CN111043886B

CN111043886B - Method for manufacturing ultrathin hot tube plate with printed capillary structure

Info

Publication number: CN111043886B
Application number: CN201811187450.0A
Authority: CN
Inventors: 陈振贤
Original assignee: Guangzhou Lihe Thermal Management Technology Co ltd
Current assignee: Guangzhou Lihe Thermal Management Technology Co ltd
Priority date: 2018-10-12
Filing date: 2018-10-12
Publication date: 2021-05-25
Anticipated expiration: 2038-10-12
Also published as: CN111043886A; WO2020073905A1

Abstract

A method of making an ultra-thin hot tube sheet with printed capillary structures, comprising the steps of: providing a first sheet structure and a second sheet structure; forming a first groove on the first sheet structure; printing a sizing agent on an inner surface of the first groove; heating the first sheet structure to form a capillary structure on the inner surface of the slurry; pressing and sealing the first sheet-shaped structure and the second sheet-shaped structure to form an inner cavity between the first groove capillary structure and the second sheet-shaped structure; and processing the sealing device of the first sheet structure and the second sheet structure to form an ultrathin hot tube plate with a heat conduction function. Therefore, the capillary structure manufactured by the method disclosed by the invention is convenient to operate and beneficial to mass production, and can be applied to manufacturing heat conduction elements in miniaturized electronic products such as intelligent mobile phones and the like.

Description

Method for manufacturing ultrathin hot tube plate with printed capillary structure

Technical Field

The invention provides a method for manufacturing an ultrathin heat pipe plate with a printing capillary structure, in particular to a method for manufacturing an ultrathin heat pipe plate by printing a slurry and heating the slurry to form a porous capillary structure.

Background

The development trend of electronic and handheld communication devices is continuously towards thinning and high functionality, and demands on the operation speed and functions of a Microprocessor (Microprocessor) in the device are also increasing. The microprocessor is a core component of electronic and communication products, and is easy to generate heat under high-speed operation to become a main heating element of an electronic device, and if the heat cannot be dissipated instantly, a local processing Hot Spot (Hot Spot) is generated. Without a good thermal management scheme and a heat dissipation system, the microprocessor is often overheated and cannot perform its intended function, which may even affect the lifetime and reliability of the whole electronic device system. Therefore, electronic products need excellent heat dissipation capability, and particularly, ultra-thin electronic devices such as smart phones (smartphones) and Tablet PCs (Tablet PCs) need excellent heat dissipation capability. The Heat dissipation and Heat dissipation of the electronic and communication products is realized by contacting one surface of a flat Micro Heat Pipe (Micro Heat Pipe) or a Vapor Chamber (Vapor Chamber) with a Heat source and the other surface with a chassis of the electronic device.

The micro-heat pipe or the temperature-equalizing plate is basically a closed cavity containing working fluid, and the purpose of rapid heat conduction or heat dissipation is achieved by means of the liquid-gas two-phase change of the continuous circulation of the working fluid in the cavity and the gas-liquid return convection between the heat absorption end and the condensation end of gas and liquid. Generally, the micro heat pipe is in a long cylindrical shape, and the larger the inner cavity space is, the faster the convection speed is, and the better the heat conduction and the heat dissipation are. However, in order to meet the requirement of thinning electronic products, the current technology needs to process the heat pipe into a flat and long shape to be disposed in a space with a narrow height in the casing, and even needs to use an ultra-thin micro heat pipe with a thickness less than 0.5 mm.

At present, smart mobile phones with a thickness of less than 5mm are already on the market. The thickness of the back cover of the mobile phone is usually less than 1.0mm, and the space for plugging the flat micro heat pipe is only left between 0.3mm and 0.4mm from the surface of the microprocessor on the circuit board and the inner surface of the back cover of the mobile phone. If the ultra-thin micro-heating conduit is manufactured by flattening a copper pipe with the pipe diameter of 2mm, the height of the cavity of the flat micro-heating conduit can be only about 0.2mm by deducting the thickness of the upper wall and the lower wall, and the internal space of the air passage is often very narrow by deducting the thickness of the capillary structure. Such a small convective vapor gas channel greatly limits the heat-releasing and dissipating effects of the micro-thermal conduit, and further cannot cope with the increasing heat-dissipating function of the microprocessor.

