WO2019082330A1

WO2019082330A1 - Earphone microphone

Info

Publication number: WO2019082330A1
Application number: PCT/JP2017/038673
Authority: WO
Inventors: 康仁原
Original assignee: 康仁原
Priority date: 2017-10-26
Filing date: 2017-10-26
Publication date: 2019-05-02

Abstract

[Problem] To provide a microphone for an earphone, for which reduction in device size is realized, energy loss is reduced, and signal conversion efficiency is improved as a result of suppression of scattering transmission of transmission-side sound pressure generated inside the ear canal. [Solution] This earphone microphone functions as both: a microphone that is used by being worn on one ear and detects sound transmitted from the outer ear canal as a speech signal; and an earphone that outputs a received-speech signal as sound. The earphone microphone comprises: a vibration plate that is disposed so as to face the inside of the outer ear canal and that vibrates in response to receiving a vibration inside the outer ear canal; a core member that is disposed so as to face the vibration plate and is formed of a rod-shaped magnetic body; and a magnet part that is disposed adjacent to the core member and generates a magnetic field in the region surrounding the core member. The microphone has a first coil that is wound around the core member and detects changes in the magnetic field caused by vibration of the vibration plate generated by sound transmitted from the outer ear canal as a speech signal. The earphone has a second coil that is wound around the core member and outputs sound generated by the vibration plate being vibrated as a result of changes in the magnetic field caused by an input received-speech signal.

Description

Earphone microphone

The present invention relates to an earphone microphone that listens to voice and music, and transmits and receives voice.

2. Description of the Related Art Conventionally, a microphone-equipped earphone that performs transmission and reception using an earphone that is attached to one of the ears and a microphone that is provided at an intermediate portion of a cable is used for a transmission / reception device such as a mobile phone. . The user can use the microphone and the earphone to transmit and receive without having a mobile phone, but the microphone picks up ambient sounds other than the transmission voice, so it can not be used in places with large external noise There's a problem.

In order to solve this problem, conventionally, a handset has been proposed in which an earphone is inserted into one ear and a bone conduction microphone is inserted into the other ear (see, for example, Patent Document 1). However, in the invention described in Patent Document 1, since the bone conduction microphone is inserted into the other ear, it is not possible to listen to music with both ears after the call is completed. On the other hand, an earphone microphone capable of full duplex voice communication has been developed by inserting a speaker and a microphone in one of the ear canals. In this type of earphone microphone, the reception side voice of the other party of communication is transmitted from the speaker to the human body as the vibration of the eardrum through the ear canal, and at the same time the voice emitted by the human body on the transmitter vibrates the eardrum through the ear canal The microphone is introduced into the ear canal and acquired as a transmission signal by the microphone disposed in the ear canal, and the voice is converted into an electric signal, and in the ear canal, the reception signal and the transmission signal are mixed, Means are provided for removing incoming signals that are mixed in with the signal.
JP-A-8-181754

As means for removing the reception signal mixed in the conventional transmission signal described above, for example, there is a system for separating transmission and reception using an electric circuit such as 2-wire to 4-wire conversion and residual reception voice signal removal processing by DSP or the like. is there. However, in this method, the remaining received voice becomes several 10 to 100 times as large as that of the transmission signal due to energy loss in the bridge circuit of 2-wire to 4-wire conversion, so that the deterioration of transmission voice quality becomes a problem. In addition, if the speaker and the microphone are separately arranged in the ear canal to enable transmission and reception, the speaker and the microphone are difficult to miniaturize because the speaker and the microphone are arranged in the ear canal, and the speaker and the microphone are arranged in the ear canal As a result, there is a problem that the transmission sound signal transmitted to the microphone is attenuated as a result of the sound pressure of the transmission sound transmitted from the tympanic membrane being dispersed and transmitted.

Therefore, the problem to be solved by the present invention is to reduce the energy loss while reducing the size of the device in the microphone earphone, and to suppress the transmission conduction of the sound pressure on the transmitting side generated in the ear canal, thereby making the signal An object of the present invention is to provide an apparatus capable of improving conversion efficiency.

