Cathode ray tube for high screen loading applications - comprises silver activated blue luminescing zinc sulphide having hexagonal crystal structure of wurtzite

摘要

A cathode ray tube having a luminescent screen which is suitable for screen loads of more than 0.05 W cm-2 comprises a blue luminescing ZnS activated by Ag and co-activated by one or more of the elements Cl, Br, I, F, Al, Ga and In. The novelty is that the ZnS has the hexagonal crystal structure of zite and that the blue colour point can be readjusted by replacing up to 20 mol%. of the Zn by Cd and 20 mol% of the S at least one of Se and Te.