A sensing device

Abstract

An embodiment of the present specification provides a sensing device, comprising: a shell having a housing chamber inside; a transducer unit including a vibration pickup structure for picking up the vibration of the shell and generating an electrical signal, wherein the transducer unit is separated in the housing chamber to form a front chamber and a rear chamber located on opposite sides of the vibration pickup structure, wherein at least one of the front chamber or the rear chamber is filled with liquid, and the liquid is in contact with the vibration pickup structure; and one or more pipe structures, each of which is configured to connect the housing chamber with the outside of the shell, and the liquid is at least partially located in the one or more pipe structures. The liquid and the one or more pipe structures in the present specification can enable the sensing device to have one or more additional resonance peaks and resonance valleys, and the resonance frequencies corresponding to the one or more additional resonance peaks and resonance valleys are different from the resonance frequencies corresponding to the transducer unit, so that the sensing device can be applied to different application scenarios, thereby improving the applicability of the sensing device.

Description

[0001] Priority information

[0002] This application claims priority to Chinese application No. 202110445739.3 filed on April 23, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This specification relates to the field of sensors, and in particular to a sensor device. Background Art

[0004] A sensing device is a device that receives an external vibration signal and converts the external vibration signal into an electrical signal through a transducer unit. The vibration pickup effect of the sensing device often depends on the response capability of the transducer unit to the vibration signal. Although the transducer unit can provide a natural resonant frequency that is closely related to its physical properties such as structure and material, the natural resonant frequency is often not within the ideal frequency range, thus limiting the application of the sensing device in different application scenarios. For example, in some application scenarios, the sensing device may be required to provide a higher response capability to vibration signals in a certain frequency range or certain frequency ranges, or to provide different response capabilities to vibration signals of different frequencies, but the natural resonant frequency of the transducer unit is difficult to meet these requirements. Summary of the Invention

[0005] An embodiment of the present specification provides a sensing device, comprising: a shell having an accommodating cavity therein; a transducer unit comprising a vibration pickup structure for picking up vibrations of the shell to generate an electrical signal, the transducer unit being separated within the accommodating cavity to form a front cavity and a rear cavity located on opposite sides of the vibration pickup structure, wherein at least one cavity in the front cavity or the rear cavity is filled with liquid, and the liquid is in contact with the vibration pickup structure; and one or more pipe structures, each pipe structure being configured to connect the accommodating cavity with the outside of the shell, and the liquid being at least partially located in the one or more pipe structures.

[0006] The sensing device provided in this specification has the following beneficial effects:

[0007] (1) The vibration pickup structure has a first resonant frequency in response to the vibration of the shell. The liquid in the fluid area corresponding to the pipeline structure and the outside of the shell connected to the pipeline structure have additional resonant peaks and resonant valleys. The resonant frequencies corresponding to the resonant peaks and resonant valleys are different from the first resonant frequency, so that the sensor device can have a good frequency response in different frequency bands, so that the sensor device can be suitable for different application scenarios, thereby improving the applicability of the sensor device; (2) Multiple pipeline structures correspond to multiple resonant systems, and the multiple resonant systems can provide the sensor with multiple additional resonant peaks and resonant valleys. At least one of the resonant frequencies corresponding to the multiple resonant peaks and resonant valleys is less than the first resonant frequency, which can greatly improve the response of the sensor device in the lower frequency band; (3) By setting different pipeline structures, the difference between the multiple resonant peaks and resonant valleys can be large, that is, the Q value is large. In this way, when the sensor device collects vibration signals, it will show different sensitivities to vibration signals of different frequency components. The generated electrical signal will appear as a fusion of multiple "sub-band" signals. In the back-end circuit or algorithm, only a low-order filter can be used to intercept the molecular band signal with a steeper boundary. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a schematic diagram of an exemplary sensing device according to some embodiments of the present specification;

[0009] Figure 2 is a schematic structural diagram of an exemplary microphone according to some embodiments of this specification;

[0010] Figure 3 is a schematic diagram of an exemplary equivalent vibration model of a transducer unit according to some embodiments of this specification;

[0011] Figure 4 is a schematic diagram of a displacement resonance curve of an exemplary sensing device according to some embodiments of this specification;

[0012] Figure 5 is a mechanical equivalent schematic diagram of an exemplary sensing device according to some embodiments of this specification;

[0013] Figure 6 is a schematic diagram of a sensing device filled with liquid according to some embodiments of this specification;

[0014] Figure 7 is a mechanical equivalent schematic diagram of an exemplary sensing device according to some embodiments of this specification;

[0015] Figure 8 is a schematic diagram of a sensing device filled with liquid and bubbles according to some embodiments of this specification;

[0016] Figure 9 is an exemplary frequency response curve of the sensing device 500 or 700 according to some embodiments of this specification;

[0017] Figure 10 is an exemplary frequency response curve of the sensing device 500 or 700 according to some embodiments of this specification;

[0018] Figure 11 is a schematic diagram of a sensing device to be filled with liquid according to some embodiments of this specification;

[0019] Figure 12 is a schematic diagram of an exemplary liquid-filled sensing device according to some embodiments of the present specification;

[0020] Figure 13 is a frequency response curve of the sensing device before and after being partially filled with liquid according to some embodiments of the present application;

[0021] Figure 14 This is a frequency response curve of a sensor device with a small-sized accommodating cavity before and after being filled with liquid according to some embodiments of this specification;

[0022] Figure 15 Frequency response curves of a sensor device with a large-sized accommodating cavity shown in some embodiments of this specification when the cavity is not filled with liquid, partially filled with liquid, or when an oil film exists in the accommodating cavity;

[0023] Figure 16 is a schematic diagram of a sensing device filled with liquid and bubbles according to some embodiments of this specification;

[0024] Figure 17 is a frequency response curve of a sensing device containing bubbles of different sizes in a liquid filled in a chamber according to some embodiments of this specification;

[0025] Figure 18A 、 Figure 18B 、 Figure 18C as well as Figure 18D is a schematic diagram of a sensing device for bubbles in a filling liquid at different positions according to some embodiments of this specification;

[0026] Figure 19 is a frequency response curve of bubbles in a filling liquid at different positions in the accommodating cavity of a sensor device according to some embodiments of this specification;

[0027] Figure 20 is a frequency response curve before and after the sensor device is filled with liquid according to some embodiments of this specification;

[0028] Figure 21 is a schematic diagram of an exemplary sensing device including a droplet according to some embodiments of the present specification;

[0029] Figure 22 is a schematic diagram of an exemplary sensing device including a droplet according to some embodiments of the present specification;

[0030] Figure 23A is a schematic diagram of an exemplary sensing device including a liquid film according to some embodiments of the present specification;

[0031] Figure 23B is a schematic diagram of an exemplary sensing device including a liquid film according to some embodiments of the present specification;

[0032] Figure 24A is a schematic diagram of an exemplary sensing device including a liquid film according to some embodiments of the present specification;

[0033] Figure 24B is a schematic diagram of an exemplary sensing device including a liquid film according to some embodiments of the present specification;

[0034] Figure 25 is a schematic structural diagram of a sensing device according to some embodiments of this specification;

[0035] Figure 26A Schematic diagram of multiple pipeline structures according to some embodiments of this specification;

[0036] Figure 26B Schematic diagram of multiple pipeline structures according to some embodiments of this specification;

[0037] Figure 27 is a mechanical equivalent schematic diagram of a sensing device according to some embodiments of this specification;

[0038] Figure 28 is a frequency response curve of a sensing device according to some embodiments of this specification;

[0039] Figure 29A Schematic diagram of the vibration direction of the sensing device at the resonance peak according to some embodiments of this specification;

[0040] Figure 29B A schematic diagram of the vibration direction of a sensing device in a resonance valley according to some embodiments of this specification;

[0041] Figure 30 is a schematic structural diagram of a sensing device according to some embodiments of this specification;

[0042] Figure 31A yes Figure 25 Schematic diagram of the structure of part A;

[0043] Figure 31B yes Figure 25Schematic diagram of the structure of part A;

[0044] Figure 32A is a schematic diagram of a vibration pickup structure according to some embodiments of this specification;

[0045] Figure 32B is a schematic diagram of a vibration pickup structure according to some embodiments of this specification;

[0046] Figure 33 is a schematic diagram of a vibration pickup structure according to some embodiments of this specification;

[0047] Figure 34A According to some embodiments of this specification Figure 33 Cross-section of the middle BB;

[0048] Figure 34B According to some embodiments of this specification Figure 33 Cross-section of the middle BB;

[0049] Figure 34C According to some embodiments of this specification Figure 33 Cross-section of the middle BB;

[0050] Figure 34D According to some embodiments of this specification Figure 33 Cross-section of the middle BB;

[0051] Figure 35A is a schematic structural diagram of a sensing device according to some embodiments of this specification;

[0052] Figure 35B is a schematic structural diagram of a vibration pickup structure according to some embodiments of this specification;

[0053] Figure 36A is a schematic structural diagram of a sensing device according to some embodiments of this specification;

[0054] Figure 36B is a schematic structural diagram of a sensing device according to some embodiments of this specification;

[0055] Figure 37 is a schematic structural diagram of a sensing device according to some embodiments of this specification;

[0056] Figure 38 is a schematic structural diagram of a sensing device according to some embodiments of this specification;

[0057] Figure 39 is a frequency response curve of a sensing device according to some embodiments of this specification;

[0058] Figure 40is a schematic structural diagram of a sensing device according to some embodiments of this specification;

[0059] Figure 41 is a schematic structural diagram of a sensing device according to some embodiments of this specification;

[0060] Figure 42 is a schematic structural diagram of a sensing device according to some embodiments of this specification;

[0061] Figure 43 It is a schematic structural diagram of a sensing device according to some embodiments of this specification. DETAILED DESCRIPTION

[0062] To more clearly illustrate the technical solutions of the embodiments of this application, the following is a brief introduction to the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0063] It should be understood that the terms "system," "device," "unit," and / or "module" used herein are a method for distinguishing different components, elements, parts, portions, or assemblies at different levels. However, if other terms can achieve the same purpose, the terms may be replaced by other expressions.

[0064] As used in this application and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not intended to refer to the singular but may include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0065] The embodiments of this specification describe a sensing device. In some embodiments, the sensing device may include a shell having a receiving cavity inside the shell. In some embodiments, the sensing device may further include a transducer unit, and the transducer unit may include a vibration pickup structure for picking up the vibration of the shell and generating an electrical signal. The transducer unit may receive the vibration of the shell and convert it into an electrical signal output. In some embodiments, the transducer unit may be separated into a front cavity and a rear cavity located on opposite sides of the vibration pickup structure in the receiving cavity, and at least one cavity in the front cavity or the rear cavity is filled with liquid, and the liquid is in contact with the vibration pickup structure. In some embodiments, the sensing device may further include one or more pipe structures, each of which may be configured to connect the receiving cavity with the outside of the shell, and the liquid is at least partially located in one or more pipe structures. For ease of understanding, the shell and the transducer unit may be regarded as a sensor, wherein the vibration of the vibration pickup structure has a first resonant frequency, that is, the frequency response curve of the vibration pickup structure has a first resonant peak at the first resonant frequency. The fluid region corresponding to each pipe structure (including the interior of the pipe structure cavity and the fluid region close to the pipe structure, see for details) Figure 25The liquid within the housing (and related descriptions) and the exterior of the housing to which the pipe structure communicates (e.g., the air outside the housing) can be approximately considered a resonant system attached to the sensor, such that the frequency response curve of the sensor device has additional resonant peaks and resonant valleys in addition to the first resonant peak. In some embodiments, the resonant frequencies corresponding to the resonant peaks and resonant valleys are lower than the first resonant frequency, significantly improving the response of the sensor device in the frequency range before the first resonant peak appears on the frequency response curve. In some embodiments, when the pipe structure can include multiple pipe structures, the multiple pipe structures correspond to multiple resonant systems, and the multiple resonant systems can provide the sensor with multiple additional resonant peaks and resonant valleys. In some embodiments, at least one of the resonant frequencies corresponding to the multiple resonant peaks and resonant valleys is lower than the first resonant frequency. In some embodiments, the resonant system corresponding to the pipe structure can be applied to different types of sensors (e.g., piezoelectric sensors, capacitive sensors, electrodynamic sensors, eddy-current sensors, and inductive sensors), thereby causing the frequency response curve of the sensor to have multiple resonant peaks and resonant valleys, thereby improving the frequency response of the sensor in the frequency range lower than the first resonant frequency. Furthermore, by setting different pipeline structures, it is possible to make the difference between multiple resonance peaks and resonance valleys larger, that is, the Q value is larger. In this way, when the sensing device collects vibration signals, it will show different sensitivities to vibration signals of different frequency components, and the generated electrical signal will appear as a fusion of multiple "sub-band" signals. Molecular band signals with steeper boundaries can be intercepted by only using low-order filters in the back-end circuit or algorithm. In some embodiments, the sensing device involved in this specification can be used as an inertial sensor. In some embodiments, the sensing device can be applied to common scenarios of inertial sensors such as accelerometers, energy harvesters, and gyroscopes. In some embodiments, the sensing device can also be applied to audio devices such as bone-conducting microphones, speakers, and hearing aids to enhance the sensitivity of the audio equipment. In some embodiments, the sensing device can also be applied to electronic devices with audio functions (for example, headphones, glasses, smart helmets, speakers, tablets, mobile phones, etc.).

[0066] Figure 1 is a schematic diagram of an exemplary sensing device according to some embodiments of the present specification.

[0067] The sensing device 100 can generate deformation and / or displacement based on external signals, such as mechanical signals (such as pressure, mechanical vibration), acoustic signals (such as sound waves), electrical signals, optical signals, thermal signals, etc. The deformation and / or displacement can be further converted into a target signal by the transducer component of the sensing device 100. In some embodiments, the target signal can be an electrical signal, a mechanical signal (such as mechanical vibration), an acoustic signal (such as sound waves), an electrical signal, an optical signal, a thermal signal, etc. In some embodiments, the sensing device 100 can be a microphone (such as an air conduction microphone or a bone conduction microphone), a speaker (such as an air conduction speaker or a bone conduction speaker), an accelerometer, a pressure sensor, a hydrophone, an energy harvester, a gyroscope, etc. An air conduction microphone or an air conduction speaker refers to a microphone or speaker in which sound waves are conducted through air. A bone conduction microphone or a bone conduction speaker refers to a microphone or speaker in which sound waves are conducted in a solid (such as bone) in the form of mechanical vibrations.

[0068] For example, Figure 1 As shown, the sensing device 100 may include a housing 110 , a transducer unit 120 , and a processor 130 (eg, an integrated circuit (IC)).

[0069] The housing 110 may be a regular or irregular three-dimensional structure having an internal accommodating cavity (i.e., a hollow portion). For example, it may be a hollow frame structure, including but not limited to regular shapes such as a rectangular frame, a circular frame, a regular polygonal frame, and any irregular shape. The housing 110 may be used to accommodate the energy displacing unit 120 and / or the processor 130. In some embodiments, the housing 110 may be packaged in one or more ways such as plastic packaging and metal packaging. In some embodiments, the accommodating cavity of the housing 110 may be filled with one or more of a gas, a liquid, a solid, and the like. In some embodiments, the accommodating cavity may also be a vacuum structure.

[0070] The transducer unit 120 may be located in the housing cavity of the housing 110 or at least partially suspended in the housing cavity of the housing 110. The transducer unit 120 may be used to convert an external signal into a target signal. Taking a bone conduction microphone (also called a vibration sensing device) as an example, the external signal is a mechanical vibration signal and the target signal is an electrical signal. The transducer unit 120 may include a vibration pickup structure. The vibration pickup structure may have a certain elasticity. For example, the vibration pickup structure may be a vibration rod (such as a cantilever beam), a vibration membrane (such as a piezoelectric membrane), a vibration block, etc. The vibration pickup structure may generate deformation and / or displacement in response to the mechanical vibration signal. The transducer unit 120 may convert the deformation and / or displacement into a target signal (for example, an electrical signal). In some embodiments, the transducer unit 120 may include a piezoelectric transducer, an acoustic transducer, an electromagnetic transducer, a capacitive transducer, etc. In some embodiments, the transducer unit 120 may be electrically connected to the processor 130 via a lead 140.

[0071] The processor 130 may be configured to process data and / or signals. In some embodiments, the processor 130 may include one or more of a bipolar integrated circuit (e.g., a logic gate circuit, an emitter-coupled logic circuit, etc.), a unipolar integrated circuit (e.g., a field-effect transistor integrated circuit, an n-channel field-effect transistor integrated circuit, etc.), and the like.

[0072] In some embodiments, the processor 130 may be located in the accommodating cavity of the shell 110 or at least partially suspended in the accommodating cavity of the shell 110. In some embodiments, the processor 130 may also be located outside the accommodating cavity of the shell 110. For example, the processor 130 may be disposed on the outer surface of the shell 110, and it may be connected to the transducer unit 120 for signal transmission via a lead. In some embodiments, the processor 130 may process a target signal. Continuing with the example of a bone conduction microphone, the processor 130 may convert the target signal into voice data, or send the target signal or voice data corresponding to the target signal to the cloud and / or other terminal devices. In some embodiments, the transducer unit 120 and the processor 130 may be arranged in parallel (such as Figure 1 as shown), up and down arrangement or internal integration and other settings.

[0073] In some embodiments, the sensing device 100 may further include a lead 140. The lead 140 may be used to connect the transducer unit 120 and the processor 130 signals. For example, the lead 140 may transmit a target signal or other signals (such as configuration instructions, acquisition instructions, etc.). In some embodiments, the lead 140 may not be necessary, and its function may be achieved through other connection methods. For example, the transducer unit 120 and the processor 130 may be stacked up and down, and the transducer unit 120 and the processor 130 may transmit data through a setting in which the ports of the two are in direct contact, thereby replacing the function of the lead 140.

[0074] Figure 2 is a schematic structural diagram of an exemplary microphone according to some embodiments of this specification.

[0075] like Figure 2 As shown, the microphone 200 may include a housing 210 , a transducer unit 220 , a processor 230 , and a printed circuit board (PCB) 240 .

[0076] PCB 240 can be a phenolic PCB paper substrate, a composite PCB substrate, a glass fiber PCB substrate, a metal PCB substrate, a build-up multilayer PCB substrate, or the like. In some embodiments, PCB 240 can be an FR-4 grade glass fiber PCB substrate made of epoxy fiberglass cloth. Circuitry and other components of microphone 200 can be provided on PCB 240 (e.g., by laser etching, chemical etching, etc.). In some embodiments, PCB 240 can also be a flexible printed circuit board (FPC). In some embodiments, transducer unit 220 and processor 230 are fixedly connected to PCB 240 via transducer unit fixing adhesive 250 and processor fixing adhesive 260, respectively. In some embodiments, transducer unit fixing adhesive 250 and / or processor fixing adhesive 260 can be conductive adhesive (e.g., conductive silver adhesive, copper powder conductive adhesive, nickel-carbon conductive adhesive, silver-copper conductive adhesive, etc.). The conductive adhesive can be conductive glue, conductive adhesive film, conductive rubber ring, conductive tape, etc. The transducer unit 220 and / or processor 230 are electrically connected to other components via the circuitry provided on PCB 240. The transducer unit 220 and the processor 230 may be directly connected via a wire 270 (eg, a gold wire, a copper wire, an aluminum wire, etc.).

[0077] The housing 210 may be a regular or irregular three-dimensional structure having a cavity (i.e., a hollow portion) inside. For example, it may be a hollow frame structure, including but not limited to regular shapes such as a rectangular frame, a circular frame, a regular polygonal frame, and any irregular shape. The housing 210 is covered above the PCB 240 to seal the transducer unit 220, the processor 230, the PCB 240, and the circuits and other components disposed thereon. The housing 210 may be made of metal (e.g., stainless steel, copper, etc.), plastic (e.g., polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), and acrylonitrile-butadiene-styrene copolymer (ABS), etc.), composite materials (e.g., metal-based composite materials or non-metal-based composite materials), etc. In some embodiments, the material used for the housing 210 is brass.

