Miniature heat dissipation device

Abstract

The invention relates to the technical field of piezoelectric fans, in particular to a miniature heat dissipation device which comprises an actuator, and the actuator comprises a base plate, fan blades arranged on the base plate and a vibration element fixed to the fan blades and used for driving the fan blades to vibrate; the supporting structure at least comprises a lower support arranged on one side of the actuator, and the lower support is of a frame-shaped structure and abuts against the base plate; the air outlet plate is arranged on the side, away from the actuator, of the lower support, an output cavity is formed among the base plate, the lower support and the air outlet plate, and an air outlet communicated with the output cavity is formed in the air outlet plate; each fan blade comprises a fixed edge connected with the base plate, a cantilever edge away from the fixed plate and swing edges arranged on the two sides, first gaps are formed between the swing edges and the base plate, second gaps are formed between the swing edges and the inner wall of the lower support, and the distance between the second gaps is smaller than that between the first gaps. Through cooperation of the fan blades and the lower support, gas backflow can be reduced, and the heat dissipation efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of piezoelectric fans, and in particular to a micro heat dissipation device. Background Art

[0002] As electronic devices become increasingly portable and miniaturized, the problem of heat accumulation inside them has become increasingly prominent. Existing heat dissipation devices usually rely on motor drives, which are not only large in size and noisy, but also have high energy consumption and are not suitable for long-term and efficient operation.

[0003] In the related technology, in order to reduce the volume of the heat dissipation device, a piezoelectric active air-cooling / liquid-cooling heat dissipation solution prepared by micro-electromechanical technology (MEMS) technology is applied, that is, the vibration of the substrate is driven by piezoelectric ceramics to realize the flow of cooling medium to take away the heat. Among them, the liquid cooling solution of the piezoelectric pump has the risk of leakage, making the piezoelectric fan a more universal choice.

[0004] However, current piezoelectric fans still have problems such as severe gas reflux and low air volume, resulting in poor heat dissipation effects. Summary of the invention

[0005] In view of at least one of the above technical problems, the present invention provides a micro heat dissipation device, which adopts structural improvement to improve the heat dissipation effect of the piezoelectric fan.

[0006] According to a first aspect of the present invention, there is provided a micro heat dissipation device, comprising: An actuator, the actuator comprising a substrate, a fan blade disposed on the substrate, and a vibration element fixed on the fan blade for driving the fan blade to vibrate; A support structure, comprising at least a lower support disposed on one side of the actuator, wherein the lower support is a frame-shaped structure and abuts against the substrate; An air outlet plate is arranged on a side of the lower support away from the actuator, an output chamber is formed between the base plate, the lower support and the air outlet plate, and an air outlet connected to the output chamber is provided on the air outlet plate; Among them, the fan blade includes a fixed edge connected to the substrate, a cantilever edge away from the fixed plate, and a swinging edge arranged on both sides, a first gap is formed between the swinging edge and the substrate, and a second gap is formed between the swinging edge and the inner wall of the lower support, and the spacing of the second gap is smaller than the spacing of the first gap.

[0007] Furthermore, the spacing of the second gaps ranges from 20 to 50 μm.

[0008] Furthermore, the support structure further comprises an upper support, the upper support is arranged on a side of the actuator away from the lower support, the upper support is frame-shaped, and abuts against the substrate; It also includes an upper top plate that is closely connected to the upper support. An input chamber is formed between the base plate, the upper support and the upper top plate. The side wall of the input chamber is provided with an air inlet that is connected to the outside.

[0009] Furthermore, the air inlet is arranged on a side of the cantilever edge away from the fan blade and is arranged toward the fixed edge.

[0010] Furthermore, the air inlet is configured to be narrow inside and wide outside.

[0011] Furthermore, at least one side wall of the air inlet along the air inlet direction thereof is in a stepped, inclined or arc-shaped structure.

[0012] Furthermore, the air inlet is opened on the base plate, the upper support and the upper top plate. Or any of the three. Or set it in any two of the three. Or a combination of any two of the three.

[0013] Furthermore, two fan blades are relatively arranged, and the cantilever edges of the two fan blades are relatively close to each other, and the air inlets are respectively arranged on the side of the two fan blades away from the cantilever edges.

[0014] Furthermore, the input chamber also has an isolation plate, which is arranged perpendicular to the upper top plate and is located between the two fan blades. The width of the isolation plate is smaller than the spacing between the two cantilever edges, so as to isolate the input chamber into two independent air inlet chambers.

[0015] Furthermore, the isolation plate is arranged at the bottom of the upper top plate, or is arranged on the base plate, or is formed by splicing plates respectively arranged on the base plate and the bottom of the upper top plate.

[0016] Furthermore, the isolation plate has a guide surface on the side facing the two blades, and the guide surfaces are wide at the top and narrow at the bottom, forming an arc surface or a wedge surface structure.

[0017] Furthermore, a first notch is formed on the surface of the fan piece, the first notch extends in the direction of the fixed edge, and there is at least one first notch arrayed in a direction perpendicular to the fixed edge.

[0018] Further, the first notch is arranged on a side of the fan blade facing the output chamber, the first notch is arranged at a position close to the fixed edge, and the first notch extends from the top of the lower support to the output chamber.

[0019] Furthermore, a hollow cavity is provided inside the fan blade, and the hollow cavity extends along the length direction of the fixed edge and expands in a direction perpendicular to the fixed edge.

[0020] Furthermore, a second slot is provided on the side of the fan blade facing the output chamber. The second slot is provided close to the cantilever edge, extends in a direction parallel to the cantilever edge, and extends in a direction perpendicular to the cantilever edge. The second slot and the bottom of the fan blade close to the cantilever edge form a step structure.

[0021] Furthermore, the vibration element is a piezoelectric ceramic, and the piezoelectric ceramic is arranged on at least one side surface of the fan piece in the thickness direction.

[0022] Furthermore, the vibration elements are arranged on both sides of the fan blade, and the polarities of the two vibration elements are designed to be opposite, so that the deformations of the two vibration elements are opposite.

[0023] Furthermore, a plurality of the vibration elements are arranged adjacent to each other, and a distance between two adjacent vibration elements is smaller than the expansion and contraction deformation amplitude of a single vibration element.

