Phone-or Ltd.

Okihiro Kobayashi

Alexander Paritsky

Alexander Kots

Kazuo Takahashi

Nobuhiro Miyahara

A communication helmet having an enhanced noise reduction effect. The communication helmet incorporates a microphone disposed in the vicinity of the mouth of the speaker wearing the helmet. The microphone is an optical microphone comprising a diaphragm ( ) vibrating with sound pressure, a case ( ) containing the diaphragm ( ) and having a first opening ( ) and a second opening ( ) open in symmetric positions and facing the diaphragm ( ), a light source ( ) for projecting a light beam to the diaphragm ( ), and a photodetector ( ) receiving part of the reflected light of the light beam projected to the diaphragm ( ) and outputting a signal corresponding to the vibration of the diaphragm ( ). The optical microphone is fixed to a fixing base ( ) at a predetermined angle so that the incoming sound wave may uniformly enter the first opening ( ) and the second opening ( ). The fixing base ( ) is attached to the helmet with a space so that the external sound wave may uniformly enter the first opening ( ) and the second opening ( ).

Communication helmet

A device for collecting sounds from objects comprises a plurality of microphones whose directivity can be varied depending on the environment in which each object is located. An optical microphone includes a vibration board ( ) which vibrates by sound pressure, a light source ( ) for emitting a light beam to the vibration board ( ), a photodetector ( ) which receives the light beam reflected from the vibration board ( ) and produces a signal corresponding to the vibration of the vibration board ( ), a drive circuit ( ) for supplying the light source ( ) with predetermined current, and a negative feedback circuit ( ) that supplies the drive circuit ( ) with a negative feedback signal consisting of a signal output from the photodetector ( ). The negative feedback circuit ( ) changes the amount of negative feedback depending on the environment.

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Tokyo, Japan

Okihiro Kobayashi