CN116939447A

CN116939447A - Acoustic output device

Info

Publication number: CN116939447A
Application number: CN202210361079.5A
Authority: CN
Inventors: 朱光远; 张磊; 齐心
Original assignee: Shenzhen Voxtech Co Ltd
Current assignee: Shenzhen Voxtech Co Ltd
Priority date: 2022-04-07
Filing date: 2022-04-07
Publication date: 2023-10-24
Also published as: TW202341753A

Abstract

One or more embodiments of the present specification relate to an acoustic output device including: a piezoelectric element for converting an electric signal into mechanical vibration; an elastic element comprising a plurality of bar structures, each bar structure comprising one or more bending regions; and the mass element is connected with the piezoelectric element through the elastic element and receives mechanical vibration to generate an acoustic signal, wherein the rod structures are positioned in the same plane perpendicular to the vibration direction of the mass element, and the projection of the rod structures along the vibration direction of the mass element has two symmetrical axes perpendicular to each other. According to the embodiment of the specification, the shape and the structure of the elastic element in the acoustic output device are arranged, so that the elastic element can provide opposite rotation shear stress on a plane perpendicular to the vibration direction of the mass element, and therefore the rotation mode generated by rotation of the mass element and/or the piezoelectric element in the plane is restrained, and the resonance valley generated by the rotation mode in the frequency response curve of the acoustic output device is improved.

Description

Acoustic output device

Technical Field

The application relates to the technical field of acoustics, in particular to an acoustic output device.

Background

The piezoelectric speaker generally utilizes the inverse piezoelectric effect of the piezoelectric ceramic material to generate vibration so as to radiate sound waves outwards, and compared with the transmission electromagnetic speaker, the piezoelectric speaker has the advantages of high electromechanical transduction efficiency, low energy consumption, small volume, high integration level and the like, and has extremely wide prospect and future under the trend of miniaturization and integration of the current devices. However, compared to the conventional electromagnetic speaker, the piezoelectric speaker may have poor low-frequency sound quality due to poor low-frequency response of the piezoelectric acoustic device. Meanwhile, piezoelectric speakers have more vibration modes in the audible range, which also results in the inability to form a relatively flat frequency response curve.

Accordingly, there is a need for an acoustic output device that reduces vibrational modes in the audible range while also improving the low frequency response of the acoustic output device.

Disclosure of Invention

The embodiments of the specification provide an acoustic output device comprising a piezoelectric element for converting an electrical signal into mechanical vibrations; a resilient element comprising a plurality of bar structures, each bar structure comprising one or more bending regions; and the mass element is connected with the piezoelectric element through the elastic element and receives the mechanical vibration to generate an acoustic signal, wherein the rod structures are positioned in the same plane perpendicular to the vibration direction of the mass element, and the projection of the rod structures along the vibration direction of the mass element has two symmetrical axes which are perpendicular to each other.

Drawings

The application will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. The embodiments are not limiting, in which like numerals represent like structures, wherein:

FIG. 1 is an exemplary block diagram of an acoustic output device shown in accordance with some embodiments of the present description;

FIG. 2 is an exemplary block diagram of a resilient element shown in accordance with some embodiments of the present disclosure;

FIG. 3 is an exemplary block diagram of a resilient element shown in accordance with some embodiments of the present disclosure;

FIG. 4 is an exemplary block diagram of a resilient element shown in accordance with some embodiments of the present description;

FIG. 5 is an exemplary block diagram of a resilient element shown in accordance with some embodiments of the present disclosure;

FIG. 6 is a plot of the frequency response of an acoustic output device according to some embodiments of the present disclosure;

FIG. 7A is an exemplary block diagram of a resilient element shown in accordance with some embodiments of the present disclosure;

FIG. 7B is an exemplary block diagram of a resilient element shown in accordance with some embodiments of the present disclosure;

FIG. 7C is a plot of the frequency response of an acoustic output device according to some embodiments of the present disclosure;

FIG. 8A is an exemplary block diagram of a resilient element shown according to some embodiments of the present disclosure;

FIG. 8B is an exemplary block diagram of a resilient element shown according to some embodiments of the present disclosure;

FIG. 9 is an exemplary block diagram of an acoustic output device shown in accordance with some embodiments of the present description;

FIG. 10 is a plot of the frequency response of an acoustic output device according to some embodiments of the present disclosure;

FIG. 11A is an exemplary block diagram of an acoustic output device shown in accordance with some embodiments of the present description;

FIG. 11B is a plot of the frequency response of an acoustic output device according to some embodiments of the present disclosure;

FIG. 12 is an exemplary block diagram of an acoustic output device shown in accordance with some embodiments of the present description;

FIG. 13 is a plot of the frequency response of an acoustic output device shown in accordance with some embodiments of the present description;

FIG. 14 is an exemplary block diagram of an acoustic output device shown in accordance with some embodiments of the present description;

FIG. 15 is a plot of the frequency response of an acoustic output device according to some embodiments of the present disclosure;

FIG. 16 is an exemplary block diagram of an acoustic output device shown in accordance with some embodiments of the present description;

FIG. 17 is a plot of the frequency response of an acoustic output device shown in accordance with some embodiments of the present description;

FIG. 18 is a plot of the frequency response of an acoustic output device shown in accordance with some embodiments of the present disclosure;

FIG. 19 is an exemplary block diagram of an acoustic output device shown in accordance with some embodiments of the present description;

FIG. 20A is an exemplary circuit diagram of a first piezoelectric element shown in accordance with some embodiments of the present description;

FIG. 20B is another exemplary circuit diagram of a first piezoelectric element shown in accordance with some embodiments of the present description;

FIG. 21 is an exemplary block diagram of an acoustic output device shown in accordance with some embodiments of the present description;

FIG. 22 is a plot of the frequency response of an acoustic output device according to some embodiments of the present disclosure;

FIG. 23 is an exemplary block diagram of an acoustic output device shown in accordance with some embodiments of the present description;

fig. 24 is an exemplary block diagram of an acoustic output device according to some embodiments of the present description.

Detailed Description

In order to more clearly illustrate the technical solution of the embodiments of the present application, the drawings that are required to be used in the description of the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some examples or embodiments of the present application, and it is apparent to those of ordinary skill in the art that the present application may be applied to other similar situations according to the drawings without inventive effort. Unless otherwise apparent from the context of the language or otherwise specified, like reference numerals in the figures refer to like structures or operations.

It will be appreciated that "system," "apparatus," "unit" and/or "module" as used herein is one method for distinguishing between different components, elements, parts, portions or assemblies of different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

As used in the specification and in the claims, the terms "a," "an," "the," and/or "the" are not specific to a singular, but may include a plurality, unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that the steps and elements are explicitly identified, and they do not constitute an exclusive list, as other steps or elements may be included in a method or apparatus.

A flowchart is used in the present application to describe the operations performed by a system according to embodiments of the present application. It should be appreciated that the preceding or following operations are not necessarily performed in order precisely. Rather, the steps may be processed in reverse order or simultaneously. Also, other operations may be added to or removed from these processes.

The acoustic output device provided by the embodiments of the present specification may include, but is not limited to, bone conduction speakers, air conduction speakers, bone conduction hearing aids, air conduction hearing aids, or the like. The acoustic output device provided by the embodiments of the present specification may include a piezoelectric element. Piezoelectric elements may be used to convert electrical signals into mechanical vibrations. The piezoelectric element can convert an input voltage into mechanical vibration by an inverse piezoelectric effect to output a vibration displacement, and thus an acoustic output device that outputs a displacement through the piezoelectric element is also called a piezoelectric acoustic output device. The piezoelectric element in the piezoelectric acoustic output device generally has an operation mode of d33 and d 31. In the d33 operation mode, the polarization direction of the piezoelectric element is the same as the displacement output direction. In the d31 operation mode, the polarization direction of the piezoelectric element is perpendicular to the displacement output direction. Since piezoelectric elements generally have a relatively high resonant frequency, piezoelectric acoustic output devices are generally capable of enhancing high-frequency output, but piezoelectric elements have relatively poor low-frequency response, generally have a relatively large number of vibration modes in an audible range (e.g., 20Hz-20000 Hz), and are difficult to form relatively flat frequency response curves, thereby affecting sound quality output by the acoustic output devices.

In order to solve the problem that the piezoelectric acoustic output device has poor low-frequency response and more modes in the frequency range of the audible domain, the acoustic output device provided in the embodiments of the present disclosure may include a mass element and an elastic element, wherein a first resonance peak is constructed in the low-frequency range (for example, 20Hz-2000 Hz) by using a combined structure of the elastic element and the mass element, and a second resonance peak is constructed in the higher frequency range (for example, 1000Hz-20000 Hz) by using the piezoelectric element, so that a straight curve may be formed between the first resonance peak and the second resonance peak. Meanwhile, by arranging the shape and the structure of the elastic element, the elastic element can provide opposite rotation shear stress on a plane perpendicular to the vibration direction of the mass element, so that the rotation mode generated by the rotation of the mass element and/or the piezoelectric element in the plane is restrained, and the resonance valley generated by the rotation mode in the frequency response curve of the acoustic output device is improved.

Fig. 1 is an exemplary block diagram of an acoustic output device according to some embodiments of the present description. In some embodiments, acoustic output device 100 may include piezoelectric element 110, mass element 120, and elastic element 130. In some embodiments, the mass element 120 may be coupled to the piezoelectric element 110 by a resilient element 130. In some embodiments, the elastic element 130 may be one, and the mass element 120 may be connected to the piezoelectric element 110 through one elastic element 130. In some embodiments, the elastic element 130 may be plural, and the mass element 120 may be connected to the piezoelectric element 110 through one or more elastic elements 130. In some embodiments, the piezoelectric element 110 may be one or more. In some embodiments, the mass element 120 may be coupled to one piezoelectric element 110. In some embodiments, the mass element 120 may also be connected to a plurality of piezoelectric elements 110, respectively. In some embodiments, a plurality of piezoelectric elements 110 may be interconnected. In some embodiments, the plurality of piezoelectric elements 110 may be directly connected. In some embodiments, the plurality of piezoelectric elements 110 may also be connected by one or more elastic elements 130.

The piezoelectric element 110 may be a component having a piezoelectric effect. In some embodiments, the piezoelectric element 110 may be composed of a material having a piezoelectric effect, such as a piezoelectric ceramic, a piezoelectric polymer, or the like. In some embodiments, the piezoelectric element 110 may be used to convert an electrical signal into mechanical vibration. For example, when an alternating electrical signal is applied to the piezoelectric element 110, the piezoelectric element 110 may undergo a reciprocating deformation to generate mechanical vibration. In some embodiments, the vibration direction of the piezoelectric element 110 may be the same as the electrical direction (also referred to as the polarization direction) of the piezoelectric element 110. In some embodiments, the vibration direction of the piezoelectric element 110 and the electrical direction of the piezoelectric element 110 may also be perpendicular to each other.

In some embodiments, the number of piezoelectric elements 110 may be one or more. In some embodiments, when the number of the piezoelectric elements 110 is plural, the plural piezoelectric elements 110 may be connected by the elastic element 130. In some embodiments, any of the piezoelectric elements 110 interconnected by the elastic element 130 may be again connected to the mass element 120 by a further elastic element 130. In some embodiments, the piezoelectric elements 110 may be connected in series along the vibration direction of the piezoelectric elements 110, and the piezoelectric elements 110 connected in series may be connected to the mass element 120 through the elastic element 130.

In some embodiments, the piezoelectric element 110 may have a regular (e.g., circular, annular, rectangular, etc.) or irregular shape. For example, the piezoelectric element 110 may have a ring-shaped structure that is reciprocally deformed in the axial direction to generate mechanical vibration. For another example, the piezoelectric element 110 may include a piezoelectric sheet and a beam structure, where the piezoelectric sheet may be reciprocally deformed in a direction perpendicular to a polarization direction of the piezoelectric sheet, so as to drive the beam structure to warp along the polarization direction of the piezoelectric sheet to generate mechanical vibration. The direction of the mechanical vibration may be perpendicular to the long axis direction of the beam structure.

In some embodiments, the electrical direction (e.g., polarization direction) of the piezoelectric element 110 may be the same as the mechanical vibration direction of the piezoelectric element 110. For example, the piezoelectric element 110 may vibrate in a polarization direction of the piezoelectric element 110 under the action of an electrical signal. For example only, the piezoelectric element 110 may include an annular structure, which may be a columnar structure having an annular end face. In some embodiments, the polarization direction of the piezoelectric element 110 may be parallel to the axis direction of the ring structure, and the piezoelectric element 110 may vibrate along the axis direction of the ring structure of the piezoelectric element 110 under the action of the electrical signal. The axis of the annular structure may be a virtual line connecting the centroids of the two annular end faces of the columnar structure and the centroids of any cross-section parallel to the annular end faces. In some embodiments, the axial direction of the annular structure is perpendicular to the annular surface of the annular structure. In some embodiments, the shape of the annular end surface of the annular structure may include, but is not limited to, a circular ring, an elliptical ring, a curvilinear ring, a polygonal ring, or the like. In some embodiments, the polarization direction of the piezoelectric element 110 is parallel to the axis direction of the ring structure, and the piezoelectric element 110 may vibrate along the axis direction of the ring structure of the piezoelectric element 110 under the action of the electrical signal.

