A kind of oscillating vibrator type piezoelectric micro pump and its driving and preparation method

Abstract

The present invention provides an oscillating oscillator piezoelectric micropump and a driving and manufacturing method thereof; the piezoelectric micropump comprises a supporting structure, a first flow layer and a second flow layer arranged at both ends of the supporting structure, and an actuator arranged in the supporting structure. The actuator comprises two actuating units arranged in parallel. The actuating unit comprises a substrate and a vibration element. The vibration element is fixed on the substrate; the two actuating units in the present invention are in a cantilever structure arranged in parallel and on opposite sides, and the central stress similar to that of a conventional annular actuator structure will not be generated during the oscillating pumping process, which helps to extend the service life of the piezoelectric micropump. At the same time, when different excitation signals are input to the two actuating units, the two actuating units can be made to vibrate asynchronously, thereby generating a reverse airflow with a certain degree of continuity in the piezoelectric micropump, thereby playing a role in periodic self-cleaning of the air inlet, and realizing long-term continuous operation of the piezoelectric micropump in a complex environment.

Description

Technical Field

[0001] The invention belongs to the technical field of piezoelectric gas micro pumps, and in particular relates to an oscillating oscillator type piezoelectric micro pump and a driving and manufacturing method thereof. Background Art

[0002] Driven by Generative AI (GAI) technology, the heat problem associated with smartphones is difficult to solve by relying solely on passive cooling technology. The piezoelectric active air-cooling / liquid-cooling solution prepared using micro-electromechanical technology (MEMS) can solve this problem well. Among them, the liquid cooling pump is far less universal than the air cooling solution due to the risk of liquid leakage.

[0003] Traditional active air cooling devices are limited in their application in mobile phones due to their large thickness and high power consumption. In addition, traditional fans have some other disadvantages, such as high noise, which affects the user experience; mechanical parts are easy to wear, resulting in a short life; and it is difficult to achieve precise air volume control, and it is impossible to dynamically adjust according to the actual heat dissipation needs of the device. Traditional piezoelectric micropump structures are mostly fixed on all sides, and the central membrane layer has a high residual stress, which reduces its vibration.

[0004] The patent application with publication number "CN117028214A" provides a piezoelectric pump vibration substrate structure and a piezoelectric micropump, which adopts a four-sided fixed type solution as the vibrator of the piezoelectric micropump; it is necessary to etch support beams and other structures on the surface of the piezoelectric vibrator to further release the influence of residual stress on the vibration of the device, which makes the preparation of this vibrator limited by process steps (it is necessary to etch support beams and other structures), and is not conducive to its further miniaturization and arraying. Summary of the invention

[0005] The purpose of the present invention is to propose an oscillating vibrator piezoelectric micropump and its driving and preparation method, so as to achieve more efficient heat dissipation in applications such as electronic device heat dissipation. Combined with micro-nano processing technology, a lower power consumption and more miniaturized device structure can be achieved. Through a specific structure and driving method, the present invention can simultaneously achieve the functions of forward pumping gas heat dissipation and reverse self-cleaning under the excitation of different frequencies, thereby providing continuous and stable heat dissipation output performance.

[0006] In a first aspect, the present invention provides an oscillating oscillator piezoelectric micropump, which includes a support structure, a first flow layer and a second flow layer arranged at both ends of the support structure, and an actuator arranged in the support structure. An input chamber is formed between the actuator and the first flow layer. An output chamber is formed between the actuator and the second flow layer.

[0007] The actuator comprises one or more actuating units; the actuating units comprise a substrate and a vibrating element; the vibrating element is fixed on the substrate; the four edges of the substrate are respectively a fixed edge, a movable edge and two swinging edges; the fixed edge of the substrate of the actuating unit is fixed to the side surface of the inner cavity of the supporting structure;

[0008] A flow gap is formed between the active edge of the substrate of the actuating unit and the inner cavity of the supporting structure, or between the active edges of the substrates of multiple actuating units; air inlets are provided on two edges of the first flow layer parallel to the flow gap; and an air outlet aligned with the flow gap is provided on the second flow layer.

[0009] Preferably, the actuator comprises two actuating units arranged in parallel; the fixed edges of the substrates of the two actuating units are respectively fixed to a group of opposite sides of the inner cavity of the supporting structure; the substrates of the two actuating units; and a flow gap is formed between the movable edges of the substrates of the two actuating units.

[0010] Preferably, a side sealing structure is provided between the swing edge of the substrate and the corresponding inner side wall of the support structure; the side sealing structure seals the gap between the swing edge of the substrate and the inner side wall of the support structure. The side sealing structure is fixed on the swing edge of the substrate and contacts the corresponding inner side wall of the support structure.

[0011] Preferably, the initial width of the flow gap is 1 μm to 10000 μm.

[0012] Preferably, the distance from the center point of the vibration element to the fixed edge of the substrate is 40% to 60% of the distance from the fixed edge of the substrate to the movable edge. The length of the vibration element is 30% to 50% of the distance from the fixed edge of the substrate to the movable edge.

