Vapor chamber and electronic device

Abstract

To improve heat transport efficiency.SOLUTION: A vapor chamber according to the present invention is filled with working fluid. The vapor chamber comprises a first sheet, a second sheet stacked on the first sheet, a third sheet interposed between the first sheet and the second sheet, a vapor flow passage part through which vapor of the working fluid is passed, and a liquid flow passage part through which the working fluid in liquid form is passed. The vapor flow passage part is provided on a surface of the second sheet on the side of the third sheet without being provided in the first sheet. The liquid flow passage part is provided between the first sheet and the third sheet. The third sheet is provided with a plurality of through holes penetrating the third sheet, and causing the vapor flow passage part and the liquid flow passage part to communicate with each other.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to 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 close to the device (evaporation region) and evaporates into vapor (working vapor). The working vapor diffuses away from the evaporation region in the vapor flow path, cools, and condenses into liquid. The vapor chamber is provided with a liquid flow path portion with a capillary structure (wick). The condensed working fluid (working liquid) enters the liquid flow path portion from the vapor flow path portion and flows through the liquid flow path toward the evaporation region. The working liquid then receives heat again in the evaporation region 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 improving heat dissipation efficiency. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-143960 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the capillary action of the liquid flow path is insufficient, the transport amount of the working liquid may decrease, and the heat transport efficiency may decrease.

[0006] The present invention has been made in consideration of the above points, and an object of the present invention is to provide a vapor chamber and an electronic device that can improve heat transport efficiency. [Means for solving the problem]

[0007] The present invention provides A vapor chamber containing a working fluid, The first sheet and a second sheet laminated on the first sheet; a third sheet interposed between the first sheet and the second sheet; a vapor flow path portion through which the vapor of the working fluid passes; a liquid flow path portion through which the liquid working fluid passes, the steam flow path portion is not provided on the first sheet, but is provided on a surface of the second sheet on the side of the third sheet, the liquid flow path portion is provided between the first sheet and the third sheet, a vapor chamber, in which the third sheet is provided with a plurality of through holes that penetrate the third sheet and communicate the vapor flow path portion with the liquid flow path portion; to provide.

[0008] In the vapor chamber described above, The liquid flow path portion is provided on a surface of the first sheet on the side of the third sheet. This may be done.

[0009] In addition, in the vapor chamber described above, the liquid flow path portion is provided on a surface of the third sheet on the side of the first sheet; This may be done.

[0010] In addition, in the vapor chamber described above, The aperture ratio of the through holes in the third sheet is 20% or more and 60% or less. This may be done.

[0011] The present invention also provides A vapor chamber containing a working fluid, The first sheet and a second sheet laminated on the first sheet; a third sheet interposed between the first sheet and the second sheet; a recessed space that is not provided in the first sheet but is provided on a surface of the second sheet on the side of the third sheet; a groove portion provided on a surface of the first sheet facing the third sheet or a surface of the third sheet facing the first sheet, The groove portion has a groove extending in a first direction, When viewed in a cross section perpendicular to the first direction, a width dimension of the recessed space is larger than a width dimension of the groove, a vapor chamber, wherein the third sheet is provided with a plurality of through holes that penetrate the third sheet and communicate with the recessed space and the groove portion; to provide.

[0012] 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]

[0013] According to the present invention, it is possible to improve the heat transport efficiency. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic perspective view illustrating an electronic device according to a first embodiment. [Figure 2]FIG. 2 is a top view showing the vapor chamber according to the first 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 intermediate sheet of FIG. [Figure 7] FIG. 7 is an enlarged cross-sectional view of a portion of FIG. [Figure 8] FIG. 8 is a cross-sectional view taken along line BB in FIG. [Figure 9] FIG. 9 is a partially enlarged top view of the liquid flow path portion shown in FIG. [Figure 10] FIG. 10 is a partially enlarged cross-sectional view of the liquid flow path portion shown in FIG. [Figure 11] FIG. 11 is a cross-sectional view showing a vapor chamber according to the second embodiment, and corresponds to FIG. [Figure 12] FIG. 12 is a partially enlarged cross-sectional view of FIG. 11, and corresponds to FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] 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.

[0016] 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 depicted 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.

[0017] (First embodiment) A vapor chamber and an electronic device according to a first embodiment of the present invention will be described with reference to Figures 1 to 10. Vapor chamber 1 according to this embodiment is a device mounted in electronic device E to cool device D, which is a heat generating body housed in electronic device E. Examples of device D include central processing units (CPUs), light-emitting diodes (LEDs), power semiconductors, and other heat-generating electronic devices (cooled devices) used in mobile devices such as handheld devices and tablet devices.

[0018] 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.

[0019] 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.

[0020] 2 and 3, the vapor chamber 1 includes a lower sheet 10 (first sheet), an upper sheet 20 (second sheet), and an intermediate sheet 30 (third sheet) 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 intermediate sheet 30, and the upper sheet 20 are laminated in this order.

[0021] 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. 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 intermediate 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.

[0022] 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.

[0023] The evaporation region SR is the region that overlaps with the device D in a planar view and is the region 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 in the center of the vapor chamber 1 in the X direction. Heat from the device D is transferred to the evaporation region SR, and this heat causes the liquid working fluid (referred to as working fluid 2b as appropriate) 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 surrounding area of ​​that region. Therefore, the evaporation region SR includes the region that overlaps with the device D and the surrounding area in a planar view. Here, the planar view refers to the state of the vapor chamber 1 as viewed from a direction perpendicular to the surface that receives heat from the device D (the first lower sheet surface 11a of the lower sheet 10, described later) and the surface that releases the received heat (the second upper sheet surface 21b of the upper sheet 20, described later). For example, as shown in FIG. 2, this corresponds to the state of the vapor chamber 1 as viewed from above or below.

[0024] 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 one side (left side in FIG. 2) and the other side (right side in FIG. 2) of the vapor chamber 1 in the X direction. In the condensation region CR, heat from the working vapor 2a is released to the upper sheet 20, and the working vapor 2a is cooled and condensed in the condensation region CR.

