Novel capillary structure and its processing method, and vapor chamber

Abstract

The application discloses a novel capillary structure and a processing method thereof, a vapor chamber, and the processing method of the novel capillary structure. The processing method comprises the following steps: providing a foil with a certain thickness, wherein the foil has a first surface and a second surface opposite to each other in the thickness direction; forming a plurality of through holes spaced apart from each other on the foil by penetrating the first surface and the second surface of the foil in the thickness direction by using a laser beam; and making each through hole located at the edge of the second surface of the foil to correspondingly form an annular protrusion around the edge, so as to obtain the novel capillary structure; and each annular protrusion corresponds to each through hole. The climbing speed of the novel capillary structure is faster than that of a traditional woven wire mesh, which indicates that the capillary force of the novel capillary structure is greater, and the capillary effect is better. When the novel capillary structure is applied to the vapor chamber, the vapor chamber can be thinned, and the heat conduction and heat dissipation effect of the vapor chamber can be obviously improved.

Description

Technical Field

[0001] This invention relates to the field of heat dissipation technology, and in particular to a novel capillary structure and its processing method, as well as a heat spreader using the novel capillary structure. Background Technology

[0002] With the development of electronic and electrical technology and the increasing demands of users, electronic products used in daily life, scientific research, and education are becoming increasingly functional and powerful, leading to more severe heat generation issues. Vapor chambers (VCs) are currently an ideal solution for addressing the heat dissipation problems of various electronic products.

[0003] With the increasing demand for portability in electronic products, higher requirements have been placed on the lightweight and thinness of vapor chambers. Capillary structure is a key component of vapor chambers, which uses capillary action to achieve liquid reflux, thereby completing heat transfer and dissipation.

[0004] In existing technologies, the capillary structure inside a heat spreader typically employs woven wire mesh; see attached diagram. Figure 6 As shown, since woven wire mesh is formed by interlacing warp and weft threads, its thickness is limited by the wire diameter and cannot be made thinner. Because thinner wires are more prone to breakage, this makes processing difficult and results in low yield. To ensure the yield of woven wire mesh, the current thickness is typically 0.06mm, with the thinnest being only 0.045mm. This not only results in very high costs but also significantly limits the production and application of thinner and lighter heat spreaders. Therefore, this application provides a novel capillary structure that, compared to traditional woven wire mesh, allows for further thinner and lighter applications of heat spreaders while also improving their heat conduction and dissipation performance.

[0005] This application addresses at least one of the aforementioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to provide a novel capillary structure and its processing method, as well as a heat spreader. The processing method is simple and fast, with low manufacturing cost. Furthermore, the heat spreader using this novel capillary structure not only has good heat conduction and heat dissipation effects, but also features lightweight, thinness, and good structural strength.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A first aspect of the present invention provides a novel method for processing capillary structures, comprising:

[0009] A foil of a certain thickness is provided, the foil having a first side and a second side opposite to each other along the thickness direction;

[0010] Along the thickness direction, a laser beam is used to sequentially penetrate the first and second surfaces of the foil to form multiple spaced through holes on the foil; and each through hole is located at the edge of the second surface of the foil, correspondingly forming an annular protrusion around the edge, thus obtaining a novel capillary structure;

[0011] Each of the annular protrusions corresponds one-to-one with each of the through holes.

[0012] In some possible implementations of the first aspect, the arrangement of the multiple through holes is a rectangular array, a ring array, or an unequal-spacing array.

[0013] In some possible embodiments of the first aspect, the thickness of the foil is 0.005 to 0.015 mm; and / or

[0014] The thickness of the novel capillary structure is 0.02–0.05 mm.

[0015] In some possible embodiments of the first aspect, the diameter of the through hole is 0.02 to 0.15 mm; and / or

[0016] The distance between the centers of two adjacent through holes is 0.04 to 0.3 mm.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. The number, size, shape, and arrangement of the through holes in the novel capillary structure can be designed and adjusted independently.

[0019] 2. The thickness of the new capillary structure is 0.02-0.05mm, enabling the application of ultra-thin heat spreaders.

[0020] 3. Using laser beam processing, the porous forming of novel capillary structures can be achieved in just nanoseconds. The process is simple and highly efficient. Laser processing can achieve a minimum hole diameter of 0.02mm and a minimum distance between the centers of two adjacent holes of 0.04mm, which is unattainable by traditional stamping processes.

[0021] 4. Compared with traditional woven wire mesh, the new capillary structure has a faster climbing speed and greater capillary force in the water absorption test. Its capillary effect on water is better, and its application in the heat exchanger will improve the heat conduction and heat dissipation effect of the heat exchanger.

[0022] A second aspect of the present invention provides a novel capillary structure comprising:

[0023] A foil has a first side and a second side opposite each other along the thickness direction; the foil has a plurality of through holes penetrating the foil along the thickness direction;

[0024] Each through-hole is located at the edge of the second side of the foil, corresponding to an annular protrusion formed around the edge.

[0025] Each of the annular protrusions corresponds one-to-one with each of the through holes.

[0026] In some possible embodiments of the second aspect, the foil is further provided with at least one guide groove extending through the foil along the thickness direction.

[0027] In some possible embodiments of the second aspect, the first side of the foil includes a first region and a second region;

[0028] The density of through holes in the first region is greater than the density of through holes in the second region; and / or

[0029] The diameter of the through hole in the first region is smaller than the diameter of the through hole in the second region.

[0030] A third aspect of the present invention provides a heat spreader having a hot end in contact with a heat source and a cold end away from the heat source, and a first direction pointing from the hot end to the cold end and a second direction perpendicular to the first direction, wherein a novel capillary structure or the novel capillary structure described above is obtained by applying the above processing method, the heat spreader comprising:

[0031] A first cover plate has a first surface and a first back surface disposed opposite to each other along the thickness direction. The first cover plate is provided with a first groove, which is formed by a portion of the first surface recessing into the interior of the first cover plate.

[0032] The second cover plate has a second surface and a second back surface that are disposed opposite to each other along the thickness direction. The second cover plate is provided with multiple rows of support protrusions that are spaced apart along the second direction. A second groove is formed between two adjacent rows of support protrusions. The support protrusions are formed by a portion of the second surface recessed into the interior of the second cover plate.

