Unidirectional flow driver and manufacturing method thereof

Abstract

The invention relates to the technical field of control devices, and provides a unidirectional flow driver and a manufacturing method thereof, and the unidirectional flow driver comprises a housing and a control unit. The shell is provided with a first opening part and a second opening part, the control unit comprises a first base and a cantilever type driver, a cantilever gap is formed at the free end, and any two of the first opening part, the second opening part and the cantilever gap are at least partially overlapped in the vibration direction of the cantilever type driver; the following three conditions are set: condition 1, the volume of the first conduction space is different from that of the second conduction space; the condition 2 is that the caliber of the first opening part is equal to the caliber of the second opening part; condition 3 is that the aperture of the cantilever gap is smaller than the apertures of the first opening and the second opening. The one-way flow driver satisfies the condition 1, and satisfies at least one of the condition 2 and the condition 3, thereby realizing a high-flow one-way flow function and reliability.

Description

Technical Field

[0001] This invention relates to the field of control device technology, and in particular to a unidirectional flow driver and its manufacturing method. Background Technology

[0002] Unidirectional flow actuators are core components in fluid control systems. Their function is to control the fluid to flow in a preset unidirectional direction, thereby ensuring the stability of system operation, the safety of components, and the accuracy of fluid delivery. They can be applied to various occasions such as pumps, fans, and material transport.

[0003] In related technologies, a unidirectional flow actuator includes a control unit and a package structure. The control unit is located inside the package structure and separates the package structure to form two chambers. The package structure has two flow channels running through it, connecting the outside to the two chambers. The package structure also has a through hole connecting the two chambers. In order to achieve unidirectional flow, the two flow channels are staggered to construct an asymmetrical unidirectional flow actuator. At this time, the fluid enters from one flow channel, flows out from the other flow channel after passing through the through hole. Because the two flow channels are staggered in the direction of fluid flow, the fluid flow channel is longer, which increases the flow resistance at the flow channel, resulting in a small fluid flow rate and low unidirectional flow efficiency.

[0004] Therefore, it is necessary to provide a new unidirectional flow driver to solve the above problems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a unidirectional flow actuator with high efficiency and high reliability in unidirectional fluid flow.

[0006] To solve the above-mentioned technical problems, in a first aspect, embodiments of the present invention provide a unidirectional flow driver, the unidirectional flow driver including a housing having a cavity and at least one control unit located within the housing; The control unit divides the cavity into a first conductive space and a second conductive space; the housing is provided with a first opening and a second opening that pass through it, the first opening communicating with the first conductive space and the second opening communicating with the second conductive space; The control unit includes a first base fixed inside the housing and a cantilever actuator fixed to the first base. The cantilever actuator divides the cavity into a first conductive space and a second conductive space. The first base is disposed within the first conductive space. One end of the cantilever actuator is fixed to the first base, and the other end of the cantilever actuator forms a cantilever gap. The cantilever gap connects the first conductive space and the second conductive space, allowing fluid to flow in from one of the first opening and the second opening and out from the other of the first opening and the second opening. Any two of the first opening, the second opening, and the cantilever gap overlap at least partially in the vibration direction of the cantilever actuator; Among them, the following three conditions are set: Condition 1 is that the volume of the first conductive space and the volume of the second conductive space are different; Condition 2 is that the diameter of the first opening is equal to the diameter of the second opening; Condition 3 is that the diameter of the cantilever gap is smaller than the diameters of the first opening and the second opening. The unidirectional flow driver satisfies condition 1, and at least one of conditions 2 and 3.

[0007] Preferably, the diameter of the cantilever gap is greater than 5 micrometers.

[0008] Preferably, when the volume of the first conductive space and the volume of the second conductive space are different, and the diameter of the first opening is equal to the diameter of the second opening, the fluid flows in from the opening corresponding to the larger conductive space in the first and second conductive spaces, and flows out from the opening corresponding to the smaller conductive space in the first and second conductive spaces.

[0009] Preferably, the housing includes a first connecting plate in an annular shape, and a second connecting plate and a third connecting plate fixed to opposite ends of the first connecting plate; the first connecting plate, the second connecting plate, and the third connecting plate are connected and together form the cavity; the first opening is disposed through the second connecting plate, and the second opening is disposed through the third connecting plate; the control unit includes a first base and a cantilevered actuator, the first base is abutted and fixed to one side of the first connecting plate, and the cantilevered actuator is spaced apart from the other side of the side plate to form the cantilever gap.

[0010] Preferably, the first connecting plate further includes an extension portion extending along the extension direction of the cantilever driver, the extension portion being located within the second conductive space, and the cantilever driver being clamped and fixed between the extension portion and the first base.

[0011] Preferably, the unidirectional flow driver further includes a third opening formed through the first connecting plate, the third opening communicating with the second conductive space, and the third opening and the second opening being spaced apart from each other.

[0012] Preferably, the unidirectional flow actuator further includes a second base located in the second conductive space, the second base and the first base being disposed opposite to each other in the vibration direction of the cantilever actuator, and the cantilever actuator being clamped and fixed between the first base and the second base.