[0078] The transducer unit 220 can convert external vibration signals into electrical signals. Taking a bone conduction microphone as an example, the transducer unit 220 may include a base structure, a laminated structure (i.e., a vibration pickup structure), and at least one damping structure layer. In some embodiments, the base structure and the laminated structure may be located within the housing 210 of the bone conduction microphone, with the base structure fixedly connected to the inner wall of the housing 210, and the laminated structure supported by the base structure. In some embodiments, at least a portion of the laminated structure is physically connected to the base structure. As used herein, "connection" may refer to connections between different parts of the same structure, or to separate components or structures that are separately manufactured and then fixedly connected by welding, riveting, clamping, bolting, adhesive bonding, or the like, or to physical deposition (e.g., physical vapor deposition) or chemical deposition (e.g., chemical vapor deposition) of a first component or structure onto a second component or structure during the manufacturing process. In some embodiments, at least a portion of the laminated structure may be fixed to the upper or lower surface of the base structure, or at least a portion of the laminated structure may be fixed to the sidewall of the base structure. For example, the laminated structure may be a cantilever beam (also known as a piezoelectric beam), which may be a plate-like structure, with one end of the cantilever beam connected to the upper surface, lower surface, or sidewall of the base structure where the cavity of the base structure is located, and the other end of the cantilever beam is not connected to or in contact with the base structure, so that the other end of the cantilever beam is suspended in the cavity of the base structure. For another example, a bone conduction microphone may include a diaphragm layer (also known as a suspended membrane structure), which is fixedly connected to the base structure, and the laminated structure is disposed on the upper surface or lower surface of the suspended membrane structure. For another example, the laminated structure may include a mass element and one or more support arms, the mass element being fixedly connected to the base structure via one or more support arms, one end of the support arm being connected to the base structure, and the other end of the support arm being connected to the mass element, so that part of the mass element and the support arm are suspended in the cavity of the base structure. It should be noted that the terms "located in the cavity" or "suspended in the cavity" in this application may mean suspended inside, below, or above the cavity.

[0079] In some embodiments, the laminate structure may include a vibration unit and a signal conversion unit (also referred to as an acoustic transducer unit). The vibration unit refers to the portion of the laminate structure that is easily deformed by an external force, and the vibration unit can be used to transfer the deformation caused by the external force to the signal conversion unit. The signal conversion unit refers to the portion of the laminate structure that converts the deformation of the vibration unit into an electrical signal. Specifically, the base structure can generate vibrations based on an external vibration signal, and the vibration unit deforms in response to the vibration of the base structure; the signal conversion unit generates an electrical signal based on the deformation of the vibration unit. It should be noted that the description of the vibration unit and the signal conversion unit here is only for the purpose of conveniently introducing the working principle of the laminate structure, and does not limit the actual composition and structure of the laminate structure. In some embodiments, the vibration unit may not be necessary, and its function can be completely implemented by the signal conversion unit. The signal conversion unit can directly generate an electrical signal in response to the vibration of the base structure. For example, the signal conversion unit can be a piezoelectric cantilever beam.

[0080] In some embodiments, the vibration unit and the signal conversion unit overlap to form a stacked structure. The signal conversion unit can be located on an upper layer of the vibration unit or on a lower layer of the vibration unit.

[0081] In some embodiments, the signal conversion unit may include at least two electrode layers (e.g., a first electrode layer and a second electrode layer) and a piezoelectric layer, wherein the piezoelectric layer may be located between the first electrode layer and the second electrode layer. A piezoelectric layer refers to a structure that can generate a voltage at its two end surfaces when subjected to an external force. In some embodiments, the piezoelectric layer can generate a voltage under the deformation stress of the vibration unit, and the first electrode layer and the second electrode layer can collect the voltage (electrical signal).

[0082] Taking a bone conduction microphone as an example, the vibration unit may include at least one elastic layer. The signal conversion unit may include a first electrode layer, a piezoelectric layer, and a second electrode layer arranged in sequence from top to bottom. The elastic layer is located on the surface of the first electrode layer or the second electrode layer. The elastic layer may deform during vibration. The piezoelectric layer generates an electrical signal based on the deformation of the elastic layer. The first electrode layer and the second electrode layer may collect the electrical signal. As an example only, the vibration unit may include a first elastic layer and a second elastic layer arranged in sequence from top to bottom. The first elastic layer and the second elastic layer may be a plate-like structure made of semiconductor material. In some embodiments, the semiconductor material may include silicon dioxide, silicon nitride, gallium nitride, zinc oxide, silicon carbide, etc. In some embodiments, the materials of the first elastic layer and the second elastic layer may be the same or different.

[0083] In some embodiments, the piezoelectric layer may be a piezoelectric polymer film obtained by a semiconductor deposition process (eg, magnetron sputtering, MOCVD). In some embodiments, the material of the piezoelectric layer may include piezoelectric crystal materials and piezoelectric ceramic materials.

[0084] The damping structure layer may refer to a structure having damping properties. In some embodiments, the damping structure layer may be a membrane-like structure or a plate-like structure. Furthermore, at least one side of the damping structure layer may be connected to the base structure. In some embodiments, the damping structure layer may be located on the upper surface and / or lower surface of the laminate structure or between multiple layers of the laminate structure. For example, when the laminate structure is a cantilever beam, the damping structure layer may be located on the upper surface and / or lower surface of the cantilever beam. For another example, when the laminate structure is a support arm and a mass element, when the mass element protrudes downward relative to the support arm, the damping structure layer may be located on the lower surface of the mass element and / or the upper surface of the support arm. In some embodiments, for macro-sized laminate structures and base structures, the damping structure layer may be directly bonded to the base structure or laminate structure. In some embodiments, for micro-electromechanical systems (MEMS) devices, the damping structure layer may be connected to the laminate structure and base structure using semiconductor processes, such as evaporation, spin coating, microassembly, etc. In some embodiments, the shape of the damping structure layer can be regular or irregular, such as circular, elliptical, triangular, quadrilateral, hexagonal, octagonal, etc. In some embodiments, the output effect of the electrical signal of the bone conduction microphone can be improved by selecting the material, size, thickness, etc. of the damping structure layer.

[0085] When the housing 210 of the bone conduction microphone is vibrated by an external force (for example, the vibration of a person's face when speaking drives the housing 210 to vibrate), the vibration of the housing 210 drives the base structure to vibrate. Due to the different properties of the laminated structure and the housing structure (or base structure), the laminated structure and the housing 210 cannot maintain completely consistent movement, resulting in relative motion, which in turn causes the vibration unit of the laminated structure to deform. Furthermore, when the vibration unit deforms, the piezoelectric layer of the signal conversion unit is subjected to the deformation stress of the vibration unit, generating an electric potential difference (voltage). At least two electrode layers (for example, a first electrode layer and a second electrode layer) located on the upper and lower surfaces of the piezoelectric layer in the signal conversion unit can collect this potential difference and convert the external vibration signal into an electrical signal.

[0086] The damping of the damping structure layer varies under different stress (deformation) states. For example, it exhibits greater damping under high stress or large amplitude. Therefore, the characteristics of the laminated structure in which the amplitude is small in the non-resonance region and large in the resonance region can be utilized. By adding a damping structure layer, the sensitivity of the bone conduction microphone in the non-resonance region can be reduced less while the quality factor Q value in the resonance region can be reduced, so that the frequency response of the bone conduction microphone is relatively flat across the entire frequency range. The bone conduction microphone can be applied to headphones (e.g., bone conduction headphones or air conduction headphones), glasses, virtual reality equipment, helmets, etc. The bone conduction microphone can be placed on the human head (e.g., face), neck, near the ears, and on the top of the head. The bone conduction microphone can pick up the vibration signal of the bones when a person speaks and convert it into an electrical signal to achieve sound collection. It should be noted that the base structure is not limited to a structure independent of the housing 210 of the bone conduction microphone. In some embodiments, the base structure can also be part of the housing 210 of the bone conduction microphone.

[0087] The processor 230 may obtain the electrical signal from the transducer unit 220 and perform signal processing. In some embodiments, the signal processing may include frequency modulation processing, amplitude modulation processing, filtering processing, noise reduction processing, etc.

[0088] Figure 3 is a schematic diagram of an exemplary equivalent vibration model of a transducer unit according to some embodiments of this specification.

[0089] The transducer unit 120 can be simplified and equivalent to Figure 3 The mass-spring-damper system shown in Figure 1 is subjected to forced vibration by an excitation force F. The motion of this system can be described by the following differential equation:

[0090]

[0091] Where M is the system mass, R is the system damping, K is the system elastic coefficient, F is the driving force amplitude, x is the system displacement, and ω is the external force circular frequency. Solving the above equation for the steady-state displacement yields:

[0092] x=x a cos(ωt-θ), (2)

[0093] in,

[0094] When the sensor device 100 is actually working, x corresponds to the deformation of the vibration-electrical signal conversion module of the transducer unit 120, and the magnitude of x ultimately corresponds to the magnitude of the electrical signal output. The displacement amplitude ratio (normalized) is:

[0095]

[0096] in, is the mechanical quality factor; is the static displacement amplitude (or the displacement amplitude when ω=0); ω0 is the system resonant frequency.

[0097] Figure 4 FIG is a schematic diagram of a displacement resonance curve of an exemplary sensor device according to some embodiments of this specification. The sensor device 100 is composed of transducer units with different parameters (elastic coefficient, mass, damping), and its normalized displacement resonance curve is as follows: Figure 4 The horizontal axis corresponds to the ratio of the frequency of the external force (or vibration) to the resonant frequency of the system. The vertical axis corresponds to the A value of formula (3). It can be seen that for different sensor devices 100, the transducer units 120 are different and have different mechanical quality factors Q m The value corresponds to different curves in the figure, and the displacement A is different. The ratio of the frequency of the external force (or vibration) to the resonant frequency of the system When Q is 1, the system resonates and the displacement change is the largest. m The larger the transducer unit, the larger the A value and the steeper the curve; m The smaller the value of the transducer unit, the smaller the A value and the flatter the curve. Therefore, the quality factor Q of the transducer unit 120 can be adjusted. m value (such as changing its structure) and adjusting the Q value.

[0098] The principle of microphone voltage signal generation is that the vibration-electrical signal conversion module (i.e., transducer unit) and the microphone housing generate relative displacement (for example, the electret microphone generates a voltage signal by deforming the diaphragm and changing the distance between the diaphragm and the substrate; the cantilever beam bone conduction microphone generates an electrical signal by deforming the cantilever vibration device to generate a piezoelectric effect). The greater the displacement, the greater the output signal. Obviously, the vibration-electrical signal conversion module of the microphone fully complies with the following. Figure 4 The displacement resonance curve.

[0099] When reduced When the resonant frequency is changed, the resonant frequency of the system decreases. When the resonant frequency is changed, the sensitivity of the signal before the resonant frequency increases, but after the resonant frequency, there is a frequency range where the sensitivity of the signal decreases. When adjusting the sensitivity by adjusting the resonant frequency of the sensor device 100, the frequency range must be taken into consideration. In some embodiments, the resonant frequency of the sensor device 100 is between 1500 Hz and 6000 Hz. In some embodiments, the resonant frequency of the sensor device 100 is between 1500 Hz and 3000 Hz. In some embodiments, the resonant frequency of the sensor device 100 is between 2000 Hz and 2500 Hz.

[0100] Figure 5is a mechanical equivalent schematic diagram of an exemplary sensing device according to some embodiments of this specification.

[0101] In some embodiments, the sensing device 500 may include a transducer unit 520 and an additional resonant system 530 (also referred to as a first resonant system 530). In some embodiments, the sensing device 500 may be considered to include the first resonant system 530 on the basis of the transducer unit 520. For example, in this embodiment, the first resonant system 530 may be a spring (K m4 )-Mass(M m4 )-damping(R m4 ) system. The first resonance system 530 can be coupled between the shell (not shown in the figure) and the transducer unit 520. Due to the action of the first resonance system 530, when the shell receives an external vibration signal, the external vibration signal will be transmitted to the transducer unit 520 through the shell area connected to the transducer unit 520 and the shell area connected to the first resonance system 530, respectively. Therefore, the mechanical response of the sensing device 500 is changed compared to the sensing device 100. Accordingly, the electrical, acoustic and / or thermal response of the sensing device 500 is changed compared to the sensing device 100.

[0102] In some embodiments, the first resonant system 530 may be formed by filling a cavity of the housing with liquid. For example, the liquid fills the cavity in the housing, and the transducer unit 520 is wrapped in the liquid.

[0103] Figure 6 Schematic diagram of a sensing device filled with liquid according to some embodiments of this specification. Figure 6 As shown, liquid 610 can be selected from liquids that have safety properties (e.g., non-flammable and non-explosive) and stability properties (e.g., non-volatile and non-deteriorating at high temperatures). For example, liquid 610 can include oil (e.g., silicone oil, glycerin, castor oil, engine oil, lubricating oil, hydraulic oil (e.g., aviation hydraulic oil)), water (e.g., pure water, other inorganic or organic aqueous solutions (e.g., salt water)), oil-water emulsions, or other liquids that meet the performance requirements, or a combination of one or more thereof.

[0104] The density and kinematic viscosity of the liquid 610 are within a certain density range and kinematic viscosity range, respectively. In some embodiments, the density range and kinematic viscosity range can be set by the user or determined based on the performance of the sensor device 500 (e.g., sensitivity, noise floor level, resonance peak-to-peak value, resonance peak frequency range, peak-to-valley value and / or quality factor Q, etc.). In some embodiments, silicone oil can be used as the liquid 610. Silicone oil has the characteristics of high temperature resistance, low volatility, and a wide viscosity range. The density is about 0.94 kg / m 3 , a wide range of optional kinematic viscosities (e.g., 0.1-1000 stokes (cst)).

[0105] The liquid 610 can be injected into the housing cavity of the housing 510 in a specific manner. For a detailed description of injecting the liquid 610 into the housing cavity of the housing 510, please refer to other parts of this specification, such as Figure 11 and its description.

[0106] In some embodiments, the frequency response curve of the sensor device 500 includes at least two resonance peaks. The at least two resonance peaks include a first resonance peak and a second resonance peak. The resonance frequency corresponding to the first resonance peak is mainly related to the properties of the transducer unit 520 (for example, shape, material, structure, etc.). The second resonance peak is a resonance peak generated by the first resonance system 530, and its corresponding resonance frequency is mainly related to one or more mechanical parameters of the first resonance system 530 (for example, the spring equivalent to the resonance system (K)). m4 ), quality (M m4 ), damping (R m4 ) etc. To adapt the sensor device 500 to different scenarios, the resonant frequency corresponding to the first resonant peak (also referred to as the first resonant frequency) and the resonant frequency corresponding to the second resonant peak (also referred to as the second resonant frequency) may satisfy different relationships. For example, the second resonant frequency may be less than, equal to, or greater than the first resonant frequency.

[0107] For illustrative purposes only, due to the presence of the second resonance peak corresponding to the first resonance system 530, the frequency response curve of the sensor device 500, especially in the low and medium frequency bands where voice information is relatively rich, will be improved, so that its sensitivity will be improved. In addition, since the first resonance system 530 acts on the transducer unit 520, the vibration characteristics of the sensor device 500 will be changed compared to when there is no first resonance system 530. Specifically, the first resonance system 530 acts on the transducer unit 520, which can affect the mass, stiffness and / or damping of the sensor device 500, and the effect is equivalent to causing the Q value of the first resonance peak of the sensor device 500 to change relative to the Q value of the sensor device not connected to the first resonance system 530 (for example, the Q value is reduced). For more detailed descriptions of the frequency response curve of the sensor device 500 and the first resonance peak and the second resonance peak, please refer to other places in this application specification, such as Figure 9 and Figure 10 and its description.

[0108] In some embodiments, the first resonant system 530 can reduce external impacts received by the transducer unit 520 to protect the transducer unit 520. For example, if the first resonant system 530 is a liquid 610 that fills the chamber of the sensor device 500, the viscosity of the liquid 610 and its inherent stiffness, which is much lower than that of the device material, can improve the reliability of the sensor device 500 when receiving external impact loads (for example, a bone conduction microphone is required to withstand an acceleration of 10,000 g without damage). Specifically, the viscosity of the liquid 610 can absorb and dissipate some of the impact energy, thereby significantly reducing the impact load received by the transducer unit 520.

[0109] Furthermore, due to stress during processing, sensor device 100, particularly cantilever beam devices, often experiences deformation, such as bending (along length and width) and twisting. However, cantilever beam structures are commonly used in sensing devices such as bone conduction microphones and accelerometers. Since the housing of sensor device 500 is filled with liquid 610, the gravity, surface tension, and viscosity of liquid 610 can be utilized to correct device deformation, resulting in less deformation, more stable output, and closer to the actual design.

[0110] Figure 7 is a mechanical equivalent schematic diagram of an exemplary sensing device according to some embodiments of this specification. Figure 7 As shown, the sensing device 700 may include a transducer unit 720 and a second resonant system 740. In some embodiments, the sensing device 700 may be considered to be a first resonant system 530 adjusted on the basis of the transducer unit 720 to form the second resonant system 740. For example, in this embodiment, the second resonant system 740 is newly added with a spring (K) compared to the first resonant system 530. m3 ) and damping (R m3 ). The second resonance system 740 may be provided between the housing 710 and the transducer unit 720. For example, Figure 7 As shown, the spring (K m3 )-damping(R m3 ) can be combined with the spring (K m4 )-Mass(M m4 )-damping(R m4 ) are connected in series and indirectly act on the transducer unit 720. For another example, the spring (K m3 )-damping(R m3 ) can be combined with the spring (K m4 )-Mass(M m4 )-damping(R m4) are connected in series and directly act on the transducer unit 720. Due to the action of the second resonant system 740, when the shell 710 receives an external vibration signal, the external vibration signal will be transmitted to the transducer unit 720 through the shell area connected to the transducer unit 720 and the shell area connected to the second resonant system 740 through the second resonant system 740. Therefore, the mechanical response of the sensor device 700 is changed compared with the sensor device 500. Accordingly, the electrical, acoustic and / or thermal response of the sensor device 700 is changed compared with the sensor device 500. At the same time, due to the newly introduced spring (K m3 ) and damping (R m3 ), the vibration characteristics (e.g., stiffness-damping, etc.) of the sensing device 700 are changed compared to the sensing device 500.

[0111] In some embodiments, the second resonant system 740 can be formed by filling the receiving cavity of the sensor device 700 with different media. For example, the receiving cavity of the sensor device 700 can be partially filled with liquid to form the second resonant system 740 in which liquid and bubbles (also called air cavity) coexist in the receiving cavity. In this case, the liquid in the receiving cavity can be equivalent to the above-mentioned spring (K m4 )-Mass(M m4 )-damping(R m4 ), the bubble can be equivalent to the above spring (K m3 ) and damping (R m3 For another example, the accommodating chamber of the sensor device 700 may be filled with liquid, and the sensor device 700 may further include a pipe structure connecting the accommodating chamber with the outside of the housing, and the liquid is at least partially located in one or more pipe structures. In this case, the liquid in the accommodating chamber may be equivalent to the above-mentioned spring (K m4 )-Mass(M m4 )-damping(R m4 ), the liquid in the fluid region corresponding to the pipeline structure and the air corresponding to the pipeline structure can be equivalent to the above-mentioned spring (K m3 ) and damping (R m3 For another example, the receiving cavity of the sensing device 700 may be filled with mutually immiscible liquids of different densities to form the second resonant system 740. In some embodiments, the medium filled into the receiving cavity of the sensing device 700 may be set by the user or determined based on the performance of the sensing device 700 (e.g., sensitivity, noise floor level, resonance peak-to-peak value, frequency range of the resonance peak, peak-to-valley value, and / or quality factor Q, etc.).

[0112] Figure 8 FIG is a schematic diagram of a sensing device filled with liquid and bubbles according to some embodiments of this specification. Figure 8As shown, in the sensing device 700, the accommodating cavity of the shell 710 is filled with liquid 810 and air bubbles 820. The liquid 810 in the sensing device 700 can be the same type of liquid as or different type of liquid as that of the sensing device 500. For example, the sensing device 700 and the sensing device 500 are both filled with silicone oil of the same kinematic viscosity. For another example, the sensing device 700 and the sensing device 500 are respectively filled with different types of liquids 810 or the same liquid 810 of different kinematic viscosities (for example, silicone oils with kinematic viscosities of 0.65 cst and 200 cst, respectively). The liquid 810 and the air bubbles 820 can be injected or formed in the accommodating cavity of the shell 710 in a specific manner. Regarding the method of injecting or forming the liquid 810 and the air bubbles 820 in the accommodating cavity of the shell 710, please refer to the description elsewhere in this application specification, such as Figure 11 and its description.

[0113] In some embodiments, the frequency response curve of the sensor device 700 includes at least two resonance peaks. The at least two resonance peaks include a third resonance peak and a fourth resonance peak. The third resonance peak is the resonance peak corresponding to the transducer unit 720, and the fourth resonance peak is the resonance peak generated by the second resonance system 740.

