TWI843497B - An acoustic output device - Google Patents

Abstract

The present disclosure may disclose an acoustic output device, including: piezoelectric elements for converting electrical signals into mechanical vibrations; the upper elastic element and the lower elastic element respectively comprise a plurality of rod structures, each of which comprises one or more bending regions; and the mass element, the upper elastic element and the lower elastic element are respectively connected with the mass element and the piezoelectric element, the upper elastic element and the lower elastic element are distributed up and down along the vibration direction of the mass element, and the upper elastic element or the lower elastic element along the vibration direction of the mass element has at least one axis of symmetry. By setting the shape and structure of the elastic element, the elastic element can provide the shear stress with opposite curl on the plane perpendicular to the vibration direction of the mass element, thus inhibiting the rotation mode generated by the rotation of the mass element and/or piezoelectric element in the plane, then the resonant valley in the frequency response curve of the acoustic output device is improved due to the rotational mode.

Description

Acoustic output device

The present invention relates to the field of acoustic technology, and in particular to an acoustic output device.

This invention claims priority to Chinese patent application No. 202210361137.4 filed on April 7, 2022, the entire contents of which are incorporated herein by reference.

Piezoelectric speakers usually use the reverse piezoelectric effect of piezoelectric ceramic materials to generate vibrations to radiate sound waves. Compared with transmission electromagnetic speakers, piezoelectric speakers have the advantages of high electromechanical energy conversion efficiency, low energy consumption, small size, and high integration. Under the current trend of device miniaturization and integration, piezoelectric speakers have extremely broad prospects and future. However, compared with traditional electromagnetic speakers, piezoelectric speakers have poor low-frequency sound quality due to the poor low-frequency response of piezoelectric acoustic devices. At the same time, piezoelectric speakers have many vibration modes in the audible domain, which also prevents them from forming a relatively flat frequency curve.

Therefore, it is necessary to propose an acoustic output device to reduce the vibration mode in the audible domain and at the same time improve the low-frequency response of the acoustic output device.

The embodiment of the specification provides an acoustic output device, including a piezoelectric element for converting an electrical signal into mechanical vibration; an upper elastic element and a lower elastic element, wherein the upper elastic element and the lower elastic element respectively include a plurality of rod structures, each of which includes one or more bending regions; and a mass element, wherein the upper elastic element and the lower elastic element are respectively connected to the mass element and the piezoelectric element, and the mass element receives the mechanical vibration to generate a sound signal, wherein the upper elastic element and the lower elastic element are distributed up and down along the vibration direction of the mass element, and the projection of the upper elastic element or the lower elastic element along the vibration direction of the mass element has at least one symmetry axis.

In order to more clearly explain the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present invention. For ordinary technicians in this field, the present invention can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

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

As shown in the present invention and patent application, unless the context clearly indicates an exception, the words "a", "an", "an" and/or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate that the steps and elements that have been clearly identified are included, and these steps and elements do not constitute an exclusive list. The method or apparatus may also include other steps or elements.

The present invention uses flow charts to illustrate the operations performed by the system according to the embodiments of the present invention. It should be understood that the previous or subsequent operations are not necessarily performed in exact order. Instead, the steps can be processed in reverse order or simultaneously. At the same time, other operations can be added to these processes, or one or more operations can be removed from these processes.

The acoustic output device provided in the embodiments of this specification may include but is not limited to bone conduction speakers, air conduction speakers, bone conduction hearing aids or air conduction hearing aids, etc. The acoustic output device provided in the embodiments of this specification may include piezoelectric elements. Piezoelectric elements can be used to convert electrical signals into mechanical vibrations. Piezoelectric elements can convert input voltage into mechanical vibrations under the action of the inverse piezoelectric effect, thereby outputting vibration displacement. Therefore, an acoustic output device that outputs displacement through a piezoelectric element is also called a piezoelectric acoustic output device. The working mode of the piezoelectric element in the piezoelectric acoustic output device usually adopts the D33 working mode and the D31 working mode. In the D33 working mode, the polarization direction of the piezoelectric element is the same as the displacement output direction. When the piezoelectric element is in the d31 working mode, the polarization direction of the piezoelectric element is perpendicular to the displacement output direction. Since piezoelectric elements usually have a higher resonant frequency, piezoelectric acoustic output devices can usually improve high-frequency output, but piezoelectric elements have poor low-frequency response and usually have more vibration modes in the audible range (such as 20 Hz-20000 Hz), making it difficult to form a relatively flat frequency response curve, thereby affecting the sound quality of the acoustic output device.

In order to solve the problem of poor low-frequency response of the piezoelectric acoustic output device and more modes in the audible frequency range, the acoustic output device provided in the embodiment of the present specification may include a mass element and an elastic element. The first resonance peak is constructed in the low-frequency range (for example, 20 Hz-2000 Hz) by using the combined structure of the elastic element and the mass element, and the second resonance peak is constructed in the higher frequency range (for example, 1000 Hz-20000 Hz) by using the piezoelectric element, so that a straight curve can be formed between the first resonance peak and the second resonance peak. At the same time, by setting the shape and structure of the elastic element, the elastic element can provide a shear stress with an opposite rotation on a plane perpendicular to the vibration direction of the mass element, thereby suppressing the rotation mode generated by the rotation of the mass element and/or the piezoelectric element in the plane, and further improving the resonant valley generated by the rotation mode in the frequency curve of the acoustic output device.

FIG. 1 is an exemplary module diagram of an acoustic output device according to some embodiments of the present specification. In some embodiments, the acoustic output device 100 may include a piezoelectric element 110, a mass element 120, and an elastic element 130. In some embodiments, the mass element 120 may be connected to the piezoelectric element 110 through the elastic 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 multiple, 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 multiple. In some embodiments, the mass element 120 may be connected to one piezoelectric element 110. In some embodiments, the mass element 120 may also be connected to multiple piezoelectric elements 110 respectively. In some embodiments, multiple piezoelectric elements 110 may be connected to each other. In some embodiments, multiple piezoelectric elements 110 may be directly connected to each other. In some embodiments, multiple piezoelectric elements 110 may also be connected to each other through 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 materials having a piezoelectric effect, such as piezoelectric ceramics and piezoelectric polymers. In some embodiments, the piezoelectric element 110 may be used to convert an electrical signal into a 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 a 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 the piezoelectric element 110 may be one or more. In some embodiments, when the number of the piezoelectric element 110 is more than one, the multiple piezoelectric elements 110 may be connected via the elastic element 130. In some embodiments, any one of the piezoelectric elements 110 connected to each other via the elastic element 130 may be connected to the mass element 120 via another elastic element 130. In some embodiments, the multiple piezoelectric elements 110 may also be connected in series along the vibration direction of the multiple piezoelectric elements 110 to form a whole, and the series-connected piezoelectric elements 110 may be connected to the mass element 120 via 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 be an annular structure, and the annular structure may be reciprocated along the axial direction to generate mechanical vibration. For another example, the piezoelectric element 110 may include a piezoelectric sheet and a beam structure, and the piezoelectric sheet may be reciprocated along a direction perpendicular to the polarization direction of the piezoelectric sheet, thereby driving the beam structure to bend 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 along the polarization direction of the piezoelectric element 110 under the action of an electrical signal. As an example only, the piezoelectric element 110 may include an annular structure, and the annular structure may be a columnar structure with an annular end face. In some embodiments, the polarization direction of the piezoelectric element 110 may be parallel to the axial direction of the annular structure, and the piezoelectric element 110 may vibrate along the axial direction of the annular structure of the piezoelectric element 110 under the action of an electrical signal. The axis of the annular structure can be a virtual line connecting the centroids of the two annular end faces of the columnar structure and connecting the centroids of any cross-sections 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 face of the annular structure can include but is not limited to a circular ring, an elliptical ring, a curved ring or a polygonal ring. In some embodiments, the polarization direction of the piezoelectric element 110 is parallel to the axial direction of the annular structure. Under the action of an electrical signal, the piezoelectric element 110 can vibrate along the axial direction of the annular structure of the piezoelectric element 110.

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 an electrical signal, the piezoelectric sheet may undergo reciprocating deformation, thereby driving the beam structure to vibrate. As an example only, the piezoelectric sheet may undergo reciprocating deformation in a direction perpendicular to the polarization direction of the piezoelectric sheet under the action of an electrical signal. The reciprocating deformation may further drive the beam structure to warp along the polarization direction of the piezoelectric sheet, generating mechanical vibration. 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 with a certain mass. In some embodiments, the mass element 120 may be used as a vibration plate or a diaphragm of the acoustic output device 100, so that the acoustic output device 100 outputs vibrations through the mass element 120. In some embodiments, the material of the mass element 120 may be a metal material or a non-metal material. The metal material may include but is not limited to steel (e.g., stainless steel, carbon steel, etc.), light alloy (e.g., aluminum alloy, cobalt, magnesium alloy, titanium alloy, etc.), etc., or any combination thereof. The non-metal material may include but is not limited to polymer materials, glass fibers, carbon fibers, graphite fibers, silicon carbide fibers, etc. In some embodiments, the projection of the mass element 120 along the vibration direction of the mass element 120 may be a regular and/or irregular polygon such as a circle, a ring, a rectangle, a pentagon, a hexagon, etc.

In some embodiments, the mass element 120 can be connected to the piezoelectric element 110 through the elastic element 130, and the mass element 120 receives the mechanical vibration 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 connected thereto can cause the acoustic output device 100 to generate a first resonance peak. The magnitude of the first resonance frequency corresponding to the first resonance 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) can be expressed by formula (1): , (1) wherein 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. According to 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 connected to the inner side of the piezoelectric element 110 through the elastic element 130. In some embodiments, when the piezoelectric element 110 vibrates based on an electrical signal, the vibration is transmitted to the mass element 120 through the elastic element 130, so that the mass element 120 vibrates 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 along the axial direction of the piezoelectric element 110 is located within the projection of the piezoelectric element 110 along the axial direction of the piezoelectric element 110.

In some embodiments, the mass element 120 may be connected to the outer side of the piezoelectric element 110 through the elastic element 130. For example, at least a portion of the mass element 120 is a ring structure, and the mass element 120 may be connected to the piezoelectric element 110 through the ring structure. For example, the ring structure may be located outside the piezoelectric element 110, and the inner diameter of the ring structure may be greater than the outer diameter of the ring structure of the piezoelectric element 110, so that the projection of the ring structure of the mass element 120 along the axial direction of the piezoelectric element 110 may be located outside 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 a ring structure, and the projection of the ring structure of the mass element 120 along the axial direction of the piezoelectric element 110 may be located between the 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 in the shape of a ring, a cover plate may be provided on one side of the mass element 120 that is away from the piezoelectric element 110 along the axial direction of the piezoelectric element 110. The cover plate may seal the side of the mass element 120 that is away from the piezoelectric element 110 along the axial direction of the piezoelectric element 110. For example, when the mass element 120 is in the shape of a ring, the cover plate may be a circular structure, and the periphery of the cover plate is connected to the side of the mass element 120 that is away from the piezoelectric element 110 along the axial direction of the piezoelectric element 110. By arranging a cover plate on a side of the mass element 120 away from the piezoelectric element 110 along the axial direction of the piezoelectric element 110, the cover plate can be used as a vibration plate for transmitting a vibration signal. In some embodiments, the cover plate can also be used to connect the mass element 120 to other structures of the acoustic output device 100, such as a diaphragm, so that the acoustic output device 100 drives the diaphragm to vibrate through the mass element 120.

