Optical sensing in a directional MEMS microphone
AssigneeState University of New York
InventorsRonald Miles, F. Degertekin
Life of this patent
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Abstract
A microphone having an optical component for converting the sound-induced motion of the diaphragm into an electronic signal using a diffraction grating. The microphone with inter-digitated fingers is fabricated on a silicon substrate using a combination of surface and bulk micromachining techniques. A 1 mm×2 mm microphone diaphragm, made of polysilicon, has stiffeners and hinge supports to ensure that it responds like a rigid body on flexible hinges. The diaphragm is designed to respond to pressure gradients, giving it a first order directional response to incident sound. This mechanical structure is integrated with a compact optoelectronic readout system that displays results based on optical interferometry.
Claims20
A directional microphone, comprising:
- a) a substrate having a microphone disposed thereon, said microphone having a differential, MEMS microphone diaphragm supported by two pivot points;
- b) a light source for generating coherent light, said light source being disposed in operative relationship with said diaphragm;
- c) means for detecting reflected light generated by said light source;
- and
- d) photodetection electronics operatively connected to said means for detecting reflected light, for generating an electrical signal representative of said microphone.
A directional microphone, comprising:
- a) a differential microphone diaphragm having an optical grating;
- and
- b) means in operative relationship to said diaphragm for optical interferometrically detecting motion thereof.
A hearing aid comprising a directional microphone, said microphone comprising diaphragm having an optical grating, and means in operative relationship to said diaphragm for optical interferometrically detecting motion thereof.
Dependencies are inferred from the claim text.