Stationary pick-up head for very fast seek in optical disk drives

Compared with hard disk drives (HDDs), Optical Disk (OD) drives are quite slow. Typical ODs offer average seek time in the range of 90 ms or longer, compared with 5 to 10 ms for HDDs. This is a direct result from the fact that optical pick-up heads are heavier by several orders of magnitude than current hard disk magnetic heads. Since, unlike with magnetic recording, light can be focused and steered from afar, it is possible to devise stationary optical heads for ODs. Previously, we have presented a method for doing so, ORRAS^TM (Optical Rapid Random Access Scanning). Here we shall describe ORRAS in more detail and report on new developments in this technology. ORRAS-II, an improved variant of the ORRAS technology, enables optical disk drives with worst case seek time of 3 ms, while using low precision components, facilitating practical high speed optical data access.