Tracking Actuator for Magneto-optical Disk Drives

This paper describes the development of the tracking actuator for high-speed magneto-optical disk drives. The rotating mirror tracking actuator suspended by a single leaf spring is adopted. The actuator is required to have a fine mechanical vibration characteristics, which enables precise control against the high speed rotation of disks for high speed data transfer. However, in this kind of suspension, the higher order mechanical resonances by the spring deformation occurs in relatively low frequencies and reduce the tracking control frequency range. The novel method for suppressing the second order mechanical resonance, in which the drive force is added at the resonance's nodal point, is discussed. And its efficacy is experimentally confirmed. As a result, the higher order mechanical resonances do not appear up to 40 kHz, because the second resonance is successfully suppressed. The damping effect of the viscoelastic layer on the leaf spring is also clarified.