Bone conduction sound transmission device

Abstract

The application discloses a bone conduction sound transmission device, 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; and the acoustic transducing unit generates an electric signal based on the deformation of the vibration unit.

Description

[0001] Cross-referencing

[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 sound transmission device technology, and in particular to a bone conduction sound transmission device. Background Technology

[0004] A microphone receives external vibration signals, converts them into electrical signals using an acoustic transducer, and outputs 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 output. Therefore, it is necessary to provide a bone conduction microphone device 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 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.

[0008] In some embodiments, the vibration unit includes at least one elastic layer, and the acoustic transducer includes at least a first electrode layer, a piezoelectric layer, and a second electrode layer arranged sequentially 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.

[0009] In some embodiments, the acoustic transducing unit further comprises a seed layer, which is located on the lower surface of the second electrode layer.

[0010] 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 stack structure, wherein the first electrode layer, the piezoelectric layer and / or the second electrode layer are close to the junction of the stack structure and the base structure.

[0011] 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.

[0012] 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 and the second comb-shaped structure cooperate to form the electrode layer, and the electrode layer is located on the upper surface or the lower surface of the piezoelectric layer.

[0013] In some embodiments, the first comb-shaped structure and the second comb-shaped structure extend along the length direction of the stack structure.

[0014] 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.

[0015] In some embodiments, the suspension membrane structure comprises a plurality of holes, which are distributed along the circumferential direction of the acoustic transducing unit.

[0016] In some embodiments, the radial distance from the edge of the acoustic transducing unit to the center of the plurality of holes is 100-400 μm.

[0017] In some embodiments, the acoustic transducing unit is in a ring structure, and the thickness of the suspension membrane structure in the inner side region of the ring structure is greater than that in the outer side region of the ring structure.

[0018] In some embodiments, the acoustic transducing unit is in a ring structure, and the density of the suspension membrane structure in the inner side region of the ring structure is greater than that in the outer side region of the ring structure.

[0019] In some embodiments, the vibration unit further comprises a mass element, which is located on the upper surface or the lower surface of the suspension membrane structure.

[0020] In some embodiments, the acoustic transducing unit and the mass element are located on different sides of the suspension membrane structure, respectively.

[0021] In some embodiments, the acoustic transducing unit and the mass element are located on the same side of the suspension membrane structure, wherein the acoustic transducing unit is a ring structure, and the ring structure is distributed along the circumference of the mass element.

[0022] In some embodiments, the vibration unit comprises at least one support arm and a mass element, and the mass element is connected to the base structure through the at least one support arm.

[0023] 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.

[0024] 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 to the upper surface or lower surface of the at least one support arm.

[0025] 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.

[0026] 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.

[0027] In some embodiments, the area of the first electrode layer is not greater than the area of the piezoelectric layer, and the entire region of the first electrode layer is located on the surface of the piezoelectric layer.

[0028] In some embodiments, the first electrode layer, the piezoelectric layer and the second electrode layer of the acoustic transducing unit are close to the connection between the mass element or / and the support arm and the base structure.

[0029] 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.

[0030] In some embodiments, a limiting structure is further included, and the limiting structure is located in the hollow part of the base structure, wherein the limiting structure is connected to the base structure, and the limiting structure is located above and / or below the mass element.

[0031] In some embodiments, the bone conduction sound transmission device of any of the preceding items further comprises at least one damping layer covering the upper surface, the lower surface and / or the interior of the laminated structure.

[0032] In some embodiments, the bone conduction sound transmission device has a resonance frequency of 1 kHz-5 kHz.

[0033] In some embodiments, the bone conduction sound transmission device has a resonance frequency of 2.5 kHz-4.5 kHz.

[0034] In some embodiments, the bone conduction sound transmission device has a resonance frequency of 2.5 kHz-3.5 kHz.

[0035] In some embodiments, the resonance frequency of the bone conduction sound transmission device is positively correlated with the stiffness of the vibration unit.

[0036] In some embodiments, the resonance frequency of the bone conduction sound transmission device is negatively correlated with the mass of the laminated structure.

[0037] In some embodiments, the vibration unit comprises at least one support arm and a mass element, the mass element being connected to the base structure through the at least one support arm.

[0038] In some embodiments, the acoustic transduction unit is located on the upper surface, the lower surface or the interior of the at least one support arm.

[0039] In some embodiments, the acoustic transduction unit comprises a first electrode layer, a first piezoelectric layer and a second electrode layer arranged in order from top to bottom, the first electrode layer or the second electrode layer being connected to the upper surface or the lower surface of the at least one support arm.

[0040] In some embodiments, the mass element is located on the upper surface or the lower surface of the first electrode layer or the second electrode layer.

[0041] In some embodiments, the area of the first electrode layer, the first 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 first piezoelectric layer and / or the second electrode layer covers the upper surface or the lower surface of the at least one support arm.

[0042] In some embodiments, the area of the first electrode layer is not greater than the area of the first piezoelectric layer, and the entire area of the first electrode layer is located on the surface of the first piezoelectric layer.

[0043] In some embodiments, the first electrode layer, the first piezoelectric layer, the second electrode layer of the acoustic transducing unit are located at one end of the connection between the support arm and the mass element and / or one end of the connection between the support arm and the base structure.

[0044] In some embodiments, the acoustic transducing unit comprises at least one elastic layer, which is located on the upper surface and / or lower surface of the first electrode layer or the second electrode layer.

[0045] In some embodiments, the acoustic transducing unit further comprises a first seed layer, which is arranged between the elastic layer and the first electrode layer or between the elastic layer and the second electrode layer.

[0046] In some embodiments, the acoustic transducing unit further comprises at least one wire electrode layer, which is arranged on the base structure, and is used to lead out an electrical signal from the base structure.

[0047] In some embodiments, the elastic layer is arranged between the support arm and the first electrode layer, and the first seed layer is arranged between the elastic layer and the first electrode layer; or the elastic layer is arranged between the support arm and the second electrode layer, and the first seed layer is arranged between the elastic layer and the second electrode layer.

[0048] In some embodiments, a neutral layer is formed on the bone conduction sound device, and the deformation stress of the neutral layer is zero when the support arm deforms; the neutral layer does not coincide with the first piezoelectric layer in the thickness direction.

[0049] In some embodiments, the thickness of the first electrode layer is 80 nm-250 nm, and / or the thickness of the second electrode layer is 80 nm-250 nm.

[0050] In some embodiments, the thickness of the first piezoelectric layer is 0.8 μm-2 μm.

[0051] In some embodiments, the thickness of the elastic layer is 0.5 μm-10 μm.

[0052] In some embodiments, the thickness of the first seed layer is 10 nm-120 nm.

[0053] In some embodiments, the thickness of the elastic layer is 1-6 times the thickness of the first piezoelectric layer.

[0054] In some embodiments, the thickness of the mass element is 3001 μm-400 μm.

[0055] In some embodiments, the mass element comprises, from bottom to top, a substrate layer, a third electrode layer, a second piezoelectric layer, and a fourth electrode layer.

[0056] In some embodiments, the mass element further comprises a second seed layer disposed between the substrate layer and the third electrode layer.

[0057] In some embodiments, the substrate layer has a thickness of 20-400 μm.

[0058] In some embodiments, the ratio of the intensity of the electrical signal of the bone conduction sound receiving device to the intensity of the noise is 50-100% of the maximum ratio of the intensity of the electrical signal to the intensity of the noise.

[0059] In some embodiments, the acoustic transducing unit comprises a first electrode layer, a first piezoelectric layer, and a second electrode layer, and the ratio of the intensity of the electrical signal of the bone conduction sound receiving device to the intensity of the noise is negatively correlated with the thickness of the first piezoelectric layer.

[0060] In some embodiments, the acoustic transducing unit comprises a first electrode layer, a first piezoelectric layer, and a second electrode layer, and the ratio of the intensity of the electrical signal of the bone conduction sound receiving device to the intensity of the noise is negatively correlated with the area of the overlapping region of the first electrode layer, the piezoelectric layer, and the second electrode layer.

[0061] In some embodiments, the acoustic transducing unit comprises a first electrode layer, a first piezoelectric layer, and a second electrode layer, and the ratio of the area of the overlapping region of the first electrode layer, the first piezoelectric layer, and the second electrode layer to the area of the cross section of the support arm perpendicular to the thickness direction is 5-40%.

[0062] In some embodiments, the first electrode layer or the second electrode layer is provided with an electrode insulation channel for separating the first electrode layer or the second electrode layer into two or more electrode regions.

[0063] In some embodiments, the width of the electrode insulation channel is less than or equal to 20 μm.

[0064] In some embodiments, the first electrode layer or the second electrode layer has an electrode lead for connecting the electrode region to the base structure.

[0065] In some embodiments, the width of the electrode lead is less than or equal to 20 μm.

[0066] In some embodiments, the overlapping region of the first electrode layer, the first piezoelectric layer, and the second electrode layer extends toward the mass element to form an extended region, the extended region being on the upper surface or the lower surface of the mass element.

[0067] In some embodiments, the width of the extended region in a plane perpendicular to the thickness direction is 1.2 to 2 times the width of the connecting portion of the support arm and the mass element in a plane perpendicular to the thickness direction.

[0068] In some embodiments, the number of support arms is two or more, and the two or more support arms are disposed around the mass element.

[0069] In some embodiments, the cross section of the at least one support arm perpendicular to the thickness direction is polygonal.

[0070] In some embodiments, the side length of the polygon is 100 to 600 μm.

[0071] In some embodiments, the cross section of the at least one support arm perpendicular to the thickness direction is rectangular or trapezoidal.

[0072] In some embodiments, the cross section of the mass element perpendicular to the thickness direction is polygonal, and the number of support arms corresponds to the number of sides of the polygon.

[0073] In some embodiments, when the cross section of the support arm perpendicular to the thickness direction is rectangular, the length of the support arm is 100 to 500 μm, and the width of the support arm is 150 to 400 μm.

[0074] In some embodiments, when the cross section of the support arm perpendicular to the thickness direction is trapezoidal, the height of the trapezoid is 150 to 600 μm, the length of the long side of the trapezoid is 300 to 600 μm, and the length of the short side of the trapezoid is 100 to 400 μm.

[0075] In some embodiments, the support arm includes a first strip-shaped portion and a second strip-shaped portion, one end of the first strip-shaped portion is connected to the mass element, the other end of the first strip-shaped portion is connected to one end of the second strip-shaped portion, and the other end of the second strip-shaped portion is connected to the base structure.

[0076] In some embodiments, the length of the first strip-shaped portion is 20 to 200 μm, and the length-width of the first strip-shaped portion is 50 to 400 μm.

[0077] In some embodiments, the length of the second strip-shaped portion is 500 to 1300 μm, and the length of the second strip-shaped portion is 50 to 400 μm.

[0078] In some embodiments, when the connection between the first strip-shaped portion and the mass element is located at the end of the side edge of the mass element; the width of the first strip-shaped portion is 50 μm-300 μm, and the length of the first strip-shaped portion is 20 μm-200 μm.

[0079] In some embodiments, when the connection between the first strip-shaped portion and the mass element is located at the end of the side edge of the mass element; the width of the second strip-shaped portion is 50 μm-300 μm; and the length of the second strip-shaped portion is 800 μm-1300 μm.

[0080] In some embodiments, when the connection between the first strip-shaped portion and the mass element is located at the midpoint of the side edge of the mass element; the width of the first strip-shaped portion is 100 μm-400 μm; and the length of the first strip-shaped portion is 20 μm-200 μm.

[0081] In some embodiments, when the connection between the first strip-shaped portion and the mass element is located at the midpoint of the side edge of the mass element; the width of the second strip-shaped portion is 100 μm-400 μm; and the length of the second strip-shaped portion is 500 μm-1000 μm.

[0082] In some embodiments, the cross section of the mass element perpendicular to the thickness direction is rectangular, and the first strip-shaped portion and the second strip-shaped portion are perpendicular.

[0083] In some embodiments, the support arm comprises a first strip-shaped portion, a second strip-shaped portion, and a third strip-shaped portion; one end of the first strip-shaped portion is connected to the mass element, and the other end of the first strip-shaped portion is connected to one end of the second strip-shaped portion; the other end of the second strip-shaped portion is connected to one end of the third strip-shaped portion; and the other end of the third strip-shaped portion is connected to the base structure.

[0084] In some embodiments, the length of the first strip-shaped portion is 20 μm-200 μm; and the length-width of the first strip-shaped portion is 50 μm-300 μm.

[0085] In some embodiments, the length of the second strip-shaped portion is 500 μm-1200 μm; and the length of the second strip-shaped portion is 50 μm-300 μm.

[0086] In some embodiments, the length of the third strip-shaped portion is 800 μm-1300 μm; and the width of the third strip-shaped portion is 50 μm-300 μm.

[0087] In some embodiments, the base structure comprises a frame structure body with a hollow inner cavity; and the support arm and the mass element are both arranged in the inner cavity of the frame structure body.

[0088] In some embodiments, the shape of the mass element corresponds to the shape of the inner cavity.

[0089] In some embodiments, the thickness of the support arm and the thickness of the acoustic transducing unit are less than the thickness of the mass element.

[0090] In some embodiments, the thickness of the support arm and the thickness of the acoustic transducing unit are greater than or equal to the thickness of the mass element.

[0091] In some embodiments, the bone conduction sound device further comprises a limiting structure, the limiting structure is located in the inner cavity 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. BRIEF DESCRIPTION OF DRAWINGS

[0092] The present application will be further illustrated in the manner 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:

[0093] Figure 1 is a structural schematic diagram of a bone conduction sound device according to some embodiments of the present application;

[0094] Figure 2 is a cross-sectional view of the bone conduction sound device A-A shown in the figure; Figure 1

[0095] Figure 3 is a structural schematic diagram of another bone conduction sound device according to some embodiments of the present application;

[0096] Figure 4 is a structural schematic diagram of a bone conduction sound device according to some other embodiments of the present application;

[0097] Figure 5 is a structural schematic diagram of a bone conduction sound device according to some embodiments of the present application;

[0098] Figure 6 is a cross-sectional view of the local structure of the bone conduction sound device shown in the figure; Figure 5

[0099] Figure 7 is a structural schematic diagram of a bone conduction sound device according to some embodiments of the present application;

[0100] Figure 8 is a structural schematic diagram of a bone conduction sound device according to some embodiments of the present application;

[0101] ​​Figure 9 is a front view of a bone conduction sound transmission device according to Figure 8 ;

[0102] Figure 10 is a cross-sectional view of the bone conduction sound transmission device C-C according to Figure 9 ;

[0103] Figure 11 is a front view of a bone conduction sound transmission device in a vibration state according to Figure 8 ;

[0104] Figure 12 is a cross-sectional view of the bone conduction sound transmission device D-D according to Figure 11 ;

[0105] Figure 13 is a structural schematic diagram of a bone conduction sound transmission device according to Figure 8 ;

[0106] Figure 14 is another structural schematic diagram of a bone conduction sound transmission device according to Figure 8 ;

[0107] Figure 15 is still another structural schematic diagram of a bone conduction sound transmission device according to Figure 8 ;

[0108] Figure 16 is yet another structural schematic diagram of a bone conduction sound transmission device according to Figure 8 ;

[0109] Figure 17 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0110] Figure 18 is a cross-sectional view of the bone conduction sound transmission device E-E according to Figure 17 ;

[0111] Figure 19 is a structural schematic diagram of a bone conduction sound transmission device according to Figure 17 ;

[0112] Figure 20 is another structural schematic diagram of a bone conduction sound transmission device according to Figure 17 ;

[0113] Figure 21 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0114] Figure 22 is a structural schematic diagram of a bone conduction sound transmission device according to Figure 21 ;

[0115] Figure 23 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0116] Figure 24 is a front view of a bone conduction sound transmission device according to Figure 23

[0117] Figure 25 is a cross-sectional view of the bone conduction sound transmission device F-F according to Figure 24

[0118] Figure 26 is a structural schematic diagram of a bone conduction sound transmission device according to Figure 23

[0119] Figure 27 is another structural schematic diagram of a bone conduction sound transmission device according to Figure 23

[0120] Figure 28 is still another structural schematic diagram of a bone conduction sound transmission device according to Figure 23

[0121] Figure 29 is yet another structural schematic diagram of a bone conduction sound transmission device according to Figure 23

[0122] Figure 30 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0123] Figure 31 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0124] Figure 32 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application;

[0125] Figure 33 is another structural schematic diagram of a bone conduction sound transmission device according to Figure 32

[0126] Figure 34 is a frequency response curve of a laminated structure inherent frequency advance according to some embodiments of the present application;

[0127] Figure 35 is a frequency response curve diagram of a bone conduction sound transmission device with or without damping structure layer according to some embodiments of the present application;

[0128] Figure 36 is a cross-sectional view of a bone conduction sound transmission device according to some embodiments of the present application; ​​​​​​​

[0129] Figure 37 is a cross-sectional view of a bone conduction microphone device according to some embodiments of the present application;

[0130] Figure 38 is a cross-sectional view of a bone conduction microphone device according to some embodiments of the present application. DETAILED DESCRIPTION

[0131] 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 be applied to other similar scenarios without creative labor on the basis of these drawings. Unless it is obvious from the language context or otherwise stated, the same reference numbers in the drawings represent the same structures or operations. 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.

