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:
Aug. 06, 1985
Filed:
Aug. 26, 1982
Applicant:
Inventor:
Antonius A van Alem, Eindhoven, NL;
Assignee:
U.S. Philips Corporation, New York, NY (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
G01J / ;
U.S. Cl.
CPC ...
250201 ; 369 45 ;
Abstract
An optical focusing-error detection device comprises a beam splitter arranged in the path of a radiation beam originating from a plane on which is to be focused, and a radiation-sensitive detection system comprising a plurality of detectors separated by narrow strips, a first strip being associated with a first one and a second strip with the second one of two subbeams formed by the beam splitter. By arranging the two separating strips at an acute angle relative to each other it is possible to ensure that the centers of the radiation spots formed in the detector plane by the subbeams are disposed on the separating strips when focusing is correct.