JP2019196875A - Vapor chamber and electronic device - Google Patents

Abstract

To provide a vapor chamber capable of obtaining high heat transport capacity even in a case of being made thin, and also capable of suppressing fracture of a wall part between flow passages.SOLUTION: A vapor chamber is configured such that a sealed space is formed between two sheets, and working fluid is sealed in the space. In the sealed space, a plurality of flow passages through which the working fluid flows is formed. Between adjacent flow passages, a wall is provided so as to connect two sheets. The wall width Sis 20 μm or more and 300 μm or less, and S/S, which is the relationship with the cross sectional area S(μm) of the cross section of the flow passage, is 0.005 (μm) or more and 0.04 (μm) or less.SELECTED DRAWING: Figure 14

Description

  The present invention relates to a vapor chamber that transports heat by recirculating a working fluid enclosed in a sealed space with a phase change.

The amount of heat generated from electronic components such as a CPU (central processing unit) provided in electronic devices typified by personal computers and mobile terminals such as mobile phones and tablet terminals tends to increase due to improvement in information processing capability. There is a technology to cool this.
A heat pipe is well known as a means for such cooling. In this method, the working fluid sealed in the pipe diffuses the heat in the heat source by transporting it to other parts, thereby cooling the heat source.

  On the other hand, in recent years, these electronic devices have been remarkably reduced in thickness, and cooling means thinner than conventional heat pipes has been required. On the other hand, for example, a vapor chamber as described in Patent Document 1 has been proposed.

  The vapor chamber is a device that develops the concept of heat transport by heat pipes into a flat member. That is, in the vapor chamber, the working fluid is sealed between the opposing flat plates, and the working fluid recirculates with a phase change to transport heat, and transport and diffuse the heat in the heat source to cool the heat source. To do.

More specifically, a flow path through which steam and / or condensate flows is provided between the opposing flat plates of the vapor chamber, and the working fluid is sealed therein. When the vapor chamber is disposed in the heat source, the working fluid receives the heat from the heat source and evaporates in the vicinity of the heat source, and moves as a gas (vapor) through the flow path. Thereby, the heat from the heat source is smoothly transported to a position away from the heat source, and as a result, the heat source is cooled.
The working fluid in a gaseous state that has transported heat from the heat source moves to a position away from the heat source, and is cooled and condensed by absorbing the heat to the surroundings, and changes into a liquid state. The phase-change working fluid in the liquid state passes through the flow path, returns to the position of the heat source, receives the heat from the heat source, evaporates, and changes to a gaseous state.
The heat generated from the heat source by the above circulation is transported to a position away from the heat source, and the heat source is cooled.

  Patent Document 1 discloses a vapor chamber (sheet type heat pipe) in which such flow paths (steam flow path and condensate flow path (wick)) are formed.

JP 2008-51407 A

An electronic device including such a vapor chamber is assumed to be used in various environments, and includes an environment below freezing point. In a vapor chamber using a working fluid, the working fluid may freeze in an environment below freezing. When the working fluid freezes, the volume increases, so that the frozen working fluid pushes in the direction to separate the two flat plates constituting the vapor chamber and applies force, so it is formed between adjacent flow paths and is formed between the two flat plates. There is a problem that the walls connecting the two are destroyed.
Such a fracture rarely occurs due to a single freezing of the working fluid, but plastic deformation accumulates due to repeated freezing and melting of the working fluid, resulting in a fracture due to a large wall fracture. The rupture causes leakage of the working fluid, which may cause a short circuit of surrounding electronic components and failure of the electronic device.

  In order to prevent such destruction, for example, a space serving as a buffer for volume expansion may be provided in a space in which a working fluid is enclosed. However, such a space is not preferable from the viewpoint of reducing the vapor chamber thickness and improving the performance (improvement of heat transport capability), but there is a possibility that this may be hindered.

  In view of the above problems, an object of the present invention is to provide a vapor chamber that can obtain a high heat transport capability even when it is thinned, and can suppress breakage of a wall between flow paths. In addition, an electronic device including the vapor chamber is provided.

One aspect of the present invention is a vapor chamber in which a sealed space is formed between two sheets, and the working fluid is sealed in the space, and a plurality of working fluid flows in the sealed space. A flow path is formed, and a wall is provided between two adjacent flow paths so as to connect two sheets. The wall width S _A is 20 μm or more and 300 μm or less, and the cross section of the flow path is cut. _S a / _{S B} is the relationship between the area _{S B} (μm ²⁾ is less than 0.005 (μm ^-1) or more 0.04 (μm ^-1), a vapor chamber.

  The flow path has a plurality of condensate flow paths through which the liquid obtained by condensing the working fluid and a vapor flow path through which the vapor obtained by vaporizing the working fluid flows, and the wall is formed between adjacent condensate flow paths. You may comprise so that it may be the wall made. Further, the width of the condensate channel may be 10 μm or more and 300 μm or less, and a groove may be formed on the surface of the condensate channel.

  The wall may be configured to have a plurality of openings that communicate with adjacent flow paths. And the opening part can also be provided so that a position may differ in the direction where a flow path extends in an adjacent wall.

  To provide an electronic device comprising a housing, an electronic component disposed inside the housing, and the vapor chamber disposed in contact with the electronic component directly or via another member. it can.

  According to the present invention, even if the thickness is reduced, it is possible to ensure a large proportion of the flow path in the space in which the working fluid is sealed, so that the heat transport capability can be maintained high, and the wall between the flow paths Is in a form with the required strength. Therefore, even when used in an environment where the working fluid freezes, all of the thickness reduction, heat transport capability, and durability are satisfied.

FIG. 1A is a perspective view of the vapor chamber 1, and FIG. 1B is an exploded perspective view of the vapor chamber 1. FIG. 2A is a perspective view of the first sheet 10, and FIG. 2B is a plan view of the first sheet 10. FIG. 3 is a cut surface of the first sheet 10. FIG. 4A and FIG. 4B are other cut surfaces of the first sheet 10. FIG. 5 is an enlarged view of a part of the outer peripheral liquid flow path portion 14 in plan view. FIG. 6A to FIG. 6C are views showing other forms of walls and liquid communication openings. FIG. 7 is an enlarged view of a part of the peripheral liquid channel portion 14 of another example in plan view. FIG. 8A is a cross-sectional view focusing on the inner liquid flow path portion 15, and FIG. 8B is an enlarged view of a part of the inner liquid flow path portion 15 in plan view. FIG. 9A is a perspective view of the second sheet 20, and FIG. 9B is a plan view of the second sheet 20. FIG. 10 is a cut surface of the second sheet 20. FIG. 11 is another cut surface of the second sheet 20. FIG. 12 is a cut surface of the vapor chamber 1. FIG. 13 is an enlarged view of a part of FIG. FIG. 14 is a cut surface of the wall 15 b and the two condensate flow paths 3. FIG. 15 is a cross-sectional view taken along XV-XV in FIG. 16 is a cross-sectional view taken along the line XVI-XVI in FIG. FIG. 17A and FIG. 17B are views for explaining the concept of wall durability. FIG. 18 is a diagram illustrating a modification. FIG. 19 is a diagram for explaining another modified example. FIG. 20 is a diagram for explaining another modification. FIG. 21 is a perspective view illustrating the electronic device 40. FIG. 22 is a view for explaining the operation of the vapor chamber 1.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings. However, the present invention is not limited to these forms. In the drawings shown below, the size and ratio of members may be changed or exaggerated for easy understanding. In addition, for ease of viewing, illustrations of parts unnecessary for description and repetitive symbols may be omitted.

  FIG. 1A is an external perspective view of a vapor chamber 1 according to one embodiment, and FIG. 1B is an exploded perspective view of the vapor chamber 1. In these drawings and the following drawings, arrows (x, y, z) indicating directions orthogonal to each other are also shown for convenience as necessary. Here, the xy in-plane direction is a direction along the plate surface of the vapor chamber 1 having a flat plate shape, and the z direction is a thickness direction.

  The vapor chamber 1 has a first sheet 10 and a second sheet 20 as can be seen from FIGS. 1 (a) and 1 (b). Then, as will be described later, the first sheet 10 and the second sheet 20 are overlapped and bonded (diffusion bonding, brazing, etc.) to thereby provide a space between the first sheet 10 and the second sheet 20. A sealed space 2 is formed in the closed space 2 (see, for example, FIG. 12), and a working fluid is sealed in the sealed space 2.

