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. 13, 1987
Filed:
Sep. 05, 1985
Applicant:
Inventors:
Assignee:
Ricoh Company, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01J / ; G11B / ;
U.S. Cl.
CPC ...
250201 ; 250204 ; 369 45 ;
Abstract
Less than half of a laser beam reflected from an optical information storage medium through an objective lens is detected by a detector having two light detecting areas. The sum of output signals from the light detecting areas of the detector is employed to detect when the objective lenas enters a focusing range. The difference between the output signals is employed to detect when the laser beam is focused on the optical information storage medium.