earphones

Abstract

An embodiment of the present specification discloses an acoustic output device including a vibration element. The vibration element includes a beam structure extending along a longitudinal direction. The beam structure includes a piezoelectric layer that deforms in response to an electric signal to vibrate the vibration element, and a mass element connected to a first position of the beam structure, the mass element vibrating in a direction perpendicular to the longitudinal direction due to the vibration of the vibration element, and a ratio of a distance from the first position to one end of the beam structure along the longitudinal direction of the beam structure to a length of the beam structure is within a range of 0.3 to 0.95.

Description

[Technical Field]

[0001] TECHNICAL FIELD This disclosure relates to the field of audio, and in particular to audio output devices. [Background technology]

[0002] A piezoelectric material-driven acoustic output device generates vibrations by utilizing the inverse piezoelectric effect of the piezoelectric material and radiates sound waves to the outside. Compared to conventional electromagnetic acoustic output devices, a piezoelectric material-driven acoustic output device has advantages such as high electromechanical conversion efficiency, low energy consumption, small volume, and high integration.

[0003] However, compared to conventional electromagnetic acoustic output devices, acoustic output devices driven by piezoelectric materials have poor sound quality, the reasons for which include the fact that there are many vibration modes within the target frequency range and it is not possible to form a smooth frequency response curve.

[0004] It is therefore desirable to provide an acoustic output device that can produce a relatively smooth frequency response curve within a target frequency range. Summary of the Invention [Means for solving the problem]

[0005] An embodiment of the present specification provides an acoustic output device including a vibration element, the vibration element including a beam structure extending along a longitudinal direction, the beam structure including a piezoelectric layer that deforms in response to an electric signal to vibrate the vibration element, and a mass element connected to a first position of the beam structure, the mass element vibrating in a direction perpendicular to the longitudinal direction upon vibration of the vibration element, wherein a ratio of a distance from the first position to one end of the beam structure along the longitudinal direction of the beam structure to a length of the beam structure is within a range of 0.3 to 0.95.

[0006] In some embodiments, the vibration of the mass element may have a first resonant peak and a second resonant peak in the range of 50 Hz to 10,000 Hz.

[0007] In some embodiments, the amplitude difference between a lowest point in the frequency response between the first resonant peak and the second resonant peak and the first resonant peak or the second resonant peak may be less than 40 dB.

[0008] In some embodiments, the beam structure may include a fixed end and a free end.

[0009] In some embodiments, the acoustic output device may further include a second mass element connected to the free end.

[0010] In some embodiments, the ratio between the mass of the second mass element and the mass of the beam structure may be in the range of 0 to 1.2.

[0011] In some embodiments, the ratio of the distance from the first position to the fixed end to the length of the beam structure may be in the range of 0.7 to 0.95.

[0012] In some embodiments, the ratio of the frequency range of the second resonant peak to the frequency range of the first resonant peak may be greater than 17.

[0013] In some embodiments, the vibration of the mass element may have a third resonant peak, and the amplitude difference between the lowest point in the frequency response between the second resonant peak and the third resonant peak and the second resonant peak or the third resonant peak may be less than 30 dB.

[0014] In some embodiments, the ratio of the frequency range of the third resonant peak to the frequency range of the second resonant peak may be greater than four.

[0015] In some embodiments, the ratio of the distance from the first position to the fixed end to the length of the beam structure may be in the range of 0.45 to 0.6.

[0016] In some embodiments, the beam structure may include two fixed ends.

[0017] In some embodiments, a ratio of a distance from the first position to one of the two fixed ends to a length of the beam structure may be in the range of 0.3 to 0.4.

[0018] In some embodiments, the ratio of the frequency range of the second resonant peak to the frequency range of the first resonant peak may be greater than 13.

[0019] In some embodiments, the vibration of the mass element may have a third resonant peak, and the amplitude difference between the lowest point in the frequency response between the second resonant peak and the third resonant peak and the second resonant peak or the third resonant peak may be less than 40 dB.

[0020] In some embodiments, the ratio of the frequency range of the third resonant peak to the frequency range of the second resonant peak may be greater than two.

[0021] In some embodiments, a ratio of a distance from the first position to one of the two fixed ends to a length of the beam structure may be in the range of 0.45 to 0.5.

[0022] In some embodiments, a ratio of a distance from the first position to one side of the beam structure along a width direction of the beam structure to a width of the beam structure may be in a range of 0.15 to 0.3.

[0023] In some embodiments, the beam structure may include a fixed end and a pivoted end, and during vibration of the vibration element, the pivoted end may rotate along an axis perpendicular to the longitudinal direction and vibration direction of the beam structure.

[0024] In some embodiments, the ratio of the distance from the first position to the fixed end to the length of the beam structure may be in the range of 0.5 to 0.6.

[0025] In some embodiments, the ratio of the frequency range of the second resonant peak to the frequency range of the first resonant peak may be greater than six.

[0026] In some embodiments, the beam structure may include two pivot ends, and during the vibration process of the vibration element, the two pivot ends may rotate along axes perpendicular to the longitudinal direction and vibration direction of the beam structure, respectively.

[0027] In some embodiments, a ratio of a distance from the first position to one of the two pivot ends to a length of the beam structure may be in the range of 0.3 to 0.4.

[0028] In some embodiments, the ratio of the frequency range of the second resonant peak to the frequency range of the first resonant peak may be greater than ten.

[0029] In some embodiments, the beam structure may include two elastic ends, and the two elastic ends may be elastically connected to a fixed support base of the acoustic output device by elastic members, respectively.

[0030] In some embodiments, the beam structure may be a two-end symmetrical structure, and the elastic members corresponding to the two elastic ends may be symmetrically installed along the length or width direction of the beam structure.

[0031] In some embodiments, the frequency range of the first resonant peak may be between 300 Hz and 700 Hz.

[0032] In some embodiments, the ratio of the distance from the first position to one of the two elastic ends to the length of the beam structure may be in the range of 0.1 to 0.25.

[0033] In some embodiments, the acoustic output device may further include a third vibration element that may include a third beam structure, and the beam structure and the third beam structure may have one fixed end and the other end connected by an elastic connecting member.

[0034] In some embodiments, the number of the vibration elements may be two or more, and the beam structure of each of the two or more vibration elements may include a fixed end and a free end.

[0035] In some embodiments, the mass element may be connected to a first position of a beam structure of each of the two or more vibration elements, and a ratio of a distance between the first position of each beam structure and a fixed end of the beam structure to a length of the beam structure may be in the range of 0.7 to 0.95. [Brief explanation of the drawings]

[0036] [Figure 1] FIG. 1 is a block diagram of an exemplary acoustic output device in accordance with some embodiments of the present disclosure. [Figure 2] FIG. 1 is a schematic diagram of an example beam structure in accordance with some embodiments herein. [Figure 3] FIG. 10 is a frequency response curve diagram of different position points in a beam structure in accordance with some embodiments herein. [Figure 4] FIG. 1 is a schematic block diagram of an example beam structure according to some embodiments herein. [Figure 5] 10A-10C illustrate frequency response curves of different longitudinal positions of a beam structure in an unloaded and loaded state in accordance with certain embodiments herein; [Figure 6] FIG. 10 is a diagram illustrating the relationship between the ratio of the mass of the second mass element to the beam structure and the ratio of the distance from the first position to the fixed end to the length of the beam structure according to some embodiments of the present specification. [Figure 7] FIG. 1 is a schematic block diagram of an example beam structure according to some embodiments herein. [Figure 8]1 is a schematic diagram of a pivot end according to some embodiments of the present disclosure. [Figure 9] FIG. 1 is a schematic block diagram of an example beam structure according to some embodiments herein. [Figure 10] FIG. 1 is a schematic block diagram of an example beam structure according to some embodiments herein. [Figure 11A] FIG. 1 is a schematic block diagram of an example beam structure according to some embodiments herein. [Figure 11B] 11B is a schematic diagram of vibration modes of the beam structure shown in FIG. 11A. [Figure 12] FIG. 10 illustrates frequency response curves of different longitudinal positions of a beam structure in accordance with some embodiments herein. [Figure 13] FIG. 10 is a frequency response curve diagram of different position points in the width direction of a beam structure in accordance with some embodiments of the present disclosure. [Figure 14A] FIG. 1 is a schematic diagram of a beam structure according to some embodiments of the present disclosure. [Figure 14B] 14B is a schematic diagram of vibration modes of the beam structure shown in FIG. 14A. [Figure 15] FIG. 10 is a frequency response curve diagram of different position points in a beam structure in accordance with some embodiments herein. [Figure 16A] FIG. 1 is a schematic diagram of a beam structure according to some embodiments of the present disclosure. [Figure 16B] 16B is a schematic diagram of vibration modes of the beam structure shown in FIG. 16A. [Figure 17] FIG. 10 is a frequency response curve diagram of different position points in a beam structure in accordance with some embodiments herein. [Figure 18] 1 is a partial schematic diagram of an acoustic output device according to some embodiments of the present disclosure. [Figure 19] 1 is a schematic diagram of an acoustic output device according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0037] In order to more clearly describe the technical means of the embodiments of the present application, the drawings necessary for describing the embodiments will be briefly described below. Obviously, the drawings described below are only some examples or embodiments of the present application, and those skilled in the art can apply the present application to other similar scenarios based on these drawings without any creative effort. Unless otherwise clear from the language environment or specified, the same symbols in the drawings represent the same structures or operations.

[0038] It should be understood that the terms "system," "device," "unit," and / or "module" used herein are ways of distinguishing between various assemblies, elements, components, parts, or structures at different levels, however, other terms may be used in place of the above terms if they achieve the same purpose.

[0039] As used herein and in the claims, unless the context clearly dictates otherwise, terms such as "a," "one," "an," "one," and / or "the" do not specifically refer to the singular but may include the plural. In general, the terms "comprise" and "containing" merely indicate the inclusion of explicitly identified steps and elements, and these steps and elements are not an exclusive list, and a method or apparatus may include other steps or elements.

[0040] Examples of the present disclosure describe an acoustic output device, which may include a vibration element including a beam structure extending along a longitudinal direction. In some examples, the beam structure may include a piezoelectric layer, and the piezoelectric layer may deform in response to an electrical signal due to the inverse piezoelectric effect, thereby vibrating the vibration element. In some examples, the acoustic output device may further include a mass element connected to a first position on the beam structure, and vibration of the vibration element may cause the mass element to vibrate in a direction perpendicular to the longitudinal direction of the beam structure, thereby generating sound. In some examples, since different positions at which the mass element is connected to the beam structure along the longitudinal direction result in different vibration modes output through the mass element and different frequency response curves of the acoustic output device, an appropriate first position at which the mass element is connected to the beam structure may be determined to produce a relatively smooth frequency response curve of the acoustic output device. In the embodiments of the present specification, by setting the first position (e.g., adjusting the ratio between the distance from the first position to one end of the beam structure and the length of the beam structure), the frequency response curve of the audio output device has no or few resonance dips within a target frequency range (e.g., 50 Hz to 10,000 Hz), or the amplitude difference between the resonance peak and the resonance dip is reduced, thereby obtaining a relatively smooth frequency response curve and ensuring that the audio output device has good sound quality.