The elastic element 130 may be an element that can undergo elastic deformation under the action of an external load. In some embodiments, the elastic element 130 may be a material with good elasticity (i.e., easy to undergo elastic deformation), so 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, and gel materials. In some embodiments, the number of elastic elements 130 may be one or more. In some embodiments, the mass element 120 may be connected to the piezoelectric element 110 through an elastic element 130. For example, the shape of the elastic element 130 may be annular, and the mass element 120 and the piezoelectric element 110 may be connected through the annular elastic element 130. In some embodiments, the mass element 120 may be connected to the piezoelectric element 110 via a plurality of elastic elements 130. For example, the elastic element 130 may include a rod structure, and the plurality of elastic elements 130 are distributed along the circumference of the piezoelectric element 110 and connected to 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 vibrates. In some embodiments, the elastic element 130 may also be a connecting rod provided on the vibration-transmitting sheet, thereby making the processing of the acoustic output device 100 simpler and faster.

In some embodiments, the elastic element 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 multiple elastic elements are located in different planes perpendicular to the axial direction of the piezoelectric element 110.

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

In some embodiments, during the vibration of the acoustic output device 100, since the elastic element 130 has a curved shape, the elastic element 130 may provide shear stress to the mass element 120 (and/or the piezoelectric element 110) in the plane where the curved shape is located. When the shear stress rotation provided by multiple elastic elements 130 to the mass element 120 is the same, the mass element 120 (and/or the piezoelectric element 110) may have a tendency to rotate around 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) that is tangential to any cross section of the mass element 120 that is perpendicular to the vibration direction of the mass element 120. In some embodiments, on a plane perpendicular to the vibration direction of the mass element 120, at least two parts of the elastic element 130 (for example, the upper elastic element and the lower elastic element in the elastic element, the first bending area 211 and the second bending area 212 in the rod structure 210, etc.) can provide shear stress with opposite rotation. In some embodiments, the elastic element 130 is connected to the mass element 120 (and/or the piezoelectric element 110). In order to prevent the mass element 120 (and/or the piezoelectric element 110) connected to the elastic element 130 from generating a rotational tendency, at least two parts of the elastic element 130 can provide shear stress with opposite rotation to the mass element 120 (and/or the piezoelectric element 110). The curl (also called the curl vector) can be a vector operator used to measure the rotational property of the shear stress vector field. The magnitude of the vector operator can measure the degree of rotation of the shear stress vector field, and the direction of the vector operator can measure the rotation direction of the shear stress vector field. The direction of the curl vector can be determined based on the rotation direction and the right-hand rule. For example, when the piezoelectric element 110 rotates due to the shear stress provided by the elastic element 130, according to the right-hand rule, the bending direction of the four fingers is consistent with the rotation (or rotation trend) direction of the annular structure. At this time, the direction of the thumb is the direction of the curl vector. In some embodiments, the elastic element 130 may include at least two parts, and the rotation of the shear stress provided by the at least two parts to the mass element 120 (and/or the piezoelectric element 110) may be opposite, so that they can offset each other, so that the shear stress provided by the elastic element 130 as a whole to the mass element 120 is zero or close to zero, thereby preventing or reducing the rotation of the mass element 120.

In some embodiments, the elastic element 130 may include a plurality of rod structures, each of which includes one or more bending regions (e.g., the first bending region 211, the second bending region 212, etc. shown in FIG. 2 ), and the shear stress provided by each bending region corresponds to a curl. In some embodiments, the directions of the curls corresponding to the shear stress provided by each bending region in the one or more bending regions may be the same or different. In some embodiments, the directions of the curls corresponding to the shear stress provided by each bending region may be opposite.

In some embodiments, when there are multiple elastic elements 130, the curls corresponding to the shear stress provided by the bending regions of adjacent elastic elements 130 may be different. In some embodiments, when the elastic elements 130 are a single-layer structure, the projections of the multiple elastic elements 130 along the vibration direction of the mass element 120 may have two mutually perpendicular symmetry axes, so that the curls corresponding to the shear stress provided by the bending regions of adjacent elastic elements 130 are different.

In some embodiments, when the elastic element 130 is a multi-layer structure, the curl corresponding to the shear stress provided by the bending regions of the elastic elements 130 of different layers may be different. In some embodiments, the elastic element 130 may be a double-layer structure, and the curl of the shear stress provided by the double-layer structure may be opposite. As an example only, the elastic element 130 may include a first spiral structure and a second spiral structure, and the first spiral structure and the second spiral structure respectively connect the mass element 120 and the piezoelectric element 110 in different planes perpendicular to the axis direction of the piezoelectric element 110. In some embodiments, the axes of the first spiral structure and the second spiral structure may be the same, and the spiral directions may be opposite. By setting the first spiral structure and the second spiral structure with opposite spiral directions, the shear stress provided by the elastic elements 130 of different layers to the mass element 120 (and/or the piezoelectric element 110) can have opposite curl directions, so that the shear stress provided by the elastic elements 130 of different layers to the mass element 120 can offset each other, thereby avoiding the mass element 120 from having a rotation tendency. For more descriptions of the bending area of the elastic element 130 and its setting, please refer to FIG. 2 to FIG. 8B and related descriptions of this specification.

In some embodiments, the acoustic output device 100 may form at least two resonance peaks within the audible frequency range. In some embodiments, the elastic element 130 and the mass element 120 may resonate to generate a first resonance peak; the piezoelectric element 110 may resonate to generate a second resonance peak. In some embodiments, the frequency corresponding to the first resonance peak (also referred to as the first resonance frequency) may be in the low frequency range (e.g., less than 2000 Hz), and the frequency corresponding to the second resonance peak (also referred to as the second resonance frequency) may be in the mid-high frequency range (e.g., greater than 1000 Hz). In some embodiments, the second resonance frequency corresponding to the second resonance peak may be higher than the first resonance frequency corresponding to the first resonance peak. In some embodiments, there is no resonance valley between the second resonance peak and the first resonance peak, and a relatively flat curve may be formed between the first resonance peak and the second resonance peak, thereby improving the sound quality of the output sound of the acoustic output device 100.

In some embodiments, according to formula (1), the frequency range of the first harmonic frequency corresponding to the first harmonic 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 frequency range of the first harmonic frequency corresponding to the first harmonic peak can be 50 Hz-2000 Hz. In some embodiments, in order to improve the sound output of the acoustic output device 100 in a lower frequency range, the frequency range of the first harmonic frequency corresponding to the first harmonic peak can be 50 Hz-1000 Hz.

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

In some embodiments, in order to make the frequency curve of the acoustic output device 100 have a relatively large flat area between the first harmonic peak and the second harmonic peak, thereby ensuring the low-frequency response of the acoustic output device 100 and the sound quality of the output sound, the frequency ratio of the second harmonic frequency corresponding to the second harmonic peak to the first harmonic frequency corresponding to the first harmonic peak may be in the range of 20-200. In some embodiments, the frequency ratio of the second harmonic frequency corresponding to the second harmonic peak to the first harmonic frequency corresponding to the first harmonic peak may be in the range of 50-150.

In some embodiments, the elastic element can be used to connect the piezoelectric element and the mass element to transmit vibration. Therefore, the structural design of the elastic element can affect the vibration characteristics of the acoustic output device. In some embodiments, in order to meet the requirements of the elastic element for the elastic coefficient, the elastic element can be designed into a curved shape to increase the length of the elastic element, thereby reducing the elastic coefficient of the elastic element. In this setting, if the shape of the elastic element has a rotational or asymmetric configuration, the configuration may provide shear stress to the mass element on a plane perpendicular to the vibration direction of the mass element, causing the mass element of the acoustic output device to generate a rotational mode when vibrating, thereby affecting the output of the acoustic output device (which may appear as a harmonic valley in the frequency response curve), and further 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 via 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 distributed symmetrically around the circumference of the mass element, so that when the acoustic output device may generate a rotational mode, the symmetry of the elastic element may be utilized (for example, the rotation of the shear stress provided by the plurality of rod structures in the elastic element to the mass element is opposite) to cancel the rotational modes in anti-phase, thereby reducing or eliminating the resonance valley generated by the rotational mode.

In some embodiments, the shape of the rod structure may include at least one of a broken line, an S shape, a spline curve shape, an arc shape, and a straight line shape. In some embodiments, when the rod structure is in different shapes, the rod structure may have different bending regions, and the shear stress provided to the mass element (and/or piezoelectric element) by different bending regions may correspond to different curls. In some embodiments, the connecting line of the two ends of the rod structure is used as an auxiliary line, and the rod structure may be alternately connected on both sides of the auxiliary line to form sub-segments, and the segment formed by multiple sub-segments with the same alternating regularity is the bending region of the rod structure. Taking the shape of the elastic element as an example, the fold line may first bend toward the first side of the auxiliary line, then bend toward the second side of the auxiliary line, and then bend toward the first side again, and repeat this cycle. When the loop pattern changes, the bending area of the fold line segment ends.

FIG. 2 is an exemplary structural diagram of an elastic element according to some embodiments of the present specification. As shown in FIG. 2 , in some embodiments, the elastic element 200 may include a plurality of rod structures 210, each of which includes one or more bending regions, and the shear stress provided by each bending region corresponds to a curl. For example, each rod structure 210 in the elastic element 200 in FIG. 2 may include two bending regions, namely a first bending region 211 and a second bending region 212, and the first bending region 211 and the second bending region 212 are connected end to 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 that expresses the alternating regularity of the multiple sub-segments on both sides of the auxiliary line. As shown in FIG2 , 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, and the first direction and the second direction are opposite to the auxiliary line of the rod structure 210 (as shown by the dotted line 201 in FIG2 ). In some embodiments, the first direction may be a counterclockwise direction relative to the center of the projection shape of the elastic element in the projection plane along the vibration direction of the piezoelectric element, and the second direction may be a clockwise direction relative to the center of the projection shape of the elastic element in the projection plane along the vibration direction of the piezoelectric element.

In some embodiments, the multiple rod structures 210 of the elastic element 200 may be located in the same plane perpendicular to the vibration direction of the mass element 203. It can also be understood that the multiple rod structures 210 of the elastic element 200 are located in the same plane, which is perpendicular to the vibration direction of the mass element 203.

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

In some embodiments, the curl of the shear stress provided by different bending regions in the rod structure 210 to the mass element 203 may be opposite. As shown in FIG2 , the bending directions of the first bending region 211 and the second bending region 212 are opposite. During the vibration process, the rotation trend directions 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 shear stress provided by the first bending region 211 to the mass element 203 and the curl of the shear stress provided by the second bending region 212 to the mass element 203 may be opposite. For example, the curl of the shear stress provided by the first bending region 211 to the mass element 203 points to the paper plane, and the curl of the shear stress provided by the second bending region 212 to the mass element 203 points to the paper plane.

