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 mobile terminals and tablet terminals, are cooled by heat dissipation members such as heat pipes (see, for example, Patent Document 1). In recent years, there has been a demand for thinner heat dissipation members in order to make mobile terminals thinner, and vapor chambers that 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 diffuses the heat of the device, thereby cooling the device.

[0003] More specifically, the working fluid in the vapor chamber receives heat from the device in a portion (evaporation section) close to the device and evaporates to become vapor (working vapor). The working vapor diffuses in the vapor passage section in a direction away from the evaporation section, is cooled, and condenses to become liquid. A liquid passage section having a capillary structure (wick) is provided in the vapor chamber, and the working fluid (working liquid) that has condensed to become liquid enters the liquid passage section from the vapor passage section and flows through the liquid passage section to be transported toward the evaporation section. The working liquid then receives heat again in the evaporation section and evaporates. In this way, the working fluid circulates through the vapor chamber while repeatedly changing phases, that is, evaporating and condensing, thereby transferring heat from the device and increasing the heat dissipation efficiency. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2008-82698 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in a temperature environment lower than the freezing point of the working fluid sealed in the vapor chamber, the working fluid may freeze. In this case, the frozen working fluid may block a part of the vapor passage in the vapor chamber, which may degrade 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 of the performance of the vapor chamber. [Means for solving the problem]

[0007] The present invention relates to A wick sheet for a vapor chamber, which is interposed between a first sheet and a second sheet of the vapor chamber in which a working fluid is sealed, A frame portion, A land portion provided within the frame portion; a steam flow passage portion through which the working fluid vapor passes, the steam flow passage portion being provided between the frame portion and the land portion; 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, the frame portion having 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 above-mentioned wick sheet for a vapor chamber, The plurality of frame 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 portion. This may be done.

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

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

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

[0012] In addition, in the above-mentioned wick sheet for the vapor chamber, 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 above-mentioned wick sheet for the vapor chamber, When viewed in a cross section along the thickness direction, the protrusion is positioned more inward of the steam flow path 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 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 above-mentioned wick sheet for the vapor chamber, When viewed in a cross section along the thickness direction, the protrusion is positioned more inward of the steam flow path 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 than the protrusion. This may be done.

[0015] In addition, in the above-mentioned wick sheet for the vapor chamber, 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 portion is positioned more inward of the steam flow path portion than the first end portion, and the second end portion is positioned more inward of the steam flow path portion than the protrusion portion. This may be done.

[0016] The present invention also provides a method for producing a semiconductor device comprising the steps of: A wick sheet for a vapor chamber, which is interposed between a first sheet and a second sheet of the vapor chamber in which a working fluid is sealed, A frame portion, A land portion provided within the frame portion; a seat space provided between the frame portion and the land portion; A groove portion is provided in the land portion and communicates with the seat space, a wick sheet for a vapor chamber, the frame portion having a plurality of frame protrusions formed in a convex shape toward an inside of the sheet space in a plan view; to provide.

[0017] The present invention also provides a method for producing a semiconductor device comprising the steps of: The first sheet, A second sheet; A vapor chamber including the above-mentioned wick sheet for the vapor chamber, the wick sheet being 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 is condensed; an evaporation area 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 a method for producing a semiconductor device comprising the steps of: Housing and a device contained within the housing; and and a vapor chamber as described above in thermal contact with the device. Effect of the Invention

[0021] According to the present invention, the deterioration of the performance of the vapor chamber can be suppressed. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic perspective view illustrating an electronic device according to an embodiment. [Diagram 2] FIG. 2 is a top view showing a vapor chamber according to an embodiment. [Diagram 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. [Diagram 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 a partially enlarged cross-sectional view 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 portion shown in FIG. [Figure 10] 10 is a partially enlarged top view showing a second protrusion provided on the frame portion shown in 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 preparing 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 modified example 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 modified example of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to this specification, the scale and the aspect ratio are appropriately changed and exaggerated from those of the actual objects for the convenience of illustration and understanding.

[0024] In addition, terms such as "parallel," "orthogonal," and "same," which specify the shape, geometric conditions, and physical characteristics and their degree, as well as the length, angle, and physical characteristic values ​​used in this specification, are to be interpreted without being bound by strict meanings, but including the range in which similar functions can be expected. Furthermore, in the drawings, the shapes of multiple parts that can be expected to have similar functions are regularly depicted for clarity, but the shapes of the parts may be different from each other within the range in which the functions can be expected without being bound by strict meanings. In addition, in the drawings, the boundary lines indicating the joint surfaces between members are shown as simple straight lines for convenience, but the shape of the boundary line is not limited to being a strict straight line, and is arbitrary within the range in which the desired joint performance can be expected.

