GB257549A - Improvements in optical devices for photographic, kinematographic and other purposes - Google Patents

Abstract

257,549. Romer, J. F. May 28, 1926. Prints.-Optical systems for producing simultaneously two laterally reversed images of an object in the same plane consists of a composite prism having total and semi-reflecting surfaces. The rays from an object 0 pass normally through the surface X<1> of the prism P<1> on to the semi-reflecting surface S' common to the prisms P', P<2>, by which they are divided. One portion passes directly through the surface S<1> to the lens L<2> and the other portion of the rays is reflected to the totally reflecting surface R' from which it passes through the surface S' to the inclined surface R<2> of the prism P<2> by which it is reflected to the lens L<1>. Both incident and emergent beams pass normally through the external surfaces of the composite prism, and form images M<1>, M<2> laterally reversed with respect to each other, in the same plane. Modifications of the forms of the prisms are described, in one of which the reflected rays are again reflected at a semi-reflecting surface, and in other of which both divisions of the rays are further reflected before passing out of the composite prism. The. same system may be used to combine by optical projection two laterally reversed images into one composite image. Colour filters may also be used, when employing the system for colour photography.