| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a thin-film resonator that excites lateral waves while at the same time suppressing the excitation of longitudinal waves at a predetermined frequency. <P>SOLUTION: The thin-film resonator 10 is such that n layers (n is a natural number of 3 or above) of piezoelectric layers (first piezoelectric layer 111, second piezoelectric layer 112, third piezoelectric layer...) are provided between a first electrode 121 and a second electrode 122. A polarization vector B in each piezoelectric layer is oriented to tilt about a normal line 13 of a plane α parallel to the thin-film resonator. The projection of the polarization vector P in each piezoelectric layer on the normal line 13 is in the same direction. The projections on the plane α of the polarization vectors P in odd-numberth piezoelectric layers counted from the first electrode 121 side orient in the opposite direction from the projections on the plane α of the polarization vectors P in the even-numberth piezoelectric layers counted from the first electrode 121 side. Due to this structure, excitation of a lateral wave having the largest intensity occurs at a different frequency from that of excitation of a longitudinal wave having the largest intensity, and hence excitation of longitudinal waves can be suppressed when lateral waves are excited. <P>COPYRIGHT: (C)2010,JPO&INPIT |
