Actuator and coil unit

An actuator comprising:

• a movable unit configured to hold an object to be driven thereon;
• a fixed unit having a second loosely fitting face to be fitted into a first loosely fitting face of the movable unit;
• and
• a driving unit configured to make the movable unit electromagnetically drivable and rotatable with respect to the fixed unit,
• one of the first loosely fitting face or the second loosely fitting face having a recess, the other of the first loosely fitting face or the second loosely fitting face having a raised spherical face,
• a center of rotation of the movable unit being located on a fitting direction in which the raised spherical face is fitted into the recess,
• the driving unit including:
• a pair of first driving magnets provided for the movable unit on a first plane including a first axis and the fitting direction, the first axis being perpendicular to the fitting direction and passing through the center;
• a pair of first magnetic yokes facing the pair of first driving magnets and provided for the fixed unit such that a distance from the first magnetic yokes to the center is longer than a distance from the first driving magnets to the center;
• a pair of first drive coils wound around the pair of first magnetic yokes;
• a pair of second driving magnets provided for the movable unit on a plane including a second axis and the fitting direction, the second axis being perpendicular to the fitting direction and the first axis and passing through the center;
• a pair of second magnetic yokes facing the pair of second driving magnets and provided for the fixed unit such that a distance from the second magnetic yokes to the center is longer than a distance from the second driving magnets to the center;
• and
• a pair of second drive coils wound around the pair of second magnetic yokes,
• when the movable unit is in a neutral position in which the movable unit has rotated around neither the first axis nor the second axis, a first synthetic vector and a second synthetic vector being directed toward the object to be driven with respect to a second plane including the first axis and the second axis, the first synthetic vector being defined by synthesizing together two first vectors, pointing toward the first magnetic yokes, of magnetic attraction forces between the pair of first driving magnets and the pair of first magnetic yokes, the second synthetic vector being defined by synthesizing together two second vectors, pointing toward the second magnetic yokes, of magnetic attraction forces between the pair of second driving magnets and the pair of second magnetic yokes.