Optical-electronic focussing device for photographic reproduction - has reflected marker in image beam with photo-electric transformers controlling focus motor

摘要

An optical electronic focussing device for photographic reproduction devices, has at least one reflected marker directed into the image beam of the system. It uses the lens of the system in an auto-collimator manner with variable shortening or lengthening of the autocollimator beam path on a test panel. The image formed by the projecting edges of the marker is fed to a pair of photoelectric transformers which control the operation of a focussing motor in order to produce a symmetrical image.