Evaporation section structure and heat transport member equipped with the evaporation section structure

Abstract

Provided is an evaporator structure with excellent evaporation characteristics of liquid-phase working fluid sealed in a container.　An evaporator structure for a heat transport member in which a container having an interior space with a working fluid sealed therein is provided with: an evaporator in which the working fluid in a liquid phase undergoes a phase change from the liquid phase to a gas phase; and a condenser that is disposed at a different site from the evaporator and in which the working fluid in the gas phase undergoes a phase change from the gas phase to the liquid phase. A sintered body layer obtained by sintering metal-containing raw material particles is provided on the inner surface of the evaporator of the container. The sintered body layer having an average thickness of n comprises a first portion that is n / 2 of the region on the inner side of the container and a second portion that is n / 2 of the region on the interior space side. The porosity of the first portion is smaller than the porosity of the second portion.

Description

Technical Field

[0001] The present invention relates to an evaporation section structure that can impart excellent heat transport characteristics to a heat transport member by virtue of excellent evaporation characteristics of a liquid-phase working fluid enclosed in a container, and a heat transport member provided with the evaporation section structure.

Background Art

[0002] Electronic components such as semiconductor elements mounted on electric and electronic devices have an increased heat generation amount due to high-density mounting and the like accompanying high functionality, and in recent years, their cooling has become more important. As a cooling method for heat sources such as electronic components, a heat transport member provided with a container having an internal space filled with a working fluid may be used. In the heat transport member, the working fluid enclosed in the internal space of the container undergoes a phase change from a liquid phase to a gas phase in the evaporation section of the container, thereby receiving heat from the electronic component to be cooled, and undergoes a phase change from a gas phase to a liquid phase in the condensation section of the container, thereby releasing the heat received from the object to be cooled, thus cooling the object to be cooled.

[0003] In order to reflux the working fluid that has undergone a phase change from a gas phase to a liquid phase from the condensation section to the evaporation section, a wick structure having capillary force is provided from the condensation section to the evaporation section inside the container. Therefore, it is required that the wick structure has excellent evaporation characteristics of the liquid-phase working fluid refluxed from the condensation section in the evaporation section. As the wick structure, for example, a sintered body layer formed by sintering metal powder may be used.

[0004] As the sintered body layer formed by sintering metal powder, for example, a porous powder sintered body is formed, and then a raw material powder having a smaller particle size than the raw material powder constituting the powder sintered body is sintered in a state of being interposed between the powder sintered body and the inner wall surface of the container, whereby it has been proposed to fix the powder sintered body to the inner wall surface of the container to form a sintered powder layer (Patent Document 1).

[0005] Patent Document 1 describes a method for reducing thermal resistance between the sintered powder layer and the container in a heat pipe and improving the evaporation characteristics of the liquid-phase working fluid by bonding them metallically rather than mechanically. Furthermore, Patent Document 1 describes a wick structure with a two-layer structure consisting of a bonding layer formed from small raw material powder and a sintered powder layer formed from large raw material powder. This two-layer structure has different void sizes in the thickness direction, which allows for tightly spaced voids to obtain connection strength with the container while maintaining excellent fluidity of the liquid-phase working fluid.

[0006] However, in Patent Document 1, which describes a wick structure with a two-layer structure consisting of a bonding layer formed from small raw material powders and a sintered powder layer formed from large raw material powders, the porosity of the sintered powder layer formed from the large raw material powders is high, and excellent heat transfer properties cannot be obtained in the sintered powder layer. Therefore, in Patent Document 1, there was a need to improve the evaporation characteristics of the liquid phase working fluid in the evaporation section. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2000-055577 [Overview of the project] [Problems that the invention aims to solve]

[0008] In view of the above circumstances, the present invention aims to provide an evaporation section structure that is excellent in the evaporation characteristics of a liquid-phase working fluid sealed in a container, and a heat transport member equipped with the evaporation section structure. [Means for solving the problem]

[0009] The gist of the present invention is as follows: [1] A heat transport member comprising an evaporation section structure in which a container having an internal space containing a working fluid undergoes a phase change from liquid to gaseous phase, and a condensation section located separately from the evaporation section in which the gaseous working fluid undergoes a phase change from gaseous to liquid, A sintered body layer, in which raw material particles containing metal are sintered, is provided on the inner surface of the evaporation section of the container. An evaporation section structure wherein the sintered body layer, having an average thickness n, comprises a first portion which is an n / 2 region on the inner surface side of the container and a second portion which is an n / 2 region on the internal space side, and the porosity of the first portion is smaller than the porosity of the second portion. [2] The evaporation section structure according to [1], wherein the raw material particles are a mixture having first raw material particles having a predetermined average primary particle diameter and second raw material particles having a smaller average primary particle diameter than the first raw material particles. [3] The evaporation section structure according to [2], wherein the average primary particle diameter of the first raw material particles is 50 μm or more and 300 μm or less, and the average primary particle diameter of the second raw material particles is 1.0 nm or more and 10 μm or less. [4] The evaporation section structure according to [2] or [3], wherein the average primary particle diameter of the second raw material particles is 1.0 nm or more and 1000 nm or less. [5] The evaporation section structure according to any one of [2] to [4], wherein the ratio of the average primary particle diameter of the first raw material particles to the average primary particle diameter of the second raw material particles is 20 or more and 50,000 or less. [6] The evaporation section structure according to any one of [2] to [5], wherein the raw material particles contain 10 to 1000 parts by mass of the second raw material particles per 100 parts by mass of the first raw material particles. [7] The evaporation section structure according to any one of [2] to [6], wherein the first raw material particles include copper and / or copper alloy particles, and the second raw material particles include copper and / or copper alloy particles. [8] The evaporation structure according to any one of [1] to [7], wherein the average size of the voids in the second region is 1 μm or more and 200 μm or less. [9] The evaporation section structure according to any one of [1] to [8], wherein the average thickness n of the sintered body layer is 100 μm or more and 1.0 mm or less. A heat transport member having an evaporation section structure as described in any one of

[10] [1] to [9].

