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:
Mar. 08, 1977
Filed:
Sep. 04, 1975
Applicant:
Inventors:
Carel Arthur Simons, Eindhoven, NL;
Hendrik' T Lam, Eindhoven, NL;
Assignee:
U.S. Philips Corporation, New York, NY (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
358127 ; 1791 / ; 358128 ;
Abstract
An apparatus is described for reading a radiation-reflecting record carrier on which information is stored in an optically readable track-shaped phase structure. The apparatus inter alia includes a radiation source, an objective system and a radiation-sensitive detection system. By a suitable arrangement and a suitable choice of the power of a cylindrical lens, which lens in conjunction with a four-quadrant detector supplies a focussing signal, it is possible to detect centering-errors with the aid of only two additional detectors in the plane of the four-quadrant detector.