Airflow generating device with differential modulation drive and asymmetric initial deflection

Abstract

An airflow generating device includes a first unit disposed in a first region and a second unit disposed in a second region. The first unit and the second unit are correspondingly disposed. The first unit generates a first air pressure having a first polarity in the first region, and the second unit generates a second air pressure having a second polarity in the second region. The second polarity is opposite to the first polarity. At least one of the first unit and the second unit includes a membrane structure, the membrane structure including a pair of flaps, the flap pair including a first flap and a second flap opposite to each other. The flap pair has an initial deflection difference or exhibits an average displacement difference between the first flap and the second flap. The flap pair operates at an ultrasonic frequency, causing the airflow generating device to generate a plurality of air pulses at an ultrasonic pulse rate.

Description

Technical Field

[0001] The present invention relates to an airflow generating device, and more particularly to an airflow generating device capable of providing a significant airflow. Background Technology

[0002] Unless otherwise specified, the practices described below are not prior art to the claims of this application, and the contents of this paragraph should not be included in the prior art.

[0003] Air-pulse generating (APG) devices have been developed to generate air pulses. Besides audio applications, APG devices can also provide airflow applications. In recent years, APG devices manufactured using Micro-Electro-Mechanical Systems (MEMS) have attracted significant market attention due to their small size and ability to generate airflow. The market demand for strong airflow is growing to improve performance in areas such as heat dissipation. However, providing strong airflow remains a challenge for miniature devices manufactured using MEMS.

[0004] Therefore, designing MEMS devices that can provide significant airflow is a pressing issue in this field. Summary of the Invention

[0005] Therefore, the present invention mainly provides an airflow generating device to improve the shortcomings of the prior art.

[0006] This invention provides an airflow generating device, including a first unit disposed in a first region and a second unit disposed in a second region, the first unit and the second unit being correspondingly disposed therein; wherein the first unit generates a first air pressure having a first polarity in the first region, and the second unit generates a second air pressure having a second polarity in the second region; wherein the second polarity is opposite to the first polarity; wherein at least one of the first unit and the second unit includes a membrane structure, the membrane structure including a pair of lobes, the pair of lobes including a first lobe and a second lobe facing each other; wherein the pair of lobes has an initial deflection difference or exhibits an average displacement difference between the first lobe and the second lobe; wherein the pair of lobes operates at an ultrasonic frequency, such that the airflow generating device generates a plurality of air pulses at an ultrasonic pulse rate. Attached Figure Description

[0007] Figure 1 This is a top view schematic diagram of an airflow generating device according to an embodiment of the present invention.

[0008] Figure 2 This is a cross-sectional schematic diagram of an airflow generating device according to an embodiment of the present invention.

[0009] Figure 3 This is a schematic diagram of the diaphragm motion of an airflow generating device according to an embodiment of the present invention.

[0010] Figure 4 This is a schematic diagram of the driving signal according to an embodiment of the present invention.

[0011] Figure 5 This is a schematic diagram of an airflow generating device according to an embodiment of the present invention.

[0012] Figure 6 This is a schematic diagram of an airflow generating device according to an embodiment of the present invention.

[0013] Figure 7 This is a schematic diagram of an airflow generating device according to an embodiment of the present invention.

[0014] Figure 8 This is a schematic diagram of the appearance of an airflow generating device according to an embodiment of the present invention.

[0015] Figure 9 This is a schematic diagram of an airflow generating device according to an embodiment of the present invention.

[0016] Figure 10 This is a schematic diagram of an airflow generating device according to an embodiment of the present invention.

[0017] Figure 11 This is a schematic diagram of an airflow generating device according to an embodiment of the present invention.

[0018] Figure 12 This is a schematic diagram of a gas pulse generating device according to an embodiment of the present invention.

[0019] Figure 13 This is a cross-sectional schematic diagram of an airflow generating device according to an embodiment of the present invention.

[0020] Figure 14 This is a schematic diagram of a signal waveform according to an embodiment of the present invention.

[0021] Figure 15 This is a schematic diagram of the appearance of an airflow generating device according to an embodiment of the present invention.