In addition, a heat pipe plate is manufactured by laying fiber (fiber) or woven copper mesh (mesh) in a heat pipe plate formed by laminating two grooved copper sheets to form a capillary structure for guiding a working fluid. However, the porosity of the fiber or the woven copper mesh is low and the capillary force is poor, which leads to poor heat-clearing and heat-conducting efficiency, and the capillary structure of the fiber or the woven copper mesh laid and formed in the groove structure with the depth of only 100-200 um on a flat plate is often manufactured with the help of a jig by manpower, so that the automatic production difficulty is high and the yield is low. In the face of the supply chain nature of the smartphone application market, electronic component providers are generally required to mass produce and supply in short periods of time. Therefore, the method of laying fiber or woven copper mesh to make capillary structure has become the bottleneck process of mass production of ultra-thin heat pipe plate.

Disclosure of Invention

In view of the above, the present invention provides a method for manufacturing an ultra-thin heat pipe plate with a printed capillary structure, which is different from the conventional method of laying fibers or weaving copper mesh, printing a slurry in the grooves of a sheet structure, reheating the slurry to form a porous capillary structure, and then manufacturing the ultra-thin heat pipe plate. Therefore, the capillary force of the formed capillary structure is better, the inner cavity of the air passage has more flexible design space, and the air passage is easier to manufacture into a thinner heat pipe plate. Because the printing mode is adopted for manufacturing, the automation of mass production of products is greatly improved, and the degree of production cost is reduced.

In order to achieve the above object, the present invention discloses a method for manufacturing an ultra-thin heat pipe plate having a printed capillary structure, characterized by comprising the steps of:

providing a first sheet structure and a second sheet structure;

forming a first groove on the first sheet structure;

printing a slurry on an inner surface of the first groove;

heating the first sheet structure to form a capillary structure on the inner surface of the slurry;

pressing and sealing the first sheet structure and the second sheet structure to form an inner cavity between the capillary structure of the first groove and the second sheet structure; and

and processing the first sheet structure and the second sheet structure to form an ultrathin hot tube plate with a heat conduction function.

Wherein: the slurry further comprises a first powder, a second powder and a solvent, wherein the first powder is a soldering tin alloy, and the second powder is a powder with surface weldability.

Wherein: in the step of heating the first sheet structure to form the capillary structure on the inner surface of the slurry, the method further comprises the following substeps:

heating the first sheet structure at a temperature below the melting point of the first powder; and

and heating the first sheet structure at a temperature higher than the melting point of the first powder and lower than the melting point of the second powder so that the slurry forms the hydrophilic capillary structure on the inner surface.

Wherein: the thickness of the capillary structure depends on the components of the first powder, the second powder and the solvent, the mixing ratio and the solid content of the slurry.

Wherein: before the step of pressing and sealing the first sheet-like structure and the second sheet-like structure to form the internal cavity between the capillary structure of the first groove and the second sheet-like structure, the method further comprises the following steps:

and forming a second groove on the second sheet structure, wherein the second groove is corresponding to the first groove.

Wherein: in the step of processing the first sheet structure and the second sheet structure to form the ultra-thin hot tube plate with heat conduction function, the method further comprises the following substeps:

manufacturing a conduit to communicate with the inner cavity;

pumping out air in the inner cavity by using the conduit to enable the inner cavity to form a negative pressure state;

injecting a working fluid into the internal cavity using the conduit in communication with the internal cavity; and

and sealing the conduit to enable the first sheet structure and the second sheet structure to form the ultrathin hot tube plate with the heat conduction function.

Wherein: the step of forming the first trench on the first sheet structure further includes:

forming a plurality of first grooves on the first sheet structure, wherein each first groove has a first end and a second end, the first end of the first groove is at least communicated with the first end of another first groove, the second end of the first groove is not communicated with the second end of another first groove, and the capillary structure is formed between the first groove and another first groove.

forming a plurality of first grooves on the first sheet structure, wherein each first groove has a first end and a second end, the first end of the first groove is at least communicated with the first end of another first groove, and the second end of the first groove is at least communicated with the second end of another first groove.

Wherein: in the step of heating the first sheet structure to form the capillary structure on the inner surface of the slurry, the step of heating the first sheet structure further comprises:

heating the first sheet structure to make the slurry form the capillary structure between the first end and the second end of the first groove and the connection between the second end of the first groove and the second end of another first groove and not form the capillary structure between the first end and the second end of another first groove; and

wherein, in the step of pressing and sealing the first sheet structure and the second sheet structure to form the internal cavity between the capillary structure of the first groove and the second sheet structure, the steps of:

and pressing and sealing the first sheet structure and the second sheet structure to form a cavity structure integrally formed by the first sheet structure and the second sheet structure, wherein the internal cavity is formed between the capillary structure of the first groove and the second sheet structure, and the cavity structure comprises an air-water flow channel with the capillary structure and the internal cavity and an auxiliary air channel without the capillary structure.

