Optical microphone

摘要

An optical microphone for detecting an acoustic wave propagating through an environmental fluid by using a light wave, includes: an acoustic wave receiving section having a propagation medium portion through which an acoustic wave propagate and a first support portion for supporting the propagation medium portion; a light source for outputting a light wave so that the light wave passes through the propagation medium portion across the acoustic wave propagating through the propagation medium portion; a light-blocking portion having an edge line for splitting the light wave having passed through the propagation medium portion into a blocked portion and a non-blocked portion; and a photoelectric conversion section for receiving a portion of the light wave having passed through the propagation medium portion which has not been blocked by the light-blocking portion to output an electric signal.

主权项

1. An optical microphone for detecting an acoustic wave propagating through an environmental fluid by using a light wave, the optical microphone comprising:
an acoustic wave receiving section including a propagation medium portion and a first support portion, wherein the propagation medium portion is formed by a solid propagation medium, has an incidence surface through which the acoustic wave enters, and allows the acoustic wave having entered through the incidence surface to propagate therethrough, and the first support portion has an opening for the acoustic wave and supports the propagation medium portion so that the incidence surface is exposed through the opening; a light source configured to output a light wave so that the light wave passes through the propagation medium portion across the acoustic wave propagating through the propagation medium portion; a light-blocking portion having an edge line parallel to the incidence surface of the propagation medium portion for splitting the light wave having passed through the propagation medium portion into a blocked portion and a non-blocked portion; and a photoelectric conversion section configured to receive a portion of the light wave having passed through the propagation medium portion which has not been blocked by the light-blocking portion to output an electric signal, wherein: a +1st-order diffracted light wave and a −1st-order diffracted light wave of the light wave are generated through the propagation medium portion due to a refractive index distribution of a propagation medium of the propagation medium portion caused by the propagation of the acoustic wave therethrough; and the photoelectric conversion section detects at least a portion of one of an area of a 0th-order diffracted light wave having passed through the propagation medium portion with no diffraction which overlaps the +1st-order diffracted light wave and an area thereof which overlaps the −1st-order diffracted light wave, or detects both of these areas with different amounts of light.