Sheets for vapor chamber, vapor chamber, and electronic device

Abstract

To provide a vapor chamber and metal sheets for the vapor chamber that make it possible to perform work for deaeration in the vapor chamber and work for injection of working liquid into the vapor chamber in a short time at the time of manufacturing of the vapor chamber.SOLUTION: A vapor chamber comprises a first metal sheet, and a second metal sheet provided on the first metal sheet. In at least one of the first metal sheet and the second metal sheet, a plurality of vapor flow passage concave parts through which vapor of working liquid is passed is formed. In at least one of the first metal sheet and the second metal sheet, a liquid flow passage part through which the working liquid in a liquid state is passed is formed. In at least one of the first metal sheet and the second metal sheet, an injection flow passage concave part into which the working liquid in the liquid state is injected is formed. The width of the injection flow passage concave part is wider than the width of a lower side vapor passage of the vapor flow passage concave parts.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] Devices that generate heat, such as a central processing unit (CPU) used in mobile terminals such as mobile phones and tablet terminals, are cooled by heat dissipation members such as heat pipes (see, for example, Patent Document 1). In recent years, in order to make mobile terminals such as mobile phones thinner, thinner heat dissipation members have also been demanded, and the development of vapor chambers that can be made thinner than heat pipes has been promoted. A working fluid is enclosed in the vapor chamber, and the working fluid absorbs the heat of the device and releases it to the outside, thereby cooling the device.

[0003] More specifically, the working fluid in the vapor chamber receives heat from the device at a portion (evaporation section) close to the device and evaporates into vapor. Then, the vapor moves to a position away from the evaporation section, is cooled, and condenses into a liquid state. A capillary structure (wick) as a liquid flow path section is provided in the vapor chamber, and the liquefied working fluid passes through this liquid flow path section and is transported to the evaporation section, where it receives heat again and evaporates. In this way, the working fluid refluxes in the vapor chamber while repeating phase changes, that is, evaporation and condensation, thereby transferring the heat of the device and improving the heat dissipation efficiency.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in a flat heat exchanger such as a vapor chamber, an injection path for injecting a working fluid is provided in a metal sheet after degassing. However, if the width of the injection path is made narrower than the width of the vapor passage or the groove of the wick, as in the sheet-type heat pipe described in Patent Document 1, for example, degassing in the vapor chamber and injecting the working fluid into the vapor chamber take time, resulting in a problem of reduced workability.

[0006] The present invention has been made in consideration of such points, and an object thereof is to provide a vapor chamber, an electronic device, and a metal sheet for a vapor chamber capable of performing degassing work in the vapor chamber and injection work of a working fluid into the vapor chamber in a short time during the manufacture of the vapor chamber.

Means for Solving the Problems

[0007] The present invention is a vapor chamber in which a working fluid is enclosed, a first metal sheet, and a second metal sheet laminated on the first metal sheet, wherein at least one of the first metal sheet and the second metal sheet is formed with a vapor flow path recess including a plurality of vapor passages through which vapor of the working fluid passes, at least one of the first metal sheet and the second metal sheet is formed with a liquid flow path portion through which the liquid working fluid passes, at least one of the first metal sheet and the second metal sheet is formed with an injection flow path recess for injecting the liquid working fluid, and the width of the injection flow path recess is wider than the width of the vapor passage, and provides a vapor chamber. to provide.

[0008] In the vapor chamber described above, a plurality of struts may be provided protruding from the injection flow path recess. in this way.

[0009] Also, in the vapor chamber described above, a caulking region is formed in the injection flow path recess, and the caulking region has a plurality of protrusions. It may be like this.

[0010] Also, in the vapor chamber described above, the width of the injection flow path recess is 1.5 times or more the width of the vapor passage. It may be like this.

[0011] Also, in the vapor chamber described above, the depth of the injection flow path recess is deeper than the depth of the vapor passage. It may be like this.

[0012] Also, in the vapor chamber described above, the liquid flow path portion has a plurality of main flow grooves extending parallel to each other and communication grooves connecting the adjacent main flow grooves. It may be like this.

[0013] Also, in the vapor chamber described above, a convex portion is formed so as to be surrounded by the main flow groove and the communication groove, and the plurality of convex portions are arranged in a staggered pattern in plan view. It may be like this.

[0014] Also, in the vapor chamber described above, the second metal sheet is provided on the first metal sheet. It may be like this.

[0015] Also, in the vapor chamber described above, it further includes a third metal sheet interposed between the first metal sheet and the second metal sheet. One of the first metal sheet and the second metal sheet is formed with the vapor flow path recess, and the other is formed with the liquid flow path portion. The third metal sheet is provided with a communication part that communicates the vapor flow path recess and the liquid flow path part. This may be done.

[0016] Furthermore, the present invention is a vapor chamber filled with a working fluid, a first metal sheet, a second metal sheet laminated on the first metal sheet, a third metal sheet interposed between the first metal sheet and the second metal sheet, and includes the third metal sheet includes a first surface provided on the side of the first metal sheet and a second surface provided on the side of the second metal sheet, a vapor flow path part including a plurality of vapor passages through which the vapor of the working fluid passes is formed on at least one of the first surface and the second surface of the third metal sheet, a liquid flow path part through which the liquid working fluid passes is formed on at least one of the first surface and the second surface of the third metal sheet, an injection flow path part for injecting the liquid working fluid is formed on at least one of the first surface and the second surface of the third metal sheet, a vapor chamber in which the width of the injection flow path part is wider than the width of the vapor passage. is provided.

[0017] Furthermore, the present invention is a housing, a device housed in the housing, an electronic device including the vapor chamber thermally contacting the device described above. is provided.

[0018] Furthermore, the present invention is a metal sheet for a vapor chamber for a vapor chamber filled with a working fluid, a first surface, a second surface provided on the side opposite to the first surface, and includes A vapor flow path recess including a plurality of vapor paths through which vapor of the working fluid passes is formed in the first surface. An injection flow path recess for injecting the liquid working fluid is formed in the first surface, and the width of the injection flow path recess is wider than the width of the vapor path. A metal sheet for a vapor chamber. To provide.

Advantages of the Invention

[0019] According to the present invention, during the manufacture of the vapor chamber, the degassing operation in the vapor chamber and the operation of injecting the working fluid into the vapor chamber can be performed in a short time.

Brief Description of the Drawings

[0020]

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Embodiments for Carrying Out the Invention

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to this specification, for the convenience of illustration and easy understanding, the scale, the aspect ratio of the vertical and horizontal dimensions, etc. are appropriately changed and exaggerated from those of the actual object.

[0022] Also, with regard to terms used in this specification that specify shapes, geometric conditions, physical properties, and their degrees, such as terms like "parallel", "orthogonal", "identical", etc., as well as lengths, angles, and values of physical properties, they are not bound by a strict meaning and are to be interpreted to include a range that can be expected to have a similar function. Furthermore, in the drawings, for clarity, the shapes of a plurality of parts that can be expected to have a similar function are regularly described, but without being bound by a strict meaning, within the range where the said function can be expected, the shapes of these parts may be different from each other. Also, in the drawings, the boundary lines indicating the joint surfaces between members, etc. are shown as simple straight lines for convenience, but are not bound to be strict straight lines, and within the range where the desired joint performance can be expected, the shape of the said boundary line is arbitrary.

[0023] (First Embodiment) With reference to FIGS. 1 to 16, the vapor chamber, the electronic device, and the metal sheet for the vapor chamber in the first embodiment of the present invention will be described. The vapor chamber 1 in the present embodiment is a device mounted on the electronic device E in order to cool the device D as a heat generating body housed in the electronic device E. Examples of the device D include electronic devices (devices to be cooled) that generate heat, such as a central processing unit (CPU), a light emitting diode (LED), and a power semiconductor used in mobile terminals such as mobile phones and tablet terminals.

[0024] 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 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 is arranged to be in thermal contact with the device D. Thereby, the vapor chamber 1 can receive the heat generated by 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 through a working fluid 2 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.

[0025] Next, the vapor chamber 1 in the present embodiment will be described. The vapor chamber 1 has a sealed space 3 filled with a working fluid 2, and the working fluid 2 in the sealed space 3 repeats a phase change to effectively cool the device D of the above-described electronic device E.

[0026] The vapor chamber 1 is generally formed in a thin flat plate shape. The planar shape of the vapor chamber 1 is arbitrary, and it may be a rectangular shape as shown in FIG. 2. In this case, the vapor chamber 1 has four linear outer edges 1a, 1b forming the planar outer contour. Two of these outer edges 1a are formed along a first direction X described later, and the remaining two outer edges 1b are formed along a second direction Y described later. 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. The planar dimensions of the vapor chamber 1 are arbitrary. Also, the planar shape of the vapor chamber 1 is not limited to a rectangular shape, and can be any shape such as a circular shape, an elliptical shape, an L-shaped, a T-shaped, etc.

[0027] As shown in FIGS. 2 and 3, the vapor chamber 1 includes a lower metal sheet 10 (the first metal sheet or the second metal sheet, the metal sheet for the vapor chamber), and an upper metal sheet 20 (the second metal sheet or the first metal sheet, the metal sheet for the vapor chamber) laminated on the lower metal sheet 10. In the present embodiment, the upper metal sheet 20 is provided on the lower metal sheet 10. The lower metal sheet 10 has an upper surface 10a (the first surface) and a lower surface 10b (the second surface) provided on the side opposite to the upper surface 10a. The upper metal sheet 20 has a lower surface 20a (the surface on the side of the lower metal sheet 10) overlapped with the upper surface 10a (the surface on the side of the upper metal sheet 20) of the lower metal sheet 10, and an upper surface 20b provided on the side opposite to the lower surface 20a. A device D, which is an object to be cooled, is attached to the lower surface 10b of the lower metal sheet 10 (especially, the lower surface of the evaporation section 11 described later).

[0028] A sealed space 3 filled with the working fluid 2 is formed between the lower metal sheet 10 and the upper metal sheet 20. In the present embodiment, the sealed space 3 mainly has a vapor flow path section 80 (the lower vapor flow path recess 12 and the upper vapor flow path recess 21 described later) through which the vapor of the working fluid 2 passes, and a liquid flow path section 30 through which the liquid working fluid 2 mainly passes. Examples of the working fluid 2 include pure water, ethanol, methanol, acetone, and the like.

[0029] The lower metal sheet 10 and the upper metal sheet 20 are joined by diffusion bonding described later. In the forms shown in FIGS. 2 and 3, the portions of the lower metal sheet 10 and the upper metal sheet 20 excluding the injection section 4 described later are all formed in a rectangular shape in plan view, but it is not limited thereto. Here, the plan view is a state seen from a direction orthogonal to the surface (the lower surface 10b of the lower metal sheet 10) on which the vapor chamber 1 receives heat from the device D and the surface (the upper surface 20b of the upper metal sheet 20) that releases the received heat, and corresponds to, for example, a state of viewing the vapor chamber 1 from above (see FIG. 2) or from below.

[0030] In addition, when the vapor chamber 1 is installed inside the mobile terminal, depending on the orientation of the mobile terminal, the vertical relationship between the lower metal sheet 10 and the upper metal sheet 20 may be disrupted. However, in the present embodiment, for convenience, the metal sheet that receives heat from the device D is referred to as the lower metal sheet 10, and the metal sheet that releases the received heat is referred to as the upper metal sheet 20, and the description will be given in a state where the lower metal sheet 10 is disposed on the lower side and the upper metal sheet 20 is disposed on the upper side.

