Bone conduction sound transmission device

Abstract

The bone conduction acoustic transmission device of the present application includes a laminated structure formed of a vibration unit and an acoustic conversion unit, and a base structure configured to support the laminated structure and physically connected to at least one side of the laminated structure, wherein the base structure vibrates in response to an external vibration signal, the vibration unit deforms in response to the vibration of the base structure, and the acoustic conversion unit generates an electrical signal based on the deformation of the vibration unit.

Description

Technical Field

[0001] The present application relates to the technical field of acoustic transmission devices, and more particularly to bone conduction acoustic transmission devices.

Background Art

[0002] A microphone receives an external vibration signal, converts the vibration signal into an electrical signal using an acoustic conversion unit, and outputs the electrical signal after processing by a backend circuit. What an air conduction microphone receives is an air conduction voice signal, and the voice signal propagates through air. That is, an air conduction microphone receives an air vibration signal. What a bone conduction microphone receives is a bone conduction voice signal, and the voice signal propagates through a human bone. That is, a bone conduction microphone receives a bone vibration signal. Compared with an air conduction microphone, a bone conduction microphone has an advantage in terms of noise resistance. In an environment with high noise, the interference of environmental noise received by the bone conduction microphone is small, and a human voice can be collected well.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Conventional bone conduction microphones have too complex a structure and high requirements for the manufacturing process. Since the connection strength of some devices is insufficient, the reliability is low and the output is affected. Therefore, it is necessary to provide a bone conduction acoustic transmission device with a simple structure and high stability.

Means for Solving the Problems

[0004] A bone conduction acoustic transmission device according to an aspect of the present application includes a laminated structure formed by a vibration unit and an acoustic conversion unit, and a base structure configured to place the laminated structure and physically connected to at least one side of the laminated structure. The base structure generates vibration by an external vibration signal, the vibration unit deforms in response to the vibration of the base structure, and the acoustic conversion unit generates an electrical signal based on the deformation of the vibration unit.

[0005] In some embodiments, the substrate structure includes a frame structure with a hollow interior, and one end of the laminated structure is connected to the substrate structure while the other end is suspended in the hollow position of the substrate structure.

[0006] In some embodiments, the vibration unit includes at least one elastic layer, the acoustic conversion unit includes at least a first electrode layer, a piezoelectric layer, and a second electrode layer arranged in order from top to bottom, and the at least one elastic layer is located on the upper surface of the first electrode layer or the lower surface of the second electrode layer.

[0007] In some embodiments, the acoustic conversion unit further includes a seed layer, and the seed layer is located on the lower surface of the second electrode layer.

[0008] In some embodiments, the covered area of the first electrode layer, the piezoelectric layer, and / or the second electrode layer is not greater than the area of the laminated structure, and the first electrode layer, the piezoelectric layer, and / or the second electrode layer are close to the connection location between the laminated structure and the substrate structure.

[0009] In some embodiments, the vibration unit includes at least one elastic layer, the acoustic conversion unit includes at least an electrode layer and a piezoelectric layer, and the at least one elastic layer is located on the surface of the electrode layer.

[0010] In some embodiments, the electrode layer includes a first electrode and a second electrode, 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 meshes with the second comb-shaped structure to form the electrode layer, and the electrode layer is located on the upper surface or the lower surface of the piezoelectric layer.

[0011] In some embodiments, the first comb-shaped structure and the second comb-shaped structure extend along the longitudinal direction of the laminated structure.

[0012] In some embodiments, the vibration unit includes a suspension film structure, the acoustic conversion unit includes a first electrode layer, a piezoelectric layer, and a second electrode layer that are sequentially arranged from top to bottom, the suspension film structure is connected to the base structure by its circumferential side, and the acoustic conversion unit is located on the upper surface or the lower surface of the suspension film structure.

[0013] In some embodiments, the suspension film structure includes a plurality of holes, and the plurality of holes are distributed along the circumferential direction of the acoustic conversion unit.

[0014] In some embodiments, the radial distance from the edge of the acoustic conversion unit to the center of the plurality of holes is 100 μm to 400 μm.

[0015] In some embodiments, the acoustic conversion unit has an annular structure, and the thickness of the suspension film structure in the inner region of the annular structure is greater than the thickness of the suspension film structure in the outer region of the annular structure.

[0016] In some embodiments, the acoustic conversion unit has an annular structure, and the density of the suspension film structure in the inner region of the annular structure is greater than the density of the suspension film structure in the outer region of the annular structure.

[0017] In some embodiments, the vibration unit further includes a mass element, and the mass element is located on the upper surface or the lower surface of the suspension film structure.

[0018] In some embodiments, the acoustic conversion unit and the mass element are located on different sides of the suspension film structure.

[0019] In some embodiments, the acoustic conversion unit and the mass element are located on the same side of the suspension film structure, the acoustic conversion unit has an annular structure, and the annular structure is distributed along the circumferential direction of the mass element.

[0020] In some embodiments, the vibration unit includes at least one support arm and a mass element, and the mass element is connected to the substrate structure by the at least one support arm.

[0021] In some embodiments, the at least one support arm includes at least one elastic layer, and the acoustic conversion unit is located on the upper surface, lower surface or inside of the at least one support arm.

[0022] In some embodiments, the acoustic conversion unit includes a first electrode layer, a piezoelectric layer and a second electrode layer which are arranged in sequence 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 at least one support arm.

[0023] 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.

[0024] In some embodiments, the area of the first electrode layer, the piezoelectric layer and / or the second electrode layer is less than or equal to the area of the support arm, and a part or all of the first electrode layer, the piezoelectric layer and / or the second electrode layer covers the upper surface or the lower surface of the at least one support arm.

[0025] In some embodiments, the area of the first electrode layer is less than or equal to the area of the piezoelectric layer, and the entire region of the first electrode layer is located on the surface of the piezoelectric layer.

[0026] In some embodiments, the first electrode layer, the piezoelectric layer, and the second electrode layer of the acoustic conversion unit are close to the connection location between the mass element or / and the support arm and the substrate structure.

[0027] In some embodiments, the at least one support arm includes at least one elastic layer, and the at least one elastic layer is located on the upper surface or the lower surface of the first electrode layer or the second electrode layer.

[0028] In some embodiments, it further includes a position limiting structure located in the hollow portion of the substrate structure, and the position limiting structure is connected to the substrate structure and is located above and / or below the mass element.

[0029] In some embodiments, the bone conduction acoustic transmission device according to any one of the foregoing items further includes at least one damping layer covering the upper surface, lower surface and / or inside of the laminated structure.

[0030] This application will be further described in the manner of exemplary embodiments, and these exemplary embodiments will be described in detail with reference to the drawings. These embodiments are not limiting, and in these embodiments, the same reference numerals indicate the same structures.

Brief Description of the Drawings

[0031]

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Embodiments for Carrying Out the Invention

[0032] To more clearly explain the technical means of the embodiments of the present application, the drawings necessary for the description of the embodiments will be briefly described below. Obviously, the drawings described below are only some examples or embodiments of the present application, and those skilled in the art can apply the present application to other similar scenarios based on these drawings without creative effort. Unless it is obvious from the language environment or not specified, the same reference numerals in the drawings indicate the same structure or operation. It should be understood that the drawings are for illustrative and explanatory purposes 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.

[0033] For the sake of facilitating the description of the present application, the positional relationships indicated by terms such as "center", "upper surface", "lower surface", "up", "down", "top", "bottom", "inner", "outer", "axial direction", "radial direction", "outer periphery", "external", etc. are based on the positional relationships shown in the drawings, and it should be understood that they do not indicate that the devices, assemblies or units mentioned must have a specific positional relationship, nor are they intended to limit the present application.

[0034] It should be understood that the "system", "device", "unit" and / or "module" used in this specification are a way to distinguish various assemblies, elements, members, parts or assemblies at different levels. However, other expressions can be used instead of the above terms if other terms can achieve the same purpose.

[0035] As shown in the present application and the claims, unless otherwise clearly indicated throughout the context, terms such as "one", "a", "a kind" and / or "the" do not particularly mean the singular form and may include the plural form. Generally, the terms "comprising" and "containing" only present including the specifically specified steps and elements, and these steps and elements are not an exclusive listing, and the method or device may include other steps or elements.

[0036] In this application, a flowchart is used to describe the operations performed by the system according to the embodiments of this application. It should be understood that the preceding or subsequent operations are not necessarily executed exactly in sequence. Instead, each step may be processed in reverse order, or simultaneously. Also, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0037] The bone conduction acoustic transmission device according to some embodiments of the present application may include a base structure and a laminated structure. In some embodiments, the base structure may be a regular or irregular three-dimensional structure having a hollow portion inside, for example, a hollow frame structure, which may include regular shapes such as a rectangular frame, a circular frame, a regular polygon frame, and any irregular shape, but is not limited thereto. The laminated structure may be located in the hollow portion of the base structure, or may be at least partially suspended in the air above the hollow portion of the base structure. In some embodiments, at least a part of the structure of the laminated structure is physically connected to the base structure. The "connection" here means that after manufacturing the laminated structure and the base structure respectively, the laminated structure and the base structure are fixedly connected by means such as welding, riveting, locking, bolts, etc., or during manufacturing, the laminated structure is deposited on the base structure by means of physical deposition (for example, physical vapor deposition) or chemical deposition (for example, chemical vapor deposition). In some embodiments, at least a part of the structure of the laminated structure may be fixed to the upper surface or the lower surface of the base structure, or may be fixed to the side wall of the base structure. For example, the laminated structure may be a cantilever beam, which may be a plate-like structure, one end of which 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 is not connected or in contact with the base structure, so that it is suspended in the air in the hollow portion of the base structure. Also for example, the laminated structure may include a diaphragm layer (also called a suspension film structure), the suspension film structure is fixedly connected to the base structure, and the laminated structure is installed on the upper surface or the lower surface of the suspension film structure. Further for example, the laminated structure may include a mass element and one or more support arms, the mass element is fixedly connected to the base structure by 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 a part of the region of the mass element and the support arm is suspended in the air in the hollow portion of the base structure. It should be understood that the phrase "located in the hollow portion of the base structure" or "suspended in the air in the hollow portion of the base structure" mentioned in the present application may also mean being suspended in the air inside, below or above the hollow portion of the base structure.In some embodiments, the laminated structure may include a vibration unit and an acoustic conversion unit. Specifically, the substrate structure can generate vibrations by an external vibration signal, the vibration unit deforms in response to the vibrations of the substrate structure, and the acoustic conversion unit generates an electrical signal based on the deformation of the vibration unit. Here, the descriptions of the vibration unit and the acoustic conversion unit are merely for easily explaining the operating principle of the laminated structure, and it should be understood that they do not limit the actual configuration and structure of the laminated structure. In fact, the vibration unit is not essential, and it is entirely possible to realize its function by the acoustic conversion unit. For example, by making specific changes to the structure of the acoustic conversion unit, the acoustic conversion unit may directly generate an electrical signal in response to the vibrations of the substrate structure.

[0038] The vibration unit refers to a portion in the laminated structure that is easily deformed when receiving an external force, and can transmit the deformation caused by the external force to the acoustic conversion unit. In some embodiments, the vibration unit and the acoustic conversion unit are stacked to form the laminated structure. The acoustic conversion unit may be located in the upper layer of the vibration unit or in the lower layer of the vibration unit. For example, when the laminated structure is a cantilever beam structure, the vibration unit may include at least one elastic layer, and the acoustic conversion unit may include a first electrode layer, a piezoelectric layer, and a second electrode layer that are sequentially installed 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 deforms during vibration, the piezoelectric layer generates an electrical signal based on the deformation of the elastic layer, and the first electrode layer and the second electrode layer collect the electrical signal. Also, for example, the vibration unit may be a suspension film structure. By changing the density of a specific region of the suspension film structure, or making holes in the suspension film structure, or installing a counterweight (also called a mass element), etc., the suspension film structure near the acoustic conversion unit is more easily deformed by the action of an external force, thereby driving the acoustic conversion unit to generate an electrical signal. Further, for example, the vibration unit may include at least one support arm and a mass element. The mass element is suspended in the hollow portion of the substrate structure by the support arm. When the substrate structure vibrates, the support arm and the mass element of the vibration unit move relative to the substrate structure, and the support arm deforms and acts on the acoustic conversion unit to generate an electrical signal.