In some embodiments, the piezoelectric element 110 may include a piezoelectric sheet and a substrate. The substrate may be a beam structure, and the piezoelectric sheet is attached to the beam structure. Under the action of the electric signal, the piezoelectric sheet can be deformed in a reciprocating manner, so that the beam structure is driven to vibrate. By way of example only, the piezoelectric sheet may be reciprocally deformed in a direction perpendicular to the polarization direction of the piezoelectric sheet by an electrical signal. The reciprocating deformation can further drive the beam structure to warp along the polarization direction of the piezoelectric sheet, and mechanical vibration is generated. The vibration direction of the mechanical vibration is parallel to the electrical direction of the piezoelectric sheet.

The mass element 120 may be an element having a certain mass. In some embodiments, the mass element 120 may act as a vibrating plate or diaphragm of the acoustic output device 100 to cause the acoustic output device 100 to output vibrations through the mass element 120. In some embodiments, the material of the mass element 120 may be a metallic material or a non-metallic material. The metallic material may include, but is not limited to, steel (e.g., stainless steel, carbon steel, etc.), light-weight alloys (e.g., aluminum alloys, beryllium copper, magnesium alloys, titanium alloys, etc.), and the like, or any combination thereof. Nonmetallic materials may include, but are not limited to, polymeric materials, glass fibers, carbon fibers, graphite fibers, silicon carbide fibers, and the like. In some embodiments, the projection of the mass element 120 along the vibration direction of the mass element 120 may be regular and/or irregular polygons, such as circles, annuli, rectangles, pentagons, hexagons, and the like.

In some embodiments, the mass element 120 may be coupled to the piezoelectric element 110 by a resilient element 130, the mass element 120 receiving mechanical vibrations of the piezoelectric element 110 to generate an acoustic signal. In some embodiments, the resonance of the mass element 120 and the elastic element 130 coupled thereto may cause the acoustic output device 100 to generate a first resonance peak. The magnitude of the first resonant frequency corresponding to the first resonant peak is affected by the mass of the mass element 120 and the elastic coefficient of the elastic element 130. In some embodiments, the frequency of the first resonance peak (also referred to as the first resonance frequency) may be expressed by equation (1):

where f represents the first resonant frequency, m represents the mass of the mass element 120, and k represents the elastic coefficient of the elastic element 120. As can be seen from the formula (1), the magnitude of the first resonant frequency corresponding to the first resonant peak can be adjusted by adjusting the mass of the mass element 120 and/or the elastic coefficient of the elastic element 120, so that the first resonant peak is located within the desired frequency range.

In some embodiments, the mass element 120 may be coupled to the inner side of the piezoelectric element 110 by a resilient element 130. In some embodiments, when the piezoelectric element 110 generates vibration based on an electrical signal, the vibration is transmitted to the mass element 120 through the elastic element 130, causing the mass element 120 to generate vibration parallel to the vibration direction of the piezoelectric element 110. In some embodiments, the mass element 120 and the elastic element 130 may have one or more connection points. The projection of the connection point in the axial direction of the piezoelectric element 110 is located within the projection of the piezoelectric element 110 in the axial direction of the piezoelectric element 110.

In some embodiments, the mass element 120 may be coupled to the outside of the piezoelectric element 110 by a resilient element 130. For example, at least a portion of the mass element 120 is of an annular structure through which the mass element 120 may be connected to the piezoelectric element 110. For example, the annular structure may be located outside of the piezoelectric element 110, and the inner diameter of the annular structure may be larger than the outer diameter of the annular structure of the piezoelectric element 110, such that the projection of the annular structure of the mass element 120 along the axial direction of the piezoelectric element 110 may be located outside of the projection of the piezoelectric element 110 along the axial direction of the piezoelectric element 110.

In some embodiments, at least a portion of the mass element 120 may be located between the plurality of piezoelectric elements 110. In some embodiments, the piezoelectric element 110 may include a first piezoelectric element and a second piezoelectric element having different diameters, the second piezoelectric element being disposed inside the first piezoelectric element, and at least a portion of the mass element 120 may be located between the first piezoelectric element and the second piezoelectric element. In some embodiments, at least a portion of the mass element 120 may be an annular structure, and a projection of the annular structure of the mass element 120 along the axial direction of the piezoelectric element 110 may be located between projections of the first piezoelectric element and the second piezoelectric element along the axial direction of the piezoelectric element 110.

In some embodiments, when the mass element 120 is annular in shape, a side of the mass element 120 away from the piezoelectric element 110 in the axial direction of the piezoelectric element 110 may be provided with a cover plate. The cover plate may seal a side of the mass element 120 away from the piezoelectric element 110 in the axial direction of the piezoelectric element 110. For example, the mass element 120 may have a circular shape, and the cover plate may have a circular structure, and the circumferential side of the cover plate is connected to the side of the mass element 120 away from the piezoelectric element 110 in the axial direction of the piezoelectric element 110. By providing the cover plate on the side of the mass element 120 away from the piezoelectric element 110 in the axial direction of the piezoelectric element 110, the cover plate can be used as a vibration plate for transmitting vibration signals. In some embodiments, the cover plate may also be used to connect the mass element 120 with other structures of the acoustic output device 100, such as a diaphragm, in order to cause the acoustic output device 100 to drive the diaphragm to vibrate through the mass element 120.

The elastic member 130 may be a member capable of being elastically deformed by an external load. In some embodiments, the elastic element 130 may be a material having good elasticity (i.e., being subject to elastic deformation) such that the mass element 120 connected thereto has good vibration response capability. In some embodiments, the material of the elastic element 130 may include, but is not limited to, one or more of metal materials, polymer materials, glue materials, and the like. In some embodiments, the number of elastic elements 130 may be one or more. In some embodiments, the mass element 120 may be coupled to the piezoelectric element 110 by a resilient element 130. For example, the elastic member 130 may have a ring shape, and the mass member 120 and the piezoelectric member 110 may be connected through the ring-shaped elastic member 130. In some embodiments, the mass element 120 may be coupled to the piezoelectric element 110 by a plurality of elastic elements 130. For example, the elastic element 130 may include a rod structure, and a plurality of elastic elements 130 are distributed along the circumference of the piezoelectric element 110 and connected with the mass element 120.

In some embodiments, the elastic element 130 may be a vibration-transmitting sheet. When the elastic element 130 connects the mass element 120 and the piezoelectric element 110, the elastic element 130 may transmit the vibration generated by the piezoelectric element 110 to the mass element 120, so that the mass element 120 generates the vibration. In some embodiments, the elastic element 130 may also be a connecting rod disposed on the vibration-transmitting sheet, so that the processing of the acoustic output device 100 is easier and quicker.

In some embodiments, the elastic elements 130 may be a single layer structure, which means that one or more elastic elements 130 are located in the same plane perpendicular to the axial direction of the piezoelectric element 110. In some embodiments, the elastic element 130 may be a multi-layer structure, which means that a plurality of elastic elements are located in different planes perpendicular to the axial direction of the piezoelectric element 110.

In some embodiments, the shape of the resilient element 130 may include, but is not limited to, at least one of a dogleg shape, an S-shape, a spline-shape, an arc shape, and a straight shape. The shape of the elastic element 130 may be set according to the requirements of the acoustic output device 100 (e.g., the position of the first resonance peak, the ease of processing the acoustic output device 100, etc.).

In some embodiments, during vibration of the acoustic output device 100, since the elastic element 130 has a curved shape, the elastic element 130 may provide a shear stress to the mass element 120 (and/or the piezoelectric element 110) in a plane in which the curved shape lies, and when the shear stress rotations provided by the plurality of elastic elements 130 to the mass element 120 are the same, the mass element 120 (and/or the piezoelectric element 110) may have a tendency to rotate about its central axis. The shear stress may be a stress provided by the elastic element 130 to the mass element 120 (and/or the piezoelectric element 110) tangential to any cross-section of the mass element 120 perpendicular to the direction of vibration of the mass element 120. In some embodiments, at least two portions of the elastic element 130 (e.g., upper and lower ones of the elastic elements, the first and second bending regions 211, 212 in the rod structure 210, etc.) may provide rotationally opposite shear stresses in a plane perpendicular to the direction of vibration of the mass element 120. In some embodiments, where the elastic element 130 is coupled to the mass element 120 (and/or the piezoelectric element 110), at least two portions of the elastic element 130 may provide rotationally opposite shear stresses to the mass element 120 (and/or the piezoelectric element 110) in order to avoid a rotational tendency of the mass element 120 (and/or the piezoelectric element 110) coupled to the elastic element 130. The rotation (also referred to as a rotation vector) may be a vector operator for measuring the rotational properties of a vector field of shear stress, the magnitude of the vector operator may measure the degree of rotation of the vector field of shear stress, and the direction of the vector operator may measure the direction of rotation of the vector field of shear stress. The direction of the rotation vector can be determined according to the direction of rotation using the right hand rule. For example, when the piezoelectric element 110 rotates under the shear stress provided by the elastic element 130, the bending direction of the four fingers is consistent with the rotation (or rotation trend) direction of the ring structure according to the right-hand rule, and the direction of the thumb is the direction of the rotation vector. In some embodiments, the elastic element 130 may include at least two portions that may provide opposite rotations of the shear stress to the mass element 120 (and/or the piezoelectric element 110) so as to cancel each other out, such that the shear stress provided by the elastic element 130 as a whole to the mass element 120 is zero or near zero, thereby preventing or reducing rotation of the mass element 120.

In some embodiments, the elastic element 130 may include a plurality of rod structures, each rod structure including one or more bending regions (e.g., first bending region 211, second bending region 212, etc., as shown in fig. 2), each bending region providing a shear stress corresponding to one rotation. In some embodiments, the direction of rotation corresponding to the shear stress provided by each of the one or more inflection regions may be the same or different. In some embodiments, the direction of the corresponding rotation of the shear stress provided by each bending region may be opposite.

In some embodiments, when the number of the elastic elements 130 is plural, the rotation corresponding to the shear stress provided by the bending regions of the adjacent elastic elements 130 may be different. In some embodiments, when the elastic elements 130 are of a single-layer structure, the projections of the plurality of elastic elements 130 along the vibration direction of the mass element 120 may have two symmetry axes perpendicular to each other, so that the bending regions of adjacent elastic elements 130 provide different rotations corresponding to the shear stress.

In some embodiments, when the elastic element 130 is a multi-layer structure, the corresponding rotation of the shear stress provided by the bending regions of the elastic element 130 of different layers may be different. In some embodiments, the elastic element 130 may be a double-layer structure that may provide opposite rotation of shear stress. By way of example only, the elastic element 130 may include a first helical structure and a second helical structure that connect the mass element 120 and the piezoelectric element 110, respectively, in different planes perpendicular to the axial direction of the piezoelectric element 110. In some embodiments, the axes of the first and second helical structures may be the same and the helical directions are opposite. By providing the first spiral structure and the second spiral structure with opposite spiral directions, the rotation directions of the elastic elements 130 of different layers to the shear stress provided by the mass element 120 (and/or the piezoelectric element 110) can be opposite, so that the shear stress provided by the elastic elements 130 of different layers to the mass element 120 can be mutually offset, and further the rotation trend of the mass element 120 is avoided. For more description of the bending region of the elastic element 130 and its arrangement, reference may be made to fig. 2-8B and related description herein.

In some embodiments, the acoustic output device 100 may form at least two resonance peaks in the audible domain frequency range. In some embodiments, the elastic element 130 and the mass element 120 resonating may produce a first resonance peak; the piezoelectric element 110 resonates to produce a second resonance peak. In some embodiments, the frequency corresponding to the first resonance peak (which may also be referred to as a first resonance frequency) may be located in a low frequency range (e.g., less than 2000 Hz) and the frequency corresponding to the second resonance peak (which may also be referred to as a second resonance frequency) may be located in a medium-high frequency (e.g., greater than 1000 Hz) range. In some embodiments, the second resonant frequency corresponding to the second resonant peak may be higher than the first resonant frequency corresponding to the first resonant peak. In some embodiments, the second resonance peak and the first resonance peak do not exhibit a resonance valley therebetween, and a relatively flat curve may be formed between the first resonance peak and the second resonance peak, thereby improving the quality of the output sound of the acoustic output device 100.

In some embodiments, as can be seen from equation (1), the frequency range of the first resonant frequency corresponding to the first resonant peak can be adjusted by adjusting the mass of the mass element 120 and/or the elastic coefficient of the elastic element 130. In some embodiments, the first resonant peak may correspond to a first resonant frequency in the frequency range of 50Hz-2000 Hz. In some embodiments, to improve the sound output of the acoustic output device 100 in a lower frequency range, the frequency range of the first resonant frequency corresponding to the first resonant peak may be 50Hz-1000 Hz.

In some embodiments, the frequency range of the second resonant frequency corresponding to the second resonant peak may be adjusted by adjusting a structural parameter (e.g., size, shape, mass, material, etc.) of the piezoelectric element 110. In some embodiments, the second resonant frequency may be a natural frequency of the piezoelectric element 110. In some embodiments, the second resonant frequency corresponding to the second resonant peak may have a frequency range of 1000Hz-50000 Hz. In some embodiments, to improve the sound output of the acoustic output device 100 in a higher frequency range, the frequency range of the second resonance frequency corresponding to the second resonance peak may be 3000Hz-10000 Hz.

