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, the seed layer is located at 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 connection between the stack structure and the base structure.

[0011] In some embodiments, the vibration unit comprises at least one elastic layer, 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, 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, and the plurality of holes 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 100um-400um.

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

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

[0019] In some embodiments, the vibration unit further comprises a mass element, and the mass element 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 the 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 80nm-250nm, and / or the thickness of the second electrode layer is 80nm-250nm.

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

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

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

[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 3001um-400um.

[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 um.

[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 um.

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

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

[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 located 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 arranged 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 um.

[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 um, and the width of the support arm is 150 to 400 um.

[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 um, the length of the long side of the trapezoid is 300 to 600 um, and the length of the short side of the trapezoid is 100 to 400 um.

[0075] In some embodiments, the support arm comprises 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.

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

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

[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 50um-300um, and the length of the first strip-shaped portion is 20um-200um.

[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 50um-300um; and the length of the second strip-shaped portion is 800um-1300um.

[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 100um-400um; and the length of the first strip-shaped portion is 20um-200um.

[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 100um-400um; and the length of the second strip-shaped portion is 500um-1000um.

[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 thereof 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 body.

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

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

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

[0087] In some embodiments, the base body 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 structure or operation. It should be understood that the drawings are for the purpose of illustration and description only, and are not intended to limit the scope of the present application. It should be understood that the drawings are not drawn to scale.

[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 (for example, physical vapor deposition) or chemical deposition (for example, 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. Wherein, 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) 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) is negatively correlated with the resonance frequency f0on the system of the bone conduction sound transmission device. In some embodiments, is positively correlated with the resonance frequency f0on the system of the bone conduction sound transmission device. 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, and c 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 is usually very small, and the resonance frequency of the system is mainly affected by the equivalent stiffness and the equivalent mass. For example, 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 Figure 1 and Figure 2 shown, 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 prism as shown in the figures, and in some embodiments, the frame structure can be a regular or irregular structure such as a prism, a cylinder, etc. 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 cooperation. 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 in cooperation. Here, "connection" can be understood as, after the laminated structure and the base structure 110 are respectively prepared, the laminated structure and the base structure 110 are fixedly connected by welding, riveting, bonding, bolt connection, clamping, etc.; 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.More preferably, the area of ​​the piezoelectric layer 122 covering the first electrode layer 121 or the second electrode layer 123 is no greater than 1 / 4 of the area of ​​the first electrode layer 121 or the second electrode layer 123. In some embodiments, to prevent short circuits caused by the connection between the first electrode layer 121 and the second electrode layer 123, the area of ​​the first electrode layer 121 may 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., an 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 may have a certain distance from the edge of the piezoelectric layer 122, so that the first electrode layer 121 avoids the area of ​​poor material quality at the edge of the piezoelectric layer 122, thereby further improving the signal-to-noise ratio of the bone conduction sound transmission device 100.

[0152] In some embodiments, to increase the output electrical signal and improve the signal-to-noise ratio of the bone conduction sound transmission device 100, the piezoelectric layer 122 may 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 where the deformation stress is approximately zero during deformation. In some embodiments, the signal-to-noise ratio of the bone conduction sound transmission device 100 can also be improved by adjusting (e.g., increasing) the stress and stress variation gradient per unit thickness of the piezoelectric layer 122. In some embodiments, the signal-to-noise ratio and sensitivity of the bone conduction sound transmission device 100 can also be improved by adjusting the shape, thickness, material, and dimensions (e.g., length, width, and thickness) of the acoustic transducer unit 120 (e.g., the first electrode layer 121, the piezoelectric layer 122, and the second electrode layer 123) and the vibration unit 130 (e.g., the first elastic layer 131 and the second elastic layer 132).

[0153] In some embodiments, to control the warping deformation of the laminated structure, it is necessary to balance the stress in each layer of the laminated structure so that the stresses on the upper and lower parts of the neutral layer of the cantilever beam are of the same type (e.g., tensile stress, compressive stress) and equal in magnitude. For example, when the piezoelectric layer 122 is an AIN material layer, the piezoelectric layer 122 is disposed on one side of the neutral layer position of the cantilever beam. The AIN material layer is usually under tensile stress, and the combined stress of the elastic layer located on the other side of the neutral layer should also be 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 rectangle shown in the figure, but can also be a regular or irregular shape such as a triangle, a trapezoid, a circle, a semicircle, a quarter circle, an ellipse, a 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 Figure 1 shown in the figure, but the biggest difference is Figure 3 the shape of the stacked structure of the bone conduction sound transducing device 300. As Figure 3 shown, the bone conduction sound transducing device 300 includes a base structure 310 and a stacked structure, and the shape of the stacked structure is a trapezoid. Further, the width of the stacked structure in the bone conduction sound transducing device 300 tapers from the free end to the fixed end. In other embodiments, the width of the stacked structure in the bone conduction sound transducing device 300 can increase from the free end to the fixed end. It should be noted that the structure of the base structure 310 is similar to that of the base structure 110, and the structure of the vibration unit 330 is similar to that of the vibration unit 130. For details of each layer 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, please refer to Figure 1The contents of each layer of the acoustic transducing unit 120 and the vibration unit 130. In addition, other components (e.g., seed layers) in the acoustic transducing unit 120 and the vibration unit 130 are also applicable to Figure 3 The bone conduction sound transmission device 300 shown in FIG. 3 is not described here.

