CN112363593B

CN112363593B - Heat conduction structure, manufacturing method thereof and mobile device

Info

Publication number: CN112363593B
Application number: CN202010586702.8A
Authority: CN
Inventors: 萧毅豪; 何铭祥
Original assignee: Henan Sili New Material Technology Co ltd
Current assignee: Henan Sili New Material Technology Co ltd
Priority date: 2019-06-28
Filing date: 2020-06-24
Publication date: 2023-06-02
Anticipated expiration: 2040-06-24
Also published as: TWI692606B; TW202100934A; CN112363593A

Abstract

The invention provides a heat conduction structure, a manufacturing method thereof and a mobile device. The invention discloses a heat conduction structure, which comprises a heat conduction unit, a first heat conduction layer, a metal microstructure, a second heat conduction layer, a fourth heat conduction layer and a working fluid. The closed cavity of the heat conduction unit is provided with a bottom surface and a top surface which are opposite, and the first heat conduction layer is arranged on the bottom surface and/or the top surface of the closed cavity. The metal microstructure is disposed on the first heat conduction layer, so that the first heat conduction layer is located between the metal microstructure and the bottom surface and/or the top surface. The second heat conduction layer is arranged on one side of the metal microstructure far away from the first heat conduction layer. The fourth heat conducting layer is arranged in the inner side surface of the closed cavity and is not provided with the first heat conducting layer, the metal microstructure and the second heat conducting layer. The working fluid is arranged in the closed cavity of the heat conducting unit. The invention also discloses a manufacturing method of the heat conduction structure and a mobile device.

Description

Heat conduction structure, manufacturing method thereof and mobile device

Technical Field

The invention discloses a heat conduction structure, a manufacturing method thereof and a mobile device with the heat conduction structure.

Background

With the development of technology, no priority is given to the design and development of mobile devices, such as thinning and high performance. In the case of high-speed operation and thin-profile, the computing chip (such as a cpu) inside the mobile device must provide high-efficiency execution speed, and of course, generate relatively high heat (temperature even exceeding 100 ℃), which may cause permanent damage to the components or the mobile device if the heat is not directed to the outside.

In order to avoid overheating of the device, a heat dissipation structure is generally installed in the prior art to dissipate heat generated by the mobile device by conduction, convection, radiation, and the like. In addition, as the design of the mobile device is thinner and thinner, the space for arranging various electronic components therein is also narrowed, and the embedded heat dissipation structure must conform to the design of the narrow space.

Therefore, how to develop a heat conduction structure more suitable for the requirements of high-power devices or devices, which can be suitable for the heat dissipation requirements of light and thin mobile devices, has been one of the continuous pursuits of related manufacturers.

Disclosure of Invention

The invention aims to provide a heat conduction structure, a manufacturing method thereof and a mobile device. The heat conduction structure of the invention has higher heat conduction efficiency, can rapidly conduct out the heat energy generated by a heat source, and can be suitable for the heat dissipation requirement of the light and thin mobile device.

To achieve the above object, a heat conduction structure according to the present invention includes a heat conduction unit, a first heat conduction layer, a metal microstructure, a second heat conduction layer, a fourth heat conduction layer, and a working fluid. The heat conduction unit forms a closed cavity, and the closed cavity is provided with a bottom surface and a top surface which are opposite. The metal microstructure is disposed on the first heat conduction layer, so that the first heat conduction layer is located between the metal microstructure and the bottom surface and/or the top surface. The second heat conduction layer is arranged on one side of the metal microstructure far away from the first heat conduction layer. The fourth heat conducting layer is arranged in the inner side surface of the closed cavity and is not provided with the first heat conducting layer, the metal microstructure and the second heat conducting layer. The working fluid is arranged in the closed cavity of the heat conducting unit.

In one embodiment, the first thermally conductive layer or the second thermally conductive layer overlies at least a portion of the surface of the metal microstructure.

In one embodiment, the first heat conductive layer, the metal microstructure and the second heat conductive layer form a stacked structure, and the stacked structure is divided into at least two sections along the long axis direction of the heat conductive unit, wherein the at least two sections comprise a first section and a second section, and the materials of the first heat conductive layer and the second heat conductive layer in the first section are at least partially different from those of the first heat conductive layer and the second heat conductive layer in the second section.

In one embodiment, the metallic microstructure is in the form of a metallic mesh, a metallic powder, or metallic particles, or a combination thereof.

In one embodiment, the material of the first thermally conductive layer or the second thermally conductive layer comprises graphene, graphite, carbon nanotubes, aluminum oxide, zinc oxide, titanium oxide, or boron nitride, or a combination thereof.

In one embodiment, the thermally conductive structure further comprises a third thermally conductive layer disposed on a side of the second thermally conductive layer remote from the metal microstructure.

In one embodiment, the first heat conducting layer, the metal microstructure, the second heat conducting layer and the third heat conducting layer form a stacked structure, and the stacked structure is divided into at least two sections along the long axis direction of the heat conducting unit, wherein the at least two sections comprise a first section and a second section, and the materials of the first heat conducting layer, the second heat conducting layer and the third heat conducting layer in the first section are at least partially different from those of the first heat conducting layer, the second heat conducting layer and the third heat conducting layer in the second section.

In one embodiment, the third thermally conductive layer comprises a plurality of nanotubes with an axial direction perpendicular to the surface of the second thermally conductive layer.

In one embodiment, the fourth thermally conductive layer covers in the interior surface of the closed cavity, without the coverage of the first thermally conductive layer, the metal microstructure, and the second thermally conductive layer being greater than or equal to 0.01% and less than or equal to 100%.

In one embodiment, the thermally conductive structure further comprises a carbon material added to the working fluid.

In order to achieve the above object, a mobile device according to the present invention includes a heat source and the aforementioned heat conducting structure, and one end of the heat conducting structure contacts the heat source.

To achieve the above object, a method for manufacturing a heat conductive structure according to the present invention includes: forming a first heat conductive layer on the first substrate and/or the second substrate; forming a metal microstructure on the first substrate and/or the second substrate, so that the first heat conduction layer is positioned between the metal microstructure and the first substrate and/or the second substrate; forming a second heat conducting layer on the side of the metal microstructure away from the first heat conducting layer; combining the first substrate and the second substrate to form a heat conducting unit, wherein the heat conducting unit forms a closed cavity, wherein prior to the step of combining the first substrate and the second substrate, further comprising forming a fourth heat conducting layer in the inner side surface of the closed cavity at a location not having the first heat conducting layer, the metal microstructure, and the second heat conducting layer; and injecting a working fluid into the closed cavity through the notch of the heat conducting unit.

To achieve the above object, another method of manufacturing a heat conductive structure according to the present invention includes forming a first heat conductive layer on a metal microstructure; forming a second heat conducting layer on the side of the metal microstructure away from the first heat conducting layer; disposing a metal microstructure having a first heat conduction layer and a second heat conduction layer on the first substrate and/or the second substrate, such that the first heat conduction layer is located between the metal microstructure and the first substrate and/or the second substrate; combining the first substrate and the second substrate to form a heat conducting unit, wherein the heat conducting unit forms a closed cavity, wherein prior to the step of combining the first substrate and the second substrate, further comprising forming a fourth heat conducting layer in the inner side surface of the closed cavity at a location not having the first heat conducting layer, the metal microstructure, and the second heat conducting layer; and injecting a working fluid into the closed cavity through the notch of the heat conducting unit.

In one embodiment, before the step of combining the first substrate and the second substrate, the method further comprises the steps of: a third thermally conductive layer is formed on a side of the second thermally conductive layer remote from the metal microstructure.

In one embodiment, before the step of combining the first substrate and the second substrate, the method further comprises the steps of: a fourth heat conductive layer is formed in the inner surface of the closed cavity at a position where the first heat conductive layer, the metal microstructure, the second heat conductive layer, and the third heat conductive layer are not present.

In the heat conduction structure, the manufacturing method thereof and the mobile device, the first heat conduction layer and the second heat conduction layer are arranged on two sides of the metal microstructure in the heat conduction structure, and the fourth heat conduction layer is arranged in the inner side surface of the closed cavity and is not provided with the first heat conduction layer, the metal microstructure and the second heat conduction layer, so that the hydrophilicity of the metal microstructure can be increased, the reflux rate of liquid working fluid in the metal microstructure is increased, the circulation efficiency of the working fluid can be further improved, and the uniform temperature effect and the heat conduction effect of the heat conduction structure are better. Therefore, the heat conduction structure of the invention has higher heat conduction efficiency, can rapidly conduct out the heat energy generated by the heat source, and can be suitable for the heat dissipation requirement of the light and thin mobile device.