In this embodiment, the first sheet 10 is a sheet-like member as a whole. 2A is a perspective view of the first sheet 10 viewed from the inner surface 10a side, and FIG. 2B is a plan view of the first sheet 10 viewed from the inner surface 10a side. FIG. 3 shows a cut surface of the first sheet 10 when cut along III-III in FIG.
The first sheet 10 includes an inner surface 10a, an outer surface 10b opposite to the inner surface 10a, and a side surface 10c that connects the inner surface 10a and the outer surface 10b to form a thickness, and the working fluid flows back to the inner surface 10a side. A pattern for the flow path is formed. As will be described later, the sealed space 2 is formed by overlapping the inner surface 10a of the first sheet 10 and the inner surface 20a of the second sheet 20 so as to face each other.

Such a first sheet 10 includes a main body 11 and an injection part 12. The main body 11 has a sheet shape that forms a portion where the working fluid recirculates. In this embodiment, the main body 11 has a rectangular shape with a circular arc (so-called R) in plan view.
The injection part 12 is a part that injects the working fluid into the sealed space 2 (for example, see FIG. 12) formed by the first sheet 10 and the second sheet 20. In this embodiment, the side that is rectangular in plan view of the main body 11. It is a sheet shape of a quadrangle in a plan view protruding from. In this embodiment, the injection portion 12 of the first sheet 10 is flat on both the inner surface 10a side and the outer surface 10b side.

Although the thickness of such a 1st sheet | seat 10 is not specifically limited, 0.1 mm or more and 1.0 mm or less are preferable. Thereby, the scene which can be applied as a thin vapor chamber can be increased.
Moreover, although the material which comprises the 1st sheet | seat 10 is not specifically limited, It is preferable that it is a metal with high heat conductivity. Examples of this include copper and copper alloys. In particular, by using copper and a copper alloy, it becomes easy to produce a vapor chamber by etching and diffusion bonding as will be described later while improving the heat transport capability.

  On the inner surface 10a side of the main body 11, a structure for returning the working fluid is formed. Specifically, on the inner surface 10a side of the main body 11, an outer peripheral joint portion 13, an outer peripheral liquid flow passage portion 14, an inner liquid flow passage portion 15, a vapor flow passage groove 16, and a vapor flow passage communication groove 17 are provided. Configured.

The outer peripheral joint 13 is a surface formed on the inner surface 10 a side of the main body 11 along the outer periphery of the main body 11. The outer peripheral joint 13 is overlapped with the outer peripheral joint 23 of the second sheet 20 and joined (diffusion joining, brazing, etc.), thereby forming a sealed space 2 between the first sheet 10 and the second sheet 20. The working fluid is sealed here.
FIG. 2 (b), the can be set appropriately as required width of the outer peripheral joint 13 shown in _{A 10} in FIG. 3, is preferably 0.8mm or more 3mm or less. If this width is smaller than 0.8 mm, there is a possibility that the joining area will be insufficient when a positional deviation occurs during joining of the first sheet and the second sheet. In addition, if the width is larger than 3 mm, the internal volume of the sealed space is reduced, and there is a possibility that a sufficient steam flow path or condensate flow path cannot be secured.

  In addition, holes 13 a penetrating in the thickness direction (z direction) are provided at the four corners of the main body 11 in the outer peripheral joint portion 13. This hole functions as a positioning means at the time of overlapping with the second sheet 20.

  The outer peripheral liquid flow path part 14 functions as a liquid flow path part, and is a part constituting a part of the condensate flow path 3 (see, for example, FIG. 13) that is a flow path when the working fluid is condensed and liquefied. is there. FIG. 4A shows the portion indicated by arrow IVa in FIG. 3, and FIG. 4B shows the cut surface of the site cut by IVb-IVb in FIG. 2B. In any of the drawings, the cross-sectional shape of the outer peripheral liquid flow path portion 14 appears. FIG. 5 shows an enlarged view of the outer peripheral liquid flow path portion 14 viewed from the direction indicated by the arrow V in FIG.

As can be seen from these drawings, the outer peripheral liquid flow path portion 14 is formed along the inner side of the outer peripheral joint portion 13 in the inner surface 10 a of the main body 11, and is provided so as to be annular along the outer periphery of the sealed space 2. Yes. Further, the outer peripheral liquid flow path portion 14 is formed with a liquid flow path groove 14a which is a plurality of grooves extending in parallel with the outer peripheral direction of the main body 11, and the plurality of liquid flow path grooves 14a are formed by the liquid flow path grooves 14a. They are arranged at intervals in a direction different from the extending direction. Therefore, as can be seen from FIGS. 4 (a) and 4 (b), the outer peripheral liquid flow path portion 14 has a wall which is a convex portion between the liquid flow channel groove 14a and the liquid flow path groove 14a which are concave in the cross section. 14b is formed by repeating the unevenness.
Here, since the liquid channel groove 14a is a groove, in the cross-sectional shape thereof, an opening is provided in a bottom portion and a portion opposite to the bottom portion.

  In addition, by providing a plurality of liquid flow channel grooves 14a in this way, the depth and width of each liquid flow channel groove 14a are reduced, and the flow of the condensate flow channel 3 (see, for example, FIG. 13) is cut off. A large capillary force can be used by reducing the area. On the other hand, the total volume of the condensate flow path 3 as a whole is ensured by providing a plurality of liquid flow path grooves 14a, and a condensate having a necessary flow rate can be flowed.

  Further, as can be seen from FIG. 5, in the outer peripheral liquid flow path portion 14, the adjacent liquid flow path grooves 14 a communicate with each other through a liquid communication opening portion 14 c provided with a space in the wall 14 b. Thereby, equalization of the amount of condensate is promoted between the plurality of liquid flow channel grooves 14a, the condensate can be efficiently flowed, and the working fluid can be smoothly circulated. Further, the liquid communication opening 14 c provided in the wall 14 b adjacent to the steam channel groove 16 that forms the steam channel 4 connects the steam channel 4 and the condensate channel 3. Therefore, the condensate generated in the steam flow path 4 can be smoothly moved to the condensate flow path 3 by configuring the liquid communication opening 14c, and the working fluid can be smoothly recirculated.

6A to 6C, one condensate flow path 14a, two walls 14b sandwiching the condensate flow path 14a, and one liquid provided on each wall 14b from the same viewpoint as that of FIG. The figure which showed the communication opening part 14c was represented. In any of these, the shape of the wall 14b is different from the example of FIG. 5 at the viewpoint (plan view).
That is, in the wall 14b shown in FIG. 5, the width (C ₁₀₂ ) is the same as that of the other part at the end where the liquid communication opening 14c is formed, and is constant. On the other hand, in the wall 14b having the shape shown in FIGS. 6A to 6C, the width at the end portion where the liquid communication opening 14c is formed is larger than the maximum width (C ₁₀₂ ) of the wall 14b. Is formed to be smaller. More specifically, in the example of FIG. 6 (a), the corner has an arcuate shape at the end, and an R is formed at the corner, thereby reducing the width of the end, and FIG. 6 (b) has an end. An example in which the width of the end portion is reduced by being semicircular, and FIG. 6C is an example in which the end portion is tapered so as to be sharp.

As shown in FIGS. 6A to 6C, the width of the end of the wall 14b where the liquid communication opening 14c is formed is smaller than the maximum width (C ₁₀₂ ) of the wall 14b. As a result, the working fluid can easily move through the liquid communication opening 14c, the working fluid can be easily moved to the adjacent condensate flow path 3, and the working fluid can be smoothly circulated. .
On the other hand, when the vapor chamber is not operated, the working fluid accumulated in the vicinity of the liquid communication opening 14c is frozen and the volume is increased, as will be described later. At that time, when a force acting in the direction of separating the first sheet and the second sheet is applied, the end of the wall 14b is thinned in this way, so stress concentrates on the thinned part and the wall 14b It will be easy to be destroyed. However, in this embodiment, even in such a case, the wall 14b is not broken and has sufficient durability.

In this embodiment, as shown in FIG. 5, the liquid communication opening 14c is arranged so as to face the same position in the direction in which the liquid flow channel groove 14a extends across the groove of one liquid flow channel groove 14a. However, the present invention is not limited to this. For example, as shown in FIG. 7, the liquid communication openings 14c are located at different positions in the direction in which the liquid flow channel groove 14a extends across the groove of one liquid flow channel groove 14a. It may be arranged. In other words, in this case, the liquid communication opening 14c is arranged offset.
By providing the liquid communication opening 14c by offsetting in this way, the liquid communication opening 14c does not appear simultaneously on both sides when viewed from the working fluid traveling in the condensate flow path 3, and the liquid communication opening 14c. Even if appears, the wall 14b always exists on at least one side surface. Therefore, capillary force can be obtained continuously. Since the capillary force acting on the working fluid can be maintained high by offsetting from this point of view to form the liquid communication opening 14c, smoother reflux is possible.
On the other hand, when the vapor chamber is not in operation, a large amount of condensate tends to accumulate in the liquid communication opening 14c as compared with the example of FIG. 5 due to such a strong capillary force. Then, as will be described later, when the working fluid freezes and the volume increases, a greater force is applied in the direction of separating the first sheet and the second sheet, that is, the direction of breaking the wall 14b. However, in this embodiment, this is the case, and the wall 14b has sufficient durability without being destroyed.

