MEMS synthetic jet heat spreader and array heat spreader based on asymmetric dual diaphragm

Abstract

This invention discloses a MEMS synthetic jet heat sink and array heat sink based on an asymmetric dual-diaphragm and a top-surface through-flow channel, comprising a PCB substrate, a silicon substrate, a first piezoelectric diaphragm, a second piezoelectric diaphragm, and a top frame. The lower surface of the PCB substrate is used for mounting to a heat source and is a complete plane; the silicon substrate is disposed on the PCB substrate, and a vibration cavity is formed within the silicon substrate; the first and second piezoelectric diaphragms are sealed and connected to the silicon substrate, and together enclose the vibration cavity; the two piezoelectric diaphragms are arranged asymmetrically relative to the PCB substrate; the top frame is disposed above the first and second piezoelectric diaphragms and connected to the PCB substrate; the top frame has an opening; the opening communicates with the vibration cavity, together forming a top-surface through-flow bidirectional channel, so that the air intake and exhaust processes of the heat sink are completed through the top-surface through-flow bidirectional channel.

Description

Technical Field

[0001] This invention relates to the field of heat dissipation technology for microelectromechanical systems (MEMS), specifically to a MEMS synthetic jet heat sink and array heat sink based on an asymmetric dual-diaphragm and a top-surface through-flow channel. Background Technology

[0002] As electronic devices continue to evolve towards miniaturization, ultra-thinness, and high integration, the power density of chips and devices is constantly increasing, leading to a sharp rise in heat flux density. Traditional passive and conventional active cooling solutions are no longer sufficient to meet the thermal management needs of compact devices. Current mainstream cooling technologies suffer from problems such as large size, high power consumption, complex structure, and insufficient reliability, making them unable to adapt to increasingly stringent space constraints and performance requirements.

[0003] MEMS synthetic jet cooling technology has become an important development direction for miniaturized active heat dissipation due to its advantages such as no rotating parts, compact structure, fast response, and high reliability. However, existing MEMS synthetic jet heat sinks still have obvious technical limitations: most devices adopt a vertical jet structure, where the airflow impacts the heat source surface vertically, which easily forms local high-pressure areas, resulting in a limited effective heat dissipation range, difficulty in covering long strips and distributed heat sources, and poor heat dissipation uniformity; the dual-diaphragm symmetrical structure is prone to airflow collision and eddy current loss, resulting in low energy utilization and difficulty in further improving heat dissipation efficiency.

[0004] Regarding flow channel layout, existing solutions mostly adopt bottom intake, side intake, or bottom-in-top-out structures, requiring air intake gaps and installation space to be reserved at the bottom or side of the device. This makes full-plane mounting impossible and results in poor compatibility in ultra-thin, sealed cavities. Furthermore, bottom openings interfere with heat source and circuit layout, reducing structural sealing and environmental adaptability. In addition, traditional jet solutions have a fixed spray direction, failing to achieve directional, controllable sweeping heat dissipation. This limits their adaptability to complex heat sources, narrow spaces, and asymmetrical layouts, restricting their application in high-density integrated electronic systems. CN107197608A discloses a four-directional piezoelectric heat dissipation module, using four-directional piezoelectric oscillators to drive a rectangular cavity. This complex structure, coupled with its "breathing" airflow circulation relying on one-way valves at the top and bottom, presents a significant challenge in terms of valve reliability and response speed at the microscale.

