CN105007551A

CN105007551A - Method for improving sound quality of bone conduction earphone and bone conduction earphone

Info

Publication number: CN105007551A
Application number: CN201510496617.1A
Authority: CN
Inventors: 廖风云; 陈迁; 陈皞; 齐心
Original assignee: Shenzhen Voxtech Co Ltd
Current assignee: Shenzhen Voxtech Co Ltd
Priority date: 2015-08-13
Filing date: 2015-08-13
Publication date: 2015-10-28
Anticipated expiration: 2035-08-13
Also published as: CN106954152A; CN106937222A; CN106954154A; CN106954151A; CN106954153A; CN106954155A; CN106954154B; CN106954150B; CN106937221B; CN106954155B; CN105007551B; CN106937221A; CN106954150A; CN106954151B; CN106954153B; CN106937222B; CN106954152B

Abstract

The invention discloses a method for improving the sound quality of a bone conduction earphone and a bone conduction earphone capable of improving the sound quality. The bone conduction earphone comprises a vibration unit and an earphone frame/earphone hanging belt connected with the vibration unit, wherein the vibration unit at least comprises a contact surface which is contacted with a user directly or indirectly, and pressure between the contact surface of the vibration unit and the user is greater than a third threshold, and the pressure enables the contact surface of the vibration unit to maintain a minimum force in contact with the user; and pressure between the contact surface of the vibration unit and the user is enabled to be less than a fourth threshold, and the pressure is a minimum force by which the contact surface of the vibration unit enables the user to generate a sense of pain. According to the invention, the sound quality, particularly the mid-bass sound quality, of the bone conduction earphone is improved through a specific design, and the wearing comfort of the bone conduction earphone is improved.

Description

Method for improving tone quality of bone conduction earphone and bone conduction earphone

Technical Field

The invention relates to a high-performance bone conduction earphone and a method for improving the sound quality of the bone conduction earphone through specific design, in particular to the quality of middle and low tones, reducing the sound leakage phenomenon and improving the wearing comfort level of the bone conduction earphone.

Background

Generally, a person can hear sound because air transmits vibration to the eardrum through the external auditory canal, and the vibration formed through the eardrum drives the auditory nerve of the person, thereby sensing the vibration of the sound. When the bone conduction speaker works, the bone conduction speaker can be generally transmitted to the auditory nerve of a person through the skin, subcutaneous tissues and bones of the person, so that the person can hear the sound.

Disclosure of Invention

The invention relates to a high-performance bone conduction earphone and a method for improving the sound quality of the bone conduction earphone through specific design. The bone conduction earphone comprises a vibration unit and an earphone frame/earphone hanging belt connected with the vibration unit; the vibration unit at least comprises a contact surface, at least part of the contact surface is in direct or indirect contact with a user, the pressure between the contact surface of the vibration unit and the user is greater than a first threshold value, the pressure between the contact surface of the vibration unit and the user is less than a second threshold value, and the pressure between the contact surface of the vibration unit and the user is greater than a third threshold value; the pressure between the contact surface of the vibration unit and the user is smaller than a fourth threshold value; optionally, the first threshold is greater than the third threshold, and the first threshold can improve the transmission efficiency of the high-frequency signal and improve the sound quality of the high-frequency signal; optionally, the third threshold is a minimum force for contacting the vibration unit contact surface with the user; optionally, the fourth threshold is a minimum force of the vibrating element contact surface that causes the user to generate pain sensation; optionally, the second threshold is smaller than the fourth threshold, and the second threshold can improve the transmission efficiency of the low-frequency signal and improve the sound quality of the low-frequency signal; optionally, the first threshold is 0.2N; the second threshold is 1.5N; the pressure corresponding to the third threshold value is 0.1N: the pressure corresponding to the fourth threshold value is 5N; the tone quality of the bone conduction earphone is related to the stress distribution on the contact surface of the vibration unit, and the frequency response curve of the bone conduction system is the superposition of the frequency response curves of all points on the contact surface. In a particular embodiment, the pressure between the contact surface and the user is between 0.1N and 5N, preferably between 0.2N and 4N, more preferably between 0.2N and 3N, even more preferably between 0.2N and 1.5N, even more preferably between 0.3N and 1.5N.

In one embodiment, the present invention relates to a bone conduction speaker for improving leakage sound, the speaker including a vibration unit. The vibration unit at least comprises a contact surface, and at least part of the contact surface is in direct contact or indirect contact with a user; the contact surface at least comprises a first contact surface area and a second contact surface area;

optionally, the first contact surface region includes a sound guiding hole, and the sound guiding hole guides out sound waves in the shell of the vibration unit, and the sound guiding hole is superposed with sound leakage waves to suppress sound leakage; optionally, at least one side sound-leading hole is arranged on the side surface of the shell of the vibration unit, and the sound-leading hole leads out sound waves in the shell of the vibration unit, and the sound-leading hole is superposed with sound waves of sound leakage to inhibit sound leakage; optionally, air is disposed below the first contact surface area, and a vibration panel is connected to the second contact surface area, or the vibration panel is the second contact surface area; optionally, the raised portion of the second contact surface area is higher than the first contact surface area, at least part of the first contact surface area is not in contact with the user, and the part not in contact with the user is provided with the sound guide hole. The second contact surface area is more tightly attached to a user, and the contact force is larger; optionally, the area and the shape of the vibration panel and the second contact surface area are the same; optionally, the area and the shape of the vibration panel and the second contact surface area are different, and the projected area of the vibration panel in the second contact surface area is not greater than the area of the second contact surface area.

In another embodiment, the present invention provides a bone conduction speaker for improving sound quality, comprising a housing, a transducer, a first vibrating plate; the first vibration transmission sheet is connected with the energy conversion device in a physical mode; the first vibration transmission piece is connected with the shell in a physical mode; the transducing means may generate at least one resonant peak;

optionally, the transduction device comprises at least one vibration plate and a second vibration transmission plate, and the transduction device can generate at least two resonance peaks; optionally, the transducing device comprises at least one voice coil and at least one magnetic circuit system; the voice coil is physically connected with the vibrating plate, and the magnetic circuit system is physically connected with the second vibration transmission plate; optionally, the stiffness coefficient of the vibrating plate is greater than that of the second vibration transmission plate; optionally, the first vibration transmission plate and the second vibration transmission plate are elastic plates; optionally, the first vibration transmission plate converges the convergence of the at least two first struts toward the center; preferably, the first vibration-transmitting sheet has a thickness of 0.005mm to 3mm, more preferably, 0.01mm to 2mm, still more preferably, 0.01mm to 1mm, and further preferably, 0.02mm to 0.5 mm.

In another embodiment, the present invention provides a bone conduction speaker for improving sound quality, comprising a vibration unit, wherein the vibration unit comprises at least one contact layer, and the contact layer is at least partially in direct or indirect contact with a user; the contact surface has a gradient structure, so that the pressure distribution on the contact layer is not uniform;

optionally, the gradient structure of the contact layer makes the pressure distribution of the contact with the user uneven, resulting in different frequency response curves of each contact point; the integral frequency response curve of the contact layer is formed by superposing the frequency response curves of all points; optionally, a gradient structure is arranged on the surface of the contact layer facing the user; optionally, the gradient structure comprises at least one protrusion; optionally, the gradient structure comprises at least one groove; optionally, the gradient structure is located at the center or edge of the user facing side. Optionally, a gradient structure is arranged on the surface of the contact layer, which faces away from the user; optionally, the gradient structure comprises at least one protrusion; optionally, the gradient structure comprises at least one groove; optionally, the gradient structure is located at the center or edge of the side facing away from the user.

Drawings

Fig. 1 is a process in which a bone conduction speaker causes hearing to occur in a human ear.

Fig. 2-a is an external view of a vibration generating portion of a bone conduction speaker according to an embodiment of the present invention.

Fig. 2-B is a structural diagram of a vibration generating part of a bone conduction speaker according to an embodiment of the present invention.

Fig. 2-C is a structural diagram of a vibration generating part of a bone conduction speaker according to an embodiment of the present invention.

Fig. 3-a is an equivalent vibration model of a vibration generating part of a bone conduction speaker according to an embodiment of the present invention.

Fig. 3-B is a vibration response curve of a bone conduction speaker to which the embodiments of the present invention are applied.

Fig. 4 is a schematic diagram of a system for transmitting sound vibration by a bone conduction speaker according to an embodiment of the present invention.

Fig. 5-a and 5-B are top and side views, respectively, of a bone conduction speaker panel bonding in an embodiment of the present invention.

Fig. 6 is a structural diagram of a vibration generating part of a bone conduction speaker according to an embodiment of the present invention.

Fig. 7 is a vibration response curve of a bone conduction speaker according to an embodiment of the present invention.

Fig. 8 is a vibration response curve of a bone conduction speaker according to an embodiment of the present invention.

Fig. 9 is a structural view of a vibration generating part of a bone conduction speaker according to an embodiment of the present invention.

Fig. 10 is a frequency response curve of a bone conduction speaker according to an embodiment of the present invention.

Fig. 11 is an equivalent model of a bone conduction speaker vibration generation and delivery system in an embodiment of the present invention.

Fig. 12 is a structural diagram of a bone conduction speaker according to an embodiment of the present invention.

Fig. 13-a and 13-B are vibration response curves of a bone conduction speaker to which an embodiment of the present invention is applied.

Fig. 14-a and 14-B illustrate a method of measuring a clamping force of a bone conduction speaker according to an embodiment of the present invention.

Fig. 14-C is a vibration response curve of a bone conduction speaker to which an embodiment of the present invention is applied.

FIG. 15 illustrates one manner of adjusting the clamping force in an embodiment of the present invention.

Fig. 16-a is a schematic view of a contact surface of a vibration unit of a bone conduction speaker according to an embodiment of the present invention.

Fig. 16-B is a vibration response curve of a bone conduction speaker to which an embodiment of the present invention is applied.

Fig. 17 is a schematic view of a contact surface of a vibration unit of a bone conduction speaker according to an embodiment of the present invention.

Fig. 18-a and 18-B are structural diagrams of a bone conduction speaker and a composite vibration device thereof according to an embodiment of the present invention.

Fig. 19 is a frequency response curve of a bone conduction speaker to which the embodiment of the present invention is applied.

Fig. 20 is a structural diagram of a bone conduction speaker and a composite vibration device thereof according to an embodiment of the present invention.

Fig. 21-a is an equivalent model diagram of a vibration generating part of a bone conduction speaker according to an embodiment of the present invention.

Fig. 21-B is a vibration response curve of a bone conduction speaker suitable for use in one embodiment.

Fig. 21-C is a vibration response curve of a bone conduction speaker suitable for use in one embodiment.

Fig. 22-a is a block diagram of a vibration generating portion of a bone conduction speaker in an exemplary embodiment.

Fig. 22-B is a vibration response curve of a vibration generating portion of a bone conduction speaker in an exemplary embodiment.

Fig. 22-C is a leakage sound curve for a bone conduction speaker in one embodiment.

Fig. 23 is a block diagram of a vibration generating portion of a bone conduction speaker in an exemplary embodiment.

Fig. 24-a is an application scenario of a bone conduction speaker in an embodiment.

Fig. 24-B is a vibration response curve of a vibration generating portion of a bone conduction speaker in an exemplary embodiment.

Fig. 25 is a block diagram of a vibration generating portion of a bone conduction speaker in an exemplary embodiment.

Fig. 26 is a schematic structural diagram of a bone conduction speaker panel in an embodiment.

Fig. 27 is a gradient structure outside the contact surface of the bone conduction speaker in an embodiment.

FIGS. 28-A and 28-B are vibration response curves in specific embodiments.

Fig. 29 is a gradient structure inside the contact surface of the bone conduction speaker in an embodiment.

Fig. 30 is a block diagram of a vibration generating portion of a bone conduction speaker in an exemplary embodiment.

Detailed Description

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention and do not limit the application scope of the present invention, and it is obvious for a person skilled in the art to apply the present invention to other similar scenes according to the drawings without creative efforts.

As used in this specification and the appended claims, the terms "a," "an," "the," and/or "the" are not intended to be inclusive in the singular, but rather are intended to be inclusive in the plural, unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that steps and elements are included which are explicitly identified, that the steps and elements do not form an exclusive list, and that a method or apparatus may include other steps or elements. 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". Relevant definitions for other terms will be given in the following description.

Hereinafter, without loss of generality, in describing the bone conduction related art in the present invention, a description of "bone conduction speaker" or "bone conduction headset" will be employed. The description is merely one form of bone conduction application and it will be apparent to one of ordinary skill in the art that the "speaker" or "earpiece" may be replaced by other words of the same kind, such as "player", "hearing aid", etc. Indeed, various implementations of the invention may be readily applied to other non-speaker-type hearing devices. For example, it will be apparent to those skilled in the art that, having the benefit of the basic principles of a bone conduction speaker, various modifications and changes in form and detail may be made to the specific manner and procedure of implementing a bone conduction speaker, and in particular, the incorporation of ambient sound pickup and processing functionality into a bone conduction speaker to enable the speaker to function as a hearing aid, without departing from such principles. For example, a microphone, such as a microphone, may pick up sounds from the user/wearer's surroundings and, under certain algorithms, transmit the sound processed (or resulting electrical signal) to a bone conduction speaker portion. That is, the bone conduction speaker may be modified to incorporate a function of picking up ambient sound, and after a certain signal processing, transmit the sound to the user/wearer through the bone conduction speaker portion, thereby implementing the function of the bone conduction hearing aid. By way of example, the algorithms described herein may include one or more combinations of noise cancellation, automatic gain control, acoustic feedback suppression, wide dynamic range compression, active environment recognition, active anti-noise, directional processing, tinnitus processing, multi-channel wide dynamic range compression, active howling suppression, volume control, and the like.

Bone conduction speakers transmit sound through bones to the hearing system, thereby creating the sense of hearing. Fig. 1 is a process of generating hearing with a bone conduction speaker, which mainly includes the following steps: in step 101, a bone conduction speaker acquires or generates a signal containing sound information; in step 102, the bone conduction speaker generates vibration according to the signal; in step 103, the vibration is transmitted to the sensing terminal 104 through the transmission system. In one working scenario, a bone conduction speaker picks up or generates a signal containing sound information, converts the sound information into sound vibrations through a transducer device, and transmits the sound to a sense organ through a transmission system, ultimately hearing the sound. Without loss of generality, the subject of the hearing systems, sensory organs, etc. described above may be a human or an animal with a hearing system. It should be noted that the following description of the use of the bone conduction speaker by a human does not constitute a limitation on the use scenario of the bone conduction speaker, and similar descriptions may be applied to other animals as well.

The above description of the general flow of bone conduction speakers is merely a specific example and should not be considered the only possible embodiment. It will be obvious to those having skill in the art that, having the benefit of the teachings of the present bone conduction speaker, it is possible to embody the bone conduction speaker in the specific manner and procedure with various modifications and changes in form and detail without departing from such teachings, but such modifications and changes are intended to be within the purview of the foregoing description. For example, between the step 101 of acquiring the signal containing the sound information and the step 102 of generating the vibration, a signal modification or enhancement step may be additionally added, which may enhance or modify the signal acquired in the step 101 according to a specific algorithm or parameter. Further, between the vibration generation step 102 and the vibration transmission step 103, a vibration strengthening or correcting step may be additionally added. This step may be used to intensify or correct the vibrations generated by 102 with the sound signal of 101 or according to environmental parameters. Similarly, the vibration enhancement or modification steps may be performed between steps 103 and 104, such as noise reduction, acoustic feedback suppression, wide dynamic range compression, automatic gain control, active environment recognition, active noise immunity, directional processing, tinnitus processing, multi-channel wide dynamic range compression, active howling suppression, volume control, or the like, or any combination thereof, for the signal, and such modifications and changes are still within the scope of the claims. The methods and steps described herein may be implemented in any suitable order, or simultaneously where appropriate. In addition, individual steps may be deleted from any of the methods without departing from the spirit and scope of the subject matter described herein. Aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples without losing the effect sought.

Specifically, in step 101, the bone conduction speaker may acquire or generate a signal containing sound information according to different manners. Sound information may refer to video, audio files having a particular data format, or may refer to data or files in a general sense that can carry data that can ultimately be converted to sound through a particular means. The signal containing the sound information may come from the memory unit of the bone conduction speaker itself, or from an information generation, storage or transmission system other than the bone conduction speaker. The acoustic signals discussed herein are not limited to electrical signals and may include other forms of signals other than electrical signals, such as optical signals, magnetic signals, mechanical signals, and the like. In principle, the signal can be processed as a sound signal, as long as it contains sound information that the loudspeaker can use to generate vibrations. The sound signal is not limited to one signal source, and may be from a plurality of signal sources. These multiple signal sources may or may not be related to each other. The sound signal transmission or generation mode can be wired or wireless, and can be real-time or delayed. For example, the bone conduction speaker may receive an electrical signal containing sound information in a wired or wireless manner, or may directly obtain data from a storage medium to generate a sound signal; the bone conduction hearing aid can be added with a component with a sound collecting function, mechanical vibration of sound is converted into an electric signal by picking up sound in the environment, and the electric signal meeting specific requirements is obtained after the electric signal is processed by an amplifier. Wired connections include, but are not limited to, the use of metal cables, optical cables, or a hybrid of metal and optical cables, such as: coaxial cables, communication cables, flexible cables, spiral cables, non-metallic sheathed cables, multi-core cables, twisted pair cables, ribbon cables, shielded cables, telecommunication cables, twin cables, parallel twin wires, and twisted pairs.