[0024] Furthermore, a jet plate is provided between the lower support and the air outlet plate, and the jet plate has a plurality of jet holes arranged through the jet plate, and the airflow compressed by the fan blade in the output chamber is accelerated by the jet holes and then discharged through the air outlet.

[0025] Furthermore, a jet plate is provided between the lower support and the air outlet plate, and the jet plate has a plurality of jet holes arranged through the jet plate, and the area of ​​the jet hole array is arranged opposite to the second slot, and the airflow compressed by the fan blade in the output chamber is accelerated by the jet holes and discharged through the air outlet.

[0026] Furthermore, the ratio of the arrangement hole spacing s to the hole diameter d of the jet holes satisfies s / d≤5, so that the ejected airflow forms a vortex ring and is discharged.

[0027] Furthermore, the ratio of the arrangement hole pitch s to the aperture d of the jet holes satisfies s / d≤2.5, and the air outlet plate further has an air outlet slot having a width greater than the width of the jet hole array, and the air outlet slot is arranged opposite to the jet holes.

[0028] Furthermore, the hole area of ​​the jet hole facing the fan blade side is larger than the hole area facing the air outlet plate side.

[0029] Furthermore, the air outlet plate also has an air outlet structure connected with the air outlet, the air outlet structure includes a hot air slot arranged opposite to the output chamber, a first detour slot connected with the hot air slot, and an air outlet slot connected with the first detour area, the air outlet is arranged at the other end of the air outlet slot, the air outlet slot and the hot air slot are arranged adjacent to each other, and the wall between the two constitutes a heating wall, and the first detour slot is used to change the direction of the airflow and make the airflow accumulate; Among them, part of the airflow in the air outlet structure is heated by the heating wall in the air outlet slot to form a low-pressure area, and the airflow in the first detour slot accumulates to form a high-pressure area. The pressure difference formed by the high-pressure area and the low-pressure area accelerates the airflow to be discharged outside the air outlet.

[0030] Furthermore, it also includes a second detour groove arranged on the side of the air outlet groove close to the air outlet, one end of the second detour groove is connected to the end of the air outlet groove away from the first detour groove, and the other end of the second detour groove is connected to the air outlet.

[0031] Furthermore, the air outlet structure also has a partition plate arranged along the direction of the air flow.

[0032] Furthermore, the heating wall is arc-shaped, wavy-shaped, sawtooth-shaped, or has a groove arranged toward the air outlet slot and the hot air slot opening.

[0033] Furthermore, the air outlet plate also has an air outlet structure connected with the air outlet, the air outlet structure includes a hot air slot arranged opposite to the jet hole, a first detour slot connected with the hot air slot, and an air outlet slot connected with the first detour area, the air outlet is arranged at the other end of the air outlet slot, the air outlet slot and the hot air slot are arranged adjacent to each other, the wall between the two constitutes a heating wall, and the first detour slot is used to change the direction of the airflow and make the airflow accumulate; Among them, part of the airflow in the air outlet structure is heated by the heating wall in the air outlet slot to form a low-pressure area, and the airflow in the first detour slot accumulates to form a high-pressure area. The pressure difference formed by the high-pressure area and the low-pressure area accelerates the airflow to be discharged outside the air outlet.

[0034] The beneficial effects of the present invention are as follows: by setting the spacing of the second gap between the swinging edge of the fan blade and the inner wall of the lower support to be smaller than the spacing of the first gap between the swinging edge of the fan blade and the substrate, when the fan blade swings, more air is pressed into the output chamber and less airflow escapes from the first gap, thereby suppressing backflow and improving the heat dissipation efficiency of the piezoelectric fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 Schematic diagram of the structure of a micro heat sink in an embodiment of the present invention; Figure 2 In the embodiment of the present invention Figure 1 AA section structural diagram; Figure 3 A top view of a micro heat sink according to an embodiment of the present invention; Figure 4 In the embodiment of the present invention Figure 3 A schematic diagram of the local enlarged structure at B in FIG. Figure 5 A schematic diagram of the three-dimensional structure of a micro heat dissipation device in an embodiment of the present invention; Figure 6 In the embodiment of the present invention Figure 5 A schematic diagram of the local enlarged structure at C in FIG. Figure 7 In the embodiment of the present invention Figure 5 DD section structure schematic diagram; Figure 8 In the embodiment of the present invention Figure 7 A schematic diagram of the local enlarged structure at E in FIG. Fig. 9 A schematic diagram of an airflow escape structure of a top air inlet structure in the related art; Fig.10 is a schematic cross-sectional structural diagram of a micro heat sink in an embodiment of the present invention; Fig.11 It is a schematic diagram of the structure of airflow escape in a micro heat sink in an embodiment of the present invention; Fig.12 In the embodiment of the present invention Fig.10 A schematic diagram of the local enlarged structure at F in FIG. Fig.13 A schematic diagram of a structural deformation of an air inlet in an embodiment of the present invention; Fig.14 is a schematic diagram of another structural deformation of the air inlet in an embodiment of the present invention; Fig.15 Schematic diagram of another structural deformation of the air inlet in an embodiment of the present invention; Fig.16 Schematic diagram of another structural deformation of the air inlet in an embodiment of the present invention; Fig.17 is a schematic diagram of a transverse cross-sectional structure of a micro heat sink in an embodiment of the present invention; Fig.18 In the embodiment of the present invention Fig.17 A schematic diagram of the local enlarged structure at G in FIG. Fig.19 is a schematic diagram of a transverse cross-sectional structure of a micro heat sink in an embodiment of the present invention; Fig. 20 Schematic diagram of the three-dimensional structure of the lower support and the actuator in an embodiment of the present invention; Fig.21 is a partial cross-sectional structural schematic diagram of an actuator and a lower support in an embodiment of the present invention; Fig. 22 is a schematic cross-sectional structural diagram of an actuator and a lower support in an embodiment of the present invention; Fig.23 It is a schematic cross-sectional view of the fan blade and the vibration element in an embodiment of the present invention; Fig.24 Another structural schematic diagram of the fan blade and the vibration element in an embodiment of the present invention; Fig.25 Schematic diagram of the structure of a micro heat sink in an embodiment of the present invention; Fig.26 In the embodiment of the present invention Fig.25 Schematic diagram of the exploded structure of the micro heat sink; Fig. 27 In the embodiment of the present invention Fig.25 Schematic diagram of the cross-sectional structure in the HH direction; Fig.28 In the embodiment of the present invention Fig. 27 A schematic diagram of the local enlarged structure at J in FIG. Fig.29 It is a spray simulation diagram of jet holes with different spacings in an embodiment of the present invention; Fig.30 Schematic diagram of the three-dimensional structure of the air outlet plate in an embodiment of the present invention; Fig.31 A schematic diagram of a structural deformation of the air outlet structure in an embodiment of the present invention; Fig.32 A schematic diagram of another structural deformation of the air outlet structure in an embodiment of the present invention; Fig.33 A schematic diagram of a deformed structure of a heating wall in an embodiment of the present invention; Fig.34 It is a schematic diagram of another deformation structure of the heating wall in an embodiment of the present invention; Fig.35 It is a schematic diagram of another deformation structure of the heating wall in an embodiment of the present invention; Fig.36 Schematic diagram of the exploded structure of the micro heat sink in the embodiment of the present invention.

