Vapor chamber and electronic apparatus

Abstract

To provide a vapor chamber capable of increasing a heat transport capacity even when it has a flow channel where directions change.SOLUTION: A vapor chamber includes, in a sealed space, condensed liquid flow channels, which are flow channels where working fluid moves in a state of a condensed liquid, and a plurality of vapor flow channels where the working fluid moves in a state of a vapor and a condensed liquid, whose flow channel cross sectional area is larger than that of the condensed liquid flow channel. The plurality of condensed liquid flow channels and the plurality of vapor flow channels include linear sections that extend linearly, and curved sections continued to the linear sections, where the directions that the plurality of condensed liquid flow channels and the plurality of vapor flow channels extend change. The vapor flow channels in the curved sections are configured so that their flow channel cross sectional area is larger than that of the vapor flow channels in the linear sections.SELECTED DRAWING: Figure 21

Description

[Technical field]

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

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

[0003] On the other hand, in recent years, the thickness of these electronic devices has become remarkable, and a cooling means thinner than the conventional heat pipe has become necessary. In response to this, vapor chambers have been proposed. Vapor chambers are also called sheet-type heat pipes, and are devices that apply the concept of heat transport by heat pipes to flat plate-shaped members. That is, in vapor chambers, a working fluid is sealed between opposing flat plates, and the phase change of this working fluid is used to transport and diffuse heat in the heat source to cool the heat source.

[0004] Such vapor chambers are arranged inside electronic devices, and since many other components are arranged inside electronic devices, there are often restrictions on where the vapor chamber can be arranged. As a result, it is not always possible to provide a flow path for the working fluid in a straight line, and it has been necessary to deal with the restrictions on arrangement by providing a flow path that has a curved portion so that the direction changes, as described in Patent Document 1, for example. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-205693 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, as described in Patent Document 1, a vapor chamber in which the direction of the flow path of the working fluid changes has the problem that it is difficult to increase the heat transport capacity.

[0007] In view of the above problems, the present invention aims to provide a vapor chamber that can increase the heat transport capacity even when the vapor chamber has a flow path whose direction changes. Also, the present invention provides an electronic device equipped with the vapor chamber. [Means for solving the problem]

[0008] As a result of intensive research, the inventor has found that in a vapor chamber having multiple vapor flow paths whose directions change, the flow resistance of the working fluid increases when the direction of the flow path of the working fluid changes, making it difficult for the vapor to reach the end of the flow path, and heat transport may not be sufficient. In addition, it has been found that since the lengths of the multiple vapor flow paths are different, differences in flow resistance occur, and the working fluid does not move in a balanced manner, so that when the difference in flow resistance becomes large, the heat transport capacity decreases and it may not be possible to achieve the expected performance. Based on these findings, the inventor has completed the present invention. The present invention will be described below.

[0009] One embodiment of the present invention is a vapor chamber in which a working fluid is sealed in an enclosed space, the enclosed 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 multiple vapor flow paths, which have a flow path cross-sectional area larger than that of the condensate flow path, and through which the working fluid moves in a vapor and condensed liquid state, the vapor chamber having a straight section in which the multiple condensate flow paths and the multiple vapor flow paths extend linearly, and a curved section continuous with the straight section and in which the extension direction of the multiple condensate flow paths and the multiple vapor flow paths changes, the vapor chamber being configured such that the flow path cross-sectional area of ​​the vapor flow path in the curved section is larger than that of the vapor flow path in the straight section. Effect of the Invention

[0010] According to the present invention, even when the vapor chamber has a flow path whose direction changes, the heat transport capacity can be increased. [Brief description of the drawings]

[0011] [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. [Diagram 2] FIG. 2 is a perspective view of the first sheet 10. As shown in FIG. [Diagram 3] FIG. 3 is a plan view of the first sheet 10. As shown in FIG. [Figure 4] FIG. 4 is a cross section of the first sheet 10. [Diagram 5] 5(a) and 5(b) are other cross-sectional views of the first sheet 10. FIG. [Figure 6] FIG. 6 is a partially enlarged plan view of the outer peripheral liquid flow path section 14. As shown in FIG. [Figure 7] FIG. 7 is a partially enlarged plan view of the outer peripheral liquid flow path section 14 according to another embodiment. [Figure 8] FIG. 8(a) is a cross section focusing on the inner liquid flow path section 15, and FIG. 8(b) is an enlarged plan view of a portion of the inner liquid flow path section 15. [Figure 9] 9(a) to 9(c) are diagrams for explaining examples of the shape of the curved portion 18c. [Figure 10] FIG. 10 is a diagram for explaining an example in which pillars 16a are provided in the steam flow passage groove 16. In FIG. [Figure 11] FIG. 11(a) is a plan view focusing on the curved portion 18c, and FIG. 11(b) is a diagram showing the curved portion 18c in another example. [Figure 12] FIG. 12 is a diagram showing a curved portion 18c in another example. [Figure 13] FIG. 13 is a perspective view of the second sheet 20. As shown in FIG. [Figure 14] FIG. 14 is a plan view of the second sheet 20. As shown in FIG. [Figure 15] FIG. 15 is a cross section of the second sheet 20. [Figure 16] FIG. 16 is another cross-section of the second sheet 20. [Figure 17] FIG. 17 is a cross-sectional view of the vapor chamber 1. [Figure 18] FIG. 18 is an enlarged view of a portion of FIG. [Figure 19] FIG. 19 is another cross-sectional view of the vapor chamber 1. [Figure 20] 20(a) to 20(c) are diagrams for explaining examples of the configuration of the condensate flow path. [Figure 21] FIG. 21 is a diagram illustrating the condensate flow path 3 and the steam flow path 4. As shown in FIG. [Figure 22] FIG. 22 is a perspective view illustrating an electronic device 40. As shown in FIG. [Diagram 23] FIG. 23 is a diagram illustrating the operation of the vapor chamber 1. [Figure 24] FIG. 24 is a perspective view of the exterior of the vapor chamber 201. [Diagram 25] FIG. 25 is an exploded perspective view of the vapor chamber 201. [Figure 26] FIG. 26(a) is a view of the third sheet 230 as seen from one surface side, and FIG. 26(b) is a view of the third sheet 230 as seen from the other surface side. [Figure 27] FIG. 27 is a cross section of the third sheet 230. [Figure 28] FIG. 28 is another cross-section of the third sheet 230. [Figure 29] FIG. 29 is a cross-sectional view of the vapor chamber 201. [Diagram 30] FIG. 30 is an enlarged view of a portion of FIG. [Diagram 31] FIG. 31 is another cross-sectional view of the vapor chamber 201. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Each embodiment will be described below with reference to the drawings. However, the present invention is not limited to these embodiments. In the drawings shown below, the size and ratio of the components may be changed or exaggerated for ease of understanding. In addition, for ease of viewing, illustrations of parts that are not necessary for explanation and repeated reference symbols may be omitted.

[0013] Fig. 1(a) shows an external perspective view of the vapor chamber 1 according to the first embodiment, and Fig. 1(b) shows an exploded perspective view of the vapor chamber 1. In these figures and each of the following figures, for convenience as necessary, arrows (x, y, z) showing mutually orthogonal directions are also shown. Here, the xy in-plane direction is the direction along the plate surface of the vapor chamber 1, which is flat, and the z direction is the thickness direction.

[0014] 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 hollow space between the first sheet 10 and the second sheet 20, and a working fluid is sealed in this hollow space to form a sealed space 2 (see, for example, FIG. 17).

[0015] In this embodiment, the first sheet 10 is a sheet-like member as a whole, and is L-shaped in a plan view. Fig. 2 shows a perspective view of the first sheet 10 seen from the inner surface 10a side, and Fig. 3 shows a plan view of the first sheet 10 seen from the inner surface 10a side. Fig. 4 shows a cross section of the first sheet 10 taken along line IV-IV in Fig. 3. The first sheet 10 has an inner surface 10a, an outer surface 10b opposite to the inner surface 10a, and a side surface 10c extending between 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 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 to form a hollow portion, into which the working fluid is sealed to form the sealed space 2.

[0016] The thickness of the first sheet 10 is not particularly limited, but is preferably 0.01 mm or more and 1.0 mm or less, and more preferably 0.05 mm or more and 0.2 mm or less, which increases the number of situations in which it can be used as a thin vapor chamber.

[0017] The first sheet 10 includes a main body 11 and an injection portion 12. The main body 11 is in the form of a sheet that forms a portion through which the working fluid moves, and in this embodiment, is L-shaped having a curved portion in a plan view. The injection section 12 is a section where the working fluid is injected into the hollow section 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 the L-shaped main body 11 in plan view. In this embodiment, both the inner surface 10a side and the outer surface 10b side of the injection section 12 of the first sheet 10 are flat surfaces.

[0018] A structure for moving the working fluid is formed on the inner surface 10a side of the main body 11. Specifically, this structure includes an outer periphery joining portion 13, an outer periphery liquid flow passage portion 14, an inner liquid flow passage portion 15, a steam flow passage groove 16, and a steam flow passage connecting groove 17 on the inner surface 10a side of the main body 11.

[0019] 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 and joined (by diffusion bonding, brazing, etc.) to the outer peripheral joining portion 23 of the second sheet 20, thereby forming a hollow portion between the first sheet 10 and the second sheet 20, and a working fluid is sealed in this hollow portion to form the sealed space 2. Figure 3 and Figure 4 show A 10The width of the outer peripheral joint 13 shown in can be set as needed, but is preferably 0.05 mm to 5.0 mm at its narrowest. If the width is smaller than 0.05 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. If the width is larger than 5.0 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.

[0020] The peripheral liquid flow path section 14 functions as a liquid flow path section and constitutes a part of the condensed liquid flow path 3 (see, for example, FIG. 18), which is a flow path through which the working fluid passes when condensed and liquefied. FIG. 5(a) shows the part indicated by the arrow Va in FIG. 4, and FIG. 5(b) shows a cross section taken along the line Vb-Vb in FIG. 3. Both figures show the cross-sectional shape of the peripheral liquid flow path section 14. Also, FIG. 6 shows an enlarged plan view of the peripheral liquid flow path section 14 as seen from the direction indicated by the arrow VI in FIG. 5(a).

