Liquid-absorbent wick, its manufacturing method, and vapor chamber

Abstract

The present invention discloses a liquid-absorbent wick, a manufacturing method thereof, and a vapor chamber. The liquid-absorbent wick is attached to a shell, which has a cover plate. The liquid-absorbent wick has a first bypass groove and a second bypass groove, respectively. The first bypass groove is used together with the cover plate to form a first capillary, and the first capillary and second bypass grooves are used to connect a heat source region and a heat dissipation region. The first bypass groove has a capillary hole through which a working fluid and its vapor pass. The gas-liquid interface formed in the first capillary and the second bypass groove serves as a phase transition interface, providing an evaporation interface at the heat absorption end and a condensation interface at the heat dissipation end, generating capillary pressure to drive the condensed working fluid back to the heat source region. Compared to the prior art, the technical solution of the present invention can increase the capillary pressure and the reflux rate of the working fluid to the heat source region, thereby improving the heat conduction capacity of the vapor chamber. By adjusting the size of the capillary hole and the first capillary, high capillary pressure and high flow rate can be simultaneously achieved.

Description

[Technical Field]

[0001] The present invention relates to the technical field of heat dissipation devices, and in particular to a liquid absorbent wick and its manufacturing method, and a vapor chamber. [Background technology]

[0002] A vapor chamber is a commonly used heat-conducting component that includes a shell, an absorbent wick, and a working fluid. A chamber is formed inside the shell, and the absorbent wick and working fluid are located within the chamber. When the vapor chamber is in use, the cover plate of the shell contacts a heat source. The area of ​​the vapor chamber facing the heat source is the heat source area, and a heat dissipation area is installed outside the heat source area. The absorbent wick can have various structures, such as silk mesh, sintered copper powder, micro-column array, grooves, and metal foam, and has capillary properties that allow it to absorb working fluid.

[0003] When the vapor chamber is operating, the working fluid in the heat source area is heated and vaporizes, and the vapor overflows from the absorbent wick and flows into the vapor chamber of the shell. After the vapor leaves the heat source area, it condenses and releases heat, turning back into a liquid, which then flows back to the heat source area under the action of the absorbent wick. The above evaporation heat absorption and condensation heat release processes are carried out in a cyclical manner, transferring part of the heat in the heat source area to the heat release area, reducing the temperature difference between the heat source area and the heat release area, achieving the effect of temperature equalization.

[0004] In the prior art, the capillary pressure of the absorbent wick is limited or uncontrollable, limiting the working length and thermal conductivity of the vapor chamber, especially in the case of resistance acceleration. The limited capillary pressure results in a rapid drop in thermal conductivity and even malfunction. For example, in the currently commonly used silk mesh and foam absorbent wicks, when the working fluid flows over them, the capillary force is generated from the wool structure formed between the silk or between the silk and the shell plate, resulting in low capillary capacity, or the flow path is due to the irregular porous structure of the absorbent wick itself, resulting in a twisted internal flow path, high liquid flow resistance, and many ineffective paths. Some conventional tightly woven silk stripe or fiber structures have strong capillary force, but often have low porosity, high flow resistance, and low capillary flow. In recent years, absorbent wicks with grooved or near-grooved structures have also been widely researched and developed, primarily due to the processability of these materials. However, the grooved structure has open fluid channels, resulting in low capillary force, slowing the flow of working fluid and reducing capillary flow, which reduces the heat conduction capacity of the vapor chamber. Therefore, a good absorbent wick must simultaneously possess the advantages of high capillary force and large capillary flow, thereby accelerating the cycle of working fluid and improving the thermal conductivity of the vapor chamber. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide an absorbent wick, a manufacturing method thereof, and a vapor chamber for increasing the reflux rate of the working fluid to the heat source area, thereby improving the cooling capacity of the vapor chamber.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention discloses a liquid absorbent wick, which is used to attach to a shell, the shell having a cover plate, the liquid absorbent wick having a first bypass groove, the first bypass groove being used to form a first capillary together with the cover plate; The first capillary tube is used to connect the heat source region and the heat dissipation region, so that the working fluid condensed in the heat dissipation region can return to the heat source region through the first capillary tube under the action of capillary pressure.

[0008] Preferably, the shell has a vapor chamber located on one side of the absorbent wick away from the cover plate, and the absorbent wick has capillary holes formed therein, which are used to connect the first bypass groove and the vapor chamber, thereby allowing the working fluid and its vapor to flow between the first bypass groove and the vapor chamber.

[0009] Preferably, the absorbent wick also has a second bypass groove located on one side of the absorbent wick closer to the steam chamber, and the second bypass groove is used to connect the heat source area and the heat dissipation area, so that working fluid condensed in the heat dissipation area can return to the heat source area via the second bypass groove under the action of capillary pressure.

[0010] Preferably, a first end of the first capillary is used to be positioned in the heat source area, and a second end of the first capillary is used to be positioned in the heat dissipation area, and the effective capillary radius of the capillary hole positioned in the first end of the first capillary is smaller than the effective capillary radius of the capillary hole positioned in the second end of the first capillary, thereby increasing the capillary pressure that causes the working fluid to return to the heat source area.

[0011] Preferably, the absorbent wick also has a connecting channel and includes a plurality of the first capillaries, and two adjacent first capillaries communicate with each other via the connecting channel, thereby allowing the working liquid and vapor of the working liquid to flow between different first capillaries.

[0012] Preferably, the connecting channel includes a connecting groove, which is used to form a second capillary together with the cover plate.

