Ultrathin vapor chamber, preparation method thereof and electronic equipment

Abstract

The invention belongs to the related technical field of phase change heat transfer, and discloses an ultra-thin vapor chamber, a preparation method thereof and electronic equipment, and the ultra-thin vapor chamber is characterized in that a first accommodating groove is formed in one side of an upper cover plate, and a second accommodating groove is formed in one side of a lower cover plate; a plurality of first cylinders are arranged in the first area in an array mode in the first containing groove, and vapor-liquid different-face type liquid absorbing cores are arranged at the positions, corresponding to the first cylinders, in the second containing groove; the interior of the first containing groove and the interior of the second containing groove are respectively provided with supporting column structures which correspond to each other up and down in the second area. A plurality of gap areas are arranged in the supporting column structure, and any gap area is provided with a vapor-liquid coplanar wick. The vapor-liquid different-plane structure and the vapor-liquid coplanar structure are comprehensively utilized, the phase change heat transfer heat resistance is reduced due to the large contact area of the vapor-liquid different planes, the vapor flow resistance of the heat insulation section is reduced due to vapor-liquid coplane, and the heat dissipation capacity of the ultrathin vapor chamber can be improved under the condition that the thickness of the inner cavity is extremely small.

Description

Technical Field

[0001] The present invention belongs to the technical field related to phase change heat transfer, and more specifically, relates to an ultra-thin heat spreader, a preparation method thereof, and an electronic device. Background Art

[0002] Portable electronic devices are developing towards high performance, miniaturization, and integration, which leads to a rapid increase in heat flux density in a small space. The operating temperature of electronic devices has increased significantly, which limits their performance, shortens their service life, increases the probability of electronic device failure, and reduces user satisfaction. Therefore, it is particularly important to achieve efficient heat dissipation in portable electronic devices.

[0003] Ultra-thin vapor chambers, generally referring to vapor chambers with a thickness of less than 2mm, are widely used in portable electronic devices such as smartphones and tablets due to their high heat transfer efficiency and stability. With the development of 5G communication technology and the iteration of electronic devices, the performance of electronic devices has been improved while the thickness of electronic devices has been reduced, resulting in a significant reduction in the installation space of heat dissipation equipment and a significant increase in the performance requirements of heat dissipation equipment. Therefore, the demand for the development of high-performance ultra-thin vapor chambers with a total thickness of less than 0.3mm continues to increase.

[0004] The total thickness of the vapor chamber can be reduced by reducing the thickness of the shell plate, the wick and the steam chamber. However, as the thickness of the vapor chamber and the wick of the vapor chamber decreases, the steam flow resistance in the ultra-thin vapor chamber increases significantly, and the capillary force of the wick decreases, which deteriorates the heat transfer performance of the vapor chamber and makes it difficult to meet the heat dissipation requirements of miniaturized electronic devices.

[0005] Therefore, how to design an ultra-thin vapor chamber with low total thickness and high heat transfer performance has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0006] In view of the above defects or improvement needs of the prior art, the present invention provides an ultra-thin vapor chamber, a preparation method thereof and an electronic device, which are used to solve the problem of poor heat transfer performance of the existing ultra-thin vapor chamber.

[0007] To achieve the above-mentioned object, according to a first aspect of the present invention, there is provided an ultra-thin heat sink, comprising an upper cover plate, a lower cover plate and a working liquid, wherein a first receiving groove is provided on one side of the upper cover plate, and a second receiving groove is provided on one side of the lower cover plate, and the upper cover plate and the lower cover plate are sealedly connected so that the first receiving groove and the second receiving groove are combined to form a sealed cavity, and the sealed cavity is filled with the working liquid;

[0008] The sealed cavity includes a first area and a second area in the length direction, a plurality of first cylinders are arranged in an array in the first area inside the first receiving groove, and a vapor-liquid non-conformal liquid wick is arranged in the second receiving groove at a position corresponding to the first cylinder arrangement area;

[0009] The first receiving tank and the second receiving tank are respectively provided with support column structures in the second area, and the support column structures in the first receiving tank and the support column structures in the second receiving tank correspond to each other up and down; a plurality of gap areas are provided in the support column structures, and the first receiving tank and the second receiving tank are respectively provided with a vapor-liquid coplanar absorbent core in any of the gap areas. .