[11] The heat transport member described in

[10] , which is a vapor chamber.

[0010] The above-mentioned "evaporation section" is the part of the container to which the heat-generating element, which is the object to be cooled by the heat transport member, is thermally connected. The "porosity" in [1] above can be determined by observing the area ratio of voids in the cross-section of the evaporation section structure using a microscope such as a scanning electron microscope (SEM).

[0011] The evaporation section structure described in [2] above has a sintered body layer formed by sintering raw material particles, which are a mixture of first raw material particles and second raw material particles having a smaller average primary particle diameter than the first raw material particles. Since raw material particles with a smaller average primary particle diameter have a strong cohesive force, when these raw material particles are sintered, in the first region of the sintered body layer, which is the inner surface region of the container, the second raw material particles mainly aggregate to form a bulk sintered body, while in the second region, which is the internal space region, the second raw material particles mainly aggregate between the first raw material particles, resulting in a sintered body with numerous voids. [Effects of the Invention]

[0012] According to an embodiment of the evaporation section structure of the present invention, a sintered body layer with an average thickness n consists of a first region which is n / 2 of the inner surface of the container and a second region which is n / 2 of the inner surface of the internal space. Since the porosity of the first region is smaller than that of the second region, an evaporation section structure with excellent evaporation characteristics for the liquid-phase working fluid sealed in the container can be obtained. The reason why the evaporation section structure of the present invention has excellent evaporation characteristics for the liquid-phase working fluid is thought to be that the first region of the sintered body layer, which is the inner surface of the container, has excellent heat transfer properties, and the second region, which is the inner surface of the internal space, is a sintered body with many voids formed therein, thus acting as a starting point for evaporation of the liquid-phase working fluid; in other words, the second region is an evaporation-promoting structure. Furthermore, in the evaporation section structure of the present invention, having the first region and the second region reduces the thermal resistance between the container and the sintered body layer, resulting in an evaporation section structure with excellent evaporation characteristics. Furthermore, according to an embodiment of the evaporation section structure of the present invention, the sintered body layer is a sintered body of a mixture having first raw material particles having a predetermined average primary particle diameter and second raw material particles having a smaller average primary particle diameter than the first raw material particles, and the sintered body layer with an average thickness n consists of a first portion which is an n / 2 region on the inner surface side of the container and a second portion which is an n / 2 region on the internal space side, and because the porosity of the first portion is smaller than that of the second portion, the first portion of the sintered body layer, which is the inner surface side of the container, is a sintered body mainly composed of aggregated second raw material particles forming a bulk, thus having excellent heat transfer properties, and the second portion, which is the internal space side, is a sintered body with many voids formed, thus serving as the starting point for evaporation of the liquid phase working fluid, that is, the second portion has an evaporation promoting structure, and therefore the evaporation section structure has excellent evaporation characteristics for the liquid phase working fluid.

[0013] According to an embodiment of the evaporation section structure of the present invention, the average primary particle diameter of the first raw material particles is 50 μm or more and 300 μm or less, and the average primary particle diameter of the second raw material particles is 1.0 nm or more and 10 μm or less. As a result, excellent heat transfer performance is reliably obtained in the first region, which is the inner surface region of the container, and an evaporation-promoting structure is reliably obtained in the second region, which is the internal space region, thus reliably improving the evaporation characteristics of the liquid phase working fluid.

[0014] According to the aspect of the evaporation section structure of the present invention, since the ratio of the average primary particle diameter of the first raw material particles to the average primary particle diameter of the second raw material particles is 20 or more and 50000 or less, excellent heat transfer performance can be surely obtained in the first part which is the region on the inner surface side of the container, and an evaporation promotion structure can be surely obtained in the second part which is the region on the internal space side. Therefore, the evaporation characteristics of the liquid-phase working fluid are surely improved.

[0015] According to the aspect of the evaporation section structure of the present invention, since the average size of the voids in the second part is 1 μm or more and 200 μm or less, a more excellent evaporation promotion structure can be obtained. The average size of the voids can be specified by observing the sizes of a plurality of voids in the cross section of the evaporation section structure using a microscope such as a scanning electron microscope (SEM) and calculating the average value.

[0016] According to the aspect of the evaporation section structure of the present invention, since the average thickness n of the sintered body layer is 100 μm or more and 1.0 mm or less, while the liquid-phase working fluid is surely refluxed to the evaporation section, a vapor flow path through which the gas-phase working fluid flows is surely secured.

