Vapor chamber and electronic equipment

Abstract

The invention relates to a vapor chamber and electronic equipment. The vapor chamber comprises a first cover plate and a second cover plate which are oppositely arranged, wherein a sealing cavity is formed between the first cover plate and the second cover plate; the liquid absorbing core is arranged between the first cover plate and the second cover plate, the liquid absorbing core comprises a liquid absorbing silk screen, the liquid absorbing silk screen comprises warp and weft which are crossed transversely and longitudinally, the included angle between the warp and a preset bending shaft and the included angle between the weft and the preset bending shaft are both smaller than 90 degrees, and the vapor chamber can be bent along the preset bending shaft.

Description

Technical Field

[0001] The present application relates to the technical field of electronic equipment, and in particular to a heat spreader and electronic equipment. Background Art

[0002] Mobile electronics, flexible electronics, computing devices, graphics processors and other devices have an increasingly urgent need for heat dissipation, and it is necessary to add heat dissipation components to existing devices to maintain product performance and improve reliability. Currently, there are two types of heat dissipation devices: active heat dissipation devices with power devices (such as fans or blowers) and passive heat dissipation devices. Passive heat dissipation devices do not rely on power devices and are considered more reliable than active solutions.

[0003] As an efficient passive heat dissipation element, the heat spreader has the characteristics of low thermal resistance and uniform temperature, and is widely used in heat dissipation devices of high heat flux density equipment. The heat spreader is a vacuum cavity with a capillary structure on the inner wall and injected with a working fluid. It uses the latent heat of phase change of the internal working fluid to achieve rapid heat transfer and diffusion, and can achieve efficient heat dissipation in a very small space. In the related art, the heat spreader includes a first cover plate and a second cover plate that are relatively arranged, and a liquid wick and a support column arranged between the first cover plate and the second cover plate, and one end of the support column is in contact with the liquid wick. A sealed cavity is formed between the first cover plate and the second cover plate, and the working fluid is filled in the sealed cavity, and the liquid wick has a capillary structure. Among them, the capillary structure of the liquid wick can be formed by at least one of the following methods: weaving, sintering, and etching.

[0004] Flexible vapor chambers have good flexibility and adaptability, and can meet the heat dissipation requirements of different shapes and sizes. With the further miniaturization and integration of electronic devices, the demand for flexible vapor chambers is increasing. However, the design and manufacturing of flexible vapor chambers still face many challenges. How to improve the bending performance and thermal conductivity of flexible vapor chambers has become an urgent problem to be solved. Summary of the invention

[0005] The present application provides a vapor chamber and an electronic device, which are used to improve the bending performance and thermal conductivity of the vapor chamber.

[0006] In a first aspect, a heat spreader is provided, comprising: a first cover plate and a second cover plate arranged opposite to each other, a sealed cavity formed between the first cover plate and the second cover plate; and a liquid absorbent core arranged between the first cover plate and the second cover plate, wherein the liquid absorbent core comprises a liquid absorbent mesh, the liquid absorbent mesh comprises warp threads and weft threads that cross each other horizontally and vertically, the angles between the warp threads and the weft threads and a preset bending axis are both less than 90°, and the heat spreader can be bent along the preset bending axis.

[0007] In a second aspect, an electronic device is provided, comprising: a heat source; and the above-mentioned heat spreader, wherein a first cover plate of the heat spreader is disposed close to the heat source. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0009] Figure 1 A schematic diagram of a partial structure of a vapor chamber in some embodiments of the present application;

[0010] Figure 2 A schematic diagram of a partial structure of a vapor chamber in some embodiments of the present application;

[0011] Figure 3 It is a partial enlarged schematic diagram of the liquid absorbent core in some embodiments of the present application;

[0012] Figure 4 It is a partially enlarged schematic diagram of a liquid-absorbing core in the related art;

[0013] Figure 5 A schematic diagram of the distribution of support columns in some embodiments of the present application;

[0014] Figure 6 This is a schematic diagram of the structure of the support column on the second cover plate in some embodiments of the present application;

[0015] Figure 7 This is a schematic diagram of the structure of the support column on the second cover plate in some embodiments of the present application;

[0016] Figure 8 This is a schematic diagram of the structure of the support column on the second cover plate in some embodiments of the present application;

[0017] Fig. 9 A schematic diagram of the use of a vapor chamber in some embodiments of the present application;

[0018] Fig.10 A schematic diagram of the use of a vapor chamber in some embodiments of the present application;

[0019] Fig.11 A schematic diagram of the use of a vapor chamber in some embodiments of the present application;

[0020] Fig.12 This is a schematic diagram of the structure of the thermally conductive film in some embodiments of the present application;

[0021] Fig.13 A schematic diagram of the use of a vapor chamber in some embodiments of the present application;

[0022] Fig.14Schematic diagram of the assembly of the heat sink in some embodiments of the present application. DETAILED DESCRIPTION

[0023] The technical solution of the present application will be described clearly and in detail below in conjunction with the drawings of the embodiments of the present application. Obviously, the embodiments described below are part of the embodiments of the present application rather than all of the embodiments, and are only used to more clearly illustrate the technical solution of the present application. Therefore, they are only used as examples, and the protection scope of the present application cannot be limited by this. Based on the described embodiments of the present application, all other embodiments that can be obtained by those skilled in the art without creative work belong to the scope of protection of the present application.

[0024] Unless otherwise defined, all technical and scientific terms used herein shall have the meanings commonly understood by technicians in the technical field of this application; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the embodiments of this application and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the embodiments of this application are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the embodiments of this application, unless otherwise stated, "multiple" means more than two.

[0025] The electronic device in the embodiments of the present application may be, but is not limited to, a cellular phone, a smart phone, a tablet computer, a wearable device, a desktop computer, or a laptop computer.

[0026] Electronic devices generate heat when they are working. As the heat accumulates, the temperature of the device rises, which will affect the performance of the device and even cause failure and damage. Therefore, effective technical means are needed to solve the heat dissipation problem of electronic devices.