[0031] As shown in FIG. 2, the vapor chamber 1 further includes an injection portion 4 for injecting the working fluid 2 into the sealed space 3 at one of a pair of end portions in the first direction X. The injection portion 4 has a lower injection protrusion 16 that protrudes laterally from the end face of the lower metal sheet 10 (the face corresponding to the outer edge 1b in FIG. 2), and an upper injection protrusion 25 that protrudes laterally from the end face of the upper metal sheet 20 (the face corresponding to the outer edge 1b in FIG. 2). Among these, a lower injection flow path recess 17 (injection flow path recess) is formed on the upper surface of the lower injection protrusion 16 (the surface corresponding to the upper surface 10a of the lower metal sheet 10) (see FIG. 4). On the other hand, on the lower surface of the upper injection protrusion 25 (the surface corresponding to the lower surface 20a of the upper metal sheet 20), no recess is formed, and the upper injection protrusion 25 has the same thickness as the metal material sheet before processing (the metal material sheet M described later) (see FIG. 5). The inner end (the end on the sealed space 3 side) of the lower injection flow path recess 17 communicates with the lower vapor flow path recess 12, and the outer end (the end on the side opposite to the sealed space 3) of the lower injection flow path recess 17 opens outward. The lower injection flow path recess 17 and the upper injection protrusion 25 form an injection flow path for the working fluid 2 integrally when the lower metal sheet 10 and the upper metal sheet 20 are joined. Then, the working fluid 2 passes through the injection flow path and is injected into the sealed space 3. In the present embodiment, an example is shown in which the injection portion 4 is provided at one of a pair of end portions in the first direction X of the vapor chamber 1, but it is not limited thereto, and it can be provided at an arbitrary position. Also, two or more injection portions 4 may be provided.

[0032] Next, the configuration of the lower metal sheet 10 will be described. As shown in FIG. 4, the lower metal sheet 10 has an evaporation portion 11 where the working fluid 2 evaporates to generate vapor, and a lower vapor flow path recess 12 (first vapor flow path portion) provided on the upper surface 10a and formed in a rectangular shape in plan view. Among these, the lower vapor flow path recess 12 constitutes a part of the above-described sealed space 3 and is mainly configured such that the vapor generated in the evaporation portion 11 passes through it.

[0033] The evaporation portion 11 is disposed within the lower vapor flow path recess 12, and the vapor within the lower vapor flow path recess 12 diffuses in a direction away from the evaporation portion 11, and most of the vapor is transported toward the peripheral portion having a relatively low temperature. Note that the evaporation portion 11 is a portion where the working fluid 2 within the sealed space 3 evaporates by receiving heat from the device D attached to the lower surface 10b of the lower metal sheet 10. For this reason, the term "evaporation portion 11" is used as a concept that includes not only the portion overlapping the device D but also a portion where the working fluid 2 can evaporate even if it does not overlap the device D. Here, the evaporation portion 11 can be provided at any location on the lower metal sheet 10, but in FIGS. 2 and 4, an example where it is provided at the central portion of the lower metal sheet 10 is shown. In this case, the operation of the vapor chamber 1 can be stabilized regardless of the posture of the mobile terminal on which the vapor chamber 1 is installed.

[0034] In this embodiment, as shown in FIGS. 3 and 4, a plurality of lower channel wall portions 13 (first channel protruding portions) protruding upward (in a direction perpendicular to the bottom surface 12a) from the bottom surface 12a (described later) of the lower vapor flow path recess 12 are provided in the lower vapor flow path recess 12 of the lower metal sheet 10. In this case, the lower channel wall portions 13 protrude in a direction perpendicular to the bottom surface 12a, but are not limited thereto, and may protrude in a direction not perpendicular to the bottom surface 12a. In this embodiment, an example is shown in which the lower channel wall portions 13 extend in an elongated shape along the first direction X (longitudinal direction, left-right direction in FIG. 4) of the vapor chamber 1. The lower channel wall portion 13 includes an upper surface 13a (contact surface, protruding end surface) that contacts the lower surface 22a of the upper channel wall portion 22 described later. The upper surface 13a is a surface that is not etched by the etching process described later and is formed on the same plane as the upper surface 10a of the lower metal sheet 10. Further, the lower channel wall portions 13 are spaced apart at equal intervals and arranged parallel to each other.

[0035] As shown in FIGS. 3 and 4, the lower steam flow path recess 12 includes a plurality of lower steam passages 81 (first steam passages) partitioned by the lower flow path wall portions 13. The lower steam passages 81 extend in an elongated shape along the first direction X and are arranged parallel to each other. Both ends of each lower steam passage 81 communicate with a lower connecting steam passage 82 that extends in an elongated shape along the second direction Y, and each lower steam passage 81 communicates with the lower connecting steam passage 82. In this way, the steam of the working fluid 2 flows around each lower flow path wall portion 13 (the lower steam passage 81 and the lower connecting steam passage 82), and the steam is configured to be transported toward the peripheral edge of the lower steam flow path recess 12, suppressing the obstruction of the steam flow. In FIG. 3, the cross-sectional shape (cross-section in the second direction Y) of the lower steam passage 81 of the lower steam flow path recess 12 is rectangular. However, it is not limited to this, and the cross-sectional shape of the lower steam passage 81 may be, for example, curved, semi-circular, or V-shaped, as long as the steam of the working fluid 2 can be diffused. The same applies to the lower connecting steam passage 82. The width (dimension in the second direction Y) w7 of the lower steam passage 81 corresponds to the interval between the lower flow path wall portions 13 described later. The same applies to the width (dimension in the first direction X) of the lower connecting steam passage 82.

[0036] The lower flow path wall portion 13 is arranged so as to overlap with the corresponding upper flow path wall portion 22 (described later) of the upper metal sheet 20 in a plan view, aiming to improve the mechanical strength of the vapor chamber 1. The lower steam passage 81 is formed so as to overlap with the corresponding upper steam passage 83 (described later) in a plan view. Similarly, the lower connecting steam passage 82 is formed so as to overlap with the corresponding upper connecting steam passage 84 (described later) in a plan view.

[0037] The width w0 of the lower channel wall portion 13 is, for example, 0.05 mm to 30 mm, preferably 0.05 mm to 2.0 mm, and the width w7 of the lower steam passage 81 of the lower steam channel recess 12 (that is, the distance between adjacent lower channel wall portions 13) is 0.05 mm to 30 mm, preferably 0.05 mm to 2.0 mm. Here, the widths w0 and w7 are the dimensions of the lower channel wall portion 13 and the lower steam channel recess 12 in the second direction Y of the lower channel wall portion 13, and respectively mean the dimensions on the upper surface 10a of the lower metal sheet 10, and correspond to the vertical dimensions in FIG. 4, for example. Also, the height of the lower channel wall portion 13 (in other words, the maximum depth of the lower steam channel recess 12) h0 (see FIG. 3) is preferably at least 10 μm smaller than the thickness T1 of the lower metal sheet 10. If the remainder obtained by subtracting h0 from T1 is 10 μm or more, it is possible to prevent the lower steam channel recess 12 from being damaged due to insufficient strength. The thickness of the vapor chamber 1 may be 0.1 mm to 2.0 mm, and the thickness T1 of the lower metal sheet 10 and the thickness T2 of the upper metal sheet 20 may be equal. For example, when the thickness of the vapor chamber 1 is 0.5 mm and T1 and T2 are the same, h0 is preferably 200 μm.

[0038] As shown in FIGS. 3 and 4, a lower peripheral wall 14 is provided at the peripheral edge of the lower metal sheet 10. The lower peripheral wall 14 is formed so as to surround the sealed space 3, particularly the lower steam channel recess 12, and defines the sealed space 3. Further, lower alignment holes 15 for positioning the lower metal sheet 10 and the upper metal sheet 20 are provided at the four corners of the lower peripheral wall 14 in plan view.

[0039] The lower injection protrusion 16 of the injection portion 4 described above is used when degassing the sealed space 3 or injecting the liquid working fluid 2 into the sealed space 3 during the manufacture of the vapor chamber 1. The lower injection protrusion 16 is formed to protrude outward from the end surface of the lower metal sheet 10 in plan view. Note that the lower injection protrusion 16 is formed at a position deviated from the central portion in the width direction (second direction Y) of the lower metal sheet 10, but is not limited thereto, and may be formed at the central portion in the width direction (second direction Y) of the lower metal sheet 10.

[0040] On the upper surface of the lower injection protrusion 16, a lower injection flow path recess 17 extending along the longitudinal direction (first direction X) of the lower metal sheet 10 is formed. The lower injection flow path recess 17 is formed as a non-through recess formed by half-etching from the upper surface side of the lower injection protrusion 16. An opening 17a for degassing the inside of the sealed space 3 or injecting the liquid working fluid 2 into the sealed space 3 is formed at the outer end of the lower injection flow path recess 17 (the end opposite to the lower vapor flow path recess 12). This opening 17a communicates the lower injection flow path recess 17 with the outside of the vapor chamber 1 and is open outward (opposite to the lower vapor flow path recess 12).

[0041] On both sides in the width direction (second direction Y) of the lower injection flow path recess 17, bank portions 51 are respectively formed. These bank portions 51 constitute the wall portions on both sides of the lower injection flow path recess 17. The bank portions 51 are regions that are not etched, and their upper surfaces are formed on the same plane as the upper surface 10a of the lower metal sheet 10.

[0042] The length (distance in the first direction X) L1 of the lower injection protrusion 16 may be, for example, 5 mm to 30 mm, preferably 5 mm to 20 mm, and the width (distance in the second direction Y) w8 of the lower injection protrusion 16 may be, for example, 4 mm to 15 mm, preferably 4 mm to 10 mm. Also, the width w9 of the lower injection channel recess 17 is, for example, 1 mm to 10 mm, preferably 1 mm to 6 mm. Note that the width w9 means the dimension of the lower injection channel recess 17 in the second direction Y, and corresponds to, for example, the vertical dimension in FIG. 4. By setting L1 to 5 mm or more, workability is improved during evacuation of the sealed space 3, and by setting it to 30 mm or less, problems such as deformation are less likely to occur during operations such as evacuation. Also, by setting w8 to 4 mm or more, it is possible to obtain a sufficient width of the joint portion 51 while ensuring the width w9 of the lower injection channel recess 17, and by setting it to 15 mm or less, operations such as evacuation become easier. By setting w9 to 1 mm or more, the cross-sectional area of the injection channel becomes larger, and the degassing operation and the injection operation of the working fluid 2 can be performed efficiently and quickly. By setting it to 10 mm or less, leakage after caulking is less likely to occur.

[0043] The width w9 of the lower injection channel recess 17 may be wider than the width w7 of the lower vapor passage 81 described above. In this case, for example, the width w7 is 0.05 mm to 2.0 mm, and the width w9 is 1 mm to 10 mm. Also, it is preferable that the width w9 of the lower injection channel recess 17 is 1.5 times or more the width w7 of the lower vapor passage 81. More specifically, for example, when the width w7 is 0.05 mm, the width w9 may be 1 mm to 6 mm, preferably 1 mm to 3 mm. Also, for example, when the width w7 is 2 mm, the width w9 may be 3.5 mm to 10 mm, preferably 3.5 mm to 6 mm. Thus, by making the width w9 of the lower injection channel recess 17 wider than the width w7 of the lower vapor passage 81, degassing from the sealed space 3 and injection of the working fluid 2 into the sealed space 3 can be performed quickly.

[0044] Note that the width w9 of the lower injection channel recess 17 refers to the width at the widest part of the lower injection channel recess 17, for example, the maximum distance between both earthen parts 51. Similarly, the width w7 of the lower steam passage 81 refers to the width at the widest part of the lower steam channel recess 12.

[0045] Next, with reference to FIGS. 6 and 7, the configuration of the lower injection channel recess 17 will be further described. As shown in FIG. 6, in the lower injection channel recess 17, an inlet region 52, an intermediate region 53, and a caulking region 54 are formed along the longitudinal direction from the opening 17a toward the sealed space 3.

[0046] Among these, the inlet region 52 is a region into which the liquid working fluid 2 flows from the opening 17a. It is directly connected to the opening 17a and has a substantially flat bottom surface 17b on which no unevenness is formed.