Brief Description of Drawings

[0017] [Figure 1] It is a side view showing the whole of a heat transport member provided with an evaporation section structure according to a first embodiment example of the present invention. [Figure 2] It is a perspective view explaining the outline of an evaporation section structure according to a first embodiment example of the present invention. [Figure 3] It is a cross-sectional view taken along the line A - A' of FIG. 2. [Figure 4] It is an explanatory view showing the details of an evaporation section structure according to a first embodiment example of the present invention. [Figure 5] It is a perspective view explaining the outline of an evaporation section structure according to a second embodiment example of the present invention. [Figure 6] It is a cross-sectional view taken along the line A - A' of FIG. 5. [Figure 7] It is a perspective view explaining the outline of an evaporation section structure according to a third embodiment example of the present invention. [Figure 8] This is a cross-sectional view taken along line A-A' in Figure 7. [Figure 9] This is a perspective view illustrating the outline of the evaporation section structure according to a fourth embodiment of the present invention. [Figure 10] This is a cross-sectional view taken along line A-A' in Figure 9. [Figure 11] This is a perspective view illustrating the outline of the evaporation section structure according to a fifth embodiment of the present invention. [Figure 12] This is a cross-sectional view taken along line A-A' in Figure 11. [Figure 13] This is a perspective view illustrating the outline of the evaporation section structure according to the sixth embodiment of the present invention. [Figure 14] This is a cross-sectional view taken along line A-A' in Figure 13. [Modes for carrying out the invention]

[0018] The evaporation section structure in the heat transport member according to the first embodiment of the present invention will be described in detail below. Figure 1 is a side view showing the entire heat transport member equipped with the evaporation section structure according to the first embodiment of the present invention. Figure 2 is a perspective view illustrating the outline of the evaporation section structure according to the first embodiment of the present invention. Figure 3 is a cross-sectional view taken along line A-A' in Figure 2. Figure 4 is an explanatory diagram showing the details of the evaporation section structure according to the first embodiment of the present invention.

[0019] As shown in Figure 1, the heat transport member 100 equipped with the evaporation section structure 1 according to the first embodiment of the present invention comprises a container 10 in which an internal space called a cavity 13 is formed by overlapping two opposing plate-like bodies, that is, one plate-like body 11 and the other plate-like body 12 facing the first plate-like body 11; a working fluid (not shown) sealed in the cavity 13; and a vapor passage provided in the cavity 13 through which the gaseous working fluid flows. The heat transport member 100 is formed by the container 10 with the cavity 13 formed inside, the working fluid, and the vapor passage. In Figure 1, a vapor chamber is used as the heat transport member 100 equipped with the evaporation section structure 1.

[0020] Container 10 is a thin, plate-shaped container having a flat portion 17 and a protrusion 16 that extends outward from the flat portion 17. The internal space of the protrusion 16 of container 10 is in communication with the internal space of the flat portion 17, and a cavity 13 of container 10 is formed from the internal spaces of the protrusion 16 and the flat portion 17. Therefore, the working fluid can flow between the internal space of the protrusion 16 and the internal space of the flat portion 17. The cavity 13 is a sealed space and is depressurized by a degassing process.

[0021] The shape of the container 10 is not particularly limited, but examples of heat transport members 100 include polygonal shapes such as squares, circular shapes, elliptical shapes, and shapes having straight and curved sections when viewed from above (viewed from a direction perpendicular to the flat surface 17 of the container 10).

[0022] The protrusion 16 of the container 10 is not provided with any heat exchange means such as heat dissipation fins. The heat transport member 100 is not provided with any heat exchange means such as heat dissipation fins on either the tip or the side of the protrusion 16. The protrusion 16 of the container 10 is the part to which the heat-generating element 200, which is the object to be cooled, is thermally connected, and the protrusion 16 functions as the heat receiving part of the heat transport member 100, that is, the evaporation part of the container 10. The heat-generating element 200 is thermally connected to the tip of the protrusion 16. In the evaporation part of the container 10, the liquid-phase working fluid undergoes a phase change to the gas phase by receiving heat from the heat-generating element 200. The heat-generating element 200 is not particularly limited and can be, for example, an electronic component such as a central processing unit mounted on a wiring board (not shown).

[0023] On the other hand, multiple heat dissipation fins 110, 110, 110... are erected on the flat surface 17 of the container 10, and the multiple heat dissipation fins 110, 110, 110... are thermally connected to the container 10. The heat dissipation fins 110 are arranged in parallel at predetermined intervals along the extending direction of the flat surface 17. The heat dissipation fins 110 are erected on both sides of the container 10, that is, on one plate-like body 11 and the other plate-like body 12. In Figure 1, multiple heat dissipation fins 110, 110, 110... are erected on the flat surface 17 of the container 10 to form a heat sink 120.

[0024] The portion of the container 10 to which the heat dissipation fins 110 are thermally connected functions as the heat dissipation section of the heat transport member 100, that is, the condensation section of the container 10. In the condensation section of the container 10, the working fluid in the gas phase undergoes a phase change to the liquid phase due to the heat exchange function of the heat exchange means, releasing latent heat.

[0025] From the above, the container 10, which has a cavity 13 that is an internal space in which the working fluid is sealed, includes an evaporation section in which the liquid-phase working fluid undergoes a phase change from the liquid phase to the gas phase, and a condensation section located in a different part from the evaporation section in which the gas-phase working fluid undergoes a phase change from the gas phase to the liquid phase. From the above, the heat transport member 100 has an evaporation section structure corresponding to the evaporation section of the container 10.

[0026] A wick structure (not shown in Figure 1) that generates capillary force is provided in the cavity 13 of the container 10. The wick structure is provided, for example, throughout the entire container 10. Due to the capillary force of the wick structure, the working fluid that has undergone a phase change from the gas phase to the liquid phase in the condensation section of the container 10 is recirculated from the condensation section to the evaporation section of the container 10.

