Vapor chamber, electronic device, and method for manufacturing vapor chamber

Abstract

To provide a vapor chamber which can inhibit deformation even if a thickness is reduced.SOLUTION: In a vapor chamber, a sealed space is formed between a plurality of sheets and a working fluid is enclosed in the sealed space. The sealed space includes: a condensate liquid passage in which a working fluid moves in a state of a condensate liquid; and a steam passage in which the working fluid moves in a state of steam and the condensate liquid. The vapor chamber has: an inner layer located at the inner side in a thickness direction of the vapor chamber and forming the sealed space; and an outer layer which is located at the outer side relative to the inner layer in the thickness direction of the vapor chamber. A side surface of the vapor chamber is covered with the outer layer. The inner layer is exposed at a portion, in which a heat source is disposed, of the vapor chamber. An upper yield point or 0.2% proof stress of a material forming the outer layer is larger than an upper yield point or 0.2% proof stress of a material forming the inner layer.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vapor chamber in which a working fluid sealed in a sealed space moves and transfers heat. [Background technology]

[0002] Electronic devices such as personal computers and mobile devices such as mobile phones and tablet computers use electronic components such as CPUs (Central Processing Units). As the amount of heat generated by these electronic components tends to increase with improvements in information processing capabilities, technology to cool them has become important. Heat pipes are a well-known cooling method, in which a working fluid sealed inside the pipe transports and diffuses heat from a heat source to another location by utilizing the phase change of the fluid, thereby cooling the heat source.

[0003] Meanwhile, in recent years, these electronic devices have become significantly thinner, creating a need for cooling means thinner than conventional heat pipes. Vapor chambers have been proposed to address this need. Vapor chambers, sometimes called sheet-type heat pipes, are devices that apply the heat transport concept of heat pipes to flat plate-shaped components. In other words, vapor chambers contain a working fluid sealed between opposing flat plates, and utilize the phase change of this working fluid to transport and diffuse heat from a heat source, thereby cooling the heat source.

[0004] For example, Patent Document 1 discloses a vapor chamber (flat heat pipe) in which a cavity is formed by two opposing plate-shaped members, a working fluid is sealed in this cavity, and a wick structure is provided. Furthermore, in this vapor chamber, at least one of the plate-shaped members is formed from a composite material, and the metal member on the cavity side of this composite material has a thermal conductivity of 200 W / m·K or more, and the outer metal member has a thermal conductivity of 100 W / m·K or less. This is said to ensure proper heat transfer when joining the two plate-shaped members by welding, prevent distortion, and create a vapor chamber with high flatness. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-50713 Summary of the Invention [Problem to be solved by the invention]

[0006] As mentioned above, electronic devices have become thinner in recent years, and this has led to a demand for thinner and smaller vapor chambers as well. Because the materials used in such thinner and smaller vapor chambers are also thinner, the vapor chambers are prone to deformation due to external impacts, expansion caused by solidification of the working fluid due to cryogenic freezing, and vapor pressure during operation. Therefore, further research was needed into ways to prevent deformation.

[0007] In view of the above, an object of the present invention is to provide a vapor chamber that can suppress deformation even when made thin, an electronic device equipped with such a vapor chamber, and a method for manufacturing such a vapor chamber. [Means for solving the problem]

[0008] The present application discloses a vapor chamber in which a sealed space is formed between a plurality of sheets and a working fluid is sealed in the sealed space, the sealed space being provided with a condensate flow path which is a flow path through which the working fluid moves in a condensed liquid state, and a steam flow path through which the working fluid moves in a vapor and condensed liquid state, the vapor chamber having an inner layer which is located inside in the thickness direction of the vapor chamber and forms the sealed space, and an outer layer which is located outside the inner layer in the thickness direction of the vapor chamber, the side surfaces of the vapor chamber being covered by the outer layer, the inner layer being exposed in a portion where a heat source of the vapor chamber is located, and the upper yield point or 0.2% yield strength of the material constituting the outer layer is greater than the upper yield point or 0.2% yield strength of the material constituting the inner layer.

[0009] The present application also discloses a vapor chamber in which a sealed space is formed between multiple sheets and a working fluid is sealed in the sealed space, the sealed space being provided with a condensate flow path which is a flow path through which the working fluid moves in a condensed liquid state and a steam flow path through which the working fluid moves in a vapor and condensed liquid state, the vapor chamber having an inner layer which is a layer that forms the sealed space and is located inside in the thickness direction of the vapor chamber, and an outer layer which is located outside the inner layer in the thickness direction of the vapor chamber, the side surfaces of the vapor chamber are covered by the outer layer and the inner layer is exposed at the joints of the multiple sheets on the side surfaces, and the upper yield point or 0.2% yield strength of the material that makes up the outer layer is greater than the upper yield point or 0.2% yield strength of the material that makes up the inner layer.

[0010] The present application also discloses a vapor chamber in which a sealed space is formed between a plurality of sheets and a working fluid is sealed in the sealed space, the sealed space being provided with a condensate flow path which is a flow path through which the working fluid moves in a condensed liquid state and a steam flow path through which the working fluid moves in a vapor and condensed liquid state, the vapor chamber having an inner layer which is located inside in the thickness direction of the vapor chamber and forms the sealed space, and an outer layer which is located outside the inner layer in the thickness direction of the vapor chamber, the entire side surface of the vapor chamber being covered by the outer layer, and the upper yield point or 0.2% yield strength of the material constituting the outer layer is greater than the upper yield point or 0.2% yield strength of the material constituting the inner layer.

[0011] In the vapor chamber, the outer layer may be a plated layer.

[0012] The present application also discloses an electronic device comprising a housing, an electronic component arranged inside the housing, and the vapor chamber arranged in direct contact with the electronic component or via another member. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a vapor chamber that can suppress deformation even when made thin. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1(a) is a perspective view of the vapor chamber 1, and FIG. 1(b) is an exploded perspective view of the vapor chamber 1. FIG. [Figure 2] FIG. 2(a) is a perspective view of the first sheet 10, and FIG. 2(b) is a plan view of the first sheet 10. As shown in FIG. [Figure 3] FIG. 3 is a cross section of the first sheet 10. [Figure 4] 4(a) and 4(b) are other cross-sectional views of the first sheet 10. FIG. [Figure 5] FIG. 5 is a partially enlarged plan view of the outer peripheral liquid flow path section 14. As shown in FIG. [Figure 6] FIG. 6 is a partially enlarged plan view of another example of the outer peripheral liquid flow path section 14. In FIG. [Figure 7] 7(a) is a cross section focusing on the inner liquid flow path section 15, and FIG. 7(b) is a partially enlarged plan view of the inner liquid flow path section 15. [Figure 8] FIG. 8( a ) is a perspective view of the second sheet 20 , and FIG. 8( b ) is a plan view of the second sheet 20 . [Figure 9] FIG. 9 is a cross section of the second sheet 20. [Figure 10] FIG. 10 shows another cross section of the second sheet 20. [Figure 11] FIG. 11 is a cross section of the vapor chamber 1. [Figure 12] FIG. 12 is an enlarged view of a part of FIG. [Figure 13] FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG. 1(a). [Figure 14] FIG. 14 is a perspective view illustrating the electronic device 40. As shown in FIG. [Figure 15] FIG. 15 is a diagram illustrating the operation of the vapor chamber 1. [Figure 16] FIG. 16 is a diagram for explaining the vapor chamber 101, and is an enlarged view of a part of the cross section of the vapor chamber 101. [Figure 17] FIG. 17 is a perspective view of the vapor chamber 201. [Figure 18] FIG. 18 is a cross section of the vapor chamber 201. [Figure 19] FIG. 19 is a cross section of the vapor chamber 201'. [Figure 20] FIG. 20 is a perspective view of the vapor chamber 301. [Figure 21] FIG. 21 is a perspective view of the vapor chamber 401. As shown in FIG. [Figure 22] FIG. 22 is an exploded perspective view of the vapor chamber 401. [Figure 23]FIG. 23(a) is a view of the third sheet 430 seen from one side, and FIG. 23(b) is a view of the third sheet 430 seen from the other side. [Figure 24] FIG. 24 is a cross section of the third sheet 430. [Figure 25] FIG. 25 shows another cross section of the third sheet 430. [Figure 26] FIG. 26 is a cross section of the vapor chamber 401. [Figure 27] FIG. 27 is an enlarged view of a part of FIG. [Figure 28] FIG. 28 is another cross-section of the vapor chamber 401. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will be described below based on the embodiments shown in the drawings. However, the present invention is not limited to these embodiments. In the drawings shown below, the size and proportions of components may be changed or exaggerated for clarity. Furthermore, for clarity, illustrations of parts unnecessary for explanation and repeated reference numerals may be omitted.

[0016] Figure 1(a) shows a perspective view of the exterior of the vapor chamber 1 according to the first embodiment, and Figure 1(b) shows an exploded perspective view of the vapor chamber 1. For convenience, these figures and the figures shown below also show arrows (x, y, z) that indicate mutually orthogonal directions. Here, the xy in-plane direction is the direction along the plate surface of the flat vapor chamber 1, and the z direction is the thickness direction.

[0017] 1(a) and 1(b), the vapor chamber 1 of this embodiment has a first sheet 10 and a second sheet 20. As will be described later, the first sheet 10 and the second sheet 20 are stacked and joined (by diffusion bonding, brazing, etc.) to form a sealed space 2 between the first sheet 10 and the second sheet 20 (see, for example, FIG. 11), and a working fluid is sealed in this sealed space 2.

[0018] In this embodiment, the first sheet 10 is a sheet-like member as a whole. Fig. 2(a) shows a perspective view of the first sheet 10 seen from the inner surface 10a side, and Fig. 2(b) shows a plan view of the first sheet 10 seen from the inner surface 10a side. Fig. 3 shows a cross section of the first sheet 10 when cut along III-III in Fig. 2(b). The first sheet 10 has an inner surface 10a, an outer surface 10b opposite the inner surface 10a, and a side surface 10c that spans the inner surface 10a and the outer surface 10b to form a thickness, and a pattern for a flow path through which the working fluid moves is formed on the inner surface 10a side. As will be described later, the inner surface 10a of the first sheet 10 and the inner surface 20a of the second sheet 20 are overlapped so as to face each other, thereby forming the sealed space 2.