[0021] As can be seen from these figures, the peripheral liquid flow path section 14 is formed along the inside of the peripheral joint 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 is also formed with liquid flow path grooves 14a that are multiple grooves extending parallel to the direction in which the peripheral liquid flow path section 14 extends, 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 5(a) and 5(b), the peripheral liquid flow path section 14 has the liquid flow path grooves 14a that are recesses in the cross section, and the walls 14b that are protrusions between the liquid flow path grooves 14a, which are repeated recesses and projections. Here, since the liquid flow path groove 14a is a groove, its cross-sectional shape has a bottom and an opening located on the opposite side facing the bottom.

[0022] 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 liquid flow path 3 (see FIG. 18, for example) 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 14a, the total internal volume of the condensate liquid flow path 3 as a whole can be ensured to be an appropriate size, and the condensate can flow at a required flow rate.

[0023] Furthermore, in the outer peripheral liquid flow passage portion 14, as can be seen from FIG. 6, adjacent liquid flow passage grooves 14a are communicated with each other through 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 passage grooves 14a, and allows the condensed liquid to flow efficiently. In addition, the communication openings 14c provided in the wall 14b adjacent to the steam flow passage groove 16 forming the steam flow passage 4 communicate the steam flow passage 4 with the condensed liquid flow passage 3. Therefore, by providing the communication openings 14c, the condensed liquid generated in the steam flow passage 4 can be smoothly moved to the condensed liquid flow passage 3, and the steam generated in the condensed liquid flow passage 3 can be smoothly moved to the steam flow passage 4, which also promotes the smooth movement of the working fluid.

[0024] In this embodiment, the communication openings 14c are arranged to face each other at the same position in the extension direction of the liquid flow path groove 14a, sandwiching the groove, as shown in Fig. 6. However, this is not limited to this, and the communication openings 14c may be arranged at different positions in the extension direction of the liquid flow path groove 14a, sandwiching the groove, as shown in Fig. 7, for example. That is, in this case, the communication openings 14c are arranged offset in the extension direction of the liquid flow path groove 14a. By providing the communication opening 14c in this offset manner, when viewed from the working fluid moving through the condensate flow path 3, the communication opening 14c does not appear on both sides at the same time, and even if the communication opening 14c appears, at least one side always has the wall 14b. Therefore, the capillary force can be obtained continuously. From this viewpoint, by forming the communication opening 14c in an offset manner, the capillary force acting on the working fluid can be kept high, and the condensate can flow smoothly.

[0025] The peripheral liquid flow path section 14 having the above-mentioned configuration preferably further has the following configuration. Figures 3, 4, 5(a), and 5(b) show 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 0.03 mm or more and 2 mm or less. If the width is less than 0.03 mm, there is a risk that the amount of liquid flowing on the outside will be insufficient. If the width exceeds 2 mm, there is a risk that there will not be enough space for the inner condensate flow path and steam flow path.

[0026] Regarding the liquid flow channel 14a, FIG. 1 The groove width indicated by is preferably 10 μm or more and 300 μm or less. In addition, the depth of the liquid flow path groove 14a indicated by D in Figures 5(a) and 5(b) is preferably 5 µm or more and 200 µm or less. This allows the capillary force of the liquid flow path required for the condensed 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 makes it possible to more reliably prevent the sheet from breaking when the working fluid freezes. In order to maximize the capillary force in the flow channel, 1 The aspect ratio (horizontal to vertical ratio) of the flow channel cross section, which is expressed by dividing C1 by D, is preferably greater than 1.0 or less than 1.0. Among these, from the viewpoint of ease of manufacture, it is preferable that C1 is greater than D, and the aspect ratio is preferably greater than 1.3.

[0027] Regarding the wall 14b, C in FIG. 2 The width indicated by is preferably 20 μm or more and 300 μm or less. If the width is less than 20 μm, the working fluid is easily broken due to repeated freezing and melting, and if the width is more than 300 μm, the width of the communication opening 14c becomes too large, which may hinder smooth communication of the working fluid with the adjacent condensate flow passage 3.

[0028] Regarding the communication opening 14c, C in FIG. 3 The size of the communication opening 14c along the direction in which the liquid flow path groove 14a extends is preferably 20 μm or more and 180 μm or less. Also, in Figure 6, C 4 The pitch between adjacent communication openings 14c in the direction in which liquid flow path groove 14a extends is preferably 300 μm or more and 2700 μm or less.

[0029] 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 semicircular bottom, or with a semi-elliptical bottom, etc.

[0030] Moreover, it is preferable that the liquid flow passage groove 14a is formed continuously along the edge of the sealed space. In other words, it is preferable that the liquid flow passage groove 14a extends in an annular shape around the entire circumference without being interrupted by other components. This reduces factors that hinder the movement of the condensed liquid, allowing the condensed liquid to move smoothly.

[0031] In this embodiment, the peripheral liquid flow path section 14 is provided, but it is not essential that the peripheral liquid flow path section 14 is provided, and the peripheral liquid flow path section 14 may not be provided depending on the shape of the vapor chamber, the relationship with the device to which the vapor chamber is applied, the usage environment, etc. In this embodiment, the peripheral part of the sealed space can be configured as a steam flow path to transport heat by steam to the peripheral part of the vapor chamber, which may result in higher heat uniformity.

[0032] Returning to Figures 2 to 4, the inner liquid flow path section 15 will be described. The inner liquid flow path section 15 also functions as a liquid flow path section, and is a part that constitutes a part of the condensed liquid flow path 3 through which the working fluid passes when condensed and liquefied. Figure 8(a) shows the part indicated by VIIIa in Figure 4. This figure also shows the cross-sectional shape of the inner liquid flow path section 15. Figure 8(b) shows an enlarged plan view of the inner liquid flow path section 15 as seen from the direction indicated by the arrow VIIIb in Figure 8(a).

[0033] As can be seen from these figures, the inner liquid flow path section 15 is formed inside the ring of the annular outer peripheral liquid flow path section 14 (or the outer peripheral joint section 13) on the inner surface 10a of the main body 11. As can be seen from Figures 2 and 3, the inner liquid flow path section 15 in this embodiment is a convex ridge extending with a curved portion, and is arranged at intervals in a direction different from the extension direction of multiple (five in this embodiment) inner liquid flow path sections 15, and is disposed between the steam flow path grooves 16. Each inner liquid flow path section 15 is formed with liquid flow path grooves 15a which are grooves parallel to the direction in which the inner liquid flow path section 15 extends, and a plurality of 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 4 and 8(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 shape. Here, since the liquid flow path groove 15a is a groove, its cross-sectional shape has a bottom and an opening on the opposite side facing the bottom.

[0034] By providing a plurality of liquid flow path grooves 15a in this manner, the depth and width of each liquid flow path groove 15a can be reduced, and the flow path cross-sectional area of ​​the condensate liquid flow path 3 (see FIG. 18, for example) 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 liquid flow path 3 as a whole can be ensured to be an appropriate size, and the condensate can flow at a required flow rate.

[0035] Furthermore, in the inner liquid flow passage section 15, as can be seen from FIG. 8(b), the adjacent liquid flow passage grooves 15a are connected to each other by the communication openings 15c provided at intervals in the wall 15b in the same manner as in FIG. 6 following the example of the outer circumferential liquid flow passage section 14. This promotes equalization of the amount of condensed liquid among the liquid flow passage grooves 15a, and allows the condensed liquid to flow efficiently. In addition, the communication openings 15c provided in the wall 15b adjacent to the steam flow passage groove 16 forming the steam flow passage 4 communicate the steam flow passage 4 and the condensed liquid flow passage 3. Therefore, by configuring the communication openings 15c as described later, the condensed liquid generated in the steam flow passage 4 can be smoothly moved to the condensed liquid flow passage 3, and the steam generated in the condensed liquid flow passage can be smoothly moved to the steam flow passage 4, which also promotes the smooth movement of the working fluid.

[0036] Similarly, in the inner liquid flow path section 15, similar to the example in FIG. 7, communication openings 15c may be disposed at different positions in the extension direction of one liquid flow path groove 15a, sandwiching the groove. By providing the communication opening 15c in such an offset manner, when viewed from the working fluid moving through the condensate flow path 3, the communication opening 15c does not appear on both sides at the same time, and even if the communication opening 15c appears, at least one side always has the wall 15b. Therefore, the capillary force can be obtained continuously. From this viewpoint, by forming the communication opening 15c in an offset manner, the capillary force acting on the working fluid can be kept high, and the working fluid can move more smoothly.

[0037] The inside liquid flow path section 15 having the above-mentioned configuration preferably further has the following configuration. Figures 3, 4, and 8(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 of the multiple 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 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.

[0038] Regarding the liquid flow channel 15a, FIG. 8(a) and FIG. 8(b) show 1 The groove width indicated by is preferably 10 μm or more and 300 μm or less. In addition, the depth of the groove indicated by G in FIG. 8(a) is preferably 5 μm or more and 200 μm or less. This allows the capillary force of the condensate flow path required for the movement of the 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 makes it possible to more reliably prevent the sheet from breaking when the working fluid freezes. In order to maximize the capillary force in the flow channel, 1 The aspect ratio (horizontal to vertical ratio) of the flow channel cross section, which is expressed by dividing F1 by G, is preferably greater than 1.0 or less than 1.0. Among these, from the viewpoint of production, it is preferable that F1 is greater than G, and the aspect ratio is preferably greater than 1.3.

[0039] Regarding the wall 15b, F is shown in Figs. 8(a) and 8(b). 2 The width indicated by is preferably 20 μm or more and 300 μm or less. If the width is less than 20 μm, the openings 15c are easily broken due to repeated freezing and melting of the working fluid, and if the width is more than 300 μm, the width of the communication openings 15c becomes too large, which may hinder smooth communication between the condensate flow paths 3.

