US Patent 7916879 Electrostatic acoustic transducer based on rolling contact micro actuator

An acoustic transducer is disclosed, which comprises a micro fabricated, sound generating, or receiving, diaphragm, a conductive leaf cantilever actuator, and a counter electrode. In the acoustic transducer, the electrostatic attraction force between the counter electrode and the leaf cantilever due to an imposed electrical potential is utilized to generate a deflection of the diaphragm attached to said cantilever. In operation, the cantilever collapses on to the counter electrode, causing a significant increase in actuator driving force due to the reduction, and partial elimination, of the air gap in the transducer.