CN116939444A - Acoustic output device - Google Patents

Acoustic output device Download PDF

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Publication number
CN116939444A
CN116939444A CN202210360069.XA CN202210360069A CN116939444A CN 116939444 A CN116939444 A CN 116939444A CN 202210360069 A CN202210360069 A CN 202210360069A CN 116939444 A CN116939444 A CN 116939444A
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CN
China
Prior art keywords
piezoelectric element
output device
vibration
acoustic output
piezoelectric
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CN202210360069.XA
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Chinese (zh)
Inventor
朱光远
张磊
齐心
王庆依
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Shenzhen Voxtech Co Ltd
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Shenzhen Voxtech Co Ltd
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Priority to CN202210360069.XA priority Critical patent/CN116939444A/en
Priority to TW112110919A priority patent/TWI843498B/en
Publication of CN116939444A publication Critical patent/CN116939444A/en
Pending legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00—Piezoelectric transducers; Electrostrictive transducers

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Piezo-Electric Transducers For Audible Bands (AREA)
  • Details Of Audible-Bandwidth Transducers (AREA)

Abstract

The embodiment of the specification provides an acoustic output device, which comprises a first vibration element, a second vibration element and a piezoelectric element. The first vibration element is physically connected to the first location of the piezoelectric element, and the second vibration element is connected to the second location of the piezoelectric element at least through an elastic element. The piezoelectric element vibrates the first vibration element and the second vibration element in response to an electric signal, and the vibration generates two resonance peaks in the audible range of human ears.

Description

Acoustic output device
Technical Field
The present disclosure relates to the field of acoustic technologies, and in particular, to an acoustic output device.
Background
The piezoelectric acoustic output device utilizes the inverse piezoelectric effect of piezoelectric materials to generate vibration to radiate sound waves outwards, and has the advantages of high electromechanical transduction efficiency, low energy consumption, small volume, high integration level and the like compared with a transmission electrodynamic loudspeaker. With the trend of miniaturization and integration of devices nowadays, piezoelectric acoustic output devices have extremely broad prospects and future. However, the piezoelectric acoustic output device has problems such as poor low-frequency response and a large number of vibration modes in the audible region of the human ear (for example, 20Hz to 20 kHz), and thus cannot form a relatively flat frequency response curve in the audible region, resulting in a problem of poor sound quality.
It is desirable to provide an acoustic output device that enhances the low frequency response of a piezoelectric acoustic output device while forming a flatter frequency response curve in the audible region that enhances the acoustic quality of the acoustic output device.
Disclosure of Invention
Embodiments of the present disclosure may provide an acoustic output device including a first vibration element physically connected to a first location of a piezoelectric element, a second vibration element connected to a second location of the piezoelectric element at least through an elastic element, and a piezoelectric element responsive to an electrical signal to vibrate the first vibration element and the second vibration element, the vibration producing two resonance peaks in an audible range of a human ear.
Additional features of the application will be set forth in part in the description which follows. Additional features of the application will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following description and the accompanying drawings or may be learned from production or operation of the embodiments. The features of the present application can be implemented and obtained by practicing or using the various aspects of the methods, tools, and combinations set forth in the following detailed examples.
Drawings
The present specification will be further elucidated by way of example embodiments, which will be described in detail by means of the accompanying drawings. The embodiments are not limiting, in which like numerals represent like structures, wherein:
FIG. 1 is a block diagram of an exemplary acoustic output device shown in accordance with some embodiments of the present description;
FIG. 2 is a schematic diagram of an exemplary acoustic output device shown in accordance with some embodiments of the present application;
fig. 3 is a piezoelectric cantilever Liang Moxing shown in accordance with some embodiments of the present description;
FIG. 4 is a graph of output frequency response from a sprung mass end to a mass end of an exemplary acoustic output device according to some embodiments of the present description;
FIG. 5 is a graph comparing the frequency response of the piezoelectric cantilever free end output with the frequency response of an acoustic output device comprising a single beam structure of the same beam length, according to some embodiments of the present disclosure;
FIG. 6 is a plot of the frequency response of an acoustic output device including a first vibrating element of different masses shown in accordance with some embodiments of the present description;
FIG. 7 is a schematic diagram of an acoustic output device according to some embodiments of the present disclosure;
FIG. 8 is a schematic diagram of an acoustic output device according to some embodiments of the present disclosure;
FIG. 9 is a plot of frequency response of vibration signals from an elastic mass terminal of an acoustic output device having a single beam structure, a double beam structure, and a four beam structure, respectively, according to some embodiments of the present disclosure;
FIG. 10 is a schematic diagram of an acoustic output device according to some embodiments of the present disclosure;
FIG. 11 is an output frequency response plot of an exemplary acoustic output device shown in accordance with some embodiments of the present description;
FIG. 12 is a plot of the frequency response of an acoustic output device for different excitation signal phase differences;
FIG. 13 is a plot of the frequency response of an acoustic output device for different excitation signal phase differences;
FIG. 14 is a schematic diagram of an exemplary acoustic output device shown in accordance with some embodiments of the present disclosure;
FIG. 15 is a graph of output frequency response of an acoustic output device of different construction shown in accordance with some embodiments of the present disclosure;
FIG. 16 is a schematic diagram of an exemplary acoustic output device shown in accordance with some embodiments of the present disclosure;
FIG. 17 is a schematic diagram of an exemplary acoustic output device shown in accordance with some embodiments of the present disclosure;
Fig. 18 is a graph of frequency response of vibration signals output from the sprung mass end of the acoustic output device having the single beam structure, the double beam structure, and the four beam structure, respectively, according to some embodiments of the present description.
Detailed Description
In order to more clearly illustrate the technical solutions of the embodiments of the present specification, the drawings used in the description of the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some examples or embodiments of the present specification, and it is possible for those of ordinary skill in the art to apply the present specification to other similar situations according to the drawings without inventive effort. It should be understood that these exemplary embodiments are presented merely to enable one skilled in the relevant art to better understand and practice the present description, and are not intended to limit the scope of the present description in any way. Unless otherwise apparent from the context of the language or otherwise specified, like reference numerals in the figures refer to like structures or operations.
It will be appreciated that "system," "apparatus," "unit" and/or "module" as used herein is one method for distinguishing between different components, elements, parts, portions or assemblies of different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.
As used in this specification and the claims, the terms "a," "an," "the," and/or "the" are not specific to a singular, but may include a plurality, unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that the steps and elements are explicitly identified, and they do not constitute an exclusive list, as other steps or elements may be included in a method or apparatus. The term "based on" is based at least in part on. The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment".
In the description of the present specification, it should be understood that the terms "first," "second," "third," "fourth," and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "first", "second", "third", and "fourth" may explicitly or implicitly include at least one such feature. In the description of the present specification, the meaning of "plurality" means at least two, for example, two, three, etc., unless explicitly defined otherwise.
In this specification, unless clearly indicated and limited otherwise, the terms "connected," "fixed," and the like are to be construed broadly. For example, the term "coupled" may mean either a fixed connection, a removable connection, or an integral body; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in this specification will be understood by those of ordinary skill in the art in view of the specific circumstances.
The acoustic output device provided by the embodiment of the application can utilize the inverse piezoelectric effect to generate vibration through the piezoelectric element so as to output sound. In general, the piezoelectric element may adopt two modes of operation d33 and d 31. In the d33 operation mode, the vibration direction (also referred to as the displacement output direction) of the piezoelectric element is the same as the electrical direction (also referred to as the polarization direction), the resonant frequency is high, the output amplitude is small, and the low-frequency response is poor. In the d31 operation mode, the vibration direction of the piezoelectric element is perpendicular to the electrical direction. In the d31 mode of operation, although the output amplitude is also significantly increased by increasing the length of the piezoelectric element to provide a low frequency peak of sufficiently low frequency, in this case the piezoelectric element has more vibrational modes in the audible domain (e.g. 20Hz-20 kHz) and appears as a peak Gu Jiaoduo of the frequency response, so the acoustic output device (or piezoelectric speaker) still has poor sound quality.
To solve the problem of poor low-frequency response and more modes in the audible domain of the piezoelectric speaker, the acoustic output device provided by the embodiments of the present disclosure may include a first vibration element, a second vibration element, and a piezoelectric element. Wherein the first vibration element is physically connected to the first position of the piezoelectric element, and the second vibration element is connected to the second position of the piezoelectric element at least through the elastic element. The piezoelectric element may vibrate the first vibration element and the second vibration element in response to the electrical signal. The vibration can produce two resonance peaks (e.g., a first resonance peak and a second resonance peak) in the audible range of the human ear.