In some embodiments, the heat conductive structure of the present invention may further include a third heat conductive layer disposed on a side of the second heat conductive layer away from the metal microstructure, where the third heat conductive layer may increase the coverage and hydrophilicity, and may also increase the protection of the metal microstructure from corrosion or oxidation, in addition to increasing the heat conductive efficiency of the heat conductive structure.

Drawings

Fig. 1A is a schematic view of a heat conduction structure according to an embodiment of the present invention.

FIG. 1B is a schematic cross-sectional view of the thermally conductive structure of FIG. 1A along the line A-A.

FIG. 1C is a schematic cross-sectional view of the heat transfer structure of FIG. 1A along the X-X cut line.

Fig. 1D and 1E are schematic views of different embodiments of the heat conduction structure of fig. 1B, in which a first heat conduction layer and a second heat conduction layer are respectively disposed on two sides of a metal microstructure.

Fig. 1F is a schematic cross-sectional view of a heat transfer structure according to another embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view of a heat transfer structure according to another embodiment of the present invention.

Fig. 3A, 3B and 3C are respectively different cross-sectional views of a heat conduction structure according to another embodiment of the present invention.

Fig. 4 is a schematic diagram of a mobile device according to an embodiment of the invention.

Fig. 5A and 5B are schematic views of different manufacturing processes of the heat conduction structure of the present invention.

Fig. 6A to 6E are schematic views of a manufacturing process of a heat conduction structure according to an embodiment of the invention.

Fig. 7A and 7B are schematic views of a portion of another process for manufacturing a thermally conductive structure according to an embodiment of the present invention.

Detailed Description

The heat conductive structure and the manufacturing method thereof, and the mobile device according to some embodiments of the present invention will be described below with reference to the related drawings, in which like components will be described with like reference numerals. The components presented in the examples below are illustrative only and do not represent true proportions and dimensions.

The heat conduction structure has higher heat conduction efficiency, and can be applicable to the heat dissipation requirement of the light and thin mobile device besides rapidly conducting the heat energy generated by the heat source. The heat conduction structure can be arranged in the mobile device, one end of the heat conduction structure can contact with the heat source, so that heat generated by the heat source can be transmitted to the other end of the heat conduction structure through the guidance of the heat conduction structure, and the mobile device is prevented from being halted or burnt due to the high temperature of the heat source. In some embodiments, the heat source may be, for example, but not limited to, a Central Processing Unit (CPU), memory chip (card), display chip (card), panel, or power component, or other element, unit, or component that generates high temperature heat energy, including a mobile device. In addition, the mobile device may be, for example, but not limited to, a mobile phone, a notebook computer, a tablet computer, a television, or a display related mobile electronic device, or other field mobile devices.

In addition, the heat conduction structure of the present application may be a temperature equalizing plate or a heat pipe (or referred to as a heat conduction pipe). The heat pipe is a round pipe, and the heat conduction mode is a one-dimensional and linear heat conduction mode; the temperature equalizing plate is a two-dimensional and surface heat conduction mode, and is a high-performance heat dissipation device capable of rapidly conducting a local heat source to the other side of the flat plate, so that the heat dissipation problem under more severe conditions can be solved, and the heat dissipation efficiency is higher. The heat conduction structure of the following embodiment is exemplified by a flat plate-like temperature equalizing plate, but is still applicable to a heat pipe. In addition, for illustrating the internal structure of the heat conduction structure, the length and shape shown in the following drawings are only schematic, and in practical application, the heat conduction structure may be bent in a horizontal direction and/or a vertical direction, and the bending manner may be determined according to the heat source of the mobile device to be heat-dissipated and the internal space thereof.

Referring to fig. 1A to 1C, fig. 1A is a schematic diagram of a heat conduction structure according to an embodiment of the invention, fig. 1B is a schematic cross-sectional view of the heat conduction structure of fig. 1A along A-A cut line, and fig. 1C is a schematic cross-sectional view of the heat conduction structure of fig. 1A along X-X cut line. The direction along the X-X cutting line is the long axis direction of the heat conduction structure (or the heat conduction unit).

As shown in fig. 1A to 1C, the heat conductive structure 1 may include a heat conductive unit 11, a first heat conductive layer 12, a metal microstructure 13, at least one second heat conductive layer 14, and a working fluid 15.

The heat conducting unit 11 is enclosed to form a closed cavity 111, and the closed cavity 111 has a bottom surface B and a top surface T opposite to each other. In some embodiments, the heat conduction structure 1 may be a relatively thin plate body, and its thickness may be less than 0.4mm, for example, 0.35mm, so as to be suitable for the heat conduction and heat dissipation requirements of the thin mobile device. The opposite ends of the heat conduction unit 11 serve as a heat source end H (heat source side) and a cooling end C (cooling side), respectively. As shown in fig. 1A and 1C, the heat source end (side) H may be an end (side) of the heat conducting unit 11, which is close to the heat source, and the cooling end (side) C may be an end (side) of the heat conducting unit 11, which is far from the heat source. In addition, the heated portion of the closed cavity 111 of the heat conducting unit 11 may be referred to as an evaporation area, the other side opposite to the evaporation area may be referred to as a condensation area, the working fluid 15 may absorb heat in the evaporation area and evaporate and rapidly expand to the whole closed cavity 111, and emit heat in the condensation area to condense into a liquid state, and then flow back to the evaporation area, so that the heat is transferred quickly and the temperature is equalized.

The heat conducting unit 11 has a structural function of withstanding internal and external pressure differences, and is made of a dielectric material capable of conducting heat in and out. The heat conducting unit 11 may be formed by welding a plurality of metal plates, or may be a single member integrally formed. The present embodiment is exemplified by two recessed metal plates (e.g., the first substrate 10a and the second substrate 10B in fig. 1B) that are correspondingly connected (e.g., soldered). The preferred material for the heat conducting unit 11 is a metal, such as, but not limited to, a high heat conducting metal material including copper, aluminum, iron, silver, gold, etc. This example is given as copper.

The first heat conducting layer 12 is disposed on the bottom surface B and/or the top surface T of the closed cavity 111. The first heat conducting layer 12 of the present embodiment is exemplified as being disposed on the bottom surface B of the closed cavity 111. In some embodiments, the first heat conducting layer 12 may also be disposed on the top surface T of the closed cavity 111; alternatively, the bottom surface B and the top surface T of the closed cavity 111 are each provided with the first heat conductive layer 12.

The metal microstructure 13 is disposed on the first heat conductive layer 12, such that the first heat conductive layer 12 is located between the metal microstructure 13 and the bottom surface B and/or the top surface T. In this embodiment, the metal microstructure 13 is disposed on the bottom surface B with the first heat conductive layer 12, so that the first heat conductive layer 12 can be located between the metal microstructure 13 and the bottom surface B. The metal microstructures 13 may be capillary structures (wick), which may be in the form of metal mesh, metal powder, metal particles (including nano-metal particles), metal pillars (e.g., cylinders, pyramids, or tetragonal pillars), or combinations thereof, or may be a structure of metal material coated with non-metal material, or other forms that increase the contact surface area of the thermally conductive layer, such as but not limited to highly thermally conductive metal materials including copper, aluminum, iron, silver, gold, or combinations thereof, or other suitable materials. The capillary structure (metal microstructure 13) may have different designs, and four types of capillary structures are commonly known, and the capillary structures are respectively: grooved, meshed (woven), fibrous, and sintered. Since the inner side of the heat conducting unit 11 has the metal microstructure 13, the liquid working fluid 15 condensed after the heat of the gaseous working fluid 15 is dissipated to the outside of the heat conducting unit 11 in the condensation area (cooling end C) can flow back (flow direction D2 of fig. 1C) to the evaporation area (heat source end H) along the metal microstructure 13 through the bottom surface B of the heat conducting unit 11, so that the working fluid 15 can continuously circulate back in the heat conducting unit 11. The metal microstructure 13 of the present embodiment is exemplified by a copper mesh.

