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:
Feb. 14, 1989
Filed:
Oct. 08, 1986
Karl J Stahl, Boulder, CO (US);
Albin K Johnson, Boulder, CO (US);
Brad R Reddersen, Broomfield, CO (US);
Alexander M Muckle, Boulder, CO (US);
Storage Technology Partners II, Louisville, CO (US);
Abstract
An optical disk servo system includes a coarse access and tracking system for optical head control and a fine access and tracking system for read/write beam control. Enlarged servo tracks are pre-recorded on the optical disk between bands of data track locations. The coarse system illuminates a relatively large area of the disk surface encompassing at least one of the servo tracks and detects light from the enlarged illuminated area. Suitable means including a photo-detector array identifies and controls the optical head position by means of the light returned from the illuminated servo track. Such photo-detection means are insensitive to light reflected from the data tracks. The fine access and tracking system uses a conventional, three spot tracking and read system, two spots for data track following and one spot for data track reading. The fine access and tracking system controls a galvanometer mirror or other suitable means steering the read spot beams. Data writing is accomplished by fine tracking a previously recorded data track and maintaining the write beam a constant distance therefrom.