[0047] The intermediate region 53 is located between the inlet region 52 and the caulking region 54. In this intermediate region 53, a plurality of support columns 55 project from the lower injection channel recess 17. Each support column 55 projects upward from the bottom surface 17b. Each support column 55 is a region that is not etched, and its upper surface is formed on the same plane as the upper surface 10a of the lower metal sheet 10. The lower surface 20a of the upper metal sheet 20 contacts the upper surface of each support column 55 (see FIG. 7). These plurality of support columns 55 play a role in improving the strength of the lower injection channel recess 17 and suppressing the deformation of the lower injection protrusion 16 and the blockage of the inside of the lower injection channel recess 17. By providing such a plurality of support columns 55, the internal space of the lower injection channel recess 17 can be secured, and the degassing of the sealed space 3 and the injection of the working fluid 2 into the sealed space 3 can be performed more reliably.

[0048] The plurality of support columns 55 are formed along each of the longitudinal direction (first direction X) and the width direction (second direction Y) of the lower injection flow path recess 17 (in this embodiment, a total of eight, four in the first direction X and two in the second direction Y). Each support column 55 has a rectangular shape in plan view, but is not limited thereto, and may have a circular shape, an elliptical shape, or a polygonal shape in plan view. Also, the shapes of the plurality of support columns 55 are the same as each other, but the shapes of the plurality of support columns 55 may be different from each other. The width w10 of each support column 55 may be, for example, 0.1 mm to 2 mm. Further, the interval p1 between the support columns 55 may be, for example, 0.1 mm to 2 mm, and the interval p2 between the support column 55 and the earthen part 51 may be, for example, 0.1 mm to 2 mm. By setting w10 to 0.1 mm or more, the strength as a support column is improved, and by setting it to 2 mm or less, the degassing operation and the injection operation of the working fluid 2 can be efficiently and quickly performed. By setting p1 and p2 to 0.1 mm or more, the degassing operation and the injection operation of the working fluid 2 can be efficiently and quickly performed, and by setting them to 2 mm or less, deformation is less likely to occur in the upper injection protrusion 25 during joining, and it is possible to suppress a decrease in the cross-sectional area of the injection flow path.

[0049] The caulking region 54 is a region that is closed and sealed by caulking (pressing and plastically deforming) after injecting the working fluid 2 into the sealed space 3. This caulking region 54 has a plurality of protrusions 56 protruding upward within the lower injection flow path recess 17. Each protrusion 56 is a region that is not etched, and its upper surface is formed on the same plane as the upper surface 10a of the lower metal sheet 10. The lower surface 20a of the upper metal sheet 20 contacts the upper surface of each protrusion 56 (see FIG. 7). The plurality of protrusions 56 are deformed by being crushed by caulking to close the lower injection flow path recess 17. By providing the plurality of protrusions 56 in the caulking region 54 in this way, the sealing of the sealed space 3 into which the working fluid 2 has been injected can be performed more reliably.

[0050] A plurality of protrusions 56 are formed in plural numbers in each of the longitudinal direction (first direction X) and the width direction (second direction Y) of the lower injection channel recess 17. Each protrusion 56 has a rectangular shape in plan view, but is not limited thereto, and may have a circular shape, an elliptical shape, or a polygonal shape in plan view. Further, the width w11 of each protrusion 56 may be, for example, 0.01 mm to 0.5 mm, and the interval p3 between the protrusions 56 may be, for example, 0.01 mm to 0.5 mm. Note that the width w11 of each protrusion 56 is smaller than the width of the width w10 of each support column 55, and the interval p3 between the protrusions 56 is narrower than the interval p1 between the support columns 55. Since the width w9 of the lower injection channel recess 17 is formed to be sufficiently wider than the width w7 of the lower vapor passage 81 as described above, it is possible to prevent the degassing operation in the sealed space 3 and the injection operation of the working fluid 2 into the sealed space 3 from being hindered by the presence of the plurality of protrusions 56 in the caulking region 54.

[0051] As shown in Fig. 7, the depth d1 of the lower injection channel recess 17 may be, for example, 40 μm to 300 μm. In this case, the depth d1 of the lower injection channel recess 17 may be deeper than the depth h0 of the lower vapor channel recess 12. In this case, for example, the depth h0 is 10 μm to 200 μm, and the depth d1 is 40 μm to 300 μm. More specifically, for example, when the depth h0 is 0.1 mm, the width w7 may be 0.3 mm to 1.5 mm, preferably 0.5 mm to 1.2 mm. Also, at this time, when the depth d1 is 0.15 mm, the width w9 may be 1.3 mm to 10 mm, preferably 1.5 mm to 6 mm. In this way, by making the depth d1 of the lower injection channel recess 17 deeper than the depth h0 of the lower vapor channel recess 12, degassing from the sealed space 3 to the lower injection channel recess 17 and injection of the working fluid 2 from the lower injection channel recess 17 to the sealed space 3 can be performed quickly. Note that the depth d1 of the lower injection channel recess 17 refers to the depth at the deepest part of the lower injection channel recess 17, and refers to the maximum distance (distance in the Z direction) between the upper surface 10a of the lower metal sheet 10 and the bottom surface 17b of the lower injection channel recess 17. In the present embodiment, the depth d1 of the lower injection channel recess 17 corresponds to the depth of the lower injection channel recess 17 in the inlet region 52 and the intermediate region 53. Also, the depth h0 of the lower vapor channel recess 12 refers to the depth at the deepest part of the lower vapor channel recess 12.

[0052] As shown in Fig. 7, the depth d1 of the lower injection channel recess 17 is the same in the inlet region 52 and the intermediate region 53. However, it is not limited to this, and the depth of the lower injection channel recess 17 in the inlet region 52 may be deeper than the depth of the lower injection channel recess 17 in the intermediate region 53. Further, the depth d2 of the lower injection channel recess 17 in the caulking region 54 is shallower than the depth d1 of the lower injection channel recess 17 in the inlet region 52 and the intermediate region 53. Thereby, the plurality of protrusions 56 can be easily crushed by caulking, and the sealed space 3 into which the working fluid 2 is injected can be sealed more reliably. Note that when closing the injection channel using a method other than caulking, such as soldering, the caulking region 54 does not have to be provided.

[0053] Next, the configuration of the upper metal sheet 20 will be described. In the present embodiment, the upper metal sheet 20 is different from the lower metal sheet 10 in that the liquid flow path portion 30 described later is not provided and the configuration of the upper injection protrusion 25 is different. The configuration of the upper metal sheet 20 will be described in more detail below.

[0054] As shown in FIGS. 3 and 5, the upper metal sheet 20 has an upper vapor flow path recess 21 (second vapor flow path portion) provided on the lower surface 20a. This upper vapor flow path recess 21 constitutes a part of the sealed space 3 and is mainly configured to diffuse and cool the vapor generated in the evaporation portion 11. More specifically, the vapor in the upper vapor flow path recess 21 diffuses in a direction away from the evaporation portion 11, and most of the vapor is transported toward the peripheral portion having a relatively low temperature. Further, as shown in FIG. 3, a housing member Ha that constitutes a part of the housing of a mobile terminal or the like is disposed on the upper surface 20b of the upper metal sheet 20. Thereby, the vapor in the upper vapor flow path recess 21 is cooled by the outside air via the upper metal sheet 20 and the housing member Ha.

[0055] In the present embodiment, as shown in FIGS. 2, 3, and 5, a plurality of upper flow path wall portions 22 (second flow path wall portions, second flow path protrusions) protruding downward (in a direction perpendicular to the bottom surface 21a) from the bottom surface 21a of the upper vapor flow path recess 21 are provided in the upper vapor flow path recess 21 of the upper metal sheet 20. In the present embodiment, an example is shown in which the upper flow path wall portions 22 extend in an elongated shape along the first direction X (the left - right direction in FIG. 5) of the vapor chamber 1. The upper flow path wall portion 22 includes a flat lower surface 22a (contact surface, protruding end surface) that contacts the upper surface 10a of the lower metal sheet 10 (more specifically, the upper surface 13a of the lower flow path wall portion 13 described above). Further, the upper flow path wall portions 22 are spaced apart at equal intervals and arranged parallel to each other.

[0056] As shown in FIGS. 3 and 5, the upper steam flow path recess 21 includes a plurality of upper steam passages 83 (second steam passages) partitioned by the upper flow path wall portions 22. The upper steam passages 83 extend in an elongated shape along the first direction X and are arranged parallel to each other. Both ends of each upper steam passage 83 communicate with an upper connecting steam passage 84 that extends in an elongated shape along the second direction Y, and each upper steam passage 83 communicates via the upper connecting steam passage 84. In this way, the steam of the working fluid 2 flows around each upper flow path wall portion 22 (the upper steam passage 83 and the upper connecting steam passage 84), and the steam is configured to be transported toward the peripheral edge of the upper steam flow path recess 21, suppressing the obstruction of the steam flow. In FIG. 3, the cross-sectional shape (the cross-section in the second direction Y) of the upper steam passage 83 of the upper steam flow path recess 21 is rectangular. However, it is not limited to this, and the cross-sectional shape of the upper steam passage 83 may be, for example, curved, semi-circular, or V-shaped, as long as it can diffuse the steam of the working fluid 2. The same applies to the cross-sectional shape of the upper connecting steam passage 84. The width (dimension in the second direction Y) of the upper steam passage 83 and the width of the upper connecting steam passage 84 may be the same as the width of the lower steam passage 81 and the width of the lower connecting steam passage 82 as shown in FIG. 3 and the like, but they may also be different.

[0057] The upper flow path wall portion 22 is arranged so as to overlap the corresponding lower flow path wall portion 13 of the lower metal sheet 10 in plan view, aiming to improve the mechanical strength of the vapor chamber 1. Further, the upper steam passage 83 is formed so as to overlap the corresponding lower steam passage 81 in plan view. Similarly, the upper connecting steam passage 84 is formed so as to overlap the corresponding lower connecting steam passage 82 in plan view.

[0058] Note that it is preferable that the width and height of the upper flow path wall portion 22 are the same as the width w0 and height h0 of the lower flow path wall portion 13 described above, respectively. Here, the bottom surface 21a of the upper steam flow path recess 21 can also be referred to as the ceiling surface in the vertical arrangement relationship between the lower metal sheet 10 and the upper metal sheet 20 as shown in FIG. 3, but since it corresponds to the back side surface of the upper steam flow path recess 21, it is referred to as the bottom surface 21a in this specification.

[0059] As shown in FIGS. 3 and 5, an upper peripheral wall 23 is provided at the peripheral edge of the upper metal sheet 20. The upper peripheral wall 23 is formed so as to surround the sealed space 3, particularly the upper vapor flow path recess 21, and defines the sealed space 3. Further, upper alignment holes 24 for positioning the lower metal sheet 10 and the upper metal sheet 20 are provided at the four corners of the upper peripheral wall 23 in plan view. That is, each upper alignment hole 24 is arranged to overlap with each of the above-described lower alignment holes 15 during temporary fixing described later, and is configured to enable positioning of the lower metal sheet 10 and the upper metal sheet 20.

[0060] The upper injection protrusion 25 is configured to be able to inject the liquid working fluid 2 into the sealed space 3 by covering the lower injection flow path recess 17 of the lower injection protrusion 16 from above. The upper injection protrusion 25 is formed to protrude outward from the end face of the upper metal sheet 20 in plan view. Note that the upper injection protrusion 25 is formed at a position overlapping the lower injection protrusion 16 when the lower metal sheet 10 and the upper metal sheet 20 are joined to each other.

[0061] No injection flow path recess is formed on the lower surface of the upper injection protrusion 25. For this reason, the upper injection protrusion 25 is formed in a flat shape without unevenness as a whole. That is, the upper injection protrusion 25 is an area that is not etched by an etching process described later as a whole, and the lower surface of the upper injection protrusion 25 is formed on the same plane as the lower surface 20a of the upper metal sheet 20.