[0027] As a highly efficient passive heat dissipation component, the heat spreader has the characteristics of low thermal resistance and uniform temperature, and is widely used in heat dissipation devices of high heat flux density equipment.

[0028] The vapor chamber is a vacuum cavity with a capillary structure on the inner wall and injected with a working fluid. The heat dissipation principle is as follows: when the heat generated by the heat source is transferred to the vapor chamber, the working fluid near the heat source in the vapor chamber absorbs the heat and vaporizes; when the steam diffuses from the high-temperature area to the low-temperature area, the steam condenses into liquid and releases heat when it contacts the inner wall with a lower temperature; the condensed liquid working fluid returns to the position close to the heat source through the capillary force of the capillary structure, thus completing a heat conduction cycle and forming a bidirectional heat circulation system in which gas and liquid working fluids coexist.

[0029] The liquid surface in the capillary structure is concave, and the concave liquid surface exerts a pulling force (i.e., capillary force) on the liquid below, causing the liquid to rise along the tube wall of the capillary structure. This is the capillary phenomenon. It can be seen that the heat spreader can realize the circulation of the working fluid in the gas-liquid two-phase by using the capillary phenomenon, and realize heat conduction in the two-phase circulation process, thereby achieving the purpose of dissipating heat from the heat source.

[0030] In the related art, the material of the heat spreader is copper and the working medium is water. It is understandable that the heat spreader can also be made of other materials with good thermal conductivity. The working medium can also be other media with gas-liquid two phases that can absorb or dissipate heat when the two phases change.

[0031] A liquid wick may be arranged on the inner wall of the vapor chamber, and the liquid wick provides a capillary structure, wherein the capillary structure of the liquid wick may be formed by at least one of the following methods: weaving, sintering, and etching.

[0032] With the development of foldable display technology, the demand for flexible vapor chambers is increasing. Flexible vapor chambers have good flexibility and adaptability, and can meet the heat dissipation requirements of different shapes and sizes. However, the design and manufacture of flexible vapor chambers still face many challenges, such as thermal failure. After research, it was found that the main reason for the thermal failure of flexible vapor chambers is that the capillary structure is damaged due to the bending of the liquid wick. Therefore, how to improve the bending performance and thermal conductivity of flexible vapor chambers has become an urgent problem to be solved.

[0033] Based on this, a heat spreader is provided in an embodiment of the present application, wherein the liquid absorbent core includes a liquid absorbent mesh, the liquid absorbent mesh includes warp and weft wires that cross horizontally and vertically, and the angles between the warp and weft wires and the preset bending axis are both less than 90°, and the heat spreader can be bent along the preset bending axis. As a result, the outward pulling force caused by the bending is dispersed in two directions along the warp and weft wires, so the anti-bending ability of the liquid absorbent core is greatly improved, and the risk of failure of the liquid absorbent core due to breakage is reduced, thereby improving the bending performance and thermal conductivity of the heat spreader.

[0034] The heat sink in the embodiment of the present application is suitable for any electronic device, especially a foldable electronic device.

[0035] The technical solution of the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0036] According to some embodiments of the present application, Figure 1-Figure 3 As shown, the heat spreader may include: a first cover plate 11, a second cover plate 12 and a liquid wick 13. The first cover plate 11 and the second cover plate 12 are arranged opposite to each other, and a sealed cavity is formed between the first cover plate 11 and the second cover plate 12. The liquid wick 13 is arranged between the first cover plate 11 and the second cover plate 12.

[0037] The absorbent core 13 includes an absorbent mesh, which includes warp threads 131 and weft threads 132 that cross horizontally and vertically, and a capillary structure is formed between the warp threads 131 and weft threads 132 that cross horizontally and vertically. The angles θ between the warp threads 131 and weft threads 132 and the preset bending axis X are both less than 90°, and the heat spreader can be bent along the preset bending axis.

[0038] Therefore, when the vapor chamber is bent along the preset bending axis X, the outward pulling force caused by the bending is perpendicular to the preset bending axis X. By setting the angles θ between the warp 131 and the weft 132 of the absorbent mesh and the preset bending axis X to be less than 90°, the outward pulling force caused by the bending is dispersed into two components f along the warp and weft directions, so the bending resistance of the absorbent core can be greatly improved, and the risk of failure of the absorbent core due to breakage can be reduced, thereby improving the bending performance and thermal conductivity of the vapor chamber.

[0039] like Figure 4 As shown, taking the preset bending axis X being perpendicular to the latitude 132 as an example, at the bending part, since the latitude 132 is fixed by the two ends of the warp 131, when bending along the preset bending axis X, the outward pulling force F brought by the bending is along the direction of the latitude 132. Under the tensile effect of the outward pulling force F, the latitude 132 is easily broken at the bending part and the part 130 near the bending part. In the technical solution of the present application, as Figure 3 As shown, by setting the included angle θ between the preset bending axis X and the warp 131 and the weft 132 to be less than 90° (non-perpendicular), the outward pulling force caused by the bending is dispersed in two directions along the warp and weft, thereby greatly improving the bending resistance of the absorbent core and reducing the risk of failure of the absorbent core due to breakage.

[0040] In some embodiments, the warp 131 and the weft 132 of the liquid absorbent mesh can be arranged vertically. It should be noted that the angle between the warp and the weft of the liquid absorbent mesh can also be an acute angle.

[0041] The angle θ between the preset bending axis X and the warp 131 and the weft 132 can be the same, so that the outward pulling force caused by the bending is evenly dispersed into two equal forces f along the warp and weft directions. Exemplarily, the angle θ between the preset bending axis X and the warp 131 and the weft 132 can be, for example, but not limited to, 45°.

[0042] The first cover plate 11 and the second cover plate 12 may be flexible substrates, so that they can be bent and folded. The materials of the first cover plate 11 and the second cover plate 12 may be glass, polyimide (PI), polyethylene terephthalate (PET), polydimethylsiloxane (PDMS), etc. The first cover plate 11 and the second cover plate 12 may be made of the same material or different materials.