[0039] An acoustic conversion unit is a part in a laminated structure that converts the deformation of a vibration unit into an electrical signal. In some embodiments, the acoustic conversion unit may include at least two electrode layers (e.g., a first electrode layer and a second electrode layer) and a piezoelectric layer, and the piezoelectric layer may be located between the first electrode layer and the second electrode layer. A piezoelectric layer is a structure capable of generating a voltage on both of its end faces under the action of an external force. In some embodiments, the piezoelectric layer may be a piezoelectric polymer film obtained by a semiconductor deposition process (e.g., magnetron sputtering, MOCVD). In the embodiments of this specification, the piezoelectric layer can generate a voltage under the action of 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 may include a piezoelectric crystal material and a piezoelectric ceramic material. A piezoelectric crystal is a piezoelectric single crystal. In some embodiments, the piezoelectric crystal material may include quartz, sphalerite, boracite, tourmaline, zincite, GaAs, barium titanate and its derivative crystals, KH2PO4, NaKC4H4O6·4H2O (Rochelle salt), etc., or any combination thereof. A piezoelectric ceramic material is a piezoelectric polycrystal in which fine crystal grains obtained by a solid-phase reaction and sintering between powders of different materials are randomly aggregated. In some embodiments, the piezoelectric ceramic material may include barium titanate (BT), lead zirconate titanate (PZT), lead barium lithium niobate (PBLN), modified lead titanate (PT), aluminum nitride (AIN), zinc oxide (ZnO), etc., or any combination thereof. In some embodiments, the material of the piezoelectric layer may be a piezoelectric polymer material, such as polyvinylidene fluoride (PVDF), etc.

[0040] In some embodiments, the base structure and the laminated structure may be located within the housing of the bone conduction acoustic transmission device. The base structure is fixedly connected to the inner wall of the housing, and the laminated structure is placed on the base structure. When the housing of the bone conduction acoustic transmission device vibrates under an external force (for example, the housing is vibrated by the vibration of the face when a person speaks), the vibration of the housing causes the base structure to vibrate. Since the attributes of the laminated structure and the housing structure (or the base structure) are different, the laminated structure and the housing cannot move completely in unison. As a result, relative movement occurs, causing the vibration unit of the laminated structure to deform. Further, when the vibration unit deforms, the piezoelectric layer of the acoustic conversion unit generates a potential difference (voltage) under the deformation stress of the vibration unit. At least two electrode layers (for example, the first electrode layer and the second electrode layer) located on the upper and lower surfaces of the piezoelectric layer in the acoustic conversion unit may collect the potential difference and convert the external vibration signal into an electrical signal. For illustrative purposes only, the bone conduction acoustic transmission device described in the embodiments of the present application may be applied to earphones (for example, bone conduction earphones or air conduction earphones), glasses, virtual reality devices, helmets, etc. The bone conduction acoustic transmission device may be disposed at positions such as the human head (for example, the face), neck, near the ear, and the top of the head. The bone conduction acoustic transmission device can collect sound by picking up the vibration signal of the bone when a person speaks and converting it into an electrical signal. It should be noted that the base structure is not limited to a structure independent of the housing of the bone conduction acoustic transmission device. In some embodiments, the base structure may be a part of the housing of the bone conduction acoustic transmission device.

[0041] FIG. 1 is a schematic configuration diagram of a bone conduction acoustic transmission device according to some embodiments of the present application. FIG. 2 is a cross-sectional view taken along line A-A of the bone conduction acoustic transmission device shown in FIG. 1.

[0042] As shown in FIGS. 1 and 2, the bone conduction acoustic transmission device 100 may include a base structure 110 and a laminated structure, and at least a part of the laminated structure is connected to the base structure 110. The base structure 110 may be a frame structure with a hollow interior, and a part of the structure of the laminated structure (for example, the end far from the connection point between the base structure 110 of the laminated structure and the laminated structure) may be located in the hollow part of the frame structure. Note that the frame structure is not limited to the rectangular parallelepiped shape shown in FIG. 1. In some embodiments, the frame structure may be a regular or irregular structure such as a frustum of a pyramid or a cylinder. In some embodiments, the laminated structure may be fixedly connected to the base structure 110 in the form of a cantilever beam. Further, the laminated structure may include a fixed end and a free end. The fixed end of the laminated structure is fixedly connected to the frame structure, and the free end of the laminated structure may be suspended in the hollow part of the frame structure by not being connected to or in contact with the frame structure. In some embodiments, the fixed end of the laminated structure may be connected to the upper surface, the lower surface of the base structure 110, or the side wall where the hollow part of the base structure 110 is located. In some embodiments, a mounting groove adapted to the fixed end of the laminated structure may be further provided on the side wall where the hollow part of the base structure 110 is located, so that the fixed end of the laminated structure may be fitted and connected to the base structure 110. In order to improve the stability between the laminated structure and the base structure 110, in some embodiments, the laminated structure may include a connection base 140. Merely as an example, as shown in FIG. 1, the connection base 140 is fixedly connected to the fixed end of the surface of the laminated structure. In some embodiments, the fixed end of the connection base 140 may be located on the upper surface or the lower surface of the base structure 110. In some embodiments, the fixed end of the connection base 140 may be located on the side wall where the hollow part of the base structure 110 is located. For example, by forming a mounting groove adapted to the fixed end on the side wall where the hollow part of the base structure 110 is located, the fixed end of the laminated structure and the base structure 110 are fitted and connected by the mounting groove.As used herein, "connection" can be understood as fixedly connecting the laminate structure and the substrate structure 110 by means such as welding, riveting, adhesion, bolting, locking, etc. after manufacturing the laminate structure and the substrate structure respectively, or depositing the laminate structure on the substrate structure 110 by means of physical deposition (e.g., physical vapor deposition) or chemical deposition (e.g., chemical vapor deposition) during manufacturing. In some embodiments, the connection base 140 may be a structure independent of the laminate structure or may be integrally formed with the laminate structure.

[0043] In some embodiments, the laminated structure may include an acoustic conversion unit 120 and a vibration unit 130. The vibration unit 130 refers to an elastically deformable portion in the laminated structure, and the acoustic conversion unit 120 refers to a portion that converts the deformation of the vibration unit 130 in the laminated structure into an electrical signal. In some embodiments, the vibration unit 130 may be located on the upper surface or the lower surface of the acoustic conversion unit 120. In some embodiments, the vibration unit 130 may include at least one elastic layer. For illustrative purposes only, the vibration unit 130 shown in FIG. 1 may include a first elastic layer 131 and a second elastic layer 132 installed in order from top to bottom. The first elastic layer 131 and the second elastic layer 132 may be plate-like structures made of a semiconductor material. In some embodiments, the semiconductor material may include silica, 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 may be the same or different. In some embodiments, the acoustic conversion unit 120 includes at least a first electrode layer 121, a piezoelectric layer 122, and a second electrode layer 123 installed in order from top to bottom, and the elastic layer (for example, the first elastic layer 131 and the second elastic layer 132) may be located on the upper surface of the first electrode layer 121 or the lower surface of the second electrode layer 123. Based on the piezoelectric effect, the piezoelectric layer 122 can generate a voltage (potential difference) under the action of the deformation stress of the vibration unit 130 (for example, the first elastic layer 131 and the second elastic layer 132), and the first electrode layer 121 and the second electrode layer 123 can derive the voltage (electrical signal). In some embodiments, the material of the piezoelectric layer may include a piezoelectric crystal material and a piezoelectric ceramic material. A piezoelectric crystal material is a piezoelectric single crystal. In some embodiments, the piezoelectric crystal material may include quartz, sphalerite, boracite, tourmaline, zincite, GaAs, barium titanate and its derivative crystals, KH2PO4, NaKC4H4O6·4H2O (Rochelle salt), etc., or any combination thereof. A piezoelectric ceramic material is a piezoelectric polycrystal in which fine crystal grains obtained by a solid-phase reaction and sintering between powders of different materials are randomly aggregated.In some embodiments, the piezoelectric ceramic material may include barium titanate (BT), lead zirconate titanate (PZT), barium lithium niobate (PBLN), modified lead titanate (PT), aluminum nitride (AIN), zinc oxide (ZnO), etc., or any combination thereof. In some embodiments, the material of the piezoelectric layer may 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 may include metals, alloy materials, metal oxide materials, graphene, etc., or any combination thereof. In some embodiments, the metals and alloy materials may include nickel, iron, lead, platinum, titanium, copper, molybdenum, zinc, or any combination thereof. In some embodiments, the alloy materials may include copper-zinc alloy, copper-tin alloy, copper-nickel-silicon alloy, copper-chromium alloy, copper-silver alloy, etc., or any combination thereof. In some embodiments, the metal oxide materials may include RuO2, MnO2, PbO2, NiO, etc., or any combination thereof.

[0044] When the laminated structure and the base structure 110 move relative to each other, the degree of deformation at different positions of the vibration unit 130 (for example, the first elastic layer 131 or the second elastic layer 132) of the laminated structure is different. That is, the deformation stress on the piezoelectric layer 122 of the acoustic conversion unit 120 from different positions of the vibration unit 130 is different. In order to improve the sensitivity of the bone conduction acoustic transmission device, in some embodiments, by installing the acoustic conversion unit 120 only at the position where the degree of deformation of the vibration unit 130 is large, the signal-to-noise ratio of the bone conduction acoustic transmission device 100 can be improved. Therefore, the area of the first electrode layer 121, the piezoelectric layer 122, and / or the second electrode layer 123 of the acoustic conversion unit 120 may be equal to or less 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 acoustic transmission device 100, the area of the vibration unit 130 covered by the acoustic conversion unit 120 is equal to or less than 1 / 2 of the area of the vibration unit 130. Preferably, the area of the vibration unit 130 covered by the acoustic conversion unit 120 is equal to or less than 1 / 3 of the area of the vibration unit 130. More preferably, the area of the vibration unit 130 covered by the acoustic conversion unit 120 is equal to or less than 1 / 4 of the area of the vibration unit 130. Further, in some embodiments, the position of the acoustic conversion unit 120 may be close to the connection portion between the laminated structure and the base structure 110. When the vibration unit 130 (for example, the elastic layer) receives an external force near the connection portion between the laminated structure and the base structure 110, the degree of deformation generated is large, and the deformation stress received by the acoustic conversion unit 120 near the connection portion between the laminated structure and the base structure 110 is also large. By arranging the acoustic conversion unit 120 in the region where the deformation stress is large, the sensitivity of the bone conduction acoustic transmission device 100 can be improved, and the signal-to-noise ratio of the bone conduction acoustic transmission device 100 can be improved. Here, the fact that the acoustic conversion unit 120 may be close to the connection portion between the laminated structure and the base structure 110 is with respect to the free end of the laminated structure. That is, the distance from the acoustic conversion unit 120 to the connection portion between the laminated structure and the base structure 110 is smaller than the distance from the acoustic conversion unit 120 to the free end.In some embodiments, the sensitivity and signal-to-noise ratio of the bone conduction acoustic transmission device 100 can be improved only by adjusting the area and position of the piezoelectric layer 122 in the acoustic conversion unit 120. For example, the first electrode layer 121 and the second electrode layer 123 are completely or partially covered on the surface of the vibration unit 130, and the area of the piezoelectric layer 122 may be equal to or less than the area of the first electrode layer 121 or the second electrode layer 123. In some embodiments, the area of the first electrode layer 121 or the second electrode layer 123 covered by the piezoelectric layer 122 is equal to or less than 1 / 2 of the area of the first electrode layer 121 or the second electrode layer 123. Preferably, the area of the first electrode layer 121 or the second electrode layer 123 covered by the piezoelectric layer 122 is equal to or less than 1 / 3 of the area of the first electrode layer 121 or the second electrode layer 123. More preferably, the area of the first electrode layer 121 or the second electrode layer 123 covered by the piezoelectric layer 122 is equal to or less than 1 / 4 of the area of the first electrode layer 121 or the second electrode layer 123. In some embodiments, in order to prevent the problem that the first electrode layer 121 and the second electrode layer 123 are connected and a short circuit occurs, 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 areas of the piezoelectric layer 122, the second electrode layer 123, and the vibration unit 130 are the same, and the area of the first electrode layer 121 is smaller than the area of the vibration unit 130 (for example, the elastic layer), the piezoelectric layer 122, or the second electrode layer 123. In this case, since the entire region 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 is separated from the edge of the piezoelectric layer 122 by a certain distance, the first electrode layer 121 can further improve the signal-to-noise ratio of the bone conduction acoustic transmission device 100 by avoiding the region with low material quality at the edge of the piezoelectric layer 122.

