Terbium-activated alkaline-earth metal silicate phosphors
AssigneeHitachi, Ltd.
InventorsTeruki Suzuki, Shinkichi Tanimizu, Yukio Ohno
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Abstract
A phosphor system consisting of an alkaline-earth metal silicate host lattice activated by trivalent terbium together with monovalent alkaline metal as a charge compensator, said phosphor system corresponding to the formula, X.sub.3-x Y.sub.1-x Si.sub.2 O.sub.8 : Tb.sub.x, Z.sub.x wherein X is at least one of Ba, Sr, and Ca; Y is at least one of Mg and Zn; and Z acting as a charge compensator is at least one of Li, K, and Na, and x is from 0.001 to 0.95, said phosphor system substituting Ca plus Mg for X plus Y of the formula being excluded. The present invention provides an efficient green-emitting phosphor particularly useful for a deluxe fluorescent lamp.
Claims11
A phosphor composition which comprises an alkaline-earth metal silicate host lattice activated by trivalent terbium together with monovalent alkaline metal as a charge compensator, said phosphor composition corresponding to the formula, X.sub.3-x Y.sub.1-x Si.sub.2 O.sub.8 :
- Tb.sub.x, Z.sub.x wherein X is at least one of Ba, Sr, and Ca;
- Y is at least one of Mg and Zn;
- and Z acting as a charge compensator is at least one of Li, K, and Na, and x is from 0.001 to 0.95, calcium of the elements represented by X being in an amount of not more than 10% by mole.
A phosphor composition which comprises an alkaline-earth metal silicate host lattice activated by trivalent terbium together with monovalent alkaline metal as a charge compensator, said phosphor composition corresponding to the chemical composition formula:
- Ba.sub.2.7075 Ca.sub.0.1425 Mg.sub.0.85 Si.sub.2.1 O.sub.8.4 :
- Tb.sub.0.15, Li.sub.0.15.
A phosphor composition which comprises an alkaline-earth metal silicate host lattice activated by trivalent terbium together with monovalent alkaline metal as a charge compensator, said phosphor composition corresponding to the formula, X.sub.3-x Y.sub.1-x Si.sub.2 O.sub.8 :
- Tb.sub.x, Z.sub.x' wherein X is at least one of Ba, Sr, and Ca;
- Y is at least one of Mg and Zn;
- and Z acting as a charge compensator is at least one of Li, K, and Na, and x is from 0.001 to 0.95, and x' is from x to 0.3x, calcium of the elements represented by X being in an amount of not more than 10% by mole.
A phosphor composition which comprises an alkaline-earth metal silicate host lattice activated by trivalent terbium together with monovalent alkaline metal as a charge compensator, said phosphor composition corresponding to the formula, X.sub.3-x Y.sub.1-x Si.sub.2 O.sub.8 :
- Tb.sub.x, Z.sub.x wherein X is at least one of Ba and Sr;
- Y is at least one of Mg and Zn;
- and Z acting as a charge compensator is at least one of Li, K and Na, and x is from 0.001 to 0.95.
Dependencies are inferred from the claim text.