At least one second heat conducting layer 14 is arranged on the side of the metal microstructure 13 remote from the first heat conducting layer 12. As shown in fig. 1B, a second heat conductive layer 14 is disposed on the metal microstructure 13, such that the metal microstructure 13 is located between the second heat conductive layer 14 and the first heat conductive layer 12 (the reference symbol "S" in fig. 1C represents a stacked structure of the second heat conductive layer 14, the metal microstructure 13 and the first heat conductive layer 12). The first heat conductive layer 12 and the second heat conductive layer 14 may comprise a material with high thermal conductivity, which may be an organic material or an inorganic material, the organic material may comprise a carbon material, such as, but not limited to, graphite, graphene, carbon nanotubes, carbon spheres, carbon wires, etc., and the inorganic material may comprise a high thermal conductivity metal, such as, but not limited to, a high thermal conductivity metal, or a combination thereof.

In some embodiments, the first thermally conductive layer 12 or the second thermally conductive layer 14 overlies a surface of at least a portion of the metallic microstructure 13; in some embodiments, the coverage of the first heat conductive layer 12 or the second heat conductive layer 14 on the surface of the metal microstructure 13 may be 0.001% or more and 100% or less (0.001% or less coverage or 100% or less, 100% meaning that the entire surface is covered). In some embodiments, the coverage of the surface of the metal microstructure 13 by the first heat conduction layer 12 or the second heat conduction layer 14 may be 5% or more and 100% or less (5% or less coverage or 100%), for example, 7%, 10%, 12%, 15%, 20%, 25%, 30%, …, 90%, or the like; in some embodiments, the coverage of the surface of the metal microstructure 13 by the first heat conduction layer 12 or the second heat conduction layer 14 may be 0.001% or more and 5% or less (0.001% or less coverage or 5% or less), for example, 0.005%, 0.01%, 0.02%, 0.5%, 1%, …%, or 3%, etc., without limitation. In addition, the above-mentioned features of the first heat conduction layer 12 or the second heat conduction layer 14 covering at least a portion of the metal microstructure 13 and the coverage rate thereof can also be applied to other embodiments of the present invention.

In some embodiments, the materials of the first and second thermally

conductive layers

12, 14 include, for example, but are not limited to, graphene, graphite, multi-walled carbon nanotubes, aluminum oxide, zinc oxide, titanium oxide, or boron nitride, or combinations thereof, or other highly thermally conductive inorganic materials, or organic materials. The above is provided withThe machine material may include 0D (Dimension), 1D, 2D, or 3D, among others. Wherein the 0D material is, for example, but not limited to, graphene quantum dots; 1D materials such as, but not limited to, carbon nanotubes; the 2D material is for example but not limited to graphene platelets or molybdenum disulfide (MoS ₂ ) The method comprises the steps of carrying out a first treatment on the surface of the And the 3D material is, for example, but not limited to, graphite. The preferred material for the first and second thermally

conductive layers

12 and 14 is graphene, or carbon nanotubes, or a combination thereof. In this embodiment, the first heat conduction layer 12 and the second heat conduction layer 14 are made of the same material and are both graphene. In some embodiments, the first heat conductive layer 12 or the second heat conductive layer 14 may cover a portion or all of the surface of the metal microstructure 13. In some embodiments, the first and second thermally

conductive layers

12, 14 may each be graphene thermally conductive films (Graphene Thermal Film, GTF).

Since the graphene material (the first heat conducting layer 12 and the second heat conducting layer 14) has good xy-plane thermal conductivity, the heat conduction efficiency of the metal microstructure 13 can be increased. In addition, the graphene material (the first heat conduction layer 12 and the second heat conduction layer 14) can also increase the hydrophilicity of the metal microstructure 13 (such as copper mesh), and can protect the metal microstructure 13 from oxidation and corrosion. The better the hydrophilicity, the smaller the contact angle (contact angle), the more easily the working fluid 15, such as water and water vapor, in the closed cavity 111 can be continuously attached to the surface of the graphene, so that the water is easier to evaporate, the water vapor is easier to condense, the circulating reflux speed can be faster, and the heat energy can be conducted more rapidly. It should be noted that the second heat conductive layer 14 is disposed on the side of the metal microstructure 13 away from the first heat conductive layer 12 in this embodiment, and in various embodiments, multiple layers of the second heat conductive layer 14 (e.g. multiple layers of graphene films) may be disposed on the metal microstructure 13. Furthermore, in various embodiments, the materials of the first thermally conductive layer 12 and the second thermally conductive layer 14 may be different.

Referring to fig. 1D and fig. 1E, which are schematic views of different embodiments of the heat conduction structure of fig. 1B, wherein the first heat conduction layer and the second heat conduction layer are respectively disposed on two sides of the metal microstructure.

The metal microstructure 13 of fig. 1D is a copper mesh, and the materials of the first heat conduction layer 12 and the second heat conduction layer 14 are respectively graphene. In fig. 1D, a portion of the metal microstructure 13 (copper mesh) is disposed (connected) on the surface of the first substrate 10a, and a plurality of graphene materials (forming the first heat conductive layer 12) are disposed and cover a portion of the lower surface of the metal microstructure 13 and are located between the metal microstructure 13 and the first substrate 10 a. An additional graphene material (forming the second thermally conductive layer 14) is disposed and covers a portion of the upper surface of the metal microstructures 13 such that the metal microstructures 13 may be interposed between the first thermally conductive layer 12 and the second thermally conductive layer 14.

In addition, the metal microstructure 13 in fig. 1E is made of copper powder, and the materials of the first heat conduction layer 12 and the second heat conduction layer 14 are still graphene. In fig. 1E, a part of the metal microstructure 13 (copper powder) is disposed (connected) on the surface of the first substrate 10a, and a graphene material (forming the first heat conductive layer 12) is disposed and covers a part of the lower surface of the metal microstructure 13 and is located between the metal microstructure 13 and the first substrate 10 a. An additional graphene material (forming the second thermally conductive layer 14) is disposed and covers a portion of the upper surface of the metal microstructures 13 such that the metal microstructures 13 may be interposed between the first thermally conductive layer 12 and the second thermally conductive layer 14.

Referring to fig. 1B and fig. 1C again, the working fluid 15 is filled and disposed in the closed cavity 111 of the heat conducting unit 11. Since the heat source end H of the heat conduction structure 1 contacts with the heat source, heat can be conducted to the heat source end H of the heat conduction unit 11 (the arrow facing the inside of the heat source end H in fig. 1C indicates that heat is transferred into the heat source end H), so that the heat source end H has a higher temperature and the working fluid 15 in the heat source end H can be vaporized into a gaseous state. The working fluid 15 may be a refrigerant, or other heat-conducting fluid, such as, but not limited to, freon (Freon), ammonia, acetone, methanol, ethylene glycol, propylene glycol, dimethyl sulfoxide (Dimethyl sulfoxide, DMSO), water, etc., and may be determined according to the type or style of the heat source of the mobile device, so long as the selected working fluid 15 is vaporized into a gaseous state at the heat source end H by the heat source temperature, and condensed back at the cooling end C. The working fluid 15 of the present embodiment is exemplified by water.

It should be noted that when the refrigerant is selected as the working fluid 15, and before the refrigerant is injected into the heat conducting unit 11, the closed cavity 111 is first vacuumized to prevent impurity gases (such as air) other than the working fluid 15 from existing inside the heat conducting unit 11, which are called non-condensing gases because they do not participate in the vaporization-condensation cycle, and the non-condensing gases occupy a certain volume of space in the cavity of the heat conducting unit 11 during operation of the heat conducting structure 1, which affects the heat conducting efficiency of the heat conducting structure 1. In addition, the heat conduction structure 1 and the heat source are connected, for example, but not limited to, by a heat conduction paste or a heat dissipation paste, and the heat source of the mobile device can be connected with the heat source end H of the heat conduction structure 1 through the heat conduction paste or the heat dissipation paste, so as to conduct the heat energy of the heat source to the heat source end H of the heat conduction structure 1. In some embodiments, the thermal paste or heat dissipating paste may include a hardener of a thermally conductive silicone composition, a thermally conductive filler, a silicone resin, and an organic peroxide compound; in some embodiments, the material of the thermal paste or the heat dissipating paste may also include an acryl-based adhesive material.