[0010] According to the ultra-thin heat spreader provided by the present invention, the support column structure includes multiple rows of strip columns along the width direction of the sealed cavity, any row of strip columns is formed by arranging multiple strip columns, and multiple gap areas are arranged between the multiple rows of strip columns.

[0011] According to the ultra-thin heat spreader provided by the present invention, the support column structure includes a plurality of combined column groups along the width direction of the sealed cavity, any of the combined column groups includes at least one row of the strip columns, the gap between two adjacent combined column groups forms the gap region, the widths of the plurality of gap regions are the same, and when the combined column group includes a plurality of rows of the strip columns, the spacing between two adjacent rows of the strip columns is the same;

[0012] And / or, the ratio of the total width of the plurality of gap regions to the width of the sealed cavity is 40-60%; and the number of the gap regions is 3-5.

[0013] According to the ultra-thin vapor chamber provided by the present invention, when the combined column group includes multiple rows of the strip columns, two adjacent rows of the strip columns are staggered;

[0014] And / or, the two combined column groups located on both sides of the support column structure in the width direction respectively include a row of the strip columns.

[0015] According to the ultra-thin heat spreader provided by the present invention, the second region is located in the middle of the sealed cavity along the length direction, and regions on both sides of the second region along the length direction are respectively set as the first regions.

[0016] According to the ultra-thin vapor chamber provided by the present invention, the vapor-liquid coplanar wick disposed in any of the gap regions inside the second containing tank is a microcolumn array.

[0017] According to a second aspect of the present invention, a method for preparing an ultra-thin vapor chamber is provided, which is used to prepare the ultra-thin vapor chamber described in any one of the above items, wherein the vapor-liquid coplanar wick disposed in any of the gap regions inside the second receiving tank in the ultra-thin vapor chamber is a microcolumn array, and the preparation method comprises:

[0018] The first receiving groove, the first column and the supporting column structure are prepared by etching on the upper cover plate, and the second receiving groove, the micro-column array and the supporting column structure are prepared by etching on the lower cover plate;

[0019] After etching the column structure, the lower cover plate and the wick material are cleaned respectively, wherein the wick material includes a vapor-liquid skew-type wick and a vapor-liquid coplanar wick;

[0020] Sintering the cleaned wick material on the cleaned lower cover plate, wherein the vapor-liquid skew-type wick is sintered on the inner wall of the lower cover plate, and the vapor-liquid coplanar wick is sintered on the microcolumn array;

[0021] The lower cover plate after sintering the liquid wick material is cleaned again, and then a micro-nano structure is prepared on the liquid wick material by etching, and then a washing operation is performed with water;

[0022] The upper cover plate and the lower cover plate are sealed and connected to form a shell, and an injection pipe is connected to one end of the shell. Then, the working liquid is injected into the shell through the injection pipe, and a sealing operation is performed to obtain the ultra-thin heat spreader.

[0023] According to the method for preparing an ultra-thin vapor chamber provided by the present invention, after preparing the micro-nano structure and before sealingly connecting the upper cover plate and the lower cover plate, the method further comprises:

[0024] The upper cover plate after etching the pillar structure and the lower cover plate after preparing the micro-nano structure are respectively pickled.

[0025] According to the method for preparing the ultra-thin vapor chamber provided by the present invention, injecting the working liquid into the shell and performing a sealing operation specifically includes:

[0026] Allow pure water to continue boiling for a preset time or longer as the working liquid, and then inject the working liquid into the sealed cavity;

[0027] The shell after the working liquid is injected is immersed in liquid nitrogen, and the sealed cavity is evacuated, and then the injection pipe is closed with a pressure clamp to complete a degassing operation;

[0028] After the first degassing, the shell is immersed in boiling water for a preset time, and then the second degassing is performed, and then the injection tube is sealed for a second time to complete the sealing of the injection tube.

[0029] According to a third aspect of the present invention, there is provided an electronic device, comprising any one of the above-mentioned ultra-thin vapor chambers, and also comprising a working module, wherein the ultra-thin vapor chamber is used to dissipate heat for the working module.

