Colouring phosphor particle surface with pigment - by addn. of adhesion promoter and then pigment suspension contg. organic binder to phosphor suspension

摘要

Application of coloured pigments (I) to the surface of coloured phosphor particles (II) for colour picture tube screens involves adding a (I) suspension contg. an organic binder (III) to an aq. (II) suspension. The novelty is that an adhesion promoter (IV) flocculating (III) is added to the (II) suspension first, to improve the adhesion of (I) to (II). Pref. (III) is PVA and (IV) boric acid, congo red, tannin, tetraborate etc. The phosphor may be applied to the screen photochemically. Suitable (I) are based on Cd(SSe) or Fe2O3 for red-emitting phosphors and ultramarine or Co aluminate for blue-emitting phosphors.