[0040] Regarding the communication opening 15c, F is shown in FIG. 3 The size of the communication opening along the direction in which the liquid flow path groove 15a extends, indicated by is preferably 20 μm or more and 180 μm or less. Also, in Fig. 8(b), F 4 The pitch between adjacent communication openings 15c in the direction in which liquid flow path groove 15a extends is preferably 300 μm or more and 2700 μm or less.

[0041] 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 having a semicircular bottom or a semi-elliptical bottom.

[0042] Next, the steam flow passage groove 16 will be described. The steam flow passage groove 16 is a portion through which the working fluid in the form of vapor and condensed liquid moves, and constitutes a part of the steam flow passage 4. Fig. 3 shows the shape of the steam flow passage groove 16 in a plan view, and Fig. 4 shows the cross-sectional shape of the steam flow passage groove 16.

[0043] As can be seen from these figures, the steam flow path grooves 16 are 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 grooves that extend with curved portions. A plurality of steam flow path grooves 16 (six in this embodiment) are arranged in a direction different from the direction of extension. Therefore, as can be seen from FIG. 4, the first sheet 10 has a shape in which projections and recesses are repeated, with the inner liquid flow path sections 15 as projections and the steam flow path grooves 16 as recesses. Here, since the steam flow passage groove 16 is a groove, its cross-sectional shape has a bottom and an opening located on the opposite side facing the bottom.

[0044] The steam flow passage groove 16 may be configured so that when the steam flow passage 4 is formed in combination with the steam flow passage groove 26 of the second sheet 20, the working fluid moves through the steam flow passage 4. Therefore, it is preferable that the steam flow passage groove 16 further has the following configuration. Figures 3 and 4 show H 10 The width of the vapor flow passage groove 16 shown by is at least the width C of the liquid flow passage groove 14a and the liquid flow passage groove 15a. 1 , width F 1 It is preferable that the size is larger, ie, 100 μm or more and 2000 μm or less. On the other hand, in Fig. 4, 10The depth of the vapor flow passage groove 16 indicated by is formed to be at least greater than the depth D and depth G of the liquid flow passage groove 14a and the liquid flow passage groove 15a, and is preferably 10 μm or more and 300 μm or less. This ensures 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.

[0045] Here, the steam flow passage groove 16 is preferably configured so that when the steam flow passage 4 is formed by combining with the second sheet 20 as described later, the width of the steam flow passage 4 is larger than its height (size in the thickness direction). 10 I 10 The aspect ratio expressed by the value obtained by dividing the ratio by 1 is preferably 4.0 or more, and more preferably 8.0 or more.

[0046] 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.

[0047] The steam flow passage communication groove 17 is a groove that communicates the multiple steam flow passage grooves 16 and, in combination with the steam flow passage communication groove 27 of the second sheet 20, forms a flow passage that communicates the multiple steam flow passages 4 formed by the steam flow passage grooves 16 at their ends. This allows smooth movement of the working fluid generated in the steam flow passage 4 in the direction in which the inner liquid flow passage 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 many liquid flow path grooves 14a and liquid flow path grooves 15a.

[0048] As can be seen from Figures 2 and 3, the steam flow path communication groove 17 in this embodiment is 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 groove 16 extends, and the outer circumferential liquid flow path section 14. Figure 5(b) shows a cross section perpendicular to the communication direction of the steam flow path communication groove 17. Note that the boundary between the steam flow path communication groove 17 and the steam flow path groove 16 is not necessarily formed by a boundary due to its shape, and therefore, for ease of understanding, the boundary is shown by a dotted line in Figures 2 and 3.

[0049] The steam flow passage communication groove 17 may have any shape as long as it can communicate with the adjacent steam flow passage grooves 16, and may have, for example, the following configuration. In Fig. 3 and Fig. 5(b), 10 The width of the steam flow passage communication groove 17 indicated by is preferably 100 μm or more and 1000 μm or less. In addition, in Fig. 5(b), 10 The depth of the steam flow passage communicating groove 17 indicated by is preferably 10 μm or more and 300 μm or less, and is preferably the same as the depth I10 of the steam flow passage groove 16. This makes it easier to manufacture the first sheet 10.

[0050] In this embodiment, the cross-sectional shape of the steam flow passage 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 having a semicircular bottom or a semi-elliptical bottom.

[0051] In this embodiment, the first sheet 10 has curved portions 18c which are portions where the extending directions of the liquid flow path grooves 14a (outer peripheral liquid flow path section 14), the liquid flow path grooves 15a (inner liquid flow path section 15), and the steam flow path grooves 16 change. That is, the first sheet 10 has straight portions 18a where the liquid flow path grooves 14a (outer peripheral liquid flow path section 14), the liquid flow path grooves 15a (inner liquid flow path section 15), and the steam flow path grooves 16 extend linearly in the x direction, straight portions 18b where the liquid flow path grooves 14a (outer peripheral liquid flow path section 14), the liquid flow path grooves 15a (inner liquid flow path section 15), and the steam flow path grooves 16 extend linearly in the y direction, and curved portions 18c which connect the liquid flow path grooves 14a (outer peripheral liquid flow path section 14), the liquid flow path grooves 15a (inner liquid flow path section 15), and the steam flow path grooves 16 in the straight portions 18a and 18b. Therefore, one end of the curved portion 18c is connected to one straight portion 18a and the other end is connected to the other straight portion 18b, and the liquid flow path groove 14a (outer peripheral liquid flow path portion 14), the liquid flow path groove 15a (inner liquid flow path portion 15), and the steam flow path groove 16 are curved so that the flow changes direction from the x direction to the y direction and from the y direction to the x direction. Here, the boundary between the straight portion and the curved portion may be the point where the flow direction starts to change in each groove. The same can be considered below. Figure 11(a) shows an enlarged view of the curved portion 18c in Figure 3.

[0052] As can be clearly seen from Figures 3 and 11(a), in this embodiment, the width of the vapor flow channel groove 16 is made larger in the curved portion 18c than in the straight portion 18a and the straight portion 18b. This allows the flow resistance to be reduced in the curved portion 18c where the flow resistance increases due to the curvature of the flow channel, and the flow resistance of the vapor chamber as a whole is reduced, so that the movement of the working fluid becomes smoother and the heat transport capacity can be increased. In this case, the size of the width may be constant within the range of the curved portion 18c. This allows the flow resistance of the working fluid to be kept low.

[0053] There is no particular limitation on the means for making the width of the steam flow path groove 16 in the curved portion 18c larger than the width of the steam flow path groove 16 in the straight portion 18a and the straight portion 18b. In this embodiment, this is achieved by making the width of the outer circumferential liquid flow path section 14 and the inner liquid flow path section 15 in the portion belonging to the curved portion 18c smaller than the width of the outer circumferential liquid flow path section 14 and the inner liquid flow path section 15 in the portion belonging to the straight portion 18a and the straight portion 18b. In this case, the width of the liquid flow path groove 14a of the outer circumferential liquid flow path section 14 and the liquid flow path groove 15a of the inner liquid flow path section 15 in this portion may be made smaller, or the number of the liquid flow path grooves 14a and the liquid flow path grooves 15a may be reduced.

[0054] Alternatively, a means may be applied in which the width of the outer circumferential liquid flow path section 14 and the inner liquid flow path section 15 belonging to the curved section 18c are made the same as the width of the outer circumferential liquid flow path section 14 and the inner liquid flow path section 15 belonging to the straight section 18a and the straight section 18b, and the width of the steam flow path groove 16 in the curved section 18c is made larger than the width of the steam flow path groove 16 in the straight section 18a and the straight section 18b. Specific examples are shown in Figs. 9(a) to 9(c) for explanatory purposes.

[0055] 9(a) to 9(c) are explanatory views focusing on one steam flow groove 16. The other multiple steam flow grooves 16 can be considered in the same manner. The meanings of the symbols shown in FIGS. 9(a) to 9(c) are as follows: The steam flow groove 16 is formed on the inner wall of the curved portion 18c. in is the radius of curvature r in and its center is O 1 It is an arc shape. The steam flow groove 16 is formed on the outer wall of the curved portion 18c. out is the radius of curvature r out As will be explained later, the center of the 1 , O 2 , or O 3 It is an arc shape. The steam flow passage groove 16 has a width α at the straight portion 18a and the straight portion 18b, but the width of the steam flow passage groove 16 is increased to β at the curved portion 18c (α<β). The curve shown by the dotted line is a virtual line in the case where the width of the steam flow passage groove 16 is maintained at α even at the curved portion 18c, and the radius of curvature in this case is r c and its center is O 1 It is an arc shape. Here, the radius of curvature can be determined by considering a circle that passes through three points: two points where the direction of the walls (inner wall, outer wall) in the curved part starts to change, and one point in the middle of these two points. In addition, when the curvature is considered to be a part of a circle or an ellipse, as shown in Figures 9 and 11, the radius of the circle can be determined by considering the center side of the circle or the ellipse (i.e., O 1 , O 2 , O 3 The side opposite the center of the curved portion (the side opposite the center of the curved portion) is referred to as the "inside" of the curved portion, and the side opposite the center of the circle and ellipse is referred to as the "outside" of the curved portion. Furthermore, the shape of the curved portion is not limited to a shape like a part of a perfect circle, but may be a shape like a part of an ellipse, or may be a shape in which some of the multiple steam flow path grooves arranged in the curved portion are straight lines. Below, shapes related to curved portions can be considered in the same way.

[0056] In the example of FIG. 9(a), the outer wall w of the steam flow passage groove 16 at the curved portion 18c is out Radius of curvature r out is the radius of curvature r c is greater than (r out >r c ) with its center at O 1 It is.

[0057] In the example of FIG. 9(b), the outer wall w of the steam flow passage groove 16 at the curved portion 18c is out Radius of curvature r out is the radius of curvature r c Same as (r out =r c ), but its center is O 1 O 2 is located.

