Optical servo for magnetic disks

摘要

The surface of a magnetic recording disk is encoded with optically sensed indicia, which is employed to control track following of the read/write slider head along a track on a magnetic recording medium such as a disk. The means of reading the medium is to employ a laser carried by the slider which cooperates with the medium as a reflector which affects the lasing function or modulates the operating characteristics of the laser diode. The retro-reflected light changes the operating voltage of the diode. Preferably, the disk is coated with a multiple layer optical recording medium deposited upon the upper surface of the magnetic recording medium.