In some embodiments, the first bending region 211 provides a first tangential stress of a first rotation to the mass element 203, and the second bending region 212 provides a second tangential stress of a second rotation to the mass element 203. The first rotation and the second rotation are in opposite directions. The reverse action between the first tangential stress and the second tangential stress can enable a first rotation mode of the mass element 203 generated by the rotation of the first bending region 211 and a second rotation mode generated by the rotation of the second bending region 211 to offset each other, thereby reducing or eliminating the resonant valley generated by the rotation mode.

In some embodiments, when 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 more bending regions, for example, a third bending region, a fourth bending region, etc. When the rod structure 210 includes a plurality of segments, the curls of the shear stresses provided to the mass element 203 by adjacent segments among the plurality of segments may be opposite.

In some embodiments, the projection of at least one of the plurality of rod structures 210 along the vibration direction of the mass element 203 may have at least one symmetry axis, and the rod structures located on both sides of the symmetry axis provide opposite shear stress curls to the mass element 203. For example, as shown in FIG2 , 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 a symmetry axis 202. The symmetry axis 202 may be a straight line passing through a connection point A between the first bending region 211 and the second bending region 212 and perpendicular to the auxiliary line 201 of the rod structure 210. The rod structures located on both sides of the symmetry axis 202 provide opposite shear stress curls to the mass element 203.

In some embodiments, the elastic element may include a plurality of rod 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 certain manner so that the projections of the plurality of rod structures along the vibration direction of the mass element may have at least two mutually perpendicular symmetry axes.

FIG. 3 is an exemplary structural diagram of an elastic element according to some embodiments of the present specification. In some embodiments, the number of the plurality of rod structures of the elastic element 300 may be an even number (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, a first rod structure 311, a second rod structure 312, a third rod structure 313, and a fourth rod structure 314. The four rod structures may be arranged to form an X shape. In some embodiments, the curl of the shear stress provided by the adjacent rod structures to the mass element 320 among the four rod structures may be opposite, and the curl of the shear stress provided by the relative 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 curls of shear stress to the mass element 320, and the third rod structure 313 and the fourth rod structure 314 provide opposite curls of shear stress to the mass element 320; the first rod structure 311 and the fourth rod structure 314 provide the same curl of shear stress to the mass element 320, and the second rod structure 312 and the third rod structure 313 provide the same curl of shear stress to the mass element 320. When the four rod structures are arranged in an X shape, the projections of the four 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, a single rod structure and a symmetry axis (for example, the first symmetry axis 301 or the second symmetry axis 302) may form an angle. For example, an angle may be formed between the fourth rod structure 314 and the first symmetry axis 301. By adjusting the angle The angle of the acoustic output device can control the rolling modes along different symmetric axes when the acoustic output device is vibrating. The rolling may refer to the rotation of the elastic element 300 around the first symmetric axis 301 or the second symmetric axis 302 when the elastic element 300 is vibrating. In some embodiments, in order to minimize the rolling modes when the acoustic output device is vibrating, the angle of The angle range can be 10°-30°. In some embodiments, in order to minimize the rolling mode when the acoustic output device vibrates, the angle The angle range can be 30°-60°. In some embodiments, in order to minimize the rolling mode when the acoustic output device vibrates, the angle The angle range can be 60°-80°.

In some embodiments, the piezoelectric element 330 in the acoustic output device may be an annular structure (as shown in FIG. 3 ), and the multiple rod structures of the elastic element 300 are distributed along the circumference of the annular structure. The mass element 320 and the piezoelectric element 330 are connected through multiple rod structures. It should be noted that when the elastic element is 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 also be other structural types, for example, a piezoelectric beam structure (as shown in FIG. 4 ). For a specific description of the structure of the piezoelectric element 330, please refer to FIG. 9 to FIG. 24 of this specification and related descriptions.

FIG. 4 is an exemplary structural diagram of an elastic element according to some embodiments of the present specification. 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 respectively connected to the mass element 420. In some embodiments, the piezoelectric element 410 of the acoustic output device 400 may include a beam structure, and the mass element 420 may be connected to the middle of the beam structure. For example, the mass element 420 may include a first mass element 421 and a second mass element 422, and the second mass element 422 is connected to the middle of the beam structure. The second elastic element 432 and the first elastic element 431 are respectively connected to the first mass element 421. In some embodiments, a piezoelectric sheet (the surface or the group of surfaces) may be attached to one of the surfaces of the beam structure or a group of opposite surfaces, and the piezoelectric sheet may be stretched and deformed based on an electrical signal, so that the beam structure may generate vibrations perpendicular to the piezoelectric surface based on the electrical signal. In some embodiments, connectors 411 are provided at both ends of the beam structure, and the beam structure is connected to one end of the rod 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 where the second elastic element 432 and the first elastic element 431 are located 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 where the second elastic element 432 and the first elastic element 431 are located 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 where the second elastic element 432 and the first elastic element 431 are located may be parallel to the annular surface of the annular structure.

In some embodiments, the number of rod structures included in the elastic element 430 may be 8, and the 8 rod structures may form a double X shape. Among them, the 4 rod structures in the first elastic element 431 may form a first X shape 401, and the 4 rod structures in the second elastic element 432 may form a second X shape 402, and the first X shape 401 and the second X shape 402 may form a double X shape structure of multiple rod structures. In some embodiments, the double X shape structure formed by multiple rod structures may be a parallel double X shape (as shown in FIG. 4 ), a vertical double X shape (as shown in FIG. 5 ), or other forms of reverse symmetrical distribution. The parallel/vertical double X shape may refer to that the two symmetry axes of the first X shape 401 and the two symmetry axes of the second X shape 402 are respectively parallel/vertical. In some embodiments, any one 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 four rod structures in the first elastic element 431 and/or the second elastic element 432, the curl of the shear stress provided by the adjacent rod structures to the mass element 420 may be opposite, and the curl of the shear stress provided by the opposite rod structures 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 can be arranged in parallel. The central axis of the first elastic element 431 (and/or the second elastic element 432) can be the intersection of the extension lines of the straight lines where the four rod structures are located, and the axis perpendicular to the plane where the first elastic element 431 (and/or the second elastic element 432) is located. In some embodiments, the central axis of the first elastic element 431 (and/or the second elastic element 432) can be parallel to the vibration direction of the mass element 420. In some embodiments, by arranging the central axis of the second elastic element 432 to be parallel to the central axis of the first elastic element 431, the double X-shaped structure formed by the multiple rod structures of the elastic element 430 can be a parallel double X-shaped structure. In some embodiments, the four rod structures in the first elastic element 431 forming the first X-shape 401 can be connected to a piezoelectric element 410 (e.g., a beam structure) through a connector 411, and the four rod structures in the second elastic element 432 forming the second X-shape 402 can be connected to another piezoelectric element 410 (e.g., a beam structure) through a connector 411, and the two piezoelectric elements 410 are arranged parallel to each other in the same plane. The four rod structures forming the first X-shape 401 and the four rod structures forming the second X-shape 402 are also connected to the mass element 420 respectively. In some embodiments, the mass element 420 can be one, or the mass element 420 can also be multiple, and the multiple mass elements 420 can be connected to each other through a rigid connector (not shown in the figure).

FIG. 5 is an exemplary structural diagram of an elastic element according to some embodiments of the present specification. As shown in FIG. 5 , in some embodiments, the second elastic element 432 and the first elastic element 431 may also be coaxially arranged. That is, the central axis of the second elastic element 432 coincides with the central axis of the first elastic element 431. In some embodiments, the projection of the double X-shaped structure formed by the multiple rod structures of the elastic element 430 along the vibration direction may be a double X-shape perpendicular to each other. Two X-shapes perpendicular to each other may mean that the symmetry axes of the two X-shapes are perpendicular to each other. In some embodiments, the second elastic element 432 and the first elastic element 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 be located in different planes perpendicular to the vibration direction. In some embodiments, any one 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 four rod structures in the first elastic element 431 and/or the second elastic element 432, the curl of the shear stress provided by the adjacent rod structures to the mass element 420 may be opposite, and the curl of the shear stress provided by the opposite rod structures to the mass element 420 may be the same.

In some embodiments, the four rod structures forming the first X-shape 401 can be connected to a piezoelectric element (eg, a beam structure) via a connector 411, and the four rod structures forming the second X-shape 402 are connected to another piezoelectric element, and the two piezoelectric elements are arranged perpendicular to each other in the same plane.

In some embodiments, when the shape structure of the elastic element is different, the vibration performance of the acoustic output device may be different. The higher the degree of the reverse symmetry of the elastic element, the fewer the rotational modes generated by the vibration of the elastic element, and the higher the vibration performance of the acoustic output device. FIG. 6 is a frequency curve diagram of the acoustic output device shown in some embodiments of the present specification. As shown in FIG. 6, the horizontal axis represents the resonant frequency of the acoustic output device, the unit is Hz, and the vertical axis represents the acceleration output intensity of the acoustic output device, the unit is 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., the 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., the 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., the elastic element 430 in FIG. 5 ). Combining curves 601, 602, and 603, it can be seen that when the elastic element is in a single X shape, a parallel double X shape, or other types of double X shapes, the frequency response effect of the acoustic output device is better. It should be noted that when the elastic element is a single X-shape, a resonant drum is generated in the curve 601 near 1411 Hz, and the resonant drum is not generated by the rotation mode of the elastic element, but is caused by the mass element connected to the piezoelectric element and the vibration system formed by the piezoelectric element absorbing the vibration of the output end. For example, in conjunction with FIG. 4 , the resonant drum may be caused by the vibration system formed by the second mass element 422 and the piezoelectric beam 410 absorbing the vibration of the first mass element 421.

In some embodiments, the elastic element may also be configured as a double-layer structure, and the double-layer elastic elements are distributed up and down along the vibration direction of the mass element. In some embodiments, the curl of the shear stress provided by the upper elastic element and the lower elastic element to the mass element may be opposite. For example, the curl of the shear stress provided by the multiple bending regions of the upper elastic element is opposite to the curl of the shear stress provided by the multiple bending regions of the lower elastic element. In some embodiments, the curl of the shear stress provided by each layer of the elastic element in the double-layer elastic element to the mass element may be opposite. For example, each layer of elastic element may include at least two parts, and the at least two parts may provide shear stresses with opposite rotations to the mass element. The shear stresses with opposite rotations may offset each other, so that the shear stress provided by each layer of elastic element to the mass element is zero or close to zero.

In some embodiments, the shape of the double-layered elastic element can be any one of a double-layered zigzag shape, a double-layered S-shape, a double-layered spline curve shape, or a double-layered arc shape. For example, the first layer of the double-layered elastic element is a plurality of zigzag rod structures arranged along a first direction, and the second layer is a plurality of zigzag rod structures arranged along a second direction. The first direction and the second direction are opposite to the auxiliary line directions of the rod structure. For another example, each layer of the double-layered elastic element can 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 can have two mutually perpendicular symmetry axes (for example, the double-layered elastic element 300).