[0157] Figure 4 is a structural schematic diagram of a bone conduction sound transmission device according to another embodiment of the present application. As shown in FIG. 4, Figure 4 The bone conduction sound transmission device 400 can include a base structure 410 and a laminated structure, wherein at least part of the laminated structure is connected with the base structure 410. In some embodiments, the base structure 410 can be a hollow frame structure, and part of the laminated structure (e.g., the end of the laminated structure away from the connection between the laminated structure and the base structure 410) can be located in the hollow part of the frame structure. It should be noted that the frame structure is not limited to Figure 4 the cuboid shown in FIG. 3. 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 with 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 with the frame structure, and the free end of the laminated structure is not connected with or in contact with the frame structure, so that the free end of the laminated structure can be suspended in the hollow part of the frame structure. In some embodiments, the fixed end of the laminated structure can be connected with the upper surface, the lower surface of the base structure 410, or the side wall where the hollow part of the base structure 410 is located. In some embodiments, the side wall where the hollow part of the base structure 410 is located can also be provided with a mounting groove matched with the fixed end of the laminated structure, so that the fixed end of the laminated structure is connected with the base structure 410. Here, "connection" can be understood as fixing the laminated structure and the base structure 410 by welding, riveting, clamping, bolting, etc. after the laminated structure and the base structure 410 are respectively prepared. In some embodiments, the laminated structure can also be deposited on the base structure 410 by physical deposition (e.g., physical vapor deposition) or chemical deposition (e.g., chemical vapor deposition) during the preparation process. In some embodiments, one or more laminated structures can be provided on the base structure 410, for example, the number of laminated structures can be 1, 2, 3, 7, etc. Further, the plurality of laminated structures can be arranged equidistantly and uniformly along the circumference of the base structure 410, or can be arranged non-uniformly.

[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 a piezoelectric ceramic material, and when the piezoelectric layer 423 is a piezoelectric ceramic material, the polarization direction of the piezoelectric layer 423 is consistent with the length direction of the cantilever beam, and the piezoelectric constant d of the piezoelectric ceramic is utilized. 33 The piezoelectric constant d refers to the proportional constant of the piezoelectric layer 323 converting mechanical energy into electrical energy. It should be noted that, 33 The piezoelectric constant d refers to the proportional constant of the piezoelectric layer 323 converting mechanical energy into electrical energy. It should be noted that, Figure 4 The piezoelectric layer 423 shown in FIG. 4 can also be other materials, and when the polarization direction of the piezoelectric layer 423 of other materials is consistent with the thickness direction of the cantilever beam, the acoustic transducing unit 420 can be replaced by Figure 1 The acoustic transducing unit 120 shown in FIG. 1.

[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 film-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, and will not be further limited here.

[0165] In combination Figure 5 and Figure 6In some embodiments, the acoustic transducing unit 520 can include a first electrode layer 521, a piezoelectric layer 522, and a second electrode layer 523 arranged in order from top to bottom, where the positions of the first electrode layer 521 and the second electrode layer 523 can be interchanged. The piezoelectric layer 522 can generate a voltage (potential difference) based on 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 obtained by a solid phase reaction and sintering between different material powders and a random collection of microcrystalline grains. 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 are made of a conductive material structure. Exemplary conductive materials can include metals, alloy materials, metal oxide materials, graphene, etc., or any combination thereof. In some embodiments, the metals and alloy materials can include nickel, iron, lead, platinum, titanium, copper, molybdenum, zinc, etc., or any combination thereof. In some embodiments, the alloy material 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 signals 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 um-400 um. 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 um-300 um. 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 um-250 um.

[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 surrounded by the plurality of holes 5300 is not limited to Figure 5 the circle shown, but can also be a semicircle, a quarter circle, an ellipse, a semicircle, a triangle, a rectangle, or other regular or irregular shapes. The shape of the acoustic transducing unit 520 can be adaptively adjusted according to the shape of the area surrounded by the plurality of holes 5300. For example, when the shape of the area surrounded by the plurality of holes 5300 is a rectangle, the shape of the acoustic transducing unit 520 can be a rectangle, and the acoustic transducing unit 520 in the shape of a rectangle can be distributed along the inner side or the outer side of the rectangle surrounded by the plurality of holes 5300. For another example, when the shape of the area surrounded by the plurality of holes 5300 is a semicircle, the shape of the acoustic transducing unit 520 can be a semicircle, and the acoustic transducing unit 520 in the shape of a semicircle can be distributed along the inner side or the outer side of the rectangle surrounded by the plurality of holes 5300. In some embodiments, Figure 5 holes can not be opened on the suspended membrane structure 530 in the acoustic transducing unit 520 in

[0170] Figure 7 is a structural schematic diagram of a bone conduction sound transducing device according to some embodiments of the present application. Figure 7 The bone conduction sound transducing device 700 shown is substantially the same in structure as the bone conduction sound transducing device 500 shown in Figure 5 The bone conduction sound transducing device 700 shown is substantially the same in structure as the bone conduction sound transducing device 500 shown in Figure 7 The vibration unit of the bone conduction sound transducing device 700 shown includes a suspended membrane structure 730 and a mass element 740.

