Resonator, unit having resonator, oscillator having unit and electronic apparatus having oscillator

摘要

A resonator comprises a base portion and a plurality of vibrational arms connected to the base portion and vibratable in a flexural mode. An electrode is disposed on at least one of opposite side surfaces of each of the vibrational arms so that a capacitance ratio r₁ of a fundamental mode of vibration of the resonator is less than a capacitance ratio r₂ of a second overtone mode of vibration thereof. A groove is formed in at least one of opposite main surfaces of each of the vibrational arms, and at least one mounting arm protrudes from the base portion.