Patent ID: 7868942

Claim:
A driving device comprising: a vibrated member; a piezoelectric member which vibrates the vibrated member; a first driving electrode formed on a first surface of the piezoelectric member; a second driving electrode which is formed on a second surface of the piezoelectric member, the second driving electrode is formed in opposed position from the first driving electrode; a vibration detection electrode formed on the first surface of the piezoelectric member separately from the first driving electrode; a ground electrode formed on the second surface of the piezoelectric member separately from the second driving electrode, the ground electrode is formed in opposed position from the vibration detection electrode; a control circuit configured to be connected to the first and second driving electrodes, configured to cause the second driving electrode to be connected to a ground when a voltage is applied to the first driving electrode, and configured to cause the first driving electrode to be connected to the ground when a voltage is applied to the second driving electrode; and a resonant frequency detection unit configured to be connected to the vibration detection electrode and configured to detect resonant frequencies of the vibrated member, wherein a standing wave is appeared in the vibrated member when the control circuit applies voltage to the first driving electrode or second driving electrode, wherein the piezoelectric member is bonded to the vibrated member so that the piezoelectric member overlaps one of a plurality of antinodes of the standing wave, and wherein a length of the piezoelectric member in a short-side direction is equal to or smaller than half the wavelength of the standing wave.