Wick sheet for vapor chamber, vapor chamber and electronic device

Abstract

To inhibit deterioration of performance of a vapor chamber.SOLUTION: A wick sheet for a vapor chamber according to the invention is a wick sheet for a vapor chamber which is disposed between a first sheet and a second sheet of a vapor chamber in which a working fluid having freezing expansibility is enclosed. The wick sheet for the vapor chamber includes: a frame body part; a land part provided in the frame body part; a steam flow passage part which is provided between the frame body part and the land part and in which steam of the working fluid passes; and a liquid flow passage part which is provided at the land part and communicates with the steam flow passage part and in which a liquid working fluid passes. The frame body part has frame body protruding parts formed protruding toward the steam flow passage part.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a wick sheet for a vapor chamber, a vapor chamber, and an electronic device. [Background technology]

[0002] Devices that generate heat, such as central processing units (CPUs), light-emitting diodes (LEDs), and power semiconductors used in mobile devices such as handheld devices and tablet computers, are cooled by heat dissipation members such as heat pipes (see, for example, Patent Document 1). In recent years, thinner heat dissipation members have been required to make mobile devices thinner, and vapor chambers, which can be made thinner than heat pipes, have been developed. A working fluid is sealed inside the vapor chamber, and this working fluid absorbs and dissipates the heat from the device, thereby cooling the device.

[0003] More specifically, the working fluid in the vapor chamber receives heat from the device in the portion (evaporator) close to the device and evaporates into vapor (working vapor). The working vapor diffuses away from the evaporator in the vapor channel, cools, and condenses into liquid. The vapor chamber is provided with a liquid channel with a capillary structure (wick). The condensed working fluid (working liquid) enters the liquid channel from the vapor channel and flows through the liquid channel toward the evaporator. The working liquid then receives heat again in the evaporator and evaporates. In this way, the working fluid circulates within the vapor chamber while repeatedly changing phases, i.e., evaporating and condensing, thereby transferring heat from the device and increasing heat dissipation efficiency. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-82698 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in a temperature environment below the freezing point of the working fluid sealed in the vapor chamber, the working fluid may freeze, causing the frozen working fluid to partially block the vapor flow path in the vapor chamber, potentially reducing the performance of the vapor chamber.

[0006] The present invention has been made in consideration of these points, and aims to provide a wick sheet for a vapor chamber, a vapor chamber, and an electronic device that can suppress deterioration in the performance of the vapor chamber. [Means for solving the problem]

[0007] The present invention provides A wick sheet for a vapor chamber interposed between a first sheet and a second sheet of the vapor chamber in which a working fluid is sealed, A frame body portion; a land portion provided within the frame portion; a vapor flow path portion provided between the frame portion and the land portion, through which vapor of the working fluid passes; a liquid flow path portion provided in the land portion, communicating with the vapor flow path portion, through which the liquid working fluid passes, a wick sheet for a vapor chamber, wherein the frame portion has a plurality of frame protrusions formed in a convex shape toward the inside of the vapor flow path portion in a plan view; to provide.

[0008] In the wick sheet for the vapor chamber described above, The plurality of frame body protrusions include a first protrusion provided on at least one of a pair of inner end portions extending in a first direction of the frame body. This may be done.

[0009] In the wick sheet for the vapor chamber described above, The land portion has a longitudinal direction along the first direction. This may be done.

[0010] In addition, in the wick sheet for the vapor chamber described above, The plurality of frame body protrusions include a second protrusion provided on at least one of a pair of inner end portions of the frame body extending in a second direction perpendicular to the first direction. This may be done.

[0011] In addition, in the wick sheet for the vapor chamber described above, The frame protrusion may have a rectangular, triangular or curved shape in a plan view.

[0012] In addition, in the wick sheet for the vapor chamber described above, When viewed in a cross section along the thickness direction of the wick sheet, the frame convex portion has a first curved surface provided on one side in the thickness direction, a second curved surface provided on the other side in the thickness direction, and a protrusion portion where the first curved surface and the second curved surface join together and protrude into the steam flow path portion. This may be done.

[0013] In addition, in the wick sheet for the vapor chamber described above, When viewed in a cross section along the thickness direction, the protrusion is positioned more inward of the steam flow path portion than a first end of the first curved surface provided on the opposite side to the protrusion, and is positioned more inward of the steam flow path portion than a second end of the second curved surface provided on the opposite side to the protrusion. This may be done.

[0014] In addition, in the wick sheet for the vapor chamber described above, When viewed in a cross section along the thickness direction, the protrusion is positioned more inward of the steam flow path portion than a first end of the first curved surface provided on the opposite side to the protrusion, and a second end of the second curved surface provided on the opposite side to the protrusion is positioned more inward of the steam flow path portion than the protrusion. This may be done.

[0015] In addition, in the wick sheet for the vapor chamber described above, the plurality of frame body protrusions include first end side protrusions and second end side protrusions that are arranged alternately in a plan view, In the first end-side convex portion, when viewed in a cross section along the thickness direction, the protrusion is positioned more inward of the steam flow path portion than a second end of the second curved surface provided on the opposite side to the protrusion, and a first end of the first curved surface provided on the opposite side to the protrusion is positioned more inward of the steam flow path portion than the protrusion, In the second end side convex portion, when viewed in a cross section along the thickness direction, the protrusion is positioned more inward of the steam flow path portion than the first end, and the second end is positioned more inward of the steam flow path portion than the protrusion. This may be done.

[0016] The present invention also provides A wick sheet for a vapor chamber interposed between a first sheet and a second sheet of the vapor chamber in which a working fluid is sealed, A frame body portion; a land portion provided within the frame portion; a seat space provided between the frame portion and the land portion; a groove portion provided in the land portion and communicating with the seat space, a wick sheet for a vapor chamber, wherein the frame portion has a plurality of frame protrusions formed in a convex shape toward the inside of the sheet space in a plan view; to provide.

[0017] The present invention also provides The first sheet and The second sheet, a vapor chamber including the above-mentioned wick sheet for the vapor chamber interposed between the first sheet and the second sheet; to provide.

[0018] In the vapor chamber described above, a condensation region in which the working fluid condenses; an evaporation region in which the working fluid evaporates; The frame protrusion is provided in the condensation region. This may be done.

[0019] In addition, in the vapor chamber described above, The working fluid having freeze expansion properties is sealed in. This may be done.

[0020] The present invention also provides Housing and a device contained within the housing; and and a vapor chamber as described above in thermal contact with the device. [Effects of the Invention]

[0021] According to the present invention, it is possible to suppress the deterioration of the performance of the vapor chamber. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic perspective view illustrating an electronic device according to an embodiment. [Figure 2] FIG. 2 is a top view showing a vapor chamber according to an embodiment. [Figure 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. [Figure 4] FIG. 4 is a top view of the lower sheet of FIG. [Figure 5] FIG. 5 is a bottom view of the upper sheet of FIG. [Figure 6] FIG. 6 is a top view of the wick sheet of FIG. [Figure 7] FIG. 7 is an enlarged cross-sectional view of a portion of FIG. [Figure 8]FIG. 8 is a partially enlarged top view of the liquid flow path portion shown in FIG. [Figure 9] 9 is a partially enlarged top view showing a first protrusion provided on the frame body shown in FIG. 6. FIG. [Figure 10] 10 is a partially enlarged top view showing a second protrusion provided on the frame body shown in FIG. 6. FIG. [Figure 11] FIG. 11 is a cross-sectional view taken along line BB in FIG. [Figure 12] FIG. 12 is a view for explaining a wick sheet preparation step in the method for manufacturing a vapor chamber according to the embodiment. [Figure 13] FIG. 13 is a view for explaining an etching step in the method for manufacturing a vapor chamber according to the embodiment. [Figure 14] FIG. 14 is a view for explaining a bonding step in the manufacturing method of the vapor chamber according to the embodiment. [Figure 15] FIG. 15 is a partially enlarged top view showing a modification of FIG. [Figure 16] FIG. 16 is a partially enlarged top view showing a modification of FIG. [Figure 17] FIG. 17 is a cross-sectional view showing a modification of FIG. [Figure 18] FIG. 18 is a cross-sectional view showing a modification of FIG. [Figure 19] FIG. 19 is a top view showing a modification of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings attached to this specification, the scale and aspect ratios of the actual objects have been appropriately changed and exaggerated for the sake of convenience in illustration and understanding.

[0024] Furthermore, terms used in this specification that specify shapes, geometric conditions, physical properties, and their degrees, such as "parallel," "orthogonal," and "identical," as well as lengths, angles, and physical property values, are not limited to their strict meanings but are interpreted to include the range within which similar functions can be expected. Furthermore, in the drawings, for clarity, the shapes of multiple parts that can be expected to have similar functions are depicted in a regular pattern. However, the shapes of these parts may differ from each other as long as the functions can be expected without being limited to strict meanings. Furthermore, in the drawings, boundaries indicating the joining surfaces between components are shown as simple straight lines for convenience. However, these boundaries are not required to be strictly straight lines, and the shape of the boundaries is arbitrary as long as the desired joining performance can be expected.