[0025] 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 with reference to Figs. 1 to 14. The vapor chamber 1 according to this embodiment is a device mounted on an electronic device E in order to cool a device D as a heat generating body housed in the electronic device E. Examples of the 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] Here, first, an electronic device E equipped with the vapor chamber 1 according to the present embodiment will be described by taking a tablet terminal as an example. As shown in FIG. 1, the electronic device E (tablet terminal) includes a housing H, a device D accommodated 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 accommodated 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 used. The heat received by the vapor chamber 1 is released to the outside of the vapor chamber 1 via the working fluids 2a and 2b 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, the vapor chamber 1 according to the present embodiment will be described. As shown in FIG. 2 and FIG. 3, the vapor chamber 1 has a sealed space 3 in which the working fluids 2a and 2b are sealed, and is configured to effectively cool the device D of the electronic device E described above by repeating phase changes 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, and mixtures thereof. The working fluids 2a and 2b may have a freezing expansion property. That is, the working fluids 2a and 2b may be fluids that expand when frozen. Examples of the working fluids 2a and 2b that have a freezing expansion property include pure water, or an aqueous solution of pure water to which an additive such as alcohol is 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. In the vapor chamber 1 according to this embodiment, the lower sheet 10, the wick sheet 30, and the upper sheet 20 are laminated in this order.

[0029] The vapor chamber 1 is generally formed in a thin flat plate shape. The planar shape of the vapor chamber 1 is arbitrary, but 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 being 1 cm and the other side being 3 cm, or a square with one side being 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. In addition, 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 a region that overlaps with the device D in a planar view, and is a region where the device D is attached. The evaporation region SR can be disposed at any location in the vapor chamber 1. In this embodiment, the evaporation region SR is formed on one side in the X direction of the vapor chamber 1 (the left side in FIG. 2). Heat from the device D is transferred to the evaporation region SR, and this heat causes the liquid working fluid (suitably referred to as working liquid 2b) to evaporate in the evaporation region SR. The heat from the device D can be transferred not only to the region that overlaps with the device D in a planar view, but also to the periphery of that region. For this reason, the evaporation region SR includes the region that overlaps with the device D in a planar view and the periphery of that region. Here, a planar view refers to a state in which the vapor chamber 1 is viewed 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), and corresponds to, for example, the state in which the vapor chamber 1 is viewed from above or below, as shown in Figure 2.

[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 (suitably referred to as working vapor 2a) mainly 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 in the X direction of the vapor chamber 1 (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 attitude of the mobile terminal. However, in this embodiment, for convenience, the sheet that receives heat from the device D is referred to as the above-mentioned upper sheet 20, and the sheet that dissipates the received heat is referred to as the above-mentioned lower sheet 10. For this reason, the following description will be given with the lower sheet 10 disposed on the lower side and the upper sheet 20 disposed 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 to the wick sheet 30, and a second lower sheet surface 10b provided on the side opposite to the first lower sheet surface 10a (i.e., the side of the wick sheet 30). The lower sheet 10 may be formed flat overall, or may have a constant thickness overall. A housing member Ha constituting a part of a housing H of a mobile terminal or the like is attached to the first lower sheet surface 10a. The first lower sheet surface 10a may be entirely covered with the housing member Ha. As shown in FIG. 4, alignment holes 12 may be provided at 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 flat overall, or may have a constant thickness overall. The above-mentioned device D is attached to this second upper sheet surface 20b. As shown in Fig. 5, alignment holes 22 may be provided at the four corners of the upper sheet 20.

[0036] 3, the wick sheet 30 includes a sheet body 31 and a steam 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 lower sheet 10 side, and the second body surface 31b is disposed on the upper sheet 20 side.

[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 can be permanently bonded, instead of diffusion bonding. The term "permanently bonded" is not limited to a strict meaning, and is used as a term to mean that the bond between the lower sheet 10 and the wick sheet 30 can be maintained to a degree that the sealing property of the sealed space 3 can be maintained during the operation of the vapor chamber 1, and that the bond between the upper sheet 20 and the wick sheet 30 can be maintained.

[0038] 3 and 6, the sheet body 31 of the wick sheet 30 according to this embodiment has a frame portion 32 formed in a rectangular frame shape 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 in a rectangular frame shape in a plan view. A steam flow path portion 50 is defined inside the frame portion 32. That is, inside the frame portion 32, the working steam 2a flows around the land portion 33. The frame portion 32 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 and 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 portion 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 portion 33 may be an elongated rectangular shape. Moreover, each land portion 33 may be arranged parallel to each other at equal intervals in the Y direction (second direction, up-down direction in FIG. 6). The working steam 2a is configured to flow around each land portion 33 and be transported toward the condensation region CR. This suppresses the flow of the working steam 2a from being obstructed. The width w1 of the land portion 33 (see FIG. 7) may be, for example, 100 μm to 1500 μm. Here, the width w1 of the land portion 33 is the dimension of the land portion 33 in the Y direction, and means the dimension at the position where the penetration portion 34 described later exists in the Z direction (thickness direction of the wick sheet 30).

