GB576421A - Improvements in or relating to stereoscopic apparatus in relation to cinematograph reproduction - Google Patents

Abstract

576,421. Stereoscopic viewing devices. FRANKLIN, A. P. Aug. 31, 1943, Nos. 14191/43, 17180/43, 17383/43, 18472/43 and 3592/44. [Class 97 (i)] An apparatus for viewing stereoscopic pictures at a distance comprises a viewing device on an adjustable support, the support allowing movement of the viewing device within limits, but maintaining the device so that a line joining the centres of the eyepieces is always in a plane passing through the centres of the pair of pictures and positively restraining movement out of that plane. As shown applied to a cinema theatre, the device has a body 2 flared at one end and with a central partition 6 divided at the viewing end into two flaps 60 adjustable to suit the distance apart of the viewer's eyes, the flared end of the body having two adjustable shutters 14 to cut out extraneous light. Two interchangeable and laterally adjustable prisms 10, which may be rotatably mounted, are fitted on either side of the partition and the whole device is mounted on an adjustable support which, while preventing rotation out of a plane passing through the centres of the pictures of a line joining the centres of the prisms, allows the device to be comfortably, adjusted before the eyes. The viewing end may have an adjustable tube for each eye instead of the flaps 60 and one prism only may be used (Fig. 7, not shown). In a modification, Fig. 1 of Provisional Specification 18472/43 (not shown), the flared end of the body is replaced by two adjustable conical tubes, in the narrow end of which are mounted the prisms. Figs. 4 and 5 of Provisional Specification 3592/44 (not shown), illustrate a method of supporting the device from the back of the seat in front of the viewer. Lenses of small magnification may be incorporated in the device and the prisms may be replaced by colour filters or filters for polarised light. The prisms may be removed and the device adjusted for viewing without stereoscopic effect. The only adjustment required by the viewer is that for the distance apart of the eyes, all the other adjustments being pre-set. The device may be mounted on a portable stand for viewing stereoscopic television pictures.