[0025] 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 lower sheet 10, and the sheet that releases the received heat will be referred to as the upper sheet 20. 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.

[0026] As shown in Fig. 3, the lower sheet 10 includes a lower sheet main body 11 and a liquid flow path section 60 (groove section) provided in the lower sheet main body 11. The lower sheet main body 11 has a first lower sheet surface 11a provided on the side opposite the intermediate sheet 30, and a second lower sheet surface 11b provided on the side opposite the first lower sheet surface 11a (i.e., the intermediate sheet 30 side). The device D described above is attached to this first lower sheet surface 11a. The liquid flow path section 60, which will be described later, is provided on the second lower sheet surface 11b. As shown in Fig. 4, alignment holes 15 may be provided in the four corners of the lower sheet 10.

[0027] As shown in Fig. 3, the upper sheet 20 includes an upper sheet main body 21 and a steam flow path portion 50 (recessed space) provided in the upper sheet main body 21. The upper sheet main body 21 has a first upper sheet surface 21a provided on the side of the intermediate sheet 30 and a second upper sheet surface 21b provided on the opposite side to the first upper sheet surface 21a. A housing member Ha that forms part of a housing H of a mobile terminal or the like is attached to this second upper sheet surface 21b. The second upper sheet surface 21b may be entirely covered by the housing member Ha. In addition, the steam flow path portion 50 is provided in the first upper sheet surface 21a.

[0028] 5, the upper sheet main body 21 has a frame portion 22 and a plurality of steam flow path protrusions 23 provided inside the frame portion 22. The frame portion 22 and the steam flow path protrusions 23 are not etched in the etching step described below, and the material of the upper sheet 20 remains.

[0029] In this embodiment, the frame portion 22 is formed in a rectangular frame shape in a plan view. A steam flow path portion 50, which is a flow path through which the working steam 2a passes, is defined inside the frame portion 22. In other words, the working steam 2a flows around the steam flow path protrusion 23 inside the frame portion 22.

[0030] The vapor flow path protrusion 23 is provided in the vapor flow path section 50 and is configured to protrude downward (toward the lower side in FIG. 3) from the ceiling surface 50a of the vapor flow path section 50. As shown in FIG. 3, the vapor flow path protrusion 23 has a protruding surface 23a located on the same plane as the first upper sheet surface 21a. This protruding surface 23a abuts against a second intermediate sheet surface 31b of the intermediate sheet 30, which will be described later. This improves the mechanical strength of the vapor chamber 1.

[0031] In this embodiment, as shown in Fig. 5, the steam flow path protrusions 23 are arranged in a staggered pattern in a plan view. This allows the working steam 2a to flow around the steam flow path protrusions 23, thereby preventing the flow of the working steam 2a from being obstructed. In this embodiment, the steam flow path protrusions 23 are formed in a circular shape in a plan view. This also prevents the flow of the working steam 2a from being obstructed. Note that the planar shape of the steam flow path protrusions 23 is not limited to a circular shape as long as it prevents the flow of the working steam 2a from being obstructed.

[0032] As shown in Fig. 3, the width w1 of the protruding surface 23a of each steam flow path protrusion 23 (the diameter of the protruding surface 23a in a plan view) may be, for example, 30 µm to 500 µm. Also, as shown in Fig. 3, the gap w2 between each steam flow path protrusion 23 may be, for example, 500 µm to 3000 µm. Here, the gap w2 between each steam flow path protrusion 23 is the dimension between adjacent steam flow path protrusions 23, and refers to the dimension on the first upper sheet surface 21 a.

[0033] The vapor flow path section 50 is primarily a flow path through which the working vapor 2a passes. As shown in FIG. 3, the vapor flow path section 50 is not provided on the lower sheet 10, but is provided on the first upper sheet surface 21a, which is the surface of the upper sheet 20 on the side of the intermediate sheet 30. The vapor flow path section 50 constitutes part of the sealed space 3 described above. As shown in FIG. 3, the vapor flow path section 50 is primarily defined by the ceiling surface 50a of the vapor flow path section 50, the frame body section 22 and the vapor flow path protrusion 23 described above, and the second intermediate sheet surface 31b of the intermediate sheet 30 described below. The vapor flow path section 50 may extend across the entire width of the vapor chamber 1, excluding the frame body section 22, in the Y direction perpendicular to the X direction.

[0034] The steam flow passage portion 50 has a relatively large flow passage cross-sectional area so that the working steam 2a can pass through. In the cross section shown in FIG. 3 (cross section perpendicular to the X direction), the vapor channel section 50 has a larger channel cross-sectional area than a liquid channel mainstream groove 61 of the liquid channel section 60, which will be described later. As shown in FIG. 3, the width w8 (width dimension) of the vapor channel section 50 is larger than the width w5 (width dimension) of the liquid channel mainstream groove 61, which will be described later. As shown in FIGS. 3 and 7, the gap w2 between the vapor channel protrusions 23 in the vapor channel section 50 is also larger than the width w5 of the liquid channel mainstream groove 61, which will be described later. As shown in FIGS. 3 and 7, the height h1 of the vapor channel section 50 is larger than the depth h2 of the liquid channel mainstream groove 61, which will be described later. The width w8 of the vapor channel section 50 may be, for example, 30 mm to 80 mm. Here, the width w8 of the vapor channel section 50 corresponds to the dimension of the entire width of the vapor chamber 1 in the Y direction, excluding the bonding surface with the second intermediate sheet surface 31b of the frame section 22. That is, the width w8 of the steam flow path section 50 is the dimension between a pair of inner ends of the frame body section 22 in the Y direction, and means the dimension at the first upper sheet surface 21a. The height h1 of the steam flow path section 50 may be, for example, 80 μm to 500 μm. Here, the height h1 of the steam flow path section 50 means the dimension between the ceiling surface 50a of the steam flow path section 50 and the protruding surface 23a of the steam flow path protrusion 23 in the Z direction.

