Foley & Lardner
White light emitting phosphor blends for LED devices
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 Eu2+, M+ activated strontium pyrophosphate, Sr2P2O7:Eu2+, Mn2+. The second phosphor may be a blue-green emitting Eu2+ activated barium silicate, (Ba,Sr,Ca)2SiO4:Eu2+. The third phosphor may be a blue emitting SECA phosphor, (Sr,Ba,Ca)5(PO4)3Cl:Eu2+. Optionally, the fourth phosphor may be a red emitting Mn4+ activated magnesium fluorogermanate, 3.5MgO*0.5MgF2*GeO2:Mn4+. A human observer perceives the combination of the orange, blue-green, blue and/or red phosphor emissions as white light.
General Electric Company
C H H Y H
C09K H01L H01L Y02B H01L
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Thomas Francis Alok Mani Holly Ann
McNulty Srivastava Comanzo