According to the embodiments of the present specification, the low frequency response of the piezoelectric element can be enhanced by generating the first resonance peak of the two resonance peaks, which has a lower frequency (e.g., 50Hz-2000 Hz), by using the resonance of the second vibration element and the elastic element. In addition, since the resonance of the piezoelectric element and the first vibration element can generate a second resonance peak with a higher frequency (for example, 1 kHz-10 kHz) of the two resonance peaks, when the sound signal is output through the vibration of the second vibration element (for example, the second vibration element is attached to the face of the user to transmit bone conduction sound to the user, or the second vibration element pushes air to generate air conduction sound radiated to the ear of the user), the frequency response curve between the first resonance peak and the second resonance peak can be relatively flat, so that the sound quality of the acoustic output device is improved. In some embodiments, when the sound signal is vibrationally output by the first vibrating element (e.g., the first vibrating element is in contact with the face of the user to deliver bone conduction sound to the user, or the first vibrating element pushes air to generate air conduction sound radiating to the ear of the user), the sensitivity of the acoustic output device at a medium-high frequency band (e.g., 500Hz-10 kHz) may be improved, thereby facilitating application of the acoustic output device in a special scenario.
The following describes in detail an acoustic output device provided by an embodiment of the present application with reference to the accompanying drawings.
Fig. 1 is a block diagram of an exemplary acoustic output device shown in accordance with some embodiments of the present description. In some embodiments, acoustic output device 100 may be a bone conduction acoustic output device, an air conduction acoustic output device, or a bone-air conduction combined acoustic output device. In some embodiments, the acoustic output device 100 may include a sound, an earphone, glasses, a hearing aid, an augmented Reality (Augmented Reality, AR) device, a Virtual Reality (VR) device, etc., or other devices with audio playing function (e.g., a cell phone, a computer, etc.). In some embodiments, the acoustic output device 100 may be an open acoustic output device. As shown in fig. 1, the acoustic output device 100 may include a first vibration element 110, a second vibration element 120, a piezoelectric element 130, and an elastic element 140.
The first vibration element 110 and the second vibration element 120 may each be a mass having a certain mass. In some embodiments, the first vibration element 110 and/or the second vibration element 120 may include a vibrating plate, a vibrating diaphragm, or the like, such that the acoustic output device 100 outputs vibrations through the first vibration element 110 and/or the second vibration element 120. In some embodiments, the mass may include, but is not limited to, metals (e.g., copper, iron, magnesium, aluminum, tungsten, etc.), alloys (aluminum alloys, titanium alloys, tungsten alloys, etc.), polymeric materials (e.g., polytetrafluoroethylene, silicone rubber, etc.), and the like. In some embodiments, the material of the first vibration element 110 and the material of the second vibration element 120 may be the same or different. In some embodiments, the mass of the first vibratory element 110 may be the same as or different from the mass of the second vibratory element 120.
The first vibration element 110 may be physically coupled (e.g., glued, snapped, screwed, welded, etc.) to the first location of the piezoelectric element 130, and the second vibration element 120 may be coupled to the second location of the piezoelectric element 130 via at least the elastic element 140. In some embodiments, the first location may be the same as or different from the second location. For example, when the piezoelectric element 130 has a beam-like structure, both the first position and the second position may be located at the end of the piezoelectric element 130 in the direction in which the length of the beam-like structure extends. As another example, as shown in fig. 2, the first position and the second position may be located at both ends of the beam-like structure of the piezoelectric element 130 in the length extending direction, respectively. As another example, as shown in fig. 7, the first position may be located at the center of the piezoelectric element 130, and the second position may be located at either end of the length extension direction of the beam-like structure of the piezoelectric element 130. In the present specification, the longitudinal extension direction of the beam-like structure of the piezoelectric element 130 may refer to a direction in which the characteristic dimension of the beam-like structure in the extension direction is greater than the characteristic dimension of the beam-like structure in any other direction by a factor of 1 or more. In some embodiments, the beam-like structure may include a straight beam-like structure, a curved beam-like structure, and the like. In the present specification, a linear beam-like structure will be described as an example, which is not intended to limit the scope of the present specification. In some embodiments, the elastic element 140 may be directly connected to the second position of the piezoelectric element 130. In some embodiments, the acoustic output device 100 may include a connector (not shown). The second vibration element 120 and the elastic element 140 may be connected to the second position of the piezoelectric element 130 by a connection. For example, as shown in fig. 7, the second vibration element 120 and the elastic element 140 may be connected to an end portion (i.e., the second position) of the piezoelectric element 130 by a connection 190.
The first and second vibration elements 110 and 120 may generate vibrations in response to the vibrations of the piezoelectric element 130, respectively. Specifically, the piezoelectric element 130 may directly transmit the vibration to the first vibration element 110, and the vibration of the piezoelectric element 130 may be transmitted to the second vibration element 120 through the elastic element 140. In the present embodiment, the first vibration element 110 directly connected to the piezoelectric element 130 may be referred to as a mass end, and the second vibration element 120 connected to the piezoelectric element 130 through the elastic element 140 may be referred to as an elastic mass end.
In some embodiments, the material of the elastic element 140 may be any material capable of transmitting vibration energy. For example, the material of the elastic element 140 may be silica gel, foam, plastic, rubber, metal, etc., or any combination thereof. In some embodiments, the elastic element 140 may be a component having good elasticity (i.e., being subject to elastic deformation). For example, the elastic element 140 may include a spring (e.g., an air spring, a mechanical spring, an electromagnetic spring, etc.), a vibration-transmitting sheet, a spring plate, a substrate, etc., or any combination thereof. In some embodiments, the number of elastic elements 140 may be one or more. For example, as shown in fig. 2, the second vibration element 120 may be connected to the piezoelectric element 130 through an elastic element 140. As another example, as shown in fig. 7, the second vibration element 120 may be connected to the piezoelectric element 130 through 4 elastic elements 140. In some embodiments, the shape of the resilient element 140 may be a ring, a rod-like structure, or the like. In some embodiments, the elastic elements 140 may be axisymmetrically distributed with respect to the axis of the center of the piezoelectric element 130.
The piezoelectric element 130 may be an electric energy conversion device capable of converting electric energy into mechanical energy using an inverse piezoelectric effect. In some embodiments, the piezoelectric element 130 may be composed of a material having a piezoelectric effect, such as piezoelectric ceramics, piezoelectric quartz, piezoelectric crystals, piezoelectric polymers, or the like. In some embodiments, the piezoelectric element 130 may be in a shape of a sheet, a ring, a prism, a cuboid, a column, a sphere, or the like, or any combination thereof, and may be in other irregular shapes. In some embodiments, the piezoelectric element 130 may include a beam-like structure (as shown in fig. 2, 7, 16, etc.). As an example, it may comprise two layers of piezoelectric sheets and a substrate, the two layers of piezoelectric sheets being attached to opposite sides of the substrate, respectively. The substrate may vibrate according to the stretching of the two layers of piezoelectric sheets along the length extension direction of the beam-like structure (e.g., vibrate in a direction perpendicular to the substrate surface). For more description of beam-like structures, see fig. 2 and its description.
In some embodiments, when the piezoelectric element 130 includes a beam-like structure, the first and second positions may be located at two ends of the piezoelectric element 130, respectively (as shown in fig. 2). In some embodiments, when the piezoelectric element 130 includes a beam-like structure, the first position may be located at a center of a length extension direction of the beam-like structure. The second location may be at an end of the beam-like structure in the lengthwise extension (as shown in fig. 7). In some embodiments, when the piezoelectric element 130 includes a beam-like structure, the first vibration element 110 may include two sub-vibration elements, wherein the two sub-vibration elements may be respectively connected at both ends (i.e., first positions) of the length extension direction of the piezoelectric element 130 (as shown in fig. 17). The second position may be located at the center of the length extension direction of the piezoelectric element 130.
The piezoelectric element 130 may be deformed by a driving voltage (or an excitation signal) to generate vibration. The vibration may vibrate the first vibration element 110 and the second vibration element 120, thereby generating two resonance peaks in the audible range of the human ear (e.g., 20Hz-20 kHz). Specifically, the resonance of the second vibration element 120 and the elastic element 140 may generate a first resonance peak (e.g., a resonance peak in the virtual coil X in fig. 4) of the two resonance peaks having a lower frequency (e.g., 20Hz to 2000 Hz), and the resonance of the piezoelectric element 130 and the first vibration element 110 may generate a second resonance peak (e.g., a resonance peak in the virtual coil Y in fig. 4) of the two resonance peaks having a higher frequency (e.g., 1kHz to 10 kHz). The frequency corresponding to the second resonance peak (which may also be referred to as the second resonance frequency) may be higher than the frequency corresponding to the first resonance peak (which may also be referred to as the first resonance frequency).
In some embodiments, the frequency range of the first resonant frequency corresponding to the first resonant peak may be adjusted by adjusting the mass of the second vibration element 120 and/or the elastic coefficient of the elastic element 140. In some embodiments, the first resonant frequency may have a frequency range of 50Hz-1500Hz. In some embodiments, the first resonant frequency may have a frequency range of 100 Hz-1000Hz. In some embodiments, the first resonant frequency may have a frequency range of 150Hz-500Hz.
In some embodiments, the frequency range of the second resonant frequency corresponding to the second resonant peak may be adjusted by adjusting the performance parameter of the piezoelectric element 130. In some embodiments, the performance parameters of the piezoelectric element 130 may include geometric parameters, material parameters, and the like. Exemplary geometric parameters may include thickness, length, etc. Exemplary material parameters may include modulus of elasticity, density, and the like. In some embodiments, the second resonant frequency may be a natural frequency of the piezoelectric element 130. In some embodiments, the second resonant frequency may have a frequency in the range of 1kHz-10kHz. In some embodiments, the second resonant frequency may have a frequency in the range of 1kHz-8kHz. In some embodiments, the second resonant frequency may have a frequency range of 2 kHz-5kHz. In some embodiments, the second resonant frequency may have a frequency range of 3kHz-4kHz.