[0037] Explanation of the reference numerals: 1. actuator; 11. substrate; 12. fan blade; 121. fixed edge; 122. cantilever edge; 123. swing edge; 124. first gap; 125. second gap; 126. first slot; 127. hollow cavity; 128. second slot; 13. vibration element; 2. support structure; 20. output chamber; 21. lower support; 22. upper support; 3. air outlet plate; 31. air outlet; 32. air outlet slot; 33. air outlet structure; 331. hot air slot; 332. first detour slot; 333. air outlet slot; 334. heating wall; 335. second detour slot; 336. partition; 4. upper top plate; 40. input chamber; 40a. air inlet chamber; 41. air inlet; 42. isolation plate; 42a. guide surface; 5. jet plate; 51. jet hole. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0039] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0041] With the growing demand for miniaturization of electronic devices, electronic devices such as mobile phones and laptops are gradually developing in the direction of being lighter and thinner. The existing heat dissipation structure generally dissipates the heat from the heat generating structure by rotating a fan driven by a motor. However, for lighter and thinner devices such as smart phones or tablet computers, this heat dissipation structure is large, noisy, and has high energy consumption, and is not suitable for long-term and efficient operation.

[0042] In the prior art, the piezoelectric pump structure made based on the principle of micro-electromechanical systems can realize the circulation of coolant through the vibration of the diaphragm, and its thickness is relatively thin, but the structure of the piezoelectric pump has the risk of liquid leakage, so the research on piezoelectric fans has become the current research focus. Piezoelectric fans are a kind of five-point drive fans that work based on the characteristics of piezoelectric materials. Its core principle is to utilize the inverse piezoelectric effect of piezoelectric materials, that is, when an electric field is applied, the material deforms. By utilizing the inverse piezoelectric effect of piezoelectric materials, the vibration of piezoelectric materials can be driven by applying alternating voltage. The vibration of the piezoelectric material drives the blades of the cantilever beam structure to vibrate the surrounding air at high frequency to form a local airflow. However, most of the current piezoelectric fans have low air output and serious gas reflux, resulting in poor heat dissipation. Therefore, it is necessary to provide a solution to increase the air output of piezoelectric fans to solve the problem of low air output of the above-mentioned piezoelectric fans.

[0043] Figures 1 to 8 is a diagram depicting an exemplary embodiment of a micro heat sink, such as Figures 1 to 3 As shown, the micro heat sink includes an actuator 1, a support structure 2 and an air outlet plate 3. Figure 1 As shown in FIG. 1 , the actuator 1 includes a substrate 11, a fan blade 12 disposed on the substrate 11, and a vibration element 13 fixed on the fan blade 12 for driving the fan blade 12 to vibrate; when actuated, as shown in FIG. Figure 2 As shown in the figure, the vibration element 13 undergoes telescopic deformation, causing the cantilever end of the fan blade 12 to swing up and down. When the fan blade 12 swings down, the airflow is pressed into the supporting structure 2 below and blown out through the air outlet plate 3; in some embodiments, the fan blade 12 can be integrally formed with the substrate 11, for example, a gap around the fan blade 12 can be cut out by cutting.

[0044] like Figure 2 As shown in the figure, the support structure 2 at least includes a lower support 21 arranged on one side of the actuator 1, and the lower support 21 is a frame-type structure and abuts against the substrate 11; through the frame-type structure of the lower support 21, the frame-type structure provides space for the fan blade 12 to swing down; the air outlet plate 3 is arranged on the side of the lower support 21 away from the actuator 1, and the output chamber 20 is formed between the substrate 11, the lower support 21 and the air outlet plate 3, and the air outlet plate 3 has an outlet 31 connected to the output chamber 20; through such a structural arrangement, the fan blade 12 presses the air into the output chamber 20 when it swings down, and the compressed gas is then discharged through the outlet 31.

[0045] Please refer to Figure 3The fan blade 12 includes a fixed edge 121 connected to the base plate 11, a cantilever edge 122 away from the fixed plate, and swing edges 123 arranged on both sides. A first gap 124 is formed between the swing edge 123 and the base plate 11, and a second gap 125 is formed between the swing edge 123 and the inner wall of the lower support 21. The spacing of the second gap 125 is smaller than the spacing of the first gap 124. Please refer to Figures 4 to 8 In the related art, the inner wall of the frame structure of the lower support 21 is mostly flush with the wall adjacent to the swing edge 123 on the substrate 11, so that the spacing between the first gap 124 and the second gap 125 is the same. In this way, when the fan blade 12 swings downward, a large amount of gas will escape through the first gap 124 between the swing edge 123 on both sides of the fan blade 12 and the substrate 11, so that the air output of the piezoelectric fan is greatly reduced; in an embodiment of the present invention, by protruding the inner wall of the lower support 21 inward, the second gap 125 is smaller than the first gap 124, thereby making the second gap 124 between the swing edge 123 of the fan blade 12 and the inner wall of the lower support 21 The gap 125 is further reduced. Through the setting of this structure, the cross-section of gas escape at the swinging edge 123 of the fan blade 12 is reduced, and the cooperation between the fan blade 12 and the lower support 21 forms a "zero gap" structure on the side; of course, it should be pointed out here that the structure in which the second gap 125 is smaller than the first gap 124 is not limited to the structural form in which the inner wall of the lower support 21 protrudes inward, and the first gap 124 of the swinging edge 123 can also be moved outward when opening, so that the distance between the swinging edge 123 of the fan blade 12 and the inner wall of the lower support 21, that is, the distance of the second gap 125, is as small as possible, thereby reducing gas waste.

