Air quality sensing module and air pump in handheld device

Abstract

The invention discloses an air quality sensing module and an air pump in a handheld device. The air quality sensing module comprises a cavity, an air quality sensor and an air pump, the air quality sensing module is disposed or is to be disposed within the handheld device. The air pump generates an air flow toward or away from the cavity to cause the air quality sensor to perform an air quality sensing operation. The direction of airflow generated by an air pump within the handheld device is reversible.

Description

Technical Field

[0001] The present invention relates to an air quality sensing module and an air pump, and more particularly to an air quality sensing module and an air pump within a handheld device. Background Art

[0002] Air quality is generally taken for granted as playing a crucial role in our health and well-being. The air we breathe is a complex mixture of gases and particulate matter, and the presence of pollutants can have serious short-term and long-term health consequences.

[0003] Poor air quality is associated with a range of respiratory and cardiovascular problems, including asthma, bronchitis, lung cancer, heart disease, stroke, etc., where harmful pollutants (e.g., particulate matter (such as PM2.5 and PM10), ozone (O3), nitrogen dioxide (NO2), and sulfur dioxide (SO2)) can irritate the trachea, reduce lung function, and cause inflammation. Vulnerable groups such as children, the elderly, and people with pre-existing health conditions are particularly susceptible to the adverse effects of air pollution.

[0004] Therefore, an air quality sensor is necessary for such groups.

[0005] Unfortunately, existing air quality sensors are typically large and inconvenient for personal use, which limits their ability to provide real-time, close-range, or even breathing zone air quality data, which is crucial for personal health decisions.

[0006] For example, current gas / dust / particle sensors are typically applied in air purifiers or vacuum cleaners, and sufficient airflow is driven by a fan in these devices. Since fan modules (whether with or without blades) require a rotor to drive, gas / particle sensors are difficult to use at close range due to their size and noise problems.

[0007] On the other hand, a carbon monoxide (CO) sensor requires air diffusion and sufficient concentration to have sufficient accuracy and acceptable response. Generally, it takes more than 30 seconds to measure the air once and obtain data. Therefore, such a slow response is not good enough for real-time use. From another perspective, carbon monoxide sensors are usually placed in the kitchen or where fire may not burn completely (which means the sensor follows the machine). If the sensor can follow the person / user and issue a warning message when the person / user encounters an environment with a high (or relatively high) carbon monoxide concentration, it can make the person / user safer. Therefore, this means that close-range use is crucial.

[0008] Accordingly, there is an urgent need to improve the existing technology. Summary of the Invention

[0009] Therefore, the main object of the present invention is to provide an air quality sensing module within a handheld device, and the present invention also provides a related air pump.

[0010] An embodiment of the present invention discloses an air quality sensing module, which includes a cavity, an air quality sensor, and an air pump. The air quality sensing module is disposed or to be disposed within a handheld device. The air pump generates an air flow towards or away from the cavity to enable the air quality sensor to perform an air quality sensing operation. The direction of the air flow generated by the air pump within the handheld device is reversible.

[0011] An embodiment of the present invention discloses an air pump, which includes a first flap, a second flap, a first actuator, a second actuator, and an anchoring structure. The first flap and the second flap are opposite to each other in a top view when viewed along the top-down direction. The first actuator is disposed on the first flap, and the second actuator is disposed on the second flap. The first flap includes a first anchoring edge, which is anchored to the anchoring structure, and the first flap includes a plurality of non-anchored first free edges except for the first anchoring edge. The second flap includes a second anchoring edge, which is anchored to the anchoring structure, and the second flap includes a plurality of non-anchored second free edges except for the second anchoring edge.

[0012] After reading the detailed description of the embodiments with various drawings shown below, those of ordinary skill in the art should clearly understand the object of the present invention. Brief Description of the Drawings

[0013] Figure 1 A cross-sectional schematic diagram of an air pump according to an embodiment of the present invention is shown.

[0014] Figure 2 A cross-sectional schematic diagram of the common mode movement and differential mode movement of an air pump according to an embodiment of the present invention is shown.

[0015] Figure 3 A schematic diagram of an air pulse according to an embodiment of the present invention is shown.

[0016] Figure 4 A schematic diagram of the waveforms of a demodulation signal and a modulation signal according to an embodiment of the present invention is shown.

[0017] Figure 5 A cross-sectional schematic diagram of an air quality sensing module according to an embodiment of the present invention is shown.

[0018] Figure 6 The cross-sectional schematic diagram of an air quality sensing module according to an embodiment of the present invention is shown.

[0019] Figure 7 The cross-sectional schematic diagram of an air quality sensing module according to an embodiment of the present invention is shown.

[0020] Figure 8 The cross-sectional schematic diagram of an air quality sensing module according to an embodiment of the present invention is shown.

[0021] Figure 9 The cross-sectional schematic diagram of an air quality sensing module according to an embodiment of the present invention is shown.

[0022] Figure 10 The schematic diagrams of three designs of the air quality sensing module of the present invention are shown.

[0023] Figure 11 The schematic diagram of an air pump according to an embodiment of the present invention is shown.

[0024] Among them, the reference numerals are explained as follows:

[0025] 10: Membrane structure

[0026] 101, 103: Flap

[0027] 101n, 101n1: First free edge

[0028] 101r: First anchoring edge

[0029] 103n, 103n1: Second free edge

[0030] 103r: Second anchoring edge

[0031] 26A, 27A, 28A, 29A, 30A: Air quality sensing module

[0032] AFC, Q00, Q01: Air pump

[0033] AP: Air pulse

[0034] AP1: First air pulse

[0035] AP2: Second air pulse

[0036] AQ: Air quality sensor

[0037] AR: Anchoring structure

[0038] AT, AT1, AT2: Actuator

[0039] BS: Substrate

[0040] CB: Cavity

[0041] CV: Cover Structure

[0042] D1: First Direction

[0043] D2: Second Direction

[0044] DS1: First Design

[0045] DS2: Second Design

[0046] DS3: Third Design

[0047] DTT: Detection Target

[0048] fpulse: Ultrasonic Frequency

[0049] GP: Gap

[0050] H1, H2: Holes

[0051] HSS: Housing

[0052] OPV: Ventilation Opening

[0053] S1: Intermediate State

[0054] S2: Common-Mode Motion

[0055] S3: Differential-Mode Motion

[0056] SIN: Input Audio Signal

[0057] SL: Slit

[0058] SM: Modulation Drive Signal

[0059] SV: Demodulation Drive Signal

[0060] T1: First Time Period

[0061] T2: Second Time Period

[0062] TCY: Operation Cycle

[0063] X, Y, Z: Directions Detailed Implementation Manner

[0064] In the present invention, the technical features described in the embodiments can be mixed or combined in various ways as long as there is no conflict.