[0033] A novel capillary structure is fitted into the first groove of the first cover plate, wherein the annular protrusion is located on the bottom wall of the first groove, and a water return passage is formed between two adjacent annular protrusions and the bottom wall of the first groove.

[0034] The first surface of the first cover plate and the second back surface of the second cover plate are covered together, and the first cover plate and the second cover plate are fixedly connected to form a closed inner cavity between the first cover plate and the second cover plate. The closed inner cavity is used to accommodate the novel capillary structure and the cooling medium of the heat exchange plate.

[0035] The support protrusion abuts against the novel capillary structure, wherein the support protrusion abuts against the first surface of the foil.

[0036] The beneficial effects of the present invention are at least as follows: the present application improves the heat conduction and heat dissipation effect and structural strength of the heat exchange plate, and achieves the thinning of the heat exchange plate while having both good thermal conductivity and structural stability.

[0037] First, by utilizing the capillary action of the novel capillary structure, the cooling medium inside the heat exchanger can be rapidly returned to the heat source after evaporation due to heating, thereby improving the heat conduction efficiency and maintaining a continuous heat conduction cycle, further improving the heat conduction and heat dissipation effect of the heat exchanger.

[0038] Second, by having the support protrusion abut against the novel capillary structure, the support protrusion can effectively fix the novel capillary structure, ensuring that the novel capillary structure can be tightly fixed between the first cover plate and the second cover plate, thereby improving the stability of the novel capillary structure inside the heat exchange plate.

[0039] Third, the first and second grooves create sufficiently large steam channels, allowing for more complete steam diffusion and ensuring efficient heat transfer within the vapor chamber. This results in a more even distribution of heat across the entire vapor chamber, enhancing its thermal conductivity and heat dissipation. This avoids situations where small steam channels prevent efficient and even heat distribution across the vapor chamber, thus affecting evaporation efficiency.

[0040] Fourth, compared with traditional woven wire mesh, the new capillary structure has greater capillary force, better water absorption, and more obvious capillary effect, thus improving the heat conduction and heat dissipation effect of the heat spreader.

[0041] In some possible implementations of the third aspect, when the first cover plate and the second cover plate are made of stainless steel or titanium, the novel capillary structure is made of stainless steel; or

[0042] When the first cover plate and the second cover plate are made of copper, copper-aluminum composite, or copper-steel composite material, the novel capillary structure is made of copper; or

[0043] When the first cover plate and the second cover plate are made of titanium, the novel capillary structure is also made of titanium.

[0044] In some possible embodiments of the third aspect, the first cover plate includes a first copper cover plate and a first aluminum cover plate stacked together; the second cover plate includes a second aluminum cover plate and a second copper cover plate stacked together.

[0045] The first aluminum cover plate has a first aluminum surface and a first aluminum back surface disposed opposite to each other along the thickness direction, and the first copper cover plate has a first copper surface and a first copper back surface disposed opposite to each other along the thickness direction. The first aluminum surface and the first copper back surface are attached together, and a portion of the first copper surface is recessed into the first cover plate to form the first groove.

[0046] The second aluminum cover plate has a second aluminum surface and a second aluminum back surface arranged opposite to each other along the thickness direction. The second copper cover plate has a second copper surface and a second copper back surface arranged opposite to each other along the thickness direction. The second aluminum back surface and the second copper surface are attached to each other. A portion of the second aluminum surface is recessed into the second cover plate to form multiple rows of support protrusions. The second groove is formed between two adjacent rows of support protrusions.

[0047] In some possible implementations of the third aspect, the support protrusion does not contact the inner wall of the first groove.

[0048] In some possible implementations of the third aspect, the depth of the second groove is less than the depth of the first groove.

[0049] In some possible implementations of the third aspect, the thickness of the novel capillary structure is less than the depth of the second groove.

[0050] In some possible embodiments of the third aspect, the thickness of the first copper cover plate is 0.005 to 0.1 mm, the thickness of the first aluminum cover plate is 0.01 to 0.1 mm, the thickness of the second copper cover plate is 0.005 to 0.1 mm, and the thickness of the second aluminum cover plate is 0.01 to 0.1 mm. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the molding structure of the novel capillary structure according to an embodiment of the present invention;

[0052] Figure 2 This is a schematic diagram of the guide groove in the novel capillary structure according to an embodiment of the present invention;

[0053] Figure 3 This is a schematic diagram showing the distribution of the first region and the second region on the first side of the foil in an embodiment of the present invention;

[0054] Figure 4 This is a schematic diagram of the distribution structure of the guide groove and the first and second regions in the novel capillary structure in an embodiment of the present invention;

[0055] Figure 5 This is a schematic diagram of the structure of the heat exchange plate according to an embodiment of the present invention;

[0056] Figure 6 This is a schematic diagram of the structure of a traditional woven wire mesh.

[0057] In the figure, 1 is the first cover plate; 2 is the second cover plate; 3 is the novel capillary structure; 13 is the first groove; 21 is the second aluminum cover plate; 22 is the second copper cover plate; 23 is the support protrusion; 24 is the second groove; 31 is the foil; 32 is the through hole; 33 is the annular protrusion; and 34 is the guide groove. Detailed Implementation

[0058] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided to make the invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore repeated descriptions of them will be omitted.

[0059] In a first aspect of this embodiment, a novel method for processing capillary structures is provided, comprising steps S1-S3.

[0060] Step S1: Provide a foil 31 of a certain thickness, the foil 31 having a first side and a second side opposite to each other along the thickness direction.

[0061] The foil 31 is made of stainless steel, titanium, or copper, and its thickness T1 is 0.005–0.015 mm, for example, 0.005 mm, 0.006 mm, 0.007 mm, 0.008 mm, 0.009 mm, 0.01 mm, 0.011 mm, 0.012 mm, 0.013 mm, 0.014 mm, or 0.015 mm. In this embodiment, the foil 31 is made of stainless steel, its thickness T1 is 0.01 mm, its length is 150 mm, and its width is 50 mm.