[0013] The present invention also discloses a vapor chamber, comprising the above-mentioned absorbent wick and the shell, wherein the shell has the cover plate, one side of the cover plate is used for contacting a heat source, and the other side of the cover plate forms the first capillary together with the first bypass groove.

[0014] Preferably, the shell has a vapor chamber located on one side of the absorbent wick away from the cover plate, and the absorbent wick has capillary holes formed therein, which are used to connect the first bypass groove and the vapor chamber, thereby allowing the working fluid and its vapor to flow between the first bypass groove and the vapor chamber.

[0015] The present invention also discloses a method for producing the above-mentioned absorbent wick, Step S1: arranging a stripe structure on a surface of a base to obtain a substrate, and the side of the substrate on which the stripe structure is located is a deposition surface; Step S2: depositing a metal layer on the deposition surface of the substrate, the metal layer covering at least a portion of the deposition surface, the material of the metal layer being different from both the material of the stripe structure and the material of the base; Step S3 includes removing the base and the stripe structure, and forming the first bypass groove after removing the stripe structure.

[0016] Preferably, the method for producing the liquid absorbent wick comprises: The method further includes a step S4 of processing capillary holes in the first bypass groove. [Effects of the Invention]

[0017] Compared with the prior art, the present invention achieves the following technical advantages: The first bypass groove of the absorbent wick is used to form a first capillary tube with the cover plate. The first capillary tube has a pipe structure with a specific direction, and the cross section of the pipe structure may be rectangular, trapezoidal, semicircular, major arc-shaped, minor arc-shaped, or similar shapes. Compared with the prior art, such as a grooved structure or an open structure (including silk mesh, sintered copper powder, and foam structure), the working fluid in the present invention flows along the first capillary tube rather than along a path with internal clogs when returning from the heat dissipation area to the heat source area. This reduces the flow resistance of the working fluid and shortens the flow time, thereby improving the return speed of the working fluid to the heat source area and further improving the heat conduction capacity.

[0018] In a preferred solution of the present invention, a capillary hole is installed in the first capillary, so that the gas-liquid interface in the first capillary and the second bypass groove together provide capillary pressure, thereby increasing the capillary pressure difference between the heat source area and the heat dissipation area, improving the reflux rate of the working fluid to the heat source area, and further improving the heat conduction capacity. By adjusting the size of the capillary hole and the first capillary, high capillary pressure and large flow rate can be achieved simultaneously, eliminating the disadvantages of the conventional solution, such as randomness and difficulty in adjusting the capillary pressure and working fluid flow rate.

[0019] In a preferred solution of the present invention, the effective capillary radius of the capillary holes in the heat source region is smaller than that of the capillary holes in the heat dissipation region, thereby further increasing the capillary pressure that causes the working fluid to return to the heat source region.

[0020] The vapor chamber and the manufacturing method of the absorbent wick of the present invention all have the technical effects corresponding to the absorbent wick, and will not be further described here. [Brief explanation of the drawings]

[0021] In order to more clearly describe the embodiments of the present invention or the technical solutions in the prior art, the drawings necessary to be used in the embodiments will be briefly described below. Obviously, the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can also obtain other drawings based on these drawings without any creative efforts.

[0022] [Figure 1] 3 is a schematic diagram showing the connection relationship between the absorbent wick and the cover plate according to an embodiment of the present invention. FIG. [Figure 2] 10 is another schematic diagram of the connection relationship between the absorbent wick and the cover plate according to an embodiment of the present invention. FIG. [Figure 3] 10 is another schematic diagram of the connection relationship between the absorbent wick and the cover plate according to an embodiment of the present invention. FIG. [Figure 4] 10 is another schematic diagram of the connection relationship between the absorbent wick and the cover plate according to an embodiment of the present invention. FIG. [Figure 5] 10 is another schematic diagram of the connection relationship between the absorbent wick and the cover plate according to an embodiment of the present invention. FIG. [Figure 6] 10 is another schematic diagram of the connection relationship between the absorbent wick and the cover plate according to an embodiment of the present invention. FIG. [Figure 7] 1 is a schematic top view of an absorbent wick according to an embodiment of the present invention. [Figure 8] 3 is another schematic top view of an absorbent wick according to an embodiment of the present invention. FIG. [Figure 9] 3 is another schematic top view of an absorbent wick according to an embodiment of the present invention. FIG. [Figure 10] 3 is another schematic top view of an absorbent wick according to an embodiment of the present invention. FIG. [Figure 11] 3 is another schematic top view of an absorbent wick according to an embodiment of the present invention. FIG. [Figure 12] 3 is another schematic top view of an absorbent wick according to an embodiment of the present invention. FIG. [Figure 13] 3 is another schematic top view of an absorbent wick according to an embodiment of the present invention. FIG. [Figure 14] 1 is another schematic top view of an absorbent wick according to an embodiment of the present invention; [Figure 15] 1 is a schematic diagram showing the arrangement of an absorbent wick according to an embodiment of the present invention. [Figure 16] 3 is a schematic diagram showing another arrangement of the absorbent wick according to an embodiment of the present invention. FIG. [Figure 17] 1 is a cross-sectional schematic diagram illustrating the placement of an absorbent wick in a single-sided shell of a steam chamber according to an embodiment of the present invention. [Figure 18] 10 is a cross-sectional schematic diagram of another arrangement of an absorbent wick in a single-sided shell of a steam chamber according to an embodiment of the present invention. [Figure 19] 1 is a cross-sectional schematic diagram illustrating the arrangement of an absorbent wick in a double-sided shell of a steam chamber according to an embodiment of the present invention. [Figure 20] 1 is a cross-sectional schematic view of a first capillary of an absorbent wick according to an embodiment of the present invention, transporting hydraulic fluid. [Figure 21] 1 is a cross-sectional schematic view of a liquid absorbent wick according to an embodiment of the present invention, in which a first capillary and a second bypass groove simultaneously transport hydraulic fluid. [Figure 22] 1 is a cross-sectional schematic diagram of an absorbent wick according to an embodiment of the present invention transporting hydraulic fluid in an evaporation region. [Figure 23] 1 is a cross-sectional schematic diagram of an absorbent wick according to an embodiment of the present invention transporting hydraulic fluid in a condensation region. [Figure 24] 1 is an exploded schematic view of a vapor chamber according to an embodiment of the present invention. [Figure 25] 1 is a schematic diagram of Example 1 of a method for manufacturing a liquid absorbent wick according to an embodiment of the present invention. [Figure 26] FIG. 2 is a schematic diagram showing Example 2 of a method for manufacturing a liquid-absorbent wick according to an embodiment of the present invention. [Figure 27] FIG. 3 is a schematic diagram showing Example 3 of a method for manufacturing a liquid-absorbent wick according to an embodiment of the present invention. [Figure 28] 1 shows wicking performance test data of absorbent wicks according to examples of the present invention and a comparison with commercial silk mesh materials. DETAILED DESCRIPTION OF THE INVENTION

