Grating only optical microphone

摘要

A micro-electro-mechanical system (MEMS) optical sensor including an enclosure having a top wall, a bottom wall and a sidewall connecting the top wall and the bottom wall. The sensor further including a compliant membrane positioned within the enclosure, which is configured to vibrate in response to an acoustic wave and having a grating formed therein. A reflector is formed directly on an inner surface of one of the bottom wall or the top wall of the enclosure. A light emitter is positioned within the enclosure along a side of the compliant membrane opposite the reflector, the light emitter is configured to transmit a laser light toward the grating and the reflector. A light detector is positioned along the side of the compliant membrane opposite the reflector, the light detector configured to detect an interference pattern of the laser light, which is indicative of an acoustic vibration of the compliant membrane.

主权项

1. An optical microphone comprising:
an enclosure having a top wall, a bottom wall and a sidewall connecting the top wall and the bottom wall; a compliant membrane suspended within the enclosure by a suspension member, the compliant membrane configured to vibrate in response to an acoustic wave and having a grating formed therein, and wherein the suspension member is formed from a material of the compliant membrane and extends along an entire length of at least one side of the compliant membrane; a reflector formed directly on an inner surface of one of the bottom wall or the top wall of the enclosure; a light emitter positioned within the enclosure along a side of the compliant membrane opposite the reflector, the light emitter configured to transmit a laser light toward the grating and the reflector; and a light detector positioned along the side of the compliant membrane opposite the reflector, the light detector configured to detect an interference pattern of the laser light after reflection from the reflector, wherein the interference pattern is indicative of an acoustic vibration of the compliant membrane.