[0062] Note that, without being limited to this, an upper injection flow path recess (injection flow path recess) having a shape that is mirror-symmetrical to the shape of the lower injection flow path recess 17 may be formed on the lower surface of the upper injection protrusion 25. Alternatively, an upper injection flow path recess (injection flow path recess) may be formed on the lower surface of the upper injection protrusion 25, and the lower injection flow path recess 17 may not be formed on the lower injection protrusion 16.

[0063] Such a lower metal sheet 10 and an upper metal sheet 20 are preferably diffusion-bonded and permanently joined to each other. More specifically, as shown in FIG. 3, the upper surface 14a of the lower peripheral wall 14 of the lower metal sheet 10 abuts against the lower surface 23a of the upper peripheral wall 23 of the upper metal sheet 20, and the lower peripheral wall 14 and the upper peripheral wall 23 are joined to each other. As a result, a sealed space 3 in which the working fluid 2 is sealed is formed between the lower metal sheet 10 and the upper metal sheet 20. Further, the upper surface 13a of the lower flow path wall portion 13 of the lower metal sheet 10 abuts against the lower surface 22a of the upper flow path wall portion 22 of the upper metal sheet 20, and each lower flow path wall portion 13 and the corresponding upper flow path wall portion 22 are joined to each other. This improves the mechanical strength of the vapor chamber 1. In particular, since the lower flow path wall portions 13 and the upper flow path wall portions 22 according to the present embodiment are arranged at equal intervals, the mechanical strength at each position of the vapor chamber 1 can be equalized. Note that the lower metal sheet 10 and the upper metal sheet 20 may be joined by another method such as soldering as long as they can be permanently joined, not by diffusion bonding. The term "permanently joined" is not bound by a strict meaning, and is used as a term meaning that the upper surface 10a of the lower metal sheet 10 and the lower surface 20a of the upper metal sheet 20 are joined to such an extent that the sealing performance of the sealed space 3 can be maintained during the operation of the vapor chamber 1.

[0064] Next, the configuration of the liquid flow path portion 30 will be described in more detail with reference to FIGS. 8 and 9. FIG. 8 is an enlarged plan view of the liquid flow path portion 30, and FIG. 9 is a cross-sectional view of the liquid flow path portion 30.

[0065] As described above, a liquid flow path portion 30 through which the liquid working fluid 2 passes is provided on the upper surface 10a of the lower metal sheet 10 (more specifically, the upper surface 13a of each lower flow path wall portion 13). The liquid flow path portion 30 forms a part of the sealed space 3 described above and communicates with the lower vapor flow path recess 12 and the upper vapor flow path recess 21. Note that the liquid flow path portion 30 is not necessarily provided in all the lower flow path wall portions 13. For example, there may be a lower flow path wall portion 13 in which the liquid flow path portion 30 is not provided.

[0066] As shown in FIG. 8, the liquid flow path portion 30 has a plurality of main flow grooves 31 extending parallel to each other and communication grooves 32 connecting adjacent main flow grooves 31. Among these, the main flow grooves 31 extend along the main flow direction of the working fluid 2 (in this case, the first direction X). Further, the communication grooves 32 extend along a direction orthogonal to the main flow direction of the working fluid 2 (in this case, the second direction Y), and the working fluid 2 can flow back and forth between adjacent main flow grooves 31. Liquid working fluid 2 passes through the main flow grooves 31 and the communication grooves 32, respectively. The main flow grooves 31 and the communication grooves 32 mainly serve to transport the working fluid 2 condensed from the vapor generated in the evaporation section 11 toward the evaporation section 11.

[0067] Further, a plurality of convex portions 33 are arranged in a staggered pattern in a plan view in the liquid flow path portion 30. Each convex portion 33 is formed so as to be surrounded by the main flow groove 31 and the communication groove 32, respectively. In FIG. 8, the plurality of convex portions 33 have the same shape as each other, and each convex portion 33 is formed in a rectangular shape such that the first direction X is the longitudinal direction in a plan view. In the present embodiment, the arrangement pitch of the convex portions 33 along the main flow direction of the working fluid 2 (in this case, the first direction X) is constant. That is, the plurality of convex portions 33 are arranged at regular intervals in the first direction X, and with respect to the convex portions 33 adjacent in the second direction Y, they are arranged with a shift of approximately half the length of the convex portion 33 in the first direction X.

[0068] It is preferable that the width (dimension in the second direction Y) w1 of the main flow groove 31 is larger than the width (dimension in the second direction Y) w2 of the convex portion 33. In this case, the ratio of the main flow groove 31 in the upper surface 13a of the lower flow path wall portion 13, the upper surface 14a of the lower peripheral wall 14, and the lower surface 23a of the upper peripheral wall 23 can be increased. For this reason, the cross-sectional area of the main flow groove 31 in the lower flow path wall portion 13 can be increased, and the transport function of the liquid working fluid 2 can be improved. For example, the width w1 of the main flow groove 31 may be 20 μm to 200 μm, and the width w2 of the convex portion 33 may be 20 μm to 180 μm.

[0069] It is preferable that the depth h1 of the main flow channel 31 is smaller than the height h0 of the lower flow channel wall portion 13 described above (see FIG. 3). In this case, the capillary action of the main flow channel 31 can be enhanced. For example, the depth h1 of the main flow channel 31 is preferably about half of the height h0 of the lower flow channel wall portion 13, and may be 5 μm to 200 μm.

[0070] Also, it is preferable that the width (dimension in the first direction X) w3 of the communication groove 32 is smaller than the width w1 of the main flow channel 31. Thereby, while the liquid working fluid 2 is being transported toward the evaporation portion 11 in each main flow channel 31, it is possible to suppress the working fluid 2 from flowing into the communication groove 32, and the transport function of the working fluid 2 can be improved. On the other hand, when dry-out occurs in any of the main flow channels 31, the working fluid 2 can be moved from the adjacent main flow channel 31 through the corresponding communication groove 32, quickly eliminating the dry-out and ensuring the transport function of the working fluid 2. That is, as long as the communication groove 32 can communicate between adjacent main flow channels 31, even if it is smaller than the width of the main flow channel 31, its function can be exerted. The width w3 of such a communication groove 32 may be, for example, 180 μm.

[0071] The depth of the communication groove 32 (not shown) may be shallower than the depth of the main flow channel 31 according to its width w3. For example, the depth of the communication groove 32 may be 10 μm to 200 μm. Also, the cross-sectional shape of the main flow channel 31 is not particularly limited, and can be, for example, rectangular, C-shaped, semi-circular, semi-elliptical, curved, or V-shaped. The same applies to the cross-sectional shape of the communication groove 32.

[0072] As shown in FIG. 9, the liquid flow path portion 30 is formed on the upper surface 13a of the lower flow path wall portion 13 of the lower metal sheet 10. On the other hand, in the present embodiment, the lower surface 22a of the upper flow path wall portion 22 of the upper metal sheet 20 is formed in a flat shape. As a result, each main flow groove 31 of the liquid flow path portion 30 is covered by the flat lower surface 22a. In this case, as shown in FIG. 9, a pair of side walls 35 and 36 of the main flow groove 31 extending in the first direction X and the lower surface 22a of the upper flow path wall portion 22 can form a pair of right-angled or acute-angled corners 37, and the capillary action at these corners 37 can be enhanced.

[0073] In the present embodiment, the liquid flow path portion 30 is formed only on the lower metal sheet 10. On the other hand, the vapor flow path recesses 12 and 21 are respectively formed on both the lower metal sheet 10 and the upper metal sheet 20. However, the present invention is not limited to this, and the liquid flow path portion 30 and the vapor flow path recesses 12 and 21 may be formed on at least one of the lower metal sheet 10 and the upper metal sheet 20.

[0074] Note that the shape of the liquid flow path portion 30 of the lower metal sheet 10 is not limited to the above.

[0075] For example, as shown in FIG. 10, the liquid flow path portion 30 may have a plurality of main flow grooves 31 extending parallel to each other and elongated convex portions 33A formed between the adjacent main flow grooves 31. In this case, each convex portion 33A extends along the main flow direction of the working fluid 2 (in this case, the first direction X) over substantially the entire longitudinal direction of the liquid flow path portion 30. As a result, the liquid working fluid 2 can be efficiently transported toward the evaporation portion 11 in each main flow groove 31. Although not shown, a communication groove may be provided in a part of the convex portion 33A, and each main flow groove 31 may be communicated with the lower vapor flow path recess 12 or the upper vapor flow path recess 21 by this communication groove.

[0076] As materials for the lower metal sheet 10 and the upper metal sheet 20, there are no particular limitations as long as the materials have good thermal conductivity. For example, it is preferable to use copper (oxygen-free copper), copper alloy, aluminum, or stainless steel. In this case, the thermal conductivity of the lower metal sheet 10 and the upper metal sheet 20 can be increased, and the heat dissipation efficiency of the vapor chamber 1 can be enhanced. Also, the thickness of the vapor chamber 1 may be set to 0.1 mm to 2.0 mm. In FIG. 3, the case where the thickness T1 of the lower metal sheet 10 and the thickness T2 of the upper metal sheet 20 are equal is shown, but it is not limited thereto, and the thickness T1 of the lower metal sheet 10 and the thickness T2 of the upper metal sheet 20 may not be equal.

[0077] Next, the operation of the present embodiment having such a configuration will be described. Here, first, the manufacturing method of the vapor chamber 1 will be described with reference to FIGS. 11(a) to (c) and FIGS. 12(a) to (c), but the description of the half-etching process of the upper metal sheet 20 will be simplified. Note that FIGS. 11(a) to (c) and FIGS. 12(a) to (c) show the same cross-section as the cross-sectional view of FIG. 3.

[0078] First, as shown in FIG. 11(a), as a preparation step, a flat metal material sheet M is prepared.

[0079] Subsequently, as shown in FIG. 11(b), resist films 41 are formed on the upper surface Ma and the lower surface Mb of the metal material sheet M by photolithography, respectively. The resist film 41 formed on the upper surface Ma of the metal material sheet M has a pattern shape corresponding to the lower flow path wall portion 13 and the lower peripheral wall 14.

[0080] Next, as shown in Fig. 11(c), the metal material sheet M is half-etched to form the lower steam flow path recess 12 that constitutes a part of the sealed space 3. As a result, the portion of the upper surface Ma of the metal material sheet M corresponding to the resist opening 41a of the resist film 41 is half-etched. Then, the resist film 41 is removed from the metal material sheet M. As a result, as shown in Fig. 11(c), the lower steam flow path recess 12, the lower flow path wall portion 13, and the lower peripheral wall 14 are formed. At the same time, the liquid flow path portion 30 is formed in the lower flow path wall portion 13 by half-etching. Since the widths of the portions of the resist opening 41a corresponding to the main flow groove 31 and the connection groove 32 of the liquid flow path portion 30 are narrow, the intrusion of the etching liquid is small. For this reason, the depths of the main flow groove 31 and the connection groove 32 are formed shallower than the depth of the lower steam flow path recess 12. Also, at this time, the lower injection flow path recess 17 shown in Figs. 2 and 4 is simultaneously formed by etching, and the lower metal sheet 10 having a predetermined outer contour shape as shown in Fig. 4 is obtained.

[0081] Note that half-etching means etching the material to be etched halfway in the thickness direction to form a recess that does not penetrate the material to be etched. Therefore, the depth of the recess formed by half-etching is not limited to half of the thickness of the material to be etched. The thickness of the material to be etched after half-etching is, for example, 30% to 70%, preferably 40% to 60% of the thickness of the material to be etched before half-etching. As the etching liquid, for example, an iron chloride-based etching liquid such as an aqueous solution of ferric chloride or a copper chloride-based etching liquid such as an aqueous solution of copper chloride can be used.

[0082] Note that the lower steam flow path recess 12 may be first formed in the metal material sheet M by half-etching (the first half-etching step), and then the liquid flow path portion 30 may be formed in the metal material sheet M in another etching step (the second half-etching step).