[0035] The steam flow path portion 50 is formed by etching from the first upper sheet surface 21a of the upper sheet 20 in an etching step described below. As a result, the steam flow path portion 50 has a wall surface 51 formed in a curved shape, as shown in Fig. 3. This wall surface 51 defines the steam flow path portion 50 and is curved in a shape that bulges toward the second upper sheet surface 21b.

[0036] As shown in FIG. 5, the upper sheet 20 may have alignment holes 25 at its four corners.

[0037] As shown in Fig. 3, the intermediate sheet 30 includes an intermediate sheet main body 31 and a plurality of through holes 70 provided in the intermediate sheet main body 31. The intermediate sheet main body 31 has a first intermediate sheet surface 31a and a second intermediate sheet surface 31b provided on the opposite side to the first intermediate sheet surface 31a. The intermediate sheet 30 may be formed to be generally flat, or may have a uniform thickness overall. The first intermediate sheet surface 31a is disposed on the side of the lower sheet 10, and the second intermediate sheet surface 31b is disposed on the side of the upper sheet 20.

[0038] The through holes 70 extend from the first intermediate sheet surface 31a to the second intermediate sheet surface 31b and penetrate the intermediate sheet main body 31. In this embodiment, as shown in FIG. 6, the through holes 70 are arranged in a lattice pattern in a plan view. Also, in this embodiment, as shown in FIG. 6, the through holes 70 are formed in a rectangular (square) shape in a plan view. Note that the arrangement of the through holes 70 is not limited to a lattice pattern and may be any arrangement. Furthermore, the planar shape of the through holes 70 is not limited to a rectangular shape and may be any shape, for example, a circular shape.

[0039] 7, the through-hole 70 is formed by a lower recess 71 provided in the first intermediate sheet surface 31a and an upper recess 72 provided in the second intermediate sheet surface 31b. The through-hole 70 is formed so that the lower recess 71 and the upper recess 72 are in communication with each other and extend from the first intermediate sheet surface 31a to the second intermediate sheet surface 31b.

[0040] The lower recess 71 is formed in a concave shape on the first intermediate sheet surface 31a by etching from the first intermediate sheet surface 31a of the intermediate sheet 30 in an etching process described below. As a result, the lower recess 71 has a curved wall surface 71a, as shown in Fig. 7. This wall surface 71a defines the lower recess 71 and is curved in a shape that bulges toward the second intermediate sheet surface 31b. Such a lower recess 71 constitutes a part (lower half) of the through hole 70.

[0041] The upper recess 72 is formed in a concave shape on the second intermediate sheet surface 31b by etching the second intermediate sheet surface 31b of the intermediate sheet 30 in an etching process described below. As a result, the upper recess 72 has a curved wall surface 72a, as shown in Fig. 7. This wall surface 72a defines the upper recess 72 and is curved in a shape that bulges toward the first intermediate sheet surface 31a. Such an upper recess 72 constitutes a part (upper half) of the through hole 70.

[0042] As shown in FIG. 7 , a wall surface 71a of the lower recess 71 and a wall surface 72a of the upper recess 72 are connected to form a through-hole 73. The wall surfaces 71a and 72a are each curved toward the through-hole 73. This allows the lower recess 71 and the upper recess 72 to communicate with each other. In this embodiment, the planar shape of the through-hole 73 is rectangular (square). The through-hole 73 may be defined by a ridge line formed by the joining of the wall surface 71a of the lower recess 71 and the wall surface 72a of the upper recess 72, which juts out inward. The planar area of ​​the through-hole 70 is minimized at the through-hole 73.

[0043] The position of the through-hole 73 in the Z direction may be the middle position between the first intermediate sheet surface 31 a and the second intermediate sheet surface 31 b, or may be shifted downward or upward from the middle position. The position of the through-hole 73 is arbitrary as long as the lower recess 71 and the upper recess 72 are connected to each other.

[0044] In addition, in this embodiment, the cross-sectional shape of the through-hole 70 is defined by a ridgeline formed to protrude inward, but this is not limited to this. For example, the cross-sectional shape of the through-hole 70 may be trapezoidal, rectangular, or barrel-shaped.

[0045] The through holes 70 configured in this manner are open into the vapor channel section 50, as shown in FIG. 8. As a result, the vapor channel section 50 and the liquid channel section 60 are in communication with each other via the plurality of through holes 70. In the illustrated example, at least one through hole 70 is disposed between adjacent vapor channel protrusions 23. As shown in FIG. 7, the width w3 of the through hole 70 (the dimension of one side of the square-shaped through hole 70) is smaller than the gap w2 between the vapor channel protrusions 23, and may be, for example, 50 μm to 500 μm. Here, the width w3 of the through hole 70 refers to the dimension of the through hole 70 in the X or Y direction, and refers to the dimension at the position where the through portion 73 is located in the Z direction. Also, as shown in FIG. 7, the gap w4 between each through hole 70 may be, for example, 50 μm to 500 μm. Here, the gap w4 between each through hole 70 refers to the dimension between adjacent through holes 70, and refers to the dimension at the position where the through portion 73 is located in the Z direction. The aperture ratio of the through holes 70 in the intermediate sheet 30 may be 20% or more and 60% or less. Here, the aperture ratio of the through holes 70 means the ratio of the total aperture area of ​​the through holes 70 to the area of ​​the second intermediate sheet surface 31b of the intermediate sheet 30 (including the portion where the through holes 70 are provided).

[0046] In addition, in Figures 6 and 8, the through holes 70 and the like are shown enlarged to make the drawings clearer, and the number and arrangement of the through holes 70 in Figures 6 and 8 are different from those in Figures 3 and 7, etc.

[0047] As shown in FIG. 6, alignment holes 35 may be provided at the four corners of the intermediate sheet body 31 of the intermediate sheet 30.

