, the second sheet 220, and the third sheet 230, a sealed space 202 surrounded by the first sheet 210, the second sheet 220, and the third sheet 230 is formed between the first sheet 210 and the second sheet 220 (see Figure 25), and a working fluid is encapsulated in this sealed space 202.

[0123] In this embodiment, the first sheet 210 is a sheet-like member as a whole. The first sheet 210 is composed of flat surfaces on both the front and back, and includes an inner surface 210a, an outer surface 210b on the side opposite to the inner surface 210a, and a side surface 210c that forms the thickness across the inner surface 210a and the outer surface 210b.

[0124] The first sheet 210 includes a main body 211 and an injection part 212. The main body 211 is a sheet-like part that forms a sealed space through which the working fluid moves. In this embodiment, it is a rectangle with rounded corners (so-called R) in plan view. The injection part 212 is a part for injecting the working fluid into the sealed space formed by the first sheet 210, the second sheet 220, and the third sheet 230. In this embodiment, it is a sheet-like shape that is quadrangular in plan view and protrudes from the L-shape in plan view of the main body 211. In this embodiment, the injection part 212 of the first sheet 210 has flat surfaces on both the inner surface 210a side and the outer surface 210b side.

[0125] In this embodiment, the second sheet 220 is a sheet-like member as a whole. The second sheet 220 is composed of flat surfaces on both the front and back, and includes an inner surface 220a, an outer surface 220b on the opposite side of the inner surface 220a, and a side surface 220c that forms the thickness across the inner surface 220a and the outer surface 220b.

[0126] And the second sheet 220 also has a main body 221 and an injection part 222.

[0127] In this embodiment, the third sheet 230 is a sheet that is sandwiched and overlapped between the inner surface 210a of the first sheet 210 and the inner surface 220a of the second sheet 220, and a structure for the working fluid to move is formed in the main body 231. FIG. 22 shows a plan view of the third sheet 230. FIG. 24(a) is a view of the surface to be overlapped with the second sheet 220, and FIG. 24(b) is a view of the surface to be overlapped with the first sheet 210. Also, FIG. 23 shows a cross-section along the line indicated by XXII-XXII in FIG. 22(a), and FIG. 24 shows a cross-section along the line indicated by XXIII-XXIII in FIG. 22(a).

[0128] The third sheet 230 includes a main body 231 and an injection part 232. The main body 231 is a sheet-like part that forms a sealed space through which the working fluid moves. In this embodiment, it is L-shaped with a curved part in plan view. The injection part 232 is a part for injecting the working fluid into the sealed space formed by the first sheet 210, the second sheet 220, and the third sheet 230. In this embodiment, it is in the shape of a quadrangular sheet in plan view that protrudes from the L-shaped in plan view of the main body 231. An injection groove 232a is formed on the surface side that overlaps the first sheet 210 of the injection part 232. The injection groove 232a can be considered in the same way as the above-described injection groove 22a.

[0129] The main body 231 is provided with an outer peripheral joint part 233, an outer peripheral liquid flow path part 234, an inner liquid flow path part 235, a vapor flow path slit 236, and a vapor flow path communication groove 237.

[0130] The outer peripheral joint part 233 is a part formed along the outer periphery of the main body 231. One surface of the outer peripheral joint part 233 overlaps and is joined (such as diffusion bonding, brazing, etc.) to the surface of the first sheet 210, and the other surface overlaps and is joined (such as diffusion bonding, brazing, etc.) to the surface of the second sheet 220. Thereby, a sealed space 202 surrounded by the first sheet 210, the second sheet 220, and the third sheet 230 is formed, and the working fluid is enclosed therein. The outer peripheral joint part 233 can be considered in the same way as the above-described outer peripheral joint part 13.

[0131] The outer peripheral liquid flow path part 234 functions as a liquid flow path part and is a part that constitutes a part of the condensate flow path 3, which is a flow path through which the working fluid passes when it condenses and liquefies. The outer peripheral liquid flow path part 234 is formed along the inside of the outer peripheral joint part 233 in the main body 231 and is provided in an annular shape along the outer periphery of the sealed space 202. And a liquid flow path groove 234a is formed on the surface of the outer peripheral liquid flow path part 234 on the side facing the second sheet 220. In this embodiment, the liquid flow path groove 234a is provided only on the surface facing the second sheet 220, but in addition, a liquid flow path groove may also be provided on the surface of the outer peripheral liquid flow path part 234 on the side facing the first sheet 210. The outer peripheral liquid flow path part 234 and the liquid flow path groove 234a provided therein can be considered in the same way as the above-described outer peripheral liquid flow path part 14 and the liquid flow path groove 14a.

