Bone conduction microphone

Abstract

The application discloses a bone conduction microphone, comprising: a laminated structure formed by a vibration unit and an acoustic transducing unit; a base structure configured to carry the laminated structure, at least one side of the laminated structure being connected to the base structure in a physical manner; the base structure generates vibration based on an external vibration signal, the vibration unit deforms in response to the vibration of the base structure; the acoustic transducing unit generates an electrical signal based on the deformation of the vibration unit; wherein the resonance frequency of the bone conduction microphone is 2.5 kHz-4.5 kHz.

Description

[0001] Cross-references

[0002] This application claims priority to international application PCT / CN2020 / 142533, filed on December 31, 2020, the contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of hearing equipment technology, and in particular to a bone conduction microphone. Background Technology

[0004] Microphones receive external vibration signals, convert them into electrical signals using an acoustic transducer, and then output the electrical signal after processing by back-end circuitry. Air conduction microphones receive air-conducted sound signals, which propagate through the air; that is, they receive air vibration signals. Bone conduction microphones receive bone-conducted sound signals, which propagate through the human skeleton; that is, they receive bone vibration signals. Compared to air conduction microphones, bone conduction microphones have advantages in noise immunity. In noisy environments, bone conduction microphones are less affected by ambient noise and can effectively capture human voices.

[0005] Existing bone conduction microphones are overly complex in structure and require sophisticated manufacturing processes; insufficient connection strength of some components leads to reliability issues, affecting the output signal. Therefore, it is necessary to provide a bone conduction microphone with a simple structure and high stability. Summary of the Invention

[0006] One aspect of this application provides a bone conduction sound transmission device, comprising: a stacked structure formed by a vibrating unit and an acoustic transducer; a substrate structure configured to support the stacked structure, at least one side of the stacked structure being physically connected to the substrate structure; the substrate structure generating vibration based on an external vibration signal, the vibrating unit deforming in response to the vibration of the substrate structure; and the acoustic transducer generating an electrical signal based on the deformation of the vibrating unit.

[0007] In some embodiments, the resonant frequency of the bone conduction microphone is 2.5 kHz to 4.5 kHz.

[0008] In some embodiments, the resonant frequency of the bone conduction microphone is 2.5 kHz to 3.5 kHz.

[0009] In some embodiments, the base structure includes a hollow frame structure, one end of the laminated structure is connected to the base structure, and the other end of the laminated structure is suspended in the hollow position of the frame structure.

[0010] In some embodiments, the vibration unit comprises at least one elastic layer, and the acoustic transducing unit comprises at least a first electrode layer, a piezoelectric layer, and a second electrode layer arranged in sequence from top to bottom; wherein the at least one elastic layer is located on the upper surface of the first electrode layer or on the lower surface of the second electrode layer.

[0011] In some embodiments, the acoustic transducing unit further comprises a seed layer, and the seed layer is located on the lower surface of the second electrode layer.

[0012] In some embodiments, the first electrode layer, the piezoelectric layer, and / or the second electrode layer have a coverage area no greater than the area of the laminated structure, wherein the first electrode layer, the piezoelectric layer, and / or the second electrode layer are close to the connection between the laminated structure and the base structure.

[0013] In some embodiments, the vibration unit comprises at least one elastic layer, and the acoustic transducing unit comprises at least an electrode layer and a piezoelectric layer; the at least one elastic layer is located on the surface of the electrode layer.

[0014] In some embodiments, the electrode layer comprises a first electrode and a second electrode, wherein the first electrode is bent into a first comb-shaped structure, the second electrode is bent into a second comb-shaped structure, the first comb-shaped structure cooperates with the second comb-shaped structure to form the electrode layer, and the electrode layer is located on the upper surface or the lower surface of the piezoelectric layer.

[0015] In some embodiments, the first comb-shaped structure and the second comb-shaped structure extend along the length direction of the laminated structure. In some embodiments, the resonance frequency of the bone conduction microphone is positively correlated with the stiffness of the vibration unit.

[0016] In some embodiments, the resonance frequency of the bone conduction microphone is negatively correlated with the mass of the laminated structure.

[0017] In some embodiments, the vibration unit comprises a suspension membrane structure, and the acoustic transducing unit comprises a first electrode layer, a piezoelectric layer, and a second electrode layer arranged in sequence from top to bottom; wherein the suspension membrane structure is connected to the base structure through its peripheral side, and the acoustic transducing unit is located on the upper surface or the lower surface of the suspension membrane structure.

[0018] In some embodiments, the suspension membrane structure comprises a plurality of holes, and the plurality of holes are distributed along the outer peripheral direction and / or the inner peripheral direction of the acoustic transducing unit.

[0019] In some embodiments, the plurality of holes are circular holes, and the radius of the circular holes is 20-300 um.

[0020] In some embodiments, the shape of the plurality of holes is consistent with the shape of the acoustic transducing unit.

[0021] In some embodiments, the shape of the plurality of holes is consistent with the shape of the acoustic transducing unit.

[0022] In some embodiments, the plurality of holes are circularly distributed along the outer periphery and / or inner periphery of the acoustic transducing unit.

[0023] In some embodiments, the radius of the circle is 300um-700um.

[0024] In some embodiments, the radial distance from the edge of the effective acoustic transducing unit to the center of the plurality of holes is 50um-400um.

[0025] In some embodiments, the effective acoustic transducing unit is a circular ring structure, and the inner diameter of the acoustic transducing unit is 100um-700um.

[0026] In some embodiments, the effective acoustic transducing unit is a circular ring structure, and the outer diameter of the acoustic transducing unit is 110um-710um.

[0027] In some embodiments, the radial distance from the edge of the acoustic transducing unit to the center of the plurality of holes is 100um-400um.

[0028] In some embodiments, the acoustic transducing unit is a ring structure, and the thickness of the suspension membrane structure in the inner side region of the ring structure is greater than the thickness of the suspension membrane structure in the outer side region of the ring structure.

[0029] In some embodiments, the acoustic transducing unit is a ring structure, and the density of the suspension membrane structure in the inner side region of the ring structure is greater than the density of the suspension membrane structure in the outer side region of the ring structure.

[0030] In some embodiments, the thickness of the suspension membrane structure is 0.5um-10um.

[0031] In some embodiments, the suspension membrane structure is circular, elliptical, polygonal, or irregularly shaped.

[0032] In some embodiments, the suspension membrane structure is circular, and the radius of the suspension membrane structure is 500um-1500um.

[0033] In some embodiments, the thickness of the first electrode layer is 80nm-250nm.

[0034] In some embodiments, the thickness of the piezoelectric layer is 0.8um-5um.

[0035] In some embodiments, the second electrode layer has a thickness of 80 nm-250 nm.

[0036] In some embodiments, the vibration unit further comprises a mass element, the mass element being located on an upper surface or a lower surface of the suspended membrane structure.

[0037] In some embodiments, the acoustic transducing unit and the mass element are located on different sides of the suspended membrane structure, respectively.

[0038] In some embodiments, the acoustic transducing unit and the mass element are located on the same side of the suspended membrane structure, wherein the acoustic transducing unit is a ring structure, the ring structure being distributed along a circumferential direction of the mass element.

[0039] In some embodiments, the mass element is a cylinder, a radius of a cross section of the mass element perpendicular to a thickness direction is 100 um-700 um.

[0040] In some embodiments, the mass element is a cylinder, a thickness of the mass element is 20 um-400 um.

[0041] In some embodiments, a lead structure is provided on the suspended membrane structure, the first electrode layer and the second electrode layer being connected to the substrate structure through the lead structure.

[0042] In some embodiments, a width of the lead structure is 2 um-100 um.

[0043] In some embodiments, the lead structure comprises a first lead and a second lead, one end of the first lead being connected to the first electrode layer, the other end of the first lead being connected to the substrate structure; one end of the second lead being connected to the second electrode layer, the other end of the second lead being connected to the substrate structure.

[0044] In some embodiments, the vibration unit further comprises a mass element, the mass element being located on an upper surface or a lower surface of the suspended membrane structure; the suspended membrane structure comprises a plurality of holes, the plurality of holes being distributed along a circumferential direction of the acoustic transducing unit.

[0045] In some embodiments, a ratio of an intensity of the electrical signal to an intensity of the noise of the bone conduction microphone is 50%-100% of a ratio of the intensity of the electrical signal to the intensity of the noise being maximized.

[0046] In some embodiments, the vibration unit comprises at least one support arm and a mass element, the mass element being connected to the substrate structure through the at least one support arm.

[0047] In some embodiments, the at least one support arm comprises at least one elastic layer, and the acoustic transducing unit is located on the upper surface, lower surface or inside of the at least one support arm.

[0048] In some embodiments, the acoustic transducing unit comprises a first electrode layer, a piezoelectric layer and a second electrode layer arranged in sequence from top to bottom, and the first electrode layer or the second electrode layer is connected with the upper surface or lower surface of the at least one support arm.

[0049] In some embodiments, the mass element is located on the upper surface or lower surface of the first electrode layer or the second electrode layer.

[0050] In some embodiments, the area of the first electrode layer, the piezoelectric layer and / or the second electrode layer is not greater than the area of the support arm, and part or all of the first electrode layer, the piezoelectric layer and / or the second electrode layer covers the upper surface or lower surface of the at least one support arm.

[0051] In some embodiments, the area of the first electrode layer is not greater than the area of the piezoelectric layer, and the entire area of the first electrode layer is located on the surface of the piezoelectric layer.

[0052] In some embodiments, the first electrode layer, the piezoelectric layer and the second electrode layer of the acoustic transducing unit are close to the mass element or / and the connection between the support arm and the base structure.

[0053] In some embodiments, the at least one support arm comprises at least one elastic layer, and the at least one elastic layer is located on the upper surface or lower surface of the first electrode layer or the second electrode layer.

[0054] In some embodiments, further comprising a limiting structure located in the hollow part of the base structure, wherein the limiting structure is connected with the base structure, and the limiting structure is located above and / or below the mass element.

[0055] In some embodiments, the bone conduction sound transmission device of any one of the preceding embodiments further comprises at least one damping layer covering the upper surface, lower surface and / or inside of the laminated structure. BRIEF DESCRIPTION OF DRAWINGS

[0056] The present application will be further illustrated in the form of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting, and in these embodiments, the same numbers represent the same structures, wherein:

[0057] Figure 1 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0058] Figure 2 is Figure 1 is a sectional view of the bone conduction sound transmission device A-A shown in

[0059] Figure 3 is a structural schematic diagram of another bone conduction sound transmission device according to some embodiments of the present application;

[0060] Figure 4 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0061] Figure 5 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0062] Figure 6 is Figure 5 is a sectional view of the partial structure of the bone conduction sound transmission device shown in

[0063] Figure 7 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0064] Figure 8 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0065] Figure 9 is Figure 8 is a sectional view of the bone conduction sound transmission device C-C shown in

[0066] Figure 10 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0067] Figure 11 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0068] Figure 12 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0069] Figure 13 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0070] Figure 14 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0071] Figure 15 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0072] Figure 16is a structural schematic diagram of a bone conduction sound device according to some embodiments of the present application;

[0073] Figure 17 is a frequency response curve of the natural frequency advance of the laminated structure according to some embodiments of the present application;

[0074] Figure 18 is a frequency response curve of the bone conduction sound device with and without damping structure layer according to some embodiments of the present application;

[0075] Figure 19 is a cross-sectional view of a bone conduction sound device according to some embodiments of the present application;

[0076] Figure 20 is a cross-sectional view of a bone conduction sound device according to some embodiments of the present application;

[0077] Figure 21 is a cross-sectional view of a bone conduction sound device according to some embodiments of the present application;

[0078] Figure 22 is a schematic diagram of a suspension membrane structure and a hole in a bone conduction sound device according to some embodiments of the present application;

[0079] Figure 23 is a schematic diagram of a suspension membrane structure and a hole in another bone conduction sound device according to some embodiments of the present application;

[0080] Figure 24 is a schematic diagram of a suspension membrane structure and a hole in another bone conduction sound device according to some embodiments of the present application;

[0081] Figure 25 is a schematic diagram of a suspension membrane structure and a hole in another bone conduction sound device according to some embodiments of the present application;

[0082] Figure 26 is a schematic diagram of a suspension membrane structure and a hole in another bone conduction sound device according to some embodiments of the present application;

[0083] Figure 27 is a schematic diagram of an acoustic transducing unit in a bone conduction sound device according to some embodiments of the present application;

[0084] Figure 28 is a schematic diagram of a lead structure in a bone conduction sound device according to some embodiments of the present application;

[0085] Figure 29 is a schematic diagram of a lead structure in another bone conduction sound device according to some embodiments of the present application;

[0086] Figure 30 isFigure 7 a cross-sectional view of a partial structure of the bone conduction microphone device shown in FIG. 1;

[0087] Figures 31A-31C is a schematic diagram of different mass elements in a bone conduction microphone device according to some embodiments of the present application;

[0088] Figures 32A-32D is a schematic diagram of different acoustic transduction units in a bone conduction microphone device according to some embodiments of the present application;

[0089] Figures 33A-33B is a schematic diagram of different lead structures in a bone conduction microphone device according to some embodiments of the present application;

[0090] Figure 34 is a schematic diagram of lead structures in another bone conduction microphone device according to some embodiments of the present application;

[0091] Figure 35 is a schematic diagram of a structure of a bone conduction microphone device according to some embodiments of the present application;

[0092] Figure 36 is Figure 35 a cross-sectional view of a partial structure of the bone conduction microphone device shown in FIG. 1;

[0093] Figure 37 is a resonance frequency curve of a bone conduction microphone device according to some embodiments of the present application; and

[0094] Figure 38 is a resonance frequency curve of another bone conduction microphone device according to some embodiments of the present application. DETAILED DESCRIPTION

[0095] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some examples or embodiments of the present application, and for those skilled in the art, the present application can also be applied to other similar scenarios without creative labor on the basis of these drawings. Unless it is obvious from the language environment or otherwise stated, the same reference numbers in the drawings represent the same structure or operation. It should be understood that the drawings are for the purpose of illustration and description only, and are not intended to limit the scope of the present application. It should be understood that the drawings are not drawn to scale.

[0096] It should be understood that, for ease of description of the present application, the terms "center", "upper surface", "lower surface", "upper", "lower", "top", "bottom", "inner", "outer", "axial", "radial", "periphery", "exterior", and the like indicate positional relationships based on the positional relationships shown in the drawings, and do not indicate that the devices, components, or units referred to must have a particular positional relationship, and should not be understood as limiting the present application.

[0097] It should be understood that the "system", "device", "unit", and / or "module" used herein is a method for distinguishing different components, elements, parts, portions, or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

[0098] As shown in the present application and claims, unless the context clearly indicates otherwise, the words "one", "a", "an", and / or "the" do not necessarily refer to the singular, but can also include the plural. Generally, the terms "comprise" and "include" only indicate the inclusion of the steps and elements explicitly identified, and these steps and elements do not constitute an exclusive list, and the method or device can also include other steps or elements.

[0099] Flowcharts are used in the present application to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or subsequent operations are not necessarily performed in sequence. Instead, each step can be processed in reverse order or simultaneously. Meanwhile, other operations can be added to these processes, or one or more steps can be removed from these processes.

[0100] In describing the bone conduction related technology in the present application, the description of "bone conduction microphone", "bone conduction sound receiving device", "microphone device", or "bone conduction microphone" will be used, which is only one form of bone conduction application, and the bone conduction devices referred to by the above different descriptions are equivalent. For ease of illustration, the use and application process of the sound emitting unit are described below with the bone conduction sound receiving device as an example. It should be noted that the above description is provided only for illustrative purposes and is not intended to limit the scope of the present application.

[0101] Some embodiments of the present application provide a bone conduction sound transmission device, which can include a base structure and a laminated structure. In some embodiments, the base structure can be a regular or irregular three-dimensional structure with a hollow portion inside, for example, a hollow frame structure, including but not limited to a regular shape such as a rectangular frame, a circular frame, a regular polygonal frame, and any irregular shape. The laminated structure can be located in the hollow portion of the base structure or at least partially suspended above the hollow portion of the base structure. In some embodiments, at least part of the laminated structure is connected to the base structure by physical means. Here, "connected" can be understood as, after the laminated structure and the base structure are respectively prepared, the laminated structure and the base structure are fixedly connected by welding, riveting, clamping, bolting, or the like, or, during the preparation process, the laminated structure is deposited on the base structure by physical deposition (e.g., physical vapor deposition) or chemical deposition (e.g., chemical vapor deposition). In some embodiments, at least part of the laminated structure can be fixed to the upper surface or the lower surface of the base structure, and at least part of the laminated structure can also be fixed to the side wall of the base structure. For example, the laminated structure can be a cantilever beam, which can be a plate-like structure, one end of the cantilever beam is connected to the upper surface, the lower surface of the base structure, or the side wall where the hollow portion of the base structure is located, and the other end of the cantilever beam is not connected or in contact with the base structure, so that the other end of the cantilever beam is suspended in the hollow portion of the base structure. For another example, the laminated structure can include a diaphragm layer (also referred to as a suspension membrane structure), the suspension membrane structure is fixedly connected to the base structure, and the laminated structure is arranged on the upper surface or the lower surface of the suspension membrane structure. For another example, the laminated structure can include a mass element and one or more support arms, the mass element is fixedly connected to the base structure through the one or more support arms, one end of the support arm is connected to the base structure, and the other end of the support arm is connected to the mass element, so that part of the mass element and the support arm is suspended in the hollow portion of the base structure. It should be noted that "located in the hollow portion of the base structure" or "suspended in the hollow portion of the base structure" in the present application can mean suspended inside, below, or above the hollow portion of the base structure. In some embodiments, the laminated structure can include a vibration unit and an acoustic transduction unit. Specifically, the base structure can generate vibration based on an external vibration signal, the vibration unit deforms in response to the vibration of the base structure, and the acoustic transduction unit generates an electric signal based on the deformation of the vibration unit. It should be noted that the description of the vibration unit and the acoustic transduction unit here is only for the purpose of conveniently introducing the working principle of the laminated structure, and does not limit the actual composition and structure of the laminated structure. In fact, the vibration unit can not be necessary, and its function can be fully realized by the acoustic transduction unit. For example, after making certain changes to the structure of the acoustic transduction unit, the acoustic transduction unit can directly generate an electric signal in response to the vibration of the base structure.

[0102] The vibration unit refers to a part of the laminated structure that is prone to deformation under the action of external force or inertia. The vibration unit can be used to transmit the deformation caused by external force or inertia to the acoustic transducing unit. In some embodiments, the vibration unit and the acoustic transducing unit overlap to form a laminated structure. The acoustic transducing unit can be located on the upper layer of the vibration unit, and the acoustic transducing unit can also be located on the lower layer of the vibration unit. For example, when the laminated structure is a cantilever beam structure, the vibration unit can include at least one elastic layer, and the acoustic transducing unit can include a first electrode layer, a piezoelectric layer and a second electrode layer arranged in order 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 can be deformed 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 can collect the electrical signal. For another example, the vibration unit can also be a suspended membrane structure. The density of a specific region of the suspended membrane structure can be changed, or holes can be punched in the suspended membrane structure or a counterweight (also called a mass element) can be arranged on the suspended membrane structure, so that the suspended membrane structure near the acoustic transducing unit is more prone to deformation under the action of external force, thereby driving the acoustic transducing unit to generate an electrical signal. For another example, the vibration unit can include at least one support arm and a mass element. The mass element is suspended in the hollow part of the base structure by the support arm. When the base structure vibrates, the support arm and the mass element of the vibration unit move relative to the base structure. The support arm is deformed and acts on the acoustic transducing unit to generate an electrical signal.