[0013] Preferably, the first flow layer is provided with an inlet concave structure connected to the air inlet on the side close to the actuator. The inlet concave structure and the air inlet together form an inlet gradient flow channel structure with a larger inner portion and a smaller outer portion; the second flow layer is provided with an outlet concave structure connected to the air outlet on the side close to the actuator. The outlet concave structure and the air outlet together form an outlet gradient flow channel structure with a larger inner portion and a smaller outer portion.

[0014] Preferably, the air intake gradient flow channel structure adopts any one of the following structures:

[0015] Structure 1: The air intake concave structure is provided with one or more stepped planes, so that the air intake gradient flow channel structure is stepped.

[0016] Structure 2: The air intake concave structure is in the shape of an oblique groove, so that the air intake gradient flow channel structure is in the shape of an oblique funnel.

[0017] Structure three: The air intake concave structure is in the shape of an arc-shaped groove, so that the air intake gradient flow channel structure is in the shape of an arc-shaped funnel.

[0018] The outlet gradient flow channel structure adopts any one of the following structures:

[0019] Structure 1: One or more stepped planes are provided on the air outlet concave structure, so that the air outlet gradient flow channel structure is stepped.

[0020] Structure 2: The air outlet concave structure is in the shape of an oblique groove, so that the air outlet gradient flow channel structure is in the shape of an oblique funnel.

[0021] Structure three: The air outlet concave structure is in the shape of an arc-shaped groove, so that the air outlet gradient flow channel structure is in the shape of an arc-shaped funnel.

[0022] Preferably, the side of the second flow layer close to the actuator is in the shape of an inclined plane or a curved surface that gradually approaches the actuator from the air intake gradient flow channel structure to the edges on both sides.

[0023] Preferably, one side of the vibration elements in the two actuating units is commonly grounded, and the other side is respectively connected to an independent power supply control interface.

[0024] In a second aspect, the present invention provides a pumping gas driving method, which uses the aforementioned piezoelectric micropump; the pumping gas driving method includes a forward pumping gas method and a reverse self-cleaning method.

[0025] The forward pumping method is: applying excitation signals of the same frequency and phase to two vibration elements, and the two substrates vibrate synchronously in the same direction under the drive of the vibration elements, driving the air flow to enter from the air inlet, pass through the input chamber, the flow gap and the output chamber, and then be output from the air outlet.

[0026] The reverse self-cleaning method is as follows: different excitation signals are applied to the two vibration elements, the two substrates vibrate asynchronously under the drive of the vibration elements, the gas in the piezoelectric micropump flows in the reverse direction during part or all of the operation time, the air flow enters from the air outlet and is output from the air inlet, and the dust accumulated at the air inlet is removed.

[0027] Preferably, in the forward pumping method and the reverse self-cleaning method, the excitation signal frequency of the vibration element is 10 Hz to 50 MHz. In the reverse self-cleaning method, the frequency difference of the excitation signal input to the two vibration elements is 50 Hz.

[0028] In a third aspect, the present invention provides a method for preparing a piezoelectric micropump, which is used to prepare the aforementioned piezoelectric micropump. It is characterized by:

[0029] The piezoelectric micropump preparation method comprises the following steps:

[0030] Step 1: Processing to obtain a device embryonic body formed by sequentially stacking a substrate, an insulating layer and a structural layer;

[0031] Step 2: Form a vibration element on the structural layer; the preparation method of the vibration element can be either graphical or non-graphic. The graphical method is: forming a piezoelectric layer on the structural layer, and the methods include but are not limited to bonding piezoelectric sheets, magnetron sputtering, PLD (pulsed laser deposition), CVD (chemical vapor deposition), gel method, etc. The piezoelectric layer can be processed in a graphical manner to form a vibration element with a specific pattern. The non-graphic method is to directly cover the processed vibration element on the surface of the structural layer.

[0032] Step 3, forming top electrodes on the two vibration elements;

[0033] Step 4: Etching the middle and both side edges of the structural layer, so that an I-shaped gap is formed in the middle and both sides of the structural layer; the I-shaped gap divides the structural layer into two independent substrates;

[0034] Step 5: a protective layer is provided on the front side of the device obtained in step 5, and the back side of the substrate is etched to form an output chamber;

[0035] Step 6: remove the protective layer, connect the upper side sealing structure to the swing edges on both sides of the substrate to obtain the micro pump body; connect the second flow layer, the part of the support structure away from the second flow layer, and the first flow layer to the micro pump body through a bonding process.

[0036] The present invention has the following beneficial effects:

[0037] 1. The two actuating units in the present invention are in a cantilever structure that is arranged in parallel and on opposite sides. When different excitation signals are input to the two actuating units, the two actuating units can vibrate asynchronously, thereby generating a reverse airflow with a certain degree of continuity in the piezoelectric micropump, thereby playing a role in regular self-cleaning of the air inlet, and realizing long-term continuous operation of the piezoelectric micropump in a complex environment.

[0038] 2. The actuator unit in the present invention adopts a swinging vibration mode, and the central stress similar to that of a conventional annular actuator structure will not be generated during the swinging pumping process, which helps to extend the service life of the piezoelectric micropump. At the same time, the present invention connects a stretchable polymer between the two swinging edges of the actuator substrate and the side wall of the inner cavity of the support structure, which does not affect the vibration of the actuator and prevents the fluid from passing through the side, but can only pass through the flow gap, further increasing the flow rate and pressure.

