GB629472A - Improvements in and relating to kinematographic projection with continuously-moving film - Google Patents

Abstract

629,472. Kinematograph projection apparatus. SCOPHONY, Ltd., WIKKENHAUSER, G., and ADAMS, A. E. Nov. 5, 1946, No. 32897. Addition to 589,971. [Class 97, (i)] The apparatus disclosed in the parent Specification is modified by providing several lamps and means for causing these lamps to flash in succession as the illuminating means. Thus, in the kinematograph projector shown, the continuously moving film 13 is successively illuminated by light which passes through a condenser 12 and is alternately emitted by lamps 1 and 2 which are connected to an electric supply 5 through a rotating switch contact 7. The speeds of rotation of switch contact 7 and of the film movement are so related that two flashes occur during the passage of each film frame across the gate (not shown). The film movement during the interval between successive flashes is compensated by an image displacer 16 which comprises a prism 19 and a plane mirror 18 which are rotated about an axis 17 so that the images of the picture in each film frame formed by the two flashes are projected by lens 14 to take up the same position on the screen 15. Instead of the condenser 12, a concave mirror associated with each lamp may be used. To ensure good definition, there may be provided a structure in the form of a disc having a radial slot of suitable width, the disc being rotated in synchronism with the film advancing means and with the switch contact 7 so that two successive flashes of light illuminate each film frame. When it is desired to have a number of flashes per frame which is greater than two, three or more lamps may be provided. Also, two lamps may flash alternately, three of the resulting flashes being used to illuminate each film frame. Image displacing devices of the kind described in Specification 629,179 and in the parent Specification may be used.