Wherein: the total thickness of the ultrathin hot tube plate is not less than 0.25mm and not more than 0.4 mm.

In summary, the method of manufacturing the ultra-thin heat pipe plate with the printed capillary structure of the present invention is different from the conventional concept of flattening the micro heat pipe or inserting the woven mesh and the fiber into the heat pipe plate by pressing the two sheet structures after being processed respectively. The method is beneficial to an electronic device system designer to keep larger heat dissipation management space application and design flexibility and better heat dissipation efficiency when designing the configuration of the internal parts of the electronic device. In addition, the formation of the capillary structure using the slurry is advantageous for efficiency in mass production. Compared with the prior art, the ultrathin heat tube plate manufactured by the method has a larger internal cavity to facilitate steam circulation, does not need to increase the thickness of the whole electronic device body, and meets the requirement of manufacturing an electronic device product which is thinner and has better heat dissipation effect.

Drawings

FIG. 1A: a top view of the first trench of the first sheet structure is shown in an embodiment of the invention.

FIG. 1B: a top view of an ultra-thin hot tube sheet made from a first sheet structure according to the embodiment of fig. 1A is shown.

FIG. 1C: a cross-sectional view along a-a of the ultra-thin hot tube sheet of the embodiment of fig. 1B is shown.

FIG. 2A: the first sheet structure with the printing paste forming capillary structure in one embodiment of the present invention is shown in the schematic structural diagram.

FIG. 2B: a schematic diagram of the structure of the ultra-thin hot tube sheet of the embodiment of fig. 2A is shown.

FIG. 2C: another perspective structural view of the ultra-thin hot tube sheet of the embodiment of fig. 2B is shown.

FIG. 3A: the first and second sheet structures are shown in another embodiment of the present invention.

FIG. 3B: a schematic diagram of the structure of the ultra-thin hot tube sheet of the embodiment of fig. 3A is shown.

FIG. 3C: another perspective structural view of the ultra-thin hot tube sheet of the embodiment of fig. 3B is shown.

Fig. 4A and 4B: top views of the first grooves and the printing paste forming capillaries of the first sheet structure are respectively shown in different embodiments of the present invention.

FIG. 5: a top view of the first grooves and the printing paste forming capillaries of the first sheet structure in yet another embodiment of the present invention is shown.

FIG. 6A: a top view of the first grooves and the printing paste forming capillaries of the first sheet structure in yet another embodiment of the present invention is shown.

FIG. 6B: a cross-sectional view along B-B of the first sheet structure in the embodiment of fig. 6A is shown.

FIG. 6C: a schematic diagram of the structure of the ultra-thin hot tube sheet in the embodiment of fig. 6B is shown.

Fig. 7A to 7C: a schematic diagram of the steps for forming the first sheet structure with the first capillary structure in the embodiment of fig. 6B is shown.

Fig. 8A to 8C: there is shown a schematic diagram of the steps for forming the first sheet structure with the first capillary structure in the embodiment of fig. 3A.

FIG. 9A: a mobile phone is shown.

FIG. 9B: a cross-sectional view along C-C of one embodiment of the invention as applied to the handset of fig. 9A is shown.

FIG. 9C: another embodiment of the invention applied to the handset of fig. 9A is shown in cross-section along C-C.

Fig. 10A and 10B: the slurry 6 and the capillary structure 4 of the present invention are respectively illustrated.

Fig. 11A to 11C: the structural schematic diagrams of the ultrathin hot tube plate in different embodiments are respectively shown.

Detailed Description

In order that the advantages, spirit and features of the invention will be readily understood and appreciated, embodiments thereof will be described and illustrated with reference to the accompanying drawings. It is to be understood that these embodiments are merely representative examples of the present invention, and that no limitations are intended to the scope of the invention or its corresponding embodiments, particularly in terms of the specific methods, devices, conditions, materials, and so forth.

In the description of the present invention, it is to be understood that the terms "longitudinal, transverse, upper, lower, front, rear, left, right, top, bottom, inner, outer" and the like refer to orientations or positional relationships based on those shown in the drawings, which are merely for convenience of description and simplicity of description, and do not indicate that the described devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

In addition, the indefinite articles "a", "an" and "an" preceding an apparatus or element of the invention are not intended to limit the number requirement (i.e., the number of occurrences) of the apparatus or element. Thus, "a" or "an" should be read to include one or at least one, and the singular form of a device or element also includes the plural form unless the number clearly indicates the singular form.