[0005] In summary, while existing technologies offer solutions to improve jet performance through structural optimization and nozzle design, none have achieved a synergistic design between the unequal-height dual-diaphragm structure and the top-surface through-type bidirectional flow channel. These solutions fail to fundamentally break the flow field symmetry, achieve tilted directional jets without external guide structures, or simultaneously meet the combined requirements of ultra-thin mounting, efficient heat dissipation, and high reliability. Therefore, there is an urgent need for a micro-heat dissipation solution that innovates at the flow field mechanism and structural topology levels to achieve low energy consumption, high heat dissipation efficiency, high reliability, and ultra-thin mounting. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a MEMS synthetic jet heat sink and an array-type heat sink based on an asymmetric dual-diaphragm system. The heat sink aims to fundamentally break the symmetric flow field, avoid airflow collisions, and improve driving efficiency. Simultaneously, it optimizes the flow channel topology, enabling both the intake and jet processes to be completed on the top surface of the device. This allows the bottom of the device to be seamlessly mounted to the heat source, resulting in a compact structure, high heat dissipation efficiency, and reliable operation.

[0007] The first aspect of this invention is to provide a MEMS synthetic jet heat sink based on an asymmetric dual-diaphragm and a top-surface through-flow channel, comprising:

[0008] A PCB substrate having a lower surface for mounting to a heat source, said lower surface being a complete plane;

[0009] A silicon substrate is disposed on the PCB substrate; and a vibration cavity is formed within the silicon substrate.

[0010] The first piezoelectric diaphragm and the second piezoelectric diaphragm are sealed together on the silicon substrate and together form the vibration cavity; the first piezoelectric diaphragm and the second piezoelectric diaphragm are arranged asymmetrically with respect to the PCB substrate;

[0011] A top frame is disposed above the first and second piezoelectric diaphragms and connected to the PCB substrate; the top frame has an opening.

[0012] The opening is connected to the vibration cavity, together forming a top-surface through-type bidirectional flow channel, so that the air intake and exhaust processes of the radiator are completed through the top-surface through-type bidirectional flow channel.

[0013] Furthermore, the sealing connection method is selected from one of adhesive bonding, welding, or bonding.

[0014] Furthermore, the silicon substrate has a high platform and a low platform with a fixed vertical height difference to form the support base for the asymmetrical arrangement; the first piezoelectric diaphragm is sealed to the high platform, and the second piezoelectric diaphragm is sealed to the low platform.

[0015] Furthermore, the vibration cavity includes an upper vibration cavity formed by the first piezoelectric diaphragm, the second piezoelectric diaphragm and the silicon substrate, and a lower buffer cavity formed between the PCB substrate and a bottom frame; the lower buffer cavity is connected to the upper vibration cavity through a microchannel provided on the PCB substrate.

[0016] Furthermore, the first piezoelectric diaphragm and the second piezoelectric diaphragm are respectively provided with an integrally formed first extensional protrusion structure and a second extensional protrusion structure, so as to form an asymmetric effective vibration end mass distribution or spatial position between the first piezoelectric diaphragm and the second piezoelectric diaphragm, thereby achieving an asymmetric arrangement.

[0017] More preferably, the first piezoelectric diaphragm has a first extended protrusion structure on its side facing away from the vibration cavity, and the second piezoelectric diaphragm has a second extended protrusion structure on its side facing the vibration cavity.

[0018] More preferably, the first and second extensional protrusions have the same outline and weight.

[0019] Furthermore, the top frame has an unequal height structure, with the higher part of the top frame covering the first piezoelectric diaphragm and the relatively lower part of the top frame covering the second piezoelectric diaphragm.

[0020] A second aspect of the present invention provides an array-type heat sink, the heat sink comprising a plurality of heat sink units arranged in an array, the heat sink unit being the aforementioned MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top surface through-flow channel; all the tilted jets of the heat sink units have the same orientation, and the top surface flow channel openings of all the heat sink units are interconnected.

[0021] The beneficial effects of this invention are as follows:

[0022] High-efficiency directional tilting heat dissipation is achieved: by constructing an asymmetric dual-diaphragm height difference, the traditional symmetrical flow field is broken, and the energy that might have been dissipated by collision is converted into the kinetic energy that drives the airflow to flow laterally, naturally forming a directional tilting jet; the tilting jet can "sweep" along the surface of the heat source, more effectively destroying the thermal boundary layer, expanding the effective heat dissipation area, avoiding local hot spots that may be caused by vertical impact, and significantly improving the heat dissipation uniformity and overall heat exchange efficiency.