[0023] The following provides a clear and complete description of the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some of the embodiments of the present invention, and not all of the embodiments, and all other embodiments obtained by those skilled in the art without any creative efforts based on the embodiments of the present invention are all within the scope of protection of the present invention.

[0024] The present invention aims to provide an absorbent wick, a manufacturing method thereof, and a vapor chamber for improving the reflux rate of the working fluid to the heat source area, thereby improving the thermal conductivity of the vapor chamber.

[0025] In order to make the above objects, features and advantages of the present invention clearer and more comprehensible, the present invention will be described in more detail below with reference to the drawings and specific embodiments.

[0026] 1 to 23, this embodiment provides a liquid-absorbent wick 200, which is used to attach to the shell of a vapor chamber 100, and the shell has a cover plate. The liquid-absorbent wick 200 has a first bypass groove, which is used to form a first capillary 210 together with the cover plate, and the cover plate and the liquid-absorbent wick 200 can be fixed and connected by a sintering method.

[0027] The first capillary tube 210 is used to connect the heat source region 400 (also called the evaporation region) and the heat dissipation region 420 (also called the condensation region), so that the working fluid 300 condensed in the heat dissipation region 420 can be returned to the heat source region 400 through the first capillary tube 210 under the action of capillary pressure.

[0028] FIGS. 7 to 14 provide top schematic views of various examples of the liquid absorbent wick 200 according to this embodiment. When there are multiple first bypass grooves, the first bypass grooves may be linear (see FIGS. 7, 8, and 11). In FIGS. 7 and 8, the multiple first bypass grooves are parallel to each other. The first bypass grooves may also be curved (see FIGS. 9, 10, 12, 13, and 14). In FIGS. 11, 12, and 13, the multiple first bypass grooves are radially distributed. Referring to FIG. 14, the first bypass grooves may be designed as a branched structure along the flow direction, thereby increasing the contact area of ​​the condensation section and better collecting and returning the condensed working fluid 300. However, actual embodiments are not limited thereto. The channel network shape can be flexibly designed according to the heat conduction needs of the vapor chamber design to achieve the objectives of the present invention.

[0029] 17 to 19 provide examples of cross-sectional shapes of the liquid absorbent wick 200 according to this embodiment. The cross-section of the first bypass groove may have a variety of shapes, such as a semicircle (see FIG. 17), a square (see FIGS. 18 and 19), an arcuate shape, a trapezoidal shape, a triangular shape, etc., which can be selected by those skilled in the art according to actual needs.

[0030] In the example corresponding to FIGS. 18 and 19, the cross section of the first capillary 210 is rectangular, its width is 10 microns to 2 mm, and its height is 1 micron to 500 microns.

[0031] The working principle of the liquid absorbent wick 200 according to this embodiment is as follows.

[0032] The first bypass groove of the absorbent wick 200 is used to form the cover plate and the first capillary 210, which is a pipe structure with a specific direction. Compared to the prior art, in this embodiment, the working fluid 300 flows along the first capillary 210 while returning from the heat dissipation area 420 to the heat source area 400, and there is no blockage inside, so the flow resistance of the working fluid 300 is smaller and the flow is shorter, which effectively improves the return speed of the working fluid 300 to the heat source area 400 and further improves the heat conduction capacity.

[0033] The shell of the vapor chamber 100 is generally a sealed structure, and its cover plates include a second cover plate 102 and a second cover plate 101 positioned opposite each other, and the second cover plate 102 and the second cover plate 101 are connected via a plurality of side plates. The liquid absorbent wick 200 is located between the second cover plate 102 and the second cover plate 101. The liquid absorbent wick 200 can be arranged in two ways: (1) One side of the absorbent wick 200 is connected to the second cover plate 102, and the other side is connected to the second cover plate 101. At this time, there is a first capillary 210 (such a form is not shown) between the second cover plate 102 and the absorbent wick 200 and between the second cover plate 101 and the absorbent wick 200. (2) One side of the liquid absorbent wick 200 is connected to the second cover plate 102 or the second cover plate 101, and the other side of the liquid absorbent wick 200 is the steam chamber 103 (see Figures 17 to 24). The liquid absorbent wick 200 may be disposed on both the second cover plate 102 and the second cover plate 101 (see Figure 19), or the liquid absorbent wick 200 may be disposed on only one of the second cover plate 102 and the second cover plate 101 (see Figures 17 to 18, 20 to 24).

