PIEZOELECTRIC RESONATOR, AND PIEZOELECTRIC FILTER, DUPLEXER, AND COMMUNICATION APPARATUS USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a piezoelectric resonator or the like in which an influence of sprious vibration is extremely reduced. SOLUTION: In the piezoelectric resonator having a substrate 2 and a vibrator, formed on the substrate 2, having a structure holding the upper and lower faces of a thin film portion having at least one or more piezoelectric thin films while confronting at least a pair of an upper electrode 6 and a lower electrode 5 in the direction of thickness, and the shape of an overlapping portion confronting the upper electrode 6 and the lower electrode 5 in the vibrator is a rectangle except for a square or a polygon equivalent or superior to a tetrahedron having parallel sides with a length equal to or smaller than about 10 times the oscillatory wavelength when viewed in the direction of the thickness and also having at least one or more portions in which the distance between opposing electrode edges varies. COPYRIGHT: (C)2003,JPO