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Improved red phosphor Disclosure Number: IPCOM000028078D
Publication Date: 2004-Apr-22
Document File: 1 page(s) / 53K

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Improved red phosphor

    Yttrium oxide activated with europium (YOX) has been used as a red luminescent material in fluorescent lamps for many years. YOX is present in the luminescent layer that is present on the inner wall of the discharge vessel of these fluorescent lamps. In case such a fluorescent lamp comprises and outer bulb surrounding the discharge vessel, the outer bulb can cause a shift in colour point with respect to lamps not comprising such an outer bulb. The shift in the x-coordinate of the colour point of the light can be as high as 30 points. It has been found, however, that this shift in colour point does not occur when the europium content of the YOX is comparatively high (approximately 6.5 wt% Eu2 O3).

Disclosed anonymously.