Optical unit, image pickup apparatus, endoscope and driving method of optical unit

A driving method of an optical unit, comprising:

• when moving a moving barrel held at a first position by a first magnetic force of a first magnet to a second position, passing a current in a predetermined direction to a coil to cause the coil to generate a second magnetic force stronger than the first magnetic force, attracting a second magnet provided at the moving barrel by the second magnetic force to move the moving barrel to the second position, and holding the moving barrel at the second position by the second magnetic force;
• and
• when moving the moving barrel to the first position from the second position, passing a current in an opposite direction to the predetermined direction to the coil for only a predetermined time, inverting the second magnetic force to attract the second magnet of the moving barrel by a repulsion force to move the moving barrel to the first position, and holding the moving barrel at the first position only by an attraction force by the first magnetic force of the first magnet after stopping energization to the coil,
• wherein
• the moving barrel is accommodated in a fixed barrel to be able to advance and retract between the first position and the second position,
• the first magnet is provided on a distal end side of the fixed barrel, and the coil is provided on a proximal end side of the fixed barrel,
• the optical unit includes a yoke configured to increase the magnetic field of the coil, and
• in a state in which the moving barrel is held at the second position, the yoke and the second magnet are placed at a position at which a distal end surface of the yoke and a proximal end surface of the second magnet correspond to each other in a direction orthogonal to an optical axis.