Fluorescent lamp construction utilizing a mixture of two phosphor materials

Claim 1

In a fluorescent lamp which includes a tubular shaped lamp glass envelope, an electrode structure at each end of said glass envelope, a mercury and inert gas filling within said envelope, and a phosphor coating on the interior surface of said glass envelope, the improvement which comprises using a blended phosphor mixture comprising a phosphor combination of a strontium haloapatite phosphor having the general formula: Sr.sub.10-x-y Sb.sub.x Mn.sub.y (PO.sub.4) . A.sub.2 wherein A is a halide ion selected from F and Cl including combinations thereof, x is in the approximate range 0.04-0.15, and y is in the approximate range 0.01-0.42 with europium-activated yttrium oxide phosphor, which phosphor combination produces a composite emission at a color temperature in the approximate range 2,700° K - 6,500° K with satisfactory color rendition and a higher luminous efficiency than is obtained with conventional deluxe phosphor blends, wherein the weight ratios for said phosphor combination is approximately 68-85 weight percent of the strontium haloapatite phosphor and approximately 32-15 weight percent of the europium-activated yttrium oxide phosphor.