[0023] It achieves ultra-high integration and full-plane mounting: The top-side through-type bidirectional flow channel design integrates the air intake and air jet paths into a single diameter on the top surface of the device, completely eliminating the traditional solution of opening air intake holes on the bottom or side of the device. This allows the PCB base plate to be a complete plane without reserving any airflow gaps, greatly improving the space utilization and integration convenience in ultra-thin, high-density electronic devices.

[0024] The asymmetric flow field design of the MEMS synthetic jet heat sink of this invention reduces internal airflow vortex losses, enabling energy to be converted into jet kinetic energy more effectively. This allows the same heat dissipation effect to be achieved with lower drive power consumption, resulting in high energy efficiency. Attached Figure Description

[0025] Figure 1 This is a top view of the first and second piezoelectric diaphragms of the MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel as described in Embodiment 1 of the present invention, wherein the arrows indicate the direction of the inclined jet;

[0026] Figure 2 This is a cross-sectional schematic diagram of the MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel, where the arrows indicate the direction of the inclined jet.

[0027] Figure 3 This is a cross-sectional view of the MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel as described in Embodiment 2 of the present invention.

[0028] Figure 4 This is a top view of the MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel as described in Embodiment 3 of the present invention, wherein the arrow indicates the direction of the inclined jet;

[0029] Figure 5 yes Figure 4 A schematic diagram of the three-dimensional structure;

[0030] Figure 6 This is a cross-sectional view of Embodiment 4 of the present invention, wherein the arrow indicates the direction of the inclined jet.

[0031] Wherein, P: PCB substrate; S: silicon substrate; h1: high platform; h2: low platform; M1: first piezoelectric diaphragm; M2: second piezoelectric diaphragm; M11: first epitaxial protrusion structure; M12: second epitaxial protrusion structure; T: top frame; H: opening; C: vibration cavity; C1: upper vibration cavity; C2: lower buffer cavity; 1: heat dissipation unit; 2: bottom frame. Detailed Implementation

[0032] To make the objectives, technical solutions, beneficial effects, and significant advancements of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings provided in the examples of the present invention. Obviously, all the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] In the description of this application, unless otherwise expressly specified and limited, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more; unless otherwise specified or explained, the terms "connected," "fixed," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] Example 1

[0035] like Figure 2 As shown, a MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel has an overall stacked structure. The bottom layer is a PCB substrate P, which provides mechanical support and electrical interconnection. The lower surface of the PCB substrate P is a complete plane without any openings or channels, which can be directly mounted on the heat source surface to achieve full-plane gapless mounting.

[0036] On the upper surface of the PCB substrate P, a top frame T of unequal height and a silicon substrate S of unequal height are bonded from the outside to the inside, with the top frame T located on the top layer of the heat sink.

[0037] The silicon substrate S is fabricated using a single-crystal silicon monolithic molding process, and a vibration cavity C is formed inside it through an etching process. Furthermore, the top surface of the silicon substrate is processed into a high-level mesa h1 and a low-level mesa h2 with a fixed vertical height difference, forming an asymmetrical support base. The portion of the silicon substrate containing the high-level mesa h1 is the high-level silicon substrate, and the portion containing the low-level mesa h2 is the low-level silicon substrate. A portion of the vibration cavity C is etched inside the silicon substrate containing the high-level mesa h1, providing support and vibration space for the first piezoelectric diaphragm M1; the other portion of the vibration cavity C is etched inside the silicon substrate containing the low-level mesa h2, providing support and vibration space for the second piezoelectric diaphragm M2. The silicon substrate S and the PCB substrate together form a connected vibration cavity C, providing a shared vibration space for the first piezoelectric diaphragm M1 and the second piezoelectric diaphragm M2, ensuring smooth airflow circulation.