[0048] The second lower sheet surface 11b of the lower sheet body 11 and the first intermediate sheet surface 31a of the intermediate sheet body 31 may be permanently bonded to each other by diffusion bonding. Similarly, the first upper sheet surface 21a of the upper sheet body 21 and the second intermediate sheet surface 31b of the intermediate sheet body 31 may be permanently bonded to each other by diffusion bonding. The lower sheet 10, the upper sheet 20, and the intermediate 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 intermediate sheet 30 are bonded to a degree that allows the lower sheet 10 and the intermediate sheet 30 to be bonded to a degree that allows the sealed space 3 to be kept sealed when the vapor chamber 1 is in operation, and that allows the upper sheet 20 and the intermediate sheet 30 to be bonded to a degree that allows the lower sheet 10 and the intermediate sheet 30 to be bonded to a degree that allows the sealed space 3 to be kept sealed when the vapor chamber 1 is in operation.

[0049] As shown in FIG. 2, the vapor chamber 1 may further include an injection portion 4 for injecting the working fluid 2b into the sealed space 3 at one edge in the X direction.

[0050] More specifically, the injection section 4 may be configured to have a lower injection protrusion 16 (see FIG. 4) constituting the lower sheet 10, an upper injection protrusion 26 (see FIG. 5) constituting the upper sheet 20, and an intermediate injection protrusion 36 (see FIG. 6) constituting the intermediate sheet 30. Of these, an injection flow path 27 is formed in the upper injection protrusion 26. This injection flow path 27 is formed in a concave shape on the first upper sheet surface 21a (upper injection protrusion 26). The injection flow path 27 is also connected to the steam flow path section 50, and the working fluid 2b is injected into the sealed space 3 through the injection flow path 27. The injection flow path 27 may be formed in the lower injection protrusion 16 and connected to the liquid flow path section 60, or may be formed in the intermediate injection protrusion 36 and connected to the through-hole 70. The upper and lower surfaces of the middle injection protrusion 36 are flat, and the upper surface of the lower injection protrusion 16 and the lower surface of the upper injection protrusion 26 are also flat. The planar shapes of the injection protrusions 16, 26, and 36 may be the same.

[0051] In this embodiment, the injection part 4 is shown as being provided on one of a pair of edges in the X direction of the vapor chamber 1, but this is not limited to this and the injection part 4 can be provided at any position.

[0052] Next, the liquid flow path section 60 will be described. The liquid flow path section 60 is a flow path through which the hydraulic fluid 2b mainly passes. The liquid flow path section 60 is provided between the lower sheet 10 and the intermediate sheet 30. In this embodiment, as shown in Figs. 3, 4 and 7, the liquid flow path section 60 is provided on the second lower sheet surface 11b of the lower sheet 10.

[0053] The liquid flow path section 60 constitutes a part of the sealed space 3 described above. The liquid flow path section 60 is in communication with the vapor flow path section 50 via a plurality of through holes 70. The liquid flow path section 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 section 60 is formed on the second lower sheet surface 11b of the lower sheet 10. The liquid flow path section 60 may be formed over the entire inside of the frame body section 22 in a plan view. The liquid flow path section 60 does not have to be provided in the region of the upper sheet 20 that overlaps with the frame body section 22 in a plan view.

[0054] In this embodiment, the liquid flow path section 60 is composed of a plurality of grooves provided in the second lower sheet surface 11b. As shown in Fig. 9, 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.

[0055] As shown in Fig. 9, each liquid flow path mainstream groove 61 is formed to extend in the X direction. The liquid flow path mainstream groove 61 has a flow path cross-sectional area smaller than that of the vapor flow path section 50 so that the working liquid 2b flows 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. The liquid flow path mainstream grooves 61 may be arranged at equal intervals in the Y direction.

[0056] The liquid flow path main grooves 61 are formed by etching from the second lower sheet surface 11b of the lower sheet 10 in an etching step described below. As a result, the liquid flow path main grooves 61 have curved wall surfaces 62, as shown in Fig. 10. These wall surfaces 62 define the liquid flow path main grooves 61 and are curved in a shape that bulges toward the first lower sheet surface 11a.

[0057] 7 and 9, the width w5 (dimension in the Y direction) of the liquid flow path mainstream groove 61 may be, for example, 5 μm to 150 μm. Here, the width w5 of the liquid flow path mainstream groove 61 refers to the dimension on the second lower sheet surface 11b. Also, as shown in FIG. 7, the depth h2 (dimension in the Z direction) of the liquid flow path mainstream groove 61 may be, for example, 3 μm to 150 μm.

[0058] 9, 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 is formed perpendicular to the liquid flow path main grooves 61. The liquid flow path communication grooves 65 are arranged so as to connect adjacent liquid flow path main grooves 61 to each other.

[0059] 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) formed in a curved shape similar to that of the liquid flow path mainstream groove 61. As shown in Fig. 9, the width w6 (dimension in the X direction) of the liquid flow path connecting groove 65 may be equal to the width w5 of the liquid flow path mainstream groove 61, or may be greater or smaller than the width w5. The depth of the liquid flow path connecting groove 65 may be equal to the depth h2 of the liquid flow path mainstream groove 61, or may be greater or smaller than the depth h2.

[0060] As shown in FIG. 9 , 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 bottom surface of the liquid flow path section 60, and abut against the first intermediate sheet surface 31a of the intermediate sheet 30. 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 connects 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.

[0061] The liquid flow path convex portions 64 are portions that are not etched in the etching step described below, and remain as the material of the intermediate sheet 30. In this embodiment, as shown in Fig. 9, the planar shape of the liquid flow path convex portions 64 (the shape at the position of the second lower sheet surface 11b) is rectangular.

[0062] 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 w7 (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 w7 of the liquid flow path convex portions 64 refers to the dimension on the second lower sheet surface 11b. 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.

[0063] 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. 9 ) 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. 9 ). 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. 9 ) 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.

[0064] The liquid flow path section 60 configured in this manner is provided on the second lower sheet surface 11b, which is the surface of the lower sheet 10 facing the intermediate sheet 30. As a result, some of the multiple liquid flow path main grooves 61 of the liquid flow path section 60 are covered by the first intermediate sheet surface 31a of the intermediate sheet 30. In this case, as shown in FIG. 10 , the wall surfaces 62 of the liquid flow path main grooves 61 and the first intermediate sheet surface 31a form two right-angled or acute-angled corners 67, and capillary action can be enhanced at these two corners 67. Similarly, some of the multiple liquid flow path communication grooves 65 of the liquid flow path section 60 are covered by the first intermediate sheet surface 31a of the intermediate sheet 30. Capillary action can also be enhanced in the liquid flow path communication grooves 65. As a result, the capillary action of the liquid flow path section 60 is enhanced, and the working fluid 2b can be smoothly transported toward the evaporation region SR by capillary action.