[0046] In the above embodiment, by setting the spacing of the second gap 125 between the swinging edge 123 of the fan blade 12 and the inner wall of the lower support 21 to be smaller than the spacing of the first gap 124 between the swinging edge 123 of the fan blade 12 and the substrate 11, when the fan blade 12 swings, more air is pressed into the output chamber 20 and less airflow escapes from the first gap 124, thereby suppressing backflow and improving the heat dissipation efficiency of the piezoelectric fan.

[0047] In some embodiments of the present invention, the width of the first gap 124 can be reduced by high-precision processing such as femtosecond laser or chemical etching, but the spacing of the second gap 125 does not require high processing technology. It is only necessary to reasonably set the relative position relationship between the lower support 21 and the first gap 124. In some embodiments of the present invention, the spacing of the second gap 125 ranges from 20 to 50µm. By setting this range, the size of the second gap 125 will not affect the vibration of the fan blade 12 during the high-frequency vibration of the fan blade 12, and at the same time, the waste of gas can be reduced as much as possible, so that a side structure similar to "zero gap" is formed between the fan blade 12 and the lower support 21, thereby suppressing backflow during the swing of the fan blade 12, ensuring that the airflow is not wasted as much as possible, and improving the airflow efficiency of the fan.

[0048] like Fig. 9 As shown in , the upper part of the fan blade 12 in the related art mostly adopts the top air intake structure, but this top air intake method has obvious defects. On the one hand, the gap between the air inlet and the electronic equipment is too narrow, resulting in a small effective air intake cross-sectional area of ​​the airflow and insufficient air intake. On the other hand, during the upward swing of the fan blade 12, due to its movement toward the top, the return path between the fan blade 12 and the top air inlet 41 is short, which will cause more serious backflow during the upward swing. Fig.10 The figure shows a cross-sectional view of a micro heat sink in an embodiment of the present invention. The support structure 2 also includes an upper support 22, which is arranged on the side of the actuator 1 away from the lower support 21. The upper support 22 is frame-shaped and abuts against the substrate 11. The structure of the upper support 22 is similar to that of the lower support 21, and it provides space for the fan blades 12 to swing upward. It also includes an upper top plate 4 that is closely connected to the upper support 22. The substrate 11, the upper support 22 and the upper top plate 4 form an input chamber 40, and the side wall of the input chamber 40 has an air inlet 41 that is connected to the outside. Fig.11 As shown in the figure, by setting the air inlet 41 on the side instead of the top, the gas return path is greatly lengthened, which increases the barrier to the gas return in the input chamber 40. With this type of structural setting, on the one hand, there is no need to consider the gap between the upper top plate 4 and the electronic equipment, and air can be taken in from the side. On the other hand, the path for the gas return when the fan blade 12 swings upward is extended. By combining the above-mentioned side air intake and the "zero gap" structure on the side of the fan blade 12, the return flow of the fan blade 12 is suppressed during the swinging down and up, thereby further increasing the air output of the micro heat sink.

[0049] Please continue to refer to Fig.10In the embodiment of the present invention, the air inlet 41 is arranged on the side of the cantilever edge 122 away from the fan blade 12 and is arranged toward the fixed edge 121. That is, in the embodiment of the present invention, the air inlet 41 for side air intake is arranged on the side of the fixed edge 121 of the fan blade 12 rather than on the side of the swing edge 123. Through the arrangement of this structure, on the one hand, the gas reflux path is maximized when the fan blade 12 swings upward, and on the other hand, the upward swing of the fan blade 12 can also reduce the gas reflux area, such as Fig.12 As shown in FIG. 1 , the vibration element 13 disposed on the fan blade 12 can block the air inlet 41 to a certain extent when swinging upward.

[0050] In addition, in the embodiment of the present invention, in order to further reduce the backflow of gas, the structure of the air inlet 41 is improved, such as Fig.13 As shown, the air inlet 41 is narrow inside and wide outside. Here, narrow inside and wide outside means that the air inlet 41 has a certain length to form an air inlet channel, and the cross-sectional area of ​​the inner side of the air inlet channel is smaller than the cross-sectional area of ​​the outer side; through the setting of this structural form, it is easier for gas to enter from the outside, but there is a certain resistance when it flows out from the inside; in some embodiments, please refer to Figures 13 to 15 At least one side wall of the air inlet 41 along the air inlet direction is in a stepped, inclined or arc-shaped structure. The stepped, inclined and arc-shaped structures here can be set at the top position shown in the figure, or at the side or bottom position.

[0051] In the embodiment of the present invention, the side wall of the input chamber 40 is composed of the upper top plate 4, the upper support 22 and the base plate 11, so there are many options for the opening position of the air inlet 41, such as Fig.16 As shown in the figure, the air inlet 41 can be opened on the substrate 11, the upper support 22 and the upper top plate 4 at the same time, and can be set on the bottom of the upper top plate 4, the upper support 22 and the top of the substrate 11; in some embodiments, grooves can also be made in the middle and bottom of the upper top plate 4, or slots can be opened in the top, middle or lower part of the upper support 22, or slots can be opened in the top or middle part of the substrate 11; in some embodiments, grooves can also be made at the bottom of the upper top and the top of the upper support 22, or grooves can be made at the bottom of the upper support 22 and the top of the substrate 11; in some embodiments, grooves can also be made in any two of the upper top plate 4, the upper support 22 and the substrate 11 to achieve air intake.