The above-described examples are merely for convenience of illustration, and the medium for wired connection may be other types of transmission medium, such as other transmission medium of electrical or optical signals. Wireless connections include, but are not limited to, radio communications, free-space optical communications, acoustic communications, electromagnetic induction, and the like. Wherein the radio communication includes, but is not limited to, IEEE802.11 series of standards, IEEE802.15 series of standards (e.g., Bluetooth and ZigBee technologies, etc.), first generation mobile communication technologies, second generation mobile communication technologies (e.g., FDMA, TDMA, SDMA, CDMA, and SSMA, etc.), general packet radio service technologies, third generation mobile communication technologies (e.g., CDMA2000, WCDMA, TD-SCDMA, and WiMAX, etc.), fourth generation mobile communication technologies (e.g., TD-LTE and FDD-LTE, etc.), satellite communication (e.g., GPS technologies, etc.), Near Field Communication (NFC), and other technologies operating in ISM band (e.g., 2.4GHz, etc.); free space optical communications include, but are not limited to, visible light, infrared signals, and the like; acoustic communications include, but are not limited to, acoustic waves, ultrasonic signals, and the like; electromagnetic induction includes, but is not limited to, near field communication techniques and the like. The above examples are for convenience of illustration only, and the medium for the wireless connection may be of other types, such as Z-wave technology, other premium civilian radio bands, and military radio bands, among others. For example, as some application scenarios of the present technology, the bone conduction speaker may obtain a signal containing sound information from another device through bluetooth technology, or directly obtain data from a memory unit of the bone conduction speaker, and then generate a sound signal.

The Storage device/Storage unit includes Storage devices on a Storage system such as a Direct Attached Storage (Direct Attached Storage), a Network Attached Storage (Network Attached Storage), and a Storage Area Network (Storage Area Network). The storage device includes, but is not limited to, various common storage devices such as solid-state storage devices (solid-state disk, solid-state hybrid disk, etc.), mechanical hard disk, USB flash memory, memory stick, memory card (e.g., CF, SD, etc.), other drives (e.g., CD, DVD, HD DVD, Blu-ray, etc.), Random Access Memory (RAM), and Read Only Memory (ROM). The RAM includes but is not limited to: decimal count tubes, delay line memories, Williams tubes, Dynamic Random Access Memories (DRAMs), Static Random Access Memories (SRAMs), thyristor random access memories (T-RAMs), zero-capacitance random access memories (Z-RAMs), and the like; ROM in turn has but is not limited to: bubble memory, magnetic button wire memory, thin film memory, magnetic plated wire memory, magnetic core memory, magnetic drum memory, optical disk drive, hard disk, magnetic tape, early NVRAM (non-volatile memory), phase change memory, magnetoresistive random access memory, ferroelectric random access memory, nonvolatile SRAM, flash memory, EEPROM, erasable programmable read only memory, shielded read-stack memory, floating gate random access memory, nano-RAM, racetrack memory, variable resistive memory, and programmable metallization cells, etc. The above-mentioned storage device/storage unit is just to exemplify some examples, and the storage device that can be used by the storage device/storage unit is not limited thereto.

At 102, the bone conduction speaker may convert the signal containing the sound information into a vibration and generate a sound. The generation of vibration is accompanied by a conversion of energy, and the bone conduction speaker can use a specific transduction device to realize the conversion of a signal into mechanical vibration. The conversion process may involve the coexistence and conversion of multiple different types of energy. For example, the electrical signal may be directly converted to mechanical vibrations by a transducer device, producing sound. As another example, where sound information is contained in the light signal, a particular transducing device may effect the conversion of the light signal into a vibration signal. Other types of energy that may be co-present and converted during operation of the transducer device include thermal energy, magnetic field energy, and the like. The energy conversion method of the energy conversion device includes, but is not limited to, moving coil type, electrostatic type, piezoelectric type, moving iron type, pneumatic type, electromagnetic type, etc. The frequency response range and sound quality of bone conduction speakers can be affected by different transduction methods and the performance of various physical components in the transduction apparatus. For example, in a moving-coil transducer, a wound cylindrical coil is connected to a diaphragm, and the coil driven by a signal current drives the diaphragm to vibrate and generate sound in a magnetic field, and the expansion and contraction of the diaphragm material, the deformation, size, shape, and fixing manner of the folds, the magnetic density of a permanent magnet, and the like all have a great influence on the final sound effect quality of a bone conduction speaker. For another example, the vibrating plate may be a mirror-symmetric structure, a center-symmetric structure, or an asymmetric structure; the vibrating plate can be provided with a discontinuous hole-shaped structure, so that the vibrating plate generates larger displacement, the bone conduction loudspeaker realizes higher sensitivity, and the output power of vibration and sound is improved; for another example, the vibrating plate has a torus structure, and a plurality of struts which converge toward the center are provided in the torus, and the number of the struts may be two or more.

It is obvious to those skilled in the art that, after understanding the basic principle that the transduction mode and the specific device can affect the sound effect quality of the bone conduction speaker, it is possible to appropriately take over, combine, modify or change the above mentioned influencing factors without departing from the principle, so as to obtain the desired sound quality. For example, with a permanent magnet of high magnetic density, a better sound quality can be obtained with a more desirable material and design of the diaphragm.

The term "sound quality" as used herein is understood to reflect the quality of sound and refers to the fidelity of the audio after processing, transmission, etc. The sound quality is mainly described by three elements of loudness, tone and tone. Loudness is the subjective perception of the human ear of the intensity of a sound and is proportional to the logarithmic value of the intensity of the sound, with greater intensity of the sound being perceived as louder. But also the frequency and waveform of the sound. Tone, also known as pitch, refers to the subjective perception of the human ear of the frequency of sound vibration. The pitch depends mainly on the fundamental frequency of the sound, the higher the fundamental frequency the higher the pitch, and it is also related to the intensity of the sound. Timbre refers to the subjective perception of sound characteristics by the human ear. The timbre mainly depends on the spectral structure of the sound and is also related to factors such as the loudness, duration, building and decay processes of the sound. The spectral structure of sound is described by fundamental frequency, number of harmonics, distribution of harmonics, magnitude of amplitude, and phase relationship. Different spectral structures have different timbres. Even if the fundamental frequency and loudness are the same, the timbre is different if the harmonic structure is different.

There are many ways to achieve the vibration of the bone conduction speaker, and fig. 2-a and 2-B are block diagrams of the vibration generating part of the bone conduction speaker in one embodiment, including the housing 210, the panel 220, the transducer device 230, and the connector 240.

The vibration of the panel 220 is transmitted to the auditory nerve through the tissue and bone, thereby making the human hear the sound. The panel 220 may be in direct contact with the skin of a human body, or may be in contact with the skin through a vibration transmission layer (described in detail below) composed of a specific material. The specific material may be selected from low density materials such as plastics (e.g., but not limited to, high molecular weight polyethylene, blow-molded nylon, engineering plastics, etc.), rubbers, and other single or composite materials that achieve the same properties. For the kind of rubber, for example, but not limited to general-purpose type rubber and special-purpose type rubber. General purpose rubbers include, but are not limited to, natural rubber, isoprene rubber, styrene butadiene rubber, neoprene rubber, and the like. Specialty-type rubbers include, but are not limited to, nitrile rubber, silicone rubber, fluororubber, polysulfide rubber, urethane rubber, chlorohydrin rubber, acrylate rubber, propylene oxide rubber, and the like. Among them, the styrene-butadiene rubber includes, but is not limited to, emulsion-polymerized styrene-butadiene rubber and solution-polymerized styrene-butadiene rubber. For composite materials, reinforcing materials such as, but not limited to, glass fibers, carbon fibers, boron fibers, graphite fibers, graphene fibers, silicon carbide fibers, or aramid fibers. And may be a composite of other organic and/or inorganic materials, such as glass fiber reinforced unsaturated polyester, epoxy resin or phenolic resin matrix. Other materials that may be used to form the vibration transmitting layer include one or a combination of silicone, PolyUrethane (PolyUrethane), and polycarbonate (Poly Carbonate). The transducer device 230 is a component that converts an electrical signal into mechanical vibrations based on some principle. The panel 220 is connected to the transducer 230 and vibrates under the force of the transducer 230. Connector 240 connects faceplate 220 and housing 210 for positioning transducer assembly 230 within the housing. When the transducer 230 transmits the vibration to the panel 220, the vibration is transmitted to the housing through the connecting member 240, causing the housing 210 to vibrate, and changing the vibration mode of the panel 220 accordingly, thereby affecting the vibration transmitted by the panel 220 to the skin of the human body.

It should be noted that the manner of fixing the transducer device and the panel in the housing is not limited to the connection manner described in fig. 2-B, and it is obvious to those skilled in the art that whether the connector 240 is used, or the connector 240 made of different materials, the manner of adjusting the transducer device 230 or the panel 220 to be connected to the housing 210, etc., may exhibit different mechanical impedance characteristics, resulting in different vibration transmission effects, thereby affecting the vibration efficiency of the whole vibration system and producing different sound qualities.

For example, if a connector is not used, the panel may be directly adhered to the housing by glue, or may be connected to the housing by clipping or welding. If the connecting piece is adopted, the connecting piece with proper elastic force has a damping effect in the vibration transmission process, so that the vibration energy transmitted to the shell can be reduced, the sound leakage of the bone conduction loudspeaker to the outside caused by the shell vibration can be effectively inhibited, the abnormal sound caused by possible abnormal resonance can be avoided, and the effect of improving the tone quality can be achieved. The efficiency of the transmission of vibrations is also affected to a different extent by connections at different locations in/on the housing, which connections preferably allow the transducer device to be suspended or supported in different positions.

Fig. 2-B shows an example of a connection means, and the connection member 240 may be connected to the top end of the housing 210. Fig. 2-C illustrates another example of an attachment, in which the panel 220 extends through an opening in the enclosure 210, and the panel 220 is coupled to the transducer 230 by a coupling portion 250 and to the enclosure 210 by a coupling member 240.

In other embodiments, the transducer device may be fixed inside the housing in other connection manners, for example, the transducer device may be fixed on the inner bottom surface of the housing through a connection member, or the bottom of the transducer device (the side of the transducer device connected to the panel is the top, and the opposite side is the bottom) may be fixed inside the housing in a floating manner through a spring, or the top of the transducer device may be connected to the housing, or the transducer device and the housing may be connected through a plurality of connection members located at different positions, or any combination of the above connection manners.

In some specific embodiments, the connecting member has a certain elasticity. The elasticity of the connecting piece is determined by the material, thickness, structure and the like of the connecting piece. The material of the connecting member, such as, but not limited to, steel (e.g., but not limited to, stainless steel, carbon steel, etc.), light alloy (e.g., but not limited to, aluminum alloy, beryllium copper, magnesium alloy, titanium alloy, etc.), plastic (e.g., but not limited to, high molecular weight polyethylene, blow-molded nylon, engineering plastic, etc.), may also be other single or composite materials that can achieve the same performance. For composite materials, reinforcing materials such as, but not limited to, glass fibers, carbon fibers, boron fibers, graphite fibers, graphene fibers, silicon carbide fibers, or aramid fibers. The material constituting the connecting element can also be a composite of other organic and/or inorganic materials, such as glass fibre reinforced unsaturated polyester, epoxy resin or phenolic resin matrices of various types of glass fibre reinforced plastics. The thickness of the connecting piece is not less than 0.005mm, preferably, the thickness is 0.005mm to 3mm, more preferably, the thickness is 0.01mm to 2mm, still more preferably, the thickness is 0.01mm to 1mm, and further preferably, the thickness is 0.02mm to 0.5 mm.

The connecting piece can be configured in a ring shape, preferably comprises at least one circular ring, preferably comprises at least two circular rings, can be concentric circular rings or non-concentric circular rings, the circular rings are connected through at least two supporting rods, the supporting rods radiate from the outer ring to the center of the inner ring, further preferably comprises at least one elliptical circular ring, further preferably comprises at least two elliptical circular rings, different elliptical circular rings have different curvature radiuses, the circular rings are connected through the supporting rods, and further preferably comprises at least one square ring. The connecting piece structure can also be set into a sheet shape, preferably, hollow patterns are arranged on the sheet shape, and more preferably, the area of the hollow patterns is not less than that of the non-hollow parts of the connecting piece. It is noted that the materials, thicknesses, structures of the connectors in the above description may be combined in any way into different connectors. For example, the annular connectors may have a different thickness distribution, preferably the strut thickness is equal to the ring thickness, further preferably the strut thickness is greater than the ring thickness, further preferably the inner ring thickness is greater than the outer ring thickness.

Those skilled in the art can determine the material, position, connection mode, etc. of the connecting element according to different practical applications, or modify, improve or combine the above-mentioned different properties of the connecting element, but these modifications and improvements still fall within the scope of the above description. For example, the connectors described above are not required, and the panel may be directly mounted to the housing or may be bonded to the housing by glue. It should be noted that the shape, size, proportion, etc. of the vibration generating portion of the bone conduction speaker in practical application are not limited to those described in fig. 2A, fig. 2B, or fig. 2C, and those skilled in the art may make some changes according to the contents described in the figures while considering other factors that may affect the sound quality of the bone conduction speaker, such as the degree of sound leakage, the frequency doubling sound generated, the wearing manner, etc. of the bone conduction speaker.

Careful design and tuning of the transducer assembly and faceplate can solve many of the problems often faced by bone conduction speakers. For example, bone conduction speakers are prone to sound leakage. The term "sound leakage" as used herein means that, during operation of the bone conduction speaker, the vibration of the speaker generates sound that is transmitted to the surrounding environment, and that other persons in the environment can hear the sound emitted from the speaker in addition to the wearer of the speaker. The sound leakage phenomenon occurs due to various reasons, including that the vibration of the transducer and the panel is transmitted to the housing through the connecting member to cause the vibration of the housing, or the vibration of the transducer causes the vibration of air in the housing, and the air vibration is transmitted to the housing to cause the vibration of the housing, thereby generating the sound leakage. As shown in fig. 3-a, an equivalent vibration model of a vibration generating part of a bone conduction speaker includes a fixed end 301, a housing 311 and a panel 321, the fixed end 301 and the housing 311 are equivalently connected through an elastic body 331 and a damping member 332, and the housing 311 and the panel 321 are equivalently connected through an elastic body 341. The fixed end 301 may be a point or area where the bone conduction speaker is relatively fixed in position during vibration (described in detail below). The elastic body 331 and the damper 332 are determined by the connection mode between the earphone rack/earphone hanging band and the housing, and the influencing factors include the rigidity, shape, composition material and the like of the earphone rack/earphone hanging band and the material property of the connection part of the earphone rack/earphone hanging band and the housing. The earphone holder/earphone strap as described herein provides a pressure contact between the bone conduction speaker and the user. The elastomer 341 is determined by the connection between the panel 321 (or the system of panels and transducer) and the housing 311, and the influencing factors include the above-mentioned connection 240. The vibration equation can be expressed as:

mx″₂+Rx′₂-k₁(x₁-x₂)+k₂x₂＝0 (1)

where m is the mass of the housing 311, x₁Is the displacement, x, of the panel 321₂Displacement of the housing 311, R vibration damping, k₁Is the stiffness coefficient, k, of the elastomer 341₂Is the stiffness coefficient of the elastomer 331. In case of steady vibrations (without taking the transient response into account), the ratio x of the housing vibration to the panel vibration can be derived₂/x₁：

The ratio x of the vibration of the housing to the vibration of the panel as referred to herein₂/x₁The size of the leakage sound of the bone conduction loudspeaker can be reflected. In general, x₂/x₁A larger value of (a) indicates a larger vibration of the housing compared to the effective vibration transmitted to the hearing system, and a larger sound leakage at the same volume; x is the number of₂/x₁The smaller the value of (A), the vibration of the housing is compared with the vibration transmitted to the hearingThe smaller the effective vibration of the force system, the smaller the sound leakage at the same volume. It can be seen that the factors influencing the sound leakage of the bone conduction speaker include the connection between the panel 321 (or the system of the panel and the transducer) and the housing 311 (the stiffness coefficient k of the elastomer 341)₁) Earphone rack/earphone strap and housing system (k)₂R, m), etc. In one embodiment, the stiffness coefficient k of the elastomer 331₁The housing mass m and the damping R are dependent on the shape and the manner of mounting of the loudspeaker, at k₁M, after R is determined, x₂/x₁And stiffness coefficient k of elastomer 341₁The relationship between them is shown in fig. 3-B. As can be seen from the figure, the different stiffness coefficients k₁The ratio of the amplitude of the vibration of the housing to the amplitude of the vibration of the panel, i.e. x, is influenced₂/x₁. When the frequency f is greater than 200Hz, the vibration of the housing is less than the vibration (x) of the panel₂/x₁<1) And the vibration of the housing becomes gradually smaller as the frequency increases. In particular, as shown in FIG. 3-B, for different k₁Value of (k is a stiffness coefficient set from left to right in this order)₂5 times, 10 times, 20 times, 40 times, 80 times, and 160 times) of the frequency of the panel, the enclosure vibration is already less than 1/10 (x) of the panel vibration when the frequency is greater than 400Hz₂/x₁<0.1). In a particular embodiment, the stiffness coefficient k is reduced₁The value of (e.g., the stiffness factor of the connector 240 is selected to be small) is effective to reduce vibration of the housing and thereby reduce sound leakage.

