JP7371796B2 - Vapor chamber and mobile terminal - Google Patents

Description

The present invention relates to a vapor chamber having a sealed space in which a working fluid is sealed, and a metal sheet for a vapor chamber.

Devices that generate heat, such as central processing units (CPUs) used in mobile terminals such as mobile terminals and tablet terminals, are cooled by heat dissipation members such as heat pipes (for example, see Patent Documents 1 to 4). . In recent years, as mobile terminals and the like have become thinner, there has been a demand for thinner heat dissipation members, and progress is being made in developing vapor chambers that can be made thinner than heat pipes. A working fluid is sealed in the vapor chamber, and this working fluid cools the device by absorbing heat from the device and releasing it to the outside.

More specifically, the working fluid in the vapor chamber receives heat from the device in a portion close to the device (evaporation section) and evaporates into vapor, and then the vapor moves to a position away from the evaporation section. It is cooled and condensed into a liquid. Inside the vapor chamber, a liquid flow path recess is provided as a capillary structure (wick), and the liquefied working fluid passes through this liquid flow path recess, is transported to the evaporation section, and is returned to the evaporation section. Evaporates due to heat. In this way, the working fluid circulates in the vapor chamber while undergoing phase changes, that is, repeating evaporation and condensation, thereby transferring heat in the device and increasing heat transport efficiency.

Japanese Patent Application Publication No. 11-31768 Japanese Patent Application Publication No. 2007-212028 JP 2015-59693 Publication Japanese Patent Application Publication No. 2016-17702

In order to increase the heat transport efficiency of the vapor chamber, it is desirable to efficiently transport the working fluid in the vapor chamber to the evaporation section. In this case, the liquid flow path recess is required to have low flow resistance for the working fluid passing through the liquid flow path recess and high capillary action.

The present invention has been made in consideration of these points, and an object of the present invention is to provide a vapor chamber and a metal sheet for a vapor chamber that can enhance capillary action while reducing flow path resistance of a working fluid. .

The present invention
A vapor chamber having a sealed space in which a working fluid is sealed,
a first metal sheet;
a second metal sheet provided on the first metal sheet and forming the sealed space between the second metal sheet and the first metal sheet;
The first metal sheet is provided on a side surface of the second metal sheet, forms a part of the sealed space, and has a first vapor flow path recess through which the vapor of the working fluid passes, and a first vapor flow path recess through which the vapor of the working fluid passes. a first channel wall portion including a first contact surface that protrudes from the bottom surface of the channel recess and contacts the second metal sheet;
The first contact surface is provided with a first liquid flow path recess that constitutes a part of the sealed space and through which the liquid working fluid passes;
The first liquid flow path recess has a first recess opening and a first wide portion provided closer to the bottom of the first liquid flow path recess than the first recess opening,
In the cross section of the first liquid flow path recess, the width of the first wide portion is larger than the width of the first recess opening.
vapor chamber,
I will provide a.

In addition, in the vapor chamber mentioned above,
A cross section of the first liquid flow path recess is formed in an arc shape.
You can do it like this.

Moreover, in the vapor chamber mentioned above,
The second metal sheet is provided on a side surface of the first metal sheet, forms a part of the sealed space, and has a second steam passage recess through which the vapor of the working fluid passes, and a second steam flow path concave portion through which the vapor of the working fluid passes. a second channel wall portion including a second contact surface that protrudes from the bottom surface of the channel recess and contacts the first metal sheet;
The second contact surface is provided with a second liquid flow path recess that constitutes a part of the sealed space and through which the liquid working fluid passes;
The second liquid flow path recess has a second recess opening and a second wide portion provided closer to the bottom of the second liquid flow path recess than the second recess opening,
In the cross section of the second liquid flow path recess, the width of the second wide portion is larger than the width of the opening of the second recess.
You can do it like this.

Moreover, in the vapor chamber mentioned above,
the first liquid flow path recess and the second liquid flow path recess are opposed to each other;
You can do it like this.

Moreover, in the vapor chamber mentioned above,
A portion of the second contact surface is exposed in the first liquid flow path recess;
You can do it like this.

Moreover, in the vapor chamber mentioned above,
A portion of the first contact surface is exposed in the second liquid flow path recess;
You can do it like this.

Moreover, the present invention
A vapor chamber metal sheet for a vapor chamber having a sealed space in which a working fluid is sealed,
a vapor flow path recess that forms a part of the sealed space and through which the vapor of the working fluid passes;
a flow path wall portion including a protruding end surface that protrudes from the bottom surface of the vapor flow path recess,
A liquid flow path recess through which the liquid working fluid passes is provided on the protruding end surface;
The liquid flow path recess has a recess opening and a wide portion provided closer to the bottom of the liquid flow path recess than the recess opening,
In the cross section of the liquid flow path recess, the width of the wide portion is larger than the width of the recess opening.
metal sheet for vapor chamber,
I will provide a.

Furthermore, the present invention
A vapor chamber having a sealed space in which a working fluid is sealed,
a first metal sheet;
a second metal sheet provided on the first metal sheet and forming the sealed space between the second metal sheet and the first metal sheet;
The first metal sheet is provided on a side surface of the second metal sheet, forms a part of the sealed space, and has a first vapor flow path recess through which the vapor of the working fluid passes, and a first vapor flow path recess through which the vapor of the working fluid passes. a first channel wall portion including a first contact surface that protrudes from the bottom surface of the channel recess and contacts the second metal sheet;
The second metal sheet is provided on a side surface of the first metal sheet, forms a part of the sealed space, and has a second steam passage recess through which the vapor of the working fluid passes, and a second steam flow path concave portion through which the vapor of the working fluid passes. a second channel wall portion including a second contact surface that protrudes from the bottom surface of the channel recess and contacts the first metal sheet;
The first contact surface is provided with a first liquid flow path recess that constitutes a part of the sealed space and through which the liquid working fluid passes;
The second contact surface is provided with a second liquid flow path recess that constitutes a part of the sealed space and through which the liquid working fluid passes;
The first liquid flow path recess and the second liquid flow path recess face each other,
A portion of the second contact surface is exposed in the first liquid flow path recess, or a portion of the first contact surface is exposed in the second liquid flow path recess.
vapor chamber,
I will provide a.

In addition, in the vapor chamber mentioned above,
A portion of the second contact surface is exposed to the first liquid flow path recess, and a portion of the first contact surface is exposed to the second liquid flow path recess.
You can do it like this.

According to the present invention, it is possible to increase the capillary action while reducing the flow path resistance of the hydraulic fluid.