[0022] Explanation of reference numerals in the attached figures: 1, 1', 2, 2', 3, 34, 4, 5, 6, 8, 44: Airflow generating device 10, 20, 30, 40: Units 10f, 20f: Membrane structures 10p, 102, 20p, 41v, 42m, 43v, 51v, 52m, 53m, 54m, 55v, 61v, 62m, 63m, 64v: Pebble pairs 101, 103, 201, 203: Petals 101A, 103A, 201A, 203A: Actuators 112, 212: Virtual valves 12: Opening 140, 340, 440: Cover structure 7: APG device 9a, 9b: Driver Scheme LV: Horizontal plane RG1, RG2: Swing range Rg1, Rg2: Regions rg11, rg12, rg21, rg22: Subregions AF1, AF2, AF3, AF4: Airflow P+, P-: Air pressure , , , , , , , , , , Time point SM1, SM2, +SV1, -SV1, +SV2, -SV2, SM1, SM2, SV1a, SV1b, SV2a, SV2b: Signals S1, S2: States Tcy: Period U z,101 U z,103 U z,201 U z,203 Displacement VB1, VB2, VB3: Bias voltage X, Y, Z, X1, X2: Coordinate directions 0,101 , 0,103 Initial position ,101 , ,103 , ,101 , ,103 : Location Detailed Implementation

[0023] The contents of U.S. Patent No. 12,356,141 and U.S. Application No. 19 / 424,094 are incorporated herein by reference in their entirety and form part of this specification.

[0024] Figure 1 This is a top view schematic diagram of an airflow generating device 1 (particularly the diaphragm portion) according to an embodiment of the present invention. Figure 2 This is a cross-sectional schematic diagram of an airflow generating device 1 (particularly the diaphragm portion) according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the membrane movement of an airflow generating device 1 (including a cover structure 140) according to an embodiment of the present invention. The airflow generating device 1 includes a first unit 10 and a second unit 20. Units 10 and 20 are both air-pulse generating (APG) devices manufactured using MicroElectroMechanical Systems (MEMS) technology, and their structures are similar to those described in US Patent No. 12,356,141. The first unit 10 is disposed in a first region Rg1 (or region 1), and the second unit 20 is disposed in a second region Rg2 (or region 2). As described below, the present invention utilizes one or more cells in region 1 and one or more cells in region 2 to generate an air pressure difference, thereby generating airflow.

[0025] Specifically, unit 10 or 20 includes a membrane structure (or diaphragm) 10f or 20f. Figure 1 In the embodiments shown, the film structure 10f or 20f includes a flap pair 10p or 20p, and the flap pair 10p or 20p includes a first flap 101 or 201 and a second flap 103 or 203 disposed opposite to each other.

[0026] The 10p or 20p slice pair can receive common-mode signals SM1 or SM2 (also known as modulation driving signals) for (first or second) common-mode motion. The 10p or 20p slice pair can also receive a pair of differential-mode signals ±SV1 or ±SV2 for (first or second) differential-mode motion. Figure 1 and Figure 2In the illustrated embodiment, the flaps simultaneously perform common-mode and differential-mode motions at 10p or 20p. In practice, the diaphragm motion of the flaps at 10p or 20p can be considered as a superposition or combination of common-mode and differential-mode motions.

[0027] In one embodiment, such as Figure 2 As shown, the 10p or 20p flaps receive differential mode signals ±SV1 or ±SV2 through multiple top electrodes of the corresponding multiple actuators, and receive common mode signals SM1 or SM2 through multiple bottom electrodes of the corresponding multiple actuators.

[0028] For a first virtual valve 112 or a second virtual valve 212, the flaps 10p or 20p, having oppositely arranged flaps 101 or 201 and flaps 103 or 203, perform a first or second differential mode movement. When the displacement difference between flaps 101 or 201 and flaps 103 or 203 is greater than the flap thickness or diaphragm thickness, the first virtual valve 112 or the second virtual valve 212 is considered "open". When the displacement difference between flaps 101 or 201 and flaps 103 or 203 is less than the flap thickness or diaphragm thickness, the first virtual valve 112 or the second virtual valve 212 is considered "closed".

[0029] In one embodiment, as described in U.S. Patent No. 12,356,141, the virtual valve is closed during the transition of differential mode motion. This means that the virtual valve is closed during the transition time period when the first and second flaps are in differential mode motion, but is not limited thereto. In one embodiment, the virtual valve may be closed corresponding to the reversal of the flap or diaphragm motion under differential mode motion, which is also within the scope of this invention.

[0030] The operating principles of each unit can be found in US Patent No. 12,356,141, but are not limited thereto.

[0031] Figure 3 A cover structure 140 for covering a pair of 10p or 20p lobes is shown. In the cover structure 140, an opening 12 is formed between a first region Rg1 and a second region Rg2. The opening 12 may be elongated (e.g., ...). Figure 8 (As shown). Figure 1 The projection of opening 12 is also shown, which is located between the first region Rg1 and the second region Rg2.

[0032] Figure 3 The diagram illustrates the diaphragm movement of an airflow generating device 1 according to an embodiment of the present invention at times t1, t2, t3, and t4.