[0030] In general, compared with the prior art, the above technical solutions conceived by the present invention provide an ultra-thin vapor chamber, a preparation method thereof, and an electronic device:

[0031] 1. A first cylinder and a support column structure are arranged inside the sealed cavity to provide support and form a steam flow channel. The wick is used to condense the liquid working medium and is a flow channel for the liquid working medium. The gap on the wick can provide capillary force to promote the flow of the liquid working medium. The vapor-liquid skewness structure and the vapor-liquid coplanar structure are used comprehensively. The larger contact area of ​​the vapor-liquid skewness type wick reduces the phase change heat transfer thermal resistance. The vapor-liquid coplanar wick reduces the steam flow resistance of the insulation section and reduces the steam heat transfer thermal resistance, which is beneficial to improve the heat dissipation capacity of the ultra-thin heat spreader under the condition of extremely small inner cavity thickness, thereby further reducing the thickness of the heat spreader, improving the heat transfer performance of the ultra-thin heat spreader, and meeting the heat dissipation requirements of highly integrated ultra-thin electronic devices.

[0032] 2. The support column structure is set as a strip column structure, which is conducive to improving the support strength inside the sealed cavity while ensuring smooth steam flow and reducing steam flow resistance, thereby facilitating the overall structural stability of the vapor chamber and ensuring the normal use of the vapor chamber;

[0033] 3. The vapor-liquid coplanar wick arranged in any gap area inside the second receiving tank is set as a microcolumn array. By designing the size of the second cylinder constituting the microcolumn array, the second cylinder is also set as a vapor-liquid coplanar structure, which is beneficial to improve the support strength and ensure the smaller flow resistance and heat transfer resistance of the steam, thereby improving the heat exchange performance of the heat exchange plate;

[0034] 4. The thickness of the ultra-thin vapor chamber provided can be reduced to 0.25mm, which is much lower than the traditional ultra-thin vapor chamber with different vapor and liquid surfaces. By combining the vapor-liquid different-surface wick and the vapor-liquid coplanar wick, the effective thermal conductivity can reach 6000~24000W / (m·K) at extreme thickness. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of the upper cover plate provided by the present invention;

[0036] Figure 2 It is a structural schematic diagram of a lower cover plate without a liquid absorbent core provided by the present invention;

[0037] Figure 3 It is a schematic diagram of the entity of the upper cover plate provided by the present invention;

[0038] Figure 4 It is a schematic diagram of the entity of the lower cover plate provided by the present invention before sintering to prepare the liquid wick;

[0039] Figure 5 It is a schematic diagram of the entity of the lower cover plate provided by the present invention after sintering to prepare the liquid wick;

[0040] Figure 6 It is a schematic diagram of the specific dimensions of the support column structure provided by the present invention;

[0041] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0042] 1-upper cover; 11-first receiving groove; 12-first cylindrical column; 13-strip column; 14-gap area; 21-first area; 22-second area; 3-lower cover; 31-second receiving groove; 32-micro-column array; 33-vapor-liquid non-planar wick; 34-vapor-liquid co-planar wick; 4-punch area. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0044] See also Figure 1 and Figure 2 , the first embodiment provides an ultra-thin heat sink, which includes an upper cover plate 1, a lower cover plate 3 and a working liquid, a first receiving groove 11 is provided on one side of the upper cover plate 1, a second receiving groove 31 is provided on one side of the lower cover plate 3, the upper cover plate 1 and the lower cover plate 3 are sealed and connected so that the first receiving groove 11 and the second receiving groove 31 are combined to form a sealed cavity, and the sealed cavity is filled with the working liquid;

[0045] The sealed cavity includes a first area 21 and a second area 22 in the length direction. A plurality of first cylinders 12 are arranged in an array in the first area 21 inside the first receiving groove 11. A vapor-liquid eccentric liquid wick 33 is arranged inside the second receiving groove 31 at a position corresponding to the area where the first cylinder 12 is arranged.

[0046] The first receiving tank 11 and the second receiving tank 31 are provided with support column structures in the second area 22, and the support column structures in the first receiving tank 11 and the support column structures in the second receiving tank 31 correspond to each other up and down; a plurality of gap areas 14 are provided in the support column structures, and a vapor-liquid coplanar absorbent core is provided in any of the gap areas 14 in the first receiving tank 11 and the second receiving tank 31. The support column structure in the first receiving tank 11 is provided with a plurality of gap areas 14, and the support column structure in the second receiving tank 31 is also provided with a plurality of gap areas 14, and the gap areas 14 in the first receiving tank 11 and the gap areas 14 in the second receiving tank 31 correspond to each other up and down.

