Patent ID: 7337667

Claim:
An angular velocity sensor comprising: a tuning fork vibrator including a first vibrating arm having a first end and a second end, the first vibrating arm having a fundamental vibration frequency, a second vibrating arm having a first end and a second end, the second vibrating arm having the fundamental vibration frequency, and a coupling portion for coupling the first end of the first vibrating arm to the first end of the second vibrating arm; a drive unit for causing the first vibrating arm to vibrate, the drive unit being provided on the first vibrating arm, the drive unit having a driving resistance; a detection unit for detecting an amount of deflection of one of the first vibrating arm and the second vibrating arm when deflecting due to an angular velocity applied to the tuning fork vibrator, the detection unit being provided on the one of the first vibrating arm and the second vibrating arm; and an auxiliary weight unit provided on the first vibrating arm and between the drive unit and the second end of the first vibrating arm, the auxiliary weight unit being separated from the drive unit and the detection unit, wherein the auxiliary weight unit includes a first electrode provided on the first vibrating arm, a piezoelectric layer provided on the first electrode, and a second electrode provided on the piezoelectric layer, and wherein a ratio R 1 /R 2 is smaller than “1”, where R 1 is the driving resistance at the fundamental vibration frequency, and R 2 is the driving resistance at a vibration frequency different from the fundamental vibration frequency.