[0043] In some embodiments, the material of the first cover plate 11 and the second cover plate 12 can be glass, which has better airtightness. In this case, the thickness of the first cover plate 11 and the second cover plate 12 can be 5um to 300um, so that the heat spreader has good bending performance. Exemplarily, the thickness of the first cover plate 11 and the second cover plate 12 can be, but is not limited to, 200um.

[0044] In some embodiments, the thickness of the first cover plate 11 and the second cover plate 12 may be 5um to 100um, and the ultra-thin thickness enables the heat spreader to have better bending performance. Exemplarily, the thickness of the first cover plate 11 and the second cover plate 12 may be, but not limited to, 10um. The first cover plate 11 and the second cover plate 12 may be, for example, but not limited to, ultra-thin glass substrates or ultra-thin PI substrates.

[0045] The wick may be disposed on the inner surface of the first cover plate 11 or the second cover plate 12. The inner surface of the first cover plate 11 refers to the surface of the first cover plate 11 close to the second cover plate 12, and the surface of the first cover plate 11 away from the second cover plate 12 is its outer surface. The inner surface of the second cover plate 12 refers to the surface of the second cover plate 12 close to the first cover plate 11, and the surface of the second cover plate 12 away from the first cover plate 11 is its outer surface.

[0046] The absorbent core in the embodiment of the present application includes an absorbent mesh, which may include the following two situations: the first situation: the absorbent mesh covers the entire inner surface of the first cover plate or the second cover plate; the second situation: the absorbent core is a composite structure, and the absorbent mesh is set at least at the bending part of the first cover plate or the second cover plate, and the capillary structure in other areas can be made by sintering and / or etching. In other words, the absorbent core is a composite structure of the absorbent mesh and the sintered absorbent core and / or the grooved absorbent core. Since the outward pulling force caused by the bending is mainly concentrated near the preset bending axis, even if the absorbent mesh in the embodiment of the present application is only set at the bending part of the first cover plate or the second cover plate, the bending resistance of the absorbent core can be greatly improved, and the risk of failure of the absorbent core due to breakage can be reduced, thereby improving the bending performance and thermal conductivity of the heat spreader.

[0047] The heat spreader may have one or more preset bending axes. By adopting the solution in the embodiment of the present application, the bending resistance of the absorbent core can be improved, and the risk of failure of the absorbent core due to breakage caused by bending along any preset bending axis can be reduced.

[0048] The material of the liquid-absorbing screen can be a metal screen, such as a Cu screen, an Al screen, a stainless steel screen, etc., which has good anti-bending ability. It is understandable that the material of the liquid-absorbing screen can also be other materials with good anti-bending ability, such as nylon, spandex, nylon, polyimide, polypropylene, polyethylene, polyester, polyvinyl chloride, polylactic acid, polyhydroxyalkanoic acid, polybutylene succinate, etc.

[0049] Similarly, when the absorbent core is a composite structure of an absorbent mesh and a sintered absorbent core and / or a grooved absorbent core, the material of the sintered absorbent core and the grooved absorbent core may be, but is not limited to, metal, such as Cu, Al, stainless steel, and the like.

[0050] In some embodiments, the wick may be subjected to a hydrophilic treatment so that the working fluid can be more evenly filled in the capillary structure of the wick, thereby improving the effect of cyclic heat conduction.

[0051] The working fluid injected into the heat spreader can be pure water, deionized water, ethanol, ether, etc.

[0052] The first cover plate 11 and the second cover plate 12 can be sealed by laser melting technology or sealant to form a sealed cavity between the first cover plate 11 and the second cover plate 12. When sealing, an injection hole can be reserved, and the sealed cavity of the heat spreader is evacuated through the injection hole, and then a working medium (such as water) is injected into the sealed cavity, and then the vacuum is evacuated again to make the vacuum degree reach between 10^2 and 10^4 Pa, and finally the injection hole is sealed to form a vacuum sealed cavity between the first cover plate 11 and the second cover plate 12.

[0053] According to some embodiments of the present application, Figure 1 and Figure 2 As shown, a plurality of support columns 14 may be provided between the first cover plate 11 and the second cover plate 12, and one end of the support column 14 abuts against the liquid wick 13. By providing a support structure in the sealed cavity, it is beneficial to improve the stability of the sealed cavity, facilitate the free movement of the gas phase working medium in the sealed cavity to achieve heat exchange, and improve the heat conduction effect.

[0054] The support column 14 can be disposed on the first cover plate 11 or the second cover plate 12. The support column 14 can be made of a heat-conducting material, such as a metal material, so that it can also participate in the heat conduction cycle and further improve the heat conduction effect of the heat spreader. The support column 14 can be a single-layer structure or a composite layer structure.

[0055] In some embodiments, when the support column is a composite layer structure, the support column 14 can be disposed on the inner surface of the second cover plate 12 close to the first cover plate 11, and the support column 14 can include a body and a heat-conducting layer disposed on the body. Exemplarily, the body can be made of a non-thermal conductive material, such as photoresist, and a metal heat-conducting layer can be electroplated on the body through an electroplating process to simplify the manufacturing process of the support column and ensure the thermal conductivity of the support column.

[0056] like Figure 5 As shown, a plurality of support columns 14 may be distributed in an array in the sealed cavity of the heat spreader to ensure uniform height of the air chamber in the sealed cavity, thereby improving gas flow efficiency and further improving thermal conductivity.

[0057] In some embodiments, the wick 13 and the support column 14 can be disposed on the first cover plate 11 and the second cover plate 12 respectively to prevent the preparation process of the support column from affecting the wick.