[0052] In the embodiment of the present invention, the number of the blades 12 may be only one, or two may be provided to improve the air intake efficiency. Fig.17As shown in the figure, two blades 12 are arranged relatively, the cantilever edges 122 of the two blades 12 are arranged relatively close, and the air inlet 41 is respectively arranged on the side of the two blades 12 away from the cantilever edge 122. Through such an arrangement, air can be introduced through both sides, thereby increasing the air intake.

[0053] In the embodiment of the present invention, in order to reduce the air flow turbulence when the two blades 12 swing in the input chamber 40, as shown in FIG. Fig.17 and Fig.18 As shown in , the input chamber 40 also has an isolation plate 42, which is arranged perpendicular to the upper top plate 4 and is located in the middle of the two blades 12. The width of the isolation plate 42 is less than the distance between the two cantilever edges 122, so as to isolate the input chamber 40 into two independent air inlet chambers 40a. It should be pointed out here that in some embodiments, the distance between the left and right blades 12 is 100~1500 microns, and the isolation plate 42 is blocked in the middle of the cantilever edges 122 of the two blades 12, and its width is less than the gap between the two. In some embodiments, the isolation plate 42 can be fixed to the bottom of the upper top plate 4, that is, as shown in FIG. Fig.18 As shown in the figure, the isolation plate 42 is vertically fixed to the bottom of the upper top plate 4 and extends downward; in some embodiments, the isolation plate 42 can also be set on the base plate 11. When setting it specifically, the isolation plate 42 can span the outside of the two first gaps 124 and extend vertically upward to contact the bottom of the upper top plate 4; in addition, in some embodiments, it can also be spliced, for example, it can be formed by splicing plates respectively set on the base plate 11 and the bottom of the upper top plate 4. Specifically, when splicing, a protrusion and groove structure can be set between the two plates to achieve splicing, and this structural setting can also play a positioning effect.

[0054] In some embodiments, please refer to Fig.18 The side of the isolation plate 42 facing the two blades 12 has a guide surface 42a, which is wide at the top and narrow at the bottom, forming a curved surface or a wedge-shaped surface structure. The setting of the guide surface 42a on the side of the isolation plate 42 can make the air flow smoother and reduce the impact of turbulence.

[0055] In the embodiment of the present invention, in addition to the above-mentioned structural improvements between the blade 12 and the lower support 21, and the improvements to the input chamber 40 and the air inlet, in order to further increase the air intake, the structural form of the blade 12 and the arrangement of the vibration element 13 are also improved. For details, please refer to Figures 19 to 20: A first notch 126 is also provided on the surface of the blade 12. The first notch 126 extends in the direction of the fixed edge 121, and there is at least one notch 126 arranged in a direction perpendicular to the fixed edge 121. It should be noted that the first notch 126 can be provided on the upper surface of the blade 12 or on the lower surface of the blade 12. The width, depth and position of the first notch 126 can be designed according to the working environment and wind speed requirements of the fan. The provision of the first notch 126 not only reduces the use of materials and the overall weight of the blade 12, but also reduces the rigidity of the blade 12, thereby increasing the swing amplitude of the blade 12 and increasing the air output.

[0056] In some embodiments, Figures 19 to 21 As shown in , the first notch 126 is arranged on the side of the fan blade 12 facing the output chamber 20, the first notch 126 is arranged at a position close to the fixed edge 121, and the first notch 126 extends from the top of the lower support 21 to the output chamber 20. That is, in the embodiment of the present invention, one end of the first notch 126 is at the fixed end of the lower support 21, and the other end crosses the fixed end of the lower support 21 to communicate with the output chamber 20; through the arrangement of this structure, on the basis of increasing the amplitude of the fan blade 12, the volume of the output chamber 20 is further increased, so that the output chamber 20 can accommodate more gas, thereby further increasing the air output.

[0057] In addition, as an improvement of the above structure, Fig. 22 As shown in , in some embodiments, a hollow cavity 127 is further provided inside the fan blade 12, and the hollow cavity 127 extends along the length direction of the fixed edge 121 and expands in a direction perpendicular to the fixed edge 121. The provision of the hollow cavity 127 also reduces the overall weight of the fan blade 12 and the overall rigidity of the fan blade 12, thereby increasing the amplitude of vibration.

[0058] Please continue to refer to Figures 19 to 21 In some embodiments, a second notch 128 is further provided on the side of the fan blade 12 facing the output chamber 20. The second notch 128 is provided near the cantilever edge 122, extends in a direction parallel to the cantilever edge 122, and expands in a direction perpendicular to the cantilever edge 122. The second notch 128 and the bottom of the fan blade 12 near the cantilever edge 122 form a step structure. The second notch 128 is provided to further increase the amplitude of the fan blade 12 at the cantilever edge 122. In addition, the step structure provided on the second notch 128 also enables the second notch 128 to have the effect of suppressing backflow. In the process of the fan blade 12 swinging downward, more airflow is accumulated in the second notch 128. When the fan blade 12 is pressed down to a horizontal state, it can be compressed into the output chamber 20 with a greater pressure.

[0059] Regarding the structural improvement of the vibration element 13, Fig.23 and Fig.24 As shown in , the vibration element 13 is a piezoelectric ceramic, and the piezoelectric ceramic is arranged on at least one side surface of the fan blade 12 in the thickness direction. Fig.23 As shown in , the vibration elements 13 are arranged on both sides of the fan blade 12, and the polarities of the two vibration elements 13 are designed to be opposite, so that the deformations of the two vibration elements 13 are opposite. Fig.23 As shown in , when the piezoelectric ceramic on the upper side contracts, the piezoelectric ceramic on the lower side extends, and the combined force of the piezoelectric ceramics on the upper and lower sides makes the driving force for the fan blade 12 to swing up and down greater, thereby increasing the amplitude of the fan blade 12.

[0060] like Fig.24 As shown in , in some embodiments, a plurality of vibrating elements 13 are arranged adjacent to each other, and the distance between two adjacent vibrating elements 13 is smaller than the extension and contraction amplitude of a single vibrating element 13. Through this physically series structure, the piezoelectric ceramic abuts against the adjacent piezoelectric ceramic when it is extended, and the joint force of the two can provide a greater driving force for the fan blade 12, thereby further increasing the amplitude of the fan blade 12.