[0045] In some embodiments, in order to increase the output electrical signal and improve the signal-to-noise ratio of the bone conduction acoustic transmission device, the piezoelectric layer 122 may be located on one side of the neutral layer of the laminated structure. The neutral layer is a planar layer in the laminated structure where the deformation stress is approximately zero during deformation. In some embodiments, by adjusting (e.g., increasing) the stress and the stress change gradient per unit thickness of the piezoelectric layer 122, the signal-to-noise ratio of the bone conduction acoustic transmission device can be improved. In some embodiments, by adjusting the shape, thickness, material, and size (e.g., length, width, and thickness) of the acoustic conversion 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, the second elastic layer 132), the signal-to-noise ratio and sensitivity of the bone conduction acoustic transmission device 100 can be improved.

[0046] In some embodiments, in order to solve the problem of warping deformation of the laminated structure, by balancing the stresses of each layer in the laminated structure, it is necessary to make the types (e.g., tensile stress, compressive stress) of the stresses received by the upper and lower parts of the neutral layer of the cantilever beam the same and the magnitudes equal. For example, when the piezoelectric layer 122 is an AIN material layer, the piezoelectric layer 122 is installed on one side of the neutral layer of the cantilever beam. The AIN material layer generally receives tensile stress, and the total stress received by the elastic layer located on the other side of the neutral layer should also be tensile stress.

[0047] In some embodiments, the acoustic conversion unit 120 may further include a seed layer (not shown) that provides a good growth surface structure for other layers, and the seed layer is located on the lower surface of the second electrode layer 123. In some embodiments, the material of the seed layer may 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. Note that when the acoustic conversion unit 120 is located on the lower surface of the second electrode layer 123, the seed layer may be located on the upper surface of the first electrode layer 121. Further, when the acoustic conversion unit 120 includes a seed layer, the vibration unit 130 (for example, the first elastic layer 131 and the second elastic layer 132) may be located on the surface of the seed layer away from the piezoelectric layer 122. In other embodiments, the material of the seed layer may be different from that of the piezoelectric layer 122.

[0048] Note that the shape of the stacked structure is not limited to the rectangle shown in FIG. 1, and may be a regular or irregular shape such as a triangle, trapezoid, circle, semicircle, quarter circle, ellipse, semi-ellipse, etc., and is not further limited in this specification. Also, the number of stacked structures is not limited to one shown in FIG. 1, and may be two, three, four or more. Various stacked structures may be arranged side by side in the air in the hollow portion of the substrate structure, or may be sequentially installed in the air in the hollow portion of the substrate structure along the arrangement direction of each layer of the stacked structure.

[0049] FIG. 3 is a schematic configuration diagram of another bone conduction acoustic transmission device shown in some embodiments of the present application. The bone conduction acoustic transmission device 300 shown in FIG. 3 is substantially the same as the bone conduction acoustic transmission device 100 shown in FIG. 1, and the biggest difference is that the shape of the laminated structure of the bone conduction acoustic transmission device 300 shown in FIG. 3 is different from that thereof. As shown in FIG. 3, the bone conduction acoustic transmission device 300 includes a base structure 310 and a laminated structure, and the shape of the laminated structure is trapezoidal. Further, the width of the laminated structure of the bone conduction acoustic transmission device 300 gradually decreases from the free end to the fixed end. In other embodiments, the width of the laminated structure of the bone conduction acoustic transmission device 300 may gradually increase from the free end to the fixed end. Here, the structure of the base structure 310 is similar to the structure of the base structure 110, and the structure of the vibration unit 330 is similar to the structure of the vibration unit 130. For details of each layer such as the first electrode 321, the piezoelectric layer 322, and the second electrode 323 of the acoustic conversion unit 320, and the first elastic layer 331 and the second elastic layer 332 of the vibration unit 330, reference can be made to the content of each layer of the acoustic conversion unit 120 and the vibration unit 130 in FIG. 1. In addition, other members (for example, seed layers) in the acoustic conversion unit 120 and the vibration unit 130 are similarly applied to the bone conduction acoustic transmission device 300 shown in FIG. 3, and the description thereof is omitted in this specification.

[0050] FIG. 4 is a schematic configuration diagram of a bone conduction acoustic transmission device according to another embodiment of the present application. As shown in FIG. 4, the bone conduction acoustic transmission device 400 may include a base structure 410 and a laminated structure, and at least a part of the laminated structure is connected to the base structure 410. In some embodiments, the base structure 410 may be a frame structure with a hollow interior, and a part of the structure of the laminated structure (for example, an end away from the connection point between the base structure 410 of the laminated structure and the laminated structure) may be located in the hollow portion of the frame structure. Note that the frame structure is not limited to the rectangular parallelepiped shape shown in FIG. 4, and in some embodiments, the frame structure may be a regular or irregular structure such as a frustum of a pyramid or a cylinder. In some embodiments, the laminated structure may be fixedly connected to the base structure 410 in the form of a cantilever beam. Further, the laminated structure may include a fixed end and a free end. The fixed end of the laminated structure is fixedly connected to the frame structure, and the free end of the laminated structure may be suspended in the hollow portion of the frame structure by not being connected or in contact with the frame structure. In some embodiments, the fixed end of the laminated structure may be connected to the upper surface, the lower surface of the base structure 410, or the side wall where the hollow portion of the base structure 410 is located. In some embodiments, a mounting groove adapted to the fixed end of the laminated structure may be further provided on the side wall where the hollow portion of the base structure 410 is located, so that the fixed end of the laminated structure may be fitted and connected to the base structure 410. The "connection" here can be understood as fixedly connecting the laminated structure and the base structure 410 by means such as welding, riveting, locking, and bolt connection after manufacturing the laminated structure and the base structure respectively. In some embodiments, during manufacturing, the laminated structure may be deposited on the base structure 410 by physical deposition (for example, physical vapor deposition) or chemical deposition (for example, chemical vapor deposition). In some embodiments, one or more laminated structures may be provided on the base structure 410. For example, the number of laminated structures may be one, two, three, seven, etc. Further, the plurality of laminated structures may be uniformly arranged at equal intervals along the circumferential direction of the base structure 410, or may be non-uniformly arranged.

[0051] In some embodiments, the laminated structure may include an acoustic conversion unit 420 and a vibration unit 430. The vibration unit 430 may be located on the upper surface or the lower surface of the acoustic conversion unit 420. In some embodiments, the vibration unit 430 may include at least one elastic layer. The elastic layer may be a plate-like structure made of a semiconductor material. In some embodiments, the semiconductor material may include silica, silicon nitride, gallium nitride, zinc oxide, silicon carbide, and the like. In some embodiments, the acoustic conversion unit 420 may include an electrode layer and a piezoelectric layer 423, and 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 action of the deformation stress of the vibration unit 430 based on the piezoelectric effect, and the first electrode 421 and the second electrode 422 can derive the voltage (electrical signal). In some embodiments, the first electrode 421 and the second electrode 422 are installed at intervals on the same surface (for example, the upper surface or the lower surface) of the piezoelectric layer 423, and the electrode layer and the vibration unit 430 are located on different surfaces of the piezoelectric layer 423. For example, when the vibration 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) may be located on the upper surface of the piezoelectric layer 423. Also, for example, when the vibration 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) may be located on the lower surface of the piezoelectric layer 423. In some embodiments, the electrode layer and the vibration unit 430 may 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 vibration unit 430. In some embodiments, the first electrode 421 may be bent into a first comb-shaped structure 4210, the first comb-shaped structure 4210 may include a plurality of comb structures, and there is a first interval between adjacent comb structures of the first comb-shaped structure 4210, and the first interval may be the same or different. The second electrode 422 may be bent into a second comb-shaped structure 4220, the second comb-shaped structure 4220 may include a plurality of comb structures, and there is a second interval between adjacent comb structures of the second comb-shaped structure 4220, and the second interval may be the same or different.The first comb-shaped structure 4210 fits with the second comb-shaped structure 4220 to form an electrode layer. Further, the comb structure of the first comb-shaped structure 4210 enters into the second interval of the second comb-shaped structure 4220, and the comb structure of the second comb-shaped structure 4220 enters into the first interval of the first comb-shaped structure 4210, so that they may fit with each other to form an electrode layer. By fitting the first comb-shaped structure 4210 and the second comb-shaped structure 4220 with each other, the first electrode 421 and the second electrode 422 are arranged compactly but do not cross each other. In some embodiments, the first comb-shaped structure 4210 and the second comb-shaped structure 4220 extend along the longitudinal direction of the cantilever beam (for example, the direction from the fixed end to the free end). In some embodiments, the piezoelectric layer 423 is preferably made of a piezoelectric ceramic material. When the piezoelectric layer 423 is a piezoelectric ceramic material, the polarization direction of the piezoelectric layer 423 coincides with the longitudinal direction of the cantilever beam, and the piezoelectric constant d of the piezoelectric ceramic. 33 of the characteristics is utilized to greatly enhance the output signal and improve the sensitivity. The piezoelectric constant d 33 is a proportionality constant for converting mechanical energy of the piezoelectric layer into electrical energy. Note that the piezoelectric layer 423 shown in FIG. 4 may be made of other materials. When the polarization direction of the piezoelectric layer 423 of other materials coincides with the thickness direction of the cantilever beam, the acoustic conversion unit 420 may be replaced by the acoustic conversion unit 120 shown in FIG. 1.

[0052] When the laminated structure and the base structure 410 move relative to each other, the degree of deformation at different positions of the vibration unit 430 of the laminated structure is different. That is, the deformation stress on the piezoelectric layer 423 of the acoustic conversion unit 420 from different positions of the vibration unit 430 is different. In order to improve the sensitivity of the bone conduction acoustic transmission device, in some embodiments, by installing the acoustic conversion unit 420 only at the position where the degree of deformation of the vibration unit 430 is large, the signal-to-noise ratio of the bone conduction acoustic transmission device 400 can be improved. Therefore, the area of the electrode layer and / or the piezoelectric layer 423 of the acoustic conversion unit 420 may be equal to or less 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 acoustic transmission device 400, the area of the vibration unit 430 covered by the acoustic conversion unit 420 is equal to or less than the area of the vibration unit 430. Preferably, the area of the vibration unit 430 covered by the acoustic conversion unit 420 is equal to or less than 1 / 2 of the area of the vibration unit 430. Preferably, the area of the vibration unit 430 covered by the acoustic conversion unit 420 is equal to or less than 1 / 3 of the area of the vibration unit 430. More preferably, the area of the vibration unit 430 covered by the acoustic conversion unit 420 is equal to or less than 1 / 4 of the area of the vibration unit 430. Further, in some embodiments, the acoustic conversion unit 420 may be close to the connection location between the laminated structure and the base structure 410. When the vibration unit 430 (for example, the elastic layer) receives an external force near the connection location between the laminated structure and the base structure 410, the degree of deformation generated is large, and the deformation stress received by the acoustic conversion unit 420 near the connection location between the laminated structure and the base structure 410 is also large. Therefore, by arranging the acoustic conversion unit 420 in the region where the deformation stress is large, the sensitivity of the bone conduction acoustic transmission device 400 can be improved, and the signal-to-noise ratio of the bone conduction acoustic transmission device 400 can be improved. Here, the fact that the acoustic conversion unit 420 may be close to the connection location between the laminated structure and the base structure 410 is with respect to the free end of the laminated structure. That is, the distance from the acoustic conversion unit 420 to the connection location between the laminated structure and the base structure 410 is smaller than the distance from the acoustic conversion unit 420 to the free end.In some embodiments, by simply adjusting the area and position of the piezoelectric layer 423 in the acoustic conversion unit 420, the sensitivity and signal-to-noise ratio of the bone conduction acoustic transmission device 400 can be improved. For example, the electrode layer may be completely or partially covered on the surface of the vibration unit 430, and the area of the piezoelectric layer 423 may be equal to or less than the area of the electrode layer. Preferably, the area of the vibration unit 130 covered by the piezoelectric layer 423 is equal to or less than 1 / 2 of the area of the electrode layer. Preferably, the area of the vibration unit 430 covered by the piezoelectric layer 423 is equal to or less than 1 / 3 of the area of the piezoelectric layer. More preferably, the area of the vibration unit 430 covered by the piezoelectric layer 423 is equal to or less than 1 / 4 of the area of the electrode layer. In some embodiments, the area of the piezoelectric layer 423 may be the same as the area of the vibration unit 430, the entire area of the electrode layer may be located on the piezoelectric layer 423, and by separating the edge of the electrode layer from the edge of the piezoelectric layer 423 by a certain distance, the first electrode 421 and the second electrode 422 of the electrode layer can avoid the region with low material quality at the edge of the piezoelectric layer 423, thereby further improving the signal-to-noise ratio of the bone conduction acoustic transmission device 400.