[0041] 1 is a block diagram of an exemplary acoustic output device according to some embodiments of the present disclosure. As shown in FIG. 1, the acoustic output device 100 may include a vibration element 110 and a mass element 120.

[0042] The audio output device 100 may convert an audio signal (e.g., an electrical signal containing audio information) into an audio signal. In some embodiments, the audio output device 100 may be a bone conduction audio output device, an air conduction audio output device, or an audio output device that combines bone conduction and air conduction. In some embodiments, the audio output device 100 may be applied to glasses, a smart bracelet, earphones, hearing aids, a smart helmet, a smart watch, smart clothing, a smart backpack, a smart accessory, or any combination thereof. For example, the audio output device 100 may be applied to functional myopia glasses, reading glasses, cycling glasses, or sunglasses, or may be smart glasses such as audio glasses with earphone functionality. In some embodiments, the audio output device 100 may be applied to a head-mounted device such as a helmet, an augmented reality (AR) device, or a virtual reality (VR) device. In some embodiments, the augmented reality device or virtual reality device may include a virtual reality helmet, virtual reality glasses, an augmented reality helmet, augmented reality glasses, or any combination thereof. For example, the virtual reality and / or augmented reality device may include Google Glass®, Oculus Rift®, Hololens®, Gear VR®, etc.

[0043] The vibration element 110 may convert an audio signal into mechanical vibrations. In some embodiments, the vibration element 110 may include a beam structure 111 extending along a longitudinal direction. In some embodiments, the beam structure 111 may be a cantilever beam with one end fixed (e.g., as shown in FIG. 2). In some embodiments, the beam structure 111 may be a beam with one end fixed and the other end pivoted (e.g., as shown in FIG. 7). In some embodiments, the beam structure 111 may be a beam with both ends pivoted (e.g., as shown in FIG. 10). In some embodiments, the beam structure 111 may be a beam with both ends fixed (e.g., as shown in FIG. 11A). In some embodiments, the beam structure 111 may be a beam with both ends elastically supported (e.g., as shown in FIG. 14A). In some embodiments, the beam structure 111 may be a beam with an intermediate portion elastically supported (e.g., as shown in FIG. 16A). In some embodiments, the number of vibration elements 110 may be two or more (e.g., as shown in FIG. 19).

[0044] In some embodiments, the vibration element 110 may have a sheet-like or rod-like structure, etc. In some embodiments, the material of the vibration element 110 may be a material having vibration transmission capabilities. For example, the material of the vibration element 110 may include silicone rubber, foam sponge, plastic, rubber, metal, etc., or any combination thereof. In some embodiments, the vibration element 110 may be a component having high elasticity (i.e., prone to elastic deformation). For example, the vibration element 110 may include a spring (e.g., an air spring, a mechanical spring, an electromagnetic spring, etc.), a vibration transmission sheet, a spring plate, a substrate, etc., or any combination thereof.

[0045] In some embodiments, the beam structure 111 may include a piezoelectric layer 1112. The piezoelectric layer 1112 may deform in response to an electric signal (e.g., an electric signal containing audio information), thereby vibrating the beam structure 111. For example, due to the inverse piezoelectric effect, the piezoelectric layer 1112 may deform in response to an electric signal, thereby vibrating the beam structure 111 (or the vibrating element 110) along the polarization direction of the piezoelectric layer 1112. In some embodiments, the vibration direction of the beam structure 111 may be perpendicular to the longitudinal direction of the beam structure 111 (i.e., the long axis direction of the beam structure 111). In some embodiments, the piezoelectric layer 1112 may be composed of a material having a piezoelectric effect (inverse piezoelectric effect), and exemplary piezoelectric materials may include piezoelectric ceramics, piezoelectric crystals, piezoelectric polymers (e.g., polyvinyl fluoride), etc., or any combination thereof. In some embodiments, the piezoelectric layer 1112 may have any shape, such as a film, a sheet, a block, a pillar, etc., or any combination thereof. In some embodiments, the piezoelectric layer 1112 may be in the form of a sheet that conforms to the shape of the beam structure 111. In some embodiments, the piezoelectric layer 1112 may be directly attached to the beam structure 111 by adhesive bonding, deposition, or the like. In some embodiments, the piezoelectric layer 1112 may be connected to the beam structure 111 by locking, snap-fitting, or the like. In some embodiments, the piezoelectric layer 1112 may be attached to the beam structure 111 by physical deposition or chemical deposition. For more information regarding the vibration element, please refer to other parts of this specification, such as Figures 2, 5, 7, etc., and their associated descriptions.

[0046] The mass element 120 may be a member having a mass. In some embodiments, the mass element 120 may include a diaphragm, a vibrating membrane, or the like so that the acoustic output device 100 can output vibrations through the mass element 120. In some embodiments, the mass element 120 may have any shape, for example, a regular or irregular structure such as a cylinder, a rectangular parallelepiped, a cone, a truncated cone, or a sphere. In some embodiments, the material of the mass element 120 may include, but is not limited to, a material having a certain stiffness, such as plastic, wood, or metal. In some embodiments, the material of the mass element 120 may further include various metamaterials, such as negative stiffness materials or cubic stiffness materials, which help expand the audio bandwidth of the acoustic output device 100. In some embodiments, the mass element 120 may be connected to a first position of the beam structure 111. Vibration of the first position of the beam structure 111 causes the mass element 120 to vibrate in the same direction as the vibrating element 110 (i.e., a direction perpendicular to the longitudinal direction of the beam structure 111). The mass element 120 may be directly connected to the first position of the beam structure 111, or may be connected to the first position of the beam structure 111 via a connecting rod (e.g., if the mass element 120 is a vibrating membrane, the center of the vibrating membrane may be connected to the first position of the beam structure 111 via a connecting rod). For convenience of explanation, the connecting rod may be considered to be part of the mass element 120.

[0047] In some embodiments, adjusting the first position of the mass element 120 connected to the beam structure 111 can adjust the position of a resonance dip in the frequency response curve of the audio output device 100 without changing or essentially changing the position of the resonance peak. This can reduce the uneven range in the frequency response curve due to the resonance peak and the resonance dip, or, if the frequency positions of the resonance peak and the resonance dip are identical, can cancel each other out, resulting in a smooth curve with a wide frequency range and improving the sound quality of the audio output device. The resonance peak here refers to a peak with a high amplitude in the frequency response curve corresponding to the beam structure 111 (or the first position). The resonance peak may be generated by the beam structure resonating near its resonance frequency. In some embodiments, the beam structure 111 may have multiple resonance frequencies, and accordingly, the frequency response curve may have multiple resonance peaks. The resonance dip refers to a dip with a low amplitude in a frequency response curve corresponding to the beam structure 111 (or the first position). Causes of the resonance dip include, but are not limited to, split vibrations generated by the piezoelectric layer of the beam structure 111, which cause the radiated sound pressure of the beam structure 111 to cancel out in antiphase at the first position, making it difficult to output vibrations. In some embodiments, the piezoelectric layer can generate split vibrations near multiple frequencies, and accordingly, the frequency response curve can have multiple resonance dips. By adjusting the first position at which the mass element 120 is connected to the beam structure 111, the resonance peaks and resonance dips in the frequency response curve of the audio output device 100 can be canceled out, resulting in a smooth curve with a wide frequency range and improving the sound quality of the audio output device. In some embodiments, the ratio of the distance from the first position to one end of the beam structure 111 to the length of the beam structure 111 can be within a range of 0.1 to 0.99. In some embodiments, the ratio of the distance from the first position to one end of the beam structure 111 to the length of the beam structure 111 may be in the range of 0.2 to 0.95.In some embodiments, the ratio of the distance from the first position to one end of the beam structure 111 to the length of the beam structure 111 may be within a range of 0.3 to 0.95. For example, by determining the first position at which the first resonance dip and the second resonance peak are canceled out, the frequency response curve of the acoustic output device 100 may have a first resonance peak and a second resonance peak, the ratio of the frequency range between the first resonance peak and the second resonance peak is greater than 17, and the amplitude difference between the lowest point of the frequency response between the first resonance peak and the second resonance peak and the first resonance peak or the second resonance peak is less than 40 dB, thereby obtaining a frequency response curve of the acoustic output device 100 with a wide, smooth curve at low frequencies. Furthermore, for example, by determining a first position where the first resonance dip and the third resonance peak are canceled out, the frequency response curve of the audio output device 100 may have a first resonance peak, a second resonance peak, and a third resonance peak, with a smooth transition between the first resonance peak and the second resonance peak, a smooth transition between the second resonance peak and the third resonance peak, and a frequency range ratio between the second resonance peak and the third resonance peak greater than 4, thereby obtaining a smooth curve with a wide frequency band at high frequencies of the frequency response curve of the audio output device 100. For more detailed explanation regarding the determination of the first position, please refer to FIGS. 3, 7, 10 to 16B and their related descriptions, and further explanation will be omitted here. For convenience of explanation, in this specification, the effect of improving amplitude achieved when the frequency positions of the resonance peak and the resonance dip are close to or the same is referred to as peak-dip cancellation. Alternatively, the cancellation of peaks and dips described in this specification may include cancellation of the resonance peak and the resonance dip when the frequency positions of the resonance peak and the resonance dip are the same, or may include reduction of the non-flat range in the frequency response curve due to the resonance peak and the resonance dip when the frequency positions of the resonance peak and the resonance dip are close to each other, or reduction of the amplitude near the resonance peak and / or increase of the amplitude near the resonance dip.

[0048] In some embodiments, the acoustic output device 100 may further include a second vibration element, which may include a second beam structure, which may be connected to the beam structure 111. In some embodiments, the longitudinal direction of the second beam structure is perpendicular to a projection of the longitudinal direction of the beam structure 111 along the vibration direction of the vibration element 110. For more information on the acoustic output device 100 may further include a second vibration element, please refer to Figure 18 and / or Figure 19 and their related descriptions, and further description will be omitted here.

[0049] In some embodiments, the acoustic output device 100 may further include a third vibration element, which may include a third beam structure, and the third beam structure may be flexibly connected to the beam structure 111 in a plane perpendicular to the vibration direction of the beam structure 111. In some embodiments, the third beam structure extends along the longitudinal direction of the beam structure 111, and the beam structure 111 and the third beam structure have one fixed end and the other connected by an elastic connecting member. For a more detailed description of the third vibration element, please refer to FIG. 19 and its related description, and a description thereof will be omitted here.