[0058] In the example of FIG. 9(c), the outer wall w of the steam flow channel groove 16 at the curved portion 18c is out Radius of curvature r out is the radius of curvature r in and radius of curvature rc Smaller than (r out <r in <r c ), with O at its center 1 O 3 is located.

[0059] In the examples of Figures 9(a) and 9(b), the outer wall w out In the embodiment, the straight line portion and the arc portion are connected by a single bent portion. However, the present invention is not limited to this, and the single bent portion may be configured to be multiple small bent portions or a curved portion, so that the direction of the portion changes gradually and smoothly.

[0060] The width of the steam flow path groove 16 in the curved portion 18c is not particularly limited as long as it is possible to reduce the flow resistance, but it is preferable that the width is 10% to 100% larger than that of the straight portions 18a and 18b. If the width is less than 10%, there is a risk that the flow resistance will not be sufficiently reduced. On the other hand, if the width of the steam flow path groove is increased by more than 100% in the curved portion 18c compared to that of the straight portions 18a and 18b, there is a risk that the flow resistance of the straight portions will increase.

[0061] In addition, although the above description focuses on the width of the steam flow groove, instead of or in addition to this, the depth of the steam flow groove 16 in the curved portion 18c may be made deeper than the straight portion 18a and the straight portion 18b. In a configuration in which the depth is changed, the expansion in the planar direction (xy direction) is suppressed, so that it is possible to secure many areas for arranging the condensate flow path and improve the heat transport capacity, or to make the outer periphery joint wider, thereby improving the reliability of the pressure resistance. In this case, the depth may be constant within the range of the curved portion 18c. This makes it possible to keep the flow resistance of the working fluid low. The difference in depth is not particularly limited as long as it is possible to reduce the flow resistance, but it is preferable that the steam flow channel grooves are 10% or more deeper in the curved section than in the straight section. If it is less than 10%, there is a risk that the flow resistance will not be sufficiently reduced.

[0062] 10, the vapor flow channel groove 16 in the curved portion 18c may have a plurality of pillars 16a arranged to stand upright from the bottom at the center in the width direction. These pillars serve as pillars supporting the first sheet 10 and the second sheet 20 of the vapor chamber 1. This makes it possible to suppress a decrease in strength caused by the widening of the width of the vapor flow channel due to the widening of the width of the vapor flow channel by widening the width of the vapor flow channel in the curved portion 18c. Specifically, this makes it possible to prevent the vapor flow channel from collapsing due to insufficient strength when joining or reducing pressure when combining the first sheet 10 and the second sheet 20 to form the vapor chamber 1, and when incorporating the vapor chamber into an electronic device. From this viewpoint, as shown in Fig. 10, pillars 16a can be provided for the long steam flow path groove 16. However, this is not limited to the above, and pillars 16a may be provided for any other steam flow path groove 16 as necessary, or pillars 16a may be provided for all the steam flow path grooves 16.

[0063] In this embodiment, as shown in Fig. 11(a), the width of the steam flow passage groove 16 is changed in a stepped manner at the connection between the curved portion and the straight portion. In contrast, in the example shown in Fig. 11(b), the width of the steam flow passage groove 16 is changed gradually at the connection between the curved portion and the straight portion by a tapered inclined surface. This makes it possible to prevent the generation of vortexes when the working fluid passes through the connection portion, and further to keep the flow resistance low.

[0064] In the above embodiment, the widths of the plurality of steam flow passage grooves 16 are the same in the curved portion 18c, but the present invention is not limited to this and the widths of the steam flow passage grooves may be changed. In this case, for example, the groove width of the steam flow path groove having a large radius of curvature may be made larger than the groove width of the steam flow path groove having a small radius of curvature, thereby reducing the flow resistance of the steam flow path having a large radius of curvature, which is a long distance traveled by the steam. In addition, the groove width of the steam flow path groove having a small radius of curvature may be made larger than the groove width of the steam flow path groove having a large radius of curvature, thereby reducing the flow resistance of the steam flow path at the curved portion due to the small radius. Furthermore, the groove width of the steam flow passage groove having a large radius and the groove width of the steam flow passage groove having a small radius may be made larger for the steam flow passage disposed in the center. By using the above-mentioned means, it is possible to further reduce the difference in flow resistance between a plurality of steam flow passage grooves, improve the balance of the movement of the working fluid, and increase the heat transport capacity.

[0065] In addition to the above, the first sheet 10 may have the following configuration. 3, in the curved portion 18c of this embodiment, the liquid flow path grooves 14a, the liquid flow path grooves 15a, and the steam flow path grooves 16 are configured such that, in the direction in which these flow path grooves are arranged, the radius of curvature of the steam flow path on one side of the arrangement direction is larger than the radius of curvature of the steam flow path on the other side of the arrangement direction.

[0066] In this embodiment, the grooves are curved to draw concentric arcs. However, the center positions of the arcs may be offset. Furthermore, the curved portion 18c is configured such that the radius of each groove increases as the length of the groove increases.

[0067] When multiple curved flow paths are arranged in a vapor chamber, the flow path length is shorter on the inside and longer on the outside, resulting in a large difference in flow resistance between the inside and outside. This difference in flow resistance leads to poor balance of the movement of the working fluid in the vapor chamber, which is one of the reasons why sufficient heat transport capacity cannot be achieved. In contrast, by using a configuration with the above-mentioned radius of curvature, it is possible to reduce the difference in flow resistance between the inside and outside, especially in the vapor flow path groove 16. This improves the balance of the movement of the working fluid and also increases the heat transport capacity.

[0068] However, the present invention is not limited to this, and as shown in FIG. 12, the radius of curvature of the plurality of steam flow path grooves 16 in the curved portion 18c may be the same.

[0069] In addition, in the curved portion 18c, the communication openings 14c and 15c (see FIG. 6 and FIG. 8(b)) provided in the walls 14b and 15b separating the liquid flow passage grooves 14a and 15a from the vapor flow passage groove 16 can be configured to have a pitch different from that of the other portions (straight portion 18a and straight portion 18b). The pitch of the communication openings in the curved portion may be larger or smaller than the pitch of the curved portions in the straight portion. Which form is to be adopted can be determined by comprehensively judging the form that can reduce the flow resistance, taking into consideration the effects of the overall shape of the vapor chamber, the position of the heat source, and the like. Alternatively, the curved portion 18c may not have the communication openings 14c and 15c provided in the walls 14b and 15b separating the liquid flow passage grooves 14a and 15c from the vapor flow passage groove 16. In a configuration in which the pitch of the communication openings in the curved portion is made larger than the pitch of the communication openings in the straight portion, the working fluid flowing through the steam flow groove 16 (steam flow path 4) can be prevented from entering the communication openings 14c and 15c at the curved portion 18c. In the curved portion 18c, the working fluid moving through the steam flow groove 16 (steam flow path 4) is forced to flow directly into the communication openings 14c and 15c due to its flow direction, so that the steam tends to enter the condensate flow path 3 and the flow resistance tends to increase due to the unevenness of the communication openings 14c and 15c. In response to this, by increasing the pitch of the communication openings 14c and 15c that contact the steam flow groove 16 at the curved portion 18c or by eliminating the communication openings 14c and 15c that contact the steam flow groove 16, it is possible to prevent such an increase in flow resistance, and further reduce the difference in flow resistance for each steam flow groove 16 (steam flow path 4), improving the balance of the movement of the working fluid, and increasing the heat transport capacity. On the other hand, when the pitch of the communication openings in the curved section is smaller than that of the straight section, the steam flowing through the steam flow groove (steam flow path) has more opportunities to strongly hit the wall surface in the curved section, which tends to make it easier to condense. In this case, by making the pitch of the communication openings in the curved section smaller than that of the straight section, the number of communication openings can be increased, and the condensate can be smoothly introduced into the liquid flow groove (condensate flow path), making it possible to prevent the steam flow path from being blocked by the condensate. This can prevent an increase in flow resistance, further reduce the difference in flow resistance between the steam flow grooves (steam flow paths), improve the balance of the movement of the working fluid, and may increase the heat transport capacity.

[0070] Next, the second sheet 20 will be described. In this embodiment, the second sheet 20 is also a sheet-like member as a whole, and is curved in an L-shape in a plan view. Fig. 13 shows a perspective view of the second sheet 20 seen from the inner surface 20a side, and Fig. 14 shows a plan view of the second sheet 20 seen from the inner surface 20a side. Fig. 15 shows a cut surface of the second sheet 20 when cut along XIII-XIII in Fig. 14. Fig. 16 shows a cut surface of the second sheet 20 when cut along XIV-XIV in Fig. 14. The second sheet 20 has an inner surface 20a, an outer surface 20b opposite to 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 through which the working fluid moves is formed on the inner surface 20a side. As described later, the inner surface 20a of the second sheet 20 and the inner surface 10a of the first sheet 10 are overlapped and joined so as to face each other to form a hollow portion, in which the working fluid is sealed to form the sealed space 2.

[0071] The thickness of the second sheet 20 is not particularly limited, but is preferably 0.01 mm or more and 1.0 mm or less, and more preferably 0.05 mm or more and 0.2 mm or less, which increases the number of situations in which it can be used as a thin vapor chamber.

[0072] The second sheet 20 includes a main body 21 and an injection portion 22. The main body 21 is in the form of a sheet that forms a portion through which the working fluid moves, and in this embodiment, is L-shaped having a curved portion in a plan view. The injection section 22 is a section where the working fluid is injected into the hollow section 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 the L-shaped main body 21 in plan view. In this embodiment, an injection groove 22a is formed on the inner surface 20a side of the injection section 22 of the second sheet 20, and communicates from the side surface 20c of the second sheet 20 to the inside of the main body 21 (the section that is to become the hollow section, the sealed space 2).

[0073] 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.