[0019] In this embodiment, the first sheet 10 is configured to have an inner layer 10d made of a material that forms the inner surface 10a, and an outer layer 10e made of a material that forms the outer surface 10b and the side surface 10c. That is, the first sheet 10 is configured by laminating multiple layers, one of which forms the inner surface 10a, and the other layers form the outer surface 10b and the side surface 10c.

[0020] Here, the inner layer 10d has a pattern formed on the inner surface 10a as described above, which allows the working fluid to move. Because the inner layer 10d comes into direct contact with the working fluid, it is preferable that the inner layer 10d be made of a material that is chemically stable with respect to the working fluid and has high thermal conductivity. For example, copper and copper alloys can be used. In particular, the use of copper and copper alloys improves heat transport capacity and facilitates the fabrication of a vapor chamber by etching and diffusion bonding, as described below.

[0021] On the other hand, the outer layer 10e is made of a material with a higher strength than the inner layer 10d in order to increase the strength of the vapor chamber. Specifically, the 0.2% proof stress or upper yield point of the outer layer 10e is preferably greater than the 0.2% proof stress or upper yield point of the inner layer 10d. In particular, when copper or a copper alloy is used for the inner layer 10d, the 0.2% proof stress is significantly reduced when the first sheet 10 and the second sheet 20 are joined by diffusion bonding, brazing, or the like. Therefore, the 0.2% proof stress of the outer layer 10e is preferably 100 MPa or more, and more preferably 200 MPa or more. This allows the vapor chamber to be made thinner, preventing deformation or damage to the vapor chamber even when subjected to forces such as external impact, expansion due to solidification of the working fluid caused by low-temperature freezing, and vapor pressure during operation. Furthermore, since the outer layer 10e can improve the strength of the vapor chamber in this way, the pattern through which the working fluid moves formed in the inner layer 10d can be designed with a focus on thermal performance rather than improving strength, which can be said to be advantageous from the standpoint of thermal performance as well.

[0022] On the other hand, the material constituting the outer layer 10e is not particularly limited, but from the viewpoint of heat diffusion, it is preferable that the material has a high thermal conductivity, preferably 10 W / m K or more. From this viewpoint, examples of the material constituting the outer layer 10e include stainless steel, nickel, and nickel alloys. Alternatively, composite materials containing fine particles of diamond, alumina, silicon carbide, or the like may be used.

[0023] The thickness of the outer layer 10e is not particularly limited, but is preferably 5 μm to 30 μm. If it is thinner than 5 μm, the effect of suppressing deformation may be reduced, and if it is thicker than 30 μm, heat transfer from the vapor chamber to the outside may be hindered.

[0024] Furthermore, the thickness of the outer layer 10e does not need to be constant, and the thickness may vary depending on the location, for example, by forming it thicker in areas where high strength is required, or by making the outer layer thicker in areas where high thermal resistance is required from the perspective of heat diffusion, or by making it thinner in areas where low thermal resistance is required. Furthermore, the outer surface 10b and the side surface 10c do not all need to be made of the outer layer 10e, and the outer surface 10b may be configured by exposing the inner layer 10d to a portion thereof. This embodiment will be described later with an example.

[0025] The thickness of the first sheet 10 described above is not particularly limited, but is preferably 0.1 mm or more and 1.0 mm or less, and more preferably 0.1 mm or more and 0.2 mm or less. This increases the number of situations in which it can be used as a thin vapor chamber. Furthermore, with the above-described configuration, even such a thin vapor chamber is resistant to deformation and breakage.

[0026] Such a first sheet 10 includes a main body 11 and an injection portion 12. The main body 11 is sheet-shaped and forms a portion through which the working fluid moves, and in this embodiment is a rectangle with arcuate (so-called R) corners in a plan view. The injection portion 12 is a portion where the working fluid is injected into the sealed space 2 (see, for example, FIG. 11) formed by the first sheet 10 and the second sheet 20, and in this embodiment is a sheet-like shape that is rectangular in plan view and protrudes from one side of the main body 11 that is rectangular in plan view. In this embodiment, the injection portion 12 of the first sheet 10 has flat surfaces on both the inner surface 10a side and the outer surface 10b side.

[0027] On the inner surface 10a side of the main body 11, that is, on the inner surface 10a side of the inner layer 10d, a structure for moving the working fluid is formed. Specifically, the structure includes an outer periphery joining portion 13, an outer periphery liquid flow path portion 14, an inner liquid flow path portion 15, a steam flow path groove 16, and a steam flow path connecting groove 17 on the inner surface 10a side of the main body 11.

[0028] The outer peripheral joining portion 13 is a surface formed on the inner surface 10a side of the main body 11 along the outer periphery of the main body 11. This outer peripheral joining portion 13 is overlapped with and joined (by diffusion bonding, brazing, etc.) to the outer peripheral joining portion 23 of the second sheet 20, thereby forming an enclosed space 2 between the first sheet 10 and the second sheet 20, and a working fluid is sealed therein. Figure 2(b) and Figure 3 show A 10 The width of the outer peripheral joint 13 indicated by can be set as needed, but is preferably 0.8 mm or more and 3.0 mm or less. If this width is smaller than 0.8 mm, there is a risk that the joint area will be insufficient if the first sheet and the second sheet are misaligned when they are joined. Furthermore, if this width is larger than 3.0 mm, there is a risk that the internal volume of the sealed space will be small, making it impossible to ensure sufficient steam flow paths and condensate flow paths.

[0029] In addition, holes 13a penetrating in the thickness direction (z direction) are provided at the four corners of the outer peripheral joint portion 13 of the main body 11. These holes function as positioning means when the second sheet 20 is superimposed.

[0030] The peripheral liquid flow path section 14 functions as a liquid flow path section and constitutes part of the condensed liquid flow path 3 (see, for example, FIG. 12), which is a flow path through which the working fluid passes when condensed and liquefied. FIG. 4(a) shows the part indicated by arrow IVa in FIG. 3, and FIG. 4(b) shows a cross section taken along line IVb-IVb in FIG. 2(b). Both figures show the cross-sectional shape of the peripheral liquid flow path section 14. FIG. 5 shows an enlarged plan view of the peripheral liquid flow path section 14 as seen from the direction indicated by arrow V in FIG. 4(a).

[0031] As can be seen from these figures, the peripheral liquid flow path section 14 is formed along the inside of the peripheral joining section 13 on the inner surface 10a of the main body 11, and is provided in a ring shape along the outer periphery of the sealed space 2. The peripheral liquid flow path section 14 also has liquid flow path grooves 14a that are multiple grooves extending parallel to the outer periphery of the main body 11, and the multiple liquid flow path grooves 14a are arranged at intervals in a direction different from the direction in which the liquid flow path grooves 14a extend. Therefore, as can be seen from Figures 4(a) and 4(b), the peripheral liquid flow path section 14 has a cross section in which the liquid flow path grooves 14a, which are recesses, and the walls 14b, which are protrusions between the liquid flow path grooves 14a, are formed in a repeated irregular shape. Here, since the liquid flow path groove 14a is a groove, its cross section has openings at the bottom and at a portion on the opposite side facing the bottom.

[0032] Furthermore, by providing a plurality of liquid flow path grooves 14a in this manner, the depth and width of each liquid flow path groove 14a can be reduced, and the flow path cross-sectional area of ​​the condensate flow path 3 (see, for example, FIG. 12) can be reduced, making it possible to utilize a strong capillary force. On the other hand, by providing a plurality of liquid flow path grooves 14a, the total internal volume of the condensate flow path 3 as a whole can be ensured to be an appropriate size, allowing the condensate to flow at the required flow rate.

[0033] Furthermore, in the outer peripheral liquid flow path section 14, as can be seen from FIG. 5, adjacent liquid flow path grooves 14a are communicated by liquid communication openings 14c provided at intervals in the wall 14b. This promotes equalization of the amount of condensed liquid among the plurality of liquid flow path grooves 14a, allowing the condensed liquid to flow efficiently. Furthermore, the liquid communication opening 14c provided in the wall 14b adjacent to the steam flow path groove 16 that forms the steam flow path 4 communicates the steam flow path 4 with the condensed liquid flow path 3. Therefore, by providing the liquid communication opening 14c, the condensed liquid generated in the steam flow path 4 can be smoothly transferred to the condensed liquid flow path 3, and the steam generated in the condensed liquid flow path 3 can also be smoothly transferred to the steam flow path 4, which also promotes smooth movement of the working fluid.

[0034] In this embodiment, the liquid communication openings 14c are arranged so as to face each other at the same position in the direction in which the liquid flow path groove 14a extends, with the liquid flow path groove 14a sandwiched between the openings, as shown in Fig. 5. However, this is not limited to this, and the liquid communication openings 14c may be arranged at different positions in the direction in which the liquid flow path groove 14a extends, with the liquid flow path groove 14a sandwiched between the openings, as shown in Fig. 6, for example. In other words, in this case, the liquid communication openings 14c are arranged offset from each other. By providing the liquid communication opening 14c in an offset manner in this way, when viewed from the working fluid flowing through the condensate flow path 3, the liquid communication opening 14c does not appear on both sides at the same time, and even when the liquid communication opening 14c appears, there is always a wall 14b on at least one side. Therefore, capillary force can be obtained continuously. From this perspective, by forming the liquid communication opening 14c in an offset manner, the capillary force acting on the working fluid can be maintained high, allowing the condensate to flow smoothly.

[0035] The peripheral liquid flow path section 14 having the above-described configuration preferably further has the following configuration. Figure 2(b), Figure 3, Figure 4(a), Figure 4(b) show B 10 The width of the outer peripheral liquid flow path portion 14 shown in can be set appropriately based on the size of the entire vapor chamber, but is preferably 0.3 mm or more and 2 mm or less. If this width is smaller than 0.3 mm, there is a risk that the amount of liquid flowing on the outer side will be insufficient. Also, if this width exceeds 2 mm, there is a risk that there will not be enough space for the inner condensate flow path and vapor flow path.

