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:
Nov. 01, 1994
Filed:
Jan. 06, 1994
Applicant:
Inventor:
Hidekazu Tominaga, Kawasaki, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 4432 ; 369 4425 ;
Abstract
An apparatus for effecting recording and/or reproduction of information by scanning an optical recording medium with a condensed light beam includes a detecting device for detecting a focusing error signal of the light beam, a focusing servo device for correcting a focusing state of the light beam on the basis of the focusing error signal, and a device for detecting abnormality of the focusing servo.