[0074] 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 overlaps and is joined (by diffusion bonding, brazing, or the like) to the outer peripheral joining portion 13 of the first sheet 10, thereby forming a hollow portion between the first sheet 10 and the second sheet 20, and a working fluid is sealed in this hollow portion to form the sealed space 2. Figures 14, 15, and 16 show A 20 The width of the outer peripheral joint 23 indicated by is the width A of the outer peripheral joint 13 of the main body 11. 10 It is preferable that the ratio is the same as

[0075] 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 FIG. 18, for example), which is a flow path through which the working fluid passes when it is condensed and liquefied.

[0076] The peripheral liquid flow path portion 24 is formed along the inside of the peripheral joint portion 23 on the inner surface 20a of the main body 21, and is formed so as to form a ring along the outer periphery of the sealed space 2. In this embodiment, the peripheral liquid flow path portion 24 of the second sheet 20 is a flat surface and is flush with the peripheral joint portion 23 before being joined to the first sheet 10, as can be seen from Figures 15 and 16. 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. A detailed embodiment of the combination of the first sheet 10 and the second sheet 20 will be described later. In addition, since the outer peripheral bonding portion 23 and the outer peripheral liquid flow path portion 24 are flush with each other in this way in the second sheet 20, there is no structural boundary line that distinguishes the two. However, for ease of understanding, the boundary between the two is shown by a dotted line in Figures 13 and 14.

[0077] The outer circumferential 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. 20 is 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 it is made smaller, the opening of the liquid flow path groove 14a in at least a part of the outer circumferential liquid flow path section 14 is not closed by the outer circumferential liquid flow path section 24 but is open, making it easier for condensed liquid to enter and steam to exit, thereby allowing for smoother movement of the working fluid.

[0078] In this embodiment, the peripheral liquid flow path section 24 of the second sheet 20 is configured to have a flat surface, but is not limited thereto, and liquid flow path grooves may be provided similarly to the peripheral liquid flow path section 14. In this case, the liquid flow path grooves of the first sheet and the liquid flow path grooves of the second sheet are overlapped to form the condensed liquid flow path 3.

[0079] As explained in the first sheet in this embodiment, the peripheral liquid flow path portion 24 does not necessarily have to be provided, and the peripheral liquid flow path portion 24 may not be provided.

[0080] 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.

[0081] 13 to 16, 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 circumferential liquid flow path section 24. The inner liquid flow path section 15 in this embodiment is a convex ridge extending with a curved portion, and is arranged at intervals in a direction different from the extension direction of the multiple (five in this embodiment) inner liquid flow path sections 25, and is disposed between the steam flow path grooves 26. In this embodiment, each inner liquid flow path portion 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 to form the condensate liquid flow paths 3. When no grooves for forming the condensate flow paths 3 are 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 thickness obtained by subtracting the depth G of the liquid flow path grooves 15a (see FIG. 8(a)) from the thickness of the first sheet 10. This makes it possible to prevent breakage (tear) on the second sheet side in the vapor chamber.

[0082] In this embodiment, the inner liquid flow path section 25 of the second sheet 20 is configured to have a flat surface, but is not limited thereto, and liquid flow path grooves may be provided similarly to the inner peripheral liquid flow path section 15. In this case, the liquid flow path grooves of the first sheet and the liquid flow path grooves of the second sheet are overlapped to form the condensed liquid flow path 3.

[0083] The width E20 of the inner liquid flow path section 25 shown in Figures 14 and 15 is not particularly limited, and may be the same as or different from the width E10 of the inner liquid flow path section 15 of the first sheet 10. 10 and width E 20is the same as. Width E 20 and width E 10 If the width E is different from the width E, the effect of misalignment during joining can be reduced. 20 Width E 10 If it is made smaller, the opening of the liquid flow path groove 15a in at least a part of the inner liquid flow path section 15 is not closed by the inner liquid flow path section 25 but is open, making it easier for condensed liquid to enter and for generated steam to exit, thereby allowing the working fluid to move more smoothly.

[0084] 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 a vapor state and a condensed liquid state moves, and constitutes a part of the steam flow path 4. Fig. 14 shows the shape of the steam flow path groove 26 in a plan view, and Fig. 15 shows the cross-sectional shape of the steam flow path groove 26.

[0085] As can be seen from these figures, the steam flow path groove 26 is formed as a groove having a curved portion 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 groove 26 in this embodiment is a groove 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. A plurality of steam flow path grooves 26 (six in this embodiment) are arranged in a direction different from the direction in which the steam flow path grooves 26 extend. Therefore, as can be seen from Fig. 14, the second sheet 20 has a shape in which convex ridges are formed with the inner liquid flow path sections 25 as convex portions and concave ridges are formed with the steam flow path grooves 26 as concave portions, and these concave and convex portions are repeated. Here, since the steam flow passage groove 26 is a groove, its cross-sectional shape has a bottom and an opening located on the opposite side facing the bottom.

[0086] The steam flow path groove 26 is preferably disposed at a position where, when combined with the first sheet 10, it overlaps with the steam flow path groove 16 of the first sheet 10 in the thickness direction. In this way, the steam flow path groove 16 and the steam flow path groove 26 can form the steam flow path 4. Figures 14 and 15 show H 20The 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 effect of misalignment during joining can be reduced. 20 Width H 10 If it is made larger, the opening of the liquid flow path groove 15a in at least a part of the inner liquid flow path section 15 is not closed 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 Fig. 15, 20 The depth of the steam flow passage groove 26 indicated by is preferably 10 μm or more and 300 μm or less.

[0087] Here, the steam flow passage groove 26 is preferably configured so that when the steam flow passage 4 is formed by combining with the first sheet 10 as described later, the width of the steam flow passage 4 is larger than its height (size in the thickness direction). 20 I 20 The aspect ratio expressed by the value obtained by dividing the ratio by 1 is preferably 4.0 or more, and more preferably 8.0 or more.

[0088] 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 with a semi-elliptical bottom.

[0089] The steam flow passage communication grooves 27 are grooves that, in combination with the steam flow passage communication grooves 17 of the first sheet 10, form a passage that communicates the ends of the multiple steam flow passages 4 formed by the steam flow passage grooves 26. This allows the movement of the working fluid that occurs in the steam flow passages 4 in the direction in which the inner liquid flow passage section 25 extends to be well balanced. In addition, the working fluid in the steam flow passages 4 is equalized, the steam is transported over a wider area, and many condensate flow passages 3 can be efficiently utilized, making it possible to more smoothly move the working fluid.

[0090] 14 and 16, the steam flow path communication groove 27 in this embodiment is formed between both ends in the extending direction of the inner liquid flow path section 25 and both ends in the extending direction of the steam flow path groove 26 and the outer circumferential liquid flow path section 24. Also, Fig. 16 shows a cross section perpendicular to the communicating direction of the steam flow path communication groove 27.

[0091] Figures 14 and 16 show 20 The width of the steam flow passage communicating groove 27 shown in FIG. 1 is not particularly limited, and the width J of the steam flow passage communicating groove 17 of the first sheet 10 is 10 may be the same as the width J 10 It may be different from the width J. 20 Width J 10 When the opening of the liquid flow path groove 14a is larger than this, in at least a portion of the outer peripheral liquid flow path portion 14 of the first sheet 10, the opening of the liquid flow path groove 14a is positioned to form part of the steam flow path 4, making it easier for condensed liquid to enter and for generated steam to exit, thereby enabling the working fluid to move more smoothly.

[0092] Width J 20 The size of is preferably in the range of 100 μm to 1000 μm. 20 The depth of the steam flow passage communication groove 27 indicated by is preferably 10 μm or more and 300 μm or less.

[0093] In this embodiment, the cross-sectional shape of the steam flow passage communication groove 27 is semi-elliptical, but is not limited to this and may be quadrangular such as square, rectangle, or trapezoid, triangular, semicircular, or having a semicircular bottom or a semi-elliptical bottom.

[0094] In addition, in this embodiment, the second sheet 20 has curved portions 28c which are portions where the extension directions of the outer circumferential liquid flow path portion 24, the inner liquid flow path portion 25, and the steam flow path groove 26 change. That is, as can be seen from Fig. 14, the second sheet 20 has straight portions 28a where the outer circumferential liquid flow path portion 24, the inner liquid flow path portion 25, and the steam flow path groove 26 extend linearly in the x direction, straight portions 28b where the outer circumferential liquid flow path portion 24, the inner liquid flow path portion 25, and the steam flow path groove 26 extend linearly in the y direction, and curved portions 28c which connect the outer circumferential liquid flow path portion 24, the inner liquid flow path portion 25, and the steam flow path groove 26 at the straight portions 28a and 28b. Therefore, one end of the curved portion 28c is connected to one straight portion 28a and the other end is connected to the other straight portion 28b, and the outer peripheral liquid flow path portion 24, the inner liquid flow path portion 25, and the steam flow path groove 26 are curved so that the flow changes direction from the x direction to the y direction and from the y direction to the x direction.

[0095] As can be seen from FIG. 14, in the curved portion 28c of this embodiment, the configuration of the outer circumferential liquid flow path portion 24, the inner liquid flow path portion 25, and the steam flow path grooves 26 can be considered to be similar to that of the curved portion 18c of the first sheet 10 described above.

[0096] Next, a description will be given of the structure when the first sheet 10 and the second sheet 20 are combined to form the vapor chamber 1. This description will provide a better understanding of the arrangement, size, shape, etc. of each component of the first sheet 10 and the second sheet 20. Fig. 17 shows a cross section of the vapor chamber 1 cut in the thickness direction along the y direction indicated by XV-XV in Fig. 1(a). This figure is a combination of the diagram of the first sheet 10 shown in Fig. 4 and the diagram of the second sheet 20 shown in Fig. 15, showing the cross section of the vapor chamber 1 at this location. FIG. 18 shows an enlarged view of the portion indicated by XVI in FIG. Fig. 19 shows a cross section of the vapor chamber 1 cut in the thickness direction along the x direction indicated by XVII-XVII in Fig. 1(a). This figure shows the cross section of the vapor chamber 1 at this portion by combining the diagram shown in Fig. 5(b) of the first sheet 10 and the diagram shown in Fig. 16 of the second sheet 20.