[0036] The width of the liquid flow path groove 14a, indicated by C1 in FIG. 4(a) and FIG. 5, is preferably 10 μm or more and 300 μm or less. Furthermore, the depth of the liquid flow path groove 14a, indicated by D in Figures 4(a) and 4(b), is preferably 5 µm or more and 200 µm or less. This allows the capillary force of the liquid flow path, which is necessary for the liquid to flow, to be fully exerted. Here, the depth D of the liquid flow path groove is preferably smaller than the remaining sheet thickness obtained by subtracting the depth D of the groove from the thickness of the first sheet 10. This more reliably prevents the sheet from breaking when the working fluid freezes. From the viewpoint of exerting a stronger capillary force in the flow channel, the aspect ratio (length-to-length ratio) of the flow channel cross section represented by C1 / D is preferably greater than 1.0 or less than 1.0. Among these, from the viewpoint of manufacturing, it is preferable that C1>D, and the aspect ratio is preferably greater than 1.3.

[0037] 4(a) and 5, the width of the wall 14b is preferably 20 μm or more and 300 μm or less. If this width is smaller than 20 μm, the wall 14b will be prone to fracture due to repeated freezing and melting of the working fluid, and if this width is larger than 300 μm, the width of the liquid communication opening 14c will be too large, which may hinder smooth communication of the working fluid with the adjacent condensate flow path 3.

[0038] The size of the liquid communication opening 14c along the direction in which the liquid flow path groove 14a extends, indicated by C3 in FIG. 5, is preferably 20 μm or more and 180 μm or less. Furthermore, the pitch between adjacent liquid communication openings 14c in the direction in which the liquid flow path grooves 14a extend, indicated by C4 in FIG. 5, is preferably 300 μm or more and 2700 μm or less.

[0039] In this embodiment, the cross-sectional shape of the liquid flow path groove 14a is semi-elliptical, but is not limited to this and may be quadrangular such as square, rectangle, or trapezoid, triangular, semicircular, with a semi-circular bottom, or with a semi-elliptical bottom, etc.

[0040] Furthermore, it is preferable that the liquid flow path groove 14a is formed continuously along the edge of the sealed space. That is, it is preferable that the liquid flow path groove 14a extends annularly around the entire circumference without being interrupted by other components. This reduces factors that hinder the movement of condensed liquid, allowing the condensed liquid to move smoothly.

[0041] Returning to Figures 2 and 3, the inner liquid flow path section 15 will now be described. The inner liquid flow path section 15 also functions as a liquid flow path section, and is a portion that constitutes part of the condensed liquid flow path 3 through which the working fluid passes when condensed and liquefied. Figure 7(a) shows the portion indicated by VIIa in Figure 3. This figure also shows the cross-sectional shape of the inner liquid flow path section 15. Figure 7(b) shows an enlarged plan view of the inner liquid flow path section 15 as seen from the direction indicated by arrow VIIb in Figure 7(a).

[0042] As can be seen from these figures, the inner liquid flow path section 15 is formed on the inner surface 10a of the main body 11, inside the ring of the annular outer peripheral liquid flow path section 14. As can be seen from Figures 2(a) and 2(b), the inner liquid flow path section 15 in this embodiment is a straight convex ridge that extends in a direction parallel to the long side (x direction) of the rectangular main body 11 in a plan view, and multiple (three in this embodiment) inner liquid flow path sections 15 are arranged at intervals in a direction parallel to the short side (y direction) and are disposed between the steam flow path grooves 16. Each inner liquid flow path section 15 is formed with a liquid flow path groove 15a, which is a linear groove parallel to the direction in which the inner liquid flow path section 15 extends, and multiple liquid flow path grooves 15a are arranged at predetermined intervals in a direction different from the direction in which the liquid flow path grooves 15a extend. Therefore, as can be seen from Figures 3 and 7(a), in the cross section of the inner liquid flow path section 15, the liquid flow path grooves 15a, which are recesses, and the walls 15b, which are protrusions between the liquid flow path grooves 15a, are formed in a repeated irregular pattern. Here, since the liquid flow path groove 15a is a groove, its cross section has openings at the bottom and at a portion on the opposite side facing the bottom.

[0043] By providing a plurality of liquid flow path grooves 15a in this way, the depth and width of each liquid flow path groove 15a can be reduced, and the flow path cross-sectional area of ​​the condensate flow path 3 (see, for example, FIG. 12) can be reduced, making it possible to utilize a large capillary force. On the other hand, by providing a plurality of liquid flow path grooves 15a, the total internal volume of the condensate flow path 3 as a whole can be ensured to be an appropriate size, allowing the condensate to flow at a required flow rate.

[0044] Furthermore, as can be seen from FIG. 7( b), in the inner liquid flow path section 15, similar to the example of the outer peripheral liquid flow path section 14, adjacent liquid flow path grooves 15a are connected by liquid communication openings 15c provided at intervals in the wall 15b, in the same manner as in FIG. 5. This promotes equalization of the amount of condensed liquid among the plurality of liquid flow path grooves 15a, allowing the condensed liquid to flow efficiently. Furthermore, the liquid communication opening 15c provided in the wall 15b adjacent to the steam flow path groove 16 that forms the steam flow path 4 connects the steam flow path 4 and the condensed liquid flow path 3. Therefore, as will be described later, by providing the liquid communication opening 15c, the condensed liquid generated in the steam flow path 4 can be smoothly transferred to the condensed liquid flow path 3, and the steam generated in the condensed liquid flow path can also be smoothly transferred to the steam flow path 4, thereby promoting smooth movement of the working fluid.

[0045] Also in the inner liquid flow path section 15, following the example of FIG. 6, the liquid communication openings 15c may be arranged at different positions in the direction in which the liquid flow path groove 15a extends, sandwiching the groove. By providing the liquid communication opening 15c in an offset manner in this way, when viewed from the working fluid flowing through the condensate flow path 3, the liquid communication opening 15c does not appear on both sides at the same time, and even when the liquid communication opening 15c appears, there is always a wall 15b on at least one side. Therefore, capillary force can be obtained continuously. From this perspective, by forming the liquid communication opening 15c in an offset manner, the capillary force acting on the working fluid can be maintained at a high level, allowing the working fluid to move more smoothly.

[0046] The inner liquid flow path section 15 having the above-described configuration preferably further has the following configuration. Figures 2(b), 3, and 7(a) show E 10 The width of the inner liquid flow path section 15 indicated by is preferably 100 μm or more and 2000 μm or less. The pitch between the plurality of inner liquid flow path sections 15 is preferably 200 μm or more and 4000 μm or less. This sufficiently reduces the flow path resistance of the steam flow path, and allows for a good balance between the movement of the working fluid in the steam flow path and the movement of the working fluid due to the action of capillary force in the condensate flow path.

[0047] The width of the liquid flow path groove 15a, indicated by F1 in FIGS. 7(a) and 7(b), is preferably 10 μm or more and 300 μm or less. Furthermore, the depth of the groove indicated by G in FIG. 7(a) is preferably 5 μm or more and 200 μm or less. This allows the capillary force of the condensate flow path, which is necessary for the movement of condensate, to be fully exerted. Here, the groove depth G is preferably smaller than the remaining sheet thickness obtained by subtracting the groove depth G from the thickness of the first sheet 10. This more reliably prevents the sheet from breaking when the working fluid freezes. From the viewpoint of exerting a stronger capillary force in the flow channel, the aspect ratio (length-to-length ratio) of the flow channel cross section, expressed as F1 / G, is preferably greater than 1.0 or less than 1.0. Among these, from the viewpoint of manufacturing, it is preferable that F1>G, and the aspect ratio is preferably greater than 1.3.

[0048] 7(a) and 7(b), the width of the wall 15b, indicated by F2, is preferably 20 μm or more and 300 μm or less. If this width is smaller than 20 μm, the wall 15b will be prone to fracture due to repeated freezing and melting of the working fluid, and if this width is larger than 300 μm, the width of the liquid communication opening 15c will be too large, which may hinder smooth communication between the condensate flow paths 3.

[0049] The size of the liquid communication opening 15c along the direction in which the liquid flow path groove 15a extends, indicated by F3 in FIG. 7(b), is preferably 20 μm or more and 180 μm or less. Furthermore, the pitch between adjacent liquid communication openings 15c in the direction in which the liquid flow path groove 15a extends, indicated by F4 in FIG. 7(b), is preferably 300 μm or more and 2700 μm or less.

[0050] In addition, in this embodiment, the cross-sectional shape of the liquid flow path groove 15a is semi-elliptical, but is not limited to this and may be quadrangular such as square, rectangle, or trapezoid, triangular, semicircular, or may have a semi-circular bottom or a semi-elliptical bottom.

[0051] Next, the steam flow channel groove 16 will be described. The steam flow channel groove 16 is a portion through which the working fluid in the vapor and condensed liquid states moves, and constitutes a part of the steam flow channel 4. Fig. 2(b) shows the shape of the steam flow channel groove 16 in a plan view, and Fig. 3 shows the cross-sectional shape of the steam flow channel groove 16.

[0052] As can be seen from these figures, the steam flow path grooves 16 are linear grooves formed on the inner surface 10a of the main body 11, inside the ring of the annular outer peripheral liquid flow path section 14. More specifically, the steam flow path grooves 16 in this embodiment are formed between adjacent inner liquid flow path sections 15 and between the outer peripheral liquid flow path section 14 and the inner liquid flow path section 15, and are rectangular in plan view of the main body 11, extending in a direction parallel to the long sides (x direction). A plurality of steam flow path grooves 16 (four in this embodiment) are arranged in a direction parallel to the short sides (y direction). Therefore, as can be seen from FIG. 3, the first sheet 10 has a shape in which projections and depressions are repeated in the y direction, with the outer peripheral liquid flow path section 14 and the inner liquid flow path section 15 as protrusions and the steam flow path grooves 16 as recesses. Here, since the steam flow channel groove 16 is a groove, its cross-sectional shape has openings at the bottom and at a portion on the opposite side facing the bottom.

[0053] The steam flow path groove 16 may be configured so that, when combined with the steam flow path groove 26 of the second sheet 20 to form the steam flow path 4, the working fluid moves through the steam flow path 4. Therefore, it is preferable that the steam flow path groove 16 further has the following configuration. H in Fig. 2(b) and Fig. 3 10The width of the vapor flow channel groove 16 indicated by is formed to be at least larger than the widths C1 and F1 of the liquid flow channel grooves 14a and 15a, and is preferably 100 μm or more and 2000 μm or less. On the other hand, the depth of the vapor flow path groove 16 indicated by I10 in FIG. 3 is formed to be at least greater than the depths D and G of the liquid flow path grooves 14a and 15a described above, and is preferably 10 μm or more and 300 μm or less. This allows for stable movement of the working fluid when the steam flow path is formed, and by making the flow path cross-sectional area of ​​the steam flow path groove larger than that of the liquid flow path groove, steam, which has a larger volume than condensed liquid due to the nature of the working fluid, can be moved smoothly.