[0050] Note that the above description of FIG. 1 is provided for explanatory purposes only and does not limit the scope of the present application. Those skilled in the art may make various changes and modifications based on the description of the present application. For example, in some embodiments, the audio output device 100 may further include one or more components (e.g., a signal transceiver, an interaction module, a battery, etc.). In some embodiments, one or more components of the audio output device 100 may be replaced by other elements capable of achieving similar functions. These changes and modifications do not depart from the scope of the present application.

[0051] 2 is a schematic diagram of an exemplary beam structure according to some embodiments of the present disclosure. As shown in FIG. 2, the beam structure 211 may be a cantilever beam, with one end of the beam structure 211 being a fixed end 2111 and the other end being a free end 2112 spaced apart from the fixed end 2111 in the longitudinal direction (x-direction shown in FIG. 2).

[0052] The fixed end 2111 refers to a position in the beam structure 211 in an operating state where the vibration acceleration or acceleration level is less than a vibration acceleration threshold or acceleration level threshold and the rotation angle of its cross section is less than a rotation angle threshold. By way of example only, the fixed end 2111 may have a vibration acceleration level less than 5 dB, 3 dB, 1 dB, 0.8 dB, 0.6 dB, 0.4 dB, 0.2 dB, or 0.05 dB, etc., and a rotation angle of its cross section less than 3°, 2°, 1°, 0.5°, 0.2°, or 0.05°, etc. In some embodiments, the fixed end 2111 is connected to a fixed position or structure (e.g., a housing) of the acoustic output device. The fixed position or structure here may refer to a position or structure in the acoustic output device where the vibration acceleration or acceleration level is less than a vibration acceleration threshold or acceleration level threshold. In some embodiments, the fixed end 2111 may be fixed to a fixed support base 212, which is connected to a fixed position or structure of the acoustic output device. For example, the acoustic output device may include a housing (not shown in FIG. 2 ), the beam structure 211 may be installed within the housing, the fixed support base 212 may be fixed to the housing, and the fixed end 2111 of the beam structure 211 may be fixedly connected to the fixed support base 212 on the housing. The free end 2112 is an end of the beam structure 211 that is free to vibrate. In some embodiments, the free end 2112 may be suspended or unconstrained.

[0053] In some embodiments, the beam structure 211 may include a piezoelectric layer 2113 and a base layer 2114. In some embodiments, the piezoelectric layer 2113 and the base layer 2114 extend along the longitudinal direction of the beam structure 211. When the vibration element is subjected to an electric field along its thickness direction (z-direction shown in FIG. 2 ), the piezoelectric layer 2113 deforms along the longitudinal direction, thereby causing the base layer 2114 (or the vibration element) to vibrate along a direction perpendicular to the longitudinal direction of the beam structure 211. In some embodiments, the piezoelectric layer 2113 may be made of a piezoelectric material. In some embodiments, the material of the base layer 2114 includes, but is not limited to, metal, alloy, glass fiber, carbon fiber, etc., or any combination thereof. In some embodiments, the piezoelectric layer 2113 and the base layer 2114 may be stacked in the thickness direction of the beam structure 211. In some embodiments, the beam structure 211 may include a multi-layer piezoelectric layer 2113 and a base layer 2114, where the multi-layer piezoelectric layer 2113 and the base layer 2114 are stacked in the thickness direction.

[0054] The mass element may be connected to a first position of the beam structure 211. In some embodiments, the first position of the beam structure 211 may be a different position along the longitudinal direction of the beam structure 211, such as point a, b, c, d, e, f, g, etc., as shown in FIG. 2 . In some embodiments, the vibration modes of the different first positions of the beam structure 211 are different, and the vibration modes output to the mass elements connected to the first positions are accordingly different, resulting in different frequency response curves of the acoustic output device; see, in particular, FIG. 3 and its related description.

[0055] FIG. 3 is a diagram illustrating frequency response curves of different positions on a beam structure according to some embodiments of the present disclosure. As shown in FIG. 3, curves 31, 32, 33, 34, 35, 36, and 37 are frequency response curves of points a, b, c, d, e, f, and g on the beam structure 211 (i.e., the cantilever beam) shown in FIG. 2 when the beam structure 211 vibrates. In some embodiments, the mass elements have little or no effect on the vibration of the beam structure 211, and the curves 31 to 37 may represent frequency response curves of the acoustic output device (e.g., the acoustic output device 100) when the mass elements are connected to the seven first positions, respectively.

[0056] 3, within the range of 50 Hz to 10,000 Hz, vibrations at different first positions on beam structure 211 all generate multiple resonant peaks (e.g., primary resonant peak A, secondary resonant peak B, tertiary resonant peak C, etc.), and the positions of the resonant peaks generated at different first positions are nearly identical. As the first position gradually approaches fixed end 2111 of beam structure 211, the resonant dips of the corresponding frequency response curves gradually shift to higher frequencies. By way of example only, comparing curves 34, 35, and 36, it can be seen that as the first position gradually moves from point f to point d toward fixed end 2111, primary resonant dip 361 corresponding to point f, primary resonant dip 351 corresponding to point e, and primary resonant dip 341 corresponding to point d gradually shift to higher frequencies. Furthermore, as can be seen with reference to curves 31 to 33 corresponding to points a to c, as the first position gradually approaches fixed end 2111 of beam structure 211, the frequency response curve of the acoustic output device becomes relatively smooth between first resonance peak A and second resonance peak B and / or between second resonance peak B and third resonance peak C. Specifically, there is a smooth transition between first resonance peak A and second resonance peak B and / or between second resonance peak B and third resonance peak C, no low resonance dip appears, and the curve between the two resonance peaks exhibits a U-shape. For example, curve 34 corresponding to point d shows a smooth transition between first resonance peak A and second resonance peak B, and curve 33 corresponding to point c shows a smooth transition between first resonance peak A and second resonance peak B and a smooth transition between second resonance peak B and third resonance peak C. Furthermore, with reference to curves 31 to 36, as the first position gradually approaches fixed end 2111 of beam structure 211, the amplitude of the low-to-mid frequencies (e.g., 50 Hz to 500 Hz in FIG. 3) of the acoustic output device gradually decreases, thereby reducing the sensitivity of the acoustic output device at low-to-mid frequencies. This allows an appropriate first position to be selected, which allows for a smooth transition of the frequency response curve between the resonance peaks of the acoustic output device in the audible range of the human ear (e.g., 50 Hz to 10,000 Hz) without excessively reducing the sensitivity of the acoustic output device at low-to-mid frequencies.In some embodiments, by setting a position within a range near point c as the first position, it is possible to improve the sound quality of the audio output device and ensure that the audio output device has high sensitivity even in mid- to low-frequency ranges. In some embodiments, the ratio of the distance from near point c to the fixed end 2111 to the length of the beam structure 211 may be in the range of 0.45 to 0.55.

[0057] Furthermore, with reference to curve 37 corresponding to point g, curve 37 smoothly transitions within the range of 500 Hz to 10,000 Hz, and specifically, there is a small or no resonance peak and / or dip between the first resonance peak A and the third resonance peak C, and the amplitude difference between the lowest point of the frequency response between the first resonance peak A and the third resonance peak C (for example, point P shown in FIG. 3) and the first resonance peak or the second resonance peak is less than 40 dB. This is because the corresponding first resonance dip and second resonance peak of curve 37 are canceled out, so that curve 37 does not have a resonance peak and / or dip near the frequency corresponding to the second resonance peak B. This allows for the selection of an appropriate first position (e.g., g-point), which cancels out the first resonance dip and the second resonance peak of the audio output device, resulting in a first resonance peak (i.e., first resonance peak A) and a second resonance peak (i.e., third resonance peak C) within the audible range of the human ear (e.g., 50 Hz to 10,000 Hz), with the frequency ratio of the second resonance peak to the first resonance peak being greater than 17, thereby increasing the frequency range corresponding to the smooth curve of curve 37 and further improving the sound quality of the audio output device. In some embodiments, the ratio of the distance from the g-point to the fixed end 2111 to the length of the beam structure 211 may be within a range of 0.75 to 0.95. In some embodiments, the ratio of the distance from the g-point to the fixed end 2111 to the length of the beam structure 211 may be within a range of 0.78 to 0.85. In some embodiments, the ratio of the distance from the g-point to the fixed end 2111 to the length of the beam structure 211 may be 0.81.

[0058] 3 and its description, an appropriate first position can be selected so that the peaks and dips in the frequency response curve of the audio output device are offset within a specific frequency range (e.g., 500 Hz to 10,000 Hz), eliminating resonant dips that cause poor frequency response in the specific frequency range and increasing the corresponding frequency range of the smooth curve in the frequency response curve of the audio output device, thereby improving the sound quality of the audio output device. In some embodiments, the first position (or the ratio of the first position to the length of the beam structure) can be determined by calculation to achieve the offset of the peaks and dips in the frequency response curve of the audio output device at the first position. In some embodiments, the displacement of each position point on the beam structure can be expressed as follows:

[0059] u(x,t)=Y(x)*φ(t) (1)

[0060] where Y(x) is a modal function, φ(t) is a harmonic function with respect to time, x represents the distance from a position point in the beam structure to one end of the beam structure (e.g., the fixed end 2111 of the beam structure 211), and u(x,t) satisfies the differential equation of motion:

[0061]

number

[0062] In the formula, E is the elastic modulus of the beam structure, I is the moment of inertia of the cross section of the beam structure, ρ is the material density of the beam structure, A is the cross-sectional area of ​​the beam structure, and F is the external force applied to the beam structure. The external force is set to F=0, and the variables are separated to obtain the eigenmode function Y(x) of the beam structure.

[0063] Y(x)=C1sinβx+C2cosβx+C3shβx+C4chβx φ(t)=C5sinwt+C6coswt) (3)

[0064] In the formula, C1 to C6 are constants,

number

[0065] Based on the above equation (3), different boundary conditions for different beam structures can be substituted, thereby determining the eigenmode functions corresponding to different beam structures. For example, the beam structure 211 shown in FIG. 2 may have zero displacement at its fixed end, zero rotation angle (proportional to the first derivative of the displacement), and zero bending moment and shear force (proportional to the second and third derivatives of the displacement, respectively) at its free end, and its boundary conditions may be Y(0) = Y'(0) = Y''(l) = Y'''(l) = 0. By substituting the above boundary conditions into equation (3), the eigenmode functions of the beam structure 211 (i.e., cantilever beam) can be obtained as follows:

[0066]

number

[0067] where i is the order corresponding to the eigenmode, and β i is ch(β i l) cos(β i l)+1=0, and we obtain β1l=1.875, β2l=4.694, β3l=7.855, …

[0068] 3 and its description, when selecting different first positions, the position of the resonance peak of the acoustic output device is relatively fixed, and as the first position gradually approaches the fixed end of the beam structure, the resonance dip gradually moves to a higher frequency, and when it moves to a frequency position that is the same as or close to the resonance peak, it can cancel out the resonance peak. Thus, the vibration node at the resonance peak of the eigenmode function of the beam structure becomes the first position that can realize the cancellation of the peak and dip of the frequency response curve of the beam structure. For the beam structure 211, Y in Equation (4) i If (x)=0, the solution is the first position where the peak and dip cancel each other out at the i (i=1, 2, 3, . . . )-th resonance peak.