In some embodiments, in order to make the frequency response curve of the acoustic output device 100 have a flat area with a larger range between the first resonance peak and the second resonance peak, so as to ensure the low-frequency response of the acoustic output device 100 and the quality of the output sound, the frequency ratio of the second resonance frequency corresponding to the second resonance peak to the first resonance frequency corresponding to the first resonance peak may be in the range of 20-200. In some embodiments, the frequency ratio of the second resonant frequency corresponding to the second resonant peak to the first resonant frequency corresponding to the first resonant peak may range from 50 to 150.

In some embodiments, a resilient element may be used to connect the piezoelectric element with the mass element to transfer vibrations. The structural design of the elastic element can thus influence the vibration characteristics of the acoustic output device. In some embodiments, to meet the spring rate requirements of the spring element, the spring element may be curved to increase the length of the spring element and thereby decrease the spring rate of the spring element. In this arrangement, if the shape of the elastic element has a rotational or asymmetric configuration, the configuration may provide a shear stress to the mass element in a plane perpendicular to the vibration direction of the mass element, so that the mass element of the acoustic output device generates a rotation mode when vibrating, thereby affecting the output of the acoustic output device (which may be represented as a resonance valley in the frequency response curve), and thus affecting the vibration performance of the acoustic output device. Therefore, the structure of the elastic element can be reasonably designed to ensure the vibration performance of the acoustic output device.

In some embodiments, the elastic element may include a plurality of rod structures, and the mass element and the piezoelectric element are connected by the plurality of rod structures. The plurality of rod structures may be distributed along the circumference of the mass element. In some embodiments, the plurality of rod structures may be symmetrically distributed about the circumference of the mass element such that the symmetry of the elastic element (e.g., opposite rotations of the shear stress provided by the plurality of rod structures to the mass element) may be used to counter-phase the rotational mode in the event that the rotational mode may occur by the acoustic output device, thereby reducing or eliminating the resonant valleys created by the rotational mode.

In some embodiments, the shape of the bar structure may include at least one of a dogleg shape, an S-shape, a spline-shape, an arc shape, and a straight shape. In some embodiments, where the rod structure is of different shapes, the rod structure may have different bending regions that provide shear stress to the mass element (and/or piezoelectric element) that may correspond to different rotations. In some embodiments, the two ends of the rod structure are connected as the reference line, the rod structure may be alternately connected at two sides of the reference line to form sub-segments, and the segments formed by the same alternation rule of the sub-segments are the bending regions of the rod structure. Taking the shape of the elastic element as a fold line shape as an example, the fold line shape can be bent towards the first side of the reference line, then bent towards the second side of the reference line, and then bent towards the first side, so that the cycle is repeated, and when the cycle rule changes, the bending region of the fold line segment is ended.

Fig. 2 is an exemplary block diagram of a resilient element according to some embodiments of the present description. As shown in fig. 2, in some embodiments, the elastic element 200 may include a plurality of rod structures 210, each comprising one or more bending regions, each providing a shear stress corresponding to one rotation. For example, each rod structure 210 in the elastic element 200 in fig. 2 may include two bending regions, a first bending region 211 and a second bending region 212, respectively, where the first bending region 211 and the second bending region 212 are connected end to form the rod structure 210. In some embodiments, the first bending region may have a first bending direction and the second bending region may have a second bending direction. The bending direction may be a direction expressing the alternating regularity of the plurality of sub-segments on both sides of the reference line. As shown in fig. 2, the bending direction of the first bending region 211 may be a first direction, and the bending direction of the second bending region 212 may be a second direction, where the first direction and the second direction are opposite to each other with respect to a reference line (shown as a dashed line 201 in fig. 2) of the rod structure 210. In some embodiments, the first direction may be a counterclockwise direction with respect to a center of a projected shape of the elastic element in a projection plane along a vibration direction of the piezoelectric element, and the second direction may be a clockwise direction with respect to the center of the projected shape of the elastic element in the projection plane along the vibration direction of the piezoelectric element.

In some embodiments, the plurality of rod structures 210 of the resilient element 200 may lie in the same plane perpendicular to the direction of vibration of the mass element 203. It will also be appreciated that the plurality of bar structures 210 of the resilient element 200 lie in the same plane, which is perpendicular to the direction of vibration of the mass element 203.

In some embodiments, at least one of the plurality of rod structures 210 may include a plurality of segments that provide opposite shear stress rotations to the mass element 203. In some embodiments, when the rod structure 210 includes two segments, namely a first bending region 211 and a second bending region 212, the shear stress rotations provided by the first bending region 211 and the second bending region 212 to the mass element 203 may be reversed. For example, during the vibration of the elastic element 200, the first bending region 211 of the rod structure 210 causes the mass element 120 to have a tendency to rotate on a plane perpendicular to the vibration direction, which may be the first direction. At this time, the first bending region 211 may provide a shear stress in the first direction to the mass element 203 connected thereto. The shear stress provided by the first bending region 211 to the mass element 203 may have a first twist. Similarly, the second bending region 212 of the rod structure 210 also causes the mass element 120 to have a tendency to rotate in a plane perpendicular to the vibration direction, which may be the second direction, during vibration of the elastic element 200. At this time, the second bending region 212 may provide the first bending region 211 connected thereto with a shear stress in the second direction, so that the mass element 203 has a tendency to rotate in the second direction, which is equivalent to indirectly providing the mass element 203 with a shear stress in the second direction. For ease of description, in some embodiments, the shear stress provided by the elastic element or a portion thereof indirectly to the mass element may be referred to as the shear stress provided by the elastic element or a portion thereof to the mass element. Thus, the shear stress provided by the second bending region 212 to the mass element 203 may have a second twist.

In some embodiments, the rotation of the shear stress provided by the different bending regions in the rod structure 210 to the mass element 203 may be reversed. As shown in fig. 2, the bending directions of the first bending region 211 and the second bending region 212 are opposite, and during the vibration, the directions of the rotation trend of the first bending region 211 and the second bending region 212 on the plane perpendicular to the vibration direction are opposite, so that the tangential stress provided by the first bending region 211 to the mass element 203 is opposite to the tangential stress rotation provided by the second bending region 212 to the mass element 203. For example, the degree of rotation of the shear stress provided by the first bending region 211 to the mass element 203 is indicative of the plane of the paper, and the degree of rotation of the shear stress provided by the second bending region 212 to the mass element 203 is indicative of the plane of the paper.

In some embodiments, the first bending region 211 provides a first tangential stress of a first rotation to the mass element 203, the second bending region 212 provides a second tangential stress of a second rotation to the mass element 203, the first and second tangential stresses being opposite in direction, and the opposite effect between the first and second tangential stresses may enable the first and second modes of rotation of the mass element 203 due to rotation of the first bending region 211 to cancel each other, thereby reducing or eliminating resonance valleys generated by the modes of rotation.

In some embodiments, where the rod structure 210 includes a plurality of segments, for example, the rod structure 210 may include not only the first bending region 211 and the second bending region 212, but also further bending regions, for example, a third bending region, a fourth bending region, and so forth. Where the rod structure 210 comprises a plurality of segments, the rotation of the shear stress provided by adjacent ones of the plurality of segments to the mass element 203 may be reversed.

In some embodiments, at least one of the plurality of rod structures 210 may have at least one axis of symmetry in projection along the direction of vibration of the mass 203, the rod structures located on either side of the axis of symmetry providing opposite tangential stress rotations to the mass 203. For example, as shown in fig. 2, when the rod structure 210 includes a first bending region 211 and a second bending region 212, the projection of the rod structure 210 along the vibration direction of the mass element 203 may have an axis of symmetry 202. The symmetry axis 202 may be a straight line passing through the connection point a of the first bending region 211 and the second bending region 212 and perpendicular to the reference line 201 of the bar structure 210. The bar structures located on either side of the symmetry axis 202 provide opposite shear rotations to the mass element 203.

In some embodiments, the resilient element may comprise a plurality of lever structures. In some embodiments, when the plurality of rod structures are located in the same plane perpendicular to the vibration direction of the mass element, the plurality of rod structures may be arranged in a manner such that a projection of the plurality of rod structures after the arrangement along the vibration direction of the mass element may have at least two symmetry axes perpendicular to each other.

Fig. 3 is an exemplary block diagram of a resilient element according to some embodiments of the present description. In some embodiments, the number of the plurality of bar structures of the elastic element 300 may be even (e.g., 4, 8, etc.). As shown in fig. 3, in some embodiments, the number of rod structures connecting the mass element 320 and the piezoelectric element 330 may be 4, for example, the first rod structure 311, the second rod structure 312, the third rod structure 313, and the fourth rod structure 314. The 4 bar structures may be arranged to form an X-shape. In some embodiments, the rotation of shear stress provided by adjacent ones of the 4 rod structures to the mass element 320 may be opposite and the rotation of shear stress provided by opposing rod structures to the mass element 320 may be the same. For example, the first rod structure 311 and the second rod structure 312 provide opposite rotation of the shear stress to the mass element 320, and the third rod structure 313 and the fourth rod structure 314 provide opposite rotation of the shear stress to the mass element 320; the first rod structure 311 and the fourth rod structure 314 provide the same rotation of the shear stress to the mass element 320, and the second rod structure 312 and the third rod structure 313 provide the same rotation of the shear stress to the mass element 320. When the 4 rod structures are arranged in an X-shape, the projection of the 4 rod structures along the vibration direction of the mass element 320 may have two mutually perpendicular first symmetry axes 301 and second symmetry axes 302.

In some embodiments, in the elastic element 300, an angle may be formed between a single rod structure and an axis of symmetry (e.g., the first axis of symmetry 301 or the second axis of symmetry 302), for example, an angle θ may be formed between the fourth rod structure 314 and the first axis of symmetry 301. By adjusting and controlling the angle of the included angle theta, the rolling modes of the acoustic output device along different symmetry axes during vibration can be controlled. The rolling may refer to a rotation of the elastic element 300 about the first symmetry axis 301 or the second symmetry axis 302 upon vibration. In some embodiments, the included angle θ may range from 10 ° to 30 ° in order to minimize the rolling mode during vibration of the acoustic output device. In some embodiments, the included angle θ may range from 30 ° to 60 ° in order to minimize the rolling mode during vibration of the acoustic output device. In some embodiments, the included angle θ may range from 60 ° to 80 ° in order to minimize the rolling mode during vibration of the acoustic output device.

In some embodiments, the piezoelectric element 330 in the acoustic output device may be an annular structure (as shown in fig. 3), and the plurality of rod structures of the elastic element 300 are distributed along the circumferential direction of the annular structure. The mass element 320 and the piezoelectric element 330 are connected by a plurality of rod structures. It should be noted that, when the elastic elements are distributed in different shapes (for example, X-shaped distribution), the structure of the piezoelectric element 330 is not limited to the annular structure shown in fig. 3, and the piezoelectric element 330 may be of other structure types, for example, a beam structure (as shown in fig. 4). A specific description of the structure of the piezoelectric element 330 can be found in fig. 9 to 24 and the related description of the present specification.

Fig. 4 is an exemplary block diagram of a resilient element according to some embodiments of the present description. As shown in fig. 4, the acoustic output device 400 may further include a first elastic element 431 and a second elastic element 432. The second elastic element 432 and the first elastic element 431 are connected to the mass element 420, respectively. In some embodiments, the piezoelectric element 410 of the acoustic output device 400 may comprise a beam structure and the mass element 420 may be connected to a middle portion of the beam structure. For example, the mass element 420 may comprise a first mass element 421 and a second mass element 422, the second mass element 422 being connected to the middle of the beam structure. The second elastic element 432 and the first elastic element 431 are connected to the first mass element 421, respectively. In some embodiments, one or a set of opposing surfaces of the beam structure may have a piezoelectric patch (also referred to as a piezoelectric surface) attached thereto, which may deform in a telescoping manner based on the electrical signal, such that the beam structure may vibrate perpendicular to the piezoelectric surface based on the electrical signal. In some embodiments, the beam structure is provided with connectors 411 at both ends, and the beam structure is connected to one end of the bar structure of the first elastic element 431 (and the second elastic element 432) through the connectors 411 at both ends. The other end of the rod structure of the first elastic element 431 (and the second elastic element 432) is connected to the mass element 420.

In some embodiments, the second elastic element 432 and the first elastic element 431 may be located on the same plane, and the plane of the second elastic element 432 and the first elastic element 431 is perpendicular to the vibration direction of the mass element 420. In some embodiments, when the piezoelectric element 410 is a beam structure, the plane in which the second elastic element 432 and the first elastic element 431 lie may be parallel to the piezoelectric surface of the beam structure. In some embodiments, the piezoelectric element 410 may also be an annular structure, in which case the plane in which the second elastic element 432 and the first elastic element 431 lie may be parallel to the annular surface of the annular structure.