[0054] Here, the steam flow channel groove 16 is preferably configured so that when combined with the second sheet 20 to form the steam flow channel 4, as will be described later, the steam flow channel 4 has a flat shape in which the width is greater than the height (size in the thickness direction). 10 / I 10 The aspect ratio represented by is preferably 4.0 or more, more preferably 8.0 or more.

[0055] In this embodiment, the cross-sectional shape of the steam flow channel groove 16 is semi-elliptical, but it is not limited to this and may be quadrangular such as square, rectangle, or trapezoid, triangular, semicircular, or may have a circular bottom or a semi-elliptical bottom.

[0056] The steam flow path communication grooves 17 are grooves that connect the multiple steam flow path grooves 16 together and, in combination with the steam flow path communication grooves 27 of the second sheet 20, form flow paths that connect the multiple steam flow paths 4 formed by the steam flow path grooves 16 at their ends. This allows for smooth movement of the working fluid generated in the steam flow paths 4 in the direction in which the inner liquid flow path section 15 extends. This also makes it possible to equalize the working fluid in the steam flow path 4, transport the steam over a wider area, and efficiently utilize the condensate flow path 3 formed by the many liquid flow grooves 14a, 15a.

[0057] As can be seen from Figures 2(a) and 2(b), the steam flow path communication grooves 17 in this embodiment are formed between both ends in the direction in which the inner liquid flow path section 15 extends and both ends in the direction in which the steam flow path grooves 16 extend, and the outer peripheral liquid flow path section 14. Figure 4(b) shows a cross section perpendicular to the communication direction of the steam flow path communication grooves 17. Note that the boundary between the steam flow path communication grooves 17 and the steam flow paths 16 is not necessarily formed by a boundary due to their shape, and therefore, for ease of understanding, the boundary is shown by a dotted line in Figures 2(a) and 2(b).

[0058] The steam flow path communication groove 17 may have any shape as long as it can communicate with the adjacent steam flow path grooves 16, but may have the following configuration, for example. Figure 2(b) and Figure 4(b) show 10 The width of the steam flow path communicating groove 17 indicated by is preferably 100 μm or more and 1000 μm or less. Also, in Fig. 4(b), K 10 The depth of the steam flow path communication groove 17 indicated by is preferably 10 μm or more and 300 μm or less, and among these, the depth I of the steam flow path groove 16 10 This makes manufacturing easier.

[0059] In this embodiment, the cross-sectional shape of the steam flow path communication groove 17 is semi-elliptical, but is not limited to this and may be quadrangular such as square, rectangle, or trapezoid, triangular, semicircular, or with a semi-circular bottom or a semi-elliptical bottom, etc.

[0060] Next, the second sheet 20 will be described. In this embodiment, the second sheet 20 is also a sheet-like member as a whole. Fig. 8(a) shows a perspective view of the second sheet 20 as seen from the inner surface 20a side, and Fig. 8(b) shows a plan view of the second sheet 20 as seen from the inner surface 20a side. Fig. 9 shows a cross section of the second sheet 20 when cut along IX-IX in Fig. 8(b). Fig. 10 shows a cross section of the second sheet 20 when cut along XX in Fig. 8(b). The second sheet 20 has an inner surface 20a, an outer surface 20b opposite the inner surface 20a, and a side surface 20c that spans the inner surface 20a and the outer surface 20b to form a thickness, and a pattern that allows the working fluid to move is formed on the inner surface 20a side. As will be described later, the inner surface 20a of this second sheet 20 and the inner surface 10a of the first sheet 10 are overlapped and joined so as to face each other, thereby forming the sealed space 2.

[0061] In this embodiment, the second sheet 20 also has an inner layer 20d made of a material that forms the inner surface 20a, and an outer layer 20e made of a material that forms the outer surface 20b and the side surface 20c. That is, the second sheet 20 is made up of a plurality of laminated layers, one of which forms the inner surface 20a, and the other layers form the outer surface 20b and the side surface 20c.

[0062] Here, the inner layer 20d is formed with a pattern on the inner surface 20a for the working fluid to move, as described above, and is in direct contact with the working fluid. Therefore, it is preferable that the inner layer 20d be made of a material that is chemically stable with respect to the working fluid and has high thermal conductivity. For example, copper and copper alloys can be used for this purpose. In particular, the use of copper and copper alloys improves heat transport capacity and facilitates the fabrication of a vapor chamber by etching and diffusion bonding, as described below.

[0063] On the other hand, the outer layer 20e is made of a material stronger than the inner layer 20d in order to increase the strength of the vapor chamber. Specifically, the 0.2% proof stress or upper yield point of the outer layer 20e is preferably greater than the 0.2% proof stress or upper yield point of the inner layer 20d. In particular, when copper or a copper alloy is used for the inner layer 20d, the 0.2% proof stress is significantly reduced when the first sheet 10 and the second sheet 20 are joined by diffusion bonding, brazing, or the like. Therefore, the 0.2% proof stress of the outer layer 20e is preferably 100 MPa or more, and more preferably 200 MPa or more. This allows the vapor chamber to be made thinner, preventing deformation or damage to the vapor chamber even when subjected to forces such as external impact, expansion due to solidification of the working fluid caused by low-temperature freezing, and vapor pressure during operation. Furthermore, since the outer layer 20e can improve the strength of the vapor chamber, the pattern through which the working fluid moves formed in the inner layer 20d can be designed with a focus on thermal performance rather than improving strength, which can be said to be advantageous from the standpoint of thermal performance as well.

[0064] The material and thickness used for the outer layer 20e can be considered to be similar to those of the outer layer 10e described above.

[0065] The thickness of the second sheet 20 described above is not particularly limited, but is preferably 0.1 mm or more and 1.0 mm or less, and more preferably 0.1 mm or more and 0.2 mm or less. This increases the number of situations in which it can be used as a thin vapor chamber. Furthermore, with the above-described configuration, even such a thin vapor chamber is resistant to deformation and breakage.

[0066] The second sheet 20 includes a main body 21 and an injection portion 22. The main body 21 is a sheet-like portion that forms a portion through which the working fluid moves, and in this embodiment, is a rectangle with arcuate (so-called R) corners in a plan view. Injection portion 22 is a portion where the working fluid is injected into sealed space 2 (see, for example, FIG. 11 ) formed by first sheet 10 and second sheet 20, and in this embodiment is a sheet-like shape that is square in plan view and protrudes from one side of main body 21, which is rectangular in plan view. In this embodiment, injection portion 22 of second sheet 20 has injection groove 22a formed on inner surface 20a side, and communicates from side surface 20c of second sheet 20 to the inside of main body 21 (the portion that will become sealed space 2).

[0067] A structure for moving the working fluid is formed on the inner surface 20a side of the main body 21. Specifically, the inner surface 20a side of the main body 21 is provided with an outer periphery joining portion 23, an outer periphery liquid flow path portion 24, an inner liquid flow path portion 25, a steam flow path groove 26, and a steam flow path connecting groove 27.

[0068] The outer peripheral joining portion 23 is a surface formed on the inner surface 20a side of the main body 21 along the outer periphery of the main body 21. This outer peripheral joining portion 23 is overlapped with and joined (by diffusion bonding, brazing, etc.) to the outer peripheral joining portion 13 of the first sheet 10, thereby forming an enclosed space 2 between the first sheet 10 and the second sheet 20, and a working fluid is sealed therein. Figure 8(b), Figure 9, and Figure 10 show A 20 It is preferable that the width of the outer peripheral joint 23 indicated by is the same as the width A10 of the outer peripheral joint 13 of the main body 11 described above.

[0069] In addition, holes 23a penetrating in the thickness direction (z direction) are provided at the four corners of the outer peripheral joint portion 23 of the main body 21. These holes 23a function as positioning means when the first sheet 10 is superimposed.

[0070] The outer circumferential liquid flow path section 24 functions as a liquid flow path section, and is a portion that constitutes a part of the condensed liquid flow path 3 (see, for example, FIG. 12), which is a flow path through which the working fluid passes when condensed and liquefied.

[0071] The peripheral liquid flow path section 24 is formed along the inside of the peripheral joining section 23 on the inner surface 20a of the main body 21, and is formed in a ring shape along the outer periphery of the sealed space 2. In this embodiment, the peripheral liquid flow path section 24 of the second sheet 20 is a flat surface that is flush with the peripheral joining section 23 before being joined to the first sheet 10, as can be seen from Figures 9 and 10. This closes the openings of at least some of the multiple liquid flow path grooves 14a of the first sheet 10 described above, thereby forming the condensate flow paths 3. Detailed aspects of the combination of the first sheet 10 and the second sheet 20 will be described later. In this way, since the outer peripheral joining portion 23 and the outer peripheral liquid flow path portion 24 are flush with each other in the second sheet 20, there is no structural boundary line that distinguishes them. However, for ease of understanding, the boundary between them is indicated by a dotted line in Figures 8(a) and 8(b).

[0072] The peripheral liquid flow path section 24 preferably has the following configuration. The width B of the outer peripheral liquid flow path portion 24 shown in FIG. 8(b), FIG. 9, and FIG. 20is not particularly limited, and the width B of the outer peripheral liquid flow path portion 14 of the first sheet 10 10 In this embodiment, the width B 10 and width B 20 is the same as. Width B 20 Width B 10 If the diameter is made smaller, the opening of the liquid flow path groove 14a is not blocked by the peripheral liquid flow path section 24 in at least a part of the peripheral liquid flow path section 14 and is open, allowing condensed liquid to easily enter and steam to easily exit, thereby enabling smoother movement of the working fluid.

[0073] Next, a description will be given of the inner liquid flow path section 25. The inner liquid flow path section 25 is also a liquid flow path section, and is one of the parts that constitute the condensed liquid flow path 3.