In order to solve the above-mentioned problems, the present invention is an earphone microphone which is attached to be inserted into the ear canal and which serves both as a microphone for detecting a sound transmitted from the ear canal as a speech signal and an earphone for outputting a reception signal as sound. A diaphragm which is disposed inward of the ear canal and which is vibrated by receiving vibration in the ear canal, a core member which is disposed facing the diaphragm and is formed of a rod-like magnetic material, and a core member The first coil includes: a magnet portion adjacent to the core member for generating a magnetic field; the microphone is wound around the core member and detects as a speech signal a change in the magnetic field due to the vibration of the diaphragm due to the sound transmitted from the ear canal And the earphone is wound around the core member and vibrates the diaphragm to output sound by the change of the magnetic field due to the input reception signal. And having a coil.

In the above invention, the first coil and the second coil can be wound around the core member separately or partially or entirely overlapping each other. When the first coil and the second coil are separately wound and wound, the numbers of turns may be the same, or may be different from each other, and some or all of the coils may be overlapped. In the case of winding around the core member, the two electric wires forming the respective coils may be spirally twisted to be overlapped and wound around the core member as a single stranded wire.

According to the present invention, the first coil and the second coil wound around the same core member detect the change of the magnetic field due to the vibration of the diaphragm due to the sound transmitted from the ear canal, and the change of the magnetic field due to the reception signal Since the diaphragm is vibrated to output sound, the device can be miniaturized and energy loss can be reduced, and the sound pressure on the transmitting side generated in the ear canal can be suppressed from being dispersed and conducted, thereby improving the signal conversion efficiency. Can be improved.

It is an explanatory view showing the appearance of the earphone microphone concerning an embodiment of the present invention. It is a sectional view showing the internal configuration of the earphone microphone concerning an embodiment. It is a block diagram showing the circuit composition of the earphone microphone concerning an embodiment. It is a block diagram showing the circuit composition of the earphone microphone concerning a modification.

(Configuration of earphone microphone)
Hereinafter, embodiments of the present invention will be described. FIG. 1 shows the appearance of the earphone microphone according to the embodiment of the present invention, and FIG. 2 shows the internal configuration of the earphone microphone. Further, FIG. 3 shows a circuit configuration of the earphone microphone. The same or equivalent parts or components are denoted by the same or equivalent reference numerals throughout the drawings. The embodiment described below is an example of an apparatus for embodying the technical idea of the present invention, and the technical idea of the present invention includes the material, shape, structure, and the like of each component. The arrangement etc. are not specified to the following. Various changes can be added to the technical idea of the present invention within the scope of the claims.

As shown in FIG. 1, the input / output terminal 29 of the earphone microphone 10 is connected to, for example, a smartphone 1 having a music reproduction function and a hands-free call function. The smartphone 1 incorporates a microphone and a speaker, and when the earphone microphone 10 is not used, the smartphone 1 is used as a telephone set for making calls by itself. The earphone microphone 10 is connected to the input / output terminal 29 of the earphone microphone 10 via a signal line in the flexible connection cable 35.

As shown in FIG. 2, the earphone microphone 10 is inserted into the external auditory canal from the outside on the auricle side, and an ear hole insertion portion 43 having a through hole 42 communicating with the ear canal formed at the center and a proximal end of the ear hole insertion portion 43 And a main body case 45 in which a space 44 communicating with the through hole 42 is formed. In the space portion 44, a diaphragm 46 and

electromagnetic conversion coils

411 and 412 capable of mutually converting mechanical vibration and an electrical signal of the diaphragm 46 are provided.

In addition, a resin-made ear pad 48 closely attached to the inner surface of the ear canal is attached to the outer periphery of the tip of the ear canal insertion portion 43, and a signal in the connection cable 35 conductively connected to the electromagnetic conversion coil 47 is attached to the body case 45. A protective cover 49 is provided for drawing out and protecting the tip of the wire to the outside. The earphone microphone 10 combines the functions of a microphone and an earphone by a single sound transducer 40 consisting of a diaphragm 46 and

electromagnetic conversion coils

411 and 412.