[0038] The first piezoelectric diaphragm M1 is bonded to the high mesa h1 of the silicon substrate S, and the second piezoelectric diaphragm M2 is bonded to the low mesa h2 of the silicon substrate S. Because of the height difference between the high mesa h1 and the low mesa h2, the first piezoelectric diaphragm M1 and the second piezoelectric diaphragm M2 also have a height difference, forming a high-low difference diaphragm layout. This height difference creates an asymmetric flow field. The first piezoelectric diaphragm M1 and the second piezoelectric diaphragm M2 have identical structures, both being composite piezoelectric thin film structures. Under electrical signal excitation, they generate reciprocating vibrations, providing the driving force for airflow.

[0039] The bottom of the top frame T is sealed to the upper surface of the PCB substrate P. The top of the top frame T covers the first piezoelectric diaphragm M1 and the second piezoelectric diaphragm M2. A top surface through-flow channel opening H is provided in the middle of the top frame T. The opening H faces the vibration cavity C below and together with the vibration cavity C, they form an integrated flow channel for top surface air intake and top surface air exhaust. The air intake process and the air exhaust process share the same top surface channel, so that the airflow circulation is completely constrained in the space above the heat sink, eliminating the need for bottom or side air intake channels. This eliminates the need for traditional bottom or side air intake structures, allowing the bottom of the heat sink to achieve full-plane tight mounting, significantly improving space utilization and environmental adaptability.

[0040] The sealing connection method is a conventional connection method in the art, such as, but not limited to, adhesive bonding, welding, anodic bonding or eutectic bonding.

[0041] The MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel described in this embodiment is an asymmetric dual-diaphragm heat sink based on a silicon substrate with unequal heights. The different heights of the silicon substrate create a fixed vertical height difference, causing the first piezoelectric diaphragm M1 and the second piezoelectric diaphragm M2, respectively mounted on it, to form an asymmetric layout in the vertical direction. This structure fundamentally breaks the traditional symmetric flow field, allowing the two jets to undergo lateral coupling and vector superposition at the outlet, naturally forming a stable directional inclined jet. It can achieve oblique sweeping heat dissipation on the heat source surface without the need for additional flow guiding structures.

[0042] The operation process of the MEMS synthetic jet heat sink is as follows:

[0043] An AC driving voltage of the same frequency and phase is applied to the first piezoelectric diaphragm M1 and the second piezoelectric diaphragm M2;

[0044] During the intake phase, the first piezoelectric diaphragm M1 and the second piezoelectric diaphragm M2 move synchronously toward the direction away from the PCB substrate P under the action of the driving signal, so that a negative pressure is formed in the vibration cavity C, and external cold air enters the vibration cavity C from the opening H.

[0045] During the ejection phase, the first piezoelectric diaphragm M1 and the second piezoelectric diaphragm M2 move towards the direction closer to the PCB substrate P, and the vibration cavity C is compressed to form positive pressure, causing the airflow to be ejected. Because the initial positions of the first piezoelectric diaphragm M1 and the second piezoelectric diaphragm M2 have a fixed height difference, their compression effect on the air inside the vibration cavity C will also differ in time and space, resulting in the two airflows ejected from the opening H having different velocities and angles. The two airflows undergo lateral coupling and vector superposition at the opening H, forming a... Figure 1 The inclined jet shown is directed toward the second piezoelectric diaphragm M2 to achieve oblique sweeping heat dissipation on the heat source surface.

[0046] Example 2

[0047] like Figure 3 As shown, a MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel has an overall stacked structure, consisting of a PCB substrate P, a silicon substrate, and a top frame from bottom to top. This embodiment is basically the same in structure as Embodiment 1; only the differences will be described below, while the similarities will not be repeated.

