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:
Oct. 05, 1982
Filed:
Apr. 29, 1980
Applicant:
Inventors:
Toshio Sugiyama, Toyokawa, JP;
Takeshi Maeda, Kokubunji, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01J / ;
U.S. Cl.
CPC ...
250201 ; 369 45 ;
Abstract
In the case where the focus control or the tracking control of a light beam is performed by using the wobbling method in an optical information reproducing apparatus, the envelope of the reproduced signal obtained from the light reflected from the recording medium in a non-modulated state is diode-detected and the detected output is used as a focus control signal while the envelope of the reproduced signal obtained from the recording medium in a modulated state is diode-detected so as to be used as a tracking control signal.