[0061] In the above embodiment, by improving the structure of the fan blade 12 and the vibration element 13 in the actuator 1, the fan blade 12 has a larger amplitude and a higher driving force. This structural form makes the driving force of the actuator 1 stronger, and the air intake and air output are also improved. In this way, combined with the improvement of the backflow suppression in the input chamber 40 and the output chamber 20, the overall air output of the micro heat sink is enhanced.

[0062] In some embodiments, in order to further increase the air flow rate of the micro heat sink, Figure 25 to Figure 29 As shown in the figure, there is also a jet plate 5 between the lower support 21 and the air outlet plate 3, and the jet plate 5 has a plurality of jet holes 51 arranged through it. The airflow compressed by the fan blade 12 in the output chamber 20 is accelerated through the jet holes 51 and discharged through the outlet 31. In some embodiments of the present invention, the spacing between the jet holes 51 is about 50 to 200 microns. Through the arrangement of the jet holes 51, the flow area of ​​the gas discharged from the output chamber 20 is reduced. The smaller the flow area, the higher the flow rate. The discharge in the form of jets can increase the flow rate of the gas discharged from the micro heat sink.

[0063] In addition, in some embodiments, in order to further increase the flow rate of the gas flowing out of the jet plate 5, as shown in FIG. Fig.28As shown in the figure, there is also a jet plate 5 between the lower support 21 and the air outlet plate 3, and the jet plate 5 has a plurality of jet holes 51 arranged through, and the area of ​​the jet hole 51 array is arranged opposite to the second notch 128, and the airflow compressed by the fan blade 12 in the output chamber 20 is accelerated by the jet hole 51 and discharged through the air outlet 31. It should be pointed out here that in the embodiment of the present invention, the width of the second groove is slightly larger than the overall distance of the jet hole 51 in the width direction. Through the setting of this structure, the compressed gas in the second groove is pressed into the jet hole 51, thereby making the flow rate of the gas ejected from the jet hole 51 stronger.

[0064] Based on the above embodiment, it is found through research that when the ratio of the arrangement hole spacing s of the jet holes 51 to the hole diameter d satisfies s / d≤5, the jetted airflow forms a vortex ring and is discharged. Fig.29 As shown in , when s / d≤5, the airflow ejected from the jet hole 51 forms a vortex ring near the jet hole 51, and two adjacent vortex rings induce each other, gradually move toward the center line, and finally merge to form a more complex vortex ring structure. Through this synthetic vortex ring structure, the flow rate of the airflow discharge can be further improved.

[0065] Please continue to refer to Fig.29 In the embodiment of the present invention, as the ratio of the hole spacing to the hole diameter becomes smaller and smaller, although the range of the mainstream area of ​​the synthetic jet gradually decreases, the range of its end will gradually expand. According to this phenomenon, in some embodiments, such as Fig.28 As shown in , the ratio of the arrangement hole pitch s of the jet holes 51 to the aperture d satisfies s / d≤2.5, and the air outlet plate 3 also has an air outlet slot 32 with a width greater than the width of the array of the jet holes 51, and the air outlet slot 32 is arranged opposite to the jet holes 51. Through the structural form of the wider air outlet slot 32 on the air outlet plate 3, the airflow contacts the air outlet plate 3 with a larger contact area, so that more heat is taken away, thereby improving the overall heat dissipation efficiency.

[0066] In some embodiments, in order to further increase the flow rate of the jet hole 51, as Fig.28 As shown in the figure, the hole area of ​​the jet hole 51 facing the fan blade 12 is larger than the hole area facing the air outlet plate 3. That is, the jet hole 51 is in a structure that is wide at the top and narrow at the bottom. This type of structural design can not only further increase the flow rate of the jet flowing out of the jet hole 51, but also provide a backflow suppression effect due to its narrow lower structure. Through the above-mentioned flow rate increase and heat exchange area increase, combined with the above-mentioned flow increase and backflow suppression structure, the overall heat dissipation efficiency of the micro radiator can be further improved.

[0067] In the embodiment of the present invention, the structure of the air outlet plate 3 is also improved. Fig.30As shown in the figure, the air outlet plate 3 also has an air outlet structure connected with the air outlet 31, and the air outlet structure includes a hot air slot 331 arranged opposite to the output chamber 20, a first detour slot 332 connected with the hot air slot 331, and an air outlet slot 333 connected with the first detour area. The air outlet 31 is arranged at the other end of the air outlet slot 333, and the air outlet slot 333 is adjacent to the hot air slot 331. The wall between the two constitutes a heating wall 334. The first detour slot 332 is used to change the direction of the airflow and accumulate the airflow; the air flowing out of the output chamber 20 The airflow first enters the hot air slot 331, and then flows into the first detour slot 332. In the embodiment of the present invention, the first detour slot 332 allows the airflow to accumulate in the first detour slot 332 to form a higher air pressure by changing the direction and increasing the space for gas accumulation; and part of the airflow in the air outlet structure is heated by the heating wall 334 in the air outlet slot 333 to form a low-pressure area, and the airflow in the first detour slot 332 accumulates to form a high-pressure area. The pressure difference formed by the high-pressure area and the low-pressure area accelerates the airflow to be discharged outside the air outlet 31. This structural form is similar to a chimney structure. By heating the gas in the air outlet slot 333, the air pressure in the air outlet slot 333 is reduced, and then a pressure difference is formed with the relatively high air pressure accumulated in the first detour slot 332. The pressure gradient will press the gas in the first detour slot 332 into the air outlet slot 333, and the airflow is actively accelerated by the heat on the heat dissipation structure that needs to be dissipated, thereby further increasing the flow rate of the gas.

[0068] In some embodiments, please refer to Fig.31 More pressure gradients can also be set, for example, a second detour groove 335 is provided on the side of the air outlet groove 333 close to the air outlet 31, one end of the second detour groove 335 is connected to the end of the air outlet groove 333 away from the first detour groove 332, and the other end of the second detour groove 335 is connected to the air outlet 31. Through such an arrangement, a pressure gradient is formed between the first detour groove 332 and the air outlet groove 333, and the airflow flowing from the air outlet groove 333 to the second detour groove 335 forms an airflow accumulation. Since the air outlet 31 is connected to the outside, a pressure gradient is formed relative to the second detour groove 335, so that the flow rate of the gas when it is discharged to the outside is increased. In addition, the pressure difference formed by the structural setting of the second detour groove 335 can better avoid the gas reflux phenomenon at the air outlet plate 3; its principle is similar to that of a one-way valve. The pressure difference at the second detour groove 335 makes the airflow flow only toward the outside. When there is a reverse reflux suction force, the backflow of the gas is hindered due to the existence of the pressure difference, thereby further suppressing the reflux phenomenon.