In some embodiments, when the structure of the elastic element is a double-layer structure, in the multiple bending regions included in each rod structure in the elastic element on the same layer, the curls of the shear stress provided by the adjacent bending regions may be opposite. In some embodiments, along the vibration direction of the mass element, the curls of the shear stress provided by two rod structures arranged opposite to each other on different layers may also be opposite.

FIG. 7A is an exemplary structural diagram of an elastic element according to some embodiments of the present specification. Referring to FIG. 7A , the elastic element 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 are connected to the mass element 720 and the piezoelectric element 710, respectively. In some embodiments, the first spiral structure 731 and the second spiral structure 732 may be arranged up and down along the vibration direction of the mass element 720. The connection position of the first spiral structure 731 and the piezoelectric element 710 may be a side of the piezoelectric element 710 that is closer to the mass element 720. The connection position 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 helical structure 731 and the second helical structure 732 may be the same, and the helical directions may be opposite. The helical direction may be the direction in which the helical structure rotates around its axis. In some embodiments, at least two elastic elements 730 may rotate in opposite directions along the same axis to form the first helical structure 731 and the second helical structure 732 with opposite helical directions.

In some embodiments, by configuring the elastic element 730 as a double-layer helical structure, the rotation amplitude of the elastic element 730 during the vibration of the acoustic output device 700-1 can be reduced. At the same time, the double-layer helical structure can also increase the elastic coefficient of the elastic element 730, thereby shifting the first resonance peak generated by the resonance of the elastic element 730 and the mass element 720 to the right (i.e., to a high frequency) to meet the vibration performance requirements of the acoustic output device 700-1.

FIG7B is an exemplary structural diagram of an elastic element according to some embodiments of the present specification. The double helical structure of the elastic element 730 shown in FIG7A can also be applied to the acoustic output device 700-2 shown in FIG7B. The structure of the elastic element in FIG7B is substantially the same as that of the elastic element in FIG7A, except that the arrangement of the elastic element is different.

7B , in some embodiments, the elastic element 760 may include a first helical structure 761 and a second helical structure 762, which are arranged up and down along the thickness direction of the mass element 750. The helical directions of the first helical structure 761 and the second helical structure 762 are opposite.

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

In some embodiments, when the elastic element is a spiral structure, the number of layers of the spiral structure is different, and the vibration performance of the corresponding acoustic output device may also be different. In some embodiments, the reverse symmetry of the double-layer spiral structure is higher than the reverse symmetry of the single-layer spiral structure. Therefore, the vibration performance of the acoustic output device whose elastic element is a double-layer spiral structure may be better than the vibration performance of the acoustic output device whose elastic element is a single-layer spiral structure. Figure 7C is an exemplary frequency response curve diagram of the acoustic output device shown in some embodiments of the present specification. Among them, curve 701 can represent the frequency response curve of the acoustic output device whose elastic element is a single-layer spiral structure, and curve 702 can represent the frequency response curve of the acoustic output device whose elastic element is a double-layer spiral structure. By comparing curve 701 and curve 702 , it can be seen that, compared with the case where the elastic element is a single-layer spiral structure, the peak value of the resonance valley formed by the frequency response curve 702 of the acoustic output device when the elastic element is a double-layer spiral structure is significantly improved.

FIG8A is an exemplary structural diagram of an elastic element according to some embodiments of the present specification. Referring to FIG8A , an acoustic output device 800-1 may include a piezoelectric element 810, a mass element 820, and an elastic element 830. The piezoelectric element 810 may include a first piezoelectric element 811 and a second piezoelectric element 812, wherein the second piezoelectric element 812 is 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 curl of the shear stress provided by the inner ring elastic element 832 to the mass element 820 may be opposite to the curl of the shear stress provided by the outer ring elastic element 831 to the mass element 820, so that the elastic element 830 as a whole can provide mutually offsetting shear stresses to the mass element 820. In some embodiments, the inner ring elastic element 832 and the outer ring elastic element 831 may be S-shaped, and the first curl corresponding to the shear stress provided by the S-shaped rod structure of the inner ring elastic element 832 to the mass element 820 is opposite to the second curl corresponding to the 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 element 832 can provide a shear stress of a first rotation to the mass element 820, and the outer ring elastic element 831 can provide a shear stress of a second rotation to the mass element 820. Since the first rotation is opposite to the second rotation, the elastic element 830 as a whole can provide the mass element 820 with shear stresses that offset each other.

In some embodiments, when the rotation of the tangential stress provided by the inner ring elastic element 832 to the mass element 820 is opposite to the rotation of the tangential stress provided by the outer ring elastic element 831 to the mass element 820, during the vibration of the acoustic output device 800-1, the rotational mode generated by the inner ring elastic element 832 and the rotational mode generated by the outer ring elastic element 831 may be opposite, so that the rotational mode generated by the inner ring elastic element 832 and the rotational mode generated by the outer ring elastic element 831 cancel each other (or weaken) to reduce the rotational mode of the acoustic output device 800-1 during the vibration process as a whole.

FIG8B is an exemplary structural diagram of an elastic element according to some embodiments of the present specification. The elastic element shown in FIG8B is substantially the same in structure as the elastic element shown in FIG8A, except for the shape of the elastic element. The shape of the elastic element 830 of the acoustic output device 800-2 is an arc. The first rotation of the shear stress provided by the arc of the inner ring elastic element 832 is opposite to the second rotation of the shear stress provided by the arc of the outer ring elastic element 831.

In some embodiments, when the elastic element includes an inner ring elastic element and an outer ring elastic element, the shape of the inner/outer ring elastic element may not be limited to S-shape and arc shape, but may also be other shapes, such as a broken line shape or a spline curve shape.

For more information about the elastic element including the inner ring elastic element and the outer ring elastic element, please refer to Figures 12 to 18 of this manual and their related descriptions.

FIG9 is an exemplary structural diagram of an acoustic output device according to some embodiments of the present specification. As shown in FIG9 , the acoustic output device 900 may include one or more piezoelectric elements 910, a mass element 920, and one or more elastic elements 930. 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, one or more piezoelectric elements 910 may include a first piezoelectric element 911, and the first piezoelectric element 911 may be a ring-shaped structure. The axial direction of the ring-shaped structure is parallel to the vibration direction of the mass element 920. In some embodiments, one end of the first piezoelectric element 911 along the axial direction is fixed (also referred to as a fixed end), and the mass element 920 is connected to other positions of the first piezoelectric element 911 except this end through the elastic element 930. In the embodiments of the present specification, one end of a piezoelectric element (such as a first piezoelectric element, a second piezoelectric element, etc.) refers to the entire area having a certain thickness (for example, 0.1%, 5% or any thickness in the range of 0.1% to 30% of the total thickness of the annular structure) along the axial direction of the annular structure starting from one of the annular end faces of the annular structure of the piezoelectric element. For example, one end of the first piezoelectric element 911 along the axial direction can be fixed by one of the annular end faces of the first piezoelectric element 911. For another example, one end of the first piezoelectric element 911 along the axial direction can be fixed by the inner side and/or outer side of the annular structure in a certain thickness area near one of the annular end faces of the first piezoelectric element 911. In some embodiments, the elastic element 930 can be connected to another annular end surface opposite to the annular end surface of the fixed end. In some embodiments, the elastic element 930 can also be connected to the inner side surface of the annular structure, and the connection position on the inner side surface 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 between the mass element and the elastic element along the axial direction of the piezoelectric element is located inside the projection of the piezoelectric element along the axial direction. For example, as shown in FIG9 , the projections of the piezoelectric element 910, the elastic element 930, and the mass element 920 along the axial direction of the piezoelectric element 910 are arranged in sequence from the outside to the inside. In some embodiments, when the mass element 920 may be located inside the first piezoelectric element 911, the shape of the mass element 920 may be cylindrical (as shown in FIG9 ), ring-shaped, etc.

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, and the plurality of rod structures are distributed along the circumference of the annular structure. In some embodiments, one end of the elastic element 930 may be connected to any surface of the mass element 920 along the axial direction (for example, a surface close to the piezoelectric element 910). In other embodiments, one end of the elastic element 930 may also be connected to the peripheral surface of the mass element 920. In some embodiments, the other end of the elastic element 930 may be connected to any surface of the non-fixed end on the piezoelectric element 910. For example, in some embodiments, the other end of the elastic element 930 may be connected to the annular end surface of the piezoelectric element 910 close 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 inner surface of the circumference of the piezoelectric element 910. The connection position of the elastic element 930 and 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 elastic element 930 may include at least two parts, and the at least two parts may provide shear stresses with opposite curls to the mass element 920, and the shear stresses with opposite curls may cancel each other out, so that the shear stress provided by the elastic element 930 to the mass element 920 is zero or close to zero. For example, each of the multiple rod structures may include one or more bending regions, and the curls of the shear stresses provided by the adjacent bending regions in the one or more bending regions to the mass element 920 may be opposite, so that the shear stress provided by each rod structure as a whole to the mass element 920 is zero or close to 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 FIGS. 2 to 5 , and the specific contents of the structure of the elastic element may refer to FIGS. 2 to 5 and the related descriptions.

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

FIG10 is a frequency response curve diagram of an acoustic output device according to some embodiments of the present specification. As shown in FIG10 , the horizontal axis represents the resonant frequency of the acoustic output device, the unit is Hz, and the vertical axis represents the acceleration output intensity of the acoustic output device, the unit is dB. In some embodiments, referring to FIG10 , the acoustic output device (e.g., the acoustic output device 900) can form at least two resonant peaks within the audible frequency range (e.g., 20 Hz-20 KHz), wherein the first resonant peak 1010 can be generated by the resonance of the mass element 920 and the elastic element 930, and the second resonant peak 1020 can be generated by the resonance of the piezoelectric element 910. In some embodiments, the frequency f1 of the first resonant peak 1010 of the acoustic output device 900 may be in the range of 50 Hz-9000 Hz. In some embodiments, in order to ensure the low-frequency response of the acoustic output device 900, the frequency f1 of the first resonant peak 1010 of the acoustic output device 900 may be in the range of 50 Hz-500 Hz. In some embodiments, in order to ensure the low-frequency response of the acoustic output device 900, the frequency f1 of the first resonant peak 1010 of the acoustic output device 900 may be in the range of 50 Hz-300 Hz. In some embodiments, the frequency f2 of the second resonant peak 1020 of the acoustic output device 900 may be in the range of 1000 Hz-90000 Hz. In some embodiments, in order to ensure the 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 of 9000 Hz-10000 Hz. In some embodiments, in order to ensure the sound quality of the sound output by the acoustic output device 900 within 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 3000 Hz-7000 Hz. The frequency curve between the first harmonic peak 1010 and the second harmonic peak 1020 can be relatively flat. In the frequency range between the first harmonic frequency f1 and the second harmonic frequency f2 , the acoustic output device 900 has a higher output response capability. When the acoustic output device 900 is applied to an acoustic output device, it can output sound with higher sound quality.

