Patent ID: 7199513

Claim:
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)MgAl 10 O 17 :Eu phosphor, a BaMgAl 10 O 17 :Eu phosphor, and a SrMgAl 10 O 17 :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.