In some embodiments, damping may be added to one or more elements of the acoustic output device 100 to make the frequency response curve of the output of the acoustic output device 100 smoother. For example, the elastic member 140 may be prepared using a material having a large damping effect (e.g., silicone, rubber, foam, etc.). For another example, a damping material may be coated on the piezoelectric element 130. For another example, a damping material or electromagnetic damping may be coated on the first vibration element 110 and/or the second vibration element 120.
In some embodiments, vibrations of the piezoelectric element 130 (or the acoustic output device 100) may be transmitted to the user in a bone-conduction manner through the first vibration element 110 and/or the second vibration element 120. For example, the second vibration element 120 may be in direct contact with the skin of the user's head, and the vibration of the piezoelectric element 130 is transmitted to the bones and/or muscles of the user's face through the second vibration element 120, and finally to the user's ear. For another example, the second vibration element 120 may not be in direct contact with the human body, and the vibration of the piezoelectric element 130 may be transmitted to the housing of the acoustic output device through the second vibration element 120, and then transmitted to the bones and/or muscles of the user's face through the housing, and finally transmitted to the user's ear. In some embodiments, the vibration of the piezoelectric element 130 may also be transmitted to the user in an air-conductive manner through the first vibration element 110 and/or the second vibration element 120. For example, the second vibration element 120 may directly vibrate its surrounding air, thereby being transferred to the user's ear through the air. For another example, the second vibration element 120 may be further connected to the diaphragm, and the vibration of the second vibration element 120 may be transferred to the diaphragm, and then the diaphragm drives the air to vibrate, so that the vibration is transferred to the ear of the user through the air.
In some embodiments, the acoustic output device 100 may also include a second piezoelectric element 150. In some embodiments, both the piezoelectric element 130 (which may also be referred to as a first piezoelectric element 130) and the second piezoelectric element 150 may comprise beam-like structures. The length of the beam-like structure of the second piezoelectric element 150 (i.e., the dimension along the length extension direction of the beam-like structure, which may also be referred to as the second length) may be shorter than the length of the beam-like structure of the first piezoelectric element 130 (which may also be referred to as the first length). In some embodiments, the second piezoelectric element 150 may be directly connected to the second vibration element 120. For example, the second piezoelectric element 150 may be directly attached to the second vibration element 120. The second piezoelectric element 150 may receive the vibration of the second vibration element 120. The second piezoelectric element 150 resonates to generate a third resonance peak having a frequency higher than the first resonance peak and the second resonance peak. In some embodiments, the frequency range of the third resonant frequency corresponding to the third resonant peak may be adjusted by adjusting a performance parameter (e.g., a geometric parameter, a material parameter, etc.) of the second piezoelectric element 150. In some embodiments, the third resonant frequency may have a frequency in the range of 10kHz to 40kHz. Further description of the second piezoelectric element 150 may be found in fig. 10, and will not be repeated here.
In some embodiments, the acoustic output device 100 may further include a third piezoelectric element 160. The third piezoelectric element 160 may generate vibration in response to the electric signal and transmit the vibration to the second piezoelectric element 150. In some embodiments, the vibration of the third piezoelectric element 160 may be transferred to the second piezoelectric element 150 through the third vibration element. In some embodiments, the third vibration element may be coupled to the third piezoelectric element 160 via at least a second elastic element. The third piezoelectric element 160 resonates to generate a fourth resonance peak having a frequency lower than the third resonance peak. Further description of the third piezoelectric element 160 may be found in fig. 14, and will not be repeated here.
In some embodiments, the acoustic output device 100 may also include a housing structure 170. The housing structure 170 may be configured to carry other components of the acoustic output device 100 (e.g., the first vibration element 110, the second vibration element 120, the piezoelectric element 130, the elastic element 140, etc.). In some embodiments, the housing structure 170 may be an enclosed or semi-enclosed structure that is hollow inside, and other components of the acoustic output device 100 are located within or on the housing structure. In some embodiments, the shape of the housing structure may be a regular or irregular shaped solid structure such as a cuboid, cylinder, truncated cone, etc. The housing structure may be located in a position near the user's ear when the acoustic output device 100 is worn by the user. For example, the housing structure may be located on the peripheral side (e.g., front or back) of the user's pinna. For another example, the housing structure may be positioned over the user's ear but not occlude or cover the user's ear canal. In some embodiments, the acoustic output device 100 may be a bone conduction earphone, and at least one side of the housing structure may be in contact with the skin of the user. An acoustic driver assembly (e.g., a combination of the piezoelectric element 130, the first vibration element 110, the elastic element 140, and the second vibration element 120) in the bone conduction headphones converts the audio signal into mechanical vibrations that can be transmitted through the housing structure and the user's bones to the user's auditory nerve. In some embodiments, the acoustic output device 100 may be an air-conduction earphone, with or without at least one side of the housing structure in contact with the skin of the user. The side wall of the shell structure comprises at least one sound guide hole, and an acoustic driver assembly in the air guide earphone converts the audio signal into air guide sound, and the air guide sound can radiate towards the direction of the ears of the user through the sound guide hole.
In some embodiments, the acoustic output device 100 may include a fixation structure 180. The securing structure 180 may be configured to secure the acoustic output device 100 near the user's ear. In some embodiments, the securing structure 180 may be physically connected (e.g., glued, snapped, threaded, welded, etc.) with the housing structure 170 of the acoustic output device 100. In some embodiments, the housing structure 170 of the acoustic output device 100 may be part of the stationary structure 180. In some embodiments, the securing structure 180 may include an ear hook, a back hook, an elastic band, a glasses leg, etc., so that the acoustic output device 100 may be better secured in place near the user's ear, preventing the user from falling out during use. For example, the fixation structure 180 may be an ear hook that may be configured to be worn around an ear region. In some embodiments, the ear hook may be a continuous hook and may be elastically stretched to fit over the user's ear, while the ear hook may also apply pressure to the user's pinna such that acoustic output device 100 is securely fixed to a particular location on the user's ear or head. In some embodiments, the earhook may be a discontinuous ribbon. For example, the earhook may include a rigid portion and a flexible portion. The rigid portion may be made of a rigid material (e.g., plastic or metal) and may be secured by way of a physical connection (e.g., snap fit, threaded connection, etc.) with the housing structure 170 of the acoustic output device 100. The flexible portion may be made of an elastic material (e.g., cloth, composite, or/and neoprene). For another example, the fixation structure 180 may be a neck strap configured to be worn around the neck/shoulder region. For another example, the securing structure 180 may be a temple that is mounted to a user's ear as part of eyeglasses.
It should be noted that the above description with respect to FIG. 1 is provided for illustrative purposes only and is not intended to limit the scope of the present application. Many variations and modifications will be apparent to those of ordinary skill in the art in light of the teaching of this application. For example, in some embodiments, acoustic output device 100 may also include one or more components (e.g., a signal transceiver, an interaction module, a battery, etc.). In some embodiments, one or more components of acoustic output device 100 may be replaced with other elements that perform similar functions. For example, the acoustic output device 100 may not include the fixed structure 180, and the housing structure 170 or a portion thereof may be a housing structure having a shape that is adapted to the human ear (e.g., circular, oval, polygonal (regular or irregular), U-shaped, V-shaped, semi-circular) so that the housing structure may hang in proximity to the user's ear. Such changes and modifications may be made without departing from the scope of the present application.
Fig. 2 is a schematic diagram of an exemplary acoustic output device shown in accordance with some embodiments of the present application. Fig. 3 is a piezoelectric cantilever Liang Moxing shown in accordance with some embodiments of the present description. As shown in fig. 2, the acoustic output device 200 may include a first vibration element 110, a second vibration element 120, a piezoelectric element 130, and an elastic element 140. The piezoelectric element 130 may include a beam-like structure. The first vibration element 110 is connected to one end (i.e., a first position) of the piezoelectric element 130, and the second vibration element 120 is connected to the other end (i.e., a second position) of the piezoelectric element 130 through the elastic element 140. The piezoelectric element 130 may drive the first vibration element 110 and the second vibration element 120 to vibrate. This vibration may produce two resonance peaks in the audible range of the human ear (as shown in fig. 4). It should be noted that when the piezoelectric element 130 vibrates, the amplitude of the end portion of the beam-like structure along the length extending direction is larger, and the sensitivity is higher, so that the first position and the second position are disposed at the end portion of the beam-like structure along the length extending direction, and the sensitivity of the frequency response of the acoustic output device 200 can be improved. In some embodiments, the acoustic output device 200 may further include a securing structure (not shown) that may be configured to secure the acoustic output device 200 near the user's ear such that the piezoelectric element 130 and the first vibration element 110 (and/or the second vibration element 120) form a cantilever structure. In the present application, a structure in which one end of a piezoelectric element having a beam-like structure in a length extending direction is connected to one vibration element and the other end is connected to the other vibration element through an elastic element may be simply referred to as a single beam structure.