[0013] Preferably, the housing includes a first connecting plate in an annular shape, and a second connecting plate and a third connecting plate fixed to opposite ends of the first connecting plate; the first connecting plate, the second connecting plate, and the third connecting plate are connected and together form the cavity; the first opening passes through the second connecting plate, and the second opening passes through the third connecting plate; the control unit includes two first bases and two cantilever actuators, the two first bases are respectively abutted and fixed to opposite sides of the side plate, one end of each of the two cantilever actuators is respectively fixed to the two first bases, and the other ends of the two cantilever actuators are opposite to each other and spaced apart to form the cantilever gap.

[0014] Preferably, the unidirectional flow driver further includes a third opening and a fourth opening formed through the first connecting plate, both of which are connected to the second conductive space, and the centers of the third opening and the fourth opening coincide in the extension direction of the cantilever driver.

[0015] Preferably, the operating frequency of the control unit is greater than 20KHz.

[0016] Preferably, the control unit includes at least two arranged in a linear array within the housing, and the cantilevered actuators of all the control units together divide the cavity into a first conductive space and a second conductive space; the number of the first opening and the number of the second opening are the same as the number of the control units, and each control unit is matched with one first opening and one second opening.

[0017] Secondly, embodiments of the present invention also provide a method for manufacturing a unidirectional flow actuator as described above, characterized in that the manufacturing method is a machining method, the machining method comprising the following steps: A substrate is provided, on which a cantilever gap and a cantilever beam are processed, and a piezoelectric ceramic sheet is attached to the cantilever beam to obtain a cantilever actuator; A top frame with a first through hole and a bottom frame with a second through hole are provided, and the top frame and the bottom frame are respectively attached to opposite sides of the substrate; A top cover and a bottom cover are provided. The top cover is attached to the side of the upper frame away from the lower frame, and the bottom cover is attached to the side of the lower frame away from the upper frame. The bottom cover, the lower frame and the substrate together form a first conductive space, and the top cover, the upper frame and the substrate together form a second conductive space. The lower frame is set as a first base. A first opening and a second opening are respectively pre-set on the bottom cover and the top cover. The first opening, the second opening and the cantilever gap are interconnected, and any two of the first opening, the second opening and the cantilever gap at least partially overlap in the vibration direction of the cantilever actuator.

[0018] Thirdly, embodiments of the present invention also provide a method for manufacturing a unidirectional flow actuator as described above, wherein the manufacturing method is a MEMS manufacturing process, and the MEMS manufacturing process includes the following steps: A silicon-on-insulator (SiI) wafer is provided, comprising, from bottom to top, a substrate layer, a buried oxide layer, and a device layer, wherein the substrate layer and the device layer are composed of monocrystalline silicon, the buried oxide layer is composed of silicon dioxide, and the thickness of the device layer is less than the thickness of the substrate layer. The cantilever gap and cantilever beam are fabricated on the device layer by photolithography and etching processes; a first metal electrode, a piezoelectric thin film and a second metal electrode are sequentially deposited on the cantilever beam to obtain the cantilever actuator; The intermediate region between the substrate layer and the buried oxide layer is removed by photolithography and etching processes to form the first conductive space. The outer regions of the substrate layer and the buried oxide layer form the first base, thus obtaining a MEMS chip. A base plate made of a printed circuit board is provided, and a first opening is formed through the base plate; The substrate layer of the MEMS chip is fixed to the base plate; A housing with a cavity is provided, and a second opening is formed through the housing, and the housing is covered and fixed on the base plate; The cantilever actuator divides the cavity into a first conductive space and a second conductive space. The first conductive space is connected to the first opening, and the second conductive space is connected to the second opening. Any two of the first opening, the second opening, and the cantilever gap at least partially overlap in the vibration direction of the cantilever actuator.

[0019] Preferably, the piezoelectric film is made of any one of the piezoelectric materials selected from PZT, AlN, AlScN, KNN, and ZnO.

[0020] Compared with related technologies, this invention features a structure in which any two of the first opening, second opening, and cantilever gap overlap at least partially along the vibration direction of the cantilever actuator, forming a straight-through structure. This reduces fluid flow resistance and path deflection, improves unidirectional flow efficiency, and achieves this by setting the following three conditions: Condition 1 is that the volumes of the first and second conductive spaces are different; Condition 2 is that the diameters of the first and second openings are equal; and Condition 3 is that the diameter of the cantilever gap is smaller than the diameters of the first and second openings. The unidirectional flow actuator satisfies Condition 1 and at least one of Conditions 2 and 3. By constructing two conductive spaces with different volumes, the pressure distribution in the first and second conductive spaces is different, and the flow resistance of the two openings is different, thus achieving unidirectional fluid flow. This invention has a simple structure that is easy to manufacture, avoids the use of various active or passive valves, has a short flow path, and utilizes the dimensional relationships of the structural components to achieve high-flow-rate unidirectional flow and significantly improves long-term operational reliability. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 A schematic diagram of the unidirectional flow condition 1 of the unidirectional flow driver provided in this embodiment of the invention. Figure 1 ; Figure 2 A schematic diagram of the unidirectional flow condition 1 of the unidirectional flow driver provided in this embodiment of the invention. Figure 2 ; Figure 3 A schematic diagram of the unidirectional flow condition 1 of the unidirectional flow driver provided in this embodiment of the invention. Figure 3 ; Figure 4 A schematic diagram of the unidirectional flow condition 1 of the unidirectional flow driver provided in this embodiment of the invention. Figure 4 ; Figure 5 A graph showing the fluid rate versus time under unidirectional flow condition 1 for a unidirectional flow actuator provided in an embodiment of the present invention; Figure 6 A graph showing the cumulative flow rate and time for unidirectional flow condition 1 of the unidirectional flow driver provided in this embodiment of the invention; Figure 7 for Figure 1 This is a schematic diagram of the structure of the second base of the unidirectional flow driver provided in an embodiment of the present invention; Figure 8 for Figure 1 A schematic diagram of the structure of the extension of the unidirectional flow driver provided in an embodiment of the present invention; Figure 9 A schematic diagram of the third opening of a unidirectional flow driver provided in an embodiment of the present invention; Figure 10 A schematic diagram of the fourth opening of a unidirectional flow driver provided in an embodiment of the present invention; Figure 11 A schematic diagram of an array of multiple control units for a unidirectional flow driver provided in an embodiment of the present invention; Figure 12 A schematic diagram illustrating the application of a unidirectional flow driver in a heat dissipation scenario according to an embodiment of the present invention; Figure 13 A schematic diagram of a unidirectional flow actuator structure obtained by the MEMS manufacturing process provided in an embodiment of the present invention; Figure 14 for Figure 13 A magnified view of part A; Figure 15 A schematic diagram of the structure of the unidirectional flow actuator obtained by the machining method provided in the embodiment of the present invention; Figure 16 for Figure 15 Exploded three-dimensional view.