[0041] The frame portion 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 below 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 portion 32 and each land portion 33.

[0042] The steam flow passage portion 50 is a flow passage through which the working steam 2a mainly passes. The steam flow passage portion 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 passage 51 and a plurality of second steam passages 52. The first steam passage 51 is formed between the frame body section 32 and the land section 33. The first steam passage 51 is formed inside the frame body section 32 and continuously outside the land section 33. The first steam passage 51 has a planar shape of a rectangular frame. The second steam passage 52 is formed between the adjacent land sections 33. The second steam passage 52 has a planar shape of an elongated rectangle. The steam flow path section 50 is divided into the first steam passage 51 and the plurality of second steam passages 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 passage recess 53 provided in the first main body surface 31a and an upper steam passage recess 54 provided in the second main body surface 31b. The lower steam passage recess 53 and the upper steam passage recess 54 are in communication with each other, and the first steam passage 51 and the second steam passage 52 of the steam passage 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 wall surface 53a formed in a curved shape, as shown in Fig. 7. This 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. Such a 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 wall surface 54a formed in a curved shape, 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 passage 51 and a part (upper half) of the second steam passage 52.

[0047] As shown in FIG. 7, the wall surface 53a of the lower steam passage recess 53 and the wall surface 54a of the upper steam passage recess 54 are connected to each other to form the through-portion 34. The wall surface 53a and the wall surface 54a are curved toward the through-portion 34. As a result, the lower steam passage recess 53 and the upper steam passage recess 54 are connected to each other. In this embodiment, the planar shape of the through-portion 34 in the first steam passage 51 is a rectangular frame shape similar to the first steam passage 51, and the planar shape of the through-portion 34 in the second steam passage 52 is an elongated rectangular shape similar to the second steam passage 52. The through-portion 34 may be defined by a ridge line formed by joining the wall surface 53a of the lower steam passage recess 53 and the wall surface 54a of the upper steam passage recess 54 and projecting inward. The planar area of ​​the steam passage portion 50 is minimum 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. Moreover, 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 a 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 20 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 communicate 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-portion 34 defined by a ridge line formed to protrude inward, but are 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 or rectangular, or may be 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 to allow the working steam 2a to pass therethrough.

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

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

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

[0054] 2, the vapor chamber 1 may further include an injection part 4 for injecting the working fluid 2b into the sealed space 3 at one edge in the X direction. 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 have 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 body 31 of the wick sheet 30. Among them, an injection flow path 37 is formed in the wick sheet injection protrusion 36. This injection flow path 37 extends from the first body surface 31a to the second body surface 31b of the sheet body 31, and penetrates the sheet body 31 (wick sheet injection protrusion 36) in the Z direction. In addition, the injection flow path 37 communicates with the steam 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 communicated with the liquid flow path section 60. The upper and lower surfaces of the wick sheet injection protrusion 36 are formed flat, and the upper surface of the lower injection protrusion 11 and the lower surface of the upper injection protrusion 21 are also formed flat. The planar shapes of the injection protrusions 11, 21, and 36 may be the same.

[0056] In this embodiment, the injection part 4 is provided at one edge of a pair of edges in the X direction of the vapor chamber 1, but the present invention is not limited to this and the injection part 4 can be provided at any position. Also, 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 the working liquid 2b can be injected. In this case, the injection flow path 37 communicating with the vapor flow path part 50 can be formed by etching only from 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 FIG. 3, FIG. 6 and FIG. 7, the second main body surface 31b of the sheet body 31 of the wick sheet 30 is provided with a liquid flow path portion 60 (groove portion) through which mainly the working fluid 2b passes. This liquid flow path portion 60 constitutes a part of the above-mentioned sealed space 3 and communicates with 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 connection grooves 65 which communicate with the liquid flow path main grooves 61.

[0059] Each liquid flow path mainstream groove 61 is formed to extend in the X direction as shown in Fig. 8. The 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 disposed at equal intervals in the Y direction.