[0069] In an embodiment of the present invention, Fig.32As shown in , the air outlet structure also has a partition 336 arranged along the air flow direction. The provision of the partition 336 reduces the flow cross-sectional area of ​​the gas, thereby increasing the flow rate of the gas in the air outlet structure; of course, it should be pointed out here that those skilled in the art can set the width of the partition 336 as needed, for example, the thickness of the partition 336 can be reduced in the detour groove to allow the gas to accumulate better, and the thickness of the partition 336 can be increased at the position of the air outlet 31 to allow the air flow to be discharged in the form of a jet.

[0070] In the embodiment of the present invention, in order to further improve the heating effect of the air outlet slot 333, the structural form of the heating wall 334 can be improved so that the contact area between the heating wall 334 and the air outlet slot 333 and the hot air slot 331 is larger. Figure 33 to Figure 35 As shown in , in some embodiments, the heating wall 334 is arc-shaped, wavy-shaped, zigzag-shaped, or the heating wall 334 has a groove arranged toward the air outlet slot 333 and the hot air slot 331. By bending or slotting the heating wall 334, the heating area at the air outlet slot 333 is increased, the temperature in the air outlet slot 333 is higher, and the pressure gradient is greater.

[0071] In an embodiment of the present invention, the chimney-type air outlet plate 3 structure can also be combined with the jet plate 5, such as Fig.36 As shown in , the chimney-type air outlet plate 3 structure has been described in detail above, and will not be repeated here. Those skilled in the art can refer to the above for understanding. In an embodiment of the present invention, the air outlet plate 3 also has an air outlet structure connected to the air outlet 31, and the air outlet structure includes a hot air groove 331 arranged opposite to the jet hole 51, a first detour groove 332 connected to the hot air groove 331, and an air outlet groove 333 connected to the first detour area. The air outlet 31 is arranged at the other end of the air outlet groove 333, and the air outlet groove 333 is arranged adjacent to the hot air groove 331. The wall between the two constitutes a heating wall 334, and the first detour groove 332 is used to change the direction of the air flow and accumulate the air flow; part of the air flow in the air outlet structure is heated by the heating wall 334 in the air outlet groove 333 to form a low-pressure area, and the air flow in the first detour groove 332 accumulates to form a high-pressure area. The pressure difference formed by the high-pressure area and the low-pressure area accelerates the air flow to be discharged outside the air outlet 31.

[0072] It should be pointed out here that the micro heat dissipation device in the embodiment of the present invention is applied to the heating structure of the electronic device, and the heat dissipation can be carried out in the form of the air outlet plate 3 being fitted with the heating structure. The heating structure can specifically be a semiconductor component, such as an integrated circuit board, etc.; in some embodiments, the heating structure can be a chip package formed by a processor or other integrated circuits; in some embodiments, the heating structure can also be a sensor, an optical device, a battery, etc. Electronic devices include but are not limited to smart phones, tablet computers, handheld gaming devices, digital cameras, headphones or other thin and light devices, etc. When the heat is specifically dissipated, the vibration element 13 drives the vibration of the fan blade 12, so that the fan blade 12 compresses the gas in the input chamber 40 into the output chamber 20, and discharges it through the outlet 31, while the outside air enters through the inlet 41, and a continuous airflow is formed under the reciprocating vibration of the fan blade 12. Through the above-mentioned improvements, the traditional electric drive structure of the fan has been abandoned. The overall thickness of the micro heat dissipation device can be less than two millimeters, and the operating frequency of the product exceeds 20kHz, which is in the ultrasonic frequency band. It is basically noiseless during operation, has lower energy consumption and can operate for a long time, which not only ensures high response speed but also eliminates noise pollution. Compared with piezoelectric pumps, there is no risk of liquid leakage, providing a quiet and efficient heat dissipation solution for electronic equipment.

[0073] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A micro heat sink, characterized in that: include: An actuator, the actuator comprising a substrate, a fan blade arranged on the substrate, and a vibration element fixed on the fan blade for driving the fan blade to vibrate; A support structure, comprising at least a lower support disposed on one side of the actuator, wherein the lower support is a frame-shaped structure and abuts against the substrate; An air outlet plate is arranged on a side of the lower support away from the actuator, an output chamber is formed between the base plate, the lower support and the air outlet plate, and an air outlet connected to the output chamber is provided on the air outlet plate; Among them, the fan blade includes a fixed edge connected to the substrate, a cantilever edge away from the fixed plate, and a swinging edge arranged on both sides, a first gap is formed between the swinging edge and the substrate, and a second gap is formed between the swinging edge and the inner wall of the lower support, and the spacing of the second gap is smaller than the spacing of the first gap.

2. The micro heat sink according to claim 1, characterized in that: The pitch of the second gap ranges from 20 to 50 µm.

3. The micro heat sink according to claim 1, characterized in that: The support structure further includes an upper support, which is arranged on a side of the actuator away from the lower support, and is frame-shaped and abuts against the substrate; It also includes an upper top plate that is closely connected to the upper support. An input chamber is formed between the base plate, the upper support and the upper top plate. The side wall of the input chamber is provided with an air inlet that is connected to the outside.

4. The micro heat sink according to claim 3, characterized in that: The air inlet is arranged on a side of the cantilever edge away from the fan blade and is arranged toward the fixed edge.

5. The micro heat sink according to claim 3, characterized in that: The air inlet is narrow inside and wide outside.

6. The micro heat sink according to claim 5, characterized in that: At least one side wall of the air inlet along the air inlet direction is in a stepped, inclined or arc-shaped structure.

7. The micro heat sink according to claim 5, characterized in that: The air inlet is opened on the base plate, the upper support and the upper top plate. Or any of the three. Or set it in any two of the three. Or a combination of any two of the three.

