VIBRATION ELEMENT, VIBRATOR, ELECTRONIC DEVICE, OSCILLATOR AND ELECTRONIC APPARATUS

摘要

PROBLEM TO BE SOLVED: To suppress unnecessary vibration due to bending vibration generated in a mesa type vibration element, and to obtain a vibration element having a small CI value.SOLUTION: A vibration element is provided with a vibration substrate 10 and excitation electrodes 20a and 20b. The vibration substrate 10 has a vibration portion 14 and an outer edge portion 12. An entire outer peripheral edge of the vibration portion 14 is provided with step edge portions that have at least two stages and are gradually decreased in thickness toward the outer edge portion 12. When a number of stages of each step is represented by i, a length of each i-th stage step is represented by Mx, a length of each outermost side step is represented by Mx, a length of each excitation electrode is represented by Ex and a wavelength of bending vibration is represented by λ, respective parameters are set to satisfy both expressions of -0.2<((Mx-Mx)/2-nλ/2)/(λ/2)<0.2 (1) and -0.2<((Ex-Mx)-kλ/2)/(λ/2)<0.2 (2).