Therefore, when the heat conduction structure 1 contacts with the heat source, the heat source end H of the heat conduction unit 11 can have a higher temperature, so that the working fluid 15 at the heat source end H can be vaporized into a gaseous state, and the gaseous working fluid 15 moves along the flow path of the closed cavity 111 toward the cooling end C (i.e. along the flow direction D1), so as to take away the heat generated by the heat source through the working fluid 15; the heat of the working fluid 15 reaching the cooling end C can be dissipated to the outside of the heat conducting unit 11 (the arrow away from the cooling end C indicates that the heat is dissipated from the cooling end C to the outside). Because the metal microstructure 13 is disposed on the bottom surface B of the heat conducting unit 11, the condensed liquid working fluid 15 can flow back to the heat source end H (flow direction D2) along the metal microstructure 13, so that the working fluid 15 can continuously circulate back in the heat conducting unit 11 to continuously take heat of the heat source away and dissipate from the cooling end C.

In the present embodiment, the materials of the first heat conducting layer 12 and the second heat conducting layer 14 are graphene, which are respectively disposed at two sides of the metal microstructure 13, so as to increase the hydrophilicity of the metal microstructure 13 (e.g. copper mesh), thereby increasing the rate at which the gaseous working fluid 15 leaves the metal microstructure 13 and the liquid working fluid 15 enters the metal microstructure 13, so that the liquid working fluid 15 can quickly flow back to the heat source end H via the flow direction D2, thereby accelerating the circulation efficiency of the working fluid 15, and making the heat transfer structure 1 have better temperature uniformity and heat transfer effects. Compared to the conventional temperature uniformity plate structure (without the first heat conduction layer 12 and the second heat conduction layer 14), the heat conduction structure 1 of the present embodiment can further guide the heat energy from the heat source end H to the cooling end C rapidly, so as to reduce the temperature difference between the heat source end H and the cooling end C, wherein the smaller the temperature difference, the less the heat conduction obstruction, and the better the heat conduction efficiency.

In some embodiments, the above-mentioned organic material (such as carbon material, 0D, 1D, 2D, or 3D material), or inorganic material, or other material with high thermal conductivity, or a combination thereof, may be added to the working fluid 15 to increase the heat conduction efficiency of the working fluid 15. In some embodiments, the working fluid 15 may be charged with a carbon material in an amount of 0.0001% or more and 2% or less (0.0001% or more and 2% or less). In some embodiments, the loading may be greater than or equal to 0.0001%, and less than or equal to 1.5% (0.0001% 1.5%), such as 0.00015%, 0.005%, 0.01%, 0.03%, 0.1%, 0.5%, 1%, or 1.25%, etc., or other proportions, without limitation. The above-mentioned addition amounts are only examples, and are not intended to limit the present invention, so long as the addition amount is between 0.0001% and 2%, the heat conduction efficiency of the working fluid can be improved, and the heat conduction efficiency of the heat conduction structure can be further improved. It should be noted that the above feature of adding an organic material (e.g., a carbon material, a 0D, 1D, 2D, or 3D material), or an inorganic material, or other materials with high thermal conductivity to the working fluid 15 can also be applied to other embodiments of the present invention.

Additionally, in some embodiments, the sum of the thicknesses of the first and second heat

conductive layers

12, 14 closer to the heat source end H may be greater than the sum of the thicknesses of the first and second heat

conductive layers

12, 14 farther from the heat source end H. The first heat conductive layer 12, the metal microstructure 13 and the second heat conductive layer 14 may be referred to as a stacked structure S. In some embodiments, the thickness of the stacked structure S may be reduced in a stepwise manner. Specifically, please refer to fig. 1F, which is a schematic cross-sectional view of a heat conduction structure according to another embodiment of the present invention. In the case where the thickness of the metal microstructure 13 is unchanged, the sum of the thicknesses of the first heat conduction layer 12 and the second heat conduction layer 14 in fig. 1F is reduced by stepwise changes in the direction along the X-X cutting line (along the long axis direction of the heat conduction unit 11) so that the sum of the thicknesses of the first heat conduction layer 12 and the second heat conduction layer 14 closest to the heat source end H is maximized and the sum of the thicknesses of the first heat conduction layer 12 and the second heat conduction layer 14 closest to the cooling end C is minimized in the stacked structure S. The "thickness sum" of the present application may be "a thickness sum of one point" or "an average thickness sum of one small area", without limitation.

Here, the above-described stacked structure S may be divided into at least two sections in a direction along the X-X cutting line (i.e., a long axis direction of the heat conductive unit 11), and the at least two sections may include a first section and a second section. Taking fig. 1F as an example, the stacked structure S closest to the heat source end H may be the first section S1, the stacked structure S closest to the cooling end C may be the second section S2 (the sum of the thicknesses of the first section S1 is d1, the sum of the thicknesses of the second section S2 is d3, d1> d 3), and in some embodiments, the sum of the thicknesses of the first heat conduction layer 12, the second heat conduction layer 14 in the first section S1 may be 1 nanometer (nm) or more and 500 micrometers (μm) or less (1 nm. Ltoreq.thickness and 500 μm), for example, 10nm, 500nm, 1 μm, 20 μm, 350 μm, 450 μm, etc., or other values, and the sum of the thicknesses of the first heat conduction layer 12, the second heat conduction layer 14 in the second section S2 may be more than 0 and 1nm (0 < thickness and 1 nm), for example, 0.08nm, 0.1nm, 0.5nm, 0.75nm, 0.9nm, etc., or other values are not limited. In some embodiments, the sum of the thicknesses of the first and second heat

conductive layers

12, 14 in the first section S1 may be 1nm or more and 1 micrometer (μm) or less (1 nm.ltoreq.d1.ltoreq.1μm), such as 1.5nm, 50nm, 100nm, 400nm, 500nm, 850nm, 900nm, etc., or other values, while the sum of the thicknesses of the first and second heat

conductive layers

12, 14 in the second section S2 may be 0 or more and 0.1nm or less (0 < d 3.ltoreq.0.1 nm), such as 0.01nm, 0.03nm, 0.05nm, 0.075nm, 0.08nm, 0.09nm, 0.95nm, etc., or other values, without limitation.

The reason for using the above thickness and its limitations is that: during the cycling of the working fluid 15 at high and low temperatures, prolonged use may damage the adhesion of the first thermally conductive layer 12 and/or the second thermally conductive layer 14 (graphene) material and degrade the material. Therefore, the thicker heat conduction layer (the first heat conduction layer 12 and the second heat conduction layer 14) is arranged at the first section with high temperature, so that the degradation of the (graphene) material and the damage of the adhesiveness thereof can be delayed, and the service life of the heat conduction structure and the reliability of the product can be further improved.

In some embodiments, the thickness of the first thermally conductive layer 12 may be fixed, but the thickness of the second thermally conductive layer 14 is varied; alternatively, the thickness of the second heat conducting layer 14 is fixed, but the thickness of the first heat conducting layer 12 is changed; alternatively, the thicknesses of the first heat conductive layer 12 and the second heat conductive layer 14 may be changed at the same time, so long as the sum of the thicknesses of the first heat conductive layer 12 and the second heat conductive layer 14 closer to the heat source end H may be greater than the sum of the thicknesses of the first heat conductive layer 12 and the second heat conductive layer 14 farther from the heat source end H. In addition, fig. 1F illustrates that the thickness sum of the first heat conductive layer 12 and the second heat conductive layer 14 is changed in a stepwise manner to maximize the thickness sum adjacent to the heat source end H and minimize the thickness sum adjacent to the cooling end C. However, in different embodiments, the thickness sum of the first heat conductive layer 12 and the second heat conductive layer 14 may be changed in an asymptotically manner (from the thickest to the thinnest) without limitation, so long as the thickness sum of the first heat conductive layer 12 and the second heat conductive layer 14 closer to the heat source end H may be greater than the thickness sum of the first heat conductive layer 12 and the second heat conductive layer 14 farther from the heat source end H. Furthermore, in some embodiments, even though two different heat conducting structures have the above-described limitations on the thickness sum, the greater the thickness sum of the first heat conducting layer 12 and the second heat conducting layer 14 of a certain heat conducting structure, the better the temperature equalizing effect and the better the protection of the material. The better the temperature equalizing effect, the smaller the temperature difference between the heat source end H and the cooling end C, the more rapidly the heat energy can be guided from the heat source end H to the cooling end C. It is noted that the features of the thickness and limitations described above may also be applied to other embodiments of the present invention.