[0103] The acoustic transducing unit refers to the part of the laminated structure that converts the deformation of the vibration unit into an electrical signal. In some embodiments, the acoustic transducing unit can include at least two electrode layers (e.g., a first electrode layer and a second electrode layer), a piezoelectric layer, which can be located between the first electrode layer and the second electrode layer. The piezoelectric layer refers to a structure that can generate a voltage across its two end faces when subjected to an external force. In some embodiments, the piezoelectric layer can be a piezoelectric polymer thin film obtained by a deposition process (e.g., magnetron sputtering, MOCVD) of a semiconductor. In embodiments of the present specification, 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). In some embodiments, the material of the piezoelectric layer can include a piezoelectric thin film material, which can be a thin film material (e.g., AIN thin film material) made by a deposition process (e.g., magnetron sputtering deposition process). In other embodiments, the material of the piezoelectric layer can include piezoelectric crystal materials and piezoelectric ceramic materials. The piezoelectric crystal refers to a piezoelectric single crystal. In some embodiments, the piezoelectric crystal material can include quartz, zinc blende, spherulite, tourmaline, red zinc ore, GaAs, barium titanate and its derivative structure crystal, KH2PO4, NaKC4H4O6·4H2O (Rochelle salt), etc., or any combination thereof. The piezoelectric ceramic material refers to a piezoelectric polycrystal obtained by the random collection of microcrystalline grains through solid-phase reaction and sintering between different material powders. In some embodiments, the piezoelectric ceramic material can include barium titanate (BT), lead zirconate titanate (PZT), lead barium lithium niobate (PBLN), modified lead titanate, aluminum nitride (AIN), zinc oxide (ZnO), or any combination thereof. In some embodiments, the piezoelectric layer material can also be a piezoelectric polymer material, such as polyvinylidene fluoride (PVDF), etc.

[0104] In some embodiments, the base structure and the laminated structure can be located in a housing of the bone conduction sound pickup device, the base structure is fixedly connected to an inner wall of the housing, and the laminated structure is carried by the base structure. When the housing of the bone conduction sound pickup device is vibrated by an external force (for example, the vibration of the face of a human body when speaking drives the vibration of the housing), the vibration of the housing drives the vibration of the base structure. Further, when the vibration unit deforms, the piezoelectric layer of the acoustic transducing unit generates a potential difference (voltage) under the deformation stress of the vibration unit, and at least two electrode layers (for example, a first electrode layer and a second electrode layer) respectively located on the upper surface and the lower surface of the piezoelectric layer in the acoustic transducing unit can collect the potential difference to convert the external vibration signal into an electrical signal. By way of example only, the bone conduction sound pickup device described in the embodiments of the present application can be applied to earphones (for example, bone conduction earphones or air conduction earphones), glasses, virtual reality devices, helmets, etc. The bone conduction sound pickup device can be placed near the head (for example, the face), the neck, the ear, and the top of the head of a human body, etc. The bone conduction sound pickup device can pick up the vibration signal of the bone 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 of the bone conduction sound pickup device. In some embodiments, the base structure can also be part of the housing of the bone conduction sound pickup device.

[0105] The bone conduction sound receiving device (or bone conduction microphone) receives external vibration signals, converts the vibration signals into electrical signals by using a laminated structure (including an acoustic transducing unit and a vibration unit), and outputs the electrical signals after processing by a rear-end circuit. Resonance can also be referred to as "sympathetic vibration". Under the action of external vibration signals, when the frequency of external force is the same as or very close to the natural oscillation frequency of the system, the phenomenon that the amplitude sharply increases is called resonance, and the frequency at which resonance occurs is called "resonant frequency". The bone conduction sound receiving device has a natural frequency, and when the frequency of the external vibration signal is close to the natural frequency, the laminated structure will produce a larger amplitude, thereby outputting a larger electrical signal. Therefore, the response of the bone conduction sound receiving device to external vibration will show a resonance peak near the natural frequency. Therefore, the resonant frequency of the bone conduction sound receiving device is basically equal in value to the natural frequency. In some embodiments, the natural frequency of the bone conduction sound receiving device can refer to the natural frequency of the laminated structure. In some embodiments, the natural frequency of the laminated structure is in the range of 4 kHz-4.5 kHz. In some embodiments, since the human bone conduction signal decays rapidly after 1 kHz, it is desirable to adjust the resonant frequency of the bone conduction sound receiving device (or the natural frequency of the laminated structure) to the range of 1 kHz-5 kHz of the speech frequency band. In some embodiments, the resonant frequency of the bone conduction sound receiving device can be adjusted to the range of 2 kHz-5 kHz of the speech frequency band. In some embodiments, the resonant frequency of the bone conduction sound receiving device is 2.5 kHz-4.5 kHz. In some embodiments, the resonant frequency of the bone conduction sound receiving device can be adjusted to the range of 3 kHz-4.5 kHz of the speech frequency band. In some embodiments, the resonant frequency of the bone conduction sound receiving device can be adjusted to the range of 2.5 kHz-3.5 kHz of the speech frequency band. According to the adjustment of the above resonant frequency range, the resonance peak of the bone conduction sound receiving device can be located in the range of 2.5 kHz-4.5 kHz of the speech frequency band, thereby improving the sensitivity of the bone conduction sound receiving device to respond to the vibration of the speech frequency band (for example, the frequency range before the resonance peak, i.e. 20 Hz-5 kHz).

[0106] Since the bone conduction sound transmission device can be equivalent to a mass-spring-damper system model, the bone conduction sound transmission device can be equivalent to a mass-spring-damper system doing forced vibration under the action of an exciting force when it works, and its vibration law conforms to the law of the mass-spring-damper system. Therefore, the resonance frequency of the bone conduction sound transmission device is related to the equivalent stiffness and the equivalent mass of its internal components (for example, the vibration unit or the laminated structure), that is, the resonance frequency of the bone conduction sound transmission device is positively correlated with the equivalent stiffness of its internal components and negatively correlated with the equivalent mass of its internal components. Wherein, the equivalent stiffness is the stiffness of the bone conduction sound transmission device after being equivalent to the mass-spring-damper system model, and the equivalent mass is the mass of the bone conduction sound transmission device after being equivalent to the mass-spring-damper system model. Therefore, in order to adjust the resonance frequency (or natural frequency) of the bone conduction sound transmission device, it is necessary to adjust the equivalent stiffness and the equivalent mass of the vibration unit or the laminated structure.

[0107] For the bone conduction sound transmission device, it can be equivalent to a mass-spring-damper system model doing forced vibration under the action of an exciting external force when it works, and its vibration law conforms to the law of the mass-spring-damper system model. Under the action of the exciting external force, the influencing parameters of the resonance frequency f0may include but are not limited to the system equivalent stiffness k, the system equivalent mass m, and the system equivalent relative damping coefficient (damping ratio) ζ. In some embodiments, the system equivalent stiffness k is positively correlated with the resonance frequency f0on the system of the bone conduction sound transmission device, the system equivalent mass m is negatively correlated with the resonance frequency f0on the system of the bone conduction sound transmission device, and the system equivalent relative damping coefficient (damping ratio) ζ is negatively correlated with the resonance frequency f0on the system of the bone conduction sound transmission device. In some embodiments, In some embodiments, the frequency response satisfies the following formula (1):

[0108]

[0109] Wherein: f0is the resonance frequency on the system of the bone conduction sound transmission device, k is the system equivalent stiffness, m is the system equivalent mass, and ζ is the system equivalent relative damping coefficient (damping ratio).

[0110] For most bone conduction sound transmission devices, especially piezoelectric bone conduction sound transmission devices, the system equivalent relative damping coefficient ζ is usually very small, and the resonance frequency of the system is mainly affected by the equivalent stiffness and the equivalent mass. For example, as shown in the bone conduction sound transmission device of Figure 5 The suspension membrane structure 530 provides spring and damping effects and mass effects for the vibration system. Therefore, the suspension membrane structure 530 mainly affects the system equivalent stiffness k, and also affects the system equivalent mass m. For example, as shown in the bone conduction sound transmission device of Figure 7The suspension membrane structure 730 of the illustrated bone conduction sound transmission device provides spring and damping effects for the vibration system, and the mass element 740 provides mass effect. Therefore, the suspension membrane structure 730 mainly affects the equivalent stiffness k of the system, while also affecting the equivalent mass m of the system; the mass element 740 mainly affects the equivalent mass m of the system, while also affecting the equivalent stiffness k of the system. For a bone conduction sound transmission device with a relatively complex structure, it is difficult to solve the resonant frequency f0 of the bone conduction sound transmission device by theory. A finite element simulation tool can be used to solve the frequency response of the bone conduction sound transmission device by establishing a model of the corresponding structure and parameters. In some embodiments, the resonant frequency f0 of the bone conduction sound transmission device can be adjusted by selecting different materials to make the electrode layer (including the first electrode layer and the second electrode layer), the piezoelectric layer, the elastic layer, and the mass element, etc. described below. In some embodiments, the resonant frequency f0 of the bone conduction sound transmission device can be adjusted by designing the structure of the bone conduction sound transmission device, such as the structure of the support arm plus the mass element, the structure of the cantilever beam, the structure of the perforated suspension membrane, and the structure of the suspension membrane plus the mass element. In some embodiments, the resonant frequency f0 of the bone conduction sound transmission device can be adjusted by designing the size of different components, such as the length, width, thickness, etc. of the support arm, mass element, cantilever beam, suspension membrane, etc.

[0111] In some embodiments, the equivalent stiffness and the equivalent mass can be adjusted by changing the structural parameters of the vibration unit and the acoustic transduction unit, so that the natural frequency of the laminated structure is reduced to the range of the speech frequency band. For example, holes can be provided on the vibration unit to adjust the equivalent stiffness of the vibration unit. For another example, a mass element can be provided in the vibration unit to adjust the equivalent mass of the laminated unit. For another example, a support arm can be provided in the vibration unit to adjust the equivalent stiffness of the laminated unit. More details about the adjustment of the structural parameters of the vibration unit and the acoustic transduction unit can be referred to the description below, which will not be repeated here.

[0112] The signal-to-noise ratio (SNR) refers to the ratio of signal to noise in an electronic device or electronic system. In a bone conduction sound transmission device, the larger the signal-to-noise ratio, the greater the intensity of the electrical signal and the smaller the noise of the bone conduction sound transmission device, the better the effect of the bone conduction sound transmission device. Therefore, the signal-to-noise ratio is a very important parameter in the design process of the bone conduction sound transmission device. In some embodiments, the signal-to-noise ratio SNR is positively correlated with the sensitivity v s of the bone conduction sound transmission device, and the signal-to-noise ratio SNR is negatively correlated with the noise floor v ntrms of the bone conduction sound transmission device. In some embodiments, the signal-to-noise ratio SNR is positively correlated with the sensitivity v s of the bone conduction sound transmission device, and the signal-to-noise ratio SNR is negatively correlated with the noise floor v ntrms of the bone conduction sound transmission device. In some embodiments, the signal-to-noise ratio SNR is positively correlated with are positively correlated. In some embodiments, the signal-to-noise ratio SNR of the bone conduction sound transmission device can be calculated according to formula (2) as follows:

[0113]

[0114] wherein v s is the sensitivity of the bone conduction sound transmission device. v s is positively correlated with the piezoelectric constant and the internal stress of the piezoelectric layer (such as the first piezoelectric layer), wherein the piezoelectric constant is related to the material of the piezoelectric layer, and the internal stress of the piezoelectric layer is related to the structure of the bone conduction sound transmission device and the external load. In some embodiments, the sensitivity value v s of the structure of different bone conduction sound transmission devices under the corresponding external load can be solved by means of finite element numerical calculation method after the model is established. ntrms v ntrms is the noise floor of the bone conduction sound transmission device, which can be determined by parameters such as the noise floor value v narms of the amplification circuit (ASIC) and the noise floor value v nsrms of the transducer (acoustic transduction unit). The noise floor v ntrms of the bone conduction sound transmission device is positively correlated with the noise floor value v narms of the amplification circuit (ASIC) and the noise floor value v nsrms of the transducer. narms is the noise floor value of the amplification circuit (ASIC), which can be calculated during the design of the amplification circuit or obtained from the manufacturer. In some embodiments, the noise floor v ntrms of the bone conduction sound transmission device can be related to parameters such as the dielectric loss tanδ of the piezoelectric layer (such as the first piezoelectric layer), the dielectric constant ε r of the piezoelectric layer (such as the first piezoelectric layer), the thickness d of the piezoelectric layer (such as the first piezoelectric layer), the area S of the effective acoustic transduction unit of the bone conduction sound transmission device, the low-frequency cutoff frequency f0 of the noise floor of the bone conduction sound transmission device, and the high-frequency cutoff frequency f1 of the noise floor of the bone conduction sound transmission device.

[0115] In some embodiments, the noise floor v ntrms of the bone conduction sound transmission device can be positively correlated with parameters such as the dielectric constant ε r of the piezoelectric layer (such as the first piezoelectric layer), the thickness d of the piezoelectric layer (such as the first piezoelectric layer), and the high-frequency cutoff frequency f1 of the noise floor of the bone conduction sound transmission device. The noise floor v ntrms of the bone conduction sound transmission device can be negatively correlated with parameters such as the area S of the effective acoustic transduction unit of the bone conduction sound transmission device, the low-frequency cutoff frequency f0 of the noise floor of the bone conduction sound transmission device, and the dielectric loss tanδ of the piezoelectric layer (such as the first piezoelectric layer). In some embodiments, the noise floor v ntrmsThe formula (3) can be calculated as follows:

[0116] v ntrms = f(v nsrms , v narms ) = f(tan δ, ε r , d, S, f1, f0, v narms , ASIC gain) (3)

[0117] wherein the ASIC gain is the gain of the amplification circuit, which can be calculated during the design of the amplification circuit or obtained from the manufacturer. The tan δ is the dielectric loss of the piezoelectric layer (e.g. the first piezoelectric layer), the ε r is the dielectric constant of the piezoelectric layer (e.g. the first piezoelectric layer), the d is the thickness of the piezoelectric layer (e.g. the first piezoelectric layer), the S is the area of the effective acoustic transducing unit of the bone conduction sound device, the f0 is the low frequency cutoff frequency of the background noise of the bone conduction sound device, and the f1 is the high frequency cutoff frequency of the background noise of the bone conduction sound device.

[0118] The formula (3) is substituted into the formula (2) to obtain the formula (4) for determining the signal-to-noise ratio SNR of the bone conduction sound device:

[0119]

[0120] The meanings of the parameters in the formula (4) are explained above. In the above formula (4), the dielectric loss tan δ of the piezoelectric material and the dielectric constant ε r of the piezoelectric material are related to the material of the piezoelectric layer (e.g. the first piezoelectric layer). As can be seen from the above formula (4), the signal-to-noise ratio is related to the area of the effective acoustic transducing unit, the thickness of the piezoelectric layer (e.g. the first piezoelectric layer), the material of the piezoelectric layer (e.g. the first piezoelectric layer), and the sensitivity (which is affected by the material and structure of the bone conduction sound device).

[0121] According to the SNR solving formula of the bone conduction microphone device proposed in the patent, the materials of the electrode layer (the first electrode layer and the second electrode layer), the piezoelectric layer (the first piezoelectric layer and the second piezoelectric layer), the elastic layer, and the mass element are designed, and the structure of the bone conduction microphone device is designed, so that the design scheme can meet the range requirement of the resonance frequency f0 while maximizing the SNR of the bone conduction microphone device. For example, the design is a perforated suspension membrane structure, a suspension membrane structure plus mass element structure, a cantilever beam structure, or a support arm plus mass element structure, etc., and the size of different components of the bone conduction microphone device is designed, such as the size of the suspension membrane structure, the number and size of the holes on the suspension membrane structure, the size and thickness of the mass element, and the area of the effective acoustic transduction unit, etc. For example only, in the perforated suspension membrane structure, the stiffness and mass of the suspension membrane structure can be adjusted by designing the materials, sizes, and number and size of the holes of the acoustic transduction unit and each part of the suspension membrane structure, so that stress concentration occurs at the acoustic transduction unit. The stress concentration at the acoustic transduction unit can increase the output electric signal of the bone conduction microphone device, thereby maximizing the output sensitivity and SNR of the bone conduction microphone device. For example only, in the suspension membrane structure plus mass element structure, the stiffness of the suspension membrane structure and the mass of the mass element can be adjusted by designing the materials and sizes of the acoustic transduction unit, the suspension membrane structure, and each part of the mass element, so that stress concentration occurs at the acoustic transduction unit. The stress concentration at the acoustic transduction unit can increase the output electric signal of the bone conduction microphone device, thereby maximizing the output sensitivity and SNR of the bone conduction microphone device. In the above design process, in order to ensure that the designed bone conduction microphone device has good reliability, the SNR can be adjusted by adjusting the materials, structure, and size of different components, so that the SNR is less than the maximum SNR, for example, the design SNR is 80%-100% of the maximum SNR; the design SNR is 50%-100% of the maximum SNR; the design SNR is 20%-100% of the maximum SNR.

[0122] Figure 1 is a structural schematic diagram of a bone conduction microphone device according to some embodiments of the present application. Figure 2 is Figure 1 is a sectional view of the bone conduction microphone device A-A shown in

[0123] As shown in Figure 1 and Figure 2 , the bone conduction microphone device 100 can include a base structure 110 and a laminated structure, wherein at least part of the laminated structure is connected with the base structure 110. The base structure 110 can be a frame structure body with an internal cavity, and part of the laminated structure (for example, the end of the laminated structure away from the connection between the laminated structure and the base structure 110) can be located in the cavity of the frame structure body. It should be noted that the frame structure body is not limited toFigure 1 The frame structure can be a rectangular prism as shown in FIG. 1, and in some embodiments, the frame structure can be a prism, a cylinder, or other regular or irregular structure. In some embodiments, the laminated structure can be fixedly connected to the base structure 110 in the form of a cantilever beam. Further, the laminated structure can include a fixed end and a free end, wherein the fixed end of the laminated structure is fixedly connected to the frame structure, and the free end of the laminated structure is not connected to or in contact with the frame structure, so that the free end of the laminated structure can be suspended in the hollow portion of the frame structure. In some embodiments, the fixed end of the laminated structure can be connected to the upper surface, the lower surface, or the side wall where the hollow portion of the base structure 110 is located. In some embodiments, the side wall where the hollow portion of the base structure 110 is located can also be provided with a mounting groove adapted to the fixed end of the laminated structure, so that the fixed end of the laminated structure is connected to the base structure 110. In order to improve the stability between the laminated structure and the base structure 110, in some embodiments, the laminated structure can include a connecting seat 140. For example, as shown in FIG. 1, the connecting seat 140 is fixedly connected to the surface of the laminated structure. In some embodiments, the fixed end of the connecting seat 140 can be located on the upper surface or the lower surface of the base structure 110. In some embodiments, the fixed end of the connecting seat 140 can also be located on the side wall where the hollow portion of the base structure 110 is located. For example, the side wall where the hollow portion of the base structure 110 is located is provided with a mounting groove adapted to the fixed end, so that the fixed end of the laminated structure is connected to the base structure 110 through the mounting groove. Here, "connection" can be understood as fixing the laminated structure and the base structure 110 by welding, riveting, bonding, bolting, clamping, or the like after the laminated structure and the base structure 110 are respectively prepared; or in the preparation process, the laminated structure is deposited on the base structure 110 by physical deposition (e.g., physical vapor deposition) or chemical deposition (e.g., chemical vapor deposition). In some embodiments, the connecting seat 140 can be a structure independent of the laminated structure or integrally formed with the laminated structure. Figure 1

[0124] In some embodiments, the laminated structure can include an acoustic transduction unit 120 and a vibration unit 130. The vibration unit 130 refers to the portion of the laminated structure that can elastically deform, and the acoustic transduction unit 120 refers to the portion of the laminated structure that converts the deformation of the vibration unit 130 into an electrical signal. In some embodiments, the vibration unit 130 can be located on the upper surface or the lower surface of the acoustic transduction unit 120. In some embodiments, the vibration unit 130 can include at least one elastic layer. For example, as shown in FIG. 1, the vibration unit 130 includes an elastic layer 131 and a piezoelectric layer 132. The elastic layer 131 can be made of a material with elastic properties, such as a polymer, and the piezoelectric layer 132 can be made of a piezoelectric material, such as lead zirconate titanate (PZT). In some embodiments, the vibration unit 130 can include a plurality of elastic layers and a plurality of piezoelectric layers. For example, as shown in FIG. 1, the vibration unit 130 includes an elastic layer 131, a piezoelectric layer 132, an elastic layer 133, and a piezoelectric layer 134. In some embodiments, the vibration unit 130 can include a plurality of elastic layers and a plurality of piezoelectric layers. For example, as shown in FIG. 1, the vibration unit 130 includes an elastic layer 131, a piezoelectric layer 132, an elastic layer 133, and a piezoelectric layer 134. Figure 1 ​The illustrated vibration unit 130 can include a first elastic layer 131 and a second elastic layer 132 arranged in sequence from top to bottom. The first elastic layer 131 and the second elastic layer 132 can be plate-shaped structures made of a semiconductor material. In some embodiments, the semiconductor material can include silicon dioxide, silicon nitride, gallium nitride, zinc oxide, silicon carbide, etc. In some embodiments, the materials of the first elastic layer 131 and the second elastic layer 132 can be the same or different. In some embodiments, the acoustic transducing unit 120 at least includes a first electrode layer 121, a piezoelectric layer 122, and a second electrode layer 123 arranged in sequence from top to bottom, wherein an elastic layer (e.g., the first elastic layer 131 and the second elastic layer 132) can be located on the upper surface of the first electrode layer 121 or the lower surface of the second electrode layer 123. The piezoelectric layer 122 can generate a voltage (potential difference) based on the piezoelectric effect under the deformation stress of the vibration unit 130 (e.g., the first elastic layer 131 and the second elastic layer 132), and the first electrode layer 121 and the second electrode layer 123 can lead out the voltage (electric signal). In some embodiments, the material of the piezoelectric layer can include a piezoelectric thin film material, which can be a thin film material (e.g., AIN thin film material) made by a deposition process (e.g., a magnetron sputtering deposition process). In other embodiments, the material of the piezoelectric layer 122 can include a piezoelectric crystal material and a piezoelectric ceramic material. The piezoelectric crystal material refers to a piezoelectric single crystal. In some embodiments, the piezoelectric crystal material can include quartz, zinc blende, tetraborite, tourmaline, red zinc ore, GaAs, barium titanate and its derivative structure crystal, KH2PO4, NaKC4H4O6·4H2O (Rochelle salt), etc., or any combination thereof. The piezoelectric ceramic material can refer to a piezoelectric polycrystal formed by the random collection of microcrystalline grains obtained by solid-phase reaction and sintering between different material powders. In some embodiments, the piezoelectric ceramic material can include barium titanate (BT), lead zirconate titanate (PZT), lead barium lithium niobate (PBLN), modified lead titanate aluminum nitride (AIN), zinc oxide (ZnO), etc., or any combination thereof. In some embodiments, the piezoelectric layer material can also be a piezoelectric polymer material, such as polyvinylidene fluoride (PVDF), etc. In some embodiments, the first electrode layer 121 and the second electrode layer 123 are conductive material structures. Exemplary conductive materials can include metals, alloy materials, metal oxide materials, graphene, etc., or any combination thereof. In some embodiments, the metals and alloy materials can include nickel, iron, lead, platinum, titanium, copper, molybdenum, zinc, or any combination thereof. In some embodiments, the alloy materials can include copper-zinc alloy, copper-tin alloy, copper-nickel-silicon alloy, copper-chromium alloy, copper-silver alloy, etc., or any combination thereof. In some embodiments, the metal oxide material can include RuO2, MnO2, PbO2, NiO, etc., or any combination thereof.