[0114] In some embodiments, the third resonant frequency (the resonant frequency corresponding to the third resonant peak) and the fourth resonant frequency (the resonant frequency corresponding to the fourth resonant peak) of the sensing device 700 may satisfy different relationships. For example, when the second resonant system 740 is formed by the liquid 810 and the bubbles 820, due to the large compressibility of the bubbles 820 (compared to the case of the pure liquid 810) and the small stiffness, the sensing device 700 may have a resonant frequency in the low frequency or medium-low frequency band. For example, the fourth resonant frequency is a low frequency or a medium-low frequency, and the third resonant frequency may be greater than the fourth resonant frequency, for example, the third resonant frequency is in a higher frequency band. For another example, the third resonant frequency and the fourth resonant frequency are both medium-low frequencies. In this application, low frequency, medium-low frequency, and medium-high frequency refer to frequencies whose frequency values are within a certain range. For example, the frequency range corresponding to low frequency, medium-low frequency, or medium-high frequency is within 7000 Hz, within 5000 Hz, within 3000 Hz, within 1000 Hz, within 500 Hz, etc. For example, the frequency range corresponding to the higher frequency band is above 2000Hz, above 5000Hz, above 8000Hz, etc. The third resonant frequency is a higher frequency than the fourth resonant frequency. Optionally, the difference between the two resonant frequencies is 100-6000Hz. When the sensing device 700 has a resonant frequency in the low frequency or mid-low frequency range, its sensitivity at low frequency will be higher than that of the sensing device that is not provided with the second resonant system 740; when the sensing device 700 further has a resonant frequency in the high frequency or mid-high frequency range, its frequency response curve is also flatter in the range between the two resonant peaks, which is more conducive to the acquisition of effective voice signals in this frequency band.

[0115] In addition, since the second resonance system 740 acts on the transducer unit 720, the vibration characteristics of the sensor device 700 will be changed compared to the sensor device without the second resonance system 740. For example, the second resonance system 740 acts on the transducer unit 720, which can affect the stiffness and / or damping of the sensor device 700, and the effect is equivalent to causing the Q value of the third resonance peak of the sensor device 700 to change (for example, the Q value is reduced) relative to the sensor device without the second resonance system 740. For more detailed descriptions of the frequency response curve of the sensor device 700 and the third and fourth resonance peaks, please refer to other places in this application specification, such as Figure 9 and Figure 10 and its description.

[0116] In some embodiments, the second resonant system 740 can reduce external impacts on the transducer unit 720 to protect it. For example, if liquid 810 and air bubbles 820 are introduced into the housing 710, the sensor device 700 can be more resilient to external impact loads. Due to the viscosity of the liquid 810 and the high compressibility of the gas, they can absorb and dissipate some of the impact energy, significantly reducing the impact load on the transducer unit 720.

[0117] Furthermore, sensor device 700 often experiences deformation due to stress during processing. By injecting liquid 810 and bubbles 820 into the chamber, the gravity, surface tension, and viscosity of liquid 810 can be utilized to correct device deformation, minimizing deformation of sensor device 700 and achieving more stable output, closer to the actual design.

[0118] It should be noted that the above description of the sensor device 700 is merely illustrative and does not limit this specification to the embodiments described. It is understood that those skilled in the art, after understanding the principles of the system, may arbitrarily combine its structures and modules, or form subsystems connected to other modules without departing from these principles.

[0119] Figure 9 is an exemplary frequency response curve of the sensing device 500 or 700 according to some embodiments of this specification.

[0120] For example, Figure 9 As shown, dashed line 910 represents the frequency response curve of a sensor device without an equivalent resonant system, and solid line 920 represents the frequency response curve of sensor device 500 or 700. The horizontal axis represents frequency in Hertz (Hz), and the vertical axis represents sensitivity in decibels (dBV). Frequency response curve 910 includes a resonant peak 911. Frequency response curve 920 includes a first (or third) resonant peak 921 and a second (or fourth) resonant peak 922. For sensor device 500, the frequency corresponding to first resonant peak 921 is the first resonant frequency, and the frequency corresponding to second resonant peak 922 is formed by the action of first resonant system 530. For sensor device 700, the frequency corresponding to third resonant peak 921 is the third resonant frequency, and the frequency corresponding to fourth resonant peak 922 is formed by the action of second resonant system 740. The frequency corresponding to fourth resonant peak 922 is the fourth resonant frequency.

[0121] It should be noted that the second (or fourth) resonance peak 922 shown in the figure is to the left of the first (or third) resonance peak 921, that is, the frequency corresponding to the second (or fourth) resonance peak 922 is lower than the frequency corresponding to the first (or third) resonance peak. In some embodiments, by changing the mechanical parameters of the transducer unit or the first (or second) resonance system, the frequency corresponding to the second (or fourth) resonance peak 922 can be made higher than the frequency corresponding to the first (or third) resonance peak 921, that is, the second (or fourth) resonance peak 922 is to the right of the first (or third) resonance peak 921. For example, for a sensing device 500 filled with liquid, its second (or fourth) resonance peak 922 may be to the left or right of the first (or third) resonance peak 921, and its position may be related to the properties of the filled liquid (e.g., density, kinematic viscosity, volume, etc.). For example, if the density of the liquid decreases or the kinematic viscosity increases, its resonance peak will shift toward higher frequencies.

[0122] In some embodiments, the frequency corresponding to the resonance peak 911 is in the range of 100 Hz to 12,000 Hz. In some embodiments, the frequency corresponding to the resonance peak 911 is in the range of 1,000 Hz to 7,000 Hz. In some embodiments, the frequency corresponding to the resonance peak 911 is in the range of 3,000 Hz to 4,000 Hz.

[0123] In some embodiments, the frequency corresponding to the first (or third) resonance peak 921 is in the range of 100 Hz to 12,000 Hz. In some embodiments, the frequency corresponding to the first (or third) resonance peak 921 is in the range of 1,500 Hz to 7,000 Hz. In some embodiments, the frequency corresponding to the first (or third) resonance peak 921 is in the range of 3,000 Hz to 4,000 Hz.

[0124] In some embodiments, the resonant frequency (first resonant frequency or third resonant frequency) corresponding to the first (or third) resonant peak 921 is different from the resonant frequency corresponding to the resonant peak 911. For example, in a sensing device 500 in which the housing 110 cavity is filled with liquid, the liquid serves as the first resonant system 530. Since the liquid is not easily compressed, the rigidity of the system itself increases. Therefore, the first frequency corresponding to the first resonant peak 921 is greater than the resonant frequency corresponding to the resonant peak 911, that is, the first resonant peak 921 is shifted to the right relative to the resonant peak 911.

[0125] In some embodiments, the frequency corresponding to the second (or fourth) resonance peak 922 is in the range of 50 Hz to 12,000 Hz. In some embodiments, the frequency corresponding to the second (or fourth) resonance peak 922 is in the range of 1,000 Hz to 3,000 Hz. In some embodiments, the frequency corresponding to the second (or fourth) resonance peak 922 is in the range of 1,500 Hz to 2,000 Hz.

[0126] In some embodiments, the fourth resonant frequency is lower than the second resonant frequency. For a sensing device 500 in which the housing 510 cavity is filled with liquid, the liquid serves as the first resonant system 530. In contrast, in a sensing device 700 in which the housing 710 cavity contains both liquid and bubbles, the liquid and bubbles each serve as the second resonant system 740. The overall stiffness of the combined system is lower than that of the liquid, and therefore the fourth resonant frequency is lower than the second resonant frequency.

[0127] In some embodiments, the output quality of the sensing device 500 or 700 can be improved by adjusting the structure and material of the transducer unit, as well as one or more mechanical parameters (e.g., the type of filling liquid, bubble size, etc.) in the first (or second) resonant system, to make the gap between the two resonant peaks 921 and 922 on the frequency response curve 920 relatively flat. In some embodiments, the sensitivity difference between the valley between the resonant peaks 921 and 922 and the peak value of the higher of the resonant peaks 921 and 922 is no greater than 30 dBV, and the ratio of the sensitivity difference to the peak value of the higher of the resonant peaks 921 and 922 is no greater than 0.2. In some embodiments, the sensitivity difference between the valley between the resonant peaks 921 and 922 and the peak value of the higher of the resonant peaks 921 and 922 is no greater than 10 dBV, and the ratio of the sensitivity difference to the peak value of the higher of the resonant peaks 921 and 922 is no greater than 0.1. In some embodiments, the sensitivity difference between the valley between the resonance peaks 921 and 922 and the peak of the higher one of the resonance peaks 921 and 922 is no greater than 5 dBV, and the ratio of the sensitivity difference to the peak of the higher one is no greater than 0.05.

[0128] Accordingly, when the difference in resonant frequencies corresponding to resonant peaks 921 and 922 (the frequency of resonant peak 921 is represented by f0 (which is close to resonant peak 911), the frequency of resonant peak 922 is represented by f1, and the difference in resonant frequencies corresponding to resonant peaks 921 and 922 is represented by frequency difference Δf1) is within a certain range, the frequency response curve between resonant peaks 921 and 922 can be relatively flat. In some embodiments, the frequency difference Δf1 is within the range of 200-3000 Hz, and the ratio of the frequency difference Δf1 to f0 is within the range of 0.2-0.7. In some embodiments, the frequency difference Δf1 is within the range of 1000-1500 Hz, and the ratio of the frequency difference Δf1 to f0 is within the range of 0.35-0.6.

[0129] like Figure 9As shown, compared to frequency response curve 910, frequency response curve 920 exhibits a higher and more stable sensitivity improvement (i.e., difference, represented by ΔV1) within the frequency range within the resonant frequency f1 corresponding to the second (or fourth) resonant peak 922. In some embodiments, ΔV1 is within the range of 10 dBV to 60 dBV. In some embodiments, ΔV1 is within the range of 20 dBV to 40 dBV. In some embodiments, ΔV1 is within the range of 30 dBV to 40 dBV.

[0130] The presence of the first resonant system 530 or the second resonant system 740 suppresses the resonant peak corresponding to the transducer unit of the sensor device 500 or 700, resulting in a relatively low Q value at the first (or third) resonant peak 921 of the frequency response curve 920. This flattens the frequency response curve within a desired frequency band (e.g., mid- and low-frequency bands), and the difference between the highest peak and the lowest valley of the overall frequency response curve 920 (also known as the peak-to-valley value, represented by ΔV2) is within a certain range. In some embodiments, the peak-to-valley value does not exceed 30 dBV, and the ratio of the peak-to-valley value to the peak value of the highest peak does not exceed 0.2. In some embodiments, the peak-to-valley value does not exceed 10 dBV, and the ratio of the peak-to-valley value to the peak value of the highest peak does not exceed 0.1. In some embodiments, the peak-to-valley value does not exceed 5 dBV, and the ratio of the peak-to-valley value to the peak value of the highest peak does not exceed 0.05.

[0131] For the sensor device 700, in some embodiments, the frequency corresponding to the fourth resonance peak 922 (i.e., the fourth resonance frequency) is a mid-low frequency, and the frequency corresponding to the third resonance peak 921 (i.e., the third resonance frequency) is a mid-high frequency. In some embodiments, the difference between the minimum sensitivity of the frequency response curve 920 within the frequency range up to the resonance frequency f1 and the peak value of the fourth resonance peak is no greater than 30 dBV, and the ratio thereof is no greater than 0.2. In some embodiments, the difference between the minimum sensitivity of the frequency response curve 920 within the frequency range up to the resonance frequency f1 and the peak value of the fourth resonance peak is no greater than 10 dBV, and the ratio thereof is no greater than 0.1.

[0132] In some embodiments, the frequency response of the sensing device 500 or 700 can be described by one or more of the parameters associated with the curve 920, such as the peak value and frequency of the first (or third) resonance peak 921, the peak value and frequency of the second (or fourth) resonance peak 922, the Q value, Δf1, ΔV1, ΔV2, the ratio of Δf1 to f0, the ratio of the peak-to-valley value to the peak value of the highest peak, the first-order coefficient, the second-order coefficient, the third-order coefficient of the equation determined by fitting the frequency response curve, etc. In some embodiments, the frequency response of the sensing device 500 or 700 can be related to the properties of the liquid filled therein and / or the parameters of the transducer unit. The liquid properties can include, for example, the liquid density, the liquid kinematic viscosity, the liquid volume, the presence of bubbles, the bubble volume, the bubble location, the number of bubbles, etc. The parameters of the transducer unit can include, for example, the mass, size, stiffness, etc. of the transducer unit (e.g., a cantilever beam). In some embodiments, the frequency response of the sensing device 500 or 700 can also be related to parameters such as the internal structure (e.g., the shape of the accommodating cavity), size, and stiffness of the housing.

[0133] In some embodiments, to obtain an ideal output frequency response (e.g., frequency response curve 920) for sensing device 500 or 700, the ranges of the aforementioned parameters affecting the frequency response (also known as frequency response influencing factors, including, for example, the properties of the filling liquid and / or the parameters of the transducer element) can be determined through computer simulation, phantom experiments, and other methods. In some embodiments, the influence of each factor on the frequency response of sensing device 500 or 700 can be individually determined by controlling variables based on simulation. For example, the performance of sensing devices with different chamber structures can be tested under the same liquid and filled conditions. For another example, the performance of devices with different housing stiffness characteristics can be tested under the same liquid and filled conditions. For another example, the performance of sensing devices with the same housing size can be tested under different conditions of being filled with liquid and filled with liquid and bubbles. For another example, the performance of sensing devices with different bubble sizes can be tested under the condition that the bubbles do not cover the transducer element (e.g., piezoelectric transducer). For another example, the performance of sensing devices with different bubble sizes can be tested under the condition that the bubbles cover the transducer element (e.g., piezoelectric transducer).

[0134] In some embodiments, some factors are correlated with the effects of other factors on the frequency response of the sensing device 500 or 700. Therefore, the effects of these parameter pairs or groups on the frequency response of the sensing device 500 or 700 can be determined using corresponding parameter pairs or groups. For example, as the housing height increases, the volume of the accommodating cavity increases, the housing mass increases, and the volume of the liquid filled therein also increases accordingly. Therefore, the housing height, housing mass, and liquid volume (or the ratio of any two of these parameters, or the product of at least two of these parameters) can be used as a parameter group to test their effect on the performance of the sensing device. For another example, liquid viscosity and density can be used as a parameter pair to test the effect of this parameter pair (or their ratio, product, etc.) on the frequency response of the sensing device 500 or 700.

[0135] In some embodiments, the effect of parameter pairs or parameter groups corresponding to each factor or multiple factors on the frequency response of the sensor device 500 or 700 can be determined by means of a phantom test.

[0136] For example, for a sensor device 500 filled with liquids of varying viscosities, the greater the liquid viscosity, the greater the system damping and the smaller the Q value of the frequency response of the sensor device 500. For a sensor device 700 filled with liquid and bubbles, within a certain kinematic viscosity range, the greater the kinematic viscosity of the filled liquid, the greater the improvement in sensitivity of the sensor device 700.

[0137] In some embodiments, the kinematic viscosity of the liquid may be 0.1-5000 cSt. In some embodiments, the kinematic viscosity of the liquid may be 0.1-1000 cSt. In some embodiments, the kinematic viscosity of the liquid may be 0.3-1000 cSt. In some embodiments, the kinematic viscosity of the liquid may be 0.5-500 cSt. In some embodiments, the kinematic viscosity of the liquid may be 0.5-200 cSt. In some embodiments, the kinematic viscosity of the liquid may be 50-200 cSt.

[0138] For example, for the liquid-filled sensing device 500 , taking a bone conduction microphone or a single-axis accelerometer as an example, within a certain range, the length of the cantilever beam becomes shorter and the overall effective frequency band is expanded.

[0139] In some embodiments, the cantilever beam thickness, width, and length may be 0.5 μm-3 mm, 50 μm-500 mm, and 200 μm-1 cm, respectively. In some embodiments, the cantilever beam thickness, width, and length may be 1 μm-100 μm, 100 μm-10 mm, and 400 μm-20 mm, respectively. In some embodiments, the cantilever beam thickness, width, and length may be 2 μm-5 μm, 200 μm-500 μm, and 800 μm-1000 μm, respectively.

[0140] For example, for the sensor device 500 filled with liquid, by increasing the size of the accommodating cavity, the sensitivity of the sensor device at the intermediate frequency can be improved, and the frequency response suppression effect of the liquid on the sensor device at the intermediate frequency can be reduced, making the frequency response curve flatter.

[0141] For example, for a sensor device 500 filled with liquid and having different accommodating cavity heights, within a certain range, the higher the accommodating cavity height, the higher the mid- and low-frequency output sensitivity of the sensor device 500 .

[0142] In some embodiments, the length, width, and height of the accommodating cavity of the sensing device are 1-30 mm, 1-30 mm, and 0.5-30 mm, respectively. In some embodiments, the length, width, and height of the accommodating cavity of the sensing device are 8-10 mm, 5-10 mm, and 1-5 mm, respectively. Optionally, the accommodating cavity of the sensing device has a larger size. In some embodiments, the length, width, and height of the accommodating cavity of the sensing device are 10-200 mm, 10-100 mm, and 10-100 mm, respectively. In some embodiments, the length, width, and height of the accommodating cavity of the sensing device are 10-50 mm, 10-30 mm, and 10-30 mm, respectively.

[0143] For example, compared to the fully liquid-filled sensor device 500, the sensor device 700 filled with liquid and bubbles may have a higher overall output gain due to the fact that gas is easily compressible and has low rigidity, while liquid is not easily compressible. This may result in excessive stiffness and overdamping. For example, in some embodiments, the second resonance peak of the sensor device 500 may disappear due to overdamping, thereby affecting the sensitivity of the sensor device 500 at mid- and low-frequency levels.

[0144] For example, in the sensing device 700 filled with liquid and bubbles, when the bubbles do not cover the transducer unit (eg, piezoelectric transducer), the sensitivity of the sensing device 700 increases as the volume of the bubbles increases.

[0145] In some embodiments, the ratio of the volume of the bubbles to the volume of the liquid may be 5% to 90%. In some embodiments, the ratio of the volume of the bubbles to the volume of the liquid may be 30% to 50%.

[0146] In some embodiments, the bubbles may be located at different positions within the sensing device 700. For example, the bubbles may be located inside the liquid. For another example, the bubbles may be located between the liquid and the shell. In some embodiments, the transducer unit 720 may separate the accommodating cavity into a front cavity and a rear cavity located on opposite sides of the vibration pickup structure. In this specification, the rear cavity refers to a closed or semi-closed space formed by the base of the transducer unit and the vibration pickup structure (such as a cantilever beam). For example, taking a bone conduction microphone as an example, the accommodating cavity can be divided into a front cavity and a rear cavity with the plane where the cantilever beam is located as the dividing plane. For the sensing device 700 filled with liquid and bubbles, when the bubbles are located in the front cavity of the sensing device and are not in contact with the transducer unit (for example, the vibration pickup structure), the sensitivity gradually increases with the increase of bubbles.

[0147] In some embodiments, when bubbles of a certain size are provided in both the front and rear cavities of the liquid- and bubble-filled sensor device 700, a large gain in the low-frequency portion can be achieved, and the intermediate frequency effectively suppresses the Q value of the resonance peak of the sensor device 700, but does not suppress the sensitivity of other regions outside the resonance peak region of the corresponding sensor device 700, thereby making the frequency response of the sensor device 700 relatively flat in the range from low frequency to intermediate frequency.

[0148] In some embodiments, the ratio of the volume of the bubbles in the front cavity and the back cavity to the volume of the liquid can be 5%-95%. In some embodiments, the ratio of the volume of the bubbles in the front cavity and the back cavity to the volume of the liquid can be 30%-50%.

[0149] It should be noted that the above description of the frequency response curves of sensor devices 500 or 700 is merely illustrative and does not limit this specification to the illustrated embodiments. It is understood that those skilled in the art, after understanding the principles of the system, may arbitrarily adjust its structure and composition without departing from these principles. Such variations are within the scope of protection of this application.

[0150] Figure 10 is an exemplary frequency response curve of the sensing device 500 or 700 according to some embodiments of this specification.

[0151] like Figure 10As shown, dotted line 1010 represents the frequency response curve of a sensor device without an equivalent resonant system, and solid line 1020 represents the frequency response curve of sensor device 500 or 700. Frequency response curve 1010 includes a resonant peak 1011. In some embodiments, the higher resonant frequency corresponding to the sensor device without an equivalent resonant system is not in the desired frequency range (e.g., 100-5000 Hz, 500-7000 Hz, etc.). In some embodiments, the resonant frequency corresponding to the sensor device without an equivalent resonant system can be in a higher frequency range. For example, in some embodiments, the resonant frequency corresponding to the sensor device without an equivalent resonant system is higher than 7000 Hz. In some embodiments, the resonant frequency corresponding to the sensor device without an equivalent resonant system is higher than 10000 Hz. In some embodiments, the resonant frequency corresponding to the sensor device without an equivalent resonant system is higher than 12000 Hz. Accordingly, the sensor device without an equivalent resonant system may have higher rigidity, which also provides the sensor device with higher impact resistance and reliability.

