GB508497A - Improvements in and relating to diascopic projection apparatus - Google Patents

Abstract

508,497. Optical-projection apparatus. ANCIENS ETABLISSEMENTS BARBIER, BENARD, & TURENNE, and MESTRE, L. N. Dec. 31, 1937,No. 36240. [Class 97 (i)] A diascope includes at least two objectives corresponding to different magnifications, at least one of which is associated with a coaxial condenser, the objectives and condensers being carried on supports rotatable integral with each other so that one optical system may be substituted for another, As shown, the condensers 44 ... 46 are carried on a plate 43'supported by a rotatable shaft 39' connected by a coupling 41 to a shaft 39<11> bearing the corresponding objectives 54, 55, 56, the shafts being rotated by gear-wheels 60, 61 driven by a hand wheel 58. A spring-pressed pin 49 engaging a recess 48 in the plate 43 holds it in position. The object carrier comprises a plate 20 rotatably supported in a sleeve 11 vertically adjustable by a screw 15 for focusing. The disc 20 has four circular apertures bearing rotatable discs 23, 23<1> carrying the objects to be projected. As shown, the disc 23 has guides 27, 28 along which the negative or positive 29 may slide during projection. The disc 23<1> carries film feeding and receiving rollers 31, 32, and a spring-pressed plate 35 to hold the film. Spring pressed plungers hold the plate 20 in position. A diaphragm 70 may be provided, and the adjustable mirror 63 may be placed before the objective. A water tank 5 is placed before the lamp 3 and fixed condensers 4.