[0058] According to some embodiments of the present application, Figure 6 As shown, the heat spreader includes a bending area 100 and a non-bending area 200, and the preset bending axis is located in the bending area 100. The plurality of support columns 14 include a plurality of first support columns 141 located in the bending area 100 and a plurality of second support columns 142 located in the non-bending area. In the direction parallel to the first cover plate, the number of first support columns 141 per unit area in the bending area 100 is greater than the number of second support columns 142 per unit area in the non-bending area 200. Therefore, by increasing the number of support columns at the bending, the gas flow can be ensured during bending, and the problem of reduced sealing cavity caused by bending can be minimized.

[0059] The first support column 141 and the second support column 142 may be a same-layer structure, and may be manufactured by a photolithography process on the same film layer to simplify the manufacturing process.

[0060] In some embodiments, along a direction parallel to the first cover plate, the number of first support columns 141 per unit area in the bending region 100 increases by 1% to 500% relative to the number of second support columns 142 per unit area in the non-bending region 200 .

[0061] Exemplarily, along a direction parallel to the first cover plate, the number of first support columns 141 per unit area in the bending region 100 increases by 100% relative to the number of second support columns 142 per unit area in the non-bending region 200 .

[0062] In some embodiments, the cross-sectional area of ​​the first support column in the bending region 100 is smaller than the cross-sectional area of ​​the second support column in the non-bending region 200. Thus, the height of the sealed cavity in the bending region is ensured by increasing the number of first support columns to avoid collapse of the sealed cavity. At the same time, the cross-sectional area of ​​the first support columns is reduced to maintain the gas flow efficiency in the sealed cavity, so that the thermal conductivity of the heat sink is less affected after bending.

[0063] Exemplarily, the ratio of the cross-sectional area of ​​the first support column 141 to the cross-sectional area of ​​the second support column 142 ranges from 0.25 to 0.75. For example, the ratio of the cross-sectional area of ​​the first support column to the cross-sectional area of ​​the second support column can be set to 0.5.

[0064] In an exemplary embodiment, the cross section of the first support column may be circular, the diameter of the cross section of the first support column may be, but not limited to, 250 um, and the diameter of the cross section of the second support column may be, but not limited to, 500 um. It should be noted that the cross section of the first support column may also be other shapes, such as square, oval, etc.

[0065] In some embodiments, the ratio between the density of the support columns in the bending region 100 and the density of the support columns in the non-bending region 200 is in the range of 0.01 to 0.99, that is, the density of the support columns in the bending region 100 is less than the density of the support columns in the non-bending region 200. Among them, the density of the support columns in the bending region is the ratio of the sum of the cross-sectional areas of the plurality of first support columns to the area of ​​the bending region, and the density of the support columns in the non-bending region is the ratio of the sum of the cross-sectional areas of the plurality of second support columns to the area of ​​the non-bending region. Thus, by reducing the density of the support columns in the bending region, the gas flow efficiency in the bending region can be maintained, and the influence on the thermal conductivity of the heat spreader after bending can be reduced.

[0066] In some embodiments, the density of the support columns in the bending region can be reduced by increasing the number of the first support columns 141 in the bending region 100 and reducing the cross-sectional area of ​​the first support columns 141, thereby maintaining the gas flow efficiency and maintaining the height of the air chamber in the bending region to prevent the air chamber from collapsing, so that the bending has little effect on the thermal conductivity of the heat spreader. It is understandable that the density of the support columns in the bending region can also be reduced by only reducing the cross-sectional size of the first support columns in the bending region.

[0067] It should be noted that increasing or decreasing the number of first support columns in the bending area is relative to the non-bending area of ​​the heat spreader. Similarly, increasing or decreasing the cross-sectional size of the first support columns in the bending area is also relative to the non-bending area of ​​the heat spreader.

[0068] The height and / or cross-sectional surface of the plurality of second support columns 142 in the non-bending region 200 can be consistent to ensure that the air chamber height of the heat spreader is consistent, so as to improve the gas flow efficiency in the air chamber and improve the heat conduction effect. It is understandable that the height and / or cross-sectional surface of the plurality of second support columns in the non-bending region can also be set to be inconsistent according to actual needs.

[0069] According to some embodiments of the present application, Figure 7 As shown, the height of the first support column 141 in the bending area 100 is less than the height of the second support column 142 in the non-bending area 200. Therefore, by reducing the height of the support column in the bending area, the bending performance of the heat spreader can be improved. The height of the support column refers to the length of the support column extending in the direction perpendicular to the second cover plate 12.

[0070] In some embodiments, the ratio of the height of the first support column 141 to the height of the second support column 142 ranges from 0.1 to 0.99. For example, the ratio of the height of the first support column 141 to the height of the second support column 142 may be, but is not limited to, 0.5.

[0071] According to some embodiments of the present application, Figure 8 As shown, the heights of the plurality of first support columns 141 increase in a direction away from the center of the bending region 100. In other words, the first support column 141 at the center of the bending region 100 is the lowest, thereby further improving the bending performance of the vapor chamber, improving the bending reliability, and reducing the curvature radius of the bending.

[0072] In some embodiments, the center of the bending area may be a preset bending axis of the heat sink, and in a direction away from the preset bending axis, the heights of the support columns on both sides of the preset bending axis tend to increase.

[0073] The increasing trend in the heights of the multiple first support columns may mean that in the direction away from the preset bending axis, the heights of the first support columns on both sides of the preset bending axis may, for example, but not limited to, increase successively in an arithmetic progression. It may also mean that in the direction away from the preset bending axis, on both sides of the preset bending axis, the heights of the first support columns at intervals may, for example, but not limited to, increase successively in an arithmetic progression, and the heights of the first support columns within each interval are consistent.

[0074] According to some embodiments of the present application, a thermally conductive film may be provided on at least one surface of the first cover plate, and / or a thermally conductive film may be provided on at least one surface of the second cover plate, and the thermal conductivity of the thermally conductive film is greater than the thermal conductivity of the first cover plate and the thermal conductivity of the second cover plate. Thus, by adding a thermally conductive film on at least one surface of the first cover plate and / or the second cover plate, the thermal conductivity efficiency of the cover plate can be improved, and the thermal conductivity efficiency of the heat spreader can be further improved.