[0152] The frequency response curve 1020 includes a first (or third) resonance peak (not shown) and a second (or fourth) resonance peak 1021. In some embodiments, the frequency corresponding to the first (or third) resonance peak is close to or the same as the corresponding resonance frequency in the frequency response curve 1010. In some embodiments, the frequency response curve 1020 is similar to the frequency response curve 1010. Figure 9 Compared with the frequency response curve 920 in FIG, except that the first (or third) resonance peak is shifted to the right, the frequency corresponding to the second (or fourth) resonance peak 1021 is substantially the same as that of FIG. Figure 9 The frequency range corresponding to the second (or fourth) resonance peak 922 is the same or similar.

[0153] In some embodiments, within a desired frequency range (e.g., within 2000 Hz, within 3000 Hz, within 5000 Hz, etc.), the difference between the maximum and minimum sensitivity values in frequency response curve 1020 should be maintained within a certain range to ensure a stable frequency response of sensing device 500 or 700. In some embodiments, within the desired frequency range, the difference between the maximum and minimum sensitivity values is no greater than 40 dBV, and the ratio of the sensitivity difference to the maximum value is no greater than 0.3. In some embodiments, within the desired frequency range, the difference between the maximum and minimum sensitivity values is no greater than 10 dBV, and the ratio of the sensitivity difference to the maximum value is no greater than 0.1.

[0154] In some embodiments, the difference in resonant frequency between the first (or third) resonant peak and the second (or fourth) resonant peak 1021 (the frequency of the first (or third) resonant peak is represented by f0 (close to resonant peak 1011), the frequency of the second (or fourth) resonant peak 1021 is represented by f1, and the difference in resonant frequency between the two resonant peaks is represented by frequency difference Δf2) is within a certain range. In some embodiments, the frequency difference Δf2 is within a range of 1000-8000 Hz, and the ratio of the frequency difference Δf2 to f0 is within a range of 0.2-0.8. In some embodiments, the frequency difference Δf2 is within a range of 3000-4000 Hz, and the ratio of the frequency difference Δf2 to f0 is within a range of 0.3-0.4.

[0155] Compared to frequency response curve 1010, frequency response curve 1020 exhibits a higher and more stable sensitivity improvement (i.e., difference, represented by ΔV3) within the frequency range within the resonant frequency f1 corresponding to the second (or fourth) resonant peak 1021. In some embodiments, the improvement ΔV3 is within a range of 10 dBV to 60 dBV. In some embodiments, the improvement ΔV3 is within a range of 20 dBV to 40 dBV. In some embodiments, the improvement ΔV3 is within a range of 30 dBV to 40 dBV.

[0156] For sensor device 700, in some embodiments, the frequency corresponding to fourth resonance peak 1021 (i.e., the fourth resonance frequency) is a mid-low frequency, and the frequency corresponding to the third resonance peak (i.e., the third resonance frequency) is a mid-high frequency. In some embodiments, the difference between the minimum sensitivity of frequency response curve 1020 within the frequency range up to resonance frequency f1 and the peak value of the fourth resonance peak is no greater than 30 dBV, and the ratio thereof is no greater than 0.2. In some embodiments, the difference between the minimum sensitivity of frequency response curve 920 within the frequency range up to resonance frequency f1 and the peak value of the fourth resonance peak is no greater than 10 dBV, and the ratio thereof is no greater than 0.1.

[0157] In some embodiments, the frequency response of the sensing device 500 or 700 can be described by one or more of the parameters related to the curve 1020, such as the peak value and frequency of the primary resonance peak, the peak value and frequency of the secondary resonance peak 1021, the Q value, Δf2, ΔV3, the ratio of Δf2 to f0, the ratio of the maximum sensitivity to the minimum sensitivity within the desired frequency range, the first-order coefficient, the second-order coefficient, the third-order coefficient of the equation determined by fitting the frequency response curve, etc. In some embodiments, the frequency response of the sensing device 500 or 700 can be related to the properties of the filled liquid and / or the parameters of the transducer unit. In some embodiments, to obtain the ideal output frequency response of the sensing device 500 or 700 (e.g., the frequency response curve 1020), the range of the parameters affecting the frequency response listed above (also known as frequency response influencing factors, including the properties of the filled liquid and / or the parameters of the transducer unit) can be determined by computer simulation, phantom experiments, etc., and then compared with the range of the parameters affecting the frequency response. Figure 9 The methods described are the same or similar and will not be repeated here.

[0158] Figure 11 is a schematic diagram of a sensing device to be filled with liquid according to some embodiments of this specification.

[0159] like Figure 11 As shown, the sensing device 1100 includes a housing 1110, a transducer unit 1120, a processor 1130 and a PCB 1140. At least one through-hole may be provided on the upper surface of the housing 1110 of the sensing device 1100. The through-hole may connect the outside world and the accommodating cavity of the sensing device 1100. Liquid may be injected into the accommodating cavity of the sensing device 1100 through the at least one through-hole. In some embodiments, the through-hole may include a liquid injection hole 1111 and an exhaust hole 1112. Liquid may be injected into the accommodating cavity of the sensing device 1100 through the liquid injection hole 1111. At the same time, the air in the accommodating cavity may be discharged through the exhaust hole 1112 to ensure that the liquid can completely fill the accommodating cavity, the transducer unit 1120 and the processor 1130 are immersed in the liquid, and there are no bubbles. Optionally, the through-hole may only include the liquid injection hole 1111. In a vacuum environment, liquid is injected into the accommodating cavity of the sensor device 1100 through the liquid injection hole 1111, and the liquid can completely fill the accommodating cavity. The transducer unit 1120 and the processor 1130 are immersed in the liquid without bubbles.

[0160] In some embodiments, when sensing device 1100 is filled with liquid but contains no bubbles, sensing device 1100 is similar to sensing device 500. Due to the viscosity of the liquid, it can increase the damping of transducer unit 1120, thereby reducing the Q value of the resonant peak of sensing device 1100 (also known as the first resonant peak, i.e., the peak corresponding to the natural resonant frequency of transducer unit 1120). Furthermore, liquid is not easily compressed and may exhibit excessive stiffness and overdamping. In this case, the additional resonant peak (i.e., the second resonant peak) formed by the addition of liquid has a higher frequency and may be closer to the first resonant peak of sensing device 1100. The first and second resonant peaks may at least partially overlap, resulting in a lower flatness of the frequency response curve.

[0161] In some embodiments, by adjusting the viscosity or density of the liquid filled in the sensor device 1100 (for example, by selecting liquids of different densities and viscosities or adding specific agents to adjust the density or viscosity), the Q value of the resonance peak corresponding to the transducer unit 1120 in the sensor device 1100 can be adjusted within a certain range. For example, within a certain range, the greater the kinematic viscosity of the liquid, the smaller the Q value. In some embodiments, the density of the liquid can be 0.6-2 kg / m 3 In some embodiments, the density of the liquid may be 0.8-1.0 kg / m 3 In some embodiments, the density of the liquid may be 0.93-0.95 kg / m 3 .

[0162] In some embodiments, the kinematic viscosity of the liquid may be 0.1-5000 cSt. In some embodiments, the kinematic viscosity of the liquid may be 50-200 cSt.

[0163] In some embodiments, the liquid filling the accommodating cavity may include bubbles. The bubbles have a certain volume. For example, the ratio of the bubbles to the volume of the accommodating cavity of the sensing device 1100 may be any value between 5% and 95%. The number of bubbles may be 1, 2, 3, 4, or more, and is not specifically limited in this specification.

[0164] The bubbles can be located at different locations within the sensing device 1100. Taking a bone conduction microphone as an example, the chamber can be divided into a front chamber and a rear chamber, with the plane of the cantilever beam serving as the dividing plane. In some embodiments, the bubbles can be located within the front chamber. For example, the bubbles can be located in the front chamber away from the cantilever beam, near the cantilever beam, or attached to the cantilever beam. In some embodiments, the bubbles can be located in the rear chamber. In other embodiments, the bubbles can exist in both the front and rear chambers.

[0165] Bubbles can be formed by air that has not been discharged from the accommodating cavity. For example, when the amount of filling liquid is less than the volume of the accommodating cavity, bubbles will remain in the accommodating cavity. In some embodiments, bubbles can be formed by encapsulating gas in an airbag. For example, the airbag can be a film-like material (such as polyester film, nylon film, plastic film, composite film, etc.) itself or a closed capsule formed with a component inside the housing or the sensing device 1100, and the closed capsule is filled with gas. The size and shape of the airbag can be set according to the volume of the desired bubble, the volume and shape of the accommodating cavity, and / or the position of the airbag. In some embodiments, bubbles can also be formed by arranging a hydrophobic material on the inner surface of the accommodating cavity or on the surface of a component inside it. The bubbles adhere to the surface of the hydrophobic material. For example, a super-hydrophobic coating can be provided on a partial area of the inner surface of the accommodating cavity or a partial surface of a component inside it. Super-hydrophobic coating can be by fluorine-containing polymer, for example, polytetrafluoroethylene, fluorinated ethylene propylene copolymer, the copolymer of ethylene and tetrafluoroethylene, tetrafluoroethylene and perfluoroalkoxy vinyl ether copolymer etc., or polymer melt polymer, for example polyolefin, polycarbonate, polyamide, polyacrylonitrile, polyester, fluorine-free acrylate, molten paraffin etc. are made through specific process etc..The gas in bubble can be air, oxygen, nitrogen, inert gas etc. or its arbitrary combination.In certain embodiments, due to gas in vibration process, there is certain elastic property in gas, therefore, the equivalent stiffness of bubble (or gas) can be changed by changing the air pressure in bubble, thereby changing the performance of second resonant system.

[0166] After the sensor device 1100 is filled with liquid and bubbles, it can be similar to the sensor device 700. Because bubbles are easily compressible and have low rigidity, the combined rigidity of the liquid and bubbles is low. Consequently, the resonant frequency (also called the fourth resonant frequency) corresponding to the resonant peak (also called the fourth resonant peak) of the second resonant system formed by the liquid and bubbles in the sensor device 1100 is low, and the difference between this and the natural resonant frequency (also called the third resonant frequency) of the transducer unit 1120 of the sensor device 1100 is large. This effectively controls the final output performance of the sensor device 1100, thereby significantly improving the overall sensitivity of the sensor device 1100, resulting in a flatter frequency response curve and a wider effective bandwidth (satisfying the flat frequency response condition). In some embodiments, by adjusting the ratio of the bubble volume to the liquid volume in the sensor device 1100, the position of the fourth resonant peak can be adjusted, so that the third and fourth resonant peaks fall within a certain frequency band. This can optimize the frequency response curve of the sensor device 1100 and make it relatively flat.

[0167] After the liquid or liquid and bubbles fill the accommodating cavity (e.g., the front cavity), the through hole on the upper surface of the housing 1110 will be blocked. In some embodiments, a sealing member can be used to seal the through hole. The sealing member can include, for example, a plug, a screw, or adhesive tape. In some embodiments, the through hole is a circular threaded hole. The sealing member can seal the at least one through hole by means of a threaded connection.

[0168] Figure 12 is a schematic diagram of an exemplary liquid-filled sensing device according to some embodiments of the present specification.

[0169] like Figure 12 As shown, the sensing device 1200 can be a liquid-filled bone conduction microphone, including a shell 1210, a transducer unit 1220, a processor 1230 and a PCB substrate 1240. The accommodating cavity of the shell 1210 is filled with liquid 1250. The transducer unit 1220 includes a piezoelectric layer 1221. The transducer unit 1220 and the processor 1230 are connected by a lead 1260. In some embodiments, the structure and internal components of the sensing device 1200 are the same as or similar to those of the sensing device 500 and are not described here. At least one through hole (not shown in the figure) is provided on the metal shell of the sensing device 1200. Through the at least one through hole, the liquid 1250 (for example, silicone oil) can be filled into the cavity inside the sensing device 1200.

[0170] In some embodiments, the housing 1210 may be made of metal, plastic, glass, etc. In some embodiments, the housing 1210 may be made of a transparent material. Through the transparent housing, it is possible to observe whether the internal cavity of the sensor device 1200 is filled with liquid, whether there are bubbles, etc.

[0171] It should be noted that the above description of the sensor device 1200 is merely illustrative and does not limit this specification to the embodiments described. It is understood that those skilled in the art, after understanding the principles of the system, may arbitrarily combine its structures and modules, or form subsystems that connect to other modules without departing from these principles. For example, the first resonant system 530 or the second resonant system 740 in the form of a liquid or a liquid and bubbles may also be incorporated into an audio output device, such as a speaker, to improve the speaker's frequency response.

[0172] Figure 13 1 is a frequency response curve of the sensing device before and after being partially filled with liquid according to some embodiments of the present application.

[0173] like Figure 13As shown, frequency response curve 1310 represents the frequency response curve of a sensor device (e.g., sensor device 1200) filled with liquid (e.g., silicone oil with a kinematic viscosity of 0.65 cSt). Frequency response curve 1320 represents the frequency response curve of the sensor device after the liquid is removed from the sensor device, leaving only a portion of the liquid (e.g., an oil film). In some embodiments, the front chamber of the sensor device is completely filled with liquid, while the rear chamber is partially filled with liquid. The volume of the rear chamber filled with liquid can range from 1% to 90% of the volume of the front chamber.

[0174] It can be seen that when the sensor is filled with liquid (for example, the front chamber is fully filled with liquid and the rear chamber is partially filled with liquid), compared to when only some liquid remains (for example, an oil film is present), the sensitivity of the sensor device is significantly and stably improved in the low-frequency, mid-low-frequency, or mid-high frequency band (for example, within the frequency band less than 7000Hz, 5000Hz, 3000Hz, 1000Hz, or 500Hz). In some embodiments, the sensitivity improvement can reach 10-50dBV. In some embodiments, the sensitivity improvement can reach 10-30dBV. In some embodiments, the sensitivity improvement can reach 20-30dBV.

[0175] Although the sensitivity of the sensor device is greatly improved after being filled with liquid, it is in an over-damped or over-rigid state, with excessive suppression near the mid-frequency, causing the frequency response curve to drop rapidly, and the peak at the natural resonant frequency of the transducer unit in the sensor device is suppressed. In order to avoid excessive suppression of the mid-frequency due to over-damping, a certain volume of bubbles can be retained in the shell. The second resonant system 740 formed by the liquid and bubbles will have less stiffness or damping than the first resonant system 530 filled with liquid (for example, silicone oil), which can reduce the suppression of the mid-frequency.

[0176] Figure 14 This is a frequency response curve of a sensor device with a small-sized accommodating cavity before and after being filled with liquid according to some embodiments of this specification.

[0177] The sensing device (e.g., sensing device 1200) is formed by filling the receiving cavity of the sensing device (e.g., sensing device 1100) with liquid. In this embodiment, the receiving cavity of the sensing device is a small-sized receiving cavity. In some embodiments, the length, width, and height of the receiving cavity of the sensing device are 0.5-10 mm, 0.5-10 mm, and 0.3-10 mm, respectively. In some embodiments, the length, width, and height of the receiving cavity of the sensing device are 3-10 mm, 2-8 mm, and 0.8-5 mm, respectively.

[0178] For example, in this embodiment, the accommodating cavity of the sensor device has a relatively small size: 3.76mm×2.95mm×0.8-0.85mm. Figure 14As shown, curve 1410 is the frequency response curve of the sensor device when the accommodating chamber is not filled with liquid. Curve 1420 is the frequency response curve of the sensor device when the accommodating chamber is fully filled with liquid (e.g., silicone oil with a kinematic viscosity of 0.65 cSt). Curve 1430 is the frequency response curve of the sensor device when only the rear chamber is partially filled with liquid. Curve 1440 is the frequency response curve of the sensor device when only the oil film remains on the surface of the transducer element (e.g., cantilever beam).

[0179] Combined with curves 1410-1440, it can be seen that for a small-sized accommodating cavity, completely filling it with liquid (corresponding to curve 1420) does not increase the sensitivity of the sensor device. When the small-sized accommodating cavity is filled with liquid, the additional resonant frequency of the liquid is very high and cannot resonate before the natural resonant frequency (first or third resonant frequency) of the transducer unit. At the same time, the introduction of liquid also leads to an increase in additional stiffness and damping, suppressing the vibration of the transducer unit and reducing the output of the sensor device. When only some liquid remains in the rear cavity (corresponding to curve 1430), it can be considered that a large bubble has been introduced into the accommodating cavity of the sensor device. Because bubbles are easily compressible and have low stiffness, the combined stiffness of the liquid and bubbles is relatively low. The resonant frequency (also called the fourth resonant frequency) corresponding to the resonant peak (also called the fourth resonant peak) of the second resonant system formed by the liquid and bubbles in the sensor device is low, and the difference between it and the natural resonant frequency (also called the third resonant frequency) of the transducer unit of the sensor device is relatively large. Therefore, the sensitivity of the sensor device is significantly improved over a wider frequency band.

[0180] Figure 15 These are frequency response curves of a sensing device with a large-sized accommodating cavity shown in some embodiments of this specification when the cavity is not filled with liquid, partially filled with liquid, or when an oil film exists in the accommodating cavity.

[0181] A sensing device (e.g., sensing device 1200) is formed after the accommodating cavity of the sensing device (e.g., sensing device 1100) is filled with liquid. In this embodiment, the accommodating cavity of the sensing device is a large-sized accommodating cavity. In some embodiments, the length, width, and height of the accommodating cavity of the sensing device are 1-30 mm, 1-30 mm, and 0.5-30 mm, respectively. In some embodiments, the length, width, and height of the accommodating cavity of the sensing device are 8-10 mm, 5-10 mm, and 1-5 mm, respectively. Optionally, the accommodating cavity of the sensing device has a larger size. In some embodiments, the length, width, and height of the accommodating cavity of the sensing device are 10-200 mm, 10-100 mm, and 10-100 mm, respectively. In some embodiments, the length, width, and height of the accommodating cavity of the sensing device are 10-50 mm, 10-30 mm, and 10-30 mm, respectively. Exemplarily, in this embodiment, the accommodating cavity of the sensor device has a relatively large size: 10 mm×7 mm×1-4 mm.

[0182] As previously mentioned, a sensor device with silicone oil in a small cavity can be overdamped or overstiff, resulting in excessive mid-frequency suppression, a rapid drop in the frequency response curve, and complete suppression of the resonant peak at the resonant frequency of a sensor device without liquid. Increasing the cavity size can improve the sensor's mid-frequency output, reduce the liquid's suppression of the sensor's mid-frequency response, and flatten the sensor's frequency response curve.

[0183] like Figure 15 As shown, curves 1510 and 1520 respectively represent the frequency response curves of a large-sized accommodating cavity not filled with liquid and partially filled with liquid (for example, silicone oil with a kinematic viscosity of 0.65 cst) or an oil film in the accommodating cavity.

[0184] It can be seen that when the chamber is partially filled with liquid or an oil film exists within the chamber (corresponding to curve 1520), the frequency response sensitivity of the sensor device is improved compared to when the chamber is not filled with liquid (corresponding to curve 1510). In some embodiments, the improvement is 10-40 dBV. In some embodiments, the improvement is 10-20 dBV. In some embodiments, the improvement is approximately 15 dBV.

[0185] Figure 16 is a schematic diagram of a sensing device filled with liquid and bubbles according to some embodiments of the present specification.

[0186] Since the inside of the bubble is gas (such as air), its stiffness, mass, and damping are quite different from those of the liquid. Therefore, by controlling the size and position of the introduced bubble, the second resonant system 740 (i.e., the additional spring-mass-damping system) of the sensing device (e.g., sensing device 1200) can be adjusted, thereby effectively controlling the final output performance of the sensing device, making the frequency response relatively flat (e.g., peak-to-valley fluctuation less than 5dBV, 10dBV, 15dBV, etc.), and the effective bandwidth (satisfying the flat frequency response condition) covering a certain range (e.g., 20Hz-8K Hz), while the overall sensitivity is improved to a certain extent (e.g., 10-50dBV).

[0187] In this embodiment, the accommodating cavity of the sensor device is a large-sized accommodating cavity. In some embodiments, the accommodating cavity size can be 10mm×7mm×1-4mm. Exemplarily, the accommodating cavity size of the sensor device is 10mm×7mm×1mm.