[0025] 1 to 14, a wick sheet for a vapor chamber, a vapor chamber, and an electronic device according to an embodiment of the present invention will be described. Vapor chamber 1 according to this embodiment is a device mounted on electronic device E to cool device D, which is a heat-generating body housed in electronic device E. Examples of device D include electronic devices (cooled devices) that generate heat, such as central processing units (CPUs), light-emitting diodes (LEDs), and power semiconductors used in mobile devices such as portable terminals and tablet terminals.

[0026] First, an electronic device E equipped with a vapor chamber 1 according to this embodiment will be described using a tablet terminal as an example. As shown in FIG. 1, the electronic device E (tablet terminal) includes a housing H, a device D housed in the housing H, and a vapor chamber 1. In the electronic device E shown in FIG. 1, a touch panel display TD is provided on the front surface of the housing H. The vapor chamber 1 is housed in the housing H and arranged so as to be in thermal contact with the device D. This allows the vapor chamber 1 to receive heat generated in the device D when the electronic device E is in use. The heat received by the vapor chamber 1 is released to the outside of the vapor chamber 1 via working fluids 2a and 2b, which will be described later. In this way, the device D is effectively cooled. When the electronic device E is a tablet terminal, the device D corresponds to a central processing unit or the like.

[0027] Next, a vapor chamber 1 according to this embodiment will be described. As shown in FIGS. 2 and 3, the vapor chamber 1 has a sealed space 3 in which working fluids 2a and 2b are sealed, and is configured to effectively cool the device D of the electronic device E described above by repeatedly changing phases of the working fluids 2a and 2b in the sealed space 3. Examples of the working fluids 2a and 2b include pure water, ethanol, methanol, acetone, etc., and mixtures thereof. The working fluids 2a and 2b may have freeze-expansion properties. In other words, the working fluids 2a and 2b may be fluids that expand when frozen. Examples of the freeze-expansion working fluids 2a and 2b include pure water, or an aqueous solution of pure water to which an additive such as alcohol has been added.

[0028] 2 and 3, the vapor chamber 1 includes a lower sheet 10 (first sheet), an upper sheet 20 (second sheet), and a wick sheet for the vapor chamber (hereinafter simply referred to as wick sheet 30) interposed between the lower sheet 10 and the upper sheet 20. The vapor chamber 1 according to this embodiment has the lower sheet 10, wick sheet 30, and upper sheet 20 stacked in this order.

[0029] The vapor chamber 1 is generally formed in the shape of a thin flat plate. The planar shape of the vapor chamber 1 is arbitrary, and may be a rectangle as shown in FIG. 2. The planar shape of the vapor chamber 1 may be, for example, a rectangle with one side 1 cm and the other 3 cm, or a square with one side 15 cm, and the planar dimensions of the vapor chamber 1 are arbitrary. In this embodiment, as an example, an example in which the planar shape of the vapor chamber 1 is a rectangle with the X direction as the longitudinal direction will be described. In this case, as shown in FIGS. 4 to 6, the lower sheet 10, the upper sheet 20, and the wick sheet 30 may have the same planar shape as the vapor chamber 1. Furthermore, the planar shape of the vapor chamber 1 is not limited to a rectangle, and may be any shape, such as a circle, an ellipse, an L-shape, or a T-shape.

[0030] As shown in FIG. 2, the vapor chamber 1 has an evaporation region SR where the working fluids 2a and 2b evaporate, and a condensation region CR where the working fluids 2a and 2b condense.

[0031] The evaporation region SR is an area that overlaps with the device D in a planar view and is an area where the device D is attached. The evaporation region SR can be located anywhere in the vapor chamber 1. In this embodiment, the evaporation region SR is formed on one side of the vapor chamber 1 in the X direction (the left side in Figure 2). Heat from the device D is transferred to the evaporation region SR, and this heat causes the liquid working fluid (appropriately referred to as working fluid 2b) to evaporate in the evaporation region SR. The heat from the device D can be transferred not only to the area that overlaps with the device D in a planar view, but also to the surrounding area of ​​that area. Therefore, the evaporation region SR includes the area that overlaps with the device D in a planar view and the surrounding area. Here, a planar view refers to a view of the vapor chamber 1 from a direction perpendicular to the surface that receives heat from the device D (the second upper sheet surface 20b of the upper sheet 20, described later) and the surface that releases the received heat (the first lower sheet surface 10a of the lower sheet 10, described later). For example, as shown in Figure 2, this corresponds to a view of the vapor chamber 1 from above or below.

[0032] The condensation region CR is a region that does not overlap with the device D in a plan view, and is a region where the vapor of the working fluid (referred to as working vapor 2a as appropriate) releases heat and condenses. The condensation region CR can also be said to be a region surrounding the evaporation region SR. In this embodiment, the condensation region CR is formed on the other side of the vapor chamber 1 in the X direction (the right side in FIG. 2). In the condensation region CR, heat from the working vapor 2a is released to the lower sheet 10, and the working vapor 2a is cooled and condensed in the condensation region CR.

[0033] When the vapor chamber 1 is installed inside a mobile terminal, the up-down relationship may be lost depending on the orientation of the mobile terminal. However, in this embodiment, for convenience, the sheet that receives heat from the device D will be referred to as the upper sheet 20, and the sheet that releases the received heat will be referred to as the lower sheet 10. For this reason, the following description will be given assuming that the lower sheet 10 is positioned on the lower side and the upper sheet 20 is positioned on the upper side.

[0034] As shown in FIG. 3, the lower sheet 10 has a first lower sheet surface 10a provided on the side opposite the wick sheet 30, and a second lower sheet surface 10b provided on the side opposite the first lower sheet surface 10a (i.e., the wick sheet 30 side). The lower sheet 10 may be formed to be flat overall, or may have a constant thickness overall. A housing member Ha that forms part of a housing H of a mobile terminal or the like is attached to this first lower sheet surface 10a. The first lower sheet surface 10a may be entirely covered by the housing member Ha. As shown in FIG. 4, alignment holes 12 may be provided in the four corners of the lower sheet 10.

[0035] As shown in Fig. 3, the upper sheet 20 has a first upper sheet surface 20a provided on the wick sheet 30 side and a second upper sheet surface 20b provided on the opposite side to the first upper sheet surface 20a. The upper sheet 20 may be formed to be generally flat, or may have a uniform thickness overall. The device D described above is attached to this second upper sheet surface 20b. As shown in Fig. 5, alignment holes 22 may be provided in the four corners of the upper sheet 20.

[0036] 3, the wick sheet 30 includes a sheet body 31 and a vapor flow path portion 50 (sheet space) provided in the sheet body 31. The sheet body 31 has a first body surface 31a and a second body surface 31b provided on the opposite side to the first body surface 31a. The first body surface 31a is disposed on the side of the lower sheet 10, and the second body surface 31b is disposed on the side of the upper sheet 20.

[0037] The second lower sheet surface 10b of the lower sheet 10 and the first main body surface 31a of the sheet main body 31 may be permanently bonded to each other by diffusion bonding. Similarly, the first upper sheet surface 20a of the upper sheet 20 and the second main body surface 31b of the sheet main body 31 may be permanently bonded to each other by diffusion bonding. The lower sheet 10, the upper sheet 20, and the wick sheet 30 may be bonded by other methods such as brazing, as long as they are permanently bonded, rather than by diffusion bonding. The term "permanently bonded" is not limited to a strict meaning and is used to mean that the lower sheet 10 and the wick sheet 30 are bonded to a degree that allows the sealing of the sealed space 3 to be maintained, and that the upper sheet 20 and the wick sheet 30 are bonded to a degree that allows the sealing of the sealed space 3 to be maintained when the vapor chamber 1 is in operation.

[0038] 3 and 6, the sheet body 31 of the wick sheet 30 according to this embodiment has a frame portion 32 formed in the shape of a rectangular frame in a plan view, and a land portion 33 provided within the frame portion 32. The frame portion 32 and the land portion 33 are portions that are not etched in the etching step described below, and the material of the wick sheet 30 remains.

[0039] In this embodiment, the frame portion 32 is formed into a rectangular frame shape in a plan view. A steam flow path portion 50 is defined inside the frame portion 32. That is, the working steam 2a flows around the land portion 33 inside the frame portion 32. The frame portion 32 also has a pair of inner end portions 32a extending in the X direction and a pair of inner end portions 32b extending in the Y direction perpendicular to the X direction. The inner end portions 32a, 32b of the frame portion 32 are provided with a plurality of frame protrusions 70, which will be described later.

[0040] In this embodiment, the land portions 33 may extend in an elongated shape with the X direction (first direction, left-right direction in FIG. 6) as the longitudinal direction in a plan view, and the planar shape of the land portions 33 may be an elongated rectangle. Furthermore, the lands 33 may be arranged parallel to one another and spaced at equal intervals in the Y direction (second direction, up-down direction in FIG. 6). The working steam 2a flows around each land portion 33 and is transported toward the condensation region CR. This prevents the flow of the working steam 2a from being obstructed. The width w1 (see FIG. 7) of the land portion 33 may be, for example, 100 μm to 1500 μm. Here, the width w1 of the land portion 33 refers to the dimension of the land portion 33 in the Y direction and the dimension at the position where the penetration portion 34, described later, is present in the Z direction (thickness direction of the wick sheet 30).