In some embodiments, at least a portion of the mass element may be located outside the piezoelectric element. For example, at least a portion of the mass element may be an annular structure, and the annular structure of the mass element is connected to the piezoelectric element through an elastic element. The projection of the annular structure of the mass element along the axial direction of the annular structure may be located outside the projection of the piezoelectric element along the axial direction. FIG. 11A is an exemplary structural diagram of an acoustic output device shown in some embodiments of the present specification. As shown in FIG. 11A , the mass element 1120 may also be located outside the first piezoelectric element 1111, and the projection of the mass element 1120 along the axial direction of the first piezoelectric element 1111 is located outside the projection of the first piezoelectric element 1111 along the axial direction, and the mass element 1120 and the first piezoelectric element 1111 are connected via the elastic element 1130. The projection of the first piezoelectric element 1111, the elastic element 1130, and the mass element 1120 along the axial direction of the first piezoelectric element 1111 are arranged in sequence from the inside to the outside. In some embodiments, when the mass element 1120 is located outside the first piezoelectric element 1111, the shape of the mass element 1120 may be a ring.

In some embodiments, when the mass element 1120 is located outside the first piezoelectric element 1111, a cover plate 1121 may be provided on a side of the mass element 1120 that is away from the first piezoelectric element 1111 along the axis direction of the first piezoelectric element 1111. The cover plate 1121 may seal the side of the mass element 1120 that is away from the first piezoelectric element 1111 along the axis direction of the first piezoelectric element 1111. For example, the cover plate 1121 may be a circular structure, and the periphery of the cover plate 1121 is aligned and tightly connected with the side of the mass element 1120 that is away from the first piezoelectric element 1111 along the axis direction of the first piezoelectric element 1111. By arranging a cover plate 1121 on a side of the mass element 1120 away from the first piezoelectric element 1111 along the axial direction of the first piezoelectric element 1111, the cover plate 1121 can be used as a vibration plate to transmit vibration signals. The cover plate 1121 can also be used to connect the mass element 1120 to other structures of the acoustic output device 1100, such as a diaphragm.

FIG11B is a frequency response curve diagram of an acoustic output device according to some embodiments of the present specification. When the mass element 1120 is located outside the first piezoelectric element 1111, the frequency response curve diagram of the acoustic output device 1100 may be as shown in FIG11B. In some embodiments, the frequency f1 (also referred to as the first harmonic frequency) of the first harmonic peak 1101 of the acoustic output device 1100 may be in the range of 50 Hz-11000 Hz. In some embodiments, in order to ensure the low-frequency response of the acoustic output device 1100, the frequency f1 of the first harmonic peak 1101 of the acoustic output device 1100 may be in the range of 50 Hz-500 Hz. In some embodiments, in order to ensure the 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 50 Hz-300 Hz. 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 may be in the range of 1000 Hz-50000 Hz. In some embodiments, in order to ensure the 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 1000 Hz-10000 Hz. In some embodiments, in order to ensure the 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 4000 Hz-8000 Hz.

FIG12 is an exemplary structural diagram of an acoustic output device according to some embodiments of the present specification. Referring to FIG12 , the acoustic output device 1200 may include one or more piezoelectric elements 1210, a mass element 1220, and one or more elastic elements 1230. 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, one or more piezoelectric elements 1210 may include a first piezoelectric element 1211 and a second piezoelectric element 1212, wherein the first piezoelectric element 1211 includes a first annular structure, and the second piezoelectric element 1212 includes a second annular structure; the second piezoelectric element 1212 is disposed inside the first annular structure. In some embodiments, one end of the first piezoelectric element 1211 along the axial direction (e.g., the end away from the mass element 1220) may be fixed, and the second piezoelectric element 1212 is connected to other positions 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 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 between 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 ring structure along the axial direction.

In some embodiments, the elastic element 1230 may include an outer ring elastic element 1231 and an inner ring elastic element 1232. The outer ring elastic element 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 through the outer ring elastic element 1231. The inner ring elastic element 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 through the inner ring elastic element 1232.

In some embodiments, the shear stress curl provided by the inner ring elastic element 1232 and the outer ring elastic element 1231 to the mass element 1220 is opposite. In some embodiments, the shear stress curl provided by the multiple rod structures in the inner ring elastic element 1232 and the multiple rod structures in the outer ring elastic element 1231 to the mass element 1220 can be respectively opposite. For example, the inner ring elastic element 1232 can provide a shear stress of a first curl to the mass element 1220, and the outer ring elastic element 1231 can provide a shear stress of a second curl to the mass element 1220. In some embodiments, as shown in FIG. 12 , the inner ring elastic element 1232 and the outer ring elastic element 1231 can include a plurality of rod structures, each of which includes one or more bending regions. By setting the bending directions of the rod structures in the inner ring elastic element 1232 and the outer ring elastic element 1231 to be opposite, the first curl can be opposite to the second curl, so that the inner ring elastic element 1232 and the outer ring elastic element 1231 provide shear stress with opposite curls to the mass element 1220. In some embodiments, the shapes of the inner ring elastic element 1232 and the outer ring elastic element 1231 may not be limited to the S shape as shown in FIG. 12, but may also be other shapes, such as a broken line shape, a spline curve shape, an arc shape, and a straight line shape. In some embodiments, the inner ring elastic element 1232 and the outer ring elastic element 1231 may also include a spiral structure. By setting the spiral directions of the spiral structures in the inner ring elastic element 1232 and the outer ring elastic element 1231 to be opposite, the first curl can be opposite to the second curl, so that the inner ring elastic element 1232 and the outer ring elastic element 1231 provide shear stresses with opposite curls to the mass element 1220. Thus, the shear stresses provided by the inner ring elastic element 1232 and the outer ring elastic element 1231 to the mass element 1220 can offset each other, so that the shear stress provided by the elastic element 1230 to the mass element 1220 is zero or close to zero, thereby preventing or reducing the rotation of the mass element 1220.

In some embodiments, by providing the second piezoelectric element 1212 in the acoustic output device 1200, 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) can constitute an overall mass. When the overall mass resonates with the elastic element connecting the overall mass and the first piezoelectric element 1211, the overall mass is greater than the mass of the mass element, thereby The first resonance peak of the acoustic output device 1200 is moved to a low frequency, and when the acoustic output device 1200 vibrates, the double ring structure composed of the first ring structure and the second ring structure can also generate a third resonance peak between the first resonance peak and the second resonance peak through resonance, which can be shown as an additional resonance peak between the first resonance peak and the second resonance peak in the frequency curve of the acoustic output device 1200, i.e., the third resonance peak. In some embodiments, the third resonance frequency corresponding to the third resonance peak can be 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 resonant peak of the acoustic output device 1200 with a dual ring structure may be 50 Hz-2000 Hz. In some embodiments, in order to ensure the low-frequency response of the acoustic output device 1200, the frequency range of the first resonant peak of the acoustic output device 1200 with a dual ring structure may be 50 Hz-1000 Hz. In some embodiments, in order to ensure the low-frequency response of the acoustic output device 1200, the frequency range of the first resonant peak of the acoustic output device 1200 with a dual ring structure may be 50 Hz-500 Hz. In some embodiments, in order to ensure the low-frequency response of the acoustic output device 1200, the frequency range of the first resonance peak of the acoustic output device 1200 with a double-ring structure may be 50 Hz-100 Hz.

FIG13 is a frequency response curve diagram of an acoustic output device according to some embodiments of the present specification. Curve 1310 may represent the frequency response curve of an acoustic output device (e.g., acoustic output device 900) provided with only the first piezoelectric element, and curves 1320, 1330, 1340, and 1350 represent the frequency response curves of an acoustic output device (e.g., acoustic output device 1200) provided with the first piezoelectric element and the second piezoelectric element, and when the electrical signals received by the first piezoelectric element and the second piezoelectric element have different phase differences. By comparing the curve 1310 and the curves 1320-1350, it can be seen that when the acoustic output device is additionally provided with a second piezoelectric element, the frequency response curve 1320 of the acoustic output device can form not only the first resonance peak 1301 and the second resonance peak 1302, but also an additional resonance peak, namely, the third resonance peak 1303.

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 the first piezoelectric element. FIG. 14 is an exemplary structural diagram of an acoustic output device according to some embodiments of the present specification. 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 includes a first annular structure, and the second piezoelectric element 1412 includes 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 along the axial direction of the annular structure can be fixed, and the first piezoelectric element 1411 is connected to a position other than the fixed end of the second piezoelectric element 1412 through at least one of the one or more elastic elements 1430 (for example, the inner annular elastic element 1432); at least a portion of the mass element 1420 can be an annular structure, and the annular structure of the mass element 1420 is connected to the first annular structure through the outer annular elastic element 1431 in the elastic element 1430, and the projection of the annular structure of the mass element 1420 along the axial direction can be located outside the projection of the first annular structure along 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 include a plurality of rod structures, each of which includes one or more bending regions. In some embodiments, the shapes of the inner ring elastic element 1432 and the outer ring elastic element 1431 may not be limited to the S-shape shown in FIG. 14 , but may also be other shapes, such as a broken line shape, a spline curve shape, an arc shape, and a straight line shape. In some embodiments, the inner ring elastic element 1432 and the outer ring elastic element 1431 may also include a spiral 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 setting the structures of the inner ring elastic element 1432 and the outer ring elastic element 1431 (for example, the bending directions of the rod structure are opposite, the spiral directions of the spiral structure are opposite, etc.), the first curl can be opposite to the second curl, so that the inner ring elastic element 1432 and the outer ring elastic element 1431 provide shear stresses with opposite curls to the mass element 1420. Therefore, the shear stress provided by the elastic element 1430 to the mass element 1420 can be zero or close to zero, thereby preventing or reducing the 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 cover plate may be provided on a side of the mass element 1420 that is away from the first piezoelectric element 1411 along the axial direction of the first piezoelectric element 1411. In some embodiments, a closed side of the mass element 1420 (i.e., a side of the mass element 1420 that is provided with a cover plate) may extend in a direction away from an unclosed side, and a projection of the closed surface of the mass element 1420 along the axial direction may be in a variety of shapes, such as a circle, a square, etc. The unsealed end of the mass element 1420 is connected to the piezoelectric element 1410 (eg, the first piezoelectric element 1411 ), and the projection of the end surface of the unsealed end of the mass element 1420 along the axial direction is a ring.

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) can constitute an overall mass. When the overall mass resonates with the elastic element connecting the overall mass and the second piezoelectric element 1412, the first resonance peak of the acoustic output device 1400 can be moved to a low frequency, and the dual-ring structure resonance of the acoustic output device 1400 can also generate a third resonance peak between the first resonance peak and the second resonance peak.