8. The micro heat sink according to claim 3, characterized in that: The two fan blades are arranged relatively to each other, the cantilever edges of the two fan blades are arranged relatively close to each other, and the air inlets are respectively arranged on the side of the two fan blades away from the cantilever edges.

9. The micro heat sink according to claim 8, characterized in that: The input chamber also has an isolation plate, which is arranged perpendicular to the upper top plate and is located between the two fan blades. The width of the isolation plate is smaller than the distance between the two cantilever edges, so as to isolate the input chamber into two independent air inlet chambers.

10. The micro heat sink according to claim 9, characterized in that: The isolation plate is arranged at the bottom of the upper plate, or is arranged on the base plate, or is formed by splicing plates respectively arranged on the base plate and the bottom of the upper plate.

11. The micro heat sink according to claim 9, characterized in that: The isolation plate has a guide surface on the side facing the two blades, and the guide surfaces are wide at the top and narrow at the bottom, forming an arc surface or a wedge surface structure.

12. The micro heat sink according to claim 1, characterized in that: A first notch is also formed on the surface of the fan blade. The first notch extends along the direction of the fixed edge, and there is at least one first notch arrayed in a direction perpendicular to the fixed edge.

13. The micro heat sink according to claim 12, characterized in that: The first notch is disposed on a side of the fan blade facing the output chamber, the first notch is disposed at a position close to the fixed edge, and the first notch extends from the top of the lower support to the output chamber.

14. The micro heat sink according to claim 1, characterized in that: A hollow cavity is also provided inside the fan blade, and the hollow cavity extends along the length direction of the fixed edge and expands in a direction perpendicular to the fixed edge.

15. The micro heat sink according to claim 1, characterized in that: A second slot is also provided on the side of the fan blade facing the output chamber. The second slot is provided close to the cantilever edge, extends in a direction parallel to the cantilever edge, and expands in a direction perpendicular to the cantilever edge. The second slot and the bottom of the fan blade close to the cantilever edge form a step structure.

16. The micro heat sink according to claim 1 or 12, characterized in that: The vibration element is a piezoelectric ceramic, and the piezoelectric ceramic is arranged on at least one side surface of the fan piece in the thickness direction.

17. The micro heat sink according to claim 16, characterized in that: The vibration elements are arranged on both sides of the fan blade, and the polarities of the two vibration elements are designed to be opposite, so that the deformations of the two vibration elements are opposite.

18. The micro heat sink according to claim 16, characterized in that: A plurality of the vibration elements are arranged adjacent to each other, and a distance between two adjacent vibration elements is smaller than the expansion and contraction deformation amplitude of a single vibration element.

19. The micro heat sink according to claim 1, characterized in that: A jet plate is also provided between the lower support and the air outlet plate. The jet plate has a plurality of jet holes that are arranged through the jet plate. The airflow compressed by the fan blade in the output chamber is accelerated by the jet holes and then discharged through the air outlet.

20. The micro heat sink according to claim 15, characterized in that: There is also a jet plate between the lower support and the air outlet plate, and the jet plate has a plurality of jet holes arranged through it. The area of ​​the jet hole array is arranged opposite to the second slot, and the airflow compressed by the fan blade in the output chamber is accelerated by the jet holes and discharged through the air outlet.

21. The micro heat sink according to claim 19, characterized in that: The ratio of the arrangement hole spacing s to the hole diameter d of the jet holes satisfies s / d≤5, so that the ejected airflow forms a vortex ring and then is discharged.

22. The micro heat sink according to claim 20, characterized in that: The ratio of the arrangement hole spacing s to the aperture d of the jet holes satisfies s / d≤2.5, and the air outlet plate also has an air outlet slot with a width greater than the width of the jet hole array, and the air outlet slot is arranged opposite to the jet holes.

23. The micro heat sink according to claim 19, characterized in that: The hole area of ​​the jet hole facing the fan blade is larger than the hole area facing the air outlet plate.

24. The micro heat sink according to claim 1, characterized in that: The air outlet plate also has an air outlet structure connected with the air outlet, the air outlet structure includes a hot air slot arranged opposite to the output chamber, a first detour slot connected with the hot air slot, and an air outlet slot connected with the first detour area, the air outlet is arranged at the other end of the air outlet slot, the air outlet slot and the hot air slot are arranged adjacent to each other, and the wall between the two constitutes a heating wall, and the first detour slot is used to change the direction of the airflow and make the airflow accumulate; Among them, part of the airflow in the air outlet structure is heated by the heating wall in the air outlet slot to form a low-pressure area, and the airflow in the first detour slot accumulates to form a high-pressure area. The pressure difference formed by the high-pressure area and the low-pressure area accelerates the airflow to be discharged outside the air outlet.

25. The micro heat sink according to claim 24, characterized in that: It also includes a second detour groove arranged on the air outlet groove near the air outlet, one end of the second detour groove is connected to the end of the air outlet groove away from the first detour groove, and the other end of the second detour groove is connected to the air outlet.

26. The micro heat sink according to claim 24, characterized in that: The air outlet structure also has a partition plate arranged along the direction of the air flow.

27. The micro heat sink according to claim 24, characterized in that: The heating wall is in an arc shape, a wave shape, a sawtooth shape, or has a groove arranged toward the air outlet slot and the hot air slot opening.

28. The micro heat sink according to claim 19, characterized in that: The air outlet plate also has an air outlet structure connected with the air outlet, the air outlet structure includes a hot air slot arranged opposite to the jet hole, a first detour slot connected with the hot air slot, and an air outlet slot connected with the first detour area, the air outlet is arranged at the other end of the air outlet slot, the air outlet slot and the hot air slot are arranged adjacent to each other, and the wall between the two constitutes a heating wall, and the first detour slot is used to change the direction of the airflow and make the airflow accumulate; Among them, part of the airflow in the air outlet structure is heated by the heating wall in the air outlet slot to form a low-pressure area, and the airflow in the first detour slot accumulates to form a high-pressure area. The pressure difference formed by the high-pressure area and the low-pressure area accelerates the airflow to be discharged outside the air outlet.

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