[0041] The frame body 32 and each land portion 33 are diffusion bonded to the lower sheet 10 and also to the upper sheet 20. This improves the mechanical strength of the vapor chamber 1. A wall surface 53a of the lower vapor flow path recess 53 and a wall surface 54a of the upper vapor flow path recess 54 (described later) form the side walls of the land portion 33. The first main body surface 31a and the second main body surface 31b of the sheet main body 31 may be formed flat across the frame body 32 and each land portion 33.

[0042] The vapor flow path 50 is a path through which the working vapor 2a mainly passes. The vapor flow path 50 extends from the first main body surface 31a to the second main body surface 31b, and penetrates the sheet main body 31 of the wick sheet 30.

[0043] As shown in FIG. 6 , the steam flow path section 50 in this embodiment has a first steam path 51 and a plurality of second steam paths 52. The first steam path 51 is formed between the frame body section 32 and the land section 33. This first steam path 51 is formed inside the frame body section 32 and continuously outside the land section 33. The first steam path 51 has a planar shape of a rectangular frame. The second steam path 52 is formed between adjacent land sections 33. The second steam path 52 has a planar shape of an elongated rectangle. The steam flow path section 50 is partitioned into the first steam path 51 and the plurality of second steam paths 52 by the plurality of land sections 33.

[0044] 3, the first steam passage 51 and the second steam passage 52 extend from the first main body surface 31a to the second main body surface 31b of the seat body 31. The first steam passage 51 and the second steam passage 52 are each formed by a lower steam flow path recess 53 provided in the first main body surface 31a and an upper steam flow path recess 54 provided in the second main body surface 31b. The lower steam flow path recess 53 and the upper steam flow path recess 54 are in communication with each other, and the first steam passage 51 and the second steam passage 52 of the steam flow path section 50 are formed to extend from the first main body surface 31a to the second main body surface 31b.

[0045] The lower steam flow path recess 53 is formed in a concave shape on the first main body surface 31a by etching the first main body surface 31a of the wick sheet 30 in an etching step described below. As a result, the lower steam flow path recess 53 has a curved wall surface 53a, as shown in Fig. 7. The wall surface 53a defines the lower steam flow path recess 53 and is curved in a shape that bulges toward the second main body surface 31b. The lower steam flow path recess 53 constitutes a part (lower half) of the first steam passage 51 and a part (lower half) of the second steam passage 52.

[0046] The upper steam flow path recess 54 is formed in a concave shape on the second main body surface 31b by being etched from the second main body surface 31b of the wick sheet 30 in an etching step described below. As a result, the upper steam flow path recess 54 has a curved wall surface 54a, as shown in Fig. 7. This wall surface 54a defines the upper steam flow path recess 54 and is curved in a shape that bulges toward the first main body surface 31a. Such an upper steam flow path recess 54 constitutes a part (upper half) of the first steam path 51 and a part (upper half) of the second steam path 52.

[0047] As shown in FIG. 7 , the wall surface 53a of the lower steam flow path recess 53 and the wall surface 54a of the upper steam flow path recess 54 are connected to form the through-portion 34. The wall surfaces 53a and 54a are each curved toward the through-portion 34. This allows the lower steam flow path recess 53 and the upper steam flow path recess 54 to communicate with each other. In this embodiment, the planar shape of the through-portion 34 in the first steam passage 51 is a rectangular frame like the first steam passage 51, and the planar shape of the through-portion 34 in the second steam passage 52 is an elongated rectangular like the second steam passage 52. The through-portion 34 may be defined by a ridgeline formed by the joining of the wall surface 53a of the lower steam flow path recess 53 and the wall surface 54a of the upper steam flow path recess 54, which juts out inward. The planar area of ​​the steam flow path section 50 is minimized at this through-portion 34. The widths w2, w2' of the through portion 34 (see FIG. 7) may be, for example, 400 μm to 1600 μm. Here, the width w2 of the through portion 34 corresponds to the gap between the land portions 33 adjacent to each other in the Y direction. Furthermore, the width w2' of the through portion 34 corresponds to the gap between the frame portion 32 (more specifically, the inner ends 32a, 32b of the frame portion 32 on which the frame protrusion 70 described later is not provided) and the land portion 33.

[0048] The position of the through-hole 34 in the Z direction (thickness direction of the wick sheet 30, vertical direction in FIG. 7) may be an intermediate position between the first lower sheet surface 10a and the upper sheet surface 20b, or may be a position shifted downward or upward from the intermediate position. The position of the through-hole 34 is arbitrary as long as the lower steam flow path recess 53 and the upper steam flow path recess 54 are in communication with each other.

[0049] In the present embodiment, the cross-sectional shapes of the first steam passage 51 and the second steam passage 52 are formed to include the through-holes 34 defined by ridges formed to protrude inward, but this is not limited to this. For example, the cross-sectional shapes of the first steam passage 51 and the second steam passage 52 may be trapezoidal, rectangular, or barrel-shaped.

[0050] The steam flow path section 50 including the first steam path 51 and the second steam path 52 configured in this manner constitutes a part of the above-mentioned sealed space 3. As shown in Fig. 3, the steam flow path section 50 in this embodiment is defined mainly by the lower sheet 10, the upper sheet 20, and the frame portion 32 and land portion 33 of the above-mentioned sheet main body 31. Each of the steam paths 51, 52 has a relatively large flow path cross-sectional area so that the working steam 2a can pass through.

[0051] Here, in order to clarify the drawing, FIG. 3 shows the first steam passage 51, the second steam passage 52, etc. in an enlarged scale, and the number and arrangement of these steam passages 51, 52, etc. are different from those in FIGS. 2 and 6.

[0052] Although not shown, a plurality of support portions that support the land portion 33 on the frame portion 32 may be provided within the steam channel portion 50. Also, support portions that support adjacent land portions 33 may be provided. These support portions may be provided on both sides of the land portion 33 in the X direction, or on both sides of the land portion 33 in the Y direction. The support portion is preferably formed so as not to impede the flow of the working vapor 2a diffusing through the vapor flow path portion 50. For example, the support portion may be disposed on one of the first main body surface 31a and the second main body surface 31b of the sheet main body 31 of the wick sheet 30, with a space forming a vapor flow path recess formed on the other side. This allows the thickness of the support portion to be thinner than the thickness of the sheet main body 31, preventing the first vapor path 51 and the second vapor path 52 from being separated in the X and Y directions.

[0053] As shown in FIG. 6, alignment holes 35 may be provided at the four corners of the sheet body 31 of the wick sheet 30.

[0054] 2, the vapor chamber 1 may further include an injection part 4 at one edge in the X direction, which injects the working fluid 2b into the sealed space 3. In the embodiment shown in FIG. 2, the injection part 4 is disposed on the evaporation region SR side, and protrudes outward from the edge on the evaporation region SR side.

[0055] More specifically, the injection section 4 may be configured to include a lower injection protrusion 11 (see FIG. 4) constituting the lower sheet 10, an upper injection protrusion 21 (see FIG. 5) constituting the upper sheet 20, and a wick sheet injection protrusion 36 (see FIG. 6) constituting the sheet main body 31 of the wick sheet 30. An injection flow path 37 is formed in the wick sheet injection protrusion 36. This injection flow path 37 extends from the first main body surface 31a to the second main body surface 31b of the sheet main body 31 and penetrates the sheet main body 31 (wick sheet injection protrusion 36) in the Z direction. The injection flow path 37 is also connected to the vapor flow path section 50, and the working fluid 2b is injected into the sealed space 3 through the injection flow path 37. Depending on the arrangement of the liquid flow path section 60, the injection flow path 37 may be connected to the liquid flow path section 60. The upper and lower surfaces of the wick sheet injection protrusion 36 are flat, and the upper surface of the lower injection protrusion 11 and the lower surface of the upper injection protrusion 21 are also flat. The planar shapes of the injection protrusions 11, 21, and 36 may be the same.

[0056] In this embodiment, the injection portion 4 is provided on one edge of a pair of edges in the X direction of the vapor chamber 1, but the invention is not limited to this and the injection portion 4 can be provided at any position. Furthermore, the injection flow path 37 provided in the wick sheet injection protrusion 36 does not need to penetrate the sheet main body 31 as long as it can inject the working fluid 2b. In this case, the injection flow path 37 communicating with the vapor flow path portion 50 can be formed by etching only one of the first main body surface 31a and the second main body surface 31b of the sheet main body 31.

[0057] As shown in FIGS. 3, 6, and 7, a liquid flow path portion 60 (groove portion) through which mainly the working fluid 2b passes is provided on the second main body surface 31b of the sheet main body 31 of the wick sheet 30. This liquid flow path portion 60 constitutes a part of the sealed space 3 and is connected to the vapor flow path portion 50. The liquid flow path portion 60 is configured as a capillary structure (wick) for transporting the working fluid 2b to the evaporation region SR. In this embodiment, the liquid flow path portion 60 is provided on the second main body surface 31b of each land portion 33 of the wick sheet 30. The liquid flow path portion 60 may be formed over the entire second main body surface 31b of each land portion 33. The liquid flow path portion 60 may not be provided on the first main body surface 31a of each land portion 33.