In particular embodiments, the use of a particular material and connection means of the connector may reduce sound leakage. For example, the panel, the transducer and the shell are connected by adopting a connecting piece with certain elasticity, so that the vibration amplitude of the shell is smaller under the condition that the panel vibrates at a larger amplitude, and the sound leakage is reduced. There are many materials that can be used to make the connector, including, but not limited to, stainless steel, beryllium copper, plastic (e.g., polycarbonate), and the like. The shape of the connecting element can be arranged in a wide variety of ways. For example, the connecting member may be a torus having at least two struts converging toward the center, the thickness of the torus being not less than 0.005mm, preferably, the thickness is from 0.005mm to 3mm, more preferably, the thickness is from 0.01mm to 2mm, still more preferably, the thickness is from 0.01mm to 1mm, and still more preferably, the thickness is from 0.02mm to 0.5 mm. In another example, the connecting member may be a circular ring, and the circular ring may further have a plurality of discontinuous ring holes, and each ring hole may have a discontinuous interval therebetween. For another example, a certain number of sound-guiding holes satisfying a certain condition may be formed in the housing or the panel (or a vibration transmission layer on the outer side of the panel, which will be described in detail later), so that sound wave vibration in the housing can be guided and propagated to the outside of the housing during the vibration process of the transducer apparatus, and interact with sound leakage waves formed by the vibration of the housing, thereby achieving the effect of suppressing sound leakage of the bone conduction speaker. As another example, a housing of sound absorbing material may be selected or sound absorbing material may be used over at least a portion of the housing. The sound absorbing material may be applied to one or more of the inner/outer surfaces of the housing or may be a portion of the area of one of the inner/outer surfaces of the housing. A sound absorbing material refers to a material that has the effect of absorbing incident sound energy by one or more of the physical properties of the material itself (e.g., without limitation, porosity), membrane action, resonance action. In particular, the sound absorbing material may be a porous material or a material having a porous structure, including, but not limited to, an organic fiber material (such as, but not limited to, natural plant fibers, organic synthetic fibers, etc.), an inorganic fiber material (such as, but not limited to, glass wool, slag wool, aluminum silicate wool, rock wool, etc.), a metal sound absorbing material (such as, but not limited to, a metal fiber sound absorbing panel, a foamed metal material, etc.), a rubber sound absorbing material, a foamed plastic sound absorbing material (such as, but not limited to, polyurethane foam, polyvinyl chloride foam, polyacrylate polystyrene foam, phenolic resin foam, etc.), etc.; flexible materials that absorb sound by resonance are also possible, including but not limited to closed cell foams; film-like materials including, but not limited to, plastic films, cloth, canvas, varnished cloth, or artificial leather; the plate material includes, but is not limited to, for example, a hardboard, a gypsum board, a plastic board, a metal plate) or a perforated plate (e.g., made by perforating the plate material). The sound absorbing material may be one or a combination of more than one, or may be a composite material. The sound absorbing material may be provided on the housing or on the vibration transmission layer or the housing of the vibration housing, respectively.

The housing, the vibration transmission layer, and the panel bonded to the vibration transmission layer described herein together constitute a vibration unit of the bone conduction speaker. The transducer means is located in the vibration unit and transmits vibrations to the vibration unit through the connection with the panel and the housing. Preferably, at least more than 1% of the vibration unit is sound absorbing material, more preferably at least more than 5% of the vibration unit is sound absorbing material, and even more preferably at least more than 10% of the vibration unit is sound absorbing material. Preferably, at least more than 5% of the casing is sound absorbing material, more preferably at least more than 10% of the casing is sound absorbing material, even more preferably more than 40% of the casing is sound absorbing material, even more preferably at least more than 80% of the casing is sound absorbing material. In a further embodiment, a compensation circuit may be introduced to actively control the phase of the leakage sound to generate an inverted signal in phase opposition to the leakage sound, thereby suppressing the leakage sound, depending on the nature of the leakage sound. It should be noted that the above-described ways of changing the sound quality of the bone conduction speaker may be used alternatively or in combination to obtain various embodiments, which are also within the scope of the present invention.

The above description of the structure of the vibration generating part of the bone conduction speaker is merely a specific example and should not be considered as the only possible embodiment. It will be apparent to those skilled in the art that, having the benefit of this general teaching, numerous modifications and variations can be made in the specific constructions and arrangements of parts which will carry out this vibration without departing from the general teaching, but these modifications and variations are within the scope of the invention as defined in the foregoing description. For example, attachment portion 250 in FIGS. 2-B, 2-C may be a portion of panel 220 that is adhesively bonded to transducer assembly 230; or may be a portion of the transducer assembly 230 (e.g., a raised portion on the vibrating plate) that is glued to the panel 220; or may be a separate component that is glued to both the faceplate 220 and the transducer assembly 230. Of course, the connection between the connection portion 250 and the panel 220 or the transducer 230 is not limited to bonding, and other connections known to those skilled in the art may be suitable for the present invention, such as clamping or welding. Preferably, the panel 220 and the housing 210 are directly adhered by glue, more preferably, they are connected by a component similar to the elastic member 240, and further preferably, they are connected to the housing 210 by adding a vibration transmission layer (described in detail later) on the outer side of the panel 220. It should be noted that the connecting portion 250 is a schematic diagram illustrating the connection between different components, and those skilled in the art may substitute components having similar functions and different shapes, and these substitutions and changes are still within the scope of protection described above.

At step 103, sound is delivered to the hearing system via the delivery system. The transmission system can transmit the sound vibration to the hearing system directly through a medium, or can transmit the sound vibration to the hearing system after certain processing in the sound transmission process.

Fig. 4 shows an embodiment of a sound transmission system, in which a bone conduction speaker 401 is in contact with the back of the ear, cheek, or forehead, and transmits sound vibration to the skin 402, subcutaneous tissue 403, bone 404 to cochlea 405, and finally to the brain via the cochlear auditory nerve. The sound quality experienced by the human body is influenced by the transmission medium and other factors affecting the physical properties of the transmission medium. For example, the density and thickness of the skin and subcutaneous tissue, the shape and density of the bone, and other tissues of the human body through which vibrations may pass during transmission all contribute to the final sound quality. Further, in the transmission process of vibration, the vibration transmission efficiency of the bone conduction speaker and the human tissue in the contact part can also affect the final sound effect.

For example, the bone conduction speaker panel transmits vibrations through human tissue to the human hearing system, and changes in the material, contact area, shape and/or size of the panel and the interaction force between the panel and the skin can affect the efficiency of sound transmission through the medium, and thus affect the sound quality. For exampleUnder the same driving, the vibration transmitted by the panels with different sizes is distributed on the binding surface of the wearer in different ways, and then the difference between the volume and the tone quality can be brought. Preferably, the area of the panel is not less than 0.15cm²More preferably, the area is not less than 0.5cm²Further preferably, the area is not less than 2cm². For another example, the panel is vibrated by the transducer device, the bonding point between the panel and the transducer device is at the center of the panel vibration, preferably, the mass distribution of the panel around the vibration center is uniform (i.e., the vibration center is the physical center of the panel), and more preferably, the mass distribution of the panel around the vibration is not uniform (i.e., the vibration center is offset from the physical center of the panel). For example, one vibration plate may be connected to a plurality of panels, the plurality of panels may be identical or different in shape and material from each other, or may be connected or disconnected from each other, the plurality of panels transmit sound vibrations through a plurality of paths, the vibration transmission modes between different paths are different from each other, the positions of the vibrations transmitted to the panels are different, and the vibration signals between different panels may be complementary to each other, thereby generating a relatively flat frequency response. For another example, dividing one vibrating plate with a large area into two or more vibrating plates with a small area can effectively improve the uneven vibration caused by the deformation of the panel at high frequency, and make the frequency response more ideal.

It is noted that the physical properties of the panel, such as mass, size, shape, stiffness, vibration damping, etc., all affect the efficiency of the panel vibration. The panel made of a suitable material may be selected by those skilled in the art according to actual needs, or the panel may be injection molded into different shapes by using different molds, preferably, the shape of the panel may be configured as a rectangle, a circle or an ellipse, more preferably, the shape of the panel may be a figure obtained by cutting edges of the rectangle, the circle or the ellipse (for example, but not limited to, a circular symmetry is cut to obtain a shape similar to an ellipse, etc.), and further preferably, the panel may be configured as a hollow. The panel material includes, but is not limited to, Acrylonitrile-butadiene-styrene (Acrylonitrile butadiene styrene, ABS), Polystyrene (Polystyrene, PS), High Impact Polystyrene (HIPS), Polypropylene (PP), Polyethylene terephthalate (PET), Polyester (PES), Polycarbonate (PC), Polyamide (PA), Polyvinyl chloride (PVC), Polyurethane (PU), Polyvinyl dichloride (Polyvinylidene chloride), Polyethylene (PE), Polymethyl methacrylate (PMMA), polyether ether ketone (PEEK), phenolic resin (phenol, PF), Urea-formaldehyde (Urea-formaldehyde), Melamine-formaldehyde (UF), aluminum alloy (MF), Melamine-formaldehyde alloy (MF), and Melamine-formaldehyde alloy (MF), such as Melamine-formaldehyde alloy (Melamine-formaldehyde alloy), Melamine-formaldehyde alloy (MF), and Melamine-formaldehyde alloy (Melamine-formaldehyde alloy), and Melamine-formaldehyde alloy (Melamine formaldehyde alloy (PMMA) Titanium alloy, magnesium-lithium alloy, nickel alloy, etc.) or composite materials, etc. Relevant parameters include the relative density, tensile strength, modulus of elasticity, rockwell hardness, etc. of the material. Preferably, the panel material has a relative density of 1.02 to 1.50, more preferably a relative density of 1.14 to 1.45, and even more preferably a relative density of 1.15 to 1.20. The tensile strength of the panel is not less than 30MPa, more preferably, the tensile strength is 33MPa to 52MPa, and further preferably, the tensile strength is not less than 60 MPa. The panel material may have a modulus of elasticity in the range of 1.0GPa to 5.0GPa, more preferably a modulus of elasticity in the range of 1.4GPa to 3.0GPa, and even more preferably a modulus of elasticity in the range of 1.8GPa to 2.5 GPa. Similarly, the hardness (Rockwell hardness) of the panel material may be 60 to 150, more preferably, the hardness may be 80 to 120, and still more preferably, the hardness may be 90 to 100. Particularly, the panel material and the tensile strength are considered together, and may be a relative density of 1.02 to 1.1 and a tensile strength of 33MPa to 52MPa, and more preferably, the panel material has a relative density of 1.20 to 1.45 and a tensile strength of 56 MPa to 66 MPa.

In other embodiments, the bone conduction speaker has a vibration transmission layer wrapped around the outer side of the faceplate, the vibration transmission layer is in contact with the skin, and the vibration system formed by the faceplate and the vibration transmission layer transmits the generated sound vibration to the human tissue. Preferably, the outer side of the panel is wrapped by one vibration transmission layer, and more preferably, the outer side of the panel is wrapped by a plurality of vibration transmission layers; the vibration transmission layer may be composed of one or moreThe materials of the different vibration transmission layers can be the same or different; the plurality of vibration transmission layers may be stacked on each other in a direction perpendicular to the panel, may be arranged in a state of being laid out in a direction horizontal to the panel, or may be a combination of the two arrangements. The area of the vibration transfer layer may be set to various sizes, and preferably, the area of the vibration transfer layer is not less than 1cm²More preferably, the area of the vibration transfer layer is not less than 2cm²Further preferably, the area of the vibration transfer layer is not less than 6cm²。

The vibration transmission layer can be made of a material with certain adsorbability, flexibility and chemical property, such as plastic (for example, but not limited to, high-molecular polyethylene, blow-molded nylon, engineering plastic and the like), rubber, or other single or composite materials capable of achieving the same performance. For the kind of rubber, for example, but not limited to general-purpose type rubber and special-purpose type rubber. General purpose rubbers include, but are not limited to, natural rubber, isoprene rubber, styrene butadiene rubber, neoprene rubber, and the like. Specialty-type rubbers include, but are not limited to, nitrile rubber, silicone rubber, fluororubber, polysulfide rubber, urethane rubber, chlorohydrin rubber, acrylate rubber, propylene oxide rubber, and the like. Among them, the styrene-butadiene rubber includes, but is not limited to, emulsion-polymerized styrene-butadiene rubber and solution-polymerized styrene-butadiene rubber. For composite materials, reinforcing materials such as, but not limited to, glass fibers, carbon fibers, boron fibers, graphite fibers, graphene fibers, silicon carbide fibers, or aramid fibers. And may be a composite of other organic and/or inorganic materials, such as glass fiber reinforced unsaturated polyester, epoxy resin or phenolic resin matrix. Other materials that may be used to form the vibration transmitting layer include one or a combination of silicone, polyurethane (Poly Urethane), and PolyCarbonate (Poly carbonate).

The existence of the vibration transmission layer can affect the frequency response of the system, change the tone quality of the bone conduction loudspeaker and simultaneously play a role in protecting elements in the shell. For example, the vibration transmission layer can change the vibration mode of the panel, so that the frequency response of the whole system is smoother. The vibration mode of the panel is affected by factors such as the properties of the panel itself, the connection mode between the panel and the vibration plate, the connection mode between the panel and the vibration transmission layer, the vibration frequency, and the like. The panel's own properties include, but are not limited to, the mass, size, shape, stiffness, vibration damping, etc. of the panel. Preferably, a panel of non-uniform thickness (e.g., without limitation, a panel having a center thickness greater than an edge thickness) may be used. The connection mode of the panel and the vibrating plate includes but is not limited to glue bonding, clamping or welding and the like; the attachment of the panel and the vibration transfer layer includes, but is not limited to, glue attachment; different vibration frequencies can correspond to different vibration modes of the panel, including the integral translation and the torsion translation of different degrees of the panel, and the tone quality of the bone conduction loudspeaker can be changed by selecting the panel with the specific vibration mode in a specific frequency range. Preferably, the specific frequency range referred to herein may be 20Hz-20000Hz, more preferably, the frequency range may be 400Hz-10000Hz, further preferably, the frequency range may be 500Hz-2000Hz, still further preferably, the frequency range may be 800Hz-1500 Hz.

Preferably, the vibration transfer layer described above is wrapped around the outside of the panel, constituting one side of the vibration unit. Different areas on the vibration transmission layer have different vibration transmission effects. For example, there are a first contact surface area and a second contact surface area on the vibration transfer layer, preferably the first contact surface area does not abut the panel and the second contact surface area abuts the panel; more preferably, the clamping force on the first contact surface area is smaller than the clamping force on the second contact surface area when the vibration transfer layer is in direct or indirect contact with the user (where clamping force refers to the pressure between the contact surface of the vibration unit and the user); further preferably, the first contact surface area is not in direct contact with the user, and the second contact surface area is in direct contact with the user and transmits the vibrations. The area of the first contact surface area and the area of the second contact surface area are different in size, preferably, the area of the first contact surface area is smaller than that of the second contact surface area, more preferably, the first contact surface area is provided with small holes, and the area of the first contact area is further reduced; the outer surface of the vibration transfer layer (i.e. the user facing surface) may or may not be flat, preferably the first contact surface area and the second contact surface area are not in the same plane; more preferably, the second contact surface area is higher than the first contact surface area; further preferably, the second contact surface region and the first contact surface region constitute a step structure; still further preferably, the second contact surface area is in contact with the user and the first contact surface area is not in contact with the user. The constituent materials of the first interface region and the second interface region may be the same or different, and may be a combination of one or more of the vibration transfer layer materials described above. The above description of the clamping force on the contact surfaces is only one manifestation of the present invention, and the structure and manner of the above description may be modified as needed by those skilled in the art while remaining within the scope of the present invention. For example, the vibration transfer layer may not be necessary, the panel may be in direct contact with the user, and different interface regions may be provided on the panel, the different interface regions possessing similar properties to the first and second interface regions described above. For another example, a third contact surface region may be provided on the contact surface, and a structure different from the first contact surface region and the second contact surface region may be provided on the third contact surface region, and these structures can achieve certain effects in terms of reducing the housing vibration, suppressing the leakage sound, improving the frequency response curve of the vibration unit, and the like.

As a specific example, fig. 5-a and 5-B are front and side views, respectively, of the connection of the faceplate to the vibration transmission layer. The panel 501 and the vibration transmission layer 503 are bonded by glue 502, the glue bonding positions are located at two ends of the panel 501, and the panel 501 is located in a shell formed by the vibration transmission layer 503 and the shell 504. Preferably, the projection of the panel 501 on the vibration transfer layer 503 is a second contact surface area, and the area located around the second contact surface area is the first contact surface area.

Glue can be adopted for completely sticking the panel and the vibration transmission layer, so that the quality, size, shape, rigidity, vibration damping, vibration mode and other properties of the panel are equivalently changed, and the vibration transmission efficiency is higher; the panel and the transmission layer can be partially bonded by only using glue, so that a non-bonding area between the panel and the transmission layer has gas conduction, the transmission of low-frequency vibration can be enhanced, and the low-frequency effect in sound is improved, preferably, the glue area accounts for 1% -98% of the panel area, more preferably, the glue area accounts for 5% -90% of the panel area, still more preferably, the glue area accounts for 10% -60% of the panel area, and still more preferably, the glue area accounts for 20% -40% of the panel area; the panel and the transmission layer can be bonded without glue, so that the vibration transmission efficiency of the panel and the transmission layer is different from the condition of bonding by using glue, and the tone quality of the bone conduction loudspeaker can be changed. In a specific embodiment, changing the way the glue is applied can change the way the corresponding components in the bone conduction speaker vibrate, thereby changing the sound production and transmission effect. Further, the properties of the glue also affect the sound quality of the bone conduction speaker, such as the hardness, shear strength, tensile strength, and ductility of the glue. For example, preferably, the tensile strength of the glue is not less than 1MPa, more preferably, the tensile strength is not less than 2MPa, and further preferably, the tensile strength is not less than 5 MPa; preferably, the elongation at break of the glue is 100% -500%, more preferably, the elongation at break is 200% -400%; preferably, the shear strength of the glue is not less than 2MPa, more preferably, the shear strength is not less than 3 MPa; preferably, the shore hardness of the glue is 25-30, more preferably 30-50. One glue may be used or a combination of glues of different properties may be used. The bonding strength between the glue and the panel and between the glue and the plastic may also be set within a certain range, such as, but not limited to, 8MPa-14 MPa. It should be noted that the vibration transmission layer material in the embodiment is not limited to silicon gel, but plastic, biological material or other material with certain adsorptivity, flexibility and chemical property can also be used. The person skilled in the art can also decide the type and properties of the glue, the material of the panel bonded with the glue and the material of the vibration transmission layer according to the actual needs, and to a certain extent, the sound quality of the bone conduction speaker.

Fig. 6 is a specific example of the manner in which the components in the vibration generating portion of the bone conduction speaker are connected. The transducer device 610 is attached to the housing 620, the faceplate 630 is bonded to the vibration transfer layer 640 by glue 650, and the edges of the vibration transfer layer 640 are attached to the housing 620. In different embodiments, the frequency response of the bone conduction speaker can be changed by changing the distribution, hardness or amount of glue 650, or changing the hardness of the transmission layer 640, etc., thereby changing the sound quality. Preferably, glue is not coated between the panel and the vibration transmission layer, more preferably, glue is coated between the panel and the vibration transmission layer, further preferably, glue is coated on a partial area between the panel and the vibration transmission layer, and still further preferably, the area of the glue coated area between the panel and the vibration transmission layer is not larger than the area of the panel.