  In addition, even when the liquid communication openings 14c are offset and arranged in this manner, the end shape of the wall 14b can be configured in accordance with the example of FIGS. 6 (a) to 6 (c).

It is preferable that the outer periphery liquid flow path part 14 provided with the above structures is further provided with the following structure.
Width in FIG. 2 (b), FIG. 3, FIG. 4 (a), the outer peripheral fluid passage section 14 shown in B ₁₀ in FIG. 4 (b), can be appropriately set from the size of the entire vapor chamber However, it is preferable that it is 0.3 mm or more and 2 mm or less. If this width is smaller than 0.3 mm, there is a risk that a sufficient amount of the liquid refluxing outside cannot be obtained. Further, if this width exceeds 2 mm, there is a possibility that sufficient space for the inner condensate flow path and the steam flow path cannot be obtained.

For liquid flow path grooves 14a, FIG. 4 (a), the 5, it is preferable groove width indicated by _{C 101} in FIG. 6 (a) ~ FIG. 6 (c) is 10μm or more 300μm or less.
Moreover, it is preferable that the depth of the groove | channel shown by D in FIG. 4 (a), FIG.4 (b) is 5 micrometers or more and 200 micrometers or less. Thereby, the capillary force of the liquid flow path necessary for reflux can be sufficiently exhibited. Here, the groove depth D is preferably smaller than the remaining sheet thickness obtained by subtracting the groove depth D from the thickness of the first sheet 10. This can more reliably prevent the sheet from being torn when the working fluid is frozen.
From the viewpoint of exerting the capillary force of the channel more strongly, the aspect ratio (aspect ratio) in the channel cross section represented by C ₁₀₁ / D is preferably larger than 1.0 or smaller than 1.0. . Among them, C ₁₀₁ > D is preferable from the viewpoint of production, and the aspect ratio is preferably larger than 1.3.

Also, the walls 14b, FIG. 4 (a), the 5, it is preferable that the width indicated by _{C 102} in FIG. 6 (a) ~ FIG. 6 (c) is 20μm or more 300μm or less. If this width is smaller than 20 μm, the working fluid is likely to break due to repeated freezing and melting. If this width is larger than 300 μm, the width of the liquid communication opening 14 c becomes too large, and the adjacent condensate flow path 3 There is a possibility that the smooth communication of the working fluid is hindered.

For Ekiren communication opening portion 14c, the size of the opening along the liquid flow path grooves 14a shown extend at C ₃ in Figure 5 is preferably 20μm or more 180μm or less.
Further, it is preferable that the pitch of Ekiren communication opening portion 14c adjacent in the extending direction the liquid flow path groove 14a shown in _{C 4} in FIG. 5 is 300μm or more 2700μm or less.

  In this embodiment, the cross-sectional shape of the liquid channel groove 14a is a semi-elliptical shape, but is not limited thereto, and is not limited to a square, a rectangle such as a trapezoid, a triangle, a semi-circle, a semi-circular bottom, and a semi-elliptical bottom. Etc.

  Returning to FIG. 2 and FIG. 3, the inner liquid flow path portion 15 will be described. The inner liquid flow path portion 15 also functions as a liquid flow path portion, and is a part constituting a part of the condensate flow path 3 through which the working fluid is condensed and liquefied. FIG. 8A shows a portion indicated by VIIIa in FIG. Also in this figure, the cross-sectional shape of the inner liquid flow path portion 15 appears. Further, FIG. 8B shows an enlarged view of the inner liquid flow path portion 15 viewed from the direction indicated by the arrow VIIIb in FIG. 8A.

As can be seen from these drawings, the inner liquid flow path portion 15 is formed on the inner surface 10 a of the main body 11 inside the ring of the outer peripheral liquid flow path portion 14 that is annular. As can be seen from FIGS. 2A and 2B, the inner liquid flow path portion 15 of the present embodiment is a ridge that is rectangular in plan view of the main body 11 and extends in a direction parallel to the long side (x direction). A plurality (three in this embodiment) of the inner liquid flow path portions 15 are arranged at intervals in a direction (y direction) parallel to the short side.
Each inner liquid flow path section 15 is formed with a liquid flow path groove 15a that is a groove parallel to the direction in which the inner liquid flow path section 15 extends, and a plurality of liquid flow path grooves 15a includes the liquid flow path grooves 15a. They are arranged at a predetermined interval in a direction different from the extending direction. Therefore, as can be seen from FIGS. 3 and 8A, the inner liquid flow path portion 15 has a liquid flow channel groove 15a that is a concave portion in the cross section and a wall 15b that is a convex portion between the liquid flow channel grooves 15a. Unevenness is repeated.
Here, since the liquid channel groove 15a is a groove, an opening is provided in the cross-sectional shape of the bottom portion and a portion on the opposite side facing the bottom portion.

  By providing a plurality of liquid flow channel grooves 15a in this way, the depth and width of each liquid flow channel groove 15a are reduced, and the cross-sectional area of the condensate flow channel 3 (see FIG. 13) is reduced. Thus, a large capillary force can be used. On the other hand, by providing a plurality of liquid flow channel grooves 15a, the total volume of the condensate flow channel 3 as a whole is ensured to have a suitable size, and a condensate having a necessary flow rate can be flowed.

  Further, as can be seen from FIG. 8B, in the inner liquid flow path portion 15, the liquid flow groove 15a adjacent to the wall 15b is formed in the same manner as in FIG. The liquid communication openings 15c are provided at intervals so as to communicate with each other. Thereby, equalization of the amount of condensate is promoted between the plurality of liquid passage grooves 15a, the condensate can be efficiently flowed, and the working fluid can be smoothly circulated. Further, the liquid communication opening 15 c provided in the wall 15 b adjacent to the steam channel groove 16 that forms the steam channel 4 allows the steam channel 4 and the condensate channel 3 to communicate with each other. Therefore, the condensate generated in the steam channel 4 can be smoothly moved to the condensate channel 3 by configuring the liquid communication opening 15c as will be described later. Reflux is possible.

The inner liquid flow path portion 15 also has a width at the end where the liquid communication opening portion 15c is formed with respect to the wall 15b, following the example of FIGS. 6 (a) to 6 (c). You may make it form so that it may become significantly smaller.
As a result, the working fluid can easily move through the liquid communication opening 15c, and the working fluid can be smoothly circulated.
On the other hand, when the vapor chamber is not in operation, the working fluid accumulated in the vicinity of the liquid communication opening 15c is frozen to increase the volume, as will be described later. At that time, when a force acting in the direction of separating the first sheet and the second sheet is applied, the end of the wall 15b is thinned in this way, so stress concentrates on the thinned portion and the wall 15b It will be easy to be destroyed. However, in this embodiment, even in such a case, the wall 15b has sufficient durability without being broken.

Further, for the inner liquid flow path portion 15, following the example of FIG. 7, the liquid communication opening 15 c is provided at a different position in the direction in which the liquid flow path groove 15 a extends across the groove of one liquid flow path groove 15 a. It may be arranged.
By providing the liquid communication opening 15c by offsetting in this way, the liquid communication opening 15c does not appear simultaneously on both sides when viewed from the working fluid traveling in the condensate flow path 3, and the liquid communication opening 15c. Even if appears, the wall 15b always exists on at least one side surface. Therefore, capillary force can be obtained continuously. Since the capillary force acting on the working fluid can be maintained high by offsetting from this point of view and forming the liquid communication opening 15c, smoother reflux is possible.
On the other hand, when the vapor chamber is not in operation, a large amount of condensate tends to accumulate in the liquid communication opening 15c as compared with the example of FIG. Then, as will be described later, when the working fluid freezes and the volume increases, a greater force is applied in the direction of separating the first sheet and the second sheet, that is, the direction of breaking the wall 15b. However, in this embodiment, in this case, the wall 15b has sufficient durability without being destroyed.
In addition, even when the liquid communication openings 15c are offset and arranged in this manner, the end shape of the wall 15b can be configured according to the examples of FIGS. 6 (a) to 6 (c).