[0074] 8(a), 8(b), 9, and 10, the inner liquid flow path section 25 is formed on the inner surface 20a of the main body 21, inside the annular ring of the outer peripheral liquid flow path section 24. The inner liquid flow path section 25 in this embodiment is a straight convex ridge that extends in a direction parallel to the long side (x direction) of the rectangular main body 21 in a plan view, and multiple (three in this embodiment) inner liquid flow path sections 25 are arranged between the steam flow path grooves 26 at predetermined intervals in a direction parallel to the short side (y direction). In this embodiment, each inner liquid flow path section 25 is formed so that its surface on the inner surface 20a side is flat before being joined to the first sheet 10. As a result, the openings of at least some of the liquid flow path grooves 15a of the first sheet 10 described above are closed, thereby forming the condensate liquid flow paths 3. When grooves for forming the condensate flow paths 3 are not formed in the inner liquid flow path section 25 as in this embodiment, the thickness of the second sheet 20 is preferably equal to or greater than the depth G (see FIG. 7(a)) of the liquid flow path grooves 15a of the first sheet 10. This makes it possible to prevent breakage (tear) on the second sheet side of the vapor chamber.

[0075] The width E of the inner liquid flow path portion 25 shown in FIG. 8(b) and FIG. 20 is not particularly limited, and the width E of the inner liquid flow path portion 15 of the first sheet 1010 In this embodiment, the width E10 and the width E20 are the same. Width E 20 and width E 10 If the width E is different from the width E, the influence of misalignment during joining can be reduced. 20 Width E 10 If it is made smaller, in at least a part of the inner liquid flow path section 15, the opening of the liquid flow path groove 15a is not blocked by the inner liquid flow path section 25 but is open, making it easier for condensed liquid to enter and for generated steam to escape, thereby allowing the working fluid to move more smoothly.

[0076] Next, the steam flow path groove 26 will be described. The steam flow path groove 26 is a portion through which the working fluid in the vapor state and condensed liquid state moves, and constitutes a part of the steam flow path 4. Fig. 8(b) shows the shape of the steam flow path groove 26 in a plan view, and Fig. 9 shows the cross-sectional shape of the steam flow path groove 26.

[0077] As can be seen from these figures, the steam flow path grooves 26 are linear grooves formed on the inner surface 20a of the main body 21, inside the ring of the annular outer peripheral liquid flow path section 24. More specifically, the steam flow path grooves 26 in this embodiment are formed between adjacent inner liquid flow path sections 25 and between the outer peripheral liquid flow path section 24 and the inner liquid flow path section 25, and are grooves that extend in a direction parallel to the long sides (x direction) of a rectangular shape in a plan view of the main body 21. A plurality of (four in this embodiment) steam flow path grooves 26 are arranged in a direction parallel to the short sides (y direction). Therefore, as can be seen from FIG. 9, the second sheet 20 has a shape in which, in the y direction, protrusions are formed with the outer peripheral liquid flow path section 24 and the inner liquid flow path section 25 as protrusions, and recesses are formed with the steam flow path grooves 26 as recesses, with these protrusions and recesses being repeated. Here, since the steam flow channel groove 26 is a groove, its cross-sectional shape has openings at the bottom and at a portion on the opposite side facing the bottom.

[0078] The steam flow channel grooves 26 are preferably arranged at positions that overlap the steam flow channel grooves 16 of the first sheet 10 in the thickness direction when combined with the first sheet 10. This allows the steam flow channel grooves 16 and 26 to form the steam flow channels 4. H in Fig. 8(b) and Fig. 9 20 The width of the steam flow channel groove 26 shown by is not particularly limited, and the width H of the steam flow channel groove 16 of the first sheet 10 10 In this embodiment, the width H 10 and width H 20 is the same as. Width H 20 and width H 10 If the width H is different from the width H, the influence of misalignment during joining can be reduced. 20 Width H 10 If it is made larger, in at least a part of the inner liquid flow path section 15, the opening of the liquid flow path groove 15a is not blocked by the inner liquid flow path section 25 but is open, making it easier for condensed liquid to enter and steam to exit, thereby allowing for smoother movement of the working fluid. On the other hand, in Figure 9, 20 The depth of the vapor flow channel groove 26 indicated by is preferably 10 μm or more and 300 μm or less.

[0079] Here, the steam flow channel groove 26 is preferably configured so that when combined with the first sheet 10 to form the steam flow channel 4, the width of the steam flow channel 4 is greater than the height (size in the thickness direction). 20 / I 20 The aspect ratio represented by is preferably 4.0 or more, more preferably 8.0 or more.

[0080] In this embodiment, the cross-sectional shape of the steam flow channel groove 26 is semi-elliptical, but it may be quadrangular such as square, rectangle, or trapezoid, triangular, semicircular, or with a semicircular bottom or a semi-elliptical bottom.

[0081] The steam flow path communication grooves 27 are grooves that, in combination with the steam flow path communication grooves 17 of the first sheet 10, form flow paths that communicate the ends of the multiple steam flow paths 4 formed by the steam flow path grooves 26. This allows for a well-balanced movement of the working fluid that occurs in the steam flow paths 4 in the direction in which the inner liquid flow path section 25 extends. Furthermore, the working fluid in the steam flow paths 4 is equalized, steam is transported over a wider area, and many condensate flow paths 3 can be used efficiently, making it possible to more smoothly move the working fluid.

[0082] 8(b) and 10, the steam flow path communication grooves 27 of this embodiment are formed between both ends in the direction in which the inner liquid flow path section 25 extends and both ends in the direction in which the steam flow path grooves 26 extend, and the outer circumferential liquid flow path section 24. Also, Fig. 10 shows a cross section perpendicular to the communication direction of the steam flow path communication grooves 27.

[0083] Figure 8(b) and Figure 10 show J 20 The width of the steam flow path communicating groove 27 shown by is not particularly limited, and the width J of the steam flow path communicating groove 17 of the first sheet 10 10 may be the same as the width J 10 It may be different from the width J 20 Width J 10 When the distance is larger than 1 / 2 mm, the openings of the liquid flow path grooves 14a are positioned to form part of the steam flow path 4 in at least a part of the outer peripheral liquid flow path portion 14 of the first sheet 10, making it easier for condensed liquid to enter and for generated steam to exit, thereby allowing the working fluid to move more smoothly.

[0084] Width J 20 The size of is preferably in the range of 100 μm or more and 1000 μm or less, and K 20 The depth of the vapor flow path communication groove 27 indicated by is preferably 10 μm or more and 300 μm or less.

[0085] In this embodiment, the cross-sectional shape of the steam flow path communication groove 27 is semi-elliptical, but is not limited to this and may be square, rectangular, trapezoidal or other quadrilateral, triangular, semicircular, or with a semi-circular bottom or a semi-elliptical bottom.

[0086] Next, we will explain the structure when the first sheet 10 and the second sheet 20 are combined to form the vapor chamber 1. This explanation will help you better understand the arrangement, size, shape, etc. of each component of the first sheet 10 and the second sheet 20. 11 shows a cross section of the vapor chamber 1 cut in the thickness direction along the y direction indicated by XI-XI in FIG. 1(a). This figure combines the diagram of the first sheet 10 shown in FIG. 3 and the diagram of the second sheet 20 shown in FIG. 9 to show the cross section of the vapor chamber 1 at this location. FIG. 12 shows an enlarged view of the portion indicated by XII in FIG. Figure 13 shows a cross section of the vapor chamber 1 cut in the thickness direction along the x direction indicated by XIII-XIII in Figure 1(a). This figure combines the diagram of the first sheet 10 shown in Figure 4(b) and the diagram of the second sheet 20 shown in Figure 10 to show the cross section of the vapor chamber 1 at this location.

[0087] 1(a), 1(b), and 11 to 13, the first sheet 10 and the second sheet 20 are arranged so as to overlap and are joined to form the vapor chamber 1. 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 20 overlap, and the injection section 12 of the first sheet 10 and the injection section 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 position of the hole 13a of the first sheet 10 with the position of the hole 23a of the second sheet 20.

[0088] With such a laminate of the first sheet 10 and the second sheet 20, the components provided in the main body 11 and the main body 21 are arranged as shown in Figures 11 to 13. Specifically, they are as follows.

[0089] In this embodiment, the outer periphery of the vapor chamber 1 is configured to be covered by the outer layer 10e and the outer layer 20e. As described above, the outer layer 10e and the outer layer 20e are configured from a material with higher strength than the inner layer 10d and the inner layer 20d. Therefore, even if the outer shell of the vapor chamber 1 is strong and the vapor chamber is made thinner, deformation or damage to the vapor chamber can be prevented. In other words, deformation or damage to the vapor chamber can be prevented even when subjected to forces such as external impact, expansion due to solidification of the working fluid caused by low-temperature freezing, and vapor pressure during operation.

[0090] On the other hand, the inner layer 10d and the inner layer 20d can be made of a material with high thermal conductivity, so that the thermal resistance can be kept low. At that time, the outer layer 10e and the outer layer 20e can improve the strength of the vapor chamber, so that the pattern through which the working fluid moves formed in the inner layer 10d and the inner layer 20d can be designed with a focus on thermal performance rather than improving strength, which can be said to be advantageous from the viewpoint of thermal performance as well.

[0091] As described above, the thickness of the outer layer 10e and the outer layer 20e does not need to be constant, and the thickness may vary depending on the region. For example, the thickness may be made thicker in regions requiring high strength than in other regions, or thicker in regions requiring high thermal resistance from the viewpoint of heat diffusion than in other regions, or conversely, thinner in regions requiring low thermal resistance than in other regions.

[0092] In this embodiment, the side surfaces 10c and 20c that form the thickness of the vapor chamber 1 are also covered with the outer layers 10e and 20e, which improves the strength of the side surfaces and more reliably suppresses deformation of the vapor chamber.

[0093] The vapor chamber 1 of this embodiment is particularly effective when it is thin. From this perspective, the thickness of the vapor chamber 1, indicated by L0 in FIGS. 1 and 11, is 1 mm or less, more preferably 0.4 mm or less, and even more preferably 0.2 mm or less. By making the thickness 0.4 mm or less, it is often possible to install the vapor chamber inside the electronic device in which the vapor chamber 1 is installed without processing (e.g., forming a groove) to create a space for the vapor chamber. Furthermore, according to this embodiment, even such a thin vapor chamber maintains thermal performance while being strong and resistant to deformation.

[0094] On the other hand, the inner layer 10d and the inner layer 20d are arranged so that the outer peripheral joining portion 13 of the first sheet 10 and the outer peripheral joining portion 23 of the second sheet 20 overlap with each other, and are joined together by a joining means such as diffusion bonding or brazing. This forms an enclosed space 2 between the first sheet 10 and the second sheet 20.