[0062] Step S2: Along the thickness direction of the foil 31, a laser beam is used to sequentially penetrate the first and second surfaces of the foil 31 to form multiple spaced through holes 32 on the foil 31, and each through hole 32 is located at the edge of the second surface of the foil 31, correspondingly forming annular protrusions 33 around the edge, thus obtaining a novel capillary structure 3.

[0063] See appendix Figure 1 As shown, under the high-temperature heating effect of the laser beam, a local area on the surface of the foil 31 will melt and form a through hole 32. The metal material corresponding to the through hole 32 will expand outward on the second side of the foil 31, thereby forming an annular protrusion 33 (metal burr) around the edge of the through hole 32.

[0064] It should be noted that each annular protrusion 33 corresponds one-to-one with each through hole 32.

[0065] In some specific embodiments, the shape of the through hole 32 can be one or more of polygons, circles, ellipses or teardrop shapes. It should be noted that the above shapes are not a limitation on the shape of the through hole 32 in this application. The shape of the through hole 32 can be regular or irregular. Multiple through holes can have the same or different shapes. In this embodiment, the through hole 32 can be circular.

[0066] In some specific embodiments of the first aspect, the plurality of through holes 32 are arranged in a rectangular array, a ring array, or an unequal-spacing array. In this embodiment, the plurality of through holes 32 can be arranged in a rectangular array.

[0067] In some specific embodiments of the first aspect, the diameter D of the through hole 32 is 0.02 to 0.15 mm. The diameters of the multiple through holes 32 can be equal or unequal, for example, 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.011 mm, 0.012 mm, 0.013 mm, 0.014 mm, and 0.015 mm. In this embodiment, the diameter D of the through hole can be 0.06 mm.

[0068] Furthermore, the distance H between the centers of two adjacent through holes 32 is 0.04–0.3 mm; preferably, H = 2D. In this embodiment, the distance H between the centers of two adjacent through holes 32 is 0.12 mm.

[0069] In some specific embodiments of the first aspect, the thickness T of the novel capillary structure is 0.02 to 0.05 mm, and the thickness T2 of the annular protrusion 33 is understood to be T = T1 + T2. In this embodiment, the thickness T of the novel capillary structure can be 0.035 mm, and the thickness T2 of the annular protrusion 33 is 0.025 mm.

[0070] The number, size, shape, and arrangement of the through holes in the novel capillary structure 3 in this application can be designed and adjusted independently. The thickness of the novel capillary structure 3 is 0.02–0.05 mm, enabling the application of ultra-thin heat spreaders.

[0071] This application utilizes a low-power MOPA laser beam for processing, achieving the integrated molding of multiple through holes 32 and annular protrusions 33 in the novel capillary structure 3 in just nanoseconds. The process is simple and highly efficient. Laser processing allows for a minimum aperture D of 0.02 mm and a minimum center-to-center distance H of 0.04 mm between adjacent through holes 32, which is unattainable with traditional stamping processes (stamping is limited by mold processing; current research indicates a minimum aperture of 0.1 mm and a minimum distance H of 0.15 mm for through holes). Compared to traditional woven mesh, the novel capillary structure 3 exhibits faster climbing speed and greater capillary force in water absorption tests, demonstrating better capillary action on water. Its application in heat spreaders improves the heat conduction and dissipation performance of the heat spreader.

[0072] A second aspect of this embodiment also provides a novel capillary structure, obtained by the above-described processing method, combined with the attached... Figure 1 As shown, the novel capillary structure 3 includes a foil 31.

[0073] The foil 31 has a first surface and a second surface that are opposite each other along the thickness direction; the foil 31 is provided with a plurality of through holes 32 that penetrate the foil along the thickness direction.

[0074] Each through-hole 32 is located at the edge of the second side of the foil 31, and a corresponding annular protrusion 33 is formed around the edge.

[0075] Each annular protrusion 33 corresponds one-to-one with each through hole 32.

[0076] Combined with appendix Figure 2-5 As shown, in some specific embodiments of the second aspect, at least one guide groove 34 is also provided on the foil 31, extending through the foil 31 in the thickness direction.

[0077] In some specific embodiments of the second aspect, the first side of the foil 31 includes a first region and a second region.

[0078] The density of through holes 32 in the first region is greater than that in the second region. The diameter of the through holes 32 in the first region is smaller than that in the second region.

[0079] Combined with appendix Figure 5 As shown, a third aspect of this embodiment provides a method for processing a heat spreader, utilizing the novel capillary structure 3 described above. The heat spreader has a hot end in contact with a heat source and a cold end away from the heat source. The direction from the hot end to the cold end is a first direction, and the direction perpendicular to the first direction is a second direction. The heat spreader processing method includes the following steps S10-S12.

[0080] Step S10: Provide a first cover plate 1 and a second cover plate 2. The first cover plate 1 is provided with a first groove 13, and the second cover plate 2 is provided with multiple rows of support protrusions 23 spaced apart along a second direction. A second groove 24 is formed between two adjacent rows of support protrusions 23.

[0081] The cross-sectional shape of the first groove 13 and the second groove 24 can be rectangular, isosceles trapezoid, etc., and in this embodiment, it is preferably an isosceles trapezoid. The first groove 13 and the second groove 24 form a sufficiently large steam channel, allowing the steam to diffuse more fully, ensuring efficient heat transfer within the heat spreader, and making the heat more evenly distributed across the entire heat spreader, thereby enhancing the heat conduction and heat dissipation effect of the heat spreader.

[0082] When the first cover plate 1 and the second cover plate 2 are made of stainless steel or titanium, the novel capillary structure 3 is made of stainless steel. When the first cover plate 1 and the second cover plate 2 are made of copper, copper-aluminum composite, or copper-steel composite, the novel capillary structure 3 is made of copper; when the first cover plate 1 and the second cover plate 2 are made of titanium, the novel capillary structure 3 is made of titanium.