[0125] When the relative movement between the laminated structure and the base structure 110 occurs, the deformation degree of the vibration unit 130 (for example, the first elastic layer 131 or the second elastic layer 132) in the laminated structure at different positions is different, that is, the deformation stress of the piezoelectric layer 122 of the acoustic transducing unit 120 generated by the vibration unit 130 at different positions is different. In order to improve the sensitivity of the bone conduction sound device, in some embodiments, the acoustic transducing unit 120 can be arranged only at the position where the deformation degree of the vibration unit 130 is large, so as to improve the signal-to-noise ratio of the bone conduction sound device 100. Correspondingly, the area of the first electrode layer 121, the piezoelectric layer 122, and / or the second electrode layer 123 of the acoustic transducing unit 120 can be not greater than the area of the vibration unit 130. In some embodiments, in order to further improve the signal-to-noise ratio of the bone conduction sound device 100, the area of the acoustic transducing unit 120 covered on the vibration unit 130 is not greater than 1 / 2 of the area of the vibration unit 130. Preferably, the area of the acoustic transducing unit 120 covered on the vibration unit 130 is not greater than 1 / 3 of the area of the vibration unit 130. Further preferably, the area of the acoustic transducing unit 120 covered on the vibration unit 130 is not greater than 1 / 4 of the area of the vibration unit 130. Further, in some embodiments, the position of the acoustic transducing unit 120 can be close to the connection between the laminated structure and the base structure 110. The deformation degree of the vibration unit 130 (for example, the elastic layer) generated by the external force close to the connection between the laminated structure and the base structure 110 is large, and the deformation stress of the acoustic transducing unit 120 close to the connection between the laminated structure and the base structure 110 is also large. Arranging the acoustic transducing unit 120 in the area with large deformation stress can improve the signal-to-noise ratio of the bone conduction sound device 100 on the basis of improving the sensitivity of the bone conduction sound device 100. It should be noted that here the acoustic transducing unit 120 can be close to the connection between the laminated structure and the base structure 110 is relative to the free end of the laminated structure, that is, the distance from the acoustic transducing unit 120 to the connection between the laminated structure and the base structure 110 is less than the distance from the acoustic transducing unit 120 to the free end. In some embodiments, the sensitivity and signal-to-noise ratio of the bone conduction sound device 100 can be improved only by adjusting the area and position of the piezoelectric layer 122 in the acoustic transducing unit 120. For example, the first electrode layer 121 and the second electrode layer 123 are all covered or partially covered on the surface of the vibration unit 130, and the area of the piezoelectric layer 122 can be not greater than the area of the first electrode layer 121 or the second electrode layer 123. In some embodiments, the area of the piezoelectric layer 122 covered on the first electrode layer 121 or the second electrode layer 123 is not greater than 1 / 2 of the area of the first electrode layer 121 or the second electrode layer 123. Preferably, the area of the piezoelectric layer 122 covered on the first electrode layer 121 or the second electrode layer 123 is not greater than 1 / 3 of the area of the first electrode layer 121 or the second electrode layer 123.Further preferably, the piezoelectric layer 122 covers an area of the first electrode layer 121 or the second electrode layer 123 that is no more than 1 / 4 of the area of the first electrode layer 121 or the second electrode layer 123. In some embodiments, in order to prevent the problem of short circuiting caused by the first electrode layer 121 and the second electrode layer 123 being connected, the area of the first electrode layer 121 can be smaller than the area of the piezoelectric layer 122 or the second electrode layer 123. For example, the piezoelectric layer 122, the second electrode layer 123, and the vibration unit 130 have the same area, and the area of the first electrode layer 121 is smaller than the area of the vibration unit 130 (e.g., the elastic layer), the piezoelectric layer 122, or the second electrode layer 123. In this case, the entire area of the first electrode layer 121 is located on the surface of the piezoelectric layer 122, and the edge of the first electrode layer 121 can have a certain spacing from the edge of the piezoelectric layer 122, so that the first electrode layer 121 avoids the area with poor material quality at the edge of the piezoelectric layer 122, thereby further improving the signal-to-noise ratio of the bone conduction sound device 100.

[0126] In some embodiments, in order to increase the output electrical signal and improve the signal-to-noise ratio of the bone conduction sound device, the piezoelectric layer 122 can be located on one side of the neutral layer of the laminated structure. The neutral layer refers to a planar layer in the laminated structure that has approximately zero deformation stress when deformation occurs. In some embodiments, the signal-to-noise ratio of the bone conduction sound device can also be improved by adjusting (e.g., increasing) the stress and stress gradient of the piezoelectric layer 122 per unit thickness. In some embodiments, the signal-to-noise ratio and sensitivity of the bone conduction sound device 100 can also be improved by adjusting the shape, thickness, material, and size (e.g., length, width, thickness) of the acoustic transducer unit 120 (e.g., the first electrode layer 121, the piezoelectric layer 122, the second electrode layer 123) and the vibration unit 130 (e.g., the first elastic layer 131, the second elastic layer 132).

[0127] In some embodiments, in order to control the warping deformation problem of the laminated structure, it is necessary to balance the stress of each layer in the laminated structure, so that the upper and lower parts of the neutral layer of the cantilever beam receive the same type of stress (e.g., tensile stress, compressive stress) and the same size. For example, when the piezoelectric layer 122 is an AIN material layer, the piezoelectric layer 122 is arranged on one side of the neutral layer of the cantilever beam, and the AIN material layer is usually under tensile stress, and the overall stress of the elastic layer on the other side of the neutral layer should also be under tensile stress.

[0128] In some embodiments, the acoustic transducing unit 120 can further include a seed layer (not shown in the figure) for providing a good growth surface structure for other layers, which is located at the lower surface of the second electrode layer 123. In some embodiments, the material of the seed layer can be the same as that of the piezoelectric layer 122. For example, when the material of the piezoelectric layer 122 is AlN, the material of the seed layer is also AlN. It should be noted that when the acoustic transducing unit 120 is located at the lower surface of the second electrode layer 123, the seed layer can be located at the upper surface of the first electrode layer 121. Further, when the acoustic transducing unit 120 includes a seed layer, the vibration unit 130 (e.g., the first elastic layer 131, the second elastic layer 132) can be located at the surface of the seed layer away from the piezoelectric layer 122. In other embodiments, the material of the seed layer can also be different from that of the piezoelectric layer 122.

[0129] It should be noted that the shape of the stacked structure is not limited to Figure 1 the rectangle shown in the figure, but can also be a regular or irregular shape such as a triangle, a trapezoid, a circle, a semicircle, a quarter circle, an ellipse, a semielipse, etc., which will not be further limited herein. In addition, the number of stacked structures is not limited to Figure 1 one shown in the figure, but can also be two, three, four or more. Different stacked structures can be arranged side by side in the hollow portion of the base structure, or can be arranged in sequence along the arrangement direction of the layers of the stacked structure in the hollow portion of the base structure.

[0130] Figure 3 is a structural schematic diagram of another bone conduction sound transducing device according to some embodiments of the present application. Figure 3 The bone conduction sound transducing device 300 is substantially the same as the bone conduction sound transducing device 100 Figure 1 shown in the figure, the main difference between the bone conduction sound transducing device 300 and the bone conduction sound transducing device 100 is Figure 3 the shape of the stacked structure of the bone conduction sound transducing device 300. As Figure 3 shown, the bone conduction sound transducing device 300 includes a base structure 310 and a stacked structure, and the shape of the stacked structure is a trapezoid. Further, the width of the stacked structure in the bone conduction sound transducing device 300 tapers from the free end to the fixed end. In other embodiments, the width of the stacked structure in the bone conduction sound transducing device 300 can increase from the free end to the fixed end. It should be noted that the structure of the base structure 310 is similar to that of the base structure 110, and the structure of the vibration unit 330 is similar to that of the vibration unit 130. The details of each layer of the first electrode 321, the piezoelectric layer 322 and the second electrode 323 of the acoustic transducing unit 320 and the first elastic layer 331 and the second elastic layer 332 of the vibration unit 330 can be referred to Figure 1The contents of each layer of the acoustic transducing unit 120 and the vibration unit 130. In addition, other components (e.g., seed layers) in the acoustic transducing unit 120 and the vibration unit 130 are also applicable to Figure 3 The bone conduction sound transmission device 300 is not described here.

[0131] Figure 4 is a structural schematic diagram of a bone conduction sound transmission device according to another embodiment of the present application. As shown in Figure 4 The bone conduction sound transmission device 400 can include a base structure 410 and a laminated structure, and at least part of the laminated structure is connected to the base structure 410. In some embodiments, the base structure 410 can be a hollow frame structure, and part of the laminated structure (e.g., the end of the laminated structure away from the connection between the laminated structure and the base structure 410) can be located in the hollow part of the frame structure. It should be noted that the frame structure is not limited to Figure 4 the cuboid shown in the middle. In some embodiments, the frame structure can be a regular or irregular structure such as a prism or a cylinder. In some embodiments, the laminated structure can be fixedly connected to the base structure 410 in the form of a cantilever beam. Further, the laminated structure can include a fixed end and a free end, wherein the fixed end of the laminated structure is fixedly connected to the frame structure, and the free end of the laminated structure is not connected or in contact with the frame structure, so that the free end of the laminated structure can be suspended in the hollow part of the frame structure. In some embodiments, the fixed end of the laminated structure can be connected to the upper surface, the lower surface of the base structure 410, or the side wall where the hollow part of the base structure 410 is located. In some embodiments, the side wall where the hollow part of the base structure 410 is located can also be provided with a mounting groove matched with the fixed end of the laminated structure, so that the fixed end of the laminated structure is connected to the base structure 410. Here, "connection" can be understood as fixing the laminated structure and the base structure 410 by welding, riveting, clamping, bolting, etc. after the laminated structure and the base structure 410 are respectively prepared. In some embodiments, the laminated structure can also be deposited on the base structure 410 by physical deposition (e.g., physical vapor deposition) or chemical deposition (e.g., chemical vapor deposition) during the preparation process. In some embodiments, one or more laminated structures can be provided on the base structure 410, for example, the number of laminated structures can be 1, 2, 3, 7, etc. Further, the plurality of laminated structures can be arranged equidistantly and uniformly along the circumference of the base structure 410, or can be arranged non-uniformly.

[0132] In some embodiments, the stacked structure can include an acoustic transducing unit 420 and a vibrating unit 430. The vibrating unit 430 can be located on the upper surface or the lower surface of the acoustic transducing unit 420. In some embodiments, the vibrating unit 430 can include at least one elastic layer. The elastic layer can be a plate-like structure made of a semiconductor material. In some embodiments, the semiconductor material can include silicon dioxide, silicon nitride, gallium nitride, zinc oxide, silicon carbide, etc. In some embodiments, the acoustic transducing unit 420 can include an electrode layer and a piezoelectric layer 423, where the electrode layer includes a first electrode 421 and a second electrode 422. In the embodiments of the present specification, the piezoelectric layer 423 can generate a voltage (potential difference) under the deformation stress of the vibrating unit 430 based on the piezoelectric effect, and the first electrode 421 and the second electrode 422 can lead out the voltage (electric signal). In some embodiments, the first electrode 421 and the second electrode 422 are arranged on the same surface (e.g., the upper surface or the lower surface) of the piezoelectric layer 423, and the electrode layer and the vibrating unit 430 are located on different surfaces of the piezoelectric layer 423. For example, when the vibrating unit 430 is located on the lower surface of the piezoelectric layer 423, the electrode layer (the first electrode 421 and the second electrode 422) can be located on the upper surface of the piezoelectric layer 423. For another example, when the vibrating unit 430 is located on the upper surface of the piezoelectric layer 423, the electrode layer (the first electrode 421 and the second electrode 422) can be located on the lower surface of the piezoelectric layer 423. In some embodiments, the electrode layer and the vibrating unit 430 can also be located on the same side of the piezoelectric layer 423. For example, the electrode layer is located between the piezoelectric layer 423 and the vibrating unit 430. In some embodiments, the first electrode 421 can be bent into a first comb-shaped structure 4210, which can include a plurality of comb structures, and the first comb-shaped structure 4210 has a first spacing between adjacent comb structures, which can be the same or different. The second electrode 422 can be bent into a second comb-shaped structure 4220, which can include a plurality of comb structures, and the second comb-shaped structure 4220 has a second spacing between adjacent comb structures, which can be the same or different. The first comb-shaped structure 4210 and the second comb-shaped structure 4220 cooperate to form the electrode layer, and further, the comb structures of the first comb-shaped structure 4210 can extend into the second spacing of the second comb-shaped structure 4220, and the comb structures of the second comb-shaped structure 4220 can extend into the first spacing of the first comb-shaped structure 4210, thereby cooperating to form the electrode layer. The first comb-shaped structure 4210 and the second comb-shaped structure 4220 cooperate with each other, so that the first electrode 421 and the second electrode 422 are arranged compactly but do not intersect. In some embodiments, the first comb-shaped structure 4210 and the second comb-shaped structure 4220 extend along the length direction of the cantilever arm (e.g., from the fixed end to the free end).In some embodiments, the piezoelectric layer 423 is preferably a piezoelectric ceramic material, and when the piezoelectric layer 423 is a piezoelectric ceramic material, the polarization direction of the piezoelectric layer 423 is consistent with the length direction of the cantilever beam, and the piezoelectric constant d of the piezoelectric ceramic is utilized. 33 The piezoelectric constant d refers to the proportional constant of the piezoelectric layer converting mechanical energy into electrical energy. It should be noted that, 33 The piezoelectric constant d refers to the proportional constant of the piezoelectric layer converting mechanical energy into electrical energy. It should be noted that, Figure 4 The piezoelectric layer 423 shown in FIG. 4 can also be other materials, and when the polarization direction of the piezoelectric layer 423 of other materials is consistent with the thickness direction of the cantilever beam, the acoustic transducing unit 420 can be replaced by Figure 1 The acoustic transducing unit 120 shown in FIG. 1.

[0133] When the relative movement between the stack structure and the base structure 410 occurs, the deformation degree of the vibration unit 430 at different positions in the stack structure is different, that is, the deformation stress of the piezoelectric layer 423 of the acoustic transducing unit 420 at different positions of the vibration unit 430 is different. In order to improve the sensitivity of the bone conduction sound transmission device, in some embodiments, the acoustic transducing unit 420 can be arranged only at the position where the deformation degree of the vibration unit 430 is large, so as to improve the signal-to-noise ratio of the bone conduction sound transmission device 400. Correspondingly, the area of the electrode layer and / or the piezoelectric layer 423 of the acoustic transducing unit 420 can be not greater than the area of the vibration unit 430. In some embodiments, in order to further improve the signal-to-noise ratio of the bone conduction sound transmission device 400, the area of the acoustic transducing unit 420 covering the vibration unit 430 is less than the area of the vibration unit 430. Preferably, the area of the acoustic transducing unit 420 covering the vibration unit 430 is not greater than 1 / 2 of the area of the vibration unit 430. Preferably, the area of the acoustic transducing unit 420 covering the vibration unit 430 is not greater than 1 / 3 of the area of the vibration unit 430. Further preferably, the area of the acoustic transducing unit 420 covering the vibration unit 430 is not greater than 1 / 4 of the area of the vibration unit 430. Further, in some embodiments, the acoustic transducing unit 420 can be close to the connection between the stack structure and the base structure 410. Since the deformation degree of the vibration unit 430 (for example, the elastic layer) is large when the vibration unit 430 is subjected to external force near the connection between the stack structure and the base structure 410, the deformation stress of the acoustic transducing unit 420 is also large. Therefore, arranging the acoustic transducing unit 420 in the area with large deformation stress can improve the signal-to-noise ratio of the bone conduction sound transmission device 400 on the basis of improving the sensitivity of the bone conduction sound transmission device 400. It should be noted that here the acoustic transducing unit 420 can be close to the connection between the stack structure and the base structure 410 is relative to the free end of the stack structure, that is, the distance from the acoustic transducing unit 420 to the connection between the stack structure and the base structure 410 is less than the distance from the acoustic transducing unit 420 to the free end. In some embodiments, the sensitivity and signal-to-noise ratio of the bone conduction sound transmission device 100 can be improved only by adjusting the area and position of the piezoelectric layer 423 in the acoustic transducing unit 420. For example, the electrode layer covers the surface of the vibration unit 430 entirely or partially, and the area of the piezoelectric layer 423 can be not greater than the area of the electrode layer. Preferably, the covering area of the piezoelectric layer 423 on the vibration unit 430 is not greater than 1 / 2 of the area of the electrode layer. Preferably, the covering area of the piezoelectric layer 423 on the vibration unit 430 is not greater than 1 / 3 of the area of the piezoelectric layer. Further preferably, the covering area of the piezoelectric layer 423 on the vibration unit 430 is not greater than 1 / 4 of the area of the electrode layer.In some embodiments, the area of the piezoelectric layer 423 can be the same as the area of the vibration unit 430, the entire area of the electrode layer can be located at the piezoelectric layer 423, and the edges of the electrode layer can be spaced apart from the edges of the piezoelectric layer 423, so that the first electrode 421 and the second electrode 422 in the electrode layer avoid the area with poor material quality at the edges of the piezoelectric layer 423, thereby further improving the signal-to-noise ratio of the bone conduction sound transmission device 400.

[0134] In some embodiments, in order to increase the output electric signal and improve the signal-to-noise ratio of the bone conduction sound transmission device, the shape, thickness, material, size (e.g., length, width, thickness) of the acoustic transduction unit 420 (e.g., the first electrode 421, the piezoelectric layer 423, the second electrode 422) and the vibration unit 430 (e.g., the elastic layer) can be adjusted to improve the signal-to-noise ratio and sensitivity of the bone conduction sound transmission device 400.