[0069] By way of example only, referring to equation (4), the solution x found for Y2(x)=0 is the distance from a first position to the fixed end 2111 of the beam structure 211 at which the first resonance dip and second resonance peak of the beam structure 211 are cancelled, and the ratio of the distance from the first position to the fixed end 2111 of the beam structure 211 to the length of the beam structure 211 is approximately 0.774. Similarly, when the first resonance dip and third resonance peak of the beam structure 211 are cancelled, the ratio of the distance from the first position to the fixed end 2111 of the beam structure 211 to the length of the beam structure 211 can be found to be approximately 0.501, and when the second resonance dip and third resonance peak of the beam structure 211 are cancelled, the ratio of the distance from the first position to the fixed end 2111 of the beam structure 211 to the length of the beam structure 211 can be found to be approximately 0.868.

[0070] In some embodiments, a first position where a first resonance dip and a second resonance peak can be canceled out may be selected as a vibration output position of the acoustic output device so that the acoustic output device achieves cancellation of the peak and dip within a specific frequency range (e.g., 500 Hz to 10,000 Hz). Accordingly, the acoustic output device has a first resonance peak (e.g., first resonance peak A) and a second resonance peak (e.g., third resonance peak C) within the audible range of the human ear (e.g., 50 Hz to 10,000 Hz), and a relatively smooth curve between the first and second resonance peaks, thereby improving the sound quality of the acoustic output device in the specific frequency range. Based on the above theoretical solution and taking into account errors in actual applications, in some embodiments, the ratio of the distance from the first position to the fixed end 2111 to the length of the beam structure 211 may be within a range of 0.75 to 0.95 so that the first resonance dip and the second resonance peak of the beam structure 211 are canceled out and a smooth curve over a wide frequency range is formed between the first resonance peak and the second resonance peak of the acoustic output device. In some embodiments, the ratio of the distance from the first position to the fixed end 2111 to the length of the beam structure 211 may be within a range of 0.75 to 0.9. In some embodiments, the ratio of the distance from the first position to the fixed end 2111 to the length of the beam structure 211 may be within a range of 0.75 to 0.86. In some embodiments, the ratio of the distance from the first position to the fixed end 2111 to the length of the beam structure 211 may be within a range of 0.77 to 0.84.

[0071] In some embodiments, a first position where the first-order resonance dip and the third-order resonance peak can be canceled can be selected as a vibration output position of the acoustic output device so that the acoustic output device achieves cancellation of peaks and dips within a specific frequency range (e.g., 2000 Hz to 20000 Hz). Accordingly, the acoustic output device has a first resonance peak (e.g., first-order resonance peak A), a second resonance peak (e.g., second resonance peak B), and a third resonance peak (e.g., fourth-order resonance peak D) within the audible range of the human ear (e.g., 50 Hz to 15000 Hz). The amplitude difference between the lowest point of the frequency response between the second and third resonance peaks and either the second or third resonance peak is less than 30 dB, and the ratio of the frequency of the third resonance peak to the frequency of the second resonance peak is greater than 4. A smooth curve is formed between the second and third resonance peaks over a wide frequency range, thereby improving the sound quality of the audio output device within a specific frequency range (2000 Hz to 15000 Hz). Furthermore, the first resonance dip is shifted to a higher frequency, and a smooth transition is formed between the first and second resonance peaks, further improving the sound quality of the audio output device within a low frequency range (e.g., 500 Hz to 2000 Hz). In some embodiments, the ratio of the distance from the first position to the fixed end 2111 to the length of the beam structure 211 may be within a range of 0.45 to 0.6 to cancel out the first resonance dip and the third resonance peak of the beam structure 211 and thereby improve the sound quality of the audio output device. In some embodiments, the ratio of the distance from the first position to the fixed end 2111 to the length of the beam structure 211 may be in the range of 0.47 to 0.55. In some embodiments, the ratio of the distance from the first position to the fixed end 2111 to the length of the beam structure 211 may be in the range of 0.49 to 0.51.

[0072] It should be noted that the first positions and their ranges described in the above embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present specification. In some embodiments, different first positions are selected to cancel resonance peaks and dips of different orders (e.g., canceling the first resonance dip and the third resonance peak, canceling the second resonance dip and the third resonance peak, etc.), so that the audio output device has a wide frequency band smooth curve at different frequencies to adapt to the needs of different scenes.

[0073] FIG. 4 is a schematic diagram of an exemplary beam structure according to some embodiments of the present disclosure. The beam structure 411 shown in FIG. 4 is substantially identical to the beam structure 211 shown in FIG. 2 , with the main difference being that the beam structure 411 shown in FIG. 4 further includes a second mass element 430. As shown in FIG. 4 , the beam structure 411 includes a fixed end 4111 and a free end 4112, and the second mass element 430 is connected to the free end 4112. In some embodiments, the second mass element 430 may be similar to a mass element. In some embodiments, the second mass element 430 may be an additional mass introduced during the assembly of the beam structure 411. In some embodiments, the ratio of the mass of the second mass element 430 to the mass of the beam structure 411 may be in the range of 0 to 1.2 to prevent the mass of the second mass element 430 from being too large and affecting the vibration mode of the beam structure 411.

[0074] When the second mass element 430 is connected to the beam structure 411, the vibration mode at the first position is different from the vibration mode at the same first position when the beam structure 211 is not connected to the second mass element 430, see FIG. 5 for details.

[0075] 5 illustrates frequency response curves of different positions along the length of a beam structure in an unloaded and loaded state, according to some embodiments of the present disclosure. The unloaded state refers to a beam structure (or cantilever beam) with no added mass (e.g., beam structure 211 without second mass element 430). The loaded state refers to a beam structure 411 connected with second mass element 430. By way of example only, the second mass element 430 corresponding to the frequency response curves illustrated in FIG. 5 is 0.28 g. As illustrated in FIG. 5 , curves 511, 512, and 513 are frequency response curves of the beam structure in an unloaded state at positions 1 / 3, 1 / 2, and 2 / 3 from the free end (i.e., the distance from the first position to the free end is 1 / 3 of the length of the beam structure), respectively. Curves 521, 522, and 523 are frequency response curves of the beam structure in a loaded state at positions 1 / 3, 1 / 2, and 2 / 3 from the free end, respectively. The curves 511, 512, and 513 of the vibration of the beam structure in the unloaded state are almost identical in shape to the curves 521, 522, and 523 of the vibration of the beam structure in the loaded state, and the resonance peak of the beam structure in the loaded state shifts to a lower frequency compared to the unloaded state. This affects the ratio of the distance from the first position to the fixed end, where the peak and dip cancel each other out, to the length of the beam structure. Specifically, see FIG. 6.

[0076] FIG. 6 is a diagram illustrating the relationship between the ratio of the mass of the second mass element to the beam structure and the ratio of the distance from the first position to the fixed end to the length of the beam structure (or cantilever beam) according to some embodiments of the present disclosure. The first position here refers to a first position where peaks and dips (e.g., a first-order resonance dip and a second-order resonance peak) are canceled out. The curve shown in FIG. 6 has the abscissa m / m0 representing the ratio of the mass m of the second mass element to the mass m0 of the beam structure, and the ordinate x / l representing the ratio of the distance x from the first position to the fixed end to the length l of the beam structure. As can be seen from FIG. 6 , as the ratio of the mass of the second mass element to the beam structure increases, the ratio of the distance from the first position to the fixed end to the length l of the beam structure gradually increases. This allows the first position to be determined based on the ratio of the mass of the second mass element to the mass of the beam structure, thereby realizing cancellation of peaks and dips in the frequency response curve of the acoustic output device within the audible range of the human ear. For example, the ratio of the mass of the second mass element to the mass of the beam structure may be in the range of 0 to 1.2, and the ratio of the distance from the first position to the fixed end to the length of the beam structure (or cantilever beam) may be in the range of 0.75 to 0.95. For example, the ratio of the mass of the second mass element to the mass of the beam structure may be in the range of 0 to 0.5, and the ratio of the distance from the first position to the fixed end to the length of the beam structure (or cantilever beam) may be in the range of 0.75 to 0.92. For example, the ratio of the mass of the second mass element to the mass of the beam structure may be in the range of 0.2 to 1, and the ratio of the distance from the first position to the fixed end to the length of the beam structure (or cantilever beam) may be in the range of 0.8 to 0.95.

[0077] 7 is a schematic diagram of an exemplary beam structure according to some embodiments of the present disclosure. The beam structure 711 shown in FIG. 7 is substantially the same as the beam structure 211 shown in FIG. 2, with the main difference being that the beam structure 711 shown in FIG. 7 includes a pivot end 7112. As shown in FIG. 7, the beam structure 711 includes a fixed end 7111 and a pivot end 7112, which are opposite ends spaced apart from each other along the longitudinal direction (e.g., the x-direction shown in FIG. 7) of the beam structure 711, and the fixed end 7111 is similar to the fixed end 2111.

[0078] The pivot end 7112 is a rotatable end. In some embodiments, the pivot end 7112 has an axis (e.g., an axis parallel to the y direction shown in FIG. 7 ) perpendicular to the longitudinal direction and vibration direction (e.g., the z direction shown in FIG. 7 ) of the beam structure 711, and the pivot end 7112 can rotate around the axis. FIG. 8 is a schematic diagram of a pivot end according to some embodiments herein. In some embodiments, as shown in FIG. 8 , the pivot end 7112 may be relatively fixedly connected to a pivot pin 713 along both sides of its length (i.e., the y direction), and the axis on which the pivot pin 713 lies (the y direction shown in FIG. 8 ) is perpendicular to the longitudinal direction (the x direction shown in FIG. 8 ) and vibration direction (the z direction shown in FIG. 8 ) of the beam structure 711. Beam structure 711 (or acoustic output device) further includes a pivot seat 714, which is fixed to the acoustic output device (e.g., a housing) and may include a pivot hole 7141. Pivot pin 713 is disposed within pivot hole 7141 and can rotate within pivot hole 7141. When beam structure 711 vibrates along its vibration direction, pivot end 7112 can rotate relative to pivot seat 714 along an axis on which pivot pin 713 is located. In some embodiments, pivot pin 713 may be physically connected to pivot end 7112. In some embodiments, pivot pin 713 may be integral with pivot end 7112.