[0058] The liquid flow path section 60 is composed of a plurality of grooves provided in the second main body surface 31b. In this embodiment, as shown in Fig. 8, the liquid flow path section 60 has a plurality of liquid flow path main grooves 61 through which the working fluid 2b passes, and a plurality of liquid flow path communication grooves 65 that communicate with the liquid flow path main grooves 61.

[0059] As shown in Fig. 8, each liquid flow path mainstream groove 61 is formed to extend in the X direction. Each liquid flow path mainstream groove 61 has a flow path cross-sectional area smaller than the first vapor passage 51 or the second vapor passage 52 of the vapor flow path section 50 so that the working liquid 2b flows mainly by capillary action. As a result, the liquid flow path mainstream groove 61 is configured to transport the working liquid 2b condensed from the working vapor 2a to the evaporation region SR. Each liquid flow path mainstream groove 61 may be arranged at equal intervals in the Y direction.

[0060] The liquid flow path main grooves 61 are formed by etching from the second main body surface 31b of the sheet body 31 of the wick sheet 30 in an etching process described below. As a result, the liquid flow path main grooves 61 have wall surfaces 62 formed in a curved shape, as shown in Fig. 7. These wall surfaces 62 define the liquid flow path main grooves 61 and are curved in a shape that bulges toward the first main body surface 31a.

[0061] 7 and 8, the width w3 (dimension in the Y direction) of the liquid flow path mainstream groove 61 may be, for example, 5 μm to 150 μm. Note that the width w3 of the liquid flow path mainstream groove 61 refers to the dimension at the second main body surface 31b. Also, as shown in FIG. 7, the depth h1 (dimension in the Z direction) of the liquid flow path mainstream groove 61 may be, for example, 3 μm to 150 μm.

[0062] As shown in FIG. 8 , each liquid flow path communication groove 65 extends in a direction different from the X direction. In this embodiment, each liquid flow path communication groove 65 is formed to extend in the Y direction, perpendicular to the liquid flow path mainstream grooves 61. Some liquid flow path communication grooves 65 are arranged to connect adjacent liquid flow path mainstream grooves 61 to each other. Other liquid flow path communication grooves 65 are arranged to connect the vapor flow path section 50 (first vapor passage 51 or second vapor passage 52) to the liquid flow path mainstream groove 61. In other words, the liquid flow path communication groove 65 extends from the edge of the land portion 33 in the Y direction to the liquid flow path mainstream groove 61 adjacent to that edge. In this way, the first vapor passage 51 or second vapor passage 52 of the vapor flow path section 50 and the liquid flow path mainstream groove 61 are connected to each other.

[0063] The liquid flow path communication groove 65 has a flow path cross-sectional area smaller than the first vapor passage 51 or the second vapor passage 52 of the vapor flow path section 50 so that the working fluid 2b flows mainly by capillary action. The liquid flow path communication grooves 65 may be arranged at equal intervals in the X direction.

[0064] Like the liquid flow path mainstream groove 61, the liquid flow path connecting groove 65 is also formed by etching, and has wall surfaces (not shown) that are formed in a curved shape similar to the liquid flow path mainstream groove 61. As shown in Fig. 8, the width w4 (dimension in the X direction) of the liquid flow path connecting groove 65 may be equal to the width w3 of the liquid flow path mainstream groove 61, or may be greater or smaller than the width w3. The depth of the liquid flow path connecting groove 65 may be equal to the depth h1 of the liquid flow path mainstream groove 61, or may be greater or smaller than the depth h1.

[0065] As shown in FIG. 8 , a liquid flow path convex row 63 is provided between adjacent liquid flow path mainstream grooves 61. Each liquid flow path convex row 63 includes a plurality of liquid flow path convex sections 64 (liquid flow path protrusions) arranged in the X direction. The liquid flow path convex sections 64 are provided within the liquid flow path section 60, protrude from the sheet main body 31, and abut against the upper sheet 20. Each liquid flow path convex section 64 is formed in a rectangular shape with the X direction as its longitudinal direction in a plan view. A liquid flow path mainstream groove 61 is interposed between adjacent liquid flow path convex sections 64 in the Y direction, and a liquid flow path communication groove 65 is interposed between adjacent liquid flow path convex sections 64 in the X direction. The liquid flow path communication groove 65 is formed to extend in the Y direction and communicates with adjacent liquid flow path mainstream grooves 61 in the Y direction. This allows the working fluid 2b to move back and forth between these liquid flow path mainstream grooves 61.

[0066] The liquid flow path convex portion 64 is a portion that is not etched in the etching step described below, and remains as the material of the wick sheet 30. In this embodiment, as shown in Fig. 8, the planar shape of the liquid flow path convex portion 64 (the shape at the position of the second main body surface 31b of the sheet main body 31 of the wick sheet 30) is rectangular.

[0067] In this embodiment, the liquid flow path convex portions 64 are arranged in a staggered pattern. More specifically, the liquid flow path convex portions 64 of liquid flow path convex portion rows 63 adjacent to each other in the Y direction are arranged with a mutual offset in the X direction. This offset amount may be half the arrangement pitch of the liquid flow path convex portions 64 in the X direction. The width w5 (dimension in the Y direction) of the liquid flow path convex portions 64 may be, for example, 5 μm to 500 μm. Note that the width w5 of the liquid flow path convex portion 64 refers to the dimension on the second main body surface 31b. Note that the arrangement of the liquid flow path convex portions 64 is not limited to a staggered pattern and may be arranged in parallel. In this case, the liquid flow path convex portions 64 of the liquid flow path convex portion rows 63 adjacent to each other in the Y direction are also aligned in the X direction.

[0068] The liquid flow path mainstream groove 61 includes a liquid flow path intersection 66 that communicates with the liquid flow path communication groove 65. At the liquid flow path intersection 66, the liquid flow path mainstream groove 61 and the liquid flow path communication groove 65 communicate in a T-shape. This prevents the liquid flow path communication groove 65 on the other side (e.g., the lower side in FIG. 8) from communicating with the liquid flow path mainstream groove 61 at the liquid flow path intersection 66, where one liquid flow path mainstream groove 61 communicates with the liquid flow path communication groove 65 on one side (e.g., the upper side in FIG. 8). This prevents the wall surface 62 of the liquid flow path mainstream groove 61 from being cut out on both sides (the upper and lower sides in FIG. 8) at the liquid flow path intersection 66, leaving one side of the wall surface 62 intact. This allows capillary action to be imparted to the working fluid in the liquid flow path mainstream groove 61 at the liquid flow path intersection 66 as well, and prevents a decrease in the driving force of the working fluid 2b toward the evaporation region SR at the liquid flow path intersection 66.

[0069] Next, we will explain the frame body protrusions 70 provided on the frame body part 32. When viewed from the Z direction (thickness direction of the wick sheet 30) (in a plan view), the frame body part 32 has a plurality of frame body protrusions 70 formed in a convex shape toward the inside of the steam flow path part 50. That is, the frame body part 32 has a plurality of frame body protrusions 70 formed in a convex shape toward the inside of the steam flow path part 50 in a plan view, and the plurality of frame body protrusions 70 are provided at different positions from each other in a plan view.

[0070] 9 and 10 , the frame body protrusion 70 is formed in a convex shape toward the first steam passage 51 of the steam flow path section 50 in a plan view. In the present embodiment, the frame body protrusion 70 has a rectangular shape in a plan view. Furthermore, the frame body protrusions 70 are provided at different positions on the inner end portions 32 a, 32 b of the frame body section 32 in a plan view. In this embodiment, the frame protrusions 70 are arranged at equal intervals around the entire periphery of the inner ends 32a and 32b of the frame portion 32 in a plan view.

[0071] The multiple frame body protrusions 70 include first protrusions 71 provided on a pair of inner end portions 32a extending in the X direction of the frame body portion 32, and second protrusions 72 provided on a pair of inner end portions 32b extending in the Y direction of the frame body portion 32.

[0072] As shown in Fig. 9, the first protrusions 71 protrude in the Y direction toward the first steam passage 51 in a plan view, and are arranged side by side in the X direction. The first protrusions 71 may be arranged at equal intervals in the X direction. Furthermore, as shown in Fig. 10, the second protrusions 72 protrude in the X direction toward the first steam passage 51 in a plan view, and are arranged side by side in the Y direction. The second protrusions 72 may be arranged at equal intervals in the Y direction.

[0073] The frame body protrusions 70 (first protrusions 71 and second protrusions 72) are formed by etching the first main body surface 31a and the second main body surface 31b of the wick sheet 30 in an etching process described below. More specifically, as shown in FIG. 11 , when viewed in a cross section along the Z direction (a cross section viewed in the X direction in FIG. 9 ), the frame body protrusions 70 have a lower curved surface 70d (first curved surface) provided on one side in the Z direction (the lower side in FIG. 11 ) and an upper curved surface 70e (second curved surface) provided on the other side in the Z direction (the upper side in FIG. 11 ). The wall surface 53a of the lower steam flow path recess 53 described above includes this lower curved surface 70d, and the wall surface 54a of the upper steam flow path recess 54 described above includes this upper curved surface 70e. As indicated by the dashed lines in Fig. 11 , the inner end portions 32a, 32b of the frame portion 32 similarly have a lower curved surface 32d and an upper curved surface 32e. The wall surface 53a of the lower steam flow path recess 53 described above also includes this lower curved surface 32d, and the wall surface 54a of the upper steam flow path recess 54 described above also includes this upper curved surface 32e. The lower curved surface 70d of the frame body protrusion 70 is formed to protrude from the lower curved surfaces 32d of the inner end portions 32a, 32b toward the first steam passage 51. The upper curved surface 70e of the frame body protrusion 70 is formed to protrude from the upper curved surfaces 32e of the inner end portions 32a, 32b toward the first steam passage 51.