[0132] It should be understood that, for the convenience of description of the present application, the positional relationship indicated by the terms "center", "upper surface", "lower surface", "upper", "lower", "top", "bottom", "inner", "outer", "axial", "radial", "periphery", "exterior", and the like is based on the positional relationship shown in the drawings, and does not indicate that the device, component, or unit referred to must have a particular positional relationship, and should not be understood as a limitation on the present application.

[0133] It should be understood that the "system", "device", "unit", and / or "module" used herein is a method for distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

[0134] 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 speaking, 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.

[0135] 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. On the contrary, 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.

[0136] 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.

[0137] The vibration unit refers to a part of the laminated structure that is prone to deformation under the action of external force or inertial force. The vibration unit can be used to transmit the deformation caused by the action of external force or inertial force to the acoustic transducing unit. In some embodiments, the vibration unit and the acoustic transducing unit overlap to form the 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 electric signal based on the deformation of the elastic layer. The first electrode layer and the second electrode layer can collect the electric 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 electric 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 electric signal.

[0138] 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, PZT thin film material) made by a deposition process (e.g., magnetron sputtering deposition process, chemical vapor deposition process, etc.). 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, 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 can refer to a piezoelectric polycrystal obtained 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), barium lithium niobate lead (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.

[0139] 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 on 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, and further, when the vibration unit is deformed, the piezoelectric layer of the acoustic transducing unit generates a potential difference (voltage) under the deformation stress of the vibration unit. 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 so as 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 of a human body when speaking 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.

[0140] The bone conduction sound receiving device receives external vibration signals, and converts the vibration signals into electrical signals by using a laminated structure (including an acoustic transducing unit and a vibration unit). The electrical signals are output after being processed by a rear-end circuit. Resonance can also be referred to as "sympathetic vibration". When the frequency of an external vibration signal is the same as or very close to the natural oscillation frequency of a system, the amplitude of the vibration increases sharply, which is called resonance. The frequency at which resonance occurs is called "resonant frequency". The bone conduction sound receiving device has a natural frequency. When the frequency of an 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 vibrations will exhibit 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 2.5 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 speech frequency range of 1 kHz-5 kHz. In some embodiments, the resonant frequency of the bone conduction sound receiving device is 2 kHz-5 kHz. In some embodiments, the resonant frequency of the bone conduction sound receiving device is 2.5 kHz-4.9 kHz. In some embodiments, the resonant frequency of the bone conduction sound receiving device can be adjusted to the speech frequency range of 1 kHz-4.5 kHz. In some embodiments, the resonant frequency of the bone conduction sound receiving device can be adjusted to the speech frequency range of 2.5 kHz-4.5 kHz. In some embodiments, the resonant frequency of the bone conduction sound receiving device can be adjusted to the speech frequency range of 2.5 kHz-3.5 kHz. 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 speech frequency range of 1 kHz-5 kHz, thereby improving the sensitivity of the bone conduction sound receiving device to respond to vibrations in the speech frequency range (for example, the frequency range before the resonance peak, i.e., 20 Hz-5 kHz).

[0141] In some embodiments, the resonant frequency of the bone conduction sound receiving device is 3.5 kHz-4.7 kHz. In some embodiments, the resonant frequency of the bone conduction sound receiving device is 4 kHz-4.5 kHz.

[0142] 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 is working, 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), and 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. Among them, the equivalent stiffness is the stiffness after the bone conduction sound transmission device is equivalent to the mass-spring-damper system model, and the equivalent mass is the mass after the bone conduction sound transmission device is equivalent to the mass-spring-damper system model. Therefore, adjusting the resonance frequency (or natural frequency) of the bone conduction sound transmission device, that is, adjusting the equivalent stiffness and the equivalent mass of the vibration unit or the laminated structure.

[0143] 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 is working, 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:

[0144]

[0145] 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 ， ζ is the system equivalent relative damping coefficient (damping ratio).

[0146] 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 ζ of the system is mainly affected by the equivalent stiffness and the equivalent mass. For example, the resonance frequency f0of the piezoelectric bone conduction sound transmission device can be expressed as: Figure 8The support arm 830 of the bone conduction sound transmission device shown provides spring and damping effects for the vibration system, and the mass element 840 provides mass effect. Therefore, the support arm 830 mainly affects the equivalent stiffness k of the system, while also affecting the equivalent mass m of the system, and the mass element 840 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 resonance frequency f0 of the bone conduction sound transmission device by theory. By establishing a model of the corresponding structure and parameters, the frequency response of the bone conduction sound transmission device can be solved by using a finite element simulation tool. In some embodiments, the resonance 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 resonance 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 film, and the structure of the suspension film plus the mass element. In some embodiments, the resonance 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, the mass element, the cantilever beam, the suspension film, etc.

[0147] 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 speech frequency range. 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.

[0148] Figure 1 is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of the present application. Figure 2 is Figure 1 is a cross-sectional view of the bone conduction sound transmission device shown.

[0149] As shown in Figure 1 and Figure 2 The bone conduction sound transmission 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 hollow, 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 hollow part of the frame structure body. It should be noted that the frame structure body is not limited to Figure 1The frame structure can be a rectangular parallelepiped as shown in the figure, and 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 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 of the base structure 110 where the hollow portion is located. In some embodiments, the side wall of the base structure 110 where the hollow portion 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 Figure 1 the connecting seat 140 is fixedly connected to the surface fixed end 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 at the side wall of the base structure 110 where the hollow portion is located. For example, the side wall of the base structure 110 where the hollow portion 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, etc. 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.

[0150] 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 part of the laminated structure that can elastically deform, and the acoustic transduction unit 120 refers to the part 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 Figure 1The 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, PZT thin film material) made by a deposition process (e.g., a magnetron sputtering deposition process, a chemical vapor deposition process, etc.). 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, boracite, 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 material of the piezoelectric layer 122 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.

[0151] 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 receiving device 100, 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 receiving 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 receiving 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 receiving device 100 on the basis of improving the sensitivity of the bone conduction sound receiving 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 receiving 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.

[0152] In some embodiments, in order to increase the output electrical signal and improve the signal-to-noise ratio of the bone conduction sound device 100, 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 100 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 transduction 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).

[0153] 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.

[0154] 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 facing 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.

[0155] It should be noted that the shape of the stacked structure is not limited to Figure 1 the rectangular shape 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 semicircle, etc., which will not be further limited here. 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 110, 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 110.

[0156] 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 basically the same as the bone conduction sound transducing device 100 shown in Figure 1 The biggest difference between the bone conduction sound transducing device 300 and the bone conduction sound transducing device 100 shown in Figure 3 is 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. For details of the first electrode layer 321, the piezoelectric layer 322 and the second electrode layer 323 of the acoustic transducing unit 320, and the first elastic layer 331 and the second elastic layer 332 of the vibration unit 330, etc., please refer to Figure 1The contents of each layer of the acoustic transducer 120 and the vibration unit 130 are described below. Additionally, other components in the acoustic transducer 120 and the vibration unit 130 (e.g., the seed layer) are also applicable. Figure 3 The bone conduction sound transmission device 300 shown here will not be described in detail.

[0157] Figure 4 This is a structural schematic diagram of a bone conduction sound transmission device according to other embodiments of this application. For example... Figure 4 As shown, the bone conduction sound transmission device 400 may include a base structure 410 and a laminated structure, wherein at least a portion of the laminated structure is connected to the base structure 410. In some embodiments, the base structure 410 may be a hollow frame structure, and a portion of the laminated structure (e.g., the end of the laminated structure away from the connection between the base structure 410 and the laminated structure) may be located in the hollow portion of the frame structure. It should be noted that the frame structure is not limited to... Figure 4 The cuboid shape shown can be, in some embodiments, a regular or irregular structure such as a frustum or 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 to or in contact with the frame structure, allowing the free end of the laminated structure to 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, lower surface, or sidewall of the hollow portion of the base structure 410. In some embodiments, the sidewall of the hollow portion of the base structure 410 can also be provided with a mounting groove adapted to the fixed end of the laminated structure, allowing the fixed end of the laminated structure to connect with the base structure 410. Here, "connection" can be understood as fixing the laminated structure and the base structure 410 together by welding, riveting, snap-fitting, bolting, or other methods after they have been fabricated separately. In some embodiments, during the fabrication process, the stacked structure can also be deposited on the substrate structure 410 by physical deposition (e.g., physical vapor deposition) or chemical deposition (e.g., chemical vapor deposition). In some embodiments, one or more stacked structures can be disposed on the substrate structure 410; for example, the number of stacked structures can be 1, 2, 3, 7, etc. Further, the multiple stacked structures can be evenly distributed equidistantly along the circumference of the substrate structure 410, or they can be unevenly distributed.

[0158] 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 includes 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 made of piezoelectric ceramic material. When the piezoelectric layer 423 is made of piezoelectric ceramic material, the polarization direction of the piezoelectric layer 423 is consistent with the length direction of the cantilever beam, utilizing the piezoelectric constant d of the piezoelectric ceramic. 33 This characteristic greatly enhances the output signal and improves sensitivity. The piezoelectric constant d... 33 This refers to the proportionality constant of how the piezoelectric layer 323 converts mechanical energy into electrical energy. It is important to note that... Figure 4 The piezoelectric layer 423 shown can also be made of other materials. When the polarization direction of the piezoelectric layer 423 made of other materials is consistent with the thickness direction of the cantilever beam, the acoustic transducer unit 420 can be replaced by... Figure 1 The acoustic transducer unit 120 shown.

[0159] 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 receiving device 400, 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 receiving 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 receiving 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 receiving device 400 on the basis of improving the sensitivity of the bone conduction sound receiving 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 receiving 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 entirely or partially covers the surface of the vibration unit 430, and the area of the piezoelectric layer 423 can be not greater than the area of the electrode layer. Preferably, the area of the piezoelectric layer 423 covering the vibration unit 430 is not greater than 1 / 2 of the area of the electrode layer. Preferably, the area of the piezoelectric layer 423 covering the vibration unit 430 is not greater than 1 / 3 of the area of the piezoelectric layer 423. Further preferably, the area of the piezoelectric layer 423 covering 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 device 400.

[0160] In some embodiments, in order to increase the output electric signal and improve the signal-to-noise ratio of the bone conduction sound device 400, 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 device 400.

[0161] In some embodiments, in order to increase the output electric signal and improve the signal-to-noise ratio of the bone conduction sound device 400, 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 device 400.

[0162] Figure 5 is a structural schematic diagram of a bone conduction sound device according to some embodiments of the present application; Figure 6 is Figure 5 is a cross-sectional view of a partial structure of the bone conduction sound device shown in Figure 5 and Figure 6 As shown in Figure 5 , the bone conduction sound device 500 can include a base structure 510 and a laminated structure, wherein at least part of the laminated structure is connected to the base structure 510. In some embodiments, the base structure 510 can be a hollow frame structure, 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

[0163] In some embodiments, the laminated structure can include an acoustic transduction unit 520 and a vibration unit. In some embodiments, the vibration unit can be arranged on the upper surface or lower surface of the acoustic transduction unit 520. As shown in Figure 5As shown, the vibration unit includes a suspended membrane structure 530 fixed on the base structure 510 by connecting the peripheral side of the suspended membrane structure 530 with the base structure 510, and the central region of the suspended membrane structure 530 is suspended in the hollow portion of the base structure 510. In some embodiments, the suspended membrane structure 530 can be located on the upper surface or the lower surface of the base structure 510. In some embodiments, the peripheral side of the suspended membrane structure 530 can also be connected with the inner wall of the hollow portion of the base structure 510. Here, the "connection" can be understood as, after the suspended membrane structure 530 and the base structure 510 are respectively prepared, the suspended membrane structure 530 is fixed on the upper surface, the lower surface of the base structure 510, or the side wall of the hollow portion of the base structure 510 by a mechanical fixing method (for example, a strong bonding method, a riveting method, a clamping method, an inlaying method, etc.), or in the preparation process, the suspended membrane structure 530 is deposited on the base structure 510 by a physical deposition method (for example, a physical vapor deposition method) or a chemical deposition method (for example, a chemical vapor deposition method). In some embodiments, the suspended membrane structure 530 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, etc. In some embodiments, the shape of the suspended membrane structure 530 can be a circle, an ellipse, a triangle, a quadrilateral, a pentagon, a hexagon, etc. polygon, or any other arbitrary shape.

[0164] In some embodiments, the acoustic transducing unit 520 can be located on the upper surface or the lower surface of the suspension membrane structure 530. In some embodiments, the suspension membrane structure 530 can include a plurality of holes 5300 distributed around the center of the acoustic transducing unit 520 along the circumference of the acoustic transducing unit 520. It can be understood that by providing a plurality of holes 5300 on the suspension membrane structure 530, the stiffness of the suspension membrane structure 530 at different positions can be adjusted, so that the stiffness of the suspension membrane structure 530 at the region near the plurality of holes 5300 is reduced, and the stiffness of the suspension membrane structure 530 far from the plurality of holes 5300 is relatively large. When the suspension membrane structure 530 moves relative to the base structure 510, the deformation of the suspension membrane structure 530 at the region near the plurality of holes 5300 is larger, and the deformation of the suspension membrane structure 530 far from the plurality of holes 5300 is smaller. At this time, placing the acoustic transducing unit 520 on the region near the plurality of holes 5300 of the suspension membrane structure 530 can be more conducive to the acoustic transducing unit 520 to collect vibration signals, thereby effectively improving the sensitivity of the bone conduction sound transmission device 500, and the structure of each component in the bone conduction sound transmission device 500 is relatively simple, which is convenient for production or assembly. In some embodiments, the holes 5300 on the suspension membrane structure 530 can be circular holes, elliptical holes, square holes, other polygonal holes, or any other shape. In some embodiments, the resonant frequency (so that the resonant frequency is 2kHz-5kHz) and stress distribution of the bone conduction sound transmission device 500 can be adjusted by changing the size, number, interval distance, and position of the plurality of holes 5300, so as 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. The range of the resonant frequency can be adaptively adjusted according to different application scenarios, which is not limited further herein.

[0165] in combination with 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 a piezoelectric effect under the deformation stress of the vibration unit (e.g., the diaphragm 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 522 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, boron, tourmaline, red zinc, 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 a 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, such as polyvinylidene fluoride (PVDF). In some embodiments, the first electrode layer 521 and the second electrode layer 523 adopt 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 material can include RuO2, MnO2, PbO2, NiO, etc., or any combination thereof.

[0166] As Figure 5As shown, in some embodiments, the plurality of holes 5300 enclose a circular region, in order to improve the sound pressure output effect of the acoustic transducing unit 520, the acoustic transducing unit 520 can be arranged on the suspension membrane structure 530 in a region close to the plurality of holes 5300, further, the acoustic transducing unit 520 can be in a ring structure, and is distributed along the inner side of the circular region enclosed by the plurality of holes 5300. In some embodiments, the acoustic transducing unit 520 in a ring structure can also be distributed along the outer side of the circular region enclosed by the plurality of holes 5300. In some embodiments, the piezoelectric layer 522 of the acoustic transducing unit 520 can be a piezoelectric ring, and the first electrode layer 521 and the second electrode layer 523 on the upper and lower surfaces of the piezoelectric ring can be electrode rings. In some embodiments, a lead structure 5200 is further arranged on the acoustic transducing unit 520, and the lead structure 5200 is used to transmit the electrical signal collected by the electrode rings (e.g., the first electrode layer 521 and the second electrode layer 523) to the subsequent circuit. In some embodiments, in order to improve the output electrical signal of the bone conduction sound transmission device 500, the radial distance from the edge of the acoustic transducing unit 520 (e.g., the ring structure) to the center of each hole 5300 can be 100 μm-400 μm. Preferably, the radial distance from the edge of the acoustic transducing unit 520 (e.g., the ring structure) to the center of each hole 5300 can be 150 μm-300 μm. Further preferably, the radial distance from the edge of the acoustic transducing unit 520 (e.g., the ring structure) to the center of each hole 5300 can be 150 μm-250 μm.

