Patent ID: 7382079

Claim:
A piezoelectric device for generating an acoustic signal, comprising: a piezoelectric element for converting an electrical signal into mechanical vibration; an expansion mechanism for expanding a displacement of the mechanical vibration generated by the piezoelectric element; and an acoustic vibration portion for transferring the displacement of the mechanical vibration expanded by the expansion mechanism as acoustic vibration, wherein the expansion mechanism comprises an elastic member, a vibration output member having a plate shape being more rigid than the elastic member, and a base member having a plate shape being more rigid than the elastic member and more massive than the vibration output member, the base member and the vibration output member face each other with the piezoelectric element interposed therebetween, one end portions of the base member and the vibration output member facing each other are connected by the elastic member, and the piezoelectric element is placed between one end of the vibration output member connected to the base member by the elastic member and a center of the vibration output member.