PIEZOELECTRIC TYPE SPEAKER

摘要

PROBLEM TO BE SOLVED: To suppress excessive amplitude in the central vicinity of a piezoelectric vibrator and to improve input resistance by providing visco-elastic bodies having a bottom area of a specified value range and small pieces made of a material in which at least either specific gravity or elastic modulus is higher than that of the visco-elastic bodies at the center parts of the visco-elastic bodies. SOLUTION: The visco-elastic bodies 5 having a bottom area of >=11% and <=80% of the area of a metal diaphragm 1 are pasted almost at the central parts of both faces of the piezoelectric vibrator, and the small pieces 7 made of a material in which at least either specific gravity or elastic modulus is higher than that of the bodies 5 are provided at the central parts of the bodies 5. Amplitude is suppressed by the pieces 7 in which the specific gravity or the elastic modulus is higher than that of the bodies 5 so that piezoelectric materials 2 can not be peeled off from the diaphragm 1 at excessive amplitude even with the bodies 5 pasted. Then, the pieces 7 can suppress the excessive amplitude of the central part of a piezoelectric vibrator 3 while a reproduced sound pressure frequency characteristic maintains flatness, and the input resistance can be improved without degrading the characteristic.