[0188] In some embodiments, the bubbles may have different sizes and the positions of the bubbles in the receiving chamber of the sensor device may also be different. Figure 16As shown, the bubbles can be small bubbles (for example, the volume ratio of the bubbles to the accommodating cavity is 10% or less), medium or large bubbles (for example, the volume ratio of the bubbles to the accommodating cavity is 10% to 90%), etc. The bubbles can be located in the front cavity of the accommodating cavity of the sensing device (away from the cantilever beam, close to or attached to the cantilever beam, etc.), the rear cavity, or both the front cavity and the rear cavity. For more details about the different positions of the bubbles, please refer to the description elsewhere in this application specification, such as Figures 18A-18D and its description.

[0189] Just as an example, Figure 16 As shown, after the accommodating cavity of the sensing device 1610 is filled with liquid, there is a small bubble in the corner, and the volume of the bubble is about 2%-10% of the volume of the liquid. There are no bubbles near the transducer unit (for example, the cantilever beam). After the accommodating cavity of the sensing device 1620 is filled with liquid, the volume of the bubble is about 10%-20% of the volume of the liquid, and the transducer unit area is not covered. At this time, the transducer unit is completely soaked in silicone oil. After the accommodating cavity of the sensing device 1630 is filled with liquid, the volume of the bubble is about 20%-50% of the volume of the liquid, and the transducer unit area is not covered. At this time, the transducer unit is completely soaked in silicone oil. After the accommodating cavity of the sensing device 1640 is filled with liquid, the volume of the bubble is about 50%-90% of the volume of the liquid, covering the transducer unit area. At this time, the transducer unit is not completely soaked in silicone oil.

[0190] Figure 17 1 is a frequency response curve of a sensor device containing bubbles of different sizes in a liquid filled in a chamber according to some embodiments of this specification.

[0191] In this embodiment, the receiving cavity of the sensor device (e.g., sensor device 1200) is a large-sized receiving cavity. In some embodiments, the receiving cavity dimensions may be 10 mm × 7 mm × 1-4 mm. For example, the receiving cavity dimensions of each sensor device are 10 mm × 7 mm × 1 mm.

[0192] like Figure 17 As shown, curve 1710 represents the frequency response curve of the sensor device (e.g., sensor device 1100) that is not filled with silicone oil. Curve 1720 represents the frequency response curve of the sensor device (e.g., sensor device 1100) that is not filled with silicone oil. Figure 16 The frequency response curve of the sensor device for small bubbles is shown in FIG. Curve 1730 represents the frequency response curve of the sensor device for small bubbles. Figure 16 The frequency response curve of the sensor device for small and medium-sized bubbles is shown in FIG. Curve 1740 represents the frequency response curve of the sensor device for small and medium-sized bubbles. Figure 16 The frequency response curve of the sensing device for a medium-sized bubble is shown.

[0193] As can be seen from curves 1710-1740, when the bubbles do not cover the transducer unit (e.g., a piezoelectric transducer), the sensitivity of the sensor device increases as the bubble volume increases. For example, compared to a sensor device containing small bubbles (corresponding to curve 1720), a sensor device containing small and medium-sized bubbles (corresponding to curve 1730) has a sensitivity improvement of approximately 5-30 dBV in low-frequency, mid-low-frequency, or mid-high frequency bands (e.g., within the frequency bands below 7000 Hz, 5000 Hz, 3000 Hz, 1000 Hz, or 500 Hz). In some embodiments, low-frequency roll-off occurs in even lower frequency bands (e.g., within the frequency bands below 5000 Hz, below 3000 Hz, 500 Hz, or 200 Hz). Compared with the sensor device containing small and medium-sized bubbles (corresponding curve 1730), the sensor device containing medium-sized bubbles (corresponding curve 1740) has a sensitivity improvement of approximately 5-30dBV in the frequency band before low frequency or medium-low frequency or medium-high frequency (for example, within the frequency band less than 7000Hz, 5000Hz, 3000Hz, 1000Hz or 500Hz).

[0194] Figures 18A-18D Schematic diagram of a sensing device for bubbles in a filling liquid at different positions according to some embodiments of this specification.

[0195] like Figure 18A Taking the bone conduction microphone 1810 as an example, the transducer unit 1812 can include a cantilever beam. The housing of the bone conduction microphone 1810 can be divided into a front chamber 1813 and a rear chamber 1814, using the plane where the transducer unit 1812 is located as a dividing plane. In some embodiments, the space formed by the base 1811 and the plane where the transducer unit 1812 is located can form the rear chamber 1814. In some embodiments, the space formed by the base 1811, the plane where the transducer unit 1812 is located, and a portion of the housing of the bone conduction microphone 1810 can form the rear chamber 1814. The front chamber 1813 can be the space within the housing of the bone conduction microphone 1810 excluding the rear chamber 1814.

[0196] Figure 18A The front chamber 1813 and the rear chamber 1814 are filled with liquid 1815. Bubbles 1816 are located in the front chamber 1813, away from the transducer unit 1812. Bubbles 1816 can be located in the middle or in a corner of the front chamber 1813. Bubbles 1816 can be small (e.g., the volume ratio of the bubble to the front chamber is 10% or less), medium, or large (e.g., the volume ratio of the bubble to the front chamber is 10% to 90%), etc.

[0197] Figure 18B The structure and Figure 18AThe base 1821 and the transducer unit 1822 form a rear cavity 1824. The space in the housing cavity of the bone conduction microphone 1820 other than the rear cavity 1824 is a front cavity 1823. Both the front cavity 1823 and the rear cavity 1824 are filled with liquid 1825. Bubbles 1826 are located in the front cavity 1823 and are attached to or close to the transducer unit 1822. Bubbles 1826 can be small bubbles (for example, the volume ratio of the bubbles to the front cavity is 10% or less), medium or large bubbles (for example, the volume ratio of the bubbles to the front cavity is 10% to 90%), etc.

[0198] Figure 18C The structure and Figure 18A or Figure 18B Similar. The base 1831 and the transducer unit 1832 form a rear cavity 1834. The space in the accommodating cavity of the bone conduction microphone 1830 except the rear cavity 1834 is the front cavity 1833. Both the front cavity 1833 and the rear cavity 1834 are filled with liquid 1835. The bubble 1836 is located in the rear cavity 1834. The bubble 1836 can be located in the middle or corner of the rear cavity 1834. The bubble 1836 can be a small bubble (for example, the volume ratio of the bubble to the rear cavity is 10% or less), a medium or large bubble (for example, the volume ratio of the bubble to the rear cavity is 10% to 90%), etc.

[0199] Figure 18D The structure and Figure 18A 、 Figure 18B or Figure 18C Similarly, the base 1841 and the transducer unit 1842 form a rear cavity. In this case, only the transducer unit 1842 in the cavity of the bone conduction microphone 1840 contains liquid 1843 (e.g., an oil film). This suggests that the cavity of the bone conduction microphone 1840 contains large bubbles (e.g., a bubble-to-cavity volume ratio exceeding 90%), while the cavity is filled with very little liquid.

[0200] It should be noted that the above description of the sensor device is only an example description and does not limit this specification to the scope of the embodiments. It is understandable that for those skilled in the art, after understanding the principle of the system, it is possible to arbitrarily adjust its structure and composition without deviating from this principle. Such variations are all within the scope of protection of this application. For example, 18A to 18D The transducer unit may also include a diaphragm (such as Figure 32A The piezoelectric film 32211A shown in FIG. 3 is a piezoelectric film 32211A shown in FIG. 3 ). The plane where the diaphragm is located can separate the accommodating cavity into a front cavity and a rear cavity. For example, 18A to 18D The transducer unit can also include a cantilever beam and a diaphragm (such as Figure 35B The piezoelectric beam 35211 and the second membrane structure 35213 are shown).

[0201] Figure 19 These are frequency response curves of bubbles in a filling liquid at different positions within a chamber of a sensor device according to some embodiments of this specification.

[0202] When the liquid filled in the accommodating chamber of the sensor device contains bubbles of different sizes, the output performance of the corresponding spring (Km3, Km4)-mass (Mm4)-damping (Rm3, Rm4) systems is also different.

[0203] like Figure 19 As shown, curve 1910 represents the frequency response curve of a sensing device (e.g., sensing device 1100) whose accommodating chamber is not filled with liquid. Curve 1920 represents the frequency response curve of a sensing device whose front chamber contains liquid (e.g., silicone oil) and large bubbles, and the bubbles are far away from the transducer unit, while the rear chamber contains liquid. Curve 1930 represents the frequency response curve of a sensing device whose front chamber contains air and the rear chamber contains liquid. Curve 1940 represents the frequency response curve of a sensing device whose front and rear chambers are both filled with liquid, and bubbles are present in the rear chamber. Curve 1950 represents the frequency response curve of a sensing device whose transducer unit is only covered by a liquid film.

[0204] From the curves 1910-1950, it can be seen that when bubbles are introduced, regardless of whether the bubbles are located in the front cavity, the rear cavity, or whether they are in contact with the transducer unit, the sensitivity of the sensing device can be improved to a certain extent (e.g., 10-60dBV, 10-40dBV, 15-40dBV, etc.) in the low frequency, mid-low frequency, or mid-high frequency band (e.g., within the frequency band less than 7000Hz, 5000Hz, 3000Hz, 1000Hz, or 500Hz). The magnitude of the improvement is also related to the size and / or position of the bubbles. For example, from the curves 1920 and 1930, it can be seen that when the bubbles are located in the front cavity and are not in contact with the transducer device, the sensitivity gradually increases with the increase of bubbles.

[0205] In addition to the gain in sensitivity at low, medium, and medium-high frequencies, different bubble-liquid combinations also have different effects on higher frequencies. For example, when bubbles are present in the rear chamber, the higher frequencies are less suppressed.

[0206] Figure 20 1 is a frequency response curve before and after the sensing device is filled with liquid according to some embodiments of this specification.

[0207] like Figure 20 As shown, curves 2010 and 2020 are frequency response curves of a sensor device not filled with liquid (eg, sensor device 1100) and a sensor device filled with liquid with bubbles in the back cavity, respectively.

[0208] Combining curves 2010 and 2020, it can be seen that the liquid-filled sensing device has a resonance peak in the frequency band of 2000-20000 Hz. Relatively speaking, the sensing device filled with liquid and introducing bubbles in the back cavity (for example, small bubbles (for example, the volume ratio of bubbles to the back cavity is 10% or less), medium or large bubbles (for example, the volume ratio of bubbles to the back cavity is 10% to 90%), etc.) has a gain of about 10-40 dBV in the frequency band before low frequency or medium-low frequency or medium-high frequency (for example, within the frequency band less than 7000 Hz, 5000 Hz, 3000 Hz, 1000 Hz or 500 Hz). In some embodiments, the gain in the low frequency band is 20-25 dBV. The spring (K) composed of the combination of bubbles and liquid m3，4 )-Mass(M m4) - Damping (R m3，4 ) system forms resonance in the low frequency band, which greatly increases the gain of the sensor device in this band. In addition, due to the spring (K m3，4) -Mass (M m4 )-damping(R m3，4 The additional damping and stiffness of the system have a suppressive effect on the vibration of the sensor device, and the Q value of the resonance peak (for example, the first or third resonance peak) at the resonance frequency of the corresponding sensor device (here is the intermediate frequency) is significantly reduced. In addition, by adjusting the combination of bubbles and liquid, the additional spring (K m3，4 )-Mass(M m4 )-damping(R m3，4) The characteristics of the sensor device cause the resonant frequency (for example, the first or third resonant frequency) to move forward or backward.

[0209] In some embodiments, bubbles of a certain size are set in the front cavity and the rear cavity, so that a larger gain can be achieved in the low-frequency part, and the intermediate frequency can suppress the Q value of the resonance peak (first or third resonance peak) of the transducer unit in the sensing device without suppressing the sensitivity of other areas outside the resonance peak area.

[0210] Figure 21 is a schematic diagram of an exemplary sensing device including droplets according to some embodiments of the present specification.

[0211] like Figure 21 As shown, taking a bone conduction microphone as an example, the structure of the sensor device 2100 is similar to Figures 18A-18CThe structure of the bone conduction microphones 1810-1830 in the sensor device 2100 is shown. The sensor device 2100 includes a shell 2110, a transducer unit 2120, a droplet 2130, and a substrate 2140. The droplet 2130 is provided in the accommodating cavity of the shell 2110. The substrate 2140 and the transducer unit 2120 constitute a rear cavity 2111. The space in the accommodating cavity in the shell 2110 of the sensor device 2100 other than the rear cavity 2111 is the front cavity 2112. The droplet 2130 can be located at any position on the surface of the transducer unit 2120, so that at least a portion of the transducer unit 2120 is connected to the shell 2110 through the droplet 2130. The droplet 2130 can be equivalent to a spring-mass-damper system (for example, the first resonant system 530 or the second resonant system 740). The droplet 2130 can adjust the vibration characteristics of the transducer unit 2120 so that its original resonant frequency (for example, the first or third resonant frequency) changes, while the Q value is in an appropriate range. Moreover, due to the existence of a newly added resonant peak (for example, the second or fourth resonant peak), the sensing device 2100 has a higher sensitivity.

[0212] Exemplarily, a droplet 2130 is present in the front chamber 2112. The droplet 2130 is located between the transducer unit 2120 and the housing 2110, with its upper and lower portions connected to the transducer unit 2120 and the housing 2110, respectively. In some embodiments, the volume of the droplet 2130 may be 1% to 80% of the volume of the front chamber. In some embodiments, the volume of the droplet 2130 may be 20% to 30% of the volume of the front chamber. Alternatively, the droplet 2130 may be located in the rear chamber 2111. In some embodiments, the volume of the droplet 2130 may be 5% to 80% of the volume of the rear chamber. In some embodiments, the volume of the droplet 2130 may be 20% to 30% of the volume of the rear chamber.

[0213] The droplets 2130 may be formed by directly adding the droplets into the accommodating cavity (eg, the front cavity or the rear cavity), or by other methods, such as film wrapping.

[0214] Figure 22 is a schematic diagram of an exemplary sensing device including droplets according to some embodiments of the present specification.

[0215] Figure 22 The structure of the sensor device 2200 is Figure 21 Similar. Figure 22As shown, the sensing device 2200 includes a shell 2210, a transducer unit 2220, a droplet 2230, and a substrate 2240. The housing cavity of the shell 2210 is provided with the droplet 2230. The substrate 2240 and the transducer unit 2220 constitute a rear cavity 2211. The space other than the rear cavity 2211 in the housing cavity within the shell 2210 of the sensing device 2200 is the front cavity 2212. The droplet 2230 can be located at any position on the surface of the transducer unit 2220, so that at least a portion of the transducer unit 2220 is connected to the shell 2210. In this embodiment, the droplet 2230 includes bubbles 2250. The bubbles in the droplet 2230 can be formed by adding gas to the droplet or other methods (for example, film wrapping, etc.). In some embodiments, the droplet 2230 forms a hollow droplet due to the presence of the bubble 2250. In some embodiments, the size and position of the hollow droplet are the same as or similar to those of the droplet 2130, and will not be further described here. The droplet 2230 and the bubble 2250 can be equivalent to a spring-mass-damper system (e.g., the first resonant system 530 or the second resonant system 740). By adding the bubble 2250, the stiffness and / or damping of the introduced spring-mass-damper system can be adjusted over a wider range, allowing the newly added resonant frequency (e.g., the second or fourth resonant frequency) and the device Q value to be adjusted over a wider range.

[0216] In some embodiments, a gap (e.g., a slit, slot, hole, etc.) exists between the transducer unit (e.g., a cantilever beam, a suspended membrane, etc.) and the housing of the sensing device. In some embodiments, an additional resonant system (e.g., a first resonant system 530 or a second resonant system 740) of the sensing device can be disposed in the gap. The additional resonant system can adjust the original vibration characteristics of the transducer unit 2220, causing the original resonant frequency (e.g., the first or third resonant frequency) to change while maintaining the Q value within an appropriate range. A new resonant system can also be introduced, and the presence of a newly added resonant peak (e.g., the second or fourth resonant peak) can provide the sensing device with higher sensitivity.

[0217] Figure 23A is a schematic diagram of an exemplary sensing device including a liquid film according to some embodiments of the present specification.

[0218] Figure 23A The structure of the sensor device 2300 is Figure 21 and 22 Similar. Figure 23AAs shown, the sensing device 2300 includes a housing 2310, a transducer unit 2320, a liquid film 2330, and a substrate 2340. The substrate 2340 and the transducer unit 2320 form a rear cavity 2311. The space within the accommodating cavity within the housing 2310 of the sensing device 2300, excluding the rear cavity 2311, is a front cavity 2312. A gap exists between the transducer unit 2320 and the housing 2310. The liquid film 2330 can be located within the gap between the transducer unit 2320 and the housing 2310, such that at least a portion of the transducer unit 2320 is connected to the housing 2310. In some embodiments, the thickness of the liquid film 2330 can be less than, equal to, or greater than the thickness of the transducer unit 2320.

[0219] Figure 23B is a schematic diagram of an exemplary sensing device including a liquid film according to some embodiments of the present specification.

[0220] Figure 23B The structure of the sensor device 2350 is Figure 21-22 and Figure 23A Similar. Figure 23B As shown, the sensing device 2350 includes a housing 2360, a transducer unit 2370, a liquid film 2380, and a substrate 2390. The substrate 2390 and the transducer unit 2370 form a rear cavity 2361. The space within the housing 2360 of the sensing device 2350, excluding the rear cavity 2361, is a front cavity 2362. There are multiple gaps between the transducer unit 2370 and the housing 2360. The liquid film 2380 can be located within the gaps within the transducer unit 2370 itself and the gaps between the transducer unit 2370 and the housing 2360, thereby connecting various parts of the transducer unit 2370 and at least a portion of the transducer unit 2370 to the housing 2360. In some embodiments, the thickness of the liquid film 2380 can be less than, equal to, or greater than the thickness of the transducer unit 2370.

[0221] Figure 24A is a schematic diagram of an exemplary sensing device including a liquid film according to some embodiments of the present specification.

[0222] Figure 24A The structure of the sensor device 2400 is Figure 21-22 and Figures 23A-23B Similar. Figure 24AAs shown, the sensor device 2400 includes a housing 2410, a transducer unit 2420, a liquid film 2430, and a substrate 2440. The substrate 2440 and the transducer unit 2420 form a rear cavity 2411. The space within the accommodating cavity within the housing 2410 of the sensor device 2400, excluding the rear cavity 2411, is a front cavity 2412. A gap exists between the transducer unit 2420 and the housing 2410. The liquid film 2430 can be located within the gap between the transducer unit 2420 and the housing 2410, so that at least a portion of the transducer unit 2420 is connected to the housing 2410. Furthermore, the liquid film 2430 also covers at least a portion of the surface of the transducer unit 2420. In this embodiment, the liquid film 2430 also covers the upper surface of the transducer unit 2420, thereby further improving the performance of the sensor device 2400.

[0223] Figure 24B is a schematic diagram of an exemplary sensing device including a liquid film according to some embodiments of the present specification.

[0224] Figure 24B The structure of the sensor device 2450 is Figure 21-22 、 Figures 23A-23B and Figure 24A Similar. Figure 24B As shown, the sensor device 2450 includes a housing 2460, a transducer unit 2470, a liquid film 2480, and a substrate 2490. The substrate 2490 and the transducer unit 2470 form a rear cavity 2461. The space within the accommodating cavity within the housing 2410 of the sensor device 2400, excluding the rear cavity 2461, is a front cavity 2462. A gap exists between the transducer unit 2470 and the housing 2460. The liquid film 2480 can be located within the gap between the transducer unit 2470 and the housing 2460, so that at least a portion of the transducer unit 2470 is connected to the housing 2460. Furthermore, the liquid film 2480 also covers at least a portion of the surface of the transducer unit 2470. In this embodiment, the liquid film 2480 also covers the upper and lower surfaces of the transducer unit 2470, thereby further improving the performance of the sensor device 2450.

[0225] Figure 25 Schematic diagram of the structure of the sensor device according to some embodiments of this specification. Figure 25 As shown, the sensing device 2500 may include a housing 2510 and a transducer unit 2520. The housing 2510 defines a housing cavity, and the transducer unit 2520 is disposed within the housing cavity. The transducer unit 2520 may include a vibration pickup structure 2521. The vibration pickup structure 2521 divides the housing cavity into a front cavity 2530 and a rear cavity 2540 located on opposite sides of the vibration pickup structure 2521.

[0226] The sensing device 2500 can generate deformation and / or displacement based on external signals, such as mechanical signals (such as pressure, mechanical vibration) and acoustic signals (such as sound waves). The deformation and / or displacement can be further converted into a target signal by the transducer unit 2520 of the sensing device 2500. The target signal can be an electrical signal, a mechanical signal (such as mechanical vibration), an acoustic signal (such as sound waves), an electrical signal, an optical signal, a thermal signal, etc. In some embodiments, the sensing device 2500 can be a microphone (such as a bone conduction microphone), a speaker (such as a bone conduction speaker), an accelerometer, a pressure sensor, a hydrophone, an energy harvester, a gyroscope, etc. A bone conduction microphone or a bone conduction speaker refers to a microphone or a speaker in which sound waves are conducted in a solid (such as bone) in the form of mechanical vibrations.

