GB1153754A - Cathodoluminescent Screens - Google Patents

Abstract

1,153,754. Luminescent materials. SYLVANIA ELECTRIC PRODUCTS Inc. 10 June, 1966 [16 June, 1965], No. 26034/66. Heading C4S. [Also in Division H1] In a cathodoluminescent colour system for a cathode ray tube comprising compatible red, green and blue colour emitting phosphors applied to a screen or screens in a predetermined pattern which provides a cadmiumfree tri-colour phosphor system of white body colour, the green-emitting phosphor is a zinc sulphide-zinc selenide host activated with silver, the red-emitting phosphor is a rare earth host compound comprising the vanadate or oxide of yttrium, gadolinium or lutecium activated with at least one of the lanthanide rare earth elements europium and samarium, and the blue-emitting phosphor is a zinc sulphide host activated with silver. Preferably the amount of zinc selenide in the zinc sulphidezinc selenide host is within the range from 5 to 80 mole per cent and the amount of silver activator ranges from 0À001 to 0À10 per cent by weight. The red emitting phosphor may contain from 0À1 to 20À0 mole per cent of europium or samarium as activator and the blueemitting phosphor up to 0À050 mole per cent of silver as activator. The phosphors may be applied to the face-plate by photographic printing-ducting techniques or by slurry techniques. The individual primary phosphors may be disposed on separate screens in individual tubes to provide a plurality of additive primary colour images, which by optical means, may be superimposed to produce a multicolour display.