Please refer to fig. 1A to 1C and fig. 8A to 8C. Fig. 1A is a top view of the first sheet structure 1 and the first trench 10 according to an embodiment of the invention. FIG. 1B shows a top view of an ultra-thin hot tube sheet 5 made from the first sheet structure 1 according to the embodiment of FIG. 1A. FIG. 1C depicts a cross-sectional view A-A of the ultra-thin hot tube sheet 5 of the embodiment of FIG. 1B. Fig. 8A to 8C are schematic diagrams illustrating steps of forming the first sheet structure 1 having the first capillary structure 4 in the embodiment of fig. 3A. The invention relates to a method for manufacturing an ultrathin heat pipe plate 5 with a printing paste forming capillary structure 4, which comprises the following steps: providing a first sheet structure 1 and a second sheet structure 2; forming a first trench 10 on the first sheet structure 1; printing a paste 6 on an inner surface of the first trench 10; heating the first sheet structure 1 to make the slurry 6 form a capillary structure 4 on the inner surface; pressing and sealing the first sheet structure 1 and the second sheet structure 2 to form an inner cavity 51 between the capillary structure 4 of the first groove 10 and the second sheet structure 2; and processing the sealing device of the first sheet structure 1 and the second sheet structure 2 to form an ultra-thin heat pipe plate 5 with heat conduction function.

In the method of the present invention, the step of forming a first trench 10 in the first sheet structure 1 may be to chemically etch the first sheet structure 1 to form a trench, or to form a structure with a trench by using a mold when the first sheet structure 1 is manufactured. Printing a paste 6 on an inner surface of the first trench 10 may be performed by using a steel plate 7 having holes corresponding to the holes of the steel plate 7 above the first trench 10, as shown in fig. 8A. When the slurry 6 is pushed from one end of the first sheet structure 1 to the other end, the slurry 6 falls into the first grooves 10, as shown in fig. 8B. Thereafter, the first sheet structure 1 carrying the slurry 6 is heated to vaporize the liquid phase substance in the slurry 6, and the mixed powder in the slurry 6 collapses by heating and adheres to the inner surface to form the capillary structure 4, as shown in fig. 8C. The second sheet structure 2 is then pressed onto the first sheet structure 1, and the joint edges of the first sheet structure 1 and the second sheet structure 2 are sealed, so that an internal cavity 51 is formed between the capillary structure 4 of the first groove 10 and the second sheet structure 2, as shown in fig. 1C. Finally, the first sheet structure 1 and the second sheet structure 2 are processed further to form an ultrathin heat pipe plate 5.

One conventional method of manufacturing a flat heat conducting element is to flatten a round or long-strip-shaped micro heat conducting tube to be placed in an electronic device, and the thickness and width of the flat heat conducting element manufactured by the method are limited. However, the design flexibility of this method is very low, the cross-sectional area of the inner cavity is small, and the heat conductivity is low. The invention utilizes printing slurry to heat to form a capillary structure, and then two structural sheets are superposed to form a heat pipe plate, the shape of the heat pipe plate can be changed along with the design of the structural sheets, and the sectional area of an inner cavity can be designed to be maximized, thereby greatly improving the heat dissipation efficiency of the whole electronic device.

In addition, in another conventional method, the fiber or woven copper mesh is laid in the groove of the heat pipe plate, which not only makes the manufacturing process difficult to be automated, but also makes the fiber or woven copper mesh difficult to control the thickness and yield, and also easily causes the penetration of gas and liquid in the cavity to affect the heat conduction efficiency of the heat pipe plate. The capillary structure is formed by heating the printed slurry, is convenient to operate and produce in mass, the slurry naturally collapses and is formed after heating, and the capillary structure is not fully distributed in the inner cavity, so that the gas and the liquid in the same groove cavity have clear and separate flow channels from top to bottom without influencing the heat conduction effect of the heat pipe plate. Therefore, the existing heat conduction element manufacturing concept is broken through, and a heat conduction element with higher efficiency or thinner can be formed under the limitation of the existing industrial technology. Moreover, the ultra-thin heat pipe plate can be rapidly produced in large quantity, and the development of miniaturization of the portable electronic device is driven.

Please refer to fig. 2A to 2C and fig. 3A to 3C. Fig. 2A shows a schematic structural diagram of the first sheet structure 1 with the printing paste forming capillary structure 4 according to an embodiment of the present invention. Fig. 2B depicts a schematic of the structure of the ultra-thin hot tube sheet 5 of the embodiment of fig. 2A. FIG. 2C illustrates another perspective view of the ultra-thin heat pipe plate 5 of the embodiment of FIG. 2B. Fig. 3A is a schematic structural diagram of a first sheet structure 1 and a second sheet structure 2 according to another embodiment of the invention. Fig. 3B depicts a schematic of the structure of the ultra-thin hot tube sheet 5 of the embodiment of fig. 3A. FIG. 3C illustrates another perspective view of the ultra-thin heat pipe plate 5 of the embodiment of FIG. 3B.