In addition, taking fig. 1F as an example, the area of the sum d1 of the thicknesses of the first heat conductive layer 12 and the second heat conductive layer 14 closest to the heat source end H is a first section S1, and the area of the sum d3 of the thicknesses of the first heat conductive layer 12 and the second heat conductive layer 14 closest to the cooling end C is a second section S2 (d 1> d 3), wherein the materials of the first heat conductive layer 12 and the second heat conductive layer 14 in the first section S1 are at least partially different from the materials of the first heat conductive layer 12 and the second heat conductive layer 14 in the second section S2. For example, in the stepped stacked structure S of fig. 1F, the materials of the first heat conduction layer 12 and the second heat conduction layer 14 in the first section S1 are, for example, graphene and graphene, respectively, but the materials of the first heat conduction layer 12 and the second heat conduction layer 14 in the second section S2 are, for example, graphene and carbon nanotubes, respectively, so long as the materials of any one layer of the first heat conduction layer 12 and the second heat conduction layer 14 in any two sections of the stacked structure S are different, i.e., at least partially different conditions are satisfied for the materials of the first heat conduction layer 12 and the second heat conduction layer 14 in at least two sections. In addition, the first heat conductive layer 12 and the second heat conductive layer 14 in at least two sections of the stacked structure have different material characteristics, and can be applied to other embodiments of the present invention.

In addition, please refer to fig. 2, which is a schematic cross-sectional view of a heat conduction structure according to another embodiment of the present invention.

The heat conducting structure 1a of fig. 2 is substantially identical to the heat conducting structure 1 of fig. 1B. The main difference from the heat conduction structure 1 is that the heat conduction structure 1a of the present embodiment may further include a third heat conduction layer 16, where the third heat conduction layer 16 is disposed on a side of the second heat conduction layer 14 away from the metal microstructure 13. Here, the third heat conductive layer 16 is disposed on the second heat conductive layer 14 such that the third heat conductive layer 16, the second heat conductive layer 14, the metal microstructure 13, and the first heat conductive layer 12 are sequentially stacked on the bottom surface B of the heat conductive unit 11. The third thermally conductive layer 16 may be an organic or inorganic material as described above. In some embodiments, the material of the third thermally conductive layer 16 may include, for example, multi-walled carbon nanotubes, aluminum oxide, zinc oxide, titanium oxide, graphene, graphite, or boron nitride, or a combination thereof, or other high thermal conductivity material. The third heat conductive layer 16 of the present embodiment is exemplified by a multiwall carbon nanotube. In some embodiments, the third thermally conductive layer 16 may include a plurality of nanotubes 161 (e.g., carbon nanotubes) with the axial direction of the nanotubes 161 being perpendicular to the surface of the second thermally conductive layer 14. Here, the growth direction of the carbon nanotubes may be controlled by using the process conditions such that the axial direction of the grown carbon nanotubes is perpendicular to the planar direction of, for example, the graphene microchip (the second thermally conductive layer 14).

In some embodiments, the coverage of the third thermally conductive layer 16 over the surface of the second thermally conductive layer 14 may be greater than or equal to 0.001% and less than or equal to 100% (0.001% coverage 100%,100% meaning coverage over the entire surface). In some embodiments, the coverage of the third heat conductive layer 16 over the surface of the second heat conductive layer 14 may be greater than or equal to 5% and less than or equal to 100% (5% coverage less than or equal to 100%), such as 7%, 10%, 12%, 15%, 20%, 25%, 30%, …, 90%, etc.; in some embodiments, the coverage of the third heat conductive layer 16 over the surface of the second heat conductive layer 14 may be greater than or equal to 0.001% and less than or equal to 5% (0.001% coverage less than or equal to 5%), such as, but not limited to, 0.005%, 0.01%, 0.02%, 0.5%, 1%, …%, or 3%, etc. In addition, the features described above for the third thermally conductive layer 16 to cover the surface of at least a portion of the second thermally conductive layer 14 and its coverage rate can also be applied to other embodiments of the present invention.

In the present embodiment, the third heat conductive layer 16 (carbon nanotubes) is disposed on the second heat conductive layer 14, so as to enhance the rate of the working fluid 15 entering/exiting the second heat conductive layer 14 and the first heat conductive layer 12, and further increase the heat conduction efficiency. In addition to increasing the heat conduction efficiency, the third heat conduction layer 16 (carbon nanotubes) of the present embodiment can also increase the coverage of the second heat conduction layer 14 with the first heat conduction layer 12 (graphene layer). Wherein, the increased coverage can further improve the hydrophilicity of the second heat conduction layer 14 and the first heat conduction layer 12 (graphene material), and simultaneously improve the protection of the metal microstructure 13, so as to avoid corrosion or oxidation. The higher the hydrophilicity, the smaller the contact angle (contact angle), the more easily the working fluid 15, such as water and water vapor, in the closed cavity 111 can be continuously attached to the surface of the graphene/carbon nanotube, so that the water is easier to evaporate, the water vapor is easier to condense, the cycle efficiency can be increased, and the heat conduction efficiency can be further improved.

In addition, the heat conduction structure includes the characteristic of the third heat conduction layer 16, for example, the characteristic of stepwise or asymptotic thickness and variation can be used with other embodiments of the present invention, so that the thickness sum of the first heat conduction layer 12, the second heat conduction layer 14 and the third heat conduction layer 16 near the heat source end H can be greater than the thickness sum of the first heat conduction layer 12, the second heat conduction layer 14 and the third heat conduction layer 16 far from the heat source end H; alternatively, the first 12, second 14, third 16 heat conductive layers in the first section S1 of the at least two sections are at least partially different from the materials of the first 12, second 14, third 16 heat conductive layers in the second section S2.

In addition, please refer to fig. 3A and 3B, which are different cross-sectional views of a heat conduction structure according to another embodiment of the present invention.

The heat conductive structure 1B of fig. 3A and 3B is substantially the same as the heat conductive structure 1a of fig. 2. The main difference from the heat conduction structure 1a is that the first heat conduction layer 12 of the heat conduction structure 1B of the present embodiment is disposed on the bottom surface B and the top surface T of the closed cavity 111, respectively. Therefore, as shown in fig. 3A, the bottom surface B and the top surface T of the closed cavity 111 have mirror structures, respectively. Wherein, the first heat conductive layer 12, the metal microstructure 13, the second heat conductive layer 14 and the third heat conductive layer 16 are sequentially arranged on the bottom surface B from bottom to top, and the third heat conductive layer 16, the second heat conductive layer 14, the metal microstructure 13 and the first heat conductive layer 12 are sequentially arranged on the top surface T from bottom to top (the reference numerals "S" "," S '"in fig. 3B represent the stacked structures of the third heat conductive layer 16, the second heat conductive layer 14, the metal microstructure 13 and the first heat conductive layer 12, respectively, and the two third heat conductive layers 16 of the stacked structure S, S' are opposite). Since the bottom surface B and the top surface T of the heat conducting unit 11 are respectively provided with the stacking structures S, S', the condensed liquid working fluid 15 can flow back to the heat source end H (the flow direction D2) along the metal microstructures 13 of the bottom surface B and the top surface T, so as to increase the amount of the condensed liquid working fluid 15 and further increase the heat conduction efficiency.

In addition, please refer to fig. 3C, which is a schematic cross-sectional view of a heat conduction structure according to another embodiment of the present invention.

The heat conductive structure 1C of fig. 3C is substantially the same as the heat conductive structure 1B of fig. 3B. The main difference from the heat conduction structure 1b is that the inner side surface of the closed cavity 111 of the heat conduction structure 1c of the present embodiment may further include a fourth heat conduction layer 17 in addition to the stacked structure S, S ', and the fourth heat conduction layer 17 is disposed at a position without the stacked structure S, S' in the inner side surface of the closed cavity 111. In other words, the fourth heat conduction layer 17 of the present embodiment is disposed on two opposite sidewalls of the closed cavity 111 and does not overlap the stacked structure S, S'. Of course, the fourth heat conductive layer 17 may also have partial overlap with the stacked structure S, S' due to process tolerances, and is not limited. The fourth heat conducting layer 17 may have the same material as the first heat conducting layer 12, the second heat conducting layer 14 or the third heat conducting layer 16, preferably, graphene or carbon nanotubes, so as to increase the coverage rate of the heat conducting unit 11, make the material (e.g. copper) of the heat conducting unit 11 have better hydrophilicity, further increase the heat conducting effect, and meanwhile, the fourth heat conducting layer 17 may improve the protection of the heat conducting unit 11 and avoid the corrosion or oxidation of the heat conducting unit 11.