[0047] During the use of the heat spreader, the lower cover plate 3 can contact the heat source, and the initial sealed cavity is filled with liquid working fluid. The working fluid can be adsorbed in the liquid wicks including the skew type and the coplanar type. After heating, the working fluid evaporates into steam, and the steam formed in the vapor-liquid skew type liquid wick 33 flows upward to the first cylinder 12 area, flows in the gap of the first cylinder 12 and flows along the gap of the support column structure; the liquid medium in the vapor-liquid skew type liquid wick 33 is reduced, so that the liquid medium in the vapor-liquid coplanar type liquid wick 34 will flow to the vapor-liquid skew type liquid wick 33; thereby, the heat dissipation of the heat source is achieved through the flow of the medium.

[0048] The first cylinder 12 and the support column structure can play a supporting role inside the sealed cavity to improve the structural stability of the heat spreader. The heat spreader is provided with a vapor-liquid non-planar wick 33 to reduce the phase change heat transfer thermal resistance by utilizing its large heat exchange area. The vapor-liquid coplanar wick 34 is also provided in the multiple gap areas 14 formed by the support column structure in the second area to reduce the steam flow resistance in the insulation section and reduce the steam heat transfer thermal resistance. The combined use of the two improves the heat transfer capacity of the ultra-thin heat spreader, and can reduce the thickness of the heat spreader while improving the heat transfer capacity.

[0049] Further, the vapor-liquid coplanar wick 34 disposed in any of the gap regions 14 inside the second receiving groove 31 is a microcolumn array 32. The microcolumn array 32 is formed by arranging a second cylindrical array, the diameter of the first cylindrical array 12 is greater than the diameter of the second cylindrical array, and a plurality of the second cylindrical arrays disposed in any of the gap regions 14 also form a vapor-liquid coplanar structure. Figure 2In this embodiment, the size of the second cylinder is designed to be smaller, and a plurality of the second cylinders arranged in an array in any gap region 14 form a microcolumn array 32. The gaps between the microcolumn arrays 32 are smaller, and can provide capillary force to promote the flow of liquid working fluid, so that the microcolumn array 32 is used for the flow of liquid working fluid, and the support column structure located in the same plane as the microcolumn array 32 is used for steam flow. The microcolumn array 32 forms a vapor-liquid coplanar structure, that is, the microcolumn array 32 also serves as a vapor-liquid coplanar liquid wick 34, which is beneficial to reducing the steam flow resistance and improving the heat transfer capacity.

[0050] In some specific embodiments, reference Figure 1 and Figure 2 The support column structure includes multiple rows of strip columns 13 along the width direction of the sealed cavity, and any row of strip columns 13 is formed by arranging multiple strip columns 13, and multiple gap areas 14 are arranged between the multiple rows of strip columns 13. The strip columns 13 are long columns in the length direction.

[0051] Specifically, the support column structure includes a plurality of combined column groups along the width direction of the sealing cavity, any of the combined column groups includes at least one row of the strip columns 13, the gap between two adjacent combined column groups forms the gap area 14, the widths of the plurality of gap areas 14 are the same, and when the combined column group includes multiple rows of the strip columns 13, the spacing between two adjacent rows of the strip columns 13 is the same.

[0052] Specifically, the total width of the plurality of gap regions 14 is 40-60% of the width of the sealed cavity; the number of the gap regions 14 is 3-5. The vapor-liquid coplanar structure formed under this design parameter can better facilitate the flow of steam, reduce the steam flow resistance of the insulation section, reduce the steam heat transfer resistance, and ensure that the support column structure can stably support the cavity.

[0053] refer to Figure 1 and Figure 2 When the combined column group includes multiple rows of the strip columns 13, two adjacent rows of the strip columns 13 are staggered; this is beneficial to ensure the smooth flow of steam in the gaps between the strip columns 13 and avoid the occurrence of flow dead corners.

[0054] The two combined column groups located on both sides of the support column structure in the width direction respectively include a row of strip columns 13. A row of strip columns 13 is arranged on each side, and a gap area 14 is arranged adjacent to the row of strip columns 13. This arrangement is conducive to ensuring the support strength of the support column structure at the edge part, and making the support column structure as close to the middle part as possible, which is conducive to the smooth flow of steam and improves the heat exchange capacity.

