Surgace Micromachined Dif-ferential Microphone


Surface Micromachined Dif-ferential Microphone


This invention consists of a differential mi-crophone having a perimeter slit formed around the microphone diaphragm that replaces the backside hole previously re-quired in conventional silicon, microm-achined microphones. In typical microm-achined microphones, it is necessary to in-corporate a significant volume of air behind the microphone diaphragm in order to pre-vent the back volume air from impeding the motion of the diaphragm. The air behind the diaphragm acts as a linear spring whose stiffness is inversely proportional to the nominal volume of air. In order to make this air volume as large as possible, and hence reduce the effective stiffness, a through-hole is normally cut from the backside of the silicon chip. However, the invention enables the creation of the microphone that does not require this backside hole.




•  The use of a very small backing cavity is possible, thereby obviating the need for creating a backside hole.


•  Lower cost since no secondary machining operation for creating backside holes is necessary



US 7,992,283, 8,214,999, 8,276,254, PCT/US2007/01915, South Korea 2008-7021002

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