GB777936A - Improvements in and relating to colour switching circuits including reflector type colour television receiver tubes - Google Patents

Abstract

777,936. Colour television tubes. GENERAL ELECTRIC CO. July 23, 1953 [July 24, 1952]. No. 20469/53. Class 39(1). [Also in Group XL(c)] The colour switching circuit of a cathode ray receiver of the reflex type is such that the colour switching voltage is applied between the gun on one hand and the reflector and screen electrodes on the other hand, while the potential difference between screen and reflector is always constant. In one form, Fig. 1 (not shown) the colour switching voltage is applied between the gun on one hand and to the second anode and reflector on the other hand, the second anode being connected through the metal cone to the screen. In a modification, Fig. 2, the circuit allows the average beam intensity to be increased when the beam strikes the red phosphor to compensate for the lower luminosity of the red phosphor as compared with the green and blue phosphors and differences between the luminosities of the green and blue phosphors can also be compensated in this manner. This is done by using a stepped colour switching waveform applied at 31, 32 so that due to top 41 the potential of the first anode varies relatively to the cathode and control electrode. In another form, Fig. 4, a condenser 43 helps to ensure that there is no varying potential component between the screen and reflector. The second anode 19 is connected by spring fingers to wall coating 14 and cylindrical insulators space and support the gun electrodes. Specifications 713,875 and 726,214 are referred to.