[0135] In some embodiments, in order to increase the output electric signal and improve the signal-to-noise ratio of the bone conduction sound transmission device, the length, width, spacing (e.g., first spacing and second spacing) between the individual comb structures of the first comb structure 4210 and the second comb structure 4220, and the length of the entire acoustic transduction unit 420 can be adjusted to increase the output voltage electric signal and improve the signal-to-noise ratio of the bone conduction sound transmission device.

[0136] Figure 5 FIG. 1 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application; Figure 6 FIG. 2 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application; Figure 5 FIG. 3 is a cross-sectional view of a partial structure of the bone conduction sound transmission device shown in FIG. 2. As shown in FIG. 3, the bone conduction sound transmission device 200 can include a base structure 210 and a laminated structure, wherein at least part of the laminated structure is connected to the base structure 210. Figure 5 FIG. 4 is a cross-sectional view of a partial structure of the bone conduction sound transmission device shown in FIG. 2. As shown in FIG. 4, the bone conduction sound transmission device 200 can include a base structure 210 and a laminated structure, wherein at least part of the laminated structure is connected to the base structure 210. Figure 6 In some embodiments, the base structure 210 can be a frame structure with an internal hollow, and part of the laminated structure can be located in the hollow part of the frame structure. It should be noted that the frame structure is not limited to the cuboid shape shown in FIG. 2, and in some embodiments, the frame structure can be a regular or irregular structure such as a prism, a cylinder, etc. Figure 5 In some embodiments, the base structure 210 can be a frame structure with an internal hollow, and part of the laminated structure can be located in the hollow part of the frame structure. It should be noted that the frame structure is not limited to the cuboid shape shown in FIG. 2, and in some embodiments, the frame structure can be a regular or irregular structure such as a prism, a cylinder, etc.

[0137] In some embodiments, the laminated structure can include an acoustic transduction unit 220 and a vibration unit.

[0138] In some embodiments, the resonant frequency of the bone conduction sound transmission device (or bone conduction microphone) is positively correlated with the stiffness of the vibration unit. When other parameters (e.g., the mass of the laminated structure, etc.) are constant, the greater the stiffness of the vibration unit, the higher the resonant frequency of the bone conduction sound transmission device; the smaller the stiffness of the vibration unit, the lower the resonant frequency of the bone conduction sound transmission device.

[0139] In some embodiments, the resonant frequency of the bone conduction sound transmission device is negatively correlated with the mass of the laminated structure. With other parameters (e.g., the stiffness of the vibrating element) remaining constant, a greater mass of the laminated structure results in a lower resonant frequency of the bone conduction sound transmission device; conversely, a smaller mass results in a higher resonant frequency.

[0140] In some embodiments, the vibration unit may be disposed on the upper or lower surface of the acoustic transducer unit 520. For example... Figure 5 As shown, the vibration unit includes a suspended membrane structure 530, which is fixed to the substrate structure 510 by connecting to the substrate structure 510 via its peripheral side. The central region of the suspended membrane structure 530 is suspended in the hollow portion of the substrate structure 510. In some embodiments, the suspended membrane structure 530 may be located on the upper or lower surface of the substrate structure 510. In some embodiments, the peripheral side of the suspended membrane structure 530 may also be connected to the inner wall of the hollow portion of the substrate structure 510. Here, "connection" can be understood as fixing the suspended membrane structure 530 to the upper or lower surface of the substrate structure 510 or the sidewall of the hollow portion of the substrate structure 510 by mechanical fixing methods (e.g., strong bonding, riveting, clipping, embedding, etc.) after the suspended membrane structure 530 and the substrate structure 510 are respectively prepared, or depositing the suspended membrane structure 530 onto the substrate structure 510 by physical deposition (e.g., physical vapor deposition) or chemical deposition (e.g., chemical vapor deposition) during the preparation process.

[0141] In some embodiments, the stiffness of the vibration unit can be the stiffness of the suspension membrane structure 530.

[0142] In some embodiments, the suspended membrane structure 530 may include at least one elastic layer. The elastic layer may be a film structure made of a semiconductor material. In some embodiments, the semiconductor material may include silicon dioxide, silicon nitride, gallium nitride, zinc oxide, silicon carbide, monocrystalline silicon, polycrystalline silicon, etc. In some embodiments, the suspended membrane structure 530 may be made of one of the above-mentioned semiconductor materials, or may be made of two or more of the above-mentioned semiconductor materials stacked and composited along the thickness direction. For example, the suspended membrane structure 530 may be a composite layer of monocrystalline silicon (or polycrystalline silicon) and silicon dioxide, a composite layer of monocrystalline silicon (or polycrystalline silicon) and silicon nitride, or a composite layer of silicon nitride and monocrystalline silicon (or polycrystalline silicon) and silicon dioxide.

[0143] In some embodiments, the shape of the suspension structure 530 can be circular, elliptical, or polygonal, such as triangular, quadrilateral, pentagonal, or hexagonal, or any other arbitrary shape. For example, Figure 22 As shown, the suspension structure 530 can be quadrilateral. In some embodiments, such as Figure 23As shown, the membrane suspension structure 530 is circular. In some embodiments, the membrane suspension structure 530 can be circular, and the radius of the membrane suspension structure 530 is 500 um-1500 um. In some embodiments, the radius of the membrane suspension structure 530 is 520 um-1400 um. In some embodiments, the radius of the membrane suspension structure 530 is 550 um-1300 um. In some embodiments, the radius of the membrane suspension structure 530 is 570 um-1200 um. In some embodiments, the radius of the membrane suspension structure 530 is 600 um-1100 um. In some embodiments, the radius of the membrane suspension structure 530 is 630 um-1000 um. In some embodiments, the radius of the membrane suspension structure 530 is 650 um-900 um. In some embodiments, the radius of the membrane suspension structure 530 is 670 um-850 um. It should be noted that the shape and size (e.g., radius) of the membrane suspension structure 530 in this application are the shape and size of the cross section perpendicular to the thickness direction (indicated by the arrow in the middle). Figure 6

[0144] In some embodiments, the acoustic transduction unit 520 can be located on the upper surface or the lower surface of the membrane suspension structure 530.

[0145] In some embodiments, the membrane suspension structure 530 can include a hole 5300, which is arranged on the outside or the inside of the acoustic transduction unit 520. In some embodiments, the membrane suspension structure 530 can include a plurality of holes 5300, which are distributed around the center of the acoustic transduction unit 520 along the circumferential direction (e.g., the outer circumferential direction and / or the inner circumferential direction) of the acoustic transduction unit 520. It can be understood that by arranging a plurality of holes 5300 on the membrane suspension structure 530, the stiffness of the membrane suspension structure 530 at different positions can be adjusted, so that the stiffness of the membrane suspension structure 530 at the region near the plurality of holes 5300 is reduced, and the stiffness of the membrane suspension structure 530 at the region far from the plurality of holes 5300 is relatively large. When the membrane suspension structure 530 moves relative to the base structure 510, the deformation degree of the membrane suspension structure 530 at the region near the plurality of holes 5300 is larger, and the deformation degree of the membrane suspension structure 530 at the region far from the plurality of holes 5300 is smaller. At this time, placing the acoustic transduction unit 520 at the region near the plurality of holes 5300 on the membrane suspension structure 530 can be more conducive to the acoustic transduction unit 520 to collect vibration signals, thereby effectively improving the sensitivity of the bone conduction sound transmission device 500, and at the same time, the structure of each component in the bone conduction sound transmission device 500 is relatively simple, which is convenient for production or assembly.

[0146] In some embodiments, the hole 5300 on the membrane suspension structure 530 can be a circular hole, an elliptical hole, a square hole, or any other polygonal hole. For example, as shown in FIGS. 5A and 5B, the hole 5300 is a square hole. For example, as shown in FIGS. 5C and 5D, the hole 5300 is a circular hole. Figure 22 Figure 23 Figure 24 ​​​As shown, the holes 5300 are irregularly shaped holes. Preferably, as shown in Figure 25 and Figure 26 As shown, the holes 5300 are circular holes, which can reduce local stress concentration and improve the sensitivity of the bone conduction sound transmission device. In some embodiments, the holes 5300 are circular, and the radius of the holes 5300 can be 20um-300um. In some embodiments, the radius of the holes 5300 is 25um-250um. In some embodiments, the holes 5300 can be non-through holes (e.g., grooves on a suspended membrane). In some embodiments, the holes 5300 can be through holes. In some embodiments, the number of holes 5300 can be one or more. For example, the number of holes 5300 can include 2, 4, 6, 8, 10, 12, 14, 16, 18.

[0147] In some embodiments, as shown in Figures 22-24 the holes 5300 can be distributed on the outer periphery of the acoustic transduction unit 520. In some embodiments, as shown in Figure 25 the holes 5300 can also be distributed on the inner periphery of the acoustic transduction unit 520. In some embodiments, the holes 5300 can be uniformly or non-uniformly distributed on the outer periphery and / or inner periphery of the acoustic transduction unit 520. Preferably, as shown in Figures 23-25 the holes 5300 are uniformly distributed at equal intervals on the outer periphery and / or inner periphery of the acoustic transduction unit 520. In some embodiments, the holes 5300 can form one, two or more circles. For example, as shown in Figures 23-25 the holes 5300 form one circle. For another example, as shown in Figure 26 the holes 5300 form two circles. Preferably, the holes 5300 form one circle. In some embodiments, the shape formed by the holes 5300 can be circular, elliptical, square, polygonal, other regular or irregular shape. It should be noted that the shape formed by the holes 5300 in this application is the shape formed by the centers (or centers) of the holes 5300, and the size of the shape formed by the centers of the holes 5300 is the distance value between the two points farthest apart in the shape formed by the centers of the holes 5300. For example, the shape formed by the centers of the holes 5300 is circular, and the size of the shape formed by the centers of the holes 5300 can be the diameter of the circle. For another example, the shape formed by the centers of the holes 5300 is square, and the size of the shape formed by the centers of the holes 5300 can be the diagonal length of the square. For another example, the shape formed by the centers of the holes 5300 is irregular, and the size of the shape formed by the centers of the holes 5300 can be the distance between the two top corners farthest apart in the irregular shape.

[0148] In some embodiments, the shape of the acoustic transduction unit 520 can include square, circular, elliptical, curved ring, polygonal, other regular or irregular shape. For example, as shown in Figure 22As shown, the acoustic transducer unit 520 is square in shape. For example, as... Figures 23-27 As shown, the acoustic transducer unit 520 is annular in shape. In some embodiments, the acoustic transducer unit 520 may be annular with one or more openings. For example, as... Figure 27 As shown, the acoustic transducer unit 520 is an annular shape with two openings. In some embodiments, the acoustic transducer unit 520 is a circular closed ring.

[0149] It should be noted that, in one or more embodiments of this application, the shape of the acoustic transducer unit 520 may refer to the direction perpendicular to the thickness of the acoustic transducer unit. Figure 6 The shape of the cross-section (in the direction indicated by the middle arrow).

[0150] In some embodiments, the relevant dimensions of the acoustic transducer 520 (e.g., the inner or outer diameter of the acoustic transducer) affect the resonant frequency of the vibration system. In some embodiments, the dimensions of the acoustic transducer may include the outer and / or inner diameter of a cross-section of the acoustic transducer perpendicular to the thickness direction. In some embodiments, the outer diameter of the acoustic transducer 520 may refer to the outer diameter of the cross-section of the acoustic transducer 520 perpendicular to the thickness direction. In some embodiments, the inner diameter of the acoustic transducer 520 may refer to the inner diameter of the cross-section of the acoustic transducer 520 perpendicular to the thickness direction. The outer diameter of the cross-section may refer to the distance between the two farthest points on the outer edge of the cross-section. For example, if the cross-section is circular, the outer diameter may refer to the diameter of the circle. As another example, if the cross-section is elliptical, the outer diameter may refer to the major diameter of the ellipse. Yet another example, if the cross-section is rectangular, the outer diameter may refer to the length of the diagonal of the rectangle. For example, if the cross-section is an irregular quadrilateral, the outer diameter of the cross-section can refer to the distance between the two farthest vertices of the quadrilateral. The inner diameter of the cross-section can refer to the distance between the two closest points on the inner edge of the cross-section, with the straight line passing through these two points passing through the geometric center of the inner edge. For example, if the inner edge of the cross-section is circular, the inner diameter of the cross-section can refer to the diameter of the circle. As another example, if the inner edge of the cross-section is elliptical, the inner diameter of the cross-section can refer to the minor diameter of the ellipse. And as yet another example, if the inner edge of the cross-section is rectangular, the inner diameter of the cross-section can refer to the length of the shorter side of the rectangle.

[0151] In some embodiments, the acoustic transducing unit 520 can include at least an effective acoustic transducing unit. The effective acoustic transducing unit refers to a partial structure of the acoustic transducing unit that contributes to the final electrical signal. In some embodiments, the inner diameter of the effective acoustic transducing unit 520 can be 100-700 um. In some embodiments, the inner diameter of the effective acoustic transducing unit 520 can be 130-600 um. In some embodiments, the inner diameter of the effective acoustic transducing unit 520 can be 150-500 um. In some embodiments, the inner diameter of the effective acoustic transducing unit 520 can be 200-400 um. In some embodiments, the outer diameter of the effective acoustic transducing unit 520 can be 110-710 um. In some embodiments, the outer diameter of the effective acoustic transducing unit 520 can be 150-650 um. In some embodiments, the outer diameter of the effective acoustic transducing unit 520 can be 200-620 um. In some embodiments, the outer diameter of the effective acoustic transducing unit 520 can be 250-600 um.

[0152] In some embodiments, the shape enclosed by the plurality of holes 5300 is consistent with the shape of the acoustic transducing unit 520. For example, as shown in FIG. 5A, the shape of the acoustic transducing unit 520 is square, and the shape enclosed by the plurality of holes 5300 is square. For another example, as shown in FIG. 5B, the shape enclosed by the plurality of holes 5300 is circular, and the shape of the acoustic transducing unit 520 is circular. Figure 22 Figure 23 In some embodiments, the shape of the plurality of holes 5300 is consistent with the shape of the acoustic transducing unit 520. For example, as shown in FIG. 5C, the shape of the plurality of holes 5300 is square, and the shape of the acoustic transducing unit 520 is square. Preferably, the plurality of holes 5300 are distributed in a circular manner along the outer periphery of the acoustic transducing unit 520. In some embodiments, the shape of the plurality of holes 5300 can be consistent or inconsistent. For example, the shape of the plurality of holes 5300 can be one of circular, elliptical, square, polygonal, irregular shape. For example, the shape of the plurality of holes 5300 can include a combination of two or more of circular, elliptical, square, polygonal, irregular shape. In some embodiments, the radius of the circle enclosed by the plurality of holes 5300 can be 300-700 um. In some embodiments, the radius of the circle enclosed by the plurality of holes 5300 can be 350-650 um. Figure 22

[0153] ​​In some embodiments, the outer diameter dimension of the effective acoustic transducing unit 520 can be less than, equal to, or greater than the dimension of the shape circumscribed by the center of each of the plurality of holes 5300. In some embodiments, the inner diameter dimension of the effective acoustic transducing unit 520 can be less than, equal to, or greater than the dimension of the shape circumscribed by the center of each of the plurality of holes 5300. Preferably, the shape of the acoustic transducing unit 520 is a circular ring (i.e., the inner and outer sides of the cross-section of the acoustic transducing unit 520 perpendicular to the thickness direction are both circular), the shape circumscribed by the plurality of holes 5300 is circular, and the radius of the inner edge of the effective acoustic transducing unit 520 (i.e., the radius of the inner side of the cross-section of the effective acoustic transducing unit 520 perpendicular to the thickness direction) is less than the radius of the circle circumscribed by the plurality of holes 5300. In some embodiments, the radius of the inner edge of the effective acoustic transducing unit 520 is less than the radius of the circle circumscribed by the plurality of holes 5300, and the difference between the radius of the inner edge of the effective acoustic transducing unit 520 and the radius of the circle circumscribed by the plurality of holes 5300 can be 50-300 um. In some embodiments, the difference between the radius of the inner edge of the effective acoustic transducing unit 520 and the radius of the circle circumscribed by the plurality of holes 5300 can be 70-250 um. In some embodiments, the difference between the radius of the inner edge of the effective acoustic transducing unit 520 and the radius of the circle circumscribed by the plurality of holes 5300 can be 90-230 um.

[0154] In some embodiments, the outer diameter size of the effective acoustic transduction unit 520 can be less than, equal to, or greater than the size of the hollow cavity of the base structure 510. In some embodiments, the inner diameter size of the effective acoustic transduction unit 520 can be less than, equal to, or greater than the size of the hollow cavity of the base structure 510. The size of the hollow cavity of the base structure 510 is the distance value between the two farthest points on the inner side edge of the cross section of the base structure 510 perpendicular to the thickness direction. The shape and size of the inner side edge of the cross section of the base structure 510 perpendicular to the thickness direction are similar to the shape and size of the circle formed by the centers of the plurality of holes 5300, which will not be repeated here. Preferably, the outer diameter size of the effective acoustic transduction unit 520 is less than the size of the hollow cavity of the base structure 510. In some embodiments, the outer diameter size of the effective acoustic transduction unit 520 is less than the size of the hollow cavity of the base structure 510, and the difference between the size of the hollow cavity of the base structure 510 and the outer diameter size of the effective acoustic transduction unit 520 is in the range of 5um-400um. In some embodiments, the shape of the acoustic transduction unit 520 and the hollow cavity of the base structure 510 can be the same or different. In some embodiments, when the shape of the acoustic transduction unit 520 and the hollow cavity of the base structure 510 are the same, the difference between the size of the hollow cavity of the base structure 510 and the outer diameter size of the effective acoustic transduction unit 520 can be in the range of 5um-400um. For example, the shape of the acoustic transduction unit 520 is a circular ring, the shape of the hollow cavity of the base structure 510 is a circle, and the difference between the outer diameter size of the effective acoustic transduction unit 520 and the size of the hollow cavity of the base structure 510 can be in the range of 5um-400um. In some embodiments, the difference between the maximum size of the two can be in the range of 20um-380um. In some embodiments, the difference between the maximum size of the two can be in the range of 50um-350um. In some embodiments, the difference between the maximum size of the two can be in the range of 80um-320um.

[0155] In some embodiments, the resonant frequency (such that the resonant frequency is in the range of 2kHz-5kHz) and stress distribution of the bone conduction sound transmission device 500 can also be adjusted by changing the size, number, spacing distance, and position of the plurality of holes 5300 to improve the sensitivity of the bone conduction sound transmission device 500. It should be noted that the resonant frequency is not limited to the above-mentioned 2kHz-5kHz, but can also be 3kHz-4.5kHz, or 4kHz-4.5kHz, and the range of the resonant frequency can be adaptively adjusted according to different application scenarios, which will not be further limited here.

[0156] In combination Figure 5 and Figure 6In some embodiments, the acoustic transducing unit 520 can include a first electrode layer 521, a piezoelectric layer 522, and a second electrode layer 523 arranged in order from top to bottom, where the positions of the first electrode layer 521 and the second electrode layer 523 can be interchanged. The piezoelectric layer 522 can generate a voltage (potential difference) based on the piezoelectric effect under the deformation stress of the vibration unit (e.g., the suspension membrane structure 530), and the first electrode layer 521 and the second electrode layer 523 can guide the voltage (electric signal) out. In some embodiments, the material of the piezoelectric layer can include a piezoelectric thin film material, which can be a thin film material (e.g., AIN thin film material) made by a deposition process (e.g., a magnetron sputtering deposition process). In other embodiments, the material of the piezoelectric layer can include a piezoelectric crystal material and a piezoelectric ceramic material. The piezoelectric crystal refers to a piezoelectric single crystal. In some embodiments, the piezoelectric crystal material can include quartz, zinc blende, boracite, tourmaline, red zinc ore, GaAs, barium titanate and its derivative structure crystal, KH2PO4, NaKC4H4O6·4H2O (Rochelle salt), sugar, etc., or any combination thereof. The piezoelectric ceramic material refers to a piezoelectric polycrystal formed by the random collection of microcrystalline grains obtained by solid-phase reaction and sintering between different material powders. In some embodiments, the piezoelectric ceramic material can include barium titanate (BT), lead zirconate titanate (PZT), lead barium lithium niobate (PBLN), modified lead titanate aluminum nitride (AIN), zinc oxide (ZnO), etc., or any combination thereof. In some embodiments, the piezoelectric layer 522 can also be a piezoelectric polymer material, for example, polyvinylidene fluoride (PVDF). In some embodiments, the first electrode layer 521 and the second electrode layer 523 are made of a conductive material structure. Exemplary conductive materials can include metals, alloy materials, metal oxide materials, graphene, etc., or any combination thereof. In some embodiments, the metals and alloy materials can include nickel, iron, lead, platinum, titanium, copper, molybdenum, zinc, etc., or any combination thereof. In some embodiments, the alloy materials can include copper-zinc alloy, copper-tin alloy, copper-nickel-silicon alloy, copper-chromium alloy, copper-silver alloy, etc., or any combination thereof. In some embodiments, the metal oxide materials can include RuO2, MnO2, PbO2, NiO, etc., or any combination thereof.