[0097] 1(a), 1(b) and 17 to 19, 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 overlap, and the injection portion 12 of the first sheet 10 and the injection portion 22 of the second sheet 20 overlap.

[0098] By laminating the first sheet 10 and the second sheet 20 in this manner, the components provided in the main body 11 and the main body 21 are arranged as shown in Figures 17 to 19. Specifically, they are as follows.

[0099] The vapor chamber 1 of this embodiment is particularly effective when it is thin. 0 The thickness of the vapor chamber 1 shown in is 1 mm or less, more preferably 0.4 mm or less, and even more preferably 0.2 mm or less. By making it 0.4 mm or less, in electronic devices in which the vapor chamber 1 is installed, it is often possible to install the vapor chamber inside the electronic device without processing (e.g., forming a groove, etc.) to form a space in which the vapor chamber is to be installed. And according to this embodiment, even such a thin vapor chamber has high strength and is resistant to deformation while maintaining thermal performance.

[0100] Meanwhile, the outer peripheral joining portion 13 of the first sheet 10 and the outer peripheral joining portion 23 of the second sheet 20 are arranged so as to overlap each other, and are joined together by a joining means such as diffusion bonding or brazing. As a result, an enclosed space 2 is formed between the first sheet 10 and the second sheet 20.

[0101] 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 with 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 so as 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.

[0102] Here, it is preferable that the cross-sectional shape of the condensate flow path 3 is flattened in accordance with the thinning of the vapor chamber 1. This can increase the capillary force and facilitate smoother movement of the condensate, thereby making it possible to maintain a high level of heat transport capacity. More specifically, it is preferable that the ratio (aspect ratio) of the width of the condensate flow path 3 divided by the height is greater than 1.0 and equal to or less than 4.0. At this time, the width of the condensed liquid flow path 3 is the width F of the liquid flow path groove 15a in this embodiment. 1 However, the width is preferably 10 μm or more and 300 μm or less. If the width is less than 10 μm, the flow path resistance increases and the transport capacity may decrease. On the other hand, if the width is more than 300 μm, the capillary force decreases and the transport capacity may decrease. In addition, the height of the condensate flow path 3 is preferably 5 μm or more and 200 μm or less, in accordance with the depth G of the liquid flow path groove 15a in this embodiment. This allows the capillary force of the condensate flow path required 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.

[0103] The cross-sectional shape of the condensate flow channel 3 is semi-elliptical due to the cross-sectional shapes of the liquid flow channel grooves 14a and 15a, but is not limited thereto and may be a square, a rectangle, a trapezoid or other quadrangle, a triangle, a semicircle, a semicircle with a bottom, a semi-ellipse with a bottom, or a combination of these. It may also be crescent-shaped.

[0104] In this embodiment, liquid flow path grooves 14a and 15a are provided only in first sheet 10, so 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 each other to form a condensate flow path, and the height of the condensate flow path corresponds to the sum of the depths of both liquid flow path grooves.

[0105] In this way, when liquid flow path grooves are provided in the first sheet and the second sheet and then stacked to form a condensate flow path, the condensate flow path can be configured as shown in Figures 20(a) to 20(c). The example in FIG. 20(a) is an example in which the liquid flow passage grooves of the first sheet and the second sheet are the same width and are disposed at the same positions. 20(b) is an example in which the width of the liquid flow channel in the second sheet is made larger than that of the first sheet, and the positions of the liquid flow channel are the same. In this example, a protrusion is formed in the condensate flow channel as shown by P, which improves the capillary force and increases the force that moves the condensate (the supply force of the condensate). 20(c) is an example in which the liquid flow channel grooves of the first sheet and the second sheet have the same width, but are arranged at offset positions. In this example as well, a protrusion is formed in the condensate flow channel as indicated by P, which improves the capillary force and increases the force that moves the condensate (the force that supplies the condensate).

[0106] As described above, the condensate flow passage 3 is formed with the communication opening 14c and the communication opening 15c. This allows the multiple condensate flow passages 3 to communicate with each other, and the condensate is uniformly distributed, allowing efficient movement of the condensate. Furthermore, the communication openings 14c and 15c, which are adjacent to the steam flow passage 4 and communicate the steam flow passage 4 with the condensate flow passage 3, can smoothly move the condensate generated in the steam flow passage 4 to the condensate flow passage 3, and can smoothly move the steam generated in the condensate flow passage 3 to the steam flow passage 4, allowing the working fluid to move quickly.

[0107] Moreover, the condensate flow path 3 formed by the peripheral liquid flow path section 14 and the peripheral liquid flow path section 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 section 14 and the peripheral liquid flow path section 24 is preferably formed in a ring shape and extends around the circumference without being interrupted by other components. This can reduce factors that impede the movement of the condensate, allowing the condensate to move smoothly.

[0108] In this embodiment, as explained above, the condensate flow path is formed by providing a condensate flow path groove in the sheet, but instead, a means for generating capillary force may be separately disposed here to form the condensate flow path. For this purpose, for example, a so-called wick such as a mesh material, nonwoven fabric, stranded wire, or sintered metal powder may be disposed.

[0109] The opening of the steam flow passage groove 16 in the first sheet 10 and the opening of the steam flow passage groove 26 in the second sheet 20 overlap so as to face each other to form a flow passage, which becomes the steam flow passage 4. Here, it is preferable that the cross-sectional shape 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 makes it possible to maintain a high level of heat transport capacity. More specifically, the width W B , height H B In W B H B The aspect ratio, which is calculated by dividing the aspect ratio by the average particle diameter, is preferably 2.0 or more. From the viewpoint of ensuring a higher heat transport capacity, the aspect ratio is more preferably 4.0 or more.

[0110] As can be seen from FIG. 17 , the openings of the steam flow passage communication grooves 17 of the first sheet 10 and the openings of the steam flow passage communication grooves 27 of the second sheet 20 overlap to face each other, forming a flow passage, which connects the ends of the multiple steam flow passages 4 formed by the steam flow passage grooves 16 and the steam flow passage grooves 26, providing a flow passage for balancing the movement of the working fluid.

[0111] As described above, the shapes of the first sheet 10 and the second sheet form the condensate flow path 3 and the steam flow path 4 in the sealed space 2 of the vapor chamber 1. Fig. 18 shows a diagram focusing on the condensate flow path 3 and the steam flow path formed in the sealed space 2. 18, 21, etc., the vapor chamber 1 has a shape in which a plurality of condensate flow paths 3 are arranged between two vapor flow paths 4. This results in a configuration in which the condensate flow path 3, through which the condensate should mainly flow, and the steam flow path 4, through which the steam and condensate move, are separated and alternately arranged, which helps smooth movement of the working fluid.

[0112] The working fluid in the form of vapor and condensate moves through the vapor flow path 4 and the condensate flow path 3, and heat is efficiently transferred and diffused. On the other hand, the condensate moves efficiently through the condensate flow path 3, which is provided separately from the vapor flow path 4, by capillary force, and therefore it is possible to suppress the occurrence of dryout.

[0113] Furthermore, in the vapor chamber 1, two straight sections 6 in which the condensate flow path 3 and the vapor flow path 4 extend in different directions are connected by a curved section 7. By forming such a flow path, even if the vapor chamber is placed in an electronic device and there are restrictions on its placement, and it is not possible to form a flow path that is only linear, the curved section 7 makes it possible to efficiently transfer heat generated from the heat source to a remote location.

[0114] This curved portion 7 is formed by the curved portion 18c of the first sheet 10 and the curved portion 28c of the second sheet 20. Therefore, one end of the curved portion 7 is connected to one straight portion 6, and the other end is connected to the other straight portion 6, and the condensate flow path 3 and the steam flow path 4 are curved so that the flow direction changes from the x direction to the y direction and from the y direction to the x direction.

[0115] In this embodiment, the flow passage cross-sectional area (width in this embodiment) of the vapor flow passage 4 is made larger in the curved portion 7 than in the straight portion 6. This makes it possible to reduce the flow resistance in the curved portion 7 where the flow resistance increases due to the curvature of the vapor flow passage 4, and reduces the flow resistance in the vapor chamber as a whole, which makes the movement of the working fluid smoother and increases the heat transport capacity. In this case, the flow passage cross-sectional area of ​​the vapor flow passage 4 in the curved portion 7 may be constant at least within the range of the curved portion 7. This makes it possible to reduce the flow loss of the working fluid due to the expansion and contraction of the flow passage cross-section. Here, the "cross-sectional area of ​​a flow channel" refers to the cross-sectional area of ​​the flow channel in a plane perpendicular to the direction in which the flow channel extends.

[0116] The means, degree and concept of increasing the flow passage cross-sectional area (width in this embodiment) of the steam flow passage 4 in the curved portion 7 in this manner are similar to those explained for the curved portion 18c of the first sheet 10 described above.

[0117] 21, in the curved portion 7 of this embodiment, the condensate flow path 3 and the steam flow path 4 are configured such that the radius of curvature of the outer steam flow path is larger than the radius of curvature of the inner steam flow path in the direction in which these flow paths are arranged.

[0118] In this embodiment, the grooves are curved to draw concentric arcs. However, the center positions of the arcs may be offset. Furthermore, the curved portion 7 is configured such that the radius of curvature of each flow groove increases as the length of each flow groove increases.

[0119] When multiple curved flow paths are arranged in a vapor chamber, the flow path length is shorter on the inside and longer on the outside, resulting in a large difference in flow resistance between the inside and outside. This difference in flow resistance causes the working fluid movement balance to be poor in the vapor chamber, which is one of the reasons why sufficient heat transport capacity cannot be exerted. In contrast, by using a configuration with the above-mentioned radius of curvature, it is possible to reduce the difference in flow resistance between the inside and outside, especially in the vapor flow path 4. This improves the balance of the movement of the working fluid and also increases the heat transport capacity.

