GB628756A - Improvements relating to cinematograph continuous feed projectors - Google Patents

Abstract

628,756. Kinematograph continuous-feed projectors. KUDAR, J. Nov. 25, 1946, No. 34944. [Class 97 (i)] In a projector wherein compensation for the continuous movement of the film is effected by a rotary polygonal prism, and the film is guided along a curved path by a rotary beam deflector element having a series of concave-cylindrical or plane surfaces, each of which corresponds to one film frame, the prism and element are rotated in unison about parallel axes and each film frame as it moves along the said path through the illuminating beam coincides with and is located within an air lens which forms one of a series of cylindrical convex air lenses rotating about the axis of the beam deflector element and formed by the faces of the deflector element and a cylindrical concave face of a stationary field lens located between the compensating prism and the beam deflector element. As shown in Fig. 1, the rotating beam deflector element 2 has cylindrically concave faces 2a and continuously moves the film 3 by engagement of sprocket teeth 5 on the element with the film perforations. Close to the film is placed a field lens 6 having a cylindrical concave face 7 and a face 8 which is preferably plane; lens 6 is mounted in a frame 9, carrying film contacting rollers 10, 11 and movable along the projection axis. Between lens 6 and the projection lens 15 is the usual compensating prism 1 which rotates about an axis parallel to the axis of the 'cylindrical face 7 of the field lens and the axis of rotation of the element 2. Each film frame thus lies within an air lens as it moves in a curved path through the light beam, the source of illumination being provided either within the hollow element 2 or outside said element in which case a suitable light reflector is employed to deflect the light onto the film. Specification 620,580 is referred to.