[0083] On one hand, although not shown in the figure, in the same manner as the lower metal sheet 10, the upper metal sheet 20 is half-etched from the lower surface 20a to form an upper steam flow path recess 21, an upper flow path wall portion 22, and an upper peripheral wall 23. In this way, the above-described upper metal sheet 20 is obtained.

[0084] Next, as shown in Fig. 12(a), as a temporary fixing step, the lower metal sheet 10 having the lower steam flow path recess 12 and the upper metal sheet 20 having the upper steam flow path recess 21 are opposed to each other and temporarily fixed.

[0085] In this case, first, the lower metal sheet 10 and the upper metal sheet 20 are positioned by using the lower alignment hole 15 (see Figs. 2 and 4) of the lower metal sheet 10 and the upper alignment hole 24 (see Figs. 2 and 5) of the upper metal sheet 20. Subsequently, the lower metal sheet 10 and the upper metal sheet 20 are fixed. The fixing method is not particularly limited. For example, the lower metal sheet 10 and the upper metal sheet 20 may be fixed by performing resistance welding on the lower metal sheet 10 and the upper metal sheet 20. In this case, as shown in Fig. 12(a), it is preferable to perform spot resistance welding using the electrode bar 40. Laser welding may be performed instead of resistance welding. Alternatively, ultrasonic waves may be irradiated to ultrasonically bond and fix the lower metal sheet 10 and the upper metal sheet 20. Furthermore, an adhesive may be used, but it is preferable to use an adhesive that does not have an organic component or has a small amount of organic components. In this way, the lower metal sheet 10 and the upper metal sheet 20 are fixed in a positioned state.

[0086] After temporary fixing, as shown in FIG. 12(b), as a permanent joining step, the lower metal sheet 10 and the upper metal sheet 20 are permanently joined by diffusion bonding. Diffusion bonding is a method in which the lower metal sheet 10 and the upper metal sheet 20 to be joined are brought into close contact, and in a controlled atmosphere such as in a vacuum or an inert gas, pressure is applied in the direction of bringing the metal sheets 10 and 20 into close contact and they are heated, and joining is performed using the diffusion of atoms occurring on the joining surface. In diffusion bonding, the materials of the lower metal sheet 10 and the upper metal sheet 20 are heated to a temperature close to the melting point, but since it is lower than the melting point, it is possible to avoid the lower metal sheet 10 and the upper metal sheet 20 from melting and deforming. More specifically, the upper surface 14a of the lower peripheral wall 14 of the lower metal sheet 10 and the lower surface 23a of the upper peripheral wall 23 of the upper metal sheet 20 become the joining surface and are diffusion bonded. Thereby, a sealed space 3 is formed between the lower metal sheet 10 and the upper metal sheet 20 by the lower peripheral wall 14 and the upper peripheral wall 23. Further, an injection flow path for the working fluid 2 communicating with the sealed space 3 is formed by the lower injection flow path recess 17 (see FIGS. 2 and 4) of the lower injection protrusion 16 and the upper injection protrusion 25 (see FIGS. 2 and 5). Furthermore, the upper surface 13a of the lower flow path wall portion 13 of the lower metal sheet 10 and the lower surface 22a of the upper flow path wall portion 22 of the upper metal sheet 20 become the joining surface and are diffusion bonded, improving the mechanical strength of the vapor chamber 1. The liquid flow path portion 30 formed on the upper surface 13a of the lower flow path wall portion 13 remains as a flow path for the liquid working fluid 2.

[0087] After permanent joining, as shown in FIG. 12(c), as an encapsulation step, the working fluid 2 is injected into the sealed space 3 from the injection portion 4 (see FIG. 2). At this time, first, the sealed space 3 is evacuated and depressurized (for example, 5 Pa or less, preferably 1 Pa or less), and then the working fluid 2 is injected into the sealed space 3. At the time of injection, the working fluid 2 passes through the injection flow path formed by the lower injection flow path recess 17 of the lower injection protrusion 16 and the upper injection protrusion 25. For example, the filling amount of the working fluid 2 may be 10% to 40% with respect to the total volume of the sealed space 3, although it also depends on the configuration of the liquid flow path portion 30 inside the vapor chamber 1. As described above, the width w9 of the lower injection flow path recess 17 constituting the injection flow path is wider than the width w7 of the lower vapor passage 81 (see FIG. 4). Therefore, the operations of evacuating the injection flow path to depressurize the sealed space 3 and injecting the working fluid 2 from the injection flow path into the sealed space 3 can be efficiently performed in a short time.

[0088] Here, if the evacuation time of the sealed space 3 is shortened, there is a possibility that non-condensable gas (for example, air, etc.) in the sealed space 3 may remain without being extracted from the sealed space 3. Also, if the injection time of the working fluid 2 becomes long, there is also a possibility that non-condensable gas may enter the sealed space 3 together with the working fluid 2. If non-condensable gas remains in the sealed space 3, it can inhibit the movement of the vapor of the working fluid 2 and the liquid working fluid 2 during the operation of the vapor chamber 1. In this case, it becomes difficult to obtain the desired heat transfer efficiency. In the heat transfer test of the vapor chamber 1, if the desired heat transfer efficiency cannot be obtained, the vapor chamber 1 is determined to be a defective product, and as a result, there is a problem that the yield may decrease. The heat transfer test is a test for applying heat to the vapor chamber 1, measuring the temperature of each part, and confirming whether heat transfer is normally performed inside the vapor chamber 1 from the measurement results of the temperature (see, for example, Japanese Patent Application Laid-Open No. 2004-301475).

[0089] In contrast, in the present embodiment, as described above, the width w9 of the lower injection channel recess 17 that constitutes the injection channel is wider than the width w7 of the lower vapor passage 81. Therefore, operations such as evacuating the injection channel to reduce the pressure in the sealed space 3 and injecting the working fluid 2 from the injection channel into the sealed space 3 can be efficiently performed in a short time. As a result, it is possible to prevent non-condensable gas from remaining in the sealed space 3, prevent a decrease in heat transfer efficiency, and thus improve the yield.

[0090] After the injection of the working fluid 2, the above-described injection channel is sealed. In this case, for example, by caulking the caulking region 54 of the lower injection channel recess 17, the plurality of protrusions 56 are deformed so as to be crushed. Thereby, the injection portion 4 is blocked to seal the injection channel, and the sealing of the sealed space 3 is completed. Alternatively, the injection portion 4 may be irradiated with a laser to partially melt the injection portion 4 to seal the injection channel. Alternatively, the injection portion 4 may be blocked by brazing to seal the injection channel. Thereby, the communication between the sealed space 3 and the outside air is blocked, and the working fluid 2 is sealed in the sealed space 3. In this way, the working fluid 2 in the sealed space 3 is prevented from leaking to the outside. Further, in order to more surely seal the injection portion 4, laser irradiation or brazing may be performed after caulking the caulking region 54. Further, after sealing the injection channel, the injection portion 4 may be cut at an arbitrary position on the side of the opening 17a rather than the caulking region 54 of the injection portion 4.

[0091] As described above, the vapor chamber 1 according to the present embodiment is obtained.

[0092] In the present embodiment, an example in which the vapor chamber 1 is mainly manufactured by etching has been described. However, the present invention is not limited to this, and it may be manufactured by a 3D printer. For example, the vapor chamber 1 may be manufactured by a 3D printer all at once, or each metal sheet 10, 20 may be manufactured separately by a 3D printer and then joined.

[0093] Next, an operation method of the vapor chamber 1, that is, a cooling method of the device D will be described.

[0094] The vapor chamber 1 obtained as described above is installed inside a housing such as a mobile terminal, and a device D such as a CPU, which is an object to be cooled, is attached to the lower surface 10b of the lower metal sheet 10. Since the amount of the working fluid 2 injected into the sealed space 3 is small, the liquid working fluid 2 in the sealed space 3 adheres to the wall surfaces of the sealed space 3, that is, the wall surfaces of the lower vapor flow path recess 12, the wall surfaces of the upper vapor flow path recess 21, and the wall surfaces of the liquid flow path portion 30 due to its surface tension.

[0095] When the device D generates heat in this state, the working fluid 2 present in the evaporation portion 11 of the lower vapor flow path recess 12 receives heat from the device D. The received heat is absorbed as latent heat and the working fluid 2 evaporates (vaporizes), generating vapor of the working fluid 2. Most of the generated vapor diffuses within the lower vapor flow path recess 12 and the upper vapor flow path recess 21 that constitute the sealed space 3 (see the solid arrows in FIG. 4). The vapor within the upper vapor flow path recess 21 and the lower vapor flow path recess 12 moves away from the evaporation portion 11, and most of the vapor is transported toward the peripheral portion of the vapor chamber 1 where the temperature is relatively low. The diffused vapor dissipates heat to the lower metal sheet 10 and the upper metal sheet 20 and is cooled. The heat received by the lower metal sheet 10 and the upper metal sheet 20 from the vapor is transmitted to the outside air through the housing member Ha (see FIG. 3).

[0096] The steam radiates heat to the lower metal sheet 10 and the upper metal sheet 20, thereby losing the latent heat absorbed in the evaporation section 11 and condensing. The condensed liquid working fluid 2 adheres to the wall surface of the lower vapor flow passage recess 12 or the wall surface of the upper vapor flow passage recess 21. Here, since the working fluid 2 continues to evaporate in the evaporation section 11, the working fluid 2 in the portion of the liquid flow passage section 30 other than the evaporation section 11 is transported toward the evaporation section 11 (see the dashed arrow in FIG. 4). As a result, the liquid working fluid 2 adhering to the wall surface of the lower vapor flow passage recess 12 and the wall surface of the upper vapor flow passage recess 21 moves toward the liquid flow passage section 30 and enters the liquid flow passage section 30. Therefore, the working fluid 2 filled in the liquid flow passage section 30 obtains a driving force toward the evaporation section 11 due to the capillary action of each main stream groove 31, and is smoothly transported toward the evaporation section 11.

[0097] The working liquid 2 that reaches the evaporation section 11 is evaporated again by receiving heat from the device D. In this way, the working liquid 2 circulates through the vapor chamber 1 while repeating phase changes, i.e., evaporation and condensation, and transfers and releases the heat of the device D. As a result, the device D is cooled.

[0098] Thus, according to this embodiment, the width w9 of the lower injection flow path recess 17 is wider than the width w7 of the lower steam passage 81. Therefore, the cross section of the lower injection flow path recess 17 in the width direction (second direction Y) is wider than the cross section of the lower steam passage 81 in the width direction (second direction Y). This makes it possible to efficiently and quickly perform the operation of evacuating the injection flow path to degas the sealed space 3 and the operation of injecting the working fluid 2 into the sealed space 3 when manufacturing the vapor chamber 1. In particular, when the width w9 of the lower injection flow path recess 17 is set to 1.5 times or more the width w7 of the lower steam passage 81, such an effect can be obtained significantly.

[0099] Also, according to the present embodiment, since a plurality of support columns 55 project from the lower injection channel recess 17, deformation of the lower injection channel recess 17 can be suppressed. Thereby, during the manufacture of the vapor chamber 1, it is possible to prevent the deformation of the lower injection channel recess 17 from hindering the degassing operation in the sealed space 3 and the injection operation of the working fluid 2 into the sealed space 3, and the degassing operation and the injection operation can be efficiently performed.

[0100] Also, according to the present embodiment, a caulking region 54 is formed in the lower injection channel recess 17, and this caulking region 54 has a plurality of protrusions 56. After injecting the working fluid 2 into the sealed space 3, these plurality of protrusions 56 are crushed when the caulking region 54 is caulked. Thereby, the sealing of the sealed space 3 can be made more reliable.

[0101] Also, according to the present embodiment, since the depth d1 of the lower injection channel recess 17 is deeper than the depth h0 of the vapor flow channel recess 12, the cross-sectional area of the lower injection channel recess 17 in the width direction (second direction Y) is larger than the cross-sectional area of the lower vapor passage 81 in the width direction (second direction Y). Thereby, during the manufacture of the vapor chamber 1, the degassing operation in the sealed space 3 and the injection operation of the working fluid 2 into the sealed space 3 can be efficiently performed.