[0227] The shell 2510 can be a three-dimensional structure with an accommodating cavity (i.e., a hollow part). In some embodiments, the shell 2510 can be a regular shape or any irregular shape structure such as a cuboid, a sphere, a polygon, a prism, etc. In some embodiments, the shell 2510 can be made of metal (e.g., stainless steel, copper, etc.), plastic (e.g., polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS) and acrylonitrile-butadiene-styrene copolymer (ABS), etc.), composite materials (e.g., metal-based composite materials or non-metal-based composite materials), epoxy resin, phenolic, ceramic, polyimide, glass fiber (e.g., FR4-glass fiber), etc. or any combination thereof. In some embodiments, a flexible circuit board (FPC board) can be used as one side of the shell 2510 (e.g., Figure 25 The bottom wall of the middle shell 2510), the flexible circuit board can be used to install components such as the circuit and transducer unit of the sensing device, and the other side walls of the shell 2510 can be made of the materials listed above, which are not further limited here.

[0228] In some embodiments, the transducer unit 2520 may be a piezoelectric transducer. The transducer unit 2520 may include a substrate 2522 and a vibration pickup structure 2521. The vibration pickup structure 2521 may include a cantilever beam (e.g., a piezoelectric cantilever beam or a piezoelectric beam), a suspended membrane (e.g., a piezoelectric membrane), etc. supported by the substrate 2522.

[0229] In some embodiments, the substrate 2522 may be a structure having an open opening, with the vibration pickup structure 2521 located at and covering the open opening of the substrate 2522. The end of the substrate 2522 facing away from the vibration pickup structure 2521 is connected to the housing 2510, thereby dividing the accommodating cavity into a front cavity 2530 and a rear cavity 2540 located on opposite sides of the vibration pickup structure 2521. In some embodiments, the substrate 2522 may be made of a semiconductor material. Semiconductor materials may include, but are not limited to, silicon dioxide, silicon nitride, gallium nitride, zinc oxide, silicon carbide, and the like. In some embodiments, the vibration pickup structure 2521 may be physically connected to the substrate 2522. The “connection” mentioned in this specification can be understood as the connection between different parts of the same structure, or after preparing different parts or structures separately, the independent parts or structures are fixedly connected by welding, riveting, clamping, bolting, adhesive bonding, etc., or during the preparation process, the first part or structure is deposited on the second part or structure by physical deposition (for example, physical vapor deposition) or chemical deposition (for example, chemical vapor deposition). In some embodiments, the base 2522 can also be a cylindrical structure with two ends through, one end of the cylindrical structure is connected to the shell 2510, and the other end is connected to the vibration pickup structure 2521. For the specific structure of the vibration pickup structure 2521, please refer to Figure 30-36B and its description.

[0230] In some embodiments, the front cavity 2530 is filled with liquid, and the liquid is in contact with the vibration pickup structure 2521 and the base 2522. The liquid can transmit the vibration of the housing 2510 to the vibration pickup structure 2521. In some embodiments, the liquid can be selected to have safety properties (such as non-flammable and non-explosive) and stability properties (such as non-volatile and non-deteriorating at high temperatures). For example, the liquid may include oil (such as silicone oil, glycerin, castor oil, motor oil, lubricating oil, hydraulic oil (such as aviation hydraulic oil)), water (including pure water, other inorganic or organic aqueous solutions (such as salt water)), oil-water emulsion, or other liquids that meet its performance requirements, or a combination of one or more thereof.

[0231] In some embodiments, the sensing device 2500 may further include one or more conduit structures 2550, each of which connects the front chamber 2530 to the exterior of the housing 2510, with at least a portion of the liquid located within the conduit structures 2550. In some embodiments, the conduit structures 2550 may be independent structures relative to the housing 2510, and may be disposed through the sidewall of the housing 2510, or the sidewall of the housing 2510 may be provided with mounting holes, with the conduit structures 2550 connected to the mounting holes in the sidewall of the housing 2510. In some embodiments, the conduit structures 2550 may be a portion of the housing 2510, for example, the sidewall of the housing 2510 may extend toward the accommodating cavity to form one or more protrusions with channels connecting the accommodating cavity to the exterior of the housing 2510. In some embodiments, the cross-sectional shape of the conduit structures 2550 includes, but is not limited to, regular shapes such as circular, rectangular, elliptical, semicircular, polygonal, or any irregular shape. In some embodiments, the top pipe opening of the pipe structure 2550 can be flush with the side wall of the shell 2510, or protrude from the side wall of the shell 2510.

[0232] The shell 2510 of the sensing device 2500 vibrates when subjected to an external force. At this time, the shell 2510 drives the base 2522 to vibrate. Since the vibration pickup structure 2521 and the shell 2510 or the base 2522 have different properties, the vibration pickup structure 2521 and the base 2522 cannot maintain completely consistent movement, thereby generating relative motion, and further causing the vibration pickup structure 2521 to deform or displace. In some embodiments, the vibration pickup structure 2521 may include at least a piezoelectric layer. When the vibration pickup structure 2521 is deformed, the piezoelectric layer is subjected to deformation stress to generate an electric potential difference (voltage), thereby realizing the conversion of the vibration signal into an electrical signal. The processor 2523 can obtain the electrical signal from the vibration pickup structure 2521 and perform signal processing. Here, the processor 2523 and Figure 1The processor shown is similar. In some embodiments, each pipe structure 2550 connects the front cavity 2530 with the outside of the shell 2510. The outside of the shell 2510 can be an open space (for example, a space that is connected to the external environment), or it can be a closed or semi-closed space surrounded by another structure (for example, another part of the shell). In some embodiments, the outside of the shell 2510 can be filled with a medium different from the liquid in the front cavity 2530. For example, the outside of the shell 2510 can be filled with a gas (for example, air). In this case, one end of each pipe structure 2550 is located in the liquid in the front cavity 2530, and the other end is connected to the gas outside the shell 2510. The liquid and gas connected by each pipe structure 2550 can form a resonant system (the principle of which is similar to the first resonant system or the second resonant system described above), which can act on the transducer unit 2520 through the liquid in the front cavity 2530, thereby generating additional resonant peaks. Specifically, the vibration of the shell 2510 is transmitted to the pipe structure 2550, and the fluid area corresponding to the pipe structure 2550 (which may include the internal area of the pipe structure 2550 cavity and the vicinity of the end of the pipe structure 2550 extending into the liquid, i.e. Figure 25 The liquid in the area surrounded by the curve a shown in FIG. 25 squeezes the gas corresponding to the pipe structure 2550 (ie, Figure 25 The gas above the pipe structure 2550 shown in the figure generates vibration and acts on the transducer unit 2520, causing the transducer unit 2520 to generate an additional resonance peak. The resonance frequency corresponding to the resonance peak is lower than the first resonance frequency generated by the vibration pickup structure 2521, so that the response of the sensing device 2500 in the lower frequency band is greatly improved.

[0233] It should be noted that the above description of the sensor device 2500 is only an exemplary description and does not limit this specification to the scope of the embodiments cited. For example, the substrate may be a structure that is not limited to being independent of the shell. In some embodiments, the substrate may also be a part of the shell. For another example, the liquid may not only be filled in the front cavity. In some embodiments, the front cavity and the rear cavity may be filled with liquid. In some embodiments, the liquid may only be filled in the rear cavity, and the pipeline structure is correspondingly arranged in the rear cavity. For the specific structure of the pipeline structure arranged in the rear cavity, please refer to Figure 30 Description.

[0234] In order to enable the sensing device to have multiple resonance peaks and multiple resonance valleys, the sensing device 2500 may include multiple pipe structures. Preferably, these pipe structures may have different shapes or sizes.

[0235] In some embodiments, the volume of the cavity inside the pipe structure can be adjusted to adjust the mass of the liquid in the fluid region corresponding to the pipe structure, thereby adjusting the resonant frequency corresponding to the resonant system. In some embodiments, the cavity volumes of multiple pipe structures can be set to different values, and accordingly, the mass of the liquid in the fluid region corresponding to the pipe structure is different, so that the resonant frequencies of the resonant systems corresponding to the multiple pipe structures are different. Factors affecting the cavity volume include but are not limited to the cross-sectional area of the pipe structure (the cross-sectional area may be determined by the length, width or radius of the pipe structure cross section) and the height of the pipe structure. The cross-sectional area of the pipe structure refers to the area of the cross section perpendicular to its extension direction. In some embodiments, the cavity volume of the pipe structure can be adjusted by adjusting the cross-sectional area and / or the height of the pipe structure, thereby controlling the mass of the liquid in the cavity inside the pipe structure. Since the resonant frequencies of the resonant peaks corresponding to pipe structures with different cavity volumes are different, the multiple resonant systems corresponding to the multiple pipe structures (including the mass of the liquid in their fluid region and the gas above the liquid surface) can provide multiple additional resonant peaks for the sensing device. In addition, between the multiple resonant peaks, since the vibration direction of the liquid in the fluid region of the pipe structure changes, the resonant system corresponding to each pipe structure can provide an additional resonant valley for the sensing device, that is, the multiple pipe structures can provide multiple additional resonant valleys for the sensing device. That is to say, each pipe structure corresponds to an additional set of resonance peaks and resonance valleys in the resonance system. For details about the resonance peaks and resonance valleys, please refer to Figure 28 、 Figure 29A and Figure 29B and its related descriptions.

[0236] In some embodiments, multiple pipe structures may be provided on at least one side wall of the housing. For example, multiple pipe structures may be provided on the same side wall of the housing. For another example, multiple pipe structures may be provided on different side walls of the housing. In some embodiments, multiple pipe structures may be regularly distributed or irregularly distributed on the side wall of the housing in rows, columns, or rings. In some embodiments, the cross-sectional shapes of the multiple pipe structures may all be the same, may not all be the same, or may all be different. For example, the cross-sectional shapes of the multiple pipe structures may all be circular. For another example, the cross-sectional shapes of the multiple pipe structures may include any one of a rectangular, polygonal, circular, semicircular, and elliptical shape, or any combination thereof. Figure 26A Schematic diagram of multiple pipeline structures shown in some embodiments of this specification. Figure 26A As shown, multiple pipe structures 2650A are distributed in a row, and the cross-sectional shapes of the multiple pipe structures are different, namely rectangle, hexagon, ellipse, triangle, and pentagon. Figure 26B Schematic diagram of multiple pipeline structures shown in some embodiments of this specification. Figure 26BAs shown, the multiple pipe structures 2650B are distributed in a row, and the cross-sectional shapes of the multiple pipe structures 2650B are all circular.

[0237] Figure 27 is a mechanical equivalent schematic diagram of the sensing device according to some embodiments of this specification. Figure 25 and Figure 27 , Figure 27 The arrow a in the figure indicates the acceleration direction of the shell, and the arrow V indicates the velocity direction of the vibration pickup structure. Figure 25 The shell 2510 shown in the figure can be equivalent to mass Ms. The vibration pickup structure 2521 is equivalent to a spring damping mass system Km-Rm-Mm, where Mm represents the sum of the mass of the vibration pickup structure 2521 itself and the additional mass of the liquid attached to the vibration pickup structure 2521. The vibration pickup structure 2521 is connected to the shell 2510, the liquid is equivalent to mass Ml, the spring damping effect between the vibration pickup structure 2521 and Ml is equivalent to Kl-Rl, and the spring damping effect between the shell 2510 and Ml is equivalent to Klb-Rlb. The resonant system corresponding to the pipeline structure 2550 can be equivalent to the spring damping mass system Kl n -Rl n -Ml n , Kl n -Rl n Provided by the gas corresponding to the pipeline structure 2550 and the liquid in the fluid area of the pipeline structure 2550, M1 n The pipeline structure 2550 represents the mass of the liquid in the fluid region corresponding to the pipeline structure 2550. The pipeline structure 2550 is connected to the housing 2510 and is in contact with the liquid. The spring damping effect between the pipeline structure 2550 and M1 is equivalent to Kl'n-Rl'n. The resonant systems corresponding to the multiple pipeline structures 2550 can be equivalent to multiple Kln-Rln-Mln systems in parallel. Here, n can be any positive integer (for example, 1, 2, etc.). In some embodiments, the sensing device can include pipeline structure 1, pipeline structure 2, ... pipeline structure n. Pipeline structure 1 can be equivalent to a spring damping mass system Kl1-Rl1-Ml1, where Kl1-Rl1 is provided by the gas corresponding to pipeline structure 1 (i.e., the gas located at the outlet of pipeline structure 1) and the liquid in the fluid region of pipeline structure 1. Ml1 represents the mass of the liquid in the fluid region corresponding to pipeline structure 1. The spring damping effect between the resonant system corresponding to pipeline structure 1 and M1 is equivalent to Kl'1-Rl'1. The resonant system corresponding to the pipeline structure 2 can be equivalent to the spring-damping mass system Kl2-Rl2-Ml2, where Kl2-Rl2 is provided by the gas corresponding to the pipeline structure 2 and the liquid in the fluid region of the pipeline structure 2. Ml2 represents the liquid mass in the fluid region corresponding to the pipeline structure 2. The spring-damping effect between the pipeline structure 2 and Ml is equivalent to Kl'2-Rl'2.

[0238] Spring-damping mass system Km-Rm-Mm and spring-damping mass system Kl n -Rl n -Ml n Having different elasticity, damping and mass respectively, each spring-damping-mass system can have a different resonance peak, and the sensing device includes multiple spring-damping-mass systems with different resonance peaks, so that the frequency response curve of the sensing device can have multiple resonance peaks. Figure 28 is a frequency response curve of the sensor device shown in some embodiments of this specification. Figure 28 In the figure, the horizontal axis represents frequency in Hertz (Hz), and the vertical axis represents sensitivity in decibels (dBV). Curve 281 is the frequency response curve of the sensor device without liquid and pipe structure, and the resonant frequency f0 corresponding to its resonance peak 2811 is the first resonant frequency. Curve 282 is the frequency response curve of the sensor device with liquid and pipe structure, and the resonant system corresponding to the pipe structure is equivalent to the spring damping mass system (for example, Kl n -Rl n -Ml n ) resonates at the resonant frequency, so that the curve 282 can have multiple resonant peaks (including the resonant peak 2821) and multiple resonant valleys (including the resonant valley 2822). The resonant frequencies corresponding to the multiple resonant peaks are f01, f02, ..., f0 n , the resonant frequencies corresponding to the multiple resonance valleys are f0 -1 、f0 -2 ...f0 -n Here n is related to the spring-damper mass system Kl n -Rl n -Ml n In some embodiments, the relationship between the resonant frequencies corresponding to the multiple resonant peaks can be similar to that of Figure 9 The relationship between the resonant frequencies corresponding to the first (or third) resonant peak 921 and the second (or fourth) resonant peak 922 in the middle curve 920 is not described here. Figure 28, the sensitivity of the sensing device with liquid and pipeline structure is greatly improved compared with the sensing device without liquid and pipeline structure, and the improvement range can be △V4. In some embodiments, △V4 can be 10dBV-60dBV. Preferably, △V4 can be 20dBV-60dBV. Further preferably, △V4 can be 30dBV-50dBV. In some embodiments, the viscosity of the liquid can be reduced so that the amplitude of the resonance peak provided by the pipeline structure is higher, thereby improving the sensitivity of the sensing device in the frequency band near the resonance frequency corresponding to its resonance peak. In some embodiments, the amplitudes of the multiple resonance peaks provided by the multiple pipeline structures can be higher, so that the sensing device can maintain a good response within a wider frequency band.

[0239] The liquid in the fluid region corresponding to the pipeline structure vibrates in the same or opposite direction as the vibration pickup structure, so that a resonant system (for example, a spring-mass system K1) is formed. n -Rl n -Ml n ) of the sensor device has a resonance peak (e.g., Figure 28 The resonance peak 2821) or resonance valley (e.g., Figure 28 The specific principles of the generation of resonance peaks and resonance valleys can be found in Figure 29A and Figure 29B Detailed description. Figure 29A Schematic diagram of the vibration direction of the sensor device at the resonance peak according to some embodiments of this specification. Figure 29A As shown, when the sensor device is at the resonance frequency f0 corresponding to the resonance peak n When the vibration direction of the liquid in the fluid area of the pipe structure 2950A is the same as the vibration direction of the vibration pickup structure 2921A, the liquid vibration displacement is superimposed on the vibration displacement of the vibration pickup structure 2921A, increasing the deformation, so that the sensor device is at f0 n A resonance peak is generated at the Figure 29B According to some embodiments of this specification, the vibration direction of the sensor device in the resonance valley is shown. Figure 29B As shown, when the sensor device is at the resonance frequency f0 corresponding to the resonance peak -n Under the condition that the liquid vibration direction in the fluid region of the pipe structure 2950B is opposite to the vibration direction of the vibration pickup structure 2921B, the liquid vibration displacement and the vibration displacement of the vibration pickup structure 2921B are partially offset, reducing the deformation, so that the sensing device is at f0 -n A resonance valley is generated at the

[0240] In some embodiments, by multi-resonant systems (e.g., Figure 27The spring mass system Kl1-Rl1-Ml1, the spring mass system Kl2-Rl2-Ml2, the spring mass system Kl n -Rl n -Ml n By performing acoustic-to-electrical conversion on the vibration signals near each resonance peak in the image (e.g., the image sensor), the vibration signals can be divided into sub-bands. For example, considering the existence of multiple resonance peaks, a filter is set near the resonance frequency corresponding to each resonance peak. Even if it is a low-order filter, a higher-quality sub-band signal can be extracted. In this way, the sensing device provided in the embodiment of this specification can help realize the sub-band frequency division processing of the full-band signal through its own structure under the premise of low-cost hardware circuits (e.g., filtering circuits) or software algorithms, thereby avoiding the problems of high-cost hardware circuit design complexity and high computing resources occupied by software algorithms, resulting in signal distortion and noise introduction.

[0241] As an example only, the above Figure 28 The method for measuring the frequency response curve of the sensor device shown may include: providing a measurement voltage to the sensor device in a measurement circuit, and plotting the frequency response curve of the sensor device using a level recorder.

[0242] Figure 30 Schematic diagram of the structure of the sensor device according to some embodiments of this specification. Figure 30 As shown, the sensing device 3000 may include a shell 3010, a transducer unit 3020 and a pipeline structure 3050, wherein the shell 3010 has an accommodating cavity inside, the transducer unit 3020 is arranged in the accommodating cavity, the vibration pickup structure divides the accommodating cavity into a front cavity 3030 and a rear cavity 3040 located on opposite sides of the vibration pickup structure, the rear cavity 3040 is filled with liquid, and the liquid is in contact with the vibration pickup structure 3021, the pipeline structure 3050 connects the rear cavity 3040 with the outside of the shell 3010, and the liquid is at least partially located in the pipeline structure 3050. Figure 25 The housing 3010, the transducer unit 3020 and the pipe structure 3050 are shown in FIG. Figure 25 The housing 2510, transducer unit 2520 and pipeline structure 2050 shown are similar and will not be described again here.

[0243] Figure 31A yes Figure 25 Schematic diagram of the structure of part A. Figure 31A As shown, the vibration pickup structure 2521 may include a piezoelectric layer 310A and an electrode layer 320A. The electrode layer 320A may be located on the upper surface and / or lower surface of the piezoelectric layer 310A.

[0244] In some embodiments, the electrode layer 320A includes a first electrode layer 321A and a second electrode layer 322A, and the piezoelectric layer 310 can be located between the first electrode layer 321A and the second electrode layer 322A. In some embodiments, the side of the second electrode layer 320 facing away from the piezoelectric layer 310 is connected to the substrate 2522. When the vibration pickup structure 2521 receives a vibration signal, the vibration pickup structure 2521 deforms or displaces. The piezoelectric layer 310 can generate an electric potential difference under the action of deformation stress based on the piezoelectric effect. The electrode layer 320 (e.g., the first electrode layer 321A and the second electrode layer 322A) can collect this electric potential difference and transmit it to the processor 2523, thereby converting the external vibration signal into an electrical signal.

[0245] In some embodiments, the material of the piezoelectric layer may include piezoelectric crystal material and piezoelectric ceramic material. Piezoelectric crystal material refers to a piezoelectric single crystal.