[0034] As a possible example, in the second arrangement of the absorbent wick 200, the absorbent wick 200 is provided with capillary holes 250 for connecting the first bypass groove and the vapor chamber 103, thereby allowing the working fluid 300 and its vapor to flow between the first bypass groove and the vapor chamber 103. In the heat source region 400, the capillary holes 250 provide an evaporation interface, and in the heat dissipation region 420, the capillary holes 250 provide a condensation interface.

[0035] The shape and arrangement of the capillary holes 250 can be flexibly selected and are described below only by way of example. If the capillary holes 250 are large, they can penetrate the first bypass groove (see FIGS. 4 and 6). In this case, the width of the capillary holes 250 should not be too large to prevent capillary flow from being blocked; the width of the capillary holes 250 is controlled to be less than several hundred microns, such as 1 micron, 10 microns, 50 microns, 100 microns, or 200 microns. If the capillary holes 250 are small, they can be located only at the bottom of the first bypass groove (not penetrating the first bypass groove), see FIGS. 3 and 5. The capillary hole 250 in Figures 4 and 6 is striped, and the angle between the length direction of the capillary hole 250 and the length direction of the first bypass groove in Figure 4 is an acute angle α, and the angle between the length direction of the capillary hole 250 and the length direction of the first bypass groove in Figure 6 is a right angle. The capillary hole 250 in Figure 3 is circular or elliptical, and the capillary hole 250 in Figure 5 is rectangular.

[0036] The formation of the capillary holes 250 can be completed by methods such as laser processing, chemical etching processing, ion etching processing (RIE, DRIE), electrochemical processing, or mechanical processing. Illustratively, the shape of the capillary holes 250 may be circular, elliptical, arc-shaped, triangular, square, trapezoidal, star-shaped, strip-shaped, or a combination thereof. The minimum size of the capillary holes 250 is determined by the required capillary pressure, and this size can vary from a few nanometers to a few millimeters.

[0037] As a possible example, referring to FIGS. 1 and 3 to 6, the liquid absorbent wick 200 also has a second bypass groove 220 located on one side of the liquid absorbent wick 200 closer to the vapor chamber 103. The second bypass groove 220 is used to connect the heat source region 400 and the heat dissipation region 420, allowing the working liquid 300 condensed in the heat dissipation region 420 to return to the heat source region 400 via the second bypass groove 220 under the action of capillary pressure. Compared to the first capillary tube 210, the second bypass groove 220 does not form a complete pipe structure. Therefore, the capillary pressure is smaller and the second bypass groove 220 serves as an auxiliary channel for the working liquid 300. Referring to FIG. 14, the first and second bypass grooves 220 can be designed to have different widths along the flow direction of the working liquid 300 depending on the shape of the vapor chamber, which is used to adjust the gas-liquid contact area and capillary force.

[0038] Depending on the heat dissipation needs, the size and spacing of the first and second bypass grooves 220 of different liquid absorbent wicks 200 can be adjusted, and they can also be adjusted to different positions on the same liquid absorbent wick 200. The width W1, spacing W2 and height H1 of the capillaries of the liquid absorbent wicks 200 in Figures 17 and 18 can vary from a few nanometers to thousands of microns, such as 10 nanometers, 100 nanometers, 1 micron, 10 microns, 50 microns, 100 microns, 200 microns, 500 microns, 1000 microns, etc.

[0039] 2, 8 and 10, the absorbent wick 200 also has a connecting channel 230. It includes a plurality of first capillaries 210, and two adjacent first capillaries 210 communicate with each other via the connecting channel 230, thereby allowing the working liquid 300 and vapor of the working liquid 300 to flow between different first capillaries 210. By connecting adjacent first capillaries 210 via the connecting channel 230, a mesh structure can be formed, which is beneficial for balanced distribution and rapid flow of the working liquid 300.

[0040] 2, the connecting channel 230 includes a connecting groove, which is used to form the second capillary together with the cover plate. It can be understood that the connecting channel 230 can also include a connecting hole. In this example, the second capillary is rectangular, and its size can vary from a few nanometers to thousands of microns, for example, 10 nanometers, 100 nanometers, 1 micron, 10 microns, 50 microns, 100 microns, 200 microns, 500 microns, 1000 microns, etc., with reference to the previous selection of the capillary width W1 and height H1.

[0041] 15, the liquid absorbent wick 200 is connected to a heat source region 400, a heat insulating region 410, and a heat dissipation region 420. The liquid absorbent wick 200 has capillary holes 250 arranged in the heat source region 400 and the heat dissipation region 420, and the shape of the capillary holes 250 can be any of the shapes described above or a combination thereof. The working fluid 300 condensed in the heat dissipation region 420 flows back to the heat source region 400 under the action of capillary pressure through the first capillary tubes 210 corresponding to the liquid absorbent wick 200 and the second bypass grooves 220 of the liquid absorbent wick 200.

