JPH0125015Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a bone conduction microphone that is installed in a handset together with a headphone.

Conventionally, hands-free voice-controlled transceivers have been used for conversations between multiple people at distant locations in construction sites, workplaces, group activities at schools, etc., and foreign language learning devices have been used to communicate with parents. A handset with a headphone and a microphone attached to the headband is used for conversation between a specific learner and the teacher through the handset and slave device.

However, in the case of the above handset, all external noises present in the external environment are input into the microphone along with the voice emitted from the mouth, and as a result, the side receiving this voice input can only hear the mixed noise. You will be able to hear sounds that are difficult to hear.

For this reason, there has been a problem that, for example, at work sites where industrial machinery, civil engineering machinery, etc. are in operation, the above-mentioned handsets cannot function satisfactorily for business-related conversations.

Further, in the voice control type transceiver, the above-mentioned noise causes problems such as erroneous control of switching between transmitting and receiving, and making it impossible to make a telephone call. In other words, in the handset/receiver, there has been a problem in that the voice-to-noise ratio on the transmitting side is reduced, making it impossible to receive calls.

On the other hand, in response to this, ear plug-type bone conduction microphones that are inserted into the external ear canal have been provided.

The bone conduction microphone transmits bone vibrations to a piezoelectric element through an encapsulating body having an inserter that receives sound vibrations in the external auditory canal, and a polarization voltage is generated from the piezoelectric element via a lead wire in response to the generation of strain caused by this vibration. obtained,
This voltage is reproduced as audio through an amplifier, etc.
After making necessary sound quality corrections, the sound can be output to earphones or headphones for listening.

Therefore, external noise is not input to this bone conduction microphone along with the audio signal.
Only clear audio can be heard.

However, when an earplug-type bone conduction microphone like the one above is assembled into a handset together with a headphone like the one above, the headphone and bone conduction microphone end up blocking the left and right ear holes, respectively. When used for such purposes, external sounds and other on-site work noises will not directly enter the ears, which is extremely dangerous.

Therefore, with the present invention, the ear is placed in contact with the temporal region behind the ear (the part called the temporal mastoid process or the lower border of the temporal bone...the same applies hereinafter) without blocking the ear, which prevents the ear from being bothered by external sounds and noise. To provide a bone conduction type microphone for use in a handset, etc., capable of converting only clear voice into sound without causing noise, and furthermore, to provide a bone conduction type microphone which is configured to have excellent characteristics in terms of sound conversion efficiency.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a handset equipped with a bone conduction microphone according to the present invention. Reference numeral 1 denotes a headband made of an elastic member, and holding members 2, 2a made of synthetic resin or the like are attached to both ends of the headband 1.
A sliding adjustment rod 4, which is integrated with the headphone 3, is inserted into one of the holding members 2 with contact resistance and held therein, and the other holding member 2a has a tip end as shown in FIG. The upper ends of the sliding adjustment rods 5, which are bifurcated 5a and 5b, are inserted and held with a certain contact resistance.

Attachment holes 7a,
Elastic protrusions 6a, 8a formed on the back surface of the bone conduction microphone 6 and the backing plate 8 are press-fitted into these mounting holes 7a, 7b, and can be freely replaced. That is,
The bone conduction microphone 6 and the patch plate 8 are
When the headband 1 is hung on the head and the headphone 3 is brought into contact with one ear so as to cover it, it is attached so as to come into contact with the temporal region behind the other ear and the temporal region in front of the other ear, respectively.

Next, the bone conduction microphone 6 will be explained. This bone conduction microphone 6 includes a synthetic resin housing 11 having a U-shaped cross section, and a housing 11 provided in the housing 11 near the opening of the housing 11.
A flexible diaphragm 12 whose periphery is fixed on the inner circumferential surface, and a piezoelectric element that is attached to the inner surface of the flexible diaphragm 12 and causes distortion in the crystal when subjected to the vibration of the flexible diaphragm 12. 13, and a lead wire 14 which is polarized by the distortion of the piezoelectric element 13 and takes out the polarized voltage generated between the diaphragm 12 and the piezoelectric element 13 to the outside via an impedance conversion element such as a resistor or semiconductor. , an acoustic vibration transmission plate 15 having one end attached to the outer surface of the flexible diaphragm 12 , a shield cap 16 as a shielding material made of a magnetically conductive metal plate covering the outer surface of the casing 11 , and It consists of an elastic coating 17 made of soft rubber or soft synthetic resin that is coated on the outer surface of the shield cap 16.

The housing 11 has a substantially cylindrical shape, and the piezoelectric element 13 and the like are housed therein. However, in order to avoid electrical and magnetic induction interference from the outside, the housing 11 may be made of resin if necessary. By making it a die-cast product instead of a mold, a shielding effect can be obtained. Therefore, in this case, the installation of the shield cap 16 can be omitted.