In an embodiment of the present invention, before the step of pressing and sealing the first sheet-like structure 1 and the second sheet-like structure 2 to form the internal cavity 51 between the capillary structure 4 of the first trench 10 and the second sheet-like structure 2, the method further includes a step of: a second trench 20 is formed on the second sheet structure 2, and the position of the second trench 20 corresponds to the position of the first trench 10, as shown in fig. 3A. After the first sheet structure 1 and the second sheet structure 2 are pressed, the inner cavity 51 formed by the first groove 10 and the second groove 20 is larger, as shown in fig. 3B and 3C. In other words, compared to the embodiment of fig. 2A to 2C, the embodiment of fig. 3A to 3C has a larger space for allowing gas to flow in the ultra-thin heat pipe plate 5, and the efficiency of heat conduction is more excellent.

In the step of processing the sealing device of the first sheet structure 1 and the second sheet structure 2 to form the ultra-thin heat pipe plate 5 with heat conduction function in the method, the method further comprises the following substeps: manufacturing a conduit to communicate with the internal cavity 51, specifically, when the first sheet structure 1 and the second sheet structure 2 are pressed, placing a conduit between the first sheet structure 1 and the second sheet structure 2, and after the pressing, one end of the conduit communicates with the internal cavity 51, and the other end communicates with the outside of the first sheet structure 1 and the second sheet structure 2; or after the first sheet structure 1 and the second sheet structure 2 are pressed, a hole is drilled in the first sheet structure 1 or the second sheet structure 2, and a conduit is inserted to communicate the inner cavity. The air in the internal cavity 51 is then evacuated by the catheter to create a negative pressure in the internal cavity 51. The working fluid is then injected or sucked into the internal cavity using a conduit communicating with the internal cavity 51. Finally, the conduit is sealed, so that the close fit device of the first sheet structure 1 and the second sheet structure 2 forms an ultrathin heat tube plate 5 with the heat conduction function.

Please refer to fig. 8A to 8C, fig. 10A and 10B. Fig. 10A and 10B are schematic diagrams respectively illustrating the slurry 6 and the capillary structure 4 according to the present invention. The slurry 6 of the present invention further comprises a first powder 61, a second powder 62 and a solvent 63, as shown in fig. 10A. The first powder 61 is a solder alloy. The second powder 62 is a powder having surface solderability, and may be copper or a metal such as a copper alloy. The melting point of the second powder 62 is higher than that of the solder. When the first sheet structure 1 carrying the slurry 6 is heated, the solvent 63 evaporates to reduce the volume of the slurry 6. Further, the first powder 61 is melted, and the plurality of second powders 62 are welded to each other, and the second powders 62 are fixed to the inner surface of the first groove 10 to form the capillary structure 4, as shown in fig. 10B.

The step of heating the first sheet structure 1 to form the capillary structure 4 on the inner surface of the slurry 6 further comprises the following substeps: the first sheet structure 1 is heated at a temperature below the melting point of the first powder 61. The low temperature heating of this step is to evaporate the solvent 63. After the solvent 63 is driven off, the first sheet structure 1 is heated at a temperature higher than the melting point of the first powder 61 and lower than the melting point of the second powder 62, and the high temperature heating in this step melts the first powder 61 and causes it to be welded to the second powder 62 and the first grooves 10. Finally, the slurry 6 forms a capillary structure 4 on the inner surface. The porosity of the capillary structure 4 gives it a capillary force.

When printing the paste 6 on the first sheet structure 1, the paste 6 will in principle fill the first grooves 10. The thickness of the capillary structure 4 described in the present invention depends on the composition, mixing ratio, and solid content of the slurry 6 of the first powder 61, the second powder 62, and the solvent 63. When the solid content is high, the thickness of the capillary structure 4 formed after heating is large; when the solid content is low, the thickness of the capillary structure 4 formed after heating is small. Therefore, the formula of the slurry 6 and the printing thickness can be adjusted to control the thickness of the heated capillary structure 4, so as to control the size of the internal cavity 51 and maintain the elasticity of the ultrathin heat pipe plate 5 during design.

