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AUTOMATIC FOCUS WITH VARIABLE MAGNIFICATION

IP.com Disclosure Number: IPCOM000022936D
Original Publication Date: 1976-May-31
Included in the Prior Art Database: 2004-Mar-27

Publishing Venue

Xerox Disclosure Journal

Abstract

The system of the figure provides for automatically focus'- ing images of different magnifications onto a light sen'- sitive medium, First and second optical patterns of a wavelength to which the light sensitive medium 4 is not responsive are projected by first and second displaced mirrored grids 6 and 8 to the projection plane 10 of the images to be reproduced and then back to the grids 6 and The grids 6 and 8 have optically transparent portions therein such that when the returned optical patterns are not in focus, portions of the defocused optical patterns are transmitted through the transparent portions of the grids. The defocused portions of the optical patterns transmitted by the grids 6 and 8 are incident upon a roW- tating, disk~-spoked, optical modulator 11 consisting of a grid of alternate opaque and transparent pi-shaped seg- ments having twice the spatial frequency of the mirrors