[0042] 16, the liquid absorbent wick 200 is connected to the heat source region 400 and the heat dissipation region 420, with no heat insulating region 410 in between. The liquid absorbent wick 200 has capillary holes 250 arranged in the heat source region 400 and the heat dissipation region 420, and the capillary holes 250 may be circular, elliptical, arc-shaped, triangular, rectangular, trapezoidal, star-shaped, strip-shaped, or a combination thereof. The first capillary tubes 210 corresponding to the liquid absorbent wick 200 and the second bypass grooves 220 of the liquid absorbent wick 200 allow the working fluid 300 condensed in the heat dissipation region 420 to directly return to the heat source region 400 under the action of capillary pressure.

[0043] When no vapor is present, the first capillary tube 210 of the absorbent wick 200 is full of working liquid 300 (as shown in FIG. 20A). When vapor is present, the first capillary tube 210 is partially filled with working liquid 300 (as shown in FIG. 20B).

[0044] In the case of an example (abbreviated as Example A) in which the liquid absorbent wick 200 simultaneously has the first detour groove, the second detour groove 220, and the capillary holes 250, In the heat source region 400 and the heat dissipation region 420, the working liquid 300 in the first capillary 210 enters the second bypass groove 220 (shown in FIG. 21A), and the first capillary 210 and the second bypass groove 220 simultaneously transport the working liquid 300, and a second gas-liquid interface 310 exists in the second bypass groove 220. FIG. 21B shows a flow situation in which the working liquid 300 is full when some vapor enters a certain portion of the first capillary 210, and a gas-liquid interface exists simultaneously in the first capillary 210 and the second bypass groove 220.

[0045] In the liquid absorbent wick 200 (shown in FIG. 22) in the heat source region 400, a capillary through-hole 250 is arranged in the first capillary 210, and the working liquid 300 is simultaneously present in the first capillary 210 and the second bypass groove 220, and a first gas-liquid interface 320 is present in the first capillary 210, and a second gas-liquid interface 310 is present in the second bypass groove 220, and the gas-liquid interface provides capillary pressure.

[0046] In the liquid absorbent wick 200 (shown in FIG. 23) in the heat dissipation region 420, a capillary through-hole 250 is arranged in its first capillary 210, and the working liquid 300 is simultaneously present in the first capillary 210 and the second bypass groove 220, and a first gas-liquid interface 320 is present in the first capillary 210, and a second gas-liquid interface 310 is present in the second bypass groove 220, and the gas-liquid interface provides capillary pressure.

[0047] The second gas-liquid interface 310 of the second bypass groove 220 in the heat source region 400 and the heat dissipation region 420 generates different capillary pressures due to the evaporation and condensation processes and different adjustments of the size of the capillary holes 250, ultimately forming a capillary pressure difference at both ends to drive the working fluid 300 to return from the second bypass groove 220.

[0048] In the case of Example A above, the working principle is as follows: In Example A, one of the core working principles of the absorbent wick 200 is to increase the pressure difference by adjusting the arrangement and size of the capillary holes 250. The capillary holes 250 are arranged in the first capillary tube 210 (FIGS. 22 and 23), and are connected to the vapor chamber 103 via the first gas-liquid interface 320, allowing the working liquid 300 and its vapor to flow between them. The first gas-liquid interface 320 in the heat source region 400 and the heat dissipation region 420 forms different radii of curvature of the gas-liquid interface due to the evaporation and condensation processes and the different adjustments of the size of the capillary holes 250, thereby generating different capillary pressures. This ultimately creates a capillary pressure difference between the heat source region 400 and the heat dissipation region 420, driving the working liquid 300 to flow back from the heat dissipation region 420 to the heat source region 400.

[0049] In Example A, the second bypass groove 220 serves as an auxiliary channel for transporting the working liquid 300. In the heat source region 400, the first gas-liquid interface 320 not only provides an evaporation interface, but also the second gas-liquid interface 310. In the heat dissipation region 420, the first gas-liquid interface 320 not only provides a condensation interface, but also the second gas-liquid interface 310. The second gas-liquid interfaces 310 of the second bypass groove 220 in the heat source region 400 and the heat dissipation region 420 generate different capillary pressures due to the evaporation and condensation processes and the different sizes of the capillary holes 250, ultimately forming a capillary pressure difference between the two ends and driving the working liquid 300 to return from the second bypass groove 220. Compared to the first capillary 210, the second bypass groove 220 does not form a complete pipe structure, so the capillary pressure is smaller.

[0050] In a preferred example, the first end of the first capillary 210 is used to be positioned in the heat source region 400, and the second end of the first capillary 210 is used to be positioned in the heat dissipation region 420. The effective capillary radius of the capillary hole 250 positioned in the first end of the first capillary 210 is smaller than the effective capillary radius of the capillary hole 250 positioned in the second end of the first capillary 210, thereby increasing the capillary pressure that causes the working fluid to return to the heat source region. For ease of understanding, the principle will be explained below.