[0075] exist Fig. 9 and Fig.10 In the illustrated example, a first heat-conducting film 15 is disposed on the inner surface of the first cover plate 11 , and a second heat-conducting film 16 is disposed on the inner surface of the second cover plate 12 .

[0076] The thermally conductive film is made of a thermally conductive material, which may be, but is not limited to, made of a metal thermally conductive material, such as Cu, Al, Ag, Mo, etc. The thickness of the thermally conductive film may be 1um to 1000um. The thickness of the thermally conductive film on the first cover plate and the second cover plate may be the same or different. For example, the thickness of the thermally conductive film on the first cover plate may be 10um, and the thickness of the thermally conductive film on the second cover plate may be 20um. In other words, Fig. 9 and Fig.10In the illustrated example, the thickness of the first heat-conducting film 15 may be 10 um, and the thickness of the second heat-conducting film 16 may be 20 um.

[0077] The thermally conductive film can cover the entire surface of the cover, e.g. Fig. 9 and Fig.10 In the illustrated example, the first heat-conducting film 15 and the second heat-conducting film 16 respectively cover the inner surfaces of the first cover plate 11 and the second cover plate 12. The heat-conducting film can also be designed into a specific pattern according to requirements.

[0078] In some embodiments, the thermally conductive film is disposed in the non-bending region, and no thermally conductive film is disposed in the bending region, so as to avoid the problem of the thermally conductive film being easily broken when disposed in the bending region, thereby avoiding the bending performance being affected by the breakage of the thermally conductive film. Fig.11 In the illustrated example, the inner surface and outer surface of the first cover plate 11 are respectively provided with a first heat-conductive film 15 and a third heat-conductive film 17, and the inner surface and outer surface of the second cover plate 12 are respectively provided with a second heat-conductive film 16 and a fourth heat-conductive film 18. The first cover plate 11 can be bent along the preset bending axis in the bending area 100. In this case, only the fourth heat-conductive film 18 can be arranged in the non-bending area, and the fourth heat-conductive film 18 is not arranged in the bending area 100. Since the tensile force caused by the bending on the fourth heat-conductive film 18 is the largest and the most likely to break when bending to the side where the first cover plate 11 is located, the fourth heat-conductive film 18 is not arranged in the bending area 100, so as to reduce the risk of failure of the absorbent core due to breakage. It should be noted that at least one of the first heat-conductive film 15, the second heat-conductive film 16 and the third heat-conductive film 17 can also be arranged in the non-bending area, but not in the bending area, so as to further reduce the risk of failure of the absorbent core due to breakage.

[0079] In some embodiments, Fig.12 As shown, when the two covers of the vapor chamber are sealed by welding and melting technology, the vapor chamber further includes a welding area 300, where the first cover plate and the second cover plate are welded and connected, and the thermal conductive film can be disconnected at the welding area 300 to avoid the welding process affecting the thermal conductive film. Fig.10 In the illustrated example, the first thermally conductive film 15 on the inner surface of the first cover plate 11 is taken as an example to illustrate how the thermally conductive film is disconnected at the welding area 300. As for other thermally conductive films on the first cover plate 11 and the second cover plate 12, their disconnection method at the welding area 300 can be similar to that of the first thermally conductive film 15.

[0080] In some embodiments, Fig.11 and Fig.13As shown, when the first cover plate 11 is arranged close to the heat source 10, the third heat conductive film 17 can also be arranged only in the area of ​​the outer surface of the first cover plate 11 corresponding to the position of the heat source 11, so as to effectively conduct the heat of the heat source 10 to the heat spreader.

[0081] It is understandable that the thermally conductive film may be provided with windows or breaks in other specific areas as required, which are not listed here one by one.

[0082] In some embodiments, when the material of the thermally conductive film is metal, the first cover plate and the second cover plate and the thermally conductive film on their surfaces can be anodized to improve the adhesion between the metal thermally conductive film and the cover plate, thereby improving the thermal conductivity of the cover plate and the bending reliability of the device.

[0083] According to some embodiments of the present application, see Figure 9-11 ,as well as Fig.13 As shown, the inner surface of the second cover plate 12 close to the first cover plate 11 is covered with a second heat-conducting film 16, and the second heat-conducting film 16 includes a body covering the inner surface of the second cover plate and a plurality of protrusions integrally formed with the body, and the protrusions are formed as support columns 14. Thus, the support columns can be integrally formed with the heat-conducting film and formed by the same heat-conducting film through a single photolithography process, which can simplify the manufacturing process.

[0084] It is understandable that the support column can also be prepared by a separate photolithography process, and the prepared support column can be a single-layer structure or a composite structure.

[0085] In the above embodiment, the thermal conductivity of the cover plate is improved by providing a thermally conductive film to enhance the thermal conductivity of the heat spreader. The thermal conductivity of the cover plate may also be improved by other means, for example, by adding thermal through holes on the cover plate to enhance the thermal conductivity of the cover plate, which will be described in detail below in conjunction with specific embodiments.

[0086] According to some embodiments of the present application, see Fig.10 , Fig.11 and Fig.13As shown, a first through hole is provided on the first cover plate 11, and a first heat-conducting plug 19 is filled in the first through hole. The first heat-conducting plug 19 is located in the non-bending area and is staggered with the support column 14, and / or a second through hole is provided on the second cover plate 12, and a second heat-conducting plug 20 is filled in the second through hole. The second heat-conducting plug 20 is located in the non-bending area and is staggered with the support column 14. Thus, by opening a through hole at a position on the cover plate that does not overlap with the projection of the support column and filling it with a thermally conductive material, the contact thermal resistance can be reduced, the thermal conductivity of the cover plate can be improved, and the thermal conductivity efficiency of the heat spreader can be improved. At the same time, the heat-conducting plug does not correspond to the position of the support column, which can avoid affecting the supporting strength of the support column. In addition, the heat-conducting plug is located in the non-bending area, that is, multiple first heat-conducting plugs can be distributed in the non-bending area of ​​the first cover plate, and multiple second heat-conducting plugs can be distributed in the non-bending area of ​​the second cover plate, because the bending area is prone to fracture, which affects the reliability.