[0033] At time t1, the first unit 10 or the first flap pair 10p undergoes an upward common-mode motion and a first differential-mode motion, causing the first virtual valve 112 to close. The second unit 20 or the second flap pair 20p undergoes a downward common-mode motion and a second differential-mode motion, causing the second virtual valve 212 to open. The upward first common-mode motion compresses the first volume of the first region Rg1 or the first volume above the first region Rg1, creating a positive air pressure P+ within or above the first region Rg1. The downward second common-mode motion expands the second volume of the second region Rg2 or the second volume above the second region Rg2, creating a negative air pressure P- within or above the second region Rg2. The second differential-mode motion causes the second virtual valve 212 to open, thereby allowing airflow AF1 to flow in the +Z direction through openings 212, 12.

[0034] At time t2, the first unit 10 or the first flap pair 10p undergoes a downward first common-mode motion and a first differential-mode motion, causing the first virtual valve 112 to open. The second unit 20 or the second flap pair 20p undergoes an upward second common-mode motion and a second differential-mode motion, causing the second virtual valve 212 to close. The upward second common-mode motion compresses the second volume of the second region Rg2 or the second volume above the second region Rg2, creating a positive air pressure P+ within or above the second region Rg2. The downward first common-mode motion expands the first volume of the first region Rg1 or the first volume above the first region Rg1, creating a negative air pressure P- within or above the first region Rg1. The first differential-mode motion causes the first virtual valve 112 to open, thereby allowing airflow AF2 to flow in the +Z direction through openings 112, 12.

[0035] At time t3, the first unit 10 or the first flap pair 10p undergoes an upward common-mode motion and a first differential-mode motion, causing the first virtual valve 112 to close. The second unit 20 or the second flap pair 20p undergoes a downward common-mode motion and a second differential-mode motion, causing the second virtual valve 212 to open. The upward first common-mode motion compresses the first volume of the first region Rg1 or the first volume above the first region Rg1, creating a positive air pressure P+ within or above the first region Rg1. The downward second common-mode motion expands the second volume of the second region Rg2 or the second volume above the second region Rg2, creating a negative air pressure P- within or above the second region Rg2. The second differential-mode motion causes the second virtual valve 212 to open, thereby allowing airflow AF3 to flow in the +Z direction through openings 212, 12.

[0036] At time t4, the first unit 10 or the first flap pair 10p undergoes a downward common-mode motion and a first differential-mode motion, causing the first virtual valve 112 to open. The second unit 20 or the second flap pair 20p undergoes an upward common-mode motion and a second differential-mode motion, causing the second virtual valve 212 to close. The upward second common-mode motion compresses the second volume of the second region Rg2 or the second volume above the second region Rg2, creating a positive air pressure P+ within or above the second region Rg2. The downward first common-mode motion expands the first volume of the first region Rg1 or the first volume above the first region Rg1, creating a negative air pressure P- within or above the first region Rg1. The first differential-mode motion causes the first virtual valve 112 to open, thereby allowing airflow AF4 to flow in the +Z direction through openings 112, 12.

[0037] Figure 3 The diaphragm motion shown can be achieved by applying Figure 4 This is achieved using the (driving) signals SM1, SM2, ±SV1, and ±SV2 shown. The signal set (SM...) 1 / 2 ±SV 1 / 2 (See US Patent No. 12,356,141.) The differential frequency of the differential signal ±SV can be half (or even a quarter) of the common frequency of the common signal SM.

[0038] exist Figure 4 In the illustrated embodiment, the differential mode signal ±SV1 and the differential mode signal ±SV2 may have a phase difference of π / 4 (but are not limited thereto); the common mode signal SM1 and the common mode signal SM2 may have a phase difference of π / 2 (but are not limited thereto).

[0039] Figures 5 to 7 This is a top view schematic diagram of airflow generating devices 1', 2, 2' and 3 (particularly the diaphragm portion) according to an embodiment of the present invention. Airflow generating devices 1, 1', 2 or 2' may be divided into only two regions. For airflow generating devices 1, 1', 2 or 2', one or more units disposed in region 1 and receiving a first signal set (SM1, ±SV1) can be considered as one or more first units, and one or more units disposed in region 2 and receiving a second signal set (SM2, ±SV2) can be considered as one or more second units.

[0040] exist Figure 5 A slit is formed between the first and second lobes disposed opposite to each other in the first or second unit of the airflow generating device 1'. This slit is perpendicular to the opening 12, and this is also within the scope of the present invention.

[0041] exist Figure 6Region 1 may have multiple first units, and region 2 may have multiple second units. These first or second units may be arranged in an array, which is also within the scope of this invention.