[0167] In some embodiments, the output electrical signal of the bone conduction sound transmission device 500 can also be improved by adjusting the shape, size (e.g., length, width, thickness), and material of the lead structure 5200.

[0168] In some alternative embodiments, the deformation stress of the suspension membrane structure 530 at different positions can also be changed by adjusting the thickness or density of different regions of the suspension membrane structure 530. For example only, in some embodiments, the acoustic transducing unit 520 is arranged in a ring structure, and the thickness of the suspension membrane structure 530 in the region inside the ring structure is greater than the thickness of the region outside the ring structure. In other embodiments, the density of the suspension membrane structure 530 in the region inside the ring structure is greater than the density of the region outside the ring structure. By changing the density or thickness of the suspension membrane structure 530 at different positions, the suspension membrane mass in the region inside the ring structure is greater than the suspension membrane mass in the region outside the ring structure, and when the suspension membrane structure 530 and the base structure 510 move relative to each other, the deformation of the suspension membrane structure 530 near the ring structure of the acoustic transducing unit 520 is greater, and the deformation stress generated is also greater, thereby improving the output electrical signal of the bone conduction sound transmission device 500.

[0169] It should be noted that the shape of the area enclosed by the multiple holes 5300 is not limited to... Figure 5 The circle shown can also be a semicircle, a quarter circle, an ellipse, a semi-ellipse, a triangle, a rectangle, or other regular or irregular shapes. The shape of the acoustic transducer unit 520 can be adaptively adjusted according to the shape of the area enclosed by the multiple holes 5300. For example, when the area enclosed by the multiple holes 5300 is rectangular, the acoustic transducer unit 520 can be rectangular, and the rectangular acoustic transducer units 520 can be distributed along the inner or outer side of the rectangle enclosed by the multiple holes 5300. As another example, when the area enclosed by the multiple holes 5300 is semicircular, the acoustic transducer unit 520 can be semi-annular, and the semi-annular acoustic transducer units 520 can be distributed along the inner or outer side of the rectangle enclosed by the multiple holes 5300. In some embodiments, Figure 5 The suspended membrane structure 530 can be without openings.

[0170] Figure 7 This is a structural schematic diagram of a bone conduction sound transmission device according to some embodiments of this application. Figure 7 The bone conduction sound transmission device 700 shown is... Figure 5 The bone conduction sound transmission devices 500 shown are largely the same in structure, with the difference being... Figure 7 The vibration unit of the bone conduction sound transmission device 700 shown includes a diaphragm structure 730 and a mass element 740.

[0171] like Figure 7 As shown, the bone conduction sound transmission device 700 may include a base structure 710 and a laminated structure, wherein at least a portion of the laminated structure is connected to the base structure 710. In some embodiments, the base structure 710 may be a hollow frame structure, and a portion of the laminated structure may be located in the hollow portion of the frame structure. It should be noted that the frame structure is not limited to... Figure 7 The cuboid shape shown can be, in some embodiments, a regular or irregular structure such as a frustum or cylinder.

[0172] In some embodiments, the stacked structure may include an acoustic transducer unit 720 and a vibration unit. In some embodiments, the vibration unit may be disposed on the upper or lower surface of the acoustic transducer unit 720. Figure 7As shown, the vibration unit includes a suspension membrane structure 730 and a mass element 740, which can be located on the upper surface or lower surface of the suspension membrane structure 730. In some embodiments, the suspension membrane structure 730 can be located on the upper surface or lower surface of the base structure 710. In some embodiments, the peripheral side of the suspension membrane structure 730 can also be connected to the inner wall of the hollow portion of the base structure 710. Here, "connection" can be understood as, after the suspension membrane structure 730 and the base structure 710 are respectively prepared, the suspension membrane structure 730 is fixed to the upper surface, lower surface or side wall of the hollow portion of the base structure 710 by mechanical fixation (for example, strong bonding, riveting, clamping, inlaying, etc.); or in the preparation process, the suspension membrane structure 730 is deposited on the base structure 710 by physical deposition (for example, physical vapor deposition) or chemical deposition (for example, chemical vapor deposition). When the vibration unit moves relative to the base structure 710, the mass element 740 and the self-weight of the suspension membrane structure 730 are different, and the deformation degree of the area where the mass element 740 is located or the area near the mass element 740 on the suspension membrane structure 730 is greater than the deformation degree of the area away from the mass element 740 on the suspension membrane structure 730. In order to improve the output sound pressure of the bone conduction sound device 700, the acoustic transduction unit 720 can be distributed along the circumference of the mass element 740. In some embodiments, the shape of the acoustic transduction unit 720 can be the same as or different from the shape of the mass element 740. Preferably, the shape of the acoustic transduction unit 720 can be the same as the shape of the mass element 740, so that each position of the acoustic transduction unit 720 can be close to the mass element 740, thereby further improving the output electric signal of the bone conduction sound device 700. For example, the mass element 740 is a cylindrical structure, and the acoustic transduction unit 720 can be a ring structure, and the inner diameter of the ring-shaped acoustic transduction unit 720 is greater than the radius of the mass element 740, so that the acoustic transduction unit 720 is arranged along the circumference of the mass element 740. In some embodiments, the acoustic transduction unit 720 can include a first electrode layer and a second electrode layer and a piezoelectric layer located between the two electrode layers, and the first electrode layer, the piezoelectric layer and the second electrode layer are combined into a structure body adapted to the shape of the mass element 740. For example, the mass element 740 is a cylindrical structure, and the acoustic transduction unit 720 can be a ring structure, at this time, the first electrode layer, the piezoelectric layer and the second electrode layer are all ring structures, and are sequentially arranged and combined into a ring structure from top to bottom.

[0173] 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 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 on the suspension membrane structure 730 can be within the area of the acoustic transducing unit 720.

[0174] In some embodiments, the output electrical signal of the bone conduction sound transducing device 700 can be improved by changing the size, shape, position of the mass element 740, and the position, shape, size of the piezoelectric layer. In some embodiments, the sound pressure output effect of the bone conduction sound transducing device 700 can also be improved by changing the shape, material, size of the suspension membrane structure 730. Here, the first electrode layer, the second electrode layer and the piezoelectric layer 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 Figure 5 , the suspension membrane structure 730 is similar to the suspension membrane structure 530, and the lead structure 7200 is similar to the lead structure 5200, and thus no further description is given here.

[0175] Figure 8 is a structural schematic diagram of a bone conduction sound transducing device according to some embodiments of the present application; Figure 9 is a structural schematic diagram of a bone conduction sound transducing device according to some embodiments of the present application; Figure 8 is a plan view of a bone conduction sound transducing device according to some embodiments of the present application; Figure 10 is a plan view of a bone conduction sound transducing device according to some embodiments of the present application; Figure 9 is a sectional view of the bone conduction sound transducing device at C-C according to some embodiments of the present application. As shown in Figure 8-10 , the vibration unit includes at least one support arm 830 and a mass element 840, and the mass element 840 is connected to the base structure 810 through the at least one support arm 830. The number of the support arms 830 can be one, two, four, six, etc. In some embodiments, the base structure 810 and the support arm 830, and the mass element 840 and the support arm 830 can be connected by welding, bonding, etc. In some embodiments, the base structure 810 and the support arm 830 can be processed on the same base material (such as the substrate of a silicon wafer) by micro-nano processing technology. Alternatively, the base structure 810, the support arm 830 and the mass element 840 can be processed on the same base material (such as the substrate of a silicon wafer) by micro-nano processing technology. In some embodiments, the acoustic transducing unit 820 can be located on the upper surface, the lower surface or the inside of the at least one support arm 830.

[0176] As shown in Figure 8As shown, the base structure 810 is a cuboid frame structure. In some embodiments, the interior of the base structure 810 may include a hollow portion (such as...). Figure 10 The hollow cavity 811 shown is used to house the acoustic transducer 820 and the vibration unit. In some embodiments, the base structure 810 may include a frame structure with a hollow cavity 811, with a support arm 830 and a mass element 840 both disposed within the cavity 811. One end of the support arm 830 is connected to the base structure 810, and the other end is connected to the mass element 840. In some embodiments, the hollow portion (such as the hollow cavity 811) is perpendicular to the thickness direction (…). Figure 10 The shape of the cross-section (in the direction indicated by the middle arrow) can be circular, quadrilateral (e.g., rectangle, parallelogram), pentagon, hexagon, heptagon, octagon, or other regular or irregular shapes. In some embodiments, the side length of the hollow portion with a rectangular cross-section perpendicular to the thickness direction can be 0.8mm-2mm. In some embodiments, the side length can be 1mm-1.5mm. In some embodiments, the shape of the hollow inner cavity 811 of the substrate structure 810 can correspond to the shape of the mass element 840. For example, when the cross-sectional shape of the inner cavity 811 perpendicular to the thickness direction is rectangular, the cross-sectional shape of the mass element 840 perpendicular to the thickness direction is also rectangular.

[0177] In some embodiments, the number of support arms 830 is two or more, and the two or more support arms 830 are arranged around the mass element 840. For example, the number of support arms 830 can be two, three, four, six, seven, etc. In some embodiments, the cross-section of the mass element 840 perpendicular to the thickness direction is a polygon, and the number of support arms 830 corresponds to the number of sides of the polygon. For example, the number of support arms 830 can be equal to the number of sides of the polygon. Another example is that the number of support arms 830 can be a multiple of the number of sides of the polygon, such as two, three, five, etc. As an example only, when the cross-section of the mass element 840 perpendicular to the thickness direction is a quadrilateral, the number of support arms 830 is four. The four support arms 830 can be connected to the four sides of the quadrilateral, respectively. Alternatively, when the cross-section of the mass element 840 perpendicular to the thickness direction is a quadrilateral, the number of support arms 830 is eight. In this case, every two support arms 830 are connected to one of the four sides of the quadrilateral. This arrangement allows for a more uniform force distribution between the support arm 830 and the mass element 840. In some embodiments, the connection points between each support arm 830 and the mass element 840 can be arranged rotationally symmetrically about the center of the mass element 840, thereby ensuring a more uniform force distribution between the support arm 830 and the mass element 840.

[0178] In some embodiments, the vibration unit may include four support arms 830 and a mass element 840. One end of each support arm 830 is connected to the upper surface, lower surface, or sidewall of the hollow portion of the base structure 810, and the other end of each support arm 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 sidewall 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 upper surface of the mass element 840 and the upper surface of the support arm 830 are substantially on the same horizontal plane. In other embodiments, the lower surface of the mass element 840 and the lower surface of the support arm 830 are substantially on the same horizontal plane. In still other embodiments, both the upper and lower surfaces of the mass element 840 and the support arm 830 are substantially on the same horizontal plane. In some embodiments, the support arm 830 is rectangular in shape, meaning that the cross-section of the support arm 830 perpendicular to the thickness direction is rectangular. One opposite side of the rectangle is connected to the mass element 840, and the other opposite side is connected to the base structure 810.

[0179] In some embodiments, such as Figure 9 As shown, the length X of the support arm 830 is 100 μm to 500 μm. In some embodiments, the length X of the support arm 830 is 150 μm to 350 μm. In some embodiments, the width Y of the support arm 830 is 150 μm to 400 μm. In some embodiments, the width Y of the support arm 830 is 250 μm to 350 μm. By designing and adjusting the dimensions of the support arm 830, the stiffness of the support arm 830 can be adjusted, thereby adjusting the resonant frequency of the bone conduction sound transmission device 800.

[0180] Furthermore, the bone conduction sound transmission device 800 may include an acoustic transducer unit 820. For example... Figure 10As shown, the acoustic transducing unit 820 can include a first electrode layer 821, a first 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 with the upper surface or the lower surface of the support arm 830 (e.g., the elastic layer 824). For example, the upper surface of the first electrode layer 821 can be connected with the lower surface of the support arm 830, or the lower surface of the second electrode layer 823 can be connected with the upper surface of the support arm 830. The first piezoelectric layer 822 can generate a voltage (a 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 (an electrical signal) out. In order to make the resonance frequency of the bone conduction sound transmission device 800 in a specific frequency range (e.g., 2000Hz-5000Hz), the materials and thicknesses of the acoustic transducing unit 820 (e.g., the first electrode layer 821, the second electrode layer 823 and the first piezoelectric layer 822), the vibration unit (e.g., the support arm 830) can be adjusted to achieve this.

[0181] In some embodiments, the thickness of the first electrode layer 821 can be 80nm-250nm. In some embodiments, the thickness of the first electrode layer 821 is 100nm-150nm. In some embodiments, the thickness of the second electrode layer 823 can be 80nm-250nm. In some embodiments, the thickness of the second electrode layer 823 is 100nm-200nm. In some embodiments, the thickness of the first piezoelectric layer 822 can be 0.8μm-2μm. In some embodiments, the thickness of the first piezoelectric layer 822 is 0.8μm-1.5μm. By designing and adjusting the thicknesses of the first electrode layer 821, the first piezoelectric layer 822 and the second electrode layer 823, the magnitude of the deformation stress that the first piezoelectric layer 822 receives during the vibration of the bone conduction sound transmission device 800 can be adjusted, so that the first piezoelectric layer 822 can receive a larger deformation stress, thereby making the acoustic transducing unit 820 generate a larger electrical signal.

[0182] In some embodiments, the material of the first electrode layer 821 and the second electrode layer 823 can be one or more of the commonly used metal materials in semiconductors, such as Mo, Cu, Al, Ti, Au, etc. In some embodiments, the material of the first piezoelectric layer 822 can be aluminum nitride (AIN), lead zirconate titanate piezoelectric ceramic (PZT), polyvinylidene fluoride (PVDF), zinc oxide (ZnO), etc. In some embodiments, the structure of the bone conduction sound transmission device 800 can be fabricated on a substrate material (such as a silicon wafer) according to the required functions of the bone conduction sound transmission device 800 using micro-nano processing technology. For example, the second electrode layer 823 can be prepared on the substrate material by electron beam evaporation or physical vapor deposition (PVD) such as magnetron sputtering method, etc. Then, the first piezoelectric layer 822 can be prepared on the second electrode layer 823 by electron beam evaporation or physical vapor deposition (PVD) such as magnetron sputtering method, etc. Finally, the first electrode layer 821 can be prepared on the first piezoelectric layer 822 again by electron beam evaporation or physical vapor deposition (PVD) such as magnetron sputtering method, etc. In some embodiments, an etching stop layer can be prepared on the substrate material (for example, before the second electrode layer 823 is prepared), which can facilitate the accurate control of the size of the electrode layer (such as the first electrode layer or the second electrode layer), and can also prevent the subsequent etching process from damaging the substrate material. Specifically, the etching stop layer can be prepared on the substrate material by chemical vapor deposition (CVD) or thermal oxidation method, etc. The thickness of the etching stop layer can be 100 nm-2 μm, and in some embodiments, the thickness of the etching stop layer can be 300 nm-1 μm.

[0183] In some embodiments, the area of the first electrode layer 821, the first piezoelectric layer 822 and / or the second electrode layer 823 is not greater than the area of the support arm 830, and part or all of the first electrode layer 821, the first piezoelectric layer 822 and / or the second electrode layer 823 covers the upper surface or the lower surface of at least one support arm 830. In some embodiments, when the first piezoelectric layer 822 is located between the first electrode layer 821 and the support arm 830 (for example, the first electrode layer 821 and the first piezoelectric layer 822 are arranged from top to bottom on the upper surface of the support arm, or the first electrode layer 821 and the first piezoelectric layer 822 are arranged from bottom to top on the lower surface of the support arm), the area of the first electrode layer 821 is not greater than the area of the first piezoelectric layer 822, and the entire area of the first electrode layer 821 is located on the surface of the first piezoelectric layer 822. In other embodiments, the area of the first electrode layer 821 can be equal to the area of the first piezoelectric layer 822.

[0184] In some embodiments, the first electrode layer 821, the first piezoelectric layer 822, and the second electrode layer 823 of the acoustic transducing unit 820 are located at the end where the mass element 840 and the support arm 830 are connected. In other embodiments, the first electrode layer 821, the first piezoelectric layer 822, and the second electrode layer 823 of the acoustic transducing unit 820 are located at the end where the support arm 830 and the base structure 810 are connected. In yet other embodiments, the first electrode layer 821, the first piezoelectric layer 822, and the second electrode layer 823 of the acoustic transducing unit 820 are located at the end where the mass element 840 and the support arm 830 are connected, and the first electrode layer 821, the first piezoelectric layer 822, and the second electrode layer 823 of the acoustic transducing unit 820 are also located at the end where the support arm 830 and the base structure 810 are connected. The end where the mass element 840 and the support arm 830 are connected and the end where the support arm 830 and the base structure 810 are connected have large deformation stress during the vibration of the vibration unit, and thus the first electrode layer 821, the first piezoelectric layer 822, and the second electrode layer 823 of the acoustic transducing unit 820 are arranged in these two areas to generate a large electrical signal.