FIG. 1 is a top view showing a vapor chamber according to a first embodiment of the invention. FIG. 2 is a cross-sectional view taken along line AA, showing the vapor chamber of FIG. FIG. 3 is a top view of the lower metal sheet of FIG. FIG. 4 is a bottom view of the upper metal sheet of FIG. FIG. 5 is an enlarged top view of part B showing the liquid flow path recess in FIG. 3. FIG. FIG. 6 is an enlarged cross-sectional view of section C showing the liquid flow path recess in FIG. 2. FIG. FIG. 7 is a diagram for explaining a process of preparing a metal material sheet in the vapor chamber manufacturing method of FIG. 1. FIG. 8 is a diagram for explaining a half-etching process of a metal material sheet in the vapor chamber manufacturing method of FIG. 1. FIG. 9 is a diagram for explaining the step of forming a resist film on the upper surface of the metal material sheet in the half-etching step of FIG. 8. FIG. 10 is a diagram for explaining the resist film patterning step of FIG. 9 in the half-etching step of FIG. 8. FIG. 11 is a diagram for explaining the half-etching process of the metal material sheet in the half-etching process of FIG. 8. FIG. 12 is a diagram for explaining the resist film removal process in the half etching process of FIG. 8. FIG. 13 is a diagram for explaining a temporary fixing step in the vapor chamber manufacturing method of FIG. 1. FIG. 14 is a diagram for explaining a permanent bonding step in the method for manufacturing the vapor chamber of FIG. 1. FIG. 15 is a diagram for explaining a step of sealing in a hydraulic fluid in the method for manufacturing the vapor chamber of FIG. 1. FIG. 16 is a diagram showing a modification (modification 1) of FIG. 6. FIG. 17 is a diagram showing another modification (modification 2) of FIG. 6. FIG. 18 is an enlarged sectional view showing a liquid flow path recess in a vapor chamber according to a second embodiment of the present invention. FIG. 19 is a diagram showing a modification (modification 3) of FIG. 18. FIG. 20 is a diagram showing another modification (modification 4) of FIG. 18. FIG. 21 is a diagram showing another modification (modification 5) of FIG. 18. FIG. 22 is a diagram showing another modification (modification 6) of FIG. 18. FIG. 23 is a diagram showing another modification (modification 7) of FIG. 18.

Embodiments of the present invention will be described below with reference to the drawings. In addition, in the drawings attached to this specification, for convenience of illustration and ease of understanding, the scale, vertical and horizontal dimension ratios, etc. are appropriately changed and exaggerated from those of the actual drawings.

(First embodiment)
A vapor chamber and a vapor chamber metal sheet in a first embodiment of the present invention will be described with reference to FIGS. 1 to 17. The vapor chamber 1 in this embodiment has a sealed space 3 in which a hydraulic fluid 2 is sealed, and the hydraulic fluid 2 in the sealed space 3 repeatedly undergoes a phase change, thereby allowing mobile terminals such as mobile terminals and tablet terminals to This is a device for cooling a device D (device to be cooled) that generates heat, such as a central processing unit (CPU) used in a computer or the like. The vapor chamber 1 is generally formed into a thin flat plate shape.

As shown in FIGS. 1 and 2, the vapor chamber 1 includes a lower metal sheet 10 (first metal sheet) having an upper surface 10a, and an upper metal sheet 20 (second metal sheet) provided on the lower metal sheet 10. sheet) and. Both the lower metal sheet 10 and the upper metal sheet 20 correspond to vapor chamber metal sheets. The upper metal sheet 20 has a lower surface 20a (a surface on the lower metal sheet 10 side) overlaid on an upper surface 10a (a surface on the upper metal sheet 20 side) of the lower metal sheet 10. A device D, which is an object to be cooled, is attached to the lower surface 10b of the lower metal sheet 10 (in particular, the lower surface of the evaporator 11, which will be described later).

A sealed space 3 in which a working fluid 2 is sealed is formed between the lower metal sheet 10 and the upper metal sheet 20. Examples of the working fluid 2 include pure water, ethanol, methanol, acetone, and the like.

The lower metal sheet 10 and the upper metal sheet 20 are joined by diffusion bonding, which will be described later. In the embodiments shown in FIGS. 1 and 2, an example is shown in which the lower metal sheet 10 and the upper metal sheet 20 are both formed into a rectangular shape in plan view, but the invention is not limited to this. Here, the plane view refers to a direction perpendicular to the surface of the vapor chamber 1 that receives heat from the device D (the lower surface 10b of the lower metal sheet 10) and the surface that releases the received heat (the upper surface 20b of the upper metal sheet 20). This corresponds to, for example, a state in which the vapor chamber 1 is seen from above (see FIG. 1) or a state in which it is seen from below.

Note that when the vapor chamber 1 is installed in a mobile terminal, the vertical relationship between the lower metal sheet 10 and the upper metal sheet 20 may be disrupted depending on the posture of the mobile terminal. However, in this embodiment, the metal sheet that receives heat from device D is referred to as the lower metal sheet 10, the metal sheet that emits the received heat is referred to as the upper metal sheet 20, and the lower metal sheet 10 is referred to as the lower metal sheet 10. The explanation will be made with the upper metal sheet 20 disposed on the upper side.

As shown in FIG. 3, the lower metal sheet 10 includes an evaporation section 11 in which the working fluid 2 evaporates to generate steam, and a lower steam flow path provided on the upper surface 10a and formed in a rectangular shape in plan view. It has a recess 12 (first steam flow path recess). Among these, the lower vapor flow path concave portion 12 constitutes a part of the above-mentioned sealed space 3, and is configured mainly through which the vapor generated in the evaporation section 11 passes.

The evaporator 11 is arranged within the lower vapor flow path recess 12, and the vapor in the lower vapor flow path recess 12 is diffused in the direction away from the evaporator 11, and most of the vapor is relatively small. Transported to the cooler periphery. The evaporation section 11 is a section where the working fluid 2 in 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 section 11 is not limited to a portion that overlaps the device D, but is used as a concept that includes a portion where the working fluid 2 can be evaporated even if it does not overlap the device D. Here, the evaporator 11 can be provided at any location on the lower metal sheet 10, but in FIGS. 1 and 3, an example is shown in which it is provided in the center of the lower metal sheet 10. . In this case, the attitude of the mobile terminal in which the vapor chamber 1 is installed can be suppressed from affecting the stabilization of the operation of the vapor chamber 1.

In this embodiment, as shown in FIG. 2 and FIG. A plurality of lower flow path wall portions 13 (first flow path wall portions) are provided that protrude in a direction perpendicular to . In the present embodiment, an example is shown in which the lower flow path wall portion 13 extends in an elongated shape along the longitudinal direction of the vapor chamber 1 (the left-right direction in FIG. 3), and the upper flow path wall portion 13 described later It includes an upper surface 13a (first contact surface, protruding end surface) that contacts the lower surface 22a of the wall portion 22. Further, the lower flow path wall portions 13 are arranged parallel to each other and spaced apart from each other at equal intervals. In this way, the vapor of the working fluid 2 flows around each lower flow path wall portion 13 and is configured to be transported to the peripheral edge of the lower steam flow path recess 12. This prevents flow from being obstructed. Further, the lower channel wall portion 13 is arranged so as to overlap the corresponding upper channel wall portion 22 (described later) of the upper metal sheet 20 in plan view, and is designed to improve the mechanical strength of the vapor chamber 1. ing. The width w0 of the lower flow path wall portion 13 is, for example, 100 μm to 1500 μm, and the distance d between adjacent lower flow path wall portions 13 is preferably 100 μm to 2000 μm. Here, the width w0 means the dimension of the lower channel wall 13 in the direction perpendicular to the longitudinal direction of the lower channel wall 13, and for example, the width w0 is the dimension in the vertical direction in FIGS. 3 and 5. Equivalent to. Further, the height of the lower flow path wall portion 13 (in other words, the depth of the lower steam flow path recess 12) h0 (see FIG. 2) is preferably 100 μm to 300 μm.

