To prevent deterioration of a phosphor caused by excitation by UVradiation by including catena polyphosphate of at least one of alkali earth metals, zinc, cadmium, and manganese in a coating.
Preferably, UV-phosphor is aluminate phosphor, and a catena polyphosphate has 3-90 chain length. A coating contains catena polyphosphate of alkali earth metals, and 0.1-20 wt.% catena polyphosphate of zinc, cadmium, and manganese, and the alkali earth metals are preferable to be calcium, strontium, and barium. More preferably, the coating contains 5 wt.% zinc-catena polyphosphate and/or 5 wt.% manganese catena polyphosphate. Catena polyphosphate anhydride forms a firm coating insoluble in water on phosphor particles, and does not react with the UV-phosphor.
CZARNOJAN WOLFRAM
MAYR WALTER
JUESTEL THOMAS DR
NIKOL HANS DR
RONDA CORNELIS DR
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