[0042] exist Figure 7 Multiple units receiving a first signal set (SM1, ±SV1) may be adjacent to multiple units receiving a second signal set (SM2, ±SV2) in a first direction (e.g., X1) and a second direction (e.g., X2) (and vice versa), wherein the first direction is perpendicular to the second direction. For example, multiple first units 10 of a sub-region rg11 of region 1 are adjacent to multiple second units 20 of a sub-region rg21 of region 2 in the first direction X1, and multiple first units 10 of sub-region rg11 of region 1 are adjacent to multiple fourth units 40 of a sub-region rg22 of region 2 in the second direction X2 (perpendicular to the first direction X1). Similarly, multiple third units 30 of a sub-region rg12 of region 1 are adjacent to multiple fourth units 40 of sub-region rg22 of region 2 in the first direction X1, and multiple third units 30 of sub-region rg12 of region 1 are adjacent to multiple second units 20 of sub-region rg21 of region 2 in the second direction X2.

[0043] In one embodiment, a plurality of first units in subregion rg11 of region 1 and a plurality of third units in subregion rg12 of region 1 all receive a first signal set (SM1, ±SV1), and a plurality of second units in subregion rg21 of region 2 and a plurality of fourth units in subregion rg22 of region 2 all receive a second signal set (SM2, ±SV2).

[0044] Multiple openings 12 can be provided between region 1 and region 2. Specifically, the openings 12 can be provided between sub-region rg11 of region 1 and sub-region rg21 of region 2, between sub-region rg11 of region 1 and sub-region rg22 of region 2, between sub-region rg12 of region 1 and sub-region rg22 of region 2, and / or between sub-region rg12 of region 1 and sub-region rg21 of region 2.

[0045] Please note, Figure 7 For illustrative purposes only. Each sub-region (e.g., rg11, rg12, rg21, rg22) may include only one unit, which is also within the scope of this invention.

[0046] Figure 8 This is a schematic diagram of the external appearance of an airflow generating device 34 according to an embodiment of the present invention. The airflow generating device 34 includes a cover structure 340 (e.g., a lid). A plurality of openings 12 may be formed in the cover structure 340, and the openings 12 may be elongated shapes. These elongated openings 12 can divide the airflow generating device 34 into sections. Figure 7The sub-regions rg11, rg12, rg21, and rg22 shown are covered by a cover structure 340. Figure 7 The airflow generating device 3 shown is disposed above it to form an airflow generating device 34.

[0047] One advantage of this invention is that the airflow (volume) of the invention can be increased simply by increasing the number of units and arranging these units and openings (especially opening 12) to extend in directions X1 and / or X2. This expansion method is more flexible in design to meet various requirements, and compared with the previous architecture, it is more reliable to assembly errors and easier to implement in an array.

[0048] For example, Figure 15 This is a schematic diagram of the external appearance of an airflow generating device 44 according to an embodiment of the present invention. The airflow generating device 44 includes a cover structure 440 (e.g., a lid). A plurality of openings 12 may be formed in the cover structure 440, and the openings 12 may be elongated. The airflow generating device 44 can be regarded as an extension of the airflow generating device 34.

[0049] Another advantage of the present invention compared to previous designs is that the dual differential mode (e.g., airflow generating device 34) has less ultrasonic energy leakage, which can result in better airflow performance.

[0050] For example, three configurations were compared in the simulation. The simulation considered a unit arrangement similar to airflow generating device 3. The first configuration is "common-mode," where all units receive a common signal set (SM, ±SV) (subscripts omitted here). The second configuration is "differential-mode movement," where units in subregions rg11 and rg22 (e.g., units 10 and 40) receive a first signal set (SM1, ±SV1), while units in subregions rg21 and rg12 (e.g., units 20 and 30) receive a second signal set (SM2, ±SV2). The third configuration is "double-differential-mode," where units in subregions rg11 and rg12 (e.g., units 10 and 30) receive a first signal set (SM1, ±SV1), while units in subregions rg21 and rg22 (e.g., units 20 and 40) receive a second signal set (SM2, ±SV2).

[0051] In the simulations, the "common mode," "differential mode," and "dual differential mode" generated airflow (volume rate) of 45 cc / s, 54 cc / s, and 58 cc / s, respectively. Therefore, in terms of airflow or volume rate performance, the "differential mode" configuration (corresponding to this invention) is superior to the "common mode" (which corresponds to a prior design and can be considered an extension of U.S. Patent No. 12,356,141). Furthermore, the "dual differential mode" configuration is even superior to the "differential mode" configuration. In other words, this confirms that both the "differential mode" and "dual differential mode" configurations improve airflow or volume rate performance compared to existing technologies.

[0052] Please note that in the above embodiment, a pair of petals (simultaneously) undergoes common-mode motion and differential-mode motion, but the present invention is not limited thereto.