[0065] In the present invention, an air flow generating element is used to generate an air flow, and the air flow generating element can be applied in applications such as cooling, drying, dehumidifying, heat dissipation, ventilation, air sampling, air extraction, and / or exhaust by generating the air flow. In the present invention, the air flow generating element can be designed according to requirements, and the air flow generating element can be formed by any suitable method. Hereinafter, some embodiments of the air flow generating element will be described.

[0066] For example, the air flow generating element can be an air pump or an air flow generating wafer, and the air pump or the air flow generating wafer can be formed by a semiconductor process. For example, the air flow generating wafer can be a micro electromechanical system (MEMS) wafer and includes an MEMS structure, but is not limited thereto.

[0067] In the present invention, "air pump" and "air flow generating element / wafer" refer to the same element, and the names can be used interchangeably. In addition, the "air pump" and / or the "air flow generating element / wafer" can implement the concept of a fan-on-chip, that is, a small-sized element capable of generating an air flow (e.g., as small as the wafer size, where the wafer length / width can be less than 15 millimeters (mm)).

[0068] Due to the small size (e.g., as small as the wafer size, where the wafer length / width can be less than 15 millimeters), the air quality sensing module including the air flow generating element / wafer can be disposed in a handheld electronic device, thereby realizing real-time and close-range air quality sensing.

[0069] Please refer to Figure 1 and Figure 2 , Figure 1 The cross-sectional schematic diagram of an air pump according to an embodiment of the present invention is shown. Figure 2 The cross-sectional schematic diagram of the common-mode motion and differential-mode motion of an air pump according to an embodiment of the present invention is shown, where Figure 1 the air pump AFC shown is in the intermediate state S1. As shown in Figure 1 and Figure 2 , the air pump AFC is used to generate an air flow. In some embodiments, the air pump AFC can be used to generate a plurality of air pulses, and the air flow can be composed of the air pulses, where the air pump AFC can generate the air pulses at any suitable pulse rate. For example, the air pump AFC can generate the air pulses at an ultrasonic frequency (ultrasonic pulse rate) higher than the maximum audible frequency of humans (e.g., 16 kilohertz (kHz), 20 kHz, or 22 kHz), so that the user cannot hear the operation of the air pump AFC for generating the air flow and / or the air pulses, but is not limited thereto.

[0070] As shown in Figure 1As shown, the air pump AFC may include at least one anchoring structure AR and at least one membrane structure 10, and the membrane structure 10 is anchored on the anchoring structure AR, wherein the anchoring structure AR may be disposed outside the membrane structure 10. The membrane structure 10 and the anchoring structure AR may include any suitable materials. In some embodiments, the membrane structure 10 and the anchoring structure AR may each include silicon (e.g., single-crystalline silicon or polycrystalline silicon), silicon compounds (e.g., silicon carbide, silicon oxide), germanium, germanium compounds, gallium, gallium compounds (e.g., gallium nitride, gallium arsenide), other suitable materials, or combinations thereof, but not limited thereto. In some embodiments, the membrane structure 10 and the anchoring structure AR may have the same material.

[0071] During the operation of the air pump AFC, the membrane structure 10 may be actuated to move, and the anchoring structure AR may be stationary. In other words, during the operation of the air pump AFC, the anchoring structure AR may be a fixed end (or fixed edge) relative to the membrane structure 10. In some embodiments, the membrane structure 10 may be actuated to move upward and downward, but not limited thereto. In the present invention, the terms "move upward" and "move downward" mean that the membrane structure 10 substantially moves along the direction Z. Additionally, "upward" may refer to the direction Z (i.e., the +Z direction), and "downward" may refer to the direction opposite to the direction Z (i.e., the -Z direction). In other words, the actuation direction of the membrane structure 10 is parallel to the direction Z. In one embodiment, the direction Z may be the vertical direction and / or the top view direction.

[0072] As Figure 1 shown, the membrane structure 10 of the air pump AFC includes at least one slit SL, and the membrane structure 10 may be separated into a plurality of flaps (e.g., flaps 101, 103) through the slit SL. That is to say, the flaps may be separated from each other through the slit SL, and the slit SL may be the boundary of the flaps, wherein the number of flaps may be designed according to requirements. For example, as Figure 1 shown, the membrane structure 10 may be separated into a flap 101 and a flap 103 through the slit SL, and the two flaps 101, 103 may be disposed opposite to each other, and at least one slit SL may be between the two flaps 101, 103. It should be noted that the two flaps 101, 103 disposed opposite to each other may form a flap pair in the membrane structure 10.

[0073] In Figure 1 this, each of the flaps 101, 103 of the membrane structure 10 has at least one anchoring edge (or anchoring end) and at least one free edge (free end). The anchoring edge is anchored on the anchoring structure AR, and the free edge is not permanently anchored on any element in the air pump AFC, and the anchoring edges and free edges of each of the flaps 101, 103 may be designed according to requirements. For example (as Figure 1As shown, the slit SL can define a free edge of the flap 101 (e.g., the first free edge 101n1) and a free edge of the flap 103 (e.g., the second free edge 103n1). This free edge of the flap 101 (e.g., the first free edge 101n1) can be relative to the anchored edge of the flap 101, and this free edge of the flap 103 (e.g., the second free edge 103n1) can be relative to the anchored edge of the flap 103, but not limited thereto.

[0074] In the present invention, the number of slits SL included in the membrane structure 10 can be adjusted according to requirements, and the slits SL can be provided at any suitable position in the membrane structure 10 and have any suitable top view pattern. For example, the slit SL can be a straight slit, a curved slit, a combination of straight slits, a combination of curved slits, or a combination of straight slits and curved slits.

[0075] The air pump AFC can include an actuator AT for actuating the membrane structure 10 to generate an air flow and / or an air pulse, wherein the actuator AT can be provided at any suitable position, and the position of the actuator AT can be related to the actuation mode of the actuator AT. For example, in Figure 1 , the actuator AT can overlap the membrane structure 10 in the direction Z, but not limited thereto. For example, in Figure 1 , the actuator AT can be provided on the membrane structure 10, but not limited thereto. For example, in Figure 1 , the actuator AT can contact the membrane structure 10, but not limited thereto. As Figure 1 shown, the actuator AT can be divided into an actuator AT1 provided on the flap 101 and an actuator AT2 provided on the flap 103.