In some embodiments, the fourth thermally conductive layer 17 covers at least a portion of the surface where the stacked structure S, S' is absent from the two opposite side walls of the inner side surface of the closed cavity 111, and the coverage thereof may be 0.01% or more and 100% or less (0.01% or less and 100% or less). In some embodiments, the coverage of the fourth thermally conductive layer 17 at the position having no stacked structure S, S' in the two opposite side walls of the inner side surface of the closed cavity 111 may be 0.02% or more and 5% or less (0.02% or less coverage 5% or less), such as 0.05%, 0.5%, 1%, 1.5%, 2%, 3%, or 4.5%, etc., or other percentages, without limitation.

In a different embodiment, if only the bottom surface B has the form of the stacked structure S (e.g. fig. 1C), the fourth heat conducting layer 17 may be disposed at a position of the inner side surface of the closed cavity 111 where the stacked structure S is not present, that is, on two opposite side walls of the inner side surface of the closed cavity 111 and the top surface T thereof. In addition, the features of the fourth thermally conductive layer 17 are included in the thermally conductive structure and may be used in other embodiments of the present invention.

In addition, other technical features of the heat conducting structures 1a, 1b, 1c may refer to the same components of the heat conducting structure 1, and will not be described herein.

In addition, in the

heat conduction structures

1, 1a, 1b, 1c, in the direction along the X-X cutting line (i.e., the long axis direction of the heat conduction unit 11), the above-mentioned stacked structure S (or S, S') may be divided into at least two sections, which may include a first section and a second section, wherein the materials of the first heat conduction layer 12 and the second heat conduction layer 14 in the first section are at least partially different from the materials of the first heat conduction layer 12 and the second heat conduction layer 14 in the second section; alternatively, the materials of the first, second, and third heat

conductive layers

12, 14, 16 in the first section are at least partially different from the materials of the first, second, and third heat

conductive layers

12, 14, 16 in the second section.

For example, taking fig. 1C as an example, the stacked structure S can be divided into a first section S1 closest to the heat source end H and a second section S2 closest to the cooling end C (adjacent to the first section S1), wherein the materials of the first heat conductive layer 12 and the second heat conductive layer 14 in the first section S1 are respectively graphene and graphene, but the materials of the first heat conductive layer 12 and the second heat conductive layer 14 in the second section S2 are respectively graphene and carbon nanotube; as long as the material of any one of the materials of the first and second heat

conductive layers

12, 14 in the two sections is different, i.e., the above-described condition that the materials of the first and second heat

conductive layers

12, 14 in the at least two sections are at least partially different is satisfied.

In addition, taking fig. 3B as an example, the stacked structure S, S 'can be divided into a first section S1, S1' closest to the heat source end H and a second section S2, S2 '(adjacent to the first section S1, S1') closest to the cooling end C, wherein the materials of the first heat conductive layer 12, the second heat conductive layer 14, and the third heat conductive layer 16 in the first section S1, S1 'are, for example, graphene, and carbon nanotube, respectively, but the materials of the first heat conductive layer 12, the second heat conductive layer 14, and the third heat conductive layer 16 in the second section S2, S2' are, for example, graphene, and graphene, respectively; alternatively, the materials of the first heat conductive layer 12, the second heat conductive layer 14, and the third heat conductive layer 16 in the second sections S2, S2' are, for example, graphene, carbon nanotubes, and graphene, respectively, so long as the materials of any one of the materials of the first heat conductive layer 12, the second heat conductive layer 14, and the third heat conductive layer 16 in the two sections are different, that is, the materials of the first heat conductive layer 12, the second heat conductive layer 14, and the third heat conductive layer 16 in the at least two sections are at least partially different. The above materials are examples only and are not intended to limit the present invention.

Of course, in different embodiments, the stacked structure S or the stacked structure S, S' can also be divided into three or more sections, and the materials of the first, second and third heat

conductive layers

12, 14, 16 in at least two of the three or more sections are at least partially different. Furthermore, the first heat conductive layer 12 and the second heat conductive layer 14 in at least two sections of the stacked structure have different material characteristics, or the first heat conductive layer 12, the second heat conductive layer 14 and the third heat conductive layer 16 in at least two sections have different material characteristics, which can also be applied to other embodiments of the present invention, including the stepwise-changing heat conductive structure of fig. 1F, or the asymptotically-changing heat conductive structure.

Fig. 4 is a schematic diagram of a mobile device according to an embodiment of the invention. As shown in fig. 4, the mobile device 2 of the present embodiment is a mobile phone. The mobile device 2 includes a heat source HS and a heat conducting structure 3, wherein the heat conducting structure 3 is disposed inside the mobile device 2, and one end (i.e. a heat source end) of the heat conducting structure can contact the heat source HS to guide and transfer heat generated by the heat source to the cooling end, and then is dissipated to the outside through, for example, a back cover (not shown) of the mobile device 2. The heat conducting structure 3 may be the

heat conducting structure

1, 1a, 1b, or 1c described above, or a variation thereof, and the detailed description is omitted herein. In addition, the heat source of the present embodiment is exemplified by the CPU of the mobile device 2. In some embodiments, the CPU temperature of the mobile device 2 is relatively high, possibly exceeding 100 ℃, and the heat conduction structure of the above embodiment of the present invention is suitable for conducting heat and dissipating heat. In addition, in various embodiments, the heat source may also be a memory chip (card), a display chip (card), a panel, or a power element of the mobile device 2, or other elements, units, or components that generate high temperature heat.

It should be further noted that, in an experimental example of the heat conduction structure of the present invention, the working fluid 15 is, for example, water, the heat source temperature is, for example, 65 ℃, the materials of the first heat conduction layer 12 and the second heat conduction layer 14 are, for example, graphene, respectively, with thicknesses of between 0.6 nanometer (nm) and 1.5nm, respectively, the material of the third heat conduction layer 16 is, for example, carbon nanotube, with thicknesses of between 2nm and 3nm, the metal microstructure 13 is, for example, copper mesh, and with thicknesses of less than 80 micrometers (μm), for example. The comparison of the temperature difference between the heat conduction structure proposed in this embodiment and the well-known temperature equalization plate (without the first heat conduction layer, the second heat conduction layer, the third heat conduction layer) can be referred to in the following table:

It can be found from the above table that if a well-known temperature equalizing plate (the first substrate has only a copper mesh and no first heat conduction layer, second heat conduction layer and third heat conduction layer) is used, the temperature difference between the heat source end and the cooling end can reach 2.7 ℃, but in the heat conduction structure of an embodiment of the present invention, when the lower substrate has a carbon nanotube/graphene/copper mesh/graphene structure, the temperature difference between the heat source end and the cooling end is only 1.5 ℃, and when the lower substrate and the upper substrate have graphene/copper mesh/graphene/carbon nanotube, the temperature difference between the heat source end and the cooling end is only 1.2 ℃, which proves that the heat conduction structure provided by the embodiment of the present invention has a higher heat conduction efficiency, so that the temperature equalizing effect is better.

In addition, in a comparative experimental example of the present invention for a long period of time, two different heat conductive structures are shared, which are referred to herein as "first heat conductive structure" and "second heat conductive structure". By "different thermally conductive structures" is meant herein that the first, second and third thermally conductive layers within them are of different thickness and are otherwise identical (e.g., material, dimensions). The first heat conductive layer and the second heat conductive layer are respectively graphene layers, the material of the third heat conductive layer is carbon nanotubes, and the metal microstructure is a copper mesh (with a constant thickness) for example.

In the first heat conduction structure, the sum of the thicknesses of the first heat conduction layer, the second heat conduction layer and the third heat conduction layer is sequentially 500 nanometers (nm), 300nm, 50nm and 5nm from different sections from the adjacent heat source end to the far heat source end; in the second heat conduction structure, the thicknesses of the first heat conduction layer, the second heat conduction layer and the third heat conduction layer are unchanged, and the thicknesses of the first heat conduction layer, the second heat conduction layer and the third heat conduction layer are 5nm from the adjacent heat source end to the far heat source end. The first heat conducting structure and the second heat conducting structure have the first heat conducting layer, the second heat conducting layer and the third heat conducting layer, so that compared with the conventional temperature equalizing plate (without the first heat conducting layer, the second heat conducting layer and the third heat conducting layer), the temperature difference between the heat source end and the cooling end of the first heat conducting structure and the temperature difference between the heat source end and the cooling end of the second heat conducting structure are lower than those of the conventional temperature equalizing plate, and the heat conducting structure has higher heat conducting efficiency, so that the temperature equalizing effect is better.

