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:
Oct. 26, 1982
Filed:
Jun. 11, 1980
Stefan Wittekoek, Eindhoven, NL;
Theodorus A Fahner, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
An optical imaging system is described which is provided with an opto-electronic detection system for determining a deviation between the image plane of the imaging system and a second plane on which an image is to be formed by the imaging system. After a first reflection on the second plane an auxiliary beam which is obliquely incident on said plane is reflected along itself and mirror-inverted, is subsequently reflected a second time on the second plane, and is finally incident on two detectors. The difference signal of the detectors, which is a measure of the deviation, is unaffected by tilting of the second plane and by local variations in reflectivity of in said plane.