A customizable capillary wick structure, method of fabrication, and method of design

Abstract

The application relates to a customizable capillary wick structure, a preparation method and a design method in the technical field of wick structures of heat conduction plates. The capillary wick structure comprises one or more layer structures, when the layer structures are two or more, the two or more layer structures are arranged in a stack from top to bottom; each layer structure comprises a plurality of units arranged in an array; each unit comprises a plurality of support columns connected with each other, and a plating layer subjected to hydrophilic treatment is formed on the surface of the support column. The capillary wick structure has excellent liquid absorption performance, can improve the heat dissipation efficiency of the heat conduction plate, better meets the heat dissipation demand of electronic devices, the design method and the preparation method can optimize the structure parameters such as the size, thickness and pore distribution of the wick according to actual heat dissipation demand, realize customized design, effectively improve the liquid absorption performance of the wick, and provide a new scheme for customized design and preparation of the capillary wick of the heat conduction plate.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of wick structures of heat spreading plates, in particular to a customizable capillary wick structure, a preparation method and a design method. BACKGROUND

[0002] With the rapid development of electronic technology, electronic devices tend to be designed in a small size, which causes the temperature of the electronic devices to rapidly rise in a narrow space, and the chip is damaged or the service life is shortened for a long time. In order to enable the electronic device to work stably for a long time, a heat spreading plate, an efficient passive heat dissipation technology, is introduced. The heat spreading plate can uniformly distribute heat to a larger area of the device, and is commonly used in the fields of electronic products, optical devices and heat exchange systems. The heat spreading plate can effectively reduce the temperature of the device and improve the reliability and performance of the device by increasing the heat transfer area, improving the thermal conductivity and reducing the thermal resistance. However, the traditional heat spreading plate is prepared by etching, pressure welding and casting, and the design of the capillary core structure in the heat spreading plate is relatively difficult to effectively control, and the wicking performance is poor, so that the heat dissipation efficiency of the heat spreading plate for electronic devices, especially small electronic devices, is low.

[0003] Therefore, the application is provided. SUMMARY

[0004] In view of the problems in the background art, the application provides a customizable capillary wick structure, a preparation method and a design method. The capillary wick structure has excellent wicking performance, can improve the heat dissipation efficiency of the heat spreading plate, and better meets the heat dissipation demand of the electronic device.

[0005] According to a first aspect of the application, a capillary wick structure is provided, which comprises one or more layer structures, when the layer structures are two or more, the two or more layer structures are arranged in a stack one above another; each layer structure comprises a plurality of units arranged in an array; each unit comprises a plurality of support columns connected to each other, and the surface of the support column is formed with a hydrophilic treated plating layer.

[0006] In some embodiments of the application, the thickness of the capillary wick structure is 0.1mm-1mm, and the length and width of the capillary wick structure are independently 10mm-100mm.

[0007] In some embodiments of the application, the overall length and width of the unit are independently 450-550pm, and the overall height of the unit is 100-1000pm.

[0008] In some embodiments of the application, the diameter of the support column is 30-100pm.

[0009] In some embodiments of the present invention, the multiple support columns of the unit are cross-connected to form a body-centered cubic structure or a face-centered cubic structure.

[0010] In some embodiments of the present invention, the bottom and top of the capillary core structure are provided with a border around the outer edge of each unit.

[0011] According to a second aspect of the present invention, a method for customizing the above-mentioned capillary wick structure is provided, comprising the following steps: integrating slices through three-dimensional modeling and then performing photopolymerization printing to initially obtain a capillary wick structure; then forming a coating on the surface of the capillary wick structure and performing hydrophilic treatment on the coating.

[0012] In some embodiments of the present invention, the coating preparation includes the following steps: first, roughening the surface of the capillary wick structure with chromic acid, then sensitizing it with a sensitizer, activating it with an activator after sensitization, and then placing the treated capillary wick structure in a chemical copper / nickel plating solution at 40°C for 40-50 minutes and then removing it to complete the copper / nickel plating.

[0013] In some embodiments of the present invention, the hydrophilic treatment involves soaking the sample in a hydrogen peroxide solution for 3-5 minutes.

[0014] According to a third aspect of the present invention, a method for designing the above-described capillary wick structure is provided, comprising the following steps:

[0015] Based on the heat dissipation requirements of specific electronic devices, the liquid absorption volume V0 and liquid absorption speed U0 of the capillary wick structure are set, and the diameter of the support column, the length, width and height of the unit, and the number of layers of the layer structure are designed.

[0016] The designed capillary wick structure was fabricated using 3D printing, and a coating was prepared and a hydrophilic treatment was completed.

