Patent ID: 8008840

Claim:
A drive unit, comprising: a vibrator having a piezoelectric body; a drive power supply configured to apply a driving voltage at a predetermined frequency to the vibrator such that vibration including stretching vibration and bending vibration is generated in the vibrator; a relatively movable element which is movable relative to the vibrator according to the vibration of the vibrator; and a driver element fixed to one of the outer surfaces of the vibrator which is crossing the direction of the bending vibration, wherein the vibrator drives the relatively movable element in a direction of the stretching vibration, and a difference between a resonance frequency of the bending vibration of the vibrator and an anti-resonance frequency of the stretching vibration of the vibrator is smaller than a difference between the resonance frequency of the bending vibration of the vibrator and a resonance frequency of the stretching vibration of the vibrator.