[0102] Furthermore, according to the present embodiment, the liquid flow path portion 30 has a plurality of main flow grooves 31 extending in parallel to each other and communication grooves 32 connecting the adjacent main flow grooves 31 to each other. Thereby, the liquid working fluid 2 flows back and forth between the adjacent main flow grooves 31, and the occurrence of dry-out in the main flow grooves 31 is suppressed. For this reason, capillary action is imparted to the working fluid 2 in each main flow groove 31, and the working fluid 2 is smoothly transported toward the evaporation portion 11.

[0103] Furthermore, according to the present embodiment, in the liquid flow path portion 30, a plurality of convex portions 33 are arranged in a staggered pattern in a plan view. Thereby, the capillary action acting on the working fluid 2 in the main flow groove 31 can be equalized in the width direction of the main flow groove 31. That is, since the plurality of convex portions 33 are arranged in a staggered pattern in a plan view, the communication grooves 32 are alternately connected to both sides of the main flow groove 31. For this reason, unlike the case where the communication grooves 32 are connected to the same positions on both sides of each main flow groove 31, it is possible to suppress the loss of the capillary action in the direction toward the evaporation portion 11 due to the communication grooves 32. Therefore, at the intersection of the main flow groove 31 and the communication groove 32, it is possible to suppress the reduction of the capillary action, and the capillary action can be continuously imparted to the working fluid 2 flowing toward the evaporation portion 11.

[0104] Also, since the sealed space 3 is depressurized as described above, the lower metal sheet 10 and the upper metal sheet 20 are subjected to the pressure in the direction of being recessed inward in the thickness direction from the outside air. Here, if the communication grooves 32 are connected to the same positions on both longitudinal sides of each main flow groove 31, it is conceivable that the lower metal sheet 10 and the upper metal sheet 20 are recessed inward in the thickness direction along the direction parallel to the communication grooves 32. In this case, the flow path cross-sectional area of each main flow groove 31 becomes smaller, and the flow path resistance of the working fluid 2 may increase. On the other hand, in the present embodiment, in the liquid flow path portion 30, a plurality of convex portions 33 are arranged in a staggered pattern in a plan view. Thereby, even when the lower metal sheet 10 and the upper metal sheet 20 are recessed inward in the thickness direction along the communication grooves 32, it is possible to prevent the recess from crossing the main flow groove 31, ensure the flow path cross-sectional area of the main flow groove 31, and suppress the flow of the working fluid 2 from being obstructed.

[0105] Next, with reference to FIGS. 13 and 14, each modification example of the vapor chamber will be described. In FIGS. 13 and 14, the same parts as those in FIGS. 1 to 12 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0106] (Modification Example 1) FIG. 13 shows a vapor chamber 1A according to a modification (Modification 1). In the vapor chamber 1A shown in FIG. 13, unlike the embodiments shown in FIGS. 1 to 12, an upper vapor flow path recess 21 is not formed in the upper metal sheet 20. Although not shown in FIG. 13, the width of the injection flow path recess (lower injection flow path recess 17 or upper injection flow path recess) is wider than the width of the lower vapor passage 81. In this case, the thickness of the upper metal sheet 20 can be reduced, and thereby the thickness of the entire vapor chamber 1 can be reduced.

[0107] (Modification 2) FIG. 14 shows a vapor chamber 1B according to another modification (Modification 2). In the vapor chamber 1B shown in FIG. 14, unlike the embodiments shown in FIGS. 1 to 12, the lower metal sheet 10 does not have a lower vapor flow path recess 12, and the liquid flow path portion 30 is provided on the upper surface 10a of the lower metal sheet 10. Further, the liquid flow path portion 30 is formed not only in the region of the upper surface 10a facing the upper flow path wall portion 22 but also in the region facing the upper vapor flow path recess 21. Although not shown in FIG. 14, the width of the injection flow path recess (lower injection flow path recess 17 or upper injection flow path recess) is wider than the width of the upper vapor flow path recess 21. In this case, the number of main flow grooves 31 constituting the liquid flow path portion 30 can be increased, and the transport function of the liquid working fluid 2 can be improved. However, the region where the liquid flow path portion 30 is formed is not limited to the region shown in FIG. 14 and is arbitrary as long as the transport function of the liquid working fluid 2 can be ensured. Also, the thickness of the lower metal sheet 10 can be reduced, and thereby the thickness of the entire vapor chamber 1 can be reduced.

[0108] (Modification 3) FIG. 15 is a view showing a vapor chamber 1C according to another modification (Modification 3), and corresponds to FIG. 7 described above. In the vapor chamber 1C shown in FIG. 15, unlike the embodiments shown in FIGS. 1 to 12, the shape of each protrusion 56 in the caulking region 54 is substantially the same as the shape of each support column 55 in the intermediate region 53. Further, the depth of the lower injection channel recess 17 in the caulking region 54 is the same as the depth d1 of the lower injection channel recess 17 in the inlet region 52 and the intermediate region 53. In this case, by widening the interval p3 between the protrusions 56 and deforming the lower injection channel recess 17, the degassing operation in the sealed space 3 and the injection operation of the working fluid 2 into the sealed space 3 can be efficiently performed.

[0109] (Modification 4) FIG. 16 is a view showing a vapor chamber 1D according to another modification (Modification 4), and corresponds to FIG. 7 described above. In the vapor chamber 1D shown in FIG. 16, unlike the embodiments shown in FIGS. 1 to 12, the depth d1 of the lower injection channel recess 17 is substantially uniform through the inlet region 52, the intermediate region 53, and the caulking region 54, and is the same as the depth h0 of the vapor flow channel recess 12. In this case, since the depth d1 of the lower injection channel recess 17 and the depth h0 of the vapor flow channel recess 12 are the same, the degassing operation in the sealed space 3 and the injection operation of the working fluid 2 into the sealed space 3 can be smoothly performed by deforming the lower injection channel recess 17.

[0110] (Second Embodiment) Next, with reference to FIGS. 17 to 19, a vapor chamber, an electronic device, and a metal sheet for a vapor chamber in the second embodiment of the present invention will be described.

[0111] In the second embodiment shown in FIGS. 17 to 19, an intermediate metal sheet is interposed between the lower metal sheet and the upper metal sheet. A vapor flow path recess is formed in one of the lower metal sheet and the upper metal sheet, and a liquid flow path portion is formed in the other. The main difference is that the intermediate metal sheet is provided with a communication portion that connects the vapor flow path recess and the liquid flow path portion. Other configurations are substantially the same as those of the first embodiment shown in FIGS. 1 to 16. In FIGS. 17 to 19, the same parts as those of the first embodiment shown in FIGS. 1 to 16 are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0112] As shown in FIG. 17, in the present embodiment, an intermediate metal sheet 70 (third metal sheet) is interposed between a lower metal sheet 10 (first metal sheet) and an upper metal sheet 20 (second metal sheet). That is, in the vapor chamber 1 according to the present embodiment, the lower metal sheet 10, the intermediate metal sheet 70, and the upper metal sheet 20 are laminated in this order. The intermediate metal sheet 70 is provided on the lower metal sheet 10, and the upper metal sheet 20 is provided on the intermediate metal sheet 70. In FIG. 17, the illustration of the working fluid 2 is omitted for clarity of the drawing. The same applies to FIGS. 20, 22, and 25 described later.

[0113] The intermediate metal sheet 70 includes a lower surface 70a (first surface) provided on the side of the lower metal sheet 10 and an upper surface 70b (second surface) provided on the side opposite to the lower surface 70a and on the side of the upper metal sheet 20. Among these, the lower surface 70a is overlapped with the upper surface 10a of the lower metal sheet 10, and the upper surface 70b is overlapped with the lower surface 20a of the upper metal sheet 20. The lower metal sheet 10 and the intermediate metal sheet 70 are joined by diffusion bonding, and the intermediate metal sheet 70 and the upper metal sheet 20 are joined by diffusion bonding. The intermediate metal sheet 70 can be formed of the same material as the lower metal sheet 10 and the upper metal sheet 20. The thickness of the intermediate metal sheet 70 is, for example, 10 μm to 300 μm.

[0114] The sealed space 3 is formed between the lower metal sheet 10 and the upper metal sheet 20, and a part of the sealed space 3 is also formed in the intermediate metal sheet 70. In the present embodiment, the sealed space 3 mainly has a vapor flow path portion 80 through which the vapor of the working fluid 2 passes and a liquid flow path portion 30 through which the liquid working fluid 2 mainly passes. The vapor flow path portion 80 and the liquid flow path portion 30 communicate with each other so that the working fluid 2 can flow back. The vapor flow path portion 80 has a lower vapor flow path recess 12 (first vapor flow path portion) and an upper vapor flow path recess 21 (second vapor flow path portion).

[0115] The lower metal sheet 10 including the lower vapor flow path recess 12 and the liquid flow path portion 30 can have the same configuration as the lower metal sheet 10 in the first embodiment shown in FIGS. 1 to 16. Therefore, detailed description is omitted here.

[0116] In the present embodiment, the liquid flow path portion 30 is not provided in the upper metal sheet 20. Further, the upper metal sheet 20 has an upper vapor flow path recess 21 (second vapor flow path portion) provided on the lower surface 20a. A plurality of upper flow path protrusions 90 (second flow path protrusions) protruding downward (in a direction perpendicular to the bottom surface 21a) from the bottom surface 21a of the upper vapor flow path recess 21 are provided in the upper vapor flow path recess 21. The upper flow path protrusion 90 is a portion where the material of the upper metal sheet 20 remains without being etched in the half-etching process.

[0117] As shown in FIG. 17, the upper flow path protrusion 90 has a lower surface 90a located on the same plane as the lower surface 20a of the upper metal sheet 20. This lower surface 90a is in contact with the upper surface 70b of the intermediate metal sheet 70. This improves the mechanical strength of the vapor chamber 1 when the sealed space 3 is depressurized.

[0118] As shown in FIG. 18, in the present embodiment, the upper channel protrusions 90 are arranged in a staggered pattern in plan view. By doing so, the vapor of the working fluid 2 is configured to flow around the upper channel protrusions 90, suppressing the obstruction of the vapor flow. Further, the planar shape of the lower surface of the upper channel protrusion 90 is circular, and in this regard as well, the obstruction of the vapor flow of the working fluid 2 is suppressed. Note that the planar shape of the upper channel protrusion 90 is not limited to a circular shape as long as the obstruction of the vapor flow of the working fluid 2 can be suppressed.

[0119] As shown in FIG. 19, the intermediate metal sheet 70 is provided with communication holes 71 (communication portions) that communicate the upper vapor flow channel recess 21 and the liquid flow channel portion 30. The communication holes 71 penetrate the intermediate metal sheet 70 and constitute a part of the above-described sealed space 3. Further, the communication holes 71 are arranged between adjacent upper channel protrusions 90 in plan view, and the communication holes 71 are arranged in a staggered pattern in plan view.

[0120] As shown in FIG. 17, the communication holes 71 extend from the upper surface 70b to the lower surface 70a of the intermediate metal sheet 70. By doing so, the liquid working fluid 2 generated by condensation from the vapor of the working fluid 2 in the upper vapor flow channel recess 21 is configured to enter the main flow groove 31 of the liquid flow channel portion 30 through the communication holes 71. On the other hand, the vapor of the working fluid 2 evaporated in the evaporation section 11 can not only be diffused in the lower vapor flow channel recess 12 but also be diffused into the upper vapor flow channel recess 21 through the communication holes 71.