[0079] In some embodiments, similar to the cantilever beams described herein (e.g., beam structure 211, beam structure 411, etc.), a first position on beam structure 711 as shown in FIG. 7 can be determined, thereby canceling out peaks and dips in the frequency response curve of the acoustic output device, increasing the range of the frequency response curve of the acoustic output device that is a smooth curve in the audible range of the human ear, and improving the sound quality of the acoustic output device. In some embodiments, the intrinsic mode function Y of beam structure 711 including fixed end 7111 and pivot end 7112 can be determined by: i (x) may be similar to the eigenmode functions of the beam structure 211 (i.e., equation (4)), and for the eigenmode functions of the beam structure 711, β i is ch(β i l)*sin(β i l)-cos(β i l)*sh(β i l) = 0, so that the β i After obtaining the l value and substituting it into equation (4), the solution to Yi(x)=0 in equation (4) is the distance from the first position where the peak and dip cancel each other out at the i (i=1, 2, 3, ...)th resonance peak to the fixed end 7111 of the beam structure 711.

[0080] By way of example only, referring to equation (4), the solution x found for Y2(x)=0 is the distance from a first position to the fixed end 7111 of the beam structure 711 at which the first resonance dip and second resonance peak of the beam structure 711 are cancelled out, and the ratio of the distance from the first position to the fixed end 7111 of the beam structure 711 to the length of the beam structure 711 is found to be approximately 0.56. Similarly, when the first resonance dip and third resonance peak of the beam structure 711 are cancelled out, the ratio of the distance from the first position to the fixed end 7111 of the beam structure 711 to the length of the beam structure 711 is found to be approximately 0.39 and 0.69.

[0081] In some embodiments, by selecting a first position in the beam structure 711 where the first resonance dip and the second resonance peak can be canceled out as the vibration output position, the audio output device has a first resonance peak (e.g., first resonance peak A shown in Figure 3) and a second resonance peak (e.g., third resonance peak C shown in Figure 3) in the audible range of the human ear (e.g., 50 Hz to 10,000 Hz), and a relatively smooth curve between the first resonance peak and the second resonance peak, thereby improving the sound quality of the audio output device in the specific frequency range. Based on the theoretical solution and taking into account errors in practical applications, in some embodiments, the ratio of the distance from the first position to the fixed end 7111 to the length of the beam structure 711 may be within a range of 0.5 to 0.6 so that the first resonance dip and the second resonance peak of the beam structure 711 are canceled out, the ratio of the frequency range of the second resonance peak to the frequency range of the first resonance peak is greater than 6, and a smooth curve is formed between the first resonance peak and the second resonance peak of the acoustic output device. In some embodiments, the ratio of the distance from the first position to the fixed end 7111 to the length of the beam structure 711 may be within a range of 0.52 to 0.59. In some embodiments, the ratio of the distance from the first position to the fixed end 7111 to the length of the beam structure 711 may be within a range of 0.54 to 0.58.

[0082] In some embodiments, a first position where the first resonance dip and the third resonance peak can be canceled out may be selected as the vibration output position of the beam structure 711 so that the acoustic output device achieves peak-dip cancellation. Accordingly, the acoustic output device has a first resonance peak (e.g., first resonance peak A shown in FIG. 3 ), a second resonance peak (e.g., second resonance peak B shown in FIG. 3 ), and a third resonance peak (e.g., fourth resonance peak D shown in FIG. 3 ) in the audible range of the human ear (e.g., 50 Hz to 15,000 Hz). In this case, the first resonance dip moves to a higher frequency, there is a smooth transition between the first resonance peak and the second resonance peak, and there is a smooth transition between the second resonance peak and the third resonance peak, and the frequency range of the smooth curve becomes wider, thereby improving the sound quality of the acoustic output device. In some embodiments, the ratio of the distance from the first position to the fixed end 7111 to the length of the beam structure 711 may be in the range of 0.35 to 0.45 to cancel out the first resonance dip and the third resonance peak of the beam structure 711 and improve the sound quality of the audio output device. In some embodiments, the ratio of the distance from the first position to the fixed end 7111 to the length of the beam structure 711 may be in the range of 0.36 to 0.43. In some embodiments, the ratio of the distance from the first position to the fixed end 7111 to the length of the beam structure 711 may be in the range of 0.37 to 0.41. In some embodiments, the ratio of the distance from the first position to the fixed end 7111 to the length of the beam structure 711 may be in the range of 0.65 to 0.75 to cancel out the first resonance dip and the third resonance peak of the beam structure 711 and improve the sound quality of the audio output device. In some embodiments, the ratio of the distance from the first position to the fixed end 7111 to the length of the beam structure 711 may be in the range of 0.67 to 0.72. In some embodiments, the ratio of the distance from the first position to the fixed end 7111 to the length of the beam structure 711 may be in the range of 0.68 to 0.7.

[0083] FIG. 9 is a schematic diagram of an exemplary beam structure according to some embodiments of the present disclosure. The beam structure 911 shown in FIG. 9 is substantially identical to the beam structure 711 shown in FIG. 7 , with the main difference being that the beam structure 911 shown in FIG. 9 includes an elastic end 9112. As shown in FIG. 9 , the beam structure 911 includes a fixed end 9111 and an elastic end 9112, which are opposite ends of the beam structure 911 that are spaced apart from each other. The fixed end 9111 is similar to the fixed end 7111. The elastic end 9112 is one end of the beam structure 911 that is elastically connected to another assembly (e.g., a housing) of the acoustic output device. In some embodiments, the eigenmode functions of the beam structure 911 obtained by substituting boundary conditions may be similar to the eigenmode functions of the beam structure 211 (i.e., Equation (4)), and the eigenmode functions of the beam structure 911 may be expressed as follows: i teeth,

[0084]

number

[0085] Fig. 10 is a schematic diagram of an exemplary beam structure according to some embodiments of the present disclosure. The beam structure 1011 shown in Fig. 10 is substantially the same as the beam structure 711 shown in Fig. 7, with the main difference being that the beam structure 1011 shown in Fig. 10 includes two pivot ends 10111 and 10112. As shown in Fig. 10, the two pivot ends 10111 and 10112 are opposite ends of the beam structure 1011 that are spaced apart from each other, and the pivot ends 10111 and 10112 may be similar to the pivot end 7112.

[0086] 10 , a first position on the beam structure 1011 can be determined, which offsets peaks and dips in the frequency response curve of the acoustic output device, thereby increasing the range of the frequency response curve of the acoustic output device that is a smooth curve in the audible range of the human ear, and improving the sound quality of the acoustic output device. In some embodiments, the eigenmode functions of the beam structure 1011 obtained by substituting boundary conditions can be expressed as follows:

[0087] Y i (x)=sin(β i x) (5)

[0088] In the formula, β i is sin(β i l) = 0, and each β i The value of l is obtained and substituted into equation (5), and Y in equation (5) is i The solution where (x)=0 is the first position where the peak and dip cancel each other out at the i (i=1, 2, 3, . . . )-th resonance peak.

[0089] By way of example only, and referring to equation (5), in some embodiments, the beam structure 1011 may be symmetrical at both ends (i.e., pivot ends 10111 and 10112), and when actually driven by a piezoelectric, the even-order resonant modes disappear, leaving only odd-order resonant peaks. If the first-order resonant dip and the third-order resonant peak of the beam structure 1011 are to be canceled out, the ratio of the distance from the first position to the pivot end 10111 of the beam structure 1011 to the length of the beam structure 1011 is required to be approximately 0.33 or 0.67.

[0090] In some embodiments, a first position on the beam structure 1011 where the first resonance dip and the third resonance peak can be canceled out may be selected as the vibration output position so that the acoustic output device achieves peak-dip cancellation. Accordingly, the acoustic output device has a first resonance peak, a second resonance peak, and a third resonance peak in the audible range of the human ear (e.g., 50 Hz to 15,000 Hz). In this case, the first resonance dip moves to a higher frequency, there is a smoother transition between the first resonance peak and the second resonance peak, and there is a smoother transition between the second resonance peak and the third resonance peak, and the frequency range of the smooth curve becomes wider, thereby improving the sound quality of the acoustic output device. By way of example only, the ratio of the frequency range of the second resonance peak to the frequency range of the first resonance peak may be greater than 10. In some embodiments, the ratio of the distance from the first position to one of the two pivot ends 10111 and the length of the beam structure 1011 may be in the range of 0.3 to 0.4 so that a smooth curve is formed between the first and second resonance peaks and the frequency range of the smooth curve is wider, i.e., the first resonance dip and the third resonance peak of the beam structure 1011 are canceled out. In some embodiments, the ratio of the distance from the first position to one of the two pivot ends 10111 and the length of the beam structure 1011 may be in the range of 0.3 to 0.37. In some embodiments, the ratio of the distance from the first position to one of the two pivot ends 10111 and the length of the beam structure 1011 may be in the range of 0.31 to 0.35.

[0091] 11A is a schematic diagram of an exemplary beam structure according to some embodiments of the present disclosure. The beam structure 1111 shown in FIG. 11A is substantially the same as the beam structure 211 shown in FIG. 2, with the main difference being that the beam structure 1111 shown in FIG. 11A includes a fixed end 11111 and a fixed end 11112. As shown in FIG. 11A, the two fixed ends are opposite ends of the beam structure 1111 that are spaced apart from each other along the longitudinal direction (e.g., the x-direction shown in FIG. 11A), and the fixed ends may be similar to the fixed end 2111.

[0092] 11A , a first position on the beam structure 1111 can be determined, which offsets peaks and dips in the frequency response curve of the acoustic output device, thereby increasing the range of the frequency response curve of the acoustic output device that is a smooth curve in the audible range of the human ear, and improving the sound quality of the acoustic output device. In some embodiments, the eigenmode functions of the beam structure 1111 obtained by substituting boundary conditions can be expressed as follows:

[0093]

number

[0094] In the formula, β i is cos(β i l)*ch(β i l) = 1, and each β i The values ​​of l are obtained as β1l = 4.73, β2l = 7.85, β3l = 10.99, .... Substituting this into equation (6), Y in equation (6) iSetting (x)=0 gives the ratio of the distance from the first position where the peaks and dips of each order are cancelled to the fixed end 11111 to the length of the beam structure 1111. By way of example only, when actually driven by piezoelectrics under symmetric boundary conditions, the even-order resonant modes disappear and only the odd-order resonant peaks remain, and by referring to equation (6), the ratio of the distance from the first position where the first-order resonant dip and the third-order resonant peak in the beam structure 1111 are cancelled to the fixed end of one of them to the length of the beam structure 1111 is required to be approximately 0.36 or 0.64.