In some embodiments, piezoelectric element 130 may include two piezoelectric sheets (i.e., piezoelectric sheet 132 and piezoelectric sheet 134) and substrate 136. The substrate 136 may be configured as a carrier carrying the components and as an element that deforms in response to vibration. In some embodiments, the material of the substrate 136 may include one or more combinations of metals (e.g., copper clad, steel, etc.), phenolic resins, crosslinked polystyrene, and the like. In some embodiments, the shape of the substrate 136 may be determined according to the shape of the piezoelectric element 130. For example, if the piezoelectric element 130 includes a beam-like structure, the substrate 136 may be correspondingly disposed in an elongated shape. For another example, if the piezoelectric element 130 is a piezoelectric film, the substrate 136 may be provided in a plate shape or a sheet shape.
Piezoelectric patch 132 and piezoelectric patch 134 may be components configured to provide a piezoelectric effect and/or an inverse piezoelectric effect. In some embodiments, the piezoelectric sheet may cover one or more surfaces of the substrate 136, and deform under the action of the driving voltage to drive the substrate 136 to deform, so as to realize the output vibration of the piezoelectric element 130. For example, in the thickness direction of the piezoelectric element 130 (as indicated by arrow BB 'in fig. 2), the piezoelectric sheets 132 and 134 are attached to opposite sides of the substrate 136, respectively, and the substrate 136 may vibrate according to the extension and contraction of the piezoelectric sheets 132 and 134 in the length extending direction of the piezoelectric element 130 (as indicated by arrow AA' in fig. 2). Specifically, when the current is applied in the thickness direction BB 'of the piezoelectric element 130, the piezoelectric sheet on one side of the substrate 136 may contract in the length extending direction thereof, and the piezoelectric sheet on the other side of the substrate 136 may elongate in the length extending direction thereof, thereby driving the substrate 136 to perform flexural vibration in a direction perpendicular to the surface of the substrate 136 (i.e., the thickness direction BB').
In some embodiments, the material of piezoelectric sheets 132 and/or 134 may include piezoelectric ceramics, piezoelectric quartz, piezoelectric crystals, piezoelectric polymers, etc., or any combination thereof. Exemplary piezoelectric crystals may include crystal, sphalerite, diborite, tourmaline, zincite, gaAs, barium titanate and its derivative structure crystals, KH2PO4, naKC4H4O 6.4h2o (rocholite), and the like. Exemplary piezoelectric ceramic materials may include Barium Titanate (BT), lead zirconate titanate (PZT), lead barium lithium niobate (PBLN), modified lead titanate (PT), aluminum nitride (AIN), zinc oxide (ZnO), and the like, or any combination thereof. Exemplary piezoelectric polymer materials may include polyvinylidene fluoride (PVDF) and the like.
The resonance of the elastic mass end composed of the second vibration element 120 and the elastic element 140 may generate a first resonance peak having a lower frequency, and the resonance of the piezoelectric element 130 and the first vibration element 110 may generate a second resonance peak having a higher frequency. For example, a first resonant frequency f corresponding to a first resonant peak 0 May range from 50Hz to 2000 Hz, and a second resonant frequency f corresponding to the second resonant peak 1 May range from 1kHz to 10kHz. In some embodiments, when the vibration signal is output from the mass element (i.e., the second vibration element 120) at the elastic mass end, a flat frequency response curve (as shown by curve L41 in fig. 4) is formed between the first resonance peak and the second resonance peak of the frequency response curve of the acoustic output device 200. In some embodiments, the magnitude of the first resonant frequency corresponding to the first resonant peak is affected by the mass of the second vibration element 120 and the elastic coefficient of the elastic element 140. In some embodiments, the first resonant frequency of the first resonant peak may be determined according to equation (1):
Wherein f 0 Represents the first resonant frequency, k represents the elastic coefficient of the elastic element 140, and m represents the mass of the second vibration element 120.
Referring to FIG. 3, a second resonance frequency f of the second resonance peak 1 Can be approximated by a beam-like structureThe first order resonance peak of the frequency response of the equal length piezoelectric cantilever free ends 138 of the piezoelectric elements 130. For example, the second resonant frequency of the second resonant peak may be determined according to equation (2):
where b is the width of the piezoelectric element 130, E b Modulus of elasticity, I, of the material of the substrate 136 b Moment of inertia, E, of the region of the substrate 136 p Elastic modulus, I, of the material of the piezoelectric sheet 132 or 134 p ρl is the density per unit length of the piezoelectric sheet 132 or 134, and l is the length of the piezoelectric element 130, which is the moment of inertia of the region of the piezoelectric sheet 132 or 134. It should be noted that, in the present specification, the piezoelectric cantilever may refer to a structure in which the piezoelectric element 130 is not connected to the elastic element 140 and the second vibration element 120 in a single beam structure as shown in fig. 2.
Moment of inertia I of the region of the substrate 136 b The method meets the following conditions:
wherein h is b Is the thickness of the substrate 136.
Moment of inertia I of the region of the piezoelectric sheet 132 or 134 p The method meets the following conditions:
wherein h is p Is the thickness of the piezoelectric sheet 132 or 134.
Density per unit length ρ of piezoelectric element 130 l The method meets the following conditions:
ρ l ＝bh b ρ b +2·bh p ρ p ， (5)
Wherein ρ is b For the substrate 136 density ρ p Is the material density of the piezoelectric sheet 132 or 134.
Thus, in some embodiments, the performance parameters of the piezoelectric element 130 may be determined by(e.g., material parameters (including modulus of elasticity, density), geometric parameters (including thickness, length), etc.) are designed to adjust the second resonant frequency f of the acoustic output device 200 1 。
Specifically, in some embodiments, the flat curve range in the frequency response curve of the acoustic output device 200 may be adjusted by adjusting the length of the piezoelectric element 130. In some embodiments, as shown in fig. 5, in order to ensure sound quality, as few high-order modes (or vibration modes) as possible occur in the audible range (20 Hz to 20 kHz), the beam-like structure of the piezoelectric element 130 should be as short as possible. In some embodiments, to ensure sensitivity of the acoustic output device 200 at low frequency bands (e.g., 100Hz-1000 Hz), the length of the beam-like structure of the piezoelectric element 130 cannot be too short. In some embodiments, to increase the sensitivity of the acoustic output device 200 at low frequency bands (e.g., 100Hz-1000 Hz) and with a flat frequency response curve in the interval 100Hz-500 Hz, the piezoelectric element 130 may have a length between 20mm-30 mm. In some embodiments, the piezoelectric element 130 may have a length between 10mm-20mm in order not to decrease the sensitivity of the acoustic output device 200 in the low frequency range (e.g., 100Hz-800 Hz) and have a flat frequency response curve in the 200Hz-2000 Hz interval. In some embodiments, the piezoelectric element 130 may have a length between 3mm-10mm in order for the acoustic output device 200 to have a flat frequency response curve in the 200Hz-5kHz range. In some embodiments, fine tuning of the resonance peak (e.g., the first resonance peak and/or the second resonance peak) may also be achieved by adjusting the mass of the mass end (i.e., the first piezoelectric element 110) (as shown in fig. 6).
In some embodiments, specific structural parameters of the acoustic output device 200 may be designed based on the output requirements of the acoustic output device 200. For example, the first resonant frequency f can be determined first according to actual requirements 0 And a second resonant frequency f 1 Is (e.g. 50Hz<f 0 <2000Hz，200Hz<f 1 <40kHz, wherein f 0 <f 1 ). Next, the mass of the second vibration element 120 (e.g., vibration plate) of the elastic mass end can be determined. Then, it may be required according to the size of the acoustic output device 200The width of the piezoelectric element 130 is determined (mainly based on the spatial dimensions). Finally, the thickness of the substrate 136 and the thickness of the piezoelectric sheet may be determined based on the fabrication process technology capabilities of the piezoelectric sheet.
After determining the above parameters, the elastic coefficient of the elastic element 140 may be calculated:
k＝(2πf 0 ) 2 m， (6)
the length of the piezoelectric element 130 may then be determined based on the material parameters (e.g., modulus of elasticity, density, etc.) and geometric parameters (e.g., thickness, length, etc.) of the piezoelectric element 130.
Eventually, all geometrical parameters of the acoustic output device 200 can be determined.
Fig. 4 is a graph of output frequency response versus elastic mass end of an exemplary acoustic output device according to some embodiments of the present description. As shown in fig. 4, a curve L41 represents the frequency response curve of the acoustic output device 200 when the vibration signal is output from the elastic mass terminal. The curve L42 represents the frequency response curve of the acoustic output device 200 when the vibration signal is output from the mass end. The first resonance peak in the virtual coil X may be generated by resonance of the second vibration element 120 and the elastic element 140. The second resonance peak in the virtual coil Y may be generated by resonance of the piezoelectric element 130 and the first vibration element 110. As can be seen from FIG. 4, curves L41 and L42 each have 2 resonance peaks in the 20Hz-2kHz range. When the vibration signal is output from the mass end (corresponding to the curve L42), the acoustic output device 200 has higher sensitivity in the middle-high frequency band (e.g., 600Hz-5 kHz). But there is a resonance valley between the first resonance peak and the second resonance peak, thereby affecting the sound quality of the middle-low frequency band (e.g., 200Hz-1000 Hz) of the acoustic output device 200. Therefore, when the application scenario of the acoustic output device 200 requires higher sensitivity for the middle-high frequency band, it may be preferable to output the vibration signal through the mass terminal. When the vibration signal is output from the elastic mass end (corresponding to the curve L41), the acoustic output device 200 has a relatively flat frequency response curve between the first resonance peak and the second resonance peak, so that the acoustic output device 200 has a relatively good sound quality in the audible domain.