[0053] In some embodiments, in order to increase the output electrical signal and improve the signal-to-noise ratio of the bone conduction acoustic transmission device, by adjusting the shape, thickness, material, and size (e.g., length, width, thickness) of the acoustic conversion 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), the signal-to-noise ratio and sensitivity of the bone conduction acoustic transmission device 400 can be improved.

[0054] In some embodiments, in order to increase the output electrical signal and improve the signal-to-noise ratio of the bone conduction acoustic transmission device, by adjusting the length, width, the interval between the comb tooth structures (e.g., the first interval and the second interval), and the overall length of the acoustic conversion unit 420 of the first comb tooth structure 4210 and the second comb tooth structure 4220, the output voltage electrical signal can be increased, and the signal-to-noise ratio of the bone conduction acoustic transmission device can also be improved.

[0055] FIG. 5 is a schematic configuration diagram of a bone conduction acoustic transmission device according to some embodiments of the present application. FIG. 6 is a cross-sectional view of a local structure of the bone conduction acoustic transmission device shown in FIG. 5. As shown in FIGS. 5 and 6, the bone conduction acoustic transmission device 500 may include a base structure 510 and a laminated structure, and at least a part of the laminated structure is connected to the base structure 510. In some embodiments, the base structure 510 may be a frame structure with a hollow interior, and a part of the structure of the laminated structure may be located in the hollow portion of the frame structure. Note that the frame structure is not limited to the rectangular parallelepiped shape shown in FIG. 5, and in some embodiments, the frame structure may be a regular or irregular structure such as a frustum of a pyramid or a cylinder.

[0056] In some embodiments, the stacked structure may include an acoustic conversion unit 520 and a vibration unit. In some embodiments, the vibration unit may be installed on the upper surface or the lower surface of the acoustic conversion unit 520. As shown in FIG. 5, the vibration unit includes a suspension film structure 530. The suspension film structure 530 is connected to and fixed to the base structure 510 by the peripheral side, and the central region of the suspension film structure 530 is installed in the hollow portion of the base structure 510 in a suspended manner. In some embodiments, the suspension film structure 530 may be located on the upper surface or the lower surface of the base structure 510. In some embodiments, the peripheral side of the suspension film structure 530 may be connected to the inner wall of the hollow portion of the base structure 510. The "connection" here means that after manufacturing the suspension film structure 530 and the base structure 510 respectively, the suspension film structure 530 is fixed to 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 (such as a method of strong adhesion, rivet connection, clip, fitting, etc.), or during manufacturing, the suspension film structure 530 is deposited on the base structure 510 by a method of physical deposition (such as physical vapor deposition) or chemical deposition (such as chemical vapor deposition). In some embodiments, the suspension film structure 530 may include at least one elastic layer. The elastic layer may be a film structure made of a semiconductor material. In some embodiments, the semiconductor material may include silica, silicon nitride, gallium nitride, zinc oxide, silicon carbide, etc. In some embodiments, the shape of the suspension film structure 530 may be a polygon such as a circle, an ellipse, a triangle, a quadrilateral, a pentagon, a hexagon, or any other arbitrary shape.

[0057] In some embodiments, the acoustic conversion unit 520 may be located on the upper or lower surface of the suspension film structure 530. In some embodiments, the suspension film structure 530 may include a plurality of holes 5300, and the plurality of holes 5300 are distributed along the circumferential direction of the acoustic conversion unit 520 with the center of the acoustic conversion unit 520 as the center. By providing the plurality of holes 5300 in the suspension film structure 530, the rigidity of different positions of the suspension film structure 530 can be adjusted, the rigidity of the suspension film structure 530 in the region near the plurality of holes 5300 can be reduced, and the rigidity of the suspension film structure 530 in the region away from the plurality of holes 5300 can be relatively increased. When the suspension film structure 530 and the base structure 510 move relative to each other, the degree of deformation of the suspension film structure 530 in the region near the plurality of holes 5300 is large, and the degree of deformation of the suspension film structure 530 in the region away from the plurality of holes 5300 is small. At this time, if the acoustic conversion unit 520 is arranged in the region near the plurality of holes 5300 on the suspension film structure 530, it is helpful for collecting the vibration signal by the acoustic conversion unit 520, effectively improving the sensitivity of the bone conduction acoustic transmission device 500, and since the structure of each member of the bone conduction acoustic transmission device 500 is simple, it can be understood that the manufacturing or assembly becomes easy. In some embodiments, the holes 5300 on the suspension film structure 530 may be of any shape such as circular holes, elliptical holes, square holes, and other polygonal holes. In some embodiments, by changing the size, number, spacing distance, and position of the plurality of holes 5300 to adjust the resonance frequency (the resonance frequency is set to 2 kHz to 5 kHz) and stress distribution of the bone conduction acoustic transmission device 500, the sensitivity of the bone conduction acoustic transmission device 500 can also be improved. It should be noted that the resonance frequency is not limited to the above 2 kHz to 5 kHz, and may also be 3 kHz to 4.5 kHz or 4 kHz to 4.5 kHz. The range of the resonance frequency can be adaptively adjusted according to various application scenarios and is not further limited in this specification.

[0058] 5 and 6, in some embodiments, the acoustic transducer unit 520 may include a first electrode layer 521, a piezoelectric layer 522, and a second electrode layer 523, which are arranged in order from top to bottom, or the positions of the first electrode layer 521 and the second electrode layer 523 may be reversed. The piezoelectric layer 522 can generate a voltage (potential difference) under the action of a deformation stress of a vibration unit (e.g., a suspension membrane structure 530) based on the piezoelectric effect, and the first electrode layer 521 and the second electrode layer 523 can derive the voltage (electrical signal). In some embodiments, the material of the piezoelectric layer may include a piezoelectric crystal material and a piezoelectric ceramic material. The piezoelectric crystal is a piezoelectric single crystal. In some embodiments, the piezoelectric crystal material may include quartz, zinc blende, boron, tourmaline, zincite, GaAs, barium titanate and its derivative crystals, KH2PO4, NaKC4H4O6·4H2O (Rochelle salt), sugar, etc., or any combination thereof. Piezoelectric ceramic materials are piezoelectric polycrystals with randomly assembled fine grains obtained by solid-state reaction and sintering between powders of different materials. In some embodiments, the piezoelectric ceramic materials may include barium titanate (BT), lead zirconate titanate (PZT), lead barium lithium niobate (PBLN), modified lead titanate (PT), aluminum nitride (AIN), zinc oxide (ZnO), and the like, or any combination thereof. In some embodiments, the material of the piezoelectric layer 522 may be a piezoelectric polymer material, such as polyvinylidene fluoride (PVDF), and the like. In some embodiments, the first electrode layer 521 and the second electrode layer 523 are conductive material structures. Exemplary conductive materials may include metals, alloy materials, metal oxide materials, graphene, and the like, or any combination thereof. In some embodiments, the metals and alloy materials may include nickel, iron, lead, platinum, titanium, copper, molybdenum, zinc, and the like, or any combination thereof. In some embodiments, the alloy material may 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 may include RuO2, MnO2, PbO2, NiO, etc., or any combination thereof.

[0059] As shown in FIG. 5, in some embodiments, the plurality of holes 5300 surround a circular region. To improve the sound pressure output effect of the acoustic conversion unit 520, the acoustic conversion unit 520 may be installed in a region close to the plurality of holes 5300 in the suspension film structure 530. Further, the acoustic conversion unit 520 may be an annular structure and may be distributed along the inner side of the circular region surrounded by the plurality of holes 5300. In some embodiments, the annular acoustic conversion unit 520 may be distributed along the outer side of the circular region surrounded by the plurality of holes 5300. In some embodiments, the piezoelectric layer 522 of the acoustic conversion unit 520 may be a piezoelectric ring, and the first electrode layer 521 and the second electrode layer 523 located on the upper and lower surfaces of the piezoelectric ring may be electrode rings. In some embodiments, a lead structure 5200 is further formed on the acoustic conversion unit 520, and the lead structure 5200 transmits the electrical signal collected by the electrode rings (for example, the first electrode layer 521 and the second electrode layer 523) to a subsequent circuit. In some embodiments, in order to improve the output electrical signal of the bone conduction acoustic transmission device 500, the radial interval from the edge of the acoustic conversion unit 520 (for example, an annular structure) to the center of each hole 5300 may be 100 μm to 400 μm. Preferably, the radial interval from the edge of the acoustic conversion unit 520 (for example, an annular structure) to the center of each hole 5300 may be 150 μm to 300 μm. More preferably, the radial interval from the edge of the acoustic conversion unit 520 (for example, an annular structure) to the center of each hole 5300 may be 150 μm to 250 μm.

[0060] In some embodiments, by adjusting the shape, size (for example, length, width, and thickness), and material of the lead structure 5200, the output electrical signal of the bone conduction acoustic transmission device 500 can also be improved.

[0061] In some alternative embodiments, the thickness or density of different regions of the suspension film structure 530 may be further adjusted to vary the deformation stress at different positions of the suspension film structure 530. For the purpose of only exemplary illustration, in some embodiments, the acoustic conversion unit 520 has an annular structure, and the thickness of the suspension film structure 530 in the inner region of the annular structure is greater than the thickness of the suspension film structure 530 in the outer region of the annular structure. In some other embodiments, the density of the suspension film structure 530 in the inner region of the annular structure is greater than the density of the suspension film structure 530 in the outer region of the annular structure. By changing the density or thickness at different positions of the suspension film structure 530, the mass of the suspension film in the inner region of the annular structure is greater than the mass of the suspension film in the outer region of the annular structure. When the suspension film structure 530 and the base structure 510 move relative to each other, the degree of deformation generated by the suspension film structure 530 near the annular structure of the acoustic conversion unit 520 is large, and the generated deformation stress is also large. As a result, the output electrical signal of the bone conduction acoustic transmission device 500 is improved.

[0062] Note that the shape of the region surrounded by the plurality of holes 5300 is not limited to the circular shape shown in FIG. 5, and may be other regular or irregular shapes such as a semi-circular shape, a quarter-circular shape, an elliptical shape, a semi-elliptical shape, a triangular shape, a rectangular shape, etc. The shape of the acoustic conversion unit 520 can be adaptively adjusted according to the shape of the region surrounded by the plurality of holes 5300. For example, when the shape of the region surrounded by the plurality of holes 5300 is rectangular, the shape of the acoustic conversion unit 520 may be rectangular, and the rectangular acoustic conversion unit 520 may be distributed along the inside or outside of the rectangle surrounded by the plurality of holes 5300. Also, for example, when the shape of the region surrounded by the plurality of holes 5300 is semi-circular, the shape of the acoustic conversion unit 520 may be semi-annular, and the semi-annular acoustic conversion unit 520 may be distributed along the inside or outside of the semi-circle surrounded by the plurality of holes 5300. In some embodiments, it may not be necessary to make holes in the suspension film structure 530 shown in FIG. 5.