Please refer to fig. 2B and fig. 4A. FIG. 4A is a top view of the first trench 10 of the first sheet structure 1 according to one embodiment of the present invention. In this embodiment, the step of forming the first trench 10 on the first sheet structure 1 of the method further comprises: a plurality of first trenches 10 are formed on the first sheet structure 1, wherein each first trench 10 has a first end 101 and a second end 102, the first end 101 of one first trench 10 is connected to at least the first end 101 of another first trench 10, the second end 102 of the first trench 10 is not connected to the second end 102 of another first trench 10, and the capillary structure is formed between the first trench and the another first trench. The first end 101 can be used as a heat absorbing end contacting a heat generating source, where the working fluid in the capillary structure is heated and evaporated into a gas, and the gas moves along the inner cavity 51 formed by the first groove 10 toward the second end 102. The second end 102 is a condensation end and a heat dissipation end of the vapor, and condenses and dissipates latent heat generated by the phase change at the heat absorption end. Therefore, in practical applications, the first end 101 may have a relatively small dispersion range to match a Hot Spot (Hot Spot) region with high heat density, and the second end 102 may have a relatively large dispersion range to direct heat energy to different locations. Moreover, the connection of the first ends 101 of the first sheet structures 1 can balance the heat dissipation of the internal cavity 51 of the ultra-thin heat pipe plate 5, and avoid the work of heat energy conduction from concentrating on the internal cavity 51 formed by some first grooves 10, which wastes the heat conduction efficiency.

Please refer to fig. 4B, fig. 5, and fig. 6A to fig. 6C. Fig. 4B shows a top view of the first grooves 10 and the printing paste forming capillary structures 4 of the first sheet structure 1 in a different embodiment from fig. 4A. Fig. 5 shows a top view of the first grooves 10 and the printing paste forming capillary structures 4 of the first sheet structure 1 according to yet another embodiment of the present invention. Fig. 6A shows a top view of the first grooves 10 and the printing paste forming capillary structures 4 of the first sheet structure 1 according to still another embodiment of the present invention. FIG. 6B illustrates a cross-sectional view along B-B of the first sheet structure 1 in the embodiment of FIG. 6A. FIG. 6C shows a schematic structural view of the ultra-thin hot tube sheet 5 in the embodiment of FIG. 6B. In these embodiments, the step of forming the first trench 10 on the first sheet structure 1 of the method further comprises: a plurality of first trenches 10 are formed on the first sheet structure 1, wherein each first trench 10 has a first end 101 and a second end 102, the first end 101 of one first trench 10 is connected to at least the first end 101 of another first trench 10, and the second end 102 of the first trench 10 is connected to at least the second end 102 of another first trench 10. The configuration of fig. 4B is substantially the same in shape and function as the above-mentioned embodiment, and the greatest difference is that in this configuration, the second ends 102 of every two first trenches 10 are also connected. Therefore, the flowing directions of the liquid and the gas in different flow passages can be more definite. Fig. 5 and 6A are schematic views of another structure.

Please refer to fig. 7A to 7C. Fig. 7A to 7C are schematic diagrams illustrating steps of forming the first sheet structure 1 with the first capillary structure 4 in the embodiment of fig. 6B. To form the first sheet structure 1 shown in fig. 4B, 5 or 6A, the step of printing the paste 6 on the first sheet structure 1 may be to print the paste 6 only into a part of the first grooves by using the barrier of the steel plate 7, as shown in fig. 7A and 7B. In the step of heating the first sheet structure 1 to form the capillary structure 4 on the inner surface of the slurry 6, the method further comprises: the first sheet structure 1 is heated to make the slurry 6 form the capillary structure 4 between the first end 101 and the second end 102 of the first groove 10 and the connection between the second end 102 of the first groove 10 and the second end 102 of another first groove 10 and adhere to the inner surface, and the capillary structure 4 is not formed between the first end 101 and the second end 102 of another first groove 10, as shown in fig. 4B, fig. 5 or fig. 6A.

Please refer to fig. 4B, fig. 5, and fig. 6A to fig. 6C. In addition, in the step of pressing and sealing the first sheet-like structure 1 and the second sheet-like structure 2 to form the internal cavity 51 between the first trench 10 and the second sheet-like structure 2, the steps further include: the first sheet-like structure 1 and the second sheet-like structure 2 are pressed and sealed, so that the first sheet-like structure 1 and the second sheet-like structure 2 form a cavity structure integrally, an internal cavity 51 is formed between the first groove 10 and the second sheet-like structure 2, and the cavity structure includes an air/water flow passage 511 having the capillary structure 4 and the internal cavity 51 and an auxiliary air passage 510 without the capillary structure 4, as shown in fig. 6C. The auxiliary air passage 510 lacks a capillary structure and serves only as a flow passage for vapor. The condensed working fluid in the capillary structure of the second end 102 will tend to flow from the gas-water flow passage 511 to the first end 101. On the other hand, the hot vapor at the first end 101 can reach the second end 102 through the auxiliary air duct 510 and the air-water flow passage 511 at the same time. By forming the auxiliary air duct 510, the space for latent heat generated by the phase change in the heat absorption region to be conducted and circulated is larger, which is very convenient for manufacturing the ultra-thin heat pipe plate while maintaining a larger heat dissipation capability. In the present invention, the sectional area of the auxiliary air passage 510 is not limited to be larger than, equal to or smaller than the air-water flow passage 511.

