Method and apparatus for optically sensing accurate clock patterns

Abstract

A disk drive system is described for forming and reading precise optically detectable patterns on rotating members of a disk and spindle assembly used in data storage system. In particular the invention describes a magnetic disk drive employing a laser system to form and sense optical clock patterns placed on the rotating members of the disk drive. These optically detectable patterns are used to create an accurate clock track. The clock may be used to create multiple accurate magnetic patterns on one or more disks attached to a disk and spindle assembly in a magnetic data storage system. By successively changing the radius at which the magnetic patterns are created it is then possible to create multiple magnetic patterns at successive radii with all such magnetic patterns having a precise geometric relationship to each other. Alternatively, the accurate clock pattern may stand alone as an encoder. Additionally, the laser system may also be used to form textured surfaces on a disk to control the flying characteristics of a magnetic head slider assembly. These textured surfaces may also serve as a resting area for the magnetic head slider assembly when the disk is not spinning.