[0095] The peripheral liquid flow path section 14 of the first sheet 10 and the peripheral liquid flow path section 24 of the second sheet 20 are arranged so as to overlap each other. As a result, the liquid flow path grooves 14a of the peripheral liquid flow path section 14 and the peripheral liquid flow path section 24 form a condensed liquid flow path 3 through which the condensed liquid, which is the working fluid that has been condensed and liquefied, flows. Similarly, the inner liquid flow path section 15, which is a convex rib of the first sheet 10, and the inner liquid flow path section 25, which is a convex rib of the second sheet 20, are arranged to overlap each other. As a result, the liquid flow path grooves 15a of the inner liquid flow path section 15 and the inner liquid flow path section 25 form a condensate flow path 3 through which the condensate flows.

[0096] Here, it is preferable that the cross-sectional shape of the condensate flow path 3 be flattened in accordance with the thinning of the vapor chamber 1. This increases the capillary force, allowing the condensate to move more smoothly, thereby maintaining a high level of heat transport capacity. More specifically, it is preferable that the ratio of width / height of the condensate flow path 3 be greater than 1.0 and not more than 4.0. In this embodiment, the width of the condensate flow path 3 corresponds to the width F1 of the liquid flow path groove 15a, but is preferably 10 μm or more and 300 μm or less. If the width is smaller than 10 μm, the flow path resistance increases, which may result in a decrease in transport capacity. On the other hand, if the width is larger than 300 μm, the capillary force decreases, which may result in a decrease in transport capacity. Furthermore, the height of the condensate flow path 3, which corresponds to the depth G of the liquid flow path groove 15a in this embodiment, is preferably 5 μm or more and 200 μm or less. This allows the capillary force of the condensate flow path, which is necessary for movement, to be fully exerted. Note that this height is preferably less than the thickness (wall thickness) of the first sheet 10 and the second sheet 20 on one side and the other side in the thickness direction (z direction) across the condensate flow path 3. This further prevents the vapor chamber from breaking (rupturing) due to the condensate flow path 3.

[0097] In this embodiment, liquid flow path grooves 14a and 15a are provided only in first sheet 10, and therefore the height of the condensate flow path is based on the depth of liquid flow path grooves 14a and 15a, but this is not limiting and liquid flow path grooves may also be provided in second sheet 20. In this case, the liquid flow path grooves of the first sheet and the second sheet overlap to form the condensate flow path, and the height of the condensate flow path corresponds to the sum of the depths of both liquid flow path grooves.

[0098] As described above, the liquid communication openings 14c and 15c are formed in the condensate flow paths 3. This allows the multiple condensate flow paths 3 to communicate with each other, equalizing the condensate and allowing the condensate to move efficiently. Furthermore, the liquid communication openings 14c and 15c, which are adjacent to the steam flow path 4 and communicate between the steam flow path 4 and the condensate flow path 3, allow the condensate generated in the steam flow path 4 to move smoothly to the condensate flow path 3, and allow the steam generated in the condensate flow path 3 to move smoothly to the steam flow path 4, thereby enabling the working fluid to move quickly.

[0099] Furthermore, the condensate flow path 3 formed by the peripheral liquid flow path sections 14, 24 is preferably formed in a continuous ring shape along the edge of the sealed space 2. That is, the condensate flow path 3 formed by the peripheral liquid flow path sections 14, 24 preferably extends in a ring shape around the entire circumference without being interrupted by other components. This reduces factors that hinder the movement of the condensate, allowing the condensate to move smoothly.

[0100] The opening of the steam flow channel groove 16 in the first sheet 10 and the opening of the steam flow channel groove 26 in the second sheet 20 overlap so as to face each other, forming a flow channel, which becomes the steam flow channel 4. Here, it is preferable that the cross section of the vapor flow path 4 is flattened in accordance with the thinning of the vapor chamber 1. This makes it possible to secure the surface area within the flow path even when the vapor chamber 1 is thinned, and to maintain a high level of heat transport capacity. More specifically, the width W of the vapor flow path 4 shown in FIG. B , height H B In W B / H B is preferably 2.0 or more. From the viewpoint of ensuring even higher heat transport capacity, the ratio is more preferably 4.0 or more.

[0101] As can be seen from FIG. 13, the openings of the steam flow path communication grooves 17 of the first sheet 10 and the openings of the steam flow path communication grooves 27 of the second sheet 20 overlap to face each other, forming a flow path, which connects the ends of the multiple steam flow paths 4 formed by the steam flow path grooves 16 and 26, and provides a flow path for balanced movement of the working fluid.

[0102] Due to the condensate flow paths 3 and vapor flow paths 4 described above, the vapor chamber 1 has a shape in which a plurality of linear condensate flow paths 3 are arranged between two steam flow paths 4. This results in a configuration in which the condensate flow paths 3, through which the condensate mainly flows, and the steam flow paths 4, through which the steam and condensate flow, are separated and alternately arranged, which helps smooth movement of the working fluid.

[0103] The steam flow path 4 and the condensate flow path 3 in the sealed space 2 allow the working fluid in the form of steam and condensate to move in the steam flow path 4, thereby efficiently transferring and diffusing heat. On the other hand, the condensate flow path 3, which is provided separately from the steam flow path 4, allows the condensate to move efficiently by capillary force, making it possible to suppress the occurrence of dryout.

[0104] On the other hand, as shown in Figure 1, the inner surfaces 10a, 20a of the injection parts 12, 22 overlap so as to face each other, and the opening opposite the bottom of the injection groove 22a of the second sheet 20 is blocked by the inner surface 10a of the injection part 12 of the first sheet 10, forming an injection flow path 5 that connects the outside with the sealed space 2 (condensate flow path 3 and steam flow path 4) between the main bodies 11, 21. However, after the working fluid is injected into the sealed space 2 from the injection flow path 5, the injection flow path 5 is closed, so that in the final form of the vapor chamber 1, the sealed space 2 is not in communication with the outside.

[0105] A working fluid is sealed in the sealed space 2 of the vapor chamber 1. The type of working fluid is not particularly limited, but working fluids used in ordinary vapor chambers, such as pure water, ethanol, methanol, and acetone, can be used.

[0106] The vapor chamber as described above can be fabricated, for example, as follows.

[0107] A first embodiment of the method for manufacturing the vapor chamber 1 is as follows. A sheet made solely of the material constituting inner layer 10d and having the outer circumferential shape of first sheet 10, and a sheet made solely of the material constituting inner layer 20d and having the outer circumferential shape of second sheet 20 are prepared. The liquid flow path grooves 14a, liquid flow path grooves 15a, vapor flow path grooves 16, vapor flow path grooves 26, vapor flow path connecting grooves 17, and vapor flow path connecting grooves 27 described above are formed in these sheets by half etching. Here, half etching refers to forming grooves and depressions by removing material by etching partway through the thickness direction without etching completely through the thickness direction.

[0108] Next, an etched sheet having the shape of first sheet 10 made only of the material of inner layer 10d and an etched sheet having the shape of second sheet 20 made only of the material of inner layer 20d are overlapped with inner surfaces 10a and 20a facing each other, and they are positioned using holes 13a and 23a as positioning means, and are temporarily fastened together. The method of temporary fastening is not particularly limited, but examples include resistance welding, ultrasonic welding, and adhesion with an adhesive. After the sheets are temporarily attached, they are then bonded permanently by diffusion bonding. Brazing may also be used instead of diffusion bonding.

[0109] After joining, a vacuum is drawn through the formed injection flow path 5 to reduce the pressure in the sealed space 2. Thereafter, the working fluid is injected into the reduced-pressure sealed space 2 through the injection flow path 5, and the working fluid is placed in the sealed space 2. Then, the injection flow path 5 is closed by melting the injection parts 12 and 22 with a laser or by crimping. This allows the working fluid to be stably held inside the sealed space 2.

[0110] The laminate of the inner layers 10d and 20d, with the working fluid sealed in the sealed space 2, is then plated with the material that will form the outer layers 10e and 20e. The plating may be electrolytic plating or electroless plating. As a result, the outer layers 10e and 20e are formed on the outer peripheries of the inner layers 10d and 20d, thereby obtaining the vapor chamber 1. In this case, the outer layers 10e and 20e are integrated. This allows the outer layers to cover the bonding interface, preventing peeling between the first sheet and the second sheet and leakage of the working fluid from the bonding interface.

[0111] A second embodiment of the method for manufacturing a vapor chamber is as follows. A metal sheet consisting only of the material constituting the inner layer 10d and having the outer peripheral shape of the first sheet 10, and a metal sheet consisting only of the material constituting the inner layer 20d and having the outer peripheral shape of the second sheet 20 are prepared. Then, each metal sheet is plated with a material that forms the outer layers 10e and 20e that form the outer surfaces 10b, 20b, side surfaces 10c, and 20c. That is, the sides that will become the inner surfaces 10a and 20a are not plated. While the specific method for this is not limited, the outer layers 10e and 20e that form the outer surfaces 10b, 20b, side surfaces 10c, and 20c can be formed with a plated coating by, for example, masking the sides that will become the inner surfaces 10a and 20a with resist or masking tape. The plated coating may be electrolytic plating or electroless plating. This results in a laminate for the first sheet 10 and a laminate for the second sheet 20. By obtaining such a laminate, the metal sheet already has an outer peripheral shape equipped with an outer layer and an inner layer, so the amount of plating required can be reduced compared to processing a pre-plated metal sheet. In addition, a plating layer can also be formed on the side of the metal sheet, which can suppress deformation due to lateral impact during transportation or assembly of electronic devices, etc.

[0112] The liquid flow path grooves 14a, liquid flow path grooves 15a, vapor flow path grooves 16, vapor flow path grooves 26, vapor flow path connecting grooves 17, and vapor flow path connecting grooves 27 described above are formed in each of these laminates by half etching, thereby obtaining the first sheet 10 and the second sheet 20. Here, the plating film treatment is performed before the grooves are formed by half etching, but this is not limiting, and the plating film treatment may be performed as described above after the grooves are formed by half etching.

[0113] Next, the inner surface 10a of the first sheet 10 and the inner surface 20a of the second sheet 20 are placed face to face, and are positioned using the holes 13a and 23a as positioning means, and are temporarily fastened. The method of temporarily fastening is not particularly limited, but examples include resistance welding, ultrasonic welding, and adhesion using an adhesive. After the sheets are temporarily attached, they are then bonded permanently by diffusion bonding. Brazing may also be used instead of diffusion bonding.