[0027] As shown in Figures 2 and 3, the inner surface 20 of the convex portion 16, which is the evaporation section of the container 10, is provided with a sintered body layer 30, which is made of sintered raw material particles containing metal, as a wick structure. The sintered body layer 30, which is the wick structure, forms the evaporation section structure 1. In the evaporation section structure 1, the sintered body layer 30 forming the evaporation section structure 1 is provided on the tip of the convex portion 16 to which the heating element 200 is thermally connected, i.e., the bottom surface 21 of the convex portion 16, of the inner surface 20 of the convex portion 16. The surface of the sintered body layer 30 is exposed to the internal space of the container 10. In the evaporation section structure 1, the bottom surface 21 of the convex portion 16 is a flat surface. On the other hand, the sintered body layer 30 forming the evaporation section structure 1 is not provided on the side surface 22 of the inner surface 20 of the convex portion 16.

[0028] Furthermore, the sintered body layer 30 is provided only in the evaporation section of the container 10, and is not provided in other parts of the container 10, such as the condensation section. In parts of the container 10 other than the evaporation section, a wick structure with a different structure from the sintered body layer 30 may be provided as needed.

[0029] As shown in Figure 4, the sintered body layer 30 forming the evaporation section structure 1 has an average thickness n and consists of a first portion 31 which is an n / 2 region on the inner surface side of the bottom portion 21 of the container 10, and a second portion 32 which is an n / 2 region on the side of the internal space (cavity portion 13) of the container 10. From the above, the sintered body layer 30 has, in its thickness direction, the first portion 31 on the inner surface side of the container 10 and the second portion 32 on the side of the cavity portion 13 which is the internal space of the container 10. The surface of the second portion 32 is exposed to the cavity portion 13.

[0030] The particle size of the raw material particles containing metal, which are the raw materials for the sintered body layer 30, is not particularly limited. For example, the raw material particles containing metal, which are the raw materials for the sintered body layer 30, are a mixture having first raw material particles having a predetermined average primary particle diameter and second raw material particles having a smaller average primary particle diameter than the first raw material particles. Therefore, the sintered body layer 30 has a first raw material particle sintered section 33 formed by sintering the first raw material particles and a second raw material particle sintered section 34 formed by sintering the second raw material particles. The heat H from the heating element 200, which is thermally connected to the container 10, is transferred to the sintered body layer 30 forming the evaporation section structure 1 via the container 10.

[0031] As shown in Figure 4, the sintered body layer 30 has a plurality of voids 35 inside. In the sintered body layer 30, the porosity of the first portion 31 is smaller than that of the second portion 32. In the sintered body layer 30, the voids 35 of the first portion 31 are more numerous and / or larger than the voids 35 of the second portion 32. In the evaporation section structure 1, a mixture having first raw material particles having a predetermined average primary particle diameter and second raw material particles having a smaller average primary particle diameter than the first raw material particles is used as raw material particles, and the raw material particles are sintered to form a first raw material particle sintered portion 33 and a second raw material particle sintered portion 34, thereby obtaining a sintered body layer 30 in which the porosity of the first portion 31 is smaller than that of the second portion 32. Since raw material particles with a small average primary particle diameter have strong cohesive forces, when the raw material particles, which are a mixture of first and second raw material particles, are sintered, it is thought that in the first region 31, which is the region on the inner surface side of the container 10, the second raw material particles mainly aggregate and form a bulk sintered body. Furthermore, when the raw material particles, which are a mixture of first and second raw material particles, are sintered, it is thought that in the second region 32, which is the region on the cavity side 13, the second raw material particles mainly aggregate between the first raw material particles, resulting in a sintered body in which numerous and / or enlarged voids 35 are formed.

[0032] The sintered body layer 30 of the above structure forming the evaporation section structure 1 can provide the heat transport member 100 with an evaporation section structure that is excellent in the evaporation characteristics of the liquid-phase working fluid sealed in the container 10. The reason why the evaporation section structure 1 of the heat transport member 100 is excellent in the evaporation characteristics of the liquid-phase working fluid is that the first portion 31 of the sintered body layer 30, which is the region on the inner surface side of the container 10, is a sintered body mainly composed of aggregated second raw material particles forming a bulk, thus having excellent heat transfer properties, while the second portion 32, which is the region on the cavity side, which is the internal space of the container 10, is a sintered body with many and / or large voids 35 formed compared to the first portion 31, thus acting as a starting point for the evaporation of the liquid-phase working fluid, that is, the second portion 32 has an evaporation-promoting structure. Furthermore, the evaporation section structure 1 of the heat transport member 100 has a first section 31 and a second section 32 of the above structure, which reduces the thermal resistance between the container 10 and the sintered body layer 30, resulting in an evaporation section structure with excellent evaporation characteristics.

[0033] Furthermore, the sintered body layer 30 of the above structure has a first raw material particle sintered portion 33 derived from raw material particles with a relatively large particle size, which suppresses heat transfer loss at the interface of the sintered portion and thus enables excellent heat transfer performance.

[0034] For example, the sintering conditions for forming the sintered body layer 30 by sintering metal-containing raw material particles include a heating temperature of 500°C to 1000°C and a heating time of 60 minutes to 180 minutes.

[0035] The average primary particle diameter of the first raw material particles is not particularly limited, but its lower limit is preferably 50 μm, and particularly preferably 70 μm, in order to ensure that the porosity of the second portion 32 is reliably larger than that of the first portion 31, thereby reliably obtaining an evaporation-promoting structure in the second portion 32, while reliably obtaining excellent heat transfer performance in the first portion 31. On the other hand, the upper limit of the average primary particle diameter of the first raw material particles is preferably 300 μm, and particularly preferably 200 μm, in order to ensure that the evaporation-promoting structure of the second portion 32 is reliably obtained, while improving the capillary force of the sintered body layer 30.

