Innovative three-axial actuator for high-density optical drive

As the density in optical data storage systems increases, a drive capable of tilt control thus becomes necessary in order to improve the tilt margin as the coma aberration is accordingly increased. In this paper, we propose an innovative three-axial actuator based on a traditional four-wire scheme with an additional pair of tilting magnets. The proposed coil-driven servo can independently compensate ± 1 tilt degree associated with a torque variation of less than 5 %. The driving forces of the focusing and tracking are kept constant while the tilt servo is activated.