Steven M Furman

US Patent:

49493299, Aug 14, 1990

Filed:

Apr 27, 1988

Appl. No.:

7/300861

Inventors:

Steven R. Furman - Union NJ
James E. Kuder - Fanwood NJ

Assignee:

Hoechst Celanese Corp. - Somerville NJ

International Classification:

G11B 7013

US Classification:

369116

Abstract:

Provided is a process for the erasure of information recorded in an optical information medium. The erasure is effected by irradiating the medium with a laser beam, with the duty cycle, laser power and focus offset having been adjusted from that used during writing such that upon the irradiation complete and clean erasure of the information is effected. It is preferred that the focus offset and laser power are adjusted the minimal amount possible and that the duty cycle is the parameter of the three for which the greatest adjustment is made. Control and adjustment of the three parameters in accordance with the present invention permits one to realize more accurate, efficient and clean erasure, even bit-by-bit erasure if desired, than has heretofore been possible.