GB357660A - Improvements in optical systems for cameras for photography or kinematography particularly in colour - Google Patents

Abstract

357,660. Optical systems. HILLMAN, A. G., GILL, B. T., and GERRARD WIRE TYING MACHINES CO., Ltd., Victoria House, Vernon Place, Southampton Row, London. July 4, 1930, No. 20330. [Class 97 (i).] Three-colour and like systems reflector systems.- A light-dividing system to be placed behind the lens of a camera for obtaining multiple images in colour photography comprises a pair of reflecting surfaces disposed in intersecting planes and adapted to divide the beam transmitted by the objective into four sections, two of which, passing unobstructed by the system, are on the optical axis and may combine to form one direct image or be separated to form a direct and a reflected image. The system consists of a disc-shaped reflector 1 mounted within a ring-shaped reflector 2. Light reflected from the mirrors 1, 2 form images in the planes 4, 6 respectively after passing through a red filter 3 and a blue filter 5. Light passes unobstructed by the system through the zone 7, Fig. 5, between the reflectors and also through the marginal zone 8, and, in the arrangement shown, the two unobstructed portions combine to form an image in the plane 10 after passing through a green filter 11. If it is desired to produce a fourth colourcomponent image, the rays passing through the zone 7 are diverted by an additional ring-shaped reflector placed behind the system. The reflectors 1, 2 are slightly elliptical in outline and the width of the reflector 2 progressively increases from a minimum at K<1> to a maximum at L<1>. The disc reflector 1 is offset from the true optical axis in the direction of the focal plane 4, the ring 2 being also offset in the same direction, and the disc 1 being further offset towards the rear of the ring. The disc 1 may be provided with a central aperture 14, the light passing through this aperture being deflected by a small mirror and utilized for focusing purposes.