Please refer to fig. 11A to 11C. Fig. 11A to 11C are schematic structural diagrams illustrating an ultra-thin heat pipe plate in different embodiments, respectively. The total thickness of the ultra-thin heat pipe plate 5 in the present invention is not less than 0.25mm, and may not be more than 0.4 mm. The corresponding height design is introduced below for various thickness requirements.

The design of fig. 11A can be utilized when the total thickness of the ultra-thin hot tubesheet 5 is 0.4 mm. Wherein the first sheet structure has a maximum thickness a of 0.25 mm; the maximum thickness b of the second sheet structure is 0.15 mm; the first lamellar structure minimum thickness c (thickness at the first groove) is 0.1 mm; the second sheet structure minimum thickness d (thickness at the second groove) is 0.1 mm; the height e between the first groove and the second groove is 0.2 mm. The thickness of the capillary structure 4 is 0.1mm, leaving a space height of 0.1mm for the gas flow to pass through.

The design of fig. 11A or 11B can be utilized when the total thickness of the ultra-thin heat pipe plate 5 is 0.35 mm.

For example, in FIG. 11A, the first sheet structure has a maximum thickness a of 0.2 mm; the maximum thickness b of the second sheet structure is 0.15 mm; the first lamellar structure minimum thickness c (thickness at the first groove) is 0.1 mm; the second sheet structure minimum thickness d (thickness at the second groove) is 0.1 mm; the height e between the first groove and the second groove is 0.15 mm. The thickness of the capillary structure 4 is 0.075mm, leaving a space height of 0.075mm through which the gas flow can pass.

Or for example in fig. 11B, the first sheet structure maximum thickness a is 0.25 mm; the maximum thickness b of the second sheet-like structure is 0.1 mm; the first lamellar structure minimum thickness c (thickness at the first groove) is 0.1 mm; the minimum thickness d of the second sheet structure (without second grooves) is 0.1 mm; the height e between the first groove and the second sheet structure is 0.15 mm. The thickness of the capillary structure 4 is 0.075mm, leaving a space height of 0.075mm through which the gas flow can pass.

The design of fig. 11C can be utilized when the total thickness of the ultra-thin heat pipe plate 5 is 0.30 mm. Wherein the first sheet structure has a maximum thickness a of 0.2 mm; the maximum thickness b of the second sheet-like structure is 0.1 mm; the first lamellar structure minimum thickness c (thickness at the first groove) is 0.1 mm; the minimum thickness d of the second sheet structure (without second grooves) is 0.1 mm; the height e between the first groove and the second sheet structure is 0.1 mm. The thickness of the capillary structure 4 at the air-water flow passage 511 is 0.05mm, and the remaining space height of 0.05mm is used for air flow to pass through. There is no capillary structure at the secondary air duct 510, leaving a space height of 0.1 for the air flow to pass through.

The thickness or height of the individual elements can be achieved by conventional industry techniques. However, the present invention breaks through the concept of the existing capillary structure made of the thermal conductive element, and the thickness of the formed capillary structure and the height of the air passage internal cavity are controlled by printing the slurry and controlling the solid content, so that the thermal conductive characteristic with high efficiency can be maintained when the ultrathin heat pipe plate is manufactured. In addition, the ultrathin heat pipe plate manufactured by the invention can be applied to electronic products such as smart mobile phones in a large scale.