[0087] The heat-conducting plug can be made by filling the through hole of the cover plate with a heat-conducting material, and the heat-conducting material can include, but is not limited to, metal powder, metal slurry, etc.

[0088] Multiple heat-conducting plugs can be arranged on the first cover plate and the second cover plate, and the multiple heat-conducting plugs can be evenly distributed on the cover plate. That is, multiple first heat-conducting plugs can be arranged on the first cover plate, and the multiple first heat-conducting plugs can be evenly distributed on the first cover plate. Multiple second heat-conducting plugs can be arranged on the second cover plate, and the multiple second heat-conducting plugs can be evenly distributed on the second cover plate.

[0089] In some embodiments, see Fig.10 , Fig.11 and Fig.13 As shown, a thermally conductive film may be provided on at least one surface of the first cover plate 11, and a plurality of first thermally conductive plugs 19 may be provided on the first cover plate 11, and / or a thermally conductive film may be provided on at least one surface of the second cover plate 12, and a plurality of second thermally conductive plugs 20 may be provided on the second cover plate 12, so as to further improve the thermal conductivity of the cover plate and the heat conduction efficiency. The thermally conductive film and the thermally conductive plugs may be distributed in the non-bending area, that is, the thermally conductive film and the thermally conductive plugs are not provided in the bending area, because the bending area is prone to fracture, which affects the reliability.

[0090] In some embodiments, the third thermally conductive film 17 may be provided only in the area of ​​the outer surface of the first cover plate 11 corresponding to the position of the heat source 10. In this case, the first thermally conductive plug 19 may be provided in the area of ​​the first cover plate 11 corresponding to the position of the heat source 10 to improve the thermal conductivity of the area and effectively conduct the heat generated by the heat source to the heat spreader.

[0091] The structure of the heat spreader and the method for manufacturing the heat spreader of the present application will be described in detail below in conjunction with several exemplary embodiments.

[0092] In a first exemplary embodiment, as Figure 1 As shown, the heat spreader includes a first cover plate 11, a second cover plate 12, a liquid wick 13 and a plurality of support columns 14. The first cover plate 11 and the second cover plate 12 are arranged opposite to each other, and a sealed cavity is formed between the first cover plate 11 and the second cover plate 12. The liquid wick 13 is arranged on the inner surface of the first cover plate 11 close to the second cover plate 12, and a plurality of support columns 14 are arranged on the inner surface of the second cover plate 12 close to the first cover plate 11, and are evenly distributed. The first cover plate 11 and the second cover plate 12 adopt thin glass substrates, which have better airtightness. The liquid wick 13 is a metal wire mesh liquid wick, with warp and weft wires that cross horizontally and vertically, and the angles between the warp and weft wires and the preset bending axis are all 45°. The plurality of support columns 14 are an integral structure with the second cover plate 12 and are made of a thin glass substrate.

[0093] The method for making a vapor chamber may include:

[0094] A Mo metal film with a thickness of more than 500 nm is deposited on the inner surface of a glass substrate with a thickness of 200 μm, and a pattern of a heat-conducting layer is formed by an etching process;

[0095] Then, an anti-etching film is attached to the outer surface of the glass substrate, and the glass substrate is placed in a glass etching solution (mainly composed of HF acid) to etch the glass substrate in the area where the heat conductive layer is not provided, so as to form a plurality of support columns 14, and the glass substrate at the bottom of the support columns forms the second cover plate 12. The heat conductive layer on the support columns can be completely removed or not removed. The height of the support column 14 is 100um, and the thickness of the second cover plate 12 is 100um;

[0096] A liquid absorbent core 13 is arranged on the inner surface of the first cover plate 11. The liquid absorbent core 13 can be selected from metal wire mesh (Cu mesh, Al mesh, stainless steel mesh, etc.), non-metal wire mesh (nylon, spandex, nylon, polyimide, polypropylene, polyethylene, polyester, polyvinyl chloride, polylactic acid, polyhydroxyalkanoic acid, polybutylene succinate, etc.), and the liquid absorbent core can also be a composite liquid absorbent core (for example, a wire mesh liquid absorbent core+groove liquid absorbent core or a sintered metal liquid absorbent core+wire mesh liquid absorbent core), etc., and the liquid absorbent core is subjected to hydrophilization treatment;

[0097] like Fig.14 As shown, the first packaging (i.e. edge packaging) is performed: the edges of the first cover plate and the second cover plate (PI or glass) are bonded together by laser melting technology or adhesive bonding, and a liquid injection hole is left for vacuum injection operation. The mesh structure is a liquid wick.

[0098] like Fig.14As shown, the process flow of packaging and liquid injection includes: first, vacuuming is performed through the vacuum pipe, the vacuum degree reaches 1*10^2Pa, and then liquid injection is performed. The working fluid can be pure water, deionized water, ethanol or ether, etc., and water is generally selected as the working fluid. Then, vacuuming is performed, and the pressure inside the heat spreader is maintained at 10^3Pa, and the exhaust port near the exhaust port section is packaged; then the exhaust pipe is directed upward, the heat spreader is heated, and the non-condensable gas is driven into the upper part for secondary degassing. Secondary packaging is performed at a distance of 0.1mm to 5mm from the liquid wick, and then the excess parts such as the exhaust pipe are cut off outside the secondary packaging, and the preparation of the heat spreader is completed.