[0039] 3. The present invention sets a gradient structure at the air outlet on the flow layer. When the vibration element vibrates toward the air outlet, the air near the step can be more easily compressed, thereby increasing the air viscosity in this area and achieving a more efficient air pumping effect.

[0040] 4. In the present invention, a stepped structure is provided at the air inlet on the flow layer, and Bernoulli's principle is used to generate a vortex at the stepped structure when the vibrating element vibrates toward the air inlet, thereby inhibiting the fluid from flowing back to the outside of the air inlet and reducing backflow.

[0041] 5. The present invention uses micro-nano technology to prepare a heat dissipation pump, which has a smaller size and lower power consumption. Compared with the traditional piezoelectric pump fixed on all sides, the present invention sets a tiny flow gap on the substrate to reduce the impact of residual stress on the piezoelectric device. At the same time, by applying different excitation signals to the vibration elements on the substrate, the functions of forward pumping gas heat dissipation and reverse self-cleaning can be achieved, which is more suitable as a heat dissipation element for electronic devices and has a wide range of application scenarios. In addition, the present invention generates two independent vibration elements on the surface of the substrate. Changing the position of the vibration element on the substrate can balance the performance and power consumption of the device and improve the energy conversion efficiency. And the asynchronous vibration of the two independent vibration elements can pump gas in the opposite direction to achieve self-cleaning of the piezoelectric micropump. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic cross-sectional structure diagram of the first embodiment of the present invention.

[0043] Figure 2 Schematic top view of the actuator in Example 1 of the present invention.

[0044] Figure 3 It is a schematic diagram of the cross-sectional structure of the vibration element at a certain position in the center of the substrate in Example 1 of the present invention.

[0045] Figure 4 This is a comparison chart of normalized performance and power consumption when the center point of the vibration element described in Example 1 of the present invention is at different positions on the substrate.

[0046] Figure 5 Schematic diagram of the working mode of forward pumping in Example 1 of the present invention.

[0047] Figure 6 Schematic diagram of the working mode of reverse self-cleaning in Example 1 of the present invention.

[0048] Figure 7 This is a schematic diagram of the first step of device preparation in Example 2 of the present invention.

[0049] Figure 8 This is a schematic diagram of step 2 of device preparation in Example 2 of the present invention.

[0050] Fig. 9 This is a schematic diagram of step 3 of device preparation in Example 2 of the present invention.

[0051] Fig.10 This is a schematic diagram of step 4 of device preparation in Example 2 of the present invention.

[0052] Fig.11 This is a schematic diagram of step 5 of device preparation in Example 2 of the present invention.

[0053] Fig.12 This is a schematic diagram of step 6 of device preparation in Example 2 of the present invention.

[0054] Fig.13 This is a schematic diagram of step 7 of device preparation in Example 2 of the present invention.

[0055] Fig.14 This is a schematic cross-sectional structure diagram of Example 3 of the present invention.

[0056] Fig.15 This is a schematic diagram of the cross-sectional structure of Example 4 of the present invention.

[0057] Fig.16 This is a schematic cross-sectional structure diagram of Example 5 of the present invention.

[0058] Fig.17 This is a schematic diagram of the cross-sectional structure of Example 6 of the present invention.

[0059] Fig.18 This is a schematic diagram of the cross-sectional structure of Example 7 of the present invention. DETAILED DESCRIPTION

[0060] The present invention will be further described below in conjunction with the accompanying drawings.

[0061] The first embodiment of the present invention is further described below with reference to the accompanying drawings.

[0062] like Figure 1 and Figure 2 As shown, a oscillating oscillator type piezoelectric micro pump includes a first flow layer 10, a hollow support structure 40 with two ends open, and a second flow layer 30 which are stacked in sequence, and an actuator arranged in the support structure 40.

[0063] The actuator includes two actuator units arranged left and right. The opposite sides of the two actuator units are fixedly connected to the opposite side walls of the inner cavity of the support structure 40. A flow gap 300 is provided between the adjacent sides of the two actuator units. The actuator divides the inner cavity of the support structure 40 into an input chamber 100 and an output chamber 200. The input chamber 100 is located between the actuator and the first flow layer 10. The output chamber 200 is located between the actuator and the second flow layer 30. The input chamber 100 and the output chamber 200 are connected through the flow gap 300.

[0064] The actuating unit includes a substrate 20, a side sealing structure 50 and a vibrating element 21. The four edges of the substrate 20 are respectively a fixed edge, a movable edge and two swinging edges. The two swinging edges are one set of opposite edges of the substrate 20; the fixed edge and the movable edge are the other set of opposite edges of the substrate 20. The fixed edges of the two substrates 20 are respectively fixed to a set of opposite side surfaces of the inner cavity of the support structure 40. The two swinging edges of the substrate 20 are close to the corresponding inner side walls of the support structure 40 and a gap is left.

