Magnetooptic recording and erasing head which performs biasing, tracking and focusing

Claim 1

A magnetooptic head for recording/erasing information on/from a recording medium by irradiating the recording medium with a laser beam within a forward/reversed direction magnetic field, which comprises: (a) condenser lens means for focusing the beam on the recording medium; (b) four magnetic field generating means fixedly arranged outside said condenser lens means in such a manner that magnetization direction thereof is in a radial direction of said condenser lens means with magnetic poles thereof confronting each other at a center of said condenser lens means and having magnets placed at regular angular intervals around said condenser lens means, for generating a recording/erasing external magnetic field in an axial direction of said condenser lens means and focusing and tracking actuator magnetic fields in a radial direction of said condenser lens means; (c) at least two focusing coil means arranged within the radial-direction magnetic field in symmetrical positional relationship with respect to the center of said condenser lens means, for moving said condenser lens means and said magnetic field generating means together in an axial direction of the recording medium, for providing an automatic focusing servo operation of the laser beam; (d) at least two tracking coil means also arranged within the radial-direction magnetic field in symmetrical positional relationship with respect to the center of said condenser lens means, for moving said condenser lens means and said magnetic field generating means together in a radial direction of the recording medium, for providing a tracking servo operation of the laser beam; and (e) elastic means for supporting said condenser lens means and said magnetic field generating means together so as to be movable relative to said focusing tracking coil means in the axial and radial direction of said recording medium.