[0051] For a capillary tube of length L, hydraulic radius R, and cross-sectional area A, its flow rate Q is described by the following equation: TIFF2025537444000002.tif37170Here, a is a dimensionless coefficient related to the cross-sectional shape of the capillary, μ is the fluid power viscosity coefficient, and ΔP is the pressure difference across the capillary. For a circular pipe with radius R, TIFF2025537444000003.tif102126For a rectangular cross-section pipe with base width W and height h=βW, TIFF2025537444000004.tif54170

[0052] As can be seen from equation (1), increasing the cross-sectional size of the capillary and the pressure difference across it can increase the capillary flow rate. If the effect of gravity is neglected, TIFF2025537444000005.tif37170 where ΔP ce and ΔP cc are the capillary pressures generated by the capillary holes 250 at the evaporation end (the first end of the first capillary tube 210 in Corresponding Example A) and the condensation end (the second end of the first capillary tube 210 in Corresponding Example A), respectively, and the effective capillary radius r e and the effective capillary radius r of the capillary hole 250 at the condensation end c It can be expressed as: TIFF2025537444000006.tif37170TIFF2025537444000007.tif37170where σ is the surface tension coefficient and θ e and θ c are the contact angles at the evaporation end and condensation end, respectively. Substituting into equation (2), the pressure difference between the two ends is It can be TIFF2025537444000008.tif22170.

[0053] As can be seen from equation (5), for a constant contact angle, the pressure difference can be increased by adjusting the effective radius of the capillary holes 250, e.g., by decreasing the effective radius of the holes and increasing r e <r cor a combination thereof.

[0054] Two of the core operating principles of Example A are the size adjustment of the first capillary 210. Under a given capillary pressure, the cross-sectional size of the first capillary 210 determines the capillary flow rate; increasing the cross-sectional size increases the flow rate. This resolves the contradiction of conventional small-diameter capillaries or capillary grooves, which have high capillary pressure but high flow resistance and low flow rate. Compared to the prior art, Example A's working fluid 300 experiences higher capillary pressure and lower flow resistance as it flows back from the heat dissipation region 420 to the heat source region 400 along the first capillary 210 and the second bypass groove 220. This effectively improves the return rate of the working fluid 300 to the heat source region 400 and further enhances heat dissipation capacity.

[0055] 24, this embodiment further provides a vapor chamber 100, which includes an absorbent wick 200 and a shell. The absorbent wick 200 has the above-mentioned first bypass groove. The shell has a cover plate, one side of which is used to contact a heat source, and the other side of which forms a first capillary 210 together with the first bypass groove.

[0056] The vapor chamber 100 according to this embodiment includes the above-mentioned absorbent wick 200, and therefore also has the above-mentioned advantages of the absorbent wick 200, which will not be further described here.

[0057] As a possible example, referring to Figure 24, the shell has a vapor chamber 103 located on one side of the absorbent wick 200 away from the cover plate. The absorbent wick 200 has a through-hole connecting the first bypass groove and the vapor chamber 103, allowing the working liquid 300 and its vapor to flow between the first bypass groove and the vapor chamber 103.

[0058] Referring to Figure 24, the shell generally has a second cover plate 102 and a second cover plate 101, the second cover plate 102 and the second cover plate 101 are connected via some side plates, and the liquid absorbent wick 200 is located between the second cover plate 102 and the second cover plate 101. The liquid absorbent wick 200 is fixed to the second cover plate 102, and the vapor chamber 103 is located between the liquid absorbent wick 200 and the second cover plate 101. For clarity, Figure 24 omits the side plates of the shell and only shows the cover plates of the shell.

[0059] As a possible example, referring to FIG. 24, the vapor chamber 100 also includes a support member 104, which (all or part) is located within the vapor chamber 103, thereby limiting the minimum height of the vapor chamber 103. When the support member 104 is entirely within the vapor chamber 103, the upper end of the support member 104 abuts the absorbent wick 200, and the lower end of the support member 104 abuts the lower cover plate. When only part of the support member 104 is within the vapor chamber 103, the support member 104 penetrates the absorbent wick 200, and both ends of the support member 104 abut against the two cover plates, respectively. By installing the support member 104, it is possible to prevent the vapor chamber 103 from sinking.

[0060] This embodiment also provides a method for manufacturing the above-mentioned absorbent wick 200, which, with reference to FIGS. 25, 26 and 27, includes the following steps: S1, mold manufacturing: A stripe structure 201a is arranged on the surface of a base 202 to obtain a mold substrate. The material of the base 202 may be an inorganic material (e.g., copper, aluminum, nickel, zinc, tin, gold, iron, cobalt, cadmium, chromium, tin, silver, titanium, palladium, etc., or alloys such as stainless steel, zinc-nickel, zinc-copper, zinc-iron, nickel-iron, nickel-cobalt, copper-tin, zinc-nickel-iron, tin-zinc-antimony, zinc-tin-iron, and tin-zinc-cobalt), or an organic material (e.g., ABS: acrylonitrile-butadiene-styrene, EVA: ethylene-vinyl acetate polymer, EPS: polystyrene, HDPE: high-density polyethylene, LDPE: low-density polyethylene, PI: polyimide, PET: polyester, PE: polyethylene, PP: polypropylene, PC: polycarbonate, PVC: vinyl chloride, PU: polyurethane, PMMA: polymethyl methacrylate, PS: polystyrene, PDMS: polydimethylsiloxane, PPS: polystyrene sulfur ether, Teflon: Teflon (registered trademark), Nylon: nylon, PEEK: polyether ether ketone), or a mixed material (e.g., a mixture of organic materials, a mixture of inorganic materials, or a mixture of organic and inorganic materials).

[0061] The stripe structure 201a can be fabricated using methods such as photolithography (e.g., soft lithography, laser ablation), printing (2D and 3D printing, wax printing), printing (e.g., screen printing), spraying (including cold spraying and hot spraying), etching, and machining. Soft lithography is a common microfabrication method and will not be described in detail here. For the printing method, a slurry must first be prepared, and then printed onto a base using a printing method to obtain a mold substrate. Depending on the technical route, the main material of the slurry can be a photosensitive material or a metal particle-based material. Depending on the capillary manufacturing method, the mold substrate may need to undergo the above-mentioned pretreatment on its surface, such as making it conductive.