[0063] FIG. 7 is a schematic configuration diagram of a bone conduction acoustic transmission device according to some embodiments of the present application. The structure of the bone conduction acoustic transmission device 700 shown in FIG. 7 is substantially the same as the structure of the bone conduction acoustic transmission device 500 shown in FIG. 5, but is different in that the vibration unit of the bone conduction acoustic transmission device 700 shown in FIG. 7 includes a suspension film structure 730 and a mass element 740.

[0064] As shown in FIG. 7, the bone conduction acoustic transmission device 700 may include a base structure 710 and a laminated structure, and at least a part of the laminated structure is connected to the base structure 710. In some embodiments, the base structure 710 may be a frame structure with a hollow interior, and a part of the structure of the laminated structure may be located in the hollow portion of the frame structure. Note that the frame structure is not limited to the rectangular parallelepiped shape shown in FIG. 7, and in some embodiments, the frame structure may be a regular or irregular structure such as a frustum of a pyramid or a cylinder.

[0065] In some embodiments, the laminated structure may include an acoustic conversion unit 720 and a vibration unit. In some embodiments, the vibration unit may be disposed on the upper surface or the lower surface of the acoustic conversion unit 720. As shown in FIG. 7, the vibration unit includes a suspension film structure 730 and a mass element 740, and the mass element 740 may be located on the upper surface or the lower surface of the suspension film structure 730. In some embodiments, the suspension film structure 730 may be located on the upper surface or the lower surface of the base structure 710. In some embodiments, the peripheral side of the suspension film structure 730 may be connected to the inner wall of the hollow portion of the base structure 710. The "connection" here can be understood as that after manufacturing the suspension film structure 730 and the base structure 710 respectively, the suspension film structure 730 is fixed to the upper surface, the lower surface of the base structure 710 or the side wall of the hollow portion of the base structure 710 by a mechanical fixing method (such as methods of strong adhesion, rivet connection, clip, fitting, etc.), or during manufacturing, the suspension film structure 730 is deposited on the base structure 710 by a physical deposition (such as physical vapor deposition) or a chemical deposition (such as chemical vapor deposition) method. When the vibration unit and the base structure 710 move relative to each other, the weights of the mass element 740 and the suspension film structure 730 themselves are different, and the degree of deformation of the region where the mass element 740 is located or the region near it in the suspension film structure 730 is greater than the degree of deformation of the region away from the mass element 740 in the suspension film structure 730. In order to improve the output sound pressure of the bone conduction acoustic transmission device 700, the acoustic conversion unit 720 may be distributed along the circumferential direction of the mass element 740. In some embodiments, the shape of the acoustic conversion unit 720 may be the same as or different from the shape of the mass element 740. Preferably, the shape of the acoustic conversion unit 720 may be the same as the shape of the mass element 740, so that each position of the acoustic conversion unit 720 can be close to the mass element 740, and as a result, the output electrical signal of the bone conduction acoustic transmission device 700 can be further improved.For example, the mass element 740 has a cylindrical structure, and the acoustic conversion unit 720 may have an annular structure. Since the inner diameter of the annular acoustic conversion unit 720 is larger than the radius of the mass element 740, the acoustic conversion unit 720 is installed along the circumferential direction of the mass element 740. In some embodiments, the acoustic conversion unit 720 may include a first electrode layer, a second electrode layer, and a piezoelectric layer located between the two electrode layers. The first electrode layer, the piezoelectric layer, and the second electrode layer are combined into a structure that conforms to the shape of the mass element 740. For example, the mass element 740 has a cylindrical structure, and the acoustic conversion unit 720 may have an annular structure. At this time, the first electrode layer, the piezoelectric layer, and the second electrode layer all have an annular structure, and the three are installed in order from top to bottom and combined into an annular structure.

[0066] In some embodiments, the acoustic conversion unit 720 and the mass element 740 may be located on different sides of the suspension film structure 730, or may be located on the same side of the suspension film structure 730. For example, both the acoustic conversion unit 720 and the mass element 740 are located on the upper surface or the lower surface of the suspension film structure 730, and the acoustic conversion unit 720 is distributed along the circumferential direction of the mass element 740. Also for example, the acoustic conversion unit 720 is located on the upper surface of the suspension film structure 730, and the mass element 740 is located on the lower surface of the suspension film structure 730. At this time, the projection of the mass element 740 onto the suspension film structure 730 is within the region of the acoustic conversion unit 720.

[0067] In some embodiments, by changing the size, shape, position of the mass element 740 and the position, shape, and size of the piezoelectric layer, the output electrical signal of the bone conduction acoustic transmission device 700 can be improved. In some embodiments, by changing the shape, material, and size of the suspension film structure 730, the sound pressure output effect of the bone conduction acoustic transmission device 700 can also be improved. Here, the first electrode layer, the second electrode layer, and the piezoelectric layer of the acoustic conversion unit 720 and the first electrode layer 521, the second electrode layer 523, and the piezoelectric layer 522 of the acoustic conversion unit 520 shown in FIG. 5 are similar in structure and parameters, etc. The suspension film structure 730 and the suspension film structure 530 are similar in structure and parameters, etc. The lead structure 7200 and the lead structure 5200 are similar in structure and will not be further described in this specification.

[0068] FIG. 8 is a schematic configuration diagram of a bone conduction acoustic transmission device according to some embodiments of the present application. FIG. 9 is a cross-sectional view taken along line C-C of the bone conduction acoustic transmission device shown in FIG. 8. As shown in FIG. 8, the base structure 810 has a rectangular parallelepiped frame structure. In some embodiments, the interior of the base structure 810 may include a hollow portion for arranging the acoustic conversion unit 820 and the vibration unit. In some embodiments, the shape of the hollow portion may be other regular or irregular shapes such as circular, quadrilateral (e.g., rectangular, parallelogram), pentagonal, hexagonal, heptagonal, octagonal, etc. In some embodiments, the size of one side of the rectangular cavity may be 0.8 mm to 2 mm. Preferably, the size of one side of the rectangular cavity may be 1 mm to 1.5 mm. In some embodiments, the vibration unit may include four support arms 830 and a mass element 840. One end of the four support arms 830 is connected to the upper surface, lower surface of the base structure 810 or the side wall where the hollow portion of the base structure 810 is located, and the other end is connected to the upper surface, lower surface or circumferential side wall of the mass element 840. In some embodiments, the mass element 840 may protrude upward and / or downward with respect to the support arm 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 with respect to the support arm 830. Also, for 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 with respect to the support arm 830. Further, for example, when the ends of the four support arms 830 are connected to the circumferential side wall of the mass element 840, the mass element 840 may protrude upward and downward with respect to the support arm 830. In some embodiments, the shape of the support arm 830 is trapezoidal, the end with a smaller width of the support arm 830 is connected to the mass element 840, and the end with a larger width of the support arm 830 is connected to the base structure 810.

[0069] In some embodiments, the support arm 830 may include at least one elastic layer. The elastic layer may be a plate-like structure made of a semiconductor material. In some embodiments, the semiconductor material may include silicon, silica, silicon nitride, gallium nitride, zinc oxide, silicon carbide, etc. In some embodiments, the materials of the different elastic layers of the support arm 830 may be the same or different. Further, the bone conduction acoustic transmission device 800 may include an acoustic conversion unit 820. The acoustic conversion unit 820 may include a first electrode layer 821, a 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 may be connected to the upper surface or the lower surface of the support arm 830 (for example, the elastic layer). In some embodiments, when the support arm 830 is a plurality of elastic layers, the acoustic conversion unit 820 may be located between the plurality of elastic layers. The piezoelectric layer 822 can generate a voltage (potential difference) under the action of the deformation stress of the vibration unit (for example, the support arm 830 and the mass element 840) based on the piezoelectric effect, and the first electrode layer 821 and the second electrode layer 823 can derive the voltage (electrical signal). In order to make the resonance frequency of the bone conduction acoustic transmission device 800 within a specific frequency range (for example, 2000 Hz to 5000 Hz), the materials and thicknesses of the acoustic conversion unit 820 (for example, the first electrode layer 821, the second electrode layer 823, and the piezoelectric layer 822) and the vibration unit (for example, the support arm 830) may be adjusted. In some embodiments, the acoustic conversion unit 820 may include a bonding wire electrode layer (PAD layer). The bonding wire electrode layer may be located on the first electrode layer 821 and the second electrode layer 823, and by connecting the first electrode layer 821 and the second electrode layer 823 to an external circuit in the manner of an external bonding wire (for example, a gold wire, an aluminum wire, etc.), the voltage signal between the first electrode layer 821 and the second electrode layer 823 is output to a backend processing circuit. In some embodiments, the material of the bonding wire electrode layer may include copper foil, titanium, copper, etc. In some embodiments, the thickness of the bonding wire electrode layer may be 100 nm to 200 nm. Preferably, the thickness of the bonding wire electrode layer may be 150 nm to 200 nm.In some embodiments, the acoustic conversion unit 820 may further include a seed layer, and the seed layer may be located between the second electrode layer 823 and the support arm 830. In some embodiments, the material of the seed layer may be the same as the material of the piezoelectric layer 822. For example, if the material of the piezoelectric layer 822 is AlN, the material of the seed layer may also be AlN. In some embodiments, the material of the seed layer may be different from the material of the piezoelectric layer 822. Note that the specific frequency range of the resonance frequency of the bone conduction acoustic transmission device 800 is not limited to 2000 Hz to 5000 Hz, and may be 4000 Hz to 5000 Hz or 2300 Hz to 3300 Hz, etc., and the specific frequency range can be adjusted according to the actual situation. Also, when the mass element 840 protrudes upward with respect to the support arm 830, the acoustic conversion unit 820 may be located on the lower surface of the support arm 830, and the seed layer may be located between the mass element 840 and the support arm 830.

[0070] In some embodiments, the mass element 840 may 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 the structure of each layer, and the parameters may be the same as or different from those of the elastic layer of the support arm 830 and the acoustic conversion unit 820. In some embodiments, the shape of the mass element 840 may be a regular or irregular shape such as circular, semi-circular, elliptical, triangular, quadrilateral, pentagonal, hexagonal, heptagonal, octagonal, etc. In some embodiments, the thickness of the mass element 840 may be the same as or different from the total thickness of the support arm 830 and the acoustic conversion unit 820. Regarding the material and size when the mass element 840 is a multi-layer structure, reference can be made to the elastic layer of the support arm 830 and the acoustic conversion unit 820, and the description is omitted herein. Also, here, the material and parameters of each layer structure of the elastic layer and the acoustic conversion unit 820 may be applied to the bone conduction acoustic transmission device shown in FIGS. 1, 3, 4, 5, and 7.