In addition, after the first heat conduction structure and the second heat conduction structure are simultaneously contacted with the heat source (for example, 150 ℃ C.) and are in heat balance, the temperature of the cooling end of the first heat conduction structure is 149.1 ℃ (the temperature difference between the heat source end and the cooling end is 0.9 ℃ C.), and the temperature of the cooling end of the second heat conduction structure is 147.6 ℃ (the temperature difference between the heat source end and the cooling end is 2.4 ℃ C.). After 30 days, the cooling end temperature of the first heat transfer structure was 148.6deg.C (temperature difference 1.4 deg.C), and the cooling end temperature of the second heat transfer structure was 146.7deg.C (temperature difference 3.3 deg.C). After 90 days, the cooling end temperature of the first heat transfer structure was 147.9 ℃ (temperature difference was 2.1 ℃), and the cooling end temperature of the second heat transfer structure was 145.2 ℃ (temperature difference was 4.8 ℃).

Two features can be seen from the above, the first: under the same time, the temperature equalizing effect of the first heat conduction structure is better than that of the second heat conduction structure, and the thickness sum of the first heat conduction layer, the second heat conduction layer and the third heat conduction layer which are adjacent to the heat source end is larger than that of the heat source end, so that the heat conduction structure has better heat conduction efficiency; second feature: the material and adhesion of graphene (first heat conduction layer, second heat conduction layer) will deteriorate due to long time (for example, 90 days), so that the temperature difference between the heat source end and the cooling end becomes large, and the heat conduction efficiency is reduced, however, if the thickness sum of the first heat conduction layer, the second heat conduction layer and the third heat conduction layer close to the heat source end is larger than that of the first heat conduction structure far from the thickness sum of the heat source end, the degradation degree of graphene is smaller, the damage of the material and the adhesion thereof can be delayed, and the degree of heat conduction efficiency deterioration is smaller, which proves the advantages.

Hereinafter, the process of manufacturing the heat conductive structure of the present application will be described again. Fig. 5A and fig. 5B are schematic views of different manufacturing processes of the heat conduction structure according to the present invention, fig. 6A to fig. 6E are schematic views of a manufacturing process of the heat conduction structure according to an embodiment of the present invention, and fig. 7A and fig. 7B are schematic views of a portion of another manufacturing process of the heat conduction structure according to an embodiment of the present invention.

As shown in fig. 5A, the method of manufacturing the heat conductive structure may include steps S01 to S05. Here, step S01 is first performed: the first heat conductive layer 12 is formed on the first substrate 10a and/or the second substrate 10 b. As shown in fig. 6A, this embodiment is exemplified by forming a first heat conductive layer 12 (e.g., a graphene layer) on the bottom surface B of the first substrate 10a that is concave. In various embodiments, the first heat conductive layer 12 may be formed on the first substrate 10a, the first substrate 10a and the second substrate 10b, or the first substrate 10a and the second substrate 10 b. In some embodiments, the first thermally conductive layer 12 may be formed on the first substrate 10a and/or the second substrate 10b using, for example, chemical vapor deposition (chemical vapor deposition, CVD), or spray, or coating, or adhesive, or other suitable means. In some embodiments, the first substrate 10a and the second substrate 10b may be semi-cylindrical (both combined into a heat pipe), respectively, and the first heat conductive layer 12 may be formed on the inner side surface of the first substrate 10a and/or the second substrate 10b (i.e. the heat pipe has the first heat conductive layer 12 on the inner side surface).

Next, step S02 is performed: a metal microstructure 13 is formed on the first substrate 10a and/or the second substrate 10b such that the first heat conductive layer 12 is located between the metal microstructure 13 and the first substrate 10a and/or the second substrate 10 b. As shown in fig. 6B, in this embodiment, a metal microstructure 13 (e.g. a copper mesh) is formed on the first substrate 10a, so that the first heat conductive layer 12 may be located between the metal microstructure 13 and the first substrate 10 a. In some embodiments, the metal microstructures 13 may be disposed on the first substrate 10a and/or the second substrate 10b by, for example, a thermal process, a thermal sintering process, or other suitable method, so that the first heat conductive layer 12 covers at least a portion of the lower surface of the metal microstructures 13, and the first heat conductive layer 12 is located between the metal microstructures 13 and the first substrate 10a and/or the second substrate 10 b.

After that, step S03 is performed: as shown in fig. 6C, a second heat conductive layer 14 is formed on a side of the metal microstructure 13 remote from the first heat conductive layer 12. In some embodiments, the second thermally conductive layer 14 (e.g., a graphene layer) may be formed on the metal microstructure 13 by, for example, chemical Vapor Deposition (CVD), electrical bonding, or adhesive bonding, or other suitable method, such that the second thermally conductive layer 14 covers at least a portion of the upper surface of the metal microstructure 13, and such that the metal microstructure 13 is located between the second thermally conductive layer 14 and the first thermally conductive layer 12.

Next, step S04 is performed: as shown in fig. 6D, the first substrate 10a and the second substrate 10b are combined to form the heat conducting unit 11, wherein the heat conducting unit 11 forms the closed cavity 111, wherein before the step of combining the first substrate 10a and the second substrate 10b, further comprising forming a fourth heat conducting layer 17 (not shown) in the inner side surface of the closed cavity 111 at a position without the first heat conducting layer 12, the metal microstructure 13 and the second heat conducting layer 14. Here, the sides of the first substrate 10a and the second substrate 10b may be connected together by, for example, a soldering or an adhesion process to form the heat conductive unit 11 having the closed cavity 111. However, in order to be filled with the working fluid 15 later, at least one notch O needs to be left on the side edge (e.g., on the second substrate 10 b) of the heat conducting unit 11, so that the working fluid 15 can be injected from the notch O. In some embodiments, the notch O is located at a junction of the sides of the heat conducting unit 11, for example, but not limited to.

After that, step S05 is performed: the working fluid 15 is injected into the closed cavity 111 through the notch O of the heat conducting unit 11. In some embodiments, working fluid 15 may be injected into closed cavity 111 using, for example, but not limited to, an injection needle extending into gap O. Thereafter, the notch O is sealed to obtain the heat conductive structure 1 of fig. 6E (the structure is the same as that of fig. 1B).

In some embodiments, before the step S04 of combining the first substrate 10a and the second substrate 10b, the manufacturing method of the present invention may further include the following steps: forming a third thermally conductive layer 16 (see thermally conductive structure 1a of fig. 2) on a side of the second thermally conductive layer 14 remote from the metal microstructure 13; in some embodiments, before the step of combining the first substrate 10a and the second substrate 10b, the manufacturing method may further include the steps of: a fourth heat conductive layer 17 is formed in the inner side surface of the closed cavity 111 at a position where the first heat conductive layer 12, the metal microstructure 13, the second heat conductive layer 14, and the third heat conductive layer 16 are not provided; then, the steps S04 and S05 are performed. In some embodiments, the third thermally conductive layer 16 may be formed by, for example, growing multi-walled carbon nanotubes on the second thermally conductive layer 14 using, for example, an arc discharge process, a laser vaporization process, or a chemical vapor deposition process. Preferably, the axial direction of the grown carbon nanotubes is perpendicular to the surface of the second thermally conductive layer 14.

In addition, as shown in fig. 5B, another method of manufacturing the heat conductive structure according to an embodiment of the present invention may include steps T01 to T05. First, step T01 is performed: as shown in fig. 7A, a first thermally conductive layer 12 is first formed on a metal microstructure 13. Here, the first heat conductive layer 12 may be formed on the lower side of the metal microstructure 13 by, for example, chemical Vapor Deposition (CVD), electrical bonding, or adhesive bonding, so as to cover at least a portion of the lower surface of the metal microstructure 13. Next, as shown in fig. 7B, step T02 is performed: a second heat conductive layer 14 is formed on a side of the metal microstructure 13 away from the first heat conductive layer 12 to cover at least a portion of the upper surface of the metal microstructure 13, such that the metal microstructure 13 is sandwiched between the second heat conductive layer 14 and the first heat conductive layer 12. In some embodiments, the step T01 and the step T02 may be performed simultaneously, that is, the second heat conduction layer 14 and the first heat conduction layer 12 may be formed on the upper surface and the lower surface of the metal microstructure 13 in one process.

Thereafter, step T03 is performed: the metal microstructures 13 having the first and second heat

conductive layers

12 and 14 are disposed on the first and/or

second substrates

10a and 10b such that the first heat conductive layer 12 is located between the metal microstructures 13 and the first and/or

second substrates

10a and 10 b. Referring to fig. 6C, the metal microstructure 13 having the first heat conductive layer 12 and the second heat conductive layer 14 is disposed on the bottom surface B of the first substrate 10a with the first heat conductive layer 12 between the metal microstructure 13 and the first substrate 10 a.