Fig. 5 is a graph comparing the frequency response of the piezoelectric cantilever free end output with the frequency response of an acoustic output device comprising a single beam structure of the same beam length, according to some embodiments of the present disclosure. As shown in fig. 5, curves L51, L52, L53 represent the frequency response curves of piezoelectric cantilevers with lengths of 25mm, 15mm, 5mm, respectively. L51', L52', L53' represent the frequency response curves of acoustic output devices comprising single beam structures with beam lengths of 25mm, 15mm, 5mm, respectively. It can be seen from the curves L51, L52, L53 in fig. 5 that the shorter the piezoelectric cantilever (e.g., the less high order modes it has in the audible range (20 Hz to 20 kHz). As can be seen from a comparison of the curves L51 and L51', L52 and L52', L53 and L53', when the beam length of the piezoelectric cantilever is the same as that of the single beam structure, the first order resonant frequency of the free end output of the piezoelectric cantilever is similar to the second resonant frequency of the acoustic output device of the single beam structure including the corresponding beam length. Therefore, in order for the acoustic output device to exhibit as few higher order modes (or vibrational modes) as possible in the audible range, the beam-like structure of the piezoelectric element 130 in the single beam structure should be as short as possible. Further, as can be seen from the curves L51', L52', L53', at various beam lengths (i.e., lengths of the piezoelectric elements 130 in the single-beam structure), a first resonance frequency of the single-beam structure (i.e., a frequency of a resonance peak generated by the elastic element 140 in the single-beam structure resonating with the second vibration element 120) (a frequency corresponding to the resonance peak in the broken line circle M) slightly increases due to a decrease in beam shortening mass, and a straight curve is formed between both the first resonance peak and the second resonance peak.
Fig. 6 is a plot of the frequency response of an acoustic output device including a first vibrating element of different masses, according to some embodiments of the present description. As shown in fig. 6, in the case where the piezoelectric elements 130 are equal in length, the resonance peak of the acoustic output device 200 moves toward low frequency as the mass of the mass end (the first vibration element 110) increases. Thus, in some embodiments, fine tuning of the first formant location (formant in dashed circle O) and the second formant location (formant in dashed circle P) may be achieved by increasing or decreasing the mass of the mass end (first vibrating element 110) to move the frequency response curve of acoustic output device 200 from side to side as a whole. In some embodiments, the mass of the first vibratory element 110 can be adjusted according to the flat frequency response range that is actually needed. For example, if it is desired to lower the flat frequency response range of the acoustic output device, a first vibrating element 110 of greater mass may be provided. Conversely, if it is desired to shift the flat frequency response range of the acoustic output device to higher frequencies, a first vibrating element 110 of smaller mass may be provided. In some embodiments, the mass of the first vibratory element 110 can be in the range of 0-10 g. For example, when it is desired to flatten the acoustic output device at a frequency response curve of 200Hz-900 Hz, the mass of the first vibrating element 110 can be between 0g and 0.5g. For another example, when it is desired to flatten the acoustic output device frequency response curve at 160Hz-800 Hz, the mass of the first vibrating element 110 can be between 0.5g-1g. For another example, the mass of the first vibration element 110 may be between 1g and 2g when it is desired to flatten the acoustic output device at a frequency response curve of 150Hz-700 Hz.
As can be seen from fig. 2-6, the flat area of the frequency response curve of the acoustic output device 200 can be located between the first resonance peak and the second resonance peak, so that to make the frequency response curve of the acoustic output device 200 flat over a wider frequency range, the distance between the first resonance peak and the second resonance peak can be increased, i.e. the first resonance frequency can be decreased and/or the second resonance frequency can be increased. As can be seen from the formula (2), when the piezoelectric element 130 having a shorter length is selected, the second resonance frequency increases. However, too short a length of the piezoelectric element 130 may cause the overall amplitude of the frequency response curve to decrease, thereby decreasing the sensitivity of the acoustic output device 200. To solve the above-described problem, in some embodiments, the acoustic output device 200 may employ a structure (may also be referred to as a single beam structure) including a plurality of structures as shown in fig. 2 (for example, two structures symmetrically arranged in fig. 7 or 17), which can improve sensitivity without affecting the overall output sound quality of the acoustic output device 200. In some embodiments, the symmetrical structure also reduces unnecessary wobble, offset, and avoids adversely affecting the output sound quality of the acoustic output device 200. The symmetrical structure may include a structure in which the plurality of piezoelectric elements 130 are centered on the mass end (the first vibration element 110), and a structure in which the plurality of piezoelectric elements 130 are centered on the elastic mass end (the elastic element 140 and the second vibration element 120), and the specific details thereof may be seen in fig. 7, 8, 16, 17 and the related descriptions.
Fig. 7 is a schematic structural diagram of an acoustic output device according to some embodiments of the present description. In some embodiments, as shown in fig. 7, the acoustic output device 700 may include a piezoelectric element 130, a first vibration element 110, a second vibration element 120, and an elastic element 140. In some embodiments, the piezoelectric element 130 may include a beam-like structure with the first vibration element 110 coupled to the first location of the piezoelectric element 130. The second vibration element 120 may be connected to the second position of the piezoelectric element 130 by an elastic element 140. It is to be noted that, when the piezoelectric element 130 of the beam-like structure vibrates, the amplitude of the end portion thereof is large, and therefore, when the first position or the second position is located at the end portion of the beam-like structure, the output response sensitivity of the corresponding vibration element end is high, and the sound quality is good.
In some embodiments, as shown in fig. 7, the first position may be located at the center of the length extension direction of the beam-like structure (e.g., the first vibration element 110 may be attached to an intermediate position of one surface of the piezoelectric element 130), and the second position may be located at both ends of the length extension direction of the beam-like structure (e.g., the elastic element 140 may be attached to both ends of the other surface of the piezoelectric element 130), thereby realizing a symmetrical structure in which the piezoelectric element 130 passes the first position and the plane perpendicular to the length extension direction of the beam-like structure is a symmetrical plane. In this case, the piezoelectric element 130 may be regarded as including two sub-piezoelectric elements, and the first and second vibration elements 110 and 120 may be regarded as including two sub-vibration elements, respectively. As shown in fig. 7, the structure in the dashed frame C or C' is the same as the single beam structure shown in fig. 2, i.e., one end of the piezoelectric element is connected to the vibration element, and the other end thereof is connected to the other vibration element through the elastic element. Accordingly, the structure of the acoustic output device 700 including the two single beam structures as shown in fig. 7 may be referred to as a double beam structure. In some embodiments, the piezoelectric element 130 may include two sub-piezoelectric elements. One end of each sub-piezoelectric element may be connected to one sub-vibration element. The other end of each sub-piezoelectric element may be connected to the second vibration element 120 through an elastic member 140. In this case, each sub-piezoelectric element may belong to a single beam structure. In some embodiments, the piezoelectric elements in the two single beam structures may be in a straight line. The two single beam structures may be symmetrically arranged. In some embodiments, the acoustic device 700 may include a four-beam structure. In other words, the acoustic output device 700 may include 4 single beam structures. For example, the acoustic output device 700 may also include another piezoelectric element, which may be disposed in a cross-shape with the piezoelectric element 130. The other piezoelectric element may be connected to the second vibration element through an elastic element. It should be appreciated that in the present application, the multi-beam structure may not necessarily include a corresponding number of piezoelectric elements 130, so long as the structure of the acoustic output device may be equivalent to a plurality of single-beam structures. For example, the double beam structure shown in fig. 7 may include only one piezoelectric element 130. For another example, the four-beam structure of the "cross" shape may include only 2 piezoelectric elements 130 disposed to intersect each other.
In some embodiments, the acoustic output device 700 may further include a connector 190, and the second vibration element 120 and the elastic element 140 may be connected to the second position of the piezoelectric element 130 by the connector 190. The connection member 190 is disposed at the second position of the piezoelectric element 130, one end of the elastic element 140 is connected to the connection member 190, and the other end of the elastic element 140 is connected to the second vibration element 120. The arrangement of the connection member 190 allows the vibration at the second position of the piezoelectric element 130 to be transmitted to the elastic element 140 and the second vibration element 120, and also allows the structure of the elastic element 140 to be more flexibly arranged. For example, as shown in fig. 7, the elastic member 140 may include a plurality of elastic rods. The elastic rod may be connected to the piezoelectric element 130 by a connection 190. In this case, the elastic rod may have longitudinal elasticity in the vibration direction of the second vibration element 120, and may also have transverse elasticity in the vibration direction perpendicular to the second vibration element 120. As another example, as shown in fig. 8, the elastic member 140 may be a spring. The second vibration element 120 may be a vibration plate. The length of the vibration plate may be longer than or equal to the length of the beam-like structure.