Please refer to fig. 9A to 9C. FIG. 9A shows a mobile phone. FIG. 9B shows a cross-sectional view along C-C of one embodiment of the present invention applied to the handset of FIG. 9A. FIG. 9C is a cross-sectional view taken along C-C of another embodiment of the present invention applied to the handset of FIG. 9A. The components of the mobile phone 9 include at least a back cover 90, a screen 91, a circuit board 93, a central processor 931, a center frame 94, a bezel 96, and a battery 98. In the existing mobile phone manufacturing technology, the ways of adhering a mobile phone heating source (central processing unit) to a circuit board are roughly divided into two types. One is that the central processing unit faces the back cover, and the other is that the central processing unit faces the screen. If the cpu 931 is oriented toward the back cover 90, as shown in fig. 9B, the ultra-thin heat pipe plate 5 made by the present invention can be placed between the back cover 90 and the cpu 931 to quickly direct heat energy from the area near the cpu 931 to the back cover 90 or elsewhere on the bezel 96. Furthermore, an ultra-thin heat shield 7 may be added between the ultra-thin heat pipe plate 5 and the back cover 90 to prevent heat energy from concentrating on the surface of the back cover 90 near the central processor 931, which may cause burning. If the cpu 931 faces the screen 91, as shown in fig. 9C, the ultra-thin heat pipe plate 5 made by the present invention can be placed on the middle frame 94 or between the middle frame 94 and the cpu 931 to rapidly guide the heat energy from the area near the cpu 931 to the border 96.

In summary, the method for manufacturing the ultra-thin heat pipe plate with the printing paste forming capillary structure of the present invention processes and presses two sheet structures separately, which is different from the conventional forming capillary structure process of laying and weaving copper mesh and fiber. The method is beneficial to an electronic device system designer to keep larger heat dissipation management space application and design flexibility and better heat dissipation efficiency when designing the configuration of the internal parts of the electronic device. In addition, the formation of the capillary structure using the printing paste is advantageous in terms of efficiency in mass production and reduction in production cost. Compared with the prior art, the ultrathin heat tube plate manufactured by the method has a larger internal cavity to facilitate steam circulation, does not need to increase the thickness of the whole electronic device body, and meets the requirement of manufacturing an electronic device product which is thinner and has better heat dissipation effect.

The above detailed description of the preferred embodiments is intended to more clearly illustrate the features and spirit of the present invention, and is not intended to limit the scope of the present invention by the preferred embodiments disclosed above. On the contrary, it is intended to cover various modifications and equivalent arrangements included within the scope of the claims. The scope of the claims is thus to be accorded the broadest interpretation so as to encompass all such modifications and equivalent arrangements as is within the scope of the appended claims.

Claims

1. A method of making an ultra-thin hot tube sheet having a printed capillary structure, comprising the steps of:

providing a first sheet structure and a second sheet structure;

forming a plurality of first trenches on the first sheet structure, wherein each first trench has a first end and a second end, the first end of the first trench is at least connected to the first end of another first trench, and the second end of the first trench is at least connected to the second end of another first trench in each two first trenches;

printing a slurry on an inner surface of the first groove;

heating the first sheet structure to make the slurry form a capillary structure between the first end and the second end of the first groove and the connection between the second end of the first groove and the second end of another first groove and not form the capillary structure between the first end and the second end of another first groove;

pressing and sealing the first sheet structure and the second sheet structure to form a cavity structure, wherein an internal cavity is formed between the capillary structure of the first groove and the second sheet structure, and the cavity structure comprises an air-water flow channel with the capillary structure and the internal cavity and an auxiliary air channel without the capillary structure; and

2. The method of claim 1, wherein: the slurry further comprises a first powder, a second powder and a solvent, wherein the first powder is a soldering tin alloy, and the second powder is a powder with surface weldability.

3. The method of claim 2, wherein: in the step of heating the first sheet structure to make the slurry form a capillary structure between the first end and the second end of the first groove and the connection between the second end of the first groove and the second end of another first groove and adhere to the inner surface, the method further comprises the following substeps:

and heating the first sheet structure at a temperature higher than the melting point of the first powder and lower than the melting point of the second powder so that the slurry forms the capillary structure with hydrophilicity on the inner surface.

4. The method of claim 2, wherein: the thickness of the capillary structure depends on the components of the first powder, the second powder and the solvent, the mixing ratio and the solid content of the slurry.

5. The method of claim 1, wherein: before the step of pressing and sealing the first sheet structure and the second sheet structure to form the cavity structure by the first sheet structure and the second sheet structure, and forming the internal cavity between the capillary structure of the first groove and the second sheet structure, the method further comprises the following steps:

6. The method of claim 1, wherein: in the step of processing the first sheet structure and the second sheet structure to form the ultra-thin hot tube plate with heat conduction function, the method further comprises the following substeps:

manufacturing a conduit to communicate with the inner cavity;

sealing the conduit so that the first sheet structure and the second sheet structure form the ultra-thin hot tube sheet with a heat conducting function.

7. The method of claim 1, wherein: the total thickness of the ultrathin hot tube plate is not less than 0.25mm and not more than 0.4 mm.