[0053] Figures 9 to 11 This is a schematic diagram of the airflow generating devices 4 to 6 according to an embodiment of the present invention.

[0054] exist Figure 9 The airflow generating device 4 includes a pair of flaps 41v, 42m, and 43v. The flap pair 42m (only or primarily) undergoes common-mode motion to push or pull the volume above or below it, thereby creating (especially within the illustrated chamber) a positive air pressure P+ and / or a negative air pressure P-. The flap pairs 41v and 43v (only or primarily) undergo differential-mode motion. The common-mode motion of the flap pair 42m is synchronized with the differential-mode motion of the flap pairs 41v and 43v in time. Therefore, airflow can be generated to flow into or out of the airflow generating device 4.

[0055] In one embodiment, the differential mode frequency can be half or a quarter of the common mode frequency, so that the opening can always be at high or low pressure in the housing chamber, thereby realizing one-direction airflow pumping.

[0056] In one embodiment, the surface of the chamber can be attached to a heat source or a fin structure, so that the air inside the chamber can be heated by an external heat source and blown away, and the heat from the heat source can also be dissipated.

[0057] exist Figure 10 The airflow generating device 5 includes flap pairs 51v, 52m, 53m, 54m, and 55v. The flap pairs 52m, 53m, and 54m (either alone or primarily) undergo common-mode motion to push or pull the volume above them, thereby creating positive air pressure P+ and / or negative air pressure P-. The flap pairs 51v and 55v (either alone or primarily) undergo differential-mode motion, which is synchronized with the common-mode motion.

[0058] The pressure and airflow within the chamber are similar to a forced swirling system, which helps to increase the equivalent heat convection coefficient of the air within the chamber. When the top surface is attached to a heat source, it helps to expel higher temperatures.

[0059] exist Figure 11 The airflow generating device 6 includes flap pairs 61v, 62m, 63m, and 64v. The flap pairs 62m and 63m (either alone or primarily) undergo common-mode motion to push or pull the air above them, thereby creating a positive air pressure P+ or a negative air pressure P-. The flap pairs 61v and 64v (either alone or primarily) undergo differential-mode motion, which is synchronized with the common-mode motion.

[0060] Utilizing the acoustic modes within the chamber, two push-pull flap pairs, 62m and 63m, can drive the chamber pressure to acoustic resonance. Airflow is generated by synchronizing the valve opening time with the ultrasonic acoustic pressure difference. Having an even number of flap pairs performing common-mode motion (e.g., 62m and 63m) or an even number of flap pairs performing differential-mode motion (e.g., 61V and 64V) facilitates energy recycling in the electrical / mechanical / acoustic domains, thereby improving system efficiency.

[0061] Furthermore, in order to achieve better drive and airflow generation efficiency, U.S. Patent Application No. 19 / 424,094 discloses and illustrates... Figure 12 The asymmetric initial deflection of the APG device can be incorporated into the airflow generating device of the present invention, the relevant content of which is incorporated herein by reference in its entirety and becomes part of this specification.

[0062] Figure 12 A schematic diagram of an APG device 7 according to an embodiment of the present invention is shown. The APG device 7 includes a membrane structure 12, which includes a pair of flaps 102. The pair of flaps 102 includes a first flap 101 and a second flap 103 disposed opposite to each other. Figure 12 As shown, (in most cases,) the first lobe 101 is actuated to bend upward (in the +Z direction or above the horizontal plane LV), while the second lobe 103 is actuated to bend downward (in the –Z direction or below the horizontal plane LV).

[0063] The lobes 102 have an initial deflection difference, or exhibit an average displacement difference between lobes 101 and 103, wherein the initial deflection difference or the average displacement difference is greater than the thickness of the membrane structure 12. For example... Figure 12 As shown, the lobes 101 are initially deflected to an initial position. 0,101 The lobes 103 initially deflect to an initial position. 0,103 In addition, the lobes 101 can be positioned... min,101 and max,101 The range RG1 is an oscillation, which can be expressed as RG1 = [ min,101 , max,101 The lobes 103 can be positioned... min,103 and max,103 The range RG2 can be expressed as RG2 = [ min,103 , max,103 Here, ,x This can be viewed as the position (angular position) of the tip of the flap x relative to its anchor point. When flap 101 swings to this position... min,101 And the petal 103 swings to position max,103 At this time, virtual valve 112 is considered closed. In one embodiment, the position... min,101 and max,103 Can be with Figure 12 The horizontal plane LV is shown. The swing range RG1 of the petal 101 is (substantially) above the horizontal plane LV, while the swing range RG2 of the petal 103 is (substantially) below the horizontal plane LV.