[0036] The average primary particle diameter of the second raw material particles is not particularly limited as long as it is smaller than the average primary particle diameter of the first raw material particles. However, the lower limit is preferably 1.0 nm, more preferably 10 nm, and particularly preferably 20 nm, in order to impart appropriate cohesive force to the second raw material particles and ensure that the evaporation-promoting structure of the second portion 32 is obtained. On the other hand, the upper limit of the average primary particle diameter of the second raw material particles is preferably 10 μm, more preferably 3.0 μm, even more preferably 1000 nm, and particularly preferably 500 nm, in order to prevent the generation of large voids between the sintered portions 33 of the first raw material particles and improve the capillary force and heat transfer properties of the sintered body layer 30.

[0037] The ratio of the average primary particle diameter of the first raw material particles to the average primary particle diameter of the second raw material particles is not particularly limited as long as it is greater than 1.0, but is preferably 20 to 50,000, and particularly preferably 30 to 10,000, in order to reliably obtain excellent heat transfer in the first part 31, which is the inner surface region of the container 10, and to reliably obtain an evaporation-promoting structure in the second part 32, which is the region on the cavity 13 side, thereby reliably improving the evaporation characteristics of the liquid phase working fluid.

[0038] The mixing ratio of the first raw material particles and the second raw material particles is not particularly limited, but for example, in order to ensure excellent heat transfer in the first part 31, which is the inner surface region of the container 10, and to ensure an evaporation-promoting structure in the second part 32, which is the cavity 13 side, thereby ensuring an improvement in the evaporation characteristics of the liquid phase working fluid, it is preferable to include 10 to 1000 parts by mass of the second raw material particles, and particularly preferable to include 20 to 500 parts by mass of the second raw material particles, per 100 parts by mass of the first raw material particles.

[0039] The average size of the voids 35 in the second portion 32 is preferably 1 μm to 200 μm, and particularly preferably 10 μm to 100 μm, in order to obtain an even better evaporation-promoting structure. The average size of the voids 35 in the second portion 32 can be adjusted by appropriately selecting the average primary particle diameter of the first raw material particles and the average primary particle diameter of the second raw material particles. Furthermore, the average size of the voids 35 in the first portion 31 is preferably 0.5 nm to 5 μm, and particularly preferably 5 nm to 1 μm, in order to obtain even better heat transfer properties. The average size of the voids 35 in the first portion 31 can be adjusted by appropriately selecting the average primary particle diameter of the first raw material particles and the average primary particle diameter of the second raw material particles.

[0040] The average thickness n of the sintered body layer 30 can be appropriately selected depending on the operating conditions of the heat transport member 100. When the heat transport member 100 is a vapor chamber, a thickness of 100 μm to 1.0 mm is preferred, as it ensures that the liquid phase working fluid is reliably returned to the evaporation section while a vapor flow path for the gas phase working fluid is reliably secured.

[0041] Examples of the first raw material particles include metal powders such as copper powder, copper alloy powder, and stainless steel powder. Similarly, examples of the second raw material particles include metal powders such as copper powder, copper alloy powder, and stainless steel powder. The first and second raw material particles may be powders of the same material type or powders of different material types.

[0042] The material of container 10 is not particularly limited, and examples include copper and copper alloys due to their excellent thermal conductivity, aluminum and aluminum alloys due to their light weight, and stainless steel due to its improved mechanical strength. The working fluid sealed in container 10 can be appropriately selected depending on the material of container 10, and examples include water, alternative fluorocarbons, perfluorocarbons, and cyclopentane.

[0043] Examples of wick structures with a different structure from the sintered body layer 30, provided in parts of the container 10 other than the evaporation section, include sintered bodies of raw material particles having an average primary particle diameter different from that of the raw material particles of the sintered body layer 30, and sintered bodies in which the raw material particles consist of first raw material particles.

[0044] Next, the mechanism of the cooling function of the heat sink 120 using a heat transport member 100 equipped with an evaporation section structure 1 will be explained. First, the heat-generating element 200, which is the object to be cooled, is thermally connected to the tip of the protrusion 16 of the container 10. When the container 10 receives heat from the heat-generating element 200 at the protrusion 16, heat is transferred from the heat-generating element 200 to the liquid-phase working fluid accumulated in the sintered body layer 30 of the evaporation section structure 1 at the protrusion 16 of the container 10, and the liquid-phase working fluid undergoes a phase change to a gaseous working fluid. The gaseous working fluid flows through the vapor passage of the cavity 13 from the protrusion 16 to the flat section 17 of the container 10, and diffuses throughout the entire flat section 17. As the gaseous working fluid diffuses from the protrusion 16 to the entire flat section 17 of the container 10, the container 10 transports heat from the heat-generating element 200 from the protrusion 16 to the entire container 10, and the heat from the heat-generating element 200 diffuses throughout the entire container 10. The gaseous working fluid, which can circulate throughout the container 10, undergoes a phase change from gas to liquid by releasing latent heat through the heat exchange action of the heat dissipation fins 110. The released latent heat is transferred to the heat dissipation fins 110, which are thermally connected to the container 10. The heat transferred from the container 10 to the heat dissipation fins 110 is released to the external environment of the heat sink 120 via the heat dissipation fins 110. The working fluid, which has undergone a phase change from gas to liquid by releasing latent heat, recirculates from the flat portion 17 to the convex portion 16 of the container 10 due to the capillary force of the wick structure provided on the container 10.