[0132] The inner fluid flow path portion 235 also functions as a fluid flow path portion and is a part of the condensate flow path 3 through which the working fluid passes when it condenses and liquefies. The inner fluid flow path portion 235 is formed in the main body 231 so as to have a curved portion and extend inside the ring of the annular outer peripheral fluid flow path portion 234. And a plurality (five in this embodiment) of inner fluid flow path portions 235 are arranged in a direction different from the extending direction and are disposed between the vapor flow path slits 236.

[0133] On the surface of the inner fluid flow path portion 235 facing the second sheet 220, a fluid flow path groove 235a, which is a groove parallel to the extending direction of the inner fluid flow path portion 235, is formed. The inner fluid flow path portion 235 and the fluid flow path groove 235a can be considered in the same way as the above-described inner fluid flow path portion 15 and the fluid flow path groove 15a. In this embodiment, the fluid flow path groove 235a is provided only on the surface facing the second sheet 220, but in addition, a fluid flow path groove may also be provided on the surface of the inner fluid flow path portion 235 facing the first sheet 210.

[0134] The vapor flow path slit 236 is a slit that constitutes the vapor flow path 4 and is a part where the working fluid in vapor and condensate states moves. The vapor flow path slit 236 is constituted by a slit having a curved portion formed inside the ring of the annular outer peripheral fluid flow path portion 434 in the main body 231. Specifically, the vapor flow path slit 236 in this embodiment is a slit formed between adjacent inner fluid flow path portions 235 and between the outer peripheral fluid flow path portion 234 and the inner fluid flow path portion 235. Therefore, the vapor flow path slit 236 penetrates in the thickness direction (z direction) of the third sheet 230. And a plurality (six in this embodiment) of vapor flow path slits 236 are arranged in a direction different from the extending direction. Therefore, as can be seen from FIG. 23, the third sheet 230 has a shape in which the outer peripheral fluid flow path portion 234, the inner fluid flow path portion 235, and the vapor flow path slits 236 are alternately repeated.

[0135] Such a vapor flow path slit 236 can be considered in the same way as the aspect of the vapor flow path 4 formed by combining the above-described vapor flow path groove 16 and vapor flow path groove 26.

[0136] In this embodiment, the cross-sectional shape of the vapor flow path slit 236 is formed such that a part of an elliptical arc overlaps with another part, and it protrudes at the center in the thickness direction. However, it is not limited to this, and other shapes such as a square, a rectangle, a trapezoid and other quadrilaterals, a triangle, a semi-circle, a crescent shape, and combinations thereof may also be used.

[0137] The vapor flow path communication groove 237 is a groove that forms a flow path for communicating a plurality of vapor flow path slits 236. Thereby, it is possible to balance the movement of the working fluid generated in the vapor flow path in the direction in which the inner liquid flow path portion 235 extends. Also, thereby, the equalization of the working fluid in the vapor flow path can be achieved, the vapor can be carried over a wider range, and the condensation liquid flow paths formed by many liquid flow path grooves 234a and liquid flow path grooves 235a can be efficiently utilized.

[0138] The vapor flow path communication groove 237 of this embodiment is formed between both ends in the direction in which the inner liquid flow path portion 235 extends and both ends in the direction in which the vapor flow path slit 236 extends, and the outer peripheral liquid flow path portion 234. The vapor flow path communication groove 237 only needs to be able to communicate adjacent vapor flow path slits 236, and its shape is not particularly limited, but it can be considered in the same way as the flow path formed by overlapping the above-described vapor flow path communication groove 17 and vapor flow path communication groove 27.

[0139] Also, regarding the third sheet 230 as well, the vapor chamber 201 is provided with a straight portion 238a, a straight portion 238b, and a curved portion 238c such that the condensation liquid flow path 3 and the vapor flow path 4 have a straight portion and a curved portion in the sealed space 202. The concept of these straight portions and curved portions is the same as that described so far.