[0064] As described in the applicant's APG device, the flap pair 102 operates at an ultrasonic rate, causing the airflow generating device to generate multiple air pulses at an ultrasonic pulse rate. The flap pair 102 performs differential mode motion to form a virtual valve or opening at an opening frequency, and performs common mode motion to generate ultrasonic air pressure variation.

[0065] Unlike APG devices with symmetrical deflection, for APG devices with asymmetrical deflection (e.g., APG device 7), the common-mode frequency F corresponding to the common-mode motion is... M With the differential mode frequency F corresponding to the differential mode motion V Equal, i.e., F V =F M , of which F V It can be the turn-on frequency, and the frequency F V and F M This can be the ultrasonic pulse rate. Furthermore, to achieve resonance gain, the common-mode frequency F... M and differential mode frequency F V All are close to the resonant frequency Fr of the 102-piece pair, i.e., F V =F M ≈Fr. Here, "approach" refers to the frequency F. V or F M A displacement gain or resonance gain (e.g., 10 times or more) can be obtained by closely approximating the resonant frequency Fr. In practice or in general, a resonance gain of 20 to 30 times (or higher) is sought, but it is not limited to this.

[0066] In this paper, the common-mode frequency F M and differential mode frequency F V These can refer to the frequency of the common-mode signal (also known as the modulation drive signal) SM and the frequency of the differential-mode signal (also known as the demodulation drive signal) SV, respectively.

[0067] Figure 13 This is a cross-sectional schematic diagram of an airflow generating device 8 (particularly the diaphragm portion) according to an embodiment of the present invention. Figure 13 The airflow generating device 8 shown (especially on the static membrane structure) is similar to Figure 2 The airflow generating device 1 is shown. Some of the symbols used for airflow generating device 1 are also used for airflow generating device 8. The difference between airflow generating device 1 and 8 lies in their driving scheme or dynamic diaphragm movement. Figure 14The drive scheme 9a or 9b for the airflow generating device 8 is shown.

[0068] like Figure 13 As shown, the airflow generating device 8 includes units 10 and 20. Unit 10 or 20 includes a membrane structure (or diaphragm) 10f or 20f, the membrane structure 10f or 20f including a pair of flaps 10p or 20p, and the pair of flaps 10p or 20p including a first flap 101 or 201 and a second flap 103 or 203 disposed opposite to each other. The airflow generating device 8 also includes actuators 101A, 103A, 201A or 203A disposed on the flaps 101, 103, 201 or 203. Figure 13 In the illustrated embodiment, the top electrodes of actuators 101A, 103A, 201A, and 203A respectively receive differential mode signals SV1a, SV1b, SV2a, and SV2b. The bottom electrode of actuator 101A or 103A receives common mode signal SM1. The bottom electrode of actuator 201A or 203A receives common mode signal SM2. The (drive) signals SV1a, SV1b, SV2a, SV2b, SM1, and SM2 are as follows: Figure 14 As shown.

[0069] Visors 101 and 103 are driven by differential mode signals SV1a and SV1b, respectively, to form virtual valve 112; visors 201 and 203 are driven by differential mode signals SV2a and SV2b, respectively, to form virtual valve 212. The differential mode signal SV1a or SV2a includes a bias voltage VB1, while the differential mode signal SV1b or SV2b includes a bias voltage VB2. To maintain the initial deflection, the bias voltages VB1 and VB2 are not the same, i.e., VB1 ≠ VB2.

[0070] At time T 22 The differential mode signal SV1a has a negative polarity relative to the bias voltage VB1, and the differential mode signal SV1b has a positive polarity relative to the bias voltage VB2, which causes the virtual valve 112 to be closed.

[0071] At time T 22 The differential mode signal SV2a has a positive polarity relative to the bias voltage VB1, and the differential mode signal SV2b has a negative polarity relative to the bias voltage VB2, which causes the virtual valve 212 to be opened.

[0072] At time T 24 The differential mode signal SV1a has a positive polarity relative to the bias voltage VB1, and the differential mode signal SV1b has a negative polarity relative to the bias voltage VB2, which causes the virtual valve 112 to be opened.

[0073] At time T 24 The differential mode signal SV2a has a negative polarity relative to the bias voltage VB1, and the differential mode signal SV2b has a positive polarity relative to the bias voltage VB2, which causes the virtual valve 212 to be closed.

[0074] In other words, the virtual valve 112 or 212 is closed during a time period of a first reversal corresponding to the movement of the first lobe 101 or 201 and a second reversal corresponding to the movement of the second lobe 103 or 203.