[0185] In some embodiments, the mass element 840 can be located on the upper surface or the lower surface of the first electrode layer 821 or the second electrode layer 823. For example, the mass element 840 can be located on the upper surface of the first electrode layer 821, or the mass element 840 can be located on the lower surface of the second electrode layer 823. In other embodiments, the upper surface of the mass element 840 can be flush or substantially flush with the upper surface of the first electrode layer 821. In yet other embodiments, the lower surface of the mass element 840 can be flush or substantially flush with the lower surface of the second electrode layer 823. In still other embodiments, the upper surface of the mass element 840 can be flush or substantially flush with the upper surface of the first electrode layer 821, and the lower surface of the mass element 840 can be flush or substantially flush with the lower surface of the second electrode layer 823.

[0186] In some embodiments, as shown in FIG. 8A, the first electrode layer 821, the first piezoelectric layer 822, and the second electrode layer 823 of the acoustic transducing unit 820 are located at the end where the mass element 840 and the support arm 830 are connected. In other embodiments, as shown in FIG. 8B, the first electrode layer 821, the first piezoelectric layer 822, and the second electrode layer 823 of the acoustic transducing unit 820 are located at the end where the support arm 830 and the base structure 810 are connected. In yet other embodiments, as shown in FIG. 8C, the first electrode layer 821, the first piezoelectric layer 822, and the second electrode layer 823 of the acoustic transducing unit 820 are located at the end where the mass element 840 and the support arm 830 are connected, and the first electrode layer 821, the first piezoelectric layer 822, and the second electrode layer 823 of the acoustic transducing unit 820 are also located at the end where the support arm 830 and the base structure 810 are connected. Figure 10As shown, the acoustic transducing unit 820 can include at least one elastic layer 824. The at least one elastic layer 824 can be located on the upper surface and / or lower surface of the first electrode layer 821 or the second electrode layer 823. For example, the at least one elastic layer 824 can be located on the upper surface of the first electrode layer 821, or the elastic layer 824 can be located on the lower surface of the second electrode layer 823. In some embodiments, when the support arm 830 is a plurality of elastic layers 824, the acoustic transducing unit 820 can also be located between the plurality of elastic layers 824. The elastic layer 824 can be deformed during vibration, the first piezoelectric layer 822 can generate an electrical signal based on the deformation of the elastic layer 824, and the first electrode layer 821 and the second electrode layer 823 can collect the electrical signal. In some embodiments, the thickness of the elastic layer 824 can be 0.5-10 μm. In some embodiments, the thickness of the elastic layer 824 is 2-6 μm. By designing and adjusting the thickness of the elastic layer 824, the magnitude of the deformation stress experienced by the first piezoelectric layer 822 during vibration of the bone conduction sound transmission device 800 can be adjusted.

[0187] In some embodiments, the thickness of the elastic layer 824 is 1-6 times the thickness of the first piezoelectric layer 822. In some preferred embodiments, the thickness of the elastic layer 824 is 1-3 times the thickness of the first piezoelectric layer 822. By such a thickness setting, the first piezoelectric layer 822 can be moved away from the neutral layer 831, and the magnitude of the deformation stress experienced by the first piezoelectric layer 822 can be increased.

[0188] In some embodiments, the elastic layer 824 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, when the acoustic transducing unit includes two or more elastic layers 824, the materials of different elastic layers 824 can be the same or different. In some embodiments, the elastic layer 824 can be a single-layer structure (e.g., a layer structure made of a single material). The material of the single-layer structure can include, but is not limited to, silicon (Si), silicon dioxide (SiO2), silicon nitride (SiNx), or silicon carbide (SiC), etc. In some embodiments, the elastic layer 824 can also include a multi-layer structure (e.g., a multi-layer structure composed of multiple materials, each layer structure can be made of a single material). For example, the multi-layer structure can be made of a combination of silicon and silicon dioxide, a combination of silicon and silicon nitride, etc. In some embodiments, one or more elastic layers 824 can be prepared on the etching barrier layer or the base material by chemical vapor deposition (CVD) or physical vapor deposition (PVD) method, etc.

[0189] In some embodiments, the acoustic transducing unit 820 can further include a wire bonding electrode layer 826 (PAD layer), which can be located on the first electrode layer 821 and the second electrode layer 823, and which can be used to connect the first electrode layer 821 and the second electrode layer 823 to an external circuit through external wire bonding (e.g., gold wire, aluminum wire, etc.), so as to lead out 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 wire bonding electrode layer 826 can include copper foil, titanium, copper, etc. In some embodiments, the thickness of the wire bonding electrode layer 826 can be 100-200 nm. In some embodiments, the thickness of the wire bonding electrode layer 826 can be 150-200 nm. By designing and adjusting the thickness of the wire bonding electrode layer 826, the magnitude of the deformation stress that the first piezoelectric layer 822 receives during the vibration of the bone conduction sound transducing device 800 can be adjusted.

[0190] In some embodiments, the wire bonding electrode layer 826 is provided on the base structure 810. For example, the wire bonding electrode layer 826 can be provided on the upper surface or the lower surface of the base structure 810. The wire bonding electrode layer 826 can be used to lead out the electrical signal from the base structure 810. In some embodiments, the electrical signal can be led from the first electrode layer 821 or the second electrode layer 823 to the base structure 810 by the electrode lead 860 described below. The wire bonding electrode layer 826 can be prepared by a metal lift-off process (LIFT-OFF process) or a deposition-then-etching process, etc. The wire bonding electrode layer 826 can be prepared after the first electrode layer 821, the first piezoelectric layer 822, and the second electrode layer 823 are all prepared.

[0191] In some embodiments, the acoustic transducing unit 820 can further include a first seed layer 825. In some embodiments, the first seed layer 825 can be located between the second electrode layer 823 and the support arm 830. In some embodiments, the first seed layer 825 can be located between the elastic layer 824 and the first electrode layer 821 or between the elastic layer 824 and the second electrode layer 823. In some embodiments, the material of the first seed layer 825 can be the same as the material of the first piezoelectric layer 822. For example, when the material of the first piezoelectric layer 822 is AlN, the material of the first seed layer 825 is also AlN. In some embodiments, the material of the first seed layer 825 can also be different from the material of the first piezoelectric layer 822. It should be noted that the specific frequency range of the resonance frequency of the bone conduction sound transducing device 800 described above is not limited to 2000Hz-5000Hz, but can also be 4000Hz-5000Hz, or 2300Hz-3300Hz, 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 first seed layer 825 can be located between the mass element 840 and the support arm 830. In some embodiments, the thickness of the first seed layer 825 can be 10-120nm. In some embodiments, the thickness of the first seed layer 825 is 40-80nm. By designing and adjusting the thickness of the first seed layer 825, the magnitude of the deformation stress of the first piezoelectric layer 822 during the vibration of the bone conduction sound transducing device 800 can be adjusted.

[0192] By setting the first seed layer 825, a good growth surface structure can be provided for other layers. For example, the elastic layer 824 can be difficult to stably adhere to the electrode layer (the first electrode layer 821 or the second electrode layer 823), and therefore, the first seed layer 825 can be first adhered to the electrode layer (the first electrode layer 821 or the second electrode layer 823), and then the elastic layer 824 is adhered to the first seed layer 825 to achieve stable connection between the layers. In some embodiments, the first seed layer 825 can be prepared on the upper surface of the elastic layer 824. The first seed layer 825 can be prepared by chemical vapor deposition (CVD) or physical vapor deposition (PVD) method, etc.

[0193] In some embodiments, the elastic layer 824 can be arranged between the support arm 830 and the first electrode layer 821, and the first seed layer 825 can be arranged between the elastic layer 824 and the first electrode layer 821. Alternatively, the elastic layer 824 can be arranged between the support arm 830 and the second electrode layer 823, and the first seed layer 825 can be arranged between the elastic layer 824 and the second electrode layer 823. For example, when the acoustic transducing unit 820 is arranged on the upper surface of the support arm 830, the elastic layer 824, the first seed layer 825, the second electrode layer 823, the first piezoelectric layer 822, and the first electrode layer 821 are sequentially arranged from bottom to top. Alternatively, when the acoustic transducing unit 820 is arranged on the lower surface of the support arm 830, the elastic layer 824, the first seed layer 825, the first electrode layer 821, the first piezoelectric layer 822, and the second electrode layer 823 are sequentially arranged from top to bottom. Through such arrangement, a larger electrical signal can be generated, and the connection between the layers of the acoustic transducing unit 820 is stable.

[0194] Figure 11 is a front view of a bone conduction sound transmission device according to Figure 8 is a cross-sectional view of the bone conduction sound transmission device D-D according to Figure 12 is a front view of a bone conduction sound transmission device according to Figure 11 is a cross-sectional view of the bone conduction sound transmission device D-D according to Figure 11 and Figure 12 As shown in FIGS. 8 and 9, the vibration unit (e.g., the support arm 830) of the bone conduction sound transmission device 800 has a neutral layer 831 when it is strained, and the neutral layer 831 has zero deformation stress when the support arm 830 is deformed. That is, the neutral layer 831 is a position layer of the support arm 830 that has zero deformation stress when it is deformed. The output of the piezoelectric material (i.e., the first piezoelectric layer 822) is related to the size of the stress, and the thickness of each layer in the thickness direction affects the stress distribution of each layer under the same vibration signal. Since the neutral layer 831 is a position layer with zero deformation stress, the closer to the neutral layer 831 in the thickness direction, the smaller the deformation stress during the deformation of the support arm 830.

[0195] Based on the foregoing, in the embodiments provided in the present application, the thickness design and connection sequence design of the elastic layer 824 and other layers are performed so that the first piezoelectric layer 822 and the neutral layer 831 do not coincide, thereby ensuring that the first piezoelectric layer 822 can be subjected to deformation stress, and further enabling the first piezoelectric layer 822 to interact with the first electrode layer 821 and / or the second electrode layer 823 to generate an electrical signal. Further, through the thickness design of each layer in the embodiments, the first piezoelectric layer 822 can be made as far away from the neutral layer 831 as possible, so that the deformation stress received by the first piezoelectric layer 822 is as large as possible, thereby making the output electrical signal as large as possible, and further making the sensitivity of the device as large as possible.

[0196] 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 material corresponding to each layer of structure, and the parameters can be the same as or different from those of the elastic layer 824 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 circle, a semicircle, an ellipse, a triangle, a quadrilateral, a pentagon, a hexagon, a heptagon, an octagon, 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 acoustic transducing unit 820, which will not be repeated here. In addition, the materials and parameters of each layer of structure of the acoustic transducing unit 820 can also be applied to the mass element 840. Figure 1 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 7 .

[0197] In some embodiments, the mass element 840 includes a third electrode layer, a second piezoelectric layer, and a fourth electrode layer arranged in sequence from bottom to top. The material, function, and manufacturing method of the third electrode layer can be similar to those of the first electrode layer 821, the material, function, and manufacturing method of the second piezoelectric layer can be similar to those of the first piezoelectric layer 822, and the material, function, and manufacturing method of the fourth electrode layer can be similar to those of the second electrode layer 823, which will not be repeated here. In some embodiments, the mass element 840 can further include a substrate layer. The substrate layer carries the third electrode layer, the second piezoelectric layer, and the fourth electrode layer, and can increase the weight of the mass element 840 and improve the inertia of the mass element 840, thereby improving the sensitivity of the bone conduction sound transmission device 800. In some embodiments, the mass element 840 further includes a second seed layer arranged between the substrate layer and the third electrode layer. The material, function, and manufacturing method of the second seed layer are similar to those of the first seed layer 825, which will not be repeated here. In some embodiments, the thickness of the substrate layer is 20 μm-400 μm. In some embodiments, the thickness of the substrate layer can be 300 μm-400 μm. In some embodiments, the thickness of the substrate layer can be 200 μm-300 μm.

[0198] In some embodiments, the shape of the mass element 840 in the cross section perpendicular to the thickness direction is a quadrilateral. In some embodiments, the shape of the mass element 840 in the cross section perpendicular to the thickness direction is a rectangle. In some embodiments, the length of at least one side of the rectangle can be 600 μm-1200 μm. In some embodiments, the length of at least one side of the rectangle can be 750 μm-1050 μm.

[0199] In some embodiments, the acoustic transducing unit 820 on the mass element 840 and the support arm 830 can be fabricated on different substrate materials (e.g., different silicon wafers), or on the same substrate material. When the acoustic transducing unit 820 on the mass element 840 and the support arm 830 are fabricated on different substrate materials, the mass element 840 can be fabricated on the substrate material by photolithography, etching, or the like. Then, the silicon substrate material with the mass element 840 fabricated thereon can be wafer-bonded to the substrate material with the support arm 830 and the base structure 810 fabricated thereon. In some embodiments, the bonding region can be the region of the mass element 840. In other embodiments, the bonding region can include the region of the mass element 840 and a portion of the base structure 810. In some embodiments, the area of the bonding region on the base structure 810 can account for 10-90% of the area of the cross-section of the base structure 810 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 840 fabricated thereon, except for the mass element 840. In other embodiments, the mass element 840 can be further fabricated on the substrate material with the support arm 830 fabricated thereon. Specifically, a uniform coating and photolithography development process can be performed on the other side (the opposite side of the support arm 830) of the substrate material with the support arm 830 fabricated thereon, 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 840.

[0200] In some embodiments, the acoustic transducing unit 820 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 effective acoustic transducing unit can include the overlapping area of the first electrode layer 821, the first piezoelectric layer 822, and the second electrode layer 823. For example, the first electrode layer 821, the first piezoelectric layer 822, and the second electrode layer 823 have the same shape and area and partially cover the support arm 830 (or the elastic layer 824), and the first electrode layer 821, the first piezoelectric layer 822, and the second electrode layer 823 are effective transducing units. For another example, the first electrode layer 821 and the first 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, the first piezoelectric layer 822, and the part of the second electrode layer 823 corresponding to the first electrode layer 821 form the effective acoustic transducing unit. For another example, the first electrode layer 821 partially covers the support arm 830, and the first piezoelectric layer 822 and the second electrode layer 823 fully cover the support arm 830, and the first electrode layer 821, the part of the first piezoelectric layer 822 corresponding to the first electrode layer 821, and the part of the second electrode layer 823 corresponding to the first electrode layer 821 form the effective acoustic transducing unit. For another example, the first electrode layer 821, the first 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 setting an insulating channel (for example, the electrode insulating channel 850), and the independent electrode part of the first electrode layer 821 from which the electrical signal is led out and the part of the first piezoelectric layer 822 and the second electrode layer 823 corresponding to the first electrode layer 821 are effective transducing units. The independent electrode area of the first electrode layer 821 from which the electrical signal is not led out and the area of the first piezoelectric layer 822 and the second electrode layer 823 corresponding to the independent electrode and the insulating channel of the first electrode layer 821 do not provide electrical signals and mainly provide mechanical effects. 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 of the support arm 830 close to the mass element 840 or close to the connection between the support arm 830 and the base structure 810. In some embodiments, the effective acoustic transducing unit is arranged at the position of the support arm 830 close to the mass element 840. In some embodiments, when the effective acoustic transducing unit is arranged at the position of the support arm 830 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 (the area of the cross section of the support arm 830 perpendicular to the thickness direction) is 5%-40%. In some embodiments, 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 (the area of the cross section of the support arm 830 perpendicular to the thickness direction) is 25%-40%.Further in some embodiments, the ratio of the area of the effective acoustic transducing unit to the area of the support arm 830 (the area of the cross section of the support arm 830 perpendicular to the thickness direction) at the support arm 830 is 30%-35%.