[0076] The actuator AT has a monotonic electromechanical conversion function for the movement of the membrane structure 10 in the direction Z. In some embodiments, the actuator AT may include a piezoelectric actuator, an electrostatic actuator, a nanoscopic - electrostatic - drive (NED) actuator, an electromagnetic actuator, or any other suitable actuator, but not limited thereto. For example, in one embodiment, the actuator AT may include a piezoelectric actuator, which may include, for example, two electrodes and a piezoelectric material layer disposed between the two electrodes (e.g., lead zirconate titanate (PZT)), where the piezoelectric material layer can actuate the membrane structure 10 according to the drive signal received by the electrodes (e.g., drive voltage and / or drive voltage difference between the two electrodes), but not limited thereto. For example, in another embodiment, the actuator AT may include an electromagnetic actuator (e.g., a planar coil), where the electromagnetic actuator can actuate the membrane structure 10 according to the drive signal received (e.g., drive current) and a magnetic field (i.e., the membrane structure 10 can be actuated by electromagnetic force), but not limited thereto. For example, in another embodiment, the actuator AT may include an electrostatic actuator (e.g., a conductive plate) or an NED actuator, where the electrostatic actuator or NED actuator can actuate the membrane structure 10 according to the drive signal received (e.g., drive voltage) and an electric field (i.e., the membrane structure 10 can be actuated by electrostatic force), but not limited thereto. Hereinafter, the actuator AT is exemplified as a piezoelectric actuator.

[0077] For example, if the air pump AFC is a MEMS wafer, the membrane structure 10, the anchoring structure AR, and the actuator AT may be MEMS structures in the MEMS wafer, but not limited thereto. Additionally, since the air pump AFC can generate an air flow and / or air pulses by actuating the membrane structure 10 with the actuator AT, the air pump AFC can be a bladeless fan, but not limited thereto.

[0078] In the present invention, the membrane structure 10 (flap pieces 101, 103) can be actuated / controlled by the actuator AT to move upward or downward, such that the ventilation opening OPV related to the slit SL is formed / opened or closed (i.e., the membrane structure 10 is used to form / open the ventilation opening OPV or close the ventilation opening OPV), wherein the ventilation opening OPV is formed between two opposite side walls of the slit SL (i.e., the ventilation opening OPV is formed between the two flap pieces 101, 103). In other words, the ventilation opening OPV is formed due to the slit SL. In the case of "ventilation opening OPV closed / sealed", it is difficult for air to pass through the space between two opposite side walls of the slit SL, which means that the flow resistance of the ventilation opening OPV is relatively large or greater than a threshold value. In the case of "ventilation opening OPV formed / opened", air can easily pass through the space between two opposite side walls of the slit SL, which means that the flow resistance of the ventilation opening OPV is relatively small or less than another threshold value.

[0079] In the present invention, the air pump AFC can generate an air flow and / or air pulses by any suitable air flow generation method. For example, Figure 1 Regarding Figure 2 the air flow generation method will be described below, and this air flow generation method can generate an air flow and / or air pulses by changing the state of the ventilation opening OPV and the air pressure on two opposite sides of the membrane structure 10.

[0080] As Figure 1 shown, in the intermediate state S1 of the air pump AFC, the membrane structure 10 (flap pair) can be actuated and maintained at a first position that is substantially horizontal (in cross-section) to temporarily close (or even temporarily seal) the ventilation opening OPV, such that it is difficult for air to pass through the space between two opposite side walls of the slit SL. In Figure 1 this case, two opposite side walls of the slit SL (i.e., the first free edge 101n1 of the flap piece 101 and the second free edge 103n1 of the flap piece 103) partially overlap or completely overlap with each other in the horizontal direction (such as the gap GP of the slit SL shown in Figure 1 ), so as to close the ventilation opening OPV and have a relatively large flow resistance. In one embodiment, the horizontal direction generally refers to the direction parallel to the horizontal plane, such as the direction X and the direction Y perpendicular to the direction Z.

[0081] In Figure 1In this case, since the size of the gap GP of the slit SL (or the width of the slit SL) should be small enough, due to the viscous forces / resistance along the walls of the air flow path (which can be referred to as the in-field boundary layer effect of fluid mechanics), the air flow through the gap GP (i.e., the narrow channel) can be highly damped. Therefore, in the intermediate state S1, the air flow through the gap GP is small enough and can be ignored. In other words, when the air pump AFC is in the intermediate state S1, the ventilation opening OPV is closed and even sealed. The size of the gap GP of the slit SL (or the width of the slit SL) can be designed according to requirements. For example, the size of the gap GP of the slit SL (or the width of the slit SL) can be less than or equal to 5 micrometers (μm), less than or equal to 3 micrometers, less than or equal to 2 micrometers, or be 1 to 2 micrometers, but not limited thereto. It should be noted that the size of the ventilation opening OPV in the intermediate state S1 can be the same as the size of the gap GP.

[0082] In Figure 2 this case, the membrane structure 10 (the pair of flaps) can be actuated to perform a common-mode motion S2, such that the two flaps 101, 103 are actuated in the same direction simultaneously. For example, the two flaps 101, 103 can be actuated simultaneously to move upward or downward along the direction Z. For example, at the end of the common-mode motion S2, the distance between the flap 101 and the first position is the same as the distance between the flap 103 and the first position.

[0083] As Figure 2 shown, when the membrane structure 10 (the pair of flaps) is actuated to perform a common-mode motion S2, the ventilation opening OPV can be temporarily closed (or even temporarily sealed), making it difficult for air to pass through the space between the two opposite sidewalls of the slit SL. In Figure 2 this case, the two opposite sidewalls of the slit SL (i.e., the first free edge 101n1 of the flap 101 and the second free edge 103n1 of the flap 103) partially overlap or completely overlap with each other in the horizontal direction, so as to close the ventilation opening OPV and have a large flow resistance.

[0084] When the membrane structure 10 (the pair of flaps) is actuated to perform a common-mode motion S2, due to the ventilation opening OPV being temporarily closed and having a large flow resistance, the air pressures on the two opposite sides of the membrane structure 10 will be different, resulting in a pressure difference. In other words, the membrane structure 10 (the pair of flaps) performs a common-mode motion S2 to form a pressure change.