In some embodiments, the plurality of elastic rods may be axisymmetrically distributed with respect to an axis passing through the center of the second vibration element 120. For example, as shown in fig. 7, the acoustic output device 700 may include 4 elastic bars, and the 4 elastic bars are distributed in an "x" shape on both sides of the second vibration element 120. In some embodiments, the second vibration element 120 may correspond to a middle position of the beam-like structure, so that the second vibration element 120 is not prone to shake in a non-vibration direction, thereby improving the flatness of the output response curve of the elastic mass end of the acoustic output device 700.
Fig. 8 is a schematic structural view of an acoustic output device according to some embodiments of the present description. As shown in fig. 8, the acoustic output device 800 may have a similar structure to the acoustic output device 700. For example, the acoustic output device 800 may include a piezoelectric element 130, a first vibration element 110, a second vibration element 120, and an elastic element 140. For another example, the piezoelectric element 130 may include a beam-like structure, and the first vibration element 110 is connected to the center of the beam-like structure in the length extension direction. The second vibration element 120 may be connected to both ends of the beam-like structure in the length extension direction by elastic elements 140.
In some embodiments, as shown in fig. 8, the length of the second vibration element 120 may be longer than or equal to the length of the piezoelectric element 130 (or beam-like structure). For example, the second vibration element 120 may be a vibration plate having the same shape as the piezoelectric element 130. The vibration plate and the piezoelectric element 130 may be disposed opposite to each other. The elastic element 140 may be a spring or a rod made of other materials with a small elastic coefficient. The elastic member 140 may be vertically disposed between the second vibration member 120 and the piezoelectric member 130.
In some embodiments, the number of the second vibration elements 120 may be 1 or more. For example, the piezoelectric element 130 may be connected to the same second vibration element 120 through a plurality of elastic elements 140 (as shown in fig. 8). For another example, each second position of the piezoelectric element 130 may correspond to one second vibration element 120, and the piezoelectric element 130 may be connected to the corresponding second vibration element 120 through one or more elastic elements 140.
Fig. 9 is a plot of frequency response of vibration signals from an elastic mass terminal of an acoustic output device having a single beam structure, a double beam structure, and a four beam structure, respectively, according to some embodiments of the present disclosure. As shown in fig. 9, a curve L91 represents a frequency response curve when a vibration signal of an acoustic output device (for example, the acoustic output device 200) having a single beam structure is output from an elastic mass terminal. Curve L92 represents the frequency response curve of a vibration signal of an acoustic output device (e.g., acoustic output device 700) having a double beam structure when output from the mass end. Curve L93 represents the frequency response curve of the vibration signal of the acoustic output device having the four-beam structure when the vibration signal is output from the mass terminal. As can be seen from fig. 9, the output sensitivity of the acoustic output device (corresponding to the curve L92) employing the double-beam structure is higher than that of the acoustic output device (corresponding to the curve L91) having the single-beam structure. The sensitivity of the straight curve segment between the first and second resonance peaks is improved by about 6dB. The sensitivity of the straight curve segment between the first and second resonance peaks of the acoustic output device (corresponding to curve L93) employing the four-beam structure is improved by about 12dB as compared to the acoustic output device having the single-beam structure (corresponding to curve L91).
As is clear from the curves L91, L92, and L93, the frequency of the first resonance peak gradually shifts to a high frequency as the number of single beam structures in the acoustic output device increases. This is because the symmetrical distribution of the plurality of single beam structures introduces the plurality of elastic elements 140 in parallel, so that the overall elastic coefficient increases, thereby increasing the frequency of the first resonance peak.
As can be seen from the curve L41 in fig. 4, when the vibration is output from the elastic mass end of the acoustic output device 200, the curve between the first resonance peak and the second resonance peak is flat, but the high-band mode larger than the second resonance peak increases and the amplitude decreases. To address this issue, in some embodiments, the amplitude of the frequency band of the acoustic output device after the second resonance peak may be supplemented with an additional second piezoelectric element 150.
Fig. 10 is a schematic structural view of an acoustic output device according to some embodiments of the present description. As shown in fig. 10, the acoustic output device 1000 may include a first vibration element 110, a second vibration element 120, a first piezoelectric element 130, an elastic element 140, and a connection 190. In some embodiments, the acoustic output device 1000 can also include a second piezoelectric element 150. The first piezoelectric element 130 and the second piezoelectric element 150 may each include a beam-like structure. In some embodiments, the first vibration element 110 may be connected to a central position of the piezoelectric element 130 in the length extension direction. The second vibration element 120 may be connected to an end of the piezoelectric element 130 through an elastic element 140.
In some embodiments, the length of the beam-like structure of the second piezoelectric element 150 (which may also be referred to as a second length) may be shorter than the length of the beam-like structure of the first piezoelectric element 130 (which may also be referred to as a first length). In some embodiments, the ratio between the second length and the first length may be in the range of 0.1-1. In some embodiments, the ratio between the second length and the first length may be in the range of 0.3-0.7. In some embodiments, the ratio between the second length and the first length may be in the range of 0.4-0.6. As can be seen from fig. 5, as the length of the piezoelectric element is shorter, the output frequency response thereof shifts to a high frequency. Accordingly, a piezoelectric element having a longer beam-like structure may be referred to as a low-frequency piezoelectric element, and a piezoelectric element having a shorter beam-like structure may be referred to as a high-frequency piezoelectric element. In some embodiments, the entirety of the structure of the acoustic output device 700 as in fig. 7 or the acoustic output device 800 as in fig. 8 may constitute one unit. In some embodiments, the acoustic output device 1000 may include a low frequency unit 1010 including a low frequency piezoelectric element and a second piezoelectric element 150.
The second piezoelectric element 150 may be connected to the second vibration element 120 such that it receives the vibration of the second vibration element 150. For example, the second piezoelectric element 150 may be attached to the second vibration element 120. The second piezoelectric element 150 resonates to generate a third resonance peak having a frequency higher than the second resonance frequency of the low frequency unit 1010. In some embodiments, the third resonance peak may correspond to a third resonance frequency in the range of 10kHz-40kHz. In some embodiments, the third resonant frequency may have a frequency in the range of 20kHz-30kHz.
In some embodiments, as shown in fig. 10, the acoustic output device 1000 may further include a resilient element 142 and a vibrating element 125. The vibration element 125 may be connected to the second piezoelectric element 150 through the elastic element 142. The second vibration element 120, the vibration element 125, the second piezoelectric element 150, and the elastic element 142 may constitute a high frequency unit 1020 of the acoustic output device 1000. In other words, the acoustic output device 1000 may include a low frequency unit 1010 and a high frequency unit 1020. The high frequency unit 1020 and the low frequency unit 1010 may be connected through the second vibration element 120. That is, the elastic mass end of the low frequency unit 1010 and the mass end of the high frequency unit 1020 may share one vibration element (i.e., the second vibration element 120), thereby achieving connection of the high frequency unit 1020 and the low frequency unit 1010. In this case, the vibration of the acoustic output device 1000 may be output through the first vibration element 110 and/or the vibration element 125. The second length of the second piezoelectric element 150 in the high frequency unit 1020 is shorter than the first length of the first piezoelectric element 130 in the low frequency unit 1010. The resonance of the second piezoelectric element 150 and the second vibration unit 130 may provide the third resonance peak described above for the acoustic output device 1000. In addition, the resonance of the elastic element 142 and the vibration element 125 of the high frequency unit 1020 may also provide a fifth resonance peak for the acoustic output device 1000. The frequency response curve between the first resonance peak (i.e., the fifth resonance peak) and the second resonance peak (i.e., the third resonance peak) of the high frequency unit 1020 is relatively flat. In some embodiments, the fifth resonant frequency corresponding to the fifth resonant peak may be less than or greater than the second resonant frequency corresponding to the second resonant peak. In some embodiments, the fifth resonant frequency and the second resonant frequency can be made similar by adjusting the performance parameters (e.g., the material parameters or the geometric parameters of the piezoelectric element, the mass of the mass end or the elastic mass end, etc.) of the high-frequency unit 1020 and/or the low-frequency unit 1010, so that the frequency range in which the output frequency response of the high-frequency unit 1020 and the output frequency response of the low-frequency unit 1010 may interfere with each other can be reduced, and the sound quality of the acoustic output device 1000 can be improved. In some embodiments, the relationship between the second resonance peak (i.e., the second resonance peak) of low frequency unit 1010 and the first resonance peak (i.e., the fifth resonance peak) of high frequency unit 1020 may satisfy the following equation:
Wherein f 1 A frequency representing a second resonance peak of the low frequency unit 1010 (i.e., a second resonance frequency); f (f) 0 ' represents the frequency of the first resonance peak of the high frequency unit 1020 (i.e., the fifth resonance frequency). In some embodiments, the fifth resonant frequency may be between 5kHz and 40kHz when the second resonant frequency is between 8kHz and 10 kHz. In some embodiments, the fifth resonant frequency may be between 4kHz and 25kHz when the second resonant frequency is between 5kHz and 8 kHz. In some embodiments, the fifth resonant frequency may be between 100Hz-10kHz when the second resonant frequency is between 2kHz-5 kHz. In some embodiments, the fifth resonant frequency may be between 100 Hz-5kHz when the second resonant frequency is between 1kHz-3 kHz.