[0022] In the figure, 100 is a unidirectional flow actuator, 1 is a housing, 11 is a second connecting plate, 12 is a first connecting plate, 121 is an extension, 13 is a third connecting plate, 14 is a cavity, 141 is a first conductive space, 142 is a second conductive space, 15 is a first opening, 16 is a second opening, 17 is a third opening, 18 is a fourth opening, 2 is a control unit, 21 is a first base, 22 is a cantilever actuator, 23 is a second base, 24 is a cantilever gap, 25 is a second metal electrode, 26 is a first metal electrode, 27 is a piezoelectric thin film, 28 is a substrate layer, 29 is a buried oxide layer, 30 is a device layer, 200 is a heating object, 31 is a substrate, 311 is a cantilever beam, 32 is a piezoelectric ceramic sheet, 4 is an upper frame, 41 is a first through hole, 5 is a lower frame, 51 is a second through hole, 6 is a top cover, and 7 is a bottom cover. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. 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.

[0024] Example 1 Please see Figures 1-12 As shown, an embodiment of the present invention provides a unidirectional flow driver 100, which includes a housing 1 having a cavity 14 and at least one control unit 2 located within the housing 1. The housing 1 is used to encapsulate and protect the control unit 2.

[0025] Please see Figure 1 The control unit 2 divides the cavity 14 into a first conductive space 141 and a second conductive space 142; the housing 1 is provided with a first opening 15 and a second opening 16 that pass through it, the first opening 15 communicating with the first conductive space 141 and the second opening 16 communicating with the second conductive space 142.

[0026] The control unit 2 includes a first base 21 fixed inside the housing 1 and a cantilevered actuator 22 fixed to the first base 21. The cantilevered actuator 22 divides the cavity 14 into a first conductive space 141 and a second conductive space 142. The first base 21 is disposed inside the first conductive space 141. The first base 21 may be an independent component fixed to the housing 1, or it may be an extension extending from the housing and serving as part of the housing.

[0027] The cantilever actuator 22 includes a free end and a fixed end. The fixed end is fixed to the first base 21. A cantilever gap 24 is formed at the free end, connecting the first conductive space 141 and the second conductive space 142, allowing fluid to flow in from one of the first opening 15 and the second opening 16 and out from the other. By fixing the fixed end of the cantilever actuator 22 to the first base 21, the free end can vibrate up and down along the thickness direction of the cantilever actuator 22 under the action of a drive signal. (See also...) Figure 1 The cantilever actuator 22 extends along the X-axis (horizontal direction) and its thickness is along the Y-axis (vertical direction). The cantilever actuator 22 can be driven by piezoelectric, electrostatic, electromagnetic, or thermoelectric methods.

[0028] Furthermore, any two of the first opening 15, the second opening 16, and the cantilever gap 24 at least partially overlap in the vibration direction of the cantilever actuator 22. Optionally, the vibration direction of the cantilever actuator 22 is the thickness direction of its free end. This overlapping arrangement enhances fluid exchange, allowing fluid flowing from the first opening 15 into the first conductive space 141 to pass more smoothly through the cantilever gap 24 into the second conductive space 142, or allowing fluid flowing from the second opening 16 into the second conductive space 142 to pass more efficiently through the cantilever gap 24 into the first conductive space 141. This overlapping design reduces fluid flow resistance and path deflection, making fluid exchange between the two conductive spaces more direct and efficient. Simultaneously, it helps maintain the stability of fluid flow throughout the housing 1. If the openings do not overlap, the fluid flow path is longer, potentially leading to localized eddies or impaired flow within the conductive spaces. Overlapping openings allow the fluid to form a more regular and shorter flow path within the conductive space, thus ensuring flow stability and facilitating accurate detection or control of fluid-related parameters by the control unit 2. Furthermore, it allows for optimization of the internal layout of the housing 1 while maintaining fluid flow performance, thereby reducing the overall volume of the housing 1.