[0074] The lower curved surface 70d is formed in a concave shape on the first main body surface 31a by being etched from the first main body surface 31a of the wick sheet 30 in an etching process described below. As a result, the lower curved surface 70d is formed in a curved shape, as shown in Fig. 11. The lower curved surface 70d is curved in a shape that bulges toward the second main body surface 31b. Such a lower curved surface 70d defines a part (the lower half) of the frame body protrusion 70.

[0075] The upper curved surface 70e is formed in a concave shape on the second main body surface 31b by etching the second main body surface 31b of the wick sheet 30. As a result, the upper curved surface 70e is formed in a curved shape, as shown in Fig. 11. The upper curved surface 70e is curved in a shape that bulges toward the first main body surface 31a. Such an upper curved surface 70e defines a part (upper half) of the frame body protrusion 70.

[0076] As shown in FIG. 11 , a protrusion 70c is formed at the junction of the lower curved surface 70d and the upper curved surface 70e. The protrusion 70c protrudes into the first steam passage 51. When viewed in a cross section along the Z direction, the frame protrusion 70 has a lower end 70a of the lower curved surface 70d provided on the opposite side from the protrusion 70c, and an upper end 70b of the upper curved surface 70e provided on the opposite side from the protrusion 70c. When viewed in a cross section along the Z direction, the lower end 70a is the intersection of the lower curved surface 70d and the first main body surface 31a, and the upper end 70b is the intersection of the upper curved surface 70e and the second main body surface 31b. In this embodiment, the protrusion 70c is positioned closer to the inside of the first steam passage 51 than the lower end 70a (to the right in FIG. 11 ) and closer to the inside of the first steam passage 51 than the upper end 70b. The outline of the frame convex portion 70 (first convex portion 71) depicted in FIG. 9 corresponds to the outline of the protrusion 70c in plan view.

[0077] Although not shown, the cross section of the frame body protrusion 70 (first protrusion 71) when viewed from the Y direction in Fig. 9 also has a lower curved surface, an upper curved surface, and a protrusion, similar to Fig. 11. The cross section of the frame body protrusion 70 (second protrusion 72) in Fig. 10 is also similar to Fig. 11.

[0078] As shown in FIG. 9, the height h2 (dimension in the Y direction) of the first protrusion 71 may be greater than the surface roughness (arithmetic mean height Ra defined in JIS B 0601-2001) of the inner end portions 32a, 32b. The arithmetic mean height Ra may be measured using a scanning white light interferometer VertScan manufactured by Ryoka Systems Co., Ltd. The arithmetic mean height Ra of the inner end portions 32a, 32b may be, for example, 0.1 μm to 5 μm, and the height h2 of the first protrusion 71 may be, for example, 10 μm to 200 μm. Note that, as shown in FIG. 11, the height h2 of the first protrusion 71 is the dimension of the first protrusion 71 in the Y direction, and refers to the dimension at the position where the through portion 34 is located in the Z direction. Also, as shown in FIG. 9, the width w6 (dimension in the X direction) of the first protrusion 71 may be, for example, 100 μm to 1000 μm. The first protrusions 71 may have the same shape and dimensions as one another. 9, the interval p1 between one first protrusion 71 and another adjacent first protrusion 71 may be, for example, 100 μm to 1000 μm. That is, the first protrusions 71 may be arranged side by side in the X direction at an arrangement pitch of interval p1.

[0079] 10, the height h3 (dimension in the X direction) of the second protrusion 72 may be equal to the height h2 of the first protrusion 71. As shown in FIG. 10, the width w7 (dimension in the Y direction) of the second protrusion 72 may be equal to the width w6 of the first protrusion 71. The second protrusions 72 may have the same shape and dimensions as one another. As shown in FIG. 10, the spacing p2 between one second protrusion 72 and the adjacent second protrusion 72 may be equal to the spacing p1 between the first protrusions 71. That is, the second protrusions 72 may be arranged side by side in the second direction Y at the same arrangement pitch as the arrangement pitch of the first protrusions 71. In this way, the first protrusions 71 and the second protrusions 72 may have the same shape and dimensions as one another and be arranged at equal intervals around the entire circumference of the inner ends 32a, 32b of the frame body 32 in a plan view. However, the present invention is not limited to this, and the first protrusions 71 and the second protrusions 72 may have different shapes and dimensions. Furthermore, the first protrusions 71 and the second protrusions 72 may be arranged at different intervals.

[0080] The materials constituting the lower sheet 10, upper sheet 20, and wick sheet 30 are not particularly limited as long as they have good thermal conductivity. However, the lower sheet 10, upper sheet 20, and wick sheet 30 may contain, for example, copper or a copper alloy. In this case, the thermal conductivity of each sheet 10, 20, and 30 can be increased, thereby improving the heat dissipation efficiency of the vapor chamber 1. Furthermore, when pure water is used as the working fluids 2a and 2b, corrosion can be prevented. However, other metal materials such as aluminum and titanium, or other metal alloy materials such as stainless steel can also be used for these sheets 10, 20, and 30 as long as they can achieve the desired heat dissipation efficiency and prevent corrosion.

[0081] 3 may be, for example, 100 μm to 1000 μm. By making the thickness t1 of the vapor chamber 1 100 μm or more, the vapor channel section 50 can be appropriately secured, allowing the vapor chamber 1 to function appropriately. On the other hand, by making the thickness t1 1000 μm or less, the thickness t1 of the vapor chamber 1 can be prevented from becoming too thick.

[0082] The thickness t2 of the lower sheet 10 may be, for example, 6 μm to 100 μm. By setting the thickness t2 of the lower sheet 10 to 6 μm or more, the mechanical strength of the lower sheet 10 can be ensured. On the other hand, by setting the thickness t2 of the lower sheet 10 to 100 μm or less, the thickness t1 of the vapor chamber 1 can be prevented from becoming too thick. Similarly, the thickness t3 of the upper sheet 20 may be set to be the same as the thickness t2 of the lower sheet 10. The thickness t3 of the upper sheet 20 and the thickness t2 of the lower sheet 10 may be different.

[0083] The thickness t4 of the wick sheet 30 may be, for example, 50 μm to 400 μm. By making the thickness t4 of the wick sheet 30 50 μm or more, the vapor channel portion 50 can be properly secured, thereby enabling the wick sheet 30 to function properly as the vapor chamber 1. On the other hand, by making the thickness t4 400 μm or less, the thickness t1 of the vapor chamber 1 can be prevented from becoming too thick.

[0084] Next, a method for manufacturing the vapor chamber 1 of this embodiment configured as described above will be described with reference to Figures 12 to 14. Figures 12 to 14 show cross sections similar to the cross section of Figure 3.

[0085] First, the process of manufacturing the wick sheet 30 will be described.

[0086] First, as shown in FIG. 12, in a preparation step, a flat metal material sheet M including a first material surface Ma and a second material surface Mb is prepared.

[0087] After the preparation step, in the etching step, the metal material sheet M is etched from the first material surface Ma and the second material surface Mb, as shown in FIG. 13, to form the vapor flow path portion 50 and the liquid flow path portion 60.

[0088] More specifically, a patterned resist film (not shown) is formed on the first material surface Ma and the second material surface Mb of the metal material sheet M by photolithography. The pattern of this resist film includes the pattern of the frame convex portion 70 described above. Next, the first material surface Ma and the second material surface Mb of the metal material sheet M are etched through the openings in the patterned resist film. As a result, the first material surface Ma and the second material surface Mb of the metal material sheet M are etched in a pattern, forming the vapor flow path portion 50 and the liquid flow path portion 60 as shown in FIG. 13. The frame convex portion 70 is also formed by this etching. The etching solution may be, for example, an iron chloride-based etching solution such as an aqueous ferric chloride solution, or a copper chloride-based etching solution such as an aqueous copper chloride solution.

[0089] The etching may be performed simultaneously on the first material surface Ma and the second material surface Mb of the metal material sheet M. However, this is not limited to this, and the etching of the first material surface Ma and the second material surface Mb may be performed in separate steps. Furthermore, the vapor flow path portion 50 and the liquid flow path portion 60 may be formed by etching simultaneously, or may be formed in separate steps.

[0090] In the etching step, the first material surface Ma and the second material surface Mb of the metal material sheet M are etched to obtain a predetermined outer contour shape as shown in FIG. That is, the edge of the wick sheet 30 is formed.

[0091] In this manner, the wick sheet 30 according to this embodiment is obtained.

[0092] After the manufacturing process of the wick sheet 30, the lower sheet 10, the upper sheet 20, and the wick sheet 30 are joined together in a joining process as shown in Fig. 14. The lower sheet 10 and the upper sheet 20 may be formed from rolled material having a desired thickness.