[0055] refer to Figure 1 and Figure 2 In this embodiment, the second area 22 is located in the middle of the sealed cavity along the length direction, and the areas on both sides of the second area 22 along the length direction are respectively set as the first area 21. The first area 21 on one side is a heat exchange evaporation section, the second area 22 in the middle is an insulation section, and the first area 21 on the other side is a condensation section, which can better realize the circulation of the medium to achieve heat dissipation from the heat source.

[0056] During the specific use of the heat spreader, the evaporation side of the lower cover plate 3 can contact the heat source, and the initial sealed cavity is filled with liquid working fluid, which can be adsorbed in the liquid wick. The working fluid on the evaporation side is heated and evaporated into steam. Under the action of the pressure difference, it flows through the first cylinder 12 on the evaporation side, the support column structure, and the first cylinder 12 on the condensation side in sequence, and condenses into liquid in the condensation section. The liquid working medium is adsorbed by the liquid wick on the condensation side and then refluxed from the liquid wick to the liquid wicks in the insulation section and the evaporation section, and the cycle works. The heat spreader uses the phase change and flow of the working fluid to achieve heat dissipation from the heat source.

[0057] Furthermore, the vapor-liquid skew type wick 33 and the vapor-liquid coplanar wick 34 are provided with micro-nano structures respectively. The vapor-liquid skew type wick 33 can be sintered on the inner wall of the lower cover plate 3; the vapor-liquid coplanar wick 34 can be sintered on the second cylindrical array. The vapor-liquid skew type wick 33 and the vapor-liquid coplanar wick 34 arranged in any gap area 14 inside the first receiving tank 11 can be copper meshes respectively. That is, the microcolumn, i.e., the second cylinder, and the copper mesh can be connected by sintering to form a vapor-liquid coplanar wick, and the copper mesh of the vapor-liquid skew type wick can also be connected to the lower cover plate 3.

[0058] In some specific embodiments, the depth ratio of the first accommodating groove 11 and the second accommodating groove 31 is 1:2-2:1. The diameter of the first cylinder 12 is 0.6-1mm, and the distance between the centers of two adjacent first cylinders 12 is 0.6-3mm. The diameter of the second cylinder is 0.08-0.12mm, and the distance between the centers of two adjacent second cylinders is 0.2-0.4mm. The width of the strip column 13 in the width direction is 0.2-0.6mm; the length of the strip column 13 in the length direction is 1.2-7mm; the spacing between two adjacent rows of strip columns 13 in the combined column group is 1-2mm; the spacing between two adjacent strip columns 13 in the same row of strip columns 13 is 0.4-1.2mm, such as Figure 6 The heat spreader formed by the above-mentioned design dimensions has good supporting strength and good heat exchange performance.

[0059] The second embodiment provides a method for preparing an ultra-thin vapor chamber, which is used to prepare the ultra-thin vapor chamber described in any of the above items, wherein the vapor-liquid coplanar wick disposed in any of the gap regions inside the second receiving tank in the ultra-thin vapor chamber is a microcolumn array, and the preparation method comprises:

[0060] The first receiving groove 11, the first column 12 and the supporting column structure are prepared by etching on the upper cover plate 1, and the second receiving groove 31, the micro-column array 32 and the supporting column structure are prepared by etching on the lower cover plate 3. Figure 3 and Figure 4 As shown;

[0061] After etching the column structure, the lower cover plate 3 and the wick material are cleaned respectively, wherein the wick material includes a vapor-liquid skew-type wick 33 and a vapor-liquid coplanar wick 34;

[0062] The cleaned wick material is sintered on the cleaned lower cover plate 3, wherein the vapor-liquid skew-type wick 33 is sintered on the inner wall of the lower cover plate 3, and the vapor-liquid coplanar wick 34 is sintered on the microcolumn array 32. Figure 5 As shown;

[0063] The lower cover plate 3 after sintering the liquid wick material is cleaned again, and then a micro-nano structure is prepared on the liquid wick material by etching, and then rinsed with water;

[0064] The upper cover plate 1 and the lower cover plate 3 are sealed and connected to form a shell, and an injection pipe is connected to one end of the shell. Then, the working liquid is injected into the shell through the injection pipe, and a sealing operation is performed to obtain the ultra-thin heat spreader.

