Importance

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Abstract

There is provided white light illumination system including a radiation source, a first luminescent material having a peak emission wavelength of about 575 to about 620 nm, a second luminescent material having a peak emission wavelength of about 495 to about 550 nm, which is different from the first luminescent material and a third luminescent material having a peak emission wavelength of about 420 to about 480 nm, which is different from the first and second luminescent materials. The LED may be a UV LED and the luminescent materials may be a blend of three or four phosphors. The first phosphor may be an orange emitting Eu.sup.2+, M.sup.+ activated strontium pyrophosphate, Sr.sub.2 P.sub.2 O.sub.7 :Eu.sup.2+, Mn.sup.2+. The second phosphor may be a blue-green emitting Eu.sup.2+ activated barium silicate, (Ba,Sr,Ca).sub.2 SiO.sub.4 :Eu.sup.2+. The third phosphor may be a blue emitting SECA phosphor, (Sr,Ba,Ca).sub.5 (PO.sub.4).sub.3 Cl:Eu.sup.2+. Optionally, the fourth phosphor may be a red emitting Mn.sup.4+ activated magnesium fluorogermanate, 3.5MgO*0.5MgF.sub.2 *GeO.sub.2 :Mn.sup.4+. A human observer perceives the combination of the orange, blue-green, blue and/or red phosphor emissions as white light.

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First Claim