It is preferable that the inner liquid flow path part 15 provided with the above configuration further includes the following configuration.
FIG. 2 (b), the width of 3, the inner liquid channel section 15 shown in _{G 10} in FIG. 8 is preferably 100μm or 2000μm or less. Moreover, it is preferable that the pitch of the some inner side liquid flow-path part 15 is 200 micrometers or more and 4000 micrometers or less. Thereby, the flow path resistance of the steam channel can be sufficiently lowered, and the movement of the steam and the reflux of the condensate can be performed in a balanced manner.

For liquid flow path grooves 15a, FIG. 8 (a), the it is preferred that the groove width shown in the _{H 101} in FIG. 8 (b) is 10μm or more 300μm or less.
Further, the depth of the groove indicated by J in FIG. 8A is preferably 5 μm or more and 200 μm or less. Thereby, the capillary force of the condensate flow path required for reflux can be sufficiently exhibited. Here, the groove depth J is preferably smaller than the remaining sheet thickness obtained by subtracting the groove depth J from the thickness of the first sheet 10. This can more reliably prevent the sheet from being torn when the working fluid is frozen.
From the viewpoint of exerting the capillary force of the channel more strongly, the aspect ratio (aspect ratio) in the channel cross section represented by H ₁₀₁ / J is preferably larger than 1.0 or smaller than 1.0. . Among them, H ₁₀₁ > J is preferable from the viewpoint of production, and the aspect ratio is preferably larger than 1.3.

In addition, with respect to the wall 15b, the width indicated by _H102 in FIGS. 8A and 8B is preferably 20 μm or more and 300 μm or less. If this width is smaller than 20 μm, the working fluid is likely to be broken due to repeated freezing and melting. May be disturbed.

For Ekiren communication opening 15c, it is preferable the size of the opening along the liquid flow path grooves 15a shown extend at _{H 3} in FIG. 8 (b) is 20μm or more 180μm or less.
Further, it is preferable that the pitch of Ekiren communication opening portion 15c adjacent in the direction in which the liquid flow path groove 15a shown extend at _{H 4} in FIG. 8 (b) is 300μm or more 2700μm or less.

  In this embodiment, the cross-sectional shape of the liquid channel groove 15a is a semi-elliptical shape. However, the shape is not limited to this, and the shape is not limited to this. Etc.

  Next, the steam channel groove 16 will be described. The steam channel groove 16 is a part through which the vapor evaporated from the working fluid evaporates and constitutes a part of the steam channel 4. FIG. 2B shows the shape of the steam channel groove 16 in plan view, and FIG. 3 shows the cross-sectional shape of the steam channel groove 16.

As can be seen from these figures, the steam channel groove 16 is constituted by a groove formed on the inner side of the inner surface 10a of the main body 11 inside the ring of the outer peripheral liquid channel portion 14 that is annular. Specifically, the steam channel groove 16 of the present embodiment is formed between the adjacent inner liquid channel portions 15 and between the outer peripheral liquid channel portion 14 and the inner liquid channel portion 15, and is a plan view of the main body 11. It is a rectangular groove extending in the direction parallel to the long side (x direction). A plurality (four in this embodiment) of the steam flow channel 16 are arranged in a direction (y direction) parallel to the short side. Therefore, as can be seen from FIG. 3, the first sheet 10 is repeatedly uneven in the y direction with the outer peripheral liquid flow path portion 14 and the inner liquid flow path portion 15 as ridges and the vapor flow path groove 16 as a ridge. It has a different shape.
Here, since the steam channel groove 16 is a groove, in the cross-sectional shape thereof, an opening is provided in a bottom portion and a portion on the opposite side facing the bottom portion.

The steam channel groove 16 having such a configuration preferably further has the following configuration.
FIG. 2 (b), the width of the steam flow passage 16 shown in _{M 10} in FIG. 3, at least the above-mentioned liquid flow path groove 14a, the width _{C 101} of 15a, is larger than the width _{H 101,} 100 [mu] m or more 2000μm or less It is preferable that Further, the pitch of the steam channel grooves 16 is usually determined by the pitch of the inner liquid channel portion 15.
On the other hand, the depth of the steam flow passage 16 shown in _{N 10} in FIG. 3, at least the above-mentioned liquid flow path groove 14a, the depth D of 15a, are formed larger than the depth J, it is 10μm or more 300μm or less Is preferred.
In this way, by making the flow channel cross-sectional area of the vapor flow channel groove larger than that of the liquid flow channel groove, the vapor having a volume larger than that of the condensate can be smoothly refluxed due to the nature of the working fluid.

Here, when the steam channel 4 is formed in combination with the second sheet 20 to form the steam channel 4 as described later, the width of the steam channel 4 is high (thickness direction size). It is preferable to be configured so as to have a larger flat shape. Therefore, the aspect ratio represented by M ₁₀ / N ₁₀ is preferably 4.0 or more, more preferably 8.0 or more.

  In this embodiment, the cross-sectional shape of the steam channel groove 16 is a semi-elliptical shape, but is not limited to this, a square, a rectangle, a trapezoidal square, a triangle, a semi-circle, a bottom is a circle, a bottom is a semi-ellipse, etc. Also good.

  The steam channel communication groove 17 is a groove that allows the plurality of steam channel grooves 16 to communicate with each other. Thereby, equalization of the vapor | steam of the some vapor | steam flow path groove | channel 16 is achieved, or a vapor | steam is conveyed to a wider range so that the condensate flow path 3 by many liquid flow path grooves 14a and 15a can be utilized efficiently. It becomes. As a result, the working fluid can be more smoothly recirculated.

  As can be seen from FIGS. 2A and 2B, the steam channel communication groove 17 of this embodiment has both ends in the direction in which the inner liquid channel portion 15 extends and both ends in the direction in which the steam channel groove 16 extends. And the outer peripheral liquid flow path portion 14. FIG. 4B shows a cross section perpendicular to the communication direction of the steam flow channel communication groove 17. In addition, since the boundary between the steam flow path communication groove 17 and the steam flow path 16 is not necessarily formed by the shape, the boundary is not shown in FIGS. 2A and 2B for the sake of easy understanding. Represented by a dotted line.

The steam channel communication groove 17 only needs to be formed so that adjacent steam channel grooves 16 communicate with each other, and the shape thereof is not particularly limited. For example, the steam channel communication groove 17 can have the following configuration. .
FIG. 2 (b), the width of the steam channel communicating groove 17 shown in _{P 10} in FIG. 4 (b) is preferably 100μm or 1000μm or less.
FIG. 4 (b) the depth of the steam flow path communicating groove 17 shown in _{Q 10} is preferably 10μm or more 300μm or less, the same as the depth _{N 10} of the steam flow passage 16 among them It is preferable. This facilitates manufacturing.

  In this embodiment, the cross-sectional shape of the steam flow path communication groove 17 is a semi-elliptical shape, but is not limited to this, a square, a rectangle, a trapezoidal quadrangle, a triangle, a semi-circle, a bottom semi-circular, a bottom semi-elliptical, etc. It may be.

Next, the second sheet 20 will be described. In this embodiment, the second sheet 20 is also a sheet-like member as a whole. 9A is a perspective view of the second sheet 20 viewed from the inner surface 20a side, and FIG. 9B is a plan view of the second sheet 20 viewed from the inner surface 20a side. FIG. 10 shows a cut surface of the second sheet 20 when cut by XX in FIG. FIG. 11 shows a cut surface of the second sheet 20 when cut by XI-XI in FIG.
The second sheet 20 includes an inner surface 20a, an outer surface 20b opposite to the inner surface 20a, and a side surface 20c that connects the inner surface 20a and the outer surface 20b to form a thickness, and a pattern in which the working fluid flows back to the inner surface 20a side. Is formed. As will be described later, the sealed space 2 is formed by overlapping the inner surface 20a of the second sheet 20 and the inner surface 10a of the first sheet 10 so as to face each other.

Such a second sheet 20 includes a main body 21 and an injection part 22. The main body 21 is a sheet-like part that forms a part where the working fluid recirculates. In this embodiment, the main body 21 has a rectangular shape with a circular arc (so-called R) in plan view.
The injection part 22 is a part that injects the working fluid into the sealed space 2 (see FIG. 12) formed by the first sheet 10 and the second sheet 20. In this embodiment, the side that is rectangular in plan view of the main body 21. It is a sheet shape of a quadrangle in a plan view protruding from. In the present embodiment, the injection groove 22a is formed on the inner surface 20a side of the injection portion 22 of the second sheet 20, and communicates from the side surface 20c of the second sheet 20 to the inside of the main body 21 (site to be the sealed space 2). ing.
The thickness and material of the second sheet 20 can be considered in the same manner as the first sheet 10.