[0085] In Figure 2In this case, the membrane structure 10 (a pair of flaps) can be actuated to perform a differential mode motion S3 such that the two flaps 101 and 103 are simultaneously actuated in opposite directions. For example, the flap 101 can be actuated to move downward and the flap 103 can be actuated to move upward (as Figure 2 shown), or the flap 101 can be actuated to move upward and the flap 103 can be actuated to move downward. For example, at the end of the differential mode motion S3, the distance between the flap 101 and the first position is the same as the distance between the flap 103 and the first position.

[0086] As Figure 2 shown, when the membrane structure 10 (a pair of flaps) is actuated to perform the differential mode motion S3, the ventilation opening OPV can be temporarily opened so that air can easily pass through the space between the two opposite side walls of the slit SL. In Figure 2 this case, the two opposite side walls of the slit SL (i.e., the first free edge 101n1 of the flap 101 and the second free edge 103n1 of the flap 103) do not overlap each other in the horizontal direction so that the ventilation opening OPV is opened with a small flow resistance.

[0087] When the membrane structure 10 (a pair of flaps) is actuated to perform the differential mode motion S3, if there is a pressure difference between the two opposite sides of the membrane structure 10, air will naturally flow through the ventilation opening OPV based on this pressure difference and the small flow resistance of the ventilation opening OPV, so that an air flow and / or an air pulse can be generated.

[0088] Accordingly, the air flow generation method of this embodiment can perform a common mode motion S2 and a differential mode motion S3 by actuating the membrane structure 10 (a pair of flaps) to generate an air flow and / or an air pulse. For example, a time period of the air flow generation method of this embodiment can include four steps, but is not limited thereto. The first step of the air flow generation method can actuate the membrane structure 10 (a pair of flaps) to perform the common mode motion S2 so that a pressure difference exists between the two opposite sides of the membrane structure 10. The second step of the air flow generation method can actuate the membrane structure 10 (a pair of flaps) to return to the intermediate state S1. The third step of the air flow generation method can actuate the membrane structure 10 (a pair of flaps) to perform the differential mode motion S3 so that air naturally flows through the ventilation opening OPV based on this pressure difference and the small flow resistance of the ventilation opening OPV, thereby generating an air flow and / or an air pulse. The fourth step of the air flow generation method can actuate the membrane structure 10 (a pair of flaps) to return to the intermediate state S1. By repeating the time period of the air flow generation method of this embodiment, air pulses can continuously form an air flow.

[0089] The frequency of the above time period can be designed according to the pulse rate of the air pulse, and the frequency of the time period can be synchronized with the pulse rate of the air pulse. In the present invention, one frequency / ratio being synchronized with another frequency / ratio generally means that this frequency / ratio is the other frequency / ratio multiplied by a rational number (i.e., N / M, where N and M represent integers). In some embodiments, the frequency of this time period can be the same as the pulse rate of the air pulse. In some embodiments, the membrane structure 10 (valve pair) performs a common-mode motion S2 to form an air pressure change at a frequency of pressure change synchronized with the frequency of this time period, and the membrane structure 10 (valve pair) performs a differential-mode motion S3 to form a ventilation opening OPV at an opening frequency synchronized with the frequency of this time period and the frequency of pressure change. For example, the frequency of this time period, the pulse rate of the air pulse, the frequency of pressure change, and the opening frequency can be the same as each other. For example, if the air pump AFC generates air pulses at an ultrasonic frequency, the frequency of pressure change and the opening frequency are synchronized with this ultrasonic frequency.

[0090] The flow direction of the air flow and the flow direction of the air pulse can be determined by the direction of the common-mode motion S2 performed by the membrane structure 10 (valve pair). When the membrane structure 10 (valve pair) is actuated to move upward (or downward) to perform only one type of common-mode motion S2 in the first step of a plurality of time periods, the types of air pressure differences in the first step of these time periods are the same as each other, thereby making the flow directions of the air pulses generated in these time periods (the third step) the same. Therefore, the air pump AFC can generate single-ended (SE) air pulses or quasi-single-ended air pulses. And the air pulses are asymmetric.

[0091] In the present invention, the waveform of the single-ended air pulse or the waveform of the quasi-single-ended air pulse can mean that the waveform is (substantially) unipolar with respect to a certain level. For example, the single-ended air pulse or the quasi-single-ended air pulse can mean that the waveform is (substantially) unipolar with respect to the ambient pressure (such as 1 ATM). In other words, the single-ended air pulse or the quasi-single-ended air pulse constitutes a net air movement or a net air flow in a single direction.

[0092] The air flow generation method of the present invention is not limited to the above content. In a time period of the air flow generation method, the number of steps and the order of the actuation motions of the membrane structure 10 (valve pair) can be designed according to requirements.

[0093] In another aspect, for any common-mode motion S2 of the flap pair, a pair of acoustic pressure waves is generated, one in the space on one side of the membrane structure 10 and the other in the space on the opposite side of the membrane structure 10, and these two acoustic pressure waves have the same amplitude magnitude but opposite polarities. Thus, when the ventilation opening OPV is opened, the air pressure difference between the two air masses near the ventilation opening OPV will cancel each other out. Accordingly, when the timing at which the differential-mode motion S3 reaches its peak (i.e., the timing at which the ventilation opening OPV reaches its maximum opening) aligns with the timing at which the acceleration of the common-mode motion S2 reaches its peak, it is expected that the acoustic pressure generated by the common-mode motion S2 should be suppressed or eliminated due to the opening of the ventilation opening OPV, resulting in the automatic cancellation between the two acoustic pressures on the two opposite sides of the membrane structure 10, where these two acoustic pressures have the same magnitude but opposite polarities. This means that when the ventilation opening OPV is opened, the air pump AFC will generate (near) net-zero air pressure. Therefore, when the opening period of the ventilation opening OPV overlaps with the period of one of the (two) polarities of the acceleration of the common-mode motion S2 of the flap pair, the air pump AFC will generate a single-ended air pulse or a quasi-single-ended air pulse.

[0094] In addition, by aligning the opening timing of the ventilation opening OPV with the timing of the acceleration of the common-mode motion S2 of the flap pair, the air pump AFC can generate asymmetric air pulses.