[0083] In one embodiment of this invention, when both the first cover plate 1 and the second cover plate 2 are made of stainless steel, the novel capillary structure 3 is also made of stainless steel. In this embodiment, the thickness of the first cover plate 1 is preferably 0.05 mm; the thickness of the second cover plate 2 is preferably 0.05 mm.

[0084] In another embodiment of this invention, the first cover plate 1 and the second cover plate 2 can be made of copper-aluminum composite material, and the novel capillary structure 3 is made of copper.

[0085] The first cover plate 1 and the second cover plate 2, made of composite materials, are now described in detail. The first cover plate 1 includes a first copper cover plate and a first aluminum cover plate stacked together. The first aluminum cover plate has a first aluminum surface and a first aluminum back surface that are arranged opposite each other along the thickness direction. The first copper cover plate has a first copper surface and a first copper back surface that are arranged opposite each other along the thickness direction. The first aluminum surface and the first copper back surface are bonded together, and a portion of the first copper surface is recessed into the first cover plate 1 to form a first groove 13. Preferably, the first cover plate 1 is symmetrical with respect to the center line of the first groove 13.

[0086] The second cover plate 2 includes a second aluminum cover plate and a second copper cover plate stacked together. The second aluminum cover plate has a second aluminum surface and a second aluminum back surface that are arranged opposite to each other along the thickness direction. The second copper cover plate has a second copper surface and a second copper back surface that are arranged opposite to each other along the thickness direction. The second aluminum back surface and the second copper surface are attached together. Part of the second aluminum surface is recessed into the interior of the first cover plate 2 to form multiple rows of support protrusions 23. A second groove 24 is formed between two adjacent rows of support protrusions 23.

[0087] When the first cover plate 1 is close to the heat source, the material of the first cover plate 1 includes copper, which has both excellent thermal conductivity and ductility, and aluminum, which has both excellent thermal conductivity, lightweight, ductility and corrosion resistance, so that the heat source can be conducted to the entire heat exchange plate through the first cover plate 1.

[0088] The second cover plate 2 is far away from the heat source. The material of the second cover plate 2 also includes copper, which has excellent thermal conductivity and ductility, and aluminum, which has excellent thermal conductivity, lightweight, ductility and corrosion resistance. The second cover plate 2 fully dissipates the heat conducted from the heat source to the heat distribution plate.

[0089] It should be further noted that the thickness of the first copper cover plate is 0.005–0.1 mm, the thickness of the first aluminum cover plate is 0.01–0.1 mm, the thickness of the second copper cover plate is 0.005–0.1 mm, and the thickness of the second aluminum cover plate is 0.01–0.1 mm. Using these thickness specifications can improve the heat conduction and dissipation effect of the heat spreader while achieving ultra-thinness. In this embodiment, the thickness of the first copper cover plate is preferably 0.01 mm, the thickness of the first aluminum cover plate is preferably 0.04 mm, the thickness of the second copper cover plate is preferably 0.01 mm, and the thickness of the second aluminum cover plate is preferably 0.04 mm.

[0090] In some embodiments, when there is an even number of support protrusions 23, the second cover plate 2 is symmetrical with respect to the center line of the middle second groove 24 among all the second grooves 24; when there is an odd number of support protrusions 23, the second cover plate 2 is symmetrical with respect to the center line of the middle support protrusion 23 among all the support protrusions 23.

[0091] In some embodiments, steps S100-S300 are included before the first cover plate 1 and the second cover plate 2 are provided.

[0092] Step S100: Provide a first substrate and a second substrate. The first substrate includes a first copper substrate and a first aluminum substrate stacked sequentially, and the second substrate includes a second aluminum substrate and a second copper substrate stacked sequentially.

[0093] Step S200: The first substrate is stamped to form a first groove 13 on the first substrate, and the first cover plate 1 is formed after the first substrate is stamped.

[0094] The first copper substrate and the first aluminum substrate are rolled into a first substrate, and then the first substrate is stamped to form a first groove 13, thereby obtaining a first cover plate 1 with the first groove 13.

[0095] Step S300: The second substrate is stamped to form a protrusion 23 on the second substrate. The second substrate is stamped to form a second cover plate 2.

[0096] The second copper substrate and the second aluminum substrate are rolled into a second substrate, and then the second substrate is stamped to form multiple rows of support protrusions 23 spaced apart along the second direction. A second groove 24 is formed between two adjacent rows of support protrusions 23, thereby obtaining a second cover plate 2 provided with support protrusions 23 and second grooves 24.

[0097] When the copper and aluminum cover plates in the first cover plate 1 and the second cover plate 2 come into contact with impurities such as air, moisture, and carbon dioxide, they form an electrolyte, causing aluminum to become the negative electrode and copper to become the positive electrode, resulting in electrochemical corrosion. The corrosion products (such as Al(OH)3 and AlO(OH)) produced by electrochemical corrosion affect the thermal conductivity of the copper-aluminum composite plate surface. Corrosion increases the contact resistance between copper and aluminum, affecting heat transfer, reducing the thermal conductivity of the heat spreader, and long-term corrosion may damage the structure of the first cover plate 1 and the second cover plate 2, affecting the overall structural strength of the heat spreader.

[0098] Therefore, in some preferred embodiments, the copper and aluminum plates in the first cover plate 1 and the second cover plate 2 are fused together by cold rolling or explosive rolling to form a brazing-free structure, which effectively prevents the negative impact of electrochemical corrosion on the heat conduction and heat dissipation effect and structural strength of the heat spreader.

[0099] Step S11: Provide a novel capillary structure 3 and attach the novel capillary structure 3 to the first groove 13 of the first cover plate 1.

[0100] Furthermore, the annular protrusions 33 of the novel capillary structure 3 are attached and fixed to the bottom wall of the first groove 13, and a water return passage is formed between two adjacent annular protrusions 33 and the bottom wall of the first groove 13.

[0101] Furthermore, the annular protrusion 33 of the novel capillary structure 3 can be attached and fixed to the bottom wall of the first groove 13 of the first cover plate 1 by diffusion welding; or the novel capillary structure 3 can be fixed to the bottom wall of the first groove 13 of the first cover plate 1 by resistance welding or laser welding.