[0017] The performance of the obtained capillary core structure was tested to obtain the liquid absorption volume V1 and the liquid absorption speed U1.

[0018] Determine whether V1 is greater than or equal to V0 and whether U1 is greater than or equal to U0. If the conditions are met, the designed capillary liquid absorption core structure meets the standard. If the conditions are not met, continue to optimize the diameter of the support column, the length, width and height of the unit or the number of layers in the layer structure, and carry out preparation and testing until the conditions are met.

[0019] The capillary wick structure provided by this invention consists of interconnected support pillars forming units, which are then arrayed in the x and y directions to obtain a layered structure. Depending on the needs, a single layer or multiple layers can be stacked and connected to form the capillary wick structure. Furthermore, a coating is formed on the surface of the support pillars and hydrophilic treatment is applied, which effectively improves the liquid absorption performance of the capillary wick structure, thereby enhancing the heat dissipation efficiency of the vapor chamber and better meeting the heat dissipation requirements of electronic devices. This invention also provides a clear design method for improving the liquid absorption performance of the capillary wick structure. For customized heat dissipation devices, 3D printing is used to print wick structures of different materials on a substrate. The capillary suction experimental platform is used to recreate the vapor chamber's liquid absorption process. By changing variables such as the capillary wick structure, number of layers, and space ratio, liquid absorption capacity data under different structures are recorded. This clearly reveals the influence of the height, number of layers, internal structure, and space ratio of the wick unit in the customized capillary wick on its liquid absorption volume and suction rate. This provides a theoretical basis for the numerical design of vapor chamber capillary wick structures and has significant practical significance and technological development for optimizing the design of ultra-thin vapor chambers. Attached Figure Description

[0020] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0021] Figure 1 This is a schematic diagram of the overall structure of the capillary liquid absorption core structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the liquid-absorbing core unit structure without internal support columns in this invention;

[0023] Figure 3 This is a schematic diagram of the liquid-absorbing core unit structure with double layers and no internal support columns in this invention;

[0024] Figure 4 This is a schematic diagram of the liquid-absorbing core unit structure with a body-centered cubic internal structure in this invention;

[0025] Figure 5 This is a schematic diagram of the double-layer body-centered cubic liquid absorption core unit structure in this invention;

[0026] Figure 6 This is a schematic diagram of the single-layer, frameless, body-centered cubic liquid-absorbing core assembly unit structure in this invention;

[0027] Figure 7 This is a schematic diagram of the double-layer, frameless, body-centered cubic liquid-absorbing core assembly unit structure in this invention;

[0028] Figure 8This is a schematic diagram of the small-sized, single-layer, frameless, body-centered cubic liquid-absorbing core assembly unit structure of the present invention;

[0029] Figure 9 This is a schematic diagram of the small-sized, double-layered, frameless, body-centered cubic liquid-absorbing core assembly unit structure of the present invention.

[0030] Figure 10 This is a comparison chart of capillary suction curves for the eight structures in this invention;

[0031] Figure 11 This is a comparison chart of the capillary suction rates of the eight structures in this invention.

[0032] The labels in the attached diagram are as follows: 1. Support column; 2. Frame. Detailed Implementation

[0033] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0034] In the following description, when referring to the accompanying drawings, the same numbers in different drawings denote the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0035] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, in the description of this application, unless otherwise stated, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0036] This application provides a capillary liquid absorption core structure, such as... Figure 1 As shown, the capillary liquid absorption core structure includes one or more layer structures. When there are two or more layer structures, the two or more layer structures are stacked one on top of the other. Each layer structure includes multiple units arranged along the array. Each unit includes multiple interconnected support pillars 1, and the surface of the support pillars 1 is coated with a hydrophilic coating.

[0037] By using the capillary wick structure in this technical solution, the support pillars 1 are interconnected to form units, and the units are then arrayed in the x and y directions to obtain a layer structure. Then, as needed, a single layer structure or stacked layer structures can be selected as the capillary wick structure. Furthermore, a coating is formed on the surface of the support pillars 1 and hydrophilic treatment is performed, which can effectively improve the liquid absorption performance of the capillary wick structure, thereby improving the heat dissipation efficiency of the heat spreader and better meeting the heat dissipation requirements of electronic devices.

[0038] In some embodiments of the present invention, the thickness of the capillary wick structure is between 0.1 mm and 1 mm, and the length and width of the capillary wick structure are independently between 10 mm and 100 mm; for example, the thickness of the capillary wick structure is 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1.0 mm, etc., and the length (or width) of the capillary wick structure is 10 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, or 100 mm, etc.

