Optical microphone
US6014239A · kind A · utility
30Cited by
7References
11Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Dec 12, 1997 |
| Grant date | Jan 11, 2000 |
| Priority date | — |
| Expiry date | Dec 12, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R23/008
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical microphone includes a laser and beam splitter cooperating therewith for splitting a laser beam into a reference beam and a signal beam. A reflecting sensor receives the signal beam and reflects it in a plurality of reflections through sound pressure waves. A photodetector receives both the reference beam and reflected signal beam for heterodyning thereof to produce an acoustic signal for the sound waves. The sound waves vary the local refractive index in the path of the signal beam which experiences a Doppler frequency shift directly analogous with the sound waves.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.