[0157] In some embodiments, an effective acoustic transducing unit can include overlapping regions of the first electrode layer 521, the piezoelectric layer 522, and the second electrode layer 523. For example, the first electrode layer 521, the piezoelectric layer 522, and the second electrode layer 523 have the same shape and area, and partially cover the suspended membrane structure 530, then the first electrode layer 521, the piezoelectric layer 522, and the second electrode layer 523 are effective transducing units. For another example, the first electrode layer 521 and the piezoelectric layer 522 partially cover the suspended membrane structure 530, and the second electrode layer 523 fully covers the suspended membrane structure 530, then the first electrode layer 521, the piezoelectric layer 522, and the second electrode layer 523 form effective acoustic transducing units in the corresponding parts along the thickness direction respectively. It should be noted that the size (e.g., inner diameter, outer diameter) and the corresponding parameters (e.g., the difference between the radius of the edge of the acoustic transducing unit 520 and the radius of the circle surrounded by the plurality of holes 5300, the difference range between the size of the hollow cavity of the base structure 510 and the outer diameter of the acoustic transducing unit 520, the radial distance from the edge of the acoustic transducing unit 520 to the center of each hole 5300) of the acoustic transducing unit described in this specification are the size and the corresponding parameters of the effective acoustic transducing unit.

[0158] In some embodiments, the acoustic transducer unit 520 may further include a seed layer. The seed layer can optimize the lattice structure of the first electrode layer 521, the second electrode layer 523, and the piezoelectric layer 522 deposited thereon, ensuring the quality of the acoustic transducer unit 520 and increasing film adhesion. In some embodiments, a seed layer can be prepared on a silicon substrate using physical vapor deposition (PVD) or chemical vapor deposition (CVD). In some embodiments, the thickness of the seed layer is 5 nm-200 nm. In some embodiments, the thickness of the seed layer can be 8 nm-150 nm. It should be noted that the acoustic transducer unit 520 may also be without a seed layer. In some embodiments, the second electrode layer 523 can be prepared on the upper surface of the seed layer or on the upper surface of the silicon substrate using PVD or CVD. In some embodiments, the thickness of the second electrode layer 523 can be 80 nm-250 nm. In some embodiments, the thickness of the second electrode layer 523 is 100 nm-200 nm. In some embodiments, a piezoelectric layer 522 can be prepared on the upper surface of the second electrode layer 523 using a PVD or CVD method. In some embodiments, the thickness of the piezoelectric layer 522 can be 0.8 μm-5 μm. In some embodiments, the thickness of the piezoelectric layer 522 is 0.8 μm-4 μm. In some embodiments, a first electrode layer 521 can be prepared on the upper surface of the piezoelectric layer 522 using a PVD or CVD method. In some embodiments, the thickness of the first electrode layer 521 can be 80 nm-250 nm. In some embodiments, the thickness of the first electrode layer 521 is 90 nm-230 nm. In some embodiments, etching can be performed sequentially on the first electrode layer 521, the piezoelectric layer 522, and the second electrode layer 523. In some embodiments, the etching of the first electrode layer 521, the piezoelectric layer 522, and the second electrode layer 523 can be performed using dry etching or wet etching.

[0159] like Figure 5 As shown, in some embodiments, multiple holes 5300 form a circular region. To improve the sound pressure output effect of the acoustic transducer 520, the acoustic transducer 520 can be disposed on the diaphragm structure 530 near the region of multiple holes 5300. Further, the acoustic transducer 520 can be a ring structure, distributed along the inner side of the circular region formed by the multiple holes 5300. Figures 23-24 As shown, the acoustic transducer units 520 are distributed along the inner side of the circular region enclosed by the plurality of holes 5300. In some embodiments, the acoustic transducer units 520, which have a ring-shaped structure, may also be distributed along the outer side of the circular region enclosed by the plurality of holes 5300. Figure 25As shown, the acoustic transducer units 520 are distributed along the outer side of the circular region enclosed by the plurality of holes 5300. Preferably, the annular acoustic transducer units 520 can be distributed along the inner side of the circular region enclosed by the plurality of holes 5300, and the circular region enclosed by the plurality of holes 5300 is distributed inside the substrate structure 510. In some embodiments, the piezoelectric layer 522 of the acoustic transducer unit 520 can be a piezoelectric ring, and the first electrode layer 521 and the second electrode layer 523 located on the upper and lower surfaces of the piezoelectric ring can be electrode rings.

[0160] In some embodiments, by adjusting the size, number, and distribution of a plurality of holes 5300 in the suspension structure 530, as well as the shape, size, and position of the acoustic transducer unit 520, the equivalent stiffness and equivalent mass of the bone conduction sound transmission device 500 can be adjusted, thereby affecting the resonant frequency and stress distribution of the bone conduction sound transmission device 500, and consequently adjusting the output electrical signal of the bone conduction sound transmission device 500 to improve its sensitivity. In some embodiments, the holes 5300 on the suspension structure 530 can be fabricated by an etching process. In some embodiments, the etching process can include a dry etching process or a wet etching process.

[0161] In some embodiments, the acoustic transducer unit 520 is further provided with a lead structure 5200, which is used to transmit the electrical signals collected by the electrode rings (e.g., the first electrode layer 521 and the second electrode layer 523) to subsequent circuits. In some embodiments, the first electrode layer 521 and the second electrode layer 523 are connected to the substrate structure 510 through the lead structure 5200. In some embodiments, the lead structure 5200 includes a first lead and a second lead. One end of the first lead is connected to the first electrode layer 521, and the other end of the first lead is connected to the substrate structure 510; one end of the second lead is connected to the second electrode layer 523, and the other end of the second lead is connected to the substrate structure 510.

[0162] In some embodiments, the sensitivity of the bone conduction sound transmission device 500 can be improved by adjusting the shape, size (e.g., length, width, thickness), and material of the lead structure 5200 to reduce the resonant frequency.

[0163] In some embodiments, the lead structure 5200 may include a straight line, a broken line, or a curve. Preferably, as shown below... Figures 22-27 As shown, the lead structure 5200 is a straight line. For example, as... Figure 28 As shown, the lead structure 5200 is curved. In some embodiments, the width of the lead structure 5200 (e.g., Figures 27-28The width d) shown can be 2um-100um. In some embodiments, the width is 10um-100um. In some embodiments, the width is 15um-90um. In some embodiments, the width is 20um-80um.

[0164] Figure 29 is a schematic diagram of a lead structure in another bone conduction sound transmission device according to some embodiments of the present application. In some embodiments, the first electrode layer 521 is connected to the upper surface, lower surface or side surface of the base structure 510 through the lead structure 5200. In some embodiments, as shown, the first electrode layer 521 is connected to the solder pad 5210 through the lead structure 5200. The solder pad 5210 can be located on the upper surface, lower surface or side surface of the base structure 510, as shown. Figure 29 Figure 29 ​As shown, the pad 5210 can be located on the upper surface of the base structure 510 for leading out the electrical signal between the acoustic transducing unit 520 and the housing, the lead structure 5200, etc. Connecting the first electrode layer 521 to the pad 5210 through the lead structure 5200 can reduce the electrical signal between the acoustic transducing unit 520 and the housing, the lead structure 5200, etc., thereby reducing the parasitic capacitance and improving the sensitivity of the bone conduction sound transducing device 500. In some embodiments, the pad 5210 can be circular, elliptical, triangular, polygonal, irregular, or the like. In some embodiments, the maximum dimension of the pad 5210 ranges from 80 um to 500 um. The maximum dimension can be the side length or the diameter. For example, the pad 5210 is rectangular, and the maximum side length of the pad 5210 can range from 80 um to 500 um. For another example, the pad 5210 is circular, and the maximum diameter of the pad 5210 can range from 80 um to 500 um. In some embodiments, the maximum dimension of the pad 5210 ranges from 85 um to 450 um. In some embodiments, the maximum dimension of the pad 5210 ranges from 90 um to 400 um. It should be noted that the shape and size of the pad 5210 in this application are the shape and size of the cross section perpendicular to the thickness direction. In some embodiments, the pad 5210 can be made by depositing one or more layers of metal (e.g., Pt, Au, Ti, Cr, Ti / Au, etc.) that is easy to wire. Preferably, the metal deposited on the pad 5210 can be Ti / Au or Gr / Au. In some embodiments, the pad 5210 can be prepared by a metal lift-off process (LIFT-OFF). In some embodiments, the deposition thickness of the pad 5210 ranges from 100 nm to 300 nm. Preferably, the deposition thickness ranges from 150 nm to 250 nm. In some embodiments, a uniform glue and photoresist development process can also be performed on the back of the silicon substrate to obtain a patterned deep silicon release window, and a deep silicon etching process is used to etch the silicon to the oxide layer of the silicon substrate, and then the oxide layer of the silicon substrate is removed to obtain the bone conduction sound transducing device 3100.

[0165] In some embodiments, to improve the output electrical signal of the bone conduction sound transmission device 500, the radial distance from the edge of the effective acoustic transducer unit 520 (e.g., annular structure) to the center of each hole 5300 can be 50µm-400µm. The edge of the effective acoustic transducer unit 520 (e.g., annular structure) can be either the inner edge or the outer edge. In some embodiments, the radial distance from the edge of the effective acoustic transducer unit 520 (e.g., annular structure) to the center of each hole 5300 can be 100µm-350µm. Preferably, the radial distance from the edge of the effective acoustic transducer unit 520 (e.g., annular structure) to the center of each hole 5300 can be 150µm-300µm. More preferably, the radial distance from the edge of the effective acoustic transducer unit 520 (e.g., annular structure) to the center of each hole 5300 can be 150µm-250µm.

[0166] In some embodiments, the thickness or density of different regions of the suspended membrane structure 530 is the same. In some embodiments, the thickness of the suspended membrane structure 530 is 0.5µm-10µm. Preferably, the thickness is 0.5µm-5µm. In some alternative embodiments, the deformation stress at different locations of the suspended membrane structure 530 can also be changed by adjusting the thickness or density of different regions of the suspended membrane structure 530. As an example only, in some embodiments, the acoustic transducer unit 520 is configured as a ring structure, and the thickness of the region on the suspended membrane structure 530 located inside the ring structure is greater than the thickness of the region located outside the ring structure. The thickness of the inner region or the thickness of the outer region of the ring structure is... Figure 6 The dimension in the thickness direction. In other embodiments, the density of the suspension membrane structure 530 in the inner region of the annular structure is greater than the density in the outer region of the annular structure. By changing the density or thickness of the suspension membrane structure 530 at different locations, the mass of the suspension membrane in the inner region of the annular structure is greater than the mass of the suspension membrane in the outer region of the annular structure, or the rigidity of the suspension membrane in the inner region of the annular structure is less than the rigidity of the suspension membrane in the outer region of the annular structure. When the suspension membrane structure 530 moves relative to the substrate structure 510, the degree of deformation of the suspension membrane structure 530 near the annular structure of the acoustic transducer unit 520 (i.e., the inner region of the suspension membrane structure 530) is greater, and the deformation stress generated is also greater. This results in a larger electrical signal output by the bone conduction sound transmission device 500, and thus a higher sensitivity of the bone conduction sound transmission device 500.

[0167] It should be noted that the shape of the area enclosed by the multiple holes 5300 is not limited to... Figure 5The circular shape can also be a semicircular shape, a 1 / 4 circular shape (a sector with a central angle of 90°), an elliptical shape, a semicircular shape, a triangular shape, a rectangular shape, and other regular or irregular shapes. The shape of the acoustic transduction unit 520 can be adaptively adjusted according to the shape of the area surrounded by the plurality of holes 5300. For example, when the shape of the area surrounded by the plurality of holes 5300 is a rectangular shape, the shape of the acoustic transduction unit 520 can be a rectangular shape, and the acoustic transduction unit 520 in the rectangular shape can be distributed along the inner side or the outer side of the rectangular shape surrounded by the plurality of holes 5300. For another example, when the shape of the area surrounded by the plurality of holes 5300 is a semicircular shape, the shape of the acoustic transduction unit 520 can be a semicircular shape, and the acoustic transduction unit 520 in the semicircular shape can be distributed along the inner side or the outer side of the rectangular shape surrounded by the plurality of holes 5300. In some embodiments, Figure 5 The suspension membrane structure 530 in

[0168] Figure 7 FIG. 6 is a structural schematic diagram of a bone conduction sound device according to some embodiments of the present application. Figure 30 FIG. 7 is a structural schematic diagram of a bone conduction sound device according to some embodiments of the present application. Figure 7 FIG. 8 is a sectional view of a partial structure of the bone conduction sound device shown in

[0169] Figure 7 The bone conduction sound device 700 shown in Figure 5 The bone conduction sound device 700 shown in Figure 7 The vibration unit of the bone conduction sound device 700 shown in

[0170] As shown in Figure 7 and Figure 30 The bone conduction sound device 700 can include a base structure 710 and a laminated structure, and at least part of the laminated structure is connected to the base structure 710. In some embodiments, the base structure 710 can be a frame structure with an internal hollow, and part of the laminated structure can be located in the hollow part of the frame structure. It should be noted that the frame structure is not limited to the cuboid shape shown in Figure 7 In some embodiments, the frame structure can be a prism, a cylinder, or other regular or irregular structures.

[0171] In some embodiments, the laminated structure can include an acoustic transduction unit 720 and a vibration unit. In some embodiments, the vibration unit can be arranged on the upper surface or the lower surface of the acoustic transduction unit 720. As shown in Figure 7As shown, the vibration unit includes a suspended membrane structure 730 and a mass element 740, which can be located on the upper or lower surface of the suspended membrane structure 730. In some embodiments, the suspended membrane structure 730 can be located on the upper or lower surface of the substrate structure 710. In some embodiments, the periphery of the suspended membrane structure 730 can also be connected to the inner wall of the hollow portion of the substrate structure 710. Here, "connection" can be understood as fixing the suspended membrane structure 730 to the upper or lower surface of the substrate structure 710 or the sidewall of the hollow portion of the substrate structure 710 by mechanical fixing (e.g., strong bonding, riveting, clamping, embedding, etc.) after the suspended membrane structure 730 and the substrate structure 710 are respectively prepared; or depositing the suspended membrane structure 730 on the substrate structure 710 by physical deposition (e.g., physical vapor deposition) or chemical deposition (e.g., chemical vapor deposition) during the preparation process.

[0172] In some embodiments, the shape of the suspension structure 730 can be circular, elliptical, or polygonal, such as triangular, quadrilateral, pentagonal, or hexagonal, or any other arbitrary shape. Preferably, as Figures 31A-31C As shown, the membrane structure 730 is circular. More information about the membrane structure 730 can be found in [link to relevant documentation]. Figure 5 The description of the suspended membrane structure 530 will not be repeated here.

[0173] In some embodiments, the mass of the laminated structure may include the mass element 740. When the vibrating unit moves relative to the base structure 710, the mass element 740 and the suspension structure 730 have different weights. The deformation of the area on the suspension structure 730 where the mass element 740 is located or near it is greater than the deformation of the area on the suspension structure 730 away from the mass element 740. To increase the output sound pressure of the bone conduction sound transmission device 700, the acoustic transducer unit 720 may be distributed circumferentially along the mass element 740. In some embodiments, the shape of the acoustic transducer unit 720 may be the same as or different from the shape of the mass element 740. Preferably, the shape of the acoustic transducer unit 720 may be the same as the shape of the mass element 740, so that each position of the acoustic transducer unit 720 can be close to the mass element 740, thereby further improving the output electrical signal of the bone conduction sound transmission device 700. For example, the mass element 740 has a cylindrical structure, and the acoustic transducer unit 720 can have a ring-shaped structure. The inner diameter of the ring-shaped acoustic transducer unit 720 is larger than the radius of the mass element 740, so that the acoustic transducer unit 720 is arranged along the circumference of the mass element 740. It should be noted that in this application, the shape and size of the acoustic transducer unit 720 and the mass element 740 are the shape and size of the cross-section perpendicular to the thickness direction.

[0174] In some embodiments, the acoustic transducing unit 720 can include a first electrode layer 721 and a second electrode layer 723, and a piezoelectric layer 722 between the two electrode layers, the first electrode layer 721, the piezoelectric layer 722 and the second electrode layer 723 combine into a structure body that is shaped to fit the mass element 740. For example, the mass element 740 is a cylindrical structure, the acoustic transducing unit 720 can be a ring structure, at this time the first electrode layer 721, the piezoelectric layer 722 and the second electrode layer 723 are all ring structures, and are sequentially arranged from top to bottom to combine into a ring structure.

[0175] In some embodiments, the shape of the acoustic transducing unit 720 can be a circular ring, a polygonal ring, a curved ring. For example, as shown in FIG. 7A, the shape of the acoustic transducing unit 720 is a circular ring. For another example, as shown in FIG. 7B, the shape of the acoustic transducing unit 720 is a regular hexagonal ring. For another example, as shown in FIG. 7C, the shape of the acoustic transducing unit 720 is a regular quadrilateral ring. In some embodiments, the shape of the acoustic transducing unit 720 can be a closed ring, an open ring, a multi-segment ring. For example, as shown in FIG. 7D, the shape of the acoustic transducing unit 720 is a closed ring. For another example, as shown in FIG. 7E, the shape of the acoustic transducing unit 720 is a circular two-segment ring. Preferably, as shown in FIG. 7F, the shape of the acoustic transducing unit 720 is a circular closed ring. Figures 31A-31C Figure 32A Figures 32C-32D Figure 32A Figure 32B Figures 31A-31C

[0176] In some embodiments, the inner diameter size and the outer diameter size of the acoustic transducing unit 720 can affect the resonant frequency of the vibration system. In some embodiments, the inner diameter size of the acoustic transducing unit 720 can be 100um-700um. In some embodiments, the outer diameter size of the acoustic transducing unit 720 can be 110um-710um. The inner diameter size and the outer diameter size of the acoustic transducing unit 720 are similar to the inner diameter size and the outer diameter size of the acoustic transducing unit 520, which can be referred to in detail in the related content of Figure 5

[0177] ​​​​​​​In some embodiments, the outer diameter dimension of the acoustic transducing unit 720 can be less than, equal to, or greater than the dimension of the cross section perpendicular to the thickness direction on the mass element 740. In some embodiments, the inner diameter dimension of the acoustic transducing unit 720 can be less than, equal to, or greater than the dimension of the cross section perpendicular to the thickness direction on the mass element 740. Preferably, the cross section perpendicular to the thickness direction on the mass element 740 is circular, and the inner diameter dimension of the acoustic transducing unit 720 is slightly greater than the diameter of the cross section perpendicular to the thickness direction on the mass element 740. In some embodiments, the inner diameter dimension of the acoustic transducing unit 720 is greater than the diameter of the cross section perpendicular to the thickness direction on the mass element 740, and the difference between the inner diameter dimension of the acoustic transducing unit 720 and the diameter of the cross section perpendicular to the thickness direction on the mass element 740 can be 5um-200um. In some embodiments, the inner diameter dimension of the acoustic transducing unit 720 is greater than the diameter of the mass element by 10um-180um. In some embodiments, the inner diameter dimension of the acoustic transducing unit 720 is greater than the diameter of the mass element by 20um-160um. In some embodiments, the inner diameter dimension of the acoustic transducing unit 720 is greater than the diameter of the mass element by 30um-140um. In some embodiments, the inner diameter dimension of the acoustic transducing unit 720 is greater than the diameter of the mass element by 40um-120um.

