GB1454568A - Electron gun assemblies for use in colour picture tubes - Google Patents

Abstract

1454568 Colour television tubes HITACHI Ltd 8 March 1974 [29 Aug 1973] 10509/74 Heading H1D A delta-type three-gun assembly for a colour television tube includes three sets of first and second grid electrodes 10 and 11, respectively, Fig. 3, followed by third and fourth grid electrodes 12 and 13, Figs. 4 and 6, each of which is in the form of a triangular cross-section cylinder, both end walls of electrode 12, and the adjacent end wall of electrode 13, being provided with three apertures corresponding to the three electrode sets 10 and 11. As shown, the apertures in grid 12 adjacent the second grid are formed in projections 17, while the subsequent apertures 20 and 21 have incurved edges 19. Apertures 21 are slightly outwardly displaced with respect to the apertures 20, such that the resulting lens action produces convergence of the three beams at the shadow mask of the tube. Alternatively, convergence may be produced by a convergence yoke, and reference is made to modified arrangements in which the first and second grid electrodes are each, like the third and fourth electrodes, of unitary construction, and to an assembly of uni-potential rather than of bipotential type.