In some embodiments, the elastic element 430 may include 8 bar structures, and the 8 bar structures may form a double X shape. Wherein 4 rod structures in the first elastic element 431 may form a first X-shape 401, 4 rod structures in the second elastic element 432 form a second X-shape 402, and the first X-shape 401 and the second X-shape 402 form a double X-shape structure of a plurality of rod structures. In some embodiments, the double X-shaped structure of the plurality of rod structures may be parallel double X-shaped (as shown in FIG. 4), perpendicular double X-shaped (as shown in FIG. 5), or other forms of inversely symmetrically distributed shapes. Parallel/perpendicular double X-shapes may refer to two axes of symmetry of the first X-shape 401 and two axes of symmetry of the second X-shape 402 corresponding to parallel/perpendicular, respectively. In some embodiments, any of the double X-shaped structures shown in fig. 4 may be the same or similar to the X-shaped structure shown in fig. 3. For example, among the 4 rod structures in the first elastic element 431 and/or the second elastic element 432, the rotation of the shear stress provided by the adjacent rod structure to the mass element 420 may be opposite, and the rotation of the shear stress provided by the opposite rod structure to the mass element 420 may be the same.

In some embodiments, the central axis of the second elastic element 432 and the central axis of the first elastic element 431 may be disposed in parallel. The central axis of the first elastic element 431 (and/or the second elastic element 432) may be an axis that passes through the intersection of the extension lines of the straight lines where the 4 rod structures lie, and is perpendicular to the plane where the first elastic element 431 (and/or the second elastic element 432) lies. In some embodiments, the central axis of the first elastic element 431 (and/or the second elastic element 432) may be parallel to the direction of vibration of the mass element 420. In some embodiments, the dual X-shaped structure formed by the plurality of rod structures of the elastic element 430 may be made to be a parallel dual X-shaped structure by disposing the central axis of the second elastic element 432 parallel to the central axis of the first elastic element 431. In some embodiments, 4 rod structures in the first elastic element 431 forming the first X-shape 401 may be connected to one piezoelectric element 410 (e.g., beam structure) by a connection 411, and 4 rod structures in the second elastic element 432 forming the second X-shape 402 may be connected to the other piezoelectric element 410 (e.g., beam structure) by a connection 411, with the two piezoelectric elements 410 being disposed parallel to each other in the same plane. The 4 bar structures forming the first X-shape 401 and the 4 bar structures forming the second X-shape 402 are also connected to mass elements 420, respectively. In some embodiments, mass 420 may be one or more mass 420, and multiple mass 420 may be connected to each other by a rigid connection (not shown).

Fig. 5 is an exemplary block diagram of a resilient element according to some embodiments of the present description. As shown in fig. 5, in some embodiments, the second elastic element 432 and the first elastic element 431 may also be coaxially disposed. That is, the central axis of the second elastic member 432 coincides with the central axis of the first elastic member 431. In some embodiments, the projection of the double X-shaped structure formed by the plurality of rod structures of the elastic element 430 along the vibration direction may be double X-shapes perpendicular to each other. Two X-shapes being perpendicular to each other may refer to the symmetry axes of the two X-shapes being perpendicular to each other. In some embodiments, the second elastic member 432 and the first elastic member 431 may be located in the same plane perpendicular to the vibration direction. In some embodiments, the second elastic element 432 and the first elastic element 431 may lie in different planes perpendicular to the vibration direction. In some embodiments, any of the double X-shaped structures shown in fig. 5 may be the same or similar to the X-shaped structure shown in fig. 3. For example, among the 4 rod structures in the first elastic element 431 and/or the second elastic element 432, the rotation of the shear stress provided by the adjacent rod structure to the mass element 420 may be opposite, and the rotation of the shear stress provided by the opposite rod structure to the mass element 420 may be the same.

In some embodiments, the 4 rod structures forming the first X-shape 401 may be connected to one piezoelectric element (e.g., beam structure) by a connector 411, and the 4 rod structures forming the second X-shape 402 may be connected to another piezoelectric element, the two piezoelectric elements being disposed perpendicular to each other in the same plane.

In some embodiments, the vibration performance of the acoustic output device may vary when the shape and configuration of the elastic elements are different. The higher the degree of anti-symmetry of the elastic element, the fewer the rotational modes the elastic element vibrates to produce, and the higher the vibration performance of the acoustic output device. Fig. 6 is a plot of the frequency response of an acoustic output device according to some embodiments of the present description. As shown in fig. 6, the abscissa represents the resonance frequency of the acoustic output device in Hz, and the ordinate represents the acceleration output intensity of the acoustic output device in dB. Curve 601 may represent the frequency response curve of the acoustic output device when the elastic element is a single X-shape (e.g., elastic element 300 in fig. 3), curve 602 may represent the frequency response curve of the acoustic output device when the elastic element is a parallel double X-shape (e.g., elastic element 430 in fig. 4), and curve 603 may represent the frequency response curve of the acoustic output device when the elastic element is a non-parallel double X-shape (e.g., elastic element 430 in fig. 5). As can be seen from the combination of curve 601, curve 602 and curve 603, the frequency response of the acoustic output device is better when the elastic element is configured in a single X-shape, a parallel double X-shape and other types of double X-shapes. When the elastic element is in a single X shape, the curve 601 generates a resonance valley in the vicinity of 1411Hz, which is not generated by the rotation mode of the elastic element, but is caused by the vibration absorption of the output end by the mass element connected to the piezoelectric element and the vibration system formed by the piezoelectric element. For example, in connection with fig. 4, the resonance valley may be caused by the vibration system formed by the second mass element 422 and the piezoelectric beam 410 absorbing the vibrations of the first mass element 421.

In some embodiments, the elastic elements may also be provided in a double-layer structure, with the double-layer elastic elements being disposed up and down in the vibration direction of the mass element. In some embodiments, the rotation of the shear stress provided by the upper and lower elastic elements to the mass element may be reversed. For example, the rotation of the shear stress provided by the plurality of bending regions of the upper layer elastic element is opposite to the rotation of the shear stress provided by the plurality of bending regions of the lower layer elastic element. In some embodiments, the rotation of the shear stress provided by each of the two layers of elastic elements to the mass element may be reversed. For example, each layer of elastic elements may comprise at least two portions that may provide opposite rotational shear stresses to the mass element that may cancel each other out such that each layer of elastic elements provides zero or near zero shear stress to the mass element.

In some embodiments, the shape of the double-layered resilient element may be any of a double-layered dog bone shape, a double-layered S shape, a double-layered spline curve shape, a double-layered arc shape, or the like. For example, the first layer of the double-layer elastic element is a plurality of dogleg structures arranged along a first direction, and the second layer is a plurality of dogleg structures arranged along a second direction. The first direction and the second direction are opposite to the reference line direction of the rod member structure. For another example, each layer of the double layer resilient element may include a plurality of rod structures, and the projection of the plurality of rod structures of each layer along the vibration direction of the mass element may have two mutually perpendicular symmetry axes (e.g., double layer resilient element 300).

In some embodiments, when the structure of the elastic element is a double layer structure, each rod structure in the same layer of elastic element includes a plurality of bending regions, and the rotation of the shear stress provided by adjacent bending regions may be opposite. In some embodiments, the rotation of the shear stress provided by the two bar structures disposed opposite each other at different levels along the vibration direction of the mass element may also be reversed.

Fig. 7A is an exemplary block diagram of a resilient element according to some embodiments of the present description. Referring to fig. 7A, the elastic member 730 may include a first spiral structure 731 and a second spiral structure 732, and the first spiral structure 731 and the second spiral structure 732 connect the mass member 720 and the piezoelectric member 710, respectively. In some embodiments, the first and second helical structures 731, 732 may be arranged up and down along the direction of vibration of the mass element 720. The connection location of the first spiral structure 731 to the piezoelectric element 710 may be a side of the piezoelectric element 710 closer to the mass element 720. The connection location of the second spiral structure 732 and the piezoelectric element 710 may be a side of the piezoelectric element 710 that is farther from the mass element 720.

In some embodiments, the axes of the first helix 731 and the second helix 732 may be the same, and the helix directions are opposite. The helical direction may be the direction in which the helical structure rotates about its axis. In some embodiments, at least two of the elastic elements 730 may be rotated in opposite directions along the same axis to form first and second spiral structures 731 and 732 that are opposite in spiral direction.

In some embodiments, by providing the elastic member 730 in a double-layered helical structure, the amplitude of rotation of the elastic member 730 during vibration of the acoustic output device 700-1 may be reduced. Meanwhile, the double-layer spiral structure can also increase the elastic coefficient of the elastic element 730, so that the first resonance peak generated by the resonance of the elastic element 730 and the mass element 720 is shifted to the right (i.e. shifted to high frequency), so as to meet the requirement of the vibration performance of the acoustic output device 700-1.

Fig. 7B is an exemplary block diagram of a resilient element shown in accordance with some embodiments of the present description. The double helix structure of the elastic element 730 shown in fig. 7A may also be applied to the acoustic output device 700-2 shown in fig. 7B. The structure of the elastic element in fig. 7B is substantially the same as that of the elastic element in fig. 7A, except that the arrangement of the elastic elements is different.

Referring to fig. 7B, in some embodiments, the elastic member 760 may include a first spiral structure 761 and a second spiral structure 762, and the first spiral structure 761 and the second spiral structure 762 are arranged up and down in a thickness direction of the mass member 750. The spiral directions of the first spiral structure 761 and the second spiral structure 762 are opposite.

In some embodiments, the centers of first spiral structure 761 and second spiral structure 762 may be rigidly connected. First spiral 761 and second spiral 762 may be connected to mass 750 through a rigidly connected center. For example, the center of first spiral 761 and the center of second spiral 762 may be rigidly connected by a connector (not shown). The center of the rigid connection may be further connected to the mass element 750 by the connection. The first spiral structure 761 and the second spiral structure 762 may be connected to the piezoelectric element 710 through outer edges. In some embodiments, the outer edges of first spiral structure 761 and second spiral structure 762 may also be rigidly connected. For example, the outer edges of first spiral 761 and second spiral 762 may be rigidly connected by connection 711. The rigidly connected outer rim may further be connected to the piezoelectric element 710 by a connection 711.

In some embodiments, when the elastic element is a spiral structure, the number of layers of the spiral structure may be different, and the vibration performance of the corresponding acoustic output device may also be different. In some embodiments, the inverse symmetry of the double-layer helix is higher than the inverse symmetry of the single-layer helix, and thus the vibration performance of an acoustic output device in which the elastic element is a double-layer helix may be better than that of an acoustic output device in which the elastic element is a single-layer helix. Fig. 7C is an exemplary frequency response plot of an acoustic output device according to some embodiments of the present description. The curve 701 may represent the frequency response curve of the acoustic output device with the elastic element having a single-layer spiral structure, and the curve 702 may represent the frequency response curve of the acoustic output device with the elastic element having a double-layer spiral structure. Comparing the curve 701 and the curve 702, it can be seen that the peak value of the resonance valley formed by the frequency response curve 702 of the acoustic output device is significantly improved when the elastic element has a double-layer spiral structure compared to the elastic element having a single-layer spiral structure.

Fig. 8A is an exemplary block diagram of a resilient element according to some embodiments of the present description. Referring to fig. 8A, an acoustic output device 800-1 may include a piezoelectric element 810, a mass element 820, and a resilient element 830. Among them, the piezoelectric element 810 may include a first piezoelectric element 811 and a second piezoelectric element 812, the second piezoelectric element 812 being located inside the first piezoelectric element 811. The mass element 820 is located inside the second piezoelectric element 812.

In some embodiments, the elastic element 830 may include an inner ring elastic element 832 and an outer ring elastic element 831. In some embodiments, the rotation of the tangential stress provided by the inner ring elastic member 832 to the mass member 820 and the rotation of the tangential stress provided by the outer ring elastic member 831 to the mass member 820 may be opposite to each other, such that the elastic member 830 as a whole is capable of providing mutually offset tangential stresses to the mass member 820. In some embodiments, the shape of the inner ring elastic element 832 and the outer ring elastic element 831 may be S-shaped, with the S-shaped rod structure of the inner ring elastic element 832 providing a first rotation corresponding to a shear stress to the mass element 820 opposite to a second rotation corresponding to a shear stress provided by the S-shaped rod structure of the outer ring elastic element 831 to the mass element 820. The inner ring elastic member 832 may provide a shear stress of a first rotation to the mass member 820, and the outer ring elastic member 831 may provide a shear stress of a second rotation to the mass member 820, and since the first rotation is opposite to the second rotation, the elastic member 830 as a whole may provide a mutually offset shear stress to the mass member 820.

In some embodiments, when the rotation of the shear stress provided by the inner ring elastic member 832 to the mass member 820 is opposite to the rotation of the shear stress provided by the outer ring elastic member 831 to the mass member 820, the rotation modes of the inner ring elastic member 832 and the outer ring elastic member 831 may be opposite during vibration of the acoustic output device 800-1, such that the rotation modes of the inner ring elastic member 832 and the outer ring elastic member 831 cancel (or attenuate) each other, thereby reducing the rotation modes of the acoustic output device 800-1 during vibration as a whole.

Fig. 8B is an exemplary block diagram of a resilient element shown in accordance with some embodiments of the present description. The elastic element shown in fig. 8B is substantially the same as the elastic element shown in fig. 8A in terms of its shape. The elastic element 830 of the acoustic output device 800-2 is arcuate in shape. The first rotation of the shear stress provided by the arc of the inner ring elastic member 832 is opposite to the second rotation of the shear stress provided by the arc of the outer ring elastic member 831.

