The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 07, 1995
Filed:
Oct. 15, 1993
Applicant:
Inventor:
Matthias C Krantz, San Jose, CA (US);
Assignee:
International Business Machines Corporation, Armonk, NY (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 4441 ; 369 4412 ; 369 4432 ; 369112 ; 369120 ;
Abstract
An optical data storage system comprises a laser for generating a beam of light, an optical data storage media, transmission optics for directing the beam of light to the optical medium, reception optics for receiving a reflected beam from the medium, and circuits for generating a data, tracking error and focus error signals. The reception optics includes a segmented detector. The signals from at least two of these segments are differentially adjusted such that the resulting output focus error signal is approximately independent of nonfocus wavefront aberrations.