JPH0761186B2 - Bone conduction microphone - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable microphone, and more particularly to a bone-conduction microphone capable of picking up only a voice uttered by a wearer to improve the communication quality without being affected by ambient noise.

[0002]

[Prior Art] Airports, car races, concert venues,
When it is necessary to make a call using a microphone near a noise source such as an engine room of a ship or a construction site, a noise resistant microphone that removes the influence of noise and picks up only the voice of the user has been used. Has been done. As such noise-resistant microphones, there are bone-conduction microphones such as a vibration-type throat microphone, an ear bone microphone, and a nose bone microphone in addition to the sound pressure type close-talking microphone.

The sound pressure type microphone is a microphone for directly picking up the sound pressure emitted from the mouth at the time of utterance, and bone-conducting microphones such as a throat microphone, an ear bone microphone, and a nose bone microphone are used for throat, ear bone, It directly picks up the vibration of the nose and the like and converts this vibration into an electric signal.

However, since the above sound pressure type microphone is generally used while being held at a position separated from the mouth of the user, a sound pressure type transducer having an impedance relatively close to the acoustic impedance of air is used. It was easy to pick up external noise, and it was difficult for the listener who was the other party to identify the voice. In addition, the bone conduction microphone can be used when the wearer moves the head or other body.
There is a defect that it is easy to pick up the contact broadband noise generated by friction with the body part where the microphone is fixed, and the S / N ratio is lowered.

Further, when a wireless communication device using such a microphone and having an automatic transmission / reception switching function is used under high noise, the automatic switching function is apt to malfunction. there were.

From this point, the present inventor has found that
In JP-A 1-155470, a vibration-sensitive transducer having a high acoustic impedance is closely fixed to a sound-receiving plate having an appropriate hardness, so that noise propagating as a sound wave outside the living body, which is a voice source, is not substantially detected. , Proposed a noise-resistant microphone that converts the vibration propagating through the bones that make up a living body into an electrical signal. According to this noise resistant microphone, it is not sensitive to the vibration propagating through the air, and therefore, the noise resistant microphone (for example, 120d
When applied to a wireless communication device or the like used in B) or more), noise can be removed and a clear voice call can be made.

However, the throat microphone shown in the above patent application is used by pressing the sound receiving block against the pharyngeal bone by wrapping the belt having the sound receiving plate fixed with the transducer around the neck of the user. For this reason, the trachea and blood vessels are compressed, causing suffocation, discomfort, and the inability to withstand long-term use.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to eliminate the above-mentioned conventional drawbacks, and provides a bone-conduction microphone using a vibration-sensitive transducer having high acoustic impedance.
A bone conduction microphone that eliminates discomfort caused by tightening the neck by connecting to the microphone holder such as the user's helmet and headphones and pressing the microphone body against the pharyngeal bone etc. only during a call. Is intended.

[0009]

SUMMARY OF THE INVENTION To achieve the above object, the present invention substantially detects noise propagating as a sound wave outside a living body by closely fixing a vibration-sensitive transducer to a sound-receiving plate having an appropriate hardness. In a bone-conduction microphone that electrically converts vibration propagating through bones that form a living body, a microphone body that houses a transducer fixed to one surface of a sound receiving plate, and a microphone that extends from the microphone body A microphone holder for suspending the main body from a helmet or the like, the microphone main body stores and seals the transducer in an elastic case, and the other surface of the sound receiving plate forms a part of an outer wall of the case. It is composed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to the embodiments shown in the drawings.

FIG. 1 is a perspective view showing an embodiment of a bone conduction microphone according to the present invention, and FIGS. 2 (a) and 2 (b) are sectional views of the microphone body.

This bone-conducting microphone comprises a microphone body 1 and a microphone holder 6 for holding the microphone body 1, and is used by suspending it from a holder such as a helmet or headphones worn on the head of the wearer. .

The microphone main body 1 is a vibration-sensitive transducer (for example, a piezoelectric element) which is closely fixed to one surface of a sound receiving plate 4 having an appropriate hardness and shape inside a hollow case 2 made of rubber or resin which is easily elastically deformed. (Acceleration sensor 5) is hermetically housed, and the other surface of the sound receiving plate 4 forms a part of the outer wall of the case 2.

A portion 6a corresponding to about half of the entire length of the microphone holder 6 extending from the microphone body 1 and connected to the microphone body 1 is a flexible tube made of rubber or the like, and a headphone (not shown) is provided. The other half 6b to be connected to etc. is a rubber tube into which a relatively rigid pipe such as metal is inserted, and a male pipe for fixing one end of the microphone holder 6 to the headphone etc. at the tip of the rigid pipe. The screw 7 is provided.

The tab-shaped projection 8 extending from the outer wall of the case 2 of the microphone body 1 is a "knob" when the microphone is used, and the sound-accepting plate 4 is gripped with a finger and the sound-accepting plate 4 is a part of a jaw or a throat bone. It is provided so that it can be easily pressed.

By the way, since the acoustic impedance of the transducer of the above-mentioned type is originally extremely large (about 10 ⁶ times) that of air, it is hardly affected by noise propagating in air as a medium. The case 2 for accommodating the transducer also has a sound absorbing effect, and the microphone holder 6 for connecting the case 2 (microphone body) to a helmet or the like is also a part of a flexible tube. Even if a force is applied, this will not cause the transducer 5 to vibrate and emit a signal.

