Kaoru Yasukawa

New flying optical head for high-speed accessing

A flying optical head has been developed to attain high speed accessing, the important issue in applying optical disks for computer file memories, because the head weight could be ultimately reduced. And it was successfully applied for writing and reading of optical disks for the first time. The moving part of the head consists of an objective lens, mirror, flying slider and moving coil of a voice coil motor and a linear bearing, which total weight is as light as 3.6gr. The flying slider makes the objective lens follow on a disk surface, so the variation of the distance between the lens and the optical disk caused by the axial runout of the disk is largely reduced. Autofocusing is done by axial moving of relay lenses which are placed in the fixed part of the head. The resonant frequency of the moving part has been improved to more than 10kHz by reducing its weight, which enables it to do track-following as well as track-seeking. Seek time of less than 20 ms for a 130mm disk was achieved with the flying optical head.