[0095] In some embodiments, the membrane structure 10 (flap pair) can be actuated to simultaneously perform the common-mode motion S2 and the differential-mode motion S3, but not limited thereto. In some embodiments, the membrane structure 10 can include other parts to enable the common-mode motion S2 and the differential-mode motion S3 to be simultaneously performed by the membrane structure 10, but not limited thereto.

[0096] In the present invention, the actuator AT can receive any suitable signal to actuate the membrane structure 10. In some embodiments, the membrane structure 10 is actuated by modulating the drive signal SM to perform the common-mode motion S2 to form a pressure change, and the membrane structure 10 is actuated by demodulating the drive signal SV to perform the differential-mode motion S3 to form the ventilation opening OPV, where both the modulation drive signal SM and the demodulation drive signal SV are related to the output amplitude of the air pulse. It should be noted that the demodulation drive signal SV can be presented as +SV or –SV in Figure 4 to represent opposite signals.

[0097] In addition, the modulation frequency of the modulation drive signal SM and the demodulation frequency of the demodulation drive signal SV can be related to the pulse rate of the air pulse. For example, the modulation frequency and the demodulation frequency can be synchronized with the pulse rate of the air pulse, such that the modulation frequency and the demodulation frequency can be synchronized with the pressure change frequency of the pressure change, the opening frequency of the ventilation opening OPV, and the frequency of the aforementioned period, but not limited thereto.

[0098] In some embodiments, the actuator AT may receive the modulation drive signal SM and the demodulation drive signal SV at different times, but is not limited thereto. In some embodiments, the actuator AT may include a plurality of sub-parts in a top view, one sub-part may receive the modulation drive signal SM, and another sub-part may receive the demodulation drive signal SV, but is not limited thereto. In some embodiments, the actuator AT may include a first electrode and a second electrode, the first electrode may receive the modulation drive signal SM, and the second electrode receives the demodulation drive signal SV, but is not limited thereto.

[0099] In addition, by controlling the modulation drive signal SM and / or the demodulation drive signal SV, the flow direction of the air flow (air pulse) generated by the air pump AFC can be reversible. For detailed content, reference can be made to U.S. Patent Application No. 18 / 624,105 filed by the same applicant. For the sake of brevity, it will not be described herein.

[0100] For the detailed content (such as structure, drive signal and movement) of the air flow generating MEMS device (i.e., air pump AFC) manufactured by semiconductor process and its design / operation principle, reference can be made to U.S. Patent No. 11,943,585, U.S. Patent Application No. 18 / 321,757 and U.S. Patent Application No. 18 / 624,105 filed by the same applicant. Therefore, these U.S. patents and U.S. patent applications are incorporated herein by reference.

[0101] As mentioned above, the air pump AFC of the present invention can generate asymmetric air pulses and can be applied to applications such as cooling, drying, dehumidifying, heat dissipation, ventilation, air sampling, air extraction and / or exhaust, etc., wherein (asymmetric) air pulses are generated to form a continuous unidirectional net air movement.

[0102] In addition, the air pump AFC of the present invention for air flow applications can be disposed in an air quality sensing device, wherein the air quality sensing device is used to sense the concentration of, for example, specific particles (such as particulate matter (PM), like PM2.5 or PM10) or compounds (such as ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2) and carbon monoxide (CO), etc.) in the air. Therefore, the size of the air quality sensing device can be greatly reduced.

[0103] For example, Figure 3 The schematic diagram of the air pulse AP of an embodiment of the present invention is shown. The air pulse can be generated by the air pump AFC of the present invention, and the air pump AFC includes a membrane structure 10. As mentioned above, the membrane structure 10 of the air pump AFC can be actuated to perform movement, and air pulses AP are generated at an ultrasonic frequency f pulse (such as 96 kHz or 192 kHz), and the ultrasonic frequency f pulseMay be, for example, the ultrasonic carrier frequency f UC The operating period T CY The reciprocal of. In this case, the ultrasonic frequency f pulse May be the ultrasonic carrier frequency f UC . The air pulse AP can generate a net air flow in a single direction.

[0104] In one embodiment, the first air pulse AP1 can generate a first net air flow that continuously moves in a single direction (e.g., the first direction D1). For Figure 3 example, during the first time period T1, the air pulses AP all move in the first direction D1. When the first time period T1 is at least equal to or longer than the reciprocal of the minimum audible frequency of humans, the first net air flow generated by the first air pulse AP1 can be considered to continuously move in a single direction (e.g., the first direction D1). For example, in the case where the minimum audible frequency of humans is 10 Hertz (Hz), when the first time period T1 is at least equal to or longer than 0.1 second, the first net air flow can be considered to continuously move in a single direction (e.g., the first direction D1). It should be noted that the first amplitudes corresponding to the first air pulse AP1 moving in the first direction D1 may be the same or different from each other.

[0105] On the other hand, the air pump AFC can generate a second air pulse AP2, and the second air pulse AP2 can generate a second net air flow that continuously moves in the second direction D2, where the second direction D2 is opposite to the first direction D1. In one embodiment, when the air pump AFC generates a significant air flow or air movement, and the air pulses switching between the first direction D1 and the second direction D2 are indistinguishable, the first net air flow can be considered to continuously move in the first direction D1 during the first time period T1, and / or the second net air flow can be considered to continuously move in the second direction D2 during the second time period T2.

[0106] The membrane structure can be actuated by the demodulation drive signal SV and the modulation drive signal SM. It should be noted that in the present invention, the modulation drive signal SM can also be called the modulation signal, which is also a kind of drive signal. Similarly, the demodulation drive signal SV can be called the demodulation signal, which is also a kind of drive signal.

[0107] Figure 4 Shown is a schematic diagram of the waveforms of the demodulation signal and the modulation signal according to an embodiment of the present invention, where the transitions between high / low voltages are ignored. As Figure 4 shown, the modulation / drive signal (e.g., the modulation drive signal SM) can be generated according to an input signal (e.g., the input audio signal S IN ), and the input signal can be or include a DC offset (or non-zero DC offset) (e.g., a DC voltage or a non-zero DC voltage). In other words, the input signal can be only a DC signal, but not limited thereto.

[0108] In one embodiment, the DC offset may be related to the direction of the net air flow. For example, during a first time period T1, in response to the DC offset being positive, the air pulse may generate a first net air flow continuously directed towards a first direction D1. On the other hand, during a second time period T2, in response to the DC offset being negative, the air pulse generated by the air pump AFC may generate a second net air flow continuously directed towards a second direction D2, and the second direction D2 is opposite to the first direction D1. In this regard, the air pump AFC or the air flow generating device of the present invention can be regarded as a voltage-air flow converter, which can convert voltage into air flow.

