| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact piezoelectric vibrating element having a high Q value and reduced spurious such as inharmonic overtone or higher-order contour vibration.SOLUTION: The energy-trapping piezoelectric vibrating element for thickness vibration includes a rectangular piezoelectric vibration substrate 5 having a vibration area, and first excitation electrodes 11a, 11b formed in the vibration area on a main surface of the piezoelectric vibration substrate. The piezoelectric vibration substrate 5 includes, at least in the vibration area of one main surface, a first plane portion 5a located at least on the outer diameter side, and a projecting portion located on the inner diameter side, projecting outward in the thickness direction. The projecting portion includes a substantially oval second plane portion 5b projecting more outward in the thickness direction than the first plane portion, and a substantially oval third plane portion 5c located on the inner diameter side and projecting outward in the thickness direction. The outer shapes of the second and third plane portions constitute at least a part of the contour lines of the oval shapes, and the middle points of the line segments connecting the focal points are located at the center of the vibration areas. |