FIG15 is a frequency response curve diagram of an acoustic output device according to some embodiments of the present specification. Curve 1510 may represent the frequency response curve of an acoustic output device (e.g., acoustic output device 900) provided with only the first piezoelectric element, and curves 1520, 1530, 1540, and 1550 represent the frequency response curves of an acoustic output device (e.g., acoustic output device 1400) provided with the first piezoelectric element and the second piezoelectric element, and when the electrical signals received by the first piezoelectric element and the second piezoelectric element have different phase differences. By comparing the curve 1510 and the curves 1520-1550, it can be seen that when the acoustic output device is additionally provided with a second piezoelectric element, not only the first resonant peak 1501 and 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 structural diagram of an acoustic output device according to some embodiments of the present specification. As shown in FIG. 16 , in some embodiments, at least a portion of the mass element 1620 may be an annular structure, and the annular structure of the mass element 1620 may be located between the first annular structure of the first piezoelectric element 1611 and the second annular structure of the second piezoelectric element 1612. The projection of the annular structure of the mass element 1620 along the axial direction may be located between the projection of the first annular structure and the projection of the second annular structure along the axial direction. The annular structure of the mass element 1620 is connected to the first piezoelectric element 1611 through at least one of the one or more elastic elements 1630 (for example, the outer ring elastic element 1631), and the mass element 1620 is connected to the second piezoelectric element 1612 through at least another one of the one or more elastic elements (for example, the inner ring elastic element 1632). In some embodiments, the shape of the elastic element 1630 (for example, the outer ring elastic element 1631 and/or the inner ring elastic element 1632) can be S-shaped, and the bending directions of adjacent S-shaped elastic elements 1630 can be opposite, so that the adjacent S-shaped elastic elements 1630 can provide shear stress with opposite rotation to the mass element 1620, thereby avoiding the mass element 1620 from generating a rotational tendency around the axial direction, and further avoiding the acoustic output device 1600 from generating a rotational mode. In some embodiments, the projection of the elastic element 1630 along the vibration direction (i.e., 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 ), so that the curl corresponding to the tangential stress provided by the S-shape symmetrical along the symmetry axis is different (e.g., opposite), so that the S-shaped elastic elements 1630 on both sides of the symmetry axis can provide the mass element 1620 with tangential stress with opposite curl, thereby preventing the mass element 1620 from generating a rotational tendency around the axial direction, and further preventing the acoustic output device 1600 from generating a rotational mode. In some embodiments, referring to FIG. 16 , the connection positions of adjacent S-shaped elastic elements 1630 on the mass element 1620 or the piezoelectric element 1610 (e.g., the first piezoelectric element 1611 and/or the second piezoelectric element 1612) may be the same. In other embodiments, the connection positions of adjacent S-shaped elastic elements 1630 on the mass element 1620 or the piezoelectric element 1610 (e.g., the first piezoelectric element 1611 and/or the second piezoelectric element 1612) may also be different. In some embodiments, the shapes of the inner ring elastic element 1632 and the outer ring elastic element 1631 may not be limited to the S shape as shown in FIG. 16 , but may also be other shapes, such as a broken line shape, a spline curve shape, an arc shape, and a straight line shape. In some embodiments, the inner ring elastic element 1632 and the outer ring elastic element 1631 may further include a spiral structure. By setting the structures of the inner ring elastic element 1632 and the outer ring elastic element 1631 (for example, the bending directions of the rod structure are opposite, the spiral directions of the spiral structure are opposite, etc.), the inner ring elastic element 1632 and the outer ring elastic element 1631 can provide shear stress with opposite rotation to the mass element 1620. Thereby, the shear stress provided by the elastic element 1630 to the mass element 1620 can be zero or close to zero, thereby preventing or reducing the 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 along the axial direction. In some embodiments, when one end of the first piezoelectric element 1611 is fixed along the axial direction, the two end surfaces of the second piezoelectric element 1612 along the axial direction are freely arranged, and the second piezoelectric element 1612 can be used as a piezoelectric free ring, and the first piezoelectric element 1611 can be used as a piezoelectric fixed ring. Or when one end of the second piezoelectric element 1612 is fixed along the axial direction, the two end surfaces of the first piezoelectric element 1611 along the axial direction are freely arranged, and the first piezoelectric element 1611 can be used as a piezoelectric free ring, and the second piezoelectric element 1612 can be used as a piezoelectric fixed ring. In some embodiments, when different piezoelectric elements in at least one piezoelectric element 1610 have fixed ends along an axial direction, the acoustic output device 1600 may have different frequency response curves. The overall mass formed by the piezoelectric free ring and the mass element 1620 (and the elastic element connecting the piezoelectric free ring and the mass element 1620) can resonate with the elastic element connecting the overall mass and the piezoelectric fixed ring, so that the first resonance peak can be moved to a low 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), so that when the acoustic output device 1600 vibrates, the piezoelectric free ring and the piezoelectric fixed ring resonance can form a third resonance peak in the frequency curve. The third harmonic frequency corresponding to the third harmonic peak may be between the first harmonic frequency corresponding to the first harmonic peak and the second harmonic frequency corresponding to the second harmonic peak. In some embodiments, the frequency range of the first harmonic peak of the acoustic output device 1600 may be similar to the frequency range of the first harmonic peak of the acoustic output device 1200, which will not be described in detail herein.

FIG. 17 is a frequency response curve diagram of an acoustic output device according to some embodiments of the present specification. The frequency response curves except curve 1710 in FIG. 17 may be frequency response curves of an acoustic output device (e.g., acoustic output device 1600) in which a first piezoelectric element (e.g., first piezoelectric element 1611) has a fixed end along an axial direction. Referring to FIG. 17 , curve 1710 may represent a frequency response curve of an acoustic output device (e.g., acoustic output device 900) in which only the first piezoelectric element is provided, and curves 1720, 1730, and 1740 represent frequency response curves of an acoustic output device in which a first piezoelectric element and a second piezoelectric element are provided, and the electrical signals received by the first piezoelectric element and the second piezoelectric element have different phase differences. By comparing the curve 1710 and the curves 1720-1740, it can be seen that when the acoustic output device is provided with the first piezoelectric element and the second piezoelectric element, a third resonant peak 1703 in addition to the first resonant peak 1701 and the second resonant peak 1702 can also be formed in the frequency response curve 1720 of the acoustic output device.

FIG. 18 is a frequency response curve diagram of an acoustic output device according to some embodiments of the present specification. In FIG. 18 , the frequency response curves except curve 1810 may be frequency response curves of an acoustic output device in which the second piezoelectric element (e.g., the second piezoelectric element 1612) has a fixed end along the axial direction. Curve 1810 may represent the frequency response curve of an acoustic output device (e.g., the vibration device 900) in which only the first piezoelectric element is provided, and curves 1820, 1830, and 1840 represent the frequency response curves of an acoustic output device (e.g., the acoustic output device 1600) in which the first piezoelectric element and the second piezoelectric element are provided, and the electrical signals received by the first piezoelectric element and the second piezoelectric element have different phase differences. By comparing the curve 1810 and the curves 1820-1840, it can be seen that when the acoustic output device is provided with the first piezoelectric element and the second piezoelectric element, a third resonant peak 1803 in addition to the first resonant peak 1801 and the second resonant peak 1802 can also be formed in the frequency response curve 1820 of the acoustic output device.

FIG19 is an exemplary structural diagram of an acoustic output device according to some embodiments of the present specification. Referring to FIG19 , the 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, the one or more piezoelectric elements 1910 may include two first piezoelectric elements 1911, and the two first piezoelectric elements 1911 may be arranged vertically along the axial direction and connected to each other. The two first piezoelectric elements 1911 are arranged vertically along the axial direction to form a double-layer single-ring structure of the piezoelectric element 1910.

In some embodiments, the mass element 1920 can be connected to the two first piezoelectric elements 1911 through one or more elastic elements 1930. In some embodiments, the one or more elastic elements 1930 can be provided in double layers, and the double-layer elastic element 1930 includes two layers of first elastic elements 1931, and the two layers of first elastic elements 1931 are arranged up and down along the axis direction of the piezoelectric element 1910. In some embodiments, the two layers of first elastic elements 1931 can be connected to the circumference of the two first piezoelectric elements 1911. The mass element 1920 is connected to the two piezoelectric elements 1911 through the two layers of first elastic elements 1931. In some embodiments, the two layers of first elastic elements 1931 can provide shear stress with opposite rotation to the mass element 1920. In some embodiments, the two layers of first elastic elements 1931 can include multiple rod structures respectively, and the bending directions of the multiple rod structures of the first layer and the bending directions of the multiple rod structures of the second layer can be set oppositely, so that the first rotation of the shear stress provided by the first layer of elastic elements to the mass element 1920 is opposite to the second rotation of the shear stress provided by the second layer of elastic elements to the mass element 1920, so that the shear stress provided by the two layers of first elastic elements 1931 to the mass element 1920 is zero or close to zero, thereby preventing or reducing the rotation of the mass element 1920. In some embodiments, the two-layer first elastic element 1931 may also include a first spiral structure and a second spiral structure, the first spiral structure and the second spiral structure have the same axis and opposite spiral directions, so that the first spiral structure and the second spiral structure can provide shear stress with opposite rotation to the mass element 1920.

In some embodiments, when there are two first piezoelectric elements 1911, the displacement changes of the two first piezoelectric elements 1911 along the axial direction during the vibration process may be opposite. That is, the displacement of one of the two first piezoelectric elements 1911 along the axial direction during the vibration process becomes larger (i.e., elongated), and the displacement of the other of the two first piezoelectric elements 1911 along the axial direction during the vibration process becomes smaller (i.e., contracted). In some embodiments, the displacement change of the first piezoelectric element 1911 along the axial direction during the vibration process can be regulated by the polarization direction of the first piezoelectric element 1911 and the electrode polarity of the electrical signal. For details, please refer to the relevant description of Figures 20A and 20B of this specification.

In some embodiments, the piezoelectric element 1910 may include a plurality of first piezoelectric elements 1911, for example, 4, 6, 8, etc. The plurality of first piezoelectric elements 1911 may be connected in sequence along 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 (for example, divided into multiple layers). The elastic elements of adjacent layers in the multi-layer elastic element may provide the mass element 1920 with a shear stress with an opposite rotation. In some embodiments, the number of mass elements 1920 may also be multiple, and each of the plurality of mass elements 1920 may be connected to one first piezoelectric element 1911 through a plurality of elastic elements 1930.

FIG. 20A is an exemplary circuit diagram of a first piezoelectric element according to some embodiments of the present specification. Referring to FIG. 20A , the polarity of the connection surface of the two first piezoelectric elements 1911 may be the same, and the electrode polarity of the electrical signal of the connection surface may be the same. For the convenience of description, the two first piezoelectric elements 1911 may be respectively recorded as an upper piezoelectric element 19111 and a lower piezoelectric element 19112. 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 connection surface 2010, and the lower piezoelectric element 19112 may have a lower connection surface 2020. In some embodiments, when the polarization direction of the upper piezoelectric element 19111 is the same as the polarization direction of the lower piezoelectric element 19112 (as shown by the arrow in FIG. 20A ), the electrode polarity (e.g., positive or negative) of the upper connection surface 2010 connected to the electrical signal can be the same as the electrode polarity of the lower connection surface 2020 connected to the electrical signal. In this configuration, the potential direction inside the upper piezoelectric element 19111 can be opposite to the potential direction inside the lower piezoelectric element 19112.

