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. 05, 1986
Filed:
Apr. 16, 1984
Applicant:
Inventor:
Donald K Cohen, Tucson, AZ (US);
Assignee:
International Business Machines Corporation, Armonk, NY (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 45 ; 369 46 ; 250201 ;
Abstract
In an optical data storage disk device, focus of the recording and sensing beam is detected by sensing lateral shear (rotational orientation of a light interference pattern) of a beam reflected from the optical data storage disk. An exemplary shear detector includes a quadrant sensor having four quadrants for sensing the rotation of the reflected beam's interference pattern. Electrical analysis circuits illustrate evaluation of the sensed rotated interference pattern.