[0102] To ensure a good bond strength between the novel capillary structure 3 and the first cover plate 1, in this embodiment, a portion of the annular protrusion 33 is first fixed in the first groove 13 of the first cover plate 1 for positioning by resistance welding or laser welding. Then, the novel capillary structure 3 is tightly bonded to the bottom wall of the first groove 13 of the first cover plate 1 by diffusion welding. The diffusion welding process conditions include: the welding gas is a nitrogen-hydrogen mixture (nitrogen content 5-10%), the gas flow rate is 100-200 L / min, the welding temperature is 250-500℃, and the welding pressure is 10000-20000 PSL.

[0103] The capillary action of the annular protrusion 33 in the novel capillary structure 3 allows the cooling medium in the heat spreader to rapidly flow back to the heat source after evaporation due to heating. This reduces the resistance during the cooling medium's return flow, thereby reducing the overall thermal resistance of the heat spreader and improving heat conduction and dissipation efficiency, thus maintaining a continuous heat conduction cycle. On the other hand, the annular protrusion 33 adheres to the bottom wall of the first groove 13 without extending to its sidewall. This increases the contact area between the groove wall and the cooling medium, meaning the contact between the cooling medium and the inner wall of the first cover plate 1 is more complete. This increases the path and efficiency of heat transfer, allowing heat to be more evenly distributed across the entire heat spreader. More heat can be directly transferred from the first cover plate 1 to the cooling medium, reducing heat transfer resistance and thus improving heat conduction and dissipation efficiency.

[0104] It should be further noted that the thickness of the novel capillary structure 3 is less than the depth (D1) of the first groove 13. The thickness of the novel capillary structure 3 + the depth (D2) of the second groove 24 = the depth of the first groove 13. In a preferred embodiment, the depth of the second groove 24 is greater than the thickness of the novel capillary structure 3. The thickness of the novel capillary structure 3 is 0.035 mm, the depth of the first groove 13 is 0.15 mm, and the depth of the second groove 24 is 0.115 mm. This specification of heat spreader has good thermal conductivity and heat dissipation effect.

[0105] Since the depth of the second groove 24 is greater than the thickness of the novel capillary structure 3, the contact area between the groove wall of the second groove 24 and the cooling medium in the heat spreader plate is increased. This means that the contact between the cooling medium and the inner wall of the second cover plate 2 is more sufficient, which can increase the path and efficiency of heat transfer, make the heat more evenly distributed on the entire heat spreader plate, and allow more heat to be directly transferred from the second cover plate 2 to the cooling medium, reducing the resistance to heat transfer and thus further improving the heat conduction and heat dissipation efficiency.

[0106] Furthermore, the inner wall of the first groove 13 does not contact the supporting protrusion 23. This is to prevent interference between the supporting protrusion 23 and the inner wall of the first groove 13 when the first cover plate 1 and the second cover plate 2 are covered, which would prevent the new capillary structure 3 from fully contacting the supporting protrusion 23, affecting the reliability of the heat spreader, and thus negatively impacting the heat conduction and heat dissipation effect and service life of the heat spreader.

[0107] Furthermore, the depth of the first groove 13 is greater than the depth of the second groove 24, and the depth of the first groove 13 is 0.15mm, while the depth of the second groove 24 is 0.115mm. This is to ensure that the thickness of the heat spreader plate is made ultra-thin, and to ensure that the first groove 13 can accommodate the new capillary structure 3 so that the new capillary structure 3 can abut against the support protrusion 23.

[0108] Step S12: Cover the first cover plate 1 and the second cover plate 2 together so that the support protrusion 23 abuts against the novel capillary structure 3, and fix the first cover plate 1 and the second cover plate 2 to form a closed inner cavity between the first cover plate 1 and the second cover plate 2. The closed inner cavity is used to accommodate the novel capillary structure 3 and the cooling working fluid of the heat exchange plate.

[0109] The support protrusion 23 abuts against the novel capillary structure 3, which enables the support protrusion 23 to play a good role in fixing the novel capillary structure 3, ensuring that the novel capillary structure 3 can be tightly fixed between the first cover plate 1 and the second cover plate 2, thereby improving the stability of the novel capillary structure 3 inside the heat exchange plate.

[0110] The stable new capillary structure 3 ensures smooth circulation of the cooling medium (usually water or other coolant) within the vapor chamber during evaporation and condensation. When one end of the vapor chamber is heated, the medium evaporates into vapor, which diffuses within the chamber, carrying heat. Subsequently, the vapor condenses into liquid at the cooler end, releasing heat. In this process, the stability of the new capillary structure 3 ensures the smooth flow of the medium from one area to another, achieving efficient heat transfer. Secondly, the stability of the new capillary structure 3 also enhances the overall structural strength of the vapor chamber. During operation, the vapor chamber may be subjected to various external pressures and impacts, and the stable new capillary structure 3 effectively resists these forces, maintaining the integrity of the vapor chamber. This not only extends the service life of the vapor chamber but also ensures its stability and reliability in various application scenarios. Finally, the stability of the novel capillary structure 3 also helps to improve the heat transfer efficiency of the vapor chamber. When heat is transferred through the vapor chamber, the novel capillary structure 3 can quickly transfer heat from the heat source to the entire vapor chamber, achieving a uniform distribution of heat. This uniform heat distribution effect is crucial for improving the heat dissipation performance of electronic devices, as it can effectively reduce the risk of local overheating, thereby protecting electronic components from damage.

[0111] It should be noted that the cooling medium is a liquid phase change material, such as liquid water, ethanol, and acetone. Through the transformation of the cooling medium from liquid to gas and back to liquid, heat is rapidly dissipated, thus maximizing the heat conduction and dissipation effect of the heat spreader. To ensure that the transformation process of the cooling medium from liquid to gas and back to liquid is not affected by impurities, the sealed inner cavity is generally in a vacuum state, thereby improving the heat conduction and dissipation effect of the heat spreader. In this embodiment, the cooling medium is water.

[0112] In a specific embodiment of the third aspect, the step of the first cover plate 1 and the second cover plate 2 covering each other includes steps S120a-S122a.

