Abstract
A microphone with simple construction, using a bimorph diaphragm made from a composite piezoelectric polymer sheet, is described. A composite of lead-titanatezirconate powder and polyvinylidenefluoride and/or fluorinated rubber is useful, because its characteristics can be widely controlled by varying its composition, and it is easy to mold into a sheet. A symmetric bimorph structure using two composite polymer sheets is convenient for the structure. Microphone response is calculated, and it is concluded that a microphone, some 10-20 mm in diameter, shows of -70∼-90 dB response (re volt/microbar) as a telephone microphone. Several experiments confirm these results.
