Magnetic field applying device

Abstract

A compact magnetic field applying device rotates and holds a magnetic field generating member using a small-scale, light-weight vibration actuator. A permanent magnet applies a bias magnetic field on a magnetized information recording area of a magnetooptical disk, and is driven by a vibration actuator. When voltage is applied to a piezoelectric element of the vibration actuator, an annular elastic member generates a travelling wave due to a bending vibration in the perimeter direction of a groove on the elastic member. Because the elastic member and a moving member provided on the permanent magnet are pressed into contact by a coil spring, the permanent magnet rotates. When voltage is not applied to the piezoelectric element, because the elastic member and the moving member are pressed into contact, the permanent magnet is held in a specified rotational position.

Dependencies are inferred from the claim text.