GB612376A - Improvements in cabinets for optical projection apparatus - Google Patents

Abstract

612,376. Television receivers. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. May 23, 1946, No. 15607. Convention date, May 23, 1945. [Class 40 (iii)] [Also in Group XX] A cabinet for optical projection apparatus, e.g. television or cinematograph apparatus, has a receiving screen hinged thereto to serve as a closure member for the cabinet and a reflector coupled to the screen and slidably connected in the cabinet so that upon movement of the screen from viewing to closing position the reflector moves from its operative position to a position within the cabinet. As shown in Fig. 1, a cabinet 10 has a viewing screen 34 carried by a frame 32 supported at the top edge of the cabinet by means of hinges 36, a reflector 42, carried by a frame 44 and serving to reflect towards screen 34 optical images produced by the cathode-ray tube 18 and directed on to the reflector 42 by the spherical mirror 20 and aspherical correcting plate 16, being hinged at 46 to the frame 32 and slidably connected with grooves 50 by means of cam followers 48 to permit movement of the reflector from a position within the cabinet to its operative position when the viewing screen 34: is moved from its closed position to its viewing position. The screen is maintained in its viewing position by means of latch members 38 and 40. Masking members 54, Fig. 2, hinged at 56 to the frame 32 are arranged to prevent direct viewing of the reflector 42 when the screen 34 is in viewing position and, when the screen is in the closed position, to provide a protective covering for the screen. Alternatively, the masking members may comprise triangular plates hinged to the frame 32 and adapted to lie within the cabinet when the screen is in the non-viewing position, the members 54, if used, serving only as protective panels for the screen (Fig. 4, not shown). To obtain precise alignment of the reflector with respect to the viewing screen, an arrangement including. a spring-urged bell-crank and an adjusting screw is provided at the top of one or both slots 50 to co-operate with the cam followers 48 (Fig. 6, not shown).