System for indexing and projecting microfilm for scanning

Claim 1

In a system for projecting a microfilm carrying stored or recorded information and index symbols therefor, comprising a projector including a viewing screen having a mat viewing area, optical means for projecting images from the microfilm onto the viewing area of the screen, and means for passing the film through the projector reLative to the optical means, said optical means including an optical compensating device rotatable in synchronism with the linear movement of the film, the improvement wherein the microfilm includes longitudinal side-by-side sections respectively provided with cue index symbols and oppositely arranged text of the recorded information identifiable by such symbols, the text of the recorded information extending continuously along its side section of the microfilm and the cue indexing symbols being located at spaced intervals along the symbol side of the film respectively opposite appropriate portions of the text, and wherein the disposition of the compensating device relative to the sections of the microfilm is such that it will hold the images of the cue indexing symbols stationary by refraction on a predetermined area of the screen while images of the text on the microfilm are moving at high speed across the screen with uninterrupted movement of the film relative to the optical means until a desired cue index symbol is displayed on the symbol side of the screen and the film is stopped to permit reading of the text on the screen opposite the desired index symbol.