[0062] S2, Capillary tube fabrication: A metal layer 199 is deposited on the substrate, and the metal layer 199 covers the striped structure 201a and at least a portion of the surface where the striped structure 201a is located. The material of the metal layer 199 is different from that of the striped structure 201a and the base 202. The base 202 and the striped structure 201a are removed to obtain an independent liquid-absorbent wick 200. The liquid-absorbent wick 200 has a first bypass groove, which is formed after the striped structure 201a is removed.

[0063] The material of the metal layer 199 is preferably copper, aluminum, nickel, zinc, tin, gold, iron, cobalt, cadmium, chromium, tin, silver, titanium, palladium, etc., or an alloy such as stainless steel, zinc-nickel, zinc-copper, zinc-iron, nickel-iron, nickel-cobalt, copper-tin, zinc-nickel-iron, tin-zinc-antimony, zinc-tin-iron, or tin-zinc-cobalt.

[0064] S3, Fabrication of 250 capillary holes: The capillary holes 250 are formed in the absorbent wick 200, and the formation of the capillary holes 250 can be completed by laser processing, chemical etching processing, etching processing (e.g., ICP, RIE, DRIE), electrochemical processing, mechanical processing, etc. The shape of the capillary holes 250 can be circular, elliptical, arc-shaped, triangular, rectangular, trapezoidal, star-shaped, strip-shaped, etc., or a combination thereof.

[0065] As a possible example, the materials of the stripe structure 201a and the base 202 may be the same or different. The materials of the stripe structure 201a and the base 202 can be removed by methods such as corrosion removal, melting (e.g., polymer materials such as PC (polycarbonate), PU (polyurethane), and PDMS (polydimethylsiloxane)), or corrosion removal and peeling (e.g., mixed materials, mixtures of metal and polymer materials, or salts and polymer materials). The material of the metal layer 199 is preferably copper, aluminum, nickel, zinc, tin, etc., and the deposition method can be PVD (physical vapor deposition), electroplating, etc.

[0066] As a possible example, the thickness of the metal layer can be determined by the size of the vapor chamber, and this thickness can vary between a few nanometers and several millimeters, but typical application thicknesses are all controlled between 1 and 50 microns.

[0067] As a possible example, the size (e.g., radius or length) of the capillary holes 250 can be determined depending on the heat dissipation requirements of the vapor chamber, the speed requirements of the capillary circulation of the working liquid, and the working conditions (e.g., the influence of gravity or other acceleration effects), and this size can vary between a few nanometers and a few millimeters, but the general application sizes are all controlled between microns and hundreds of microns.

[0068] The method for manufacturing the liquid absorbent wick 200 will be described below with reference to Examples 1 to 3.

[0069] 25, in Example 1, (S1) a mold was first manufactured: a striped structure 201a was formed in a base 202 by photolithography, and the cross section of the striped structure 201a could be rectangular, trapezoidal, semicircular, or similar shapes. (S2) A metal layer was deposited: the substrate was subjected to necessary surface pretreatment, and then a metal layer 199 was deposited on the substrate. The base 202 and striped structure 201a were then removed, finally obtaining an independent liquid-absorbent wick 200. (S3) Capillary holes 250 were processed: the capillary holes 250 were processed in the liquid-absorbent wick 200. The formation of the porous liquid-absorbent wick 200 and the capillary holes 250 can be completed by methods such as laser processing, chemical etching, etching (e.g., ICP, RIE, DRIE), electrochemical processing, or mechanical processing. The shape of the capillary holes 250 may be circular, elliptical, arc-shaped, triangular, rectangular, trapezoidal, star-shaped, strip-shaped, etc., or a combination thereof.

[0070] Referring to Fig. 26, in Example 2, a striped structure 201a was formed on a base 202 by printing to obtain a substrate. The cross section of the striped structure 201a may be semicircular, major arc-shaped, minor arc-shaped, etc. Then, a metal layer 199 was deposited on the substrate, and the base 202 and striped structure 201a were removed to finally obtain a liquid-absorbent wick 200. Finally, capillary through-holes 250 were processed in the liquid-absorbent wick 200 by a laser method to finally obtain a porous liquid-absorbent wick 200.

[0071] 27, in Example 3, silk threads 201a were laid on a base 202 to obtain a mold substrate. Then, a metal layer 199 was deposited on the substrate, and the base 202 and striped structure 201a were removed to obtain a liquid-absorbent wick 200. Finally, capillary holes 250 were formed in the liquid-absorbent wick 200 using a laser method, finally obtaining a porous liquid-absorbent wick 200. The material of the silk threads was the same as that of the striped structure 201a described above.