[0171] As shown in Figure 7 The bone conduction sound transducing device 700 can include a base structure 710 and a laminated structure, and at least part of the laminated structure is connected to the base structure 710. In some embodiments, the base structure 710 can be a frame structure with an internal cavity, and part of the laminated structure can be located in the cavity of the frame structure. It should be noted that the frame structure is not limited to Figure 7 the cuboid shown in

[0172] In some embodiments, the laminated structure can include an acoustic transducing unit 720 and a vibration unit. In some embodiments, the vibration unit can be arranged on the upper surface or the lower surface of the acoustic transducing unit 720. As shown in 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 of the base structure 710 or the 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 transmission 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 transmission 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 vibrating 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 100µm to 500µm. In some embodiments, the length X of the support arm 830 is 150µm to 350µm. In some embodiments, the width Y of the support arm 830 is 150µm to 400µm. In some embodiments, the width Y of the support arm 830 is 250µm to 350µm. 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, 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 (potential difference) based on the piezoelectric effect under the deformation stress of the vibration unit (e.g., the support arm 830 and the mass element 840), and the first electrode layer 821 and the second electrode layer 823 can guide the voltage (electric signal) out. In order to make the resonance frequency of the bone conduction sound transmission device 800 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.

[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 0.8um-2um. In some embodiments, the thickness of the first piezoelectric layer 822 is 0.8um-1.5um. 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, so that the acoustic transducing unit 820 can generate a larger electric 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 substrate material from being damaged in the subsequent etching process. 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 um, and in some embodiments, the thickness of the etching stop layer can be 300 nm-1 um.

[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, when 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 when 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 um. In some embodiments, the thickness of the elastic layer 824 is 2-6 um. 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 out from the first electrode layer 821 or the second electrode layer 823 on 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 front view of a bone conduction sound transmission device 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 does not coincide with the neutral layer 831, 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 um-400 um. In some embodiments, the thickness of the substrate layer can be 300 um-400 um. In some embodiments, the thickness of the substrate layer can be 200 um-300 um.

[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 um-1200 um. In some embodiments, the length of at least one side of the rectangle can be 750 um-1050 um.

[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 greater 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

[0202]

[0203] wherein v s is the sensitivity of the bone conduction sound transmission device. v s is positively correlated with the piezoelectric constant and the internal stress of the piezoelectric layer (such as the first piezoelectric layer 822), wherein the piezoelectric constant is related to the material of the piezoelectric layer, and the internal stress of the piezoelectric layer is related to the structure of the bone conduction sound transmission device and the external load. In some embodiments, the sensitivity value v s of the structure of the bone conduction sound transmission device under the corresponding external load can be solved by means of finite element numerical calculation method after the model is established. v ntrms is the noise floor of the bone conduction sound transmission device, and the noise floor v ntrms of the bone conduction sound transmission device can be determined by parameters such as the noise floor value v narms of the amplification circuit (ASIC) and the noise floor value v nsrms of the transducer (acoustic transducing unit). The noise floor v ntrms of the bone conduction sound transmission device is positively correlated with the noise floor value v narms of the amplification circuit (ASIC) and the noise floor value v nsrms of the transducer. v narms is the noise floor value of the amplification circuit (ASIC), which can be calculated during the design process of the amplification circuit or obtained from the manufacturer. In some embodiments, the noise floor vntrms may be related to Boltzmann constant κ B , Fahrenheit temperature T, electrostatic force constant k, dielectric loss tan δ of the piezoelectric layer (such as the first piezoelectric layer 822), dielectric constant ε r of the piezoelectric layer (such as the first piezoelectric layer 822), thickness d of the piezoelectric layer (such as 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, and the like.

[0204] In some embodiments, the background noise v ntrms of the bone conduction sound device may be positively related to Boltzmann constant κ B , Fahrenheit temperature T, electrostatic force constant k, dielectric constant ε r of the piezoelectric layer (such as the first piezoelectric layer 822), thickness d of the piezoelectric layer (such as 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 may 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 (such as the first piezoelectric layer 822). In some embodiments, the background noise v ntrms of the bone conduction sound device may 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 (such as the first piezoelectric layer 822), ε r is the dielectric constant of the piezoelectric layer (such as the first piezoelectric layer 822), d is the thickness of the piezoelectric layer (such as 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]

[0209] The meanings of the parameters in formula (3) are explained above. In formula (3) above, the dielectric loss tan d of the piezoelectric material, the dielectric constant e 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 (which 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 meanings of the parameters in formula (3) are explained above. In formula (3) above, the dielectric loss tan d of the piezoelectric material, the dielectric constant e 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 (which 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.

[0210] According to the formula for calculating the signal-to-noise ratio (SNR) of the bone conduction sound transducing device proposed in this patent, the materials of the electrode layers (the first electrode layer 821 and the second electrode layer 823), the piezoelectric layers (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 maximizing the signal-to-noise ratio (SNR) of the bone conduction sound transducing device. For example, the structure of the support arm plus the mass element (or the structure of the cantilever beam, the structure of the perforated suspension membrane, the structure of the suspension membrane plus the mass element, etc.) is designed, and the sizes 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 materials, sizes, and the like of the parts of the acoustic transducing unit 820, the support arm 830, and the mass element 840 can be designed to adjust the stiffness of the support arm 830 and the mass of the mass element 840 to cause stress concentration 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 the 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 maximum SNR, for example, the designed SNR is 80%-100% of the maximum SNR; the designed SNR is 50%-100% of the maximum SNR; the designed SNR is 20%-100% of the maximum SNR.