[0071] In some embodiments, the acoustic conversion unit 820 may include at least an effective acoustic conversion unit. An effective acoustic conversion unit is a part of the structure of an acoustic conversion unit that finally outputs an electrical signal. For example, when the shapes and areas of the first electrode layer 821, the piezoelectric layer 822, and the second electrode layer 823 are all the same and the support arm 830 (elastic layer) is partially covered, the first electrode layer 821, the piezoelectric layer 822, and the second electrode layer 823 are effective acoustic conversion units. Also, for example, when the first electrode layer 821 and the piezoelectric layer 822 partially cover the support arm 830 and the second electrode layer 823 completely covers the support arm 830, the portion of the first electrode layer 821 corresponding to the first electrode layer 821 among the first electrode layer 821, the piezoelectric layer 822, and the second electrode layer 823 constitutes an effective acoustic conversion unit. Further, for example, when the first electrode layer 821 partially covers the support arm 830 and both the piezoelectric layer 822 and the second electrode layer 823 completely cover the support arm 830, the portion of the first electrode layer 821 corresponding to the first electrode layer 821 among the first electrode layer 821, the piezoelectric layer 822, and the portion of the second electrode layer 823 corresponding to the first electrode layer 821 constitute an effective acoustic conversion unit. Further, for example, when the first electrode layer 821, the piezoelectric layer 822, and the second electrode layer 823 completely cover the support arm 830, but the first electrode layer 821 is divided into a plurality of individual electrodes by providing an insulating channel (for example, the electrode insulating channel 8200) in the first electrode layer 821, the individual electrode portions that output electrical signals in the first electrode layer 821 and the corresponding piezoelectric layer 822 and the second electrode layer 823 portions are effective acoustic conversion units. The individual electrode regions in the first electrode layer 821 that do not output electrical signals, the individual electrodes in the first electrode layer 821 that do not output electrical signals and the piezoelectric layer 822 corresponding to the insulating channel, and the regions of the second electrode layer 823 do not provide electrical signals and mainly provide mechanical actions. In order to improve the signal-to-noise ratio of the bone conduction acoustic transmission device 800, the effective acoustic conversion unit may be installed at a location close to the mass element 840 of the support arm 830 or at a location close to the connection location between the support arm 830 and the base structure 810. Preferably, the effective acoustic conversion unit is installed at a position close to the mass element 840 of the support arm 830.In some embodiments, when an effective acoustic conversion unit is installed at a location close to the mass element 840 of the support arm 830 or at a location close to the connection location between the support arm 830 and the base structure 810, the ratio of the area of the support arm 830 covered by the effective acoustic conversion unit to the area of the support arm 830 is 5% - 40%. Preferably, the ratio of the area of the support arm 830 covered by the effective acoustic conversion unit to the area of the support arm 830 is 10% - 35%. More preferably, the ratio of the area of the support arm 830 covered by the effective acoustic conversion unit to the area of the support arm 830 is 15% - 20%.

[0072] The signal-to-noise ratio of the bone conduction acoustic transmission device 800 is positively correlated with the intensity of the output electrical signal. When the laminated structure moves relative to the base structure, the deformation stress at the connection location between the support arm 830 and the mass element 840 and at the connection location 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 intensity of the output voltage at the connection location between the support arm 830 and the mass element 840 and at the connection location between the support arm 830 and the base structure 810 is also greater than the intensity of the output voltage in the middle region of the support arm 830. In some embodiments, when the acoustic conversion unit 820 completely or almost completely covers the upper surface or the lower surface of the support arm 830, in order to improve the signal-to-noise ratio of the bone conduction acoustic transmission device 800, an electrode insulation channel 8200 may be installed in the first electrode layer 821. By dividing the first electrode layer 821 into two parts by the electrode insulation channel 8200, a 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 location between the support arm 830 and the base structure 810. The part that outputs the electrical signal and the corresponding piezoelectric layer 822 and the second electrode layer 823 among the two parts divided by the electrode insulation channel 8200 in the first electrode layer 821 are effective acoustic conversion units. In some embodiments, the electrode insulation channel 8200 may be a straight line extending along the width direction of the support arm 830. In some embodiments, the width of the electrode insulation channel 8200 may be 2μm - 20μm. Preferably, the width of the electrode insulation channel 8200 may be 4μm - 10μm.

[0073] Note that the electrode insulation channel 8200 is not limited to a straight line extending along the width direction of the support arm 830, and may be a curve, a bent line, a wavy line, or the like. Further, the electrode insulation channel 8200, for example, the electrode insulation channel 8201 shown in FIG. 10, does not have to extend along the width direction of the support arm 830. The electrode insulation channel 8200 only needs to be able to divide the acoustic conversion unit 820 into a plurality of parts, and will not be further limited herein.

[0074] As shown in FIG. 10, when a part of the structure of the acoustic conversion unit 820 (for example, the acoustic conversion unit between the electrode insulating channel 8201 and the mass element 840 in FIG. 10) is installed 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 may further include an electrode lead. Taking the first electrode layer 821 as an example, the electrode insulating channel 8201 divides the first electrode layer 821 into two parts. A 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 location between the support arm 830 and the base structure 810. In order to output a voltage close to the mass element 840 of the acoustic conversion unit 820, a part of the region (the region located at the edge of the support arm 830 in the first electrode layer 821 shown in the figure) may be divided from the first electrode layer 821 close to the connection location between the support arm 830 and the base structure 810 by the electrode insulating channel 8201, and this part of the region electrically connects the part connected to the mass element 840 of the acoustic conversion unit 820 or the part close to the mass element 840 to the processing unit of the bone conduction acoustic transmission device 800. In some embodiments, the width of the electrode lead may be 4 μm to 20 μm. Preferably, the width of the electrode lead may be 4 μm to 10 μm. In some embodiments, the electrode lead may be located at any position in the width direction of the support arm 830. For example, the electrode lead may be located at the center of the support arm 830 or at a position close to the edge in the width direction. Preferably, the electrode lead may be located at a position close to the edge in the width direction of the support arm 830. By installing the electrode lead 8211, the use of conductive wires in the acoustic conversion unit 820 can be avoided, the structure can be simplified, and subsequent manufacturing and assembly can be facilitated.

[0075] Considering that the surface of the piezoelectric material of the piezoelectric layer 822 may be roughened by etching in a region close to the edge of the support arm 830, which may reduce the quality of the piezoelectric material, in some embodiments, when the area of the piezoelectric layer 822 is the same as the area of the second electrode layer 823, in order for the first electrode layer 821 to be located within a region of high-quality piezoelectric material, by making the area of the piezoelectric layer 822 smaller than the area of the first electrode layer 821, the edge region of the first electrode layer 821 avoids the edge region of the piezoelectric layer 822, and an electrode contraction channel (not shown) is formed between the first electrode layer 821 and the piezoelectric layer 822. By providing the electrode contraction channel, the first electrode layer 821 and the second electrode layer 823 avoid the region with low quality at the edge of the piezoelectric layer 822, and as a result, the signal-to-noise ratio of the bone conduction acoustic transmission device can be improved. In some embodiments, the width of the electrode contraction channel may be 2 μm to 20 μm. Preferably, the width of the electrode contraction channel may be 2 μm to 10 μm.

[0076] As shown in FIG. 10, taking the case where the mass element 840 protrudes downward with respect to the support arm 830 as an example, the acoustic conversion unit 820 may further include an extending region 8210 extending along the longitudinal direction of the support arm 830, and the extending region 8210 is located on the upper surface of the mass element 840. In some embodiments, an electrode insulation channel 8201 is provided at the edge position of the extending region 8210 located on the upper surface of the mass element 840, so as to prevent the problem of excessive stress concentration on the support arm 830 and improve the stability of the support arm 830. In some embodiments, the length of the extending region 8210 is greater than the width of the support arm 830. Here, the length of the extending region 8210 corresponds to the width along the support arm 830. In some embodiments, the length of the extending region 8210 is 4 μm to 30 μm. Preferably, the length of the extending region 8210 is 4 μm to 15 μm. In some embodiments, the length of the extending region 8210 in the mass element 840 is 1.2 times to 2 times the width of the connection portion between the support arm 830 and the edge of the mass element 840. Preferably, the length of the extending region 8210 in the mass element 840 is 1.2 times to 1.5 times the width of the connection portion between the support arm 830 and the edge of the mass element 840.

[0077] FIG. 11 is a schematic configuration diagram of a bone conduction acoustic transmission device according to some embodiments of the present application. The overall structure of the bone conduction acoustic transmission device 1000 shown in FIG. 11 is substantially the same as the overall structure of the bone conduction acoustic transmission device 800 shown in FIG. 8, but differs in that the shape of the support arm is different. As shown in FIG. 11, the base structure 1010 has a rectangular parallelepiped frame structure. In some embodiments, the interior of the base structure 1010 may include a hollow portion for suspending the acoustic conversion unit and the vibration unit. In some embodiments, the shape of the hollow portion may be other regular or irregular shapes such as circular, quadrilateral (e.g., rectangular, parallelogram), pentagonal, hexagonal, heptagonal, octagonal, etc. In some embodiments, the vibration unit may include four support arms 1030 and a mass element 1040. One end of the four support arms 1030 is connected to the upper surface, lower surface, or the side wall where the hollow portion of the base structure 1010 is located, and the other end is connected to the upper surface, lower surface, or the circumferential side wall of the mass element 1040. In some embodiments, the mass element 1040 may protrude upward and / or downward with respect to the support arm 1030. For example, when the ends of the four support arms 1030 are connected to the upper surface of the mass element 1040, the mass element 1040 may protrude downward with respect to the support arm 1030. Also, for example, when the ends of the four support arms 1030 are connected to the lower surface of the mass element 1040, the mass element 1040 may protrude upward with respect to the support arm 1030. Further, for example, when the ends of the four support arms 1030 are connected to the circumferential side wall of the mass element 1040, the mass element 1040 may protrude upward and downward with respect to the support arm 1030. In some embodiments, the shape of the support arm 1030 is rectangular, and one end of the support arm 1030 is connected to the mass element 1040 and the other end is connected to the base structure 1010.

[0078] In some embodiments, in order to improve the signal-to-noise ratio of the bone conduction acoustic transmission device 1000, an effective acoustic conversion unit may be installed at a location close to the mass element 1040 of the support arm 1030 or at a location close to the connection location between the support arm 1030 and the base structure 1010. Preferably, the effective acoustic conversion unit is installed at a position close to the mass element 1040 of the support arm 1030. In some embodiments, when the effective acoustic conversion unit is installed at a location close to the mass element 1040 of the support arm 1030 or at a location close to the connection location between the support arm 1030 and the base structure 1010, the ratio of the area of the support arm 1030 covered by the effective acoustic conversion unit to the area of the support arm 1030 is 5% to 40%. Preferably, the ratio of the area of the support arm 1030 covered by the effective acoustic conversion unit to the area of the support arm 1030 is 10% to 35%. More preferably, the ratio of the area of the support arm 1030 covered by the effective acoustic conversion unit 1020 to the area of the support arm 1030 is 15% to 20%.

[0079] The signal-to-noise ratio of the bone conduction acoustic transmission device 1000 is positively correlated with the intensity of the output electrical signal. When the laminated structure moves relative to the base structure, the deformation stress at the connection between the support arm 1030 and the mass element 1040 and the connection between the support arm 1030 and the base structure 1010 is greater than the deformation stress in the middle region of the support arm 1030. Accordingly, the intensity of the output voltage at the connection between the support arm 1030 and the mass element 1040 and the connection between the support arm 1030 and the base structure 1010 is also greater than the intensity of the output voltage in the middle region of the support arm 1030. In some embodiments, when the acoustic conversion unit completely or almost completely covers the upper or lower surface of the support arm 1030, an electrode insulating channel 1050 may be provided in the first electrode layer to improve the signal-to-noise ratio of the bone conduction acoustic transmission device 1000. By dividing the first electrode layer into two parts by the electrode insulating channel 1050, a part of the first electrode layer is close to the mass element 1040, and the other part of the first electrode layer is close to the connection between the support arm 1030 and the base structure 1010. In some embodiments, the electrode insulating channel 1050 may be a straight line extending along the width direction of the support arm 1030. In some embodiments, the width of the electrode insulating channel 1050 may be 2 μm to 20 μm. Preferably, the width of the electrode insulating channel 1050 may be 4 μm to 10 μm.

[0080] Note that the electrode insulating channel 1050 is not limited to a straight line extending along the width direction of the support arm 1030, and may be a curve, a bent line, a wavy line, etc. Also, the electrode insulating channel 1050, for example, the electrode insulating channel 11200 shown in FIG. 12, does not have to extend along the width direction of the support arm 1030. As long as the electrode insulating channel can divide the acoustic conversion unit into a plurality of parts, it will not be further limited in this specification.

