| 摘要 |
PURPOSE:To hold a movable element at, and return it to the neutral point by making a magnetic pole to be magnetized on the outer surface of a movable element and a magnetic pole of a yoke provided on the side of the center part of the movable element equal in polarity for making them to mutually repulse. CONSTITUTION:Electromagnetic force to drive a movable element 3 in the focusing direction is generated by a magnetic line of force generated from magnets 4 and 5 and a current flowing through a focusing coil 7. The electromagnetic force driving the movable element 3 in the tracking direction is generated by the magnetic line force generated from the magnets 4 and 5 and a current flowing through a tracking coil 9. At the time, a magnetic pole to be magnetized on the outer surface of the movable element 3 and a magnetic pole of a yoke 6 provided on the side of the center part of the movable element 3 are made equal in polarity for repulsing mutually. Thereby, the movable element is held at, and returned to the neutral point.
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