[0065] Further, the first receiving groove 11, the first column 12 and the supporting column structure are prepared by etching on the upper cover plate 1, and the second receiving groove 31, the micro-column array 32 and the supporting column structure are prepared by etching on the lower cover plate 3, that is, after etching the column structures on the upper cover plate 1 and the lower cover plate 3 respectively, the method further includes:

[0066] A punching operation is performed on one end of the upper cover plate 1 and one end of the lower cover plate 3 to obtain a punching area 4, and a certain shape is formed in the punching area 4. After punching, there are two openings of different sizes on the surface of the shell plate, that is, the punching area 4 at the end of the upper cover plate 1 is connected to the first receiving groove 11, and the punching area 4 at the end of the lower cover plate 3 is connected to the second receiving groove 31, which is used for subsequent connection of the injection pipe and formation of the injection channel.

[0067] Furthermore, after preparing the micro-nano structure and before sealing and connecting the upper cover plate 1 and the lower cover plate 3, the method further includes:

[0068] The upper cover plate 1 after etching the pillar structure and the lower cover plate 3 after preparing the micro-nano structure are respectively pickled.

[0069] Furthermore, injecting the working fluid into the shell and performing a sealing operation specifically includes:

[0070] Allow pure water to continue boiling for a preset time or longer as the working liquid, and then inject the working liquid into the sealed cavity;

[0071] The shell after the working liquid is injected is immersed in liquid nitrogen, and the sealed cavity is evacuated, and then the injection pipe is closed with a pressure clamp to complete a degassing operation;

[0072] After the first degassing, the shell is immersed in boiling water for a preset time, and then the second degassing is performed. Then, the injection tube is sealed for a second time to complete the sealing of the injection tube, that is, the sealing operation is completed.

[0073] The third embodiment provides an electronic device, which includes the ultra-thin vapor chamber described in any one of the above items, and also includes a working module, wherein the ultra-thin vapor chamber is used to dissipate heat from the working module. The electronic device may be a mobile phone, a tablet, or other device that requires a heat dissipation module, and the heat dissipation module includes the ultra-thin vapor chamber.

[0074] The core of this embodiment is to provide an ultra-thin heat spreader with a total thickness of less than 0.3 mm and excellent heat transfer performance, which can meet the heat dissipation requirements of high-performance miniaturized electronic devices. Figure 1-Figure 6 As shown, the ultra-thin heat spreader includes an upper cover plate 1, a lower cover plate 3, and a working fluid. The upper cover plate 1 and the lower cover plate 3 are sealed together to form a cavity, and the cavity contains the working fluid. The upper cover plate 1 includes an upper shell plate, a support column structure, and a first cylinder 12. The lower cover plate 3 includes a lower shell plate, a support column structure, and a liquid wick. The support column structure and the first cylinder 12 provide support and a vapor flow channel. The liquid wick includes a vapor-liquid skew-type liquid wick 33, and a vapor-liquid coplanar structure formed by a vapor-liquid coplanar liquid wick 34 and a microcolumn array 32. The vapor-liquid skew-type liquid wick 33 is a copper mesh, and the vapor-liquid coplanar structure is a combination of a copper mesh and microcolumns.

[0075] The specific preparation steps are as follows: etching the copper plate made of C19400, the etching depth of the copper plate with a thickness of 0.1mm is 0.05mm, and the upper shell plate, the support column structure, and the first cylinder 12 are obtained; the etching depth of the copper plate with a thickness of 0.15mm is 0.1mm, and the lower shell plate, the support column structure, and the micro-column array 32, i.e., the second cylinder, are obtained. The diameter of the first cylinder 12 is 0.6mm, and the distance between the centers of adjacent first cylinders 12 is 1.2mm; the diameter of the micro-column, i.e., the second cylinder, is 0.1mm, and the distance between the centers of adjacent micro-columns is 0.325mm; the width of the strip column 13 is 0.4mm, and the row spacing between two adjacent rows of strip columns 13 in the same combined column group is 1.2mm, and the distance between adjacent strip columns 13 in the same row is 0.6mm.

[0076] The copper mesh and the lower cover plate 3 without the copper mesh are cleaned with ethyl acetate, anhydrous ethanol, a 5% dilute sulfuric acid solution, and deionized water in turn, and blown dry after cleaning. The cleaning operation can preferably be carried out by ultrasonic cleaning. The copper mesh and the lower cover plate 3 without the copper mesh are clamped with a graphite mold, placed in the quartz pipe of the vacuum sintering furnace, and high-temperature composite sintering is performed by gradient heating. First, heat to 40°C at a rate of 2°C / min as a preheating stage, and then spend 55 minutes to raise the temperature from 40°C to 300°C, and then heat to 600°C at a rate of 300°C / h, and keep warm for 90 minutes.