[0211] 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.

[0212] 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.

[0213] 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.

[0214] 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 leading out the electrical signal can be made 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.

[0215] 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 As shown in the electrode insulation channel 850, the electrode insulation channel 850 can only separate the acoustic transducing unit 820 into multiple parts, and is not limited further.

[0216] As shown in the electrode insulation channel 850, the electrode insulation channel 850 can only separate the acoustic transducing unit 820 into multiple parts, and is not limited further. Figure 14 As shown in the electrode insulation channel 850, the electrode insulation channel 850 can only separate the acoustic transducing unit 820 into multiple parts, and is not limited further. 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 part of the first electrode layer 821 close to the connection between the support arm 830 and the base structure 810 can be separated by the electrode insulating channel 850 to form a partial area Figure 14 The first electrode layer 821 shown in the middle is located at the edge area 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 um. In some embodiments, the width L1 of the electrode lead 860 can be 4 um-20 um. In some embodiments, the width L1 of the electrode lead 860 can be 4 um-10 um. 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.

[0217] 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.

[0218] Considering that the piezoelectric material of the first piezoelectric layer 822 may become rough due to etching near the edge of the support arm 830, resulting in a deterioration in the quality of the piezoelectric material, 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 place the first electrode layer 821 in a region of better quality piezoelectric material, the area of ​​the first electrode layer 821 can be smaller than the area of ​​the first piezoelectric layer 822, so that the edge region of the first electrode layer 821 avoids the edge region of the first piezoelectric layer 822. An electrode recessed channel 870 can be formed between the first electrode layer 821 and the first piezoelectric layer 822 (e.g., Figure 15 (As shown). By providing the electrode recessed channel 870, the region with poor edge quality of the first piezoelectric layer 822 can be avoided from the first electrode layer 821 and the second electrode layer 823, thereby improving the signal-to-noise ratio of the output bone conduction sound transmission device 800. In some embodiments, the width of the electrode recessed channel 870 can be 2µm-20µm. In some embodiments, the width of the electrode recessed channel 870 can be 2µm-10µm.

[0219] In some embodiments, an electrode recessed channel 870 is formed at the edge of the first piezoelectric layer 822. A first electrode layer 821 is located 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 μm. In some preferred embodiments, the width of the electrode recessed channel 870 can be 2-10 μm. The width design of the electrode recessed channel 870 facilitates the planning of the electrode area on the support arm 830 and also facilitates the processing of the electrode recessed channel 870.

[0220] In some embodiments, the bone conduction sound transmission device 800 may simultaneously include the electrode insulating channel 850, electrode lead 860, and electrode recessed channel 870 structures described in one or more embodiments of this specification. The electrode insulating channel 850, electrode lead 860, and electrode recessed channel 870 can be fabricated by etching. For example, etching can be performed sequentially 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 be performed using dry etching or wet etching. When an elastic layer 824 is provided, the elastic layer 824 can be further etched. In some embodiments, after the electrode insulating channel 850, electrode lead 860, and electrode recessed channel 870 have all been etched, a wire-binding electrode layer 826 can be disposed on the first electrode layer 821.

[0221] like 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 4-30um. In some embodiments, the length of the extension region 8210 is 4-15um. 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 connection between the support arm 830 and 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 connection between the support arm 830 and 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 connection between the support arm 830 and the edge of the mass element 840.

[0222] 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.

[0223] In some embodiments, the height of the trapezoid is greater than the length of the short side of the trapezoid (e.g., the height of the trapezoid is greater than the length of the short side of the trapezoid by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or more). Figure 17The height h) of the trapezoid is 150-600 um. In some embodiments, the height of the trapezoid is 200-500 um. In some embodiments, the length of the long side of the trapezoid is 300-600 um. In some embodiments, the length of the long side of the trapezoid is 350-550 um. In some embodiments, the length of the short side of the trapezoid is 100-400 um. In some embodiments, the length of the short side of the trapezoid is 150-300 um. In some embodiments, the length of the short side of the trapezoid is 150-250 um. 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 rigidity of the support arm 1730 can be adjusted, thereby adjusting the resonant frequency of the bone conduction sound transmission device 1700.

[0224] 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.

[0225] 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. 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%-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%-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%-20%.

[0226] 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 in 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 in 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 2um-20um. In some embodiments, the width of the electrode insulation channel 1750 can be 4um-10um.

[0227] 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

[0228] 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 4um-20um. In some embodiments, the width L2 of the electrode lead 1760 can be 4um-10um. 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 of the support arm 1730 or close to the edge in the width direction. 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.

[0229] 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 be 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 middle electrode insulating channel 1750, 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 2um-20um. In some embodiments, the width 11212 of the electrode recessed channel can be 2um-10um.

