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:
Nov. 11, 1980
Filed:
Jul. 17, 1978
Gijsbertus Bouwhuis, Eindhoven, NL;
Teunis J Hazerdonk, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
An opto-electronic focussing-error detection arrangement is described for the detection of a deviation between a radiation reflecting surface and the plane of focussing of an objective system. In the path of the beam which is reflected by the surface a beam-splitting element is disposed and behind said element two radiation-sensitive detectors are arranged which are each associated with one of the subbeams formed by the beam-splitting element. The detectors are grating-shaped detectors and are effectively divided into two detector sections by selection devices, the bounding line being adjustable. A focussing error signal is obtained which is highly independent of a positional error of the radiation-sensitive detection system relative to the beam axis.