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. 29, 1981
Filed:
Dec. 20, 1979
Applicant:
Inventors:
Toshimitsu Miyauchi, Hachiouji, JP;
Yoshito Tsunoda, Mitaka, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 48 ; 371 10 ;
Abstract
In apparatus wherein a predetermined information signal is recorded on an optical disk by the use of a light beam; an information recording apparatus characterized by provision of a light detector for detecting reflected light caused by the reflection of the light beam by the optical disk, and a checking circuit for detecting the duration for which a maximum peak value of the output from the light detector exists, the recorded state of information on the optical disk being detected on the basis of the output from the detector by the checking circuit.