System for creating, reading and writing on rotatable information storage media, a method for writing closely spaced information tracks

摘要

A method for writing information on a laser writable recording blank with reference tracks utilizes a split laser beam. A first of these beams is used for writing while the second is directed to a mirror or similar device which causes the second beam to move across a track edge in an oscillatory manner. The laser light reflected in this process is converted to an electrical signal which is analyzed to determine very precisely the distance between the track edge and the point of impingement of the first beam on the disk. Power in this first beam is then controlled so as to write information on the disk. The precise control allows a plurality of information tracks to be written between adjacent reference track portions.