[0121] The communication hole 71 may be formed by etching from the upper surface 70b of the intermediate metal sheet 70. In this case, the communication hole 71 may be curved in a shape that bulges toward the lower surface 70a. Alternatively, the communication hole 71 may be etched from the lower surface 70a of the intermediate metal sheet 70, and in this case, it may be curved in a shape that bulges toward the upper surface 70b. Furthermore, the communication hole 71 may be formed by half etching from the lower surface 70a and half etching from the upper surface 70b. In this case, the shape or size of the portion of the communication hole 71 on the upper surface 70b side and the portion on the lower surface 70a side may be made different. In the present embodiment, as shown in FIG. 19, an example is shown in which the planar shape of the communication hole 71 is circular. When the diameter φ of the communication hole 71 is the minimum diameter in the range from the upper surface 70b to the lower surface 70a, the diameter φ of the communication hole 71 may be, for example, 50 μm to 2000 μm. Note that the planar shape of the communication hole 71 is not limited to a circular shape.

[0122] As shown in FIG. 19, in the present embodiment, the communication hole 71 overlaps a part of one of the pair of lower steam passages 81 adjacent to each other in plan view and a part of the other lower steam passage 81. Thus, the pair of lower steam passages 81 adjacent to each other communicate with each other via the communication hole 71. Therefore, the flow path cross-sectional area of the communication hole 71 can be increased, and the vapor of the working fluid 2 can be smoothly diffused into the upper steam flow path recess 21. Note that the communication hole 71 may overlap a part of each of three or more lower steam passages 81 to communicate these lower steam passages 81.

[0123] Also, as shown in FIG. 19, the intermediate metal sheet 70 is provided with intermediate alignment holes 72 for positioning the respective metal sheets 10, 20, 70. That is, each intermediate alignment hole 72 is arranged to overlap the respective lower alignment holes 15 and upper alignment holes 24 described above during temporary fixing, enabling positioning of the respective metal sheets 10, 20, 70.

[0124] Note that in this embodiment, the injection part 4 may be formed in the same manner as the injection part 4 of the first embodiment shown in FIGS. 1 to 16. That is, the lower metal sheet 10 has a lower injection protrusion 16, and a lower injection channel recess (injection channel recess) 17 is formed on the upper surface of the lower injection protrusion 16. The upper metal sheet 20 has an upper injection protrusion 25, but the lower surface of the upper injection protrusion 25 is formed in a flat shape without a recess formed thereon.

[0125] The intermediate metal sheet 70 has an intermediate injection protrusion 75 that protrudes laterally from the end face. However, no recesses are formed on the upper and lower surfaces of this intermediate injection protrusion 75, and it has the same thickness as the intermediate metal sheet 70 before processing. The upper and lower surfaces of the intermediate injection protrusion 75 are formed in a flat shape. The lower injection channel recess 17 and the intermediate injection protrusion 75 form an injection channel for the working fluid 2 integrally when the lower metal sheet 10 and the intermediate metal sheet 70 are joined. When the lower metal sheet 10, the upper metal sheet 20, and the intermediate metal sheet 70 are joined, the injection protrusions 16, 25, 75 overlap each other. The intermediate injection protrusion 75 can be formed in the same manner as the upper injection protrusion 25.

[0126] However, it is not limited to this. For example, in addition to or instead of the lower injection channel recess 17, an injection channel recess (injection channel recess) may be formed on the lower surface of the upper injection protrusion 25. Alternatively, instead of such an injection part 4, injection holes may be provided in the lower metal sheet 10 or the upper metal sheet 20, and the working fluid 2 may be injected through these injection holes.

[0127] Also, the vapor chamber 1 according to the present embodiment can be formed in the same manner as in the first embodiment shown in FIGS. 1 to 16, with the lower vapor flow path recess 12 and the liquid flow path portion 30 of the lower metal sheet 10 and the upper vapor flow path recess 21 of the upper metal sheet 20. Further, the communication hole 71 of the intermediate metal sheet 70 can also be formed by etching. Then, the lower metal sheet 10 and the upper metal sheet 20 are joined via the intermediate metal sheet 70. That is, the lower metal sheet 10 and the intermediate metal sheet 70 are diffusion-joined, and the upper metal sheet 20 and the intermediate metal sheet 70 are diffusion-joined. Thereby, the sealed space 3 is formed. Note that the lower metal sheet 10, the intermediate metal sheet 70, and the upper metal sheet 20 may be diffusion-joined at once.

[0128] Thus, according to the present embodiment, the intermediate metal sheet 70 is interposed between the lower metal sheet 10 and the upper metal sheet 20, the upper vapor flow path recess 21 is provided on the lower surface 20a of the upper metal sheet 20, and the liquid flow path portion 30 is provided on the upper surface 10a of the lower metal sheet 10. And, the intermediate metal sheet 70 is provided with the communication hole 71 that communicates the upper vapor flow path recess 21 and the liquid flow path portion 30. Thereby, even when the vapor chamber 1 is configured by the three metal sheets 10, 20, and 70, the working fluid 2 can be refluxed in the vapor chamber 1 while repeating phase changes in the sealed space 3, and the heat of the device D can be transferred and released. Further, since the upper vapor flow path recess 21 of the upper metal sheet 20 is widely communicated, the diffusion of the vapor of the working fluid 2 can be smoothly performed, and the heat transport efficiency can be improved.

[0129] Also, according to the present embodiment, similar to the first embodiment shown in FIGS. 1 to 16, the width w9 of the lower injection flow path recess 17 is wider than the width w7 of the lower vapor passage 81. Thereby, at the time of manufacturing the vapor chamber 1, the operations of evacuating the injection flow path to degas the sealed space 3 and then injecting the working fluid 2 into the sealed space 3 can be efficiently and quickly performed.

[0130] In the example shown in FIG. 17, an example is shown in which the cross-sectional shape of the lower steam flow path recess 12 and the cross-sectional shape of the upper steam flow path recess 21 are formed in a rectangular shape. However, the present invention is not limited to this, and the cross-sectional shapes of the steam flow path recesses 12 and 21 may be formed in a curved shape. The same applies to the main flow groove 31 and the communication groove 32 of the liquid flow path portion 30.

[0131] In the above-described embodiment, an example in which one intermediate metal sheet 70 is interposed between the lower metal sheet 10 and the upper metal sheet 20 has been described. However, the present invention is not limited to this, and two or more intermediate metal sheets 70 may be interposed between the lower metal sheet 10 and the upper metal sheet 20.

[0132] (Third Embodiment) Next, with reference to FIGS. 20 and 21, the vapor chamber, the electronic device, and the metal sheet for the vapor chamber in the third embodiment of the present invention will be described.

[0133] In the third embodiment shown in FIGS. 20 and 21, the main difference is that the upper flow path protrusion and the communication hole extend in an elongated shape along the first direction, and the other configurations are substantially the same as those of the second embodiment shown in FIGS. 17 to 19. In FIGS. 20 and 21, the same parts as those of the second embodiment shown in FIGS. 17 to 19 are denoted by the same reference numerals, and detailed description thereof is omitted.

[0134] As shown in FIG. 20, in the present embodiment, the upper flow path protrusion 90 (second flow path protrusion) provided on the upper metal sheet 20 is configured in the same manner as the upper flow path wall portion 22 in the first embodiment shown in FIGS. 1 to 16. Therefore, hereinafter, the upper flow path protrusion 90 will be referred to as the upper flow path wall portion 22, and detailed description of the upper metal sheet 20 including the upper flow path protrusion 90 will be omitted.

[0135] As shown in FIG. 21, in the present embodiment, the communication hole 71 provided in the intermediate metal sheet 70 is formed to extend in an elongated shape along the first direction X. Also in the present embodiment, the communication hole 71 is disposed between the upper flow path wall portions 22 adjacent to each other in plan view. The width w4 (dimension in the second direction Y) of the communication hole 71 may be, for example, 50 μm to 1500 μm. Here, the width w4 of the communication hole 71 is the minimum width in the range from the upper surface 70b to the lower surface 70a.

[0136] In the present embodiment, the communication hole 71 overlaps with one of the lower vapor passages 81 of the lower vapor flow path recess 12 in plan view. And in plan view, the upper vapor passage 83 of the upper vapor flow path recess 21 that overlaps with the lower vapor passage 81 also overlaps with the communication hole 71. That is, the communication hole 71 is provided so as to overlap with the lower vapor passage 81 and the upper vapor passage 83 that overlap with each other. For this reason, the vapor of the working fluid 2 in the lower vapor passage 81 can quickly reach the upper vapor passage 83 through the communication hole 71 and can smoothly diffuse into the upper vapor passage 83.

[0137] Thus, according to the present embodiment, the intermediate metal sheet 70 is interposed between the lower metal sheet 10 and the upper metal sheet 20, the upper vapor flow path recess 21 is provided on the lower surface 20a of the upper metal sheet 20, and the liquid flow path portion 30 is provided on the upper surface 10a of the lower metal sheet 10. And the communication hole 71 that communicates the upper vapor flow path recess 21 and the liquid flow path portion 30 is provided in the intermediate metal sheet 70. Thereby, even when the vapor chamber 1 is configured by the three metal sheets 10, 20, and 70, in the sealed space 3, the working fluid 2 can be refluxed in the vapor chamber 1 while repeating the phase change, and the heat of the device D can be transferred and released.

[0138] Also, according to the present embodiment, similar to the first embodiment shown in FIGS. 1 to 16, the width w9 of the lower injection channel recess 17 is wider than the width w7 of the lower vapor passage 81. As a result, during the manufacture of the vapor chamber 1, operations such as evacuating the injection channel to degas the sealed space 3 and then injecting the working fluid 2 into the sealed space 3 can be performed efficiently and quickly.

[0139] (Fourth Embodiment) Next, with reference to FIGS. 22 to 25, the vapor chamber, electronic device, and metal sheet for the vapor chamber according to the fourth embodiment of the present invention will be described.

[0140] In the fourth embodiment shown in FIGS. 22 to 25, an intermediate metal sheet is interposed between the lower metal sheet and the upper metal sheet, and a vapor flow path portion including a plurality of vapor passages is formed on at least one of the lower surface and the upper surface of the intermediate metal sheet, a liquid flow path portion is formed on at least one of the lower surface and the upper surface of the intermediate metal sheet, an injection liquid flow path portion is formed on at least one of the lower surface and the upper surface of the intermediate metal sheet, and the main difference is that the width of the injection flow path portion is wider than the width of the vapor passage. Other configurations are substantially the same as those of the second embodiment shown in FIGS. 17 to 19. In FIGS. 22 to 25, the same reference numerals are given to the same parts as those of the second embodiment shown in FIGS. 17 to 19, and detailed descriptions thereof are omitted.

[0141] As shown in FIG. 22, in the present embodiment, the vapor flow path portion 80 is provided on the upper surface 70b of the intermediate metal sheet 70. That is, the vapor flow path portion 80 according to the present embodiment is formed so as to extend from the upper surface 70b to the lower surface 70a of the intermediate metal sheet 70 and penetrates the intermediate metal sheet 70. The liquid flow path portion 30 is provided on the lower surface 70a of the intermediate metal sheet 70. Therefore, the intermediate metal sheet 70 according to the present embodiment may sometimes be referred to as a wick sheet. The vapor flow path portion 80 and the liquid flow path portion 30 communicate with each other so that the working fluid 2 can flow back.

[0142] As shown in FIGS. 23 and 24, the intermediate metal sheet 70 has a frame portion 73 formed in a rectangular frame shape in plan view and a plurality of land portions 74 provided within the frame portion 73. The frame portion 73 and the land portions 74 are portions where the material of the intermediate metal sheet 70 remains without being etched when the intermediate metal sheet 70 is etched. The land portions 74 extend in an elongated shape along the first direction X, and a plurality of them are arranged within the vapor flow path portion 80. The land portions 74 are supported by each other via a support portion (not shown) and are also supported by the frame portion 73. The support portion is formed so as to suppress the flow of the vapor of the working fluid 2 flowing in the intermediate vapor passage 85 described later from being obstructed. For example, the support portion may be formed in a part of the range from the upper surface 70b to the lower surface 70a of the intermediate metal sheet 70 in the vertical direction of FIG. 22.