[0230] 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 4um-30um. In some embodiments, the width of the extension region 17210 is 4um-15um. In some embodiments, the width of the extension region 17210 on the mass element 1740 is 1.2 to 2 times the width of the connection between the support arm 1730 and the edge of the mass element 1740. In some embodiments, the width of the extension region 17210 on the mass element 1740 is 1.2 to 1.5 times the width of the connection between the support arm 1730 and the edge of 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.

[0231] 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 It is based on Figure 21 A front view of the bone conduction sound transmission device shown. Figure 21-22 The bone conduction sound transmission device 2100 shown is... Figure 8 The bone conduction sound transmission devices 800 shown are largely the same in structure, differing only in the shape of the support arm. For example... Figure 21 As shown, the base structure 2110 is a cuboid frame structure. In some embodiments, the interior of the base structure 2110 may include a hollow portion for suspending the acoustic transducer and the vibration unit. In some embodiments, the vibration unit may include four support arms 2130 and a mass element 2140. One end of the four support arms 2130 is connected to the upper surface, lower surface, or sidewall of the hollow portion of the base structure 2110, and the other end of the four support arms 2130 is connected to the upper surface, lower surface, or circumferential sidewall of the mass element 2140. In some embodiments, the mass element 2140 may protrude upward and / or downward relative to the support arms 2130. For example, when the ends of the four support arms 2130 are connected to the upper surface of the mass element 2140, the mass element 2140 may protrude downward relative to the support arms 2130. For example, when the ends of the four support arms 2130 are connected to the lower surface of the mass element 2140, the mass element 2140 may protrude upward relative to the support arms 2130. As another example, when the ends of the four support arms 2130 are connected to the circumferential sidewalls of the mass element 2140, the mass element 2140 may protrude upward and downward relative to the support arms 2130. In some embodiments, the support arm 2130 is trapezoidal in shape, that is, the cross-section of the support arm 2130 perpendicular to the thickness direction is trapezoidal. The longer end of the support arm 2130 (the long side of the trapezoid) is connected to the mass element 2140, and the shorter end of the support arm 2130 (the short side of the trapezoid) is connected to the base structure 2110. In other embodiments, the shorter end of the support arm 2130 (the short side of the trapezoid) is connected to the mass element 2140, and the longer end of the support arm 2130 (the long side of the trapezoid) is connected to the base structure 2110. It should be noted that, Figure 8- Figure 10 The structure, dimensions, thickness, and other parameters of components such as the acoustic transducer 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 region 8210, the electrode insulation communication 850, the electrode lead 860, and the electrode recessed channel 870 can be applied to the bone conduction sound transmission device 2100, and will not be further elaborated here.

[0232] 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.

[0233] 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.

[0234] 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.

[0235] 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.

[0236] 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 24) In some embodiments, the width N1 of the first strip portion 2331 is 50-300um. In some embodiments, the width N1 of the first strip portion 2331 is 80-200um. In some embodiments, the width N2 of the second strip portion 2332 is 50-300um. In some embodiments, the width N2 of the second strip portion 2332 is 80-200um. In some embodiments, the length L1 of the first strip portion 2331 is 20-200um. In some embodiments, the length L1 of the first strip portion 2331 is 30-100um. In some embodiments, the length L2 of the second strip portion 2332 is 800-1300um. In some embodiments, the length L2 of the second strip portion 2332 is 900-1200um.

[0237] 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).

[0238] 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 non-end position 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".

[0239] 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 Figure 24 The difference between the embodiments shown 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 100-400um. In some embodiments, the width N3 of the first bar-shaped portion 2331 is 150-300um. In some embodiments, the width N4 of the second bar-shaped portion 2332 is 100-400um. In some embodiments, the width N4 of the second bar-shaped portion 2332 is 150-300um. In some embodiments, the length L3 of the first bar-shaped portion 2331 is 20-200um. In some embodiments, the length L3 of the first bar-shaped portion 2331 is 30-100um. In some embodiments, the length L4 of the second bar-shaped portion 2332 is 500-1000um. In some embodiments, the length L4 of the second bar-shaped portion 2332 is 700-900um.

[0240] 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 a rectangle, 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.

[0241] 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 extension region 2380 when the support arm 2330 includes two bar-shaped portions. As 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 channel 2350, an electrode lead 2360, an electrode indentation channel 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 channel 850, the electrode lead 860, the electrode indentation channel 870, etc. in the description of the bone conduction sound transducing device 3100 in the present application. 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 channel 850, the electrode lead 860, the electrode indentation channel 870, etc. can be described as in the description of the bone conduction sound transducing device 3100 in the present application. Figure 23 As shown, the bone conduction sound transducing device 2300 is not further described herein.

[0242] 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 in 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. 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 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.

[0243] 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 in Figure 31As shown, the connection of the first bar 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 3131 can be 50um-300um. In some embodiments, the width N5 of the first bar 3131 is 80um-150um. In some embodiments, the width N6 of the second bar 3132 can be 50um-300um. In some embodiments, the width N6 of the second bar 3132 is 80um-150um. In some embodiments, the width N7 of the third bar 3133 can each be 50um-300um. In some embodiments, the width N7 of the third bar 3133 is 80um-150um. In some embodiments, the length L5 of the first bar 3131 can be 20um-200um. In some embodiments, the length L5 of the first bar 3131 is 30um-100um. In some embodiments, the length L6 of the second bar 3132 is 600um-1200um. In some embodiments, the length L6 of the second bar 3132 is 800um-1000um. In some embodiments, the length L7 of the third bar 3133 can be 800um-1300um. In some embodiments, the length L7 of the third bar 3133 is 900um-1200um.