[0045] Furthermore, the heatsink 120 may be forcibly air-cooled by a blower fan (not shown) if necessary. The cooling air from the blower fan is supplied along the main surface of the heat dissipation fins 110, thereby cooling the heat dissipation fins 110.

[0046] Next, the evaporation section structure in the heat transport member according to the second embodiment of the present invention will be described in detail. Since the evaporation section structure according to the second embodiment shares major components with the evaporation section structure according to the first embodiment, the same reference numerals will be used to describe the same components as those in the evaporation section structure according to the first embodiment. Figure 5 is a perspective view illustrating the outline of the evaporation section structure according to the second embodiment of the present invention. Figure 6 is a cross-sectional view taken along line A-A' in Figure 5.

[0047] In the evaporation section structure 1 according to the first embodiment, a sintered body layer 30 is provided on the bottom surface 21 of the protrusion 16 to which the heating element 200 is thermally connected, while the sintered body layer 30 is not provided on the side surface 22 of the protrusion 16. Instead, as shown in Figures 5 and 6, in the evaporation section structure 2 according to the second embodiment, the sintered body layer 30 forming the evaporation section structure 2 is provided not only on the bottom surface 21 of the inner surface 20 of the protrusion 16 but also on the side surface 22 of the protrusion 16. Therefore, in the evaporation section structure 2, the sintered body layer 30 is provided over substantially the entire inner surface 20 of the protrusion 16.

[0048] In the evaporation section structure 2, a sintered body layer 30 forming the evaporation section structure 2 is also provided on the side portion 22, which improves the evaporation characteristics of the liquid-phase working fluid sealed in the container 10 over substantially the entire surface of the inner surface 20 of the protrusion 16. As a result, an evaporation section structure with even better evaporation characteristics for the liquid-phase working fluid can be achieved.

[0049] Next, the evaporation section structure in the heat transport member according to the third embodiment of the present invention will be described in detail. Since the evaporation section structure according to the third embodiment shares major components with the evaporation section structures according to the first and second embodiments, the same reference numerals will be used to describe the same components as those in the evaporation section structures according to the first and second embodiments. Figure 7 is a perspective view illustrating the outline of the evaporation section structure according to the third embodiment of the present invention. Figure 8 is a cross-sectional view taken along line A-A' in Figure 7.

[0050] As shown in Figures 7 and 8, in the evaporation section structure 3 according to the third embodiment, a plurality of columnar fins 41, 41, 41... are erected on the bottom surface 21 of the inner surface 20 of the protrusion 16. The columnar fins 41 are pin fins. The columnar fins 41 form a container inner surface area increasing section 40 that increases the surface area of ​​the evaporation section on the inner surface of the container 10. The plurality of columnar fins 41, 41, 41... are arranged in parallel on the bottom surface 21 at predetermined intervals. The shape of the columnar fins 41 is not particularly limited, but in the evaporation section structure 3, they are cylindrical. The container inner surface area increasing section 40 formed by the plurality of columnar fins 41, 41, 41... increases the evaporation surface area of ​​the liquid phase working fluid, and facilitates heat transfer from the heat-generating element 200 to the liquid phase working fluid via the container 10. As a result, the phase change of the liquid phase working fluid to the gas phase is promoted. One method for forming the columnar fins 41 is to attach separately manufactured columnar fins 41 to the bottom surface 21 by soldering, brazing, sintering, or the like.

[0051] In the evaporation section structure 3, a sintered body layer 30 forming the evaporation section structure 3 is provided on the bottom surface 21 of the inner surface 20 of the protrusion 16. In addition, in the evaporation section structure 3, the sintered body layer 30 is not provided on the outer surface of the columnar fin 41 or on the side surface 22 of the protrusion 16.

[0052] Even in the evaporation section structure 3, in which the container 10 has an internal surface area increasing section 40, the sintered body layer 30 makes it possible to create an evaporation section structure with excellent evaporation characteristics for the liquid-phase working fluid sealed in the container 10. Furthermore, in the evaporation section structure 3, the internal surface area increasing section 40 consisting of a plurality of columnar fins 41, 41, 41... increases the evaporation surface area of ​​the liquid-phase working fluid, further reducing the thermal resistance when the liquid-phase working fluid undergoes phase change to the gas phase.

[0053] Next, the evaporation section structure in the heat transport member according to the fourth embodiment of the present invention will be described in detail. Since the evaporation section structure according to the fourth embodiment shares major components with the evaporation section structures according to the first to third embodiments, the same reference numerals will be used to describe the same components as those in the evaporation section structures according to the first to third embodiments. Figure 9 is a perspective view illustrating the outline of the evaporation section structure according to the fourth embodiment of the present invention. Figure 10 is a cross-sectional view taken along line A-A' in Figure 9.

[0054] In the evaporation section structure 3 according to the third embodiment, a sintered body layer 30 is provided on the bottom surface 21 of the protrusion 16 to which the heating element 200 is thermally connected, while the outer surface of the columnar fin 41 and the side surface 22 of the protrusion 16 are not provided with a sintered body layer 30. However, as shown in Figures 9 and 10, in the evaporation section structure 4 according to the fourth embodiment, the protrusion 16, which is the evaporation section of the container 10, is provided with a sintered body layer 30 that forms the evaporation section structure 4 not only on the bottom surface 21 of the inner surface 20 of the protrusion 16 but also on the side surface 22. Furthermore, in the evaporation section structure 4, the outer surface of the columnar fin 41 is also provided with a sintered body layer 30 that forms the evaporation section structure 4. Therefore, the columnar fin 41 is covered with a sintered body layer 30.