  On the inner surface 20a side of the main body 21, a structure for returning the working fluid is formed. Specifically, on the inner surface 20a side of the main body 21, an outer peripheral joint portion 23, an outer peripheral liquid flow passage portion 24, an inner liquid flow passage portion 25, a vapor flow passage groove 26, and a vapor flow passage communication groove 27 are provided. ing.

The outer peripheral joint portion 23 is a surface formed on the inner surface 20 a side of the main body 21 along the outer periphery of the main body 21. The outer peripheral joint 23 is overlapped with the outer peripheral joint 13 of the first sheet 10 and bonded (diffusion bonding, brazing, etc.) to form a sealed space 2 between the first sheet 10 and the second sheet 20. The working fluid is sealed here.
FIG. 9 (b), the 10, it is preferable that the width of the outer peripheral joint 23 shown in _{A 20} in FIG. 11 is the same as the width _{A 10} of the outer joint portion 13 of the body 11 described above.

  In addition, holes 23 a penetrating in the thickness direction (z direction) are provided at the four corners of the main body 21 in the outer peripheral joint portion 23. The hole 23a functions as a positioning means when overlapping with the first sheet 10.

  The outer peripheral liquid flow path part 24 is a liquid flow path part, and is a part constituting a part of the condensate flow path 3 through which the working fluid is condensed and liquefied.

The outer peripheral liquid flow path portion 24 is formed along the inner side of the outer peripheral joint portion 23 in the inner surface 20 a of the main body 21, and is formed so as to form an annular shape along the outer periphery of the sealed space 2. In this embodiment, the outer peripheral liquid flow path portion 24 of the second sheet 20 is a flat surface and is flush with the outer peripheral joint portion 23 before joining to the first sheet 10 as can be seen from FIGS. 10 and 11. Thereby, the condensate flow path 3 is formed by closing at least some of the liquid flow path grooves 14a of the plurality of liquid flow path grooves 14a of the first sheet 10 described above. Detailed aspects regarding the combination of the first sheet 10 and the second sheet 20 will be described later.
In this way, in the second sheet 20, the outer peripheral joint portion 23 and the outer peripheral liquid flow passage portion 24 are flush with each other, and thus there is no boundary line that distinguishes the two structurally. However, for ease of understanding, the boundary between the two is represented by a dotted line in FIG. 9B.

It is preferable that the outer periphery liquid flow path part 24 is provided with the following structures.
The width B ₂₀ of the outer peripheral liquid flow path portion 24 shown in FIGS. 9B, 10, and 11 is not particularly limited, and is the same as the width B ₁₀ of the outer peripheral liquid flow path portion 14 of the first sheet 10. However, it may be small. In this embodiment, the width B ₁₀ and the width B ₂₀ are the same.
And the width B ₂₀ smaller than the width B _10, at least part of the outer circumferential fluid flow path portion 14, the opening of the liquid flow path grooves 14a are opened without being closed by the outer peripheral liquid flow path portion 24, the condensate from here Since it is easy to enter, the condensate can be more smoothly refluxed.

  Next, the inner liquid flow path part 25 will be described. The inner liquid flow path portion 25 is also a liquid flow path portion and is one part constituting the condensate flow path 3.

As can be seen from FIGS. 9A, 9B, 10 and 11, the inner liquid flow path portion 25 is an annular ring of the outer peripheral liquid flow path portion 24 in the inner surface 20a of the main body 21. It is formed inside. The inner liquid flow path portion 25 of the present embodiment is a ridge extending in a direction (x direction) parallel to the long side in a rectangular shape in plan view of the main body 21, and a plurality (three in this embodiment) of the inner liquid flow path portions 25. Are arranged at a predetermined interval in a direction parallel to the short side (y direction).
In this embodiment, each inner liquid flow path portion 25 is formed such that the surface on the inner surface 20a side becomes a flat surface before joining to the first sheet 10. Thereby, the condensate flow path 3 is formed by closing at least some of the liquid flow path grooves 15a of the plurality of liquid flow path grooves 15a of the first sheet 10 described above.
In addition, when the groove | channel for forming the condensate flow path 3 is not formed in the inner side liquid flow path part 25 like this form, the thickness of the 2nd sheet | seat 20 is the liquid flow path groove | channel of the 1st sheet | seat 10. It is preferable that it is more than the depth J of 15a (refer FIG. 8 (a)). Thereby, the fracture | rupture (break) in the 2nd sheet | seat side in a vapor chamber can be prevented.

The width G ₂₀ of the inner liquid flow path portion 25 shown in FIGS. 9B and 10 is not particularly limited, and may be the same as the width G ₁₀ of the inner liquid flow path portion 15 of the first sheet 10. , May be different. In this embodiment are the same as the width _{G 10} and width _{G 20.}
It is possible to reduce the influence of positional deviation at the time of bonding and the width G ₂₀ and width G ₁₀ are different. When the width G ₂₀ is smaller than the width G _10, at least a part of the inner liquid flow path portion 15 opens the liquid flow channel groove 15 a without being closed by the inner liquid flow path portion 25. Since the condensate easily enters from here, the condensate can be more smoothly refluxed.

  Next, the steam channel groove 26 will be described. The steam channel groove 26 is a portion through which vapor vaporized by evaporation of the working fluid passes and constitutes a part of the steam channel 4. FIG. 9B shows the shape of the steam channel groove 26 in plan view, and FIG. 10 shows the cross-sectional shape of the steam channel groove 26.

As can be seen from these drawings, the steam flow path groove 26 is formed by a groove formed inside the ring of the outer peripheral liquid flow path portion 24 that is annular in the inner surface 20 a of the main body 21. Specifically, the steam channel groove 26 of this embodiment is formed between the adjacent inner liquid channel portions 25 and between the outer peripheral liquid channel portion 24 and the inner liquid channel portion 25, and is a plan view of the main body 21. It is a rectangular groove extending in the direction parallel to the long side (x direction). A plurality (four in this embodiment) of steam flow channel grooves 26 are arranged in a direction (y direction) parallel to the short side. Therefore, as can be seen from FIG. 10, the second sheet 20 is formed with protrusions that project the outer peripheral liquid flow path portion 24 and the inner liquid flow path portion 25 in the y direction, and the vapor flow path groove 26 is concave. A concave line is formed, and a shape in which these irregularities are repeated is provided.
Here, since the steam channel groove 26 is a groove, an opening is provided in the cross-sectional shape of the bottom portion and a portion opposite to the bottom portion.

It is preferable that the steam channel groove 26 is disposed at a position overlapping the steam channel groove 16 of the first sheet 10 in the thickness direction when combined with the first sheet 10. Thereby, the steam channel 4 can be formed by the steam channel groove 16 and the steam channel groove 26.
FIG. 9 (b), the width of the steam flow path groove 26 shown in M ₂₀ in FIG. 10 is not particularly limited, and may the same as the width M ₁₀ of the steam flow path groove 16 of the first sheet 10, May be different. In this embodiment are the same as the width _{M 10} and width _{M 20.}
When the width M ₂₀ and width M ₁₀ are different, it is possible to reduce the influence of positional deviation at the time of bonding. Note that when increasing the width M ₂₀ than the width M _10, at least a portion of the inner fluid passage 15, the opening of the liquid flow path grooves 15a are opened without being closed by the inner fluid flow path portion 25 Since the condensate easily enters from here, the condensate can be more smoothly refluxed.
On the other hand, the depth of the steam flow path groove 26 shown in _{N 20} in FIG. 10 is preferably 10μm or more 300μm or less.

Here, when the steam channel 4 is formed in combination with the first sheet 10 as described later, the steam channel groove 26 has a high width (size in the thickness direction). It is preferable to be configured so as to have a larger flat shape. Therefore, the aspect ratio represented by M ₂₀ / N ₂₀ is preferably 4.0 or more, and more preferably 8.0 or more.

  In the present embodiment, the cross-sectional shape of the vapor channel groove 26 is a semi-elliptical shape, but it may be a quadrangle such as a square, a rectangle or a trapezoid, a triangle, a semi-circle, a semi-circular bottom, a semi-elliptical bottom, or the like.