[0060] The liquid flow path mainstream groove 61 is 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 mainstream groove 61 has a wall surface 62 formed in a curved shape, as shown in Fig. 7. This wall surface 62 defines the liquid flow path mainstream groove 61, and is 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 and perpendicular to the liquid flow path mainstream groove 61. Some liquid flow path communication grooves 65 are arranged to communicate adjacent liquid flow path mainstream grooves 61. Other liquid flow path communication grooves 65 are arranged to communicate the vapor flow path section 50 (first vapor passage 51 or second vapor passage 52) and the liquid flow path mainstream groove 61. That is, 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 the edge. In this way, the first vapor passage 51 or the second vapor passage 52 of the vapor flow path section 50 and the liquid flow path mainstream groove 61 communicate with each other.

[0063] The liquid flow path communication groove 65 has a flow path cross-sectional area smaller than the first steam passage 51 or the second steam passage 52 of the steam flow path section 50 so that the working fluid 2b flows mainly by capillary action. The liquid flow path communication grooves 65 may be disposed 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 a wall surface (not shown) formed in a curved shape like 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 portions 64 (liquid flow path protrusions) arranged in the X direction. The liquid flow path convex portions 64 are provided in the liquid flow path portion 60, and protrude from the sheet main body 31 to abut against the upper sheet 20. Each liquid flow path convex portion 64 is formed in a rectangular shape such that the X direction is the longitudinal direction in a plan view. A liquid flow path mainstream groove 61 is interposed between adjacent liquid flow path convex portions 64 in the Y direction, and a liquid flow path communication groove 65 is interposed between adjacent liquid flow path convex portions 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 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 process 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 manner. More specifically, 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 arranged to be shifted from each other in the X direction. This shift 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 means 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 arrangement, 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. In 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. As a result, in 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 (for example, the upper side in FIG. 8), the liquid flow path communication groove 65 on the other side (for example, the lower side in FIG. 8) can be prevented from communicating with the liquid flow path mainstream groove 61. As a result, in the liquid flow path intersection 66, the wall surface 62 of the liquid flow path mainstream groove 61 is prevented from being cut out on both sides (upper and lower sides in FIG. 8), and one side of the wall surface 62 can be left. Therefore, even in the liquid flow path intersection 66, the working fluid in the liquid flow path mainstream groove 61 can be given a capillary action, and the driving force of the working fluid 2b toward the evaporation region SR can be suppressed from decreasing in the liquid flow path intersection 66.

[0069] Next, the frame body protrusions 70 provided on the frame body portion 32 will be described. The frame body portion 32 has a plurality of frame body protrusions 70 formed in a convex shape toward the inside of the steam flow path portion 50 when viewed from the Z direction (thickness direction of the wick sheet 30) (in a plan view). That is, the frame body portion 32 has a plurality of frame body protrusions 70 formed in a convex shape toward the inside of the steam flow path portion 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 portion 50 in a plan view. In the present embodiment, the frame body protrusion 70 has a rectangular shape in a plan view. Moreover, the frame body protrusions 70 are provided at different positions from each other on the inner ends 32a, 32b of the frame body portion 32 in a plan view. In this embodiment, the frame protrusions 70 are disposed at equal intervals around the entire circumference of the inner ends 32a, 32b of the frame portion 32 in a plan view.

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

[0072] As shown in Fig. 9, the first convex portions 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 convex portions 71 may be arranged at equal intervals in the X direction. Also, as shown in Fig. 10, the second convex portions 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 convex portions 72 may be arranged at equal intervals in the Y direction.

[0073] The frame body protrusion 70 (the first protrusion 71 and the second protrusion 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 later. 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 protrusion 70 has 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 shown by the dashed line in Fig. 11, the inner ends 32a, 32b of the frame portion 32 also have a lower curved surface 32d and an upper curved surface 32e. The wall surface 53a of the lower steam passage recess 53 described above also includes this lower curved surface 32d, and the wall surface 54a of the upper steam passage recess 54 described above also includes this upper curved surface 32e. The lower curved surface 70d of the frame protrusion 70 is formed to protrude from the lower curved surfaces 32d of the inner ends 32a, 32b toward the first steam passage 51. The upper curved surface 70e of the frame protrusion 70 is formed to protrude from the upper curved surfaces 32e of the inner ends 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 etching from the first main body surface 31a of the wick sheet 30 in an etching process described later. 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 (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 from 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 a portion where the lower curved surface 70d and the upper curved surface 70e join together. The protrusion 70c protrudes into the first steam passage 51. When viewed in a cross section along the Z direction, the frame convex portion 70 has a lower end 70a of the lower curved surface 70d provided on the opposite side to the protrusion 70c, and an upper end 70b of the upper curved surface 70e provided on the opposite side to the protrusion 70c. When viewed in a cross section along the Z direction, the lower end 70a is an intersection point between the lower curved surface 70d and the first main body surface 31a, and the upper end 70b is an intersection point between 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 (the right side in FIG. 11) and is positioned closer to the inside of the first steam passage 51 than the upper end 70b. It should be noted that the contour line of the frame convex portion 70 (first convex portion 71) depicted in FIG. 9 corresponds to the contour line of the protrusion portion 70c in a 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 convex portion 71 may be larger than the surface roughness (arithmetic mean height Ra defined in JIS B 0601-2001) of the inner ends 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 ends 32a, 32b may be, for example, 0.1 μm to 5 μm, and the height h2 of the first convex portion 71 may be, for example, 10 μm to 200 μm. Note that the height h2 of the first convex portion 71 is the dimension of the first convex portion 71 in the Y direction as shown in FIG. 11, and means the dimension at the position where the through portion 34 exists in the Z direction. Also, as shown in FIG. 9, the width w6 (dimension in the X direction) of the first convex portion 71 may be, for example, 100 μm to 1000 μm. The first convex portions 71 may have the same shape and dimensions as each other. 9, the interval p1 between one first protrusion 71 and another first protrusion 71 adjacent thereto 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 the interval p1.