[0178] In some embodiments, the outer diameter dimension of the acoustic transducing unit 720 can be less than, equal to, or greater than the dimension of the hollow cavity of the base structure. In some embodiments, the inner diameter dimension of the acoustic transducing unit 720 can be less than, equal to, or greater than the dimension of the hollow cavity of the base structure. The hollow cavity of the base structure is similar to the hollow cavity of the base structure 510, which can be found in Figure 5 , and will not be further described herein. Preferably, the outer diameter dimension of the acoustic transducing unit 720 is less than the dimension of the hollow cavity of the base structure. In some embodiments, the outer diameter dimension of the acoustic transducing unit 720 is less than the dimension of the hollow cavity of the base structure, and the difference between the dimension of the hollow cavity of the base structure and the outer diameter dimension of the acoustic transducing unit 720 can be 5um-400um. The dimension of the acoustic transducing unit 720 and the hollow cavity of the base structure can be found in Figure 5 , and will not be further described herein.

[0179] In some embodiments, the mass element 740 can be one or more. In some embodiments, the plurality of mass elements 740 can be uniformly arranged along the inner side of the acoustic transducing unit 720. In some embodiments, the mass element 740 can be cylindrical, polygonal, spherical, or irregularly shaped. For example, as shown in Figure 32A , the mass element 740 is a regular hexagonal prism. For example, as shown in Figure 32B , the mass element 740 is a cylinder. For example, as shown in Figures 32C-32DAs shown, the mass element 740 is a quadrangular prism. It should be noted that the description of the shape of each component in the bone conduction sound transmission device in this specification can be the external shape of each component, or the shape of the cross section of each component perpendicular to the thickness direction.

[0180] In some embodiments, the mass element 740 is a cylinder, and the radius of the cross section of the mass element 740 perpendicular to the thickness direction can be 100-700 um. In some embodiments, the radius of the cross section of the mass element 740 perpendicular to the thickness direction is 120-600 um. In some embodiments, the radius of the cross section of the mass element 740 perpendicular to the thickness direction is 140-500 um. In some embodiments, the radius of the cross section of the mass element 740 perpendicular to the thickness direction is 160-400 um. In some embodiments, the radius of the cross section of the mass element 740 perpendicular to the thickness direction is 200-350 um. In some embodiments, the axial thickness (or the thickness along the thickness direction) of the mass element 740 can be 20-400 um. In some embodiments, the axial thickness can be 25-300 um. In some embodiments, the axial thickness can be 30-200 um. In some embodiments, the axial thickness can be 35-150 um.

[0181] In some embodiments, the mass element 740 can be a single-layer structure or a multi-layer structure. In some embodiments, when the mass element 740 is a single-layer structure, the mass element 740 can be made of a single material. In some embodiments, the single material can include, but is not limited to, any one of silicon-based materials such as single crystal silicon, polycrystalline silicon, silicon dioxide, silicon nitride, silicon carbide, etc. Preferably, the mass element 740 can be single crystal silicon or polycrystalline silicon. In some embodiments, when the mass element 740 is a multi-layer structure, the mass element 740 can be made of multiple materials. In some embodiments, the multiple materials can include, but are not limited to, two or more of silicon-based materials such as single crystal silicon, polycrystalline silicon, silicon dioxide, silicon nitride, silicon carbide, etc.

[0182] In some embodiments, the acoustic transducing unit 720 and the mass element 740 can be located on different sides of the suspension membrane structure 730, or on the same side of the suspension membrane structure 730. For example, the acoustic transducing unit 720 and the mass element 740 can both be located on the upper surface or the lower surface of the suspension membrane structure 730, and the acoustic transducing unit 720 can be distributed along the circumference of the mass element 740. For another example, the acoustic transducing unit 720 can be located on the upper surface of the suspension membrane structure 730, and the mass element 740 can be located on the lower surface of the suspension membrane structure 730, and the projection of the mass element 740 at the suspension membrane structure 730 can be within the area of the acoustic transducing unit 720. For yet another example, the acoustic transducing unit 720 can be located on the lower surface of the suspension membrane structure 730, and the mass element 740 can be located on the upper surface of the suspension membrane structure 730, and the projection of the mass element 740 at the suspension membrane structure 730 can be within the area of the acoustic transducing unit 720.

[0183] In some embodiments, the mass element 740 can be coaxial with the acoustic transducing unit 720 or the hollow cavity of the base structure 710. For example, as shown in FIG. 7A, the mass element 740 can be coaxial with the acoustic transducing unit 720. In some embodiments, the mass element 740 can be non-coaxial with the acoustic transducing unit 720 or the hollow cavity of the base structure 710. For example, as shown in FIG. 7B, the mass element 740 can be non-coaxial with the acoustic transducing unit 720. Figures 31A-31B Figure 31C In some embodiments, the mass element 740 can be coaxial with the acoustic transducing unit 720 or the hollow cavity of the base structure 710. For example, as shown in FIG. 7A, the mass element 740 can be coaxial with the acoustic transducing unit 720. In some embodiments, the mass element 740 can be non-coaxial with the acoustic transducing unit 720 or the hollow cavity of the base structure 710. For example, as shown in FIG. 7B, the mass element 740 can be non-coaxial with the acoustic transducing unit 720. Figure 31C In some embodiments, the mass element 740 can be coaxial with the acoustic transducing unit 720 or the hollow cavity of the base structure 710. For example, as shown in FIG. 7A, the mass element 740 can be coaxial with the acoustic transducing unit 720. In some embodiments, the mass element 740 can be non-coaxial with the acoustic transducing unit 720 or the hollow cavity of the base structure 710. For example, as shown in FIG. 7B, the mass element 740 can be non-coaxial with the acoustic transducing unit 720.

[0184] In some embodiments, the mass element 740 can be fabricated on a substrate material (same material as the base structure 710) by photolithography, etching, or the like. Further, the substrate material with the mass element 740 can be wafer bonded with the substrate material with the suspended membrane structure 730 and the base structure 710. In some embodiments, the bonding area can be the area of the mass element 740. In other embodiments, the bonding area can include the area of the mass element 740 and a portion of the base structure 710, provided that the acoustic transducing unit and the pad area holes on the base structure 710 are not blocked. In some embodiments, the area of the bonding area on the base structure 710 can account for 10%-90% of the area of the base structure 710 in a cross section perpendicular to the thickness direction. In some embodiments, a wafer thinning process can be used to remove the excess material on the substrate material with the mass element 740. In other embodiments, the mass element 740 can be further fabricated on the substrate material with the acoustic transducing unit 720. Specifically, a spin coating and photolithography development process can be performed on the other side of the substrate material with the acoustic transducing unit 720 (the opposite side of the substrate material with the acoustic transducing unit 720), and then a deep silicon etching process can be used to etch to a certain depth. Then a further deep silicon etching process can be used to etch the mass element 740.

[0185] In some embodiments, an etching stop layer can be fabricated on the substrate material, which can facilitate the accurate control of the size of the electrode layer (e.g., the first electrode layer or the second electrode layer), and can also prevent the substrate material from being damaged by the subsequent etching process. Specifically, the etching stop layer can be fabricated on the substrate material by chemical vapor deposition (CVD) or thermal oxidation, or the like. In some embodiments, the etching stop layer can have a thickness of 100 nm-2 um, and in some embodiments, the etching stop layer can have a thickness of 300 nm-1 um. In some embodiments, the etching stop layer can be removed by photolithography and etching to obtain the bone conduction sound device.

[0186] In some embodiments, the output electrical signal of the bone conduction sound device 700 can be improved by changing the size, shape, and position of the mass element 740, as well as the position, shape, and size of the piezoelectric layer. In some embodiments, the sound pressure output effect of the bone conduction sound device 700 can also be improved by changing the shape, material, and size of the suspended membrane structure 730. Here, the first electrode layer 721, the second electrode layer 723, and the piezoelectric layer 722 of the acoustic transducing unit 720 are similar to the first electrode layer 521, the second electrode layer 523, and the piezoelectric layer 522 of the acoustic transducing unit 520 in the bone conduction sound device 500, the suspended membrane structure 730 is similar to the suspended membrane structure 530, and the lead structure 7200 is similar to the lead structure 5200. Figure 5 ​

[0187] In some embodiments, the acoustic transducer unit 720 is further provided with a lead structure 7200, which is used to transmit the electrical signals collected by the electrode rings (e.g., the first electrode layer 721 and the second electrode layer 723) to subsequent circuits. In some embodiments, the first electrode layer 721 and the second electrode layer 723 are connected to the substrate structure 710 through the lead structure 7200. Specifically, the lead structure 7200 includes a first lead and a second lead, one end of the first lead is connected to the first electrode layer 721 and the other end of the first lead is connected to the substrate structure; one end of the second lead is connected to the second electrode layer 723 and the other end of the second lead is connected to the substrate structure.

[0188] In some embodiments, the equivalent stiffness and equivalent mass of the bone conduction sound transmission device 500 can be adjusted by adjusting the shape, size (e.g., length, width, thickness) and material of the lead wire structure 7200, thereby improving the output electrical signal of the bone conduction sound transmission device 700 and thus enhancing the sensitivity of the bone conduction sound transmission device 500.

[0189] In some embodiments, the lead structure 7200 may include a straight line, a broken line, or a curve. For example, as... Figures 31A-31C As shown, the lead structure 7200 is a straight line. For example, as... Figure 33A As shown, the lead structure 7200 is curved. For example, as... Figure 33B As shown, the lead structure 7200 is a broken line. In some embodiments, the width of the lead structure 7200 can be 10um-100um. In some embodiments, the width is 15um-90um. In some embodiments, the width is 20um-80um.

[0190] Figure 34 This is a schematic diagram of the lead structure in another bone conduction sound transmission device according to some embodiments of this application. In some embodiments, such as Figure 34 As shown, the first electrode layer 721 is connected to the pad 7210 via a lead structure 7200. The pad 7210 can be located on the upper surface, lower surface, or side of the substrate structure 710, such as... Figure 34 As shown, the pad 7210 can be located on the upper surface of the substrate structure 710, used to derive electrical signals between the acoustic transducer unit 720 and the housing, lead structure 7200, etc. By connecting the first electrode layer 721 to the pad 7210 through the lead structure 7200, the electrical signal between the acoustic transducer unit 720 and the housing, lead structure 7200 can be reduced, thereby reducing parasitic capacitance and improving the sensitivity of the bone conduction sound transmission device 700. In some embodiments, the pad 7210 can be circular, elliptical, triangular, polygonal, or irregular in shape. Further description of the pad 7210 can be found in [reference needed]. Figure 5 The contents of pad 5210 will not be elaborated here.

[0191] Figure 7 The first electrode layer 721, the second electrode layer 723 and the piezoelectric layer 722 of the acoustic transducing unit 720 in the structure shown in Figure 5 The structure and parameters of the first electrode layer 521, the second electrode layer 523 and the piezoelectric layer 522 of the acoustic transducing unit 520 in the structure shown in are similar to those of the acoustic transducing unit 520 in the structure shown in, the structure and parameters of the suspension membrane structure 730 are similar to those of the suspension membrane structure 530, and the structure of the lead structure 7200 is similar to that of the lead structure 5200. For details, please refer to the related description in Figure 5 , which will not be described further here.

[0192] The structures in one or more embodiments described above can be combined with each other. For example, the vibration unit can include a suspension membrane structure and a mass unit, and the suspension membrane structure includes at least one hole. For details, please refer to the structures shown in Figure 35 and Figure 36 .

[0193] Figure 35 is a structural schematic diagram of a bone conduction sound transducing device according to some embodiments of the present application; Figure 36 is a cross-sectional view of a partial structure of the bone conduction sound transducing device shown in Figure 35 . As shown in Figure 35 and Figure 36 , the bone conduction sound transducing device 3500 can include a base structure 3510 and a laminated structure, wherein at least part of the laminated structure is connected with the base structure 3510. In some embodiments, the base structure 3510 can be a frame structure with an internal hollow, and part of the laminated structure can be located in the hollow part of the frame structure. It should be noted that the frame structure is not limited to the cuboid shape shown in Figure 35 . In some embodiments, the frame structure can be a regular or irregular structure such as a prism or a cylinder.

[0194] In some embodiments, the laminated structure can include an acoustic transducing unit 3520 and a vibration unit. As shown in Figure 35 , the vibration unit includes a suspension membrane structure 3530, which is fixed on the base structure 3510 by being connected with the base structure 3510 through the peripheral side, and the central region of the suspension membrane structure 3530 is suspended in the hollow part of the base structure 3510. In some embodiments, the suspension membrane structure 3530 can be located on the upper surface or the lower surface of the base structure 3510. In some embodiments, the peripheral side of the suspension membrane structure 3530 can also be connected with the inner wall of the hollow part of the base structure 3510.

[0195] In some embodiments, the suspended membrane structure 3530 can include at least one elastic layer. The elastic layer can be a membrane-shaped structure made of a semiconductor material. In some embodiments, the semiconductor material can include silicon dioxide, silicon nitride, gallium nitride, zinc oxide, silicon carbide, monocrystalline silicon, polycrystalline silicon, etc. In some embodiments, the suspended membrane structure 3530 can include a plurality of holes 35300 distributed around the center of the acoustic transducing unit 3520 along the circumferential direction (e.g., the outer circumferential direction and / or the inner circumferential direction) of the acoustic transducing unit 3520. The structure and parameters of the suspended membrane structure 3530 are similar to those of the suspended membrane structure 530, and details are described in the related content of Figure 5 , which will not be described further here.

[0196] In some embodiments, the acoustic transducing unit 3520 can be located on the upper surface or the lower surface of the suspended membrane structure 3530. For example, as shown in Figures 35-36 , the acoustic transducing unit 3520 can be located on the upper surface of the suspended membrane structure 3530. In combination with Figure 35 and Figure 36 , in some embodiments, the acoustic transducing unit 3520 can include a first electrode layer 3521, a piezoelectric layer 3522, and a second electrode layer 3523 arranged in order from top to bottom, wherein the positions of the first electrode layer 3521 and the second electrode layer 3523 can be interchanged. The structure and parameters of the acoustic transducing unit 3520 are similar to those of the acoustic transducing unit 520 or the acoustic transducing unit 720, and details are described in the related content of Figure 5 or Figure 7 , which will not be described further here.

[0197] In some embodiments, the vibration unit can also include a mass element 3540 Figure 35 (not shown in the figure), which can be located on the upper surface or the lower surface of the suspended membrane structure 3530. For example, as shown in Figure 36 , the mass element 3540 can be located on the lower surface of the suspended membrane structure 3530. The structure and parameters of the mass element 3540 are similar to those of the mass element 740, and details are described in the related content of Figure 7 , which will not be described further here.

[0198] Based on one or more of the foregoing embodiments, the resonance frequency curves of the bone conduction sound transducing device with multiple circular holes arranged on the suspended membrane structure and the bone conduction sound transducing device with a mass element arranged below the suspended membrane structure are respectively described below. Figure 37 and Figure 38 . It should be noted that Figure 37 and Figure 38The structure of the corresponding bone conduction microphone is only for illustrating that the resonant frequency of the bone conduction microphone can be adjusted by setting holes in the diaphragm structure and setting the mass element, and does not limit the protection scope of the present application.

[0199] Figure 37 is a resonant frequency curve of a bone conduction microphone according to some embodiments of the present application; Figure 38 is another resonant frequency curve of a bone conduction microphone according to some embodiments of the present application. It should be noted that the resonant frequency curve is a frequency response curve. Figure 37 The bone conduction microphone corresponding to the resonant frequency curve in Figure 28 The circular diaphragm structure and the plurality of circular holes in form a circular structure. The number of holes is 2-18, and the holes are circularly distributed in one or two circles. The radius of the holes is 20-300 um, and the radius of the circle formed by the holes is 300-700 um. The thickness of the diaphragm structure is 0.5-10 um. The shape of the diaphragm structure is circular, and the radius of the diaphragm structure is 500-1500 um. The acoustic transducing unit is a circular closed ring, and the inner diameter is 100-700 um, and the outer diameter is 110-710 um. Figure 38 The bone conduction microphone corresponding to the resonant frequency curve in Figure 31A The structure of the circular diaphragm structure and the circular mass element in, wherein the number of mass elements is 1-3, the shape of the mass element is cylindrical, the thickness of the mass element is 20-400 um, the radius of the cross section of the mass element perpendicular to the thickness direction is 100-700 um, and the mass element is coaxially arranged with the acoustic transducing unit. The thickness of the diaphragm structure is 0.5-10 um. The shape of the diaphragm structure is circular, and the radius of the diaphragm structure is 500-1500 um. The acoustic transducing unit is a circular closed ring, and the inner diameter is 100-700 um, and the outer diameter is 110-710 um.

[0200] From Figure 37 It can be known from that the resonant frequency range is 2-5 kHz (the peak of the resonant frequency is at 3.8 kHz), and from Figure 38 It can be known from that the resonant frequency range is 3-5.5 kHz (the peak of the resonant frequency is at 4.5 kHz). By adjusting the number, size, and distribution position of the holes, and the size, shape, position, and weight of the mass element, the resonant frequency of the bone conduction microphone can be adjusted within 3-4.5 kHz, and the output electric signal of the bone conduction microphone is adjusted, and the sensitivity of the bone conduction microphone is improved.

[0201] Figure 8 is a structural schematic diagram of a bone conduction microphone according to some embodiments of the present application; Figure 9 isFigure 8 A cross-sectional view of the bone conduction sound transmission device at point C. Figure 8 As shown, the substrate structure 810 is a cuboid frame structure. In some embodiments, the interior of the substrate structure 810 may include a hollow portion for housing the acoustic transducer unit 820 and the vibration unit. In some embodiments, the hollow portion may be circular, quadrilateral (e.g., rectangle, parallelogram), pentagonal, hexagonal, heptagonal, octagonal, or other regular or irregular shapes. In some embodiments, the dimension of one side of the rectangular cavity may be 0.8mm-2mm. Preferably, the dimension of one side of the rectangular cavity may be 1mm-1.5mm. In some embodiments, the vibration unit may include four support arms 830 and a mass element 840. One end of the four support arms 830 is connected to the upper surface, lower surface, or sidewall of the hollow portion of the substrate structure 810, and the other end of the four support arms 830 is connected to the upper surface, lower surface, or circumferential sidewall of the mass element 840. In some embodiments, the mass element 840 may protrude upward and / or downward relative to the support arms 830. For example, when the ends of the four support arms 830 are connected to the upper surface of the mass element 840, the mass element 840 may protrude downward relative to the support arms 830. As another example, when the ends of the four support arms 830 are connected to the lower surface of the mass element 840, the mass element 840 may protrude upward relative to the support arms 830. Yet another example, when the ends of the four support arms 830 are connected to the circumferential sidewalls of the mass element 840, the mass element 840 may protrude both upward and downward relative to the support arms 830. In some embodiments, the support arms 830 are trapezoidal in shape, wherein the narrower end of the support arm 830 is connected to the mass element 840, and the wider end of the support arm 830 is connected to the base structure 810.

[0202] In some embodiments, the support arm 830 can include at least one elastic layer. The elastic layer can be a plate-shaped structure made of a semiconductor material. In some embodiments, the semiconductor material can include silicon, silicon dioxide, silicon nitride, gallium nitride, zinc oxide, silicon carbide, etc. In some embodiments, the materials of different elastic layers of the support arm 830 can be the same or different. Further, the bone conduction sound transmission device 800 can include an acoustic transduction unit 820. The acoustic transduction unit 820 can include a first electrode layer 821, a piezoelectric layer 822, and a second electrode layer 823 arranged in order from top to bottom, and the first electrode layer 821 or the second electrode layer 823 is connected to the upper surface or the lower surface of the support arm 830 (e.g., the elastic layer). In some embodiments, when the support arm 830 is a plurality of elastic layers, the acoustic transduction unit 820 can also be located between the plurality of elastic layers. The piezoelectric layer 822 can generate a voltage (potential difference) based on the piezoelectric effect under the deformation stress of the vibration unit (e.g., the support arm 830 and the mass element 840), and the first electrode layer 821 and the second electrode layer 823 can guide the voltage (electric signal) out. In order to make the resonance frequency of the bone conduction sound transmission device 800 within a certain frequency range (e.g., 2000 Hz-5000 Hz), the materials and thicknesses of the acoustic transduction unit 820 (e.g., the first electrode layer 821, the second electrode layer 823, and the piezoelectric layer 822), the vibration unit (e.g., the support arm 830) can be adjusted to achieve. In some embodiments, the acoustic transduction unit 820 can also include a pad layer, which can be located on the first electrode layer 821 and the second electrode layer 823, and the first electrode layer 821 and the second electrode layer 823 are connected to the external circuit through the external wire (e.g., gold wire, aluminum wire, etc.), so as to guide the voltage signal between the first electrode layer 821 and the second electrode layer 823 to the back-end processing circuit. In some embodiments, the material of the pad layer can include copper foil, titanium, copper, etc. In some embodiments, the thickness of the pad layer can be 100 nm-200 nm. Preferably, the thickness of the pad layer can be 150 nm-200 nm. In some embodiments, the acoustic transduction unit 820 can also include a seed layer, which can be located between the second electrode layer 823 and the support arm 830. In some embodiments, the material of the seed layer can be the same as the material of the piezoelectric layer 822. For example, when the material of the piezoelectric layer 822 is AlN, the material of the seed layer is also AlN. In some embodiments, the material of the seed layer can also be different from the material of the piezoelectric layer 822. It should be noted that the specific frequency range of the resonance frequency of the above bone conduction sound transmission device 800 is not limited to 2000 Hz-5000 Hz, but can also be 4000 Hz-5000 Hz, or 2300 Hz-3300 Hz, etc. The specific frequency range can be adjusted according to actual conditions.In addition, when the mass element 840 protrudes upward relative to the support arm 830, the acoustic transducing unit 820 can be located on the lower surface of the support arm 830, and the seed layer can be located between the mass element 840 and the support arm 830.