By the way, the transducer 5 converts the picked-up vibration into an electric signal, and this electric signal is output to a transmission circuit mounted on a helmet or the like through a lead wire passing through the microphone holder 6. If the power is always turned on, when the microphone body 1 suspended from a helmet or the like swings when not talking, it collides with or rubs against the human body or a fixed object around it, and noise is transmitted from the transmission circuit to the reception side. There is a problem with the transmission. As a method for solving such a problem, it is effective to insert a voice switch in the transmission circuit and pick up and transmit only the voice uttered by the carrier.

Further, in order to further prevent noise transmission during non-call by transmitting the signal generated by the transducer 5 only during a call, it is preferable to configure this microphone in a press-talk type.

That is, FIG. 3 is an external view showing a second embodiment of the bone-conduction microphone according to the present invention, and FIG. 4 is an explanatory view of the internal structure of the elastic body case in which the sound receiving plate 4 is removed together with the transducer 5. FIG. 5 is a cross-sectional view taken along the line AA of FIG. 4, in which a micro switch 9 is housed in addition to a vibration sensitive transducer 5 using a piezoelectric element inside a hollow elastic case 2 that constitutes the microphone body 1. When the button 10 provided on the wall surface of 2 is pressed when the microphone is used, the micro switch 9 is turned on and the signal generated by the transducer 5 is transmitted to a transmission system (not shown).

The button 10 is embedded with a pin that penetrates the outer wall of the elastic hollow case 2 to push the contact point of the micro switch 9, and the push on the pin is released by utilizing the rubber elasticity of the outer wall of the case 2. For example, it may be returned to the original position (position where the micro switch is turned off).

The bone-conduction microphone having the above-described structure is extremely effective when applied to, for example, a pharyngeal microphone.
In this case, the base end of the microphone holder 6 is hung on a holding tool such as a helmet or headphones by means of screwing or the like, and the knob 8 is picked up with a fingertip only during a call so that the acrylic plate is lightly attached to the side of the larynx. It suffices to press the sound receiving plate 4 such as to make a call. Needless to say, when using the microphone having the switch shown in the second embodiment, the user speaks while turning the button 10 on.

It is also possible to use the microphone of the present application to pick up a sound by utilizing the vibration of a region other than the pharyngeal bone, for example, the bones of the cheek or the jaw. In this case, the length of the microphone holder 6 is It may be set in advance according to the contact area of the microphone body. In the claims, "pharyngeal bone, etc." is a concept including bones located in the head, such as pharyngeal bone, cheekbone, jawbone, etc., and the present invention on the skin corresponding to the positions of these bones. It refers to a body part that makes it possible to pick up sound by bringing a bone conduction microphone into contact.

As described above, the bone-conduction microphone of the present invention can be used by pressing it on the pharyngeal bone or the proper place on the face simply by changing the length of the microphone holder, and the sound receiving plate can be wound around the user's neck. Since it is not constantly pressed against the pharyngeal bone, it is possible to eliminate all the drawbacks that the trachea and blood vessels are compressed, causing stuffiness and discomfort, and being unusable for a long time. In addition, it is almost insensitive to vibrations propagating through the air, and therefore is noisy under high noise (for example, 120 dB).
When applied to a wireless communication device used in the above), noise can be removed and a clear voice call can be made.

The above-mentioned transducer may be of any type as long as it is a vibration-sensitive type having a high acoustic impedance, and the material of the sound receiving plate is not necessarily limited to acrylic, and it may be a high acoustic impedance. Any material may be used.

[0025]

As described above, according to the present invention, in a bone-conduction microphone using a vibration-sensitive transducer having a high acoustic impedance, a holder or a narrow space which is worn on the human body such as a user's helmet and headphones. By suspending it from an appropriate place inside the axle etc. and pressing the microphone part against the pharyngeal bone etc. only when talking, you can eliminate the discomfort caused by tightening the neck and enable high quality talking in noise. Has a remarkable effect on

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a bone conduction microphone according to the present invention.

2A and 2B are cross-sectional views of a microphone body, respectively.

FIG. 3 is an external view showing a second embodiment of the bone conduction microphone according to the present invention.

FIG. 4 is an explanatory diagram of an internal configuration of an elastic body case with a sound receiving block and a transducer removed.

5 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

1 ... Microphone body 2, 3 ... Elastic case, 4 ...
・ Acrylic block (sound receiving block), 5 ... Vibration sensitive transducer (acceleration sensor), 6 ... Microphone holder, 9 ... Switch member,

Claims (2)

[Claims] 1. A sound receiving plate having a suitable hardness and a shape suitable for pressing in a suitable position near the oral cavity or throat , and
Vibration-sensitive transducer fixed to one side of the sound receiving plate
And an elastic body for accommodating the vibration-sensitive transducer
A case, and the other surface of the sound receiving plate is the elastic body case.
And a microphone main body configured to form a part of the outer wall of the microphone, and the microphone main body is hung from a holder worn on the head by a user so that the microphone main body can be used by pressing it against the pharyngeal bone or the like only during a call. A bone conduction microphone characterized by having a flexible microphone holder for lowering. 2. The microphone main body is provided with a button switch for press talk, and the microphone main body is pressed against the pharyngeal bone or the like while being pressed during a call so that the microphone can be used. 1. The bone conduction microphone according to 1.