[0065] The materials constituting the lower sheet 10, upper sheet 20, and intermediate sheet 30 are not particularly limited as long as they have good thermal conductivity. However, the lower sheet 10, upper sheet 20, and intermediate 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 or titanium, or other metal alloy materials such as stainless steel can also be used for these sheets 10, 20, and 30 as long as the desired heat dissipation efficiency can be achieved and corrosion can be prevented.

[0066] 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 mechanical strength of the vapor chamber 1 can be increased, and by ensuring the vapor flow path section 50 and the liquid flow path section 60, the vapor chamber 1 can function. 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 large.

[0067] The thickness t2 of the lower sheet 10 may be, for example, 25 μm to 200 μm. By making the thickness t2 of the lower sheet 10 25 μm or more, the mechanical strength of the vapor chamber 1 can be increased, and by ensuring the liquid flow path portion 60, it is possible to function as the vapor chamber 1. On the other hand, by making the thickness t2 of the lower sheet 10 200 μm or less, it is possible to prevent the thickness t1 of the vapor chamber 1 from becoming too large.

[0068] The thickness t3 of the upper sheet 20 may be, for example, 100 μm to 1000 μm. By making the thickness t3 of the upper sheet 20 100 μm or more, the mechanical strength of the vapor chamber 1 can be increased, and by ensuring the vapor flow path portion 50, it is possible to operate as the vapor chamber 1. On the other hand, by making the thickness t3 1000 μm or less, it is possible to prevent the thickness t1 of the vapor chamber 1 from becoming too thick.

[0069] The thickness t4 of the intermediate sheet 30 may be, for example, 18 μm to 100 μm. By making the thickness t4 of the intermediate sheet 30 18 μm or more, the handleability of the intermediate sheet 30 can be improved. On the other hand, by making the thickness t4 100 μm or less, the thickness t1 of the vapor chamber 1 can be prevented from increasing, and an increase in resistance in the vapor channel section 50 can be suppressed. Furthermore, the thickness t4 of the intermediate sheet 30 may be smaller than the width w3 of the through-hole 70. This can further suppress an increase in resistance in the vapor channel section 50.

[0070] Next, a method for manufacturing the vapor chamber 1 of this embodiment having such a configuration will be described.

[0071] First, the manufacturing process of each of the sheets 10, 20, and 30 will be described.

[0072] First, in a preparation step, a flat metal material sheet that includes a first material surface and a second material surface and forms the lower sheet 10 is prepared.

[0073] After the preparation step, in the etching step, the metal material sheet is etched from the first material surface to form the liquid flow path portion 60.

[0074] More specifically, a patterned resist film is formed on a first material surface of a metal material sheet by photolithography. Subsequently, the first material surface of the metal material sheet is etched through the openings in the patterned resist film. As a result, the first material surface of the metal material sheet is etched in a pattern, forming the liquid flow path portion 60. Note that, for example, an iron chloride-based etching solution such as a ferric chloride aqueous solution, or a copper chloride-based etching solution such as a copper chloride aqueous solution can be used as the etching solution.

[0075] In this way, the lower sheet 10 according to this embodiment is obtained.

[0076] Similarly, in the preparation step, a flat metal material sheet is prepared to form the upper sheet 20. Then, in the etching step, the metal material sheet is etched from the first material surface to form the liquid flow path portion 60. In this manner, the upper sheet 20 according to this embodiment is obtained.

[0077] Similarly, in the preparation step, a flat metal material sheet that forms the intermediate sheet 30 is prepared. Then, in the etching step, the metal material sheet is etched from the first material surface and the second material surface to form the through-holes 70. More specifically, the metal material sheet is etched from the first material surface to form a lower recess 71 on the first material surface. Furthermore, the metal material sheet is etched from the second material surface to form an upper recess 72 on the second material surface. Here, the first material surface and the second material surface of the metal material sheet may be etched simultaneously. However, this is not limited thereto, and the etching of the first material surface and the second material surface may be performed in separate steps. In this manner, the intermediate sheet 30 according to this embodiment is obtained.

[0078] After the steps of producing the sheets 10, 20, and 30, the lower sheet 10, the upper sheet 20, and the middle sheet 30 are joined together in a joining step.

[0079] More specifically, first, the lower sheet 10, the intermediate sheet 30, and the upper sheet 20 are laminated in this order. In this case, the first intermediate sheet surface 31a of the intermediate sheet 30 is superimposed on the second lower sheet surface 11b of the lower sheet 10, and the first upper sheet surface 21a of the upper sheet 20 is superimposed on the second intermediate sheet surface 31b of the intermediate sheet 30. At this time, the alignment holes 15 of the lower sheet 10, 35 of the intermediate sheet 30, and 25 of the upper sheet 20 are used to align the sheets 10, 20, and 30.

[0080] Next, the lower sheet 10, the middle sheet 30, and the upper sheet 20 are temporarily joined together. For example, these sheets 10, 20, and 30 may be temporarily joined together by spot resistance welding, or by laser welding.

[0081] Next, the lower sheet 10, the intermediate 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 intermediate sheet 30, and also the intermediate sheet 30 and the upper sheet 20, and then applying pressure and heat in the stacking direction in a controlled atmosphere, such as a vacuum or an inert gas, to bond them together by utilizing atomic diffusion that occurs 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 intermediate sheet surface 31a of the intermediate sheet 30 is diffusion bonded to the second lower sheet surface 11b of the lower sheet 10. The second intermediate sheet surface 31b of the intermediate sheet 30 is diffusion bonded to the first upper sheet surface 21a of the upper sheet 20. In this way, the sheets 10, 20, 30 are diffusion bonded together, forming 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 16 of the lower sheet 10 is diffusion bonded to the middle injection protrusion 36 of the middle sheet 30. Furthermore, the middle injection protrusion 36 is diffusion bonded to the upper injection protrusion 26 of the upper sheet 20, forming an injection flow path 27.