[0120] However, the present invention is not limited to this, and the radius of curvature of the plurality of steam flow paths 4 at the curved portion 7 may be the same, following the example of FIG.

[0121] In addition, in the curved portion 7, the communication openings 14c and 15c (see Fig. 6 and Fig. 8(b)) provided in the walls 14b and 15b separating the condensate flow path 3 and the steam flow path 4 can be configured to have a pitch different from that of the straight portion 6. The pitch of the communication openings in the curved portion may be larger or smaller than the pitch of the curved portions in the straight portion. The form to be adopted can be determined by comprehensively determining the form that can reduce the flow resistance, taking into consideration the effects of the overall shape of the vapor chamber, the position of the heat source, etc. Alternatively, in the curved portion 7, the communication openings 14c and 15c may not be provided in the walls 14b and 15b separating the condensate flow path 3 and the steam flow path 4. In a configuration in which the pitch of the communication openings in the curved portion is made larger than the pitch of the communication openings in the straight portion, the working fluid flowing through the steam passage 4 can be prevented from entering the communication openings 14c and 15c at the curved portion 7. In the curved portion 7, the working fluid moving through the steam passage 4 is forced to flow directly into the communication openings 14c and 15c in the direction of its flow, so that the steam tends to enter the condensate passage 3 and the flow resistance tends to increase due to the unevenness of the communication openings 14c and 15c. In response to this, by increasing the pitch of the communication openings 14c and 15c that contact the steam passage 4 at the curved portion 7 or by eliminating the communication openings 14c and 15c that contact the steam passage 4, it is possible to prevent such an increase in flow resistance, further reducing the difference in flow resistance for each steam passage 4, improving the balance of the movement of the working fluid, and increasing the heat transport capacity. On the other hand, when the pitch of the communication openings in the curved section is smaller than that of the straight section, the steam flowing through the steam flow groove (steam flow path) has more opportunities to strongly hit the wall surface in the curved section, which tends to make it easier to condense. In this case, by making the pitch of the communication openings in the curved section smaller than that of the straight section, the number of communication openings can be increased, and the condensate can be smoothly introduced into the liquid flow groove (condensate flow path), making it possible to prevent the steam flow path from being blocked by the condensate. This can prevent an increase in flow resistance, further reduce the difference in flow resistance between the steam flow grooves (steam flow paths), improve the balance of the movement of the working fluid, and may increase the heat transport capacity.

[0122] Alternatively, instead of the pitch, the length of the wall between adjacent communication openings in the curved portion (the length in the direction along the flow path) may be greater or smaller than the length of the wall in the straight portion. In this case, the length of the walls in the curved portion does not need to be constant and may be different for each wall. In this case, the relationship between the length of the walls in the curved portion and the length of the walls in the straight portion is determined by the relationship between the average lengths of the walls in the respective portions.

[0123] On the other hand, as shown in Figure 1, the inner surfaces 10a, 20a of the injection parts 12 and 22 overlap each other so that they face each other, and the opening on the opposite side to 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, and an injection flow path 5 is formed that connects the outside to the hollow portion between the main body 11 and the main body 21 (the condensate flow path 3 and the steam flow path 4). However, after the working fluid is injected from the injection passage 5 into the sealed space 2, the injection passage 5 is closed, so that in the final form of the vapor chamber 1, the sealed space 2 does not communicate with the outside.

[0124] 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.

[0125] The vapor chamber as described above can be produced, for example, as follows.

[0126] A sheet made of the material constituting the first sheet 10 and having the outer circumferential shape of the first sheet 10, and a sheet made of the material constituting the second sheet 20 and having the outer circumferential shape of the second sheet 20 are prepared. The above-described liquid flow path grooves 14a, liquid flow path grooves 15a, vapor flow path grooves 16, vapor flow path grooves 26, vapor flow path communication grooves 17, and vapor flow path communication grooves 27 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 penetrating the thickness direction.

[0127] Next, the etched sheet having the shape of the first sheet 10 and the etched sheet having the shape of the second sheet 20 are overlapped with the inner surface 10a and the inner surface 20a facing each other, and temporarily fixed. The method of temporary fixing is not particularly limited, but examples include resistance welding, ultrasonic welding, and adhesion with an adhesive. After the temporary fixing, the sheets are bonded permanently by diffusion bonding. Bonding may be used instead of diffusion bonding. However, in the case of a thin vapor chamber as in this embodiment, the flow path is narrow, so if brazing is used with a brazing material, there is a risk that the brazing material will enter the flow path. In addition, since a strong capillary force acts on the flow path as described above, there is a risk that the brazing material will spread over a wide area of ​​the flow path. From this perspective, bonding by welding such as diffusion bonding or ultrasonic bonding, which does not cause such problems, is preferable.

[0128] After bonding, a vacuum is drawn through the formed injection flow path 5 to reduce the pressure inside the hollow portion. After that, the working fluid is injected through the injection flow path 5 into the reduced pressure hollow portion, and the working fluid is placed in the hollow portion. Then, the injection flow path 5 is closed by melting the injection portions 12 and 22 with a laser or by crimping. This forms the sealed space 2, inside which the working fluid is stably held, forming the vapor chamber 1.

[0129] Next, the action of the vapor chamber 1 when it is activated will be described. Fig. 22 shows a schematic diagram of the vapor chamber 1 disposed inside a portable terminal 40, which is one form of electronic device. Here, the vapor chamber 1 is shown by a dotted line because it is disposed inside a housing 41 of the portable terminal 40. Such a portable terminal 40 is configured with a housing 41 that contains various electronic components, and a display unit 42 that is exposed so that images can be seen to the outside through an opening of the housing 41. And, as one of these electronic components, an electronic component 30 to be cooled by the vapor chamber 1 is disposed inside the housing 41.

[0130] The vapor chamber 1 is installed in the housing of a portable terminal or the like, and is attached to an electronic component 30, which is an object to be cooled, such as a CPU. 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.

[0131] Fig. 23 is a diagram for explaining the behavior of the working fluid. For ease of explanation, this diagram is taken from the same perspective as Fig. 21, and focuses on the condensate flow path 3 and the steam flow path 4 formed in the sealed space 2. When the electronic components 30 generate heat, the heat is transferred by thermal conduction within the first sheet 10, and the condensate present in the sealed space 2 near the electronic components 30 receives the heat. The condensate absorbs the heat and evaporates, thereby cooling the electronic components 30.

[0132] 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. 23, or may move in a direction away from the electronic component 30, which is a heat source, without vibrating, although this is not shown. At this time, the steam flow path 4 includes the curved portion of the curved portion 7, but because the curved portion 7 has the above-mentioned configuration, even if the flow path lengths are different, the flow resistance is reduced and well-balanced, and the working fluid moves smoothly through the steam flow path 4. This makes it possible to exhibit high heat transport capacity. During this movement of the working fluid, 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, which absorb heat from the vapor, transfer the heat to the housing of the portable terminal device in contact with their outer surfaces 10b and 20b, and the heat is finally released to the outside air. Then, the working fluid from which heat has been absorbed while moving through the vapor flow path 4 condenses and becomes a liquid.

[0133] A part of the condensate generated in the steam flow passage 4 moves from the communicating openings etc. to the condensate flow passage 3. Since the condensate flow passage 3 in this embodiment is provided with the communicating openings 14c and 15c, the condensate is distributed to the plurality of condensate flow passages 3 through the communicating openings 14c and 15c.

[0134] 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. 23. Then, it is vaporized again by the heat from the heat source, electronic component 30, and the above process is repeated.

[0135] As described above, according to the vapor chamber 1, the movement of the working fluid in the vapor flow path and the strong capillary force in the condensate flow path make the movement of the working fluid smooth and excellent, thereby improving the heat transport capacity. Furthermore, by forming a flow path in the vapor chamber 1 having a curved portion 7, even when the vapor chamber is placed in an electronic device and there are restrictions on its placement, making it impossible to form a flow path that is only in a straight line, the heat generated from the heat source can be efficiently transferred to a remote location. Furthermore, as described above, the curved section 7 is configured to reduce the flow resistance in the multiple steam flow paths 4 and, if necessary, to reduce the difference in flow resistance, so that the working fluid can be moved in a balanced manner and the heat transport capacity can be increased.

[0136] 24 to 31 are diagrams illustrating the vapor chamber 201 according to the second embodiment. Fig. 24 is an external perspective view of the vapor chamber 201, and Fig. 25 is an exploded perspective view of the vapor chamber 201.

[0137] 24 and 25, the vapor chamber 201 has a first sheet 210, a second sheet 220, and a third sheet 230. The first sheet 210, the second sheet 220, and the third sheet 230 are stacked and joined (diffusion bonding, brazing, etc.) to form a hollow space surrounded by the first sheet 210, the second sheet 220, and the third sheet 230 between the first sheet 210 and the second sheet 220. The working fluid is sealed in this hollow space to form the sealed space 202.

[0138] In this embodiment, the first sheet 210 is a sheet-like member as a whole. The first sheet 210 is composed of flat surfaces on both sides, and has an inner surface 210a, an outer surface 210b opposite to the inner surface 210a, and a side surface 210c that spans the inner surface 210a and the outer surface 210b to form a thickness.

[0139] The first sheet 210 includes a main body 211 and an injection part 212. The main body 211 is a sheet-like part that forms an enclosed space through which the working fluid moves, and in this embodiment, is a rectangle with arcuate corners (so-called R) in plan view. Injection portion 212 is a portion where working fluid is injected into the sealed space formed by first sheet 210, second sheet 220, and third sheet 230, and in this embodiment, is a sheet-like shape that is rectangular in plan view and protrudes from the L-shaped body 211 in plan view. In this embodiment, injection portion 212 of first sheet 210 has flat surfaces on both the inner surface 210a side and the outer surface 210b side.

[0140] In this embodiment, the second sheet 220 is a sheet-like member as a whole. The second sheet 220 is composed of flat surfaces on both sides, and includes an inner surface 220a, an outer surface 220b opposite to the inner surface 220a, and a side surface 220c that spans the inner surface 220a and the outer surface 220b to form a thickness.