[0246] In some embodiments, in order to support the electrode layer 320A and the piezoelectric layer 310A or transmit displacement thereto, the vibration pickup structure may further include a substrate layer 330A, which may be located between the second electrode layer 322A and the substrate 2522. In some embodiments, the substrate layer 330A may be a single-layer structure or a multi-layer composite structure made of one or more semiconductor materials. Figure 31A The vibration pickup structure shown is merely exemplary and does not limit the vibration pickup structure to the illustrated embodiment. For example, the vibration pickup structure may include other structural layers or multiple piezoelectric layers. In some embodiments, the vibration pickup structure may further include a first piezoelectric layer and a second piezoelectric layer, with an electrode layer 320 disposed between the first and second piezoelectric layers.

[0247] Figure 31B yes Figure 25 Another structural diagram of part A in FIG. Figure 31B As shown, the vibration pickup structure 2521 may include a first electrode layer 321B, a first piezoelectric layer 311B, a second electrode layer 322B, a second piezoelectric layer 312B and a third electrode layer 323B arranged in sequence from top to bottom, wherein the side of the third electrode layer 323B facing away from the second piezoelectric layer 312B is connected to the substrate 2522.

[0248] When the vibration pickup structure 2521 receives a vibration signal, the piezoelectric layer (for example, the first piezoelectric layer 311B and the second piezoelectric layer 312B) is subjected to deformation stress to generate an electric potential difference (voltage), and the electrode layer (for example, the first electrode layer 321B, the second electrode layer 322B and the third electrode layer 323B) can collect the potential difference and transmit it to the processor 2523, thereby converting the external vibration signal into an electrical signal.

[0249] In some embodiments, the vibration pickup structure can cover the opening of the substrate to prevent the liquid in the front cavity from entering the rear cavity. In some embodiments, one surface of the vibration pickup structure is connected to the side of the substrate away from the bottom wall of the shell and covers the opening of the substrate, and a surface of the vibration pickup structure facing away from the substrate is in contact with the liquid. In some embodiments, the vibration pickup structure can be connected to the side wall of the substrate through its peripheral side, where the vibration pickup structure is adapted to the shape and size of the opening of the substrate. In some embodiments, the shape of the vibration pickup structure can include but is not limited to regular shapes such as circle, rectangle, ellipse, semicircle, polygon, or any irregular shape. The following is combined with Figure 32A and Figure 32B The piezoelectric film and the substrate are exemplified. Figure 32A Schematic diagram of the vibration pickup structure shown in some embodiments of this specification. Figure 32A As shown, in some embodiments, the base 32212A can be a square cylindrical structure with both ends through or one end having an open end, the open shape of the base 32212A can be circular, and the piezoelectric film 32211A can be circular to match the open shape. Figure 32B is a schematic diagram of a vibration pickup structure according to some embodiments of this specification, such as Figure 32B As shown, in some embodiments, the base 32212B can be formed into a square tube structure with both ends through or one end having an open end. The open shape of the base 32212B can be circular, and the piezoelectric film 32211B can be square to match the open shape.

[0250] It should be understood that the piezoelectric film may not be adapted to the shape of the opening. For example, the shape of the piezoelectric film may be square, and the shape of the substrate opening may be triangular.

[0251] In some embodiments, the sensing device may include a plurality of piezoelectric beams. In some embodiments, the plurality of piezoelectric beams may be a plurality of identical piezoelectric beams, for example, the length, thickness, material and other factors of the plurality of piezoelectric beams are the same. When the center of mass of the plurality of piezoelectric beams is located in the same plane, the plurality of piezoelectric beams can provide a better acoustic output effect for the sensing device, which is manifested in that the sensing device can output a larger response when the same excitation signal is input. In some embodiments, the plurality of piezoelectric beams may be a plurality of different piezoelectric beams, for example, the length, thickness, material and other factors of the plurality of piezoelectric beams and their positions are arbitrarily different. A plurality of different piezoelectric beams can provide different resonance peaks for the sensing device, thereby enhancing the response of the sensing device in any specific frequency band (for example, in the frequency range of 20 Hz-1000 Hz). For more information about piezoelectric beams, please refer to the content elsewhere in this specification, for example, Figure 33 、 Figure 35A and Figure 35B and its related descriptions.

[0252] Figure 33Schematic diagram of the vibration pickup structure shown in some embodiments of this specification. Figure 33 As shown, in some embodiments, the vibration pickup structure 3321 may include a base 33212 and four piezoelectric beams 33211, each piezoelectric beam 33211 extending toward the center of the opening of the base 33212, and the four piezoelectric beams 33211 are symmetrically distributed along the geometric center of the opening, and the four piezoelectric beams 33211 together cover the opening of the base 33212. This is for exemplary purposes only. Figure 33 The opening of the middle base is a square, and each piezoelectric beam 33211 can be an isosceles right triangle of the same size. The hypotenuse of each piezoelectric beam 33211 is connected to the side wall of the opening of the base 33212. The right-angled sides of the four piezoelectric beams 33211 are spliced together to form a square with the same shape as the opening.

[0253] In some embodiments, the shape formed by splicing multiple piezoelectric beams includes but is not limited to regular shapes such as circles, rectangles, ellipses, semicircles, polygons, or any irregular shapes. In some embodiments, the shape of each piezoelectric beam may be the same or different, and its shape includes but is not limited to regular shapes such as sectors, triangles, rectangles, semicircles, polygons, or any irregular shapes. In some embodiments, the vibration pickup structure may include a substrate and two piezoelectric beams, and the two piezoelectric beams together cover the substrate opening. In some embodiments, the two piezoelectric beams may be semicircular in shape of the same size, the arc edges of the piezoelectric beams are connected to the side walls of the substrate opening, and the straight edges of the two piezoelectric beams are connected to each other to form a circle that adapts to the opening. In some embodiments, the vibration pickup structure may include a substrate and three piezoelectric beams, and the three piezoelectric beams together cover the substrate opening. In some embodiments, the three piezoelectric beams may be sectors of the same size, the arc edges of the piezoelectric beams are connected to the side walls of the substrate opening, and the straight edges of the three piezoelectric beams are connected in pairs to form a circle that adapts to the opening. In some embodiments, the piezoelectric beam 33211 may include an electrode layer and a piezoelectric layer. For more information on the arrangement of the electrode layer and the piezoelectric layer, please refer to Figure 31A 、 Figure 31B and related content. Figure 33 Base 33212 shown with Figure 25 The illustrated substrate 2522 is similar and will not be described again here.

[0254] To prevent liquid in the front and / or rear cavities from flowing through the gaps between the piezoelectric beams 33211, in some embodiments, the vibration pickup structure may further include a blocking structure 33213, which fills or covers the gaps between the multiple piezoelectric beams 33211. For example, the blocking structure 33213 may be located on the upper or lower surface of the multiple piezoelectric beams 33211 to cover the gaps between the multiple piezoelectric beams 33211. For another example, the blocking structure 33213 may be located in the gap between two adjacent piezoelectric beams 33211. For another example, a portion of the blocking structure 33213 may fill the gap between two adjacent piezoelectric beams 33211, and another portion may be located on the upper or lower surface of the multiple piezoelectric beams 33211 to cover the gaps between the multiple piezoelectric beams 33211. Considering that the blocking structure 33213 will hinder the vibration of the piezoelectric beam connected to it, in some embodiments, in order to minimize this effect, the material of the blocking structure 33213 can be selected to have a smaller Young's modulus. For example, the Young's modulus of the blocking structure 33213 should be smaller than the Young's modulus of the electrode layer or the piezoelectric layer. In some embodiments, the material of the blocking structure 33213 can be a semiconductor material, a non-metallic material or a flexible material. Exemplary non-metallic materials may include plastics (for example, polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS) and acrylonitrile-butadiene-styrene copolymer (ABS)), composite materials (for example, non-metallic matrix composite materials), etc. or any combination thereof. Exemplary flexible materials may include rubber, latex, silicone, sponge, etc. or any combination thereof. For the manner in which the blocking structure fills or covers the gaps between multiple piezoelectric beams, please refer to Figures 34A-34D Related content.

[0255] Figure 34A According to some embodiments of this specification Figure 33 The cross-section of BB. Figure 34A As shown, the blocking structure 34213A fills the gap between two adjacent piezoelectric beams 34211A. In some embodiments, the periphery of the blocking structure 34213A can be connected to the corresponding piezoelectric beam 34211A at the gap. In some embodiments, along the vibration direction of the piezoelectric beam 34211A, the end surface of the blocking structure 34213A can be flush with the surface of the piezoelectric beam 34211A. In some embodiments, along the vibration direction of the piezoelectric beam 34211A, the end surface of the blocking structure 34213A can be protruding or recessed relative to the surface of the piezoelectric beam 34211A.

[0256] Figure 34B According to some embodiments of this specification Figure 33 The cross-section of BB. Figure 34BAs shown, the blocking structure 34213B covers the gap between two adjacent piezoelectric beams 34211B, and the blocking structure 34213B is located on the side of the piezoelectric beam 34211B away from the substrate 34212B.

[0257] Figure 34C According to some embodiments of this specification Figure 33 The cross-section of BB. Figure 34C As shown, the blocking structure 34213C covers the gap between two adjacent piezoelectric beams 34211C, and the blocking structure 34213C is located on a side of the piezoelectric beam 34211C close to the substrate 34212C.

[0258] In order to further improve the filling and sealing of the gap between the piezoelectric beams by the blocking structure, the blocking structure may cover and fill the gap between two adjacent piezoelectric beams. Figure 34D According to some embodiments of this specification Figure 33 The cross-section of BB. Figure 34D As shown, blocking structure 34213D surrounds the gaps between piezoelectric beams 34211D.

[0259] In some embodiments, the blocking structure 34213D includes a first structural portion 1, a second structural portion 2, and a third structural portion 3. The first structural portion 1 fills the gap between two adjacent piezoelectric beams 34211D. The second structural portion 2 and the third structural portion 3 respectively cover the gap between two adjacent piezoelectric beams 34211D. The second structural portion 2 is located on the side of the piezoelectric beam 34211D away from the base 34212D, and the third structural portion 3 is located on the side of the piezoelectric beam 34211D closer to the base 34212D. In some embodiments, the circumference of the first structural portion 1 can be connected to the corresponding piezoelectric beam 34211D in the gap. In some embodiments, along the vibration direction of the piezoelectric beam 34211D, the end surface of the first structural portion 1 can be flush with the surface of the piezoelectric beam 34211D. In some embodiments, along the vibration direction of the piezoelectric beam 34211D, the end surface of the first structural portion 1 can be recessed relative to the surface of the piezoelectric beam 34211D. In some embodiments, the first structure portion 1 , the second structure portion 2 and the third structure portion 3 of the blocking structure 34213D may be independent structures or may be an integral whole (eg, integrally formed).

[0260] Optionally, when the gap between the piezoelectric beams is small enough, the surface of the piezoelectric beams will produce a sufficient blocking effect on the liquid, so that the liquid will not pass through the gap. In some embodiments, in order for the surface of the piezoelectric beams to produce a sufficient blocking effect on the liquid, the gap between the piezoelectric beams may be no greater than 20um. Taking into account the relatively low density of the liquid that may be used, in order to prevent the liquid with lower density from passing through the gap between the piezoelectric beams, preferably, the gap between the piezoelectric beams may be no greater than 15um. During the use of the sensing device, the liquid in the accommodating cavity may be impacted by external forces and pass through the gap. In order to avoid this situation as much as possible, it is further preferred that the gap between the piezoelectric beams may be no greater than 10um.

[0261] Figure 35A is a schematic structural diagram of a sensing device according to some embodiments of this specification, Figure 35B It is a structural schematic diagram of the vibration pickup structure shown in some embodiments of this specification. Figure 35A The sensing device 3500 shown is Figure 25 The overall structure of the sensor device 2500 shown is roughly the same, and the main difference is that the vibration pickup structure is different. Figure 35A and Figure 35B As shown, the vibration pickup structure 3521 may include a piezoelectric beam 35211 and a second membrane structure 35213. The base 3522 is a structure with an open opening, the piezoelectric beam 35211 is disposed at the opening, and the second membrane structure 35213 covers the opening of the base 3522. Figure 35A The housing 3510 and the duct structure 3550 shown are Figure 25 The shell 2510 and the pipe structure 2550 shown in FIG are similar in structure, and the base 3522 is similar to the base 3522. Figure 25 The illustrated substrate 2522 is similar and will not be described again here.

[0262] In some embodiments, the piezoelectric beam 35211 may be a cantilever beam structure having an elongated shape, with a fixed end and a free end at the two ends of the piezoelectric beam 35211. The fixed end may be connected to the side of the substrate, and the free end may be suspended at an open portion of the substrate. In some embodiments, the piezoelectric beam 35211 may include an electrode layer and a piezoelectric layer, both of which are arranged along their long axis ( Figure 35A e direction shown) and along its thickness direction ( Figure 35A For more information on the arrangement of the electrode layer and the piezoelectric layer, please refer to Figure 31A 、 Figure 31BAnd related content. In some embodiments, the polarization direction of the piezoelectric beam 35211 is perpendicular to the stress direction. Here, when the piezoelectric beam 35211 is subjected to a vibration signal transmitted by the substrate, the direction of the stress to which the piezoelectric beam 35211 is subjected during the vibration process is the direction of its long axis. The piezoelectric beam 35211 is deformed as a whole, and the polarization direction is perpendicular to its long axis. After the piezoelectric layer is subjected to deformation stress, an electric potential difference (voltage) is generated between its upper and lower surfaces. The electrode layers (for example, the first electrode layer and the second electrode layer) located on both sides of the piezoelectric layer can collect the potential difference to convert the external vibration signal into an electrical signal. A single piezoelectric beam can be regarded as a signal acquisition unit, which can have a unique resonance peak. In some embodiments, the resonant frequency corresponding to the resonance peak of the piezoelectric beam 35211 can be adjusted by adjusting the structural parameters of the piezoelectric beam 35211 (for example, the volume, mass, width of the piezoelectric beam and the thickness of the piezoelectric layer and electrode layer, etc.).

[0263] In order to improve the sensitivity of the sensing device within a wider frequency band, multiple piezoelectric beams 35211 can be provided, and the multiple piezoelectric beams 35211 can vibrate to generate resonance peaks of different frequencies. Each piezoelectric beam 35211 can serve as a separate signal acquisition unit to output a sub-electrical signal. In some embodiments, each sub-electrical signal can be directly output to the processor in the form of electrical series, parallel, or series-parallel combination (for example, Figure 25The processor 2523 is shown). In some embodiments, each sub-electrical signal can be transmitted separately to the processor, which performs signal processing on each sub-electrical signal separately (including but not limited to adjusting the amplitude, phase, etc.), and then performs corresponding signal fusion. More descriptions about the processing methods of the sub-electrical signals of each piezoelectric beam can be found in, for example, the PCT application entitled "MICROPHONE AND ELECTRONIC DEVICE HAVING THE SAME" with application number PCT / CN2020 / 103201, the contents of which are incorporated herein by reference. In some embodiments, the opening of the substrate can be rectangular, the fixed end of the piezoelectric beam 35211 can be connected to any side wall of the opening, the free end of the piezoelectric beam 35211 can be suspended in the opening, and the fixed end of the piezoelectric beam 35211 is spaced apart on the side wall of the opening. In some embodiments, the fixed ends of multiple piezoelectric beams 35211 can be set on the same side wall of the opening. In some embodiments, the multiple piezoelectric beams 35211 on the same side wall of the opening are spaced apart in sequence. In some embodiments, the plurality of piezoelectric beams 35211 spaced apart on the same sidewall of the opening are in the same plane and approximately parallel. In some embodiments, the plurality of piezoelectric beams 35211 may be disposed on opposing sidewalls of the opening. In some embodiments, the free ends of the plurality of piezoelectric beams 35211 disposed on opposing sidewalls of the opening are spaced apart within the opening. In some embodiments, the plurality of piezoelectric beams 35211 disposed on opposing sidewalls of the opening are in the same plane and approximately parallel. In some embodiments, the plurality of piezoelectric beams may be disposed on all four sidewalls of the opening, for example, the free ends of the piezoelectric beams 35211 disposed on all four sidewalls of the opening extend toward their opposing sidewalls of the opening.

[0264] In some embodiments, the opening may be annular, and the fixed ends of the plurality of piezoelectric beams may be spaced apart on the annular inner wall of the opening. The fixed ends of the piezoelectric beams may be approximately perpendicular to the annular inner wall. The fixed ends of the piezoelectric beams 35211 extend toward the center of the opening and are suspended in the opening, so that the plurality of piezoelectric beams are distributed in an annular pattern in the same plane. In some embodiments, the opening may also be a polygonal structure (e.g., a triangle, a pentagon, a hexagon, etc.), in which case the fixed ends of the plurality of piezoelectric beams may be spaced apart along at least one side wall of the opening in the same plane. In some embodiments, a plurality of different piezoelectric beams with different resonant frequencies (e.g., piezoelectric beams with different structural parameters) may be provided so that the vibration pickup structure generates a frequency response with multiple resonant peaks to the vibration signal of the shell. Since the piezoelectric beam is sensitive to vibrations near its resonant frequency, it can be considered that the piezoelectric beam has a frequency-selective characteristic for the vibration signal. That is, the piezoelectric beam will primarily convert the sub-band vibration signal of the vibration signal near its resonant frequency into an electrical signal.

[0265] In some embodiments, by setting different structural parameters, different piezoelectric beams can have different resonant frequencies, thereby forming sub-bands near each resonant frequency. In some embodiments, by adjusting the structural parameters of multiple piezoelectric beams to be different, at least 5 sub-bands can be formed within the human voice frequency range (e.g., 20 Hz-16000 Hz). In some embodiments, by adjusting the structural parameters of multiple piezoelectric beams to be different, 5 to 11 sub-bands can be formed within the human voice frequency range (e.g., 20 Hz-16000 Hz). In some embodiments, by adjusting the structural parameters of multiple piezoelectric beams to be different, 6 to 24 sub-bands can be formed within the human voice frequency range (e.g., 20 Hz-16000 Hz). It should be noted that the frequency ranges of the piezoelectric beams, the number of sub-bands, and the resonant frequencies corresponding to each sub-band are not limited to the above description. They can be adaptively adjusted according to specific circumstances such as the application scenario of the microphone and the size of the sensing device, and are not further limited here.

[0266] In some embodiments, the output at the resonant peak of each piezoelectric beam is significantly greater than the output within other frequency ranges. By extracting the signals generated by each piezoelectric beam separately, it is possible to perform sub-band frequency division of the full-frequency sound signal. In some embodiments, each sub-band can be processed separately (e.g., for denoising, amplitude modulation, etc.), and then the processed sub-band signals are fused to produce a sensor device with a high signal-to-noise ratio and a flatter frequency response curve. In some embodiments, the electrical signals of each piezoelectric beam can be output to a processor in the form of an electrical series connection, parallel connection, or a combination of series and parallel connections. Alternatively, the electrical signals of each piezoelectric beam can be output separately to a processor, which then processes the electrical signals of each piezoelectric beam 35211 separately, thereby achieving frequency band fusion. By setting up multiple piezoelectric beams in the sensing device and utilizing the characteristics of the piezoelectric beams (for example, piezoelectric beam 35211) with different resonant frequencies, the vibration signal can be filtered and the frequency band decomposition can be achieved, thereby avoiding the complexity of the filtering circuit used in the sensing device and the high computing resources occupied by the software algorithm, which brings about signal distortion and noise introduction, thereby reducing the complexity and production cost of the sensing device.

[0267] In some embodiments, different piezoelectric beams can be provided to increase resonance peaks in different frequency ranges, thereby improving the sensitivity of the sensing device near multiple resonance peaks and thereby improving the sensitivity of the sensing device within a wider frequency band.

[0268] In some embodiments, a surface of the second membrane structure 35213 can be connected to the side of the base 3522 away from the bottom wall of the shell and cover the opening of the base 3522, and a surface of the second membrane structure 352113 facing away from the base is in contact with the liquid. In some embodiments, the second membrane structure 35213 can be connected to the side wall corresponding to the opening of the base 3522 through its circumferential side, where the second membrane structure 35213 is adapted to the shape and size of the opening of the base 3522. In some embodiments, the shape of the second membrane structure 35213 can include, but is not limited to, regular shapes such as circular, rectangular, elliptical, semicircular, polygonal, or any irregular shape. By providing the second membrane structure 35213, liquid can be effectively prevented from flowing into another cavity through the gap between the piezoelectric beams or between the piezoelectric beam and the base, thereby effectively improving the reliability of the sensing device.