[0065] The two swinging edges of the substrate 20 are both provided with side sealing structures 50. The side sealing structures 50 are in contact with the corresponding inner side walls of the support structure 40, closing the gap between the swinging edge of the substrate 20 and the inner side wall of the support structure 40, realizing the side sealing between the two swinging edges of the substrate 20 and the inner side wall of the support structure 40, ensuring that the actuator can vibrate freely at the axial end, and making the fluid flow only through the flow gap 300 during the operation of the piezoelectric micro pump.

[0066] The vibration elements 21 in the two actuation units are connected to three electrode interfaces, that is, one side of the two vibration elements 21 is commonly grounded, and the other sides are respectively connected to independent power supply control interfaces, so that the two vibration elements 21 can be independently controlled.

[0067] In this embodiment, the side sealing structure 50 is made of elastic sealing material, preferably polymer material, more preferably Parylene C or other xylene polymers. The side sealing structure 50 can block the fluid from passing through the swing edge of the substrate 20 without affecting the vibration of the actuator, so that the fluid can only pass through the flow gap 300, thereby improving the overall pressure and flow output of the device.

[0068] like Figure 1 and Figure 2 As shown, in this embodiment, the support structure 40 plays a supporting role in the overall device, surrounds the device, and its structure is usually square or circular, with a width or diameter not greater than 3000 μm (preferably 2000 μm). The material of the support structure 40 is one or more of stainless steel, silicon, silicon compounds, and germanium compounds.

[0069] like Figure 1 , 2 As shown, since the two actuating units of the actuator in this embodiment are independent of each other and form a flow gap 300, the actuator in this embodiment will not generate residual stress in the center of the vibration process of a conventional annular actuator structure with fixed peripheries; in some embodiments, asynchronous vibration of the two actuating units can be achieved by passing driving signals of different frequencies or of the same frequency but different phases into the vibration elements 21 in the two actuating units.

[0070] In this embodiment, the material of the substrate 20 is silicon; in some other embodiments, the substrate 20 may also be made of metals such as stainless steel, titanium alloy, or one or more of silicon-containing compounds (preferably silicon dioxide) and germanium-containing compounds.

[0071] In this embodiment, the initial width of the flow gap 300 is controlled between 10 μm and 100 μm; when the actuator is in a stationary state, the flow gap 300 with a width of only 10 μm to 100 μm can be approximately considered closed, that is, the fluid cannot pass through the flow gap 300 or only a small amount of fluid can pass through (which can be ignored).

[0072] like Figure 1 , 3 As shown, the flow gap 300 and the two independent substrates 20 are obtained by etching and dividing a complete layer structure in the middle. The two vibration elements 21 can be produced by dividing a whole large piezoelectric material after etching the flow gap 300, or they can be independently formed at two symmetrical positions of the actuator. The vibration element 21 uses piezoelectric materials, including but not limited to lead zirconate titanate, aluminum nitride, scandium-doped aluminum nitride, PMNPT, and has a thickness of 2μm.

[0073] like Figure 3 , 4 As shown, the positions of the two vibration elements 21 on the substrate 20 can be controlled by the process, and the vibration element 21 can be placed at any position on the substrate 20; on the one hand, the vibration element 21 can be placed close to the fixed edge of the substrate 20 to obtain higher performance; this is because the change in the bending moment causes the driving efficiency of the vibration element 21 to change, and the bending moment M can be expressed as: .

[0074] Where F is the driving force, L is the total length of the cantilever beam, and x is the position of the vibration element 21 to the fixed end. When x=0, it means that the vibration element 21 is close to the fixed end, and the bending moment at this time reaches the maximum value, and the driving efficiency is theoretically the highest.

[0075] On the other hand, placing the vibration element 21 away from the fixed edge of the substrate 20 can achieve lower power consumption. The reason is that the rigidity of the substrate 20 near the fixed end is higher, and the mechanical impedance increases. At this time, the vibration element 21 is placed on the side close to the fixed edge, which requires higher energy input to overcome the impedance. At the same time, part of the energy is consumed by the structure of the fixed edge, resulting in increased power consumption. On the contrary, away from the fixed edge, the driving torque can be more easily transferred to the free side, the energy conversion efficiency is higher, and the power consumption is reduced.

[0076] like Figure 4 As shown, in order to balance power consumption and performance, the distance from the center point of the vibration element to the fixed edge of the substrate is 40% to 60% (preferably 60%) of the distance from the fixed edge of the substrate to the active edge. The length of the vibration element is the maximum value of the distance from the fixed edge of the substrate to the active edge, preferably 30% to 50% (preferably 50%). In this embodiment, the distance from the fixed edge of the substrate to the active edge is 600μm to 800μm (preferably 800μm).

[0077] like Figure 3 As shown, an air inlet 11 is provided on a group of opposite sides of the first flow layer 10 away from the flow gap 300; the air inlet 11 can be a long strip structure or a queue air inlet structure formed by sequentially arranging a plurality of through holes. The length direction of the air inlet 11 is parallel to the length direction of the flow gap 300. The width of the air inlet 11 is between 30 μm and 50 μm (preferably 40 μm).

