Fluorescent colortone lamp with reduced mercury

Abstract

An electric lamp has an envelope with an inner surface and two electrodes located at each end of the envelope. The electrodes transfer electric power to generate ultraviolet radiation in the envelope which is filled with mercury and a charge sustaining gas. The inner surface of the envelope is pre-coated with an aluminum oxide layer to reflect ultraviolet radiation back into the envelope. A phosphor layer is formed over the aluminum oxide to convert the ultraviolet radiation to visible light. The phosphor layer is a mixture of four phosphors, namely, blue luminescing Blue Halophosphor (BH), red-luminescing Yittrium Oxide (YOX), 3000K-luminescing Calcium Halophosphor, also referred to as Warm White (WW) and green-luminescing Zinc Silicate (ZS).

Dependencies are inferred from the claim text.