The amount of glue can be decided according to actual need by those skilled in the art, so as to achieve the effect of adjusting the tone quality of the loudspeaker. As shown in fig. 7, in one embodiment, the effect of different glue connections on the frequency response of the bone conduction speaker is reflected. The three curves respectively correspond to the frequency response when no vibration transmission layer and glue are coated, glue is not coated between the vibration transmission layer and the panel, and glue is coated between the vibration transmission layer and the panel. It can be seen that the resonant frequency of the bone conduction speaker shifts to a low frequency when a small amount of glue or no glue is applied between the vibration transmission layer and the panel, relative to the case of full glue. The influence of the vibration transmission layer on the vibration system can be reflected by the bonding condition of glue between the vibration transmission layer and the panel. Therefore, the frequency response curve of the bone conduction loudspeaker can be obviously changed by changing the bonding mode of the glue.

Workers in the field can adjust and improve the bonding mode and the quantity of the glue according to the actual frequency response requirement, so that the sound quality of the system is improved. Similarly, in another embodiment, FIG. 8 reflects the effect of stiffness of different vibration transfer layers on the vibration response curve. The solid line is the vibration response curve for a bone conduction speaker using a harder transmission layer and the dashed line is the vibration response curve for a bone conduction speaker using a softer transmission layer. It can be seen that the use of vibration transmitting layers of different stiffness allows the bone conduction speaker to achieve different frequency responses. The higher the hardness of the vibration transmission layer is, the stronger the capability of transmitting high-frequency vibration is; the smaller the hardness of the vibration transmission layer, the stronger the ability to transmit low-frequency vibrations. Different sound qualities can be obtained by selecting vibration transmission layers of different materials (not limited to silicone, plastic, etc.). For example, a vibration transmission layer made of 45-degree silica gel on the bone conduction speaker can obtain a good bass effect, and a vibration transmission layer made of 75-degree silica gel can obtain a good treble effect. As used herein, low frequency refers to sounds below 500Hz, mid frequency refers to sounds in the range of 500Hz to 4000Hz, and high frequency refers to sounds above 4000 Hz.

Of course, the above description of glue and vibration transfer layer is only one example that may affect the sound quality of a bone conduction speaker and should not be considered the only possible embodiment. It is obvious to those skilled in the art that, after understanding the basic principle affecting the sound quality of the bone conduction speaker, it is possible to make adjustments and changes to the individual components and connections of the vibration generating part of the bone conduction speaker without departing from this principle, but these adjustments and changes are still within the scope of protection described above. For example, the material of the vibration transmission layer may be arbitrary or customized according to the usage habit of the user. The use of glue between the vibration transfer layer and the face plate, which after curing has different hardness, may also have an impact on the sound quality of the bone conduction speaker. In addition, increasing the thickness of the vibration transfer layer may be equivalent to increasing the mass in the constituent vibration system, and may also have the effect of decreasing the resonant frequency of the system. Preferably, the transfer layer has a thickness of 0.1mm to 10mm, more preferably a thickness of 0.3mm to 5mm, still more preferably a thickness of 0.5mm to 3mm, and even more preferably a thickness of 1mm to 2 mm. The tensile strength, viscosity, hardness, tear strength, elongation, etc. of the transfer layer also affect the sound quality of the system. The tensile strength of the material of the transfer layer means a force per unit area required to cause tearing of a sample of the transfer layer, and preferably, the tensile strength is 3.0MPa to 13MPa, more preferably, the tensile strength is 4.0MPa to 12.5MPa, and further preferably, the tensile strength is 8.7MPa to 12 MPa. Preferably, the transfer layer has a shore hardness of 5-90, more preferably 10-80, and even more preferably 20-60. The elongation of the transfer layer refers to the percentage of increase in the relative to the original length at break of the transfer layer, preferably the elongation is between 90% and 1200%, more preferably the elongation is between 160% and 700%, and even more preferably the elongation is between 300% and 900%. The tear strength of the transfer layer refers to the resistance against propagation of the incision or score when a force is exerted on the transfer layer with an incision, preferably the tear strength is between 7kN/m and 70kN/m, more preferably the tear strength is between 11kN/m and 55kN/m, and even more preferably the tear strength is between 17kN/m and 47 kN/m.

In the vibration system composed of the panel and the vibration transmission layer described above, in addition to changing the physical properties of the panel and the transmission layer, and the manner of bonding the panel and the vibration transmission layer, the performance of the bone conduction speaker can be changed from other aspects.

A well-designed vibration generating section including a vibration transmitting layer can further effectively reduce the bone conduction speaker leakage sound. Preferably, the vibration transmission layer is perforated to reduce sound leakage. In one embodiment, as shown in FIG. 9, vibration transfer layer 940 is bonded to panel 930 by glue 950, the bonding area of the vibration transfer layer to the panel is raised higher than the non-bonding area of vibration transfer layer 940, and a cavity is formed below the non-bonding area. The non-adhesive region of the vibration transmission layer 940 and the surface of the housing 920 are respectively provided with sound leading holes 960. Preferably, the non-adhesive area where part of the sound-introducing hole is opened is not in contact with the user. On one hand, the sound-leading hole 960 can effectively reduce the area of the non-bonding area on the vibration transmission layer 940, so that the air inside and outside the vibration transmission layer is permeable, and the difference between the air pressure inside and outside is reduced, thereby reducing the vibration of the non-bonding area; on the other hand, the sound guide holes 960 may guide sound waves formed by the vibration of the air inside the case 920 to the outside of the case 920 to cancel sound leakage waves formed by the vibration of the case 920 pushing the air outside the case, thereby reducing the amplitude of the sound leakage waves. Specifically, the sound leakage of the bone conduction speaker at any point in space is proportional to the sound pressure P at that point,

wherein,

P＝P₀+P₁+P₂ (3)

P₀is the sound pressure, P, generated by the housing (including the portion of the vibration transmission layer not in contact with the skin) at the point mentioned above₁Is the sound pressure, P, of the sound transmitted from the sound-introducing hole in the side of the casing at the point₂Is the sound pressure, P, of the sound transmitted from the sound-introducing hole in the vibration transmission layer at the point₀、P₁、P₂The method comprises the following steps:

where k denotes the wave vector ρ₀Representing the air density, ω representing the angular frequency of vibration, R (x ', y') representing the distance from a point on the sound source to a point in space, S₀Is the area of the shell not in contact with the human face, S₁Is the open pore area of the sound leading hole on the side surface of the shell, S₂Is an open pore area of a sound introducing hole in the vibration transfer layer, W (x, y) represents the intensity of a sound source per unit area,representing the phase difference of sound pressures generated by different sound sources at a point in space. It is noted that there are partial areas of the vibration transfer layer that are not in contact with the skin (e.g., the edge areas where the sound-introducing holes 960 are located on the vibration transfer layer 940 in fig. 9), which are subject to panel and housing vibrationThe above-mentioned housing area should contain such parts of the vibration transmission layer that are not in contact with the skin, thereby generating vibrations and thus radiating sound to the outside. The sound pressure (at an angular frequency ω) at any point in space can be expressed as:

the aim is to reduce the value of P as much as possible, thereby achieving the effect of reducing the noise leakage. In practical use, the coefficients A1 and A2 can be adjusted by adjusting the size and the number of the sound leading holes, and the phase can be adjusted by adjusting the positions of the sound leading holesThe value of (a). After understanding the principle that the sound quality of the bone conduction speaker is affected by a vibration system consisting of the panel, the transducer, the vibration transmission layer and the shell, a person skilled in the art can adjust the shape, the opening position, the number, the size, the damping on the holes and the like of the sound-leading holes according to actual needs, thereby achieving the purpose of inhibiting sound leakage. For example, the sound-introducing hole may be one or more, preferably a plurality of. For the sound-guiding holes annularly arranged on the side surface of the shell, the number of the sound-guiding holes in each arrangement area can be one or more, for example, 4-8. The shape of the sound leading hole can be round, oval, rectangular or long strip. The sound-guiding holes on one bone conduction loudspeaker can adopt sound-guiding holes with the same shape, and can also adopt the combination of sound-guiding holes with various different shapes. For example, the vibration transmission layer and the side surface of the shell are respectively provided with sound leading holes with different shapes and numbers, and the number density of the sound leading holes on the vibration transmission layer is greater than that of the sound leading holes on the side surface of the shell. For example, by providing a plurality of small holes in the vibration transmission layer, the area of the portion of the vibration transmission layer not in contact with the skin can be effectively reduced, and the noise leakage generated from this portion can be reduced. For another example, damping material or sound absorbing material is added to the sound-guiding holes on the side of the vibration transmission layer/casing, so that the purpose of suppressing sound leakage can be further enhanced. Further, the sound-introducing hole may be expanded to facilitate the housingThe air vibrations inside are conducted out of the material or structure of the housing. For example, phase adjusting materials (such as, but not limited to, sound absorbing materials) are used as part of the material of the housing to conduct air vibrations out of a phase range of 90 ° to 270 ° with the other parts of the housing, thereby acting as sound cancellation. Description of the sound-introducing holes for housing layout appears in chinese patent application No. 201410005804.0 filed 1/6 2014 entitled "a method for suppressing sound leakage of bone conduction speaker and bone conduction speaker", which is incorporated herein by reference in its entirety. Furthermore, the connection mode between the transducer device and the shell can be adjusted to change the phase of the vibration of other parts of the shell, and the phase difference between the vibration and the sound transmitted from the sound guide hole is in the range of 90-270 degrees, so that the sound cancellation effect is achieved. For example, the transducer device and the housing may be made of an elastic connecting member, and the material of the connecting member, such as, but not limited to, steel (e.g., but not limited to, stainless steel, carbon steel, etc.), light alloy (e.g., but not limited to, aluminum alloy, beryllium copper, magnesium alloy, titanium alloy, etc.), plastic (e.g., but not limited to, high molecular weight polyethylene, blow-molded nylon, engineering plastic, etc.), or other single or composite materials capable of achieving the same performance may be used. For composite materials, reinforcing materials such as, but not limited to, glass fibers, carbon fibers, boron fibers, graphite fibers, graphene fibers, silicon carbide fibers, or aramid fibers. The material constituting the connecting element can also be a composite of other organic and/or inorganic materials, such as glass fibre reinforced unsaturated polyester, epoxy resin or phenolic resin matrices of various types of glass fibre reinforced plastics. The thickness of the connecting piece is not less than 0.005mm, preferably, the thickness is 0.005mm to 3mm, more preferably, the thickness is 0.01mm to 2mm, still more preferably, the thickness is 0.01mm to 1mm, and further preferably, the thickness is 0.02mm to 0.5 mm. The connecting piece can be configured in a ring shape, preferably comprises at least one circular ring, preferably comprises at least two circular rings, can be concentric circular rings or non-concentric circular rings, the circular rings are connected through at least two supporting rods, the supporting rods radiate from the outer ring to the center of the inner ring, further preferably comprises at least one elliptical circular ring, further preferably comprises at least two elliptical circular ringsThe rings, different elliptical rings having different radii of curvature, are connected by struts, and more preferably comprise at least one square ring. The connecting piece structure can also be set into a sheet shape, preferably, hollow patterns are arranged on the sheet shape, and more preferably, the area of the hollow patterns is not less than that of the non-hollow parts of the connecting piece. It is noted that the materials, thicknesses, structures of the connectors in the above description may be combined in any way into different connectors. For example, the annular connectors may have a different thickness distribution, preferably the strut thickness is equal to the ring thickness, further preferably the strut thickness is greater than the ring thickness, further preferably the inner ring thickness is greater than the outer ring thickness.

The above description of the sound-absorbing holes is an example of the present invention and does not constitute a limitation on the bone conduction speaker in terms of improving sound quality, suppressing sound leakage, etc., and the inventors of the present invention may make various modifications and improvements to the above-described embodiment, which modifications and improvements still fall within the above-described protection scope. For example, it is preferable that the sound-introducing hole is opened only in the vibration transmission layer, more preferably, the sound-introducing hole is opened only in a region where the vibration transmission layer does not coincide with the panel, further preferably, the sound-introducing hole is opened in a region where it does not contact with the user, and further preferably, the sound-introducing hole is opened in a cavity inside the vibration unit. For another example, the sound-guiding holes may also be provided in the bottom wall of the housing, and the number of the sound-guiding holes provided in the bottom wall may be one, provided in the center of the bottom wall, or multiple, and arranged to be uniformly distributed circumferentially in an annular shape around the center of the bottom wall. For another example, the sound-guiding holes may be formed in the side wall of the housing, and the number of the sound-guiding holes formed in the side wall of the housing may be one or more, and the sound-guiding holes are circumferentially and uniformly distributed.

The above description of vibration transmission for a bone conduction speaker is merely a specific example and should not be considered the only possible embodiment. It will be apparent to those skilled in the art that, having the benefit of the teachings of the bone conduction speaker, various modifications and changes in form and detail may be made to the vibration description of the bone conduction speaker without departing from such principles, but such modifications and changes are intended to be within the scope of the foregoing description. For example, an implantable bone conduction hearing aid can be directly attached to a bone of a human body to directly transmit sound vibration to the bone without passing through skin or subcutaneous tissue, so that attenuation and change of frequency response caused by the skin or the subcutaneous tissue during vibration transmission can be avoided to a certain extent. As another example, in some applications, the conduction site may be a tooth, i.e., the bone conduction device may be attached to the tooth to transmit acoustic vibrations through the tooth to the bone and surrounding tissue, and may also reduce to some extent the effect of the skin on the frequency response during vibration. The above description of the application scenario of bone conduction is for illustrative purposes only, and those skilled in the art can apply the bone conduction technology to different scenarios in which the transmission of sound can be part of the changes to the transmission path described above after understanding the basic principle of bone conduction, and the changes still fall within the scope of protection described above.

The perceived quality of sound is also related to the hearing system of the human body, and different people may have different sensitivity to sounds in different frequency ranges, step 104. In some embodiments, the sensitivity of the human body to sounds of different frequencies may be reflected by an equal loudness curve. Some people, who are not sensitive to sound in a specific frequency range in the sound signal, show a lower response intensity at the equal loudness curve for the corresponding frequency than in other frequencies. For example, some people are insensitive to high frequency sound signals, i.e., appear on the equal loudness curve as intensity responses at corresponding high frequency signals are lower than intensity responses at other frequencies; some people are insensitive to mid-low frequency sound signals and appear on the equal loudness curve as intensity responses at corresponding mid-low frequency signals are lower than those at other frequencies. As used herein, low frequency refers to sounds below 500Hz, mid frequency refers to sounds in the range of 500Hz to 4000Hz, and high frequency refers to sounds above 4000 Hz.

Of course, the low frequency and the high frequency of the sound may be opposite, and the distribution of the sound intensity generated by the bone conduction speaker in the corresponding frequency range is selectively changed or adjusted according to the different responses of the hearing system of some special people to the sounds in different frequency ranges, so that the corresponding people can obtain different sound experiences. It is noted that the high, mid, or low frequency portions of the sound signal discussed above may be a description of the corresponding portions in the hearing range of a normal human ear, or may be a description of the corresponding portions in the sound range of nature that the speaker is intended to express.

In one embodiment, the equal loudness contours of the hearing system of some people, as shown in curve 3 of fig. 10, have peaks around the frequency at point a, indicating that the people are more sensitive to sounds at frequencies around point a than at other frequencies (e.g., point B). When designing a bone conduction speaker, it is possible to compensate for frequency components that are not sensitive in the human hearing system. Curve 4 in the figure is a bone conduction speaker frequency response curve compensated accordingly for the hearing curve 3, with a resonance peak around the B-point frequency. The equal loudness curve 3 when the human ear receives the sound and the frequency response curve 4 generated by the bone conduction loudspeaker are combined, so that the sound heard by the human body is more ideal and the sound feeling is wider. As a specific example, the frequency of point A may be selected to be about 500Hz, and the frequency of point B may be selected to be about 2000 Hz. It should be noted that the above example of performing the corresponding frequency compensation on the bone conduction speaker should not be considered as the only feasible embodiment, and those skilled in the art can set an appropriate peak value and compensation mode according to the actual application scenario after understanding the principle.

It will be obvious to those having skill in the art that, after understanding the underlying principles involved, many modifications and variations in form and detail are possible in the implementation of the bone conduction speaker without departing from such principles, but such modifications and variations are within the scope of the above description. For example, the bone conduction hearing aid is also applicable to the above method for compensating the frequency response of the bone conduction speaker, that is, the frequency response characteristics of one or more corresponding hearing aids can be designed to compensate for the insensitivity to a specific frequency range that the bone conduction hearing aid may exhibit according to the hearing response curve of the hearing-impaired people, and in practical applications, the bone conduction hearing aid can be intelligently selected or the frequency response can be adjusted according to the input information of the user. For example, the system automatically obtains or the user inputs its own equal loudness curve and adjusts the frequency response of the bone conduction speaker according to the curve to compensate for the sound at a particular frequency. In one embodiment, for a point on the equal loudness curve with a low loudness (e.g., a minimum point on the curve), the frequency response amplitude of the bone conduction speaker near the frequency corresponding to the point can be increased, so as to obtain the desired sound quality. Similarly, for a point on the equal loudness curve where the loudness is high (e.g., a maximum point on the curve), the frequency response amplitude of the bone conduction speaker near the frequency corresponding to that point may be reduced. Further, there may be a plurality of maximum points or minimum points on the frequency response curve or the equal response curve of the human ear, and the corresponding compensation curve (frequency response curve) may also have a plurality of maximum values or minimum values. It will be apparent to those skilled in the art that the above description of the degree of human hearing sensitivity may be replaced by words of the same kind, such as "equal loudness curve", "hearing response curve", etc. In fact, the sensitivity of the human body to the hearing can also be regarded as a frequency response of sound, and in the description of the various embodiments of the present invention, the sound quality of the bone conduction speaker is finally shown by combining the sensitivity of the human body to the sound and the frequency response of the bone conduction speaker.