[0109] In addition to the polarity of the DC offset, the direction of the net air flow can also be determined or controlled by the phase between the modulation signal (modulation drive signal SM) and the demodulation signal (demodulation drive signal SV). For example, in Figure 4 the transition of the demodulation signal (demodulation drive signal SV) aligns with the period when the modulation signal (modulation drive signal SM) is at a low level. In this case, the air pump AFC can generate an air flow, for example, towards a third direction. When the demodulation signal (demodulation drive signal SV) or its phase is shifted such that the transition of the demodulation signal (demodulation drive signal SV) aligns with the period when the modulation signal (modulation drive signal SM) is at a high level, the air pump AFC can generate an air flow towards a fourth direction, and the fourth direction is opposite to the third direction. In short, the direction of the net air flow generated by the air pump AFC can be determined or controlled by the phase (or phase difference) between the modulation signal (modulation drive signal SM) and the demodulation signal (demodulation drive signal SV).

[0110] The intensity or volume of the net air flow can be a function of the DC offset or related to the magnitude of the DC offset. By maintaining the air flow direction (whether it is the first direction or the second direction), the air pump AFC can dissipate heat, dehumidify, ventilate, air sample, pump air, exhaust air, and / or promote air circulation. In this case, the air pump AFC can be regarded as a fanless blower or a bladeless fan. That is to say, the air pump AFC can also be regarded as a fanless blower, especially when the drive signal or modulation drive signal applied to it is based on an input signal, and this input signal contains a non-zero DC offset / component. In the present invention, the terms "air pulse generating device", "air flow generating device", "air pump", and "exhaust fan" can be used interchangeably.

[0111] Due to the small size of the air pump based on the present invention, the air quality sensing module including the air pump can be disposed (integrated) within a handheld device. For example, the handheld device can be a (smart) phone, a (smart) watch, or other suitable portable handheld devices.

[0112] Please refer to Figure 5 Figure 5The following is a cross-sectional schematic diagram of an air quality sensing module according to an embodiment of the present invention. As Figure 5 shown, the air quality sensing module 26A includes a housing HSS, and a cavity CB is present within the housing HSS. The housing HSS can be an integral structure or can be formed by multiple sub-structures.

[0113] As Figure 5 shown, the air quality sensing module 26A includes an air quality sensor AQ, where the air quality sensor AQ is disposed within the housing HSS, and the air quality sensor AQ performs an air quality sensing operation to sense at least one detection target DTT, thereby sensing the air quality in the cavity CB. For example, the air quality sensor AQ can sense the concentration of the detection target DTT, and the detection target DTT can include specific particles in the air (such as, PM 2.5 or PM 10) or compounds (such as, ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide, etc.), but is not limited thereto.

[0114] As Figure 5 shown, the air quality sensing module 26A includes an air pump Q00, which is any one of the aforementioned air pumps AFC, where the air pump Q00 generates an air flow towards or away from the cavity CB to enable the air quality sensor AQ to perform an air quality sensing operation. For example, the air pump Q00 can be disposed at a hole H1 corresponding to the housing HSS, such that the air pump Q00 can generate an air flow from the surrounding environment towards the cavity CB or generate an air flow from the cavity CB towards the surrounding environment.

[0115] The direction of the air flow can be designed according to the type of the air quality sensing module 26A or other requirements. For example (as Figure 5 shown), the air pump Q00 generates a first air flow from the surrounding environment towards the cavity CB, such that the air quality sensor AQ senses the air quality of the surrounding environment during a first period; the air pump Q00 generates a second air flow from the cavity CB towards the surrounding environment to update the cavity CB during a second period (i.e., the direction of the air flow generated by the air pump Q00 of the present invention is reversible). In other words, the air pump Q00 pumps air into and out of the cavity CB at different times. It should be noted that the pressure in the cavity CB during the first period can be greater than the pressure in the cavity CB during the second period. For example, the pressure in the cavity CB during the first period can be greater than the pressure of the surrounding environment, but is not limited thereto.

[0116] Continuing from the foregoing, the direction of the air flow can be reversed by changing the phase (or phase difference) between the modulation signal (modulation drive signal SM) and the demodulation signal (demodulation drive signal SV), or by changing the DC offset embedded in the input signal (such as, the input audio signal S IN ).

[0117] In addition, the intensity of the airflow generated by the air pump Q00 of the present invention is adjustable. For example, the intensity of the airflow can be adjusted by adjusting the amplitude of the modulation signal (modulation drive signal SM) or the amplitude of the demodulation signal (demodulation drive signal SV). For example, the intensity of the airflow can also be adjusted by adjusting the frequency of the modulation signal (modulation drive signal SM) or the frequency of the demodulation signal (demodulation drive signal SV), which utilizes the resonance gain of the membrane structure 10 (such as, the flap pair), especially when the frequency of the modulation signal (modulation drive signal SM) or the frequency of the demodulation signal (demodulation drive signal SV) is close to the resonance frequency of the membrane structure 10.

[0118] Please refer to Figure 6 , Figure 6 The cross-sectional schematic diagram of the air quality sensing module according to an embodiment of the present invention is shown. As Figure 6 shown, another type of air quality sensing module 27A is provided. In Figure 6 , the air quality sensing module 27A may include another air pump Q01, which is disposed in or corresponding to the hole H2 of the housing HSS, wherein the structure of the air pump Q01 may be the same as or different from the structure of the air pump Q00. In the present invention, the directions of the airflow generated by the air pumps Q00 and Q01 can be designed according to requirements. In one example, in the first time period, the air pump Q00 may generate a first airflow from the surrounding environment towards the cavity CB, and the air pump Q01 may generate a third airflow from the surrounding environment towards the cavity CB; in the second time period, the air pump Q00 may generate a second airflow from the cavity CB towards the surrounding environment, and the air pump Q01 may generate a fourth airflow from the cavity CB towards the surrounding environment, but not limited thereto. It should be noted that the pressure in the cavity CB in the first time period may be greater than the pressure in the cavity CB in the second time period.