[0099] In a second exemplary embodiment, Figure 2 As shown, the heat spreader includes a first cover plate 11, a second cover plate 12, a liquid wick 13 and a plurality of support columns 14. The first cover plate 11 and the second cover plate 12 are arranged opposite to each other, and a sealed cavity is formed between the first cover plate 11 and the second cover plate 12. A first thermally conductive film 15 is arranged on the inner surface of the first cover plate 11 close to the second cover plate 12, and the liquid wick 13 is arranged on the first conductive film 15. A second thermally conductive film 16 is arranged on the inner surface of the second cover plate 12 close to the first cover plate 11, and a plurality of support columns 14 are arranged on the second thermally conductive film 16 and are evenly distributed. The first cover plate 11 and the second cover plate 12 adopt ultra-thin glass substrates or ultra-thin PI, which have better airtightness and bending performance. The thickness of the first cover plate 11 and the second cover plate 12 can be 5um to 100um.

[0100] The method for making a vapor chamber may include:

[0101] 10nm-10um (e.g., 1um) of metal Cu is deposited on the second cover plate 12 by magnetron sputtering, electron beam evaporation, vapor deposition, etc. to improve the thermal conductivity of the device as the second conductive film 16. If the thickness of the second conductive film 16 is greater than 10um, it will cause the temperature to rise after absorbing heat; if the thickness of the second conductive film 16 is less than 10nm, it will cause low heat flux and fail to carry enough heat.

[0102] A photoresist is formed on the second conductive film 16, and a pattern of the photoresist is formed by exposure to form the main body of the support column 14. The thickness of the photoresist is 10 to 120 um;

[0103] Then, an electroplating process is performed to form a heat-conducting layer on the surface of the photoresist, and a support column 14 is formed by the body formed by the photoresist and the heat-conducting layer electroplated on the body. The height of the support column 14 can be, for example, 50 um.

[0104] Sintering the Cu wire mesh liquid wick (e.g., 200 mesh) 13 to the inner surface of the first cover plate 11 to increase adhesion and reduce longitudinal thermal resistance;

[0105] The first cover plate 11 and the second cover plate 12 are assembled to complete the heat spreader. The specific assembly process can refer to the first exemplary embodiment.

[0106] In the third exemplary embodiment, the structure of the heat spreader is the same as that of the second exemplary embodiment, except that the method of anodically bonding the Cu wire mesh wick to the inner surface of the first cover plate improves the adhesion between the first cover plate and the Cu wire mesh wick to improve the reliability of device bending.

[0107] In a fourth exemplary embodiment, as Fig. 9 As shown, the structure of the heat spreader is different from that of the heat spreader in the second exemplary embodiment in that the support column 14 and the second thermally conductive film 16 are integrally formed. And in this exemplary embodiment, the first cover plate 11 and the second cover plate 12 can adopt a flexible substrate, for example, PI, PDMS, PMMA, PE, PET, etc. The thermally conductive films on the first cover plate 11 and the second cover plate 12 can be metal thermally conductive films, for example, Cu, Al, Ag, Mo, etc. The thickness of the flexible substrate can be 1um to 500um, for example, 30um. The thickness of the thermally conductive film can be 1um to 1000um, which can be set as needed. Among them, the thickness of the second thermally conductive film 16 on the second cover plate 12 can be 150um, and the thickness of the first thermally conductive film 15 on the first cover plate 11 can be 10um.

[0108] The steps for making the support column and the second thermally conductive film in the method for making the vapor chamber are different from those in the second exemplary embodiment, and the other steps are the same as those in the second exemplary embodiment. The steps for making the support column and the second thermally conductive film in this exemplary embodiment include:

[0109] A second thermally conductive film 16 with a thickness of 150 um is formed on the second cover plate 12 , and a photolithography process is performed on the second thermally conductive film 16 to form a plurality of protruding structures as support columns 14 ; the thickness of the second thermally conductive film 16 at the bottom of the support column is 20 um.

[0110] In the fifth exemplary embodiment, different from the fourth exemplary embodiment, the first cover plate and the second cover plate adopt ultra-thin glass substrates, and the thermal conductive films in the corresponding welding areas on the first cover plate and the second cover plate are removed, and the welding areas include a first welding area corresponding to the first packaging and a second welding area corresponding to the second packaging, and the thermal conductive films are disconnected in these two welding areas, that is, no conductive film is set in these two welding areas.

[0111] In a sixth exemplary embodiment, as Fig.13 As shown, Fig. 9The fourth exemplary embodiment shown is different in that a third heat-conductive film 17 is provided on the outer surface of the first cover plate 12, the third heat-conductive film 17 is located in the area in contact with the heat source 10, and a first through hole is provided in the area of ​​the first cover plate 11 corresponding to the area in contact with the heat source 10, and the first through hole is filled with a first heat-conductive plug 19.

[0112] Based on the manufacturing method of the fourth exemplary embodiment, the manufacturing method of the vapor chamber in this exemplary embodiment further includes:

[0113] A photoresist may be coated on the outer surface of the first cover plate 11 and exposed to form a photoresist pattern, and the first cover plate without the photoresist region may be etched to form a plurality of first through holes, and the photoresist may be removed;

[0114] Filling the first through hole with Cu powder or metal slurry to form a first heat-conducting plug 19;

[0115] Then, a third heat-conducting film 17 is formed on the outer surface of the first cover plate, and a pattern of the third heat-conducting film 17 is formed by a photolithography process, so that the third heat-conducting film 17 is only located in the area where the heat source is attached.

[0116] In a seventh exemplary embodiment, as Fig.11 As shown, Fig.13 The sixth exemplary embodiment shown is different in that a fourth heat-conducting film 18 is provided on the outer surface of the second cover plate 12, the fourth heat-conducting film 18 is provided in the non-bending area, and the fourth heat-conducting film 18 is not provided in the bending area 100. In addition, a plurality of second through holes are provided on the second cover plate 12, and the second through holes are filled with second heat-conducting plugs 20. The plurality of second heat-conducting plugs 20 can be evenly distributed on the second cover plate. Among them, the manufacturing steps of the fourth heat-conducting film 18, the second through holes and the second heat-conducting plugs 20 can be the same as those of the sixth exemplary embodiment, and will not be described in detail.