Under normal conditions, the sound quality of a bone conduction speaker is influenced by various factors such as the physical properties of each component of the speaker, the vibration transmission relationship among the components, the vibration transmission relationship between the speaker and the outside, and the efficiency of a vibration transmission system in transmitting vibration. The components of the bone conduction speaker itself include components that generate vibrations (such as, but not limited to, a transducer device), components that secure the speaker (such as, but not limited to, an earphone frame/earphone strap), and components that transmit vibrations (such as, but not limited to, a faceplate, a vibration transmission layer, etc.). The vibration transmission relationship between the components and the vibration transmission relationship between the loudspeaker and the outside are realized by the loudspeaker and the userThe contact pattern (e.g., without limitation, clamping force, contact area, contact shape, etc.) therebetween. As shown in fig. 11, an equivalent schematic diagram of a vibration generating and transmitting system of a bone conduction speaker includes an equivalent system of a bone conduction speaker including a fixed end 1101, a sensing terminal 1102, a vibration unit 1103, and a transducer unit 1104. Wherein the fixed end 1101 passes through the transmission relationship K1 (K in FIG. 4)₄) Coupled to vibration unit 1103, sensing terminal 1102 passes through transfer relationship K2 (R in FIG. 4)₃，k₃) Connected to the vibration unit 1103, the vibration unit 1103 passes through a transmission relationship K3 (R in fig. 4)₄，k₅) Is connected to the transducer assembly 1104.

The vibration unit referred to herein is a vibration body composed of a panel and a transducer device, and the transmission relationships K1, K2 and K3 are descriptions of the functional relationships between the respective parts in the equivalent system of the bone conduction speaker (which will be described in detail later). The vibration equation for an equivalent system can be expressed as:

m₃x″₃+R₃x′₃-R₄x′₄+(k₃+k₄)x₃+k₅(x₃-x₄)＝f₃ (8)

m₄x″₄+R₄x″₄-k₅(x₃-x₄)＝f₄ (9)

wherein m is₃Is the equivalent mass of the vibration unit 1103, m₄Is the equivalent mass, x, of the transducing device 1104₃Is the equivalent displacement, x, of the vibration unit 1103₄Is the equivalent displacement, k, of the transducing device 1104₃Is an equivalent elastic coefficient, k, between the sensing terminal 1102 and the vibration unit 1103₄Is an equivalent elastic coefficient, k, between the fixed end 1101 and the vibration unit 1103₅Is the equivalent elastic coefficient, R, between the transducer means 1104 and the vibration unit 1103₃Is the equivalent damping, R, between the sensing terminal 1102 and the vibration unit 1103₄Is the equivalent damping, f, between the transducer means 1104 and the vibration unit 1103₃And f₄Are respectively vibrationThe interaction force between the moving element 1103 and the transducer 1104. Equivalent amplitude A of vibration unit in system₃Comprises the following steps:

wherein f is₀Denotes unit driving force, and ω denotes vibration frequency. It can be seen that the factors affecting the frequency response of the bone conduction speaker include the vibration generating components (such as, but not limited to, the vibration unit, the transducer assembly, the housing, and the interconnection, as m in equation (10))₃，m₄，k₅，R₄Etc.), vibration transfer part (e.g., but not limited to, skin contact, properties of earphone rack/earphone strap, such as k in equation (10)₃，k₄，R₃Etc.). Varying the configuration of the parts of the bone-conduction speaker and the parameters of the connections between the components, e.g. varying the clamping force by an amount equivalent to varying k₄Changing the size of the glue is equivalent to changing R₄And k₅Changing the size of the relevant material, hardness, elasticity, damping, etc. is equivalent to changing k₃And R₃These may change the frequency response and sound quality of the bone conduction speaker.

In a specific embodiment, the fixing end 1101 may be a point or a region of the bone conduction speaker which is fixed relatively during the vibration process, and these points or regions may be regarded as the fixing end of the bone conduction speaker during the vibration process, and the fixing end may be composed of a specific component or a position determined according to the overall structure of the bone conduction speaker. For example, the bone conduction speaker can be suspended, adhered or adsorbed near the human ear by a specific device, and the structure and the shape of the bone conduction speaker can be designed to enable the bone conduction part to be attached to the skin of the human body.

The sensing terminal 1102 is a hearing system of a human body receiving a sound signal, and the vibration unit 1103 is a portion of the bone conduction speaker for protecting, supporting, and connecting the transducer device, and includes a portion in direct or indirect contact with a user, such as a vibration transmission layer or a panel for transmitting vibration to the user, and a housing for protecting and supporting other vibration generating elements, and the like. The transducing means 1104 is a generating means of acoustic vibrations and may be one or a combination of several of the transducing means discussed above.

A transmission relation K1, which connects the fixing end 1101 and the vibration unit 1103, represents a vibration transmission relation of the bone conduction speaker in operation between the vibration generating portion and the fixing end, and K1 depends on the shape and configuration of the bone conduction device. For example, the bone conduction speaker may be fixed on the head of a human body in a U-shaped earphone rack/earphone strap manner, or may be installed on a helmet, a fire mask, or other special-purpose mask, glasses, or other devices, and the shape and structure of the bone conduction speaker may affect the vibration transmission relationship K1, and further, the structure of the speaker may further include physical properties such as the composition material, quality, and the like of different parts of the bone conduction speaker. Transfer relationship K2 connects sensing terminal 402 and vibrating element 1103.

K2 depends on the composition of the delivery system including, but not limited to, the delivery of sound vibrations through the user's tissues to the hearing system. For example, when sound is transmitted to the hearing system through skin, subcutaneous tissue, bone, etc., the physical properties of various human tissues and the interconnection relationship have an effect on K2. Further, the vibration unit 1103 is in contact with the human tissue, and in different embodiments, the contact surface of the vibration unit may be a vibration transmission layer or a side surface of the panel, and the surface shape, size, interaction force with the human tissue, etc. of the contact surface may affect the transmission coefficient K2.

The transmission relationship K3 between the vibration unit 1103 and the transducer 1104 is determined by the connection properties inside the bone conduction speaker vibration generating device, and the connection between the transducer and the vibration unit through rigid or elastic means, or the relative position of the connecting member between the transducer and the vibration unit, changes the transmission efficiency of the transducer to transmit the vibration to the vibration unit, especially the panel, and affects the transmission relationship K3.

During the use of the bone conduction speaker, the sound generation and transmission process affect the final human perception of sound quality. Such as the above-mentioned fixed end, human sensory terminal, vibration unit, transducer device, and transfer relationships K1, K2, and K3, may have an effect on the sound effect quality of the bone conduction speaker. It should be noted that K1, K2, and K3 are only one representation of the connection modes of different device parts or systems involved in the vibration transmission process, and may include, but are not limited to, physical connection modes, force transmission modes, sound transmission efficiency, and the like.

The above description of a bone conduction speaker equivalent system is merely a specific example and should not be considered the only possible embodiment. It will be apparent to those skilled in the art having the benefit of this disclosure that numerous modifications and variations in form and detail can be made to the specific forms and steps of effecting the vibration transmission of a bone conduction speaker without departing from such principles, but such modifications and variations are within the scope of the above description. For example, the above-described K1, K2, and K3 may be simple vibration or mechanical transmission means, or may include a complex nonlinear transmission system, and the transmission relationship may be formed by directly connecting the respective parts, or may be transmitted in a non-contact manner.

In a specific embodiment, the bone conduction speaker is configured as shown in fig. 12, and includes an earphone rack/earphone strap 501, a vibration unit 1202, and a transduction device 1203. The vibration unit 1202 comprises a contact surface 1202a, a housing 1202b, and a transducer means 1203 is located inside and connected to the vibration unit 1202. Preferably, the vibration unit 502 is a panel including the above-described and vibration transmission layer, and the contact surface 1202a is a surface of the vibration unit 1202 contacting the user, preferably, an outer side surface of the vibration transmission layer.

During use, the earphone frame/earphone strap 1201 secures the bone conduction speaker at a particular location (e.g., the head) of the user, providing a clamping force between the vibration unit 1202 and the user. The contact surface 1202a is connected to the transducer 1203 and is in contact with the user, transmitting sound to the user through vibration. The fixed end 1101 shown in fig. 11 may be approximately selected to be a point where the position is relatively fixed when the bone conduction speaker is operated. If the bone conduction speaker is of a symmetrical structure, and if the driving forces provided by the transducer devices on both sides are equal in magnitude and opposite in direction in the working process, the central point on the earphone rack/earphone strap can be selected as an equivalent fixed end, for example, the position shown by 1204; if the bone conduction speaker is capable of providing stereo sound, i.e. the instant driving forces provided by the two transducing devices are different in magnitude, or the bone conduction speaker has asymmetry in structure, other points or areas on or beyond the earphone rack/earphone strap may be selected as the equivalent fixing ends. The fixed end referred to herein may be regarded as an equivalent end of the bone conduction speaker that is relatively fixed in position during generation of vibration. The fixed end 1101 and the vibration unit 1202 are connected by an earphone rack/earphone hanging belt 1201, and the transmission relationship K1 is related to the earphone rack/earphone hanging belt 1201 and the clamping force provided by the earphone rack/earphone hanging belt 1201, and depends on the physical property of the earphone rack/earphone hanging belt 1201. Preferably, the sound transmission efficiency of the bone conduction speaker can be changed by changing the clamping force provided by the earphone frame/earphone hanging belt, the quality of the earphone frame/earphone hanging belt and other physical quantities, and the frequency response of the system in a specific frequency range is influenced. For example, the earphone rack/earphone hanging belt made of a material with higher strength and the earphone rack/earphone hanging belt made of a material with lower strength can provide different clamping forces, or the structure of the earphone rack/earphone hanging belt is changed, and an auxiliary device capable of providing elastic force is added on the earphone rack/earphone hanging belt to change the clamping force, so that the transmission efficiency of sound is influenced; when the earphone rack/earphone hanging belt is worn, the size of the clamping force can be influenced by the size change of the earphone rack/earphone hanging belt, and the clamping force is increased along with the increase of the distance between the vibration units at the two ends of the earphone rack/earphone hanging belt.

In order to obtain the earphone rack/earphone hanging band satisfying the specific clamping force condition, a person skilled in the art can select materials with different rigidities and different moduli to make the earphone rack/earphone hanging band or adjust the size and the dimension of the earphone rack/earphone hanging band according to the actual situation. It should be noted that the clamping force of the earphone rack/earphone strap not only affects the sound transmission efficiency, but also affects the sound perception of the user in the bass frequency range. The clamping force referred to herein is a pressure between the contact surface and the user, preferably between 0.1N-5N, more preferably between 0.2N-4N, even more preferably between 0.2N-3N, even more preferably between 0.2N-1.5N, even more preferably between 0.3N-1.5N.

The material of the earphone frame/earphone hanging belt can determine the magnitude of the clamping force. Preferably, the material of the earphone rack/earphone hanging belt can be plastic with certain hardness. Such as but not limited to Acrylonitrile-butadiene-styrene copolymer (Acrylonitrile butadiene styrene), Polystyrene (PS), High Impact Polystyrene (HIPS), Polypropylene (PP), Polyethylene terephthalate (PET), Polyester (Polyester, PES), Polycarbonate (PC), Polyamide (PA), polyvinyl chloride (PVC), Polyurethane (PU), Polyvinylidene chloride (poly), Polyethylene (PE), Polymethyl methacrylate (PMMA), polyether (Polyetheretherketone, PEEK), phenol resin (phenol, PF), Urea formaldehyde resin (Urea-formaldehyde), Melamine-formaldehyde resin (UF), Melamine-formaldehyde resin (MF), and the like. More preferably, the material of the earphone frame/earphone hanging strap may include some metals, alloys (e.g., aluminum alloy, chrome molybdenum steel, scandium alloy, magnesium alloy, titanium alloy, magnesium-lithium alloy, nickel alloy, etc.), or composite materials. Further preferably, the material of the earphone rack/earphone hanging belt can be selected from materials with memory function. The memory material includes, but is not limited to, a memory alloy material, a polymer memory material, an inorganic non-memory material, etc. The memory alloy includes, but is not limited to, a titanium-nickel-copper memory alloy, a titanium-nickel-iron memory alloy, a titanium-nickel-chromium memory alloy, a copper-nickel memory alloy, a copper-aluminum memory alloy, a copper-zinc memory alloy, an iron memory alloy, etc. Polymeric memory materials include, but are not limited to, polynorbornene, trans-polyisoprene, styrene-butadiene copolymer, cross-linked polyethylene, polyurethane, polylactone, fluoropolymer, polyamide, cross-linked polyolefin, polyester, and the like. Inorganic non-memory materials include, but are not limited to, memory ceramics, memory glass, garnet, mica, and the like. It is further preferred that the memory material of the earphone rack/earphone sling has a memory temperature selected, preferably the memory temperature may be selected to be not lower than 10 ℃, more preferably the memory temperature is selected to be not lower than 40 ℃, further preferably the memory temperature is selected to be not lower than 60 ℃, still more preferably the memory temperature is selected to be not lower than 100 ℃. The proportion of the memory material in the earphone rack/earphone hanging strip material is not less than 5%, preferably not less than 7%, more preferably not less than 15%, further preferably not less than 30%, and still more preferably not less than 50%. The earphone rack/earphone hanging band referred to herein refers to a rear hanging structure that causes a bone conduction speaker to generate a clamping force. The memory material is located at different positions of the earphone rack/earphone hanging belt, and preferably, the memory material is located at a position where stress is concentrated on the earphone rack/earphone hanging belt, such as but not limited to a connection position of the earphone rack/earphone hanging belt and the vibration unit, a position near a symmetry center of the earphone rack/earphone hanging belt or a position where lines in the earphone rack/earphone hanging belt are densely distributed, and the like. In one embodiment, the memory alloy is used to make the earphone frame/earphone strap, and for different sizes of user's heads, the difference of the clamping force provided by the memory alloy is small, so that the wearing consistency is higher, and the tone quality consistency influenced by the clamping force is also higher. In another embodiment, the earphone rack/rear hanger made of memory alloy has good elasticity, can normally return to the original shape after being subjected to large deformation, and can still stably maintain the clamping force after being subjected to long-time deformation. In another embodiment, the earphone rack/earphone rear hanger made of memory alloy is light in weight and can provide deformation with a large degree of freedom, so that the earphone rack/earphone rear hanger can better fit a user.

The clamping force provides a pressure between the contact surface of the vibration generating portion of the bone conduction speaker and the user. Fig. 13-a and 13-B are vibration response curves of a bone conduction speaker under different pressures between the contact surface and the user in one embodiment. In the vibration transmission process, the clamping force is not beneficial to the transmission of medium-frequency and high-frequency vibration after being lower than a certain threshold value. As shown in (a), for the same vibration source (sound source), when the clamping force is 0.1N, the wearer receives vibration (sound) with a middle and high frequency portions significantly less than those received when the clamping force is 0.2N and 1.5N, i.e., at sound quality, when the clamping force is 0.1N, the middle and high frequency portions behave less than when the clamping force is 0.2N-1.5N. Meanwhile, in the present embodiment, the clamping force of 0.1N just ensures that the bone conduction earphone is worn on the user without falling off. Similarly, during vibration transmission, the clamping force is not beneficial to the transmission of low-frequency vibration after being larger than a certain threshold value. As shown in (b), for the same vibration source (sound source), when the clamping force is 5.0N, the wearer receives a vibration (sound) with a low frequency portion significantly less than the vibration (sound) received when the clamping force is 0.2N and 1.5N, i.e., in tone quality, when the clamping force is 5.0N, the low frequency portion behaves less than when the clamping force is 0.2N-1.5N. Also, in this embodiment, a 5.0N gripping force causes a noticeable pain sensation to the user.

In a specific embodiment, the pressure between the contact surface and the user is kept within a suitable range by selecting suitable earphone frame/earphone strap materials and setting suitable earphone frame/earphone strap results. The pressure between the contact surface and the user is above a certain threshold value, preferably 0.1N, more preferably 0.2N, even more preferably 0.3N, even more preferably 0.5N. The pressure between the contact surface and the user is less than another threshold value, preferably the threshold value is 5.0N, more preferably the threshold value is 4N, further preferably the threshold value is 3N, still further preferably the threshold value is 1.5N. After understanding the basic principle that the clamping force of the bone conduction speaker changes the frequency response of the bone conduction system, those skilled in the art can set a clamping force range satisfying different sound quality requirements through modification and replacement of the earphone rack/earphone strap material and structure, and the modification and replacement are still within the protection scope of the present specification.

The clamping force of the bone conduction speaker may be measured by a specific device or method. Fig. 14-a and 14-B are specific examples of measuring the clamping force of a bone conduction speaker. Points a and B are two points on the bone conduction speaker/earphone hanger/strap near the vibration unit in this embodiment. During the test, the point A or the point B is fixed, the other point is connected with a dynamometer, and the clamping force is measured when the distance L between the point A and the point B is between 125mm and 155 mm. Fig. 14-C is a frequency vibration response curve of a bone conduction speaker under different clamping force conditions, wherein the clamping force corresponding to the three curves is 0N, 0.61N and 1.05N, respectively. Fig. 14-C shows that as the clamping force of the bone conduction speaker increases, the load of the human face on the vibration unit (e.g., the faceplate, the vibration transmission layer connected to the faceplate, etc.) of the bone conduction speaker increases, and the vibration of the vibration plane is attenuated. Too little or too much clamping force may cause the bone conduction speaker to have a large frequency response during vibration (e.g., in the range of 500Hz-800Hz on the curves with clamping force of 0N and 1.05N). If the clamping force is too large (such as a corresponding curve when the clamping force is 1.05N), a wearer feels discomfort, and meanwhile, the vibration of the loudspeaker is weakened, and the sound becomes small; if the clamping force is too small (e.g. the corresponding curve when the clamping force is 0N), the wearer will feel more obvious vibration.