[0055] In the evaporation section structure 4, a sintered body layer 30 forming the evaporation section structure 4 is also provided on the side portion 22, thereby improving the evaporation characteristics of the liquid-phase working fluid sealed in the container 10 over substantially the entire surface of the inner surface 20 of the protrusion 16, thus enabling an evaporation section structure with further improved evaporation characteristics of the liquid-phase working fluid. Furthermore, in the evaporation section structure 4, a sintered body layer 30 forming the evaporation section structure 4 is also provided on the outer surface of the columnar fin 41, so that the liquid-phase working fluid remains in the increased inner surface area portion 40 of the container due to the capillary force of the sintered body layer 30, thereby preventing the liquid-phase working fluid from drying out in the evaporation section.

[0056] Next, the evaporation section structure in the heat transport member according to the fifth embodiment of the present invention will be described in detail. Since the evaporation section structure according to the fifth embodiment shares major components with the evaporation section structures according to the first to fourth embodiments, the same reference numerals will be used to describe the same components as those in the evaporation section structures according to the first to fourth embodiments. Figure 11 is a perspective view illustrating the outline of the evaporation section structure according to the fifth embodiment of the present invention. Figure 12 is a cross-sectional view taken along line A-A' in Figure 11.

[0057] In the evaporation section structure 3 according to the third embodiment, a plurality of columnar fins 41, 41, 41... are erected on the bottom surface 21 of the inner surface 20 of the protrusion 16 as a container inner surface area increasing section 40. However, as shown in Figures 11 and 12, in the evaporation section structure 5 according to the fifth embodiment, a plurality of plate-shaped fins 42, 42, 42... are erected as a container inner surface area increasing section 40. The plurality of plate-shaped fins 42, 42, 42... are arranged in parallel at predetermined intervals on the bottom surface 21 of the inner surface 20 of the protrusion 16. The shape of the plate-shaped fins 42 is not particularly limited, and in the evaporation section structure 5, they are rectangular in shape when viewed from the front and are thin plates with a rectangular shape when viewed from the side. The container's inner surface area increase section 40, formed by multiple plate-shaped fins 42, 42, 42..., increases the evaporation surface area of ​​the liquid-phase working fluid, thereby facilitating heat transfer from the heat-generating element 200 to the liquid-phase working fluid via the container 10. As a result, the phase change of the liquid-phase working fluid to the gas phase is promoted. As a method for forming the plate-shaped fins 42, for example, a plate-shaped fin 42 that has been separately manufactured can be attached to the bottom surface 21 by soldering, brazing, sintering, or the like.

[0058] In the evaporation section structure 5, a sintered body layer 30 forming the evaporation section structure 5 is provided on the bottom surface 21 of the inner surface 20 of the protrusion 16. In addition, in the evaporation section structure 5, the sintered body layer 30 is not provided on the outer surface of the plate-shaped fin 42 or on the side surface 22 of the protrusion 16.

[0059] Even in the evaporation section structure 5, in which the container inner surface area increasing section 40 is provided in the evaporation section of the container 10, the sintered body layer 30 makes it possible to create an evaporation section structure with excellent evaporation characteristics for the liquid-phase working fluid sealed in the container 10. Furthermore, in the evaporation section structure 5, the container inner surface area increasing section 40 consisting of a plurality of plate-shaped fins 42, 42, 42... increases the evaporation surface area of ​​the liquid-phase working fluid, further reducing the thermal resistance when the liquid-phase working fluid undergoes phase change to the gas phase.

[0060] Next, the evaporation section structure in the heat transport member according to the sixth embodiment of the present invention will be described in detail. Since the evaporation section structure according to the sixth embodiment shares major components with the evaporation section structures according to the first to fifth embodiments, the same reference numerals will be used to describe the same components as those in the evaporation section structures according to the first to fifth embodiments. Figure 13 is a perspective view illustrating the outline of the evaporation section structure according to the sixth embodiment of the present invention. Figure 14 is a cross-sectional view taken along line A-A' in Figure 13.

[0061] In the evaporation section structure 5 according to the fifth embodiment, a sintered body layer 30 is provided on the bottom surface 21 of the protrusion 16 to which the heating element 200 is thermally connected, while the outer surface of the plate-shaped fin 42 and the side surface 22 of the protrusion 16 are not provided with a sintered body layer 30. However, as shown in Figures 13 and 14, in the evaporation section structure 6 according to the sixth embodiment, the protrusion 16, which is the evaporation section of the container 10, is provided with a sintered body layer 30 that forms the evaporation section structure 6 not only on the bottom surface 21 of the inner surface 20 of the protrusion 16 but also on the side surface 22. Furthermore, in the evaporation section structure 6, the outer surface of the plate-shaped fin 42 is not provided with a sintered body layer 30 that forms the evaporation section structure 6.

[0062] In the evaporation section structure 6, a sintered body layer 30 forming the evaporation section structure 6 is also provided on the side portion 22, thereby improving the evaporation characteristics of the liquid-phase working fluid sealed in the container 10 over substantially the entire surface of the inner surface 20 of the protrusion 16, thus enabling an evaporation section structure with further improved evaporation characteristics of the liquid-phase working fluid. Furthermore, in the evaporation section structure 6, a container inner surface area increasing portion 40 consisting of a plurality of plate-shaped fins 42, 42, 42... is provided, increasing the evaporation surface area of ​​the liquid-phase working fluid and further reducing the thermal resistance when the liquid-phase working fluid undergoes phase change to the gas phase.

