Stereoscopic projection

571,944. Stereoscopic kinematography. BRITISH THOMSON-HOUSTON CO., Ltd., and CASTELLAIN, A. P. June 1, 1943, No. 8764. [Class 97 (i)] A stereoscopic kinematograph system, in which right- and left-eye images are projected in the form of interlaced strips on to the rear of a screen and are viewed through a vertical line grating at the front, employs a film bearing either the interlaced images, Fig. 3, or pairs of separate right- and left-eye images, Fig. 2, the vertical dimensions of the images extending transversely to the film. The film is moved at uniform speed before a transversely scanning light spot which, in conjunction with a photoelectric cell and amplifier, is used to control a cathode-ray tube to reconstitute the images as interlaced images on the screen of the tube, which reconstituted images are projected on to the projection screen. In the case of the image arrangement shown in Fig. 2, each scan of the light spot covers one line of each of the left- and right-eye images, and since these lines are interlaced on the screen of the projection cathode-ray tube the number of scans given to each image will be half the total number of lines in the interlaced image. The projection tube screen may be one which modulates a projected light beam forming the image on the projection screen. The scanning light spot may be produced by a cathode-ray tube, the scan of the beam of which is synchronized with that of the projection cathode-ray tube ; and the latter may be controlled by circuits associated with the motor which gives the film its uniform motion. Coloured images may be projected by the use of a colour disc interposed in the image beam and rotated by a motor interlocked with the motor driving the film. The film may be produced as described in Specification 571,945. Specification 321,935, [Class 98 (i)], also is referred to.