In some embodiments, where the elastic elements include inner ring elastic elements and outer ring elastic elements, the shape of the inner/outer ring elastic elements may not be limited to S-shapes and arcs, but may be other shapes, such as a polyline shape or spline curve shape, etc.

For more details on the elastic elements including the inner ring elastic element and the outer ring elastic element, reference can be made to fig. 12-18 and the related description herein.

Fig. 9 is an exemplary block diagram of an acoustic output device according to some embodiments of the present description. As shown in fig. 9, the acoustic output device 900 may include one or more piezoelectric elements 910, a mass element 920, and one or more elastic elements 930. Wherein at least one of the one or more elastic elements 930 may be used to connect the mass element 920 and the piezoelectric element 910.

In some embodiments, the one or more piezoelectric elements 910 may include a first piezoelectric element 911, and the first piezoelectric element 911 may be a ring structure. The axis direction of the annular structure is parallel to the vibration direction of the mass element 920. In some embodiments, one end of the first piezoelectric element 911 in the axial direction is fixed (also referred to as a fixed end), and the mass element 920 is connected to other positions on the first piezoelectric element 911 than this end through the elastic element 930. In the embodiment of the present specification, one end of a piezoelectric element (e.g., a first piezoelectric element, a second piezoelectric element, etc.) refers to an entire region having a certain thickness (e.g., any thickness in the range of 0.1%, 5%, or 0.1% to 30% of the total thickness of the ring structure) in the axial direction of the ring structure from one of the ring end faces of the ring structure of the piezoelectric element. For example, one end of the first piezoelectric element 911 in the axial direction may be fixed, and one of annular end faces of the first piezoelectric element 911 may be fixed. For another example, one end of the first piezoelectric element 911 in the axial direction may be fixed, and the inner surface and/or the outer surface of the annular structure may be fixed in the vicinity of one of the annular end surfaces of the first piezoelectric element 911 in a region having a certain thickness. In some embodiments, the resilient element 930 may be connected to another annular end face opposite the annular end face of the fixed end. In some embodiments, the elastic element 930 may also be attached to the inner side of the annular structure, and the attachment location of the inner side does not belong to the area of the fixed end.

In some embodiments, at least a portion of the mass element may be located inside the piezoelectric element. For example, the projection of the connection point of the mass element and the elastic element in the axial direction of the piezoelectric element is located within the projection of the piezoelectric element in the axial direction. For example, as shown in fig. 9, projections of the piezoelectric element 910, the elastic element 930, and the mass element 920 in the axial direction of the piezoelectric element 910 are arranged in order from the outside to the inside. In some embodiments, when the mass element 920 may be located inside the first piezoelectric element 911, the mass element 920 may have a shape of a column (as shown in fig. 9), a ring, or the like.

In some embodiments, the elastic element 930 connecting the mass element 920 and the first piezoelectric element 911 may include a plurality of rod structures distributed along the circumferential direction of the ring structure. In some embodiments, one end of the elastic element 930 may be connected to either surface of the mass element 920 in the axial direction (e.g., the surface near the piezoelectric element 910). In other embodiments, one end of the elastic element 930 may also be connected to the circumferential surface of the mass element 920. In some embodiments, the other end of the elastic element 930 may be attached to either surface of the piezoelectric element 910 that is not fixed. For example, in some embodiments, the other end of the resilient element 930 may be coupled to the annular end surface of the piezoelectric element 910 proximate to the mass element 920. For another example, in some embodiments, the other end of the elastic element 930 may also be connected to the circumferential inner surface of the piezoelectric element 910. The connection location of the elastic element 930 to the mass element 920 and/or the piezoelectric element 910 may be set according to the structural feasibility of the acoustic output device 900.

In some embodiments, the resilient element 930 may include at least two portions that may provide opposite rotational shear stresses to the mass element 920 that may cancel each other such that the resilient element 930 provides zero or near zero shear stress to the mass element 920. For example, each of the plurality of rod structures may include one or more inflection regions, and the shear stress rotations provided by adjacent ones of the one or more inflection regions to the mass element 920 may be reversed such that the shear stress provided by each rod structure as a whole to the mass element 920 is zero or near zero. In some embodiments, the structure of the elastic element 930 may be the same as or similar to the structure of the elastic element described in fig. 2-5, and reference may be made to fig. 2-5 and the associated description for details of the structure of the elastic element.

In some embodiments, the mass element 920 and the elastic element 930 resonate to produce a first resonant peak and the first piezoelectric element 911 resonates to produce a second resonant peak. The position of the first resonance peak, that is, the magnitude of the first resonance frequency corresponding to the first resonance peak, may be determined by the mass of the mass element 920 and the elastic coefficient of the elastic element 930. The location of the second resonance peak, i.e., the magnitude of the second resonance frequency corresponding to the second resonance peak, may be determined by a structural parameter (e.g., a dimension) of the piezoelectric element 910.

Fig. 10 is a plot of the frequency response of an acoustic output device according to some embodiments of the present description. As shown in fig. 10, the abscissa represents the resonance frequency of the acoustic output device in Hz, and the ordinate represents the acceleration output intensity of the acoustic output device in dB. In some embodiments, referring to fig. 10, an acoustic output device (e.g., acoustic output device 900) may form at least two resonant peaks in the audible range (e.g., 20Hz-20 KHz) frequency range, wherein a first resonant peak 1010 may be generated by the resonance of mass element 920 and elastic element 930 and a second resonant peak 1020 may be generated by the resonance of piezoelectric element 910. In some embodiments, the frequency f1 of the first resonant peak 1010 of the acoustic output device 900 can be in the range of 50Hz-9000Hz. In some embodiments, to ensure a low frequency response of the acoustic output device 900, the frequency f1 of the first resonance peak 1010 of the acoustic output device 900 may be in the range of 50Hz-500Hz. In some embodiments, to ensure a low frequency response of the acoustic output device 900, the frequency f1 of the first resonance peak 1010 of the acoustic output device 900 may be in the range of 50Hz-300Hz. In some embodiments, the frequency f2 of the second resonant peak 1020 of the acoustic output device 900 may be in the range of 1000Hz-90000Hz. In some embodiments, to ensure a high frequency response of the acoustic output device 900, the frequency f2 of the second resonant peak 1020 of the acoustic output device 900 may be in the range 9000Hz-10000Hz. In some embodiments, to ensure the quality of sound output by the acoustic output device 900 in the frequency response range, the frequency f2 of the second resonant peak 1020 of the acoustic output device 900 may be in the range of 3000Hz-7000Hz. The frequency response curve between the first resonance peak 1010 and the second resonance peak 1020 may be relatively flat, and the acoustic output device 900 has a relatively high output response capability in a frequency range between the first resonance frequency f1 and the second resonance frequency f2, and may output sound with relatively high sound quality when the acoustic output device 900 is applied to the acoustic output device.

In some embodiments, at least a portion of the mass element may be located outside of the piezoelectric element. For example, at least a portion of the mass element may be of annular configuration, the annular configuration of the mass element being connected to the piezoelectric element by an elastic element. The projection of the annular structure of the mass element along the axis of the annular structure may be located outside the projection of the piezoelectric element along said axis. Fig. 11A is an exemplary block diagram of an acoustic output device according to some embodiments of the present description. As shown in fig. 11A, the mass element 1120 may be located outside the first piezoelectric element 1111, and a projection of the mass element 1120 in the axial direction of the first piezoelectric element 1111 is located outside a projection of the first piezoelectric element 1111 in the axial direction, and the mass element 1120 and the first piezoelectric element 1111 are connected by an elastic element 1130. The projections of the first piezoelectric element 1111, the elastic element 1130, and the mass element 1120 in the axial direction of the first piezoelectric element 1111 are sequentially arranged from inside to outside. In some embodiments, the mass element 1120 may be annular in shape when the mass element 1120 is located outside of the first piezoelectric element 1111.

In some embodiments, when the mass element 1120 is located outside the first piezoelectric element 1111, a side of the mass element 1120 away from the first piezoelectric element 1111 in the axial direction of the first piezoelectric element 1111 may be provided with a cover plate 1121. The cover plate 1121 may seal a side of the mass element 1120 away from the first piezoelectric element 1111 in the axial direction of the first piezoelectric element 1111. For example, the cover plate 1121 may have a circular structure, and the circumferential side of the cover plate 1121 and the side of the mass element 1120 away from the first piezoelectric element 1111 in the axial direction of the first piezoelectric element 1111 are disposed in alignment and closely connected. By providing the cover 1121 on the side of the mass element 1120 away from the first piezoelectric element 1111 in the axial direction of the first piezoelectric element 1111, the cover 1121 can be used as a vibration plate for transmitting vibration signals. The cover 1121 may also be used to connect the mass element 1120 to other structures of the acoustic output device 1100, such as a diaphragm.

Fig. 11B is a plot of the frequency response of an acoustic output device according to some embodiments of the present description. When the mass element 1120 is located outside the first piezoelectric element 1111, a frequency response graph of the acoustic output device 1100 may be as shown in fig. 11B. In some embodiments, the frequency f1 of the first resonance peak 1101 of the acoustic output device 1100 (also referred to as the first resonance frequency) may be in the range of 50Hz-11000Hz. In some embodiments, to ensure a low frequency response of the acoustic output device 1100, the frequency f1 of the first resonant peak 1101 of the acoustic output device 1100 may be in the range of 50Hz-500Hz. In some embodiments, to ensure a low frequency response of the acoustic output device 1100, the frequency f1 of the first resonant peak 1101 of the acoustic output device 1100 may be in the range of 50Hz-300Hz. In some embodiments, the frequency f2 (also referred to as the second resonant frequency) of the second resonant peak 1102 of the acoustic output device 1100 can be in the range of 1000Hz-50000Hz.

In some embodiments, to ensure a high frequency response of the acoustic output device 1100, the frequency f2 of the second resonance peak 1102 of the acoustic output device 1100 may be in the range of 1000Hz-10000Hz. In some embodiments, to ensure a high frequency response of the acoustic output device 1100, the frequency f2 of the second resonant peak 1102 of the acoustic output device 1100 may be in the range of 4000Hz-8000Hz.

Fig. 12 is an exemplary block diagram of an acoustic output device according to some embodiments of the present description. Referring to fig. 12, the acoustic output device 1200 can include one or more piezoelectric elements 1210, a mass element 1220, and one or more elastic elements 1230. Wherein at least one of the one or more elastic elements 1230 may be used to connect the mass element 1220 and the piezoelectric element 1210.

In some embodiments, the one or more piezoelectric elements 1210 may include a first piezoelectric element 1211 and a second piezoelectric element 1212, the first piezoelectric element 1211 including a first annular structure and the second piezoelectric element 1212 including a second annular structure; the second piezoelectric element 1212 is disposed inside the first ring structure. In some embodiments, one end of the first piezoelectric element 1211 in the axial direction (e.g., the end remote from the mass element 1220) may be fixed, and the second piezoelectric element 1212 is connected to a location other than the fixed end of the first piezoelectric element 1211 through at least one of the one or more elastic elements 1230; the mass element 1220 is connected to the second piezoelectric element 1212 through at least another one of the one or more elastic elements 1230. In some embodiments, at least a portion of the mass element 1220 may be located inside the second piezoelectric element 1212. For example, the projection of the connection point of the mass element 1220 and the elastic element 1230 (e.g., the inner ring elastic element 1232) along the axial direction may be located within the projection of the second annular structure along the axial direction.

In some embodiments, the elastic elements 1230 may include an outer ring elastic element 1231 and an inner ring elastic element 1232. The outer ring elastic member 1231 is located between the first piezoelectric element 1211 and the second piezoelectric element 1212, and the first piezoelectric element 1211 and the second piezoelectric element 1212 are connected by the outer ring elastic member 1231. The inner ring elastic member 1232 is located between the second piezoelectric element 1212 and the mass element 1220, and the second piezoelectric element 1212 and the mass element 1220 are connected by the inner ring elastic member 1232.

In some embodiments, the inner and outer ring elastic elements 1232, 1231 provide opposite shear stress rotations to the mass element 1220. In some embodiments, the plurality of rod structures in the inner ring elastic element 1232 and the plurality of rod structures of the outer ring elastic element 1231 may respectively provide opposite shear stress rotations to the mass element 1220. For example, the inner ring elastic member 1232 may provide a shear stress of a first rotation to the mass member 1220 and the outer ring elastic member 1231 may provide a shear stress of a second rotation to the mass member 1220. In some embodiments, as shown in fig. 12, the inner ring elastic element 1232 and the outer ring elastic element 1231 may comprise a plurality of rod structures, each rod structure comprising one or more bending regions. By providing opposite bending directions of the rod structures in the inner and outer ring elastic members 1232, 1231, the first rotation can be made opposite to the second rotation, thereby achieving that the inner and outer ring elastic members 1232, 1231 provide opposite rotation shear stresses to the mass member 1220. In some embodiments, the shape of the inner ring elastic member 1232 and the outer ring elastic member 1231 may not be limited to the S shape as shown in fig. 12, but may be other shapes, such as a zigzag shape, a spline shape, an arc shape, a straight shape, and the like. In some embodiments, the inner ring elastic element 1232 and the outer ring elastic element 1231 may further comprise a helical structure. By providing the helical structures in the inner and outer annular elastic elements 1232, 1231 with opposite helical directions, the first and second convolutions can be reversed, thereby achieving that the inner and outer annular elastic elements 1232, 1231 provide opposite-convolutions of shear stress to the mass element 1220. Thus, the shear stresses provided by the inner and outer ring elastic members 1232, 1231 to the mass member 1220 may cancel each other, bringing the shear stresses provided by the elastic members 1230 to the mass member 1220 to zero or near zero, thereby preventing or reducing rotation of the mass member 1220.