[0143] The vapor flow path portion 80 includes a plurality of intermediate vapor passages 85 (third vapor passage, vapor passage) partitioned by the land portions 74. The intermediate vapor passages 85 extend in an elongated shape along the first direction X and are arranged parallel to each other. Both ends of each intermediate vapor passage 85 communicate with an intermediate connecting vapor passage 86 that extends in an elongated shape along the second direction Y, and each intermediate vapor passage 85 communicates with the intermediate connecting vapor passage 86. In this way, the vapor of the working fluid 2 flows around each land portion 74 (intermediate vapor passage 85 and intermediate connecting vapor passage 86), and the vapor is configured to be transported toward the peripheral edge portion of the vapor flow path portion 80, suppressing the vapor flow from being obstructed. In FIG. 22, the cross-sectional shape (cross-section in the second direction Y) of the intermediate vapor passage 85 is rectangular. However, it is not limited to this, and the cross-sectional shape of the intermediate vapor passage 85 may be, for example, curved, semi-circular, or V-shaped, as long as it can diffuse the vapor of the working fluid 2. The same applies to the intermediate connecting vapor passage 86. The intermediate vapor passage 85 and the intermediate connecting vapor passage 86 can be formed by etching in the same manner as the communication holes 71 in the second embodiment shown in FIGS. 17 to 19 and can have the same cross-sectional shape as the communication holes 71.

[0144] The width w5 (dimension in the second direction Y) of the land portion 74 of the intermediate metal sheet 70 may be, for example, 50 μm to 2000 μm when it is the maximum dimension in the range from the upper surface 70b to the lower surface 70a. The width w6 (dimension in the second direction Y) of the intermediate vapor passage 85 may be, for example, 50 μm to 2000 μm when it is the minimum dimension in the range from the upper surface 70b to the lower surface 70a. The same applies to the width (dimension in the first direction X) of the intermediate connecting vapor passage 86.

[0145] The liquid flow path portion 30 is provided in the land portion 74 on the lower surface 70a of the intermediate metal sheet 70. That is, the liquid flow path portion 30 is provided on the lower surface of the land portion 74.

[0146] On the upper surface 10a of the lower metal sheet 10 in the present embodiment, the lower vapor flow path recess 12 is not provided, and the liquid flow path portion 30 is not provided either. The upper surface 10a is formed in a flat shape. Similarly, on the lower surface 20a of the upper metal sheet 20, the upper vapor flow path recess 21 is not provided, and the liquid flow path portion 30 is not provided either. The lower surface 20a is formed in a flat shape. The thickness of the lower metal sheet 10 and the thickness of the upper metal sheet 20 according to the present embodiment are, for example, 8 μm to 100 μm.

[0147] Further, in the vapor chamber 1 according to the present embodiment, the vapor flow path portion 80 and the liquid flow path portion 30 of the intermediate metal sheet 70 can be formed by etching. Then, the lower metal sheet 10 and the upper metal sheet 20 are joined via the intermediate metal sheet 70. That is, the lower metal sheet 10 and the intermediate metal sheet 70 are diffusion-bonded, and the upper metal sheet 20 and the intermediate metal sheet 70 are diffusion-bonded. Thereby, the sealed space 3 is formed. Note that the lower metal sheet 10, the intermediate metal sheet 70, and the upper metal sheet 20 may be diffusion-bonded at once.

[0148] In addition, in the present embodiment, an intermediate injection channel portion 76 (injection channel portion) is formed in a concave shape on the lower surface of the intermediate injection protrusion 75 that constitutes the injection portion 4. On the upper surface of the lower injection protrusion 16, no lower injection channel recess 17 is formed, and the upper surface is formed in a flat shape. The lower injection protrusion 16 and the intermediate injection channel portion 76 form an injection channel for the working fluid 2 integrally when the lower metal sheet 10 and the intermediate metal sheet 70 are joined. As shown in FIG. 24, although no injection channel portion is formed on the upper surface of the intermediate injection protrusion 75, the intermediate injection channel portion 76 may be formed on the upper surface of the intermediate injection protrusion 75 in addition to or instead of the lower surface of the intermediate injection protrusion 75.

[0149] The intermediate injection protrusion 75 and the intermediate injection channel portion 76 can be formed in the same manner as the lower injection protrusion 16 and the lower injection channel recess 17 in the first embodiment. For example, the intermediate injection protrusion 75 may have the same width w8 and length L1 as the lower injection protrusion 16. Also, for example, the intermediate injection channel portion 76 may have the same width w9 as the lower injection channel recess 17.

[0150] In the present embodiment, the width w9 of the intermediate injection channel portion 76 may be wider than the width w6 of the intermediate vapor passage 85 described above. In this case, for example, the width w6 is 0.05 mm to 2.0 mm, and the width w9 is 1 mm to 10 mm. Also, the width w9 of the intermediate injection channel portion 76 is preferably 1.5 times or more the width w6 of the intermediate vapor passage 85. More specifically, for example, when the width w6 is 0.05 mm, the width w9 may be 1 mm to 6 mm, preferably 1 mm to 3 mm. Also, for example, when the width w6 is 2 mm, the width w9 may be 3.5 mm to 10 mm, preferably 1 mm to 6 mm. Thus, by making the width w9 of the intermediate injection channel portion 76 wider than the width w6 of the intermediate vapor passage 85, degassing from the sealed space 3 and injection of the working fluid 2 into the sealed space 3 can be performed quickly.

[0151] The intermediate injection flow path portion 76 is not necessarily formed in a concave shape. For example, the intermediate injection flow path portion 76 may extend from the lower surface 70a to the upper surface 70b of the intermediate metal sheet 70 and be formed so as to penetrate the intermediate metal sheet 70. In this case, the support column 55 may be supported by the earth retaining portion 51 via a support portion (not shown). The protrusion 56 may be formed in a columnar shape and supported by the earth retaining portion 51 via a support portion (not shown).

[0152] Thus, according to the present embodiment, the intermediate metal sheet 70 is interposed between the lower metal sheet 10 and the upper metal sheet 20, the vapor flow path portion 80 is provided on the upper surface 70b of the intermediate metal sheet 70, and the liquid flow path portion 30 is provided on the lower surface 70a of the intermediate metal sheet 70. Thereby, even when the vapor chamber 1 is configured by the three metal sheets 10, 20, and 70, the working fluid 2 can be refluxed in the vapor chamber 1 while repeating phase changes within the sealed space 3 to transfer and release the heat of the device D.

[0153] Further, according to the present embodiment, the vapor flow path portion 80 is provided on the upper surface 70b of the intermediate metal sheet 70 interposed between the lower metal sheet 10 and the upper metal sheet 20, and the liquid flow path portion 30 is provided on the lower surface 70a. Thereby, etching for forming vapor flow paths and liquid flow paths on the lower metal sheet 10 and the upper metal sheet 20 can be made unnecessary. That is, the number of members to be etched can be reduced. For this reason, the manufacturing process of the vapor chamber 1 can be simplified, and the vapor chamber 1 can be easily manufactured. Further, since the vapor flow path portion 80 and the liquid flow path portion 30 are formed in the intermediate metal sheet 70, the vapor flow path portion 80 and the liquid flow path portion 30 can be accurately positioned during the etching process. For this reason, it is not necessary to align the vapor flow path portion 80 and the liquid flow path portion 30 in the assembly process. As a result, the vapor chamber 1 can be easily manufactured. Further, the height (or depth) of the vapor flow path can be defined by the thickness of the intermediate metal sheet 70, and the vapor chamber 1 can be easily manufactured.

[0154] Further, according to the present embodiment, similar to the first embodiment shown in FIGS. 1 to 16, the width w9 of the intermediate injection channel portion 76 is wider than the width w6 of the intermediate vapor passage 85. Thereby, during the manufacture of the vapor chamber 1, operations such as evacuating the injection channel to degas the sealed space 3 and then injecting the working fluid 2 into the sealed space 3 can be efficiently and quickly performed.

[0155] Further, according to the present embodiment, the vapor flow path portion 80 extends from the upper surface 70b to the lower surface 70a of the intermediate metal sheet 70. This can reduce the flow path resistance of the vapor flow path portion 80. Therefore, the liquid working fluid 2 generated by condensing from the vapor of the working fluid 2 in the vapor flow path portion 80 can smoothly enter the main flow groove 31 of the liquid flow path portion 30. On the other hand, the vapor of the working fluid 2 evaporated in the evaporation portion 11 can smoothly diffuse into the vapor flow path portion 80.

[0156] In the above-described present embodiment, an example in which the liquid flow path portion 30 is provided on the lower surface 70a of the intermediate metal sheet 70 has been described. However, the present invention is not limited to this, and as shown in FIG. 25, the liquid flow path portion 30 may be provided not only on the lower surface 70a but also on the upper surface 70b. In this case, the flow paths for transporting the liquid working fluid 2 to the evaporation portion 11 or the portion of the intermediate metal sheet 70 close to the evaporation portion 11 can be increased, and the transport efficiency of the liquid working fluid 2 can be improved. Therefore, the heat transport efficiency of the vapor chamber 1 can be improved.

[0157] In the above-described present embodiment, an example in which the vapor flow path portion 80 is formed to extend from the upper surface 70b to the lower surface 70a of the intermediate metal sheet 70 has been described. However, the present invention is not limited to this, and the vapor flow path portion 80 may be formed in a concave shape on the upper surface 70b of the intermediate metal sheet 70, such as the lower vapor flow path recess 12 shown in FIGS. 1 to 16 or the upper vapor flow path recess 21 shown in FIGS. 17 and 18. In this case, a communication hole (not shown) that connects the vapor flow path portion 80 to the liquid flow path portion 30 may be provided in the intermediate metal sheet 70.

[0158] In addition, in the above-described embodiment, an example in which one intermediate metal sheet 70 is interposed between the lower metal sheet 10 and the upper metal sheet 20 has been described. However, the present invention is not limited to this, and other metal sheets (not shown) may be interposed between the lower metal sheet 10 and the intermediate metal sheet 70, or other metal sheets (not shown) may be interposed between the upper metal sheet 20 and the intermediate metal sheet 70.

[0159] The present invention is not limited to the above-described embodiments and each modification as they are, and at the implementation stage, the components can be modified and embodied without departing from the gist thereof. Further, various inventions can be formed by appropriately combining a plurality of components disclosed in the above-described embodiments and each modification. Some components may be deleted from all the components shown in each embodiment and each modification. Further, in the above-described embodiments and each modification, the configuration of the lower metal sheet 10 and the configuration of the upper metal sheet 20 may be interchanged.

Explanation of Reference Numerals

[0160] 1 vapor chamber 2 working fluid 10 lower metal sheet 12 lower vapor flow path recess 17 lower injection flow path recess 20 upper metal sheet 21 upper vapor flow path recess 30 liquid flow path portion 31 main flow groove 32 communication groove 33 convex portion 54 caulking region 55 support column 56 protrusion 70 intermediate metal sheet 70a lower surface 70b upper surface 71 communication hole 76 intermediate injection flow path portion 80 vapor flow path portion 81 lower vapor passage 85 intermediate vapor passage Upper flow path protrusion 90 D Device E Electronic device H Housing P Intersection Q Buffer region X First direction Y Second direction

Claims

【Claim 1】 A metal sheet for a vapor chamber having a sealed space filled with a working fluid, comprising: a first surface; a second surface provided on the side opposite to the first surface; wherein a vapor flow path portion through which vapor of the working fluid passes is formed on the first surface; an injection flow path recess for injecting the liquid working fluid is formed on the first surface; the injection flow path recess communicates with the vapor flow path portion at one end and is provided with an opening at the other end; a plurality of protrusions are formed in a first region of the injection flow path recess located on the vapor flow path portion side; a plurality of struts are formed in a second region of the injection flow path recess located on the opening side with respect to the first region; the interval between adjacent protrusions is narrower than the interval between adjacent struts; a metal sheet for a vapor chamber.

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