It should be noted that the above description of the method of varying the clamping force of a bone conduction speaker is merely a specific example and should not be considered as the only possible embodiment. It is obvious to a person skilled in the art, having the understanding of the basic principle of a bone conduction speaker, that changes may be made to the way the clamping force of the bone conduction speaker is changed for bone conduction speakers of different shapes and configurations without departing from this principle, but that such changes are still within the scope of the above description. For example, the bone conduction speaker frame may be made of a material having a memory function (e.g., memory metal), and the opening degree of the bone conduction speaker frame may be adjusted according to the head shape of a person. Further, an elastic bandage 1501 for adjusting the clamping force may be installed on the bone conduction speaker frame, as shown in fig. 15, and may provide an additional restoring force during the process of contracting or pulling the earphone rack/earphone strap away from the equilibrium position.

The transfer relationship K2 between the sensing terminal 1102 and the vibration unit 1103 also affects the frequency response of the bone conduction system. The sound heard by the human ear depends on the energy received by the cochlea, which is affected by different physical quantities during the transmission, and can be represented by the following formula:

P＝∫∫_Sα·f(a,R)·L·ds (11)

wherein, P is proportional to the energy received by the cochlea, S is the area of the contact surface 502a contacting the human face, α is a coefficient of dimensional transformation, f (a, R) represents the influence of the acceleration a of one point on the contact surface and the contact tightness R of the contact surface and the skin on the energy transfer, and L is the impedance of the mechanical wave transfer on any contact point, i.e. the transfer impedance of unit area.

As can be seen from (11), the transmission of sound is affected by the transmission impedance L, the vibration transmission efficiency of the bone conduction system is related to L, and the frequency response curve of the bone conduction system is a superposition of the frequency response curves of the points on the contact surface. Without loss of generality, in describing the bone conduction system interface structure, the term "interface" may refer to a surface that is at least partially in direct or indirect contact with the user, or may refer to a "contact layer" having a thickness that is at least partially in direct or indirect contact with the user. Factors influencing impedance change include the size, shape, roughness, stress size or stress distribution of the energy transfer area and the like. For example, the sound transmission effect is changed by changing the structure and the shape of the vibration unit 1202, thereby changing the sound quality of the bone conduction speaker. Merely by way of example, varying the respective physical characteristics of the contact surface 1202a of the vibration unit 1202 may achieve the effect of varying the transmission of sound.

A well-designed contact surface is provided with a gradient structure, which refers to areas of the contact surface where there is a change in height. The gradient structure may be a raised/recessed or stepped structure existing outside the contact surface (the side to be attached to the user), or may be a structure such as a projection/recess or a stepIs a convex/concave or step-like structure, etc. existing on the inner side (the side facing away from the user) of the contact surface. A vibration unit embodiment of a bone conduction speaker is shown in fig. 16-a, and a convex or concave (not shown in fig. 16-a) portion exists on a contact face 1601 (outside of the contact face). During the operation of the bone conduction speaker, the convex or concave part contacts with the skin of the human face, and the pressure of the contact face 1601 at different positions contacting with the human face is changed. The convex part is contacted with the human face more closely, and the skin and the subcutaneous tissue contacted with the convex part are subjected to larger pressure than other parts; accordingly, the skin and the subcutaneous tissue in contact with the depressed portions are subjected to less pressure than other portions. For example, three points a, B, and C exist on the contact face 1601 in fig. 16-a, respectively on the non-convex portion, the convex portion edge, and the convex portion of the contact face 1601. In the process of contacting with the skin, the clamping force F borne by the skin at the three points A, B and C_C>F_A>F_B. In some embodiments, the clamping force at point B is 0, i.e., point B is not in contact with the skin. Human skin and subcutaneous tissue exhibit different impedances and responses to sound at different pressures. The part with high pressure has small impedance rate and filter characteristic biased to high pass, and the part with low pressure has large impedance rate and filter characteristic biased to low pass. The impedance characteristics L of each part of the contact surface 1601 are different, and according to the formula (11), the response of different parts to the frequency when sound is transmitted is different, the effect of sound transmission through the full contact surface is equivalent to the sum of sound transmission of each part, and finally a smooth frequency response curve is formed when sound is transmitted to the brain, so that the occurrence of an excessively high resonance peak at low frequency or high frequency is avoided, and an ideal frequency response in the whole audio frequency bandwidth is obtained. Similarly, the material and thickness of the contact face 1601 may also affect the transmission of sound, thereby affecting the sound quality. For example, when the material of the contact surface is soft, the sound wave transmission effect in the low frequency range is better than that in the high frequency range, and when the material of the contact surface is hard, the sound wave transmission effect in the high frequency range is better than that in the low frequency range.

Fig. 16-B shows the frequency response of a bone conduction speaker with different interface. The dashed line corresponds to the frequency response of a bone conduction speaker with a raised structure on the contact surface, and the solid line corresponds to the frequency response of a bone conduction speaker without a raised structure on the contact surface. In the middle and low frequency range, the vibration of the non-convex structure is obviously weakened relative to the vibration of the convex structure, a 'deep pit' is formed on a frequency response curve and represents a less ideal frequency response, and therefore the sound quality of the bone conduction loudspeaker is influenced.

The above description of fig. 16-B is merely illustrative of specific examples, and it will be apparent to those skilled in the art that various modifications and changes can be made in the structure and components of the bone conduction speaker to obtain different frequency response effects, after understanding the basic principles affecting the frequency response of the bone conduction speaker.

It should be noted that the shape and structure of the contact face 1601 are not limited to the above description, and may be adapted to meet other specific requirements by those skilled in the art. For example, the convex or concave portions on the contact surface may be distributed at the edge of the contact surface or may be distributed at the middle of the contact surface. The contact surface may comprise one or more raised or recessed portions, and the raised and recessed portions may be distributed over the contact surface simultaneously. The material of the raised or recessed portions on the contact surface may be another material than the material of the contact surface, may be flexible, rigid, or a material more suitable for creating a particular pressure gradient; the material can be a memory material or a non-memory material; the material can be a single material or a composite material. The pattern of the convex or concave portion of the contact surface includes, but is not limited to, an axisymmetric pattern, a centrosymmetric pattern, a rotationally symmetric pattern, an asymmetric pattern, and the like. The pattern of the convex or concave part structure of the contact surface can be one pattern, and can also be a combination of two or more patterns. The contact surface includes, but is not limited to, having a certain smoothness, roughness, waviness, etc. The distribution of the positions of the convex or concave portions of the contact surface includes, but is not limited to, axisymmetric, centrosymmetric, rotationally symmetric, asymmetric distribution, and the like. The convex or concave parts of the contact surface can be at the edge of the contact surface or distributed in the contact surface.

1704-1709 in fig. 17 are specific embodiments of the contact surface structure described above.

Wherein 1704 is shown an example of the contact surface comprising a plurality of protrusions with similar shape and structure. The projections may be formed of the same or similar material as the rest of the panel or may be formed of a different material than the rest. In particular, the protrusions may be composed of a memory material and a vibration transfer layer material together, wherein the proportion of the memory material is not less than 10%, and preferably, the proportion of the memory material in the protrusions is not less than 50%. The area of the individual protrusions is 1% to 80% of the total area, preferably 5% to 70% of the total area, and more preferably 8% to 40% of the total area. The sum of the areas of all the projections is 5% to 80% of the total area, and preferably, the ratio is 10% to 60%. There may be at least 1 protrusion, preferably 1 protrusion, more preferably 2 protrusions, and even more preferably at least 5 protrusions. The shape of the bulge can be a circle, an ellipse, a triangle, a rectangle, a trapezoid, an irregular polygon or other similar figures, wherein the structure of the bulge can be symmetrical or asymmetrical, the position distribution of the bulge can also be symmetrical or asymmetrical, the number of the bulge can be one or more, the heights of the bulge can be the same or different, and the heights and the distribution of the bulge can form a certain gradient.

The structure 1705 shows an example of a combination of two or more patterns, in which the number of protrusions of different patterns may be one or more. The two or more convex shapes can be any two or more combinations of circles, ellipses, triangles, rectangles, trapezoids, irregular polygons or other similar figures. The material, number, area, symmetry, etc. of the protrusions are similar to those in graph 1704.

1706 is an example in which convex portions of the contact surface are distributed in the edge and inside of the contact surface, and the number of convex portions is not limited to that shown in the figure. The number of projections at the edge of the contact surface is 1% to 80% of the number of all projections, preferably the ratio is 5% to 70%, more preferably the ratio is 10% to 50%, and still more preferably the ratio is 30% to 40%. The material, number, area, shape, symmetry, etc. of the protrusions are similar to those in graph 1704.

In the figure 1707, a pattern of a concave portion of the contact surface is shown, where the structure of the concave portion may be symmetrical or asymmetrical, the distribution of the positions of the concave portions may also be symmetrical or asymmetrical, the number of the concave portions may be one or more, the shapes of the concave portions may be the same or different, and the concave portions may be hollowed out. The area of the individual depressions is 1% to 80% of the total area, preferably 5% to 70% of the total area, more preferably 8% to 40% of the total area. The total area of all depressions is 5% to 80% of the total area, preferably the ratio is 10% to 60%. There may be at least 1 recess, preferably 1 recess, more preferably 2 recesses, even more preferably at least 5 recesses. The concave shape may be circular, oval, triangular, rectangular, trapezoidal, irregular polygonal, or other similar shapes.

In the drawing 1708 is an example in which the contact surface has both convex portions and concave portions, and the number of convex and concave portions is not limited to one or more. The ratio of the number of concavities to the number of convexities is 0.1 to 100, preferably, the ratio is 1 to 80, more preferably, the ratio is 5 to 60, and further preferably, the ratio is 10 to 20. The material, area, shape, symmetry, etc. of the individual protrusions/recessions are similar to those in graph 1704.

1709 is an example of a contact surface with a certain waviness. The corrugation is formed by arranging more than two protrusions/depressions or a combination of two protrusions/depressions, preferably, the distances between adjacent protrusions/depressions are equal, and more preferably, the distances between protrusions/depressions are arranged in an equal difference.

1710 is an example of a protrusion with a larger area on the contact surface. The area of the protrusion accounts for 30-80% of the total area of the contact surface. Preferably, a part of the edge of the projection and a part of the edge of the contact surface are substantially in contact with each other.

In this figure 1711 there is shown a contact surface having a first protrusion of larger area and a second protrusion of smaller area on the first protrusion. The larger area of the protrusions represents 30-80% of the total area of the contact surface and the smaller area of the protrusions represents 1-30% of the total area of the contact surface, preferably the ratio is 5-20%. The smaller area accounts for 5% -80% of the larger area, preferably the ratio is 10% -30%.

The above description of the bone conduction speaker interface structure is merely a specific example and should not be considered the only possible embodiment. It will be apparent to those skilled in the art having the benefit of the teachings presented herein that the basic principles underlying the bone conduction speaker interface structure which affect the sound quality of a bone conduction speaker may be modified and varied in form and detail without departing from such principles, but that such modifications and variations are within the scope of the foregoing description. For example, the number of protrusions or depressions is not limited to that shown in FIG. 17, and modifications may be made to the protrusion, depression, or contact surface pattern described above to some extent while remaining within the scope of the protection described above. Moreover, the same or different shapes and materials can be used for the contact surfaces of at least one or more vibration units contained in the bone conduction speaker, and the vibration effect transmitted on different contact surfaces can also be different along with the difference of the properties of the contact surfaces, and finally different sound quality effects are obtained.

As can be seen from fig. 11, the vibration mode of the transducer 1104 in the bone conduction speaker vibration system and the mode K3 connected to the vibration unit 1103 also have an effect on the sound effect of the system. Preferably, the transducing device comprises a vibrating plate, a vibration transmitting plate, a set of coils and a magnetic circuit system, and more preferably, the transducing device comprises a composite vibrating device consisting of a plurality of vibrating plates and vibration transmitting plates. The frequency response of the system generated sound is influenced by the physical properties of the vibrating plate and the vibration transmission plate, and the sound effect meeting the actual requirement can be generated by selecting the size, the shape, the material, the thickness, the vibration transmission mode and the like of the specific vibrating plate and the vibration transmission plate.

An embodiment of a compound vibration device is shown in fig. 18-a and 18-B, comprising: the vibration plate 1801 is a composite vibration member composed of a vibration plate 1802 and a vibration plate 1801, wherein the vibration plate 1801 is provided as a first annular body 1813, three first supporting rods 1814 which converge towards the center are arranged in the first annular body, and the convergence center position of the three first supporting rods 1814 is fixed with the center of the vibration plate 1802. The center of the vibrating plate 1802 is a notch 1820 matching the convergence center and the first strut. The vibrating plate 1802 is provided with a second circular ring 1821 having a radius different from that of the vibrating plate 1801, and three second struts 1822 having a thickness different from that of the first struts 1814, wherein the first struts 1814 and the second struts 1822 are arranged in a staggered manner during assembly, which may be, but is not limited to, at an angle of 60 degrees.

The first supporting rod and the second supporting rod can be straight rods or be arranged into other shapes meeting specific requirements, the number of the supporting rods can be more than two, and the supporting rods are symmetrically or asymmetrically arranged to meet the requirements of economy, practical effect and the like. The vibration transfer plate 1801 has a thin thickness and can increase elastic force, and the vibration transfer plate 1801 is caught at the center of the groove 1820 of the vibration plate 1802. A voice coil 1808 is attached to the lower side of the second annular body 1821 of the diaphragm 1802. The compound vibration device further includes a bottom plate 1812, on which bottom plate 1812 is disposed an annular magnet 1810, inside which annular magnet 1810 is concentrically disposed an inner magnet 1811; an inner magnetic conducting plate 1809 is arranged on the top surface of the inner magnet 1811, an annular magnetic conducting plate 1807 is arranged on the annular magnet 1810, a gasket 1806 is fixedly arranged above the annular magnetic conducting plate 1807, and a first annular body 1813 of the vibration transmission piece 1801 is fixedly connected with the gasket 1806. The whole compound vibration device is connected to the outside through a panel 1830, and the panel 1830 is fixedly connected to the convergence center position of the vibration plate 1801 and is fixed to the center positions of the vibration plate 1802 and the vibration plate 1801 by engagement.

By using the composite vibration device composed of the vibration plate and the vibration transmission plate, the frequency response as shown in fig. 19 is obtained, two resonance peaks are generated by the double composite vibration, the resonance peaks are moved by adjusting the parameters of the size, the material and the like of the two components, the resonance peak of the low frequency is moved to the lower frequency, the resonance peak of the high frequency is moved to the higher frequency, and preferably, the stiffness coefficient of the vibration plate is larger than that of the vibration transmission plate. The frequency response curve shown in fig. 19 can be finally fitted to a dotted line, that is, a flat frequency response in an ideal state, and the range of these resonance peaks may be set within the frequency range of the sound audible to the human ear or not, and preferably, both resonance peaks are not within the frequency range of the sound audible to the human ear; more preferably, one of the formants is within a frequency range of a sound audible to a human ear and the other one of the formants is outside the frequency range of the sound audible to the human ear; more preferably, both resonance peaks are in the frequency range of the sound audible to the human ear; and still further preferably, both resonance peaks are in the frequency range of sounds audible to the human ear and their peak frequencies are between 80Hz-18000 Hz; still further preferably, both resonance peaks are in the frequency range of sounds audible to the human ear and have a peak value between 200Hz-15000 Hz; even more preferably, both resonance peaks are in the frequency range of sound available to the human ear and have a peak value between 500Hz-12000 Hz; still further preferably, both resonance peaks are in the frequency range of sound available to the human ear and have a peak value between 800Hz-11000 Hz. The peaks of the resonance peaks preferably have a difference in frequency, e.g., the peaks of the two resonance peaks differ by at least 500 Hz; preferably, the peaks of the two resonance peaks differ by at least 1000 Hz; even more preferably, the peaks of the two resonance peaks differ by at least 2000 Hz; still further preferably, the peaks of the two resonance peaks differ by at least 5000 Hz. For better results, both resonance peaks may be within the audible range of the human ear and the peak frequencies of the resonance peaks differ by at least 500 Hz; preferably, both resonance peaks may be within the audible range of the human ear, the peaks of the two resonance peaks differing by at least 1000 Hz; still further preferably, both resonance peaks may be within the audible range of human ears, the peaks of the two resonance peaks differing by at least 2000 Hz; and still further preferably, both resonance peaks may be within the audible range of human ears, the peaks of the two resonance peaks differing by at least 3000 Hz; still further preferably, both resonance peaks may be within the audible range of human ears, the peaks of the two resonance peaks differing by at least 4000 Hz. One of the two resonance peaks may be within the human audible range and the other outside the human audible range, and the peak frequencies of the two resonance peaks differ by at least 500 Hz; preferably, one resonance peak is within the human audible range and the other is outside the human audible range, and the peak frequencies of the two resonance peaks differ by at least 1000 Hz; more preferably, one resonance peak is within the human audible range and the other is outside the human audible range, and the peak frequencies of the two resonance peaks differ by at least 2000 Hz; further preferably, one resonance peak is within the human audible range and the other is outside the human audible range, and the peak frequencies of the two resonance peaks differ by at least 3000 Hz; still further preferably, one resonance peak is within the human audible range and the other is outside the human audible range, and the peak frequencies of the two resonance peaks differ by at least 4000 Hz. Both resonance peaks may be between frequencies 5Hz-30000Hz, and the peak frequencies of the two resonance peaks differ by at least 400 Hz; preferably, both resonance peaks may be between frequencies 5Hz-30000Hz, and the peak frequencies of the two resonance peaks differ by at least 1000 Hz; more preferably, both resonance peaks may be between frequencies 5Hz-30000Hz, and the peak frequencies of the two resonance peaks differ by at least 2000 Hz; further preferably, both resonance peaks may be between frequencies 5Hz-30000Hz, and the peak frequencies of the two resonance peaks differ by at least 3000 Hz; still further preferably, both resonance peaks may be at a frequency between 5Hz-30000Hz, and the peak frequencies of the two resonance peaks differ by at least 4000 Hz. Both resonance peaks may be at a frequency between 20Hz and 20000Hz and the peak frequencies of the two resonance peaks differ by at least 400 Hz; preferably, both resonance peaks may be at a frequency between 20Hz and 20000Hz and the peak frequencies of the two resonance peaks differ by at least 1000 Hz; more preferably, both resonance peaks may be between the frequencies 20Hz-20000Hz, and the peak frequencies of the two resonance peaks differ by at least 2000 Hz; further preferably, both resonance peaks may be between the frequencies 20Hz-20000Hz and the peak frequencies of the two resonance peaks differ by at least 3000 Hz; even further preferably, both resonance peaks may be at a frequency between 20Hz-20000Hz and the peak frequencies of the two resonance peaks differ by at least 4000 Hz. Both resonance peaks may be between frequencies 100Hz-18000Hz, and the peak frequencies of the two resonance peaks differ by at least 400 Hz; preferably, both resonance peaks may be between frequencies 100Hz-18000Hz, and the peak frequencies of the two resonance peaks differ by at least 1000 Hz; more preferably, both resonance peaks may be between frequencies 100Hz-18000Hz, and the peak frequencies of the two resonance peaks differ by at least 2000 Hz; further preferably, both resonance peaks may be between frequencies 100Hz-18000Hz, and the peak frequencies of the two resonance peaks differ by at least 3000 Hz; still further preferably, both resonance peaks may be between frequencies 100Hz-18000Hz, and the peak frequencies of the two resonance peaks differ by at least 4000 Hz. Both resonance peaks may be between frequencies 200Hz-12000Hz, and the peak frequencies of the two resonance peaks differ by at least 400 Hz; preferably, both resonance peaks may be between frequencies 200Hz-12000Hz, and the peak frequencies of the two resonance peaks differ by at least 1000 Hz; more preferably, both resonance peaks may be between frequencies 200Hz-12000Hz, and the peak frequencies of the two resonance peaks differ by at least 2000 Hz; further preferably, both resonance peaks may be between frequencies 200Hz-12000Hz, and the peak frequencies of the two resonance peaks differ by at least 3000 Hz; even more preferably, both resonance peaks may be between frequencies 200Hz-12000Hz, and the peak frequencies of the two resonance peaks differ by at least 4000 Hz. Both resonance peaks may be between 500Hz and 10000Hz in frequency and the peak frequencies of the two resonance peaks differ by at least 400 Hz; preferably, both resonance peaks may be between 500Hz-10000Hz in frequency and the peak frequencies of the two resonance peaks differ by at least 1000 Hz; more preferably, both resonance peaks may be between 500Hz and 10000Hz in frequency and the peak frequencies of the two resonance peaks differ by at least 2000 Hz; further preferably, both resonance peaks may be between 500Hz and 10000Hz in frequency and the peak frequencies of the two resonance peaks differ by at least 3000 Hz; even more preferably, both resonance peaks may be at a frequency between 500Hz and 10000Hz, and the peak frequencies of the two resonance peaks differ by at least 4000 Hz. Thus, the resonance response range of the loudspeaker is widened, and the sound quality meeting the conditions is obtained. It should be noted that, in the actual use process, a plurality of vibration transmitting plates and vibration plates may be arranged to form a multi-layer vibration structure, which respectively corresponds to different frequency response ranges, so as to realize full-range full-frequency-response high-quality speaker vibration, or to make the frequency response curve meet the use requirements in some specific frequency ranges. For example, in bone conduction hearing aids, one or more transducers consisting of vibrating and vibrating plates with a resonance frequency in the range of 100Hz to 10000Hz may be selected in order to meet normal hearing requirements. A description of a composite vibration device composed of a vibration plate and a vibration transmission plate is presented in a patent application entitled "a bone conduction speaker and a composite vibration device thereof" disclosed in chinese patent application No. 201110438083.9 filed on 23.12.2011, which is incorporated herein by reference in its entirety.

