A new tracking system for magneto-optical disk drives —Part I: Design

To reduce the average accessing time of a magneto-optical (MO) disk drive, which is a severe drawback of current products, a newly developed moving-magnet type tracking actuator has been implemented and will be tested. The moving-magnet type actuator meets the following objectives which the known prior actuator designs have not been able to satisfy: providing sufficiently high magnetic force constants over essentially the whole stroke length of the actuator, achieving extremely rapid accessing time while providing a mechanically stiff carriage; eliminating the carriage thermal expansion which causes a head misalignment on disk tracks; eliminating flexible cable connections to the moving parts; providing a very compact design, and reducing the cost of manufacturing. Computer aided design using magnetic circuit theory is applied for determining optimal design parameters for the actuator.