As shown in FIGS. 2 and 3, a lower peripheral wall 14 is provided at the peripheral edge of the lower metal sheet 10. As shown in FIGS. The lower peripheral wall 14 is formed to surround the sealed space 3 , particularly the lower steam passage recess 12 , and defines the sealed space 3 . Furthermore, lower alignment holes 15 for positioning the lower metal sheet 10 and the upper metal sheet 20 are provided at each of the four corners of the lower peripheral wall 14 in a plan view.

In this embodiment, the upper metal sheet 20 has substantially the same structure as the lower metal sheet 10, except that a lower liquid flow path recess 30, which will be described later, is not provided. Below, the structure of the upper metal sheet 20 will be explained in more detail.

As shown in FIGS. 2 and 4, the upper metal sheet 20 has an upper steam passage recess 21 (second steam passage recess) provided on the lower surface 20a. This upper steam flow path recess 21 constitutes a part of the sealed space 3, and is mainly configured to allow steam generated in the evaporator 11 to pass therethrough and cool the steam. More specifically, the vapor in the upper vapor flow path recess 21 is diffused in a direction away from the evaporator 11, and most of the vapor is transported to the peripheral portion where the temperature is relatively low. Further, as shown in FIG. 2, on the upper surface 20b of the upper metal sheet 20, a housing member H that constitutes a part of a housing of a mobile terminal or the like is arranged. As a result, the steam in the upper steam flow path recess 21 is cooled by the outside air via the upper metal sheet 20 and the housing member H.

In this embodiment, as shown in FIG. 1 and FIG. In this case, a plurality of upper flow passage walls 22 (second flow passage walls) protruding downward (in a direction perpendicular to the ceiling surface 21a) from the bottom surface of the upper steam flow passage recess 21 is provided. . In the present embodiment, an example is shown in which the upper flow path wall portion 22 extends in an elongated shape along the longitudinal direction of the vapor chamber 1 (the left-right direction in FIG. 4), and the upper flow path wall portion 22 is It includes a lower surface 22a (second contact surface, protruding end surface) that contacts the upper surface 13a of the portion 13. Further, the upper channel wall portions 22 are arranged parallel to each other and spaced apart from each other at equal intervals. In this way, the vapor of the working fluid 2 flows around each upper flow path wall portion 22 and is configured to be transported to the peripheral edge of the upper steam flow path recess 21, so that the flow of steam is I'm restraining myself from being hindered. Further, the upper channel wall portion 22 is arranged so as to overlap the corresponding lower channel wall portion 13 of the lower metal sheet 10 in a plan view, thereby improving the mechanical strength of the vapor chamber 1. . Note that the width and height of the upper channel wall portion 22 are preferably the same as the width w0 and height h0 of the lower channel wall portion 13 described above.

As shown in FIGS. 2 and 4, an upper peripheral wall 23 is provided at the peripheral edge of the upper metal sheet 20. As shown in FIGS. The upper peripheral wall 23 is formed to surround the sealed space 3 , particularly the upper steam passage recess 21 , and defines the sealed space 3 . Furthermore, upper alignment holes 24 for positioning the lower metal sheet 10 and the upper metal sheet 20 are provided at each of the four corners of the upper peripheral wall 23 in a plan view. That is, each upper alignment hole 24 is arranged so as to overlap each of the lower alignment holes 15 described above during temporary fixing, which will be described later, and is configured to enable positioning of the lower metal sheet 10 and the upper metal sheet 20. .

Such lower metal sheet 10 and upper metal sheet 20 are permanently joined to each other, preferably by diffusion bonding. More specifically, as shown in FIG. 2, 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 contact each other, 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 channel wall portion 13 of the lower metal sheet 10 and the lower surface 22a of the upper channel wall portion 22 of the upper metal sheet 20 are in contact with each other, and correspond to each lower channel wall portion 13. The upper channel wall portions 22 are joined to each other. This improves the mechanical strength of the vapor chamber 1. In particular, since the lower flow path wall portion 13 and the upper flow path wall portion 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 other methods such as brazing, instead of diffusion bonding, as long as they can be permanently joined.

Further, as shown in FIG. 1, the vapor chamber 1 further includes an injection part 4 for injecting the working fluid 2 into the sealed space 3 at one end of the pair of longitudinal ends. The injection section 4 has a lower injection projection 16 that projects from the end surface of the lower metal sheet 10 and an upper injection projection 25 that projects from the end surface of the upper metal sheet 20. A lower injection channel recess 17 is formed on the upper surface of the lower injection protrusion 16, and an upper injection channel recess 26 is formed on the lower surface of the upper injection protrusion 25. The lower injection channel recess 17 communicates with the lower steam flow channel recess 12 , and the upper injection channel recess 26 communicates with the upper steam flow channel recess 21 . The lower injection channel recess 17 and the upper injection channel recess 26 form an injection channel for the working fluid 2 when the lower metal sheet 10 and the upper metal sheet 20 are joined. The working fluid 2 is injected into the sealed space 3 through the injection channel. In addition, in this embodiment, an example is shown in which the injection part 4 is provided at one end of a pair of longitudinal ends of the vapor chamber 1, but the invention is not limited to this. do not have.

Next, the lower liquid flow path recess 30 of the lower metal sheet 10 will be described in more detail using FIGS. 3, 5, and 6.

As shown in FIGS. 3 and 5, a lower liquid flow path recess 30 (first liquid flow path recess) through which the liquid working fluid 2 passes is provided on the upper surface 13a of each lower flow path wall portion 13. . More specifically, the lower liquid flow path recess 30 is formed on the upper surface 13a of the lower flow path wall portion 13. The lower liquid flow path recess 30 constitutes a part of the sealed space 3 described above, and communicates with the lower steam flow path recess 12 and the upper steam flow path recess 21 described above. The lower liquid flow path recess 30 is mainly configured to transport the working fluid 2 condensed from the vapor generated in the evaporator 11 to the evaporator 11. In the present embodiment, an example is shown in which the lower liquid flow path recess 30 extends in an elongated shape along the longitudinal direction of the lower flow path wall portion 13 (the left-right direction in FIG. 3), and It extends from one end to the other end in the longitudinal direction of the side channel wall portion 13 . In this way, the liquid working fluid 2 condensed at the peripheral edge of the lower steam flow path recess 12 and the upper steam flow path recess 21 is transported to the evaporation section 11 by capillary action. A plurality of lower liquid flow path recesses 30 are formed in the upper surface 13a of one lower flow path wall portion 13, and each lower liquid flow path recess 30 is spaced apart at equal intervals and parallel to each other. It is located.

Although not shown, each of the lower liquid flow path recesses 30 also communicates with the lower vapor flow path recess 12 in the evaporation section 11 . For example, a liquid flow path recess extending in a direction across the lower liquid flow path recess 30 (in the vertical direction in FIGS. 3 and 5) is provided, and this liquid flow path recess is connected to each lower liquid flow path recess 30 and below. It may also be configured to communicate with the side steam flow path recess 12 . Alternatively, in the evaporator 11, the lower surface 22a of the upper channel wall 22 is separated from the upper surface 13a of the lower channel wall 13, and the space between the upper surface 13a and the lower surface 22a is used for the lower vapor flow. It may be made to communicate with the passage recess 12 and the upper steam flow passage recess 21.