In some embodiments, by providing the second piezoelectric element 1212 and the mass element 1220 (and the elastic element connecting the second piezoelectric element 1212 and the mass element 1220) in the acoustic output device 1200, the first resonance peak of the acoustic output device 1200 is shifted to a low frequency due to the fact that the integral mass is larger than the mass of the mass element when the integral mass resonates with the elastic element connecting the integral mass and the first piezoelectric element 1211, and the double-loop structure resonance of the first loop structure and the second loop structure when the acoustic output device 1200 vibrates can also generate a third resonance peak located between the first resonance peak and the second resonance peak, which can be expressed as an additional resonance peak, i.e., a third resonance peak, in the frequency response curve of the acoustic output device 1200 at a position between the first resonance peak and the second resonance peak. In some embodiments, the third resonant frequency corresponding to the third resonant peak may be located between the first resonant frequency corresponding to the first resonant peak and the second resonant frequency corresponding to the second resonant peak. In some embodiments, the frequency range of the first resonance peak of the acoustic output device 1200 having the double loop structure may be 50Hz-2000Hz. In some embodiments, to ensure a low frequency response of the acoustic output device 1200, the frequency range of the first resonant peak of the acoustic output device 1200 having a double loop structure may be 50Hz-1000 Hz. In some embodiments, to ensure a low frequency response of the acoustic output device 1200, the frequency range of the first resonance peak of the acoustic output device 1200 having a double loop structure may be 50Hz-500Hz. In some embodiments, to ensure a low frequency response of the acoustic output device 1200, the frequency range of the first resonant peak of the acoustic output device 1200 having a double loop structure may be 50Hz-100Hz.

Fig. 13 is a plot of the frequency response of an acoustic output device according to some embodiments of the present description. Wherein curve 1310 may represent a frequency response curve of an acoustic output device (e.g., acoustic output device 900) in which only a first piezoelectric element is disposed, curves 1320, 1330, 1340, and 1350 represent frequency response curves of acoustic output devices (e.g., acoustic output device 1200) in which the first piezoelectric element and the second piezoelectric element are disposed, and electrical signals received by the first piezoelectric element and the second piezoelectric element have different phase differences. Comparing the curve 1310 with the curves 1320-1350, it can be seen that when the second piezoelectric element is additionally disposed on the acoustic output device, not only the first resonant peak 1301 and the second resonant peak 1302, but also one resonant peak, i.e. the third resonant peak 1303, can be additionally formed in the frequency response curve 1320 of the acoustic output device.

In some embodiments, when the acoustic output device includes a first piezoelectric element and a second piezoelectric element, at least a portion of the mass element may be located outside of the first piezoelectric element. Fig. 14 is an exemplary block diagram of an acoustic output device according to some embodiments of the present description. As shown in fig. 14, one or more piezoelectric elements 1410 may include a first piezoelectric element 1411 and a second piezoelectric element 1412, the first piezoelectric element 1411 including a first annular structure, the second piezoelectric element 1412 including a second annular structure; the second piezoelectric element 1412 is disposed inside the first annular structure. In some embodiments, one end of the second piezoelectric element 1412 in the axial direction of the ring structure may be fixed, and the first piezoelectric element 1411 is connected to other positions than the fixed end of the second piezoelectric element 1412 by at least one of the one or more elastic elements 1430 (e.g., the inner ring elastic element 1432); at least a portion of the mass element 1420 may be an annular structure, the annular structure of the mass element 1420 being connected to the first annular structure by an outer annular elastic element 1431 in the elastic element 1430, the projection of the annular structure of the mass element 1420 in the axial direction may be located outside the projection of the first annular structure in the axial direction. In some embodiments, as shown in fig. 14, the inner ring elastic element 1432 and the outer ring elastic element 1431 may comprise a plurality of lever structures, each lever structure comprising one or more bending regions. In some embodiments, the shape of the inner ring elastic element 1432 and the outer ring elastic element 1431 may not be limited to S-shape as shown in fig. 14, but may be other shapes, for example, a zigzag shape, a spline shape, an arc shape, a straight shape, and the like. In some embodiments, the inner ring elastic element 1432 and the outer ring elastic element 1431 may further comprise a helical structure. In some embodiments, the inner ring elastic element 1432 may provide a shear stress of a first rotation to the mass element 1420 and the outer ring elastic element 1431 may provide a shear stress of a second rotation to the mass element 1420. By providing the structures of the inner ring elastic element 1432 and the outer ring elastic element 1431 (e.g., opposite bending directions of the rod structure, opposite spiral directions of the spiral structure, etc.), the first rotation can be made opposite to the second rotation, thereby achieving that the inner ring elastic element 1432 and the outer ring elastic element 1431 provide opposite rotation shear stresses to the mass element 1420. Enabling the elastic element 1430 to provide zero or near zero shear stress to the mass element 1420, thereby preventing or reducing rotation of the mass element 1420.

In some embodiments, the acoustic output device 1400 includes a first piezoelectric element 1411 and a second piezoelectric element 1412, and when the mass element 1420 is located outside the first piezoelectric element 1411, a side of the mass element 1420 away from the first piezoelectric element 1411 in the axial direction of the first piezoelectric element 1411 may be provided with a cover plate. In some embodiments, the closed side of the mass element 1420 (i.e. the side of the mass element 1420 where the cover plate is located) may extend away from the unsealed side, and the projection of the closed surface of the mass element 1420 in the axial direction may be of various shapes, e.g. circular, square, etc. The unsealed end of the mass element 1420 is connected to the piezoelectric element 1410 (e.g., the first piezoelectric element 1411), and the end face of the unsealed end of the mass element 1420 is annular in projection in the axial direction.

In some embodiments, the first piezoelectric element 1411 and the mass element 1420 (and the elastic element connecting the first piezoelectric element 1411 and the mass element 1420) may form a unitary mass that when resonated with the elastic element connecting the unitary mass and the second piezoelectric element 1412 may cause the first resonant peak of the acoustic output device 1400 to move toward a low frequency and the dual ring structure resonance of the acoustic output device 1400 may also generate a third resonant peak between the first resonant peak and the second resonant peak.

Fig. 15 is a plot of the frequency response of an acoustic output device according to some embodiments of the present description. Wherein curve 1510 may represent a frequency response curve of an acoustic output device (e.g., acoustic output device 900) in which only a first piezoelectric element is disposed, curves 1520, 1530, 1540, and 1550 represent frequency response curves of an acoustic output device (e.g., acoustic output device 1400) in which the first piezoelectric element and a second piezoelectric element are disposed, and electrical signals received by the first piezoelectric element and the second piezoelectric element have different phase differences. Comparing the curve 1510 and the curves 1520-1550, it can be seen that when the acoustic output device is additionally provided with the second piezoelectric element, not only the first resonant peak 1501, the second resonant peak 1502, but also the third resonant peak 1503 can be formed in the frequency response curve 1520 of the acoustic output device.

In some embodiments, when the acoustic output device includes a first piezoelectric element and a second piezoelectric element, at least a portion of the mass element may be located between the first piezoelectric element and the second piezoelectric element. Fig. 16 is an exemplary block diagram of an acoustic output device according to some embodiments of the present description. As shown in fig. 16, in some embodiments, at least a portion of mass element 1620 may be an annular structure, with the annular structure of mass element 1620 being located between the first annular structure of first piezoelectric element 1611 and the second annular structure of second piezoelectric element 1612. The projection of the annular structure of mass element 1620 in the axial direction may be located between the projections of the first annular structure and the second annular structure in the axial direction. The annular structure of mass element 1620 is coupled to first piezoelectric element 1611 by at least one of the one or more elastic elements 1630 (e.g., outer annular elastic element 1631) and mass element 1620 is coupled to second piezoelectric element 1612 by at least another of the one or more elastic elements (e.g., inner annular elastic element 1632). In some embodiments, the shape of the elastic elements 1630 (e.g., the outer ring elastic element 1631 and/or the inner ring elastic element 1632) may be S-shaped, and the bending directions of adjacent S-shaped elastic elements 1630 may be opposite, such that adjacent S-shaped elastic elements 1630 may provide rotationally opposite shear stresses to the mass element 1620, thereby avoiding a rotational tendency of the mass element 1620 to rotate about an axis, and thus avoiding a rotational mode of the acoustic output device 1600. In some embodiments, the projection of the elastic element 1630 along the vibration direction (i.e., the axial direction) of the mass element 1620 may have at least one symmetry axis (e.g., the first symmetry axis 1601 and/or the second symmetry axis 1601 shown in fig. 16) such that the corresponding rotation degrees of the shear stresses provided along the S-shapes of symmetry axes are different (e.g., opposite), such that the S-shaped elastic elements 1630 on both sides of the symmetry axis may provide opposite rotation degrees of the shear stresses to the mass element 1620, thereby avoiding a rotational tendency of the mass element 1620 to rotate about the axial direction and thus avoiding a rotational mode of the acoustic output device 1600. In some embodiments, referring to fig. 16, the connection locations of adjacent S-shaped elastic elements 1630 on mass element 1620 or piezoelectric element 1610 (e.g., first piezoelectric element 1611 and/or second piezoelectric element 1612) may be the same. In other embodiments, the attachment locations of adjacent S-shaped elastic elements 1630 to mass element 1620 or piezoelectric element 1610 (e.g., first piezoelectric element 1611 and/or second piezoelectric element 1612) may also be different. In some embodiments, the shape of the inner and outer ring elastic elements 1632, 1631 may not be limited to the S-shape shown in fig. 16, but may be other shapes, such as, for example, dog bone, spline, arc, straight, etc. In some embodiments, the inner and outer ring elastic elements 1632, 1631 may also include a helical structure. By providing the inner and outer ring elastic elements 1632, 1631 with structures (e.g., opposite bending directions of the rod structures, opposite helical directions of the helical structures, etc.), the inner and outer ring elastic elements 1632, 1631 may be caused to provide rotationally opposite shear stresses to the mass element 1620. Thereby enabling the spring element 1630 to provide zero or near zero shear stress to the mass element 1620, thereby preventing or reducing rotation of the mass element 1620.

In some embodiments, the first piezoelectric element 1611 or the second piezoelectric element 1612 may have a fixed end in the axial direction. In some embodiments, the first piezoelectric element 1611 is fixed at one end in the axial direction, the second piezoelectric element 1612 is freely disposed at two end surfaces in the axial direction, the second piezoelectric element 1612 may be a piezoelectric free ring, and the first piezoelectric element 1611 may be a piezoelectric fixed ring. Or when one end of the second piezoelectric element 1612 in the axial direction is fixed, the two end surfaces of the first piezoelectric element 1611 in the axial direction are freely disposed, the first piezoelectric element 1611 may be a piezoelectric free ring, and the second piezoelectric element 1612 may be a piezoelectric fixed ring. In some embodiments, where different ones of the at least one piezoelectric elements 1610 have fixed ends in the axial direction, the acoustic output device 1600 may have different frequency response curves. The integral mass of the piezoelectric free ring and the mass element 1620 (and the elastic element connecting the piezoelectric free ring and the mass element 1620) may resonate with the elastic element connecting this integral mass and the piezoelectric fixed ring, allowing the first resonant peak to move to a lower frequency, and the piezoelectric free ring and the piezoelectric fixed ring are indirectly connected (i.e., connected through the outer ring elastic element 1631, the mass element 1620 and the inner ring elastic element 1632), such that the piezoelectric free ring and the piezoelectric fixed ring resonate to form a third resonant peak in the frequency response curve when the acoustic output device 1600 vibrates. The third resonance frequency corresponding to the third resonance peak may be located between the first resonance frequency corresponding to the first resonance peak and the second resonance frequency corresponding to the second resonance peak. In some embodiments, the frequency range of the first resonance peak of the acoustic output device 1600 may be similar to the frequency range of the first resonance peak of the acoustic output device 1200, and will not be described here.

Fig. 17 is a plot of the frequency response of an acoustic output device according to some embodiments of the present description. The frequency response curves other than the curve 1710 in fig. 17 may be the frequency response curves of an acoustic output device (e.g., the acoustic output device 1600) in which the first piezoelectric element (e.g., the first piezoelectric element 1611) has a fixed end in the axial direction. Referring to fig. 17, a curve 1710 may represent a frequency response curve of an acoustic output device (e.g., acoustic output device 900) in which only a first piezoelectric element is disposed, and curves 1720, 1730, and 1740 represent frequency response curves of acoustic output devices in which the first piezoelectric element and a second piezoelectric element are disposed, and electrical signals received by the first piezoelectric element and the second piezoelectric element have different phase differences. As can be seen from comparing curve 1710 and curves 1720-1740, when the acoustic output device is provided with a first piezoelectric element and a second piezoelectric element, a third resonance peak 1703 other than the first resonance peak 1701 and the second resonance peak 1702 may also be formed in the frequency response curve 1720 of the acoustic output device.