[0201] SIGNAL-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 electrical signal strength 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 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 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 of the bone conduction sound transmission device, and is negatively correlated with the noise floor v of the bone conduction sound transmission device. In some embodiments, the signal-to-noise ratio SNR of the bone conduction sound transmission device can be calculated according to the following formula (1):

[0202]

[0203] wherein v s is the sensitivity of the bone conduction sound transmission device. v s is the noise floor of the bone conduction sound transmission device. In some embodiments, the sensitivity v s of the bone conduction sound transmission device can be calculated by means of finite element numerical calculation method after establishing a model. In some embodiments, the noise floor v ntrms of the bone conduction sound transmission device can be determined by the amplifier circuit (ASIC) noise floor value v ntrms and the transducer (acoustic transducing unit) noise floor value v narms , etc. The noise floor v nsrms of the bone conduction sound transmission device is positively correlated with the amplifier circuit (ASIC) noise floor value v ntrms and the transducer noise floor value v narms . The amplifier circuit (ASIC) noise floor value v nsrms can be calculated during the design of the amplifier circuit or obtained from the manufacturer. In some embodiments, the noise floor v narms of the bone conduction sound transmission device can be calculated according to the following formula (2):ntrms may be related to Boltzmann constant κ B , Fahrenheit temperature T, electrostatic force constant k, dielectric loss tan δ of the piezoelectric layer (e.g., the first piezoelectric layer 822), dielectric constant ε r of the piezoelectric layer (e.g., the first piezoelectric layer 822), thickness d of the piezoelectric layer (e.g., the first piezoelectric layer 822), area S of the effective acoustic transduction unit of the bone conduction sound device, low frequency cutoff frequency f0 of the background noise of the bone conduction sound device, high frequency cutoff frequency f1 of the background noise of the bone conduction sound device, etc.

[0204] In some embodiments, the background noise v ntrms of the bone conduction sound device can be positively related to Boltzmann constant κ B , Fahrenheit temperature T, electrostatic force constant k, dielectric constant ε r of the piezoelectric layer (e.g., the first piezoelectric layer 822), thickness d of the piezoelectric layer (e.g., the first piezoelectric layer 822), and high frequency cutoff frequency f1 of the background noise of the bone conduction sound device. The background noise v ntrms of the bone conduction sound device can be negatively related to area S of the effective acoustic transduction unit of the bone conduction sound device, low frequency cutoff frequency f0 of the background noise of the bone conduction sound device, and dielectric loss tan δ of the piezoelectric layer (e.g., the first piezoelectric layer 822). In some embodiments, the background noise v ntrms of the bone conduction sound device can be calculated by the following formula (2):

[0205] v ntrms = f(v nsrms ,v narms ) = f(κ B ,T,k,tan δ,ε r ,d,S,f1,f0,v narms ,ASIC gain) (2)

[0206] 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. κ B is the Boltzmann constant, T is the Fahrenheit temperature, k is the electrostatic force constant, tan δ is the dielectric loss of the piezoelectric layer (e.g., the first piezoelectric layer 822), ε r is the dielectric constant of the piezoelectric layer (e.g., the first piezoelectric layer 822), d is the thickness of the piezoelectric layer (e.g., the first piezoelectric layer 822), S is the area of the effective acoustic transduction unit of the bone conduction sound device, f0 is the low frequency cutoff frequency of the background noise of the bone conduction sound device, and f1 is the high frequency cutoff frequency of the background noise of the bone conduction sound device.

[0207] Substituting formula (2) into formula (1) can obtain formula (3) for determining the signal-to-noise ratio SNR of the bone conduction sound device:

[0208] The meanings of the parameters in equation (3) are explained above. In equation (3), the dielectric loss tan δ of the piezoelectric material, the dielectric constant ε of the piezoelectric material, the thickness of the piezoelectric layer (e.g., the first piezoelectric layer 822), the material of the piezoelectric layer (e.g., the first piezoelectric layer 822), the sensitivity (the sensitivity is affected by the material and structure of the bone conduction sound transducing device), and the like are related to the signal-to-noise ratio. r The material of the piezoelectric layer (e.g., the first piezoelectric layer 822) is related to the material of the piezoelectric layer (e.g., the first piezoelectric layer 822). As can be seen from equation (3) above, 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 822), the material of the piezoelectric layer (e.g., the first piezoelectric layer 822), the sensitivity (the sensitivity is affected by the material and structure of the bone conduction sound transducing device), and the like.

[0209] According to the signal-to-noise ratio (SNR) solving formula of the bone conduction sound transducing device proposed in this patent, the materials of the electrode layer (the first electrode layer 821 and the second electrode layer 823), the piezoelectric layer (the first piezoelectric layer 822 and the second piezoelectric layer), the elastic layer 824, and the mass element 840 are designed, and the structure of the bone conduction sound transducing device is designed, so that the design scheme can meet the range requirement of the resonant frequency f0 while the signal-to-noise ratio (SNR) of the bone conduction sound transducing device is maximized. For example, the structure of the support arm plus the mass element (or the structure of the cantilever beam, the structure of the punched suspension film, the structure of the suspension film plus the mass element, etc.), and the size of different components of the bone conduction sound transducing device are designed, such as the length, width, thickness of the support arm 830, the mass element 840, and the area of the effective acoustic transducing unit. For example, in the structure of the support arm plus the mass element, the stiffness of the support arm 830 and the mass of the mass element 840 can be adjusted by designing the materials, sizes, etc. of the parts of the acoustic transducing unit 820, the support arm 830, and the mass element 840, so that stress concentration occurs at the support arm 830. The stress concentration at the support arm 830 can increase the output electric signal of the bone conduction sound transducing device, thereby maximizing the output sensitivity and signal-to-noise ratio of the bone conduction sound transducing device. In the above design process, in order to ensure that the designed bone conduction sound transducing device has good reliability, the signal-to-noise ratio SNR can be adjusted by adjusting the materials, structures, and sizes of different components, so that the SNR is less than the maximized SNR, for example, the designed SNR is 80%-100% of the maximized SNR; the designed SNR is 50%-100% of the maximized SNR; the designed SNR is 20%-100% of the maximized SNR.

[0210] The smaller the coverage area of ​​the effective acoustic transducer unit at the support arm 830, the greater the intensity of the generated electrical signal. However, a smaller area of ​​the effective acoustic transducer unit leads to a smaller capacitance, resulting in increased noise in the final output. By setting the ratio of the coverage area of ​​the effective acoustic transducer unit at the support arm 830 to the area of ​​the support arm 830 (the area of ​​the cross-section of the support arm 830 perpendicular to the thickness direction) to the aforementioned ratio (e.g., 25%-40%), the generated electrical signal of the effective acoustic transducer unit can be made strong while the noise is low, thus improving the sound transmission effect of the bone conduction sound transmission device 800.

[0211] 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 laminated structure moves relative to the base structure 810, the deformation stress at the connection points between the support arm 830 and the mass element 840, and between the support arm 830 and the base structure 810, is greater than the deformation stress in the middle region of the support arm 830. Correspondingly, the strength of the output voltage at the connection points between the support arm 830 and the mass element 840, and between the support arm 830 and the base structure 810, is also greater than the strength of the output voltage in the middle region of the support arm 830. In some embodiments, such as Figure 13 and Figure 14 As shown, when the acoustic transducer 820 completely or nearly completely covers the upper or lower surface of the support arm 830, in order to improve the signal-to-noise ratio of the bone conduction sound transmission device 800, an electrode insulating channel 850 can be provided on the first electrode layer 821. The electrode insulating channel 850 divides the first electrode layer 821 into two (or more) parts, such 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 substrate structure 810. The part of the first electrode layer 821 and its corresponding first piezoelectric layer 822 and second electrode layer 823 separated by the electrode insulating channel 850 that leads out electrical signals is the effective acoustic transducer. In some embodiments, the electrode insulating channel 850 can be a straight line extending along the width direction of the support arm 830. In some embodiments, the width of the electrode insulating channel 850 can be less than 20 μm. In some embodiments, the width of the electrode insulating channel 850 can be 2 μm-20 μm. In some embodiments, the width of the electrode insulating channel 850 can be 4μm-10μm.

[0212] In some embodiments, the electrode insulation channel 850 is arranged on the first electrode layer 821 or the second electrode layer 823. For example, when the acoustic transducing unit 820 is arranged on the upper surface of the support arm 830, the electrode insulation channel 850 is arranged on the first electrode layer 821; when the acoustic transducing unit 820 is arranged on the lower surface of the support arm 830, the electrode insulation channel 850 is arranged on the second electrode layer 823. The electrode insulation channel 850 is used to separate the first electrode layer 821 or the second electrode layer 823 into two or more electrode regions. The number of separated electrode regions can be two, three, five, etc. Through the above width design of the electrode insulation channel 850, it can be ensured that the existing processing technology can be processed, and at the same time, the influence on the SNR of the bone conduction microphone can be minimized.

[0213] The stress of the support arm 830 from the end connected to the base structure 810 to the end connected to the mass element 840 changes from tensile stress to compressive stress, or from compressive stress to tensile stress. The electrode layer (such as the first electrode layer 821) is distributed on the surface of the piezoelectric layer (such as the first piezoelectric layer 822) to collect electric charge, and the piezoelectric layer (such as the first piezoelectric layer 822) at different positions is subjected to different stresses, so the output electric charge is also different. In order to maximize the output sensitivity of the bone conduction microphone, the electrode layer (such as the first electrode layer 821) can be divided into multiple independent electrode layers covering the surface of the piezoelectric layer (such as the first piezoelectric layer 822) by the electrode insulation channel 850. During signal acquisition, appropriate independent partial electrode layers can be selected according to the positions of the independent partial electrode layers to output signals. When designing the electrode insulation channel 850, the partial electrode layer for outputting electric signals can be designed to cover as large an area of the support arm 830 as possible, thereby obtaining a larger output sensitivity and a smaller noise floor of the bone conduction microphone, thereby increasing the SNR.

[0214] It should be noted that the electrode insulation channel 850 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 850 can also not extend along the width direction of the support arm 830, for example Figure 14 It should be noted that the electrode insulation channel 850 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 850 can also not extend along the width direction of the support arm 830, for example

[0215] As shown in FIG. 8B, the acoustic transducing unit 820 is arranged on the lower surface of the support arm 830, and the electrode insulation channel 850 is arranged on the second electrode layer 823. Figure 14 As shown in FIG. 8B, the acoustic transducing unit 820 is arranged on the lower surface of the support arm 830, and the electrode insulation channel 850 is arranged on the second electrode layer 823. Figure 13When the acoustic transduction unit between the middle electrode insulating channel 850 and the mass element 840 is arranged at a position close to the mass element 840 of the support arm 830, the first electrode layer 821 and / or the second electrode layer 823 can further comprise an electrode lead 860. Taking the first electrode layer 821 as an example, the electrode insulating channel 850 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 by the electrode insulating channel 850 Figure 14 The first electrode layer 821 shown in the middle is located at the edge region of the support arm 830), which 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 L1 of the electrode lead 860 is less than or equal to 20 μm. In some embodiments, the width L1 of the electrode lead 860 can be 4 μm-20 μm. In some embodiments, the width L1 of the electrode lead 860 can be 4 μm-10 μm. In some embodiments, the electrode lead 860 can be located at any position in the width direction of the support arm 830, for example, the electrode lead 860 can be located at the center of the support arm 830 or close to the edge in the width direction. In some embodiments, the electrode lead 860 can be located close to the edge in the width direction of the support arm 830. By arranging the electrode lead 860, 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.

[0216] In some embodiments, the first electrode layer 821 has an electrode lead 860 for connecting the electrode area to the base structure 810. In some embodiments, the electrode lead 860 leads the electrical signal generated by the acoustic transduction unit 820 to the base structure 810, and the wire-bound electrode layer 826 can further lead the electrical signal out of the base structure 810. Through the width design of the electrode lead 860, the electrode area on the support arm 830 can be easily planned, and the processing of the electrode lead 860 is also facilitated.

[0217] In some embodiments, when the area of the first 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 better quality, the area of the first electrode layer 821 can be smaller than the area of the first piezoelectric layer 822, so that the edge area of the first electrode layer 821 avoids the edge area of the first piezoelectric layer 822, and an electrode recessed channel 870 (as shown in Figure 15 FIG. 21) can be formed between the first electrode layer 821 and the first piezoelectric layer 822. By setting the electrode recessed channel 870, the area of the first piezoelectric layer 822 with poor quality at the edge can be avoided from the first electrode layer 821 and the second electrode layer 823, so as to improve the signal-to-noise ratio of the output bone conduction microphone 800. In some embodiments, the width of the electrode recessed channel 870 can be 2-20 μιη. In some embodiments, the width of the electrode recessed channel 870 can be 2-10 μιη.

[0218] In some embodiments, the edge of the first piezoelectric layer 822 is formed with the electrode recessed channel 870. The first electrode layer 821 is located in the area within the electrode recessed channel 870 on the first piezoelectric layer 822. In some embodiments, the width of the electrode recessed channel 870 is less than 20 μιη. In some preferred embodiments, the width of the electrode recessed channel 870 can be 2-10 μιη. By designing the width of the electrode recessed channel 870, the electrode area on the support arm 830 can be easily planned, and the processing of the electrode recessed channel 870 is also facilitated.

[0219] In some embodiments, the bone conduction microphone 800 can simultaneously include the electrode insulation channel 850, the electrode lead 860 and the electrode recessed channel 870 structure in one or more embodiments of the present specification. The electrode insulation channel 850, the electrode lead 860 and the electrode recessed channel 870 can be prepared by etching. For example, etching can be sequentially performed on the first electrode layer 821, the first piezoelectric layer 822 and the second electrode layer 823. The etching of the first electrode layer 821, the first piezoelectric layer 822 and the second electrode layer 823 can adopt dry etching or wet etching. When the elastic layer 824 is provided, the elastic layer 824 can be further etched. In some embodiments, after the electrode insulation channel 850, the electrode lead 860 and the electrode recessed channel 870 are etched, the binding wire electrode layer 826 can be further provided on the first electrode layer 821.

[0220] As Figure 16As shown, the acoustic transducing unit 820 can further include an extension region 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 overlapping region of the first electrode layer 821, the first piezoelectric layer 822 and the second electrode layer 823 extends towards the mass element 840 to form the extension region 8210 on the mass element 840. The extension region 8210 can prevent stress concentration at the connection between the support arm 830 and the mass element 840. The extension region 8210 can be located on the upper surface of the mass element 840 or on the lower surface of the mass element 840. In some embodiments, the extension region 8210 located at the edge of the upper surface of the mass element 840 can be provided with an electrode insulation trench 850 to prevent excessive stress concentration of the support arm 830 and thus improve the stability of the support arm 830. In some embodiments, the length (length in the plane perpendicular to the thickness direction, see length W0 in Figure 16 ) of the extension region 8210 is greater than the width (width in the plane perpendicular to the thickness direction, see width W1 in Figure 16 ) of the support arm 830. Here the length of the extension region 8210 corresponds to the width of the support arm 830. In some embodiments, the length (length in the plane perpendicular to the thickness direction, see length W0 in Figure 16 ) of the extension region 8210 is 4-30 μm. In some embodiments, the length of the extension region 8210 is 4-15 μm. In some embodiments, the width (width in the plane perpendicular to the thickness direction, see width W1 in Figure 16 ) of the extension region 8210 on the mass element 840 is 1.2-2 times the width (width in the plane perpendicular to the thickness direction, see width W2 in Figure 16 ) of the support arm 830 at the edge of the mass element 840. In some embodiments, the width of the extension region 8210 on the mass element 840 is 1.2-1.5 times the width of the support arm 830 at the edge of the mass element 840. In some embodiments, the width of the extension region 8210 on the mass element 840 is equal to the width of the support arm 830 at the edge of the mass element 840.

[0221] Figure 17 is a structural schematic diagram of a bone conduction sound transducing device according to some embodiments of the present application, Figure 18 is a cross-sectional view of the bone conduction sound transducing device E-E shown in Figure 17 . Figure 17 and 18 is a bone conduction sound transducing device 1700 and Figure 8The bone conduction sound transmission devices 800 shown are substantially the same in overall structure, with the exception of the shape of the support arms. As shown in FIG. 8A, the support arms 830 are substantially straight. As shown in FIG. 8B, the support arms 840 are substantially curved. As shown in FIG. 8C, the support arms 850 are substantially straight, but have a different shape than the support arms 830 shown in FIG. 8A. As shown in FIG. 8D, the support arms 860 are substantially curved, but have a different shape than the support arms 840 shown in FIG. 8B. Figure 17 As shown, the base structure 1710 is a cuboid frame structure. In some embodiments, the interior of the base structure 1710 can include a hollow portion for suspending the acoustic transducing unit 1720 and the vibrating 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 vibrating unit can include four support arms 1730 and a mass element 1740, one end of the four support arms 1730 being connected to the upper surface, the lower surface, or the sidewall of the base structure 1710 where the hollow portion is located, the other end of the four support arms 1730 being connected to the upper surface, the lower surface, or the circumferential sidewall of the mass element 1740. In some embodiments, the mass element 1740 can be convex upward and / or downward relative to the support arms 1730. For example, when the ends of the four support arms 1730 are connected to the upper surface of the mass element 1740, the mass element 1740 can be convex downward relative to the support arms 1730. For another example, when the ends of the four support arms 1730 are connected to the lower surface of the mass element 1740, the mass element 1740 can be convex upward relative to the support arms 1730. For yet another example, when the ends of the four support arms 1730 are connected to the circumferential sidewall of the mass element 1740, the mass element 1740 can be convex upward and downward relative to the support arms 1730. In some embodiments, the upper surface of the mass element 1740 is at the same level as the upper surface of the support arms 1730, and / or the lower surface of the mass element 1740 is at the same level as the lower surface of the support arms 1730. In some embodiments, the shape of the support arms 1730 is trapezoidal, that is, the shape of the cross section of the support arms 1730 perpendicular to the thickness direction is trapezoidal. The smaller length end (the short side of the trapezoid) of the support arms 1730 is connected to the mass element 1740, and the larger length end (the long side of the trapezoid) of the support arms 1730 is connected to the base structure 1710. In other embodiments, the larger length end (the long side of the trapezoid) of the support arms 1730 is connected to the mass element 1740, and the smaller length end (the short side of the trapezoid) of the support arms 1730 is connected to the base structure 1710.