[0203] In some embodiments, the mass element 840 can be a single-layer structure or a multi-layer structure. In some embodiments, the mass element 840 is a multi-layer structure, and the number of layers of the mass element 840, the corresponding materials of each layer structure, and the parameters can be the same as or different from those of the elastic layer of the support arm 830 and the acoustic transducing unit 820. In some embodiments, the shape of the mass element 840 can be a regular or irregular shape such as a circular shape, a semicircular shape, an elliptical shape, a triangular shape, a quadrilateral shape, a pentagonal shape, a hexagonal shape, a heptagonal shape, an octagonal shape, etc. In some embodiments, the thickness of the mass element 840 can be the same as or different from the total thickness of the support arm 830 and the acoustic transducing unit 820. The materials and dimensions of the mass element 840 when being a multi-layer structure can be referred to the elastic layer of the support arm 830 and the acoustic transducing unit 820, which will not be repeated here. In addition, the materials and parameters of each layer structure of the elastic layer and the acoustic transducing unit 820 can also be applied to the mass element 840. Figure 1 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 7 The bone conduction sound transmission device shown in FIG. 8.

[0204] In some embodiments, the acoustic transducing unit 820 can at least include an effective acoustic transducing unit. An effective acoustic transducing unit refers to a partial structure of the acoustic transducing unit that contributes to the final electrical signal. For example, the first electrode layer 821, the piezoelectric layer 822, and the second electrode layer 823 have the same shape and area and partially cover the support arm 830 (elastic layer), and the first electrode layer 821, the piezoelectric layer 822, and the second electrode layer 823 are effective transducing units. For another example, the first electrode layer 821 and the piezoelectric layer 822 partially cover the support arm 830, and the second electrode layer 823 fully covers the support arm 830, and the first electrode layer 821 and the piezoelectric layer 822 corresponding to the first electrode layer 821 and the second electrode layer 823 corresponding to the first electrode layer 821 form an effective acoustic transducing unit. For another example, the first electrode layer 821 partially covers the support arm 830, and the piezoelectric layer 822 and the second electrode layer 823 fully cover the support arm 830, and the first electrode layer 821, the piezoelectric layer 822 corresponding to the first electrode layer 821, and the second electrode layer 823 corresponding to the first electrode layer 821 form an effective transducing unit. For another example, the first electrode layer 821, the piezoelectric layer 822, and the second electrode layer 823 fully cover the support arm 830, but the first electrode layer 821 is divided into multiple independent electrodes by the insulation channel (for example, the electrode insulation channel 8200), and the independent electrode part of the first electrode layer 821 from which the electrical signal is led out and the piezoelectric layer 822 and the second electrode layer 823 corresponding to the independent electrode part of the first electrode layer 821 form an effective transducing unit. The independent electrode area of the first electrode layer 821 from which the electrical signal is not led out and the piezoelectric layer 822 and the second electrode layer 823 corresponding to the independent electrode and the insulation channel of the first electrode layer 821 do not provide an electrical signal and mainly provide a mechanical action. In order to improve the signal-to-noise ratio of the bone conduction sound transmission device 800, the effective acoustic transducing unit can be arranged at the position close to the mass element 840 or close to the connection between the support arm 830 and the base structure 810. Preferably, the effective acoustic transducing unit is arranged at the position close to the mass element 840 of the support arm 830. In some embodiments, when the effective acoustic transducing unit is arranged at the position close to the mass element 840 or close to the connection between the support arm 830 and the base structure 810, the ratio of the coverage area of the effective acoustic transducing unit at the support arm 830 to the area of the support arm 830 is 5%-40%. Preferably, the ratio of the coverage area of the effective acoustic transducing unit at the support arm 830 to the area of the support arm 830 is 10%-35%. Further preferably, the ratio of the coverage area of the effective acoustic transducing unit at the support arm 830 to the area of the support arm 830 is 15%-20%.

[0205] The signal-to-noise ratio of the bone conduction sound transmission device 800 is positively correlated with the strength of the output electrical signal. When the relative motion occurs between the laminated structure and the base structure, the deformation stress at the connection between the support arm 830 and the mass element 840 and the connection between the support arm 830 and the base structure 810 is larger than the deformation stress at the middle region of the support arm 830. Correspondingly, the strength of the output voltage at the connection between the support arm 830 and the mass element 840 and the connection between the support arm 830 and the base structure 810 is also larger than the strength of the output voltage at the middle region of the support arm 830. In some embodiments, in order to improve the signal-to-noise ratio of the bone conduction sound transmission device 800, an electrode insulation channel 8200 can be arranged on the first electrode layer 821 when the acoustic transduction unit 820 completely or nearly completely covers the upper surface or the lower surface of the support arm 830. The electrode insulation channel 8200 separates the first electrode layer 821 into two parts, so that one part of the first electrode layer 821 is close to the mass element 840, and the other part of the first electrode layer 821 is close to the connection between the support arm 830 and the base structure 810. The part of the first electrode layer 821, the corresponding piezoelectric layer 822 and the second electrode layer 823 separated by the electrode insulation channel 8200 and from which the electrical signal is led out are effective acoustic transduction units. In some embodiments, the electrode insulation channel 8200 can be a straight line extending along the width direction of the support arm 830. In some embodiments, the width of the electrode insulation channel 8200 can be 2um-20um. Preferably, the width of the electrode insulation channel 8200 can be 4um-10um.

[0206] It should be noted that the electrode insulation channel 8200 is not limited to a straight line extending along the width direction of the support arm 830, but can also be a curve, a bent line, a wavy line, etc. In addition, the electrode insulation channel 8200 can also not extend along the width direction of the support arm 830, for example Figure 10 As shown in the electrode insulation channel 8201, the electrode insulation channel 8200 can only separate the acoustic transduction unit 820 into multiple parts, which is not limited further herein.

[0207] As shown in the electrode insulation channel 8201, the electrode insulation channel 8200 can only separate the acoustic transduction unit 820 into multiple parts, which is not limited further herein. Figure 10 As shown in the electrode insulation channel 8201, the electrode insulation channel 8200 can only separate the acoustic transduction unit 820 into multiple parts, which is not limited further herein. Figure 10When the acoustic transduction unit between the middle electrode insulating channel 8201 and the mass element 840 is arranged at the position of the support arm 830 close to the mass element 840, the first electrode layer 821 and / or the second electrode layer 823 can further include an electrode lead. Taking the first electrode layer 821 as an example, the electrode insulating channel 8201 separates the first electrode layer 821 into two parts, one part of the first electrode layer 821 is connected to or close to the mass element 840, and the other part of the first electrode layer 821 is close to the connection between the support arm 830 and the base structure 810. In order to output the voltage close to the mass element 840 of the acoustic transduction unit 820, the first electrode layer 821 close to the connection between the support arm 830 and the base structure 810 can be separated into a partial area (the first electrode layer 821 shown in the figure is located at the edge area of the support arm 830) by the electrode insulating channel 8201, and the partial area electrically connects the part of the acoustic transduction unit 820 connected to or close to the mass element 840 to the processing unit of the bone conduction microphone 800. In some embodiments, the width of the electrode lead can be 4um-20um. Preferably, the width of the electrode lead can be 4um-10um. In some embodiments, the electrode lead can be located at any position in the width direction of the support arm 830, for example, the electrode lead can be located at the center of the support arm 830 or close to the edge in the width direction. Preferably, the electrode lead can be located close to the edge in the width direction of the support arm 830. By arranging the electrode lead 8211, the use of conductive wires in the acoustic transduction unit 820 can be avoided, and the structure is relatively simple, which is convenient for subsequent production and assembly.

[0208] Considering that the piezoelectric material of the piezoelectric layer 822 can cause surface roughness due to etching in the area close to the edge of the support arm 830, which can cause poor quality of the piezoelectric material, in some embodiments, when the area of the piezoelectric layer 822 is the same as the area of the second electrode layer 823, in order to make the first electrode layer 821 be located in the area of the piezoelectric material with good quality, the area of the piezoelectric layer 822 can be smaller than the area of the first electrode layer 821, so that the edge area of the first electrode layer 821 avoids the edge area of the piezoelectric layer 822, and an electrode recess channel (not shown in the figure) can be formed between the first electrode layer 821 and the piezoelectric layer 822. By arranging the electrode recess channel, the area of the piezoelectric layer 822 with poor quality at the edge can be avoided from the first electrode layer 821 and the second electrode layer 823, thereby improving the signal-to-noise ratio of the output bone conduction microphone. In some embodiments, the width of the electrode recess channel can be 2um-20um. Preferably, the width of the electrode recess channel can be 2um-10um.

[0209] As Figure 10As shown, the acoustic transducing unit 820 can further include an extension area 8210 extending along the length of the support arm 830, which is located on the upper surface of the mass element 840, as an example when the mass element 840 is protruded downward relative to the support arm 830. In some embodiments, the edge of the extension area 8210 on the upper surface of the mass element 840 can be provided with an electrode insulation channel 8201 to prevent excessive stress concentration on the support arm 830, thereby improving the stability of the support arm 830. In some embodiments, the length of the extension area 8210 is greater than the width of the support arm 830. Here, the length of the extension area 8210 corresponds to the width of the support arm 830. In some embodiments, the length of the extension area 8210 is 4-30 um. Preferably, the length of the extension area 8210 is 4-15 um. In some embodiments, the length of the extension area 8210 on the mass element 840 is 1.2-2 times the width of the support arm 830 at the edge connection part of the mass element 840. Preferably, the length of the extension area 8210 on the mass element 840 is 1.2-1.5 times the width of the support arm 830 at the edge connection part of the mass element 840.

[0210] Figure 11 is a structural schematic diagram of a bone conduction sound transducing device according to some embodiments of the present application. Figure 11 The bone conduction sound transducing device 1000 shown is substantially the same as the bone conduction sound transducing device 800 shown in Figure 8 The bone conduction sound transducing device 800 shown is substantially the same as the bone conduction sound transducing device 700 shown in Figure 11As shown, the base structure 1010 is a cuboid frame structure. In some embodiments, the interior of the base structure 1010 can include a hollow portion for suspending the acoustic transducing unit and the vibration unit. In some embodiments, the shape of the hollow portion can be circular, quadrilateral (e.g., rectangular, parallelogram), pentagonal, hexagonal, heptagonal, octagonal, or other regular or irregular shape. In some embodiments, the vibration unit can include four support arms 1030 and a mass element 1040, one end of the four support arms 1030 being connected to the upper surface, the lower surface of the base structure 1010, or the side wall of the base structure 1010 where the hollow portion is located, and the other end of the four support arms 1030 being connected to the upper surface, the lower surface, or the circumferential side wall of the mass element 1040. In some embodiments, the mass element 1040 can be convex upward and / or downward relative to the support arms 1030. For example, when the ends of the four support arms 1030 are connected to the upper surface of the mass element 1040, the mass element 1040 can be convex downward relative to the support arms 1030. For another example, when the ends of the four support arms 1030 are connected to the lower surface of the mass element 1040, the mass element 1040 can be convex upward relative to the support arms 1030. For yet another example, when the ends of the four support arms 1030 are connected to the circumferential side wall of the mass element 1040, the mass element 1040 can be convex upward and downward relative to the support arms 1030. In some embodiments, the shape of the support arms 1030 is rectangular, wherein one end of the support arms 1030 is connected to the mass element 1040, and the other end of the support arms 1030 is connected to the base structure 1010.

[0211] In some embodiments, in order to improve the signal-to-noise ratio of the bone conduction sound transmission device 1000, the effective acoustic transducing unit can be arranged at the position of the support arm 1030 close to the mass element 1040 or close to the connection between the support arm 1030 and the base structure 1010. Preferably, the effective acoustic transducing unit is arranged at the position of the support arm 1030 close to the mass element 1040. In some embodiments, when the effective acoustic transducing unit is arranged at the position of the support arm 1030 close to the mass element 1040 or close to the connection between the support arm 1030 and the base structure 1010, the ratio of the coverage area of the effective acoustic transducing unit to the area of the support arm 1030 at the position of the support arm 1030 is 5%-40%. Preferably, the ratio of the coverage area of the effective acoustic transducing unit to the area of the support arm 1030 at the position of the support arm 1030 is 10%-35%. Further preferably, the ratio of the coverage area of the effective acoustic transducing unit 1020 to the area of the support arm 1030 at the position of the support arm 1030 is 15%-20%.

[0212] The signal-to-noise ratio of the bone conduction sound transmission device 1000 is positively correlated with the strength of the output electric signal. When the relative motion occurs between the laminated structure and the base structure, the deformation stress at the connection between the support arm 1030 and the mass element 1040 and the connection between the support arm 1030 and the base structure 1010 is larger than the deformation stress at the middle region of the support arm 1030. Further, the strength of the output voltage at the connection between the support arm 1030 and the mass element 1040 and the connection between the support arm 1030 and the base structure 1010 is also larger than the strength of the output voltage at the middle region of the support arm 1030. In some embodiments, when the acoustic transduction unit completely or nearly completely covers the upper surface or the lower surface of the support arm 1030, in order to improve the signal-to-noise ratio of the bone conduction sound transmission device 1000, an electrode insulation channel 1050 can be arranged on the first electrode layer. The electrode insulation channel 1050 separates the first electrode layer into two parts, so that one part of the first electrode layer is close to the mass element 1040, and the other part of the first electrode layer is close to the connection between the support arm 1030 and the base structure 1010. In some embodiments, the electrode insulation channel 1050 can be a straight line extending along the width direction of the support arm 1030. In some embodiments, the width of the electrode insulation channel 1050 can be 2um-20um. Preferably, the width of the electrode insulation channel 1050 can be 4um-10um.

[0213] It should be noted that the electrode insulation channel 1050 is not limited to a straight line extending along the width direction of the support arm 1030, but can also be a curve, a bent line, a wavy line, etc. In addition, the electrode insulation channel 1050 can also not extend along the width direction of the support arm 1030, for example Figure 12 The electrode insulation channel 11200 shown in the figure, as long as the acoustic transduction unit can be separated into multiple parts, is not further limited here.

[0214] As Figure 12 shown, part of the structure of the acoustic transduction unit (for example, Figure 12When the acoustic transducing unit between the middle electrode insulating channel 11200 and the mass element 1140 is arranged at the position of the support arm 1130 close to the mass element 1140, the first electrode layer 1121 and / or the second electrode layer can further comprise an electrode lead. Taking the first electrode layer 1121 as an example, the electrode insulating channel 11200 separates the first electrode layer 1121 into two parts, one part of the first electrode layer 1121 is connected to or close to the mass element 1140, and the other part of the first electrode layer 1121 is close to the connection between the support arm 1130 and the base structure 1110. In order to output the voltage close to the mass element 1140 of the acoustic transducing unit, the first electrode layer 1121 close to the connection between the support arm 1130 and the base structure 1110 can be separated into a partial area (the first electrode layer 1121 shown in the figure is located at the edge area of the support arm 1130) by the electrode insulating channel 11200, and the partial area electrically connects the part of the acoustic transducing unit connected to or close to the mass element 1140 and the processing unit of the bone conduction sound device. In some embodiments, the width of the electrode lead can be 4um-20um. Preferably, the width of the electrode lead can be 4um-10um. In some embodiments, the electrode lead can be located at any position in the width direction of the support arm 1130, for example, the electrode lead can be located at the center or close to the edge in the width direction of the support arm 1130. Preferably, the electrode lead can be located close to the edge in the width direction of the support arm 1130. By arranging the electrode lead, the use of conductive wires in the acoustic transducing unit can be avoided, and the structure is relatively simple, which is convenient for subsequent production and assembly.

[0215] As shown in Figure 13 , the piezoelectric material of the piezoelectric layer close to the edge area of the support arm will cause surface roughness due to etching, which will cause the quality of the piezoelectric material to deteriorate. In some embodiments, when the area of the piezoelectric layer is the same as the area of the second electrode layer, in order to make the first electrode layer 1121 located in the area of the piezoelectric layer with better quality piezoelectric material, the area of the piezoelectric layer can be smaller than the area of the first electrode layer 1121, so that the edge area of the first electrode layer 1121 avoids the edge area of the piezoelectric layer, and the electrode recess channel 11212 can be formed between the first electrode layer 1121 and the piezoelectric layer. By arranging the electrode recess channel 11212, the area with poor quality of the piezoelectric layer edge can be avoided from the first electrode layer and the second electrode layer, thereby improving the signal-to-noise ratio of the output bone conduction sound device. In some embodiments, the width of the electrode recess channel 11212 can be 2um-20um. Preferably, the width of the electrode recess channel 11212 can be 2um-10um.

[0216] As shown in Figure 14As shown, in some embodiments, the acoustic transducing unit can further include an extension area 11210 extending along the length of the support arm 1130, which is located on the upper surface of the mass element 1140, as an example of the mass element 1140 being convex downward relative to the support arm 1130. In some embodiments, the edge of the extension area 11210 on the upper surface of the mass element 1140 can be provided with an electrode insulation channel 11200, so as to prevent the support arm 1130 from having excessive stress concentration, thereby improving the stability of the support arm 1130. In some embodiments, the length of the extension area 11210 is greater than the width of the support arm 1130. Here, the length of the extension area 11210 corresponds to the width of the support arm 1130. In some embodiments, the length of the extension area 11210 is 4-30 um. Preferably, the length of the extension area 11210 is 4-15 um. In some embodiments, the length of the extension area 11210 on the mass element 1140 is 1.2-2 times the width of the support arm 1130 at the edge connection with the mass element 1140. Preferably, the length of the extension area 11210 on the mass element 1140 is 1.2-1.5 times the width of the support arm 1130 at the edge connection with the mass element 1140. The materials, dimensions, and other parameters of the structures of the acoustic transducing unit, the first electrode layer, the second electrode layer, the piezoelectric layer, the vibration unit, the mass element 1140, and the like in the present embodiment can refer to the contents of Figures 8-10 , which will not be repeated here.

[0217] Figure 15 is a structural schematic diagram of another bone conduction sound transducing device according to some embodiments of the present application. Figure 15 The bone conduction sound transducing device 1500 is substantially the same as the bone conduction sound transducing device 800 shown in Figure 8 , except that the connection manner of the support arm and the base structure is different. As shown in Figures 8-10As shown, the base structure 1510 is a cuboid frame structure. In some embodiments, the interior of the base structure 1510 can include a hollow portion for suspending the acoustic transducing unit and the vibration unit. In some embodiments, the vibration unit can include four support arms 1530 and a mass element 1540, one end of the four support arms 1530 being connected with the upper surface, the lower surface of the base structure 1510 or the side wall where the hollow portion of the base structure 1510 is located, and the other end of the four support arms 1530 being connected with the upper surface, the lower surface or the circumferential side wall of the mass element 1540. In some embodiments, the mass element 1540 can be convex upward and / or downward relative to the support arms 1530. For example, when the ends of the four support arms 1530 are connected with the upper surface of the mass element 1540, the mass element 1540 can be convex downward relative to the support arms 1530. For another example, when the ends of the four support arms 1530 are connected with the lower surface of the mass element 1540, the mass element 1540 can be convex upward relative to the support arms 1530. For yet another example, when the ends of the four support arms 1530 are connected with the circumferential side wall of the mass element 1540, the mass element 1540 can be convex upward and downward relative to the support arms 1530. In some embodiments, the shape of the support arms 1530 is trapezoidal, where the end of the support arms 1530 connected with the mass element 1540 has a larger width, and the end of the support arms 1530 connected with the base structure 1510 has a smaller width. It should be noted that, Figure 16 The structure, size, thickness and other parameters of the components of the middle acoustic transducing unit 820, the first electrode layer 821, the second electrode layer 823, the piezoelectric layer 822, the vibration unit, the mass element 840, the extension region 8210, the electrode insulation channel 8201, the electrode recess channel, the electrode insulation channel 8200, etc. can be applied to the bone conduction sound transducing device 1500, and will not be further described here.