[0113] Step S120a: Cover the side of the second cover plate 2 where the support protrusion 23 is formed with the side of the first cover plate 1 where the first groove 13 is formed, so that the support protrusion 23 abuts against the novel capillary structure 3.

[0114] Step S121a: The first part of the side of the first cover plate 1 from which the first groove 13 is formed, excluding the first groove 13, corresponds to the second part of the side of the second cover plate 2 from which the support protrusion 23 is formed, excluding the support protrusion 23.

[0115] Step S122a: Seal the first part and the second part along the preset molecular diffusion region by diffusion welding.

[0116] In this embodiment, a low-temperature diffusion furnace is used, and the process conditions for diffusion welding include: the welding gas is a nitrogen-hydrogen mixture (nitrogen content 5-10%), the gas flow rate is 100-200 L / min, the welding temperature is 250-500℃, and the welding pressure is 10000-20000 PSL.

[0117] Because aluminum has a low melting point, the first cover plate 1 and the second cover plate 2 can be tightly bonded together through a low-temperature and low-pressure diffusion welding process. Since the gas used during welding is protected by a nitrogen-hydrogen mixture, there is no need for further reduction treatment, and the process can be directly carried out in the later stages.

[0118] In another embodiment, the difference from the previous embodiment is that the method of closing the first cover plate 1 and the second cover plate 2 is different. The method of closing the first cover plate 1 and the second cover plate 2 in this embodiment includes steps S120b-S122b.

[0119] The side of the second cover plate 2 that forms the support protrusion 23 is covered onto the side of the first cover plate 1 that forms the first groove 13, so that the support protrusion 23 abuts against the novel capillary structure 3.

[0120] The first portion of the side of the first cover plate 1 from which the first groove 13 is formed, excluding the first groove 13, corresponds to the second portion of the side of the second cover plate 2 from which the support protrusion 23 is formed, excluding the support protrusion 23.

[0121] The first and second parts are sealed together along a preset sealing line by laser welding. In this embodiment, a laser welding machine is used for laser welding.

[0122] Furthermore, after the first cover plate 1 and the second cover plate 2 are fitted together by laser welding, the fitted first cover plate 1 and the second cover plate 2 are subjected to low-temperature reduction treatment. The conditions for low-temperature reduction are: the reducing gas is a nitrogen-hydrogen mixture (nitrogen content 5-10%), the gas flow rate is 100-200 L / min, and the reduction temperature is 250-500℃.

[0123] Laser welding has a high sealing efficiency, generally taking only 1-5 seconds to complete. However, the lack of protective gas during laser welding causes the copper layer to oxidize. Therefore, a low-temperature reduction treatment is subsequently used to eliminate residual stress and deformation at the welded area, ensuring the mechanical properties of the heat spreader.

[0124] Combined with appendix Figure 5 As shown, the fourth aspect of this embodiment also provides a heat spreader plate, which is processed by the above method. The heat spreader plate has a hot end in contact with a heat source and a cold end away from the heat source, as well as a first direction from the hot end to the cold end and a second direction perpendicular to the first direction. The heat spreader plate includes a first cover plate 1, a second cover plate 2 and a novel capillary structure 3.

[0125] The first cover plate 1 has a first surface and a first back surface that are disposed opposite to each other along the thickness direction. The first cover plate 1 is provided with a first groove 13, which is formed by a portion of the first surface being recessed into the interior of the first cover plate 1.

[0126] The second cover plate 2 has a second surface and a second back surface that are arranged opposite to each other along the thickness direction. The second cover plate 2 is provided with multiple rows of support protrusions 23 that are spaced apart along the second direction. A second groove 24 is formed between two adjacent rows of support protrusions 23. The support protrusions 23 are formed by recessing part of the second surface into the second cover plate 2. The inner wall of the first groove 13 does not contact the support protrusions 23. The depth of the second groove 24 is less than the depth of the first groove 13. The first cover plate 1 is made of the same material as the first cover plate 2, which is stainless steel.

[0127] The novel capillary structure 3 is fitted into the first groove 13 of the first cover plate 1, and the thickness of the novel capillary structure 3 is less than the depth of the second groove 24. It should be noted that the annular protrusion 33 of the novel capillary structure 3 is located on the bottom wall of the first groove 13, and a water return passage is formed between two adjacent annular protrusions 33 and the bottom wall of the first groove 13.

[0128] The first surface of the first cover plate 1 and the second back surface of the second cover plate 2 are covered together, and the first cover plate 1 and the second cover plate 2 are fixedly connected so that a closed inner cavity is formed between the first cover plate 1 and the second cover plate 2. The closed inner cavity is used to accommodate the novel capillary structure 3 and the cooling medium of the heat exchange plate.

[0129] The support protrusion 23 abuts against the novel capillary structure 3. It should be noted that the support protrusion 33 abuts against the first surface of the foil 31 of the novel capillary structure 3.

[0130] It should be noted that, due to the angle between the annular protrusion 33 and the bottom wall of the first groove 13, capillary force is generated around the contact edge between the annular protrusion 33 and the bottom wall of the groove. Under the capillary action of the capillary force, it can absorb water more than other areas, thus forming a water storage area. When the heat source heats the cooling medium at the hot end, the cooling medium will vaporize to form water vapor, creating a pressure difference in the closed inner cavity. The water vapor diffuses through the through hole 32 under the action of the pressure difference to the cold end and condenses into water, and is fully collected in the water storage area. Since a water return passage is formed between the two adjacent annular protrusions 33 and the bottom wall of the first groove 13, under the pressure difference formed by the condensation of water vapor and the capillary action at the edge of the annular protrusion 33, the water in the water storage area will quickly flow back to the hot end through the water return passage, thereby accelerating the heat conduction cycle, enabling the heat source to conduct heat and dissipate heat more quickly, and improving the heat conduction and dissipation effect of the entire heat spreader.

[0131] Combined with appendix Figure 1-4 As shown, in some specific embodiments, the diameter D of the through hole 32 is 0.02 to 0.15 mm, and the distance H between the centers of two adjacent through holes 32 is 0.04 to 0.3 mm.

