GB428043A - Improvements in or relating to optical projecting apparatus - Google Patents

Abstract

428,043. Optical-projection apparatus ; colour and stereoscopic kinematography and photography. BRICON TRUST, Ltd., 50, Pall Mall, London, and EIMERT, H., (trading as ECKELT & CO. APPARATEBAU), 23, Genthinerstrasse, Berlin. Aug. 4, 1933, Nos. 22012, 22013, and 22014. Void [Abridged as open to inspection under Sect. 91 of the Acts, Feb. 20, 1934]. [Classes 97 (i) and 98 (ii)] In optical-projection apparatus, the light is reflected by the image without scattering and is projected by optical means on to a screen. As shown in Fig. 1, light from the source 15 reflected by the mirror 16 is reflected by the image 20 on to a prism 25 having a semi-transparent reflecting cemented surface 26 situated at the focus 18 of the rays reflected by the image 20. The rays reflected by the surface 26 are projected on to a screen 30 by an objective 28. The surface of the prism facing the source of light 15 may be spherical. A planoconvex lens inclined at 45‹ to the plane of the image and in which the plane side, which faces the image, is semi-transparent, may replace the prism. A glass plate having the side facing the image semitransparent may be employed in conjunction with a convex lens between the plate and the light source and having its focus behind the image. The reflecting surface may be so placed that the focus 18 falls in the objective 28. In a further modification the reflecting surface may reflect the light on to the image, which is parallel to the original light rays, and two lens systems are arranged on opposite sides of the reflecting surface. Fig. 7 shows a stereoscopic camera with two lenses 44, 45 producing images on both sides of the film 48 by means of the two mirrors 50, 51. A stereoscopic projector is constructed similarly to the camera with the addition of two concave mirrors and light sources. Fig. 9 shows a colour camera comprising an objective 60, a light-dividing prism system 62, 63, mirrors 66, 67, 68, 69, 70 reflecting the light on to opposite sides of the opaque film 74, and colour filters 76, 77. The projection apparatus is similar with the addition of two concave mirrors and sources of light. The colours on the film are reflecting.