GB733780A - Improvements in or relating to optical systems for splitting a single light beam into two or more corresponding beams or combining units one, two or more light beams - Google Patents

Abstract

733,780. Optical systems. TECHNICOLOR MOTION PICTURE CORPORATION. Nov. 26, 1951 [March 30, 1951], No. 27698/51. Class 97 (1). An optical system comprises at least two curved reflectors and a corrected plate together with a beam-splitting or combining device, the reflectors and the corrector plate being so shaped and arranged as to be symmetrical about a common optical axis, the reflectors being so disposed along the axis facing each other that each of two objects constituted by substantially parallel picture surfaces situated on the axis and on either side of the curved reflector system has a real conjugate image of itself produced in superposition on the other object, and a third object situated at a position such that it does not obstruct the common light beam producing said conjugate images, the beam splitting or combining device being so placed in relation to the axis and to the third object that it intercepts the common light beam and a real conjugate image of the third object is formed upon one of the first-mentioned objects, or a real conjugate image of one of the first-mentioned objects is formed on the third object. As shown in Fig. 1, the optical system comprises co-axial reflectors RIa and RIIs, a corrector plate Ca and a beam-splitter LIa arranged so that real images of picture surfaces P2a and P3a are projected on to a screen P1 or images of an object P1 are formed on surfaces P2a, P3a. If desired, the beam splitter Lla may be arranged between and parallel to both P2a and P3a. In the form shown in Fig. 3, a colour television optical system comprises cathode-ray tubes P2b, P3b and P4, the light beams from which pass through green, red and blue filters Fg, Fr and Fb, respectively. The green and blue beams are combined at L21 and the resulting beam is combined at L1 with the red beam from tube P3b so that the images on the cathode-ray tubes are projected into superposition on a screen S1. An arrangement is also described in which crossed transparent reflectors act as the beam splitter or combiner (Fig. 5, not shown). Specification 733,845 is referred to.