OPTICAL IMAGING SYSTEM 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

摘要

15.1.80 1 PHN 9487ABSTRACT:Optical imaging system provided with an opto-electronicdetection system for determining a deviation betweenthe image plane of the imaging system and a secondplane on which an image is to be formed.An optical imaging system is described whichis provided with an opto-electronic detection systemfor determining a deviation between the image planeof the imaging system and a second plane on which animage is to be formed by the imaging system. After afirst reflection on the second plane an auxiliarybeam which is obliquely incident on said plane isreflected along itself and mirror-inverted, is sub-sequently reflected a second time on the second plane,and is finally incident on two detectors. The dif-ference signal of the detectors, which is a measureof the said deviation, is independent of a tiltedposition of the second plane and of local differencesin reflection in said plane.