[0119] In another example, the air pump Q00 may generate an airflow from the surrounding environment towards the cavity CB, and the air pump Q01 may simultaneously generate another airflow from the cavity CB towards the surrounding environment, or, the air pump Q00 may generate an airflow from the cavity CB towards the surrounding environment, and the air pump Q01 may simultaneously generate another airflow from the surrounding environment towards the cavity CB (that is, the directions of the airflow generated by the air pumps Q00 and Q01 of the present invention are reversible), so that the cavity CB can be an air passage, but not limited thereto.

[0120] In addition, the air pump of the present invention can be integrated into the air quality sensing module at the package level, and an embodiment of the air quality sensing module at the package level is illustrated in Figures 7 to 9 . It should be noted that the air quality sensing module at the package level can be formed by a semiconductor process (the semiconductor process includes a packaging process).

[0121] In Figure 7In [description], the housing HSS of the air quality sensing module 28A may include a substrate BS, on which an air pump Q00 and an air quality sensor AQ may be disposed. The substrate BS may be a rigid substrate or a flexible substrate, and the substrate BS may include glass, plastic, quartz, sapphire, metal, polymer (e.g., polyimide (PI), polyethylene terephthalate (PET)), any suitable material, or a combination thereof. In one example, the substrate may be a circuit board including a laminate (e.g., a copper clad laminate (CCL)), a land grid array board (LGA board), or any other suitable board including a conductive material, but not limited thereto. In Figure 7 [description], the normal direction of the substrate BS may be parallel to the direction Z.

[0122] In Figure 7 [description], the housing HSS of the air quality sensing module 28A may include a covering structure CV for covering and protecting the air pump Q00 and the air quality sensor AQ. In Figure 7 [description], the air pump Q00 and the air quality sensor AQ may be disposed between the substrate BS and the covering structure CV. For example, the covering structure CV may include glass, plastic, quartz, sapphire, metal, polymer, any suitable material, or a combination thereof. For example, the covering structure CV may be an integral structure or may be formed by a plurality of sub-structures (e.g., a plurality of substrates).

[0123] In Figure 7 [description], the substrate BS may have a hole H1, and the air pump Q00 corresponds to the hole H1, so that the air pump Q00 can generate an air flow from the surrounding environment toward the cavity CB or from the cavity CB toward the surrounding environment. For example, in Figure 7 [description], the air pump Q00 generates a first air flow from the surrounding environment toward the cavity CB, so that the air quality sensor AQ senses the air quality of the surrounding environment in the first period; the air pump Q00 generates a second air flow from the cavity CB toward the surrounding environment to update the cavity CB in the second period. It should be noted that the pressure in the cavity CB in the first period may be greater than the pressure in the cavity CB in the second period.

[0124] Compared with Figure 7 the air quality sensing module 28A shown in Figure 8The covering structure CV of the air quality sensing module 29A shown may also have another hole H2, such that the air flow generated by the air pump Q00 can flow between the two holes H1 and H2, and the cavity CB can be an air channel. Since the direction of the air flow generated by the air pump Q00 of the present invention is reversible, therefore, the air pump Q00 can generate an air flow from the surrounding environment towards the cavity CB in one period, and generate an air flow from the cavity CB towards the surrounding environment in another period, but not limited thereto.

[0125] Compared with Figure 7 the air quality sensing module 28A shown, Figure 9 the air quality sensing module 30A shown may have another air pump Q01, and the substrate BS may also have a hole H2. In one example ( Figure 9 ), in the first period, the air pump Q00 can generate a first air flow from the surrounding environment towards the cavity CB, and the air pump Q01 can generate a third air flow from the surrounding environment towards the cavity CB; in the second period, the air pump Q00 can generate a second air flow from the cavity CB towards the surrounding environment, and the air pump Q01 can generate a fourth air flow from the cavity CB towards the surrounding environment, such that the pressure of the cavity CB in the first period can be greater than the pressure of the cavity CB in the second period, but not limited thereto.

[0126] In another example ( Figure 9 ), the air pump Q00 can generate an air flow from the surrounding environment towards the cavity CB, and the air pump Q01 can simultaneously generate another air flow from the cavity CB towards the surrounding environment, or, the air pump Q00 can generate an air flow from the cavity CB towards the surrounding environment, and the air pump Q01 can simultaneously generate another air flow from the surrounding environment towards the cavity CB (i.e., the directions of the air flows generated by the air pumps Q00 and Q01 of the present invention are reversible), such that the cavity CB can be an air channel, but not limited thereto.

[0127] Figure 10 Three designs of the air quality sensing module are illustrated. In the first design DS1, the air pump Q00 can respectively draw air into the cavity CB and draw air out of the cavity CB through the hole H1 at different times, where Figure 5 the air quality sensing module 26A shown and Figure 7 the air quality sensing module 28A shown belong to the first design DS1. In the second design DS2, the air pump Q00 can draw air into the cavity CB through the hole H1 and the air can flow out of the cavity CB through the hole H2, or, the air pump Q00 can draw air out of the cavity CB through the hole H1 and the air can flow into the cavity CB through the hole H2, where Figure 8The illustrated air quality sensing module 29A belongs to the second design DS2. In the third design DS3, the air pumps Q00, Q01 can simultaneously draw air into the cavity CB or simultaneously draw air out of the cavity CB through the holes H1, H2, or the air pump Q00 can draw air into the cavity CB through the hole H1 and the air pump Q01 can simultaneously draw air out of the cavity CB through the hole H2, where Figure 6 the illustrated air quality sensing module 27A and Figure 9 the illustrated air quality sensing module 30A belongs to the third design DS3.

[0128] Please refer to Figure 11 , Figure 11 the schematic diagram of the air pump according to an embodiment of the present invention is shown. It should be noted that Figure 11 the illustrated air pump Q00 can be an example used in the air quality sensing module, and the air pump Q00 can be, for example, a MEMS wafer. As Figure 11 shown, the two flaps 101, 103 of the air pump Q00 are opposite to each other in the top view when viewed along the top view direction (i.e., the direction Z), and the actuators AT1, AT2 are respectively disposed on the flaps 101, 103. It should be noted that the two flaps 101, 103 form a flap pair.

[0129] In Figure 11 , the flap 101 includes a first anchoring edge 101r, the first anchoring edge 101r is anchored on the anchoring structure AR, and the flap 101 includes a non-anchored first free edge 101n other than the first anchoring edge 101r. Similarly, the flap 103 includes a second anchoring edge 103r, the second anchoring edge 103r is anchored on the anchoring structure AR, and the flap 103 includes a non-anchored second free edge 103n other than the second anchoring edge 103r. In other words, each of the flaps 101, 103 has only one anchoring edge, and the other edges are free edges.

