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:
Aug. 03, 1993
Filed:
Sep. 11, 1991
James J Dente, Tucson, AZ (US);
Alan A Fennema, Tucson, AZ (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
The focus acquire system on optical disk recorder as well as other optical systems, signal processes a focus error signal FES to produce a modified FES which has a peak amplitude occurring closer to a desired focus position than the occurrence of peak amplitude of the FES. The modified FES also is signal processed to sharpen or slim the peak portion such that increasing the amplitude of the modified FES reaches an amplitude detection threshold closer to the true peak of the modified FES, and hence closer to the desired focus position than if the amplitude detection threshold were used on the FES. In a preferred form of the invention, FES is differentiated to produce a differentiated FES, then the differentiated FES is subtracted from FES to produce the modified FES.