GB552582A - Improvements in television - Google Patents

Abstract

552,582. Stereoscopic apparatus. BAIRD, J. L. July 11, 1941, Nos. 8774 and 12862. [Class 97 (i)] [Also in Group XL] A stereoscopic television transmitter, Fig. 1, comprises a cathode-ray tube 1 producing a scanning spot on a single field area of its screen 2, a single lens 9 for focusing the light on to the required spot of the scene or object 3, a multiple mirror or like device 10, 11, 12, 13 close to the lens on the side remote from the cathode-ray tube for dividing the light into two beams scanning the objects from points virtually spaced apart to correspond to right and left eye views, a shutter 16 arranged to rotate between the mirrors and the object to obscure the respective beams alternately, and means such as a photo-electric device 14 for converting the light into electrical impulses and transmitting the impulses by wire or wireless. If colour reproduction is desired, a rotating colour screen 4 is provided between the cathode-ray tube 1 and the single lens 9. In a receiver, Fig. 2, of generally similar arrangement, the object is observed by a person 31 through a field lens 27 focusing a pair of slots in a rotating shutter 28 on the eyes of the observer. Several pairs of slots may be provided for several observers 31, 31<SP>1</SP>, 3111. In a modified transmitter, Fig. 4, half the lens 46 between the cathode-ray tube 41 and the multiple-mirror device 50, 51, 52, 53 is covered by a fixed screen 48 of one colour and the other half by another fixed screen 49 of another colour and a two-colour rotating screen 42 cooperates with the fixed colour screens to produce the alternate shuttering of the two stereoscopic beams. The shutter devices of Figs. 1, 2 and 4 may be replaced by shutter devices depending on the use of light polarizers. The transmitters, Fig. 1 and 4 may be made to operate with the light beams in reverse direction, that is to say, the object may be flood lighted and the light from the object proceed to a photo-electric mosaic or electron-camera type of transmitter. The Specification also describes the use of receivers in which the image appears on a screen and is viewed by means of coloured or polarized glasses in front of the observer's eyes. In applying the invention to two-way working, the mirrors for scanning the face of the transmitting person are arranged one either side of the field lens by which he sees the received image, and rotating colour screens are used to screen the transmitting cells from the received image.