GB359981A - Improvements in or relating to television and like apparatus - Google Patents

Abstract

359,981. Television. BAIRD, J. L. and TELEVISION, Ltd., 133, Long Acre, London. July 30. 1930, No. 23010. [Class 40 (iii).] For colour television in a system employing a receiver constituted by a bank of lamps of the type described in Specifications 222,604 and 291,121, [both in Class 40 (iii), Telegraphs, Electric], each single lamp is replaced by a set of filament lamps each of which emits light of a different colour. Transmitter. Light from a source 14 passes through apertures arranged in three contiguous spirals 11, 12, 13 on a disc 10, and is reflected from the object 15 to light-sensitive cells 16 arranged in a bank. The spirals 11, 12, 13 are covered with strips 17, 18, 19 of translucent material of different colours, e.g. red, green and blue, so that the object is successively scanned by beams of these colours. Receiver. The receiving screen is formed by sets of three lamps 24, 25, 26, each set being arranged in a cubicle formed by intersecting opaque partitions 22, 23. Corresponding lamps of the sets have their bulbs of glass of the same colour, and each set has bulbs of the three colours according to those employed at the transmitter. Each lamp of the set may be enclosed in a cubicle, and a translucent diffusing screen 27 is placed in front of the lamp bank. The signals from a receiving amplifier 37 are distributed to the appropriate lamps as illustrated diagrammatically in Fig. 3, by the cooperation of a switch arm 32 moving over segments 31 with an auxiliary selector switch 36 rotated over segments 33, 34, 35. Each segment 31 is connected to terminals of a set 30 of the lamps, whilst the segments 33, 34, 35 are individually connected to all lamps appropriate to a particular colour. The arm 32 is rotated three times as rapidly as the arm 36, and during each rotation effects the illumination of all the lamps of one of the three colours. In an alternative method, the arm 36 makes one revolution whilst the arm 32 contacts with a segment 31. In this case the lamps of each set are illuminated in succession, and the sets of lamps are successively actuated. The switching devices employed may be of the type illustrated in Figs. 1 and 2 of Specification 347,741. Synchronism and phase adjustment of the receiving system may be effected by the means described in Specifications 320,639 or 336,655, [both in Class 40 (iii), Telegraphs, Electric]. The signals may be sent over a number of separate channels and applied simultaneously to the lamps of a set, the selector device 33 .. 36 being unnecessary in this case. At the transmitting station the object may be Bood-lighted and explored in the manner described in Specification 283,957, [Class 40 (iii), Telegraphs, Electric]. Specifications 347,254 and 348,211 are also referred to.