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:
Jul. 20, 1999
Filed:
Mar. 06, 1997
Applicant:
Inventor:
Josephus J Braat, Eindhoven, NL;
Assignee:
U.S. Philips Corporation, New York, NY (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 58 ; 369112 ; 369118 ;
Abstract
An optical scanning device can scan two types of record carriers each having a transparent layer with a different thickness, in which a focused radiation beam scans an information layer of the record carrier through the transparent layer. When scanning a first type of record carrier the best focus of the radiation beam is positioned on the information layer and when scanning a second type of record carrier the paraxial focus of the radiation beam is positioned on the information layer. The lens system focusing the radiation beam comprises an opaque ring between a transparent central area and a transparent annular area.