[0222] In some embodiments, the height of the trapezoid is greater than the length of the short side of the trapezoid (h > l) as shown in FIG. 8A, or the length of the long side of the trapezoid is greater than the height of the trapezoid (l > h) as shown in FIG. 8B. Figure 17The height h) of the trapezoid is 150 pm to 600 pm. In some embodiments, the height of the trapezoid is 200 pm to 500 pm. In some embodiments, the length of the long side of the trapezoid is 300 pm to 600 pm. In some embodiments, the length of the long side of the trapezoid is 350 pm to 550 pm. In some embodiments, the length of the short side of the trapezoid is 100 pm to 400 pm. In some embodiments, the length of the short side of the trapezoid is 150 pm to 300 pm. In some embodiments, the length of the short side of the trapezoid is 150 pm to 250 pm. By designing the relevant dimensions of the support arm 1730 (e.g., the length of the long side of the trapezoid, the length of the short side, the height h), the stiffness of the support arm 1730 can be adjusted, thereby adjusting the resonant frequency of the bone conduction sound transmission device 1700.

[0223] In some embodiments, the acoustic transducing unit 1720 can include a first electrode layer 1721, a first piezoelectric layer 1722, a second electrode layer 1723, an elastic layer 1731, a first seed layer (1724), and a wire electrode layer (not shown in the figure), etc. The materials, thicknesses, arrangement orders, manufacturing methods, etc. of the layers are the same as those of the acoustic transducing unit 1200. Figure 8 The embodiments shown are similar, and will not be described again here.

[0224] In some embodiments, in order to improve the signal-to-noise ratio of the bone conduction sound transmission device 1700, the effective acoustic transducing unit can be arranged at a position close to the mass element 1740 or close to the connection between the support arm 1730 and the base structure 1710. In some embodiments, the effective acoustic transducing unit is arranged at a position close to the mass element 1740 of the support arm 1730. In some embodiments, when the effective acoustic transducing unit is arranged at a position close to the mass element 1740 or close to the connection between the support arm 1730 and the base structure 1710, the ratio of the coverage area of the effective acoustic transducing unit to the area of the support arm 1730 is 5% to 40%. In some embodiments, the ratio of the coverage area of the effective acoustic transducing unit to the area of the support arm 1730 (the area of the cross section of the support arm 1730 perpendicular to the thickness direction) is 10% to 35%. In further embodiments, the ratio of the coverage area of the effective acoustic transducing unit to the area of the support arm 1730 (the area of the cross section of the support arm 1730 perpendicular to the thickness direction) is 15% to 20%.

[0225] The signal-to-noise ratio of the bone conduction sound transmission device 1700 is positively correlated with the strength of the output electric signal. When the relative motion occurs between the laminated structure and the base structure 1710, the deformation stress at the connection between the support arm 1730 and the mass element 1740 and the connection between the support arm 1730 and the base structure 1710 is larger than the deformation stress at the middle region of the support arm 1730. Further, the strength of the output voltage at the connection between the support arm 1730 and the mass element 1740 and the connection between the support arm 1730 and the base structure 1710 is also larger than the strength of the output voltage at the middle region of the support arm 1730. In some embodiments, as shown in Figure 19 In order to improve the signal-to-noise ratio of the bone conduction sound transmission device 1700, an electrode insulation channel 1750 can be arranged on the first electrode layer when the acoustic transducing unit 1720 completely or nearly completely covers the upper surface or the lower surface of the support arm 1730. The electrode insulation channel 1750 separates the first electrode layer 1721 into at least two parts, so that one part of the first electrode layer 1721 is close to the mass element 1740, and the other part of the first electrode layer 1721 is close to the connection between the support arm 1730 and the base structure 1710. In some embodiments, the electrode insulation channel 1750 can be a straight line extending along the width direction of the support arm 1730. In some embodiments, the width of the electrode insulation channel 1750 can be 2 μm-20 μm. In some embodiments, the width of the electrode insulation channel 1750 can be 4 μm-10 μm.

[0226] It should be noted that the electrode insulation channel 1750 is not limited to a straight line extending along the width direction of the support arm 1730, but can also be a curve, a bent line, a wavy line, etc. In addition, the electrode insulation channel 1750 can also not extend along the width direction of the support arm 1730, for example Figure 19 As shown in

[0227] As shown in Figure 20 The partial structure of the acoustic transducing unit 1720 (for example, Figure 19When the acoustic transduction unit between the middle electrode insulating channel 1750 and the mass element 1740 is arranged at the position of the support arm 1730 close to the mass element 1740, the first electrode layer 1721 and / or the second electrode layer 1723 can further include an electrode lead 1760. Taking the first electrode layer 1721 as an example, the first electrode layer 1721 is divided into two parts by the middle electrode insulating channel 1750, one part of the first electrode layer 1721 is connected to or close to the mass element 1740, and the other part of the first electrode layer 1721 is close to the connection between the support arm 1730 and the base structure 1710. In order to output the voltage close to the mass element 1740 in the acoustic transduction unit 1720, the first electrode layer 1721 close to the connection between the support arm 1730 and the base structure 1710 can be divided into a partial area by the middle electrode insulating channel 1750 (the first electrode layer 1721 shown in the figure is located at the edge area of the support arm 1730, which is marked as the electrode lead 1760), and the electrode lead 1760 electrically connects the part of the acoustic transduction unit 1720 connected to or close to the mass element 1740 to the processing unit of the bone conduction microphone 1700. In some embodiments, the width L2 of the electrode lead 1760 can be 4-20 μm. In some embodiments, the width L2 of the electrode lead 1760 can be 4-10 μm. In some embodiments, the electrode lead 1760 can be located at any position in the width direction of the support arm 1730, for example, the electrode lead 1760 can be located at the center or close to the edge in the width direction of the support arm 1730. In some embodiments, the electrode lead 1760 can be located close to the edge in the width direction of the support arm 1730. By arranging the electrode lead 1760, the use of conductive wires in the acoustic transduction unit 1720 can be avoided, and the structure is relatively simple, which is convenient for subsequent production and assembly.

[0228] The piezoelectric material of the first piezoelectric layer 1722 close to the edge area of the support arm 1730 can cause surface roughness due to etching, which can cause the quality of the piezoelectric material to deteriorate. In some embodiments, when the area of the first piezoelectric layer 1722 is the same as the area of the second electrode layer 1723, in order to make the first electrode layer 1721 located in the area of the first piezoelectric layer 1722 with better quality piezoelectric material, the area of the first electrode layer 1721 can be smaller than the area of the first piezoelectric layer 1722, so that the edge area of the first electrode layer 1721 avoids the edge area of the first piezoelectric layer 1722, and an electrode recess channel can be formed between the first electrode layer 1721 and the first piezoelectric layer 1722 (the structure of the electrode recess channel is similar to the electrode lead 1760, and the electrode recess channel is not shown in the figure). Figure 15(The structure of the middle electrode recessed channel 870 is similar). By setting the electrode recessed channel, the area with poor edge quality of the first piezoelectric layer 1722 can be avoided from the first electrode layer 1721 and the second electrode layer 1723, thereby improving the signal-to-noise ratio of the output bone conduction sound transmission device 1700. In some embodiments, the width of the electrode recessed channel can be 2μm-20μm. In some embodiments, the width 11212 of the electrode recessed channel can be 2μm-10μm.

[0229] like Figure 20 As shown, in some embodiments, taking the mass element 1740 protruding downward relative to the support arm 1730 as an example, the acoustic transducer unit 1720 may further include an extension region 17210 extending along the length direction of the support arm 1730, the extension region 17210 being located on the upper surface of the mass element 1740. In some embodiments, the overlapping region of the first electrode layer 1721, the first piezoelectric layer 1722, and the second electrode layer 1723 extends toward the mass element 1740 to form the extension region 17210. The extension region 17210 may be located on the upper surface or the lower surface of the mass element 1740. In some embodiments, an electrode insulation channel 1750 may be provided at the edge of the extension region 17210 on the upper surface of the mass element 1740, thereby preventing excessive stress concentration in the support arm 1730 and improving the stability of the support arm 1730. In some embodiments, the width of the extension region 17210 (width in a plane perpendicular to the thickness direction, see...) Figure 20 The width W3 shown is greater than the width of the support arm 1730 (the width on the plane perpendicular to the thickness direction, see [reference]). Figure 20 The width shown is W4). Here, the width of the extension region 17210 corresponds to the width of the support arm 1730. In some embodiments, the width of the extension region 17210 is 4μm-30μm. In some embodiments, the width of the extension region 17210 is 4μm-15μm. In some embodiments, the width of the extension region 17210 on the mass element 1740 is 1.2-2 times the width of the edge connection between the support arm 1730 and the mass element 1740. In some embodiments, the width of the extension region 17210 on the mass element 1740 is 1.2-1.5 times the width of the edge connection between the support arm 1730 and the mass element 1740. For the material, size, and other parameters of the acoustic transducer unit 1720, the first electrode layer 1721, the second electrode layer 1723, the first piezoelectric layer 1722, the vibration unit, and the mass element 1740 in this embodiment, please refer to... Figure 8- Figure 16 The details are omitted here.

[0230] Figure 21 This is a schematic diagram of the structure of a bone conduction sound transmission device according to some embodiments of this application.Figure 22 is according to Figure 21 is a front view of a bone conduction sound transmission device. Figure 21-22 The bone conduction sound transmission device 2100 shown in Figure 8 The structure of the bone conduction sound transmission device 800 shown in is substantially the same as that of the bone conduction sound transmission device 2100 shown in Figure 21 As shown in, the base structure 2110 is a cuboid frame structure. In some embodiments, the inside of the base structure 2110 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 2130 and a mass element 2140, one end of the four support arms 2130 being connected with the upper surface, the lower surface of the base structure 2110 or the side wall where the hollow portion of the base structure 2110 is located, and the other end of the four support arms 2130 being connected with the upper surface, the lower surface or the circumferential side wall of the mass element 2140. In some embodiments, the mass element 2140 can protrude upward and / or downward relative to the support arms 2130. For example, when the ends of the four support arms 2130 are connected with the upper surface of the mass element 2140, the mass element 2140 can protrude downward relative to the support arms 2130. For another example, when the ends of the four support arms 2130 are connected with the lower surface of the mass element 2140, the mass element 2140 can protrude upward relative to the support arms 2130. For yet another example, when the ends of the four support arms 2130 are connected with the circumferential side wall of the mass element 2140, the mass element 2140 can protrude upward and downward relative to the support arms 2130. In some embodiments, the shape of the support arms 2130 is trapezoidal, that is, the shape of the cross section of the support arms 2130 perpendicular to the thickness direction is trapezoidal. Among them, the longer end (the long side of the trapezoid) of the support arms 2130 is connected with the mass element 2140, and the shorter end (the short side of the trapezoid) of the support arms 2130 is connected with the base structure 2110. In other embodiments, the shorter end (the short side of the trapezoid) of the support arms 2130 is connected with the mass element 2140, and the longer end (the long side of the trapezoid) of the support arms 2130 is connected with the base structure 2110. It should be noted that, Figure 8- Figure 10 The structure, size, thickness and other parameters of the acoustic transducing unit 820, the first electrode layer 821, the second electrode layer 823, the first piezoelectric layer 822, the vibration unit, the mass element 840, the extension area 8210, the electrode insulation channel 850, the electrode lead 860, the electrode indentation channel 870 and other components can be applied to the bone conduction sound transmission device 2100, and will not be further described here.

[0231] In some preferred embodiments, when the cross-section of the support arm perpendicular to the thickness direction is polygonal (such as rectangular or trapezoidal), the mass element can be configured to protrude upwards or downwards relative to the support arm. This configuration of the mass element allows for greater deformation stress during support arm deformation, thereby resulting in a stronger electrical signal output by the acoustic transducer unit.

[0232] Figure 23 This is a schematic diagram of the structure of a bone conduction sound transmission device according to some embodiments of this application. Figure 24 It is based on Figure 23 The front view of the bone conduction sound transmission device shown. Figure 25 yes Figure 24 The cross-sectional view of the bone conduction sound transmission device at FF is shown. Figure 23-25 The structure of the bone conduction sound transmission device 2300 shown is similar to Figure 8 The bone conduction sound transmission device 800 shown has a generally similar structure, the difference being that the support arm 2330 of the bone conduction sound transmission device 2300 has a different structure and shape than the support arm 830 in the bone conduction sound transmission device 800. In some embodiments, the interior of the base structure 2310 may include a hollow portion for suspending the acoustic transducer unit 2320 and the vibration unit. In some embodiments, the vibration unit may include four support arms 2330 and a mass element 2340. One end of the four support arms 2330 is connected to the upper surface, lower surface, or sidewall of the hollow portion of the base structure 2310, and the other end of the four support arms 2330 is connected to the upper surface, lower surface, or circumferential sidewall of the mass element 2340. In some embodiments, the mass element 2340 may protrude upward and / or downward relative to the support arms 2330. For example, when the ends of the four support arms 2330 are connected to the upper surface of the mass element 2340, the mass element 2340 may protrude downward relative to the support arms 2330. For example, when the ends of the four support arms 2330 are connected to the lower surface of the mass element 2340, the mass element 2340 may protrude upward relative to the support arms 2330. As another example, when the ends of the four support arms 2330 are connected to the circumferential sidewalls of the mass element 2340, the mass element 2340 may protrude upward and downward relative to the support arms 2330. In some embodiments, the upper surface of the mass element 2340 is on the same horizontal plane as the upper surface of the support arms 2330, and / or the lower surface of the mass element 2340 is on the same horizontal plane as the lower surface of the support arms 2330. In some embodiments, the support arms 2330 may have an approximately L-shaped structure. Figure 23As shown, the support arm 2330 may include a first strip portion 2331 and a second strip portion 2332. One end of the first strip portion 2331 is connected to one end of the second strip portion 2332, wherein the first strip portion 2331 and the second strip portion 2332 have a certain included angle. In some embodiments, the included angle ranges from 75° to 105°. In some embodiments, one end of the first strip portion 2331 away from the connection between the first strip portion 2331 and the second strip portion 2332 is connected to the base structure 2310, and one end of the second strip portion 2332 away from the connection between the first strip portion 2331 and the second strip portion 2332 is connected to the upper surface, lower surface, or peripheral sidewall of the mass element 2340, such that the mass element 2340 is suspended in the hollow portion of the base structure 2310.

[0233] In some embodiments, such as Figure 23-25 As shown, the support arm 2330 includes two strip-shaped portions: a first strip-shaped portion 2331 and a second strip-shaped portion 2332. In some embodiments, one end of the first strip-shaped portion 2331 is connected to the mass element 2340, while the other end is connected to one end of the second strip-shaped portion 2332; the other end of the second strip-shaped portion 2332 is connected to the base structure 2310. Compared to a polygonal support arm, the support arm 2330, including the first strip-shaped portion 2331 and the second strip-shaped portion 2332, can be designed to be longer within a limited space. Therefore, the stiffness of the support arm 2330 can be smaller, and the mass element 2340 can be correspondingly smaller (e.g., it may not need to protrude upwards or downwards relative to the support arm 2330, thus eliminating the need for further processing of the upward or downward protruding structure of the mass element 2340), thereby simplifying the manufacturing process of the mass element 2340.

[0234] In this embodiment, the support arm 2330 and the mass element 2340 can be fabricated according to the fabrication process described above. Furthermore, in this embodiment, if it is not necessary to provide a mass element 2340 that protrudes upwards or downwards relative to the support arm 2330, the support arm 2330 and the mass element 2340 can be fabricated simultaneously on the same substrate material, thereby simplifying the processing technology.