  The steam channel communication groove 27 is a groove that allows the plurality of steam channel grooves 26 to communicate with each other, and constitutes a part of the steam channel 4. As a result, the vapors of the plurality of vapor channels 4 are equalized, or the vapors are transported to a wider range, so that many condensate channels 3 can be used efficiently. The reflux can be made smoother.

  As shown in FIGS. 9B and 11, the steam channel communication groove 27 of the present embodiment includes both ends in the direction in which the inner liquid channel portion 25 extends and both ends in the direction in which the steam channel groove 26 extends, It is formed between the peripheral liquid channel portion 24. FIG. 11 shows a cross section perpendicular to the communication direction of the steam flow channel communication groove 27.

FIG. 9 (b), the width of the steam channel communicating groove 27 shown in P ₂₀ 11 is not particularly limited, the same as the width P ₁₀ of the steam channel communication groove 17 of the first sheet 10 even good, it may be greater than the width P _10.
When the width P ₂₀ is larger than the width P ₁₀ , the opening of the liquid flow channel groove 14 a forms a part of the vapor flow channel 4 in at least a part of the outer peripheral liquid flow channel portion 14 of the first sheet 10. Therefore, the condensate can easily enter, and the condensate can be recirculated more smoothly.

The size of the width _{P 20} is preferably 200μm or less in the range of 50 [mu] m, the depth of the steam flow path communicating groove 27 shown in _{Q 20} in FIG. 11 is preferably 10μm or more 300μm or less.

  In this embodiment, the cross-sectional shape of the steam flow path communication groove 27 is a semi-elliptical shape, but is not limited to this, a square, a rectangle, a trapezoidal quadrangle, a triangle, a semi-circle, a bottom semi-circular, a bottom semi-elliptical, etc. There may be.

Next, the structure when the first sheet 10 and the second sheet 20 are combined into the vapor chamber 1 will be described. From this description, the arrangement, size, shape, and the like of each component included in the first sheet 10 and the second sheet 20 are further understood.
FIG. 12 shows a cut surface obtained by cutting the vapor chamber 1 in the thickness direction along the y direction indicated by XII-XII in FIG. This figure is a combination of the figure shown in FIG. 3 on the first sheet 10 and the figure shown in FIG. 10 on the second sheet 20 to show the cut surface of the vapor chamber 1 at this part.
FIG. 13 is an enlarged view of a portion indicated by XIII in FIG. 12, and FIG. 14 is a view of one wall 15b and the condensate flow path 3 provided on both sides of the wall 15b in FIG. An enlarged view is shown.
FIG. 15 shows a cut surface cut in the thickness direction of the vapor chamber 1 along the x direction indicated by XV-XV in FIG. This figure is a combination of the figure shown in FIG. 4B on the first sheet 10 and the figure shown in FIG. 11 on the second sheet 20 to show the cut surface of the vapor chamber 1 in this part. It is.
FIG. 16 is a sectional view taken along the line XVI-XVI in FIG.

  As can be seen from FIGS. 1 (a), 1 (b), and 12 to 16, the first sheet 10 and the second sheet 20 are arranged and bonded together to form the vapor chamber 1. ing. At this time, the inner surface 10a of the first sheet 10 and the inner surface 20a of the second sheet 20 are arranged so as to face each other, the main body 11 of the first sheet 10 and the main body 21 of the second sheet overlap, The injection part 12 and the injection part 22 of the second sheet 20 overlap. In this embodiment, the relative positional relationship between the first sheet 10 and the second sheet 20 is configured to be appropriate by aligning the positions of the hole 13a of the first sheet 10 and the hole 23a of the second sheet 20. ing.

  With such a laminate of the first sheet 10 and the second sheet 20, the components included in the main body 11 and the main body 21 are arranged as shown in FIGS. 12 to 16. Specifically, it is as follows.

  It arrange | positions so that the outer periphery junction part 13 of the 1st sheet | seat 10 and the outer periphery junction part 23 of the 2nd sheet | seat 20 may overlap, and both are joined by joining means, such as a diffusion joining and brazing. Thereby, the sealed space 2 is formed between the first sheet 10 and the second sheet 20.

The vapor chamber 1 of this embodiment is particularly effective when it is thin. From this point of view, the thickness of the vapor chamber 1 indicated by T ₀ in FIGS. 1 and 12 is 1 mm or less, more preferably 0.3 mm or less, and still more preferably 0.2 mm or less. By setting the thickness to 0.3 mm or less, in the electronic device in which the vapor chamber 1 is installed, it is often possible to install the vapor chamber in the electronic device without performing processing for forming a space for arranging the vapor chamber. According to the present embodiment, even in such a thin vapor chamber, the working fluid can be smoothly recirculated, and excellent in fracture resistance against repeated freezing and thawing of the working fluid during non-operation. It will be a thing.

It arrange | positions so that the outer periphery liquid flow-path part 14 of the 1st sheet | seat 10 and the outer periphery liquid flow-path part 24 of the 2nd sheet | seat 20 may overlap. Thereby, the condensate flow path 3 in which the condensate in which the working fluid is condensed and liquefied is formed by the liquid flow path groove 14a of the outer peripheral liquid flow path portion 14 and the outer peripheral liquid flow path portion 24.
Similarly, it arrange | positions so that the inner side liquid flow-path part 15 which is the convex line of the 1st sheet | seat 10 and the inner side liquid flow-path part 25 which is the convex line of the 2nd sheet | seat 20 may overlap. As a result, the condensate flow path 3 through which the condensate flows is formed by the liquid flow path groove 15 a of the inner liquid flow path portion 15 and the inner liquid flow path portion 25.

Here, it is preferable that the condensate flow path 3 has a flat cross-sectional shape as the vapor chamber 1 becomes thinner. As a result, the capillary force can be increased and the condensate can be moved more smoothly, so that the heat transport capability can be maintained at a high level. More specifically, in the width S _C and height S _D of the condensate channel 3 shown in FIG. 14, the ratio represented by S _C / S _D is greater than 1.0 and 4.0 or less. Is preferred.
The width _{S C} of the condensed liquid flow path 3, in the present embodiment is analogous to the width _{H 101} of Ekiryuromizo 15a, is preferably 10μm or more 300μm or less. Width S _C is less than 10μm the flow path resistance is increased transport capacity may be decreased. On the other hand, there is a possibility that transport capacity is reduced because the capillary force is reduced when the width S _C is greater than 300 [mu] m.
Further, in the present embodiment, the height _SD of the condensate flow channel 3 conforms to the depth J of the liquid flow channel groove 15a, but is preferably 5 μm or more and 200 μm or less. Thereby, the capillary force of the condensate flow path required for reflux can be sufficiently exhibited.
It should be noted that the thickness of the material portion of the first sheet and the thickness of the material portion of the second sheet at the site where the condensate flow path is formed (that is, the thickness of the vapor chamber is increased from the thickness of the vapor chamber at the site of the condensate flow path 3). The thickness of the remaining first sheet minus the thickness _SD and the thickness of the second sheet) are preferably _{equal to} or higher than the condensate flow path height _SD . Thereby, the material thickness of the first sheet and the second sheet can be sufficiently secured with respect to the height _SD of the condensate flow path, and the vapor chamber breaks (breaks) due to the condensate flow path 3. Can be further prevented.

  In this embodiment, since the liquid flow channel grooves 14a and 15a are provided only in the first sheet 10, the height of the condensate flow channel depends on the depth of the liquid flow channel grooves 14a and 15a. The liquid sheet groove may be provided not only in the second sheet 20 but also in the second sheet 20. In this case, the condensate flow path is formed by overlapping the liquid flow path groove of the first sheet and the liquid flow path groove of the second sheet, and the condensate flow according to the total depth of the bidirectional liquid flow path grooves. It becomes the height of the road.

  As shown in FIG. 16, the condensate flow path 3 is formed with a liquid communication opening 14c and a liquid communication opening 15c. Thereby, the several condensate flow path 3 connects, the equalization of a condensate is achieved, and a condensate is moved efficiently. In addition, the liquid communication openings 14 c and 15 c adjacent to the vapor flow path 4 and communicating the vapor flow path 4 and the condensate flow path 3 smoothly pass the condensate generated in the vapor flow path 4. It is possible to prevent the steam channel 4 from being blocked by the condensate.

The opening of the steam passage groove 16 of the first sheet 10 and the opening of the steam passage groove 26 of the second sheet 20 overlap each other to form a passage, which becomes the steam passage 4 through which steam flows.
Here, the vapor flow path 4 has a flat cross section as the vapor chamber 1 is made thinner. As a result, even if the thickness is reduced, the surface area in the flow path can be secured, and the heat transport capability can be maintained at a high level. More specifically, it is preferable that the ratio represented by W _B / H _B is 2.0 or more in the width W _B and the height H _B of the steam channel 4 illustrated in FIG. From the viewpoint of securing a higher heat transport capability, the ratio is more preferably 4.0 or more.