[0082] 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 formed by each liquid flow path main groove 61 and each liquid flow path connecting groove 65 of the liquid flow path section 60.

[0083] Thereafter, the above-mentioned injection flow path 27 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 27. 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 27 can be sealed by caulking injection portion 4 (pressing to cause plastic deformation) or brazing.

[0084] In this manner, the vapor chamber 1 according to this embodiment is obtained.

[0085] Next, the method of operating the vapor chamber 1, that is, the method of cooling the device D, will be described.

[0086] 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 an apparatus to be cooled, is attached to the first upper sheet surface 21a of the lower sheet 10 (or the vapor chamber 1 is attached to the device D). The working fluid 2b in the sealed space 3 adheres due to its surface tension to the wall surfaces of the sealed space 3, i.e., the wall surface 51 of the vapor flow path section 50, the wall surface 71a of the lower recess 71 and the wall surface 72a of the upper recess 72 of the through-hole 70, and the wall surface 62 of the liquid flow path main groove 61 and the wall surface of the liquid flow path connecting groove 65 of the liquid flow path section 60.

[0087] In this state, when the device D generates heat, the working fluid 2b present in the evaporation region SR (see Figures 2, 4, and 5) 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 vapor flow path section 50 that constitutes the sealed space 3 (see the solid arrows in Figure 5). The working vapor 2a in the vapor flow path section 50 leaves the evaporation region SR, and most of the working vapor 2a is transported to the condensation region CR (the left and right portions in Figure 6), which has a relatively low temperature. In the condensation region CR, the working vapor 2a is cooled by radiating heat mainly to the upper sheet 20. The heat received by the upper sheet 20 from the working vapor 2a is transferred to the outside air via the housing member Ha (see Figure 3).

[0088] The working vapor 2a dissipates heat to the upper sheet 20 in the condensation region CR, thereby losing the latent heat it absorbed in the evaporation region SR and condensing, generating working fluid 2b. The generated working fluid 2b adheres to the wall surface 51 of the vapor channel section 50. Here, since the working fluid 2b continues to evaporate in the evaporation region SR, the working fluid 2b in the region of the liquid channel 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 channel mainstream groove 61 (see the dashed arrows in FIG. 4). As a result, the working fluid 2b adhering to the wall surface 51 of the vapor channel section 50 passes through the through-holes 70 and enters the liquid channel mainstream grooves 61 and the liquid channel connecting grooves 65 of the liquid channel section 60. In this way, the working fluid 2b is filled in each liquid channel mainstream groove 61 and each liquid channel connecting groove 65. Therefore, the filled working fluid 2b receives a driving force toward the evaporation region SR due to the capillary action of each liquid flow path main groove 61, and is transported smoothly toward the evaporation region SR.

[0089] 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.

[0090] Furthermore, in the liquid flow path section 60, some of the multiple liquid flow path mainstream grooves 61 are covered by the first intermediate sheet surface 31a of the intermediate sheet 30. As a result, two corners 67 are formed by the wall surfaces 62 of the liquid flow path mainstream grooves 61 and the first intermediate sheet surface 31a, and capillary action is enhanced at these two corners 67. The capillary action is also enhanced in the liquid flow path connection grooves 65. As a result, the capillary action in the liquid flow path section 60 is enhanced, and the working fluid 2b is smoothly transported toward the evaporation region SR.

[0091] The working fluid 2b that has reached 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 moves from the liquid flow path section 60 through the through-holes 70 to the vapor flow path section 50, and diffuses within the vapor flow path section 50. In this way, the working fluids 2a and 2b circulate within the sealed space 3 while repeatedly undergoing phase changes, i.e., evaporation and condensation, transporting and releasing heat from the device D. As a result, the device D is cooled.

[0092] As described above, according to this embodiment, the liquid flow path section 60 is provided between the lower sheet 10 and the intermediate sheet 30. In particular, according to this embodiment, the liquid flow path section 60 is provided on the surface of the lower sheet 10 facing the intermediate sheet 30 (second lower sheet surface 11b). This allows the intermediate sheet 30 (first intermediate sheet surface 31a) to cover part of the liquid flow path section 60 (liquid flow path main grooves 61 and liquid flow path connecting grooves 65). This enhances the capillary action of the liquid flow path section 60, allowing the working fluid 2b to be smoothly transported toward the evaporation region SR. As a result, the transport amount of the working fluid 2b can be increased, and the heat transport efficiency can be improved. Furthermore, more liquid flow path sections 60 (liquid flow path main grooves 61 and liquid flow path connecting grooves 65) can be provided on the surface of the lower sheet 10 facing the intermediate sheet 30 (second lower sheet surface 11b). This further increases the transport amount of the working fluid 2b, and further improves the heat transport efficiency.

[0093] Furthermore, according to this embodiment, the vapor flow path section 50 is not provided on the lower sheet 10, but is provided on the surface of the upper sheet 20 on the side of the intermediate sheet 30 (first upper sheet surface 21a). The vapor flow path section 50 is configured to have a relatively large flow path cross-sectional area to allow the working vapor 2a to pass through, so by not providing the vapor flow path section 50 on the lower sheet 10, the thickness t2 of the lower sheet 10 can be made thin. By giving each sheet a different function in this way (in this embodiment, the lower sheet 10 is given a liquid transport function and the upper sheet 20 is given a vapor transport function), the thickness t1 of the vapor chamber 1 can be made thin.

[0094] Furthermore, according to this embodiment, the vapor flow path portion 50 is not provided on the lower sheet 10, so that more liquid flow path portions 60 (liquid flow path main grooves 61 and liquid flow path connecting grooves 65) can be provided on the surface (second lower sheet surface 11b) of the lower sheet 10 on the side of the intermediate sheet 30. This makes it possible to further improve the transport amount of the working fluid 2b and further improve the heat transport efficiency.