[0235] The connection point between the first strip portion 2331 and the mass element 2340 can be located at any position on the side of the polygon, such as the end of the side or the midpoint of the side. In some embodiments, the connection point between the first strip portion 2331 and the mass element 2340 is located at the end of the side of the polygon (e.g., at the end of the side). Figure 24In some embodiments, the width N1 of the first strip portion 2331 is 50-300 μm. In some embodiments, the width N1 of the first strip portion 2331 is 80-200 μm. In some embodiments, the width N2 of the second strip portion 2332 is 50-300 μm. In some embodiments, the width N2 of the second strip portion 2332 is 80-200 μm. In some embodiments, the length L1 of the first strip portion 2331 is 20-200 μm. In some embodiments, the length L1 of the first strip portion 2331 is 30-100 μm. In some embodiments, the length L2 of the second strip portion 2332 is 800-1300 μm. In some embodiments, the length L2 of the second strip portion 2332 is 900-1200 μm.

[0236] In some embodiments, the angle between the first strip portion 2331 and the second strip portion 2332 (the length direction angle) can be 60-120°. In some embodiments, the angle between the first strip portion 2331 and the second strip portion 2332 (the length direction angle) can be 75-105°. In some embodiments, the angle between the first strip portion 2331 and the second strip portion 2332 (the length direction angle) can be 90° (i.e. the length direction of the first strip portion 2331 is perpendicular to the length direction of the second strip portion 2332).

[0237] In some embodiments, one end of the first strip portion 2331 is connected to the mass element 2340, and the other end of the first strip portion 2331 can be connected to a position other than the end of the second strip portion 2332 (e.g. the other end of the first strip portion 2331 is connected to the middle of the length direction of the second strip portion 2332). One end of the second strip portion 2332 is connected to the base structure 2310 (or both ends of the second strip portion 2332 are connected to the base structure 2310). It can be understood that in this way, the support arm 2330 is in the shape of a "T".

[0238] Figure 30 is a structural schematic diagram of a bone conduction sound transmission device 2300 according to some other embodiments of the present application. Figure 30 The embodiments shown differ from the embodiments shown in Figure 24 The difference between the embodiments shown is the connection position of the support arm and the mass element. As shown in Figure 30As shown, the connection between the first bar-shaped portion 2331 and the mass element 2340 is located at the middle region of the side of the polygon of the mass element 2340 (e.g., at the midpoint of the side). In some embodiments, the width N3 of the first bar-shaped portion 2331 is 100-400 μm. In some embodiments, the width N3 of the first bar-shaped portion 2331 is 150-300 μm. In some embodiments, the width N4 of the second bar-shaped portion 2332 is 100-400 μm. In some embodiments, the width N4 of the second bar-shaped portion 2332 is 150-300 μm. In some embodiments, the length L3 of the first bar-shaped portion 2331 is 20-200 μm. In some embodiments, the length L3 of the first bar-shaped portion 2331 is 30-100 μm. In some embodiments, the length L4 of the second bar-shaped portion 2332 is 500-1000 μm. In some embodiments, the length L4 of the second bar-shaped portion 2332 is 700-900 μm.

[0239] In some embodiments, the angle between the first bar-shaped portion 2331 and the second bar-shaped portion 2332 can be substantially the same as the angle between two adjacent sides of the polygon. For example, when the polygon is a regular hexagon, the angle between two adjacent sides can be 120°, and the angle between the first bar-shaped portion and the second bar-shaped portion can be approximately 120°. In some embodiments, when the cross-section of the mass element 2340 perpendicular to the thickness direction is rectangular, the first bar-shaped portion 2331 and the second bar-shaped portion 2332 are perpendicular. With such a design, the layout of the bone conduction sound device 2300 is more compact.

[0240] Figure 26 is a structural schematic diagram of a bone conduction sound device according to Figure 23 is a structural schematic diagram of a bone conduction sound device according to Figure 27 is a structural schematic diagram of a bone conduction sound device according to Figure 23 is a structural schematic diagram of a bone conduction sound device according to Figure 28 is a structural schematic diagram of a bone conduction sound device according to Figure 23 is a structural schematic diagram of a bone conduction sound device according to Figure 29 is a structural schematic diagram of a bone conduction sound device according to Figure 23 is a structural schematic diagram of a bone conduction sound device according to Figure 26 mainly shows the electrode insulation groove 2350 when the support arm 2330 includes two bar-shaped portions, Figure 27 mainly shows the electrode insulation groove 2350 and the electrode lead 2360 when the support arm 2330 includes two bar-shaped portions, Figure 28 mainly shows the electrode insulation groove 2350 and the electrode lead 2360 when the support arm 2330 includes two bar-shaped portions, Figure 29 mainly shows the electrode insulation groove 2350 and the electrode lead 2360 when the support arm 2330 includes two bar-shaped portions, Figure 26-29As shown, in some embodiments, the acoustic transducing unit 2320 is a multi-layer structure, which can include a first electrode layer 2321, a second electrode layer 2323, a first piezoelectric layer 2322, an elastic layer 2324, a seed layer, a wire electrode layer 2326, an extension region 2380, an electrode insulation trench 2350, an electrode lead 2360, an electrode recess trench 2370, etc. For the structure of each layer of the acoustic transducing unit 2320, the mass element 2340, etc., reference can be made to the description of the structure of the 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 trench 850, the electrode lead 860, the electrode recess trench 870, etc. in the description of the bone conduction sound transducing device 2100. Figure 8- Figure 10 The structure, size, thickness, etc. of the 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 trench 850, the electrode lead 860, the electrode recess trench 870, etc. can be described as in the description of the bone conduction sound transducing device 2100. Figure 23 As shown, the bone conduction sound transducing device 2300, which will not be further described herein.

[0241] Figure 31 is a structural schematic diagram of the bone conduction sound transducing device 3100 according to some embodiments of the present application. The bone conduction sound transducing device 3100 includes a base structure 3110. As shown, Figure 31 As shown, in some embodiments, the support arm 3130 includes three strip-shaped parts, which include a first strip-shaped part 3131, a second strip-shaped part 3132, and a third strip-shaped part 3133; one end of the first strip-shaped part 3131 is connected to the mass element 3140, and the other end thereof is connected to one end of the second strip-shaped part 3132; the other end of the second strip-shaped part 3132 is connected to one end of the third strip-shaped part 3133; the other end of the third strip-shaped part 3133 is connected to the base structure 3110. Through such a structural design, the support arm 3130 can be designed to be longer in a limited space, the rigidity of the support arm 3130 can thus be smaller, and the mass of the mass element 3140 can be correspondingly set to be smaller (e.g., can not need to be protruded upward and downward relative to the support arm), so that the manufacturing process of the mass element 3140 can be further simplified.

[0242] The connection between the first strip-shaped part 3131 and the mass element 3140 can be located at any position of the side of the polygon, such as the end of the side or the midpoint of the side, etc. In some embodiments, as shown, Figure 31As shown, the connection of the first bar portion 3131 to the mass element 3140 is at the end of a side of the polygon. In some embodiments, the width N5 of the first bar portion 3131 can be 50-300 pm. In some embodiments, the width N5 of the first bar portion 3131 is 80-150 pm. In some embodiments, the width N6 of the second bar portion 3132 can be 50-300 pm. In some embodiments, the width N6 of the second bar portion 3132 is 80-150 pm. In some embodiments, the widths N7 of the third bar portions 3133 can each be 50-300 pm. In some embodiments, the widths N7 of the third bar portions 3133 are 80-150 pm. In some embodiments, the length L5 of the first bar portion 3131 can be 20-200 pm. In some embodiments, the length L5 of the first bar portion 3131 is 30-100 pm. In some embodiments, the length L6 of the second bar portion 3132 is 600-1200 pm. In some embodiments, the length L6 of the second bar portion 3132 is 800-1000 pm. In some embodiments, the lengths L7 of the third bar portions 3133 can be 800-1300 pm. In some embodiments, the lengths L7 of the third bar portions 3133 are 900-1200 pm.

[0243] Figure 32 is a structural schematic diagram of a bone conduction sound transmission device 3100 according to yet some embodiments of the present application. As shown, the device 3100 includes a mass element 3140, a first bar portion 3131, a second bar portion 3132, and third bar portions 3133. The first bar portion 3131 is connected to the mass element 3140 at a first end 3134 of the first bar portion 3131. The second bar portion 3132 is connected to the mass element 3140 at a second end 3135 of the second bar portion 3132. The third bar portions 3133 are connected to the mass element 3140 at third ends 3136 of the third bar portions 3133. The first bar portion 3131 is connected to the second bar portion 3132 at a fourth end 3137 of the first bar portion 3131. The second bar portion 3132 is connected to the third bar portions 3133 at fifth ends 3138 of the second bar portion 3132. The third bar portions 3133 are connected to each other at sixth ends 3139 of the third bar portions 3133. Figure 32As shown, the connection between the first bar-shaped part 3131 and the mass element 3140 is located at the midpoint of the side of the polygon. In some embodiments, the width N8 of the first bar-shaped part 3131 is 50-300 μm. In some embodiments, the width N8 of the first bar-shaped part 3131 is 80-150 μm. In some embodiments, the width N9 of the second bar-shaped part 3132 is 50-300 μm. In some embodiments, the width N9 of the second bar-shaped part 3132 is 80-150 μm. In some embodiments, the width N10 of the third bar-shaped part 3133 is 50-300 μm. In some embodiments, the width N10 of the third bar-shaped part 3133 is 80-150 μm. In some embodiments, the length L8 of the first bar-shaped part 3131 is 20-200 μm. In some embodiments, the length L8 of the first bar-shaped part 3131 is 30-100 μm. In some embodiments, the length L9 of the second bar-shaped part 3132 is 500-1000 μm. In some embodiments, the length L9 of the second bar-shaped part 3132 is 600-800 μm. In some embodiments, the length L10 of the third bar-shaped part 3133 is 800-1300 μm. In some embodiments, the length L10 of the third bar-shaped part 3133 is 900-1200 μm.

[0244] In some embodiments, the angle between the first bar-shaped part 3131 and the second bar-shaped part 3132, and the angle between the second bar-shaped part 3132 and the third bar-shaped part 3133 can be substantially the same as the angle between two adjacent sides of the polygon. For example, when the polygon is a regular hexagon, the angle between two adjacent sides can be 120°, then the angle between the first bar-shaped part 3131 and the second bar-shaped part 3132 can be approximately 120°, and the angle between the second bar-shaped part 3132 and the third bar-shaped part 3133 can be approximately 120°. In some embodiments, in order to make the structure of the bone conduction sound device 3100 more compact, the cross section of the mass element 3140 perpendicular to the thickness direction is rectangular, the second bar-shaped part 3132 is perpendicular or substantially perpendicular to the first bar-shaped part 3131, and the second bar-shaped part 3132 is perpendicular or substantially perpendicular to the third bar-shaped part 3133.

[0245] In some embodiments, the support arm can further include more bar-shaped parts, such as a fourth bar-shaped part, a fifth bar-shaped part, etc. The number of bar-shaped parts included in the support arm can be specifically designed according to the rigidity of the support part.

[0246] Figure 33 is according to Figure 32 Another structural schematic diagram of the bone conduction sound device 3100 is shown. Figure 33The electrode insulation channel 3150 is shown. In some embodiments, the acoustic transducing unit 3120 is a multi-layer structure, which can include a first electrode layer, a second electrode layer, a first piezoelectric layer, an elastic layer, a seed layer, an electrode insulation channel 3150, an electrode indentation channel, etc. For the structure, size, thickness, etc. of the layers of the acoustic transducing unit 3120, the mass element 3140, etc., reference can be made to the description of the acoustic transducing unit 3120 in the present specification Figure 8- Figure 10 The structure, size, thickness, etc. of the components of the 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 850, the electrode lead 860, the electrode indentation channel 870, etc. are not further described herein.

[0247] In some embodiments, the sum of the thickness of the support arm and the acoustic transducing unit is less than the thickness of the mass element. It can be appreciated that when the acoustic transducing unit is disposed on the upper surface or the lower surface of the support arm, the sum of the thickness of the support arm and the acoustic transducing unit can be the sum of the thickness of the two. When the acoustic transducing unit is disposed inside the support arm, the sum of the thickness of the support arm and the acoustic transducing unit can be the thickness of the support arm including the acoustic transducing unit inside. When the shape of the cross section of the support arm perpendicular to the thickness direction is a polygon such as a rectangle or a trapezoid, the rigidity of the support arm can be larger, and thus the thickness of the mass element can be correspondingly set to be thicker, so that the mass of the mass element is larger, thereby enabling the resonance frequency of the bone conduction sound transmission device to be within the range defined in one or more of the above embodiments. In some embodiments, the sum of the thickness of the support arm and the acoustic transducing unit is greater than or equal to the thickness of the mass element. When the support arm includes two strip-shaped portions (e.g., the support arm includes a first strip-shaped portion and a second strip-shaped portion), or the support arm includes three strip-shaped portions (e.g., the support arm includes a first strip-shaped portion, a second strip-shaped portion, and a third strip-shaped portion), or the support arm includes a larger number of strip-shaped portions, the rigidity of the support arm can be smaller, and thus the thickness of the mass element can be correspondingly set to be thinner, so that the mass of the mass element is smaller, thereby enabling the resonance frequency of the bone conduction sound transmission device to be within the range defined in one or more of the above embodiments.

[0248] In some embodiments, the bone conduction sound transmission device of any of the above embodiments may further include a limiting structure (not shown in the figures), which is a plate-like structure. In some embodiments, the limiting structure may be located in the hollow portion of the base structure, and may be located above or below the stacked structure, and disposed opposite to the stacked structure. In some embodiments, when the base structure is a vertically continuous structure, the limiting structure may also be located at the top or bottom of the base structure. The limiting structure and the mass units of the stacked structure are spaced apart, and the limiting structure can limit the amplitude of the mass units in the stacked structure when subjected to a large impact, avoiding severe vibration that could damage the device. In some embodiments, the limiting structure may be a rigid structure (e.g., a limiting block) or a structure with a certain degree of elasticity (e.g., an elastic pad, a buffer cantilever beam, or a combination of a buffer support arm and a limiting block).

[0249] The layered structure has a natural frequency. When the frequency of an external vibration signal approaches this natural frequency, the layered structure generates a large amplitude, thereby outputting a large electrical signal. Therefore, the response of a bone conduction microphone to external vibrations manifests as the generation of a resonant peak near its natural frequency. In some embodiments, by changing the parameters of the layered structure, the natural frequency of the layered structure can be shifted to the speech frequency range, so that the resonant peak of the bone conduction microphone is located within the speech frequency range, thereby improving the sensitivity of the bone conduction microphone to vibrations in the speech frequency range (e.g., the frequency range preceding the resonant peak). Figure 34 As shown, the frequency response curve of the stacked structure with its natural frequency advanced ( Figure 34 The frequency response curve (the solid line curve in the image) showing the resonance peak 3401, where the frequency remains unchanged relative to the natural frequency of the stacked structure. Figure 17 The frequency corresponding to the resonance peak 3402 in the dashed curve is relatively low. For external vibration signals with frequencies lower than the frequency of resonance peak 3401, the bone conduction device corresponding to the solid curve will have higher sensitivity.

[0250] The displacement output formula for the stacked structure is as follows:

[0251]

[0252] 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, and x a Let 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. When the angular frequency of the external force ω < ω0... 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 aincreases. When the frequency of the exciting force ω = ω0, ωM= Kω -1 . Changing the natural frequency ω0of the vibration-electric signal conversion device (laminated structure) does not change the displacement output x a . When the frequency of the exciting force ω > ω0, ωM> Kω -1 . If the natural frequency ω0of the vibration-electric signal conversion device is reduced (which can be achieved by increasing M or reducing K or both), |ωM- Kω -1 | increases, and the displacement output x a decreases.

[0253] As the resonance peak is advanced, a peak value appears in the speech frequency band. When picking up signals, the bone conduction sound transmission device has too much signal in the resonance peak frequency band, which makes the call effect poor. In some embodiments, in order to improve the quality of the sound signal collected by the bone conduction sound transmission device, a damping structure layer can be arranged at the laminated structure, which can increase the energy loss of the laminated structure during vibration, especially in the resonance frequency band. Here, the damping coefficient is described by using the reciprocal of the mechanical quality factor 1 / Q as follows:

[0254]

[0255] where Q -1 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.

[0256] The laminated structure loss factor η is related to the damping material loss factor tanδ as follows:

[0257]

[0258] where X is a shear parameter related to the thickness and material properties of each layer of the laminated structure, and Y is a stiffness parameter related to the thickness and Young's modulus of each layer of the laminated structure.

