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:
Jan. 07, 1986
Filed:
Jul. 22, 1982
Applicant:
Inventors:
Takeshi Maeda, Kokubunji, JP;
Kazuo Shigematsu, Saitama, JP;
Masahiro Takasago, Odawara, JP;
Yasumitsu Mizoguchi, Odawara, JP;
Zenji Tsutsumi, Kokubunji, JP;
Yoshito Tsunoda, Mitaka, JP;
Motoo Uno, Kokubunji, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 44 ; 369 45 ; 250201 ;
Abstract
A method of detecting a light spot control signal is disclosed in which, when information is reproduced from an optical disk for optically recording information, a signal level obtained at a high-reflectivity portion of the optical disk is taken out of a signal reproduced from the optical disk, and is used as a control signal, which controls a light spot so that it tracks information stored in the optical disk.