[0114] After bonding, a vacuum is drawn through the formed injection channel 5 to reduce the pressure in the sealed space 2. Then, the working fluid is injected into the reduced-pressure sealed space 2 through the injection channel 5, and the working fluid enters the sealed space 2. Then, the injection channel 5 is closed by melting the injection parts 12 and 22 with a laser or by crimping. This allows the working fluid to be stably held inside the sealed space 2, forming a vapor chamber.

[0115] In this embodiment, a plating film process is used as a means for obtaining a laminate for the first sheet 10 and a laminate for the second sheet, but this is not limited to this, and the vapor chamber can also be manufactured using a composite material (so-called clad material) in which multiple layers are pre-laminated.

[0116] Next, the action of vapor chamber 1 when it is activated will be described. Figure 14 shows a schematic diagram of vapor chamber 1 disposed inside portable terminal 40, which is one form of electronic device. Here, vapor chamber 1 is shown by a dotted line because it is disposed inside housing 41 of portable terminal 40. Portable terminal 40 is configured with housing 41 that houses various electronic components, and display unit 42 that is exposed so that images can be seen to the outside through an opening in housing 41. One of these electronic components is electronic component 30, which is to be cooled by vapor chamber 1, and is disposed inside housing 41.

[0117] The vapor chamber 1 is installed inside the housing of a mobile terminal or the like, and is attached to an electronic component 30, such as a CPU, which is the object to be cooled. The electronic component 30 is attached to the outer surface 10b or outer surface 20b of the vapor chamber 1 directly, or via a highly thermally conductive adhesive, sheet, tape, or the like.

[0118] 15 is a diagram illustrating the behavior of the working fluid. For ease of explanation, the second sheet 20 is omitted from this diagram, and the inner surface 10a of the first sheet 10 is shown. When the electronic components 30 generate heat, the heat is transferred by thermal conduction within the first sheet 10 and reaches the condensate present in the sealed space 2 near the electronic components 30. The condensate absorbs the heat and evaporates, thereby cooling the electronic components 30.

[0119] The vaporized working fluid becomes vapor and moves through the vapor flow path 4. The vaporized working fluid may move in a vibrating manner within the vapor flow path 4 as shown by the solid straight arrow in Fig. 15, or may move in one direction away from the electronic component 30, which is the heat source, without vibrating. During this movement, the working fluid is cooled as heat is absorbed by the first sheet 10 and the second sheet 20. The first sheet 10 and the second sheet 20 absorb heat from the vapor and transfer the heat to the housing of the portable terminal device or the like that is in contact with their outer surfaces 10b and 20b, and the heat is finally released into the outside air. Then, the working fluid that absorbs heat while moving through the vapor flow path 4 condenses and becomes a liquid.

[0120] A portion of the condensate generated in the steam flow path 4 moves from the liquid communication openings etc. to the condensate flow paths 3. Since the condensate flow paths 3 in this embodiment are provided with the liquid communication openings 14c and 15c, the condensate is distributed to the plurality of condensate flow paths 3 through these liquid communication openings 14c and 15c.

[0121] The condensate that has entered the condensate flow path 3 moves toward the heat source, electronic component 30, due to the capillary force of the condensate flow path, as indicated by the dotted straight arrow in Fig. 15. It is then vaporized again by the heat from the heat source, electronic component 30, and the above process is repeated.

[0122] As described above, the vapor chamber 1 allows the working fluid to move smoothly and efficiently through the vapor flow path and the high capillary force in the condensate flow path, thereby increasing the amount of heat transport.

[0123] In the vapor chamber 1 described so far, the entire surfaces of the outer surface 10b, the outer surface 20b, the side surface 10c, and the side surface 20c are formed by the outer layer 10e and the outer layer 20e. However, if necessary, a portion of the outer layer 10e and / or the outer layer 20e may be removed to expose a portion of the inner layer 10d and / or the inner layer 20d, and this portion may also form a portion of the outer surface 10b, the outer surface 20b, the side surface 10c, and the side surface 20c. Several embodiments will be described below.

[0124] Fig. 16 is a diagram illustrating a second embodiment of a vapor chamber 101, and corresponds to Fig. 12. In the vapor chamber 101, the thickness direction ends of the side surfaces 10c and 20c are formed by outer layers 10e and 20e, and the inner layers 10d and 20d are exposed at the center in the thickness direction, which is the joint between the first sheet 10 and the second sheet 20, to form the side surfaces 10c and 20c. Even with this structure, the side surfaces 10c and 20c of the vapor chamber 101 are resistant to external impacts and are prevented from deformation or destruction. Furthermore, with this structure, when the first sheet 10 and the second sheet 20 are joined, the outer layers 10e and 20e do not interfere with the joining of the inner layers 10d and 20d, facilitating the joining.

[0125] 17 and 18 are diagrams illustrating a vapor chamber 201 of a third embodiment, with Fig. 17 being a perspective view and Fig. 18 being a cross section taken along the line XVIII-XVIII in Fig. 17. In the vapor chamber 201, the outer surfaces 10b and 20b are provided with outer layers 10e and 20e only in areas that overlap the sealed space 2 in which the condensate flow path 3 and the vapor flow path 4 are provided in a plan view of the vapor chamber 201, and the inner layers 10d and 20d are exposed in other areas. Such outer layers 10e and 20e can prevent deformation of the areas where the flow paths, which are prone to deformation, are formed. On the other hand, the thermal resistance is reduced in the areas where the inner layers 10d and 20d are exposed, thereby improving the thermal performance.

[0126] In addition, in this embodiment, outer layers 10e and 20e are not provided in injection parts 12 and 22. That is, the structure is such that no outer layer is disposed in the area where the working fluid is injected into the sealed space and sealed. This makes it easy to seal this area and also makes it easy to inspect whether the sealing is performed properly.

[0127] FIG. 19 is a diagram illustrating a vapor chamber 201' according to a modified example of the vapor chamber 201. FIG. 19 is a diagram corresponding to FIG. 18. In the vapor chamber 201', the outer layer 10e is disposed on only one side of the vapor chamber 201 (the first sheet 10 in this embodiment). This also makes it possible to prevent deformation of the portion where the flow path, which is prone to deformation, is formed. Meanwhile, in the portions where the inner layer 10d and the inner layer 20d are exposed, the thermal resistance is reduced, thereby improving thermal performance. When arranging such vapor chamber 201' in an electronic device, it is preferable to arrange the heat source on the outer surface 10b side and the housing on the outer surface 20b side, which reduces the thermal resistance on the housing side where heat must be transferred over a wide area.

[0128] Fig. 20 is a perspective view illustrating a vapor chamber 301 according to the fourth embodiment, as viewed from the first sheet 10 side. In the vapor chamber 301, the outer layer 10e is removed in the area where the heat source is placed, and the inner layer 10d is exposed in this area to form the outer surface 10b. This reduces the thermal resistance in this area, and by placing a heat source here, heat from the heat source can be efficiently transferred to the working fluid, further increasing the cooling capacity.

[0129] 21 to 28 are diagrams illustrating a vapor chamber 401 according to the fifth embodiment. Fig. 21 is an external perspective view of the vapor chamber 401, and Fig. 22 is an exploded perspective view of the vapor chamber 401.

[0130] 21 and 22, the vapor chamber 401 has a first sheet 410, a second sheet 420, and a third sheet 430. The first sheet 410, the second sheet 420, and the third sheet 430 are stacked and joined (by diffusion bonding, brazing, or the like), thereby forming a sealed space 402 surrounded by the first sheet 410, the second sheet 420, and the third sheet 430 between the first sheet 410 and the second sheet 420 (see FIG. 26), and the working fluid is sealed in this sealed space 402.

[0131] In this embodiment, the first sheet 410 is a sheet-like member as a whole. The first sheet 410 is composed of flat surfaces on both the front and back sides, and includes an inner surface 410a, an outer surface 410b opposite the inner surface 410a, and a side surface 410c that spans the inner surface 410a and the outer surface 410b to form a thickness.

[0132] In this embodiment, first sheet 410 is configured to have inner layer 410d made of a material that forms inner surface 410a, and outer layer 410e made of a material that forms outer surface 410b. That is, first sheet 410 is configured by laminating multiple layers, one of which forms inner surface 410a and the other layers form outer surface 410b. The aspects of inner layer 410d and outer layer 410e can be considered similar to those of inner layer 10d and outer layer 10e described above.

[0133] The first sheet 410 includes a main body 411 and an injection part 412. The main body 411 is a sheet-like part that forms an enclosed space in which the working fluid moves, and in this embodiment, is a rectangle with arcuate (so-called R) corners in a plan view. Injection portion 412 is a portion where working fluid is injected into the sealed space formed by first sheet 410, second sheet 420, and third sheet 430, and in this embodiment is a sheet-like shape that is rectangular in plan view and protrudes from one side of main body 411 that is rectangular in plan view. In this embodiment, injection portion 412 of first sheet 410 has flat surfaces on both the inner surface 410a side and the outer surface 410b side.

[0134] In this embodiment, second sheet 420 is a sheet-like member as a whole. Second sheet 420 is composed of flat surfaces on both the front and back sides, and includes inner surface 420a, outer surface 420b opposite inner surface 420a, and side surface 420c that spans between inner surface 420a and outer surface 420b to form a thickness.

[0135] In this embodiment, second sheet 420 also has inner layer 420d made of a material that forms inner surface 420a, and outer layer 420e made of a material that forms outer surface 420b. That is, second sheet 420 is also made of a plurality of laminated layers, one of which forms inner surface 420a and the other layers form outer surface 420b. The aspects of inner layer 420d and outer layer 420e can be considered similar to those of inner layer 10d and outer layer 10e described above.

[0136] The second sheet 420 also has a main body 421 and an injection portion 422 .

[0137] In this embodiment, third sheet 430 is a sheet that is sandwiched and overlapped between inner layer 410d of first sheet 410 and inner layer 420d of second sheet 420, and a structure for moving the working fluid is formed in main body 431. Fig. 23 shows a plan view of third sheet 430. Fig. 23(a) is a view of the surface that overlaps second sheet 420, and Fig. 24(b) is a view of the surface that overlaps first sheet 410. Fig. 24 also shows a cross section taken along line XXIV-XXIV in Fig. 23(a), and Fig. 25 shows a cross section taken along line XXV-XXV in Fig. 23(a).