As shown in FIG. 6, the lower liquid channel recess 30 is formed on the upper surface 13a of the lower channel wall 13 and opens upward. That is, the lower liquid flow path recess 30 includes a lower recess opening 31 (a first recess opening) and a lower liquid flow path recess 30 located closer to the bottom of the lower liquid flow path recess 30 than the lower recess opening 31. It has a wide part 32 (first wide part). The lower recess opening 31 is an opening in the lower liquid flow path recess 30 at a position corresponding to the upper surface 13 a of the lower flow path wall 13 . The lower wide portion 32 is located closer to the bottom in FIG. 6 than the lower recess opening 31.

The lower liquid flow path recess 30 is formed so as to bulge (in a reverse tapered shape) from the lower recess opening 31 toward the bottom side of the lower liquid flow path recess 30 . More specifically, the width gradually increases from the lower recess opening 31 toward the bottom, and the width of the lower liquid flow path recess 30 becomes maximum at the lower wide portion 32. The width gradually decreases from the lower wide portion 32 toward the bottom side. In this manner, in the present embodiment, the width w2 of the lower wide portion 32 is larger than the width w1 of the lower recess opening 31 in the cross section of the lower liquid flow path recess 30. Note that the cross section means a cross section perpendicular to the longitudinal direction of the lower liquid flow path recess 30.

As shown in FIG. 6, the cross section of the lower liquid flow path recess 30 is preferably formed in an arc shape. Here, the cross section of the lower liquid flow path recess 30 is formed in a C-shape. The cross-sectional shape of the lower liquid flow path recess 30 can also be said to be an octopus pot shape.

The widths w1 and w2 of the lower liquid flow path recessed portion 30 are smaller than the width w0 of the lower flow path wall portion 13. As a result, the lower liquid flow path recess 30 is filled with the liquid working fluid 2 condensed from the vapor of the working fluid 2, and the filled liquid working fluid 2 is transported to the evaporation section 11 by capillary action. Ru. On the other hand, since the lower vapor flow path recess 12 and the upper vapor flow path recess 21 have a flow path cross-sectional area larger than the flow path cross-sectional area of the lower liquid flow path recess 30, they are mainly used in the evaporation section 11. The generated vapor of the working fluid 2 passes through.

The widths w1 and w2 of the lower liquid flow path recess 30 refer to the dimensions of the lower liquid flow path recess 30 in the direction orthogonal to the longitudinal direction of the lower liquid flow path recess 30, for example, the upper and lower widths in FIG. This corresponds to the dimension in the direction or the dimension in the left-right direction in FIG. The width w1 is preferably 10 μm to 100 μm, and the width w2 is preferably 20 μm to 150 μm. The width w1 and the width w2 can be adjusted by controlling the spray pressure of the etching liquid when forming the lower liquid flow path recess 30 by half etching as described later. Further, the depth h1 of the lower liquid flow path recess 30 is preferably 20 μm to 150 μm, although it depends on the width w1 and the width w2.

Such a lower liquid flow path recess 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 this embodiment, an upper liquid flow path recess 35 (see FIG. 16), which will be described later, is not formed on the lower surface 22a of the upper flow path wall portion 22 of the upper metal sheet 20. That is, the lower surface 22 a is formed in a flat shape and exposed to the lower liquid flow path recess 30 . In this way, in the cross section of the lower liquid flow path recess 30, the entire lower liquid flow path recess 30 is covered with the flat lower surface 22a of the upper flow path wall 22.

By the way, the materials used for the lower metal sheet 10 and the upper metal sheet 20 are not particularly limited as long as they have good thermal conductivity, but for example, the lower metal sheet 10 and the upper metal sheet 20 are made of copper. Alternatively, it is preferably made of a copper alloy. Thereby, the thermal conductivity of the lower metal sheet 10 and the upper metal sheet 20 can be increased. Therefore, the heat transport efficiency of the vapor chamber 1 can be improved. Further, the thickness of the vapor chamber 1 is 0.1 mm to 1.0 mm. Although the case is shown in which the thickness T1 of the lower metal sheet 10 and the thickness T2 of the upper metal sheet 20 are equal, the case is not limited to this, and the thickness T1 of the lower metal sheet 10 and the thickness T2 of the upper metal sheet 20 are equal. The thicknesses T2 do not have to be equal.

Next, the operation of this embodiment having such a configuration will be explained. Here, first, a method for manufacturing the vapor chamber 1 will be explained using FIGS. 7 to 15, but the explanation of the half-etching process of the upper metal sheet 20 will be simplified. 7, FIG. 8, and FIGS. 13 to 15 show cross sections similar to the cross section in FIG. 2, and FIGS. 9 to 12 show cross sections similar to the cross section in FIG. 6.

First, as shown in FIG. 7, a flat metal material sheet M is prepared.

Subsequently, as shown in FIG. 8, the metal material sheet M is half-etched to form a lower vapor flow path recess 12 and a lower liquid flow path recess 30 that constitute a part of the sealed space 3.

In this case, first, as shown in FIG. 9, a resist film 40 is formed on the upper surface Ma of the metal material sheet M. For the resist film 40, an electrodeposited resist material that can be deposited by an electric field can be suitably used, but if the resist film 40 can be formed on the metal material sheet M, other materials such as a liquid resist material can be used. It's okay.

Subsequently, as shown in FIG. 10, the resist film 40 is patterned. That is, the resist film 40 is formed in a pattern corresponding to the lower vapor flow path recess 12 and the plurality of lower liquid flow path recesses 30 by photolithography, and resist openings corresponding to the lower vapor flow path recess 12 are formed. 42a and a resist opening 42b corresponding to the lower liquid flow path recess 30 are formed.

Subsequently, as shown in FIG. 11, in a half-etching step, the upper surface Ma of the metal material sheet M is half-etched. As a result, the portions of the upper surface Ma corresponding to the resist openings 42a and 42b of the resist film 40 are half-etched, and the lower vapor flow path recess 12, the lower flow path wall 13, and the lower peripheral wall 14 are half-etched. It is formed. At this time, a lower liquid flow path recess 30 is formed on the upper surface 13a of the lower flow path wall portion 13. Further, the lower injection channel recess 17 shown in FIGS. 1 and 3 is also formed at the same time, and the metal material sheet M is etched from the upper surface Ma and the lower surface so as to have the outer contour shape as shown in FIG. A predetermined outer contour shape is obtained. Note that half etching means etching for forming a recess that does not penetrate the material. Therefore, the depth of the recess formed by half etching is not limited to half the thickness of the lower metal sheet 10. As the etching solution, for example, an iron chloride-based etching solution such as a ferric chloride aqueous solution, or a copper chloride-based etching solution such as a copper chloride aqueous solution can be used.

