Enhanced Methods For Automatic Handling Of Optical Disks Housed In Cartridges

Abstract

An optical disk recording and playback system was developed for mass data storage which utilizes 14 inch diametyy disks permanently housed in cartridges. Sixty-eight disks with a storage capacity of 10 user bits per side per disk are located in storage and may be accessed within six seconds or less. To access a disk, a cartridge is cycled from storage, through a transport position and then onto a load station. From this position, the disk is loaded onto a turntable where digital data may be accessed at a ratelof 100 Mb/s. The enhanced approach utilizes the previously reported upon jukebox concept , however, with an optimized system approach. All optical elements, as well as the translation stage, which dynamically positions the focusing head, are located above the optical table for ease of accessibility and maintainability. The disk itself is suspended and sealed in a .32 inch thick cartridge. The profile of the cartridge is ideally suited for mass storage applications, where volume growth of stored cartridges is only limited by practical considerations. The active area of the disk is completely enclosed, except during data access times, when the dust seals are removed from actual disk contact. The spindle that rotates the disk is supported on porous graphite air bearings while the disk itself is held in place via vacuum. The optical table, which supports all of the recorder's critical static and dynamic components, was designed to be isolated from external perturbations, as well as from on-table generated and then transmitted vibrations. The paper describes mechanism design, dynamic test results obtained in the handling of optical disks i cartridges, as well as the growth potential to a double-sided disk and write/read rates significantly beyond 100 Mb/s.