GB619843A - Improvements in and relating to optical projection equipment - Google Patents

Abstract

619,843. Optical projection apparatus. KINGSTON, A. W. Dec. 31, 1946, No. 38176. [Class 97 (i)] Portable apparatus for still or moving pictures has alternative optical systems for projection, respectively, on to a self-contained translucent screen or through an aperture in the casing on to an external screen. In the kinematograph projector shown, the film is fed horizontally through the gate 6 between spools, one of which is shown at 19. It is illuminated by a lamp 5 with condenser 48, reflecting prism 8 and shutter 10. A lens turret consists of plates 35, 36 mounted on a spindle 38 for rotation in a block 39. One tube 41 secured to the plate 35 carries a short throw projection lens for projection on to the screen 14, carried on arms 15 from the lid 2, of the casing, and which may be folded to the position shown in dotted lines for transport. Part 18 of the lid is hinged to allow the arms 15 to be erected. Clips 17 secure the arms in their open or closed positions. The light beam is reflected from mirrors 11 and 12 carried by the lid and passes through a prism 44, carried in the tube 41 to turn the projected picture through 90 degrees. For projection through the aperture 34 on to an external screen a long throw projection lens in the tube 42 is brought into use. The light beam from this passes through right-angled prisms 46, 47 carried by the plate 36 and arranged Porro-fashion, but with corresponding edges of their hypoteneuse faces at 135 degrees to give picture erection.