[0029] Furthermore, the centers of the first opening 15, the second opening 16, and the cantilever gap 24 coincide in the vibration direction of the cantilever actuator 22, which can further improve the efficiency of unidirectional flow.

[0030] Among them, the following three conditions are set: Condition 1 is that the volume of the first conductive space 141 and the volume of the second conductive space 142 are different.

[0031] Condition 2 is that the diameter of the first opening 15 and the diameter of the second opening 16 are equal.

[0032] Condition 3 is that the diameter of the cantilever gap 24 is smaller than the diameter of the first opening 15 and the second opening 16.

[0033] Specifically, in the above unidirectional flow conditions, the unidirectional flow driver 100 needs to satisfy condition 1, and at least one of unidirectional flow conditions 2 and 3 in order to achieve the unidirectional flow control effect.

[0034] Specifically, the volume of the first conductive space 141 is defined as V1, the volume of the second conductive space 142 is defined as V2, the diameter of the first opening 15 is defined as L1, the diameter of the cantilever gap 24 is defined as L2, and the diameter of the second opening 16 is defined as L3.

[0035] In this embodiment, when the volume of the first conduction space 141 is different from the volume of the second conduction space 142, and the diameter of the first opening 15 is equal to the diameter of the second opening 16; the fluid flows in from the opening corresponding to the conduction space with a larger volume between the first conduction space 141 and the second conduction space 142, and flows out from the opening corresponding to the conduction space with a smaller volume between the first conduction space 141 and the second conduction space 142.

[0036] As Figure 2 shown, in the unidirectional flow driver 100, V1 > V2, L1 = L3, and L2 < min(L1, L3). While satisfying condition 1, it also satisfies condition 2 and condition 3, enabling the unidirectional flow function, and the flow direction of the unidirectional flow is from the first opening 15 corresponding to the first conduction space 141 with a larger volume flowing in and flowing out from the second opening 16.

[0037] As Figure 3 shown, in the unidirectional flow driver 100, V1 < V2, L2 < L3 < L1. While satisfying condition 1, it satisfies condition 3. Due to the different volumes and diameters, an asymmetric structure is constructed, the partial pressures of the first conduction space 141 and the second conduction space 142 are different, and the flow resistances of the two openings are different, and the unidirectional flow function can also be achieved.

[0038] As Figure 4 shown, in the unidirectional flow driver 100, V1 < V2, L2 > L3, L1 = L3. While satisfying condition 1, it satisfies condition 2. Due to the different volumes, an asymmetric structure is constructed, the partial pressures of the first conduction space 141 and the second conduction space 142 are different, and the flow resistances of the two openings are different, and the unidirectional flow function can also be achieved, and the flow direction of the unidirectional flow is from the second opening 16 corresponding to the second conduction space 142 with a larger volume flowing in and flowing out from the first opening 15.

[0039] Therefore, when the unidirectional flow driver 100 satisfies the above condition 1 and at least one of condition 2 and condition 3, the pressure changes generated by the up and down vibration of the cantilever driver 22 on the first conduction space 141 and the second conduction space 142 are different, resulting in different partial pressures at the opening 1 and the opening 2, thus achieving the unidirectional flow function. Specifically, for the conduction space on the side with a smaller volume, the pressure change during compression is greater than that of the conduction space on the side with a larger volume. Therefore, it has a greater partial pressure during the compression cycle, and the fluid escaping from the opening corresponding to this side is greater than that from the opening corresponding to the conduction space on the side with a larger volume.

[0040] As Figure 5As shown, under the above mechanism, after the fluid state stabilizes, as the cantilever actuator 22 reciprocates, the net flow direction of the fluid at both openings changes back and forth. However, the net flow direction of the opening corresponding to the smaller volume conduction space tends to flow out of the conduction space (biased relative to the zero point outward direction), while the net flow direction of the opening corresponding to the larger volume conduction space tends to flow into the conduction space (biased relative to the zero point inward direction).

[0041] like Figure 6 As shown, after the fluid state stabilizes, although the flow direction of the system changes periodically, the overall net flow rate is always pulsed, drawn in from the opening on the larger volume side, flowing out through the cantilever gap 24 from the opening on the smaller volume side. The inlet and outlet velocities are constantly changing direction periodically, resulting in a pulsed unidirectional flow.

[0042] Furthermore, in this embodiment, the diameter of the cantilever gap is greater than 5 micrometers, thereby preventing the fluid velocity from decreasing due to the viscosity effect of the fluid in the channel caused by the cantilever gap being too small.

[0043] For further details, please refer to Figure 2 In the unidirectional flow driver 100 provided in this embodiment, the housing 1 includes a first connecting plate 12 in an annular shape, and a second connecting plate and a third connecting plate 13 fixed to opposite ends of the first connecting plate 12. The first connecting plate 12, the second connecting plate 11, and the third connecting plate 13 are connected and together form the cavity 14. The first opening 15 is disposed through the second connecting plate 11, and the second opening 16 is disposed through the third connecting plate 13. The control unit 2 includes a first base 21 and a cantilever driver 22. The first base 21 is abutted and fixed to one side of the first connecting plate 12, and the cantilever driver 22 is spaced apart from the other side of the first connecting plate 12 to form the cantilever gap 24.

