A silicon microspeaker for hearing instruments

A micromachined loudspeaker for audible acoustic instruments is designed, fabricated and tested. A single loop voice coil on a flexible polyimide membrane is conceived to serve as the sound generating plate, and is driven by electromagnetic actuation. The diameter of the microspeaker is 5 mm x 5 mm, and it is fabricated by a low temperature micromachining process. At a driving voltage of as low as 1.5 V, the microspeaker output sound pressure level is 93 dB at 5 kHz when measured in a 2 cc volume.