GB1013989A - Cathode ray tube - Google Patents

Abstract

1,013,989. Colour television tubes. RADIO CORPORATION OF AMERICA. July 16, 1963 [Aug. 6, 1962], No. 28155/63. Heading H1D. In a plural-gun cathode-ray television tube of the type in which beams of different velocities penetrate to different extents into a superimposed phosphor layer screen, the separate electrostatic focusing systems are energized with the same voltages, thus reducing the number of lead-ins required, but are differently constructed/positioned to have the same focus ing strength. The transfer characteristics of the guns may also be made equal. In the Fig. shown, the spacings between the anodes 46, 50; 47, 51; and 48, 52 of the unpotential lens focusing systems are increased from the lowest velocity L gun to the highest velocity H gun while the spacing between the first anodes 46, 47, 48 and the control electrodes 42 is decreased. Also, the focus cylinders 54, 55 are equal in length and shorter than the focus cylinder 56. The focus cylinders 54, 55, 56 may be replaced by aperture discs differing in internal diameter, Fig. 6 (not shown). To equalize the transfer characteristics or to make them have a particular relationship not necessarily equal, the spacing between cathode and control electrode, or the diameter of the control electrode aperture, may be varied from gun to gun. In another embodiment, Fig. 7 (not shown), cup-shaped screen electrodes are provided between the control electrodes and the respective first anodes. The spacings between the respective anodes and the lengths of the respective first and second anodes are changed from gun to gun so that all the guns are of equal length. Also described are magnetic static and dynamic convergence systems, magnetic beam adjustment and shielding systems and a magnetic system for enhancing the deflection of the H beam in one direction relative to the deflection in the perpendicular direction.