[0039] Furthermore, the overall length and width of the structural unit are independently between 450-550μm, and the overall height of the unit is between 100-1000μm; for example, the overall length (or width) of the unit is 450μm, 460μm, 470μm, 480μm, 490μm, 500μm, 510μm, 520μm, 530μm, 540μm or 550μm, etc., and the overall height of the unit is 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm or 1000μm, etc.

[0040] Furthermore, the diameter of the support column 1 is between 30-100μm, for example, the diameter of the support column 1 is 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm or 100μm, etc.

[0041] Specifically, in this embodiment, the thickness and length and width of the capillary wick structure can be set according to the specifications and heat dissipation requirements of a specific electronic device, and the length, width and height of the unit and the diameter of the support column 1 can be set to meet the heat dissipation requirements of the specific electronic device.

[0042] In some embodiments of the present invention, such as Figure 1 As shown, multiple supporting columns 1 of the unit are cross-connected to form a body-centered cubic structure or a face-centered cubic structure.

[0043] For example, a support column 1 is arranged at each pair of opposite vertices of a cube or cuboid, and a total of 4 support columns 1 are connected at the center of the cube or cuboid to form a body-centered cubic structure.

[0044] In other embodiments, the multiple support columns 1 can also form a four-sided frame structure.

[0045] In some embodiments of the present invention, such as Figure 1 As shown, the bottom and top of the capillary suction core structure are provided with a frame 2 on the outer ring of each unit.

[0046] By setting a frame 2 on the outer ring of each unit at the bottom and top of the capillary core structure, and setting each unit between the bottom and top of the capillary core structure as a frameless structure 2, the structural stability of the capillary core structure can be guaranteed. Moreover, the design of the inner frameless layer 2 increases the space ratio of the support column 1, which greatly improves the suction rate of the capillary core structure.

[0047] In some embodiments of the present invention, the materials of the capillary wick structure include, but are not limited to, resin, ceramic or metal materials; the capillary wick structure can be prepared on one side of a heat sink such as a metal-based, polymer-based, or ceramic-based heat sink.

[0048] This application provides a method for custom-preparing the above-mentioned capillary wick structure, comprising the following steps:

[0049] After integrating slices through 3D modeling, a capillary wick structure is initially obtained by photopolymerization printing. Then, a coating is made on the surface of the capillary wick structure and the coating is hydrophilic.

[0050] In some embodiments of the present invention, the coating preparation includes the following steps: first, roughening the surface of the capillary wick structure with chromic acid, then sensitizing it with a sensitizer, activating it with an activator after sensitization, and then placing the treated capillary wick structure into a chemical copper / nickel plating solution at 40°C for 40-50 minutes and then removing it to complete the copper / nickel plating.

[0051] Furthermore, the capillary core structure is cleaned with water and then roughened with chromic acid.

[0052] In some embodiments of the present invention, the hydrophilic treatment involves soaking the sample in a hydrogen peroxide solution for 3-5 minutes to achieve hydrophilicity and improve its water absorption performance.

[0053] In some embodiments of the present invention, the precision of photopolymerization printing for preparing capillary wick structures is between 10 micrometers and 2 centimeters.

[0054] This application provides a method for designing the above-mentioned capillary wick structure, comprising the following steps:

[0055] Based on the heat dissipation requirements of specific electronic devices, the liquid absorption volume V0 and liquid absorption speed U0 of the capillary wick structure are set, and the diameter of the support column, the length, width and height of the unit, and the number of layers of the layer structure are designed.

[0056] The designed capillary wick structure was fabricated using 3D printing, and a coating was prepared and a hydrophilic treatment was completed.

[0057] The performance of the obtained capillary core structure was tested to obtain the liquid absorption volume V1 and the liquid absorption speed U1.

[0058] Determine whether V1 is greater than or equal to V0 and whether U1 is greater than or equal to U0. If the conditions are met, the designed capillary liquid absorption core structure meets the standard. If the conditions are not met, continue to optimize the diameter of the support column, the length, width and height of the unit or the number of layers in the layer structure, and carry out preparation and testing until the conditions are met.

[0059] In some embodiments of the present invention, the capillary suction core structure performance is tested using a capillary suction performance testing platform, which consists of a high-precision analytical balance, a mobile carrier module platform, a beaker, a computer, a clamp, and a support.

[0060] The specific operating steps for testing the structural performance of the capillary absorber are as follows:

[0061] 1) Add a measured amount of ultrapure water to the beaker, place the beaker on the mobile module platform, and confirm that the platform is level and not tilted.