[0244] Figure 32 is a structural schematic diagram of a bone conduction microphone 3100 according to yet some embodiments of the present application. As shown, the bone conduction microphone 3100 includes a mass element 3140, a first bar 3131, a second bar 3132, and a third bar 3133. The first bar 3131 is connected to the mass element 3140 at a first end 3134 of the first bar 3131. The second bar 3132 is connected to the mass element 3140 at a second end 3135 of the second bar 3132. The third bar 3133 is connected to the mass element 3140 at a third end 3136 of the third bar 3133. The first bar 3131 is connected to the second bar 3132 at a first end 3137 of the second bar 3132. The second bar 3132 is connected to the third bar 3133 at a second end 3138 of the third bar 3133. The first bar 3131 is connected to the third bar 3133 at a third end 3139 of the third bar 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 um. In some embodiments, the width N8 of the first bar-shaped part 3131 is 80-150 um. In some embodiments, the width N9 of the second bar-shaped part 3132 is 50-300 um. In some embodiments, the width N9 of the second bar-shaped part 3132 is 80-150 um. In some embodiments, the width N10 of the third bar-shaped part 3133 is 50-300 um. In some embodiments, the width N10 of the third bar-shaped part 3133 is 80-150 um. In some embodiments, the length L8 of the first bar-shaped part 3131 is 20-200 um. In some embodiments, the length L8 of the first bar-shaped part 3131 is 30-100 um. In some embodiments, the length L9 of the second bar-shaped part 3132 is 500-1000 um. In some embodiments, the length L9 of the second bar-shaped part 3132 is 600-800 um. In some embodiments, the length L10 of the third bar-shaped part 3133 is 800-1300 um. In some embodiments, the length L10 of the third bar-shaped part 3133 is 900-1200 um.

[0245] 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.

[0246] 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.

[0247] 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, the 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.

[0248] In some embodiments, the thickness sum 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 thickness sum of the support arm and the acoustic transducing unit can be the sum of the thicknesses of the two. When the acoustic transducing unit is disposed inside the support arm, the thickness sum 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 greater, and thus the thickness of the mass element can be correspondingly set to be thicker, so that the mass of the mass element is greater, 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 thickness sum 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 greater 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.

[0249] 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).

[0250] 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.

[0251] The displacement output formula for the stacked structure is as follows:

[0252]

[0253] 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.

[0254] 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:

[0255]

[0256] 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.

[0257] The laminated structure loss factor η is related to the damping material loss factor tanδ as follows:

[0258]

[0259] 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.

[0260] From formula (5) and formula (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 damping structure layer can be increased to ensure that the sensitivity of the bone conduction sound transmission device in the non-resonance region is not reduced, while the Q value in the resonance region is reduced, 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.

[0261] 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.

[0262] 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 , and the bone conduction microphone device 400 as shown in Figure 4 ) is taken as an example for illustrative description. 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.

[0263] 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 sound transmission device 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 the upper surface of the base structure 3710, and the lower surface of the laminated structure 3720 is connected to the upper surface of the second damping structure layer 3730, wherein one end of the laminated structure 3720 is suspended in the hollow portion of the base structure 3710, and the first damping structure layer 3730 is located on the 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.

[0264] Figure 38 FIG. 38 is a cross-sectional view of a bone conduction sound transmission device according to some embodiments of the present disclosure. As shown in FIG. 38, the bone conduction sound transmission device 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 the upper surface of the base structure 3810. The lower surface of the laminated structure 3820 is connected to the upper surface of the damping structure layer 3830, and one end of the laminated structure 3820 is suspended in the hollow portion of the base structure 3810. Figure 38

[0265] It should be noted that the position of the damping structure layer (for example, 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 multiple layers 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 sound transmission device as described above, but can also be applied to the bone conduction sound transmission devices as shown in FIGS. 39-45, which will not be described herein. Figure 36- Figure 38 Figure 5 Figure 7 Figure 8 Figure 17 Figure 21 Figure 23 Figure 31

[0266] The foregoing merely illustrates the principles of the application. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the application and are thus within its spirit and scope. It will be understood that the above description is merely illustrative of the principles of the application and that numerous modifications, both as to the details of structures and the product itself, can be made by those skilled in the art without departing from the spirit and scope of the application as described herein.

[0267] ​​​​​​​​​Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0268] Furthermore, those skilled in the art will understand that aspects of this application can be described and illustrated through several patentable types or situations, including any new and useful combination of processes, machines, products, or substances, or any new and useful improvements thereof. Accordingly, aspects of this application can be implemented entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. All of the above hardware or software may be referred to as a “data block,” “module,” “engine,” “unit,” “component,” or “system.” Furthermore, aspects of this application may manifest as a computer product located on one or more computer-readable media, the product including computer-readable program code.

[0269] Furthermore, unless expressly stated in the claims, the order of processing elements and sequences, the use of numbers and letters, or other names described in this application are not intended to limit the order of the processes and methods of this application. Although various examples have been discussed in the foregoing disclosure of some embodiments that are currently considered useful, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments. Rather, the claims are intended to cover all modifications and equivalent combinations that conform to the substance and scope of the embodiments of this application. For example, while the system components described above can be implemented by hardware devices, they can also be implemented solely by software solutions, such as installing the described system on existing processing devices or mobile devices.

