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. 26, 1991
Filed:
Oct. 20, 1988
Hitoshi Yanagihara, Kamakura, JP;
Nobuhiro Tokushuku, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The present invention relates to an optical information medium for recording and reproducing information optically. Particularly, it is concerned with a so-called sample servo type optical information medium wherein an optical head traces over the center line of an imaginary track on the basis of information obtained from at least a pair of wobble pits disposed on both sides of the said imaginary track center line. A continuous groove is formed between the paired wobble pits along the imaginary track center line in a certain area of the optical information medium so that the deviation of each wobble pit from the imaginary track center line can be easily grasped and the conditions of the wobble pits being formed can be estimated. The quality of the medium being manufactured can be easily judged by the presence of such continuous groove.