[0077] A micro-nano structure for promoting the reflux of liquid working fluid is etched on the liquid wick. After the 3D copper wire is vacuum sintered on the lower cover plate 3 to form a composite structure, the sintered lower cover plate 3 is cleaned with ethyl acetate, anhydrous ethanol, a 5% dilute sulfuric acid solution, and deionized water in sequence. The cleaning operation can be specifically carried out by cleaning with ethyl acetate and ethanol, and then soaking in a 5% dilute sulfuric acid solution to remove surface grease and oxides and other pollutants, and then rinsing with pure water and drying; after drying, it is placed in an alkaline etching solution and the etching process is completed in a water bath heating environment. After the etching is completed, the surface is immediately rinsed with a large amount of pure water.

[0078] The upper and lower cover plates are pickled, ultrasonically cleaned in 5% by mass dilute sulfuric acid, and then cleaned with deionized water and anhydrous ethanol, so that the surface structural component is Cu.

[0079] After the upper and lower covers are aligned and fixed, welding is performed according to a set path to obtain an ultra-thin heat spreader shell that is sealed on all sides and only retains the notch area 4. Then, a liquid injection pipe is installed in the notch area 4 by high-frequency welding to obtain the ultra-thin heat spreader body.

[0080] The preparation method of double degassing is adopted. Pure water is boiled continuously for more than two hours. Then a certain amount of working liquid is injected into the ultra-thin heat spreader shell with a precision syringe. After the injection is completed, the shell injection tube, which can be a copper tube, is connected to the external pipe of the molecular pump group. The shell is immersed in liquid nitrogen. The vacuum pump and molecular pump are turned on in turn. When the molecular pump group pressure display is 1×10 - 3 When the pressure is below hPa, the copper tube is sealed with a pressure clamp to complete the primary degassing. Then the shell heating section is immersed in 100℃ water for 90s for secondary degassing, and then a secondary seal is performed 1cm below the primary seal position to isolate the non-condensable gas. The shell is then sealed with resistance welding.

[0081] This embodiment has the following advantages: the first cylinder 12 and the support column structure are used to provide support and form a vapor flow channel, the wick is used to condense the liquid working medium, and is the flow channel of the liquid working medium, wherein the gaps in the copper mesh, the gaps between the micro-columns, and the micro-nanostructures on the surface of the wick can provide capillary force to promote the flow of the liquid working medium. The larger contact area of ​​the vapor-liquid non-planar wick 33 reduces the phase change heat transfer thermal resistance, and the vapor-liquid coplanar wick 34 reduces the vapor flow resistance of the insulation section, reduces the vapor heat transfer thermal resistance, and improves the heat dissipation capacity of the ultra-thin heat spreader under extremely small inner cavity thickness conditions. The total thickness is only 0.25 mm, and it has excellent heat transfer performance, so it can meet the heat dissipation requirements of high-performance miniaturized electronic equipment.

[0082] The wick after etching and pickling has excellent hydrophilicity. The gaps in the copper mesh, the gaps between the micro-pillars, and the micro-nano structures on the surface of the wick can provide capillary force to promote the flow of liquid working fluid. The total thickness of the ultra-thin heat spreader of this embodiment is only 0.25 mm, which is much lower than the traditional ultra-thin heat spreader of vapor-liquid skewness. The vapor-liquid skewness type wick 33 and the vapor-liquid coplanar wick 34 are combined. The working fluid used is water. At an extreme thickness of 0.25 mm, the effective thermal conductivity of 6000 to 24000 W / (m·K) can be maintained.

[0083] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An ultra-thin heat spreader, characterized in that: The invention comprises an upper cover plate, a lower cover plate and a working fluid, wherein a first receiving groove is provided on one side of the upper cover plate, a second receiving groove is provided on one side of the lower cover plate, the upper cover plate and the lower cover plate are sealedly connected so that the first receiving groove and the second receiving groove are combined to form a sealed cavity, and the sealed cavity is filled with the working fluid; The sealed cavity includes a first area and a second area in the length direction, a plurality of first cylinders are arranged in an array in the first area inside the first receiving groove, and a vapor-liquid non-conformal liquid wick is arranged in the second receiving groove at a position corresponding to the first cylinder arrangement area; The interior of the first receiving groove and the interior of the second receiving groove are respectively provided with support column structures in the second area, and the support column structure inside the first receiving groove and the support column structure inside the second receiving groove correspond to each other up and down; a plurality of gap areas are arranged in the support column structures, and the interior of the first receiving groove and the interior of the second receiving groove are respectively provided with a vapor-liquid coplanar liquid absorbent core in any of the gap areas.