[0270] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0271] 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, such numbers are modified by the modifier "about" or "approximately." Unless otherwise specified, "about" or "approximately" means ±20% of the value of the measured quantity that the term describes. Accordingly, in some embodiments, the numerical parameters in the description and claims are approximations that can vary depending upon the desired properties sought to be obtained by the individual embodiments. In some embodiments, numerical parameters are determined by the use of standard techniques. Although the numerical ranges and parameters setting forth the broad scope of the application are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values set forth in the specific examples are provided to be as precise as reasonably possible. However, some variations may occur depending on the choice of input used to develop or derive the numerical values in the examples.

[0272] Each patent, patent application, publication, document, article, book, instruction manual, and / or 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 materials incorporated by reference, the disclosure of this application shall prevail. The citation of any document, publication, article, book, instruction manual, and / or other material shall not be construed as an admission that such document, publication, article, book, instruction manual, and / or other material is prior art with respect to this application.

[0273] Finally, it should be understood that the embodiments described herein are merely illustrative of the principles of this application. Numerous modifications and adaptations will be readily apparent to those skilled in the art. Accordingly, the scope of this application is not limited to the embodiments described herein, but rather is defined by the following claims.

Claims

1. A bone conduction sound transmission device, characterized by, include: The base structure, including a hollow frame structure; A stacked structure includes a vibration unit and an acoustic transducer unit. The vibration unit includes a mass element and a plurality of support arms surrounding the mass element. The mass element is suspended in the hollow part of the base structure by the plurality of support arms. In the direction in which the plurality of support arms surround the mass element, the connection between each support arm and the base structure is located on the same side of the connection between the same support arm and the mass element. 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 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 surface or the lower surface of the support arm. An electrode insulating channel is provided on the first electrode layer or the second electrode layer. The electrode insulating channel is used to divide the first electrode layer or the second electrode layer into two or more electrode regions. At least one of the electrode regions is close to the mass element, and at least one of the electrode regions is close to the connection between the support arm and the substrate structure. When the acoustic transducer is disposed on the upper surface of the support arm, the electrode insulation channel is disposed on the first electrode layer; when the acoustic transducer is disposed on the lower surface of the support arm, the electrode insulation channel is disposed on the second electrode layer.

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 by 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 is located on the upper surface, lower surface, or inside the support arm.

8. The bone conduction sound transmission device according to claim 1, characterized in that, The mass element is located on the upper or lower surface of the first electrode layer or the second electrode layer.

9. The bone conduction sound transmission device according to claim 1, 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 support arm.

10. The bone conduction sound transmission device according to claim 1, characterized in that, 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.

11. The bone conduction sound transmission device according to claim 1, characterized in that, The first electrode layer, the first piezoelectric layer, and the second electrode layer of the acoustic transducer are located at one end of the connection between the support arm and the mass element and / or at one end of the connection between the support arm and the substrate structure.

12. The bone conduction sound transmission device according to claim 1, 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.

13. The bone conduction sound transmission device according to claim 12, 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.

14. The bone conduction sound transmission device according to claim 12, characterized in that, The acoustic transducer unit further includes at least one wire-binding electrode layer, which is disposed on the substrate structure and is used to extract electrical signals from the substrate structure.

15. The bone conduction sound transmission device according to claim 1, 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.

16. The bone conduction sound transmission device according to claim 1, 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.

17. The bone conduction sound transmission device according to claim 1, characterized in that, The thickness of the first piezoelectric layer is 0.8um-2um.

18. The bone conduction sound transmission device according to claim 12, characterized in that, The thickness of the elastic layer is 0.5um-10um.

19. The bone conduction sound transmission device according to claim 13, characterized in that, The thickness of the first seed layer is 10nm-120nm.

20. The bone conduction sound transmission device according to claim 12, characterized in that, The thickness of the elastic layer is 1 to 6 times the thickness of the first piezoelectric layer.

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

22. 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.

23. The bone conduction sound transmission device according to claim 22, characterized in that, The mass element also includes a second seed layer disposed between the substrate layer and the third electrode layer.

24. The bone conduction sound transmission device according to claim 22, characterized in that, The thickness of the substrate layer is 20um-400um.

25. 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.

26. 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%.

27. The bone conduction sound transmission device according to claim 1, characterized in that, The width of the electrode insulation channel is less than or equal to 20 μm.

28. The bone conduction sound transmission device according to claim 1, characterized in that, The first electrode layer or the second electrode layer has electrode leads for connecting the electrode region to the substrate.

29. The bone conduction sound transmission device according to claim 28, characterized in that, The width of the electrode lead is less than or equal to 20 μm.

30. The bone conduction sound transmission device according to claim 1, characterized in that, The overlapping area of ​​the first electrode layer, the first piezoelectric layer, and the second electrode layer extends toward the mass element to form an extended region, which is located on the upper or lower surface of the mass element.

31. The bone conduction sound transmission device according to claim 30, characterized in that, The width of the extended region in the plane perpendicular to the thickness direction is 1.2 to 2 times the width of the connection between the support arm and the mass element in the plane perpendicular to the thickness direction.

