GB448238A - Improvements in scanning devices for television apparatus - Google Patents

Abstract

448,238. Television. TRAUB, E., 34, Dartmouth Road, Cricklewood, London. Dec. 3, 1934, No. 34655. [Class 40 (iii)] A low-speed or framing scanner 14 is associated with a high-speed or line scanner 9 in which each in turn of a plurality of stationary reflecting surfaces 12 receives light from, and reflects it back to, each of a plurality of reflecting or refracting surfaces 11 on the rotating- member 9. The reflecting faces of the polygonal drum 9 are lenticular and equally inclined to the axis. The reflecting faces 15 of the polygonal drum 14 are wider in the direction of rotation than the incident light. According to modifications : the rotating-drum 9 has two superimposed surfaces of cylindrical lenses, which respectively receive the light before, and after, its reflection at stationary internally reflecting prisms, which return the light along a path parallel to its original path, and the low-speed drum has a lens in each face, and a refracting or reflecting member within the drum diverts the light, Figs. 2 and 3 (not shown) ; the low-speed scanner comprises a ring of inwardly facing stationary mirrors, which surround a double-sided rotating member, and each of which receives light from, and reflects it back to, the rotating mirror, as described in Specification 419,120, Fig. 4 (not shown); the low-speed scanner is similar to the high-speed scanner described in connection with Fig. 1, and in Specification 425,552; an additional stationary reflector reflects the light back to the rotating-drum after its second reflection for a third reflection, after which the light is again reflected to the original stationary reflector and a fourth time to the rotating-drum, as described in Specification 440,055, Fig. 5 (not shown). For interlaced scanning, a refracting-prism is placed over, Fig. 6 (not shown), or a prism of suitable material is placed under, alternate mirrors on the drum 14, Fig. 7 (not shown). To produce three interlaced sets of scanning- lines, a displacing-prism is applied to one mirror, and a similar prism reversed is applied to a second mirror of each group of three adjacent mirrors, Fig. 8 (not shown). To reproduce colours the faces of the low-speed scanner have colour filters producing a succession of colours.