Stage device, minute operation device, and method of controlling same

A minute operation device comprising:

• an object to be driven;
• a vibration actuator including a vibration element having an elastic body and an electromechanical energy conversion element, and a contact body in contact with the vibration element, one of the vibration element and the contact body being fixed at a predetermined position, and the other being a movable body which is movable in a predetermined direction and is also connected to the object to be driven, the vibration actuator being configured to drive the object to be driven in the predetermined direction;
• and
• a control unit configured to perform control such that the movable body is moved or vibrated in the predetermined direction by applying two-phase AC voltages to the electromechanical energy conversion element to thereby excite predetermined vibrations in the vibration element,
• wherein the control unit causes the vibration actuator to be driven such that an operation mode is switched between a movement mode for moving the object to be driven in the predetermined direction and a vibration mode for vibrating the object to be driven in the predetermined direction,
• wherein an absolute value of a phase difference between the two-phase AC voltages in the movement mode is larger than 0° and not larger than 90°, and
• wherein the phase difference between the two-phase AC voltages in the vibration mode is +180° or −180°.

A method of controlling a minute operation device that drives a vibration actuator including a vibration element having an elastic body and an electromechanical energy conversion element, and a contact body in contact with the vibration element, one of the vibration element and the contact body being fixed at a predetermined position, and the other being a movable body which is movable in a predetermined direction and is also connected to an object to be driven, to thereby drive the object to be driven in the predetermined direction, the method comprising:

• moving the object to be driven to a predetermined position by driving the movable body through application of two-phase AC voltages to the electromechanical energy conversion element to thereby excite predetermined vibrations in the vibration element;
• and
• vibrating, in a state in which the object to be driven is in the predetermined position, the object in the predetermined position in the predetermined direction through application of two-phase AC voltages to the electromechanical energy conversion element to thereby vibrate the vibration element in the predetermined direction,
• wherein an absolute value of a phase difference between the two-phase AC voltages in the movement mode is larger than 0° and not larger than 90°, and
• wherein the phase difference between the two-phase AC voltages in the vibration mode is +180° or −180°.