[0079] 10, the height h3 (dimension in the X direction) of the second convex portion 72 may be equal to the height h2 of the first convex portion 71. As shown in FIG. 10, the width w7 (dimension in the Y direction) of the second convex portion 72 may be equal to the width w6 of the first convex portion 71. The second convex portions 72 may have the same shape and dimensions as each other. As shown in FIG. 10, the interval p2 between one second convex portion 72 and the adjacent second convex portion 72 may be equal to the interval p1 between the first convex portions 71. That is, the second convex portions 72 may be arranged side by side in the second direction Y at the same arrangement pitch as the arrangement pitch of the first convex portions 71. In this way, the first convex portions 71 and the second convex portions 72 may have the same shape and dimensions as each other and be arranged at equal intervals around the entire circumference of the inner ends 32a, 32b of the frame body portion 32 in a plan view. However, without being limited thereto, each of the first convex portions 71 and each of the second convex portions 72 may have different shapes and dimensions from each other. Furthermore, each of the first convex portions 71 and each of the second convex portions 72 may be arranged to have different intervals from each other.

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

[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 portion 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 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 passage portion 50 can be appropriately secured, and the wick sheet 30 can appropriately function 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 thick.

[0084] Next, a method for manufacturing the vapor chamber 1 of this embodiment having such a configuration will be described with reference to Figures 12 to 14. Note that Figures 12 to 14 show the same cross section as the cross section of Figure 3.

[0085] First, the process of producing 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 body protrusion 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 of 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 steam flow path portion 50 and the liquid flow path portion 60 as shown in FIG. 13. The frame body protrusion 70 is also formed by this etching. The etching solution may be, for example, an iron chloride-based etching solution such as an aqueous solution of ferric chloride, or a copper chloride-based etching solution such as an aqueous solution of copper chloride.

[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 the above, and the etching of the first material surface Ma and the second material surface Mb may be performed in separate steps. In addition, 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 the present embodiment is obtained.

[0092] After the manufacturing process of the wick sheet 30, a joining process is performed in which the lower sheet 10, the upper sheet 20, and the wick sheet 30 are joined together as shown in Fig. 14. The lower sheet 10 and the upper sheet 20 may be formed of a 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 superimposed 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 superimposed 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 by diffusion bonding. Diffusion bonding is a method in which the lower sheet 10 and the wick sheet 30 are bonded to each other, and the wick sheet 30 and the upper sheet 20 are bonded to each other, and then pressurized and heated in the stacking direction in a controlled atmosphere such as a vacuum or an inert gas, to bond them by utilizing the diffusion of atoms that occurs at the bonding surface. In diffusion bonding, the material of each sheet 10, 20, 30 is heated to a temperature close to the melting point, but is lower than the melting point, so that each sheet 10, 20, 30 can be prevented from melting and deforming. More specifically, the first main body surface 31a of the frame body 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. Further, 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 in which the injection flow path 37 is closed.

[0096] After the joining process, 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 defined by each liquid flow path main groove 61 and each liquid flow path connection groove 65 of the liquid flow path section 60.