[0044] Or such as Figure 1As shown, the housing 1 includes a first connecting plate 12 in an annular shape, and a second connecting plate and a third connecting plate 13 fixed to opposite ends of the first connecting plate 12. The first connecting plate 12, the second connecting plate 11, and the third connecting plate 13 are connected and together form the cavity 14. The first opening 15 is disposed through the second connecting plate 11, and the second opening 16 is disposed through the third connecting plate 13. The control unit 2 includes two first bases 21 and two cantilever actuators 22. The two first bases 21 are respectively abutted and fixed to opposite sides of the first connecting plate 12. One end of each of the two cantilever actuators 22 is fixed to the two first bases 21, and the other ends of the two cantilever actuators 22 are opposite to each other and spaced apart to form the cantilever gap 24.

[0045] The thickness of the cantilever actuator 22 also has a certain impact on unidirectional flow control. Generally speaking, when other parameters are constant, the greater the thickness of the cantilever actuator 22, the higher the efficiency of unidirectional flow. Therefore, in this embodiment, the thickness of the cantilever actuator 22 is greater than the thickness of the second connecting plate 11 and the third connecting plate 13. The greater thickness of the cantilever actuator 22 can increase the intrinsic frequency, thereby increasing the number of vibrations per unit time and improving the efficiency of unidirectional flow.

[0046] Specifically, in the first conductive space 141, the distance between the first base 21 and the first connecting plate 12 on the opposite side is defined as L4, and in the second conductive space 142, the distance between the two first connecting plates 12 is defined as L5. It can be seen that L4 and L5 are both greater than or equal to the effective length (i.e., the part that can vibrate) of the cantilever actuator 22.

[0047] In this embodiment, please refer to Figure 7 The unidirectional flow driver 100 further includes a second base 23 located in the second conductive space 142. The second base 23 and the first base 21 are arranged opposite to each other along the vibration direction of the cantilever driver 22. The fixed end of the cantilever driver 22 is fixed between the second base 23 and the first base 21.

[0048] For this implementation method, please refer to Figure 8 The first connecting plate 12 further includes an extension 121 extending along the extending direction of the cantilever actuator 22. The extension 121 is located within the second conductive space 142, and the fixed end of the cantilever actuator 22 is clamped and fixed between the extension 121 and the first base 21. This design can increase the fixation stability of the cantilever actuator 22.

[0049] For this implementation method, please refer to Figure 9The unidirectional flow driver 100 may also be provided with a third opening 17 through the first connecting plate 12, the third opening 17 being connected to the second conductive space 142, and the third opening 17 being spaced apart from the second opening 16.

[0050] Please see Figure 10 A third opening 17 and a fourth opening 18 are respectively formed through the two first connecting plates 12. Both the third opening 17 and the fourth opening 18 are connected to the second conductive space 142. The centers of the third opening 17 and the fourth opening 18 coincide in the extension direction of the cantilever driver 22.

[0051] There may be more than just the first opening 15 and the second opening 16. When the first opening 15, the second opening 16, and the cantilever gap 24 have an overlapping relationship with each other in the vibration direction of the cantilever actuator 22, it is also feasible to add other openings to the first connecting plate 12 of the second conductive space 142. For example, a third opening 17 and a fourth opening 18 can be provided on the first connecting plate 12 to achieve the function of unidirectional flow.

[0052] In this embodiment, the effective length (i.e., the vibrating portion) of the cantilever actuator 22 needs to meet certain requirements to achieve unidirectional flow control. Generally speaking, the unidirectional flow control effect is better when the effective length of the cantilever actuator 22 is greater than 0.1 mm.

[0053] In this embodiment, when the cantilever actuator 22 is driven to vibrate along a direction perpendicular to the extension of the cantilever actuator 22, the amplitude of the cantilever actuator 22 is ≥1µm.

[0054] In this embodiment, the operating frequency of the control unit 2 is greater than 20 kHz. For the cantilever actuator 22, a higher operating frequency f0 (drive signal) is beneficial for the fluid to form a high-speed unidirectional flow and can also reduce operating noise.

[0055] Please see Figure 11 The control unit 2 includes at least two units arranged in a linear array within the housing 1. The cantilevered actuators 22 of all the control units 2 together divide the cavity 14 into the first conductive space 141 and the second conductive space 142. The number of the first opening 15 and the second opening 16 is the same as the number of the control units 2. Each control unit 2 is matched with one first opening 15 and one second opening 16.

[0056] Specifically, the unidirectional flow driver 100 of the present invention can be not just a single control unit 2, but also an array composed of multiple control units 2. This embodiment illustrates a device that is arrayed using the above-described unit structure; this embodiment is an array device implemented using a structure of paired cantilever drivers 22 as array units. A structure of a single cantilever driver 22 can also be used as an array unit, which will not be elaborated here.

[0057] In this embodiment, the cantilever actuators 22 within the same control unit 2 have the same initial vibration phase and the same vibration frequency. Controlling the cantilever actuators 22 within the same control unit 2 to have the same initial vibration phase and the same vibration frequency avoids interference between the cantilever actuators 22 within the same control unit 2. Optionally, the present invention does not limit the fluid; the fluid can be liquid, gas, or sound waves, etc. Furthermore, the unidirectional flow actuator 100 of the present invention can be applied to heat dissipation, air pumps, microfluidics, and loudspeakers, etc.