As shown in fig. 20, in another embodiment, the vibration system includes a vibration plate 2002, a first vibration plate 2003 and a second vibration plate 2001, the first vibration plate 2003 fixes the vibration plate 2002 and the second vibration plate 2001 to a housing 2019, and a composite vibration system composed of the vibration plate 2002, the first vibration plate 2003 and the second vibration plate 2001 can generate not less than two resonance peaks to generate a flatter frequency response curve in the audible range of the hearing system, thereby improving the sound quality of the bone conduction speaker. The vibration system equivalent model is shown in fig. 21-a:

the vibration damper comprises a shell 2101, a panel 2102, a voice coil 2103, a magnetic circuit 2104, a first vibration transmission piece 2105, a second vibration transmission piece 2106 and a vibration plate 2107, wherein the first vibration transmission piece, the second vibration transmission piece and the vibration plate are abstracted to form elements containing elasticity and damping, and the shell, the panel, the voice coil and the magnetic circuit can be abstracted to form equivalent mass blocks. The vibration equation for the system can be expressed as:

m₆x″₆+R₆(x₆-x₅)′+k₆(x₆-x₅)＝F (12)

m₇x″₇+R₇(x₇-x₅)′+k₇(x₇-x₅)＝-F (13)

m₅x″₅-R₆(x₆-x₅)′-R₇(x₇-x₅)′+R₈x′₅+k₈x₅-k₆(x₆-x₅)-k₇(x₇-x₅)＝0 (14)

wherein F is the driving force, k₆Is the equivalent stiffness coefficient, k, of the second vibration-transmitting plate₇Is the equivalent stiffness coefficient, k, of the diaphragm₈Is the equivalent stiffness coefficient, R, of the first vibration-transmitting plate₆Is equivalent damping of the second vibration-transmitting plate, R₇For equivalent damping of the vibrating plate, R₈Is the equivalent damping of the first vibration-transfer plate, m₅Is the mass of the panel, m₆Mass m of the magnetic circuit system₇Is the voice coil mass, x₅Is the panel displacement, x₆For magnetic circuit system displacement, x₇Is the voice coil displacement. The amplitude of the panel 2102 can be found to be:

where ω denotes the angular frequency of the vibration, f₀Indicating a unit driving force.

The vibration system of the bone conduction speaker transmits vibration to a user through a panel, and as can be seen from equation (15), the vibration efficiency of the system is related to the stiffness coefficient and vibration damping of the vibration plate, the first vibration transmission plate and the second vibration transmission plate, and preferably, the stiffness coefficient k of the vibration plate₇Greater than the second vibration coefficient k₆Coefficient of stiffness k of diaphragm₇Greater than the first vibration coefficient k₈. The number of resonance peaks generated by the triple composite vibration system with the first vibration transmission plate is more than that generated by the composite vibration system without the first vibration transmission plate, and preferably, at least three resonance peaks are generated; more preferably, at least one of the resonance peaks is not within the audible range of the human ear; more preferably, the resonance peaks are all within the audible range of the human ear; still further preferably, the resonance peaks are all within the audible range of the human ear and have peak frequencies no higher than 18000 Hz; still further preferably, the harmonic peaks are all in the frequency range of sounds audible to the human ear and have peak values between 100Hz-15000 Hz; still further preferably, the resonant peaks are all in the frequency range of sound available to the human ear and have peaks in the range of 200Hz-12000Hz; still further preferably, the harmonic peaks are all in the frequency range of sound available to the human ear and have peak values between 500Hz-11000 Hz. The peaks of the resonance peaks preferably have a difference in frequency, e.g., there are at least two resonance peaks that differ by at least 200 Hz; preferably, the peaks at which there are at least two resonance peaks differ by at least 500 Hz; more preferably, the peaks where there are at least two resonance peaks differ by at least 1000 Hz; still further preferably, the peaks at which there are at least two resonance peaks differ by at least 2000 Hz; still further preferably, the peaks where there are at least two resonance peaks differ by at least 5000 Hz. For better results, the resonance peaks may all be within the audible range of human ears, and the peak frequencies of at least two resonance peaks differ by at least 500 Hz; preferably, the resonance peaks may all be within the audible range of human ears, with peaks of at least two resonance peaks differing by at least 1000 Hz; more preferably, the harmonic peaks may all be within the audible range of human ears, with at least two harmonic peaks differing by at least 1000 Hz; still further preferably, the resonance peaks may all be within the audible range of human ears, with peaks of at least two resonance peaks differing by at least 2000 Hz; and still further preferably, the harmonic peaks may all be within the audible range of human ears, with at least two harmonic peaks differing by at least 3000 Hz; still further preferably, the resonance peaks may all be within the audible range of human ears, with at least two resonance peaks present with a peak to peak difference of at least 4000 Hz. Two of the resonance peaks may be within the human audible range, the other one is outside the human audible range, and the peak frequencies at which at least two resonance peaks are present differ by at least 500 Hz; preferably, two resonance peaks are within the human audible range, the other resonance peak is outside the human audible range, and the peak frequencies at which at least two resonance peaks are present differ by at least 1000 Hz; more preferably, the two resonance peaks are within the human audible range and the other is outside the human audible range, and the peak frequencies at which at least two resonance peaks are present differ by at least 2000 Hz; further preferably, the two resonance peaks are within the human audible range, the other is outside the human audible range, and the peak frequencies at which at least two resonance peaks are present differ by at least 3000 Hz; even more preferably, twoOne of the resonance peaks is within the human audible range and the other is outside the human audible range, and the peak frequencies at which at least two resonance peaks are present differ by at least 4000 Hz. One of the resonance peaks may be within the human audible range, the other two may be outside the human audible range, and the peak frequencies at which at least two resonance peaks are present differ by at least 500 Hz; preferably, one resonance peak is within the human audible range, the other two resonance peaks are outside the human audible range, and the peak frequencies of at least two resonance peaks differ by at least 1000 Hz; more preferably, one resonance peak is within the human audible range, the other two are outside the human audible range, and the peak frequencies at which at least two resonance peaks are present differ by at least 2000 Hz; further preferably, one resonance peak is within the human audible range, the other two are outside the human audible range, and the peak frequencies of at least two resonance peaks differ by at least 3000 Hz; still further preferably, one of the resonance peaks is within the human audible range, the other two are outside the human audible range, and the peak frequencies at which at least two of the resonance peaks are present differ by at least 4000 Hz. The resonance peaks may all be between frequencies 5Hz-30000Hz, and the peak frequencies at which there are at least two resonance peaks differ by at least 400 Hz; preferably, the resonance peaks may all be between frequencies 5Hz-30000Hz, and the peak frequencies at which at least two resonance peaks are present differ by at least 1000 Hz; more preferably, the resonance peaks may all be between frequencies 5Hz-30000Hz, and the peak frequencies at which at least two resonance peaks are present differ by at least 2000 Hz; further preferably, the resonance peaks may all be between frequencies 5Hz-30000Hz, and the peak frequencies at which at least two resonance peaks are present differ by at least 3000 Hz; even more preferably, the resonance peaks may all be between frequencies 5Hz-30000Hz, and the peak frequencies at which at least two resonance peaks are present differ by at least 4000 Hz. The resonance peaks may both be at a frequency between 20Hz and 20000Hz and the peak frequencies at which at least two resonance peaks are present differ by at least 400 Hz; preferably, the resonance peaks may both be between the frequencies 20Hz-20000Hz, and the peak frequencies at which at least two resonance peaks are present differ by at least 1000 Hz; more preferably, the resonance peaks may both be between the frequencies 20Hz-20000Hz, and the peak frequencies at which at least two resonance peaks are present differ by at least 2000 Hz;further preferably, the resonance peaks may both be between the frequencies 20Hz-20000Hz and the peak frequencies of at least two resonance peaks differ by at least 3000 Hz; even more preferably, the resonance peaks may both be at a frequency between 20Hz and 20000Hz, and the peak frequencies at which at least two resonance peaks are present differ by at least 4000 Hz. The resonance peaks may all be between frequencies 100Hz-18000Hz, and the peak frequencies at which there are at least two resonance peaks differ by at least 400 Hz; preferably, the resonance peaks may all be between frequencies 100Hz-18000Hz, and the peak frequencies at which there are at least two resonance peaks differ by at least 1000 Hz; more preferably, the resonance peaks may all be between frequencies 100Hz-18000Hz, and the peak frequencies at which there are at least two resonance peaks differ by at least 2000 Hz; further preferably, the resonance peaks may all be between frequencies 100Hz-18000Hz, and the peak frequencies at which at least two resonance peaks are present differ by at least 3000 Hz; still further preferably, the resonance peaks may all be between frequencies 100Hz-18000Hz, and the peak frequencies at which at least two resonance peaks are present differ by at least 4000 Hz. The resonance peaks may all be between frequencies 200Hz-12000Hz, and the peak frequencies at which at least two resonance peaks are present differ by at least 400 Hz; preferably, the resonance peaks may all be between frequencies 200Hz-12000Hz, and the peak frequencies at which at least two resonance peaks are present differ by at least 1000 Hz; more preferably, the resonance peaks may all be between frequencies 200Hz-12000Hz, and the peak frequencies at which at least two resonance peaks are present differ by at least 2000 Hz; further preferably, the resonance peaks may all be between frequencies 200Hz-12000Hz, and the peak frequencies at which at least two resonance peaks are present differ by at least 3000 Hz; even more preferably, the resonance peaks may all be between frequencies 200Hz-12000Hz, and the peak frequencies at which at least two resonance peaks are present differ by at least 4000 Hz. The resonance peaks may all be between 500Hz and 10000Hz, and the peak frequencies at which there are at least two resonance peaks differ by at least 400 Hz; preferably, the resonance peaks may all be between 500Hz and 10000Hz, and the peak frequencies at which there are at least two resonance peaks differ by at least 1000 Hz; more preferably, the resonance peaks may all be between 500Hz-10000Hz in frequency, and the peak frequencies of at least two resonance peaks differ by at least 2000 Hz; further preferably, the resonance peaks may all be at a frequency between 500Hz and 10000HzAnd the peak frequencies of at least two resonance peaks differ by at least 3000 Hz; even more preferably, the resonance peaks may all be between 500Hz and 10000Hz, and the peak frequencies of at least two resonance peaks differ by at least 4000 Hz. To further achieve a better effect, the at least two resonance peaks may be within the audible range of human ears and the resonance peak produced by the first vibration plate is not higher than 20000Hz, preferably the at least two resonance peaks may be within the audible range of human ears and the resonance peak produced by the first vibration plate is not higher than 10000Hz, preferably the at least two resonance peaks may be within the audible range of human ears and the resonance peak produced by the first vibration plate is not higher than 5000Hz, preferably the at least two resonance peaks may be within the audible range of human ears and the resonance peak produced by the first vibration plate is not higher than 2000Hz, preferably the at least two resonance peaks may be within the audible range of human ears and the resonance peak produced by the first vibration plate is not higher than 1000Hz, preferably the at least two resonance peaks may be within the audible range of human ears and the resonance peak produced by the first vibration plate is not higher than 500Hz, preferably, the at least two resonance peaks may be within the human audible range and the resonance peak produced by the first vibration plate is no higher than 300Hz, preferably, the at least two resonance peaks may be within the human audible range and the resonance peak produced by the first vibration plate is no higher than 200 Hz; preferably, the at least two resonance peaks may be within an audible range of human ears, and the resonance peak produced by the first vibration plate is in a range of 20-20000Hz, preferably, the at least two resonance peaks may be within the audible range of human ears, and the resonance peak produced by the first vibration plate is in a range of 20-10000Hz, preferably, the at least two resonance peaks may be within the audible range of human ears, and the resonance peak produced by the first vibration plate is in a range of 20-5000Hz, preferably, the at least two resonance peaks may be within the audible range of human ears, and the resonance peak produced by the first vibration plate is in a range of 20-2000Hz, preferably, the at least two resonance peaks may be within the audible range of human ears, and the resonance peak produced by the first vibration plate is in a range of 20-1000Hz, preferably, the at least two resonance peaks may be within the audible range of human ears, and a resonance peak generated by the first vibration plateIn the range of 20-500Hz, preferably, at least two resonance peaks may be in the audible range of human ears, and the resonance peak generated by the first vibration plate is in the range of 20-300Hz, preferably, at least two resonance peaks may be in the audible range of human ears, and the resonance peak generated by the first vibration plate is in the range of 20-200 Hz; more preferably, the transduction apparatus generates at least two resonance peaks in the human audible range and the resonance peak generated by the first vibration plate is not higher than 20000Hz, more preferably, the transduction apparatus generates at least two resonance peaks in the human audible range and the resonance peak generated by the first vibration plate is not higher than 10000Hz, more preferably, the transduction apparatus generates at least two resonance peaks in the human audible range and the resonance peak generated by the first vibration plate is not higher than 5000Hz, more preferably, the transduction apparatus generates at least two resonance peaks in the human audible range and the resonance peak generated by the first vibration plate is not higher than 2000Hz, more preferably, the transduction apparatus generates at least two resonance peaks in the human audible range and the resonance peak generated by the first vibration plate is not higher than 1000Hz, more preferably, the transduction apparatus generates at least two resonance peaks in the human audible range and the resonance peak generated by the first vibration plate is not higher than 500Hz, more preferably, the transduction apparatus generates at least two resonance peaks in the human audible range and the resonance peak generated by the first vibration plate is not higher than 300Hz, and more preferably, the transduction apparatus generates at least two resonance peaks in the human audible range and the resonance peak generated by the first vibration plate is not higher than 200 Hz; more preferably, the transduction means produces at least two resonance peaks in the audible range of human ears and the resonance peak produced by the first vibration plate is in the range of 20-20000Hz, more preferably, the transduction means produces at least two resonance peaks in the audible range of human ears and the resonance peak produced by the first vibration plate is in the range of 20-10000Hz, more preferably, the transduction means produces at least two resonance peaks in the audible range of human ears and the resonance peak produced by the first vibration plate is in the range of 20-5000Hz, more preferably, the transduction means produces at least two resonance peaks in the audible range of human ears and the resonance peak produced by the first vibration plate is in the range of 20-2000Hz, more preferably, the transduction means produces at least two resonance peaks in the audible range of human ears and the resonance peak produced by the first vibration plate is in the audible range of 20-2000HzThe patch produces a resonance peak in the range of 20-1000Hz, more preferably the transducing means produces at least two resonance peaks in the human audible range and the resonance peak produced by the first patch is in the range of 20-500Hz, more preferably the transducing means produces at least two resonance peaks in the human audible range and the resonance peak produced by the first patch is in the range of 20-300Hz, more preferably the transducing means produces at least two resonance peaks in the human audible range and the resonance peak produced by the first patch is in the range of 20-200 Hz. In one embodiment, the frequency response shown in fig. 21-B can be obtained by using a triple composite vibration system composed of a vibration plate, a first vibration transmission plate and a second vibration transmission plate, and the triple composite vibration system having the first vibration transmission plate generates three distinct resonance peaks, resulting in a flatter frequency response and improved sound quality.