Fig. 18 is a plot of the frequency response of an acoustic output device according to some embodiments of the present description. The frequency response curve in fig. 18 may be a frequency response curve of an acoustic output device in which a second piezoelectric element (e.g., second piezoelectric element 1612) has a fixed end in the axial direction, in addition to curve 1810. Wherein curve 1810 may represent a frequency response curve of an acoustic output device (e.g., vibration device 900) in which only a first piezoelectric element is disposed, curves 1820, 1830, and 1840 represent frequency response curves of acoustic output devices (e.g., acoustic output device 1600) in which the first piezoelectric element and a second piezoelectric element are disposed, and electrical signals received by the first piezoelectric element and the second piezoelectric element have different phase differences. As can be seen from comparing curves 1810 and curves 1820-1840, when the acoustic output device is provided with the first piezoelectric element and the second piezoelectric element, a third resonance peak 1803 other than the first resonance peak 1801 and the second resonance peak 1802 may also be formed in the frequency response curve 1820 of the acoustic output device.

Fig. 19 is an exemplary block diagram of an acoustic output device according to some embodiments of the present description. Referring to fig. 19, an acoustic output device 1900 may include one or more piezoelectric elements 1910, a mass element 1920, and one or more elastic elements 1930. In some embodiments, one or more of the piezoelectric elements 1910 may include two first piezoelectric elements 1911, and the two first piezoelectric elements 1911 may be distributed up and down along the axis direction and connected to each other. The two first piezoelectric elements 1911 are distributed up and down along the axis direction to form a double-layer single-ring structure of the piezoelectric elements 1910.

In some embodiments, the mass element 1920 may be coupled to the two first piezoelectric elements 1911 by one or more elastic elements 1930, respectively. In some embodiments, one or more resilient elements 1930 may be provided in two layers, the two layers of resilient elements 1930 including two layers of first resilient elements 1931, the two layers of first resilient elements 1931 being arranged up and down along the axis of the piezoelectric element 1910. In some embodiments, two layers of first resilient elements 1931 may be respectively connected to the circumferences of the two first piezoelectric elements 1911. The mass element 1920 is connected to the two piezoelectric elements 1911 by two layers of first elastic elements 1931, respectively. In some embodiments, the two layers of first resilient elements 1931 may provide opposite rotational shear stresses to the mass elements 1920. In some embodiments, the two-layer first resilient element 1931 may each include a plurality of rod structures, and the direction of bending of the plurality of rod structures of the first layer and the direction of bending of the plurality of rod structures of the second layer may be reversed such that a first rotation of the first layer resilient element providing a tangential stress to the mass element 1920 is opposite to a second rotation of the second layer resilient element providing a tangential stress to the mass element 1920, such that the two-layer first resilient element 1931 provides a tangential stress to the mass element 1920 that is zero or near zero, thereby preventing or reducing rotation of the mass element 1920. In some embodiments, the two layers of first resilient elements 1931 may also include a first helical structure and a second helical structure, the first helical structure being the same axis as the second helical structure and having opposite helical directions, such that the first helical structure and the second helical structure may provide rotationally opposite shear stresses to the mass elements 1920.

In some embodiments, when the number of the first piezoelectric elements 1911 is two, the displacement changes of the two first piezoelectric elements 1911 in the axial direction during vibration may be opposite. That is, one of the two first piezoelectric elements 1911 is displaced in the axial direction during vibration to become larger (i.e., elongated), and the other of the two first piezoelectric elements 1911 is displaced in the axial direction during vibration to become smaller (i.e., contracted). In some embodiments, the displacement variation of the first piezoelectric element 1911 along the axial direction during vibration may be controlled by the polarization direction of the first piezoelectric element 1911 and the electrode polarity of the electrical signal, and may be particularly described with reference to fig. 20A and 20B of the present specification.

In some embodiments, the piezoelectric element 1910 may include a plurality of first piezoelectric elements 1911, e.g., 4, 6, 8, etc. The plurality of first piezoelectric elements 1911 may be connected in sequence in the axial direction, and the mass element 1920 is connected to each of the plurality of first piezoelectric elements 1911 through a plurality of elastic elements 1930 (e.g., divided into multiple layers), respectively. Adjacent layers of elastic elements in the multilayer elastic element may provide opposite rotational shear stresses to the mass element 1920. In some embodiments, the number of mass elements 1920 may be plural, and each of the plurality of mass elements 1920 may be connected to one of the first piezoelectric elements 1911 by a plurality of elastic elements 1930.

Fig. 20A is an exemplary circuit diagram of a first piezoelectric element shown according to some embodiments of the present description. Referring to fig. 20A, polarities of connection surfaces of the two first piezoelectric elements 1911 may be the same, and polarities of electrodes of electric signals of the connection surfaces may be the same. For convenience of description, the two first piezoelectric elements 1911 may be referred to as an upper piezoelectric element 19111 and a lower piezoelectric element 19112, respectively. In some embodiments, when the upper piezoelectric element 19111 is connected to the lower piezoelectric element 19112, the upper piezoelectric element 19111 may have an upper connecting surface 2010 and the lower piezoelectric element 19112 may have a lower connecting surface 2020. In some embodiments, when the polarization direction of the upper layer piezoelectric element 19111 is the same as the polarization direction of the lower layer piezoelectric element 19112 (as shown by the arrow in fig. 20A), the polarity of the electrode of the upper layer connection surface 2010 to which the electrical signal is applied (e.g., positive or negative) may be the same as the polarity of the electrode of the lower layer connection surface 2020 to which the electrical signal is applied. In this arrangement, the direction of the electrical potential inside the upper piezoelectric element 19111 may be opposite to the direction of the electrical potential inside the lower piezoelectric element 19112.

By providing the upper and lower piezoelectric elements 19111, 19112 with the same polarization direction, the upper and lower piezoelectric elements 19111, 19112 may be displaced in opposite directions when the upper and lower piezoelectric elements 19111, 19112 are connected to an electrical potential (or electrical signal) in opposite directions.

Fig. 20B is another exemplary circuit diagram of a first piezoelectric element shown according to some embodiments of the present description. Referring to fig. 20B, polarities of connection surfaces of the two first piezoelectric elements may be opposite, and polarities of electrodes of electric signals of the connection surfaces may be opposite. In some embodiments, the upper piezoelectric element 19113 may have an upper connection face 2030 and the lower piezoelectric element 19114 may have a lower connection face 2040 when the upper piezoelectric element 19113 is connected to the lower piezoelectric element 19114. When the polarization direction of the upper piezoelectric element 19112 is opposite to the polarization direction of the lower piezoelectric element 19114 (as shown by the arrow in fig. 20B), the polarity of the electrode (e.g., positive or negative) of the upper layer connection surface 2030 to which the electrical signal is supplied may be opposite to the polarity of the electrode of the lower layer connection surface 2040 to which the electrical signal is supplied. In this arrangement, the direction of the potential inside the upper piezoelectric element 19111 may be the same as the direction of the potential inside the lower piezoelectric element 19112.

By providing the upper piezoelectric element 19113 opposite the polarization of the lower piezoelectric element 19114, the upper piezoelectric element 19113 and the lower piezoelectric element 19114 can be displaced in opposite directions when the upper piezoelectric element 19113 and the lower piezoelectric element 19114 are connected to the same directional potential (or electrical signal).

Fig. 21 is an exemplary block diagram of an acoustic output device according to some embodiments of the present description. The structure of the acoustic output device 2100 shown in fig. 21 is similar to that of the acoustic output device 1200 shown in fig. 12, except that the structure of the piezoelectric element is different. The piezoelectric element 1210 of the acoustic output device 1200 has a single-layer double-ring structure, and the piezoelectric element 2110 of the acoustic output device 2100 has a double-layer double-ring structure.

Referring to fig. 21, in some embodiments, one or more piezoelectric elements 2110 may include two first piezoelectric elements 2111 and two second piezoelectric elements 2112, the two first piezoelectric elements 2111 being distributed up and down along the axis direction and being connected to each other, and the two second piezoelectric elements 2112 being located inside the first ring structure and being distributed up and down along the axis direction and being connected to each other. The axes of the two second piezoelectric elements 2112 and the axes of the two first piezoelectric elements 2111 may coincide, and the projection of the two second piezoelectric elements 2112 in the axial direction is located inside the projection of the first annular structure of the two first piezoelectric elements 2111 in the axial direction.

In some embodiments, the two second piezoelectric elements 2112 may be connected to the two first piezoelectric elements 2111 through at least one of the one or more elastic elements. In some embodiments, the resilient element may comprise an outer ring resilient element 2132, the outer ring resilient element 2132 being located between the first annular structure and the second annular structure. The outer ring elastic element 2132 may include two elastic elements, and the two first piezoelectric elements 2111 and the two second piezoelectric elements 2112 are connected by two elastic elements in the outer ring elastic element 2132, respectively. In some embodiments, the outer ring elastic element 2132 may also have a certain thickness along the axial direction of the second ring structure, and the two first piezoelectric elements 2111 and the two second piezoelectric elements 2112 may be connected by one outer ring elastic element 2132.

In some embodiments, referring to fig. 21, at least a portion of the mass element 2120 may be located inside a second annular structure of the second piezoelectric element 2112 (as shown in fig. 21). The mass element 2120 may be connected to the two second piezoelectric elements 2112 via at least one of the one or more elastic elements 2130, respectively. For example, the resilient element 2130 may comprise an inner ring resilient element 2131, the inner ring resilient element 2131 being located between the second annular structure and at least a portion 2120 of the mass element. The projection of the connection point of the mass element 2120 with the inner ring elastic element 2131 in the axial direction is located within the projection of the second annular structure in the axial direction. The inner ring elastic member 2131 may include two elastic members arranged in the axial direction, and the mass member 2120 is connected to the two second piezoelectric members 2112 through two of the inner ring elastic members 2131, respectively. In some embodiments, the inner ring elastic element 2131 may also have a certain thickness along the axial direction of the first ring structure, and the mass element 2120 and the two second piezoelectric elements 2112 may be connected by one inner ring elastic element 2131.

In some embodiments, the shape of the inner ring elastic element 2131 and the outer ring elastic element 2132 may not be limited to the S shape as shown in fig. 21, but may be other shapes, such as a dogleg shape, spline shape, arc shape, straight shape, and the like. In some embodiments, the inner ring resilient element 2131 and the outer ring resilient element 2132 may also include a helical structure. In some embodiments, the arrangement between the rotation of the tangential stress provided by the inner ring elastic element 2131 to the mass element 2120 and the rotation of the tangential stress provided by the outer ring elastic element 2132 to the mass element 2120, and the arrangement of the rotation of the tangential stress provided by two of the inner ring elastic element 2131 and/or the outer ring elastic element 2132 to the mass element 2120, may be referred to elsewhere in this specification and will not be described again.

In some embodiments, when at least a portion of the mass element 2120 is located inside the second piezoelectric element 2112, one end of the first piezoelectric element 2111 in the axial direction may be fixed, and the other end is connected to the second piezoelectric element 2112 through the outer ring elastic element 2132. For example, the outer ring elastic element 2132 may include two elastic elements arranged in the axial direction, and the two first piezoelectric elements 2111 are connected to the two second piezoelectric elements 2112 through two elastic elements in the outer ring elastic element 2132, respectively. In this case, the second piezoelectric element 2112 may function as a piezoelectric free ring, and the first piezoelectric element 2111 may function as a piezoelectric fixed ring.

In some embodiments, at least a portion of the mass element 2120 may also be located outside of the first annular structure of the first piezoelectric element 2111. For example, at least a portion of the mass element 2120 may comprise an annular structure. The projection of the annular structure of mass element 2120 along the axial direction may be located outside the projection of the first annular structure along the axial direction. The mass element 2120 may be connected to the two first piezoelectric elements 2111 by at least one of the one or more elastic elements 2130, respectively. For example, the mass element 2120 may be connected to two first piezoelectric elements 2111 via two of the outer ring elastic elements 2132, respectively.

In some embodiments, when the mass element 2120 is located outside the first piezoelectric element 2111, one end of the second piezoelectric element 2112 in the axial direction may be fixed, and the other end is connected to the first piezoelectric element 2111 through the inner ring elastic element 2131. In this case, the second piezoelectric element 2112 may function as a piezoelectric fixed ring, and the first piezoelectric element 2111 may function as a piezoelectric free ring.

In some embodiments, at least a portion of the mass element 2120 may also be located between the first annular structure of the first piezoelectric element 2111 and the second annular structure of the second piezoelectric element 2112. The projection of the annular structure of the mass element 2120 along the axial direction may be located between the projections of the first annular structure and the second annular structure along the axial direction. The mass element 2120 may be connected to two first piezoelectric elements 2111 and two second piezoelectric elements 2112, respectively, via one or more elastic elements 2130. For example, the mass element 2120 may be connected to the two first piezoelectric elements 2111 via the outer ring elastic element 2132, respectively, and the mass element 2120 may be connected to the two second piezoelectric elements 2112 via the inner ring elastic element 2131, respectively.