[0132] Larger apertures result in lower resistance to water vapor passing through the foil, leading to higher transmittance. However, larger apertures also increase the distance between the centers of adjacent through-holes, requiring greater capillary force to pull the cooling medium back from the cold end to the hot end. This increases the resistance to water recirculation between adjacent water storage areas along the cold-to-hot direction. Conversely, smaller apertures result in higher resistance to water vapor passing through the foil 31, lower transmittance, and smaller distance between the centers of adjacent through-holes. This requires less capillary force to pull water back from the cold end to the hot end, reducing the resistance to water recirculation between adjacent water storage areas along the cold-to-hot direction. Therefore, through-holes 32 of this specification allow for both high water vapor transmittance and sufficiently low resistance to water recirculation. The well-spaced water vapor transmission and recirculation effects accelerate the heat transfer circulation to the heat source and improve the heat dissipation effect of the heat spreader.

[0133] In some specific embodiments, the foil 31 is also provided with at least one guide groove 34 that extends through the foil 31 along the thickness direction.

[0134] It should be noted that the guide groove 34 is far from the hot end of the heat spreader and close to the cold end of the heat spreader. Since the groove size of the guide groove 34 is much larger than that of the through hole 32, the resistance of water vapor passing through the guide groove 34 is small and the permeability is high. This allows the water vapor to be quickly pushed to the cold end for condensation under the action of pressure difference, further accelerating the heat conduction cycle of condensation into water and reflux, improving the heat conduction and heat dissipation effect of the heat spreader, and accelerating the heat dissipation at the heat source.

[0135] In some specific embodiments of the second aspect, the first side of the foil 31 includes a first region and a second region. The density of through holes 32 in the first region is greater than the density of through holes 32 in the second region. It should be noted that the first region is close to the hot end.

[0136] This makes the aperture of the through hole 32 in the first region smaller than that in the second region, allowing more water to be stored in the water storage area under the action of capillary force to conduct heat and dissipate heat from the heat source.

[0137] In some embodiments, the first cover plate 1 includes a first copper cover plate and a first aluminum cover plate stacked together; the second cover plate 2 includes a second aluminum cover plate and a second copper cover plate stacked together.

[0138] The first aluminum cover plate has a first aluminum surface and a first aluminum back surface arranged opposite to each other along the thickness direction, and the first copper cover plate has a first copper surface and a first copper back surface arranged opposite to each other along the thickness direction. The first aluminum surface and the first copper back surface are attached together, and a portion of the first copper surface is recessed into the first cover plate 1 to form a first groove 13.

[0139] The second aluminum cover plate has a second aluminum surface and a second aluminum back surface that are arranged opposite to each other along the thickness direction. The second copper cover plate has a second copper surface and a second copper back surface that are arranged opposite to each other along the thickness direction. The second aluminum back surface and the second copper surface are attached together. Part of the second aluminum surface is recessed into the second cover plate 2 to form multiple rows of protrusions 23. A second groove 24 is formed between two adjacent rows of protrusions.

[0140] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention.

[0141] A water absorption test was conducted on the novel capillary structure and the traditional woven wire mesh to test their climbing speed. The test method is as follows: The novel capillary structure and the woven wire mesh were respectively resistively welded to the same designated area on a steel sheet with a length of 180mm, a width of 70mm, and a thickness of 10mm (within the designated area, the novel capillary structure and the woven wire mesh correspond one-to-one with the steel sheet in the length and width directions respectively), and the test product was obtained.

[0142] The test product is suspended at one end along the length of the steel sheet, serving as the top, and the other end as the bottom (at this time, the top and bottom of the new capillary structure and the traditional woven wire mesh are at the same height along the length of the steel sheet). The test product is then sent into the water along the length of the steel sheet using a lifting device. Timing begins after the bottom of the test product contacts the water. The time taken for the water to rise from the bottom of the test product to the top of the test product (i.e., along the length of the steel sheet) is recorded to represent the rising speed of the new capillary structure and the woven wire mesh.

[0143] This test involved six water absorption tests on the aforementioned products, and the average climbing speed was calculated for each test.

[0144] Example 1

[0145] The dimensional parameters of the novel capillary structure are as follows:

[0146] The foil 31 is made of stainless steel, with a thickness T1 of 0.01 mm, a length of 150 mm, and a width of 50 mm. The through-holes 32 are circular and arranged in a rectangular array. The diameter D of the through-holes is 0.06 mm. The distance H between the centers of two adjacent through-holes 32 is 0.12 mm. The thickness T of the novel capillary structure is 0.035 mm, and the thickness T2 of the annular protrusion 33 is 0.025 mm.

[0147] It should be noted that the number of through holes 32 is based on the diameter and spacing of the through holes, and is set to the maximum extent along the length and width directions of the foil.

[0148] Example 2

[0149] The dimensional parameters of the novel capillary structure are as follows:

[0150] The foil 31 is made of stainless steel, with a thickness T1 of 0.01 mm, a length of 150 mm, and a width of 50 mm. The through-holes 32 are circular and arranged in a rectangular array. The diameter D of the through-holes is 0.1 mm. The distance H between the centers of two adjacent through-holes 32 is 0.25 mm. The thickness T of the novel capillary structure is 0.035 mm, and the thickness T2 of the annular protrusion 33 is 0.025 mm.

[0151] It should be noted that the number of through holes 32 is based on the diameter and spacing of the through holes, and is set to the maximum extent along the length and width directions of the foil.

[0152] Comparative Example 1

[0153] Stainless steel woven wire mesh with a length of 150mm, a width of 50mm, a thickness of 0.06mm, and a mesh count of 250.

[0154] Comparative Example 2

[0155] Stainless steel woven wire mesh with a length of 150mm, a width of 50mm, a thickness of 0.065mm, and a mesh count of 400.

[0156] The test data for Examples 1-2 and Comparative Examples 1-2 are shown in Table 1.