[0048] The top frame T has the same top height and no vertical height difference. The silicon substrate S has the same height and no vertical height difference. The first piezoelectric diaphragm M1 and the second piezoelectric diaphragm M2 are respectively bonded to the upper surface of the silicon substrate S, and their vibration ends are located at the vibration cavity C.

[0049] The first piezoelectric diaphragm M1 has a first epitaxial protrusion structure M11 integrally formed on the upper surface of its vibrating end (i.e., the bonding end away from the silicon substrate S) (i.e., the side facing away from the vibration cavity C); the second epitaxial protrusion structure M12 is integrally formed on the lower surface of the vibrating end (i.e., the bonding end away from the silicon substrate S) of the second piezoelectric diaphragm M2 (i.e., the side facing the vibration cavity C). The first epitaxial protrusion structure M11 and the second epitaxial protrusion structure M12 have the same outline and equal weight. The two adopt a structure with the same outline but opposite orientation, which significantly changes the mass distribution and inertia of their free ends. This results in a height difference in the vertical direction between the end faces of the effective vibrating ends of the first piezoelectric diaphragm M1 and the second piezoelectric diaphragm M2 when they are bonded to silicon substrates of equal height.

[0050] The MEMS synthetic jet heat sink described in this embodiment is a MEMS synthetic jet heat sink with a diaphragm epitaxial structure, an isocrystalline silicon substrate, and a bidirectional flow channel through the top surface. The overall structure still retains the core four-layer stacked architecture of "PCB substrate-silicon substrate-dual piezoelectric diaphragm-top frame". Its structure is changed to a silicon substrate with the same height. By forming a height difference by epitaxially forming a differentiated structure on the two diaphragms (the first piezoelectric diaphragm and the second piezoelectric diaphragm), a stable directional tilted jet is still achieved, taking into account both the convenience of structural processing and the directionality of the jet.

[0051] During the operation of the MEMS synthetic jet heat sink, due to the inherent height difference between the vibration ends of the first piezoelectric diaphragm M1 and the second piezoelectric diaphragm M2, the pressure propagation, airflow velocity and ejection angle in the corresponding area of ​​the cavity are differentiated. The two airflows are laterally pulled and vector superimposed at the opening H of the top through-flow channel, and finally naturally form a stable inclined jet toward the second piezoelectric diaphragm M2, realizing oblique sweeping heat dissipation on the heat source surface, achieving the same jet and heat dissipation effect as the basic embodiment.

[0052] Meanwhile, this embodiment retains the core design of a top-through bidirectional flow channel, with the entire intake and exhaust process completed on the top surface of the heat sink. The lower surface of the PCB substrate P remains a complete plane, enabling seamless and tight mounting with the heat source, which meets the integration requirements of ultra-thin, high-density, and compact electronic systems. Furthermore, the overall structure is a fully solid-state structure without rotating parts, with the diaphragm and epitaxial structure integrally formed without additional assembly parts. The structure has excellent sealing performance and operational reliability, and can be mass-produced using MEMS standard processes.

[0053] Example 3

[0054] like Figure 4 and Figure 5 As shown, an array-type heat sink includes multiple heat dissipation units arranged in an array. Each heat dissipation unit 1 is a MEMS synthetic jet heat sink based on an asymmetric dual-diaphragm and a top-surface through-flow channel, as described in Embodiment 1 or 2. All heat dissipation units 1 are controlled by a unified driving circuit and operate synchronously. Furthermore, the tilted jets of all heat dissipation units 1 have the same direction, thereby forming a directional tilted jet above the heat source. This achieves comprehensive, uniform, and efficient heat dissipation for large-size chips or distributed heat sources, significantly improving the overall heat dissipation flux and solving the problem of limited heat dissipation capacity of single devices.

[0055] Furthermore, the top surface flow channel openings H of all heat dissipation units 1 are connected, such as... Figure 5 As shown, the interconnected vibrating cavity C and the top flow channel opening H of the arrayed heat dissipation units enable the airflow of each unit to couple synergistically within the cavity, avoiding gap interference and airflow collision when multiple heat dissipation units are spliced ​​together, thereby improving the overall heat dissipation efficiency and uniformity.