[0259] From formulas (5) and (6), it can be seen that by adjusting the material of the damping structure layer and the material of each layer of the laminated structure, the laminated structure loss factor η can be adjusted within a suitable range. As the damping of the damping structure layer of the laminated structure increases, 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 taking advantage of the characteristics of the laminated structure that the amplitude is small in the non-resonance region and large in the resonance region, the Q value in the resonance region can be reduced while ensuring that the sensitivity of the bone conduction sound transmission device in the non-resonance region is not reduced by increasing the damping structure layer, so that the frequency response of the bone conduction sound transmission device is relatively flat in the entire frequency band. Figure 35is a frequency response curve diagram of the bone conduction microphone device with or without the damping structure layer according to some embodiments of the present application. As shown in Figure 35 , the frequency response curve 3502 of the electrical signal output by the bone conduction microphone device with the damping structure layer is relatively flat compared with the frequency response curve 3501 of the electrical signal output by the bone conduction microphone device without the damping structure layer.

[0260] In some embodiments, the bone conduction microphone device 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 on the upper surface and / or lower surface of the laminated structure or between the multiple layers of the laminated structure. In some embodiments, for the macro-sized laminated structure and base structure, the damping structure layer can be directly bonded on 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. In some embodiments, the output effect of the electrical signal of the bone conduction microphone device can be improved by selecting the material, size, thickness, etc. of the damping film.

[0261] In order to more clearly describe the damping structure layer, the bone conduction microphone device in the form of a cantilever beam (for example, the bone conduction microphone device 100 as shown in Figure 1 , the bone conduction microphone device 300 as shown in Figure 3 , the bone conduction microphone device 400 as shown in Figure 4 ) is taken as an exemplary illustration. Figure 36 is a cross-sectional view of the bone conduction microphone device according to some embodiments of the present application. As shown in Figure 36 , the bone conduction microphone device 3600 can include a base structure 3610, a laminated structure 3620, and a damping structure layer 3630. Further, one end of the laminated structure 3620 is connected with the upper surface of the base structure 3610, and the other end of the laminated structure 3620 is suspended in the hollow portion of the base structure 3610, and the damping structure layer 3630 is located on the upper surface of the laminated structure 3620. The area of the damping structure layer 3630 can be greater than the area of the laminated structure 3620, i.e. the damping structure layer 3630 can not only cover the upper surface of the laminated structure 3620, but also further cover the gap between the laminated structure 3620 and the base structure 3610. In some embodiments, at least part of the peripheral side of the damping structure layer 3630 can be fixed on the base structure 3610.

[0262] Figure 37 is a cross-sectional view of the bone conduction microphone device according to some embodiments of the present application. As shown inFigure 37 As shown in FIG. 37, the bone conduction microphone 3700 can include a base structure 3710, a laminated structure 3720, and two damping structure layers, wherein the two damping structure layers include a first damping structure layer 3730 and a second damping structure layer 3740. Further, the second damping structure layer 3740 is connected to an upper surface of the base structure 3710, and a lower surface of the laminated structure 3720 is connected to an upper surface of the second damping structure layer 3740, wherein one end of the laminated structure 3720 is suspended in a hollow portion of the base structure 3710, and the first damping structure layer 3730 is located on an upper surface of the laminated structure 3720. The area of the first damping structure layer 3730 and / or the second damping structure layer 3740 is greater than the area of the laminated structure 3720.

[0263] Figure 38 FIG. 38 is a cross-sectional view of a bone conduction microphone according to some embodiments of the present disclosure. As shown in FIG. 38, the bone conduction microphone 3800 can include a base structure 3810, a laminated structure 3820, and a damping structure layer 3830. Further, the damping structure layer 3830 is located on an upper surface of the base structure 3810. A lower surface of the laminated structure 3820 is connected to an upper surface of the damping structure layer 3830, and one end of the laminated structure 3820 is suspended in a hollow portion of the base structure 3810. Figure 38

[0264] It should be noted that the position of the damping structure layer (e.g., the damping structure layer 3630) is not limited to the upper surface and / or the lower surface of the laminated structure as described above, but can also be located between the multi-layer structure of the laminated structure. For example, the damping structure layer can be located between the elastic layer and the first electrode layer. For another example, the damping structure layer can also be located between the first elastic layer and the second elastic layer. In addition, the damping structure layer is not limited to the cantilever beam type bone conduction microphone as described above, but can also be applied to the bone conduction microphone as shown in FIGS. 39-42, which will not be described herein. Figure 36- Figure 38 Figure 5 Figure 7 Figure 8 Figure 17 Figure 21 Figure 23 Figure 31

[0265] The foregoing detailed description has set forth various embodiments of the devices and / or methods via the use of specific terminology. However, the embodiments disclosed herein are merely exemplary and need not be construed as limiting the scope of the disclosure. It should be apparent that the scope of the disclosure is not limited to the specific embodiments described herein. The description is not intended as an exhaustive description of the ascertained devices and / or methods. Changes can be made in the device and / or method described, and equivalents can be substituted for elements thereof, without departing from the scope of the disclosure. It should be appreciated that those skilled in the art can be able to devise numerous devices and / or methods that, although not explicitly set forth herein, embody the principles of the disclosure and have the same broad scope and scope as the ascertained devices and / or methods. The devices and / or methods disclosed herein are further defined by the following claims.

[0266] ​​​​​​​​​Also, certain terminology has been used for the purpose of reference only, and thus is not intended to be limiting. For example, terms such as "upper," "lower," "front," "back," "side," "end," "one or more," "first," "second," etc., are used only to facilitate discussion, and thus should not be construed as a limitation of the present application. Similarly, "one embodiment" is used solely to refer to the embodiment(s) discussed and not to imply that other embodiments are not possible. So that the application can be more readily understood, certain terms are first defined. The definitions provided herein are to be used as follows.

[0267] Furthermore, those skilled in the art will recognize that aspects of the present application, in some tacks and contexts, can be described using, for convenience, future conditional language. Such future conditional language is used herein to exemplify embodiments and should not be construed as a prediction or forecast of such embodiments. Indeed, that which is cannot possibly be predicted or forecast, especially not with certainty. It is further noted that the present application can be implemented in software and / or firmware. The software implementation can be in a manner similar to that described in the above referenced U.S. Patent Application Serial No. 11 / 032,337, filed January 11, 2005, entitled "Method and Apparatus for Providing a User Interface for a Mobile Device," which is incorporated herein by reference. Accordingly, various inventive concepts have been described herein with reference to various embodiments. Various changes can be made and equivalents can be substituted without departing from the true spirit and scope of the application. In addition, many modifications can be made to adapt a particular situation to the teachings of the application without departing from the central inventive concept described herein. Accordingly, the application is not limited to only those embodiments described above, but instead has wide applicability to any device, system, and method that falls within the scope of the appended claims.

[0268] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. One skilled in the art will understand that the application can be practiced with embodiments that are not now considered to be the best implementations or preferred arrangements on the present application. Therefore, the application is not limited to the specific illustrative examples, and includes all alternatives affecting only the scope of the claims. It is therefore desired that what is claimed be what is literally disclosed by the above description.

[0269] Similarly, it is to be noticed that the term "comprising", used in the description, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, steps or components as referred to, but does not preclude the presence or addition of one or more other features, steps or components, or groups thereof. Thus, embodiments of the application have been described herein with reference to particular embodiments. However, other variations and modifications can be made to the described embodiments within the scope of the application. For example, the described embodiments can be applied to other types of devices, systems, and methods. Furthermore, where a range of values is provided, it is understood that every intervening value, between the upper and lower limit, is encompassed in the disclosure. Also, it is contemplated that any optional feature of the inventive variations described can be set forth or carried out separately or in any combination of the presently recited features. Accordingly, the application is not to be limited by what has been described in the specification.

[0270] In some embodiments, numbers that describe amounts, dimensions, and so forth, are used in the description of the embodiments. It should be understood that such numbers are used only to illustrate certain embodiments and that the application is not limited to the numbers. In some examples, the numbers are modified by the modifier "about" or "approximately." Unless otherwise indicated, "about" or "approximately" means ±20% of the value stated. Accordingly, in some embodiments, numerical parameters are approximations and can vary depending on the requirements of the particular embodiment. In some embodiments, numerical parameters are determined by the limitations inherent in the measurement systems used to determine the parameters. Although the numerical ranges and parameters setting forth the broad scope of the application in some embodiments 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 occur depending on the choice of the device used to carry out the described method.

[0271] Each patent, patent application, publication, and other material cited in this application is hereby incorporated by reference in its entirety. In the event of inconsistencies between the disclosure of this application and the disclosure of the cited material, the disclosure of this application shall prevail. To the extent the cited material contradicts or is inconsistent with this application, the cited material is hereby superseded by this application. It should be noted that, if descriptions, definitions, and / or terminology used in the cited material are inconsistent or conflict with the descriptions, definitions, and / or terminology used in this application, the descriptions, definitions, and / or terminology used in this application shall prevail.

[0272] Finally, it should be understood that the embodiments described herein are merely exemplary of the application. Other variations of the embodiments can be devised by those skilled in the art without departing from the scope of the present application. Accordingly, while the present application is depicted and described by reference to certain exemplary embodiments, it will be understood that the application is not limited to the examples described but is only limited by the claims.

Claims

1. A bone conduction sound transmission device, characterized in that, 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 base structure vibrates based on an external vibration signal, and the vibration unit deforms in response to the vibration of the base structure; the acoustic transducer generates an electrical signal based on the deformation of the vibration unit. The vibration unit includes at least two support arms and a mass element. One end of each support arm is connected to the base structure, and the other end is connected to the mass element. The mass element is connected to the base structure through the at least two support arms. The acoustic transducer unit includes an effective acoustic transducer unit, which is disposed on the support arm near the mass element, or near the connection between the support arm and the substrate structure. The connection points of each of the support arms and the mass element are arranged in a rotationally symmetrical manner about the center of the mass element, or the cross-section of the mass element perpendicular to the thickness direction is a polygon, and the number of support arms corresponds to the number of sides of the polygon.

2. The bone conduction sound transmission device according to claim 1, characterized in that, The resonant frequency of the bone conduction sound transmission device is 1kHz-5kHz.

3. The bone conduction sound transmission device according to claim 2, characterized in that, The resonant frequency of the bone conduction sound transmission device is 2.5kHz-4.5kHz.

4. The bone conduction sound transmission device according to claim 3, characterized in that, The resonant frequency of the bone conduction sound transmission device is 2.5KHz-3.5kHz.

5. The bone conduction sound transmission device according to claim 1, characterized in that, The resonant frequency of the bone conduction sound transmission device is positively correlated with the stiffness of the vibration unit.

6. The bone conduction sound transmission device according to claim 1, characterized in that, The resonant frequency of the bone conduction sound transmission device is negatively correlated with the mass of the stacked structure.

7. The bone conduction sound transmission device according to claim 1, characterized in that, The acoustic transducer unit includes a first electrode layer, a first piezoelectric layer and a second electrode layer arranged sequentially from top to bottom, and the first electrode layer or the second electrode layer is connected to the upper or lower surface of at least one support arm.

8. The bone conduction sound transmission device according to claim 7, characterized in that, The area of ​​the first electrode layer, the first piezoelectric layer, and / or the second electrode layer is not greater than the area of ​​the support arm, and the first electrode layer, the first piezoelectric layer, and / or the second electrode layer partially or completely covers the upper or lower surface of the at least one support arm.

9. The bone conduction sound transmission device according to claim 7, characterized in that, The acoustic transducer includes at least one elastic layer, which is located on the upper and / or lower surface of the first electrode layer or the second electrode layer.

10. The bone conduction sound transmission device according to claim 9, characterized in that, The acoustic transducer unit further includes a first seed layer, which is disposed between the elastic layer and the first electrode layer or between the elastic layer and the second electrode layer.

11. The bone conduction sound transmission device according to claim 7, characterized in that, A neutral layer is formed on the bone conduction sound transmission device, and the deformation stress of the neutral layer is zero when the support arm deforms; the neutral layer and the first piezoelectric layer do not coincide in the thickness direction.

12. The bone conduction sound transmission device according to claim 7, characterized in that, The thickness of the first electrode layer is 80nm-250nm, and / or the thickness of the second electrode layer is 80nm-250nm.

13. The bone conduction sound transmission device according to claim 7, characterized in that, The thickness of the first piezoelectric layer is 0.8μm-2μm.

14. The bone conduction sound transmission device according to claim 9, characterized in that, The thickness of the elastic layer is 1 to 6 times the thickness of the first piezoelectric layer.

15. The bone conduction sound transmission device according to claim 1, characterized in that, The thickness of the mass element is 1μm-400μm.

16. The bone conduction sound transmission device according to claim 1, characterized in that, The mass element comprises, from bottom to top, a base layer, a third electrode layer, a second piezoelectric layer, and a fourth electrode layer.

17. The bone conduction sound transmission device according to claim 1, characterized in that, The mass element comprises, from bottom to top, a base layer, a third electrode layer, a second piezoelectric layer, and a fourth electrode layer.

18. The bone conduction sound transmission device according to claim 17, characterized in that, The thickness of the substrate layer is 20μm-400μm.

19. The bone conduction sound transmission device according to claim 1, characterized in that, The ratio of the intensity of the electrical signal to the intensity of the noise in the bone conduction sound transmission device is 50%-100% of the maximum ratio of the electrical signal to the noise intensity.

20. The bone conduction sound transmission device according to claim 1, characterized in that, The acoustic transducer unit includes a first electrode layer, a first piezoelectric layer, and a second electrode layer. The ratio of the area of ​​the overlapping region of the first electrode layer, the first piezoelectric layer, and the second electrode layer to the area of ​​the cross section of the support arm perpendicular to the thickness direction is 5%-40%.

21. The bone conduction sound transmission device according to claim 7, characterized in that, An electrode insulating channel is provided on the first electrode layer or the second electrode layer, and the electrode insulating channel is used to divide the first electrode layer or the second electrode layer into two or more electrode regions.

22. The bone conduction sound transmission device according to claim 21, characterized in that, The width of the electrode insulation channel is less than or equal to 20 μm.

23. The bone conduction sound transmission device according to claim 1, characterized in that, The cross-section of the at least one support arm perpendicular to the thickness direction is polygonal.

24. The bone conduction sound transmission device according to claim 23, characterized in that, The side length of the polygon is 100~600μm.

25. The bone conduction sound transmission device according to claim 23, characterized in that, The cross-section of the at least one support arm perpendicular to the thickness direction is rectangular or trapezoidal.

26. The bone conduction sound transmission device according to claim 1, characterized in that, The cross-section of the mass element perpendicular to the thickness direction is a polygon, and the number of support arms corresponds to the number of sides of the polygon.

27. The bone conduction sound transmission device according to claim 25, characterized in that, When the cross-section of the support arm perpendicular to the thickness direction is rectangular, the length of the support arm is 100μm~500μm and the width of the support arm is 150μm~400μm.

28. The bone conduction sound transmission device according to claim 25, characterized in that, The cross-section of the support arm perpendicular to the thickness direction is trapezoidal; the height of the trapezoid is 150μm~600μm, the length of the long side of the trapezoid is 300μm~600μm, and the length of the short side of the trapezoid is 100μm~400μm.

29. The bone conduction sound transmission device according to claim 1, characterized in that, The support arm includes a first strip portion and a second strip portion; one end of the first strip portion is connected to the mass element, and the other end is connected to one end of the second strip portion; the other end of the second strip portion is connected to the base structure.

30. The bone conduction sound transmission device according to claim 29, characterized in that, The length of the first strip is 20μm to 200μm; the width of the first strip is 50μm to 400μm.

31. The bone conduction sound transmission device according to claim 29, characterized in that, The length of the second strip is 500μm to 1300μm; the width of the second strip is 50μm to 400μm.

32. The bone conduction sound transmission device according to claim 1, characterized in that, The support arm includes a first strip portion, a second strip portion, and a third strip portion; one end of the first strip portion is connected to the mass element, and the other end is connected to one end of the second strip portion; the other end of the second strip portion is connected to one end of the third strip portion; and the other end of the third strip portion is connected to the base structure.

33. The bone conduction sound transmission device according to claim 32, characterized in that, The length of the first strip is 20μm to 200μm; the width of the first strip is 50μm to 300μm.

34. The bone conduction sound transmission device according to claim 32, characterized in that, The length of the second strip is 500μm to 1200μm; the width of the second strip is 50μm to 300μm.

35. The bone conduction sound transmission device according to claim 32, characterized in that, The length of the third strip is 800μm to 1300μm; the width of the third strip is 50μm to 300μm.

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