By changing the parameters such as the size, the material and the like of the first vibration transmission piece, the resonance peak can be moved, and finally, the frequency response under an ideal state is obtained. For example, the stiffness coefficient of the first vibration plate is reduced to a design value, so that the resonance peak can be moved to a design position towards low frequency, the sensitivity of the frequency response of the bone conduction loudspeaker in a low frequency range can be greatly improved, and better sound quality can be easily obtained. As shown in fig. 21-C, when the stiffness coefficient of the first vibration plate gradually decreases (i.e. the first vibration plate changes from hard to soft), the resonance peak moves toward the low frequency direction, and the sensitivity of the frequency response of the bone conduction speaker in the low frequency range is significantly improved. Preferably, the first vibration-transmitting plate is an elastic plate. The elasticity is determined by the material, thickness, structure and the like of the first vibration-transmitting plate. The material of the first vibration-transmitting plate, such as, but not limited to, steel (e.g., but not limited to, stainless steel, carbon steel, etc.), light alloy (e.g., but not limited to, aluminum alloy, beryllium copper, magnesium alloy, titanium alloy, etc.), plastic (e.g., but not limited to, high molecular weight polyethylene, blow-molded nylon, engineering plastic, etc.), or other single or composite materials that can achieve the same performance. For composite materials, such as but not limited to reinforcing materials such as glass fibers, carbon fibers, boron fibers, graphite fibers, graphene fibers, silicon carbide fibers or aramid fibers, composites of other organic and/or inorganic materials can also be used, such as various types of glass fiber reinforced plastics composed of glass fiber reinforced unsaturated polyester, epoxy resin or phenolic resin matrix. The first vibration-transmitting sheet has a thickness of not less than 0.005mm, preferably, a thickness of 0.005mm to 3mm, more preferably, a thickness of 0.01mm to 2mm, still more preferably, a thickness of 0.01mm to 1mm, and further preferably, a thickness of 0.02mm to 0.5 mm. The first vibration-transmitting plate may be configured to be annular, preferably, to include at least one circular ring, preferably, to include at least two circular rings, which may be concentric circular rings or non-concentric circular rings, the circular rings being connected to each other by at least two struts, the struts radiating from the outer ring to the center of the inner ring, further preferably, to include at least one elliptical ring, further preferably, to include at least two elliptical rings, different elliptical rings having different radii of curvature, the circular rings being connected to each other by struts, and further preferably, the first vibration-transmitting plate includes at least one square ring. The first vibration plate structure can also be set to be a plate shape, preferably, a hollow pattern is arranged on the first vibration plate structure, and the area of the hollow pattern is not less than the area without hollowing. The materials, the thicknesses and the structures in the above description can be combined into different vibration transmission sheets. For example, the ring-shaped vibration-transmitting plates have different thickness distributions, preferably the strut thickness is equal to the ring thickness, further preferably the strut thickness is greater than the ring thickness, and further preferably the inner ring thickness is greater than the outer ring thickness.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

Example one

A bone conduction speaker, comprising: the earphone comprises a U-shaped earphone frame/earphone hanging belt, two sound vibration units and an energy conversion device fixedly connected in the sound vibration units. The vibration unit comprises a contact surface and a shell, wherein the contact surface is the outer side of the silica gel transmission layer. A gradient structure is present on the contact surface, said gradient structure comprising a raised structure. The contact surface provided by the earphone rack/earphone hanging strap is in contact with the skin with a clamping force, which is unevenly distributed over the contact surface. The gradient structure portion has different sound transmission efficiency from the non-gradient structure portion.

Example two

The difference between the present embodiment and the first embodiment is: the earphone rack/earphone hanging belt comprises an alloy with a memory function, can be matched with head curves of different users, has good elasticity and has better wearing comfort. After the earphone frame/earphone hanging belt is deformed for a certain time, the original shape can still be recovered. The certain time herein may be ten minutes, thirty minutes, one hour, two hours, five hours, or may be one day, two days, ten days, one month, one year or more. The clamping force provided by the earphone rack/earphone hanging belt keeps stable, and the situation that the clamping force gradually decreases after the earphone rack/earphone hanging belt is lengthened along with the wearing time is avoided. The pressure of the bone conduction speaker in contact with the surface of the human body is within a certain proper range, so that the human body cannot feel excessive pressure to generate pain or obvious vibration when wearing the bone conduction speaker. In the using process, the clamping force of the bone conduction loudspeaker is in the range of 0.2N-1.5N.

EXAMPLE III

The present embodiment is different from the first embodiment or the second embodiment in that: the elastic coefficient of the earphone rack/earphone strap is kept within a certain range, so that the value of the frequency response curve of the bone conduction speaker in the vicinity of low frequency (e.g., below 500 Hz) is higher than that in the vicinity of high frequency (e.g., above 4000 Hz) during use.

Example four

The difference between the present embodiment and the first embodiment is: the bone conduction speaker is integrated on the spectacle frame or inside the special-purpose helmet and mask.

EXAMPLE five

The difference between the present embodiment and the first embodiment is: the vibration unit of the bone conduction speaker comprises two or more panels, and different panels or vibration transmission layers connected with the panels have different gradient structures on the contact surface with a user. For example, one of the contact surfaces is provided with a convex structure, and the other contact surface is provided with a groove mechanism; or the gradient structures on the two contact surfaces are both convex or concave structures, but at least one of the shapes and the number of the convex structures is different.

EXAMPLE six

A portable bone conduction hearing aid can choose to adopt various frequency response curves, and a user or a tester can select an appropriate hearing aid response curve to compensate according to the actual response curve of a hearing system. In addition, the vibrating device in the bone conduction hearing aid enables the hearing aid to generate a relatively ideal frequency response in a specific frequency range, for example, the frequency range is 500Hz to 4000Hz according to actual needs.

EXAMPLE seven

A vibration generating portion of a bone conduction speaker is shown in fig. 22-a. The transducer includes a magnetic circuit system composed of a magnetic conductive plate 2210, a magnet 2211 and a magnetic conductive body 2212, a vibrating plate 2214, a coil 2215, a first vibrating plate 2216 and a second vibrating plate 2217. The panel 2213 protrudes from the housing 2219 and is glued to the vibrating plate 2214 by glue, and the first vibrating plate 2216 is used to attach the transducer assembly to the housing 2219 to form a suspension.

During the operation of the bone conduction speaker, the triple vibration system consisting of the vibration plate 2214, the first vibration plate 2216 and the second vibration plate 2217 can generate a flatter frequency response curve, thereby improving the sound quality of the bone conduction speaker. The first vibration plate 2216 elastically connects the transducer to the housing 2219, so that the vibration transmitted from the transducer to the housing can be reduced, thereby effectively reducing the sound leakage caused by the vibration of the housing and reducing the influence of the vibration of the housing on the tone quality of the bone conduction speaker. Fig. 22-B shows response curves of the vibration intensity of the vibration generating section casing and the vibration intensity of the panel with frequency. Among them, a thick line shows a frequency response of a vibration generating portion after using the first vibration plate 2216, and a thin line shows a frequency response of a vibration generating portion after not using the first vibration plate 2216. It can be seen that the device without the first vibration plate 2216 vibrates more than the device with the first vibration plate 2216 in the frequency range of 500Hz or more. Fig. 22-C shows a comparison of leakage sound in the case where the first vibration conduction sheet 2216 is used and the case where the first vibration conduction sheet 2216 is not used in the vibration generating portion. Wherein the leakage sound in the mid-frequency range (e.g., about 1000 Hz) of a device using the first vibration plate 2216 is less than the leakage sound in the corresponding frequency range of a device not using the first vibration plate 2216. Therefore, the first vibration transmission sheet is used between the panel and the shell to effectively reduce the vibration of the shell, thereby reducing the sound leakage.

The first vibrating plate can be made of materials such as, but not limited to, stainless steel, beryllium copper, plastic, polycarbonate, and the like, and the thickness of the first vibrating plate is in the range of 0.01mm-1 mm.

Example eight

The present embodiment is different from the seventh embodiment in that: as shown in fig. 23, a vibration transmission layer 2320 (for example, but not limited to, silicone) is added on the face plate 2313, and the vibration transmission layer 2320 can deform to adapt to the shape of the skin. The portion of the vibration transfer layer 2320 that is in contact with the panel 2313 is higher than the portion of the vibration transfer layer 2320 that is not in contact with the panel 2313, forming a stepped structure. One or more small holes 2321 are designed at a portion of the vibration transmission layer 2320 not in contact with the face plate 2313 (a portion of the vibration transmission layer 2320 not projected in fig. 23). The small holes are designed in the vibration transmission layer to reduce the sound leakage: the connection between the panel 2313 and the housing 2319 through the vibration transmission layer 2320 becomes weak, and the vibration transmitted from the panel 2313 to the housing 2319 through the vibration transmission layer 2320 is reduced, so that the sound leakage caused by the vibration of the housing 2319 is reduced; the area of the rear surface of the part, which is not projected, of the vibration transmission layer 2320, which is provided with the small holes 2321 is reduced, so that air which can be driven is reduced, and sound leakage caused by air vibration is reduced; after the small hole 2321 is formed in the part, not protruding, of the vibration transmission layer 2320, sound waves in the shell formed by air vibration in the shell are guided out of the shell and offset with sound leakage sound waves formed by air vibration induced by the shell 2319, and sound leakage is reduced.

Example nine

The present embodiment is different from the seventh embodiment in that: because the panel protrudes out of the loudspeaker shell, and the panel and the loudspeaker shell are connected by the first vibration conduction sheet, the coupling degree of the panel and the shell is greatly reduced, and the first vibration conduction sheet can provide certain deformation, so that the panel has higher freedom degree in fitting with a user, can better adapt to a complex fitting surface (shown in a right drawing in fig. 24-A), and can enable the panel to incline at a certain angle relative to the shell. Preferably, the inclination angle is not more than 5 °.

Further, the vibration efficiency of the speaker varies depending on the attachment state. The good bonding state has higher vibration transmission efficiency. As shown in fig. 24-B, the thick lines indicate the vibration transmission efficiency in the state of good bonding, and the thin lines indicate the vibration transmission efficiency in the state of poor bonding, and it can be seen that the vibration transmission efficiency is higher in the state of good bonding.

Example ten

The present embodiment is different from embodiment seven in that: the surrounding edge is added to the edge of the shell, and in the process that the shell is in contact with the skin, the surrounding edge enables the acting force to be distributed more uniformly, so that the wearing comfort of the bone conduction speaker is improved. As shown in fig. 25, surroundThere is a height difference d between the edge 2510 and the face plate 2513₀. The force of the skin on the face plate 2513 causes the distance d between the face plate 2513 and the surrounding edge 2510 to decrease, which is when the pressure between the bone conduction speaker and the user is greater than the first vibration plate 2516, which deforms to d₀During the power that the time receives, unnecessary clamp force can transmit skin via surrounding edge 2510, and does not exert an influence to the clamp force of vibration part for the uniformity of clamp force is higher, thereby guarantees tone quality.

EXAMPLE eleven

The shape of the panel is shown in fig. 26, and the connection 2620 between the panel 2610 and the transducer device (not shown in fig. 26) is shown in phantom. The transducer device transmits vibration to the panel 2610 through the connection component 2620, and the connection component 2620 is located at the center of vibration of the panel 2610. The center O of the connecting member 2620 is spaced L from both sides of the panel 2610₁And L₂. By changing the size of the panel 2610, the position of the connection member 2620 on the panel 2610 can change the attachment performance of the panel to the skin and the transmission efficiency of vibration. Preferably, L₁And L₂Is set to be greater than 1, more preferably, L₁And L₂Is set to be greater than 1.61, further preferably, L₁And L₂The ratio of (d) is set to be greater than 2. For another example, a large panel, a medium panel, and a small panel may be selected for use in the vibrating device. The large panel herein refers to the panel described in fig. 26, the area of the panel 2610 is larger than the area of the connection member 2620, the medium panel refers to the panel 2610 having the same size as the connection member 2620, and the small panel refers to the panel 2610 having a smaller area than the connection member 2620. The different sizes of panels and the different positions of the connection component 2620 have different distributions of the transmitted vibration on the attachment surface of the wearer, which may further bring the difference of the volume and the tone quality.

Example twelve

The embodiment relates to various configurations of gradient structures outside the contact surface of the vibration unit of the bone conduction loudspeaker. As shown in fig. 27, the gradient structure has a different number of protrusions, and the protrusions are located at different positions outside the contact surface. In the scheme 1, a bulge is arranged at the position close to the edge of the contact surface; in the scheme 2, a bulge is arranged at the center of the contact surface; in the scheme 3, two bulges are arranged on the contact surface and are respectively close to the edge positions of the contact surface; there are three protrusions in case 4; there are four protrusions in case 5. The number and position of the protrusions have different influences on the vibration transmission efficiency of the contact surface. As shown in fig. 28-a and 28-B, the frequency response curve exhibited by the contact surface without the convex structure is different from that exhibited by the contact surface with the convex structure in the case of the schemes 1 to 5. It can be seen that after the gradient structure (protrusion) is added on the binding surface, the frequency response curve is obviously raised within the range of 300Hz-1100Hz, which shows that the middle and low frequency part of the sound is obviously improved after the gradient structure is added.

EXAMPLE thirteen

The embodiment relates to various configurations of a gradient structure inside a vibration contact surface of a bone conduction loudspeaker. As shown in fig. 29, the gradient structure of the contact surface is located on the inner side of the contact surface, i.e. the side facing away from the user. In the scheme A, the inner side of the vibration transmission layer is attached to the panel, and a certain inclination angle exists between the attaching surface and the outer side of the vibration transmission layer; in the scheme B, a step structure is arranged on the inner side of the vibration transmission layer, and the step is positioned at the edge of the vibration transmission layer; in the scheme C, the other step structure is arranged on the inner side of the vibration transmission layer and is positioned in the center of the vibration transmission layer; in the scheme D, a plurality of step structures exist on the inner side of the vibration transmission layer. Because there is the gradient structure in the contact surface inboard for the position of the different points on the binding face of contact surface and panel has different vibration transmission efficiency, can widen the frequency response curve of vibration, makes frequency response "flat" more in certain frequency range, thereby improves bone conduction speaker's tone quality.

Example fourteen

The present embodiment is different from embodiment eight in that: as shown in fig. 30, sound introducing holes are formed in both the vibration transmission layer 3020 and the casing 3019, and sound waves in the casing due to air vibration in the casing are guided out of the casing through the sound introducing holes and cancel sound waves of leakage sound due to air vibration induced by the casing 3019, thereby reducing the leakage sound.

The above-mentioned embodiments only express some specific embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, variations and modifications can be made without departing from the spirit of the present invention, such as the several ways of changing the bone conduction sound transmission disclosed in the present specification, and any combination and modification can be made, but these modifications and combinations are still within the scope of the present invention as defined in the appended claims.

Claims

1. A method for improving the sound quality of a bone conduction earphone,

providing a bone conduction headset comprising a vibration unit, a headset frame/headset strap connected to the vibration unit,

the vibration unit at least comprises a contact surface which is in direct or indirect contact with a user;

causing the pressure between the contact face of the vibration unit and the user to be greater than a third threshold, which is a minimum force that enables the speaker contact face to maintain contact with the user;

so that the pressure between the contact surface of the vibration unit and the user is less than a fourth threshold value, which is the minimum force with which the contact surface of the loudspeaker makes the user feel pain.

2. The method of claim 1, wherein the pressure between the contact surface of the vibratory unit and the user is greater than a first threshold, the first threshold being greater than the third threshold, the first threshold improving the efficiency of the transmission of the mid and high frequency signals while improving the sound quality of the mid and high frequency signals.

3. The method of claim 1, wherein the pressure between the contact surface of the vibration unit and the user is less than a second threshold, the second threshold being less than the fourth threshold, the second threshold improving the transmission efficiency of the low frequency signals and improving the sound quality of the low frequency signals.

4. The method according to claim 1, characterized in that the third threshold value corresponds to a pressure of 0.1N: the pressure corresponding to the fourth threshold value is 5N.

5. The method according to claim 2 or 3, wherein the first threshold is 0.2N; the second threshold is 1.5N.

6. A bone conduction earphone is characterized in that the bone conduction earphone comprises a vibration unit and an earphone frame/earphone hanging belt, wherein the vibration unit at least comprises a contact surface which is in direct or indirect contact with a user;

7. The bone conduction headset of claim 6, wherein the headset frame/headset strap of the speaker comprises a memory alloy or an engineering plastic material.

8. The bone conduction headset of claim 6, wherein the pressure between the contact surface of the vibration unit and the user is greater than a first threshold, the first threshold being greater than the third threshold, the first threshold corresponding to improved mid and high frequency transmission efficiency while also improving mid and high frequency sound quality.

9. Bone conduction earphone according to claim 6, characterized in that the pressure between the contact surface of the vibration unit and the user is brought to be lower than a second threshold value, which is lower than the fourth threshold value, which second threshold value corresponds to an increased efficiency of the low frequency transmission while at the same time improving the low frequency sound quality.

10. The bone conduction headset of claim 6, wherein the third threshold corresponds to a pressure of 0.1N: the pressure corresponding to the fourth threshold value is 5N.

11. Bone conduction headset according to claim 8, 9, characterized in that the first threshold value is 0.2N; the second threshold is 1.5N.