[0093] More specifically, first, the lower sheet 10, the wick sheet 30, and the upper sheet 20 are laminated in this order. In this case, the first main body surface 31a of the wick sheet 30 is placed on the second lower sheet surface 10b of the lower sheet 10, and the first upper sheet surface 20a of the upper sheet 20 is placed on the second main body surface 31b of the wick sheet 30. At this time, the alignment holes 12 of the lower sheet 10, the alignment holes 35 of the wick sheet 30, and the alignment holes 22 of the upper sheet 20 are used to align the sheets 10, 20, and 30.

[0094] Next, the lower sheet 10, the wick sheet 30 and the upper sheet 20 are temporarily attached. For example, these sheets 10, 20, 30 may be temporarily joined by spot resistance welding, or these sheets 10, 20, 30 may be temporarily joined by laser welding.

[0095] Next, the lower sheet 10, the wick sheet 30, and the upper sheet 20 are permanently bonded together by diffusion bonding. Diffusion bonding involves closely bonding the lower sheet 10 and the wick sheet 30, and then applying pressure and heat in the stacking direction in a controlled atmosphere, such as a vacuum or an inert gas atmosphere, to bond them together by utilizing atomic diffusion at the bonding surfaces. Diffusion bonding involves heating the materials of the sheets 10, 20, and 30 to a temperature close to, but lower than, their melting points, thereby preventing the sheets 10, 20, and 30 from melting and deforming. More specifically, the first main body surface 31a of the frame portion 32 and each land portion 33 of the wick sheet 30 is diffusion bonded to the second lower sheet surface 10b of the lower sheet 10. Furthermore, the frame portion 32 of the wick sheet 30 and the second main body surface 31b of each land portion 33 are diffusion bonded to the first upper sheet surface 20a of the upper sheet 20. In this manner, the sheets 10, 20, 30 are diffusion bonded to form a sealed space 3 having a vapor flow path portion 50 and a liquid flow path portion 60 between the lower sheet 10 and the upper sheet 20. In the above-mentioned injection portion 4, the lower injection protrusion 11 of the lower sheet 10 and the wick sheet injection protrusion 36 of the wick sheet 30 are diffusion bonded, and the wick sheet injection protrusion 36 is diffusion bonded to the upper injection protrusion 21 of the upper sheet 20, forming a space with the injection flow path 37 closed.

[0096] After the joining step, the working fluid 2b is injected into the sealed space 3 from the injection section 4. At this time, the amount of the working fluid 2b injected may be greater than the total volume of the space formed by each liquid flow path main groove 61 and each liquid flow path communication groove 65 of the liquid flow path section 60.

[0097] Thereafter, the above-mentioned injection flow path 37 is sealed. For example, injection portion 4 may be irradiated with a laser beam to partially melt injection portion 4 and seal injection flow path 37. This blocks communication between sealed space 3 and the outside, seals working fluid 2b in sealed space 3, and prevents working fluid 2b in sealed space 3 from leaking to the outside. Note that injection flow path 37 can be sealed by caulking injection portion 4 (pressing to cause plastic deformation) or brazing.

[0098] In this manner, the vapor chamber 1 according to this embodiment is obtained.

[0099] Next, the method of operating the vapor chamber 1, that is, the method of cooling the device D, will be described.

[0100] The vapor chamber 1 obtained as described above is installed in a housing H of a mobile terminal or the like, and a device D, such as a CPU, which is a device to be cooled, is attached to the second upper sheet surface 20b of the upper sheet 20 (or the vapor chamber 1 is attached to the device D). Due to its surface tension, the working fluid 2b in the sealed space 3 adheres to the wall surfaces of the sealed space 3, i.e., the wall surface 53a of the lower vapor channel recess 53, the wall surface 54a of the upper vapor channel recess 54, the wall surface 62 of the liquid channel main groove 61 of the liquid channel section 60, and the wall surface of the liquid channel connecting groove 65. The working fluid 2b can also adhere to a portion of the second lower sheet surface 10b of the lower sheet 10 exposed to the lower vapor channel recess 53. The working fluid 2b can also adhere to a portion of the first upper sheet surface 20a of the upper sheet 20 exposed to the upper vapor channel recess 54, the liquid channel main groove 61, and the liquid channel connecting groove 65.

[0101] In this state, when the device D generates heat, the working fluid 2b present in the evaporation region SR (see FIG. 6) receives heat from the device D. The received heat is absorbed as latent heat, and the working fluid 2b evaporates (vaporizes), generating working vapor 2a. Most of the generated working vapor 2a diffuses within the lower vapor flow path recess 53 and the upper vapor flow path recess 54 that form the sealed space 3 (see the solid arrows in FIG. 6). The working vapor 2a in each vapor flow path recess 53, 54 leaves the evaporation region SR, and most of the working vapor 2a is transported to the condensation region CR (the right-hand portion in FIG. 6), which has a relatively low temperature. In the condensation region CR, the working vapor 2a is cooled by radiating heat mainly to the lower sheet 10. The heat received by the lower sheet 10 from the working vapor 2a is transferred to the outside air via the housing member Ha (see FIG. 3).

[0102] The working vapor 2a radiates heat to the lower sheet 10 in the condensation region CR, thereby losing the absorbed latent heat and condensing in the evaporation region SR, generating working fluid 2b. The generated working fluid 2b adheres to the wall surfaces 53a, 54a of the vapor flow path recesses 53, 54, the second lower sheet surface 10b of the lower sheet 10, and the first upper sheet surface 20a of the upper sheet 20. Because the working fluid 2b continues to evaporate in the evaporation region SR, the working fluid 2b in the liquid flow path section 60 other than the evaporation region SR (i.e., the condensation region CR) is transported toward the evaporation region SR by capillary action of the liquid flow path mainstream grooves 61 (see the dashed arrows in FIG. 6). As a result, the working fluid 2b adhering to the wall surfaces 53a, 54a, the second lower sheet surface 10b, and the first upper sheet surface 20a moves to the liquid flow path section 60, passes through the liquid flow path connecting grooves 65, and enters the liquid flow path mainstream grooves 61. In this way, the working fluid 2b is filled into each liquid flow path mainstream groove 61 and each liquid flow path connecting groove 65. Therefore, the filled working fluid 2b obtains a driving force toward the evaporation region SR due to the capillary action of each liquid flow path mainstream groove 61, and is smoothly transported toward the evaporation region SR.

[0103] In the liquid flow path section 60, each liquid flow path mainstream groove 61 communicates with the adjacent other liquid flow path mainstream groove 61 via the corresponding liquid flow path connection groove 65. This allows the working fluid 2b to flow back and forth between the adjacent liquid flow path mainstream grooves 61, preventing dryout in the liquid flow path mainstream grooves 61. As a result, capillary action is imparted to the working fluid 2b in each liquid flow path mainstream groove 61, and the working fluid 2b is transported smoothly toward the evaporation region SR.

[0104] The working fluid 2b that reaches the evaporation region SR receives heat from the device D again and evaporates. The working vapor 2a that has evaporated from the working fluid 2b passes through the liquid flow path connecting groove 65 in the evaporation region SR, moves to the lower vapor flow path recess 53 and the upper vapor flow path recess 54, which have large flow path cross-sectional areas, and diffuses within each of the vapor flow path recesses 53, 54. In this way, the working fluids 2a, 2b circulate within the sealed space 3 while repeatedly changing phases, i.e., evaporating and condensing, and transport and release heat from the device D. As a result, the device D is cooled.

[0105] The working fluid 2b generated by condensing the working vapor 2a fills and remains in the liquid flow path main groove 61 and the liquid flow path connecting groove 65 of the liquid flow path section 60. However, in general, some of the working fluid 2b does not fill these grooves, and instead may adhere to the wall surface 53a of the lower steam flow path recess 53 and the wall surface 54a of the upper steam flow path recess 54 due to surface tension. That is, some of the working fluid 2b may adhere to the inner end portions 32a and 32b of the frame section 32.

[0106] In contrast, in the present embodiment, frame protrusions 70 are provided on the inner end portions 32a, 32b of the frame portion 32. This increases the contact area between the hydraulic fluid 2b and the frame portion 32. This allows the hydraulic fluid 2b to wet and spread throughout the frame portion 32. As a result, the hydraulic fluid 2b can wet, spread, and disperse at the inner end portions 32a, 32b of the frame portion 32, preventing the hydraulic fluid 2b from remaining concentrated in a specific area.

[0107] When the electronic device E equipped with the vapor chamber 1 is placed in an environment with a temperature lower than the freezing point of the working fluids 2a and 2b, the working fluid 2b adhering to the inner ends 32a and 32b of the frame body 32 may freeze. Even in such a case, the working fluid 2b is dispersed at the inner ends 32a and 32b of the frame body 32, preventing the frozen working fluid 2b from blocking the first vapor passage 51 of the vapor flow path 50. This prevents the flow of the working vapor 2a in the first vapor passage 51 from being hindered by the freezing of the working fluid 2b, thereby preventing a decrease in performance of the vapor chamber 1.