[0056] The embodiments described herein treat a single heat sink from Embodiment 1 or Embodiment 2 as a basic functional unit, and arrange it in a two-dimensional array on the PCB substrate P. This achieves a large-scale scaling up of heat dissipation capacity without altering the core structure and working principle of the individual device.

[0057] Example 4

[0058] like Figure 6 As shown, a MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel is disclosed. The heat sink is a MEMS synthetic jet heat sink device with dual diaphragms of unequal height and a top-surface through-flow bidirectional channel. The core retains the design logic of "unequal height dual diaphragms + top-surface through-flow channel". Based on the heat sink described in Example 1, a lower buffer cavity C2 is added at the bottom of the original vibration cavity. The upper vibration cavity C1 and the lower buffer cavity C2 are interconnected through a reserved microchannel to form a double-layer structure of "upper vibration cavity + lower buffer cavity", which further optimizes the airflow stability and heat dissipation uniformity.

[0059] In this embodiment, a top frame T and a bottom frame 2 of unequal height are bonded to the upper surface of a PCB substrate P. The bottom frame 2 is located inside the enclosure formed by the top frame T and the PCB substrate P, and the bottom frame 2 and the PCB substrate P together form a lower buffer cavity C2. Furthermore, the lower buffer cavity C2 has a microchannel (or through-hole) with an upper opening that communicates with the upper cavity. The lower buffer cavity C2 acts as an "air container" to buffer and absorb the periodic pressure pulsations generated by the upper cavity during vibration, thereby stabilizing the flow field.

[0060] The lower buffer cavity C2 is bonded to a silicon substrate S. The top surface of the silicon substrate is processed into a high mesa h1 and a low mesa h2 with a fixed vertical height difference. A first piezoelectric diaphragm M1 is sealed and connected to the high mesa h1 of the silicon substrate S, and a second piezoelectric diaphragm M2 is sealed and connected to the low mesa h2 of the silicon substrate S. The upper vibration cavity C1 is formed inside the silicon substrate S through an etching process, providing a common vibration space for the first piezoelectric diaphragm M1 and the second piezoelectric diaphragm M2, which is the core area for jet formation. The lower buffer cavity C2 is added between the heat sink and the bottom frame described in Embodiment 1, and is connected to the upper vibration cavity C1 through a microchannel on the PCB substrate. As a pressure buffer and flow field stabilization unit, it can effectively suppress the pressure pulsation caused by diaphragm vibration, avoid violent airflow fluctuations, and improve jet stability and heat dissipation uniformity. The parts that are the same as in Embodiment 1 will not be described again.

[0061] During operation, the first piezoelectric diaphragm M1 and the second piezoelectric diaphragm M2, which are of unequal height, reciprocate under the action of the driving signal, causing periodic pressure changes in the upper vibration cavity C1. The lower buffer cavity C2 exchanges gas with the upper vibration cavity C1 through the connecting channel, buffering the pressure peaks and valleys, making the airflow output more stable. At the same time, the height difference between the first piezoelectric diaphragm M1 and the second piezoelectric diaphragm M2 causes the airflow in the upper vibration cavity C1 to form an asymmetric flow field, which undergoes lateral coupling and vector superposition at the opening H of the top through-flow channel, ultimately forming a stable and controllable directional tilted jet. Compared with the single cavity structure described in Example 1, the jet direction is more uniform, the pressure fluctuation is smaller, and the long-term working reliability is higher.

[0062] Meanwhile, this embodiment still retains the core design of the top-surface through-type bidirectional flow channel. The air intake and exhaust processes are mainly completed on the top surface of the device, and the lower surface of the PCB substrate remains a complete plane, which can achieve gapless and tight mounting with the heat source and adapt to the integration requirements of ultra-thin and hermetic electronic devices.