[0075] Furthermore, differential mode signals SV1a and SV2a (which can be considered as anti-podal) are opposite in polarity to bias voltage VB1; differential mode signals SV1b and SV2b (which can be considered as anti-podal) are opposite in polarity to bias voltage VB2. Additionally, common mode signals SM1 and SM2 (which can be considered as anti-podal) are opposite in polarity to bias voltage VB3 (refer to the double-differential-SM scheme).

[0076] For details on asymmetric initial deflection, please refer to US application number 19 / 424,094. For the sake of brevity, it will not be repeated here.

[0077] Asymmetric initial deflection can be applied to Figure 7 The unit configuration is shown. For example, multiple first units 10 of sub-region rg11 of region 1 and multiple third units 30 of sub-region rg12 of region 1 all receive a first signal set (SM1, SV1a, SV1b); multiple second units 20 of sub-region rg21 of region 2 and multiple fourth units 40 of sub-region rg22 of region 2 all receive a second signal set (SM2, SV2a, SV2b). The (drive) signals SV1a, SV1b, SV2a, SV2b, SM1, and SM2 are as follows: Figure 14 As shown (refer to the dual differential mode - SM scheme).

[0078] Furthermore, the projections of openings 12a, 12b, 12c and 12d (or simply 12) are formed between subregions rg11 and rg21, between subregions rg11 and rg22, between subregions rg22 and rg12, and between subregions rg12 and rg21, respectively.

[0079] In summary, the key feature of this invention lies in the integration of asymmetric initial deflection and (dual) differential mode (SM). By deliberately pre-biasing or offsetting the balance position of the lobes, the system overcomes the limitations of traditional mechanical structures, enabling the common-mode and differential-mode frequencies to harmonize at a single resonance point. This quasi-static (asymmetric) offset thus achieves airflow volumetric velocities unattainable by symmetric topologies, confirming that the initial deviation is the key driving force behind unprecedented operational efficiency.

[0080] The foregoing outlines the features of several embodiments, enabling those skilled in the art to fully understand the various implementations of the invention. Those skilled in the art should recognize that the invention provides a basis for designing or modifying other processes and structures to achieve substantially the same functionality and / or results as the embodiments described above. Furthermore, such equivalent configurations do not depart from the spirit and scope of the invention, and various changes, substitutions, and modifications can be made without departing from that spirit and scope.

Claims

1. An airflow generating device, comprising: The first unit is located in the first area; as well as A second unit is set in a second region, and the first unit is set in a corresponding manner to the second unit; The first unit generates a first air pressure with a first polarity in the first region, and the second unit generates a second air pressure with a second polarity in the second region. The second polarity is opposite to the first polarity; Wherein, at least one of the first unit and the second unit includes a membrane structure, the membrane structure including a pair of lobes, the pair of lobes including a first lobe and a second lobe facing each other; The lobes have an initial deflection difference or present an average displacement difference between the first lobes and the second lobes. The flaps operate at an ultrasonic frequency, causing the airflow generating device to generate multiple air pulses at an ultrasonic pulse rate.

2. The airflow generating device of claim 1, wherein, The initial deflection difference or the average displacement difference is greater than the thickness of the membrane structure.

3. The airflow generating device of claim 1, wherein, The flaps undergo a differential motion to form a virtual valve or opening at an opening frequency.

4. The airflow generating device as described in claim 3, wherein The lobe pair is driven according to a differential mode frequency to perform the differential mode motion; The differential frequency is the ultrasonic pulse rate.

5. The airflow generating device of claim 3, wherein, The flaps undergo a common-mode motion to generate an ultrasonic air pressure change.

6. The airflow generating device as claimed in claim 5, wherein, The common-mode frequency corresponding to the common-mode motion is equal to the differential-mode frequency corresponding to the differential-mode motion.

7. The airflow generating device as claimed in claim 6, wherein, The common-mode frequency and the differential-mode frequency are close to a resonant frequency of the lobe pair.

8. The airflow generating device as claimed in claim 1, wherein, A virtual valve is closed for a period of time corresponding to the first reversal of the first lobe movement of the first lobe and the second reversal of the second lobe movement of the second lobe.

9. The airflow generating device as described in claim 1, in, The first lobe is driven by a first differential signal, and the second lobe is driven by a second differential signal to form a virtual valve; The first differential signal includes a first bias voltage, and the second differential signal includes a second bias voltage. The first bias voltage is different from the second bias voltage.

10. The airflow generating device as described in claim 9, in, The first differential signal has a first polarity relative to the first bias voltage, and the second differential signal has a second polarity relative to the second bias voltage; The first polarity is opposite to the second polarity.

11. The airflow generating device as claimed in claim 9, wherein, The first and second lobes are driven by a common-mode signal to perform a common-mode motion to generate pressure changes.