[0138] The third sheet 430 includes a main body 431 and an injection portion 432. The main body 431 is a sheet-like portion that forms an enclosed space in which the working fluid moves, and in this embodiment, is a rectangle with arcuate (so-called R) corners in a plan view. Injection portion 432 is a portion where working fluid is injected into the sealed space formed by first sheet 410, second sheet 420, and third sheet 430, and in this embodiment is in the form of a sheet that is square in plan view and protrudes from one side of main body 431, which is rectangular in plan view. Injection portion 432 has injection groove 432a formed on the surface that overlaps first sheet 410. Injection groove 432a can be considered to be similar to injection groove 22a described above.

[0139] The main body 431 is provided with an outer periphery joining portion 433 , an outer periphery liquid flow path portion 434 , an inner liquid flow path portion 435 , a steam flow path slit 436 , and a steam flow path communication groove 437 .

[0140] The outer peripheral joining portion 433 is a portion formed along the outer periphery of the main body 431. One surface of the outer peripheral joining portion 433 is overlapped and joined (diffusion bonding, brazing, etc.) to the surface of the first sheet 410, and the other surface is overlapped and joined (diffusion bonding, brazing, etc.) to the surface of the second sheet 420. This forms an enclosed space 402 surrounded by the first sheet 410, the second sheet 420, and the third sheet 430, and the working fluid is sealed therein. The outer peripheral joint 433 can be considered to be similar to the outer peripheral joint 13 described above.

[0141] Furthermore, holes 433a penetrating in the thickness direction (z direction) are provided at the four corners of the outer peripheral joint 433 of the main body 431. These holes 433a function as positioning means when the first sheet 410 and the second sheet 420 are superimposed.

[0142] The peripheral liquid flow path section 434 functions as a liquid flow path section and is a portion that constitutes a part of the condensed liquid flow path 3, which is a flow path through which the working fluid passes when condensed and liquefied. The peripheral liquid flow path section 434 is formed along the inside of the peripheral joint section 433 of the main body 431, and is provided so as to be annular along the outer periphery of the sealed space 402. A liquid flow path groove 434a is formed on the surface of the peripheral liquid flow path section 434 that faces the second sheet 420. The outer peripheral liquid flow path section 434 and the liquid flow path grooves 434a provided therein can be considered to be similar to the outer peripheral liquid flow path section 14 and the liquid flow path grooves 14a described above.

[0143] The inner liquid flow path section 435 also functions as a liquid flow path section, and is a section that constitutes part of the condensed liquid flow path 3 through which the working fluid passes when condensed and liquefied. The inner liquid flow path section 435 is formed inside the ring of the annular outer peripheral liquid flow path section 434 in the main body 431. The inner liquid flow path section 435 in this embodiment is a section that is rectangular in plan view of the main body 431 and extends in a straight line in a direction parallel to the long side (x direction), and multiple (three in this embodiment) inner liquid flow path sections 435 are arranged at intervals in a direction parallel to the short side (y direction) and are disposed between the steam flow path slits 436.

[0144] Liquid flow path grooves 435a, which are linear grooves parallel to the extension direction of the inner liquid flow path section 435, are formed on the surface of the inner liquid flow path section 435 facing the second sheet 420. The inner liquid flow path section 435 and the liquid flow path grooves 435a can be considered to be similar to the inner liquid flow path section 15 and the liquid flow path grooves 15a described above.

[0145] The steam flow path slit 436 is a portion through which the working fluid in the vapor and condensed liquid states moves, and is a slit that constitutes the steam flow path 4. The steam flow path slit 436 is configured as a linear slit formed inside the ring of the annular outer peripheral liquid flow path section 434 in the main body 431. More specifically, the steam flow path slit 436 in this embodiment is formed between adjacent inner liquid flow path sections 435 and between the outer peripheral liquid flow path section 434 and the inner liquid flow path section 435, and is a slit that is rectangular in plan view of the main body 431 and extends in a direction parallel to the long side (x direction). Therefore, the steam flow path slit 436 penetrates the third sheet 430 in the thickness direction (z direction). A plurality of (four in this embodiment) vapor flow path slits 436 are arranged in a direction parallel to the short side (y direction). Therefore, as can be seen from Fig. 24, the third sheet 430 has a shape in which outer peripheral liquid flow path portions 434, inner liquid flow path portions 435, and vapor flow path slits 436 are alternately repeated in the y direction.

[0146] Such a steam flow path slit 436 can be considered to be similar to the steam flow path 4 formed by combining the steam flow path groove 16 and the steam flow path groove 26 described above.

[0147] In this embodiment, the cross-sectional shape of the steam flow path slit 436 is formed by overlapping portions of an ellipse, with the center in the thickness direction protruding, but this is not limited to this and other shapes such as a square, rectangle, trapezoid, or other quadrilateral, a triangle, a semicircle, etc. may also be used.

[0148] The steam flow path communication groove 437 is a groove that forms a flow path that communicates the multiple steam flow path slits 436. This makes it possible to balance the movement of the working fluid that occurs in the steam flow path in the direction in which the inner liquid flow path section 435 extends. This also makes it possible to equalize the working fluid in the vapor flow path, transport the vapor over a wider area, and efficiently utilize the condensate flow paths provided by the many liquid flow grooves 434a, 435a.

[0149] The steam flow path communication grooves 437 in this embodiment are formed between both ends of the inner liquid flow path section 435 in the extending direction and both ends of the steam flow path slits 436 in the extending direction, and the outer circumferential liquid flow path section 434. The steam flow path communication grooves 437 only need to be able to communicate with adjacent steam flow path slits 436, and the shape thereof is not particularly limited, but can be considered to be similar to a flow path formed by overlapping the above-mentioned steam flow path communication grooves 17 and 27. In this embodiment, a hole 437a is provided in a part of the vapor flow path communication groove 437 so as not to block the injection groove 432a.

[0150] Such a third sheet 430 can be produced by etching each side separately, etching both sides simultaneously, pressing, cutting, or the like.

[0151] Figures 26 to 28 are diagrams illustrating the structure when first sheet 410, second sheet 420, and third sheet 430 are combined to form vapor chamber 401. Figure 26 shows a cross section taken along line XXVI-XXVI in Figure 21, and Figure 27 shows an enlarged view of a portion of Figure 26. Figure 28 shows a cross section taken along line XXVIII-XXVIII in Figure 21.

[0152] As can be seen from Figure 21 and Figures 26 to 28, first sheet 410, second sheet 420, and third sheet 430 are overlappingly arranged and joined to form vapor chamber 401. At this time, first sheet 410 is arranged so that inner surface 410a (inner layer 410d) faces one surface of third sheet 430 (the surface on which liquid flow path grooves 434a and 435a are not arranged), and second sheet 420 is arranged so that inner surface 420a (inner layer 420d) faces the other surface of third sheet 430 (the surface on which liquid flow path grooves 434a and 435a are arranged). Injection sections 412, 422, and 432 of each sheet are also overlapped in a similar manner.

[0153] As a result, an enclosed space 402 surrounded by the first sheet 410, the second sheet 420, and the third sheet 430 is formed between the first sheet 410 and the second sheet 420. A condensate flow path 3 and a vapor flow path 4 are formed in this enclosed space 402. The same concept as that of the vapor chamber described above can be applied to the configuration of the condensate flow path 3 and the vapor flow path 4 in this enclosed space 402. [Explanation of symbols]

[0154] 1, 101, 201, 301, 401 Vapor chamber 2, 102, 202, 302, 402 Closed space 3 Condensate flow path 4 Steam flow path 10, 110, 210, 310, 410 First sheet 10a Inner surface 10b External surface 10c side 10d inner layer 10e outer layer 11. Main unit 12 Injection part 13 Peripheral joint 14 Peripheral liquid flow path section 14a Liquid flow groove 14c Fluid communication opening 15 Inner liquid flow path section 15a Liquid flow groove 15c Liquid communication opening 16 Steam flow groove 17 Steam flow path connecting groove 20, 120, 220, 320, 420 Second sheet 20a inner surface 20b External surface 20c side 20d inner layer 20e outer layer 21 Main Unit 22 Injection part 23 Peripheral joint 24 Peripheral liquid flow path section 25 Inner liquid flow path section 26 Steam flow channel groove 27 Steam flow path connecting groove 430 Third seat 436 Steam flow slit

Claims

1. A vapor chamber in which a sealed space is formed between a plurality of sheets and a working fluid is sealed in the sealed space, The sealed space includes a condensate flow path, which is a flow path through which the working fluid moves in a condensed liquid state; a vapor flow path through which the working fluid moves in the form of vapor and condensate; an inner layer that is located inside the vapor chamber in the thickness direction and forms the sealed space; an outer layer located outside the inner layer in the thickness direction of the vapor chamber, a side surface of the vapor chamber is covered with the outer layer; The inner layer is exposed at a portion of the vapor chamber where a heat source is disposed, In a thickness direction of the vapor chamber, a surface where the inner layer is exposed is recessed toward the sealed space side more than a surface where the inner layer is not exposed, A vapor chamber, wherein the upper yield point or 0.2% yield strength of the material constituting the outer layer is greater than the upper yield point or 0.2% yield strength of the material constituting the inner layer.

2. A vapor chamber in which a sealed space is formed between a plurality of sheets and a working fluid is sealed in the sealed space, The sealed space includes a condensate flow path, which is a flow path through which the working fluid moves in a condensed liquid state; a vapor flow path through which the working fluid moves in the form of vapor and condensate; A plurality of inner layers are located inside the vapor chamber in the thickness direction and form the sealed space; an outer layer located outside the inner layer in the thickness direction of the vapor chamber, The side surface of the vapor chamber is covered with the outer layer, and the inner layers are exposed at the joints of the sheets on the side surface, In the side surface of the vapor chamber, a surface on which the plurality of inner layers are exposed is recessed toward the sealed space side relative to a surface on which the plurality of inner layers are not exposed, A vapor chamber, wherein the upper yield point or 0.2% yield strength of the material constituting the outer layer is greater than the upper yield point or 0.2% yield strength of the material constituting the inner layer.

3. 3. The vapor chamber according to claim 1, wherein the outer layer is a plated layer.

4. The housing and an electronic component disposed inside the housing; An electronic device comprising: the vapor chamber according to any one of claims 1 to 3, which is arranged in direct contact with the electronic component or in contact with another member therebetween.

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