By setting the polarization directions of the upper piezoelectric element 19111 and the lower piezoelectric element 19112 to be the same, when the upper piezoelectric element 19111 and the lower piezoelectric element 19112 are connected to electric potentials (or electric signals) in opposite directions, the upper piezoelectric element 19111 and the lower piezoelectric element 19112 can generate displacements in opposite directions.

FIG. 20B is another exemplary circuit diagram of the first piezoelectric element according to some embodiments of the present specification. Referring to FIG. 20B , the polarities of the connection surfaces of the two first piezoelectric elements may be opposite, and the electrode polarities of the electrical signals of the connection surfaces may be opposite. In some embodiments, when the upper piezoelectric element 19113 is connected to the lower piezoelectric element 19114, the upper piezoelectric element 19113 may have an upper connection surface 2030, and the lower piezoelectric element 19114 may have a lower connection surface 2040. 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 electrode polarity (e.g., positive or negative) of the upper connection surface 2030 connected to the electrical signal can be opposite to the electrode polarity of the lower connection surface 2040 connected to the electrical signal. In this configuration, the potential direction inside the upper piezoelectric element 19111 can be the same as the potential direction inside the lower piezoelectric element 19112.

By setting the polarization directions of the upper piezoelectric element 19113 and the lower piezoelectric element 19114 to be opposite, when the upper piezoelectric element 19113 and the lower piezoelectric element 19114 are connected to the same direction of electric potential (or electric signal), the upper piezoelectric element 19113 and the lower piezoelectric element 19114 can generate displacements in opposite directions.

FIG21 is an exemplary structural diagram of an acoustic output device according to some embodiments of the present specification. The structure of the acoustic output device 2100 shown in FIG21 is similar to the structure of the acoustic output device 1200 shown in FIG12 , except that the structure of the piezoelectric element is different. The piezoelectric element 1210 of the acoustic output device 1200 is a single-layer double-ring structure, and the piezoelectric element 2110 of the acoustic output device 2100 is 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 are arranged vertically along the axis direction and connected to each other, and the two second piezoelectric elements 2112 are located inside the first annular structure and are arranged vertically along the axis direction and connected to each other. The axes of the two second piezoelectric elements 2112 may coincide with the axes of the two first piezoelectric elements 2111, and the projections of the two second piezoelectric elements 2112 along the axis direction are located inside the projections of the first annular structure of the two first piezoelectric elements 2111 along the axis 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 elastic element may include an outer ring elastic element 2132, and the outer ring elastic element 2132 is located between the first ring structure and the second ring 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 through 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 through 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 the 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 respectively through at least one of the one or more elastic elements 2130. For example, the elastic element 2130 may include an inner annular elastic element 2131, which is located between the second annular structure and at least a portion of the mass element 2120. The projection of the connection point between the mass element 2120 and the inner annular elastic element 2131 along the axial direction is located within the projection of the second annular structure along the axial direction. The inner ring elastic element 2131 may include two elastic elements arranged along the axial direction, and the mass element 2120 is connected to the two second piezoelectric elements 2112 respectively through the two elastic elements in the inner ring elastic element 2131. 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 through one inner ring elastic element 2131.

In some embodiments, the shapes 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 zigzag shape, a spline curve shape, an arc shape, a straight line shape, etc. In some embodiments, the inner ring elastic element 2131 and the outer ring elastic element 2132 may also include a spiral structure. In some embodiments, the setting manner between the rotation of the shear stress provided by the inner ring elastic element 2131 to the mass element 2120 and the rotation of the shear stress provided by the outer ring elastic element 2132 to the mass element 2120, as well as the setting manner of the shear stress rotation provided by the two elastic elements in the inner ring elastic element 2131 and/or the outer ring elastic element 2132 to the mass element 2120 can be referred to other places in this specification and will not be repeated here.

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 along the axial direction may be fixed, and the other end may be connected to the second piezoelectric element 2112 through the outer ring elastic element 2132. For example, the outer ring elastic element 2132 may also include two elastic elements arranged along the axial direction, and the two first piezoelectric elements 2111 are respectively connected to the two second piezoelectric elements 2112 through the two elastic elements in the outer ring elastic element 2132. In this case, the second piezoelectric element 2112 may be used as a piezoelectric free ring, and the first piezoelectric element 2111 may be used as a piezoelectric fixed ring.

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

In some embodiments, when the mass element 2120 is located outside the first piezoelectric element 2111, one end of the second piezoelectric element 2112 along the axial direction can 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 can be used as a piezoelectric fixed ring, and the first piezoelectric element 2111 can be used 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 the two first piezoelectric elements 2111 and the two second piezoelectric elements 2112 respectively through one or more elastic elements 2130. For example, the mass element 2120 may be connected to the two first piezoelectric elements 2111 respectively through the outer annular elastic element 2132, and the mass element 2120 may be connected to the two second piezoelectric elements 2112 respectively through the inner annular elastic element 2131.

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 along the axial direction. In this case, one of the first piezoelectric element 2111 and the second piezoelectric element 2112 can be used as a piezoelectric free ring, and the other can be used as a piezoelectric fixed ring.

It should be noted that when the piezoelectric element 2110 has a double-layer structure, the piezoelectric element 2110 may not have a fixed end along the axial direction, so that the vibration device 2100 can be more user-friendly in a bone conduction headset where it is difficult to find a strict fixed boundary.

It should be noted that when the piezoelectric element 2110 is a double-layer structure, the elastic element can also be a double-layer structure, and the curl of the shear stress provided by the two layers of elastic elements in the double-layer structure of the elastic element can be opposite. In some embodiments, the piezoelectric element can also be a multi-layer multi-ring structure, for example, a 4-layer 4-ring structure. The piezoelectric element with a multi-layer multi-ring structure is similar to the piezoelectric element with a double-layer double-ring structure, and will not be repeated here.

FIG22 is a frequency response curve diagram of an acoustic output device according to some embodiments of the present specification. Curve 2210 may represent the frequency response curve of the acoustic output device when the piezoelectric element is a single-layer single-ring structure, and curve 2220 represents the frequency response curve of the acoustic output device when the piezoelectric element is a single-layer double-ring structure and the first piezoelectric element has a fixed end along the axial direction. In some embodiments, by providing a piezoelectric free ring in the acoustic output device, a third resonance peak in addition to the first resonance peak and the second resonance peak may be formed in the frequency response curve of the acoustic output device. For example, comparing curve 2210 and curve 2220, curve 2220 may form a third resonant peak in addition to the first resonant peak and the second resonant peak, and the frequency of the third resonant peak is between the frequency of the first resonant peak and the frequency of the second resonant peak.

Continuing to refer to FIG22 , curve 2230 represents the frequency response curve of the acoustic output device in which the piezoelectric element is a double-layer double-ring structure and the first piezoelectric element has a fixed end along the axial direction, and curve 2240 represents the frequency response curve of the acoustic output device in which the piezoelectric element is a double-layer double-ring structure and the piezoelectric element does not have a fixed end along the axial direction. In some embodiments, by providing a piezoelectric element with a double-layer reverse vibration structure, the sensitivity of the acoustic output device in the audible frequency range can be improved. For example, comparing curve 2220 with curve 2230, curve 2230 is shifted upward as a whole compared to curve 2220, and the sensitivity of curve 2230 is higher than that of curve 2220. In some embodiments, by setting the first piezoelectric element and the second piezoelectric element to be in a free ring state, the first piezoelectric element and the second piezoelectric element (and the elastic element used for connection) together with the mass element constitute an overall mass, so that the low-frequency resonant peak of the acoustic output device is shifted to the right. For example, comparing curve 2230 with curve 2240, the first resonant peak of curve 2240 is shifted to the right relative to the first resonant peak of curve 2230, and the amplitude of the first resonant peak of curve 2240 and the amplitude of the frequency band before the first resonant peak are increased, thereby improving the low-frequency performance.

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

FIG23 is an exemplary structural diagram of an acoustic output device according to some embodiments of the present specification. As shown in FIG23 , 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, one or more piezoelectric elements 2310 may include a piezoelectric beam (or beam structure) 2340. The piezoelectric beam 2340 may include a substrate 2343 and a piezoelectric sheet (e.g., a piezoelectric sheet 2341 and a piezoelectric sheet 2342). In some embodiments, the piezoelectric beam 2340 may be connected to the mass element 2320. In some embodiments, the piezoelectric beam 2340 may be located on a side of the mass element 2320 away from the piezoelectric element 2310 along the axial direction of the annular structure of the piezoelectric element 2310 and connected to the mass element 2320. In some embodiments, the piezoelectric beam 2340 may be a plate-shaped structure, and the plate surface (i.e., the surface with the largest area) of the plate-shaped structure is arranged parallel to the annular end surface of the annular structure of the piezoelectric element 2310.

In some embodiments, the piezoelectric sheet 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 respectively disposed on both sides of the piezoelectric beam 2340 along the axial direction of the ring structure of the piezoelectric element 2310. For example, the first piezoelectric sheet 2341 may be disposed on a side of the piezoelectric beam 2340 that is far from the piezoelectric element 2310 along the axial direction, and the second piezoelectric sheet 2342 may be disposed on a side of the piezoelectric beam 2340 that is close to the piezoelectric element 2310 along the axial direction.

In some embodiments, the first piezoelectric sheet 2341 and/or the second piezoelectric sheet 2342 can be used to generate deformation based on an electrical signal, and the direction of the deformation (also called the displacement output direction) is perpendicular to the 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 can generate mechanical vibration by warping along the electrical direction of the piezoelectric sheet based on the deformation of the piezoelectric sheet. 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 piezoelectric sheet 2341 and the second piezoelectric sheet 2342 may be arranged opposite to each other along the axial direction of the ring structure. That is, in the axial direction of the ring 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 piezoelectric sheet 2341 and the second piezoelectric sheet 2342 may be perpendicular to their respective electrical directions. In some embodiments, the electrical direction of the first piezoelectric sheet 2341 is set opposite to the electrical direction of the second piezoelectric sheet 2342, and when the first piezoelectric sheet 2341 and the second piezoelectric sheet 2342 are simultaneously connected to a voltage signal of the same direction, the first piezoelectric sheet 2341 and the second piezoelectric sheet 2342 can generate displacements in opposite directions, thereby vibrating the piezoelectric beam 2340. The vibration direction of the piezoelectric beam 2340 is perpendicular to the displacement output direction of the first piezoelectric sheet 2341 and the second piezoelectric sheet 2342. For example, the first piezoelectric sheet 2341 can shrink along the axis direction perpendicular to the ring structure, and the second piezoelectric sheet 2342 can stretch along the axis direction perpendicular to the ring structure, so that the piezoelectric beam 2340 generates vibration along the axis direction of the ring structure. In some embodiments, the piezoelectric beam 2340 can be connected to the mass element 2320 and output vibration through the mass element 2320. In some embodiments, the piezoelectric beam 2340 can be directly connected to the mass element 2320, so that the resonance peak of the acoustic output device 2300 includes a high-frequency resonance peak (for example, a frequency range of 2 kHz-20 kHz) generated by the resonance of the piezoelectric beam 2340, that is, the piezoelectric beam 2340 constitutes a high-frequency unit of the acoustic output device 2300.