[0141] The second sheet 220 also has a body 221 and an injection portion 222 .

[0142] In this embodiment, the third sheet 230 is a sheet sandwiched and overlapped between the inner surface 210a of the first sheet 210 and the inner surface 220a of the second sheet 220, and a structure for moving the working fluid is formed in the main body 231. Fig. 26 shows a plan view of the third sheet 230. Fig. 26(a) shows the surface overlapping the second sheet 220, and Fig. 26(b) shows the surface overlapping the first sheet 210. Fig. 27 shows a cut surface along the line XXIV-XXIV in Fig. 26(a), and Fig. 28 shows a cut surface along the line XXV-XXV in Fig. 26(a).

[0143] The third sheet 230 includes a main body 231 and an injection portion 232. The main body 231 is a sheet-like portion that forms a sealed space in which the working fluid moves, and in this embodiment, is L-shaped with a curved portion in a plan view. Injection portion 232 is a portion where working fluid is injected into the sealed space formed by first sheet 210, second sheet 220, and third sheet 230, and in this embodiment, is a sheet-like shape that is rectangular in plan view and protrudes from main body 231 that is L-shaped in plan view. Injection portion 232 has injection groove 232a formed on the surface side that overlaps first sheet 210. Injection groove 232a can be considered to be similar to injection groove 22a described above.

[0144] The main body 231 includes an outer periphery joining portion 233 , an outer periphery liquid flow path portion 234 , an inner liquid flow path portion 235 , a steam flow path slit 236 , and a steam flow path connecting groove 237 .

[0145] The outer periphery bonding portion 233 is a portion formed along the outer periphery of the main body 231. One surface of the outer periphery bonding portion 233 is overlapped and bonded (diffusion bonding, brazing, etc.) to the surface of the first sheet 210, and the other surface is overlapped and bonded (diffusion bonding, brazing, etc.) to the surface of the second sheet 220. As a result, a hollow portion surrounded by the first sheet 210, the second sheet 220, and the third sheet 230 is formed, and the working fluid is sealed in this hollow portion to form the sealed space 202. The outer peripheral joint 233 can be considered to be similar to the outer peripheral joint 13 described above.

[0146] The peripheral liquid flow path section 234 functions as a liquid flow path section and is a part 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 234 is formed along the inside of the peripheral joint section 233 of the main body 231, and is provided so as to be annular along the outer periphery of the sealed space 202. A liquid flow path groove 234a is formed on the surface of the peripheral liquid flow path section 234 that faces the second sheet 220. In this embodiment, the liquid flow path groove 234a is provided only on the surface that faces the second sheet 220, but in addition to this, a liquid flow path groove may also be provided on the surface that faces the first sheet 210. The outer circumferential liquid flow passage portion 234 and the liquid flow passage grooves 234a provided therein can be considered to be similar to the outer circumferential liquid flow passage portion 14 and the liquid flow passage grooves 14a described above.

[0147] The inner liquid flow path section 235 also functions as a liquid flow path section, and is a portion that constitutes a part of the condensed liquid flow path 3 through which the working fluid passes when condensed and liquefied. The inner liquid flow path section 235 is formed to extend with a curved portion inside the ring of the annular outer peripheral liquid flow path section 234 in the main body 231. A plurality of (five in this embodiment) inner liquid flow path sections 235 are arranged in a direction different from the extending direction, and are disposed between the steam flow path slits 236.

[0148] A liquid flow path groove 235a, which is a groove parallel to the extension direction of the inner liquid flow path section 235, is formed on the surface of the inner liquid flow path section 235 facing the second sheet 220. The inner liquid flow path section 235 and the liquid flow path groove 235a can be considered to be similar to the above-mentioned inner liquid flow path section 15 and the liquid flow path groove 15a. In this embodiment, the liquid flow path grooves 235 a are provided only on the surface facing the second sheet 220 , but in addition to this, liquid flow path grooves may also be provided on the surface facing the first sheet 210 .

[0149] The steam flow passage slit 236 is a portion where the working fluid in the vapor state and the condensed liquid state moves, and is a slit that constitutes the steam flow passage 4. The steam flow passage slit 236 is constituted by a slit having a curved portion that is formed inside the ring of the annular outer peripheral liquid flow passage section 234 in the main body 231. More specifically, the steam flow passage slit 236 in this embodiment is a slit that is formed between adjacent inner liquid flow passage sections 235 and between the outer peripheral liquid flow passage section 234 and the inner liquid flow passage section 235. Therefore, the steam flow passage slit 236 penetrates the third sheet 230 in the thickness direction (z direction). A plurality of (six in this embodiment) steam flow passage slits 236 are arranged in a direction different from the extending direction. Therefore, as can be seen from Fig. 27, the third sheet 230 has a shape in which the outer peripheral liquid flow passage portion 234, the inner liquid flow passage portion 235, and the steam flow passage slits 236 are alternately repeated.

[0150] Such a steam flow passage slit 236 can be considered to be similar to the aspect of the steam flow passage 4 formed by combining the steam flow passage groove 16 and the steam flow passage groove 26 described above.

[0151] In this embodiment, the cross-sectional shape of the steam flow path slit 236 is formed by overlapping parts of an ellipse, with the center in the thickness direction protruding, but is not limited to this and may be other shapes such as a square, rectangle, trapezoid or other quadrilateral, a triangle, a semicircle, a crescent, or a combination of these.

[0152] The steam flow passage communication groove 237 is a groove that forms a flow passage that communicates the multiple steam flow passage slits 236. This makes it possible to balance the movement of the working fluid that occurs in the steam flow passage in the direction in which the inner liquid flow passage section 235 extends. This also makes it possible to equalize the working fluid in the steam flow path, transport the steam over a wider area, and efficiently utilize the condensate flow paths defined by the many liquid flow path grooves 234a and 235a.

[0153] The steam flow path communication groove 237 in this embodiment is formed between both ends in the direction in which the inner liquid flow path section 235 extends and both ends in the direction in which the steam flow path slits 236 extend, and the outer circumferential liquid flow path section 234. The steam flow path communication groove 237 only needs to be able to communicate with adjacent steam flow path slits 236, and the shape thereof is not particularly limited, but it can be considered to be similar to a flow path formed by overlapping the above-mentioned steam flow path communication groove 17 and steam flow path communication groove 27.

[0154] The third sheet 230 also has a straight portion 238a, a straight portion 238b, and a curved portion 238c so that the condensate flow path 3 and the vapor flow path 4 have straight portions and curved portions in the sealed space 202 of the vapor chamber 201. The concepts of these straight portions and curved portions are the same as those explained so far.

[0155] Such a third sheet 230 can be produced by etching each side separately, etching both sides simultaneously, pressing, cutting, or the like.

[0156] Figures 29 to 31 are diagrams for explaining the structure when the first sheet 210, the second sheet 220, and the third sheet 230 are combined to form the vapor chamber 201. Figure 29 shows a cross section taken along the line indicated by XXVI-XXVI in Figure 24, and Figure 30 shows an enlarged view of a portion of Figure 29. Also, Figure 31 shows a cross section taken along the line indicated by XXVIII-XXVIII in Figure 24.

[0157] As can be seen from Fig. 24 and Fig. 29 to Fig. 31, the first sheet 210, the second sheet 220, and the third sheet 230 are arranged so as to be overlapped and joined to form the vapor chamber 201. At this time, the inner surface 210a of the first sheet 210 and one surface of the third sheet 230 (the surface on the side on which the liquid flow path grooves 234a and 235a are not arranged) are arranged to face each other, and the inner surface 220a of the second sheet 220 and the other surface of the third sheet 230 (the surface on which the liquid flow path grooves 234a and 235a are arranged) are arranged to face each other. In the same manner, the injection section 212, the injection section 222, and the injection section 232 of each sheet are also overlapped.

[0158] As a result, a sealed space 202 surrounded by the first sheet 210, the second sheet 220, and the third sheet 230 is formed between the first sheet 210 and the second sheet 220. A condensate flow path 3 and a steam flow path 4 are formed in this sealed space 202. The same concept as that of the vapor chamber 1 described above can be applied to the configurations of the condensate flow path 3 and the steam flow path 4 in the sealed space 202.

[0159] In the above embodiment, the vapor chamber has been described as having a curved portion at the intersection when two straight portions intersect at 90 degrees to form an L-shape. However, the form of the curve is not limited to this, and the above-described curved portion can be applied to other forms. For example, the curved portion can be applied to each of the intersections when two straight portions extend in a direction intersecting a T-shape, when two straight portions extend in a direction intersecting a cross, when two straight portions intersect at an acute angle (an angle smaller than 90 degrees) to form a V-shape, and when two straight portions intersect at an obtuse angle (an angle larger than 90 degrees) to form a V-shape. [Explanation of symbols]

[0160] 1 Vapor Chamber 2 Closed space 3 Condensate flow path 4 Steam flow path 10 First Sheet 11 Main unit 12 Injection part 13 Peripheral joint 14 Peripheral liquid flow path section 14a Liquid flow groove 14c Communication opening 15 Inner liquid flow path section 15a Liquid flow groove 15c Communication opening 16 Steam flow channel 17 Steam flow passage connecting groove 20 Second Sheet 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 27 Steam flow passage connecting groove 230 Third Sheet 236 Steam flow passage slit

Claims

[Claim 1] A vapor chamber in which a working fluid is sealed in a 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 plurality of steam flow paths having a flow path cross-sectional area larger than that of the condensate flow path, through which the working fluid moves in a state of vapor and condensate; a linear portion in which the plurality of condensate flow paths and the plurality of steam flow paths extend linearly; a curved portion connected to the straight portion and in which the direction in which the plurality of condensate flow paths and the plurality of steam flow paths extend changes, A vapor chamber configured so that the vapor flow path in the curved portion has a larger flow path cross-sectional area than the vapor flow path in the straight portion.

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