[0117] According to some embodiments of the present application, an electronic device is further provided, comprising: a heat source; a heat spreader in the above embodiment, wherein the first cover plate of the heat spreader is arranged close to the heat source. Since the heat spreader in the above embodiment has good bending performance and thermal conductivity, the heat dissipation effect of the electronic device is improved, thereby ensuring the performance of the electronic device.

[0118] In some embodiments, a thermally conductive film may be disposed between the heat source and the first cover plate, that is, a thermally conductive film may be disposed on the outer surface of the first cover plate facing away from the second cover plate. The thermally conductive film may cover the outer surface of the first cover plate, or may be disposed only in the area of ​​the first cover plate that contacts the heat source, thereby improving the heat conduction efficiency and further improving the heat dissipation effect.

[0119] In some embodiments, a first through hole is provided on the first cover plate, and a first heat conducting plug is filled in the first through hole, and the first heat conducting plug corresponds to the position of the heat source. Thus, by providing a through hole at a position corresponding to the heat source on the first cover plate and filling the through hole with the heat conducting plug, the heat conduction efficiency can be further improved.

[0120] Electronic devices can be different types of computer devices, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic devices can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices.

[0121] Although the embodiments or examples of the present disclosure have been described with reference to the accompanying drawings, it should be understood that the above-mentioned methods, systems and devices are merely exemplary embodiments or examples, and the scope of the present invention is not limited by these embodiments or examples, but only by the claims after authorization and their equivalent scope. Various elements in the embodiments or examples can be omitted or replaced by their equivalent elements. In addition, each step can be performed in an order different from that described in the present disclosure. Further, the various elements in the embodiments or examples can be combined in various ways. It is important that with the evolution of technology, many elements described herein can be replaced by equivalent elements that appear after the present disclosure.

Claims

1. A heat sink, characterized in that: include: A first cover plate and a second cover plate are arranged opposite to each other, and a sealed cavity is formed between the first cover plate and the second cover plate; as well as A liquid wick disposed between the first cover plate and the second cover plate, The absorbent core comprises an absorbent mesh, the absorbent mesh comprises warp and weft threads that cross each other horizontally and vertically, the angles between the warp and weft threads and a preset bending axis are both less than 90°, and the heat spreader can be bent along the preset bending axis.

2. The vapor chamber according to claim 1, characterized in that: The heat spreader includes a bending area and a non-bending area, the preset bending axis is located in the bending area, and the heat spreader also includes: A plurality of support columns are disposed between the first cover plate and the second cover plate, one end of each support column abutting against the liquid absorbent core, The multiple support columns include multiple first support columns located in the bending area and multiple second support columns located in the non-bending area. Along the direction parallel to the first cover plate, the number of first support columns per unit area in the bending area is greater than the number of second support columns per unit area in the non-bending area.

3. The heat sink according to claim 2, characterized in that: The cross-sectional area of ​​the first support column is smaller than the cross-sectional area of ​​the second support column.

4. The vapor chamber according to claim 1, characterized in that: The heat spreader includes a bending area and a non-bending area, the preset bending axis is located in the bending area, and the heat spreader also includes: A plurality of support columns are disposed between the first cover plate and the second cover plate, one end of each support column abutting against the liquid absorbent core, The ratio of the density of the support columns in the bending area to the density of the support columns in the non-bending area ranges from 0.01 to 0.99, the density of the support columns in the bending area is the ratio of the sum of the cross-sectional areas of the multiple first support columns to the area of ​​the bending area, and the density of the support columns in the non-bending area is the ratio of the sum of the cross-sectional areas of the multiple second support columns to the area of ​​the non-bending area.

5. The vapor chamber according to claim 4, characterized in that: The ratio of the cross-sectional area of ​​the first support column to the cross-sectional area of ​​the second support column is in the range of 0.25 to 0.

75.

6. The vapor chamber according to claim 2, characterized in that: Along a direction parallel to the first cover plate, the number of first support columns per unit area in the bending region increases by 1% to 500% relative to the number of second support columns per unit area in the non-bending region.

7. The vapor chamber according to claim 2, characterized in that: The height of the first supporting column is smaller than the height of the second supporting column.

8. The vapor chamber according to claim 2, characterized in that: Along the direction away from the center of the bending area, the heights of the plurality of first support pillars increase gradually.

9. The vapor chamber according to any one of claims 2 to 8, characterized in that: At least one surface of the first cover plate is provided with a heat-conducting film. And / or, at least one surface of the second cover plate is provided with a heat-conducting film, and the thermal conductivity of the heat-conducting film is greater than the thermal conductivity of the first cover plate and the thermal conductivity of the second cover plate.

10. The vapor chamber according to claim 9, characterized in that: The thermally conductive film is arranged in the non-bending area.

11. The vapor chamber according to claim 9, characterized in that: The vapor chamber further includes a welding area, the first cover plate and the second cover plate are welded and connected in the welding area, and the thermally conductive film is disconnected at the welding area.

12. The vapor chamber according to claim 9, wherein: The inner surface of the second cover plate close to the first cover plate is covered with the thermally conductive film, and the thermally conductive film includes a body covering the inner surface of the second cover plate and a plurality of protrusions integrally formed with the body, and the protrusions form the support columns.

13. The vapor chamber according to any one of claims 2 to 8, characterized in that: The first cover plate is provided with a first through hole, the first through hole is filled with a first heat-conducting plug, the first heat-conducting plug is located in the non-bending area and is staggered with the support column. And / or, a second through hole is provided on the second cover plate, and a second heat-conducting plug is filled in the second through hole, and the second heat-conducting plug is located in the non-bending area and is staggered with the support column.

14. The vapor chamber according to any one of claims 2 to 8, characterized in that: The first cover plate and the second cover plate are made of glass, and the thickness of the first cover plate and the second cover plate is 5um to 300um.

15. An electronic device, characterized in that: include: Heat source; The heat spreader according to any one of claims 1 to 14, wherein the first cover plate of the heat spreader is arranged close to the heat source.

Images