12. The airflow generating device as claimed in claim 11, wherein, A differential frequency corresponding to the first differential signal is equal to a common frequency corresponding to the common signal.

13. The airflow generating device as claimed in claim 11, further comprising: A first actuator is disposed on the first lobe; and A second actuator is disposed on the second lobe.

14. The airflow generating device as described in claim 13, in, The first actuator includes a first electrode and a second electrode, and the second actuator includes a third electrode and a fourth electrode; The first electrode receives the first differential signal, and the third electrode receives the second differential signal. The second electrode and the fourth electrode receive the common-mode signal.

15. The airflow generating device as claimed in claim 1, in, The first unit includes a first pair of lobes, and the second unit includes a second pair of lobes; The first lobe pair includes the first lobe and the second lobe, and the second lobe pair includes a third lobe and a fourth lobe.

16. The airflow generating device as claimed in claim 15, wherein, The first lobe is driven by a first differential signal, the second lobe is driven by a second differential signal, the third lobe is driven by a third differential signal, and the fourth lobe is driven by a fourth differential signal to form a first virtual valve and a second virtual valve.

17. The airflow generating device as claimed in claim 16, in, The first differential mode signal and the third differential mode signal include a first bias voltage; The second differential signal and the fourth differential signal include a second bias voltage; The first bias voltage is different from the second bias voltage.

18. The airflow generating device as claimed in claim 17, in, The first differential signal and the third differential signal are opposite to the first bias voltage; The second differential signal and the fourth differential signal are opposite to the second bias voltage.

19. The airflow generating device as claimed in claim 15, comprising: A first actuator is disposed on the first lobe; A second actuator is disposed on the second lobe; A third actuator is disposed on the third lobe; and A fourth actuator is disposed on the fourth lobe.

20. The airflow generating device as claimed in claim 19, in, The first actuator includes a first electrode for receiving a first differential signal; The second actuator includes a second electrode for receiving a second differential signal; The third actuator includes a third electrode for receiving a third differential signal; The fourth actuator includes a fourth electrode for receiving a fourth differential signal.

21. The airflow generating device as claimed in claim 20, in, The first actuator includes a fifth electrode, the second actuator includes a sixth electrode, the third actuator includes a seventh electrode, and the fourth actuator includes an eighth electrode. The fifth electrode and the sixth electrode receive a first common-mode signal; The seventh electrode and the eighth electrode receive a second common-mode signal.

22. The airflow generating device as claimed in claim 21, wherein, The first common-mode signal and the second common-mode signal are opposite to a third bias voltage.

23. The airflow generating device as claimed in claim 1, further comprising: Multiple first units are located in this first region; as well as Multiple second units are located in this second area.

24. The airflow generating device as claimed in claim 1, further comprising: Unit 3 and Unit 4; The first unit is located in a first sub-region of the first region; The second unit is located in a first sub-region of the second region; The third unit is located in a second sub-region of the first region; The fourth unit is located in a second sub-region of the second region; Wherein, the first sub-region of the first region is adjacent to the first sub-region of the second region in a first direction; Wherein, the first sub-region of the first region is adjacent to the second sub-region of the second region in a second direction.

25. The airflow generating device as claimed in claim 24, in, The first unit and the third unit are driven by a first differential signal, a second differential signal and a first common-mode signal; The second unit and the fourth unit receive a third differential mode signal, a fourth differential mode signal and a second common mode signal.

26. The airflow generating device as claimed in claim 25, in, The first differential mode signal and the third differential mode signal include a first bias voltage; The second differential signal and the fourth differential signal include a second bias voltage; The first bias voltage is different from the second bias voltage.

27. The airflow generating device as claimed in claim 26, in, The first differential signal and the third differential signal are opposite to the first bias voltage; The second differential signal and the fourth differential signal are opposite to the second bias voltage; The first common-mode signal and the second common-mode signal are opposite to a third bias voltage.

28. The airflow generating device as claimed in claim 24, further comprising: A cover structure is disposed above the first unit, the second unit, the third unit and the fourth unit.

29. The airflow generating device as claimed in claim 28, in, A first opening, a second opening, a third opening, and a fourth opening are formed in the cover structure; The first opening is formed between a first sub-region of the first region and a first sub-region of the second region; The second opening is formed between the first sub-region of the first region and the second sub-region of the second region; The third opening is formed between the second sub-region of the second region and a second sub-region of the first region; The fourth opening is formed between the second sub-region of the first region and the first sub-region of the second region.

30. The airflow generating device as claimed in claim 24, further comprising: Multiple first units are set in the first sub-region of the first region; Multiple second units are set in the first sub-region of the second region; Multiple third units are located in the second sub-region of the first region; as well as Multiple fourth units are located in the second sub-region of the second region.

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