[0078] like Figure 3 As shown, the second flow layer 30 is provided with an air outlet 31 aligned with the flow gap 300 at the center. The air outlet 31 can be a long strip structure or a queue air intake structure formed by a plurality of through holes arranged in sequence. The length direction of the air outlet 31 is parallel to the length direction of the flow gap 300. The width of the air outlet 31 is controlled between 100 μm and 120 μm (preferably 110 μm).

[0079] In the initial state, the height of the input chamber 100 is greater than the height of the output chamber 200 ; in this embodiment, the height of the input chamber 100 is greater than or equal to 300 μm; and the height of the output chamber 200 is less than or equal to 120 μm.

[0080] The inner side of the first flow layer 10 (i.e., the side close to the actuator) is provided with an air intake concave structure 12 connected to the air intake port 11 on both side edges. The air intake concave structure 12 forms an air intake gradient flow channel structure with a large inner side and a small outer side at the air intake port 11. Since the height of the input chamber 100 is greater than or equal to 300 μm and has sufficient height space, when the actuator vibrates toward the first flow layer 10, the fluid entering the input chamber 100 generates a vortex at the air intake gradient flow channel structure with a large inner side and a small outer side due to the Bernoulli principle, thereby inhibiting the fluid from flowing back to the outside of the air intake port.

[0081] The middle of the inner side surface (i.e., the side surface close to the actuator) of the second flow layer 30 is provided with an outlet concave structure 32 of the outlet 31. The width of the outlet concave structure 32 is greater than the width of the outlet 31, so that an outlet gradient flow channel structure with a larger inner side and a smaller outer side is formed at the outlet 31; since the height of the output chamber 200 is less than or equal to 120 μm, the flow gap 300 is closer to the outlet 31 during vibration, and the fluid near the outlet gradient flow channel structure will be compressed sharply, causing the temperature of the fluid to rise, thereby helping to increase the flow rate, and improving the pumping efficiency without increasing the aperture of the flow hole.

[0082] In this embodiment, the air inlet concave structure 12 and the air outlet concave structure 32 are both rectangular grooves, so that the air inlet 11 and the air outlet 31 both form a stepped gradient flow channel structure.

[0083] In this embodiment, the width of the air inlet concave structure 12 and the air outlet concave structure 32 using rectangular grooves are both 600 μm to 800 μm, and the depth is less than 100 μm.

[0084] In some other embodiments, the actuator may include only one actuating unit; the fixed edge of the substrate 20 of the actuating unit is fixed to the side of the inner cavity of the support structure; and a flow gap 300 is formed between the movable edge of the actuator and the other opposite side of the inner cavity of the support structure.

[0085] The working principle of the oscillating vibrator piezoelectric micropump provided in this embodiment is as follows:

[0086] The two actuating units in the actuator can be driven by the excitation signal to generate vibrations toward the first flow layer 10 or the second flow layer 30. By applying the same or different excitation signals to the vibration elements 21 in the two actuating units, the actuator generates two different vibration modes to achieve two different functions of forward pumping and reverse self-cleaning.

[0087] like Figure 5As shown, the forward pumping process is: applying excitation signals of the same frequency and phase to the two vibration elements 21, the two substrates 20 are driven by the vibration elements 21 to vibrate in the same direction (vibrate in the same direction), so that the volume inside the micropump changes, and a pressure difference is generated inside and outside. When the two substrates 20 swing towards the direction close to the second flow layer 30 at the same time, the volume of the input chamber 100 increases, while the volume of the output chamber 200 decreases. The gas enters the pump body through the air inlet 11 on the first flow layer 10, and there is a tendency to flow in the direction close to the flow gap 300. At the same time, the distance between the substrate 20 and the air outlet concave structure 32 gradually decreases, and the gas near the outlet 31 in the output chamber 200 is sharply compressed, and the gas viscosity increases, so that the gas inside the output chamber 200 is mainly pumped out from the outlet 31 and does not flow back to the input chamber 100 through the flow gap 300;

[0088] When the substrate 20 swings toward the first flow layer 10 at the same time, the volume of the input chamber 100 decreases, while the volume of the output chamber 200 increases. Since the height of the input chamber 100 is higher than that of the output chamber 200, when the actuator vibrates toward the first flow layer 10, the stepped structure with a larger inside and a smaller outside will generate a vortex at the stepped structure due to the Bernoulli principle, thereby inhibiting the fluid from flowing back to the outside of the air inlet, and more gas flows from the input chamber 100 through the flow gap 300 into the output chamber 200, forming a circulation.

[0089] like Figure 6 As shown, the reverse self-cleaning process is: two different excitation signals are applied to the two vibration elements 21 respectively; in this embodiment, there is a certain difference in the frequency of the two different excitation signals, which is set to 50Hz in this embodiment, so that the two actuator units vibrate asynchronously, and the width of the flow gap 300 between the two substrates 20 changes greatly; at this time, the gas inside the piezoelectric micropump will flow in the reverse direction different from the forward pump gas, so that the airflow enters from the outlet 31, passes through the output chamber 200, the flow gap 300 and the input chamber 100, and is output from the air inlet 11. In order to achieve that the first substrate 20 vibrates toward the first ventilation layer 10, while the second substrate 20 vibrates toward the second ventilation layer 30, and vice versa. When the actuator vibrates in an opposite direction, the gas flows from the outlet 31 of the second flow layer 30 into the output chamber 200, then flows into the input chamber 100 through the flow gap 300, and finally is discharged from the air inlet 11.