[0062] 2) Turn on the high-precision analytical balance and zero it. Open the computer's recording software and link the balance to the computer to ensure real-time data synchronization.

[0063] 3) Fix the capillary core structure below the high-precision analytical balance, and control the moving carrier platform to move upward until the capillary core structure located on the chuck is submerged 1-2 mm below the liquid surface.

[0064] 4) After the reading of the high-precision analytical balance has stabilized, move the mobile carrier platform downwards to separate the beaker and the capillary suction core structure.

[0065] 5) By processing and analyzing the data output by the analytical balance on the computer, the liquid absorption performance of the capillary core structure can be obtained.

[0066] The design method of this invention can improve the liquid absorption capacity of the capillary wick structure by adjusting its height, number of layers, internal structure, support column diameter, and unit structure length and width, and provide faster liquid absorption performance to accelerate the heat transfer process from the evaporation end to the condensation end of the heat spreader. It reveals the influence of various factors on the liquid absorption performance of the capillary wick structure and can realize the customized design of the capillary wick structure.

[0067] The present invention also provides the following experimental examples.

[0068] Liquid absorption performance test of different capillary wick structures

[0069] (1) As Figure 2 As shown, the design model has a unit length and width of 200μm and an overall structural height of 100μm. These units are then arrayed and combined into a rectangular structure with a length of 40mm and a width of 10mm.

[0070] (2) Figure 3 As shown, the design model has a unit length and width of 200μm and an overall structural height of 200μm. It is a double-layer structure of (1), and the array is a rectangular structure with the same length and width as (1).

[0071] (3) Figure 4 As shown, the design model has a unit length and width of 500μm, an overall structural height of 140μm, and an internal support column diameter of 50μm. This unit adds a body-centered cubic support column structure to (1), and the array is a rectangular structure with the same length and width as (1).

[0072] (4) Figure 5 As shown, the design model has a unit length and width of 500μm, an overall structural height of 280μm, and an internal support column diameter of 50μm. It is a double-layer design of (3), and the array is a rectangular structure with the same length and width as (1).

[0073] (5) Figure 6 As shown, the design model has a unit length and width of 500μm, an overall structural height of 500μm, and an internal support column diameter of 100μm. Compared with (3), the unit height is increased and the internal support column diameter is increased. The array is a rectangular structure with the same length and width as (1).

[0074] (6) Figure 7 As shown, the design model has a unit length and width of 500μm, an overall structural height of 1000μm, and an internal support column diameter of 100μm. It is a double-layer structure of (5), and the array is a rectangular structure with the same length and width as (1).

[0075] (7) Figure 8As shown, the design model is a small-sized single-layer body-centered cubic liquid absorption core combination unit structure with no inner frame. The unit length and width are both 250μm, the overall structural height is 250μm, the internal support column diameter is 50μm, and the array is a rectangular structure with the same length and width as (1).

[0076] (8) Figure 9 As shown, the design model is a schematic diagram of a small-sized double-layer body-centered cubic liquid absorption core combination unit with no inner frame. The unit length and width are both 250μm, the overall structural height is 500μm, and it is a double-layer structure of (7). The diameter of the internal support column is 50μm, and the array is a rectangular structure with the same length and width as (1).

[0077] The 3D models (1) to (8) were sliced ​​using software, and the images were then transmitted to a 3D printing device for printing the liquid-absorbing core structure on a copper substrate. The copper substrate was 50mm long, 15mm wide, and 0.08mm thick, and the distance between the printed liquid-absorbing core and the edge was <2mm. After printing, the surface was chemically plated with copper and then hydrophilic to ensure the liquid absorption performance of the liquid-absorbing core structure. After drying, the capillary liquid-absorbing core structure was tested for suction performance on a capillary suction performance testing platform. The liquid-absorbing core was fixed on the clamp under the balance, and the balance was zeroed and connected to the computer for data output. The moving platform was controlled to move upward until the liquid-absorbing core structure was submerged 1-2mm below the liquid surface. After the data showed no significant fluctuations, the platform was controlled to separate the liquid-absorbing core from the beaker.

[0078] Analyze and process the data recorded by the computer:

[0079] Comparing (1) and (2), it can be found that the capillary aspiration rate of (2) is 35% higher than that of (1), proving that the bilayer structure has a higher capillary aspiration rate than the monolayer structure, and the liquid absorption volume can be increased by 20%-40%.

[0080] Comparing (3) and (4), it can be found that the capillary suction core with internal support columns has a double-layer structure that increases the capillary suction rate by 27% compared to the single-layer structure. Secondly, comparing (3) and (1), the support column structure of (3) has a greater advantage in space ratio, which increases its capillary suction rate by 25% compared to (1) without support columns, and increases the suction rate by about 30%.

