Wide range audio transducer using piezoelectric ceramic
Hugo Schafft · Ferroelectrics · 1976
Piezoelectric circular bending transducers, when properly applied to loudspeakers, can cover a large portion of the audio spectrum and can deliver medium to high power outputs efficiently. In the concept presented in this paper, the bending transducers are mounted circumferentially and are loaded in the center by the cone. The transducers, which have a convex cross-section, are optimized for electro-mechanical coupling factor, capacitance and mechanical impedance. Maximum overall conversion efficiently is achieved through resistive electrodes, which also provide a frequency dependent sliding excitation. Two major problems, stress and field depoling, have been reduced by the transducer design and by the selection of the proper PZT compositions.