schaltungsanordnung in a farbfernsehempfaenger with a einstrahl - farbbildroehre synchronisation of variations in scanning with each to be sent farbbildpunkt

摘要

1,006,697. Oolour television tubes. G. VELENSI. Oct. 30, 1962 [Feb. 28, 1962; April 3, 1962; April 17, 1962; June 27, 1962], No. 40989/62. Heading H1D. [Also in Division H4] The invention is concerned with the problem of reducing non-linoarities present in the rate of scan of the electron beam in a colour television system (see Division H4), and is described in conjunction with cathode-ray tubes of the type comprising phosphor strips vertically arranged in groups of three (e.g. red, green, blue) which are scanned horizontally (type A, Fig. 1), and of the type comprising phosphor strips horizontally disposed in the sequence R G B G &c., which are scanned horizontally by a wobbling beam (type B, Fig. 3a), and also disclosed is a projection tube of type A (Fig. 2e). Broadly, some of the non-linearity present in the rate of scan is reduced by comparing signals derived from a set (type A) or sets (type B) of wires vertically disposed parallel and adjacent to the viewing screen with other pulses of a precise origin. Type A.-In the tube shown in Fig. 1 the single set of wire comprises a zig-zag S1-S8 brought out to a terminal bi is mounted on a frame a, b, c, d located on glass pads p. A further spring-tensioned single wire so serving to accurately locate the picture frame is brought out to a terminal bo. Type B, Fig. 3a.-Three sets of enamelled wires S1-S8, S1SP1/SP-S8SP1/SP and S1SP11/SP-S8SP11/SP are provided, the enamel being stripped away where the wire is located in front of the horizontallydisposed phosphor strip corresponding thereto. The wires are brought out to terminals b1, b1SP1/SP, b1SP11/SP which are connected via resistors R1, R1SP1/SP and R1SP11/SP of different value so that a characteristic signal amplitude is obtained determined by the colours of the phosphor on which the tubs beam impinges. Projection type tube, Fig. 2e.-The target K of the tube comprises a layer of ferro-electric crystals which exhibit bi-refringence when bombarded by the electron beam f, thus modulating the light beam produced by the source M which passes through polarizers A, P and the plate Rt which on its near side comprises vertically arranged groups of coloured phosphors and which on its far side comprises a plurality of elemental lenses corresponding in number to the phosphor strips and each focused on the light source. The additional gun pSP11/SP produces a dispersed beam of electrons F during the interframe period, thus creating a memory of the previous frame. S1-S8 and So comprise respectively a single set and a single wire as described with reference to Fig. 1 above.