[0095] In some embodiments, the beam structure 1111, including the fixed ends 11111 and 11112, may be a two-sided symmetric structure, i.e., the beam structure 1111 is symmetric along an axis L, which passes through the midpoint O and is parallel to the width direction y of the beam structure 1111. In some embodiments, the electrodes of the piezoelectric layer in the beam structure 1111 may be symmetric along the axis L. As a result, when the beam structure 1111 vibrates, the stress experienced by the beam structure 1111 on both sides of the axis L is distributed symmetrically, and the rotation angle of the midpoint O is zero. The rotation angle of a point here may refer to the angular displacement of the cross section of the beam structure in which the point is located rotates around its neutral axis (e.g., the x-axis or z-axis shown in FIG. 11A ) after the beam structure vibrates (or deforms). FIG. 11B is a schematic diagram of the vibration modes of the beam structure 1111 shown in FIG. 11A . As shown in FIG. 11B, (a), (b), and (c) respectively show the first, third, and fifth vibration mode curves of the beam structure 1111. The first, third, and fifth vibration mode curves correspond to the first, third, and fifth vibration mode functions Y1, Y3, and Y5 shown in equation (6), respectively. The horizontal axis represents each point on the beam structure 1111, and the vertical axis represents the natural mode function Y of the beam structure 1111. i (x), and the intersection of the vibration mode curve with the horizontal axis (i.e., Y i(x)=0) is the vibration node of the beam structure 1111. Note that, since the stresses received on both sides of the midpoint O are distributed symmetrically, the rotation angle of the midpoint O should be 0. Accordingly, when the beam structure 1111 is driven by a piezoelectric, the even-order resonance modes disappear and only the odd-order resonance modes remain. Therefore, as shown in FIG. 11B, the actual vibration of the beam structure 1111 does not include the even-order vibration modes (e.g., the frequency response curve of the beam structure 1111 does not include the second-order peak, second-order dip, fourth-order peak, fourth-order dip, etc.). Further referring to (a), (b), and (c) in FIG. 11B, the mode function Y i (x) does not intersect with the horizontal axis at the midpoint O, and therefore the midpoint O of the beam structure 1111 cannot be the vibration node of the beam structure 1111, nor can it be the offset point between the peak and the dip.

[0096] 12 is a diagram illustrating frequency response curves of different position points in the longitudinal direction of a beam structure according to some embodiments of the present disclosure. As shown in FIG. 12, curves 121, 122, 123, 124, and 125 are frequency response curves of five position points where the ratios of the distance from a position point to one fixed end of the beam structure 1111 shown in FIG. 11A to the length of the beam structure 1111 are 0.31, 0.36 (i.e., the theoretical first position where the first-order resonance dip and the third-order resonance peak are canceled), 0.41, 0.45, and 0.5, respectively, and can represent the frequency response curves of an acoustic output device when mass elements are connected to the five position points.

[0097] As can be seen from Figure 12, the frequency response curves corresponding to the above five positions have multiple resonance peaks (e.g., resonance peak E, resonance peak F, resonance peak G, etc.) within the range of 50 Hz to 20,000 Hz, and when the vibration output point (first position) moves from the midpoint to the fixed end, the frequency response curve is expressed such that the frequency position of each resonance peak does not change basically, and the resonance dip gradually moves from high frequency to low frequency. The frequency f corresponding to resonance peak E E and the frequency f corresponding to the resonance peak F Fand the frequency f corresponding to the resonant peak G G The ratio of E :f F :f G =1:5.36:13.06. The resonance frequencies of each order in the beam structure 1111 can be expressed as follows:

[0098]

number

[0099] According to equation (7), the ratio of the frequency f1 corresponding to the first resonance peak of the beam structure 1111 to the frequency f3 corresponding to the third resonance peak and the frequency f5 corresponding to the fifth resonance peak is f1:f3:f5=(β1l) 2 :(β3l) 2 :(β5l) 2 Further, with reference to the formula (6), each order β i Calculating the value of l, we get f1:f3:f5=1:5.40:13.35. E :f F :f G As can be seen from the comparison, resonance peak E, resonance peak F, and resonance peak G may be the first, third, and fifth order resonance peaks, respectively, and the vibration of beam structure 1111 does not include even order vibration modes.

[0100] Furthermore, as shown in curve 122, when the resonance dip moves near the frequency corresponding to the third resonance peak F, a cancellation of the peak and dip with the third resonance peak F can occur, forming a smooth curve with a wide frequency band from the first resonance peak E to the fifth resonance peak G (within the range of 1000 Hz to 13000 Hz). Thus, in some embodiments, the first position may be adjusted to cancel the first resonance dip and the third resonance peak of the beam structure 1111. In this case, the frequency response curve of the audio output device may have a first resonance peak (i.e., the first resonance peak E) and a second resonance peak (i.e., the fifth resonance peak G), and the frequency range ratio of the second resonance peak to the first resonance peak is greater than 13 (e.g., f1:f5=1:13.35). A smooth curve with a wide frequency band exists between the first resonance peak and the second resonance peak, thereby improving the sound quality of the audio output device. 12, in some embodiments, the ratio of the distance from the first position to one of the two fixed ends to the length of the beam structure 1111 may be in the range of 0.3 to 0.4. In some embodiments, the ratio of the distance from the first position to one of the two fixed ends to the length of the beam structure 1111 may be in the range of 0.32 to 0.4. In some embodiments, the ratio of the distance from the first position to one of the two fixed ends to the length of the beam structure 1111 may be in the range of 0.34 to 0.38.

[0101] Furthermore, as can be seen with reference to curves 123, 124, and 125, the frequency response curve of the vibration output point near the midpoint of beam structure 1111 has a large resonance dip (e.g., resonance dip H shown in FIG. 12 ). This is because a curl mode occurs in the width direction (e.g., the y direction shown in FIG. 11A ) of beam structure 1111, which affects the amplitude of the resonance dip in the frequency response curve. Furthermore, as shown in curve 125, the first position can be adjusted to near the midpoint of beam structure 1111 in the longitudinal direction. In this case, ignoring the influence of the curl mode, the frequency response curve of the audio output device has a first resonance peak (i.e., first-order resonance peak E), a second resonance peak (i.e., third-order resonance peak F), and a third resonance peak (i.e., fifth-order resonance peak G), with smooth transitions between first-order resonance peak E and third-order resonance peak F, and between third-order resonance peak F and fifth-order resonance peak G, thereby improving the sound quality of the audio output device. 12, the amplitude difference between the lowest point of the frequency response between the second and third resonant peaks and either the second or third resonant peak is less than 40 dB, the ratio of the third resonant peak to the frequency range of the second resonant peak is greater than 2, and there is a smooth transition between the second and third resonant peaks. In some embodiments, the ratio of the distance from the first position to one of the two fixed ends to the length of the beam structure 1111 may be in the range of 0.45 to 0.5.

[0102] 13 is a frequency response curve diagram of different position points in the width direction of a beam structure according to some embodiments of the present disclosure. As shown in FIG. 13, curves 131, 132, 133, 134, 135, and 136 are frequency response curves of six position points of the beam structure 1111 shown in FIG. 11A , where the ratios of the distance from the position point to a side edge 11113 to the width of the beam structure 1111 are 0.5, 0.4, 0.3, 0.22, 0.1, and 0, respectively. Side edge 11113 is one of the two sides perpendicular to the width direction of the beam structure 1111, and all of the six position points are midpoints in the longitudinal direction. Among the six curves, curve 134 is smoother than the other curves, and there are smooth transitions between the first-order resonance peak E and the third-order resonance peak F, and between the third-order resonance peak F and the fifth-order resonance peak G.

[0103] The widthwise curl mode of the beam structure 1111 can be approximated to the first mode of a beam structure with both ends free, and its first-order eigenmode function can be expressed as follows:

[0104]

number

[0105] In the formula, x' represents the distance from a point on the beam structure 1111 to the side edge 11113, and L represents the width of the beam structure. When Y(x')=0, the vibration node position of the curl mode is obtained as (x') / L=0.22. As can be seen from Figure 13, the curl mode in the width direction can be eliminated at the vibration node.

[0106] In view of the above, in order to eliminate curl modes in the width direction and to improve large-amplitude resonance dips to some extent, in some embodiments, the ratio of the distance from the first position to one side of the beam structure 1111 along the width direction of the beam structure to the width of the beam structure 1111 may be in the range of 0.1 to 0.4. In some embodiments, the ratio of the distance from the first position to one side of the beam structure 1111 along the width direction of the beam structure to the width of the beam structure 1111 may be in the range of 0.15 to 0.3. In some embodiments, the ratio of the distance from the first position to one side of the beam structure 1111 along the width direction of the beam structure to the width of the beam structure 1111 may be in the range of 0.18 to 0.36.

[0107] FIG. 14A is a schematic diagram of a beam structure according to some embodiments of the present disclosure. The beam structure 1411 shown in FIG. 14A is substantially identical to the beam structure 1111 shown in FIG. 11A, with the main difference being that the beam structure 1411 shown in FIG. 14A includes an elastic end 14111 and an elastic end 14112. As shown in FIG. 14A, the elastic end 14111 and the elastic end 14112 are opposite ends of the beam structure 1411 that are spaced apart from each other. In some embodiments, the two elastic ends may be connected to another assembly of the acoustic output device (e.g., a fixed support base or a housing of the beam structure) via the elastic member 1412.

[0108] The elastic member 1412 may be a member having elasticity. In some embodiments, the elastic member 1412 may be an elastic structure, and exemplary elastic structures may include a continuous bending structure, a spiral structure, a leaf spring structure, a mechanical spring, an air spring, an electromagnetic spring, etc., or any combination thereof. In some embodiments, the elastic member 1412 may be made of an elastic material, and exemplary elastic materials may include foam sponge, rubber, latex, silicone rubber, sponge, etc., or any combination thereof. In some embodiments, the beam structure 1411 may have a symmetrical structure at both ends. The elastic members 1412 corresponding to the elastic ends 14111 and 14112 may be symmetrically arranged along the length and / or width of the beam structure.

[0109] In some embodiments, to ensure the stability of the structure, the elastic end 14111 is connected to other assemblies of the acoustic output device via at least two elastic members 1412. In some embodiments, the at least two elastic members 1412 may be symmetrically distributed along the beam structure 1411.

