Terbium-activated luminescent garnet material and mercury vapor discharge lamp containing the same
AssigneeU.S. Philips Corporation
InventorsJohannes Gerardus Verriet, Antonius Maria, Josephus, Hubertus Seuter
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Abstract
Terbium-activated luminescent material with garnet crystal structure satisfying the formula Ln .sub.3-x-p Tb.sub.p A.sub.5-x-2y Me.sup.II.sub.x+y Me.sup.IV.sub.x+y O.sub.12, wherein Ln represents yttrium, gadolinium and/or lutecium, A aluminium and/or gallium, Me.sup.II magnesium, calcium, strontium and/or zinc, and Me.sup.IV silicon, germanium and/or zirconium, and wherein: 0 .ltoreq. x .ltoreq. 2.8 0 .ltoreq. Y .ltoreq. 2.0 0.4 .ltoreq. x+y .ltoreq. 2.8 0.02 .ltoreq. P .ltoreq. 1.50 x+p .ltoreq. 3.0 is useful in low pressure mercury vapor discharge lamps.
Claims8
A terbium-activated luminescent material with garnet crystal structure, characterized in that the luminescent material satisfies the formula
- Ln.sub.3-x-p Tb.sub.p A.sub.5-x-2y Me.sup.II.sub.x+y Me.sup.IV.sub.x+y O.sub.12,
- wherein Ln represents at least one of the elements yttrium, gadolinium and lutecium, A is at least one of the elements aluminium and gallium, wherein upto 40 mole % of A is replaceable by scandium, Me.sup.II is at least one of the elements magnesium, calcium, strontium and zinc, and Me.sup.IV is at least one of the elements silicon, germanium and zirconium and wherein
- 0 .ltoreq. x .ltoreq. 2.8 0 .ltoreq. y .ltoreq. 2.0 0.4 .ltoreq. x+y .ltoreq. 2.8 0.02 .ltoreq. p .ltoreq. 1.50 x+p .ltoreq. 3.0
Dependencies are inferred from the claim text.