In some embodiments, when the mass element 2120 is located between the second piezoelectric element 2112 and the first piezoelectric element 2111, the first piezoelectric element 2111 or the second piezoelectric element 2112 has a fixed end in the axial direction. In this case, one of the first piezoelectric element 2111 and the second piezoelectric element 2112 may function as a piezoelectric free ring, and the other may function as a piezoelectric fixed ring.

When the piezoelectric element 2110 has a double-layer structure, the piezoelectric element 2110 may not have a fixed end in the axial direction, and thus the vibration device 2100 may be more easily used in a bone conduction headset in which it is difficult to find a strict fixing boundary.

Note that, when the piezoelectric element 2110 has a double-layer structure, the elastic element may have a double-layer structure, and the rotation of the shear stress provided by the two elastic elements may be opposite in the double-layer structure of the elastic element. In some embodiments, the piezoelectric element may also be a multi-layer multi-ring structure, such as a 4-layer 4-ring structure, or the like. The piezoelectric element of the multilayer multi-ring structure is similar to the piezoelectric element of the double-layer dual-ring structure, and will not be described here again.

Fig. 22 is a plot of the frequency response of an acoustic output device according to some embodiments of the present description. The curve 2210 may represent a frequency response curve of the acoustic output device when the piezoelectric element is in a single-layer single-ring structure, the curve 2220 represents a frequency response curve of the acoustic output device when the piezoelectric element is in a single-layer double-ring structure, and the first piezoelectric element has a fixed end along the axial direction. In some embodiments, a third resonance peak other than the first resonance peak and the second resonance peak may be formed in the frequency response curve of the acoustic output device by providing a piezoelectric free ring in the acoustic output device. For example, the curve 2210 and the curve 2220 are compared, the curve 2220 may form a third resonance peak other than the first resonance peak and the second resonance peak, and the frequency of the third resonance peak is located between the frequency of the first resonance peak and the frequency of the second resonance peak.

With continued reference to fig. 22, curve 2230 represents the frequency response curve of an acoustic output device having a piezoelectric element with a double-layer double-ring structure and a first piezoelectric element with a fixed end in the axial direction, and curve 2240 represents the frequency response curve of an acoustic output device having a piezoelectric element with a double-layer double-ring structure and a piezoelectric element without a fixed end in the axial direction. In some embodiments, the sensitivity of the acoustic output device in the audible frequency range may be improved by providing a piezoelectric element in a dual layer counter-vibrating structure. For example, comparing curve 2220 and curve 2230, curve 2230 is offset upward as a whole as compared to curve 2220, with the sensitivity of curve 2230 being higher than the sensitivity of curve 2220. In some embodiments, by providing the first piezoelectric element and the second piezoelectric element each in a free loop state, the first piezoelectric element and the second piezoelectric element (and the elastic element for connection) together with the mass element form an overall mass, thereby shifting the low frequency resonance peak of the acoustic output device to the right. For example, comparing curve 2230 and curve 2240, the first resonance peak of curve 2240 is shifted rightward with respect to the first resonance peak of curve 2230, and the amplitude of the first resonance peak of curve 2240 and the amplitude of the frequency band before the first resonance peak are increased, thereby improving the low frequency performance.

In some embodiments, when the piezoelectric element is provided in a two-layer structure, the structures of the two piezoelectric elements may be identical. For example, the piezoelectric element may include two first piezoelectric elements arranged in order in the axial direction, and the structures of both piezoelectric elements are ring-shaped structures. In some embodiments, when the piezoelectric element is provided in a two-layer structure, the structures of the two piezoelectric elements may also be different. For example, the piezoelectric element of any one of the two layers of piezoelectric elements may be of a ring-shaped structure, and the other layer of piezoelectric element may be of a piezoelectric beam structure.

Fig. 23 is an exemplary block diagram of an acoustic output device according to some embodiments of the present description. As shown in fig. 23, the acoustic output device 2300 may include one or more piezoelectric elements 2310, a mass element 2320, and one or more elastic elements 2330. In some embodiments, the one or more piezoelectric elements 2310 may include a piezoelectric beam (or beam structure) 2340. The piezoelectric beams 2340 may include a substrate 2343 and piezoelectric sheets (e.g., piezoelectric sheets 2341 and 2342). In some embodiments, a piezoelectric beam 2340 may be coupled to the mass 2320. In some embodiments, the piezoelectric beam 2340 may be located at a side of the mass element 2320 away from the piezoelectric element 2310 in an axial direction of the ring-shaped structure of the piezoelectric element 2310 and connected with the mass element 2320. In some embodiments, the piezoelectric beams 2340 may be plate-like structures with the plate-like structure faces (i.e., the largest area surfaces) disposed parallel to the annular end faces of the annular structure of the piezoelectric element 2310.

In some embodiments, the piezoelectric sheets may include at least one first piezoelectric sheet 2341 and at least one second piezoelectric sheet 2342. The first piezoelectric sheet 2341 and the second piezoelectric sheet 2342 are provided on both sides of the piezoelectric beam 2340 in the axial direction of the annular structure of the piezoelectric element 2310, respectively. For example, the first piezoelectric sheet 2341 may be disposed on a side of the piezoelectric beam 2340 away from the piezoelectric element 2310 in the axial direction, and the second piezoelectric sheet 2342 may be disposed on a side of the piezoelectric beam 2340 close to the piezoelectric element 2310 in the axial direction.

In some embodiments, the first piezoelectric sheet 2341 and/or the second piezoelectric sheet 2342 may be configured to deform based on the electrical signal, and a direction of the deformation (also referred to as a displacement output direction) is perpendicular to an electrical direction of the first piezoelectric sheet 2341 and/or the second piezoelectric sheet 2342. The electrical direction of the first piezoelectric sheet 2341 (and/or the second piezoelectric sheet 2342) is parallel to the electrical direction of the first piezoelectric sheet 2341 (and/or the second piezoelectric sheet 2342). In some embodiments, the substrate 2343 may warp along the electrical direction of the piezoelectric sheet based on the deformation of the piezoelectric sheet to generate mechanical vibration. The direction of the mechanical vibration is parallel to the electrical direction of the first piezoelectric sheet 2341 (and/or the second piezoelectric sheet 2342).

In some embodiments, the electrical directions of the first and second piezoelectric sheets 2341 and 2342 may be reversed along the axial direction of the ring structure. That is, in the axial direction of the annular structure of the piezoelectric element 2310, the electrical direction of the first piezoelectric sheet 2341 is opposite to the electrical direction of the second piezoelectric sheet 2342. The displacement output directions of the first and second piezoelectric sheets 2341 and 2342 may be perpendicular to the respective electrical directions. In some embodiments, when the electrical direction of the first piezoelectric plate 2341 is opposite to the electrical direction of the second piezoelectric plate 2342, and the first piezoelectric plate 2341 and the second piezoelectric plate 2342 are simultaneously connected to the voltage signal in the same direction, the first piezoelectric plate 2341 and the second piezoelectric plate 2342 may generate displacement in opposite directions, so that the piezoelectric beam 2340 vibrates. The vibration direction of the piezoelectric beam 2340 is perpendicular to the displacement output direction of the first and second piezoelectric sheets 2341 and 2342. For example, the first piezoelectric sheet 2341 may contract in the direction perpendicular to the axis of the ring structure, and the second piezoelectric sheet 2342 may elongate in the direction perpendicular to the axis of the ring structure, so that the piezoelectric beam 2340 generates vibration in the direction of the axis of the ring structure. In some embodiments, the piezoelectric beams 2340 may be coupled to the mass 2320 and output vibrations through the mass 2320. In some embodiments, the piezoelectric beam 2340 may be directly connected to the mass element 2320 such that the resonance peak of the acoustic output device 2300 includes a high-frequency resonance peak (e.g., frequency range of 2kHz-20 kHz) generated by the resonance of the piezoelectric beam 2340, i.e., the piezoelectric beam 2340 constitutes a high-frequency unit of the acoustic output device 2300.

In some embodiments, the ring-structured piezoelectric element 210 may also include a piezoelectric sheet that is in the form of a block (e.g., a ring-shaped block). The piezoelectric sheet may generate mechanical vibration based on the electric signal, and a direction of the mechanical vibration of the piezoelectric sheet is parallel to an electrical direction of the piezoelectric sheet. In some embodiments, when the piezoelectric patch is connected to a voltage signal along the axis of the ring structure, the piezoelectric patch may vibrate along the axis of the ring structure, thereby producing a displacement output along the axis of the ring structure.

In some embodiments, the elastic element 2330 of the acoustic output device 2300 may have a double-X configuration as shown in fig. 23, or may have other types of structures with reverse symmetry, such as a single-X configuration, a parallel double-X configuration, a spiral configuration, etc.

Fig. 24 is an exemplary block diagram of an acoustic output device according to some embodiments of the present description. The structure of the acoustic output device 2400 in fig. 24 is substantially the same as the structure of the acoustic output device 2300 in fig. 23, except for the structure and number of mass elements and the manner of connection of the mass elements to the piezoelectric beams.

Referring to fig. 24, in some embodiments, the mass elements may include a first mass element 2421 and a second mass element 2422. Wherein the first mass element 2421 may be coupled to a central portion of the piezoelectric beam 2340 by one or more elastic elements 2330. In some embodiments, the first mass element 2421 may also be connected to one or more piezoelectric elements 2310 by elastic elements 2330, the piezoelectric elements 2310 including a ring structure, and the vibration direction of the piezoelectric elements 2310 being parallel to the axial direction of the ring structure. In some embodiments, a second mass element 2422 may be connected to each end of the piezoelectric beam 2340. Vibrations of the acoustic output device 2400 may be output through the second mass 2422 at the end of the piezoelectric beam 2340. In some embodiments, vibrations of the acoustic output device 2400 may also be output through the first mass element 2421. In some embodiments, the connection of the first mass element 2421 to the piezoelectric beam 2340 by one or more elastic elements 2330 may form a low frequency unit of the acoustic output device 2400 and the piezoelectric element 2310 having a ring structure may form a high frequency unit of the acoustic output device 2400.

In some embodiments, the first mass element 2421 may also be coupled to other locations of the piezoelectric beam 2340 (e.g., near an end of the piezoelectric beam 2340) by one or more elastic elements 2330. In some embodiments, both ends of the piezoelectric beam 2340 may also pass through one or more elastic elements 2330 and the second mass element 2422.

While the basic concepts have been described above, it will be apparent to those skilled in the art that the foregoing detailed disclosure is by way of example only and is not intended to be limiting. Although not explicitly described herein, various modifications, improvements and adaptations of the application may occur to one skilled in the art. Such modifications, improvements, and modifications are intended to be suggested within the present disclosure, and therefore, such modifications, improvements, and adaptations are intended to be within the spirit and scope of the exemplary embodiments of the present disclosure.

Meanwhile, the present application uses specific words to describe embodiments of the present application. Reference to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic is associated with at least one embodiment of the application. Thus, it should be emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various positions in this specification are not necessarily referring to the same embodiment. Furthermore, certain features, structures, or characteristics of one or more embodiments of the application may be combined as suitable.

Finally, it should be understood that the embodiments described herein are merely illustrative of the principles of the embodiments of the present application. Other variations are also possible within the scope of the application. Thus, by way of example, and not limitation, alternative configurations of embodiments of the application may be considered in keeping with the teachings of the application. Accordingly, the embodiments of the present application are not limited to the embodiments explicitly described and depicted herein.

Claims

1. An acoustic output device, comprising:

a piezoelectric element for converting an electric signal into mechanical vibration;

a resilient element comprising a plurality of bar structures, each bar structure comprising one or more bending regions; and

a mass element connected to the piezoelectric element via the elastic element, receiving the mechanical vibration to generate an acoustic signal, wherein

The plurality of rod structures are located in the same plane perpendicular to the vibration direction of the mass element, and the projection of the plurality of rod structures along the vibration direction of the mass element is provided with two symmetry axes perpendicular to each other.

2. The acoustic output device of claim 1, wherein the number of the plurality of rod structures is 4.

3. The acoustic output device of claim 2, wherein the shape of the stem structure comprises at least one of a dogleg shape, an S-shape, a spline-shape, an arc shape, and a straight shape.

4. The acoustic output device of claim 1, wherein at least one of the plurality of rod structures comprises a plurality of segments, the plurality of segments having opposite bending directions.

5. The acoustic output device of claim 1, further comprising a second elastic element, the elastic element and the second elastic element being respectively connected to the mass element.

6. The acoustic output device of claim 5, wherein the second elastic element is located on the same plane as the elastic element, the plane being perpendicular to the vibration direction of the mass element, and a central axis of the second elastic element is disposed parallel to a central axis of the elastic element.

7. The acoustic output device of claim 5, wherein the second elastic element is disposed coaxially with the elastic element.

8. The vibration apparatus of claim 1, wherein the elastic element and the mass element resonate to produce a first resonant peak; the piezoelectric element resonates to produce a second resonance peak.

9. The vibration apparatus of claim 8 wherein the first resonant peak has a frequency in the range of 50Hz-2000 Hz.

10. The vibration apparatus of claim 8 wherein the second resonance peak has a frequency range of 1000Hz-50000 Hz.