[0140] Such a third sheet 230 can be manufactured by etching performed individually for each side, simultaneous etching from both sides, press working, or cutting.

[0141] Figs. 25 to 27 show diagrams explaining the structure when the first sheet 210, the second sheet 220, and the third sheet 230 are combined to form the vapor chamber 201. Fig. 25 shows a cross-sectional view along the line indicated by XXIV-XXIV in Fig. 20, and Fig. 26 shows an enlarged view of a part of Fig. 25. Fig. 27 shows a cross-sectional view along the line indicated by XXVI-XXVI in Fig. 20.

[0142] As can be seen from Fig. 20 and Figs. 25 to 27, the first sheet 210, the second sheet 220, and the third sheet 230 are arranged and joined so as to be overlapped to form the vapor chamber 201. At this time, the inner surface 210a of the first sheet 210 and one surface of the third sheet 230 (the surface on the side where the liquid flow path grooves 234a and 235a are not arranged) are arranged to face each other, and the inner surface 220a of the second sheet 220 and the other surface of the third sheet 230 (the surface on the side where the liquid flow path grooves 234a and 235a are arranged) are overlapped to face each other. Similarly, the injection portions 212, 222, and 232 of each sheet are also overlapped.

[0143] As a result, a hollow portion surrounded by the first sheet 210, the second sheet 220, and the third sheet 230 is formed between the first sheet 210 and the second sheet 220, and the working fluid is sealed here to form the sealed space 202. This becomes the condensate flow path 3 and the vapor flow path 4. Regarding the forms of the condensate flow path 3 and the vapor flow path 4 in these sealed spaces 202, the same concept as the above-described vapor chamber 1 can be applied. In this embodiment, an example is shown in which the condensate flow path 3 is formed only on one side in the thickness direction of the outer peripheral liquid flow path portion 234 and the inner liquid flow path portion 235, but the present invention is not limited to this, and the condensate flow path may be formed on the other side in the thickness direction of the outer peripheral liquid flow path portion 234 and the inner liquid flow path portion 235.

[0144] In the above-described embodiment, the vapor chamber having a curved portion at the intersection where two straight portions intersect at 90 degrees and extend in an L-shape has been described. However, the form of the curvature is not limited to this, and the form of the curved portion described above can be applied even in other forms. For example, the curved portion can be applied to the intersection when two straight portions extend in a direction where they intersect in a T-shape, the intersection when two straight portions extend in a direction where they intersect in a cross shape, the intersection when two straight lines intersect at an acute angle (an angle smaller than 90 degrees) and extend in a V-shape, and the intersection when two straight lines intersect at an obtuse angle (an angle larger than 90 degrees) and extend in a V-shape.

Explanation of Signs

[0145] 1 Vapor chamber 2 Sealed space 3 Condensate flow path 4 Vapor flow path 10 First sheet 11 Main body 12 Injection part 13 Outer peripheral joint part 14 Outer peripheral liquid flow path part 14a Liquid flow path groove 14c Communication opening 15 Inner liquid flow path part 15a Liquid flow path groove 15c Communication opening 16 Vapor flow path groove 17 Vapor flow path communication groove 20 Second sheet 21 Main body 22 Injection part 23 Outer peripheral joint part 24 Outer peripheral liquid flow path part 25 Inner liquid flow path part 26 Vapor flow path groove 27 Vapor flow path communication groove 230 Third sheet 236 Vapor flow path slit

Claims

【Claim 1】 A vapor chamber in which a working fluid is enclosed in a sealed space, wherein the sealed space is provided with a capillary structure through which the working fluid moves in a condensed liquid state, and a plurality of vapor flow paths through which the working fluid moves in a vapor and condensed liquid state, and has a curved portion where the extending direction of the plurality of vapor flow paths changes, the plurality of vapor flow paths are arranged at intervals from each other at the curved portion, at the curved portion, the center position of the arc of the radius of curvature of at least one of the vapor flow paths is shifted with respect to the center position of the arc of the radius of curvature of another one of the vapor flow paths, a vapor chamber.

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