[0058] Specifically, the unidirectional flow driver 100 of the present invention is used as a heat sink in the following scenarios: Figure 12 As shown, when the unidirectional flow driver 100 controls the fluid to flow from the first opening 15 to the second opening 16, the object requiring heat dissipation (such as a CPU chip) is placed on one side of the second opening 16, perpendicular to the air outlet direction of the second opening 16. Driven by the unidirectional flow driver 100, cool air flows in from one side of the first opening 15, passes through the cantilever gap 24, and flows out from one side of the second opening 16, blowing onto the surface of the heat-generating object 200, thereby efficiently removing its heat and achieving active heat dissipation.

[0059] Example 2 Please refer to the appendix. Figure 13-14 As shown, this embodiment of the invention provides a method for manufacturing a unidirectional flow actuator as described above. The manufacturing method is a MEMS manufacturing process, which includes the following steps: A silicon-on-insulator (SiI) wafer is provided, comprising, from bottom to top, a substrate layer 28 (composed of monocrystalline silicon), a buried oxide layer 29 (composed of silicon dioxide), and a device layer 30 (composed of monocrystalline silicon, typically thinner than the substrate layer 28). The substrate layer 28 of the SiI wafer will subsequently be fabricated as a first substrate 21. A cantilever gap 24 and a cantilever beam 311 are fabricated on the device layer 30 of silicon-on-insulator using MEMS processes such as photolithography and etching. A first metal electrode 26, a piezoelectric thin film 27 and a second metal electrode 25 are sequentially deposited on the cantilever beam 311 and patterned using MEMS processes such as photolithography and etching to obtain the cantilever actuator 22. The structure above device layer 30 is protected using a temporary bonding process or by spin-coating photoresist. The area between the substrate layer 28 and buried oxide layer 29 below the cantilever driver 22 is removed on the back side of the silicon-on-insulator wafer using photolithography, etching, and other processes, forming the first conductive space 141. The peripheral area of ​​the substrate layer 28 and buried oxide layer 29 forms the first base 21. Release the temporary bonding / or remove the photoresist on the upper surface of device layer 30 to complete the MEMS wafer fabrication process; The MEMS wafer is divided using laser scribing and / or mechanical scribing processes to obtain individual MEMS chips. A second connecting plate 11 made of a printed circuit board is provided, and a first opening 15 is formed through the second connecting plate 11. One side of the substrate layer 28 of the MEMS chip is fixed to the second connecting plate 11; A housing 1 with a cavity 14 is provided, and a second opening 16 is formed through the housing 1, and the housing 1 is covered and fixed on the second connecting plate 11.

[0060] The cantilever actuator 22 divides the cavity 14 to form a first conductive space 141 and a second conductive space 142. The first conductive space 141 is connected to the first opening 15, and the second conductive space 142 is connected to the second opening 16. Any two of the first opening 15, the second opening 16, and the cantilever gap 24 at least partially overlap in the vibration direction of the cantilever actuator 22.

[0061] In this embodiment, the second connecting plate 11 is a printed circuit board (PCB); the first base 21 is fabricated based on the silicon substrate layer 28 of an SOI (Silicon on Isolation) wafer, and the cantilever driver 22 is fabricated based on the device layer 30 of the SOI wafer. The SOI wafer substrate layer 28 (handle layer) is used as the anchor point for the chip.

[0062] Specifically, piezoelectric actuation is achieved through a piezoelectric thin film 27. A first base 21 is mounted on a second connecting board 11 of the PCB. The first base 21, cantilever actuator 22, first metal electrode 26, piezoelectric thin film 27, and second metal electrode 25 of the control unit 2 are sequentially stacked and fixedly connected. The length of the first metal electrode 26 is equal to that of the cantilever actuator 22, and the length of the second metal electrode 25 is less than that of the first metal electrode 26. By encapsulating the MEMS chip on the second connecting board 11, electrical connection can be achieved through wire bonding.

[0063] In this embodiment, the PCB board has openings to realize the first opening 15 and the second opening 16 are realized by openings on the housing 1; the MEMS chip structure can also be surface mounted on the PCB board through SMT process. At that time, the spatial positions of the PCB board, MEMS chip and housing 1 will change accordingly. However, as long as the final assembly result conforms to the structure described above in the proposal, it is within the scope of protection of this proposal, and will not be elaborated here.

[0064] In this embodiment, the piezoelectric thin film 27 is made of any one of the following piezoelectric materials: PZT (lead zirconate titanate), AlN (aluminum nitride), AlScN (scandium aluminum nitride), KNN (potassium sodium niobate), and ZnO (zinc oxide). PZT is the most commonly used piezoelectric ceramic, exhibiting excellent piezoelectric properties and widely used in sensors, transducers, etc. AlN has good insulation and high-temperature resistance, and is often used in RF filters and MEMS devices. AlScN is a modified AlN material; the addition of scandium significantly improves its piezoelectric properties. KNN is a lead-free piezoelectric material, environmentally friendly, and can replace some PZT applications. ZnO is a semiconductor piezoelectric material, easily prepared into thin films, and used in flexible electronics, sensors, etc.

[0065] Example 3 Please see the appendix Figure 15-16 As shown, this embodiment of the invention provides a method for manufacturing the unidirectional flow driver 100 as described above. The manufacturing method is a machining method, which includes the following steps: A substrate 31 is provided, a cantilever gap 24 and a cantilever beam 311 are processed on the substrate 31, and a piezoelectric ceramic sheet 32 ​​is attached to the cantilever beam 311 to obtain a cantilever actuator 22.

