Beryllium-containing europium activated phosphate phosphor, luminescent screen and discharge lamp containing same
AssigneeU.S. Philips Corporation
InventorsJudicus Marinus Pieter Jan Verstegen, Willebrordus Hubertus Martinus Maria VAN DE Spijker, Emiel Petrus Juliaan DE Meester
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Abstract
A luminescent beryllium-containing phosphate activated by bivalent europium defined by the formula Me.sub.a-x Be.sub.b Eu.sub.x P.sub.2 O.sub.8 where a + b = 3 and 0.01.ltoreq.x.ltoreq.0.25 and b has the value 1 or 2. If b = 2, Me mainly represents one of the alkaline earth metals barium, strontium and calcium. If b = 1, Me mainly represents barium and/or strontium. The luminescent phosphate may be used in mercury vapor discharge lamps and in low-pressure cadmium vapor discharge lamps.
Claims14
A luminescent screen provided with a luminescent beryllium-containing phosphate, wherein the phosphate is activated by bivalent europium and is defined by the formula Me.sub.a-x Be.sub.b Eu.sub.x P.sub.2 O.sub.8 where a + b = 3, 0.01 .ltoreq. x .ltoreq. 0.25, and b has the value of 1 or 2 and in which, if b = 2, Me represents barium and in which, if b = 1, Me represents at least one of the alkaline earth metals selected from the group consisting of barium and strontium.
A luminescent beryllium-containing phosphate activated by bivalent bivalent europium and defined by the formula:
- Me.sub.2-x Be.sub.b Eu.sub.x P.sub.2 O.sub.8 in which a + b = 3, 0.01 .ltoreq. x .ltoreq. 0.25 and b has the value 1 or 2, in which, if b = 2, Me is barium and in which, if b = 1, Me is at least one of the alkaline earth metals selected from the group consisting of barium and strontium.
Dependencies are inferred from the claim text.