GB524365A - Method and apparatus of projecting and of copying by projection lenticular colour orstereographic films - Google Patents

Abstract

524,365. Projection and projection-copying of lenticular films. LASSUS ST. GENIES, A. H. J. DE. Jan. 28, 1939, Nos. 3008 and 3009. Convention dates, Feb. 11, 1938 and Dec. 28, 1938. Drawings to Specification. [Classes 97 (i) and 98 (ii)] In the projection or projection-copying of lenticular colour or stereoscopic films, the angle subtended from the optical centre of each lenticular element, by the entrance pupil of the projection objective, is approximately equal to the sum of the angle subtended from the optical centre by the image of the exit pupil used in recording, which image is produced by the film in the focal plane of its lenticular elements, and of the angle subtended from the optical centre by the radiating surface of the light source. The angle subtended by the light source should be as small as possible, and the first-mentioned angle then approximates to the second. In the projection or projectioncopying of lenticular colour films of which the lenticular surface faces the projection objective, the angle subtended by the light source not being zero, the colour filter carried in the projection objective diaphragm has, in addition to the normal three bands, supplementary bands on either side of the normal bands, each of the same size as a band of the normal filter, and the bands being disposed in the same order as in the usual filter. In the projection of lenticular stereoscopic films on transparent screens comprising cylindrical optical elements, a light source is used, the radiating surface of which subtends a minimum angle in all directions at the optical centre of the lenticular elements, a narrow diaphragm is placed in the projection objective transversely of the lenticulations of the film, and the lenticulations are inclined to those of the screen. Specifications 470,801, 482,690, and 489,823 are referred to.