The half etching here is preferably spray etching in which an etching solution is sprayed onto the upper surface Ma of the metal material sheet M. In the case of spray etching, by spray etching the upper surface Ma of the metal material sheet M at a pressure of, for example, 1 kg/cm ² or more, the lower liquid flow path recess 30 shown in FIG. 6 where the width w1 is larger than the width w2 is formed. can be formed. Note that the cross-sectional shape of the lower vapor flow path recess 12 formed together with the lower liquid flow path recess 30 is also formed in the same octopus shape (arc shape or C-shape) as the lower liquid flow path recess 30. It's okay. That is, the lower steam flow path recess 12 may be formed so as to swell from the opening toward the bottom side (in a reverse tapered shape). In this case, the flow path cross-sectional area of the lower steam flow path recess 12 can be increased to reduce the flow path resistance of the vapor of the working fluid 2.

Here, in the etching of the lower liquid flow path recess 30, although it is influenced by the opening area of the lower recess opening 31 and the thickness of the resist film 40, in general, copper etching is performed using a ferric chloride aqueous solution. Since etching is diffusion-controlled, the portion to which fresh ferric chloride aqueous solution is supplied before reaction tends to be easily etched. On the other hand, the ferric chloride aqueous solution consumed in the etching reaction deteriorates in etching ability. Therefore, when performing spray etching at high pressure using a ferric chloride aqueous solution, unreacted fresh ferric chloride aqueous solution flows from the lower recess opening 31 of the lower liquid flow path recess 30 into the lower liquid flow path recess 30. Since the liquid is supplied toward the bottom of the channel recess 30, the bottom of the lower liquid channel recess 30 and the inner wall near the bottom are likely to be etched. On the other hand, in the vicinity of the lower recess opening 31 of the lower liquid flow path recess 30, the reacted ferric chloride aqueous solution with deteriorated etching ability tends to remain. The inner wall near the recess opening 31 is difficult to be etched. By performing spray etching with increased pressure in this manner, the lower liquid flow path recess 30 according to the present embodiment can be obtained.

Thereafter, as shown in FIG. 12, the resist film 40 is removed. In this way, as shown in FIG. 8, the lower metal sheet 10 in which the lower vapor flow path recess 12, the lower flow path wall 13, the lower peripheral wall 14, and the lower liquid flow path recess 30 are formed. is obtained. In this way, by forming the lower vapor flow path recess 12, the lower flow path wall 13, the lower peripheral wall 14, and the lower liquid flow path recess 30 in one half etching process, the half etching process It is possible to reduce the number of times, and the manufacturing cost of the vapor chamber 1 can be reduced. However, the present invention is not limited to this, and the lower vapor flow path recess 12, the lower flow path wall 13, and the lower peripheral wall 14 are formed in the first half etching step, and then the second half etching step is performed. As an etching process, the lower liquid flow path recess 30 may be formed on the upper surface 13a of the lower flow path wall portion 13. In this case, the depth h0 of the lower vapor flow path recess 12 and the depth h1 of the lower liquid flow path recess 30 can be easily made different.

On the other hand, 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 the upper vapor passage recess 21, the upper passage wall 22, and the upper peripheral wall 23. In this way, the upper metal sheet 20 described above is obtained.

Next, as shown in FIG. 13, the lower metal sheet 10 having the lower steam passage recess 12 and the upper metal sheet 20 having the upper steam passage recess 21 are temporarily attached. In this case, first, by using the lower alignment hole 15 (see FIGS. 1 and 3) of the lower metal sheet 10 and the upper alignment hole 24 (see FIGS. 1 and 4) of the upper metal sheet 20, The metal sheet 10 and the upper metal sheet 20 are positioned. Subsequently, the lower metal sheet 10 and the upper metal sheet 20 are fixed. The fixing method is not particularly limited, but for example, the lower metal sheet 10 and the upper metal sheet 20 may be fixed by resistance welding to the lower metal sheet 10 and the upper metal sheet 20. It's okay. In this case, as shown in FIG. 13, it is preferable to perform spot resistance welding using an electrode rod 43. Laser welding may be used instead of resistance welding. Alternatively, the lower metal sheet 10 and the upper metal sheet 20 may be ultrasonically bonded and fixed by irradiating ultrasonic waves. Furthermore, although an adhesive may be used, it is preferable to use an adhesive that does not have an organic component or has a small amount of organic component. In this way, the lower metal sheet 10 and the upper metal sheet 20 are fixed in a positioned state.

After the temporary fixing, as shown in FIG. 14, the lower metal sheet 10 and the upper metal sheet 20 are permanently joined by diffusion bonding. Diffusion bonding refers to bonding the lower metal sheet 10 and the upper metal sheet 20 to be bonded, and applying pressure in a controlled atmosphere such as a vacuum or inert gas in a direction to bring the metal sheets 10 and 20 into close contact. This is a method of bonding using the diffusion of atoms that occurs at the bonding surface. Diffusion bonding heats the materials of the lower metal sheet 10 and the upper metal sheet 20 to a temperature close to but below the melting point, thereby avoiding melting and deformation of each metal sheet 10, 20. 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 serve as bonding surfaces and are diffusion bonded. As a result, 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 . In addition, an injection flow path for the hydraulic fluid 2 that communicates with the sealed space 3 is formed by the lower injection flow path recess 17 (see FIGS. 1 and 3) and the upper injection flow path recess 26 (see FIGS. 1 and 4). be done. Furthermore, the upper surface 13a of the lower flow path wall 13 of the lower metal sheet 10 and the lower surface 22a of the upper flow path wall 22 of the upper metal sheet 20 serve as a bonding surface and are diffusion bonded, so that the vapor chamber 1 is Mechanical strength is improved. The lower liquid flow path recess 30 formed in the upper surface 13a of the lower flow path wall portion 13 remains as a flow path for the liquid working fluid 2.

After permanent bonding, as shown in FIG. 15, the working fluid 2 is injected into the sealed space 3 from the injection part 4 (see FIG. 1). At this time, first, the sealed space 3 is evacuated to reduce the pressure, and then the hydraulic fluid 2 is injected into the sealed space 3. During injection, the working fluid 2 passes through the injection channel formed by the lower injection channel recess 17 and the upper injection channel recess 26 .

After injection of the working fluid 2, the injection channel described above is sealed. For example, it is preferable to irradiate the injection part 4 with a laser to partially melt the injection part 4 and seal the injection channel. As a result, communication between the sealed space 3 and the outside air is cut off, and the hydraulic fluid 2 is sealed in the sealed space 3. In this way, the hydraulic fluid 2 in the sealed space 3 is prevented from leaking to the outside.

In the manner described above, the vapor chamber 1 according to this embodiment is obtained.

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

The vapor chamber 1 obtained as described above is installed in a housing of a mobile terminal or the like, 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 inside the sealed space 3 is caused by its surface tension to form on the wall surface of the sealed space 3, that is, in the lower steam passage recess 12. It adheres to the wall surface and the wall surface of the upper steam flow path recess 21.