[0063] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in the embodiments can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel, characterized in that... Includes a PCB substrate (P), a silicon substrate (S), a first piezoelectric diaphragm (M1), a second piezoelectric diaphragm (M2), and a top frame (T): The PCB substrate (P) has a lower surface for mounting to a heat source, and the lower surface is a complete plane; The silicon substrate (S) is disposed on the PCB substrate (P); and a vibration cavity (C) is formed within the silicon substrate (S). The first piezoelectric diaphragm (M1) and the second piezoelectric diaphragm (M2) are sealed and connected to the silicon substrate (S) and together form the vibration cavity (C); the first piezoelectric diaphragm (M1) and the second piezoelectric diaphragm (M2) are arranged asymmetrically relative to the PCB substrate (P); and at least the vibration end of the first piezoelectric diaphragm (M1) and the vibration end of the second piezoelectric diaphragm (M2) have a vertical height difference; The top frame (T) is disposed above the first piezoelectric diaphragm (M1) and the second piezoelectric diaphragm (M2) and is connected to the PCB substrate (P); the top frame (T) is provided with an opening (H); wherein the opening (H) is connected to the vibration cavity (C) and together they form a top-surface through-type bidirectional flow channel, so that the air intake and exhaust processes of the heat sink are completed through the top-surface through-type bidirectional flow channel.

2. The MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel according to claim 1, characterized in that, The silicon substrate (S) has a high platform (h1) and a low platform (h2) with a fixed vertical height difference to form the support base for the asymmetrical arrangement; the first piezoelectric diaphragm (M1) is sealed to the high platform (h1), and the second piezoelectric diaphragm (M2) is sealed to the low platform (h2).

3. The MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel according to claim 2, characterized in that, The sealing connection method is selected from adhesive bonding, welding, or bonding.

4. The MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel according to claim 1, characterized in that, The vibration cavity (C) includes an upper vibration cavity (C1) formed by the first piezoelectric diaphragm (M1), the second piezoelectric diaphragm (M2) and the silicon substrate (S), and a lower buffer cavity (C2) formed between the PCB substrate (P) and a bottom frame (2); the lower buffer cavity (C2) is connected to the upper vibration cavity (C1) through a microchannel provided on the PCB substrate (P).

5. The MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel according to claim 3, characterized in that, The first piezoelectric diaphragm (M1) and the second piezoelectric diaphragm (M2) are respectively provided with an integrally formed first epitaxial protrusion structure (M11) and a second epitaxial protrusion structure (M12) to form an asymmetrical vertical height difference at the vibration ends of the first piezoelectric diaphragm (M1) and the second piezoelectric diaphragm (M2).

6. The MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel according to claim 5, characterized in that, The first piezoelectric diaphragm (M1) has a first extended protrusion structure (M11) on its side facing away from the vibration cavity (C), and the second piezoelectric diaphragm (M2) has a second extended protrusion structure (M12) on its side facing the vibration cavity (C).

7. The MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel according to claim 5, characterized in that, The first extensional protrusion (M11) and the second extensional protrusion (M12) have the same outline and weight.

8. The MEMS synthetic jet heat sink based on asymmetric dual diaphragms and a top-surface through-flow channel according to claim 3, characterized in that, The top frame (T) has an uneven top height, with the higher part of the top frame (T) covering the first piezoelectric diaphragm (M1) and the relatively lower part of the top frame (T) covering the second piezoelectric diaphragm (M2).

9. An array-type heat sink, characterized in that, The array-type heat sink includes a plurality of heat sink units (1) arranged in an array. The heat sink unit (1) is a MEMS synthetic jet heat sink based on an asymmetric dual diaphragm and a top surface through-flow channel according to any one of claims 1-8. The inclined jets of all the heat sink units (1) have the same orientation, and the openings (H) of all the heat sink units (1) are connected.

Images