[0095] Furthermore, according to this embodiment, the aperture ratio of the through holes 70 in the intermediate sheet 30 is 20% or more and 60% or less. Having an aperture ratio of the through holes 70 of 20% or more allows the working steam 2a to move quickly from the liquid flow path section 60 to the steam flow path section 50, and allows the working fluid 2b to move quickly from the steam flow path section 50 to the liquid flow path section 60. On the other hand, having an aperture ratio of the through holes 70 of 60% or less allows a larger number of the liquid flow path sections 60 (liquid flow path main grooves 61 and liquid flow path connecting grooves 65) to be covered by the intermediate sheet 30 (first intermediate sheet surface 31a). Having an aperture ratio of the through holes 70 of 20% or more and 60% or less in this way allows the heat transport efficiency to be improved more effectively.

[0096] (Second embodiment) Next, a vapor chamber and an electronic device according to a second embodiment of the present invention will be described with reference to FIGS.

[0097] The second embodiment shown in Figures 11 and 12 differs mainly in that the liquid flow path section is provided on the surface of the intermediate sheet facing the lower sheet, and other configurations are substantially the same as those of the first embodiment shown in Figures 1 to 10. In Figures 11 and 12, the same parts as those in the first embodiment shown in Figures 1 to 10 are designated by the same reference numerals and detailed description thereof will be omitted.

[0098] As shown in FIGS. 11 and 12 , in this embodiment, the liquid flow path section 60 is not provided on the lower sheet 10, and the lower sheet 10 is formed flat. In this embodiment, the liquid flow path section 60 is provided on the first intermediate sheet surface 31a, which is the surface of the intermediate sheet 30 facing the lower sheet 10. In this embodiment, the liquid flow path section 60 is composed of a plurality of grooves provided on the first intermediate sheet surface 31a. As in the first embodiment described above, the liquid flow path section 60 has a plurality of liquid flow path main grooves 61 and a plurality of liquid flow path communication grooves 65 that connect adjacent liquid flow path main grooves 61. The liquid flow path section 60 also communicates with the through-holes 70 via the liquid flow path communication grooves 65. This allows the generated working fluid 2b to enter the liquid flow path section 60 from the vapor flow path section 50 through the through-holes 70, and the generated working steam 2a to move from the liquid flow path section 60 through the through-holes 70 to the vapor flow path section 50. The dimensions of the liquid flow path main groove 61 and the liquid flow path connecting groove 65 may be the same as those in the first embodiment described above, or may be different.

[0099] In the example shown in FIGS. 11 and 12 , the shape of the through hole 70 is also different from that of the first embodiment described above, with the upper recess 72 being larger than the lower recess 71. The position of the through hole 73, formed by the connection of the wall surface 71 a of the lower recess 71 and the wall surface 72 a of the upper recess 72, is located below the midpoint between the first intermediate seat surface 31 a and the second intermediate seat surface 31 b (on the side of the first intermediate seat surface 31 a). The number and arrangement of the through holes 70 are also different from those of the first embodiment described above, with one through hole 70 being located between adjacent steam flow path protrusions 23. Thus, the number of through holes 70 is fewer than in the first embodiment. This allows more liquid flow path sections 60 (liquid flow path main grooves 61 and liquid flow path connecting grooves 65) to be provided on the first intermediate seat surface 31 a. The shape, number, and arrangement of the through holes 70 are not limited to those described above and may be arbitrary.

[0100] In this embodiment, the number of through holes 70 is smaller than in the first embodiment, and therefore, as shown in FIG. 12, the width w3' of the through holes 70 may be larger than the width w3 of the through holes 70 in the first embodiment. The width w3' of the through holes 70 may be, for example, 50 μm to 300 μm. Furthermore, as shown in FIG. 11, the gap w4' between the through holes 70 may be larger than the gap w4 between the through holes 70 in the first embodiment. The gap w4' between the through holes 70 may be, for example, 100 μm to 4000 μm. The aperture ratio of the through holes 70 in the intermediate sheet 30 may be the same as in the first embodiment described above.

[0101] The liquid flow path portion 60 according to this embodiment can be formed by etching the intermediate sheet 30 from the first intermediate sheet surface 31a during the etching process of the intermediate sheet 30. The through-holes 70 according to this embodiment can be formed by etching the intermediate sheet 30 from both the first intermediate sheet surface 31a and the second intermediate sheet surface 31b during the etching process. The first intermediate sheet surface 31a and the second intermediate sheet surface 31b of the intermediate sheet 30 may be simultaneously etched to simultaneously form the liquid flow path portion 60, the lower recess 71, and the upper recess 72. However, this is not limited to this, and the etching of the first intermediate sheet surface 31a and the second intermediate sheet surface 31b may be performed in separate processes. In this case, the liquid flow path portion 60 and the lower recess 71 may be simultaneously formed during the etching of the first intermediate sheet surface 31a, or the liquid flow path portion 60 and the lower recess 71 may be formed in separate etching processes. In this manner, the intermediate sheet 30 according to this embodiment is obtained.

[0102] As described above, according to this embodiment, the liquid flow path section 60 is provided on the surface (first intermediate sheet surface 31a) of the intermediate sheet 30 facing the lower sheet 10. This allows the liquid flow path section 60 (liquid flow path main grooves 61 and liquid flow path connecting grooves 65) to be covered by the lower sheet 10 (second lower sheet surface 11b). This enhances the capillary action of the liquid flow path section 60, allowing the working fluid 2b to be smoothly transported toward the evaporation region SR. As a result, the transport amount of the working fluid 2b can be increased, and heat transport efficiency can be improved. Furthermore, because the lower sheet 10 (second lower sheet surface 11b) is formed flat, the liquid flow path section 60 can be more reliably covered by the lower sheet 10. This allows the capillary action of the liquid flow path section 60 to be more reliably enhanced.