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

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

[0099] Next, a method for operating the vapor chamber 1, that is, a method for 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). The working liquid 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 flow path recess 53, the wall surface 54a of the upper vapor flow path recess 54, the wall surface 62 of the liquid flow path main groove 61 of the liquid flow path section 60, and the wall surface of the liquid flow path connecting groove 65, due to its surface tension. The working liquid 2b may also adhere to a portion of the second lower sheet surface 10b of the lower sheet 10 exposed to the lower vapor flow path recess 53. The working liquid 2b may also adhere to a portion of the first upper sheet surface 20a of the upper sheet 20 exposed to the upper vapor flow path recess 54, the liquid flow path main groove 61, and the liquid flow path 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 steam 2a. Most of the generated working steam 2a diffuses in the lower steam passage recess 53 and the upper steam passage recess 54 that form the sealed space 3 (see the solid arrows in FIG. 6). The working steam 2a in each of the steam passage recesses 53 and 54 leaves the evaporation region SR, and most of the working steam 2a is transported to the condensation region CR (the right part in FIG. 6) where the temperature is relatively low. In the condensation region CR, the working steam 2a is cooled by dissipating heat mainly to the lower sheet 10. The heat received by the lower sheet 10 from the working steam 2a is transferred to the outside air via the housing member Ha (see FIG. 3).

[0102] The working steam 2a radiates heat to the lower sheet 10 in the condensation region CR, and condenses in the evaporation region SR, losing the absorbed latent heat, to generate the working fluid 2b. The generated working fluid 2b adheres to the wall surfaces 53a, 54a of the vapor flow 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. Here, since the working fluid 2b continues to evaporate in the evaporation region SR, the working fluid 2b in the region of 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 the capillary action of each liquid flow path mainstream groove 61 (see the dashed arrow in FIG. 6). As a result, the working fluid 2b adhered 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 groove 65, and enters the liquid flow path mainstream groove 61. In this manner, the working fluid 2b is filled into each liquid flow path mainstream groove 61 and each liquid flow path connection groove 65. Therefore, the filled working fluid 2b obtains a propulsive 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 between the adjacent liquid flow path mainstream grooves 61, preventing the occurrence of 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 smoothly transported toward the evaporation region SR.

[0104] The working fluid 2b that has reached the evaporation region SR is evaporated by receiving heat from the device D again. The working vapor 2a that has evaporated from the working fluid 2b passes through the liquid flow path communication 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 a large flow path cross-sectional area, and diffuses in 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, to transport and release the heat of the device D. As a result, the device D is cooled.

[0105] Incidentally, the working fluid 2b generated by condensing the working steam 2a fills and remains in the liquid flow path mainstream groove 61 and the liquid flow path connecting groove 65 of the liquid flow path section 60. However, in general, a part of the working fluid 2b may not fill these grooves and 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, a part of the working fluid 2b may adhere to the inner end portions 32a, 32b of the frame section 32.

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

[0107] When the electronic device E equipped with the vapor chamber 1 is placed in a temperature environment lower than the freezing points of the working fluids 2a and 2b, the working fluid 2b attached 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, so that the first vapor passage 51 of the vapor passage section 50 is prevented from being blocked by the frozen working fluid 2b. Therefore, the flow of the working vapor 2a in the first vapor passage 51 can be prevented from being hindered by the freezing of the working fluid 2b, and the performance degradation of the vapor chamber 1 can be prevented.

[0108] Thus, according to this embodiment, the frame body 32 has a plurality of frame body protrusions 70 formed in a convex shape toward the inside of the vapor flow path 50 in a plan view. This can increase the contact area between the working fluid 2b and the frame body 32. This allows the working fluid 2b to spread in the frame body 32. Therefore, the working fluid 2b can be spread and dispersed in the inner ends 32a, 32b of the frame body 32, and can be prevented from remaining unevenly in a specific part. This can prevent the frozen working fluid 2b from blocking the vapor flow path 50 even if the electronic device E equipped with the vapor chamber 1 is placed in a temperature environment lower than the freezing point of the working fluids 2a, 2b and the working fluid 2b attached to the inner ends 32a, 32b of the frame body 32 freezes. As a result, it is possible to prevent the performance degradation of the vapor chamber 1.

[0109] According to this embodiment, the frame protrusions 70 include first protrusions 71 provided at a pair of inner ends 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., in the direction in which the working steam 2a flows. This makes it possible to prevent the frozen working fluid 2b from blocking the steam passage extending in the direction in which the working steam 2a flows in the steam flow path portion 50. In addition, 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 attached to the side of the condensation region CR to spread and disperse in the evaporation region SR. This makes it possible to prevent the working fluid 2b from freezing biased toward the side of the condensation region CR, and to prevent the frozen working fluid 2b from blocking the steam flow path portion 50. In this way, the performance degradation of the vapor chamber 1 can be effectively suppressed.