  As can be seen from FIG. 15, an overlapping flow path is formed so that the opening of the steam flow path communication groove 17 of the first sheet 10 and the opening of the steam flow path communication groove 27 of the second sheet 20 face each other, and the steam flows. It becomes the steam flow path 4. All the steam channels communicate with each other through the steam channel 4.

On the other hand, as shown in FIG. 1, the injection portions 12 and 22 overlap so that the inner surfaces 10a and 20a face each other, and the opening on the opposite side to the bottom of the injection groove 22a of the second sheet 20 is the first sheet. An injection channel 5 is formed which is closed from the inner surface 10a of the injection unit 12 and communicates between the outside and the sealed space 2 (condensate channel 3 and vapor channel 4) between the main bodies 11 and 21.
However, since the injection flow path 5 is closed after the working fluid is injected from the injection flow path 5 into the sealed space 2, the exterior and the sealed space 2 are communicated with each other in the vapor chamber 1 of the final form. Absent.

  A working fluid is sealed in the sealed space 2 of the vapor chamber 1. Although the kind of working fluid is not specifically limited, The working fluid used for a normal vapor chamber, such as a pure water, ethanol, methanol, acetone, can be used.

The vapor chamber 1 as described above preferably further includes the following configuration.
The width of the wall 15b as shown in _{S A} 14 is analogous to the width _{H 102} wall 15b of the internal fluid flow path 15 described above, its size is a 20μm or 300μm or less.
Further, the width S _A (μm) of the wall 15b is a cross-sectional area S _B (μm ² ) of the cross section of the condensate flow channel 3 adjacent to the wall 15b (the cross section in the direction orthogonal to the flow direction (flow channel longitudinal direction)). S _A / S _B is a range of 0.005 (μm ⁻¹ ) or more and 0.04 (μm ⁻¹ ) or less.

Here, the width of the wall is obtained as follows.
After cutting and polishing the vapor chamber so that the cross section of the two adjacent condensate flow channels and the wall between them appear, the cross section is 50 times to ~ using a high magnification microscope or SEM. Enlarged in 200 times range. And the outline of each internal peripheral surface of two condensate flow paths is extracted from this expanded cross section. And the distance of the narrowest part between two extracted outlines is made into the width | variety of a wall.
On the other hand, the cross section of the flow path recognizes its shape from the contour obtained in the above direction, and the largest distance in the width direction (y direction) among the obtained contours is the flow path width S _C and the thickness of the contour. The largest distance in the direction (z direction) is defined as height _SD . And each the shape of the cross section of the condensate flow path by the recognized contour obtain channel sectional area S _B as follows.
-Channel cross-sectional area when the channel cross section is rectangular S _B = S _C · S _D
-Channel cross-sectional area when the channel cross section is triangular S _B = S _C · S _D / 2
· The flow path cross-sectional area when the channel cross-section is semicircular ^{_{S B = π · S C 2}} /8
-Channel cross-sectional area S _B = π · S _C · S _D / 4 when channel cross section is semi-elliptical
Incidentally, the flow path cross-section, in the case of complex shapes, the channel cross-section may be obtained channel cross-sectional area S _B by summing subdividing above basic shapes.

  Thereby, even if the vapor chamber is thinned, a necessary condensate flow path can be secured, heat transport performance can be obtained, and the wall 15b is sufficient for repeated freezing and melting of the working fluid. It can have excellent strength and has excellent durability.

Here, when considering the durability of the wall, the reason for defining the width of the wall with respect to the channel cross-sectional area as described above will be described. FIG. 17A and FIG. 17B are diagrams for explanation.
Focusing on the z direction (thickness direction) of the vapor chamber, if the thickness of the material that exists in both the thickness direction of the condensate flow path is sufficiently thick relative to the height of the condensate flow path, The product of “material tensile strength (property value)” and “wall cross-sectional area” is “pressure generated in the z-direction due to volume expansion when frozen” and “in-plane direction area per wall (figure When the product is smaller than the product of “the area of the portion D ₁₀ indicated by light ink in FIG. 16”, the wall breaks. This in case be considered only z direction force as indicated by the arrow Z ₁ in FIG. 17 (a).

In practice, however, the pressure generated is not constant because there is a process of repeated freezing and thawing of the working fluid and because the shape is not simple and freezing and thawing do not occur in the same direction. Further, since the material constituting the vapor chamber is required to have high thermal conductivity, a relatively soft material is applied, and plastic deformation occurs little by little during repeated freezing and thawing.
Various elements overlap resulting in the wall, such as described above, extends in the thickness direction, receives the force of being compressed in the thinned direction as indicated by arrow y ₁ in FIG. 17 (a), When exaggerated, the shape changes as shown in FIG.
For this reason, when considering the durability of the wall, it is necessary to consider not only the height of the condensate flow path but also the entire cross section of the flow path in consideration of both the height and the width direction. Stipulated.

In particular, as shown by D ₁ in FIG. 16, in the site where the Ekiren communication opening 15c and the Ekiren communication opening portion 15c and the condensate flow path 3 is communicated, the heat transport by the distributor or the like of the condensed liquid as described above There are advantages from the point of view. However, on the other hand, condensate tends to accumulate here when the vapor chamber is not in operation, and when the working fluid expands due to freezing, it becomes a part where a large force is applied to separate the first sheet and the second sheet. .

  In this embodiment, the wall 15b does not break even when the force described above is repeatedly applied.

  FIGS. 18 to 20 are diagrams for explaining a vapor chamber according to a modification.

FIG. 18 is a view from the same viewpoint as FIG. 16, and in the longitudinal direction of the wall 15 b (longitudinal direction of the condensate flow path 3), the position of the liquid communication opening 15 c provided in the adjacent wall 15 b is different. This is an example of arrangement.
According to such a liquid communication opening 15c, when viewed from the working fluid flowing in the condensate flow path 3, the liquid communication opening 15c does not appear at the same time on both side walls, and the liquid communication opening 15 appears. Since the wall 15b exists on one side, a capillary force can be continuously obtained in the longitudinal direction of the condensate flow path 3. Thereby, the movement of the condensate is promoted, and the working fluid can be more smoothly circulated.
The amount on the other hand, in this embodiment, since the capillary force becomes stronger than the example of FIG. 16 in the vicinity of Ekiren communication opening portion 15c as shown in D ₂ in FIG. 18, the condensate during non-operation of the vapor chamber is accumulated Will increase. Then, when the condensate freezes and the volume increases in this state, the force acts in the direction of separating the first sheet and the second sheet with a stronger force, and acts in the direction of destroying the wall 15b. However, according to the present embodiment, by providing the structure as described above, the wall 15b does not break even when the condensate is repeatedly frozen and melted and the above force is repeatedly applied.
That is, even if a structure that further increases the heat transport capability is applied to a thin vapor chamber, the durability is excellent.

FIG. 19 is a view from the same viewpoint as FIG. 16, and in the longitudinal direction of the wall 15b (longitudinal direction of the condensate flow path 3), following the example described in FIG. 6 (a) to FIG. 6 (c), This is an example in which the width of the wall 15b is the smallest at the end where the liquid communication opening 15c is formed.
According to such a liquid communication opening 15c, the flow resistance when passing through the liquid communication opening 15c is suppressed, so that the working fluid can easily move to the adjacent condensate flow path 3, thereby condensing liquid. This facilitates the smooth movement of the working fluid.
On the other hand, in this embodiment, when the condensate collected around the liquid communication opening 15c freezes to increase its volume and a force acts in the direction separating the first sheet and the second sheet, D _{3 in} FIG. The stress is concentrated on the narrow end of the wall 15b as shown in FIG.
However, according to this embodiment, by providing the above-described structure, the wall 15b does not break even when the above-described force is repeatedly applied by repeatedly freezing and melting the condensate.
That is, even if a structure that further increases the heat transport capability is applied to a thin vapor chamber, the durability is excellent.