Next, referring to fig. 6D, step T04 is performed: the first substrate 10a and the second substrate 10b are combined to form the heat conducting unit 11, wherein the heat conducting unit 11 forms the closed cavity 111, wherein before the step of combining the first substrate 10a and the second substrate 10b, further comprising forming a fourth heat conducting layer 17 (not shown) in the inner side surface of the closed cavity 111 at a position without the first heat conducting layer 12, the metal microstructure 13 and the second heat conducting layer 14. Thereafter, please refer to fig. 6E, and step T05 is performed: the working fluid 15 is injected into the closed cavity 111 through the notch O of the heat conducting unit 11. Thereafter, the notch O is sealed again to obtain the heat conductive structure 1.

Likewise, in some embodiments, before the step T04 of combining the first substrate 10a and the second substrate 10b, the manufacturing method of the present invention may further include the following steps: forming a third thermally conductive layer 16 (see thermally conductive structure 1a of fig. 2) on a side of the second thermally conductive layer 14 remote from the metal microstructure 13; in addition, before the step of combining the first substrate 10a and the second substrate 10b, the manufacturing method may further include the steps of: a fourth heat conductive layer 17 is formed in the inner side surface of the closed cavity 111 at a position where the first heat conductive layer 12, the metal microstructure 13, the second heat conductive layer 14, and the third heat conductive layer 16 are not provided; thereafter, the steps T04 and T05 are performed similarly.

In addition, other technical features of the method for manufacturing a heat conduction structure are described in detail in the foregoing, and are not described herein again.

It is further mentioned that, in the structure and the process of the above embodiment of the present invention, the first heat conduction layer 12 and the second heat conduction layer 14 are specifically formed on two sides of the metal microstructure 13 by two different processes, so that the two sides of the metal microstructure 13 are deliberately and respectively covered with the first heat conduction layer 12 and the second heat conduction layer 14 (the first heat conduction layer 12 and the second heat conduction layer 14 are the film layers generated by different processes, but the materials may be the same or different), which is different from the structure obtained by forming the graphene layer on the upper side of the copper microstructure by one process in the well-known process; in addition, when the two sides of the metal microstructure 13 are correspondingly covered with the first heat conduction layer 12 and the second heat conduction layer 14, the hydrophilicity of the metal microstructure 13, the circulation efficiency of the working fluid 15, the temperature equalizing effect of the heat conduction structure and the heat conduction effect are better than those of the structure manufactured by the well-known process.

In summary, in the heat conduction structure, the manufacturing method thereof, and the mobile device of the present invention, the first heat conduction layer and the second heat conduction layer are disposed on two sides of the metal microstructure in the heat conduction structure, and the fourth heat conduction layer is disposed in the inner surface of the closed cavity, and is not disposed at the positions of the first heat conduction layer, the metal microstructure, and the second heat conduction layer, so that hydrophilicity of the metal microstructure can be increased, and a backflow rate of the liquid working fluid in the metal microstructure can be increased, so that a circulation efficiency of the working fluid can be increased, and a uniform temperature effect and a heat conduction effect of the heat conduction structure are better. Therefore, the heat conduction structure of the invention has higher heat conduction efficiency, and can rapidly conduct heat energy generated by a heat source, and is also suitable for the heat dissipation requirement of the light and thin mobile device.

In some embodiments, the heat conductive structure of the present invention may further include a third heat conductive layer disposed on a side of the second heat conductive layer away from the metal microstructure, wherein the third heat conductive layer may increase coverage and hydrophilicity, and may also increase the protection of the metal microstructure from corrosion or oxidation, in addition to increasing the heat conductive efficiency of the heat conductive structure.

The foregoing is by way of example only and is not limiting. Any equivalent modifications or variations to the present invention without departing from the spirit and scope of the present invention are intended to be included in the claims of the present application.

Claims

1. A thermally conductive structure, comprising:

a heat conducting unit forming a closed cavity, the closed cavity having a bottom surface and a top surface opposite to each other;

a first thermally conductive layer disposed on the bottom surface and/or the top surface of the closed cavity;

a metal microstructure disposed on the first thermally conductive layer such that the first thermally conductive layer is located between the metal microstructure and the bottom surface and/or the top surface;

a second heat conducting layer arranged on one side of the metal microstructure far away from the first heat conducting layer;

a third heat conducting layer disposed on a side of the second heat conducting layer remote from the metal microstructure;

a fourth heat conductive layer disposed in the closed cavity inner side surface at a position without the first heat conductive layer, the metal microstructure, the second heat conductive layer, and the third heat conductive layer; and

and the working fluid is arranged in the closed cavity of the heat conduction unit.

2. The thermally conductive structure of claim 1, wherein the first thermally conductive layer or the second thermally conductive layer overlies at least a portion of a surface of the metal microstructure.

3. The thermally conductive structure of claim 1, wherein the coverage of the first thermally conductive layer or the second thermally conductive layer over the metal microstructured surface is 5% or more and 100% or less.

4. The heat conducting structure of claim 1, wherein the first heat conducting layer, the metal microstructure, and the second heat conducting layer form a stacked structure that is divided into at least two sections in a long axis direction of the heat conducting unit, the at least two sections including a first section and a second section, the first heat conducting layer, the second heat conducting layer in the first section being at least partially different from the first heat conducting layer, the second heat conducting layer in the second section.

5. The thermally conductive structure of claim 1, wherein the metallic microstructure is in the form of a metallic mesh, a metallic powder, or metallic particles, or a combination thereof.

6. The thermally conductive structure of claim 1, wherein the material of the first thermally conductive layer or the second thermally conductive layer comprises graphene, graphite, carbon nanotubes, aluminum oxide, zinc oxide, titanium oxide, or boron nitride, or a combination thereof.

7. The heat conducting structure of claim 1, wherein the first heat conducting layer, the metal microstructure, the second heat conducting layer, and the third heat conducting layer form a stacked structure that is divided into at least two sections including a first section and a second section in a long axis direction of the heat conducting unit, the first heat conducting layer, the second heat conducting layer, the third heat conducting layer in the first section being at least partially different from the first heat conducting layer, the second heat conducting layer, and the third heat conducting layer in the second section.

8. The thermally conductive structure of claim 1, wherein the third thermally conductive layer comprises a plurality of nanotubes with an axial direction perpendicular to a surface of the second thermally conductive layer.

9. The heat conducting structure of claim 1, wherein the fourth heat conducting layer covers in the enclosed cavity inner side surface, without coverage of the first heat conducting layer, the metal microstructure, the second heat conducting layer, and the third heat conducting layer being 0.01% or more and 100% or less.

10. A mobile device, comprising:

a heat source; and

a thermally conductive structure according to any one of claims 1 to 9, wherein one end of the thermally conductive structure contacts the heat source.

11. A method of manufacturing a thermally conductive structure, comprising the steps of:

forming a first heat conductive layer on the first substrate and/or the second substrate;

forming a metal microstructure on the first substrate and/or the second substrate such that the first thermally conductive layer is located between the metal microstructure and the first substrate and/or the second substrate;

forming a second heat conducting layer on a side of the metal microstructure away from the first heat conducting layer;

forming a third thermally conductive layer on a side of the second thermally conductive layer remote from the metal microstructure;

combining the first substrate and the second substrate to form a thermally conductive unit, wherein the thermally conductive unit forms a closed cavity, wherein prior to the step of combining the first substrate and the second substrate, further comprising forming a fourth thermally conductive layer in an interior surface of the closed cavity at a location that does not have the first thermally conductive layer, the metal microstructure, the second thermally conductive layer, and the third thermally conductive layer; and

And injecting working fluid into the closed cavity through the notch of the heat conducting unit.

12. A method of manufacturing a thermally conductive structure, comprising the steps of:

forming a first thermally conductive layer over the metal microstructure;

disposing the metal microstructures having the first and second heat conductive layers on a first and/or second substrate with the first heat conductive layer between the metal microstructures and the first and/or second substrate;

13. The manufacturing method according to claim 11 or 12, wherein the fourth heat conductive layer covers in the closed cavity inner side surface, without coverage of the first heat conductive layer, the metal microstructure, the second heat conductive layer, and the third heat conductive layer, is 0.01% or more and 100% or less.