Patent GB-1175698-A (GB)
Title: Colour Cathode Ray Tube
Inventor: SHIMADA SATOSHI
IPC: H01J31/20
Filed: 1966-12-23
Abstract: 1,175,698. Colour television tubes. SONY CORP. 23 Dec., 1966 [27 Dec., 1965 (2)], No. 57739/66. Heading H1D. [Also in Division H4] In a single beam colour television tube having a colour selection grid disposed adjacent the screen, the electron beam is cycled over the different colour phosphor strips by electrostatic deflection produced by two axially spaced pairs of opposed electrodes mounted on the outside of the neck of the tube, the inner surface of the tube being coated with corresponding high resistance layers which extend one opposite each electrode and which are A.C. coupled to earth; a composite A.C. voltage constituted by the sum of two frequencies, one a multiple of the other, and the waveform of one cycle of which exhibits a plutality of peaks, is applied both to the first pair of electrodes and, with reverse sense, to the second pair of electrodes, to cause successive deflections of the electron beam in opposite directions, such that for each signal peak the beam approaches the colour selection grid from a different direction and impinges upon a corresponding one of the sets of different colour strips. Two pairs of electrodes 9a, 9b and 10a, 10b which are coated on the outside of the tube neck are separated by insulant from a surrounding shield plate 24, and may extend beneath the magnetic deflection coils 14. High resistance layers 20 are coated on the inside of the tube beneath each electrode, the conductive layer 19 which is coated on the inside of the cone, and is held at a high potential, extending to the gun 4 along the gap 22, Fig. 3, between the high resistance layers 20, and also into the annular zone 23 between those layers. The screen 16 is coated with phosphor strips RGB and has an adjacent colour selection grid 17 composed of wires 17a disposed opposite the GB demarcation lines. The gun 4 is supplied with a high-frequency luminance signal Yh together with a chrominance signal C 8  from amplifier 6, and with a low frequency luminance signal YL from amplifier 5. Signal C s  is also fed to a colour burst separator 7 which also receives the horizontal deflection signal from circuit 8. The output from circuit 7 is fed to a colour switching signal generator 15 which supplies a sinusoidal signal of frequency # s  to key-out signal generator 12, which superimposes a 3# s  key-out signal upon the signal Y L  applied to the gun 4. The signal # s  is also applied to electrodes 9b and 10a, and to a multiplier 11 which provides a signal 2# s  to electrodes 9a and 10b, whereby the sum of # s  and 2# s  signals-forming the colour switching signal 31, Fig. 5-appears, with opposite senses, across the electrode pairs 9a, 9b and 10a, 10b. The electron beam is arranged to strike the red phosphor strips for the zero value 3IR of the signal 31, and, by successive oppositely directed deflection by the electrode pairs 9a, 9b and 10a, 10b, to strike the blue strips at the positive signal peak, and the green at the negative peak. The arrangement is stated to be applicable both to line sequential and to dot sequential systems.