It should be noted that, the number of the first piezoelectric elements 130 of the low frequency unit 1010 and the number of the second piezoelectric elements 150 of the high frequency unit 1020 of the acoustic output apparatus 1000 may be one or more, and the number of the first piezoelectric elements 130 may be the same as or different from the number of the second piezoelectric elements 150. For example, the acoustic output device 1000 may include only one piezoelectric element 130 and one second piezoelectric element 150, and at this time, the vibration element 125 may be connected to both ends of the second piezoelectric element 150 through the elastic element 142, and the second vibration element 120 may be connected to both ends of the second piezoelectric element 150 through the elastic element 140. For another example, the acoustic output device 1000 may also include two first piezoelectric elements 130 and one second piezoelectric element 150, where the vibration element 125 may be connected to two ends of the second piezoelectric element 150 through the elastic element 142, and the second vibration element 120 may be connected to one end of each of the first piezoelectric elements 130 through the elastic element 140. The other end of each of the first piezoelectric elements 130 may be connected to the first vibration element 110.
Fig. 11 is an output frequency response plot of an exemplary acoustic output device according to some embodiments of the present description. Fig. 12 is a plot of the frequency response of the acoustic output device for different excitation signal phase differences. Fig. 13 is a plot of the frequency response of the acoustic output device for different excitation signal phase differences. As shown in fig. 11, a curve L111 represents a frequency response curve of an acoustic output device having a single beam structure when a vibration signal is output from an elastic mass terminal. Curve L112 represents the frequency response curve of an acoustic output device having a double beam structure when the vibration signal is output from the sprung mass end. Curve L113 represents the frequency response curve of an acoustic output device having a two-cell structure (i.e., a high frequency cell and a low frequency cell) when a vibration signal is output from the elastic mass terminal. Here, the acoustic output device having the dual-unit structure may be a structure having the acoustic output device 1000 as shown in fig. 10, and the excitation signal (e.g., excitation voltage) of the high-frequency unit 1020 and the excitation signal of the low-frequency unit 1010 have a phase difference of 0 °. As can be seen in fig. 11, the acoustic output device 1000 has a resonance valley after the first resonance peak due to the resonance of the intermediate second vibrating element 120. In some embodiments, the resonant valley may be filled by modulating the phase between the excitation signal of the second piezoelectric element 150 of the high frequency unit 1020 and the first piezoelectric element 130 of the low frequency unit 1010. As shown in fig. 12, the resonance valley amplitude gradually increases as the phase difference of the high-low frequency unit excitation signals increases (corresponding to the curves L121-124). In some embodiments, the absolute value of the high and low frequency unit excitation signal phase difference (i.e., the phase difference of the second piezoelectric element 150 and the piezoelectric element 130) ranges from 45 ° -180 °. It should be noted that, as shown in fig. 13, when the absolute value of the phase difference between the second piezoelectric element 150 and the first piezoelectric element 130 is greater than 135 °, the low frequency amplitude before the first resonance peak is reduced, so in order to secure the low frequency amplitude of the acoustic output device 1000, the absolute value of the phase difference between the second piezoelectric element 150 and the piezoelectric element 130 may range from 45 ° to 135 °. In some embodiments, the absolute value of the phase difference of the second piezoelectric element 150 and the piezoelectric element 130 may range from 50 ° to 110 °. In some embodiments, the absolute value of the phase difference of the second piezoelectric element 150 and the piezoelectric element 130 may range from 70 to 90. Fig. 14 is a schematic diagram of an exemplary acoustic output device according to some embodiments of the present description. As shown in fig. 14, in order to further enhance the low frequency response of the acoustic output device, the acoustic output device 1400 may further include a third piezoelectric element 160 based on the structure of the acoustic output device 1000. The third piezoelectric element 160 may vibrate in response to the driving piezoelectric and transmit the vibration to the second piezoelectric element 150. In some embodiments, the first piezoelectric element 130, the second piezoelectric element 150, and the third piezoelectric element 160 may each comprise a beam-like structure. The length of the beam-like structure of the third piezoelectric element 160 (which may also be referred to as a third length) may be longer than the length of the beam-like structure of the second piezoelectric element 150 (i.e., a second length). In some embodiments, the third length of the third piezoelectric element 160 may be between two lengths of the second piezoelectric element 150 and the first length of the first piezoelectric element 130. In some embodiments, the third length of the third piezoelectric element 160 may be equal to the first length of the first piezoelectric element 130. In some embodiments, the third length of the third piezoelectric element 160 is less than the second length of the second piezoelectric element 150, and the third piezoelectric element 160 may resonate to generate a fourth resonant peak having a frequency lower than the third resonant peak.
In some embodiments, the acoustic output device 1400 may also include a third vibration element 127. The third vibration element 127 may be connected to the second piezoelectric element 150 and to the third piezoelectric element 160 at least through the second elastic element 145. Accordingly, the vibration of the third piezoelectric element 160 can be transmitted to the second piezoelectric element 150 through the third vibration element 127. In some embodiments, the acoustic output device 1400 may also include a vibration element 129. The vibration element 129 may be located at a central position in the length extension direction of the third piezoelectric element 160. The third vibration element 127, the vibration element 129, the third piezoelectric element 160, and the second elastic element 145 may constitute a second low-frequency unit 1015 similar in structure to the low-frequency unit 1010 (may also be referred to as a first low-frequency unit). In other words, the acoustic output device 1000 may include a low frequency unit 1010, a second low frequency unit 1015, and a high frequency unit 1020. In some embodiments, the low frequency unit 1010 and the second low frequency unit 1015 may be connected in parallel, thereby boosting the low frequency response of the acoustic output device 1400 (as shown in fig. 15). In some embodiments, the acoustic output device 1000 includes a low frequency unit 1010, a second low frequency unit 1015, and a high frequency unit 1020 may also be referred to as the acoustic output device 1000 including a three-unit structure.
Specifically, as shown in fig. 14, the first piezoelectric element 130 and the third piezoelectric element 160 may be arranged in parallel. The elastic mass end of the low frequency unit 1010 (i.e., the second vibration element 120) may be connected to the elastic mass end of the second low frequency unit 1015 (i.e., the third vibration element 127). The second piezoelectric element 150 may be directly connected to the connected second vibration element 120 and/or third vibration element 127. The whole of the second vibration element 120 and the third vibration element 127 after connection may serve as a mass end of the high-frequency unit 1020. In some embodiments, the mass end of the low frequency unit 1010 (i.e., the first vibration element 110) and the mass end of the second low frequency unit 1015 (i.e., the vibration unit 129) may be connected (as shown in fig. 14) or may be separate. The separate structure may enable the mass end of the low frequency unit 1010 and the mass end of the second low frequency unit 1015 to generate vibrations, respectively. The connection structure may make the vibration output frequency response of both the mass end of the low frequency unit 1010 and the mass end of the second low frequency unit 1015 coincide. In some embodiments, the mass end of the low frequency unit 1010 may be connected to the mass end of the second low frequency unit 1015.
In some embodiments, the low frequency unit 1010, the low frequency unit 1015, and the high frequency unit 1020 may be the same or different in structure. For example, the low frequency unit 1010 and the low frequency unit 1015 may each have a structure such as the acoustic output device 800, and the high frequency unit 1020 may have a structure such as the acoustic output device 700. For another example, the low frequency unit 1010, the low frequency unit 1015, and the high frequency unit 1020 may each have a structure like the acoustic output device 800.
In some embodiments, the acoustic output device 1400 may not include the third vibration element 127. The vibration of the third piezoelectric element 160 of the low frequency unit 1015 may be transferred to the second vibration element 120 through the second elastic element 145, and then transferred to the second piezoelectric element 150 through the second vibration element 120. In other words, as shown in fig. 14, the second vibration element 120 and the third vibration element 127 can be regarded as a whole, and the vibration of the piezoelectric element 130 of the low frequency unit 1010 and the vibration of the third piezoelectric element 160 of the low frequency unit 1015 are transmitted to the same second vibration element, thereby reducing the number of vibration elements and saving resources.
Fig. 15 is a graph of output frequency response of an acoustic output device of different construction according to some embodiments of the present disclosure. As shown in fig. 15, a curve L151 represents a frequency response curve of an acoustic output device (e.g., acoustic output device 1000) having a two-cell structure (i.e., a high-frequency cell and a low-frequency cell) when a vibration signal is output from an elastic mass terminal. The curve L152 represents the frequency response curve of the acoustic output device 1400 including the low frequency unit 1010, the second low frequency unit 1015, and the high frequency unit 1020 when the vibration signal is output from the mass terminal. As can be seen from fig. 15, the low frequency response of the acoustic output device 1400 (corresponding to 20Hz-500 Hz in curve L152) is significantly higher than that of the acoustic output device 1000 having a dual cell structure.