[0110] FIG. 14B is a schematic diagram of the vibration mode of the beam structure 1411 shown in FIG. 14A. As shown in FIG. 14B, (a) to (e) respectively show vibration mode curves for different vibration modes of the beam structure 1411. (a) shows the initial vibration mode of the beam structure 1411. In this initial vibration mode, the beam structure 1411 begins to be driven by the piezoelectric element and first vibrates at its center, causing the elastic members 1412 on both sides to vibrate. As the frequency increases, as shown in (b), the elastic mass formed by the elastic members 1412 and the beam structure 1411 resonates, generating a first resonance peak. In some embodiments, the resonance frequency corresponding to the first resonance peak may be between 300 Hz and 700 Hz. As a mere example, the frequency response curve of the beam structure 1411 shown in FIG. 15 has a first resonance peak I near 500 Hz. Furthermore, as the frequency increases, the center of the vibration mode curve shown in (c) sinks, and its midpoint intersects with the horizontal axis. Accordingly, a vibration node occurs at the midpoint of the beam structure 1411, and the frequency response curve corresponding to the midpoint may have a resonant dip (e.g., resonant dip J shown in FIG. 15 ). As the frequency further increases, the beam structure 1411 may resonate at its natural resonant frequency, thereby generating a second resonant peak. (d) shows a resonant mode of the beam structure 1411, in which the beam structure 1411 may resonate near a resonant frequency. In some embodiments, the resonant frequency may be between 3300 Hz and 4300 Hz. By way of example only, the frequency response curve of the beam structure 1411 shown in FIG. 15 has a second resonant peak K near 3800 Hz. In this resonant mode, the center of the vibration mode curve continues to dip, generating two intersections with the horizontal axis near the ends. Accordingly, the beam structure 1411 may have vibration nodes at these two intersections, and the corresponding frequency response curve may have a resonant dip. As the frequency increases further, the beam structure 1411 may resonate at another of its natural resonant frequencies, thereby generating a third resonant peak.(e) shows a resonant mode at another natural resonant frequency of the beam structure 1411, in which the beam structure 1411 can resonate near another resonant frequency. In some embodiments, the resonant frequency may be 12 kHz to 18 kHz. By way of example only, the frequency response curve of the beam structure 1411 shown in FIG. 15 has a third resonant peak L near 15,000 Hz. In the resonant mode shown in (e), the center and two ends of the vibration mode curve dip, resulting in four intersections with the horizontal axis. Accordingly, the beam structure 1411 generates vibration nodes at these four intersections, and the corresponding frequency response curve may have resonant dips. As can be seen from FIG. 14B, in the vibration modes shown in (a) to (e), the beam structure 1411 may not always have nodes near its elastic ends (e.g., between dashed lines L1 and L2, between dashed lines L3 and L4). Accordingly, in the vibration modes (a) to (e), the frequency response curve corresponding to the position close to the elastic end may not always have a resonance dip, and the curve between each resonance peak (e.g., between the first resonance peak I and the second resonance peak K, or between the second resonance peak K and the third resonance peak L) may have a smooth transition. Thus, by selecting the position close to the elastic end as the first position, the curve between the resonance peaks of the audio output device can be smoothly transitioned, further improving the sound quality of the audio output device. In some embodiments, to achieve a smooth transition between the resonance peaks of the audio output device, the ratio of the distance from the first position to one of the elastic ends to the length of the beam structure 1411 may be within a range of 0.1 to 0.25. In some embodiments, the ratio of the distance from the first position to one of the elastic ends to the length of the beam structure 1411 may be within a range of 0.15 to 0.2.

[0111] 15 is a frequency response curve diagram of different positions of a beam structure according to some embodiments of the present disclosure. As shown in FIG. 15, curve 151 is a frequency response curve of an elastic end (e.g., elastic end 14111 or 14112) of beam structure 1411, curve 152 is a frequency response curve of a midpoint of beam structure 1411, and curve 153 is a frequency response curve of a first position of beam structure 1411, where the ratio of the distance from the first position to one of the elastic ends (e.g., elastic end 14111) to the length of beam structure 1411 is 0.2. As can be seen from curves 151 to 153, when the output position is the elastic end or the first position, the frequency response curve of the acoustic output device has no or small resonance dips in the frequency range of 500 Hz to 15,000 Hz, and there are smooth transitions between each resonance peak (e.g., between the first resonance peak I and the second resonance peak K, and between the second resonance peak K and the third resonance peak L), resulting in a better frequency response. Furthermore, as can be seen with reference to curves 151 and 153, within the low frequency range (e.g., less than 500 Hz), vibrations at the first position can have a higher amplitude than those at the elastic end. Therefore, the low-frequency sensitivity at the first position is higher than that at the elastic end. This allows the first position connected to the mass element in the beam structure 1411 to be close to the elastic end, and the ratio of the distance from the first position to one of the elastic ends to the length of the beam structure 1411 is in the range of 0.15 to 0.2, thereby obtaining a relatively smooth frequency response curve and ensuring the low frequency sensitivity of the acoustic output device.

[0112] In some embodiments, the vibration of the elastic mass consisting of the elastic member 1412 and the beam structure 1411 generates a resonant peak in a low frequency range, thereby improving the sensitivity of the acoustic output device in the low frequency range. For example, as shown in FIG. 15 , curves 151 and 152 have a first resonant peak I in the low frequency range (e.g., 300 Hz to 700 Hz). To cause the vibration of the elastic member 1412 and the beam structure 1411 to generate a resonant peak in the low frequency range and thereby improve the sensitivity of the acoustic output device in the low frequency range, in some embodiments, the equivalent elastic modulus of the entire elastic member 1412 corresponding to the elastic ends (e.g., elastic ends 14111 and 14112) may be in the range of 3500 to 4000 N / m. In some embodiments, the equivalent elastic modulus of the entire elastic member 1412 corresponding to the elastic ends may be in the range of 3700 to 3900 N / m.

[0113] FIG. 16A is a schematic diagram of a beam structure according to some embodiments of the present disclosure. The beam structure 1611 shown in FIG. 16A is substantially identical to the beam structure 1411 shown in FIG. 14A . The main difference is that the beam structure 1611 shown in FIG. 16A has free ends (e.g., free ends 16111 and 16112) at both ends thereof, which are connected to a fixed position or structure (e.g., a fixed support base) of an audio output device via an elastic member 1612 installed at the center thereof. For a specific description of the elastic member 1612, please refer to the description of the elastic member 1412 in FIG. 14A . As shown in FIG. 16A , one end of the elastic member 1612 is connected to the center of the beam structure, and the other end is connected to a fixed position or structure of an audio output device. Note that the center of the beam structure 1611 may refer to a certain area range adjacent to the midpoint of its axis.

[0114] In some embodiments, to maintain the structural stability of the beam structure 1611, elastic members 1612 are installed on both sides of the beam structure 1611 perpendicular to its axis. In some embodiments, the connecting lines of the elastic members 1612 on both sides of the beam structure 1611 may be perpendicular to the axis of the beam structure 1611. In some embodiments, the elastic members 1612 on both sides of the beam structure 1611 may be installed symmetrically along a center line perpendicular to the axis of the beam structure 1611 (e.g., center line M shown in FIG. 16A ). In some embodiments, the elastic members 1612 on both sides of the beam structure 1611 may be spaced the same distance from the center line perpendicular to the axis of the beam structure 1611 (e.g., center line M shown in FIG. 16A ).

[0115] FIG. 16B is a schematic diagram of the vibration modes of the beam structure 1611 shown in FIG. 16A. As shown in FIG. 16B, (a) to (e) respectively show vibration mode curves for different vibration modes of the beam structure 1611. (a) shows the initial vibration mode of the beam structure 1611. In this initial vibration mode, the beam structure 1611 begins to vibrate at both ends when it begins to be driven by the piezoelectric element, and both ends of the vibration mode curve sink. As the frequency increases, as shown in (b), the elastic mass formed by the elastic member 1612 and the beam structure 1611 resonates, generating a first resonance peak. In some embodiments, the resonance frequency corresponding to the first resonance peak may be between 400 Hz and 1000 Hz. By way of example only, the frequency response curve of the beam structure 1611 shown in FIG. 17 has a first resonance peak N around 600 Hz. Furthermore, as the frequency increases, both ends of the vibration mode curve shown in (c) rise, and the free ends intersect the horizontal axis. Accordingly, a vibration node occurs at the free end of the beam structure 1611, and the frequency response curve corresponding to the free end may have a resonant dip (e.g., a resonant dip Q shown in FIG. 17). As the frequency further increases, the beam structure 1611 may resonate at its natural resonant frequency, thereby generating a second resonant peak. (d) shows a resonant mode of the beam structure 1611, in which the beam structure 1611 may resonate near a resonant frequency. In some embodiments, the resonant frequency may be between 3300 Hz and 4300 Hz. By way of example only, the frequency response curve of the beam structure 1611 shown in FIG. 17 has a second resonant peak R near 3650 Hz. In this resonant mode, both ends of the vibration mode curve continue to rise, forming two intersections with the horizontal axis near the free end. Accordingly, the beam structure 1611 may have vibration nodes at these two intersections, and the corresponding frequency response curve may have a resonant dip. As the frequency increases further, the beam structure 1611 may resonate at another of its natural resonant frequencies, thereby generating a third resonant peak.(e) shows a resonant mode at another natural resonant frequency of the beam structure 1611, in which the beam structure 1611 can resonate near another resonant frequency. In some embodiments, the resonant frequency may be between 12 kHz and 18 kHz. By way of example only, the frequency response curve of the beam structure 1611 shown in FIG. 17 has a third resonant peak S near 15,000 Hz. In the resonant mode shown in (e), the center and two free ends of the vibration mode curve dip, resulting in four intersections with the horizontal axis. Accordingly, the beam structure 1611 generates vibration nodes at these four intersections, and the corresponding frequency response curve may have resonant dips. As can be seen from FIG. 16B, in the vibration modes shown in (a) to (e), the beam structure 1611 may not always have nodes near the midpoint (e.g., between dashed lines L5 and L6). Accordingly, in the vibration modes (a) to (e), the frequency response curve corresponding to the position close to the elastic end may not always have a resonance dip, and the curve between each resonance peak (e.g., between the first resonance peak N and the second resonance peak R, or between the second resonance peak R and the third resonance peak S) may have a smooth transition. Thus, by selecting the position close to the midpoint as the first position, the curve between the resonance peaks of the audio output device can be smoothly transitioned, further improving the sound quality of the audio output device. In some embodiments, to achieve a smooth transition between the resonance peaks of the audio output device, the ratio of the distance from the first position to one of the elastic ends to the length of the beam structure 1611 may be within a range of 0.3 to 0.7. In some embodiments, the ratio of the distance from the first position to one of the elastic ends to the length of the beam structure 1611 may be within a range of 0.4 to 0.6.

