Optical Differential Microphone


Optical Sensing in a Directional MEMS Microphone


This micro-machined differential microphone utilizes an optical means to convert the sound-induced motion of a diaphragm into an electronic signal. Because it can be manufactured with high sensitivity and low noise, this lightweight microphone design offers a means to improve hearing aids and cellular phone applications. This invention overcomes changes in capacitance performance limitations by using an optical detection scheme based on a low-power semiconductor laser and optical gratings incorporated into the microphone diaphragm.  Because the overall compliance of the microphone diaphragm is adjustable over a very wide range, it is possible to achieve high sensitivity and very low noise performance.




The optical design permits the use of much more flexible and smaller diaphragms, which can be made using silicon micro-fabrication techniques.


It achieves higher signal to noise ratios than are possible in capacitive sensing schemes.


It  has a much lower noise detection floor relatively low power consumption, and is lightweight.


Patent Information:
For Information, Contact:
Scott Moser
Binghamton University
Ronald Miles
F. Degertekin
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