Patent ID: 6459798
Filing Date: 2002-10-01
Classification: H04R

Abstract:
A sound collector collecting sound by changing directivities of a microphone according to an environment in which a sound collection object is located;wherein the above microphone is an optical microphone that comprises a diaphragm to vibrate by the sound pressure; an illuminant to irradiate an optical beam to the above diaphragm; a photodetector which receives a reflection light of the light beam irradiated in the diaphragm and which outputs a signal which copes with the oscillation of the diaphragm; an illuminant drive circuit to drive the illuminant to supply predetermined electric current; and a negative feedback circuit that supplies the signal outputted by the photodetector to the illuminant drive circuit as a negative feedback signal; and wherein the gain of negative feedback of the negative feedback circuit is changed corresponding to the environment.