With regard to the function of the electromagnetic conversion coil 411 as a microphone, sound transmitted by air propagation in the ear canal is transmitted from the inner ear side into the space portion 44 through the through hole 42. The diaphragm 46 catches and vibrates the sound vibration (air vibration) propagated in the space portion 44. The electromagnetic conversion coil 411 captures mechanical vibration of the diaphragm 46, converts it into an electric signal, and outputs the electric signal from the connection cable 35.

Regarding the function of the electromagnetic conversion coil 412 as an earphone, an audio signal input from a signal line in the connection cable 35 vibrates the diaphragm 46 via the electromagnetic conversion coil 47 to generate air vibration in the space portion 44. . This air vibration is sent out as sound from the space 44 through the through hole 42 to the inner ear side of the ear canal.

In the following, a full duplex communication circuit using one audio transducer 40 consisting of

electromagnetic conversion coils

411 and 412 will be described. FIG. 3 shows the circuit of the earphone microphone. As shown in FIG. 3, a full duplex communication circuit using an audio transducer 40 having a reception and transmission function, and an analog signal processing circuit, a digital signal processing circuit, and circuits capable of full duplex communication are provided. It consists of a set of algorithms.

The analog signal processing circuit includes a full duplex speech circuit using the audio transducer 40, and the digital signal processing circuit uses an echo of the transfer function identification filter that simulates transfer characteristics including transfer characteristics of the analog signal processing circuit. (Leakage of the reception signal to the transmission signal via the sound transducer 40) is canceled. Therefore, the digital signal processing circuit preferably further comprises a series of algorithms (coefficient update algorithm, system identification correction strength calculation algorithm, false correction detection and simultaneous call detection algorithm, transfer function identification filter learning algorithm), using these transfer functions The coefficients of the identification filter are preferably determined by the convergence results of the iterative operation.

The sound transducer 40 is a mechanism for being used as both a microphone that is inserted into the ear canal and detects sound transmitted from the ear canal as a speech signal and an earphone that outputs a reception signal as sound. Specifically, the audio transducer 40 is disposed inward of the ear canal, and is formed of a rod-like magnetic material disposed so as to face the diaphragm 46 and the diaphragm 46 that is vibrated by receiving vibration in the ear canal. A core member 472, a magnet unit 471 adjacent to the core member 472 and generating a magnetic field around the core member 472, and a dual coil wound around the core member 472.

The mechanism for causing the microphone of the audio transducer 40 to function includes one of the above-described dual coils, and more specifically, the magnetic field due to the vibration of the diaphragm 46 by the sound transmitted from the ear canal wound around the core member 472 It has a first electromagnetic conversion coil 411 that detects a change as a speech signal. Further, as a mechanism for causing the earphone of the sound transducer 40 to function, the other coil of the dual coil described above is included, and wound around the core member 472 and the diaphragm 46 is vibrated by the change of the magnetic field by the input reception signal. A second electromagnetic transducer coil 412 for outputting sound is included. In the present embodiment, the first and second

electromagnetic conversion coils

411 and 412 are respectively separated and wound around the core member 472 and magnetic lines of force generated by the respective coils are separated to some extent. As described above, since the first and second

electromagnetic conversion coils

411 and 412 are separated and wound around the core member 472, the number of turns of each coil should be the same or be set separately so as to be different from each other. You can also.