[0108] According to this embodiment, the frame 32 has a plurality of frame protrusions 70 formed in a convex shape toward the inside of the vapor flow path 50 in a plan view. This increases the contact area between the working fluid 2b and the frame 32. This allows the working fluid 2b to spread across the frame 32. Therefore, the working fluid 2b spreads and disperses at the inner ends 32a and 32b of the frame 32, preventing it from remaining concentrated in a specific area. Even if the electronic device E equipped with the vapor chamber 1 is placed in a temperature environment below the freezing point of the working fluids 2a and 2b and the working fluid 2b attached to the inner ends 32a and 32b of the frame 32 freezes, the frozen working fluid 2b can prevent the vapor flow path 50 from being blocked. As a result, performance degradation of the vapor chamber 1 can be prevented.

[0109] Furthermore, according to this embodiment, the multiple frame protrusions 70 include first protrusions 71 provided on a pair of inner end portions 32a extending in the X direction. This allows the working fluid 2b to spread and disperse in the direction in which the land portion 33 extends, i.e., the direction in which the working vapor 2a flows. This prevents the frozen working fluid 2b from blocking the vapor passage in the vapor flow path 50, which extends in the direction in which the working vapor 2a flows. In this embodiment, an evaporation region SR is provided on one side in the direction in which the land portion 33 extends, and a condensation region CR is provided on the other side. This allows the working fluid 2b adhering to the condensation region CR to spread and disperse toward the evaporation region SR. This prevents the working fluid 2b from freezing unevenly toward the condensation region CR, and prevents the vapor flow path 50 from being blocked by the frozen working fluid 2b. This effectively prevents performance degradation of the vapor chamber 1.

[0110] Furthermore, according to this embodiment, the multiple frame protrusions 70 include second protrusions 72 provided on a pair of inner end portions 32b extending in the Y direction. This allows the working fluid 2b to wet, spread, and disperse in the Y direction as well. This further prevents the vapor flow path portion 50 from being blocked by frozen working fluid 2b.

[0111] Furthermore, according to this embodiment, when viewed in a cross section along the Z direction, the frame protrusion 70 has a lower curved surface 70d provided on one side in the Z direction and an upper curved surface 70e provided on the other side in the Z direction. As such, the frame protrusion 70 has multiple curved surfaces, which further increases the contact area between the working fluid 2b and the frame 32 and allows the working fluid 2b to further spread across the frame 32. This further prevents the vapor flow path 50 from being blocked by frozen working fluid 2b.

[0112] Furthermore, according to this embodiment, when viewed in a cross section along the Z direction, the protrusion 70c is positioned more inward in the first vapor passage 51 than the lower end 70a, and more inward in the first vapor passage 51 than the upper end 70b. Such protrusion 70c can be formed by etching from the first body surface 31a and the second body surface 31b in an etching process. Etching from the first body surface 31a and etching from the second body surface 31b can be performed simultaneously. This reduces the number of etching processes, thereby improving the manufacturing efficiency of the vapor chamber 1.

[0113] Furthermore, according to this embodiment, working fluids 2a and 2b having freeze-expansion properties are sealed in the vapor chamber 1. If the working fluids 2a and 2b having freeze-expansion properties freeze in the vapor flow path portion 50, the force caused by the expansion may be received by the lower sheet 10 and the upper sheet 20, causing deformation of the vapor chamber 1. In contrast, according to this embodiment, the working fluid 2b can be wetted and spread and dispersed at the inner ends 32a and 32b of the frame portion 32. As a result, even if the working fluid 2b expands due to freezing, the force caused by the expansion can be prevented from acting on the lower sheet 10 and the upper sheet 20. This prevents deformation of the vapor chamber 1.

[0114] (First Modification) In the above-described embodiment, an example has been described in which the frame body protrusions 70 have a rectangular shape in a plan view (see FIGS. 9 and 10 ). However, this is not limited thereto, and the frame body protrusions 70 may have any shape as long as they are formed in a convex shape toward the steam flow path 50. For example, as shown in FIG. 15 , the frame body protrusions 70 may have a triangular shape in a plan view. Furthermore, for example, the frame body protrusions 70 may have a curved shape, such as a semicircular shape, a semielliptical shape, or a wavy shape, in a plan view. FIG. 16 shows an example in which the frame body protrusions 70 have a semicircular shape. In such a case, the dimensions of the frame body protrusions 70 may be approximately the same as the dimensions of the frame body protrusions 70 in the above-described embodiment. Furthermore, the arrangement pitch of the frame body protrusions 70 may also be approximately the same as the arrangement pitch of the frame body protrusions 70 in the above-described embodiment.

[0115] In the first modified example, the frame protrusion 70 also increases the contact area between the working fluid 2b and the frame portion 32, allowing the working fluid 2b to wet and spread across the frame portion 32. Therefore, even if the working fluid 2b freezes, the vapor flow path portion 50 can be prevented from being blocked by the frozen working fluid 2b, and a decrease in performance of the vapor chamber 1 can be suppressed.

[0116] (Second Modification) In the above-described embodiment, an example has been described in which the protrusion 70c of the frame convex portion 70 is positioned more inward (to the right in FIG. 11) in the first steam passage 51 than the lower end 70a, and more inward than the upper end 70b in the first steam passage 51 (see FIG. 11). However, this is not limiting, and the lower end 70a or the upper end 70b may be positioned more inward in the first steam passage 51 than the protrusion 70c.

[0117] 17, the protrusion 70c may protrude closer to the first vapor passage 51 than the lower end 70a, and the upper end 70b may be located closer to the first vapor passage 51 than the protrusion 70c. In this case, the frame protrusion 70 may be formed by etching only from the first main body surface 31a of the wick sheet 30. For example, the frame protrusion 70 may be formed by performing two etching processes starting from the first main body surface 31a of the wick sheet 30. That is, in the first etching process, a resist film on the first main body surface 31a is patterned to have a shape corresponding to the lower vapor passage recess 53, and the first material surface Ma of the metal material sheet M is etched through the openings in the resist film. In the second etching step, a new resist film is formed on the first body surface 31a and the wall surface 53a of the lower steam flow path recess 53, and the resist film is patterned to have a shape corresponding to the upper steam flow path recess 54. The wall surface 53a of the lower steam flow path recess 53 is etched through the openings in the resist film. In this case, the wall surface 53a of the lower steam flow path recess 53 and the wall surface 54a of the upper steam flow path recess 54 are connected to form the through-portion 34, but the position where the planar area of ​​the steam flow path section 50 is smallest is not the position of the through-portion 34 but the position where the upper end 70b is located in the Z direction. In this case, the outline of the frame-body protrusion 70 depicted in FIGS. 9 and 10 corresponds to the outline of the upper end 70b in a plan view.

[0118] 18, the protrusion 70c may be positioned closer to the inside of the first steam passage 51 than the upper end 70b, and the lower end 70a may be positioned closer to the inside of the first steam passage 51 than the protrusion 70c. In this case, the frame protrusion 70 may be formed by etching only the second main body surface 31b of the wick sheet 30. For example, the frame protrusion 70 may be formed by performing two etching processes from the second main body surface 31b of the wick sheet 30, as in the example shown in FIG. 17. In this case, the position where the planar area of ​​the steam channel section 50 is smallest is not the position of the through-hole 34, but the position where the lower end 70a is located in the Z direction. In this case, the outline of the frame protrusion 70 depicted in FIGS. 9 and 10 corresponds to the outline of the lower end 70a in a plan view.

[0119] When the frame body protrusion 70 having the shape shown in Figures 17 and 18 is formed by the above-mentioned etching process, the wall surface 53a of the lower steam flow path recess 53 and the wall surface 54a of the upper steam flow path recess 54 in the parts other than the frame body protrusion 70 may also be formed to have a similar shape.

[0120] In the second modified example, the frame protrusion 70 also increases the contact area between the working fluid 2b and the frame 32, allowing the working fluid 2b to wet and spread across the frame 32. Furthermore, according to the second modified example, the amount by which the protrusion 70c protrudes inward into the first vapor passage 51 can be reduced. This increases the width of the first vapor passage 51 at the protrusion 70c, thereby increasing the space within the first vapor passage 51. Therefore, even if the working fluid 2b freezes, the vapor flow path 50 can be further prevented from being blocked by the frozen working fluid 2b, and deterioration in performance of the vapor chamber 1 can be further suppressed.

[0121] Furthermore, the multiple frame body protrusions 70 may include a frame body protrusion 70 as shown in Fig. 17 described above and a frame body protrusion 70 as shown in Fig. 18 described above. Here, the frame body protrusion 70 as shown in Fig. 17 will be referred to as an upper end side protrusion 74 (second end side protrusion), and the frame body protrusion 70 as shown in Fig. 18 will be referred to as a lower end side protrusion 73 (first end side protrusion). In this case, in the lower end side protrusion 73, as shown in Fig. 18, the protrusion 70c is positioned more inward in the first steam passage 51 than the upper end 70b, and the lower end 70a is positioned more inward in the first steam passage 51 than the protrusion 70c. As shown in FIG. 17 , in the upper end portion 74, the protrusion 70c is positioned more inward of the first steam passage 51 than the lower end portion 70a, and the upper end portion 70b is positioned more inward of the first steam passage 51 than the protrusion 70c. In plan view, the lower end portion 73 and the upper end portion 74 may be arranged alternately. For example, as shown in FIG. 9 , in each inner end portion 32a extending in the X direction, the lower end portion 73 and the upper end portion 74 may be arranged alternately in the X direction. That is, the multiple first protrusions 71 may include lower end portion 73 and upper end portion 74 arranged alternately in the X direction. Furthermore, as shown in FIG. 10 , in each inner end portion 32b extending in the Y direction, the lower end portion 73 and the upper end portion 74 may be arranged alternately in the Y direction. That is, the plurality of second protrusions 72 may include lower end protrusions 73 and upper end protrusions 74 arranged alternately in the Y direction.