[0116] 17 is a diagram illustrating frequency response curves at different positions of a beam structure according to some embodiments of the present disclosure. As shown in FIG. 17 , curve 171 is a frequency response curve at a free end (e.g., free end 16111 or 16112) of beam structure 1611, and curve 172 is a frequency response curve at a first position of beam structure 1611, where the ratio of the distance from the first position to one of the free ends (e.g., free end 16111) to the length of beam structure 1611 is 0.45. As can be seen from curves 171 and 172, when the output position is at the first position, the frequency response curve of the acoustic output device has no or small resonance dips within a frequency range of 500 Hz to 15,000 Hz, and there are smooth transitions between each resonance peak (e.g., between first resonance peak N and second resonance peak R, and between second resonance peak R and third resonance peak S), resulting in a better frequency response. As a result, the first position connected to the mass element in the beam structure 1611 can be close to the midpoint of the beam structure 1611, and the ratio of the distance from the first position to one of the elastic ends to the length of the beam structure 1611 is in the range of 0.4 to 0.6, thereby obtaining a relatively smooth frequency response curve and improving the sound quality of the acoustic output device.

[0117] 18 is a partial schematic diagram of an acoustic output device according to some embodiments of the present disclosure. As shown in FIG. 18 , the acoustic output device includes a beam structure 1811 and a second beam structure 1821. In some embodiments, the beam structure 1811 may be the same as or similar to the second beam structure 1821. The beam structure 1811 and the second beam structure 1821 may be similar to the beam structure 211 shown in FIG. 2 , and more information regarding the beam structure 1811 and the second beam structure 1821 can be found in FIG. 2 .

[0118] 18, beam structure 1811 and second beam structure 1821 have one fixed end and the other connected to each other via connecting member 1830. In some embodiments, connecting member 1830 may be a resilient connecting member. In some embodiments, the resilient connecting member may be a resilient structure.

[0119] FIG. 19 is a schematic diagram of an acoustic output device according to some embodiments of the present disclosure. As shown in FIG. 19 , the acoustic output device may include two or more vibration elements, each of which includes a beam structure 1911, with the beam structure 1911 including a fixed end 19111 and a free end 19112. The beam structures 1911 may be spaced apart around a periphery of a mass element 1920, with the mass elements 1920 connected to first locations 19113 of the beam structures 1911, respectively. In some embodiments, the mass elements 1920 may include a diaphragm, a membrane, or the like, such that the acoustic output device can output vibrations through the mass elements 1920. The beam structure 1911 is similar to the beam structure 211 shown in FIG. 2 , and more information regarding the beam structure 1911 may be found in FIG. 2 .

[0120] In some embodiments, the beam structures 1911 may be symmetrically distributed around the periphery of the mass element 1920 along the midpoint of the mass element 1920. In some embodiments, the beam structures 1911 may be evenly spaced around the periphery of the mass element 1920. In some embodiments, the ratio of the distance between the first position of the beam structures 1911 connected to the mass element 1920 and the fixed end 19111 of the beam structure 1911 to the length of the beam structure may be equal. In some embodiments, by determining the first position 19113 based on the description of other embodiments in this specification (e.g., FIG. 3 ), it is possible to cancel peaks and dips in the frequency response curve of the mass element 1920 (or the acoustic output device), obtain a smooth curve over a wide frequency range, and further improve the sound quality of the acoustic output device. In some embodiments, to achieve cancellation of the first resonance dip and the second resonance peak in the frequency response curve of the mass element 1920, to provide a smooth curve over a wide frequency range between the first resonance peak and the second resonance peak of the audio output device, and to further improve the sound quality of the audio output device, the ratio of the distance between the first position of each beam structure 1911 connected to the mass element 1920 and the fixed end 19111 of the beam structure 1911 to the length of the beam structure may be in the range of 0.75 to 0.95. In some embodiments, the ratio of the distance between the first position of each beam structure 1911 connected to the mass element 1920 and the fixed end 19111 of the beam structure 1911 to the length of the beam structure may be in the range of 0.8 to 0.85. In some embodiments, in order to achieve cancellation of the first resonance dip and the third resonance peak in the frequency response curve of the mass element 1920, and to have a smooth curve with a wide frequency band between the second resonance peak and the third resonance peak of the audio output device, and further improve the sound quality of the audio output device, the ratio of the distance between the first position of each beam structure 1911 connected to the mass element 1920 and the fixed end 19111 of the beam structure 1911 to the length of the beam structure may be in the range of 0.45 to 0.6.In some embodiments, the ratio of the distance between the first position in each beam structure 1911 connected to the mass element 1920 and the fixed end 19111 of the beam structure 1911 to the length of the beam structure may be in the range of 0.5 to 0.55.

[0121] 2 to 19 are merely illustrative and not limiting. The achievable beneficial effects vary depending on the embodiment, and in different embodiments, the achievable beneficial effects may be any one or a combination of more than one of the above, or any other achievable beneficial effects.

[0122] Although the basic concepts have been described above, it will be apparent to those skilled in the art that the above detailed disclosure is merely provided as an example and is not intended to limit the present application. Although not expressly described herein, those skilled in the art may make various changes, improvements, and modifications to the present application. These changes, improvements, and modifications are intended to be suggested by the present application and therefore remain within the spirit and scope of the exemplary embodiments of the present application.

[0123] Furthermore, certain terms are used herein to describe embodiments of the present application. For example, "one embodiment," "one embodiment," and / or "some embodiments" refer to particular features, structures, or characteristics associated with at least one embodiment of the present application. Therefore, it is emphasized and understood that references to "one embodiment" or "one embodiment" or "one alternative embodiment" more than once in various parts of this specification do not necessarily all refer to the same embodiment. Furthermore, particular features, structures, or characteristics of one or more embodiments of the present application may be combined as appropriate.

[0124] Furthermore, unless expressly stated in the claims, the enumerated order, use of alphanumeric characters, or other designations of processing elements or sequences described herein do not limit the order of procedures and methods herein. While the above disclosure has set forth through various examples what are presently believed to be various useful embodiments of the invention, it should be understood that such details are merely illustrative, and that the appended claims are not limited to the disclosed embodiments, but rather are intended to cover all modifications and equivalent combinations within the spirit and scope of the embodiments herein. For example, the system assembly described above may be implemented by a hardware device, or may be implemented as a software-only solution, e.g., by installing the described system on an existing server or mobile device.

[0125] Similarly, in the foregoing description of embodiments of the present application, various features may be grouped together in a single embodiment, drawing, or description for the purpose of simplifying the application and facilitating an understanding of one or more embodiments of the present invention. However, this method of disclosure should not be interpreted as reflecting an intention that the claimed subject matter requires more features than are recited in each claim. In fact, an embodiment may include fewer than all features of a single embodiment disclosed above.

[0126] In some embodiments, numbers are used to describe the number of components and attributes, and the numbers describing such embodiments may be understood to be modified in some instances by the modifiers "about," "approximately," or "substantially." Unless otherwise specified, "about," "approximately," or "substantially" indicates that the numbers are subject to a ±20% variation. Accordingly, in some embodiments, all numerical parameters used in the specification and claims are approximations that may vary depending on the characteristics required for a particular embodiment. In some embodiments, numerical parameters should be used with the stated number of significant digits and ordinary rounding techniques should be applied. While in some embodiments, the numerical ranges and parameters used to determine ranges are approximations, in specific embodiments, such numerical values ​​are set as precisely as possible.

[0127] All patents, patent applications, published patent applications, and other materials, such as papers, books, specifications, publications, and documents, referenced in this application are incorporated herein by reference in their entirety, except for prosecution history documents that are inconsistent with or inconsistent with the content of this application and documents that may have a limiting effect on the broadest scope of the claims of this application (now or later related to this application). Furthermore, if a statement, definition, and / or term usage in the accompanying materials of this application is inconsistent with or inconsistent with the content set forth in this application, the statement, definition, and / or term usage in this application shall control.

[0128] Finally, it is to be understood that the embodiments herein are merely illustrative of the principles of the present embodiments. Other variations may be within the scope of the present application. Thus, by way of example, but not of limitation, alternative configurations of the present embodiments may be considered consistent with the teachings of the present application. Accordingly, the present embodiments are not limited to the embodiments expressly introduced and described herein. [Explanation of symbols]

[0129] 100 Sound output device 110 vibration element 120 mass elements 1112 Piezoelectric layer 211 Beam Structure 212 Fixed support base 2111 Fixed end 2112 Free end 2113 Piezoelectric layer 2114 base layer 411 Beam Structure 430 Second Mass Element 4111 Fixed end 4112 Free end 711 Beam Structure 7111 Fixed end 7112 Pivot end 713 Pivot Pin 7141 Pivot hole 911 Beam Structure 9111 Fixed end 9112 Elastic end

Claims

1. An audio output device, a vibration element including a beam structure extending along a longitudinal direction; The beam structure comprises: a piezoelectric layer that deforms in response to an electric signal to vibrate the vibration element, and a mass element connected to a first position of the beam structure, the mass element vibrating in a direction perpendicular to the longitudinal direction due to vibration of the vibration element, wherein a ratio of a distance from the first position to one end of the beam structure along the longitudinal direction of the beam structure to a length of the beam structure is in a range of 0.3 to 0.95; the beam structure includes a fixed end and a free end, the acoustic output device further includes a second mass element connected to the free end, and a ratio of a mass of the second mass element to a mass of the beam structure is in a range of 0.2 to 1.

2. 2. The acoustic output device of claim 1, wherein the vibration of the mass element has a first resonant peak and a second resonant peak within a range of 50 Hz to 10,000 Hz, and the amplitude difference between the lowest point of the frequency response between the first resonant peak and the second resonant peak and the first resonant peak or the second resonant peak is less than 40 dB.

3. 2. The acoustic output device according to claim 1, wherein a ratio of the distance from the first position to the fixed end to the length of the beam structure is in a range of 0.7 to 0.

95.

4. 3. The acoustic output device of claim 2, wherein the vibration of the mass element has a third resonant peak, and the amplitude difference between the lowest point of the frequency response between the second resonant peak and the third resonant peak and the second resonant peak or the third resonant peak is less than 30 dB.

5. The acoustic output device according to claim 4 , wherein a ratio of the frequency of the third resonance peak to the frequency of the second resonance peak is greater than four.

6. 6. The acoustic output device according to claim 5, wherein a ratio of a distance from the first position to the fixed end to a length of the beam structure is in a range of 0.45 to 0.

6.

7. 2. The acoustic output device of claim 1, wherein the number of vibration elements is two or more, the mass element is connected to a first position of a beam structure of each of the two or more vibration elements, and a ratio of a distance between the first position of each beam structure and a fixed end of the beam structure to a length of the beam structure is within a range of 0.7 to 0.

95.

8. An acoustic output device as described in claim 1, characterized in that the ratio of the distance from the first position to the fixed end to the length of the beam structure gradually increases as the ratio of the mass of the second mass element to the mass of the beam structure increases.

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