Patent ID: 8633788

Claim:
A vibration piece comprising: a base; a vibration arm that extends from the base; a groove that is formed in an arm principal surface of the vibration arm along a longitudinal direction of the vibration arm; an inner electrode that is formed on an inner surface of the groove and that has a first polarity; a side electrode that is formed on an arm side surface of the vibration arm and that has a second polarity that is different from the first polarity; and a widening portion that is formed at a junction of the base and the vibration arm, a width of the widening portion being widened toward the base; wherein a part of the side electrode extends onto a part of the arm principal surface; and wherein the widening portion extends over the base and includes a first widening portion and a second widening portion, the first widening portion having a different width than the second widening portion.