[0130] In Figure 11 , a slit SL is formed between the two flaps 101, 103, so that the two flaps 101, 103 are separated by the slit SL, and a first free edge 101n1 of the flap 101 and a second free edge 103n1 of the flap 103 are defined by the slit SL (the first free edge 101n1 and the second free edge 103n1 are two opposite side walls of the slit SL). It should be noted that the ventilation opening OPV formed between the two flaps 101, 103 is formed because of the slit SL.

[0131] Simulations were conducted to verify the technical effects of an air pump or an air flow generating element / wafers, where the air pump or the air flow generating element / wafers are used to generate an air flow directed towards a closed cavity. The simulation results show that the air pressure within the cavity can be increased to a steady state within less than 0.5 milliseconds (ms). This means that, in terms of the measurement results, the time for the air quality sensing module to obtain air quality data does not need to be too long. Therefore, in addition to sensing the air quality in the vicinity, real-time air quality sensing can also be achieved.

[0132] In summary, by applying a small-sized air pump or an air flow generating wafer in the air quality sensing module, the air quality sensing module can be integrated into a handheld electronic device (e.g., a smartphone or a smartwatch). Therefore, revolutionary real-time near-field air quality sensing can be achieved.

[0133] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made in accordance with the claims of the present invention shall fall within the scope of the present invention.

Claims

1. An air quality sensing module, comprising: a cavity; an air quality sensor; and an air pump; wherein the air quality sensing module is disposed or to be disposed within a handheld device; wherein the air pump generates an air flow towards or away from the cavity to enable the air quality sensor to perform an air quality sensing operation; wherein a direction of the air flow generated by the air pump within the handheld device is reversible.

2. The air quality sensing module according to claim 1, wherein the air pump generates a first air flow from a surrounding environment towards the cavity, such that the air quality sensor senses the air quality of the surrounding environment during a first period; wherein the air pump generates a second air flow from the cavity towards the surrounding environment to update the cavity during a second period.

3. The air quality sensing module according to claim 1, wherein the air pump includes a membrane structure configured to be actuated to generate a plurality of air pulses at an ultrasonic frequency; wherein the plurality of air pulses generate a net air flow in a single direction.

4. The air quality sensing module according to claim 1, wherein the air pump includes a membrane structure; wherein the membrane structure includes a pair of flaps, the pair of flaps including a first flap and a second flap, the first flap and the second flap being disposed opposite to each other; wherein the pair of flaps is actuated to perform a movement to form an opening in synchronization with an opening frequency of an ultrasonic frequency.

5. The air quality sensing module according to claim 1, wherein the air pump includes a membrane structure; wherein the membrane structure is actuated by a drive signal; wherein the drive signal is generated according to an input signal, the input signal being a non-zero DC voltage or including a non-zero DC voltage.

6. The air quality sensing module according to claim 1, wherein the air pump includes a membrane structure; wherein the membrane structure is actuated by a modulation signal to perform a common mode movement; wherein the modulation signal is generated according to an input signal, the input signal being a non-zero DC voltage or including a non-zero DC voltage.

7. The air quality sensing module according to claim 1, wherein the air pump includes a membrane structure; wherein the membrane structure is actuated by a demodulation signal to perform a differential mode movement to form an opening in synchronization with an opening frequency of an ultrasonic frequency.

8. The air quality sensing module according to claim 1, wherein the air pump includes a membrane structure; wherein the membrane structure is actuated by a modulation signal to perform a common mode movement; wherein the membrane structure is actuated by a demodulation signal to perform a differential mode movement to form an opening; wherein a direction of the air flow generated by the air pump is controlled according to a phase between the modulation signal and the demodulation signal.

9. The air quality sensing module according to claim 1, wherein an intensity of the air flow generated by the air pump within the handheld device is adjustable.

10. The air quality sensing module according to claim 9, wherein the air pump includes a membrane structure; wherein the membrane structure is actuated by a modulation signal to perform a common-mode movement; wherein the membrane structure is actuated by a demodulation signal to perform a differential-mode movement to form an opening; wherein the intensity of the airflow is adjusted by adjusting the amplitude of the modulation signal, the amplitude of the demodulation signal, the frequency of the modulation signal, or the frequency of the demodulation signal.

11. The air quality sensing module according to claim 1, further comprising another air pump; wherein in a first period, the air pump generates a first airflow from a surrounding environment toward the cavity, and the another air pump generates a third airflow from the surrounding environment toward the cavity; wherein in a second period, the air pump generates a second airflow from the cavity toward the surrounding environment, and the another air pump generates a fourth airflow from the cavity toward the surrounding environment.

12. The air quality sensing module according to claim 1, further comprising another air pump, wherein the air pump generates the airflow from a surrounding environment toward the cavity, and the another air pump simultaneously generates another airflow from the cavity toward the surrounding environment.

13. The air quality sensing module according to claim 1, wherein the air pump is a microelectromechanical system chip.

14. An air pump, comprising: a first flap and a second flap, wherein the first flap and the second flap are opposite to each other in a top view when viewed along a top-down direction; a first actuator disposed on the first flap; a second actuator disposed on the second flap; and an anchoring structure; wherein the first flap includes a first anchoring edge that is anchored to the anchoring structure, and the first flap includes a plurality of non-anchored first free edges other than the first anchoring edge; wherein the second flap includes a second anchoring edge that is anchored to the anchoring structure, and the second flap includes a plurality of non-anchored second free edges other than the second anchoring edge.

15. The air pump according to claim 14, wherein a slit is formed between the first flap and the second flap; wherein one of the first free edges of the first flap and one of the second free edges of the second flap are defined by the slit.

16. The air pump according to claim 14, wherein the first flap and the second flap are actuated to perform a differential-mode movement to form an opening; wherein the opening is formed because of a slit.

17. The air pump according to claim 14, wherein the first flap and the second flap perform a common-mode movement to form a pressure change, and the first flap and the second flap perform a differential-mode movement to form an opening.

18. The air pump according to claim 17, wherein the first flap and the second flap perform the common-mode movement to form the pressure change at a frequency, and the first flap and the second flap perform the differential-mode movement to form the opening at an opening frequency synchronized with the frequency.

19. The air pump according to claim 14, wherein the first flap and the second flap are actuated to generate a plurality of air pulses, and the air pulses are asymmetric.

Images