[0066] An upper frame 4 with a first through hole 41 and a lower frame 5 with a second through hole 51 are provided, and the upper frame 4 and the lower frame 5 are respectively attached to opposite sides of the substrate 31; wherein, the thickness of the lower frame 5 is the thickness of the first conductive space 141, and the thickness of the upper frame 4 is the thickness of the second conductive space 142.

[0067] A top cover 6 and a bottom cover 7 are provided. The top cover 6 is attached to the side of the upper frame 4 away from the lower frame 5, and the bottom cover 7 is attached to the side of the lower frame 5 away from the upper frame 4. The bottom cover 7, the lower frame 5 and the substrate 31 together form the first conductive space 141, and the top cover 6, the upper frame 4 and the substrate 31 together form the second conductive space 142. The lower frame 4 is set as the first base 21.

[0068] A first opening 15 and a second opening 16 are respectively provided on the bottom cover 7 and the top cover 6. The first opening 15, the second opening 16 and the cantilever gap 24 are interconnected, and any two of the first opening 15, the second opening 16 and the cantilever gap 24 at least partially overlap in the vibration direction of the cantilever actuator 22.

[0069] Specifically, a cantilever actuator 22 is constructed by machining a cantilever gap 24 and a cantilever beam 311 on a substrate 31 with a high Young's modulus (such as stainless steel), and attaching a piezoelectric ceramic sheet 32 ​​to the cantilever beam 311. A pair of cantilever actuators 22 are arranged symmetrically with an appropriate gap in the middle to form the cantilever gap 24. The upper frame 4 and the lower frame 5 are respectively attached to the upper and lower sides of the substrate 31 to define the thickness of the first conductive space 141 and the second conductive space 142; the top cover 6 and the bottom cover 7 are respectively attached to the upper side of the upper frame 4 and the lower side of the lower frame 5, together with the upper frame 4 and the lower frame 5 to construct the first conductive space 141 and the second conductive space 142; at the same time, the top cover 6 and the bottom cover 7 each have an opening of a predetermined diameter.

[0070] Optionally, this figure is only a schematic diagram and omits the terminals required to drive the piezoelectric ceramic, as well as the slots left for the terminals leading out on the upper frame 4.

[0071] Compared with related technologies, this invention sets any two of the first opening, second opening, and cantilever gap to at least partially overlap in the vibration direction of the cantilever actuator, forming a straight-through structure of the first opening, second opening, and cantilever gap. This reduces fluid flow resistance and path deflection, improves unidirectional flow efficiency, and achieves this by setting the following three conditions: Condition 1 is that the volumes of the first and second conductive spaces are different; Condition 2 is that the diameters of the first and second openings are equal; and Condition 3 is that the diameter of the cantilever gap is smaller than the diameters of the first and second openings. This invention limits the unidirectional flow actuator to satisfy Condition 1 and at least one of Conditions 2 and 3. This results in different pressure distributions in the first and second conductive spaces, different flow resistances in the two openings, and thus achieves unidirectional fluid flow. This invention has a simple structure that is easy to manufacture, avoids the use of various active or passive valves, has a short flow path, and utilizes the dimensional relationships of the structural components to achieve high-flow-rate unidirectional flow and significantly improves long-term operational reliability.

[0072] The above description is merely an embodiment of the present invention. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of the present invention, but these improvements all fall within the protection scope of the present invention.

Claims

1. A unidirectional flow actuator, the unidirectional flow actuator comprising a housing having a cavity and at least one control unit located within the housing, characterized in that... ； The control unit divides the cavity into a first conductive space and a second conductive space; the housing is provided with a first opening and a second opening that pass through it, the first opening communicating with the first conductive space and the second opening communicating with the second conductive space; The control unit includes a first base fixed inside the housing and a cantilever actuator fixed to the first base. The cantilever actuator divides the cavity into a first conductive space and a second conductive space. The first base is disposed within the first conductive space. One end of the cantilever actuator is fixed to the first base, and the other end of the cantilever actuator forms a cantilever gap. The cantilever gap connects the first conductive space and the second conductive space, allowing fluid to flow in from one of the first opening and the second opening and out from the other of the first opening and the second opening. Any two of the first opening, the second opening, and the cantilever gap overlap at least partially in the vibration direction of the cantilever actuator; Among them, the following three conditions are set: Condition 1 is that the volume of the first conductive space and the volume of the second conductive space are different; Condition 2 is that the diameter of the first opening is equal to the diameter of the second opening; Condition 3 is that the diameter of the cantilever gap is smaller than the diameters of the first opening and the second opening; The unidirectional flow driver satisfies condition 1, and at least one of conditions 2 and 3.

2. The unidirectional flow driver according to claim 1, characterized in that, The diameter of the cantilever gap is greater than 5 micrometers.

3. The unidirectional flow driver according to claim 1, characterized in that, When the volume of the first conductive space and the volume of the second conductive space are different, and the diameter of the first opening is equal to the diameter of the second opening, the fluid flows in from the opening corresponding to the larger conductive space in the first and second conductive spaces, and flows out from the opening corresponding to the smaller conductive space in the first and second conductive spaces.

