Patent ID: 6051916
Filing Date: 2000-04-18
Classification: H03H

Abstract:
An energy-trap thickness extensional vibration mode piezoelectric resonator utilizing an nth-order harmonic of a thickness extensional vibration mode, comprising:a piezoelectric plate having first and second surfaces arranged opposite to each other;a first excitation electrode provided on said first surface of said piezoelectric plate;a second excitation electrode provided on said second surface of said piezoelectric plate and arranged to oppose said first excitation electrode with said piezoelectric plate disposed therebetween;at least one internal electrode disposed in said piezoelectric plate and located at least partially opposite to the first and second excitation electrodes;an opposing portion of said first and second excitation electrodes, said internal electrode and said piezoelectric plate defining a resonating portion;vibration-attenuating portions disposed on both sides of said resonating portion along only one direction of the piezoelectric plate;said first and second excitation electrodes extending substantially to both sides of the piezoelectric plate in a direction that is substantially perpendicular to said one direction in which said vibration-attenuating portions extend; andsaid piezoelectric plate is constructed to satisfy a relation L/d.ltoreq.14 in which d=t/n, where L is a length of said piezoelectric plate along said one direction and t is a thickness of said piezoelectric plate, and n is an integral larger than 1.