[0122] In this way, by alternately arranging the frame protrusions 70 having different shapes in the Z direction, the working fluid 2b can be more easily spread in the frame portion 32. Therefore, even if the working fluid 2b freezes, the vapor flow path portion 50 can be more effectively prevented from being blocked by the frozen working fluid 2b, and the performance degradation of the vapor chamber 1 can be more effectively prevented.

[0123] (Third Modification) In the above-described embodiment, an example has been described in which the frame protrusions 70 are provided on each of the pair of inner end portions 32a extending in the X direction and the pair of inner end portions 32b extending in the Y direction (see FIG. 6). However, this is not limiting, and the frame protrusions 70 may be provided on one or more of the inner end portions 32a, 32b of the frame portion 32.

[0124] For example, the frame body protrusion 70 may be provided on one of the pair of inner end portions 32a extending in the X direction, and may not be provided on either of the pair of inner end portions 32b extending in the Y direction. Also, for example, the frame body protrusion 70 may be provided on each of the pair of inner end portions 32a extending in the X direction, and may not be provided on either of the pair of inner end portions 32b extending in the Y direction. Also, for example, the frame body protrusion 70 may be provided on each of the pair of inner end portions 32a extending in the X direction, and may be provided on either of the pair of inner end portions 32b extending in the Y direction.

[0125] In the third modified example, the frame protrusion 70 also increases the contact area between the working fluid 2b and the frame portion 32, allowing the working fluid 2b to wet and spread across the frame portion 32. Therefore, even if the working fluid 2b freezes, the vapor flow path portion 50 can be prevented from being blocked by the frozen working fluid 2b, and a decrease in performance of the vapor chamber 1 can be suppressed.

[0126] (Fourth Modification) In the above-described embodiment, an example has been described in which the frame body protrusions 70 are arranged around the entire periphery of the inner end portions 32a, 32b of the frame body portion 32 in a plan view (see FIG. 6). However, this is not limiting, and the frame body protrusions 70 may be arranged only in a partial region of the inner end portions 32a, 32b of the frame body portion 32. Furthermore, the frame body protrusions 70 may not be arranged in other regions.

[0127] For example, as shown in Fig. 19, the frame protrusion 70 may be provided in the condensation region CR. That is, when the evaporation region SR is provided on one side in the X direction of the vapor chamber 1 (the left side in Fig. 19), the frame protrusion 70 may be provided only on the other side in the X direction of the vapor chamber 1 (the right side in Fig. 19). More specifically, the frame protrusion 70 may be provided on the portion of the inner end 32a on the condensation region CR side (the right half in Fig. 19) and on the condensation region CR side of the pair of inner end portions 32b (the right side in Fig. 19), but may not be provided on the portion of the inner end 32a on the evaporation region SR side (the left half in Fig. 19) and on the evaporation region SR side of the pair of inner end portions 32b (the left side in Fig. 19).

[0128] As described above, the working fluid 2b is produced in the condensation region CR and evaporated in the evaporation region SR. Therefore, the working fluid 2b is particularly likely to adhere to the inner ends 32a, 32b of the frame 32 on the condensation region CR side rather than the evaporation region SR. By providing the frame protrusions 70 on the condensation region CR side rather than the evaporation region SR, as in the fourth modification, the working fluid 2b adhering to the condensation region CR side can be allowed to wet and spread toward the evaporation region SR side. This prevents the working fluid 2b from freezing unevenly toward the condensation region CR side, and prevents the frozen working fluid 2b from blocking the vapor flow path 50. As a result, performance degradation of the vapor chamber 1 can be effectively suppressed. Furthermore, by limiting the provision of the frame protrusions 70 on the evaporation region SR side, the flow of the working vapor 2a on the evaporation region SR side can be smoothed. That is, the working vapor 2a can be smoothly transported from the evaporation region SR to the condensation region CR. This prevents performance degradation of the vapor chamber 1. Furthermore, by limiting the provision of the frame protrusions 70, the vapor chamber 1 can be easily manufactured. Therefore, an increase in the manufacturing cost of the vapor chamber 1 can be suppressed.

[0129] The present invention is not limited to the above-described embodiments and modifications, and can be embodied by modifying the components within the scope of the gist of the present invention. Furthermore, various inventions can be created by appropriately combining the multiple components disclosed in the above-described embodiments and modifications. Some components may be omitted from all the components shown in the above-described embodiments and modifications. [Explanation of symbols]

[0130] 1 Vapor chamber 2a Working steam 2b Hydraulic fluid 10 Lower seat 20 Upper seat 30 Wick Sheet 32 Frame body part 33 Land Department 50 Steam flow path section 60 Liquid flow path section 70 Frame protrusion 70a Lower end 70b Upper end 70c protrusion 70d lower curved surface 70e Upper curved surface 71 First convex part 72 Second convex part 73 Lower end side protrusion 74 Upper end side convex part SR evaporation region CR condensation region D Device E-electronic equipment H Housing

Claims

1. A wick sheet for a vapor chamber used in a vapor chamber in which a working fluid is sealed in a sealed space, a frame portion defining the sealed space; a land portion provided within the frame portion; a vapor flow path portion provided between the frame portion and the land portion, through which vapor of the working fluid passes; a liquid flow path portion provided in the land portion, communicating with the vapor flow path portion, through which the liquid working fluid passes, the frame portion has a frame protrusion formed in a convex shape toward the inside of the steam flow path portion in a plan view, the frame protrusion faces the land portion, A wick sheet for a vapor chamber, wherein, in a plan view, the width of the vapor flow path portion at a position where the frame body convex portion is not present is greater than the width of the vapor flow path portion at a position where the frame body convex portion is present.

2. A wick sheet for a vapor chamber used in a vapor chamber in which a working fluid is sealed in a sealed space, a frame portion defining the sealed space; a land portion provided within the frame portion; a vapor flow path portion provided between the frame portion and the land portion, through which vapor of the working fluid passes; a liquid flow path portion provided in the land portion, communicating with the vapor flow path portion, through which the liquid working fluid passes, the frame portion has a frame protrusion formed in a convex shape toward the inside of the steam flow path portion in a plan view, A wick sheet for a vapor chamber, wherein the frame protrusion is arranged in a partial area of ​​the frame.

3. A wick sheet for a vapor chamber used in a vapor chamber in which a working fluid is sealed in a sealed space, a frame portion defining the sealed space; a land portion provided within the frame portion; a seat space provided between the frame portion and the land portion; a groove portion provided in the land portion and communicating with the seat space, the frame portion has a frame protrusion formed in a convex shape toward the seat space in a plan view, the frame protrusion faces the land portion, A wick sheet for a vapor chamber, wherein, in a plan view, the width of the sheet space at a position where the frame protrusion is not present is greater than the width of the sheet space at a position where the frame protrusion is present.

4. A wick sheet for a vapor chamber used in a vapor chamber in which a working fluid is sealed in a sealed space, a frame portion defining the sealed space; a land portion provided within the frame portion; a seat space provided between the frame portion and the land portion; a groove portion provided in the land portion and communicating with the seat space, the frame portion has a frame protrusion formed in a convex shape toward the seat space in a plan view, A wick sheet for a vapor chamber, wherein the frame protrusion is arranged in a partial area of ​​the frame.

5. 3. A wick sheet for a vapor chamber as described in claim 1 or 2, wherein, when viewed in a cross section along the thickness direction of the wick sheet, the frame convex portion has a first curved surface provided on one side in the thickness direction, a second curved surface provided on the other side in the thickness direction, and a protrusion where the first curved surface and the second curved surface meet and protrude into the vapor flow path portion.

6. A wick sheet for a vapor chamber as described in claim 3 or 4, wherein when viewed in a cross section along the thickness direction of the wick sheet, the frame convex portion has a first curved surface provided on one side in the thickness direction, a second curved surface provided on the other side in the thickness direction, and a protrusion where the first curved surface and the second curved surface meet and protrude into the sheet space.

7. a condensation region in which the working fluid condenses; an evaporation region in which the working fluid evaporates; The wick sheet for a vapor chamber according to claim 1 , wherein the frame protrusion is provided in the condensation region.

8. The wick sheet for a vapor chamber according to claim 1 , wherein the land portion has a longitudinal direction aligned with a first direction.

9. The wick sheet for a vapor chamber according to claim 1 , wherein the frame protrusion has a rectangular shape, a triangular shape, or a curved shape in a plan view.

10. A vapor chamber comprising a wick sheet for a vapor chamber according to any one of claims 1 to 9.

11. An electronic device comprising the vapor chamber according to claim 10.

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