TILT CORRECTION IN AN OPTICAL DISK SYSTEM

A servo system for the correction of disk tilt in optical disk data st orage is proposed, and its basic concepts are demonstrated by the use of a static system in which the disk does not spin. Because disk tilt produces primarily coma in the beam focused onto the disk, the system uses a variable coma generator to produce an equal and opposite amount of coma as that caused by the tilted disk. The magnitude and directio n of disk tilt are detected by the use of the light reflected from the front facet of the disk substrate. (C) 1996 Optical Society of Americ a