[0218] Figure 16 is a structural schematic diagram of a bone conduction sound transducing device provided according to some embodiments of the present application. Figure 8 The structure of the bone conduction sound transducing device 1600 shown is similar to Figures 8-10The structures of the bone conduction sound transmission devices 800 shown are substantially the same, and the difference is that the support arms 1630 of the bone conduction sound transmission device 1600 are different from the support arms 830 in the bone conduction sound transmission device 800. In some embodiments, the inside of the base structure 1610 can include a hollow portion for suspending the acoustic transducing unit and the vibration unit. In some embodiments, the vibration unit can include four support arms 1630, one end of the four support arms 1630 being connected to the upper surface, the lower surface of the base structure 1610, or the side wall of the base structure 1610 where the hollow portion is located, and the other end of the four support arms 1630 being connected to the upper surface, the lower surface, or the circumferential side wall of the mass element 1640. In some embodiments, the mass element 1640 can protrude upward and / or downward relative to the support arms 1630. For example, when the ends of the four support arms 1630 are connected to the upper surface of the mass element 1640, the mass element 1640 can protrude downward relative to the support arms 1630. For another example, when the ends of the four support arms 1630 are connected to the lower surface of the mass element 1640, the mass element 1640 can protrude upward relative to the support arms 1630. For another example, when the ends of the four support arms 1630 are connected to the circumferential side wall of the mass element 1640, the mass element 840 can protrude upward and downward relative to the support arms 1630. In some embodiments, the upper surface of the mass element 1640 is on the same horizontal plane as the upper surface of the support arms 1630, and / or the lower surface of the mass element 1640 is on the same horizontal plane as the lower surface of the support arms 1630. In some embodiments, the shape of the support arms 1630 can be an approximately L-shaped structure. As shown, the support arms 1630 can include a first support arm 1631 and a second support arm 1632, one end of the first support arm 1631 being connected to one end of the second support arm 1632, wherein the first support arm 1631 and the second support arm 1632 have a certain angle. In some embodiments, the angle ranges from 75° to 105°. In some embodiments, one end of the first support arm 1631 away from the connection between the first support arm 1631 and the second support arm 1632 is connected to the base structure 1610, and one end of the second support arm 1632 away from the connection between the first support arm 1631 and the second support arm 1632 is connected to the upper surface, the lower surface, or the circumferential side wall of the mass element 1640, so that the mass element 1640 is suspended in the hollow portion of the base structure 1610. Figure 17

[0219] In some embodiments, the acoustic transducing unit is a multi-layer structure, which can include a first electrode layer, a second electrode layer, a piezoelectric layer, an elastic layer, a seed layer, an electrode insulation channel, an electrode insulation channel, and the like. For the layer structure of the acoustic transducing unit, the mass element 1640, and the like, please refer to the description of the acoustic transducing unit in the bone conduction sound transmission device 800. Figure 17 ​The descriptions of the middle acoustic transducing unit 820, the first electrode layer 821, the second electrode layer 823, the piezoelectric layer 822, the vibration unit, the mass element 840, the extension region 8210, the electrode insulation channel 8201, the electrode indentation channel, and the electrode insulation channel 8200 are not repeated here.

[0220] In some embodiments, the bone conduction sound transducing device according to any of the above embodiments can further comprise a limiting structure (not shown in the figures), which is a plate-like structure. In some embodiments, the limiting structure can be located in the hollow part of the base structure, and the limiting structure can be located above or below the laminated structure and arranged opposite to the laminated structure. In some embodiments, when the base structure is a structure that penetrates from top to bottom, the limiting structure can also be located on the top or bottom of the base structure. The limiting structure is arranged apart from the mass unit of the laminated structure, and when a larger impact is received, the limiting structure can limit the amplitude of the mass unit in the laminated structure, avoiding violent vibration and damaging the device. In some embodiments, the limiting structure can be a rigid structure (for example, a limiting block), or a structure with a certain elasticity (for example, an elastic soft pad, a buffer cantilever beam, or a buffer support arm and a limiting block are arranged at the same time, etc.).

[0221] The laminated structure has a natural frequency, and when the frequency of the external vibration signal approaches the natural frequency, the laminated structure will produce a larger amplitude, thereby outputting a larger electrical signal. Therefore, the response of the bone conduction sound transducing device to external vibration will exhibit a resonance peak near the natural frequency. In some embodiments, by changing the parameters of the laminated structure, the natural frequency of the laminated structure can be shifted to the speech frequency range, so that the resonance peak of the bone conduction sound transducing device is located in the speech frequency range, thereby improving the sensitivity of the bone conduction sound transducing device to respond to vibration in the speech frequency range (for example, the frequency range before the resonance peak). As shown in Figure 17 The resonance peak 1701 in the frequency response curve (solid line curve in Figure 18 ) corresponding to the natural frequency of the laminated structure has a smaller frequency than the resonance peak 1702 in the frequency response curve (dotted line curve in Figure 18 ) corresponding to the natural frequency of the laminated structure. For external vibration signals with a frequency less than the frequency of the resonance peak 1701, the bone conduction sound transducing device corresponding to the solid line curve will have higher sensitivity.

[0222] The displacement output formula of the laminated structure is as follows:

[0223]

[0224] where M is the mass of the laminated structure, R is the damping of the laminated structure, K is the elastic coefficient of the laminated structure, F is the driving force amplitude, x aLet ω be the displacement of the laminated structure, ω be the angular frequency of the external force, and ω0 be the natural frequency of the laminated structure. At that time, ωM <Kω -1 If the natural frequency ω0 of the stacked structure is reduced (by increasing M, decreasing K, or both M and K), then |ωM <Kω -1 | Decrease, corresponding displacement output x a Increase. When the excitation frequency ω = ω0, ωM = Kω -1 Changing the natural frequency ω0 of the vibration-to-electrical signal conversion device (layered structure) corresponds to the displacement output x. a Unchanged. When the excitation frequency ω>ω0, ωM>Kω -1 If the natural frequency ω0 of the vibration-to-electrical signal conversion device is reduced (by increasing M or decreasing K, or simultaneously increasing M and decreasing K), then |ωM-Kω -1 |Increase, corresponding displacement output x a Decrease.

[0225] As the resonant peak occurs earlier, a peak value appears in the speech frequency band. Bone conduction devices receive excessive signal in the resonant peak frequency band when picking up signals, resulting in poor call quality. In some embodiments, to improve the quality of the sound signal acquired by the bone conduction device, a damping structure layer can be provided at the laminated structure. This damping structure layer can increase the energy loss of the laminated structure during vibration, especially the loss in the resonant frequency band. Here, the damping coefficient is described using the reciprocal of the mechanical quality factor, 1 / Q:

[0226]

[0227] Q -1 It is the reciprocal of the quality factor, also known as the structural loss factor η, Δf is the frequency difference f1-f2 at half the resonance amplitude (also known as the 3dB bandwidth), and f0 is the resonance frequency.

[0228] The relationship between the loss factor η of the laminated structure and the loss factor tanδ of the damping material is as follows:

[0229]

[0230] Where X is the shear parameter, which is related to the thickness and material properties of each layer in the laminated structure. Y is the stiffness parameter, which is related to the thickness and Young's modulus of each layer in the laminated structure.

[0231] It can be seen from formula (6) and formula (7) that the loss factor η of the laminated structure can be adjusted in a suitable range by adjusting the material of the damping structure layer and the material of each layer of the laminated structure. With the increase of the damping of the damping structure layer of the laminated structure, the mechanical quality factor Q decreases, and the corresponding 3dB bandwidth increases. The damping of the damping structure layer is different under different stress (deformation) states, for example, it presents larger damping under high stress or large amplitude. Therefore, by utilizing the characteristics that the amplitude of the laminated structure is small in the non-resonance region and large in the resonance region, the Q value of the resonance region can be reduced by increasing the damping structure layer while ensuring that the sensitivity of the bone conduction microphone in the non-resonance region is not reduced, so that the frequency response of the bone conduction microphone is relatively flat in the entire frequency range. Figure 1 is a frequency response curve diagram of a bone conduction microphone with and without a damping structure layer according to some embodiments of the present application. As shown in Figure 3 , the frequency response curve 1802 of the electrical signal output by the bone conduction microphone with the damping structure layer is relatively flat compared with the frequency response curve 1801 of the electrical signal output by the bone conduction microphone without the damping structure layer.

[0232] In some embodiments, the bone conduction microphone can include at least one damping structure layer, and the peripheral side of the at least one damping structure layer can be connected with the base structure. In some embodiments, the at least one damping structure layer can be located between the upper surface and / or the lower surface of the laminated structure or the multi-layer laminated structure of the laminated structure. In some embodiments, for the macro-size laminated structure and the base structure, the damping structure layer can be directly bonded to the surface of the base structure or the laminated structure. In some embodiments, for the MEMS device, the damping structure layer can be connected with the laminated structure and the base structure by using semiconductor processes such as evaporation, spin coating, micro-assembly, etc. In some embodiments, the shape of the damping structure layer can be circular, elliptical, triangular, quadrilateral, hexagonal, octagonal, etc. regular or irregular shape. 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 film.

[0233] In order to more clearly describe the damping structure layer, the bone conduction microphone in the form of a cantilever beam (for example, the bone conduction microphone 100 as shown in Figure 4 , the bone conduction microphone 300 as shown in Figure 19 , and the bone conduction microphone 400 as shown in Figure 19 ) is taken as an exemplary illustration. Figure 20 is a cross-sectional view of a bone conduction microphone according to some embodiments of the present application. As shown in Figure 20As shown, the bone conduction sound transmission device 1900 may include a base structure 1910, a laminated structure 1920, and a damping structure layer 1930. Further, one end of the laminated structure 1920 is connected to the upper surface of the base structure 1910, and the other end of the laminated structure 1920 is suspended in the hollow portion of the base structure 1910. The damping structure layer 1930 is located on the upper surface of the laminated structure 1920. The area of ​​the damping structure layer 1930 may be larger than the area of ​​the laminated structure 1920; that is, the damping structure layer 1930 may not only cover the upper surface of the laminated structure 1920 but also further cover the gap between the laminated structure 1920 and the base structure 1910. In some embodiments, at least a portion of the periphery of the damping structure layer 1930 may be fixed to the base structure 1910.

[0234] Figure 21 This is a cross-sectional view of a bone conduction sound transmission device provided according to some embodiments of this application. For example... Figure 21 As shown, the bone conduction sound transmission device 2000 may include a base structure 2010, a laminated structure 2020, and two damping structural layers, wherein the two damping structural layers include a first damping structural layer 2030 and a second damping structural layer 2040. Further, the second damping structural layer 2040 is connected to the upper surface of the base structure 2010, and the lower surface of the laminated structure 2020 is connected to the upper surface of the second damping structural layer 2030. One end of the laminated structure 2020 is suspended in the hollow portion of the base structure 2010, and the first damping structural layer 2030 is located on the upper surface of the laminated structure 2020. The area of ​​the first damping structural layer 2030 and / or the second damping structural layer 2040 is larger than the area of ​​the laminated structure 2020.

[0235] Figures 19-21 This is a cross-sectional view of a bone conduction sound transmission device provided according to some embodiments of this application. For example... Figure 5 As shown, the bone conduction sound transmission device 2100 may include a base structure 2110, a laminated structure 2120, and a damping structure layer 2130. Further, the damping structure layer 2130 is located on the lower surface of the base structure 2110. The lower surface of the laminated structure 2120 is connected to the upper surface of the damping structure layer 2130, and one end of the laminated structure 2120 is suspended in the hollow portion of the base structure 2110.

[0236] It should be noted that the location of the damping structure layer (e.g., damping structure layer 1930) is not limited to the above. Figure 7 The upper and / or lower surfaces of the laminated structure can also be located between the multiple layers of the laminated structure. For example, the damping structure layer can be located between the elastic layer and the first electrode layer. As another example, the damping structure layer can also be located between the first elastic layer and the second elastic layer. Furthermore, the damping structure layer is not limited to the cantilever beam type bone conduction sound transmission device described above, but can also be applied to… Figure 8, Figure 11 , Figure 15 , Figure 16 , ​ and ​ are not described here.

[0237] The foregoing description has been set forth merely to illustrate the basic concepts of the present application. It is not intended to be an exhaustive description of the application and its many alternatives, modifications, and variations. Although the present application has been described in detail with reference to the specific features, it is not intended that the application be limited, to this exact configuration. Those skilled in the art will recognize that various changes can be made to the application without departing from the spirit and scope of the present application. Such changes are also intended to be encompassed by this application.

[0238] Also, the present application has been described using specific language which should not be construed as limiting the application in any way. As used in this specification, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Further, the terms "comprises", "comprising", "includes", "including" and / or "contains", "containing" as used herein, are specifically intended to be open-ended terms i.e., to mean including, but not limited to. Similarly, the terms "comprises", "comprising", "includes", "including" and / or "contains", "containing" as used herein, are specifically intended to be open-ended terms i.e., to mean including, but not limited to. Also, the terms "coupled" and / or "coupling", when used in the present specification, mean the joining of two members directly or indirectly to one another. Such joining can be stationary in nature or movable in nature. The terms "attached" and / or "attaching", when used in the present specification, mean the joining of two members directly or indirectly to one another. Such joining can be stationary in nature or movable in nature. The terms "attached" and / or "attaching", when used in the present specification, mean the joining of two members directly or indirectly to one another. Such joining can be stationary in nature or movable in nature. It is to be further understood that a specific number of configurations of the present application can be described as an example, and that the application can be practiced in other configurations. Furthermore, the terms "a" or "an", as used herein, mean "one or more" when applied to any element. All publications, patents and patent documents cited herein are incorporated by reference herein in their entirety for the purpose of explaining the concepts that are described in the publication, patent or patent document and for the purpose of demonstrating that the publication, patent or patent document as filed constitutes prior art to the present application.

[0239] Moreover, those skilled in the art will appreciate that the application can be practiced with a variety of alternative systems, methods, and materials. The application is not limited to the specific examples described herein. In addition, it is contemplated that various modifications in form, design, implementation, measurement, procedure, materials, and use can be made without departing from the spirit and scope of the application. Accordingly, other implementations are within the scope of the following claims.

[0240] Furthermore, the order of the processing elements and sequences, unless specifically stated to the contrary, are not designed to be a limitation with regard to the present processes and methods. Although the above description has discussed certain embodiments of the application, other alternatives, modifications, and equivalents thereof will become apparent to those skilled in the art in view of the foregoing description. For example, although the system components described above can be implemented through hardware devices, they can also be implemented through software solutions, such as installing the described system on existing processing devices or mobile devices.

[0241] Similarly, it is to be noticed that the term "comprising", used in the description, is not intended to exclude other elements or steps. It is to be understood that the elements or steps recited can also be combined in a plurality of ways with the other elements or steps. It is especially noted that the order of the steps can be changed, and that the use of the term "comprising" does not exclude other elements or steps than those identified as essential.

[0242] Some embodiments use numerical descriptors, quantities of attributes. It is to be understood that such numerical descriptors used in the description of embodiments, in some instances, are modified by the adjectives "about", "approximately", or "substantially". Unless otherwise stated, "about", "approximately", or "substantially" indicates that the described numerical value is permitted to vary by ±20%. Accordingly, in some embodiments, numerical values used in the specification and claims are approximations that can vary depending on the desired characteristics of the individual embodiments. In some embodiments, numerical values should be considered in the context of the number of significant digits and errors inherent to some measurements. Although the numerical ranges and parameters setting forth the broad scope of some embodiments of the application are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values set forth in the specific examples are provided to be as precise as reasonably possible. However, some variations may

[0243] Each patent, patent application, publication, document, article, book, specification, and other material cited in this application is hereby incorporated by reference in its entirety. Nothing herein is to be construed as an admission that the application is not entitled to antedate such material by virtue of prior application. To the extent the material incorporated by reference contradicts or contradicts specifically identified definitions, statements, or figures set forth in this application, including general and specific description, what is in this application controls. In addition, to the extent permitted, the appended claims are intended to cover any and all equivalents of the features described herein.

[0244] Finally, it should be understood that the embodiments described herein are merely exemplary of the principles of the application. Other embodiments can fall within the scope of the application. Thus, although the application has been described with respect to example embodiments, it will be recognized that the scope of the application encompasses alternatives and modifications thereof. Accordingly, the embodiments of the application are not limited to the examples described above, but rather are limited only by the claims.

Claims

1. A bone conduction microphone, wherein, include: A stacked structure formed by vibrating units and acoustic transducers; A base structure is configured to support the laminated structure, at least one side of the laminated structure being physically connected to the base structure; The substrate structure vibrates based on an external vibration signal, and the vibration unit deforms in response to the vibration of the substrate structure; the acoustic transducer generates an electrical signal based on the deformation of the vibration unit; wherein, the resonant frequency of the bone conduction microphone is 2.5kHz-4.5kHz; The base structure includes a hollow frame structure, one end of the laminated structure is connected to the base structure, and the other end of the laminated structure is suspended in the hollow position of the frame structure. The vibration unit includes a support arm and a mass element. The acoustic transducer is stacked with the support arm and completely covers the support arm. The mass element is connected to the substrate structure through the support arm. The acoustic transducer includes a first electrode layer, a piezoelectric layer, and a second electrode layer stacked together. The second electrode layer is connected to the upper or lower surface of the support arm. The first electrode layer is provided with an electrode insulation channel, which divides the first electrode layer into a first part. The first part is connected to or close to the mass element, or the first part is connected to or close to the substrate structure. The first part, the piezoelectric layer corresponding to the first part, and the second electrode layer corresponding to the first part serve as an effective acoustic transducer for generating the electrical signal.

2. The bone conduction microphone according to claim 1, characterized in that, The resonant frequency of the bone conduction microphone is 2.5kHz-3.5kHz.

3. The bone conduction microphone according to claim 1, wherein, The support arm includes at least one elastic layer.

4. The bone conduction microphone according to claim 1, wherein, The acoustic transducer unit further includes a seed layer, which is located between the second electrode layer and the support arm.

5. The bone conduction microphone according to claim 1, wherein, The first portion is connected to or near the mass element, and the electrode insulating channel separates the first electrode layer near the connection between the support arm and the substrate structure into a second portion, which is used to lead out the electrical signal.

6. The bone conduction microphone according to claim 1, wherein, The resonant frequency of the bone conduction microphone is positively correlated with the stiffness of the vibration unit.

7. The bone conduction microphone according to claim 1, wherein, The resonant frequency of the bone conduction microphone is negatively correlated with the mass of the stacked structure.

8. The bone conduction microphone according to claim 1, wherein, The thickness of the first electrode layer is 80nm-250nm.

9. The bone conduction microphone according to claim 1, wherein, The thickness of the piezoelectric layer is 0.8um-5um.

10. The bone conduction microphone according to claim 1, wherein, The thickness of the second electrode layer is 80nm-250nm.

11. The bone conduction microphone according to claim 1, characterized in that, The ratio of the electrical signal strength to the noise strength of the bone conduction microphone is 50%-100% of the maximum ratio of electrical signal strength to noise strength.

12. The bone conduction microphone according to claim 1, wherein, One end of the support arm is connected to the mass element, and the other end of the support arm is connected to the base structure. There are at least two support arms, and the mass element is connected to the base structure through the at least two support arms.

13. The bone conduction microphone according to claim 1, wherein, It also includes a limiting structure located in the hollow portion of the base structure, wherein the limiting structure is connected to the base structure and is located above and / or below the mass element.

14. The bone conduction microphone according to any one of claims 1-13, wherein, It also includes at least one damping layer, which covers the upper surface, lower surface and / or interior of the laminated structure.

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