Then, on the earphone side, the outputs from the electromagnetic conversion coil 411 are both input to the output amplifier 422 and converted to digital signals by the A / D converter 431, and the digital transmission output through the echo canceller 440. It is output as the signal D1. On the other hand, on the microphone side, the digital input signal D2 is input to the D / A converter 432 via the echo canceller 440, converted into an analog signal, amplified by the output amplifier 422, and then input to the electromagnetic conversion coil 412. . The echo canceller 440 is a function to suppress and remove an acoustic echo generated between the microphone and the earphone. For example, the transmission characteristic between the earphone and the microphone is acquired, and the acquired transmission characteristic is transmitted from the other party. To the voice signal to extract the signal reproduced from the earphone and reached the microphone. For a transfer system whose transfer characteristics are not known, system identification by adaptive control is performed in which a known signal is input and the characteristic of the transfer system is estimated from an output signal to the input signal. An adaptive filter is used for this system identification, and this adaptive filter can usually be configured by an FIR filter.

(Modification example)
The description of the embodiment described above is an example of the present invention. Therefore, the present invention is not limited to the above-described embodiment, and various changes can be made according to the design and the like without departing from the technical concept of the present invention. For example, in the embodiment described above, the first and second electromagnetic conversion coils 411 and 412 forming the dual coil are separated and wound around the core member 472 respectively, but as shown in FIG. May be overlapped and wound. For this purpose, for example, two electric wires constituting each of the first and second electromagnetic conversion coils 411 and 412 are spirally twisted into one stranded wire, and the twisted wire is wound around the core member 472. You may In this case, the first and second electromagnetic conversion coils 411 and 412 can be completely overlapped and easily wound around the core member 472.
Thus, by partially or wholly overlapping and winding the first and second electromagnetic conversion coils 411 and 412, some or all of the magnetic field lines generated by the respective coils are overlapped, which is inexpensive The device can be miniaturized at a manufacturing cost.

(Action effect)
According to the earphone microphone of the present embodiment having the above configuration, the change of the magnetic field due to the vibration of the diaphragm due to the sound transmitted from the ear canal by the first coil and the second coil wound around the same core member Since the diaphragm is vibrated by the change of the magnetic field caused by the reception signal to output the sound while detecting, while reducing the size of the device while reducing the energy loss, the sound pressure on the transmitting side generated in the ear canal It is possible to improve the signal conversion efficiency by suppressing dispersion conduction.

D1: Digital transmission signal D2: Digital input signal 1: Smartphone 10: Earphone microphone 35: Connection cable 40: Audio transducer 42: Through hole 43: Ear hole insertion portion 44: Space portion 45: Body case 46: Diaphragm 47: Electromagnetic conversion coil 48: Ear pad 49: Protective cover 411: Electromagnetic conversion coil (first electromagnetic coil)
412: Electromagnetic conversion coil (second electromagnetic coil)
421 ... input amplifier 422 ... output amplifier 431 ... A / D converter 432 ... D / A converter 440 ... echo canceller 471 ... magnet section 472 ... core member

Claims

An earphone microphone that is inserted into the ear canal and used as a microphone for detecting as a speech signal a sound transmitted from the ear canal and an earphone that outputs a reception signal as a sound,
A diaphragm which is disposed inward of the ear canal and is vibrated by vibration in the ear canal;
A core member disposed facing the diaphragm and formed of a rod-like magnetic material;
And a magnet unit adjacent to the core member to generate a magnetic field around the core member,
The microphone includes a first coil which is wound around the core member and detects, as the speech signal, a change in the magnetic field due to the vibration of the diaphragm caused by the sound transmitted from the ear canal.
The earphone microphone includes a second coil which is wound around the core member and which vibrates the diaphragm to output sound by a change in the magnetic field according to the input reception signal.
The earphone microphone according to claim 1, wherein the first coil and the second coil are separately wound around the core member.
The earphone microphone according to claim 2, wherein the first coil and the second coil have the same number of turns.
The earphone microphone according to claim 2, wherein the first coil and the second coil have different numbers of turns.
The earphone microphone according to claim 1, wherein the first coil and the second coil are wound around the core member such that a part or all of the first coil and the second coil overlap.
The first coil and the second coil are characterized in that two electric wires forming the respective coils are twisted in a spiral shape and wound around the core member as a single stranded wire. The earphone microphone according to claim 5.