2. The ultra-thin vapor chamber according to claim 1, characterized in that: The support column structure includes a plurality of rows of strip columns along the width direction of the sealing cavity, any row of strip columns is formed by arranging a plurality of strip columns, and a plurality of gap areas are arranged between the rows of strip columns.

3. The ultra-thin vapor chamber according to claim 2, wherein: The support column structure includes a plurality of combined column groups along the width direction of the sealed cavity, any of the combined column groups includes at least one row of the strip columns, the gap between two adjacent combined column groups forms the gap region, the widths of the plurality of gap regions are the same, and when the combined column group includes a plurality of rows of the strip columns, the spacing between two adjacent rows of the strip columns is the same; And / or, the ratio of the total width of the plurality of gap regions to the width of the sealed cavity is 40-60%; and the number of the gap regions is 3-5.

4. The ultra-thin vapor chamber according to claim 3, characterized in that: When the combined column group includes multiple rows of strip columns, two adjacent rows of strip columns are arranged in a staggered manner; And / or, the two combined column groups located on both sides of the support column structure in the width direction respectively include a row of the strip columns.

5. The ultra-thin vapor chamber according to any one of claims 1 to 4, characterized in that: The second area is located in the middle of the sealed cavity along the length direction, and areas on both sides of the second area along the length direction are respectively set as the first areas.

6. The ultra-thin vapor chamber according to any one of claims 1 to 4, characterized in that: The vapor-liquid coplanar wick disposed in any of the gap regions inside the second containing tank is a microcolumn array.

7. A method for preparing an ultra-thin vapor chamber, characterized in that: For preparing the ultra-thin vapor chamber according to any one of claims 1 to 6, the vapor-liquid coplanar wick provided in any of the gap regions inside the second containing tank in the ultra-thin vapor chamber is a microcolumn array, and the preparation method comprises: Etching the first receiving groove, the first column and the supporting column structure on the upper cover plate, and etching the second receiving groove, the micro-column array and the supporting column structure on the lower cover plate; After etching the column structure, the lower cover plate and the wick material are cleaned respectively, wherein the wick material includes a vapor-liquid skew-type wick and a vapor-liquid coplanar wick; Sintering the cleaned wick material on the cleaned lower cover plate, wherein the vapor-liquid skew-type wick is sintered on the inner wall of the lower cover plate, and the vapor-liquid coplanar wick is sintered on the microcolumn array; The lower cover plate after sintering the liquid wick material is cleaned again, and then a micro-nano structure is prepared on the liquid wick material by etching, and then a washing operation is performed with water; The upper cover plate and the lower cover plate are sealed and connected to form a shell, and an injection pipe is connected to one end of the shell. Then, the working liquid is injected into the shell through the injection pipe, and a sealing operation is performed to obtain the ultra-thin heat spreader.

8. The method for preparing an ultra-thin vapor chamber according to claim 7, wherein: After preparing the micro-nano structure and before sealing and connecting the upper cover plate and the lower cover plate, the method further includes: The upper cover plate after etching the pillar structure and the lower cover plate after preparing the micro-nano structure are respectively pickled.

9. The method for preparing an ultra-thin vapor chamber according to claim 7, wherein: Injecting the working fluid into the shell and performing a sealing operation specifically includes: Allow pure water to continue boiling for a preset time or longer as the working liquid, and then inject the working liquid into the sealed cavity; The shell after the working liquid is injected is immersed in liquid nitrogen, and the sealed cavity is evacuated, and then the injection pipe is closed with a pressure clamp to complete a degassing operation; After the first degassing, the shell is immersed in boiling water for a preset time, and then the second degassing is performed, and then the injection tube is sealed for a second time to complete the sealing of the injection tube.

10. An electronic device, characterized in that: The ultra-thin heat spreader comprises any one of claims 1 to 6, and further comprises a working module, wherein the ultra-thin heat spreader is used to dissipate heat for the working module.

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