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:
Dec. 31, 1991
Filed:
Aug. 24, 1988
Shigenori Yanagi, Kawasaki, JP;
Masateru Sasaki, Yokohama, JP;
Akira Minami, Yokohama, JP;
Toshitaka Iwamoto, Kawasaki, JP;
Shigeyoshi Tanaka, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
An optical disk access system capable of varying the focus position of a beam spot illuminating the optical disk. The focus position of the beam spot is varied in accordance with a mode of operation of the optical disk system. The various focus positions are automatically selected by the optical disk access system by intentionally vibrating the beam spot in a radial direction of the optical disk and detecting the amount of light reflected from the optical disk while varying a signal that changes the focus position of the beam spot. The optical disk system automatically selects a value of the signal determining the focus position of the beam spot that corresponds to maximum values derived from the light reflected from the optical disk.