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US 7,199,513 B2Granted
Discharge lamp having two-band phosphor
AssigneePatent-Treuhand-Gesellschaft fuer elektrische Gluehlampen mbH
InventorsGünter Huber, Frank Jermann, Ulrich Müller, Martin Zachau
Life of this patent
Estimating the term…
Abstract
A discharge lamp (1) having a discharge vessel (2) that surrounds a discharge medium that emits electromagnetic radiation in the VUV region during operation of the lamp, has on the inner side of the discharge vessel wall a yellow phosphor layer facing the discharge medium, and a blue phosphor layer lying therebelow. By contrast with a conventional three-band phosphor mixture, a higher luminous flux and a smaller color locus displacement are thereby achieved.
Claims3
A discharge lamp, comprising:
- a discharge vessel containing a discharge medium, the discharge medium emitting VUV electromagnetic radiation during operation of the lamp;
- and
- first and second phosphor layers, the first phosphor layer comprising a phosphor selected from a (Ba,Sr)MgAl10O17:Eu phosphor, a BaMgAl10O17:Eu phosphor, and a SrMgAl10O17:Eu phosphor, the second phosphor layer comprising a (Y,Gd,Tb)AG:Ce phosphor, wherein the second phosphor layer is applied to a wall of the discharge vessel and the first phosphor layer is applied over the second phosphor layer so that the first phosphor layer is between the discharge medium and the second phosphor layer, the first phosphor layer having a thickness that is sufficient to essentially completely absorb the VUV radiation from the discharge medium whereby the (Y,Gd,Tb)AG:Ce phosphor in the second phosphor layer is excited exclusively by blue radiation emitted from the first phosphor layer.
Dependencies are inferred from the claim text.