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. 10, 1990
Filed:
Dec. 05, 1989
Willem G Opheij, Eindhoven, NL;
Josephus J Braat, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
An optical scanning device which includes a radiation source, a mirror objective an a radiation-sensitive detection system, the mirror objective being a transparent body having a radiation window and a reflector symmetrical therewith on each of two opposed surfaces of such body. First diffraction elements are respectively arranged on the first and second radiation window and the second reflector, whereby radiation directed through the first window is focussed to a scanning spot on an information plane and radiation from such plane after a second passage through the mirror objective includes a number of diffracted beams directed on the radiation detection system. The diffracted beams enable detection of tracking errors and focussing errors of the scanning spot relative to tracks on the information plane.