[0081] Comparing (5) and (3), it can be found that as the height of the aspirator structure unit increases, its capillary aspiration rate increases. For every 50 μm increase in unit height, the aspirator aspiration rate will increase by 5%. Secondly, compared with (3), the diameter of the internal support column in (5) is doubled, and the frameless design of the inner layer increases the space ratio of the support column. In comparison, the capillary aspiration rate will increase by 25%-35%.

[0082] The structure (5) was designed as a double-layer structure (6), and the suction rate of the double-layer structure was increased by 35% again. Due to the double-layer, thick support column and no inner frame design of (6), the suction rate of this design is the best among the eight designs, and the liquid absorption volume is also the highest.

[0083] Data analysis showed that the capillary suction rate of the (8) double-layer structure was 23% higher than that of the (7) single-layer structure. Compared with the previous large-size structure, the capillary suction rate of the double-layer structure decreased by 38% due to the reduction in the diameter of the support column. This proves that the higher space ratio of the support column will enable the liquid suction core unit to obtain a faster suction rate and liquid volume.

[0084] The capillary suction curves of the eight customized capillary core structures prepared are as follows: Figure 10 As shown, from Figure 10 It can be seen that the double-layer, frameless, body-centered cubic liquid-absorbing core assembly structure has the highest liquid absorption capacity and the corresponding capillary suction curves of other structures. Through... Figure 10 The curve was transformed to obtain the data. Figure 11 A comparison chart of capillary suction rates for eight different structures, from Figure 11 As can be seen, the double-layer frameless body-centered cubic liquid-absorbing core combination unit structure with the highest liquid absorption capacity also has the highest capillary suction rate.

[0085] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for designing capillary wick structures, characterized in that, The capillary liquid-absorbing core structure includes two or more layer structures, which are stacked one on top of the other; each layer structure includes multiple units arranged in an array; each unit includes multiple interconnected support pillars, and the surface of the support pillars is coated with a hydrophilic coating. The method for designing a capillary wick structure includes the following steps: Based on the heat dissipation requirements of specific electronic devices, the liquid absorption volume V0 and liquid absorption speed U0 of the capillary wick structure are set, and the diameter of the support column, the length, width and height of the unit, and the number of layers of the layer structure are designed. The designed capillary wick structure was fabricated using 3D printing, and a coating was prepared and a hydrophilic treatment was completed. The performance of the obtained capillary core structure was tested to obtain the liquid absorption volume V1 and the liquid absorption speed U1. Determine whether V1 is greater than or equal to V0 and whether U1 is greater than or equal to U0. If the conditions are met, the designed capillary liquid absorption core structure meets the standard. If the conditions are not met, continue to optimize the diameter of the support column, the length, width and height of the unit or the number of layers in the layer structure, and carry out preparation and testing until the conditions are met.

2. The method for designing a capillary wick structure according to claim 1, characterized in that, The thickness of the capillary wick structure is 0.1mm-1mm, and the length and width of the capillary wick structure are independently 10mm-100mm.

3. The method for designing a capillary wick structure according to claim 2, characterized in that, The overall length and width of the unit are each 450-550 μm, and the overall height of the unit is 100-1000 μm.

4. The method for designing a capillary wick structure according to claim 3, characterized in that, The diameter of the support column is 30-100μm.

5. The method for designing a capillary wick structure according to claim 1, characterized in that, The unit's multiple support columns are cross-connected to form a body-centered cubic structure or a face-centered cubic structure.

6. The method for designing a capillary wick structure according to claim 1, characterized in that, The bottom and top of the capillary absorbent core structure are provided with a border around the outer ring of each unit.

7. The method for designing a capillary wick structure according to claim 1, characterized in that, The fabrication of the designed capillary wick structure using 3D printing includes the following steps: After integrating slices through 3D modeling, a capillary wick structure is initially obtained by photopolymerization printing. Then, a coating is made on the surface of the capillary wick structure and the coating is hydrophilic.

8. The method for designing a capillary wick structure according to claim 7, characterized in that, The coating preparation includes the following steps: First, the surface of the capillary wick structure is roughened using chromic acid, then sensitized using a sensitizer, and after sensitization, it is activated using an activator. After that, the treated capillary wick structure is placed in a chemical copper / nickel plating solution at 40°C for 40-50 minutes and then removed to complete the copper / nickel plating.

9. The method for designing a capillary wick structure according to claim 8, characterized in that, The hydrophilic treatment involves soaking the affected area in a hydrogen peroxide solution for 3-5 minutes.

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