GB285013A - Means for interposing or displacing coloured screens in objectives specially applicable for cinematographic projection - Google Patents

Abstract

285,013. Soc. Franþaise de CinÚmatographie et de Photographie Films en Couleurs Keller-Dorian, (formerly Soc. du Film en Couleurs Keller-Dorian). Feb. 8, 1927, [Convention date]. Kinematograph apparatus; optical-projection apparatus. - In projectors for monochrome or multi-coloured images alternatively, and comprising a colour screen which produces an alteration in focus when brought into or thrown out of use, means is provided whereby in the act of moving the colour screen a substitution of parts is effected which renders refocusing unnecessary- The means may comprise, (1) a sliding frame, associated with the projection lens, and carrying a colour screen and a glass screen for alternative use (2) a rotatable turret carrying two projection lenses, one of which is provided with a colour screen, or (3) two fixed lenses, one provided with a colour screen, and a removable prism enabling the lenses to be used alternatively. As shown in Fig. 2, a frame 2. housed in slots through the lens mount, carries a sliding carrier 3 which is fitted with a colour screen 4, and with a, glass screen 5 serving to maintain the focus of the image when the screen 4 is not in use. Fig. 4 shows fixed lenses 1<1>, 1<11>, the lens 1<11> being provided with a colour screen. a. collimating lens 6 as close as possible to the film, and a prism 7 which may be brought into position in any desired manner to deflect the projection beam. The necessary movements may be effected by hand or automatically, by electromagnetic means, under the control of perforations in the, film. A luminosity compensating screen may be provided in conjunction with the lens not provided with a colour screen. Specification 247,168 is referred to.