[0157] Table 1: Climb speed test data for the examples and comparative examples

[0158] First climb speed 25s 32s 53s 36s Second climb speed 24s 30s 49s 48s Third climb speed 23s 35s 52s 37s Fourth climb speed 28s 33s 45s 37s Fifth climb speed 19s 32s 53s 52s Sixth climb speed 22s 30s 55s 48s Average climb rate 24s 32s 51s 43s

[0159] As can be seen from the above embodiments and comparative examples, the climbing speed of the novel capillary structure of this application is faster than that of the traditional woven wire mesh, indicating that it has greater capillary force and better capillary effect. When applied to a heat exchanger, it can not only achieve the ultra-thinness of the heat exchanger, but also significantly improve the heat conduction and heat dissipation effect of the heat exchanger.

[0160] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the invention without departing from the principles and spirit of the invention, and all such changes should fall within the protection scope of the claims of the present invention.

Claims

1. A novel method for processing capillary structures, characterized in that, Includes the following steps: A foil of a certain thickness is provided, the foil having a first side and a second side opposite to each other along the thickness direction; Along the thickness direction, a laser beam is used to sequentially penetrate the first and second surfaces of the foil to form multiple spaced through holes on the foil; and each through hole is located at the edge of the second surface of the foil, correspondingly forming an annular protrusion around the edge, thus obtaining a novel capillary structure; Each of the annular protrusions corresponds one-to-one with each of the through holes.

2. The processing method according to claim 1, characterized in that, The arrangement of multiple through holes can be in a rectangular array, a ring array, or an unequal-spacing array.

3. The processing method according to claim 1, characterized in that, The foil has a thickness of 0.005–0.015 mm; and / or The thickness of the novel capillary structure is 0.02–0.05 mm.

4. The processing method according to claim 1, characterized in that, The diameter of the through hole is 0.02–0.15 mm; and / or The distance between the centers of two adjacent through holes is 0.04 to 0.3 mm.

5. A novel capillary structure, characterized in that, include: A foil has a first side and a second side opposite each other along the thickness direction; the foil has a plurality of through holes penetrating the foil along the thickness direction; Each through-hole is located at the edge of the second side of the foil, corresponding to an annular protrusion formed around the edge. Each of the annular protrusions corresponds one-to-one with each of the through holes.

6. The novel capillary structure according to claim 5, characterized in that, The foil is also provided with at least one guide groove that extends through the foil along the thickness direction.

7. The novel capillary structure according to claim 5, characterized in that, The first side of the foil includes a first region and a second region; The density of through holes in the first region is greater than the density of through holes in the second region; and / or The diameter of the through hole in the first region is smaller than the diameter of the through hole in the second region.

8. The novel capillary structure according to any one of claims 5, characterized in that, The shape of the through hole includes one or more of the following: polygonal, circular, elliptical, and teardrop-shaped.

9. A heat spreader, the heat spreader having a hot end in contact with a heat source and a cold end away from the heat source, and a first direction pointing from the hot end to the cold end and a second direction perpendicular to the first direction, characterized in that, The novel capillary structure obtained by applying the processing method of any one of claims 1-4 or the novel capillary structure of any one of claims 5-8, wherein the heat spreader comprises: A first cover plate has a first surface and a first back surface disposed opposite to each other along the thickness direction. The first cover plate is provided with a first groove, which is formed by a portion of the first surface recessing into the interior of the first cover plate. The second cover plate has a second surface and a second back surface that are disposed opposite to each other along the thickness direction. The second cover plate is provided with multiple rows of support protrusions that are spaced apart along the second direction. A second groove is formed between two adjacent rows of support protrusions. The support protrusions are formed by a portion of the second surface recessed into the interior of the second cover plate. A novel capillary structure is fitted into the first groove of the first cover plate, wherein the annular protrusion is located on the bottom wall of the first groove, and a water return passage is formed between two adjacent annular protrusions and the bottom wall of the first groove. The first surface of the first cover plate and the second back surface of the second cover plate are covered together, and the first cover plate and the second cover plate are fixedly connected to form a closed inner cavity between the first cover plate and the second cover plate. The closed inner cavity is used to accommodate the novel capillary structure and the cooling medium of the heat exchange plate. The support protrusion abuts against the novel capillary structure, wherein the support protrusion abuts against the first surface of the foil.

10. The temperature distribution plate according to claim 9, characterized in that, When the first and second cover plates are made of stainless steel or titanium, the novel capillary structure is made of stainless steel; or When the first cover plate and the second cover plate are made of copper, copper-aluminum composite, or copper-steel composite material, the novel capillary structure is made of copper; or When the first cover plate and the second cover plate are made of titanium, the novel capillary structure is also made of titanium.

11. The temperature distribution plate according to claim 9, characterized in that, The first cover plate includes a first copper cover plate and a first aluminum cover plate stacked together; the second cover plate includes a second aluminum cover plate and a second copper cover plate stacked together. The first aluminum cover plate has a first aluminum surface and a first aluminum back surface disposed opposite to each other along the thickness direction, and the first copper cover plate has a first copper surface and a first copper back surface disposed opposite to each other along the thickness direction. The first aluminum surface and the first copper back surface are attached together, and a portion of the first copper surface is recessed into the first cover plate to form the first groove. The second aluminum cover plate has a second aluminum surface and a second aluminum back surface arranged opposite to each other along the thickness direction. The second copper cover plate has a second copper surface and a second copper back surface arranged opposite to each other along the thickness direction. The second aluminum back surface and the second copper surface are attached to each other. A portion of the second aluminum surface is recessed into the second cover plate to form multiple rows of support protrusions. The second groove is formed between two adjacent rows of support protrusions.

12. The temperature distribution plate according to claim 9, characterized in that, The support protrusion does not contact the inner wall of the first groove.

13. The temperature distribution plate according to claim 9, characterized in that, The depth of the second groove is less than the depth of the first groove.

14. The temperature distribution plate according to claim 9, characterized in that, The thickness of the novel capillary structure is less than the depth of the second groove.

15. The temperature distribution plate according to claim 11, characterized in that, The thickness of the first copper cover plate is 0.005-0.1 mm, the thickness of the first aluminum cover plate is 0.01-0.1 mm, the thickness of the second copper cover plate is 0.005-0.1 mm, and the thickness of the second aluminum cover plate is 0.01-0.1 mm.

Images