FIG. 20 is a view from the same viewpoint as FIG. 14, and is an example in which a minute inner surface groove 3 a is formed on the flow path surface of the condensate flow path 3 (the surface of the wall 15 b).
According to such a condensate flow path 3, since the condensate enters the minute inner groove 3a and receives a strong capillary force, the condensate easily moves, the condensate moves more easily, and the working fluid becomes smoother. Reflux is possible.
However, on the other hand, when the vapor chamber is not in operation, the condensate tends to accumulate in the minute inner surface groove 3a due to strong capillary force. It becomes power.
However, according to the present embodiment, by providing the structure as described above, the wall 15b does not break even when the condensate is repeatedly frozen and melted and force is repeatedly applied.
That is, even if a structure that further increases the heat transport capability is applied to a thin vapor chamber, the durability is excellent.
Incidentally, as also shown in FIG. 20, the width S _A wall 15b as described _above, when considering the channel width S _C does not consider the inner surface groove 3a, the distance between the opening edge of the inner surface groove 3a, the wall 15b the width _{S a} and the channel width _{S C.}

The cross-sectional shape and cross-sectional area of the inner surface groove 3a are not particularly limited as long as it is a groove provided on the inner surface of the condensate flow path 3. However, it is preferable that the inner surface groove has a longitudinal direction containing a directional component parallel to the direction in which the condensate channel 3 extends, and extends at least longer than twice the opening width δ of the inner surface groove 3a. This has a more remarkable effect as a groove for increasing the capillary force.
The opening width δ of the inner surface groove 3a is preferably less than 10 μm. Thereby, high capillary force is securable. The depth γ of the inner groove is preferably less than 10 μm.

The vapor chamber as described above can be manufactured, for example, as follows.
Liquid channel grooves 14a, 15a, vapor channel grooves 16, 26, and vapor channel communication grooves 17, 27 are formed by half etching on the metal sheet having the outer peripheral shape of the first sheet 10 and the second sheet 20. To do. Here, half-etching means that a material is removed by etching halfway in the thickness direction without penetrating the thickness direction by etching to form grooves and depressions.
By such etching, the wall 14b as shown in FIGS. 6A to 6C, the shape of the wall 15b according to this, and the minute inner surface groove 3a shown in FIG. 20 can be easily formed.

Next, the inner surfaces 10a and 20a of the first sheet 10 and the second sheet 20 are overlapped so as to face each other, positioned using holes 13a and 23a as positioning means, and temporarily fixed. The method of temporary fixing is not particularly limited, and examples thereof include resistance welding, ultrasonic welding, and adhesion using an adhesive.
Then, diffusion bonding is performed after temporary fixing, and the first sheet 10 and the second sheet 20 are permanently bonded. In addition, you may join by brazing instead of diffusion bonding.

  After joining, evacuation is performed from the formed injection flow path 5, and the sealed space 2 is decompressed. Thereafter, the working fluid is injected from the injection flow path 5 into the decompressed sealed space 2, and the working fluid is put into the sealed space 2. Then, the injection flow path 5 is closed by utilizing melting or caulking with respect to the injection portions 12 and 22. As a result, the working fluid is stably held inside the sealed space 2.

  Next, the operation when the vapor chamber 1 is activated will be described. FIG. 21 schematically illustrates a state in which the vapor chamber 1 is disposed inside a portable terminal 40 that is one form of the electronic apparatus. Here, since the vapor chamber 1 is disposed inside the casing 41 of the portable terminal 40, it is represented by a dotted line. Such a portable terminal 40 includes a housing 41 that contains various electronic components, and a display unit 42 that is exposed so that an image can be seen through the opening of the housing 41. As one of these electronic components, an electronic component 30 to be cooled by the vapor chamber 1 is disposed in the housing 41.

The vapor chamber 1 is installed in a housing of a portable terminal or the like, and is attached to an electronic component 30 that is an object to be cooled such as a CPU. The electronic component 30 is attached to the outer surface 10b or the outer surface 20b of the vapor chamber 1 directly or via an adhesive, sheet, tape, or the like having high thermal conductivity. The position at which the electronic component 30 is attached to the outer surface 10b or the outer surface 20b is not particularly limited, and is appropriately set depending on the relationship with the arrangement of other members in the portable terminal or the like. In this embodiment, as indicated by a dotted line in FIG. 1A, the electronic component 30 that is a heat source to be cooled is arranged in the center of the main body 11 in the xy direction on the outer surface 10 b of the first sheet 10. Therefore, in FIG. 1A, the electronic component 30 is represented by a dotted line because it is a blind spot and cannot be seen.
FIG. 22 is a diagram for explaining the flow of the working fluid. For ease of explanation, the second sheet 20 is omitted in this figure, and the inner surface 10a of the first sheet 10 is shown so that it can be seen.

  When the electronic component 30 generates heat, the heat is transmitted through the first sheet 10 by heat conduction, and the condensate present at a position close to the electronic component 30 in the sealed space 2 receives heat. The condensate that has received this heat absorbs the heat and evaporates. Thereby, the electronic component 30 is cooled.

The vaporized working fluid becomes steam and flows and moves in the steam flow path 4 as indicated by a solid straight arrow in FIG. Since this flow is generated in a direction away from the electronic component 30, the vapor moves in a direction away from the electronic component 30.
The vapor in the vapor flow path 4 leaves the electronic component 30 that is a heat source, moves to the outer peripheral portion of the vapor chamber 1 having a relatively low temperature, and sequentially heats the first sheet 10 and the second sheet 20 during the movement. It is cooled while being taken away. The first sheet 10 and the second sheet 20 that have taken heat from the steam conduct heat to the casing of the portable terminal device that is in contact with the outer surfaces 10b and 20b, and finally the heat is released to the outside air.

  The working fluid deprived of heat while moving through the steam flow path 4 is condensed and liquefied. This condensate adheres to the wall surface of the steam channel 4. On the other hand, since steam continuously flows through the steam flow path 4, the condensate moves from the liquid communication opening or the like to the condensate flow path 3 so as to be pushed by the steam. Since the condensate flow path 3 of this embodiment includes the liquid communication openings 14c and 15c, the condensate is distributed to the plurality of condensate flow paths 3 through the liquid communication openings 14c and 15c.

  The condensate that has entered the condensate flow path 3 approaches the electronic component 30 that is a heat source, as indicated by a dotted straight arrow in FIG. 22, due to capillary action by the condensate flow path and pressing from the steam. Moving. And it repeats the above by vaporizing with the heat from the electronic component 30 which is a heat source again.

  As described above, according to the vapor chamber 1, the reflux of the condensate is good with a high capillary force in the condensate flow path, and the amount of heat transport can be increased.

DESCRIPTION OF SYMBOLS 1 Vapor chamber 2 Sealed space 3 Condensate flow path 4 Vapor flow path 10 1st sheet | seat 10a Inner surface 10b Outer surface 10c Side surface 11 Main body 12 Injection | pouring part 13 Outer periphery junction part 14 Outer periphery liquid channel part 14a Liquid channel groove | channel 14c Liquid communication opening part DESCRIPTION OF SYMBOLS 15 Inner liquid flow path part 15a Liquid flow path groove 15c Liquid communication opening 16 Steam flow path groove 17 Steam flow path communication groove 20 2nd sheet | seat 20a Inner surface 20b Outer surface 20c Side surface 21 Main body 22 Injection | pouring part 23 Outer periphery junction part 24 Outer periphery liquid flow Road portion 25 Inner liquid passage portion 26 Steam passage groove 27 Steam passage communication groove

Claims (7)

A vapor chamber in which a sealed space is formed between two sheets, and a working fluid is sealed in the space;
A plurality of flow paths through which the working fluid flows are formed in the sealed space, and a wall is provided between the adjacent flow paths so as to connect the two sheets.
The wall width S _A is 20 μm or more and 300 μm or less, and S _A / S _B, which is related to the cross-sectional area S _B (μm ² ) of the cross section of the flow path, is 0.005 (μm ⁻¹ ) or more. A vapor chamber which is 0.04 (μm ⁻¹ ) or less. The flow path has a plurality of condensate flow paths through which the liquid condensed from the working fluid flows, and a vapor flow path through which the vapors vaporized from the working fluid flow,
The vapor chamber according to claim 1, wherein the wall is a wall formed between adjacent condensate flow paths.   The vapor chamber according to claim 2, wherein a width of the condensate flow path is 10 μm or more and 300 μm or less.   The vapor chamber according to claim 2 or 3, wherein a groove is formed on a surface of the condensate flow path.   The vapor chamber according to any one of claims 1 to 4, wherein the wall has a plurality of openings that communicate adjacent flow paths.   The vapor chamber according to any one of claims 1 to 5, wherein the openings are provided so that positions thereof are different in directions in which the flow paths extend in adjacent walls. A housing,
An electronic component disposed inside the housing;
An electronic device comprising: the vapor chamber according to any one of claims 1 to 6, which is disposed directly or in contact with the electronic component via another member.

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