[0269] In some embodiments, the second membrane structure 35213 can be connected to the plurality of piezoelectric beams 35211. In some embodiments, the second membrane structure 35213 can be connected to the circumference of the piezoelectric beams 35211. In some embodiments, the second membrane structure 35213 can be connected to the side of the piezoelectric beams 35211 closest to the substrate 3522. In some embodiments, the second membrane structure 35213 can be connected to the side of the piezoelectric beams 35211 away from the substrate 3522. Considering that the second membrane structure 35213 may hinder the vibration of the piezoelectric beams to which it is connected, in some embodiments, to minimize this effect, the material of the second membrane structure 35213 can be selected to have a low Young's modulus. For example, the Young's modulus of the blocking structure 35213 should be smaller than the Young's modulus of the electrode layer or the piezoelectric layer. In some embodiments, the material of the second membrane structure 35213 can include, but is not limited to, one or more of a semiconductor material, a metal material, a metal alloy, an organic material, and the like. In some embodiments, semiconductor materials can include, but are not limited to, silicon, silicon dioxide, silicon nitride, silicon carbide, and the like. In some embodiments, the metal material may include, but is not limited to, copper, aluminum, chromium, titanium, gold, etc. In some embodiments, the metal alloy may include, but is not limited to, copper-aluminum alloy, copper-gold alloy, titanium alloy, aluminum alloy, etc. In some embodiments, the organic material may include, but is not limited to, polyimide, parylene, PDMS, silicone gel, silicone gel, etc.

[0270] Figure 36A It is a schematic structural diagram of a sensing device according to some embodiments of this specification. Figure 36A The sensing device 3600A shown is Figure 25 The overall structure of the sensor device 2500 shown is roughly the same, and the main difference is that the transducer unit is different. Figure 36A The housing 3610A and the duct structure 3650A shown are Figure 25 The structures of the housing 2510 and the pipe structure 2550 shown in FIG are similar and will not be described in detail here. Figure 36A As shown, the sensor device 3600A may include a housing 3610A and a transducer unit. The housing 3610A has a housing cavity within which the transducer unit is disposed. The vibration pickup structure divides the housing cavity into a front cavity 3630A and a rear cavity 3640A located on opposite sides of the vibration pickup structure. The transducer unit includes a capacitive transducer 3623A, which includes a perforated back plate 36231A and a diaphragm 36232A.

[0271] In some embodiments, the transducer unit may further include a substrate 36212A, wherein the substrate 36212A is Figure 25 The illustrated substrate 2522 is similar and will not be described in detail here. The capacitive transducer 3623A can cover the open arrangement of the substrate 36212A. The perforated back plate 36231A is arranged approximately parallel to the diaphragm 36232A. In some embodiments, a gasket 36233A is provided between the perforated back plate 36231A and the diaphragm 36232A to separate the two. The diaphragm 36232A can cover the open arrangement of the substrate 36212A. In some embodiments, the side of the diaphragm 36232A close to the substrate 36212A can be connected to the side of the substrate 36212A away from the bottom wall of the housing 3610A. The perforated back plate 36231A is arranged in the open arrangement of the substrate 36212A, and the peripheral side of the perforated back plate 36231A can be connected to the inner wall of the open arrangement. In some embodiments, when the cavity near the diaphragm 36232A is filled with liquid, the liquid contacts the diaphragm 36232A. The liquid cannot flow between the diaphragm 36232A and the back plate 36231A with holes. When the capacitive transducer 3623A receives a vibration signal, the diaphragm 36232A vibrates so that the distance between it and the back plate 36231A with holes changes, thereby generating an electrical signal. In some embodiments, the material of the diaphragm 36232A and the material of the back plate 36231A with holes can be conductive materials (for example, copper, aluminum, graphite, etc.). In some embodiments, the diaphragm 36232A can be a non-conductive polymer elastic film, and a conductive layer (for example, an aluminum film layer) is plated on at least one side of the polymer elastic film, and the material of the back plate 36231A with holes can be a conductive material. For example, the material of the polymer elastic film may include, but is not limited to, one or more of polyethylene terephthalate (PET), polycarbonate (PC), polyvinyl chloride (PVC), acrylonitrile-butadiene-styrene copolymer (ABS), and polyethylene (PE).

[0272] In order to reduce the Q value of multiple resonance peaks and resonance valleys on the frequency response curve of the sensor device, Figure 36A On the basis of Figure 36B The structure of the sensing device is shown. Figure 36B It is a schematic structural diagram of a sensing device according to some embodiments of this specification. Figure 36B The sensing device 3600B shown is Figure 36A The overall structure of the sensor device 2500 shown is substantially the same, and the main difference is that the capacitive transducer is installed in a different manner. Figure 36B The shell 3610B, the front cavity 3630B, the rear cavity 3640B, the pipe structure 3650B, the base 36212B, the back plate with holes 36231B, the diaphragm 36232B and the gasket 36233B are shown. Figure 36A The structures of the housing 3610A, front cavity 3630A, rear cavity 3640A, pipe structure 3650A, base 36212A, back plate with holes 36231A, diaphragm 36232A and gasket 36233A shown in FIG are similar and are not described in detail here. Figure 36B As shown, the cavity near the perforated back plate 36231B is filled with liquid. The liquid contacts the perforated back plate 36231B and can penetrate between the perforated back plate 36231B and the diaphragm 36232B through the holes on the perforated back plate 36231B. This can increase the overall damping of the capacitive transducer 3623B, thereby achieving damping adjustment of the sensing device, thereby achieving the purpose of smoothing the frequency response curve. In addition, after the liquid flows in, a dielectric layer is formed between the diaphragm 36232B and the back plate 36231B. By selecting the type of liquid, it is possible to adjust the parameters such as the dielectric constant of the electrostatic structure and improve the efficiency of the capacitive transducer in generating electrical signals. In some embodiments, the pores on the perforated back plate 36231B can be reduced so that the pores have a confining effect on the liquid. In this way, the space between the perforated back plate 36231B and the diaphragm 36232B may not be completely filled with liquid, and some air domains may still exist, thereby achieving the adjustment of the resonant frequency (for example, the first resonant frequency f0) of the capacitive transducer.

[0273] Figure 37 It is a schematic structural diagram of a sensing device according to some embodiments of this specification. Figure 37 The sensing device 3700 shown is Figure 25 The overall structure of the sensor device 2500 shown is substantially the same. Figure 37 The transducer unit and piping structure 3750 shown is similar to Figure 25 The structures of the transducer unit and the pipeline structure 2550 shown in FIG are similar and will not be described in detail here. Figure 37 As shown, the sensing device 3700 may include a shell 3710, a transducer unit and a pipe structure 3750. The pipe structure 3750 is located at the top of the shell 3710 along the gravity direction. The transducer unit is arranged in the accommodating cavity. The vibration pickup structure 3721 divides the accommodating cavity into a front cavity 3730 and a rear cavity 3740 located on opposite sides of the vibration pickup structure 3721. The front cavity 3730 is filled with liquid.

[0274] In some embodiments, no restraining structure exists at the interface between the liquid and gas within the pipe structure 3750. Due to the inherent viscosity of the liquid, a very low-rigidity gas-liquid interface forms between the liquid and the gas outside the pipe structure. The liquid's overall added stiffness to the transducer unit is minimal, thus achieving a higher output. Furthermore, this gas-liquid interface reduces the stiffness of the resonant system corresponding to the pipe structure, thereby providing the transducer unit with a lower resonant peak and improving the low-frequency response of the sensing device.

[0275] Figure 38 It is a schematic structural diagram of a sensing device according to some embodiments of this specification. Figure 38 The sensing device 3800 shown is Figure 25 The overall structure of the sensor device 2500 shown is roughly the same, the difference between the two is that, Figure 38 The sensor device 3800 shown also includes a first membrane structure 3860. Figure 38 The transducer unit and piping structure 3850 shown are Figure 25 The structures of the transducer unit and the pipeline structure 2550 shown in FIG are similar and will not be described in detail here. Figure 38 As shown, the sensing device 3800 may include a shell 3810, a transducer unit and a pipeline structure 3850. The transducer unit is arranged in the accommodating cavity. The vibration pickup structure 3821 divides the accommodating cavity into a front cavity 3830 and a rear cavity 3840 located on opposite sides of the vibration pickup structure 3821. The front cavity is filled with liquid.

[0276] The first membrane structure 3860 is positioned between the liquid in the pipe structure 3850 and the gas outside the housing. In some embodiments, the first membrane structure 3860 is disposed within the pipe structure 3850 and connected to the inner wall of the pipe structure 3850 via its circumferential side. Specifically, the first membrane structure 3860 serves to isolate the liquid and gas and constrain the liquid within the pipe structure 3850 to better prevent the liquid from overflowing the pipe structure. Furthermore, the stiffness provided by the first membrane structure 3860 can adjust the resonant frequency of the resonant system formed by the liquid and gas, thereby improving the frequency response of the sensing device 3800. In some embodiments, the structure and material of the first membrane structure 3860 can be designed to adjust the resonant position of the additional resonant system formed by the liquid and gas cavity introduced into the sensing device 2500, as well as the resonant position of the transducer unit, thereby achieving a highly sensitive sensing device within the confined liquid boundary. In some embodiments, the first membrane structure 3860 can be a membrane structure that exhibits flexibility (e.g., high yield strength and resistance to high-temperature deterioration) and softness (e.g., low hardness and easy deformation). For example, first membrane structure 3860 can be made of one or more of polyimide film (PI film), polydimethylsiloxane film (PDMS film), polyurethane (PU), polyetheretherketone (PEEK), a semiconductor flexible film, silicone adhesive, silicone film, silicone gel, damping adhesive (e.g., acrylic damping adhesive), etc. In some embodiments, the thickness of first membrane structure 3860 can range from 0.05 mm to 0.15 mm.

[0277] By forming different degrees of constraints on the liquid in the pipeline structure, the frequency response curve of the sensing device can be adjusted. Figure 39 is a frequency response curve of the sensor device according to some embodiments of this specification. Figure 39As shown, the abscissa represents frequency in Hertz (Hz), and the ordinate represents sensitivity in decibels (dBV). Curve 391 is the frequency response curve of a sensor device without a liquid and pipe structure. Curve 392 is the frequency response curve of a sensor device with a liquid and pipe structure where the pipe structure does not constrain the liquid (i.e., a gas-liquid interface is formed between the liquid and gas in the pipe structure). Curve 393 is the frequency response curve of a sensor device with a liquid and pipe structure where the pipe structure does not constrain the liquid (i.e., the pipe structure includes a first membrane structure 3860 positioned between the liquid and gas). Both curves 392 and 393 show a significant output increase compared to curve 391, indicating that the sensitivity of a sensor device with a liquid and pipe structure can be significantly improved compared to a sensor device without a liquid and pipe structure. The locations of the resonance peak and resonance valley of curve 392 differ from those of curve 393, indicating that by changing the degree of constraint at the interface between the liquid and gas in the pipe structure, the locations of the resonance peak and resonance valley corresponding to the resonant system of the pipe structure can be effectively changed. In some embodiments, the sensor device includes multiple pipe structures. In order to better adjust the position of the resonance peak that each pipeline structure can provide, a first membrane structure 3860 that separates the liquid and the gas can be set on part of the pipeline structure, so that the liquid and the gas form a gas-liquid interface in the part of the pipeline structure.

[0278] Figure 40 It is a schematic structural diagram of a sensing device according to some embodiments of this specification. Figure 40 The sensor device shown is Figure 25 The overall structure of the sensor device shown is roughly the same, with the main difference being that it also includes a first gas cavity 4060. Figure 40 The transducer unit and pipeline structure shown are similar to Figure 25 The structures of the transducer unit and pipeline shown in FIG are similar and will not be described in detail here. Figure 40 As shown, outside the duct structure, another housing 4050 encloses a first gas chamber 4060. The front chamber 4030 is filled with liquid. The first gas chamber 4060 is located near the front chamber 4030 and away from the rear chamber 4040, and the first gas chamber 4060 is in communication with the front chamber 4030. In some alternative embodiments, the first gas chamber 4060 may be formed by the housing 4010 as well, that is, the housing 4010 and the housing 4050 may be an integrally formed housing structure. In this case, the "exterior of the housing" described elsewhere in this specification may be understood as referring to the exterior of the housing structure that constitutes the front or rear chamber described herein. For example, when the housing 4010 and the housing 4050 are integrally formed, the first gas chamber 4060 may be considered the exterior of the housing 4010. In this case, the duct structure connects the accommodating cavity formed by the housing 4010 with the exterior of the housing 4010, i.e., the first gas chamber 4060.

[0279] In some embodiments, a gas-liquid interface can be formed between the gas within the first gas cavity 4060 and the liquid within the front cavity 4030. In some embodiments, a membrane structure can be provided between the gas within the first gas cavity 4060 and the liquid within the front cavity 4030 to isolate the gas from the liquid. In some embodiments, by adding a gas cavity connected to the liquid, the compressibility of the gas can be reduced, thereby increasing the equivalent stiffness of the resonant system corresponding to each pipe structure. In this case, each pipe structure can provide a higher-frequency resonant peak compared to when the first gas cavity 4060 is not provided.

[0280] In some embodiments, when the rear cavity is filled with liquid, the first gas cavity may also be in communication with the rear cavity. In this case, a membrane structure for isolating the gas and the liquid may or may not be provided between the gas in the first gas cavity and the liquid in the rear cavity.

[0281] Figure 41 It is a schematic structural diagram of a sensing device according to some embodiments of this specification. Figure 41 The sensor device shown is Figure 25 The overall structure of the sensor device shown is roughly the same, with the main difference being that it also includes a second gas chamber 4160. Figure 41 The transducer unit and pipeline structure shown are similar to Figure 25 The structures of the transducer unit and pipeline shown in FIG are similar and will not be described in detail here. Figure 41 As shown, on the side of the housing 4110 facing away from the pipe structure, a second gas chamber 4160 is enclosed by another housing 4120. The front chamber 4130 is filled with liquid. The second gas chamber 4160 is located near the rear chamber 4140 and away from the front chamber 4130, and the second gas chamber 4160 is connected to the rear chamber 4140. The connection between the second gas chamber 4160 and the rear chamber 4140 can increase the volume of the rear chamber of the sensor device, thereby reducing the equivalent stiffness of the vibration pickup structure and shifting the first resonant frequency toward lower frequencies, thereby improving the frequency response of the sensor device in the lower frequency band. In some embodiments, the second gas chamber 4160 can be of any shape, such as a cube. In some alternative embodiments, the second gas chamber 4160 can be formed by the housing 4110, that is, the housing 4110 and the housing 4120 can be an integrally formed housing structure.

[0282] Figure 42 It is a schematic structural diagram of a sensing device according to some embodiments of this specification. Figure 42 The sensor device shown is Figure 25 The overall structure of the sensor device shown is roughly the same, the main difference is that the shell is also provided with air holes. Figure 42 The transducer unit and pipeline structure shown are similar to Figure 25 The structures of the transducer unit and pipeline shown in FIG are similar and will not be described in detail here. Figure 42 As shown, the front cavity 4230 is filled with liquid, and the air hole 4241 is set at the position of the shell 4210 corresponding to the rear cavity 4240, and the air hole 4241 connects the rear cavity 4240 with the outside.

[0283] In some embodiments, the front cavity 4230 is filled with liquid, and one or more air holes 4241 are provided at locations on the housing 4210 corresponding to the rear cavity 4240. These air holes 4241 connect the rear cavity 4240 to the outside world, which can be considered as increasing the volume of the sensor device's rear cavity, thereby reducing the equivalent stiffness of the vibration pickup structure and shifting the first resonant frequency toward lower frequencies, thereby improving the sensor device's frequency response in lower frequency bands. In some embodiments, the air holes 4241 can be of any shape, such as circular, square, or triangular.

[0284] Figure 43 It is a schematic structural diagram of a sensing device according to some embodiments of this specification. Figure 43 The sensor device shown is Figure 42 The overall structure of the sensor device shown is roughly the same, the main difference is that the pores are covered with a third membrane structure. Figure 43 The transducer unit and pipeline structure shown are similar to Figure 25 The structures of the transducer unit and pipeline shown in FIG are similar and will not be described in detail here. Figure 43 The front cavity 4330 is filled with liquid, and the air hole is set at the position of the shell 4310 corresponding to the rear cavity 4340, and the air hole is covered with a third membrane structure 4342.

[0285] In some embodiments, the third membrane structure 4342 can isolate the gas in the rear cavity 4340 from the external gas. In some embodiments, the third membrane structure 4342 is connected to the shell 4310 near the side of the shell 4310. In some embodiments, the peripheral side of the third membrane structure 4342 is connected to the pore wall. In some embodiments, the peripheral side of the third membrane structure 4342 is connected to the inner wall of the rear cavity 4340. In some embodiments, the shape of the third membrane structure 4342 may include but is not limited to regular shapes such as circular, rectangular, elliptical, semicircular, polygonal, or any irregular shape. In some embodiments, the material of the third membrane structure 4342 may include but is not limited to one or more of semiconductor materials, metal materials, metal alloys, organic materials, etc. Compared to Figure 42 In this structure, the third membrane structure 4342 forms a relatively rigid constraint on the gas in the rear cavity 4340, thereby increasing the equivalent stiffness of the vibration pickup structure and shifting the first resonant frequency toward higher frequencies, thereby improving the frequency response of the sensing device at higher frequencies. In some embodiments, when the peripheral side of the third membrane structure 4342 is connected to the pore wall, the shape of the third membrane structure 4342 can be adapted to the shape of the pore.

[0286] It should be noted that the above description of the sensor device is merely illustrative and does not limit this specification to the embodiments described. For example, the first gas chamber and the liquid-filled chamber may be connected via a connecting channel. For another example, the third membrane structure may be a planar membrane structure or a three-dimensional membrane structure (e.g., an airbag).

[0287] It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects that may be produced may be any one or a combination of the above, or any other possible beneficial effects.

[0288] The basic concepts have been described above. It will be apparent to those skilled in the art that the detailed disclosure above is merely illustrative and does not limit the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and amendments to the present application. Such modifications, improvements, and amendments are suggested in the present application and remain within the spirit and scope of the exemplary embodiments of the present application.

Claims

1. A sensing device comprising: A housing, wherein the housing has an accommodating cavity therein; a transducer unit comprising a vibration pickup structure for picking up vibration of the housing and generating an electrical signal, wherein the transducer unit is divided within the accommodating cavity into a front cavity and a rear cavity located on opposite sides of the vibration pickup structure, wherein at least one of the front cavity or the rear cavity is filled with a liquid, and the liquid is in contact with the vibration pickup structure; and One or more pipeline structures, each pipeline structure is configured to connect the accommodating cavity with the outside of the shell, and the liquid is at least partially located in the one or more pipeline structures; the transducer unit is connected to a processor, and the processor is configured to process the electrical signal.

2. The sensing device according to claim 1, wherein: The resonance system corresponding to the one or more pipeline structures causes the sensing device to generate at least one resonance peak and resonance valley, the vibration pickup structure has a first resonance frequency, and the resonance frequency of at least one resonance system corresponding to the one or more pipeline structures is less than the first resonance frequency.

3. The sensing device according to claim 1, wherein: The one or more pipeline structures include a plurality of pipeline structures, and the cavity volumes of the plurality of pipeline structures are different.

4. The sensing device according to claim 1, wherein: A gas-liquid interface is formed between the liquid in the one or more pipe structures and the gas outside the housing.

5. The sensing device according to claim 1, wherein: A first membrane structure is included, the first membrane structure being located between liquid in the one or more conduit structures and gas outside the housing.

6. The sensing device according to any one of claims 1 to 5, characterized in that: The vibration pickup structure includes a piezoelectric film, and the transducer unit also includes a substrate. The substrate is a structure with an open opening. The piezoelectric film covers the opening of the substrate. One end of the substrate away from the piezoelectric film is connected to the shell.

7. The sensing device according to any one of claims 1 to 5, characterized in that: The vibration pickup structure includes a plurality of piezoelectric beams, and the energy conversion unit further includes a substrate. The substrate is a structure with an open opening. Each piezoelectric beam is respectively connected to the substrate and extends toward the center of the opening.

8. The sensing device according to claim 7, characterized in that A blocking structure is included that fills or covers gaps between the plurality of piezoelectric beams.

9. The sensing device according to any one of claims 1 to 5, characterized in that: The transducer unit also includes a substrate, which is a structure with an open opening; the vibration pickup structure includes: a plurality of piezoelectric beams, which are spaced apart and distributed at the opening, and the vibrations of the plurality of piezoelectric beams produce resonance peaks of different frequencies; and a second membrane structure, which covers the opening of the substrate, and an end of the substrate facing away from the second membrane structure is connected to the shell.

10. The sensing device according to any one of claims 1 to 5, characterized in that: The transducer unit includes a capacitive transducer, and the capacitive transducer includes at least a back plate with a hole and a diaphragm.

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