[0090] In this embodiment, reverse self-cleaning can blow away the dust blocked at the air inlet 11 during the forward pumping process, thereby clearing the dust and restoring the flow rate drop of the piezoelectric micropump caused by the blockage of the air inlet 11, so that the piezoelectric micropump can continue to blow air to dissipate heat to the external heating structure efficiently.

[0091] Example 2

[0092] A method for preparing a piezoelectric micropump is used to prepare the oscillating oscillator type piezoelectric micropump provided in Example 1.

[0093] The piezoelectric micropump preparation method comprises the following steps:

[0094] S1. The device embryo is obtained by micro-nano processing; the device embryo includes a substrate BA, an insulating layer IL1 and a structural layer SL stacked in sequence. The material of the substrate BA is usually one of silicon, silicon compounds, germanium, gallium, and stainless steel; the material of the insulating layer IL1 is an oxide, usually silicon dioxide, which acts as an electrical insulating material to prevent the direct flow of current between the substrate BA and the structural layer SL, ensuring that the electrical signal can be correctly transmitted to the actuator. The material of the structural layer SL is usually one of silicon, silicon compounds, germanium, gallium, and stainless steel. Figure 7 As shown, a bottom electrode E1 is formed on the structural layer, and its material is usually metal or other conductive materials.

[0095] S2. Figure 8 As shown, a piezoelectric layer PL is grown on the structural layer SL, and the methods include but are not limited to bonding piezoelectric sheets, magnetron sputtering, PLD (pulsed laser deposition), CVD (chemical vapor deposition), gel method, etc. At the same time, the piezoelectric layer PL is patterned to form a vibration element 21 with a specific pattern, or it can be non-patterned and directly covered on the surface of the structural layer SL. The material is usually a piezoelectric film such as lead zirconate titanate, aluminum nitride, and doped aluminum nitride;

[0096] S3. Fig. 9 As shown, a layer of photoresist is deposited on the surface of the piezoelectric layer PL and patterned, and then the top electrode E2 is formed on the two vibration elements 21 of the piezoelectric layer PL by electron beam evaporation and lift-off;

[0097] In other embodiments, the vibration element 21 may also be formed in a non-patterning manner, specifically: the piezoelectric layer PL is not grown, but the formed vibration element 21 is directly covered on the structural layer SL. Fig.10 As shown, deep reactive ion etching is used to perform I-shaped etching on the middle and both side edges of the structural layer SL to form a flow gap 300 and an indented structure on both sides of the structural layer SL; the flow gap 300 separates the structural layer SL into two substrates 20; the indented structure forms the swinging edge of the substrate 20.

[0098] S5. Fig.11 As shown, a protective layer PRL is deposited on the front side of the device obtained in step S5. The material of the protective layer PRL is usually polyimide, and its function is to protect the internal structure from being etched;

[0099] S6. Fig.12As shown, the back of the substrate BA is etched by etching to form an output chamber; at this time, the swing edge of the substrate 20 formed by the structure layer SL is suspended relative to the substrate BA.

[0100] S7. Fig.13 As shown, the protective layer PRL on the front side of the device obtained in step S7 is removed to complete the processing of the micro pump body.

[0101] S8. The side sealing structure 50 is bonded to the swinging edges on both sides of the substrate 20; then, another silicon wafer is taken and a first flow layer and an input chamber 100 are formed by etching; another silicon wafer is taken and a second flow layer is formed by etching. The two processed silicon wafers are respectively connected to the two sides of the micro pump body by silicon-silicon bonding process to form a complete piezoelectric micro pump.

[0102] Example 3

[0103] A swing oscillator piezoelectric micro pump, the difference between this embodiment and embodiment 1 is that the structure of the air inlet gradient flow channel and the structure of the air outlet gradient flow channel are different.

[0104] In this embodiment, the air inlet concave structure 12 and the air outlet concave structure 32 are both double-layer step structures; the bottom surface of the double-layer step structure is two-layer stepped, so that the air inlet 11 and the air outlet 31 both form a stepped gradient flow channel structure.

[0105] like Fig.14 As shown, the inlet concave structure 12 and the outlet concave structure 32 provided in this embodiment can provide a smoother airflow transition, reduce the turbulence and eddy current of the airflow when entering and leaving the piezoelectric micropump, and thus reduce the fluid resistance. Compared with the single-layer right-angle step structure provided in embodiment 1, the double-layer step structure provided in this embodiment can reduce the pressure loss and further reduce the resistance encountered by the fluid when passing through.

[0106] Example 4

[0107] A swing oscillator piezoelectric micro pump, the difference between this embodiment and embodiment 1 is that the structure of the air inlet gradient flow channel and the structure of the air outlet gradient flow channel are different.

[0108] In this embodiment, the air inlet concave structure 12 and the air outlet concave structure 32 are both bevel groove structures; the bottom surface of the bevel groove structure is an inclined plane, so that the air inlet 11 and the air outlet 31 both form a gradient flow channel structure in the shape of an oblique funnel.