[0110] Furthermore, according to this embodiment, the multiple frame protrusions 70 include second protrusions 72 provided on a pair of inner ends 32b extending in the Y direction. This allows the working fluid 2b to be wetted and spread out and dispersed in the Y direction as well. This further prevents the vapor flow path portion 50 from being blocked by the 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. Since the frame protrusion 70 has a plurality of curved surfaces in this manner, the contact area between the working fluid 2b and the frame portion 32 can be further increased, and the working fluid 2b can be further wetted and spread in the frame portion 32. This makes it possible to further prevent the vapor flow path portion 50 from being blocked by the 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 further inward in the first vapor passage 51 than the lower end 70a, and is positioned further inward in the first vapor passage 51 than the upper end 70b. Such a 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 allows the number of etching processes to be reduced, and the manufacturing efficiency of the vapor chamber 1 to be improved.

[0113] According to this embodiment, the working fluids 2a and 2b having freeze-expansion are sealed in the vapor chamber 1. When the working fluids 2a and 2b having freeze-expansion freeze in the vapor flow path 50, the force caused by the expansion is received by the lower sheet 10 and the upper sheet 20, and the vapor chamber 1 is likely to be deformed. In contrast, according to this embodiment, the working fluid 2b can be spread and dispersed by wetting at the inner ends 32a and 32b of the frame 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. Therefore, the deformation of the vapor chamber 1 can be prevented.

[0114] (First Modification) In the above-described embodiment, an example in which the frame body protrusion 70 has a rectangular shape in a plan view has been described (see FIG. 9 and FIG. 10). However, the present invention is not limited to this, and the frame body protrusion 70 may have any shape as long as it is formed in a convex shape toward the steam flow path 50. For example, as shown in FIG. 15, the frame body protrusion 70 may have a triangular shape in a plan view. Also, for example, the frame body protrusion 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 protrusion 70 has a semicircular shape. In such a case, each dimension of the frame body protrusion 70 may be approximately the same as each dimension of the frame body protrusion 70 in the above-described embodiment. In addition, the arrangement pitch of the frame body protrusion 70 may also be approximately the same as the arrangement pitch of the frame body protrusion 70 in the above-described embodiment.

[0115] In the first modified example, the frame protrusion 70 can increase the contact area between the working fluid 2b and the frame portion 32, and the working fluid 2b can be made to wet and spread over 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 portion 70a and more inward than the upper end portion 70b in the first steam passage 51 (see FIG. 11). However, this is not limited to the above, and the lower end portion 70a or the upper end portion 70b may be positioned more inward in the first steam passage 51 than the protrusion portion 70c.

[0117] For example, as shown in FIG. 17, the protrusion 70c may protrude closer to the first steam passage 51 than the lower end 70a, and the upper end 70b may be located closer to the first steam passage 51 than the protrusion 70c. In this case, the frame protrusion 70 may be formed by etching only the first main body surface 31a of the wick sheet 30. For example, the frame protrusion 70 may be formed by performing two etching steps from the first main body surface 31a of the wick sheet 30. That is, in the first etching step, the resist film on the first main body surface 31a is patterned to have a shape corresponding to the lower steam passage recess 53, and the first material surface Ma of the metal material sheet M is etched through the opening of 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, the resist film is patterned to have a shape corresponding to the upper steam flow path recess 54, and 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 portion 50 is smallest is not the position of the through-portion 34 but the position where the upper end 70b exists in the Z direction. In this case, the contour line of the frame body protrusion 70 depicted in Figures 9 and 10 corresponds to the contour line of the upper end 70b in plan view.

[0118] For example, as shown in FIG. 18, the protrusion 70c may be positioned inside the first steam passage 51 relative to the upper end 70b, and the lower end 70a may be positioned inside the first steam passage 51 relative to the protrusion 70c. In this case, the frame body protrusion 70 may be formed by etching only from the second main body surface 31b of the wick sheet 30. For example, the frame body 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 flow path portion 50 is smallest is not the position of the through portion 34, but the position where the lower end 70a exists in the Z direction. In this case, the contour line of the frame body protrusion 70 depicted in FIG. 9 and FIG. 10 corresponds to the contour line of the lower end 70a in a plan view.

[0119] In addition, when the frame body convex portion 70 having the shape as 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 convex portion 70 may also be formed to have a similar shape.

[0120] In the second modified example, the frame protrusion 70 can increase the contact area between the working fluid 2b and the frame 32, and the working fluid 2b can be spread over the frame 32. Furthermore, according to the second modified example, the amount of protrusion of the protrusion 70c toward the inside of the first vapor passage 51 can be reduced. This allows the width of the first vapor passage 51 at the protrusion 70c to be increased, and the space of the first vapor passage 51 to be increased. Therefore, even if the working fluid 2b freezes, the vapor passage 50 can be further prevented from being blocked by the frozen working fluid 2b, and the performance degradation of the vapor chamber 1 can be further prevented.