When the device D generates heat in this state, the working fluid 2 present in the evaporation section 11 of the lower vapor flow path recess 12 receives heat from the device D. The received heat is absorbed as latent heat, the working fluid 2 evaporates (vaporizes), and vapor of the working fluid 2 is generated. Most of the generated steam diffuses into the lower steam flow path recess 12 and the upper steam flow path recess 21 that constitute the sealed space 3 (see solid line arrows in FIG. 3 and solid line arrows in FIG. 4). The steam in the upper steam flow path recess 21 and the lower steam flow path recess 12 leaves the evaporation section 11, and most of the steam is transported to the peripheral portion where the temperature is relatively low. The steam diffused to the periphery radiates heat and is cooled at the periphery. The heat received by the lower metal sheet 10 and the upper metal sheet 20 from the steam at the periphery is transferred to the outside air via the housing member H (see FIG. 2).

By radiating heat to the peripheral portion, the steam loses the latent heat absorbed in the evaporation section 11 and condenses. Most of the liquid working fluid 2 adheres to the wall surface of the lower vapor flow path recess 12 or the wall surface of the upper steam flow path recess 21 and reaches the lower liquid flow path recess 30 . Here, since the working fluid 2 continues to evaporate in the evaporation section 11, the working fluid 2 in the portion of the lower liquid flow path concave section 30 other than the evaporation section 11 is transported toward the evaporation section 11 by capillary action. (See the dashed arrow in Figure 3). As a result, the liquid working fluid 2 adhering to the wall surface of the lower steam flow path recess 12 and the wall surface of the upper steam flow path recess 21 can be removed from the lower steam flow path recess 30 or the upper steam flow path recess 12 or the upper steam flow path recess 30 . It moves toward both ends in the longitudinal direction of the lower liquid flow path recess 30 that is open toward the flow path recess 21 and enters into the lower liquid flow path recess 30 from the both ends. As a result, the lower liquid flow path recess 30 is filled with the liquid working fluid 2, and the filled working fluid 2 exerts a propulsive force toward the evaporator 11 due to the capillary action of the lower liquid flow path recess 30. and is smoothly transported toward the evaporation section 11.

In this embodiment, the width w2 of the lower wide portion 32 of the lower liquid flow path recess 30 is larger than the width w1 of the lower recess opening 31. That is, as shown in FIG. 6, since the lower liquid flow path recess 30 is formed to swell from the lower recess opening 31 toward the bottom side, in the cross section of the lower liquid flow path recess 30, , the length of the outline of the lower liquid flow path recess 30 can be increased. For example, the lower liquid flow path recess 30 according to this embodiment can have a longer contour line than the forward tapered liquid flow path recess 50 shown in FIG. In this case, the area of the wall surface of the lower liquid flow path recess 30 can be increased, and the area of contact between the wall surface of the lower liquid flow path recess 30 and the liquid working fluid 2 can be increased. Therefore, the capillary action exerted on the liquid working fluid 2 passing through the lower liquid flow path recess 30 can be increased, and the working fluid 2 can be smoothly transported toward the evaporation section 11.

Further, as described above, since the lower liquid flow path recess 30 is formed to swell from the lower recess opening 31 toward the bottom side, the cross-sectional shape of the lower liquid flow path recess 30 is It can be made close to a perfect circular shape. For example, the lower liquid flow path recess 30 according to this embodiment can have a cross-sectional shape closer to a perfect circle than the forward tapered liquid flow path recess 50 shown in FIG. In this case, the flow path resistance experienced by the liquid working fluid 2 passing through the lower liquid flow path recess 30 can be reduced, and the working fluid 2 can be smoothly transported toward the evaporation section 11.

The working fluid 2 that has reached the evaporator 11 receives heat from the device D again and evaporates. In this way, the working fluid 2 circulates within the vapor chamber 1 while repeating phase changes, that is, evaporation and condensation, thereby transferring and discharging the heat of the device D. As a result, device D is cooled.

As described above, according to the present embodiment, the lower liquid flow path recess 30 through which the working fluid 2 passes is provided on the upper surface 13a of the lower flow path wall portion 13 of the lower metal sheet 10, and the lower liquid flow path In the cross section of the channel recess 30, the width w2 of the lower wide part 32 of the lower liquid flow channel recess 30 is larger than the width w1 of the lower recess opening 31. As a result, in the cross section of the lower liquid flow path recess 30, the length of the outline of the lower liquid flow path recess 30 can be increased, and the capillary action can be increased. Moreover, the cross-sectional shape of the lower liquid flow path recessed portion 30 can be approximated to a perfect circular shape, and the flow path resistance can be reduced. Therefore, in the lower liquid flow path concave portion 30, the flow path resistance of the liquid working fluid 2 can be reduced and the capillary action can be enhanced. As a result, the liquid working fluid 2 can be smoothly transported toward the evaporation section 11, promoting heat transfer in the device D, and improving heat transport efficiency.

Further, according to the present embodiment, the cross section of the lower liquid flow path recess 30 is formed in an arc shape. As a result, the cross-sectional shape of the lower liquid flow path recess 30 can be made closer to a perfect circular shape, and the flow path resistance can be further reduced.

In addition, in the first embodiment described above, an example has been described in which the upper metal sheet 20 has the upper steam flow path recess 21, but the upper metal sheet 20 is not limited to this. , it is not necessary to have a flat plate shape as a whole and not have the upper steam flow path recess 21. In this case, the mechanical strength of the vapor chamber 1 can be improved.

Note that the vapor chamber 1 according to the first embodiment described above can be modified in various ways.

(Modification 1)
In the present embodiment described above, an example has been described in which the liquid flow path recess is not provided on the lower surface 22a of the upper flow path wall portion 22 of the upper metal sheet 20. However, it is not limited to this. For example, as shown in FIG. 16, an upper liquid passage recess 35 (second liquid passage recess) through which the liquid working fluid 2 passes may be provided on the lower surface 22a of each upper passage wall 22. In FIG. 16 , an example is shown in which the upper liquid flow path recess 35 has the same shape as the lower liquid flow path recess 30 . That is, the upper liquid flow path recess 35 communicates with the upper vapor flow path recess 21 and has a width smaller than the width of the upper flow path wall 22 . The upper liquid flow path recess 35 is located closer to the upper recess opening 36 (second recess opening) and the upper liquid flow path recess 35 is located closer to the bottom of the upper liquid flow path recess 35 (upper side in FIG. 16) than the upper recess opening 36. part 37 (second wide part). In the cross section of the upper liquid flow path recess 35, the width w4 of the upper wide portion 37 is larger than the width w3 of the upper recess opening 36.

In particular, in Modification 1 shown in FIG. 16, the lower liquid flow path recess 30 and the upper liquid flow path recess 35 face each other. That is, the two liquid flow path recesses 30 and 35 facing each other communicate with each other to form one flow path. In this case, since the cross-sectional area of the flow path increases, the flow path resistance of the liquid working fluid 2 toward the evaporator 11 can be reduced. In addition, when the lower liquid flow path recess 30 and the upper liquid flow path recess 35 face each other, the cross-sectional shape of the flow path defined by these two liquid flow path recesses 30 and 35 is changed to a perfect circular shape. The flow path resistance can be further reduced. Note that in order to make the cross-sectional shape of the flow path close to a perfect circular shape, in the modified example shown in FIG. 36 have the same width, and the lower liquid flow path recess 30 and the upper liquid flow path recess 35 are arranged so that both recess openings 31 and 36 overlap.

