Oscillatory wave drive device and optical apparatus

An oscillatory wave drive device comprising:

• an oscillatory wave driving unit having an electromechanical energy conversion element having at least two drive phase electrodes and a detection phase electrode, an elastic body, and a rotor,
• a drive phase power output unit which supplies a drive phase voltage to the oscillatory wave driving unit,
• a drive phase voltage step-down unit which steps down the voltage to be supplied,
• a detection phase voltage step-down unit which steps down a detection phase voltage detected through the detection phase electrode,
• a phase difference detecting unit which detects a phase difference between the drive phase voltage and the detection phase voltage, and
• a control unit which controls the drive phase power output unit according to an output of the phase difference detecting unit,
• wherein alternating voltages different from each other in phase are applied to the two drive phase electrodes of the electromechanical energy conversion element to thereby generate a traveling wave on a surface of the elastic body, the rotor is driven by the traveling wave, and a drive state of the rotor is controlled by the control unit at least based on a signal of the phase difference detecting unit, and
• the detection phase voltage step-down unit and the drive phase voltage step-down unit each contain a resistance voltage dividing circuit having at least two resistors, and a voltage dividing ratio in the resistance voltage dividing circuit of the detection phase voltage step-down unit is lower than 1/1 and higher than 1/20.