Further, the flexible diaphragm 12 is formed of a thin metal plate, a mylar plate, or the like, and has the function of highly sensitively transmitting the audio bone vibrations input to the acoustic vibration transmission plate 15 to the piezoelectric element 13. Note that by appropriately selecting the size and shape of the diaphragm 12 or the thickness of the diaphragm 12, it is possible to provide filter characteristics that cut out vibrations in unnecessary frequency bands below audible frequencies.

The piezoelectric element 13 may be made of tourmaline, quartz, Rothsiel salt, ceramics, or other known piezoelectric materials.

The acoustic vibration transmission plate 15 is brought into contact with the temporal region behind the ear, and has a concavely curved outer surface so as to be in close contact with the temporal region and transmit bone vibrations with high sensitivity.

Further, the elastic coating 17 softens the impact input from the outside and prevents the shock wave from acting on the piezoelectric element 13, thereby preventing disturbance of bone vibration waves. Furthermore, near the opening of the casing 11, the elastic coating 17 protrudes a little and extends to the vicinity of the outer periphery of the acoustic vibration transmission plate 15 to form a lip shape, and by coming into close contact with the temporal region, external noise can be reduced. Intrusion into the housing 11 is prevented.

In the bone conduction microphone 6 having such a configuration, sound vibrations transmitted to the temporal bones of the temporal region during vocalization are transmitted from the acoustic vibration transmission plate 15 to the piezoelectric element 13 via the diaphragm 12, and this piezoelectric element 13 is subjected to crystal strain. and a polarization voltage is generated between the diaphragm 12 and the diaphragm 12,
This change in polarization voltage can be extracted to the outside as a change in the audio signal. Then, this audio signal undergoes necessary sound quality correction and is output to an external headphone or the like so that it can be listened to.

In addition, if this bone conduction microphone 6 is installed on the sliding adjustment rod 5 as described above, it will not block the ear hole, so even if one ear is blocked by a headphone, external sounds and field work can be heard. Since the noise can be heard, the above-mentioned conventional dangers are eliminated.
In addition, bone conduction microphones only detect bone vibrations and do not detect external sounds or noise, so they can extract only clear audio signals and completely prevent overhearing of conversations.

FIG. 4 shows another embodiment. The housing 11A is molded from synthetic resin or the like so that the cross section is H-shaped, and the front part is provided with a diaphragm 12, piezoelectric element 13, and acoustic vibration transmission plate 15 as described above, and the rear part is equipped with a resistor and a vibration plate 15. Voltage detection device 2 that detects and amplifies piezoelectric signals including impedance conversion elements such as semiconductors
1 or other sound quality correction devices.
Further, a cover plate 22 is fitted into the rear open end of the housing 11A to prevent dust from entering. Reference numeral 23 denotes a guide groove for a lead wire 26 provided on the rear peripheral wall of the housing 11A, and the end of the lead wire 26 is connected to the circuit of the voltage extraction device 21 described above.

The bone conduction microphone 6A having such a configuration has the effects of the bone conduction microphone 6 described above, as well as voltage detection and sound quality correction in a compact housing 11.
Since this can be done within A, the effect can be obtained that it can be used as a microphone as is by simply connecting the end of the lead wire to an external standard circuit.

As detailed above, according to the present invention, a flexible diaphragm is provided on the casing so as to close the opening thereof, and a piezoelectric element is affixed to the inner surface of the flexible diaphragm. In addition, by attaching the acoustic vibration transmission plate 15 that is pressed against the temporal region on the outer surface, it is possible to transmit sound vibrations during vocalization to the piezoelectric element 13 with high sensitivity. The signal-to-noise ratio of the polarization voltage has been improved, making it possible to hear clear audio signals from other headphones.

In addition, by applying a shield cap or a coating such as rubber to the outer periphery of the casing, it is possible to prevent induction disturbances caused by external electrical and magnetic signals, and to effectively prevent vibrations caused by external forces from being transmitted to the piezoelectric element. is obtained.

[Brief explanation of drawings]

FIG. 1 is a front view of a handset equipped with a bone conduction microphone of the present invention, FIG. 2 is a partial side view of the same, FIG. 3 is a sectional view showing an embodiment of the bone conduction microphone, and FIG. The figure is a sectional view of another embodiment. 11, 11A... Housing, 12... Flexible diaphragm, 13... Piezoelectric element, 15... Acoustic vibration transmission plate, 16... Shield cap, 17... Elastic coating.

Claims (1)

[Scope of utility model registration request] The peripheral edge of the flexible diaphragm is fixed to the inner circumferential surface of the housing opening, a piezoelectric element is attached to the inner surface of the flexible diaphragm, and a piezoelectric element is attached to the outer surface of the flexible diaphragm. A bone conduction microphone to which an acoustic vibration transmitting member is fixed.