[0081] As shown in FIG. 12, when a part of the structure of the acoustic conversion unit (for example, the acoustic conversion unit between the electrode insulation channel 11200 and the mass element 1140 in FIG. 12) is installed at a position close to the mass element 1140 of the support arm 1130, the first electrode layer 1121 and / or the second electrode layer may further include an electrode lead. Taking the first electrode layer 1121 as an example, the electrode insulation channel 11200 divides the first electrode layer 1121 into two parts. A part of the first electrode layer 1121 is connected to or close to the mass element 1140, and the other part of the first electrode layer 1121 is close to the connection location between the support arm 1130 and the base structure 1110. In order to output a voltage close to the mass element 1140 of the acoustic conversion unit, a part of the region (the region located at the edge of the support arm 1130 in the first electrode layer 1121 shown in the figure) may be divided from the first electrode layer 1121 close to the connection location between the support arm 1130 and the base structure 1110 by the electrode insulation channel 11200, and this part of the region electrically connects the part connected to or close to the mass element 1140 in the acoustic conversion unit to the processing unit of the bone conduction acoustic transmission device. In some embodiments, the width of the electrode lead may be 4 μm to 20 μm. Preferably, the width of the electrode lead may be 4 μm to 10 μm. In some embodiments, the electrode lead may be located at any position in the width direction of the support arm 1130. For example, the electrode lead may be located at the center of the support arm 1130 or close to the edge in the width direction. Preferably, the electrode lead may be located at a position close to the edge in the width direction of the support arm 1130. By installing the electrode lead, the use of conductive wires in the acoustic conversion unit can be avoided, the structure can be simplified, and subsequent manufacturing and assembly can be facilitated.

[0082] As shown in FIG. 13, in a region close to the edge of the support arm, the surface of the piezoelectric material of the piezoelectric layer is roughened by etching, reducing the quality of the piezoelectric material. In some embodiments, when the area of the piezoelectric layer is the same as the area of the second electrode layer, since the first electrode layer 1121 is located within the region of the piezoelectric material with high quality of the piezoelectric layer, by making the area of the piezoelectric layer smaller than the area of the first electrode layer 1121, the edge region of the first electrode layer 1121 avoids the edge region of the piezoelectric layer, and an electrode contraction channel 11212 is formed between the first electrode layer 1121 and the piezoelectric layer. By providing the electrode contraction channel 11212, the first electrode layer and the second electrode layer avoid the region with low quality at the edge of the piezoelectric layer. As a result, the signal-to-noise ratio of the bone conduction acoustic transmission device can be improved. In some embodiments, the width of the electrode contraction channel 11212 may be 2 μm to 20 μm. Preferably, the width of the electrode contraction channel 11212 may be 2 μm to 10 μm.

[0083] As shown in FIG. 14, in some embodiments, taking the case where the mass element 1140 protrudes downward with respect to the support arm 1130 as an example, the acoustic conversion unit may further include an extending region 11210 extending along the longitudinal direction of the support arm 1130, and the extending region 11210 is located on the upper surface of the mass element 1140. In some embodiments, an electrode insulating channel 11200 is installed at the edge position of the extending region 11210 located on the upper surface of the mass element 1140, so as to prevent the problem of excessive stress concentration on the support arm 1130 and improve the stability of the support arm 1130. In some embodiments, the length of the extending region 11210 is greater than the width of the support arm 1130. Here, the length of the extending region 11210 corresponds to the width of the support arm 1130. In some embodiments, the length of the extending region 11210 is 4 μm to 30 μm. Preferably, the length of the extending region 11210 is 4 μm to 15 μm. In some embodiments, the length of the extending region 11210 in the mass element 1140 is 1.2 times to 2 times the width of the connection portion between the support arm 1130 and the edge of the mass element 1140. Preferably, the length of the extending region 11210 in the mass element 1140 is 1.2 times to 1.5 times the width of the connection portion between the support arm 1130 and the edge of the mass element 1140. For the parameters such as the materials and sizes of the structures of the acoustic conversion unit, the first electrode layer, the second electrode layer, the piezoelectric layer, the vibration unit, the mass element 1140, etc. in this embodiment, reference can be made to the contents of FIGS. 8 to 10, and the description is omitted in this specification.

[0084] FIG. 15 is a schematic configuration diagram of another bone conduction acoustic transmission device according to some embodiments of the present application. The structure of the bone conduction acoustic transmission device 1500 shown in FIG. 15 is substantially the same as the structure of the bone conduction acoustic transmission device 800 shown in FIG. 8, but differs in that the connection method between the support arm and the base structure is different. As shown in FIG. 15, the base structure 1510 has a rectangular parallelepiped frame structure. In some embodiments, the interior of the base structure 1510 may include a hollow portion for suspending the acoustic conversion unit and the vibration unit. In some embodiments, the vibration unit may include four support arms 1530 and a mass element 1540. One end of the four support arms 1530 is connected to the upper surface, lower surface, or the side wall where the hollow portion of the base structure 1510 is located, and the other end is connected to the upper surface, lower surface, or the circumferential side wall of the mass element 1540. In some embodiments, the mass element 1540 may protrude upward and / or downward with respect to the support arm 1530. For example, when the ends of the four support arms 1530 are connected to the upper surface of the mass element 1540, the mass element 1540 may protrude downward with respect to the support arm 1530. Also, for example, when the ends of the four support arms 1530 are connected to the lower surface of the mass element 1540, the mass element 1540 may protrude upward with respect to the support arm 1530. Further, for example, when the ends of the four support arms 1530 are connected to the circumferential side wall of the mass element 1540, the mass element 1540 may protrude upward and downward with respect to the support arm 1530. In some embodiments, the shape of the support arm 1530 is trapezoidal, the end with the larger width of the support arm 1530 is connected to the mass element 1540, and the end with the smaller width of the support arm 1530 is connected to the base structure 1510. Note that parameters such as the structure, size, and thickness of members such as the acoustic conversion unit 820, the first electrode layer 821, the second electrode layer 823, the piezoelectric layer 822, the vibration unit, the mass element 840, the extending region 8210, the electrode insulating channel 8201, the electrode contraction channel, and the electrode insulating channel 8200 in FIGS. 8 to 10 can be applied to the bone conduction acoustic transmission device 1500, and will not be further described in this specification.

[0085] FIG. 16 is a schematic configuration diagram of a bone conduction acoustic transmission device according to some embodiments of the present application. The structure of the bone conduction acoustic transmission device 1600 shown in FIG. 16 is substantially the same as the structure of the bone conduction acoustic transmission device 800 shown in FIG. 8, but is different in that the structure of the support arm 1630 of the bone conduction acoustic transmission device 1600 is different from the structure of the support arm 830 of the bone conduction acoustic transmission device 800. In some embodiments, the interior of the base structure 1610 may include a hollow portion for suspending the acoustic conversion unit and the vibration unit. In some embodiments, the vibration unit may include four support arms 1630 and a mass element 1640. One end of the four support arms 1630 is connected to the upper surface, lower surface, or the side wall where the hollow portion of the base structure 1610 is located, and the other end is connected to the upper surface, lower surface, or the circumferential side wall of the mass element 1640. In some embodiments, the mass element 1640 may protrude upward and / or downward with respect to the support arm 1630. For example, when the ends of the four support arms 1630 are connected to the upper surface of the mass element 1640, the mass element 1640 may protrude downward with respect to the support arm 1630. Also, for example, when the ends of the four support arms 1630 are connected to the lower surface of the mass element 1640, the mass element 1640 may protrude upward with respect to the support arm 1630. Further, for example, when the ends of the four support arms 1630 are connected to the circumferential side wall of the mass element 1640, the mass element 840 may protrude upward and downward with respect to the support arm 1630. In some embodiments, the upper surface of the mass element 1640 is in the same horizontal plane as the upper surface of the support arm 1630, and / or the lower surface of the mass element 1640 is in the same horizontal plane as the lower surface of the support arm 1630. In some embodiments, the shape of the support arm 1630 may be a substantially L-shaped structure. As shown in FIG. 16, the support arm 1630 may include a first support arm 1631 and a second support arm 1632. One end of the first support arm 1631 is connected to one end of the second support arm 1632, and the first support arm 1631 and the second support arm 1632 have a certain included angle. In some embodiments, the range of the included angle is 75° to 105°.In some embodiments, the end of the first support arm 1631 that is away from the connection point between the first support arm 1631 and the second support arm 1632 is connected to the base structure 1610, and the end of the second support arm 1632 that is away from the connection point between the first support arm 1631 and the second support arm 1632 is connected to the upper surface, lower surface, or circumferential side wall of the mass element 1640. Thus, the mass element 1640 is installed in a suspended manner in the hollow portion of the base structure 1610.

[0086] In some embodiments, the acoustic conversion unit has a multilayer structure and may include structures such as a first electrode layer, a second electrode layer, a piezoelectric layer, an elastic layer, a seed layer, an electrode contraction channel, and an electrode insulation channel. For each layer structure of the acoustic conversion unit, the mass element 1640, etc., reference can be made to the descriptions of the acoustic conversion unit 820, the first electrode layer 821, the second electrode layer 823, the piezoelectric layer 822, the vibration unit, the mass element 840, the extending region 8210, the electrode insulation channel 8201, the electrode contraction channel, and the electrode insulation channel 8200 in FIGS. 8 to 10 of the specification of the present application, and no further description will be given herein.

[0087] In some embodiments, in the bone conduction acoustic transmission device described in any one of the above embodiments, a position limiting structure (not shown) may be further included, and the position limiting structure has a plate-like structure. In some embodiments, the position limiting structure may be located in the hollow portion of the base structure. The position limiting structure may be located above or below the laminated structure and may be installed facing the laminated structure. In some embodiments, when the base structure is a structure that penetrates vertically, the position limiting structure may be located at the top or bottom of the base structure. The position limiting structure and the mass element of the laminated structure are installed at an interval. When receiving a large impact, the position limiting structure limits the amplitude of the mass element of the laminated structure, thereby avoiding damage to the device due to intense vibration. In some embodiments, the position limiting structure may be a rigid structure (e.g., a position limiting block), or a structure having a certain elasticity (e.g., an elastic cushion, a beam with a buffer piece, or a structure in which a buffer support arm and a position limiting block are installed simultaneously).

[0088] The laminated structure has a natural frequency. When the frequency of an external vibration signal is close to the natural frequency, the laminated structure generates a large amplitude and outputs a large electrical signal. Therefore, the response of the bone conduction acoustic transmission device to external vibrations is expressed as having a resonance peak near the natural frequency. In some embodiments, by changing the parameters of the laminated structure to move the natural frequency of the laminated structure within the voice band range, the resonance peak of the bone conduction acoustic transmission device can be brought within the voice band range, and the response sensitivity of the bone conduction acoustic transmission device to vibrations in the voice band (for example, the frequency range before the resonance peak) can be improved. As shown in FIG. 17, the frequency corresponding to the resonance peak 1701 in the frequency response curve (the solid curve in FIG. 17) where the natural frequency of the laminated structure is advanced is smaller than the frequency corresponding to the resonance peak 1702 in the frequency response curve (the dashed curve in FIG. 17) where the natural frequency of the laminated structure is not changed. For an external vibration signal whose frequency is smaller than the frequency where the resonance peak 1701 is located, the bone conduction acoustic transmission device corresponding to the solid curve has higher sensitivity.

[0089] The displacement output formula of the laminated structure is as follows.

[0090]

Number

[0091] In the formula, M is the mass of the laminated structure, R is the attenuation of the laminated structure, K is the elastic coefficient of the laminated structure, F is the amplitude of the driving force, and x a is the displacement of the laminated structure, w is the angular frequency of the external force, and w0 is the natural frequency of the laminated structure. When the angular frequency

Number

[0092] As the resonance peak shifts forward, a peak value appears in the voice band. When the bone conduction acoustic transmission device picks up a signal, there are too many signals in the resonance peak band, which reduces the call effect. In some embodiments, in order to improve the quality of the voice signal collected by the bone conduction acoustic transmission device, a damping structure layer may be provided on the laminated structure, and the damping structure layer can increase the energy loss of the laminated structure during vibration, especially the loss in the resonance frequency band. Here, the damping coefficient is explained as follows using the reciprocal 1 / Q of the mechanical quality factor.

[0093]

Equation

[0094] In the formula, Q -1 is the reciprocal of the quality factor, also called the structural loss factor η, Δf is the frequency difference value f1 - f2 (also called the 3dB bandwidth) at half of the resonance amplitude, and f0 is the resonance frequency.