[0063] Next, other embodiments of the evaporation section structure of the present invention will be described. In the evaporation section structures according to the above embodiments, a protrusion 16 is provided on the container 10, and a sintered body layer 30 is provided on the protrusion 16, which is the evaporation section. However, instead, a container 10 without a protrusion 16 may be used, for example, a flat container 10. In the case of a container 10 without a protrusion 16, the sintered body layer 30 is provided on the part of the container 10 to which the heat-generating element to be cooled is thermally connected, thereby forming the evaporation section structure.

[0064] Furthermore, in embodiments where the sintered body layer 30 forming the evaporation section structure is not provided on the side portion 22 of the protrusion 16 or the container inner surface area increase portion 40, a wick structure having a different structure from the sintered body layer 30 may be provided as needed. Examples of wick structures having a different structure from the sintered body layer 30 include a sintered body of raw material particles having an average primary particle diameter different from that of the raw material particles of the sintered body layer 30, and a sintered body whose raw material particles consist of first raw material particles. In addition, in the evaporation section structure according to the fourth embodiment, the sintered body layer 30 forming the evaporation section structure was provided on the entire outer surface of the container inner surface area increase portion 40, but instead, the sintered body layer 30 may be provided on a part of the outer surface of the container inner surface area increase portion 40.

[0065] In the evaporation chamber structures according to the above embodiments, a vapor chamber equipped with a thin plate-shaped container was used as the heat transport member. However, the heat transport member is not particularly limited as long as it is equipped with a container having an internal space in which a working fluid is sealed and subjected to reduced pressure. For example, a heat pipe in which the container is tubular in shape may also be used. [Industrial applicability]

[0066] The evaporation section structure of the present invention exhibits excellent evaporation characteristics for the liquid-phase working fluid sealed in the container, making it highly valuable for applications such as cooling high-heat-generating heat-generating elements installed in confined spaces. [Explanation of Symbols]

[0067] 1, 2, 3, 4, 5, 6 Evaporation section structure 10 containers 13 Cavity 30 Sintered body layer 31. First part 32. Second part 100 Heat transport member

Claims

1. A heat transport member comprising a container having an internal space containing a working fluid, an evaporation section in which the liquid-phase working fluid undergoes a phase change from liquid to gaseous phase, and a condensation section located separately from the evaporation section in which the gaseous working fluid undergoes a phase change from gaseous to liquid phase, is the evaporation section structure of a heat transport member. A sintered body layer, in which raw material particles containing metal are sintered, is provided on the inner surface of the evaporation section of the container. The sintered body layer, having an average thickness n, consists of a first region which is n / 2 of the inner surface area of ​​the container and a second region which is n / 2 of the inner space area, wherein the porosity of the first region is smaller than the porosity of the second region. The raw material particles are a mixture comprising first raw material particles having a predetermined average primary particle diameter and second raw material particles having a smaller average primary particle diameter than the first raw material particles. The sintered body layer, which consists of a mixture having the first raw material particles and the second raw material particles, is provided only in the evaporation section of the container. The container has a flat portion and a convex portion that protrudes outward from the flat portion and becomes the evaporation portion. The aforementioned flat portion is provided with a heat exchange means, thus forming an evaporation section structure.

2. The evaporation section structure according to claim 1, wherein the sintered body layer is provided on both the bottom surface and the side surface of the inner surface of the protrusion.

3. The evaporation section structure according to claim 1, wherein the sintered body layer is provided on both the bottom and side surfaces of the inner surface of the protrusion, and a plurality of columnar fins are erected on the bottom surface.

4. The evaporation section structure according to claim 1, wherein a plurality of columnar fins are erected on the bottom surface of the inner surface of the protrusion.

5. The evaporation section structure according to claim 1, wherein the container is not provided with a sintered body layer in which raw material particles containing metal are sintered, other than the evaporation section.

6. The evaporation section structure according to claim 1, wherein the average primary particle diameter of the first raw material particles is 50 μm or more and 300 μm or less, and the average primary particle diameter of the second raw material particles is 1.0 nm or more and 10 μm or less.

7. The evaporation section structure according to claim 1 or 6, wherein the average primary particle diameter of the second raw material particles is 1.0 nm or more and 1000 nm or less.

8. The evaporation section structure according to claim 1 or 6, wherein the ratio of the average primary particle diameter of the first raw material particles to the average primary particle diameter of the second raw material particles is 20 or more and 50,000 or less.

9. The evaporation section structure according to claim 1 or 6, wherein the raw material particles contain 10 to 1000 parts by mass of the second raw material particles with respect to 100 parts by mass of the first raw material particles.

10. The evaporation section structure according to claim 1 or 6, wherein the first raw material particles include copper and / or copper alloy particles, and the second raw material particles include copper and / or copper alloy particles.

11. The evaporation section structure according to any one of claims 1 to 6, wherein the average size of the voids in the second section is 1 μm or more and 200 μm or less.

12. The evaporation section structure according to any one of claims 1 to 6, wherein the average thickness n of the sintered body layer is 100 μm or more and 1.0 mm or less.

13. A heat transport member having the evaporation section structure described in any one of claims 1 to 6.

14. The heat transport member according to claim 13, which is a vapor chamber.

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