Fig. 16 is a schematic structural view of an exemplary acoustic output device according to some embodiments of the present description. As shown in fig. 16, the acoustic output device 1600 may include a first vibration element 110, a second vibration element 120, a piezoelectric element 130, and an elastic element 140. The piezoelectric element 130 may include a beam-like structure, and the first vibration element 110 may include sub-vibration elements 112 and 114. In some embodiments, the sub-vibration elements 112 and 114 may be connected to both ends (also referred to as first positions) of the length extension direction of the piezoelectric element 130, respectively. The second vibration element 120 may be connected to the piezoelectric element 130 at a second position by an elastic element 140. For example, the second vibration element 120 may be disposed at a central position (i.e., a second position) of the piezoelectric element 130 in the length extension direction by the connection member 190 and the elastic element 140. In some embodiments, the piezoelectric element 130 may include two sub-piezoelectric elements. One end of each sub-piezoelectric element may be connected to one sub-vibration element (112 or 114), respectively. The other end of each sub-piezoelectric element may be connected by a connection 190. In this case, the structure of the acoustic output device 1600 can be regarded as including two single beam structures as shown in fig. 2.
In some embodiments, the masses of the sub-vibrating elements 112 and 114 may be the same, and the two first locations at which the sub-vibrating elements 112 and 114 are connected to the piezoelectric element 130 are symmetrical with respect to the center of the piezoelectric element 130, such that the sub-vibrating elements 112 and 114 are symmetrical with respect to the center of the piezoelectric element 130. The symmetry balances each other to reduce unwanted wobble of the sub-vibration element 112 and to improve the flatness of the frequency response curve of the acoustic output device 1600.
In some embodiments, the number of piezoelectric elements 130 may include one or more. Accordingly, the number of the first vibration elements 110 directly connected to the piezoelectric element 130 may include a plurality. For example, the number of the piezoelectric elements 130 may be 2. The two piezoelectric elements 130 may be cross-connected together in a cross-shape by a connector. Further, an end of each piezoelectric element 130 may be arranged with the first vibration element 110. The second vibration element 120 may be connected at the crossing point of the cross shape by the elastic element 140. For another example, the number of the piezoelectric elements 130 may be 4, and one end of each of the four piezoelectric elements 130 may be connected by the connection member 190, so that the 4 piezoelectric elements 130 are disposed on the circumferential side of the connection member 190 in a cross shape, and each of the piezoelectric elements 130 may be connected to one of the first vibration elements 110. In some embodiments, the plurality of piezoelectric elements 130 may also correspond to one first vibration element 110. Illustratively, four piezoelectric elements 130 are disposed around the connecting member 190 in a cross shape, and each piezoelectric element 130 may be connected to one ring-shaped first vibration element 110.
In some embodiments, as shown in fig. 16, the resilient element 140 may comprise a plurality of resilient bars. The elastic rod may be connected to the piezoelectric element 130 by a connection 190. In this case, the elastic rod may have a first elastic coefficient in the vibration direction of the second vibration element 120, and may also have a second elastic coefficient in the vibration direction perpendicular to the second vibration element 120. In some embodiments, in order to enable the second vibration element 120 to vibrate easily in a direction perpendicular to the surface of the piezoelectric element 130, but not shake easily in a direction parallel to the long axis of the piezoelectric element 130, the second elastic coefficient may be much larger than the first elastic coefficient. For example, the ratio of the second elastic modulus to the first elastic modulus may be greater than or equal to 1×10 3 . For example, the ratio of the second elastic coefficient to the first elastic coefficient may be 1×10 3 、1×10 4 、1×10 5 、1× 10 6 、1×10 10 Etc. In some embodiments, the elastic element 140 may be a vibration-transmitting sheet.
Fig. 17 is a schematic diagram of an exemplary acoustic output device according to some embodiments of the present description. As shown in fig. 17, the acoustic output device 1700 may have a similar structure to the acoustic output device 1600. In some embodiments, as shown in fig. 17, the elastic element 140 may also be a spring or a rod made of other materials with a smaller elastic coefficient. The elastic member 140 may be vertically disposed between the second vibration member 120 and the piezoelectric member 130.
Fig. 18 is a graph of frequency response of vibration signals output from the sprung mass end of the acoustic output device having the single beam structure, the double beam structure, and the four beam structure, respectively, according to some embodiments of the present description. As shown in fig. 18, a curve L181 represents a frequency response curve when a vibration signal of an acoustic output device (for example, the acoustic output device 200) having a single beam structure is output from an elastic mass terminal. Curve L182 represents a frequency response curve of a vibration signal of an acoustic output device (e.g., acoustic output device 1600) having a double beam structure with an elastic mass end located at a middle position in the length extension direction of the piezoelectric element when the vibration signal is output from the elastic mass end. Curve L183 shows a frequency response curve of the vibration signal of the acoustic output device having a four-beam structure with the elastic mass end located at the middle position in the length extension direction of the piezoelectric element when the vibration signal is output from the elastic mass end. As can be seen from fig. 18, the first resonance peak of the acoustic output device using the multi-beam structure (corresponding to the curve L182 or L183) moves toward the low frequency compared to the single-beam structure (corresponding to the curve L181), so that the low frequency response performance of the acoustic output device can be significantly improved using the multi-beam structure.
The acoustic output device provided by the embodiment of the application may have beneficial effects including but not limited to: (1) In the acoustic output device, the first vibration element is directly connected with the piezoelectric element, and the second vibration element is connected with the piezoelectric element by the elastic element, so that the acoustic output device can generate two resonance peaks, and the low-frequency response of the piezoelectric element is improved by generating a first resonance peak with lower frequency by using the resonance of the second vibration element and the elastic element; (2) When the signal is output through the second vibration element, the frequency response curve between the first resonance peak and the second resonance peak can be relatively straight, and the tone quality of the acoustic output device is improved; (3) When signals are output through the first vibrating element, the sensitivity of the acoustic output device in the middle-high frequency band can be improved, and the application of the acoustic output device in special scenes is facilitated. It should be noted that, the advantages that may be generated by different embodiments may be different, and in different embodiments, the advantages that may be generated may be any one or a combination of several of the above, or any other possible advantages that may be obtained.
While the basic concepts have been described above, it will be apparent to those skilled in the art that the foregoing detailed disclosure is by way of example only and is not intended to be limiting. Although not explicitly described herein, various modifications, improvements and adaptations of the application may occur to one skilled in the art. Such modifications, improvements, and modifications are intended to be suggested within the present disclosure, and therefore, such modifications, improvements, and adaptations are intended to be within the spirit and scope of the exemplary embodiments of the present disclosure.

Claims (10)

1. An acoustic output device, comprising:
a first vibration element;
a second vibration element; and
the piezoelectric element is used for responding to an electric signal to drive the first vibration element and the second vibration element to vibrate, and the vibration generates two resonance peaks in the audible range of human ears.
2. The acoustic output device of claim 1, wherein the resonance of the second vibration element and the elastic element produces a first resonance peak of the two resonance peaks that is lower in frequency, and the resonance of the piezoelectric element and the first vibration element produces a second resonance peak of the two resonance peaks that is higher in frequency.
3. The acoustic output device according to claim 1, wherein the piezoelectric element includes a beam-like structure, the first position is located at a center of a length extending direction of the beam-like structure, and the second position is located at an end of the length extending direction of the beam-like structure.
4. An acoustic output device according to claim 3, wherein the vibrations are transmitted to the user in a bone-conduction manner by the second vibration element.
5. The acoustic output device of claim 2, further comprising:
and a second piezoelectric element that receives vibration of the second vibration element, the second piezoelectric element resonating to generate a third resonance peak having a frequency higher than the two resonance peaks.
6. The acoustic output device of claim 5, wherein the piezoelectric element and the second piezoelectric element each comprise a beam-like structure, the length of the beam-like structure of the second piezoelectric element being shorter than the length of the beam-like structure of the piezoelectric element.
7. The acoustic output device according to claim 5, wherein an absolute value of a phase difference of the excitation signals of the piezoelectric element and the second piezoelectric element is in a range of 45 ° -135 °.
8. The acoustic output device according to any one of claims 5 to 7, further comprising:
and a third piezoelectric element that vibrates and is transmitted to the second piezoelectric element, the third piezoelectric element resonating to generate a fourth resonance peak having a frequency lower than the third resonance peak.
9. The acoustic output device of claim 1, wherein the piezoelectric element comprises a beam-like structure and the first vibrating element comprises two sub-vibrating elements, wherein,
the two sub-vibrating elements are respectively connected to two ends of the piezoelectric element in the length extending direction.
10. The acoustic output device of claim 9, wherein the masses of the two sub-vibrating elements are the same and the two first locations at which the two sub-vibrating elements are connected to the piezoelectric element are symmetrical with respect to the center of the piezoelectric element.
CN202210360069.XA 2022-04-07 2022-04-07 Acoustic output device Pending CN116939444A (en)

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TW112110919A TWI843498B (en) 2022-04-07 2023-03-23 Acoustic output device

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CN202210360069.XA CN116939444A (en) 2022-04-07 2022-04-07 Acoustic output device

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