In some embodiments, the piezoelectric element 210 of the annular structure may also include a piezoelectric sheet, which is in a block shape (e.g., an annular block shape). The piezoelectric sheet may generate mechanical vibration based on an electrical signal, and the direction of the mechanical vibration of the piezoelectric sheet is parallel to the electrical direction of the piezoelectric sheet. In some embodiments, when the piezoelectric sheet is connected to a voltage signal along the axial direction of the annular structure, the piezoelectric sheet may vibrate along the axial direction of the annular structure, thereby generating a displacement output along the axial direction of the annular structure.

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

FIG24 is an exemplary structural diagram of an acoustic output device according to some embodiments of the present specification. The structure of the acoustic output device 2400 in FIG24 is substantially the same as the structure of the acoustic output device 2300 in FIG23 , except for the structure and number of mass elements, and the connection method between the mass element and the piezoelectric beam.

Referring to FIG. 24 , in some embodiments, the mass element may include a first mass element 2421 and a second mass element 2422. The first mass element 2421 may be connected to the middle of the piezoelectric beam 2340 through 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 through the elastic element 2330, and the piezoelectric element 2310 includes an annular structure, and the vibration direction of the piezoelectric element 2310 is parallel to the axial direction of the annular structure. In some embodiments, the two ends of the piezoelectric beam 2340 may be connected to the second mass element 2422 respectively. The vibration of the acoustic output device 2400 may be output through the second mass element 2422 at the end of the piezoelectric beam 2340. In some embodiments, the vibration of the acoustic output device 2400 can also be output through the first mass element 2421. In some embodiments, the first mass element 2421 in the acoustic output device 2400 can constitute a low-frequency unit of the acoustic output device 2400 through the connection portion of one or more elastic elements 2330 and the piezoelectric beam 2340, and the piezoelectric element 2310 with a ring structure can constitute a high-frequency unit of the acoustic output device 2400.

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

The basic concepts have been described above. Obviously, for those with ordinary knowledge in the art, the above detailed disclosure is only for example and does not constitute a limitation of the present invention. Although not explicitly stated here, those with ordinary knowledge in the art may make various modifications, improvements and amendments to the present invention. Such modifications, improvements and amendments are suggested in the present invention, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present invention.

At the same time, the present invention uses specific words to describe the embodiments of the present invention. For example, "one embodiment", "an embodiment", and/or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present invention. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different places in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of the present invention can be appropriately combined.

Finally, it should be understood that the embodiments described in the present invention are only intended to illustrate the principles of the embodiments of the present invention. Other variations may also fall within the scope of the present invention. Therefore, as an example and not a limitation, alternative configurations of the embodiments of the present invention may be considered consistent with the teachings of the present invention. Accordingly, the embodiments of the present invention are not limited to the embodiments explicitly introduced and described herein.

100: Acoustic output device 110: Piezoelectric element 120: Mass element 130: Elastic element 200: Elastic element 201: Dashed line 202: Symmetric axis 203: Mass element 210: Rod structure 211: First bending region 212: Second bending region 300: Elastic element 301: First symmetric axis 302: Second symmetric axis 311: First rod structure 312: Second rod structure 313: Third rod structure 314: Fourth rod structure 320: Mass element 330: Piezoelectric element 400: Acoustic output device 401: First X-shape 402: Second X-shape 410: piezoelectric element 411: connector 420: mass element 421: first mass element 422: second mass element 430: elastic element 431: first elastic element 432: second elastic element 601: curve 602: curve 603: curve 700-1: acoustic output device 700-2: acoustic output device 701: curve 702: curve 710: piezoelectric element 711: connector 720: mass element 730: elastic element 731: first spiral structure 732: second spiral structure 750: mass element 760: elastic element 761: first spiral structure 762: Second spiral structure 800-1: Acoustic output device 800-2: Acoustic output device 810: Piezoelectric element 811: First piezoelectric element 812: Second piezoelectric element 820: Mass element 830: Elastic element 831: Outer ring elastic element 832: Inner ring elastic element 900: Acoustic output device 910: Piezoelectric element 911: First piezoelectric element 920: Mass element 930: Elastic element 1010: First resonance peak 1020: Second resonance peak 1100: Acoustic output device 1101: First resonance peak 1102: Second resonance peak 1111: first piezoelectric element 1120: mass element 1121: cover plate 1130: elastic element 1200: acoustic output device 1210: piezoelectric element 1211: first piezoelectric element 1212: second piezoelectric element 1220: mass element 1230: elastic element 1231: outer ring elastic element 1232: inner ring elastic element 1301: first resonance peak 1302: second resonance peak 1303: third resonance peak 1310: curve 1320: curve 1330: curve 1340: curve 1350: curve 1400: acoustic output device 1410: piezoelectric element 1411: first piezoelectric element 1412: second piezoelectric element 1420: mass element 1430: elastic element 1431: outer ring elastic element 1432: inner ring elastic element 1501: first resonance peak 1502: second resonance peak 1503: third resonance peak 1510: curve 1520: curve 1530: curve 1540: curve 1550: curve 1600: acoustic output device 1601: first symmetry axis 1602: second symmetry axis 1610: piezoelectric element 1611: first piezoelectric element 1612: Second piezoelectric element 1620: Mass element 1630: Elastic element 1631: Outer ring elastic element 1632: Inner ring elastic element 1701: First resonance peak 1702: Second resonance peak 1703: Third resonance peak 1710: Curve 1720: Curve 1730: Curve 1740: Curve 1801: First resonance peak 1802: Second resonance peak 1803: Third resonance peak 1810: Curve 1820: Curve 1830: Curve 1840: Curve 1900: Acoustic output device 1910: Piezoelectric element 1911: first piezoelectric element 19111: upper piezoelectric element 19112: lower piezoelectric element 19113: upper piezoelectric element 19114: lower piezoelectric element 1920: mass element 1930: elastic element 1931: first elastic element 2010: upper connection surface 2020: lower connection surface 2030: upper connection surface 2040: lower connection surface 2100: acoustic output device 2110: piezoelectric element 2111: first piezoelectric element 2112: second piezoelectric element 2120: mass element 2131: inner ring elastic element 2132: outer ring elastic element 2210: curve 2220: curve 2230: curve 2240: curve 2300: acoustic output device 2310: piezoelectric element 2320: mass element 2330: elastic element 2340: piezoelectric beam 2341: first piezoelectric sheet 2342: second piezoelectric sheet 2343: substrate 2400: acoustic output device 2421: first mass element 2422: second mass element

The present invention will be further described in the form of exemplary embodiments, which will be described in detail by the accompanying drawings. These embodiments are not restrictive, and in these embodiments, the same number represents the same structure, wherein:

FIG. 1 is an exemplary module diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 2 is an exemplary structural diagram of an elastic element according to some embodiments of the present invention;

FIG. 3 is an exemplary structural diagram of an elastic element according to some embodiments of the present invention;

FIG. 4 is an exemplary structural diagram of an elastic element according to some embodiments of the present invention;

FIG. 5 is an exemplary structural diagram of an elastic element according to some embodiments of the present invention;

FIG. 6 is a frequency response curve diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 7A is an exemplary structural diagram of an elastic element according to some embodiments of the present invention;

FIG. 7B is an exemplary structural diagram of an elastic element according to some embodiments of the present invention;

FIG. 7C is a frequency curve diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 8A is an exemplary structural diagram of an elastic element according to some embodiments of the present invention;

FIG. 8B is an exemplary structural diagram of an elastic element according to some embodiments of the present invention;

FIG. 9 is an exemplary structural diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 10 is a frequency curve diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 11A is an exemplary structural diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 11B is a frequency curve diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 12 is an exemplary structural diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 13 is a frequency response curve diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 14 is an exemplary structural diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 15 is a frequency response curve diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 16 is an exemplary structural diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 17 is a frequency curve diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 18 is a frequency curve diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 19 is an exemplary structural diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 20A is an exemplary circuit diagram of a first piezoelectric element according to some embodiments of the present invention;

FIG. 20B is another exemplary circuit diagram of the first piezoelectric element according to some embodiments of the present invention;

FIG. 21 is an exemplary structural diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 22 is a frequency response curve diagram of an acoustic output device according to some embodiments of the present invention;

FIG. 23 is an exemplary structural diagram of an acoustic output device according to some embodiments of the present invention;

[Figure 24] is an exemplary structural diagram of an acoustic output device shown in some embodiments of the present invention.

100:Acoustic output device

110: Piezoelectric components

120:Mass element

130: Elastic element

Claims (10)

An acoustic output device comprises: a piezoelectric element for converting an electrical signal into mechanical vibration; an upper elastic element and a lower elastic element, wherein the upper elastic element and the lower elastic element respectively comprise a plurality of rod structures, each of which comprises one or more bending regions; and a mass element, wherein the upper elastic element and the lower elastic element are respectively connected to the mass element and the piezoelectric element, and the mass element receives the mechanical vibration to generate an acoustic signal, wherein the upper elastic element and the lower elastic element are distributed vertically along the vibration direction of the mass element, and the projection of the upper elastic element or the lower elastic element along the vibration direction of the mass element has at least one symmetry axis. An acoustic output device as claimed in claim 1, wherein the number of the multiple rod structures is 4. An acoustic output device as claimed in claim 2, wherein the projection of the upper elastic element or the lower elastic element along the vibration direction of the mass element has two mutually perpendicular symmetry axes. An acoustic output device as claimed in claim 1, wherein the bending directions of adjacent rod structures in the multiple rod structures of the upper elastic element or the lower elastic element are opposite. An acoustic output device as claimed in claim 1, wherein the shape of the rod structure includes at least one of a broken line shape, an S shape, a spline curve shape, an arc shape and a straight line shape. An acoustic output device as claimed in claim 1, wherein at least one of the plurality of rod structures comprises a plurality of segments, and the bending directions of the plurality of segments are opposite. An acoustic output device as claimed in claim 1, wherein the elastic element and the mass element resonate to produce a first resonance peak; and the piezoelectric element resonates to produce a second resonance peak. An acoustic output device as claimed in claim 7, wherein the frequency range of the first resonance peak is 50 Hz-2000 Hz. An acoustic output device as claimed in claim 7, wherein the frequency range of the second resonance peak is 1000 Hz-50000 Hz. As in claim 1, the piezoelectric element comprises: A piezoelectric sheet for generating the mechanical vibration based on the electrical signal, wherein the electrical direction of the piezoelectric sheet is parallel to the mechanical vibration direction.