[0121] The plurality of frame body protrusions 70 may include a frame body protrusion 70 as shown in Fig. 17 and a frame body protrusion 70 as shown in Fig. 18. Here, the frame body protrusion 70 as shown in Fig. 17 is referred to as an upper end side protrusion 74 (second end side protrusion), and the frame body protrusion 70 as shown in Fig. 18 is referred to as a lower end side protrusion 73 (first end side protrusion) and described. In this case, in the lower end side protrusion 73, as shown in Fig. 18, the protrusion 70c is positioned more inwardly of the first steam passage 51 than the upper end 70b, and the lower end 70a is positioned more inwardly of the first steam passage 51 than the protrusion 70c. In the upper end side convex portion 74, as shown in FIG. 17, the protrusion portion 70c is positioned more inwardly in the first steam passage 51 than the lower end portion 70a, and the upper end portion 70b is positioned more inwardly in the first steam passage 51 than the protrusion portion 70c. In addition, in a plan view, such lower end side convex portion 73 and upper end side convex portion 74 may be provided alternately. For example, as shown in FIG. 9, in each inner end portion 32a extending in the X direction, the lower end side convex portion 73 and the upper end side convex portion 74 may be arranged alternately in the X direction in a plan view. That is, the multiple first convex portions 71 may include the lower end side convex portion 73 and the upper end side convex portion 74 arranged alternately in the X direction. In addition, as shown in FIG. 10, in each inner end portion 32b extending in the Y direction, the lower end side convex portion 73 and the upper end side convex portion 74 may be arranged alternately in the Y direction in a plan view. That is, the multiple second convex portions 72 may include lower end side convex portions 73 and upper end side convex portions 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 body protrusions 70 are provided on each of a pair of inner ends 32a extending in the X direction and a pair of inner ends 32b extending in the Y direction (see FIG. 6). However, this is not limited to this, and the frame body protrusions 70 may be provided on one or more of the inner ends 32a, 32b of the frame body portion 32.

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

[0125] In the third modified example, the frame protrusion 70 can increase the contact area between the working fluid 2b and the frame portion 32, and the working fluid 2b can be made to wet and spread over 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 protrusion 70 is disposed over the entire circumference of the inner ends 32a, 32b of the frame body portion 32 in a plan view (see FIG. 6). However, this is not limited to this, and the frame body protrusion 70 may be disposed only in a partial region of the inner ends 32a, 32b of the frame body portion 32. Furthermore, the frame body protrusion 70 may not be disposed in the other regions.

[0127] For example, as shown in Fig. 19, the frame protrusion 70 may be provided in the condensation region CR. That is, in the case where 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 part 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 part 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 generated in the condensation region CR and evaporated in the evaporation region SR. Therefore, the working fluid 2b is more likely to adhere to the inner ends 32a, 32b of the frame portion 32, particularly on the condensation region CR side than the evaporation region SR. By providing the frame protrusion 70 on the condensation region CR side than the evaporation region SR as in the fourth modified example, the working fluid 2b adhering to the condensation region CR side can be wetted and spread to the evaporation region SR side. Therefore, it is possible to prevent the working fluid 2b from freezing biased toward the condensation region CR side, and it is possible to prevent the frozen working fluid 2b from blocking the vapor flow path portion 50. As a result, it is possible to effectively prevent the performance degradation of the vapor chamber 1. In addition, by restricting the provision of the frame protrusion 70 on the evaporation region SR side, it is possible to smooth the flow of the working vapor 2a on the evaporation region SR side. In other words, it is possible to smoothly transport the working vapor 2a from the evaporation region SR to the condensation region CR. Therefore, it is possible to prevent the performance degradation of the vapor chamber 1. In addition, by restricting the provision of the frame protrusion 70, it is possible to facilitate the manufacture of the vapor chamber 1. 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-mentioned embodiment and each modification, and the components can be modified and embodied in the implementation stage without departing from the gist of the invention. In addition, various inventions can be formed by appropriate combinations of the multiple components disclosed in the above-mentioned embodiment and each modification. Some components may be deleted from all the components shown in the above-mentioned embodiment and each modification. [Explanation of symbols]

[0130] 1 Vapor Chamber 2a Working steam 2b Hydraulic fluid 10 Lower sheet 20 Upper seat 30 Wick Sheet 32 Frame body part 33 Land Department 50 Steam flow passage 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 protrusion 72 Second protrusion 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

[Claim 1] A wick sheet for a vapor chamber, which is interposed between a first sheet and a second sheet of the vapor chamber in which a working fluid is sealed, A frame portion, A land portion provided within the frame portion; a steam flow passage portion through which the working fluid vapor passes, the steam flow passage portion being provided between the frame portion and the land portion; 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 when viewed in a plane.

Images