GB855388A - Improvements in or relating to apparatus for transmitting cinematographic films by television - Google Patents

Abstract

855,388. Television. FERNSEH G.m.b.H. March 18, 1957 [March 17, 1956], No. 8817/57. Class 40(3). Relates to apparatus for deriving television signals from a kinematograph film 8 in which the film is traversed through a gate 5 illuminated by a source 3, an image of the gate being projected upon the light-sensitive member of a television camera tube 11 by means of an optical system 7, 14. In accordance with the invention, the optical system is formed of two separate lenses or lens systems, the first, 7, being mechanically rigidly connected to the structural elements which determine the position of the film gate whilst the second, 14, is rigidly located with respect to the structural elements which determine the position of the camera tube. Furthermore, each lens is focused to infinity whereby all the rays emerging from any point of the film frame pass between the lenses along parallel paths. By this means, the slight variations in alignment between the components of the optical system, which are inevitably produced by the vibrations of the projector, have little effect upon the quality of the projected image, since the position of the image is no longer affected. In a preferred arrangement, a ratio between the focal lengths of the two lenses of 1:1À25 is used, the lens of shorter focal length incorporating the aperture stop and being attached to the film projector. The optical path between the two lenses is enclosed in order to exclude stray light. An arrangement for doing this where the support for lens 7 is hinged to permit access to the film gate is described, Fig. 2 (not shown).