[0103] Furthermore, according to this embodiment, even if misalignment occurs between the lower sheet 10 and the intermediate sheet 30 during the bonding process during manufacturing of the vapor chamber 1, the liquid flow path section 60 can be more reliably covered by the lower sheet 10. This prevents fluctuations in the magnitude of capillary action in the liquid flow path section 60 due to misalignment between the lower sheet 10 and the intermediate sheet 30. This prevents the magnitude of capillary action in the liquid flow path section 60 from significantly deviating from the design value due to manufacturing errors in the vapor chamber 1, thereby facilitating the design of the liquid flow path section 60. Furthermore, the accuracy of alignment between the lower sheet 10 and the intermediate sheet 30 during the bonding process during manufacturing of the vapor chamber 1 can be reduced, thereby facilitating the manufacturing of the vapor chamber 1. Furthermore, this prevents a decrease in the capillary action in the liquid flow path section 60 due to misalignment between the lower sheet 10 and the intermediate sheet 30, thereby preventing a decrease in heat transport efficiency.

[0104] Furthermore, according to this embodiment, it is possible to eliminate the need to provide the liquid flow path section 60 in the lower sheet 10. This allows the thickness t2 of the lower sheet 10 to be further reduced, and therefore the thickness t1 of the vapor chamber 1 to be further reduced.

[0105] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be created by appropriately combining the multiple components disclosed in the above-described embodiments. Some components may be omitted from all the components shown in the above-described embodiments. [Explanation of symbols]

[0106] 1 Vapor chamber 2a Working steam 2b Hydraulic fluid 10 Lower seat 20 Upper seat 30 Middle seat 50 Steam flow path section 60 Liquid flow path section 70 through holes D Device E-electronic equipment H Housing

Claims

1. A vapor chamber containing a working fluid, The first sheet, a second sheet laminated on the first sheet; a third sheet interposed between the first sheet and the second sheet; a vapor flow path portion through which the vapor of the working fluid passes; a liquid flow path portion through which the liquid working fluid passes, the steam flow path portion is provided on a surface of the second sheet on the side of the third sheet, the liquid flow path portion is provided between the first sheet and the third sheet, the third sheet is provided with a plurality of through holes that penetrate the third sheet and communicate with the liquid flow path portion; a protrusion protruding toward the third sheet is provided in the steam flow path portion, the protruding portion abuts against a surface of the third sheet on the side of the second sheet, A vapor chamber, wherein one of the plurality of through holes is positioned so as to overlap the vapor flow path portion in a planar view, and another of the plurality of through holes is positioned so as to overlap the protrusion portion in a planar view.

2. A vapor chamber containing a working fluid, The first sheet, a second sheet laminated on the first sheet; a third sheet interposed between the first sheet and the second sheet; a vapor flow path portion through which the vapor of the working fluid passes; a liquid flow path portion through which the liquid working fluid passes, the steam flow path portion is provided on a surface of the second sheet on the side of the third sheet, the liquid flow path portion is provided between the first sheet and the third sheet, the third sheet is provided with a plurality of through holes that penetrate the third sheet and communicate with the liquid flow path portion; a protrusion protruding toward the third sheet is provided in the steam flow path portion, the protruding portion abuts against a surface of the third sheet on the side of the second sheet, A vapor chamber, wherein one of the plurality of through holes is directly connected to the vapor flow path portion, and another of the plurality of through holes is not directly connected to the vapor flow path portion.

3. A vapor chamber containing a working fluid, The first sheet, a second sheet laminated on the first sheet; a third sheet interposed between the first sheet and the second sheet; a recessed space provided on a surface of the second seat on the side of the third seat; a groove portion provided on a surface of the first sheet facing the third sheet or a surface of the third sheet facing the first sheet, The third sheet is provided with a plurality of through holes that pass through the third sheet and communicate with the groove portion, a protrusion protruding toward the third sheet is provided in the recessed space, the protruding portion abuts against a surface of the third sheet on the side of the second sheet, A vapor chamber, wherein one of the plurality of through holes is positioned so as to overlap with the recessed space in a planar view, and another of the plurality of through holes is positioned so as to overlap with the protrusion in a planar view.

4. A vapor chamber containing a working fluid, The first sheet, a second sheet laminated on the first sheet; a third sheet interposed between the first sheet and the second sheet; a recessed space provided on a surface of the second seat on the side of the third seat; a groove portion provided on a surface of the first sheet facing the third sheet or a surface of the third sheet facing the first sheet, The third sheet is provided with a plurality of through holes that pass through the third sheet and communicate with the groove portion, a protrusion protruding toward the third sheet is provided in the recessed space, the protruding portion abuts against a surface of the third sheet on the side of the second sheet, A vapor chamber, wherein one of the plurality of through holes is directly connected to the recessed space, and another of the plurality of through holes is not directly connected to the recessed space.

5. the protruding portion has a protruding surface that abuts against a surface of the third sheet on the side of the second sheet, The vapor chamber according to claim 1 , wherein the width of the protruding surface is greater than the width of the through hole.

6. The vapor chamber according to claim 1 , wherein a plurality of the protrusions are provided.

7. The vapor chamber according to claim 6 , wherein the protrusions are arranged in a staggered pattern in a plan view.

8. The vapor chamber according to claim 6 or 7, wherein the gap between adjacent protrusions is 500 μm to 3000 μm.

9. The vapor chamber according to claim 6 , wherein the width of the through hole is smaller than the gap between adjacent protrusions.

10. The vapor chamber according to claim 6 , wherein at least one of the through holes is disposed between adjacent ones of the protrusions in a plan view.

11. The vapor chamber according to claim 1 , wherein the protrusion is formed in a circular shape in a plan view.

12. the protruding portion has a protruding surface that abuts against a surface of the third sheet on the side of the second sheet, The vapor chamber according to any one of claims 1 to 11, wherein the width of the protruding surface is between 30 μm and 500 μm.

13. The vapor chamber according to claim 1 , wherein the protrusion tapers toward the third sheet in a cross-sectional view.

14. The vapor chamber according to any one of claims 1 to 13, wherein the height of the protrusion is between 80 μm and 500 μm.

15. An electronic device comprising the vapor chamber according to any one of claims 1 to 14.

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