Note that the lower liquid flow path recess 30 and the upper liquid flow path recess 35 do not need to be disposed offset in the left-right direction in FIG. 16 and do not communicate with each other. Even in this case, since the liquid working fluid 2 can pass through the upper liquid flow path recess 35, the total flow path cross-sectional area of the liquid working fluid 2 toward the evaporation section 11 is increased in the vapor chamber 1 as a whole. Therefore, the flow path resistance of the liquid working fluid 2 toward the evaporator 11 can be reduced.

(Modification 2)
Further, as shown in FIG. 17, the lower surface 22a of the upper flow path wall 22 has an upper liquid flow path having a cross-sectional shape different from that of the lower liquid flow path recess 30 and the upper liquid flow path recess 35 shown in FIG. A path recess 55 may be provided. For example, as shown in FIG. 17, the upper liquid flow path recess 55 has an upper recess opening 56, but does not have portions corresponding to the wide portions 32 and 37 shown in FIGS. 6 and 16. First, in the cross section of the upper liquid flow path recess 55, the width of the upper liquid flow path recess 55 gradually decreases from the upper recess opening 56 toward the bottom side (upper side in FIG. 17) of the upper liquid flow path recess 55. It may be. In this case, the width of the upper liquid flow path recess 55 is maximum at the upper recess opening 56, and the cross section of the upper liquid flow path recess 55 is formed in a forward tapered shape. In this case, the cross-sectional shape of the flow path defined by the two liquid flow path recesses 30 and 55 can be approximated to a perfect circular shape, and the flow path resistance can be further reduced. In particular, in Modification 2 shown in FIG. 17, the cross section of the upper liquid flow path recess 55 is formed in a flat arc shape. In this case as well, the cross-sectional shape of the flow path defined by the two liquid flow path recesses 30 and 53 facing each other can be made closer to a perfect circular shape, and the flow path resistance can be further reduced.

(Second embodiment)
Next, a vapor chamber and a vapor chamber metal sheet according to a second embodiment of the present invention will be described using FIGS. 18 to 23.

In the second embodiment shown in FIGS. 18 to 23, the liquid flow path recess provided on the upper surface of the lower metal sheet and the liquid flow path recess provided on the lower surface of the upper metal sheet face each other, and the upper surface The main difference is that a part of the bottom surface is exposed to the liquid flow path recess provided in the bottom surface, or a part of the top surface is exposed to the liquid flow path recess provided in the bottom surface. , is substantially the same as the first embodiment shown in FIGS. 1 to 17. Note that in FIGS. 18 to 23, the same parts as those in the first embodiment shown in FIGS. 1 to 17 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, as shown in FIG. 18, a lower liquid passage recess 50 (first liquid A channel recess) is provided. On the other hand, the lower surface 22a of the upper flow path wall portion 22 of the upper metal sheet 20 is also provided with an upper liquid flow path recess 55 (second liquid flow path recess) through which the liquid working fluid 2 passes. Each of the liquid flow path recesses 50 and 55 constitutes a part of the sealed space 3, but the lower liquid flow path recess 30 shown in FIG. 6 and the upper liquid flow path recess 35 shown in FIG. They have different cross-sectional shapes.

That is, in the form shown in FIG. 18, the lower liquid flow path recess 50 has a lower recess opening 51 (first recess opening), which corresponds to the lower wide part 32 shown in FIG. It does not have any parts. In the cross section of the lower liquid flow path recess 50, the width of the lower liquid flow path recess 50 increases from the lower recess opening 51 toward the bottom side of the lower liquid flow path recess 50 (lower side in FIG. 18). It is gradually getting smaller. In this case, the width of the lower liquid flow path recess 50 is maximum at the lower recess opening 51, and the cross section of the lower liquid flow path recess 50 is formed in a forward tapered shape and an arc shape. There is. Here, an example is shown in which the cross section of the lower liquid flow path recess 50 is formed in a semicircular shape.

In FIG. 18, an example is shown in which the upper liquid flow path recess 55 has the same shape as the lower liquid flow path recess 50. That is, the upper liquid flow path recess 55 has an upper recess opening 56 (second recess opening), but does not have a portion corresponding to the upper wide portion 37 shown in FIG. 16. In the cross section of the upper liquid flow path recess 55, the width of the upper liquid flow path recess 55 gradually decreases from the upper recess opening 56 toward the bottom side (upper side in FIG. 18) of the upper liquid flow path recess 55. There is. In this case, the width of the upper liquid flow path recess 55 is maximum at the upper recess opening 56, and the cross section of the upper liquid flow path recess 55 is formed in a forward tapered shape and an arc shape. Here, an example is shown in which the cross section of the upper liquid flow path recess 55 is formed in a semicircular shape. The lower recess opening 51 of the lower liquid flow path recess 50 and the recess opening 52 of the upper liquid flow path recess 55 have the same width.

The lower liquid flow path recess 50 provided on the upper surface 13a of the lower flow path wall 13 and the upper liquid flow path recess 55 provided on the lower surface 22a of the upper flow path wall 22 are opposed to each other. That is, the two liquid flow path recesses 50 and 55 facing each other communicate with each other to form one flow path. In this case, since the cross-sectional area of the flow path increases, the flow path resistance of the liquid working fluid 2 toward the evaporator 11 can be reduced.

Further, in this embodiment, a portion of the lower surface 22a of the upper flow path wall portion 22 is exposed in the lower liquid flow path recessed portion 50. Further, a portion of the upper surface 13a of the lower flow path wall portion 13 is exposed in the upper liquid flow path recessed portion 55. In other words, the lower liquid flow path recess 50 and the upper liquid flow path recess 55 are shifted from each other in the left-right direction in FIG. 18 . In this case, in the cross section, the length of the outline of one flow path formed by the two liquid flow path recesses 50 and 55 can be increased. Thereby, the capillary action exerted on the liquid working fluid 2 passing through the liquid flow path recesses 50 and 55 can be increased.

As described above, according to the present embodiment, the lower liquid flow path recess 50 provided in the upper surface 13a of the lower flow path wall portion 13 of the lower metal sheet 10 and the upper flow path wall portion of the upper metal sheet 20 The upper liquid flow path recesses 55 provided in the lower surface 22a of 22 face each other, and a portion of the lower surface 22a is exposed to the lower liquid flow path recess 50. As a result, in the cross section, the length of the outline of one flow path formed by the two liquid flow path recesses 50 and 55 can be increased, and the capillary action can be increased. Moreover, the cross-sectional area of the flow path can be increased, and the flow path resistance can be reduced. Therefore, in the liquid flow path recesses 50 and 55, the capillary action can be enhanced while reducing the flow path resistance of the liquid working fluid 2.

Further, according to the present embodiment, a part of the upper surface 13a of the lower channel wall portion 13 of the lower metal sheet 10 is exposed in the upper liquid channel recessed portion 55. As a result, the length of the contour line of one flow path formed by the two liquid flow path recesses 50 and 55 can be further increased in the cross section, and the capillary action can be further increased. .

Note that the vapor chamber 1 according to the second embodiment described above can be modified in various ways.

