Magneto-optical disk unit compatible with different two types of magneto- optical disks and a magnetic-field generator suitable thereof

摘要

A magneto-optical disk unit has a first magnetic-field generator for generating a magnetic field corresponding to a frequency in a recording signal frequency band and a second magnetic-field generator for generating DC magnetic fields of both north-seeking and south-seeking poles in a non-contact manner with a loaded magneto-optical disk. The first magnetic-field generator has a slider part for sliding over a loaded magneto-optical disk in a floating manner using an aerodynamic effect. The unit further has a transfer driver for moving the first and second magnetic-field generators in a direction parallel to the loaded magneto-optical disk and a rotary plate for vertically moving the first magnetic-field generator. The unit also has a disk judging circuit for judging whether the loaded magneto-optical disk is of a magnetic-field- modulation overwritable type (first type) or an erase-operation-required type (second type), and a controller for controlling the rotary plate to bring the first magnetic-field generator into contact with the loaded disk when this disk is of the first type and to keep it raised from the disk when this disk is of the second type. The second magnetic-field generator is used when the disk is judged to be of the second type.