Abstract

When used for projecting or editing motion picture film the optical rectification apparatus produces a stationary image of a frame of a moving film and a succession of superimposed stationary images from successive frames of the moving film. The apparatus employs an optically transmissive hollow cylindrical prism having a cylindrical external surface and an internal surface consisting of a number of facets. Light from the moving film is passed outwardly through the wall of the rotating prism and through a stationary plano-concave cylindrical lens positioned with its concave surface adjacent the external surface of the prism, but spaced slightly from it. The prism is connected to the same shaft as the film sprocket wheel resulting in an isotransport system in which the prism rotates in synchronism with movement of the film to deviate the light through an angle sufficient at each instant to compensate for the angular deviation of the light caused by movement of the film.