[0095] The relationship between the loss factor η of the laminated structure and the loss factor tanδ of the damping material is as follows.

[0096]

Equation

[0097] In the formula, X is a shear parameter and is related to the thickness and material properties of each layer of the laminated structure. Y is a stiffness parameter and is related to the thickness and Young's modulus of each layer of the laminated structure.

[0098] As can be seen from equations (2) and (3), by adjusting the material of the damping structure layer and the materials of each layer of the laminated structure, the loss factor η of the laminated structure can be adjusted to an appropriate 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 varies under different stress (deformation) states. For example, the damping is large when the stress is high or the amplitude is large. Therefore, based on the characteristics that the laminated structure has a small amplitude in the non-resonant region and a large amplitude in the resonant region, by increasing the damping structure layer, it is ensured that the sensitivity of the bone conduction acoustic transmission device in the non-resonant region is not decreased, the Q value in the resonant region is decreased, and the frequency response of the bone conduction acoustic transmission device can be flattened over the entire frequency band. FIG. 18 is a frequency response curve diagram of a bone conduction acoustic transmission device having a damping structure layer and a bone conduction acoustic transmission device not having a damping structure layer according to some embodiments of the present application. As shown in FIG. 18, the frequency response curve 1802 of the electrical signal output by the bone conduction acoustic transmission device having a damping structure layer is flatter than the frequency response curve 1801 of the electrical signal output by the bone conduction acoustic transmission device without the damping structure layer installed.

[0099] In some embodiments, the bone conduction acoustic transmission device may include at least one layer of damping structure layer, and the peripheral side of the at least one layer of damping structure layer may be connected to the base structure. In some embodiments, the at least one layer of damping structure layer may be located on the upper surface and / or the lower surface of the laminated structure, or between the multi-layered structures of the laminated structure. In some embodiments, for the macro-sized laminated structure and the base structure, the damping structure layer may be directly adhered to the surface of the base structure or the laminated structure. In some embodiments, for the MEMS device, the damping structure layer may be connected to the laminated structure and the base structure by means of a semiconductor process, such as vapor deposition, spin coating, microassembly, etc. In some embodiments, the shape of the damping structure layer may be a regular shape such as circular, elliptical, triangular, square, hexagonal, octagonal, etc. In some embodiments, by selecting the material, size, thickness, etc. of the damping film, the output effect of the electrical signal of the bone conduction acoustic transmission device can be improved.

[0100] To more clearly explain the damping structure layer, a cantilever beam type bone conduction acoustic transmission device (for example, the bone conduction acoustic transmission device 100 shown in FIG. 1, the bone conduction acoustic transmission device 300 shown in FIG. 3, the bone conduction acoustic transmission device 400 shown in FIG. 4) will be exemplarily described. FIG. 19 is a cross-sectional view of a bone conduction acoustic transmission device according to some embodiments of the present application. As shown in FIG. 19, the bone conduction acoustic transmission device 1900 may include a base structure 1910, a laminated structure 1920, and a damping structure layer 1930. Further, one end of the laminated structure 1920 is connected to the upper surface of the base structure 1910, and the other end is installed in a suspended manner in the hollow portion of the base structure 1910, and the damping structure layer 1930 is located on the upper surface of the laminated structure 1920. The area of the damping structure layer 1930 may be larger than the area of the laminated structure 1920, that is, the damping structure layer 1930 can not only cover the upper surface of the laminated structure 1920, but also cover the gap between the laminated structure 1920 and the base structure 1910. In some embodiments, at least a part of the peripheral side of the damping structure layer 1930 may be fixed to the base structure 1910.

[0101] FIG. 20 is a cross-sectional view of a bone conduction acoustic transmission device according to some embodiments of the present application. As shown in FIG. 20, the bone conduction acoustic transmission device 2000 may include a base structure 2010, a laminated structure 2020, and two damping structure layers, and the two damping structure layers include a first damping structure layer 2030 and a second damping structure layer 2040. Further, the second damping structure layer 2040 is connected to the upper surface of the base structure 2010, the lower surface of the laminated structure 2020 is connected to the upper surface of the second damping structure layer 2040, one end of the laminated structure 2020 is installed in the hollow portion of the base structure 2010 in a suspended manner, and the first damping structure layer 2030 is connected to the upper surface of the laminated structure 2020. The area of the first damping structure layer 2030 and / or the second damping structure layer 2040 is larger than the area of the laminated structure 2020.

[0102] FIG. 21 is a cross-sectional view of a bone conduction acoustic transmission device according to some embodiments of the present application. As shown in FIG. 21, the bone conduction acoustic transmission device 2100 may include a base structure 2110, a laminated structure 2120, and a damping structure layer 2130. Further, the damping structure layer 2130 is located on the lower surface of the base structure 2110. The laminated structure 2120 has its lower surface connected to the upper surface of the damping structure layer 2130, and one end is installed in the hollow portion of the base structure 2110 in a suspended manner.

[0103] Note that the position of the damping structure layer (for example, the damping structure layer 1930) is not limited to the upper surface and / or the lower surface of the laminated structure shown in FIGS. 19 to 21 above, and it may be located between the multilayered structures of the laminated structure. For example, the damping structure layer may be located between an elastic layer and a first electrode layer. Also, for example, the damping structure layer may be located between a first elastic layer and a second elastic layer. Further, the damping structure layer is not limited to the above cantilever beam type bone conduction acoustic transmission device, and may be applied to the bone conduction acoustic transmission devices shown in FIGS. 5, 7, 8, 11, 15, and 16, and the description thereof is omitted herein.

[0104] Although the basic concepts have been described above, it is clear to those skilled in the art that the above detailed disclosure is merely presented as an example and does not limit the present application. Although not explicitly described in this specification, those skilled in the art can make various changes, improvements, and modifications to the present application. Since these changes, improvements, and modifications are intended to be suggested by the present application, they are within the spirit and scope of the exemplary embodiments of the present application.

[0105] In addition, specific terms are used in the present application to describe the embodiments. For example, "one embodiment", "an embodiment", and / or "some embodiments" mean specific features, structures, or characteristics related to at least one embodiment of the present application. Therefore, it should be emphasized and understood that the more than two mentions of "an embodiment", "one embodiment", or "one alternative embodiment" in various parts of this specification do not necessarily all refer to the same embodiment. Also, the specific features, structures, or characteristics in one or more embodiments of the present application may be appropriately combined.

[0106] Furthermore, as will be understood by those skilled in the art, each aspect of the present application can be exemplified and described in several patentable classes or contexts, including any novel and useful process, machine, product, or combination of substances, or any novel and useful improvement thereto. Thus, each aspect of the present application may be implemented entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. Any of the above hardware or software may also be referred to as a "data block", "module", "engine", "unit", "assembly", or "system". Additionally, each aspect of the present application can take the form of a computer program product embodied in one or more computer-readable media containing computer-readable program code.

[0107] Furthermore, unless expressly recited in the claims, the recited order of processing elements or sequences, the use of alphanumerics, or the use of other names in this application does not limit the order of the procedures and methods of this application. In the above disclosure, various useful examples of the invention that are currently considered are described through various examples, but such details are for illustrative purposes only. The appended claims are not limited to the disclosed examples, but rather are intended to cover all modifications and equivalent combinations within the spirit and scope of the examples of this application. For example, the system assembly described above may be implemented by a hardware device, but may also be implemented by a software-only solution, such as installing the system described in an existing processing device or mobile device.

[0108] Similarly, in the foregoing description of the examples of this application, it will be understood that for the purpose of simplifying the disclosure of this application and assisting in the understanding of one or more examples of the invention, various features may be grouped together in one example, drawing, or description thereof. However, such a disclosure method should not be construed as reflecting an intention that the claimed subject matter requires more features than are recited in each claim. In fact, the features of the examples are fewer than all the features of the single example disclosed above.

[0109] In some embodiments, numbers are used to describe the number of components and attributes. The numbers used to describe such embodiments should be understood as being modified by the modifier "about", "substantially" or "essentially" in some examples. Unless otherwise specified, "about", "substantially" or "essentially" indicates that a variation of ±20% of the value described by the above numbers is allowed. Therefore, in some embodiments, the numerical parameters used in the specification and claims are all approximate values that can vary according to the characteristics required for a specific embodiment. In some embodiments, for numerical parameters, the specified number of significant digits should be considered and the usual rounding method should be adopted. Although the numerical ranges and parameters for determining the scope in some embodiments of the present application are approximate values, in specific embodiments, such numerical values are set as accurately as possible.

[0110] All patents, patent applications, published patent gazettes, and other materials such as papers, books, specifications, publications, documents, etc. referred to in the present application are incorporated herein by reference in their entirety, except for application process documents that do not match or conflict with the content of the present application, and documents that may have a limiting effect on the broadest scope of the claims of the present application (currently or later related to the present application). In addition, if the descriptions, definitions, and / or uses of terms in the attached materials of the present application do not match or conflict with the content described in the present application, the descriptions, definitions, and / or uses of terms in the present application shall take precedence.

[0111] Finally, it should be understood that the embodiments described in the present application are merely for explaining the principles of the embodiments of the present application. Other variations may also be within the scope of the present application. Therefore, without limitation, by way of example, alternative configurations of the embodiments of the present application may be considered to be in accordance with the teachings of the present application. Therefore, the embodiments of the present application are not limited to the embodiments clearly introduced and described in the present application.

Description of Reference Numerals

[0112] 100, 300, 400, 500, 700, 800, 1000 Bone Conduction Acoustic Transmission Device 110, 310, 410, 510, 710, 810 Substrate structures 120, 320, 420, 520, 720, 820 Acoustic conversion units 130, 330, 430 Vibration units 140 Connection base 131 First elastic layer 132 Second elastic layer 121, 521 First electrode layer 122, 322, 423, 522 Piezoelectric layer 123, 523 Second electrode layer 321, 421 First electrode 422 Second electrode 4210 First comb-shaped structure 4220 Second comb-shaped structure 530, 730 Suspension film structures 5300 Hole 740, 840, 1640 Mass elements 830 Support arm 8200, 8201 Electrode insulation channels 8211 Electrode lead 8210 Extending region 1920 Stacked structure 1930 Damping structure layer

Claims

1. A bone conduction acoustic transmission device, a laminated structure formed by a vibration unit and an acoustic conversion unit, a base structure configured to place the laminated structure thereon and physically connected to at least one side of the laminated structure, comprising, the base structure generates vibration by an external vibration signal, the vibration unit deforms in response to the vibration of the base structure, and the acoustic conversion unit generates an electrical signal based on the deformation of the vibration unit, the base structure includes a hollow frame structure inside, the width of the laminated structure in the bone conduction acoustic transmission device gradually decreases from the free end of the laminated structure toward the fixed end of the laminated structure, the fixed end of the laminated structure is connected to the base structure, and the free end of the laminated structure is installed suspended in the hollow portion of the hollow frame structure, characterized in that it is a bone conduction acoustic transmission device.

2. the vibration unit includes at least one elastic layer, the acoustic conversion unit includes at least a first electrode layer, a piezoelectric layer, and a second electrode layer installed in order from top to bottom, and the at least one elastic layer is located on the upper surface of the first electrode layer or the lower surface of the second electrode layer, the bone conduction acoustic transmission device according to claim 1.

3. the acoustic conversion unit further includes a seed layer, and the seed layer is located on the lower surface of the second electrode layer, the bone conduction acoustic transmission device according to claim 2.

4. the vibration unit includes at least one elastic layer, the acoustic conversion unit includes at least an electrode layer and a piezoelectric layer, and the at least one elastic layer is located on the surface of the electrode layer, the bone conduction acoustic transmission device according to claim 1.

5. The electrode layer includes a first electrode and a second electrode. The first electrode is bent into a first comb-shaped structure, and the second electrode is bent into a second comb-shaped structure. The first comb-shaped structure meshes with the second comb-shaped structure to form the electrode layer, and the electrode layer is located on the upper surface or the lower surface of the piezoelectric layer. The bone conduction acoustic transmission device according to claim 4, characterized in that.

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