(Modification 3)
Furthermore, in the present embodiment described above, an example has been described in which the two liquid flow path recesses 50 and 55 facing each other are formed in a forward tapered shape. However, the present invention is not limited to this, and at least one of the two liquid flow path recesses 50 and 55 facing each other may be formed in a reverse tapered shape. For example, as shown in FIG. 19, the cross-sectional shape of the lower liquid flow path recess 50 is replaced with the reversely tapered cross-sectional shape of the lower liquid flow path recess 30 shown in FIG. The cross-sectional shape may be replaced with the cross-sectional shape of the reversely tapered upper liquid flow path recess 35 shown in FIG. In FIG. 19, the first liquid flow path recess provided on the upper surface 13a of the lower flow path wall 13 is indicated by the reference numeral 30, and the second liquid flow path recess provided on the lower surface 22a of the upper flow path wall 22 is shown. is indicated by reference numeral 35. In the third modification shown in FIG. 19, the length of the outline of one flow path formed by the two liquid flow path recesses 30 and 35 can be further increased in the cross section, and the capillary action can be further enhanced. can be increased.

(Modification 4)
In the above-mentioned modification 3, the upper liquid flow path recess 35 may be formed in a forward tapered flat arc shape as an upper liquid flow path recess 55 as shown in FIG. In this case as well, in the cross section, the length of the outline of one flow path formed by the two liquid flow path recesses 30 and 55 can be increased, and the capillary action can be increased.

(Modification 5)
In the present embodiment described above, the upper liquid flow path recess 50 provided in the upper surface 13a of the lower flow path wall 13 of the lower metal sheet 10 is provided with the upper flow path wall 22 of the upper metal sheet 20. An example has been described in which a portion of the lower surface 22a is exposed and a portion of the upper surface 13a is exposed to the upper liquid flow path recess 55 provided in the lower surface 22a. However, the present invention is not limited to this, and although not shown, the upper surface 13a may not be exposed in the upper liquid flow path recess 55, or as shown in FIG. The lower surface 22a does not need to be exposed. In Modification 5 shown in FIG. 21, the width of the lower recess opening 51 of the lower liquid flow path recess 50 is smaller than the width of the upper recess opening 56 of the upper liquid flow path recess 55. The radius of the lower liquid flow path recess 50 formed in a semicircular cross section is smaller than the radius of the upper liquid flow path recess 55 formed in a semicircle. The lower liquid flow path recess 50 and the upper liquid flow path recess 55 are arranged concentrically (so that their centers overlap in plan view). As a result, portions of the upper surface 13 a on both sides of the lower liquid flow path recess 50 are exposed to the upper liquid flow path recess 55 . Also in this case, in the cross section, the length of the outline of one flow path formed by the two liquid flow path recesses 50 and 55 can be increased, and the capillary action can be increased.

(Modification 6)
Furthermore, in the above-mentioned modification 5, an example has been described in which the two liquid flow path recesses 50 and 55 facing each other are formed in a forward tapered shape. However, the present invention is not limited to this, and at least one of the two liquid flow path recesses 50 and 55 facing each other may be formed in a reverse tapered shape. For example, as shown in FIG. 22, the cross-sectional shape of the lower liquid flow path recess 50 is replaced with the cross-sectional shape of the reversely tapered lower liquid flow path recess 30 shown in FIG. The cross-sectional shape may be replaced with the cross-sectional shape of the reversely tapered upper liquid flow path recess 35 shown in FIG. In FIG. 22, the first liquid flow path recess provided on the upper surface 13a of the lower flow path wall 13 is indicated by the reference numeral 30, and the second liquid flow path recess provided on the lower surface 22a of the upper flow path wall 22. is indicated by reference numeral 35. In modification 6 shown in FIG. 22, the width of the lower recess opening 31 of the lower liquid flow path recess 30 is smaller than the width of the upper recess opening 36 of the upper liquid flow path recess 35. As a result, portions of the upper surface 13 a on both sides of the lower liquid flow path recess 30 are exposed to the upper liquid flow path recess 35 . Therefore, in the cross section, the length of the outline of one flow path formed by the two liquid flow path recesses 30 and 35 can be increased, and the capillary action can be increased.

(Modification 7)
In the fifth modification described above, the upper liquid flow path recess 35 may be formed in a forward tapered flat arc shape as an upper liquid flow path recess 55 as shown in FIG. In this case as well, in the cross section, the length of the outline of one flow path formed by the two liquid flow path recesses 30 and 55 can be increased, and the capillary action can be increased.

The present invention is not limited to the above-described embodiments and modifications as they are, but can be implemented by modifying the constituent elements within the scope of the invention at the implementation stage. Moreover, various inventions can be formed by appropriately combining the plurality of components disclosed in the above embodiments and modified examples. Some components may be deleted from all the components shown in the embodiments and modifications. Furthermore, in each of the embodiments and modifications described above, the configuration of the lower metal sheet 10 and the configuration of the upper metal sheet 20 may be replaced.

1 Vapor chamber 2 Working fluid 3 Sealed space 10 Lower metal sheet 11 Evaporation section 12 Lower vapor flow path recess 12a Bottom surface 13 Lower flow path wall 13a Upper surface 20 Upper metal sheet 21 Upper vapor flow path recess 21a Ceiling surface 22 Upper side Channel wall portion 22a Lower surface 30 Lower liquid flow path recess 31 Lower recess opening 32 Lower wide portion 35 Upper liquid flow path recess 36 Upper recess opening 37 Upper wide portion 50 Lower liquid flow path recess 55 Upper liquid flow road recess

Claims (6)

A vapor chamber filled with hydraulic fluid,
a first metal sheet;
a second metal sheet provided on the first metal sheet,
A vapor flow path through which the vapor of the working fluid passes and a liquid flow path through which the liquid working fluid passes,
The liquid flow path is provided in a first liquid flow path recess provided on a surface of the first metal sheet on the side of the second metal sheet, and on a surface of the second metal sheet on the side of the first metal sheet. formed by the second liquid flow path recesses facing each other and communicating with each other,
The cross-sectional shape of the first liquid flow path recess and the cross-sectional shape of the second liquid flow path recess are different from each other,
The first liquid flow path recess includes a first recess opening, and the cross-sectional shape of the first liquid flow path recess extends from the first recess opening toward the bottom side of the first liquid flow path recess. It has an arc shape with a widening width.
The second liquid flow path recess includes a second recess opening, and the cross-sectional shape of the second liquid flow path recess extends from the second recess opening toward the bottom side of the second liquid flow path recess. A vapor chamber that is shaped like an arc that narrows in width. The vapor chamber according to claim 1, wherein the cross-sectional area of the first liquid flow path recess is larger than the cross-sectional area of the second liquid flow path recess. The vapor chamber according to claim 2, wherein the second liquid flow path recess has a cross-sectional shape of a flat arc. The vapor chamber according to any one of claims 1 to 3, wherein the first liquid flow path recess and the second liquid flow path recess are offset from each other in the width direction. The vapor chamber according to any one of claims 1 to 4, wherein the length in the width direction of the first recess opening and the length in the width direction of the second recess opening are different from each other. A mobile terminal comprising the vapor chamber according to any one of claims 1 to 5.

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