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

33. The bone conduction sound transmission device according to claim 32, characterized in that, The side length of the polygon is 100 to 600 μm.

34. The bone conduction sound transmission device according to claim 32, characterized in that, The cross-section of the support arm perpendicular to the thickness direction is rectangular or trapezoidal.

35. 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.

36. The bone conduction sound transmission device according to claim 34, 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 100um to 500um, and the width of the support arm is 150um to 400um.

37. The bone conduction sound transmission device according to claim 34, characterized in that, The cross-section of the support arm perpendicular to the thickness direction is trapezoidal; the height of the trapezoid is 150um to 600um, the length of the long side of the trapezoid is 300um to 600um, and the length of the short side of the trapezoid is 100um to 400um.

38. 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; wherein the included angle between the first strip portion and the second strip portion is in the range of 75°-105°.

39. The bone conduction sound transmission device according to claim 38, characterized in that, The length of the first strip portion is 20um to 200um; the length and width of the first strip portion are 50um to 400um.

40. The bone conduction sound transmission device according to claim 38, characterized in that, The length of the second strip is 500um to 1300um; the length of the second strip is 50um to 400um.

41. The bone conduction sound transmission device according to claim 39, characterized in that, When the connection between the first strip and the mass element is located at the end of the side of the mass element; the width of the first strip is 50um to 300um, and the length of the first strip is 20um to 200um.

42. The bone conduction sound transmission device according to claim 40, characterized in that, When the connection between the first strip and the mass element is located at the end of the side of the mass element; the width of the second strip is 50um to 300um; the length of the second strip is 800um to 1300um.

43. The bone conduction sound transmission device according to claim 39, characterized in that, When the connection between the first strip and the mass element is located at the midpoint of the side of the mass element; the width of the first strip is 100um to 400um; the length of the first strip is 20um to 200um.

44. The bone conduction sound transmission device according to claim 40, characterized in that, When the connection between the first strip and the mass element is located at the midpoint of the side of the mass element; the width of the second strip is 100um to 400um; the length of the second strip is 500um to 1000um.

45. The bone conduction sound transmission device according to claim 38, characterized in that, The mass element has a rectangular cross-section perpendicular to its thickness direction, and the first strip portion is perpendicular to the second strip portion.

46. ​​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.

47. The bone conduction sound transmission device according to claim 46, characterized in that, The length of the first strip portion is 20um to 200um; the length and width of the first strip portion are 50um to 300um.

48. The bone conduction sound transmission device according to claim 46, characterized in that, The length of the second strip is 500um to 1200um; the length of the second strip is 50um to 300um.

49. The bone conduction sound transmission device according to claim 46, characterized in that, The length of the third strip is 800um to 1300um; the width of the third strip is 50um to 300um.

50. The bone conduction sound transmission device according to claim 47, characterized in that, When the connection between the first strip and the mass element is located at the end of the side of the mass element, the width of the first strip is 50µm to 300µm; the length of the first strip is 20µm to 200µm.

51. The bone conduction sound transmission device according to claim 48, characterized in that, When the connection between the first strip and the mass element is located at the end of the side of the mass element, the width of the second strip is 50um to 300um; the length of the second strip is 600um to 1200um.

52. The bone conduction sound transmission device according to claim 49, characterized in that, When the connection between the first strip and the mass element is located at the end of the side of the mass element, the width of the third strip is 50um to 300um; the length of the third strip is 800um to 1300um.

53. The bone conduction sound transmission device according to claim 47, characterized in that, When the connection between the first strip and the mass element is located at the midpoint of the side of the mass element, the width of the first strip is 50µm to 300µm; the length of the first strip is 20µm to 200µm.

54. The bone conduction sound transmission device according to claim 48, characterized in that, When the connection between the first strip and the mass element is located at the midpoint of the side of the mass element, the width of the second strip is 50µm to 300µm; the length of the second strip is 500µm to 1000µm.

55. The bone conduction sound transmission device according to claim 49, characterized in that, When the connection between the first strip and the mass element is located at the midpoint of the side of the mass element, the width of the third strip is 50um to 300um; the length of the third strip is 800um to 1300um.

56. The bone conduction sound transmission device according to claim 46, characterized in that, The mass element has a rectangular cross-section perpendicular to its thickness direction, the second strip portion is perpendicular to the first strip portion, and the second strip portion is perpendicular to the third strip portion.

57. The bone conduction sound transmission device according to claim 1, characterized in that, The shape of the mass element corresponds to the shape of the cavity of the substrate structure.

58. The bone conduction sound transmission device according to claim 1, characterized in that, The combined thickness of the support arm and the acoustic transducer is less than the thickness of the mass element.

59. The bone conduction sound transmission device according to claim 1, characterized in that, The total thickness of the support arm and the acoustic transducer unit is greater than or equal to the thickness of the mass element.

60. The bone conduction sound transmission device according to claim 1, characterized in that, It also includes a limiting structure located within the cavity of the base structure, wherein the limiting structure is connected to the base structure and is located above and / or below the mass element.

61. The bone conduction sound transmission device according to claim 1, characterized in that, It also includes at least one damping layer, which covers the upper surface, lower surface and / or interior of the laminated structure.

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