Optical sensing in a directional MEMS microphone
US7826629B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 19, 2006 |
| Grant date | Nov 2, 2010 |
| Priority date | — |
| Expiry date | Aug 21, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2201/003
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.