[0109] like Fig.15As shown, the inlet concave structure 12 and the outlet concave structure 32 provided in this embodiment can provide a smoother airflow transition, reduce the turbulence and eddy current of the airflow when entering and leaving the piezoelectric micropump, and thus reduce the fluid resistance. Compared with the right-angle step structure provided in embodiment 1, the oblique funnel-shaped structure provided in this embodiment can reduce the pressure loss and further reduce the resistance encountered by the fluid when passing through.

[0110] Example 5

[0111] A swing oscillator piezoelectric micro pump, the difference between this embodiment and embodiment 1 is that the structure of the air inlet gradient flow channel and the structure of the air outlet gradient flow channel are different.

[0112] In this embodiment, the air inlet concave structure 12 and the air outlet concave structure 32 are both arc-shaped groove structures, and the bottom surface of the arc-shaped groove structure is an inwardly concave arc surface, so that the air inlet 11 and the air outlet 31 both form an arc-shaped funnel-shaped gradient flow channel structure.

[0113] like Fig.16 As shown, the inlet concave structure 12 and the outlet concave structure 32 provided in this embodiment can provide a smoother airflow transition, reduce the turbulence and eddy current of the airflow when entering and leaving the piezoelectric micropump, and thus reduce the fluid resistance. Compared with the right-angle step structure provided in embodiment 1, the arc-shaped funnel-shaped structure provided in this embodiment can reduce the pressure loss and further reduce the resistance encountered by the fluid when passing through.

[0114] Example 6

[0115] A swing oscillator type piezoelectric micro pump, the difference between this embodiment and embodiment 1 is that the shape of the second flow layer 30 is different.

[0116] In this embodiment, the inner side surface of the second flow layer 30 (i.e., the side surface close to the actuator) is in an inwardly concave arc shape on both sides of the air outlet concave structure 32. In the direction from the air outlet concave structure 32 to the edge of the second flow layer 30, the inner side surface of the second flow layer 30 gradually approaches the actuator.

[0117] like Fig.17 As shown, the present embodiment optimizes the design of the second flow layer 30 to improve the pumping performance of the device. By designing the second flow layer 30 as a curved surface, the gas flow can be more effectively guided, the flow resistance can be reduced, and the pressure distribution can be optimized, thereby improving the performance of the entire heat dissipation pump. The curvature of the curved surfaces on both sides of the second flow layer 30 changes continuously, so that the height of the output chamber 200 gradually decreases from the support structure 40 to the air outlet 31, so that when the actuator vibrates toward the second flow layer 30, the space of the output chamber 200 away from the air outlet 31 is sharply compressed, so that the pressure vibration amplitude away from the air outlet 31 is reduced, which helps to improve the overall efficiency of the device.

[0118] Example 7

[0119] A swing oscillator type piezoelectric micro pump, the difference between this embodiment and embodiment 1 is that the shape of the second flow layer 30 is different.

[0120] In this embodiment, the inner side surface of the second flow layer 30 (i.e., the side surface close to the actuator) is in an inclined plane shape on both sides of the air outlet concave structure 32. In the direction from the air outlet concave structure 32 to the edge of the second flow layer 30, the inner side surface of the second flow layer 30 gradually approaches the actuator.

[0121] like Fig.18 As shown, the present embodiment optimizes the design of the second flow layer 30 to improve the pumping performance of the device. By designing the second flow layer 30 as an inclined plane, the gas flow can be more effectively guided, the flow resistance can be reduced, and the pressure distribution can be optimized, thereby improving the performance of the entire heat dissipation pump. In the present embodiment, the height of the output chamber 200 is gradually reduced from the support structure 40 to the air outlet 31, so that when the actuator vibrates toward the second flow layer 30, the space of the output chamber 200 away from the air outlet 31 is sharply compressed, so that the pressure vibration amplitude away from the air outlet 31 is helped to improve the overall efficiency of the device.

[0122] Example 8

[0123] A heat dissipation system uses the piezoelectric micropump provided in any one of Embodiments 1 and Embodiments 3-7 as a heat dissipation pump gas element; at this time, the second flow layer 30 in the piezoelectric micropump is spaced apart from the actuator and is opposite to an external heating structure (not shown in the figure), forming a heat dissipation flow channel, which can effectively dissipate heat from the heating structure. High-speed gas continuously flows to the external heating structure (not shown in the present invention) opposite to the second flow layer 30 through the gas outlet 31, achieving the effect of dissipating heat from the external heating structure.