[0072] The absorbent wick 200 manufactured using the above method is more effective when transporting working fluid because it has a greater capillary pressure and a smaller flow resistance. To verify the advanced features of this absorbent wick 200, a comparison test was conducted with a conventional copper silk mesh material. Both were 75 mm long. The copper silk mesh material was 300 mesh, with the copper silk threads having a diameter of 30 microns and a total thickness of 60 microns. The absorbent wick 200 manufactured using this manufacturing method had a total thickness of 51 microns, of which the thickness of the first bypass groove was 36 microns. The absorbent wick 200 had capillary holes 250 at both the evaporation end and condensation end. The width of each capillary hole 250 was 100 microns, and the aspect ratio was 1:10 (i.e., the effective capillary radius of the capillary holes 250 at both ends of the first bypass groove was the same). The length of the through-hole area, both at the condensation end and evaporation end, was 25 mm. The absorbent wick 200 and copper silk mesh material were sintered to a copper plate (corresponding to the cover plate) using the same heat treatment process to obtain a sintered structure (the sintered structure of the absorbent wick 200 and cover plate is shown in Figure 15). The absorbent wick 200 and copper plate formed a first capillary 210 and a second bypass groove 220, and capillary through-holes 250 were machined at both ends of the first capillary 210 using laser processing. After washing, drying, and reduction, the two sintered structures were immersed in deionized water at one end, and the water rising process in the material was photographed using a camera. The water level at each time point was then measured using image analysis.

[0073] Figure 28 shows the theoretical water-up time curve for the absorbent wick 200, the water-up time curve for copper silk mesh material, and the actual water-up process for four absorbent wicks 200 manufactured using the manufacturing method of this example. The four absorbent wicks 200 manufactured using the manufacturing method of this example have very similar sintered structure water-up curves, indicating the consistency of the material manufacturing process. Furthermore, the water-up speed and height are both far superior to those of the sintered copper silk mesh material. At the beginning of the water-up process, the water-up speed for the absorbent wick 200 is three to four times that of the copper silk mesh, and the final water-up height is nearly twice that of the copper silk mesh material. Therefore, the absorbent wick 200 has a better capillary flow effect on the working fluid.

[0074] In this specification, specific examples are used to explain the principles and embodiments of the present invention, and the description of the above examples is only used to help understand the method and core idea of ​​the present invention, and at the same time, for those skilled in the art, there are changes in the form for implementing the invention and the scope of application according to the idea of ​​the present invention. Therefore, the contents of this specification should not be understood as limitations on the present invention. [Explanation of symbols]

[0075] 100-Vapor Chamber 101-1st cover plate 102-Second cover plate 103-Steam Chamber 104-Support member 199-Deposited metal layer 200-Liquid absorption core 201-Photosensitive film 201a-Stripe mold structure 202-Base 210-1st capillary 220-2nd detour groove 230-Connection Channel 250-capillary through hole 300-hydraulic fluid 310-Second gas-liquid interface 320-First gas-liquid interface 400-Heat source area 410-Insulation Area 420-Exothermic Zone

Claims

1. an absorbent wick used to attach a cover plate to a shell, the absorbent wick having a first bypass groove, the first bypass groove used to form a first capillary with the cover plate; The liquid-absorbent wick is characterized in that the first capillary is used to connect the heat source area and the heat dissipation area, thereby allowing working fluid condensed in the heat dissipation area to return to the heat source area through the first capillary under the action of capillary pressure.

2. The absorbent wick of claim 1, characterized in that the shell has a vapor chamber located on one side of the absorbent wick away from the cover plate, and the absorbent wick has capillary holes formed therein, which are used to connect the first bypass groove and the vapor chamber, thereby allowing the working liquid and its vapor to flow between the first bypass groove and the vapor chamber.

3. 3. The liquid-absorbent wick according to claim 2, further comprising a second bypass groove located on one side of the liquid-absorbent wick closer to the steam chamber, the second bypass groove being used to connect the heat source area with the heat dissipation area, so that working fluid condensed in the heat dissipation area can flow back to the heat source area through the second bypass groove under the action of capillary pressure.

4. The absorbent wick of claim 3, characterized in that a first end of the first capillary is used to be positioned in the heat source area, and a second end of the first capillary is used to be positioned in the heat dissipation area, and the effective capillary radius of the capillary hole positioned at the first end of the first capillary is smaller than the effective capillary radius of the capillary hole positioned at the second end of the first capillary, thereby increasing the capillary pressure that causes the working fluid to return to the heat source area.

5. The absorbent wick of claim 1, characterized in that the absorbent wick also has a connecting channel and includes a plurality of the first capillaries, and two adjacent first capillaries are connected through the connecting channel, thereby allowing the working liquid and vapor of the working liquid to flow between different first capillaries.

6. 6. The absorbent wick according to claim 5, wherein the connecting channel includes a connecting groove, which is used to form a second capillary together with the cover plate.

7. A vapor chamber comprising the absorbent wick of claim 1, 5 or 6, and also comprising the shell, wherein the shell has the cover plate, one side of the cover plate is used for contacting a heat source, and the other side of the cover plate forms the first capillary together with the first bypass groove.

8. The vapor chamber of claim 7, wherein the shell has a vapor chamber located on one side of the absorbent wick away from the cover plate, and the absorbent wick has a capillary hole formed therein, the capillary hole being used to connect the first bypass groove with the vapor chamber, thereby allowing the working liquid and its vapor to flow between the first bypass groove and the vapor chamber.

9. A method for manufacturing a liquid absorbent wick used to manufacture the liquid absorbent wick according to claim 1, comprising the steps of: Step S1: A substrate is obtained by arranging a stripe structure on a surface of a base, and the surface of the substrate on which the stripe structure is formed is a deposition surface; Step S2: depositing a metal layer on the deposition surface of the substrate, the metal layer covering at least a portion of the deposition surface, the material of the metal layer being different from both the material of the stripe structure and the material of the base; and step S3 of removing the base and the striped structure, and forming the first detour groove after removing the striped structure.

10. The method for manufacturing a liquid absorbent wick according to claim 9, further comprising the step S4 of forming capillary holes in the first bypass groove.

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