Reduced height magnetic bias apparatus for a magnetooptical disk drive including a coil means having a central axis perpendicular to the rotating axis of a rotatable magnet

摘要

A magnetic bias apparatus for generating a magnetic field for recording or erasing information in the magnetooptical disk drive apparatus is disclosed. The magnetic bias apparatus has a permanent magnet for generating a bias magnetic field which is rotatable about a rotating axis, a coil for rotating the permanent magnet and a circuit for driving the coil. The central axis of the coil is directed toward the rotating axis parallel to the plane of a magnetoptical disk and perpendicular to a plane of the permanent magnet defined by the two poles and extending through the central axis. The apparatus can be constructed in a reduced height while the permanent magnet can be rapidly rotated.