Claims

1. An oscillating oscillator type piezoelectric micropump, comprising a support structure (40), a first flow layer (10) and a second flow layer (30) arranged at both ends of the support structure (40), and an actuator arranged in the support structure (40); an input chamber (100) is formed between the actuator and the first flow layer (10); an output chamber (200) is formed between the actuator and the second flow layer (30); characterized in that: The actuator comprises two actuating units arranged in parallel; the actuating units comprise a substrate (20) and a vibrating element (21); the vibrating element (21) is fixed on the substrate (20); the four edges of the substrate (20) are respectively a fixed edge, a movable edge and two swinging edges; The first flow-through layer (10) has two edges parallel to the flow-through slits (300) each provided with an air inlet (11); the second flow-through layer (30) has an air outlet (31) aligned with the flow-through slits (300); The fixed edges of the substrates (20) of the two actuating units are respectively fixed to a group of opposite side surfaces of the inner cavity of the support structure (40); a flow gap (300) is formed between the movable edges of the substrates (20) of the two actuating units; the initial width of the flow gap (300) is 1 μm to 100 μm; the height of the input chamber (100) is greater than the height of the output chamber (200); A side sealing structure (50) is provided between the swing edge of the base plate (20) and the corresponding inner side wall on the support structure (40); the side sealing structure (50) is fixed on the swing edge of the base plate (20) and is in contact with the corresponding inner side wall on the support structure (40).

2. The oscillating vibrator piezoelectric micropump according to claim 1, characterized in that: The side of the second flow layer (30) close to the actuator is in the shape of an inclined plane or a curved surface that gradually approaches the actuator from the outlet gradient flow channel structure to the edges on both sides.

3. The oscillating vibrator piezoelectric micro pump according to claim 1, characterized in that: One side of the vibration elements (21) in the two actuation units is commonly grounded, and the other side is respectively connected to an independent power supply control interface.

4. The oscillating vibrator piezoelectric micropump according to claim 1, characterized in that: An air intake concave structure (12) connected to the air intake port (11) is provided on the side of the first flow layer (10) close to the actuator; the air intake concave structure (12) and the air intake port (11) together form an air intake gradient flow channel structure that is larger inside and smaller outside; an air outlet concave structure (32) connected to the air outlet port (31) is provided on the side of the second flow layer (30) close to the actuator; the air outlet concave structure (32) and the air outlet port (31) together form an air outlet gradient flow channel structure that is larger inside and smaller outside.

5. The oscillating vibrator piezoelectric micro pump according to claim 4, characterized in that: The air intake gradient flow channel structure adopts any one of the following structures: Structure 1: One or more stepped planes are provided on the air intake concave structure (12), so that the air intake gradient flow channel structure is in a stepped shape; Structure 2: The air intake concave structure (12) is in the shape of an oblique groove, so that the air intake gradient flow channel structure is in the shape of an oblique funnel; Structure 3: The air intake concave structure (12) is in the shape of an arc-shaped groove, so that the air intake gradient flow channel structure is in the shape of an arc-shaped funnel; The outlet gradient flow channel structure adopts any one of the following structures: Structure 1: One or more stepped planes are provided on the gas outlet concave structure (32), so that the gas outlet gradient flow channel structure is in a stepped shape; Structure 2: The gas outlet concave structure (32) is in the shape of an oblique groove, so that the gas outlet gradient flow channel structure is in the shape of an oblique funnel; Structure three: the gas outlet concave structure (32) is in the shape of an arc-shaped groove, so that the gas outlet gradient flow channel structure is in the shape of an arc-shaped funnel.

6. The oscillating vibrator piezoelectric micro pump according to claim 1, characterized in that: The distance from the center point of the vibration element (21) to the fixed edge of the substrate (20) is 40% to 60% of the distance from the fixed edge to the movable edge of the substrate (20); and the length of the vibration element is 30% to 50% of the distance from the fixed edge to the movable edge of the substrate.

7. A pump air driving method, characterized in that: Using a oscillating vibrator piezoelectric micro pump as claimed in claim 1; characterized in that: the pumping air driving method includes a forward pumping air method and a reverse self-cleaning method; The forward pumping method comprises: applying an excitation signal of the same frequency and the same phase to two vibration elements (21), so that the two substrates (20) are driven by the vibration elements (21) to vibrate synchronously in the same direction, driving the airflow to enter from the air inlet (11), pass through the input chamber (100), the flow gap (300) and the output chamber (200), and then be output from the air outlet (31); The reverse self-cleaning method comprises: applying different excitation signals to the two vibration elements (21), the two substrates (20) vibrate asynchronously under the drive of the vibration elements (21), and the gas in the piezoelectric micropump flows in the reverse direction during part or all of the operation time, with the gas entering from the gas outlet (31) and being discharged from the gas inlet (11).

8. A method for preparing a piezoelectric micropump, for preparing the oscillating vibrator type piezoelectric micropump as claimed in claim 1; characterized in that: The piezoelectric micropump preparation method comprises the following steps: Step 1: Processing to obtain a device embryonic body formed by sequentially stacking a substrate, an insulating layer and a structural layer; Step 2: forming a vibration element (21) on the structural layer; Step 3: forming top electrodes on the two vibration elements (21); Step 4: etching the middle and both side edges of the structural layer so that an I-shaped gap is formed in the middle and both sides of the structural layer; the I-shaped gap divides the structural layer into two independent substrates (20); Step 5: a protective layer is provided on the front side of the device obtained in step 5, and the back side of the substrate is etched to form an output chamber; Step six: remove the protective layer, connect the upper side sealing structure (50) to the swing edges on both sides of the substrate (20), and obtain the micro pump body; connect the second flow layer (30), the part of the support structure (40) away from the second flow layer (30), and the first flow layer (10) to the micro pump body through a bonding process.

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