4. The unidirectional flow driver according to claim 1, characterized in that, The housing includes a first connecting plate in an annular shape, and a second connecting plate and a third connecting plate fixed to opposite ends of the first connecting plate; the first connecting plate, the second connecting plate and the third connecting plate are connected and together form the cavity; the first opening is disposed through the second connecting plate, and the second opening is disposed through the third connecting plate; the control unit includes a first base and a cantilevered actuator, the first base is abutted and fixed to one side of the first connecting plate, and the cantilevered actuator is spaced apart from the other side of the side plate to form the cantilever gap.

5. The unidirectional flow driver according to claim 4, characterized in that, The first connecting plate further includes an extension portion extending along the extension direction of the cantilever driver, the extension portion being located within the second conductive space, and the cantilever driver being clamped and fixed between the extension portion and the first base.

6. The unidirectional flow driver according to claim 1, characterized in that, The unidirectional flow driver further includes a third opening formed through the first connecting plate, the third opening being connected to the second conductive space, and the third opening being spaced apart from the second opening.

7. The unidirectional flow driver according to claim 1, characterized in that, The unidirectional flow actuator further includes a second base located in the second conductive space. The second base and the first base are arranged opposite to each other in the vibration direction of the cantilever actuator. The cantilever actuator is clamped and fixed between the first base and the second base.

8. The unidirectional flow driver according to claim 1, characterized in that, The housing includes a first connecting plate in an annular shape, and a second connecting plate and a third connecting plate fixed to opposite ends of the first connecting plate; the first connecting plate, the second connecting plate and the third connecting plate are connected and together form the cavity; the first opening is disposed through the second connecting plate, and the second opening is disposed through the third connecting plate; the control unit includes two first bases and two cantilever actuators, the two first bases are respectively abutted and fixed to opposite sides of the side plate, one end of the two cantilever actuators is respectively fixed to the two first bases, and the other ends of the two cantilever actuators are opposite to each other and spaced apart to form the cantilever gap.

9. The unidirectional flow driver according to claim 1, characterized in that, The unidirectional flow driver further includes a third opening and a fourth opening formed through the first connecting plate. Both the third opening and the fourth opening are connected to the second conductive space. The centers of the third opening and the fourth opening coincide in the extension direction of the cantilever driver.

10. The unidirectional flow driver according to claim 1, characterized in that, The operating frequency of the control unit is greater than 20KHz.

11. The unidirectional flow driver according to claim 8, characterized in that, The control unit includes at least two arranged in a linear array within the housing. The cantilevered actuators of all the control units together divide the cavity into a first conductive space and a second conductive space. The number of the first opening and the number of the second opening are the same as the number of the control units, and each control unit is matched with one first opening and one second opening.

12. A method for manufacturing a unidirectional flow actuator as described in any one of claims 1-11, characterized in that, The manufacturing method is a machining method, which includes the following steps: A substrate is provided, on which a cantilever gap and a cantilever beam are processed, and a piezoelectric ceramic sheet is attached to the cantilever beam to obtain a cantilever actuator; A top frame with a first through hole and a bottom frame with a second through hole are provided, and the top frame and the bottom frame are respectively attached to opposite sides of the substrate; A top cover and a bottom cover are provided. The top cover is attached to the side of the upper frame away from the lower frame, and the bottom cover is attached to the side of the lower frame away from the upper frame. The bottom cover, the lower frame and the substrate together form a first conductive space, and the top cover, the upper frame and the substrate together form a second conductive space. The lower frame is set as a first base. A first opening and a second opening are respectively pre-set on the bottom cover and the top cover. The first opening, the second opening and the cantilever gap are interconnected, and any two of the first opening, the second opening and the cantilever gap at least partially overlap in the vibration direction of the cantilever actuator.

13. A method for manufacturing a unidirectional flow actuator as described in any one of claims 1-11, characterized in that, The manufacturing method is a MEMS manufacturing process, which includes the following steps: A silicon-on-insulator (SiI) wafer is provided, comprising, from bottom to top, a substrate layer, a buried oxide layer, and a device layer, wherein the substrate layer and the device layer are composed of monocrystalline silicon, the buried oxide layer is composed of silicon dioxide, and the thickness of the device layer is less than the thickness of the substrate layer. The cantilever gap and cantilever beam are fabricated on the device layer by photolithography and etching processes; a first metal electrode, a piezoelectric thin film and a second metal electrode are sequentially deposited on the cantilever beam to obtain the cantilever actuator; The intermediate region between the substrate layer and the buried oxide layer is removed by photolithography and etching processes to form the first conductive space. The outer regions of the substrate layer and the buried oxide layer form the first base, thus obtaining a MEMS chip. A base plate made of a printed circuit board is provided, and a first opening is formed through the base plate; The substrate layer of the MEMS chip is fixed to the base plate; A housing with a cavity is provided, and a second opening is formed through the housing, and the housing is covered and fixed on the base plate; The cantilever actuator divides the cavity into a first conductive space and a second conductive space. The first conductive space is connected to the first opening, and the second conductive space is connected to the second opening. Any two of the first opening, the second opening, and the cantilever gap at least partially overlap in the vibration direction of the cantilever actuator.

14. The method for manufacturing a unidirectional flow actuator according to claim 13, characterized in that, The piezoelectric thin film is made of any one of the piezoelectric materials selected from PZT, AlN, AlScN, KNN, and ZnO.

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