FLUORESCENT LAMP CONSTRUCTION UTILIZING A MIXTURE OF TWO PHOSPHOR MATERIALS

A fluorescent lamp construction uses a particular blended phosphor mixture to provide an efficient light source having good color rendition. The phosphor mixture uses a blend of a strontium-haloapatite phosphor with europium-activated yttrium oxide phosphor. The phosphor mixture produces light emission in a color temperature range from about 2,700.degree.K to about 6,500.degree.K with both a satisfactory color rendition and higher luminous efficiency than can be obtained with conventional phosphor mixtures. The useful strontium-haloapatite phosphors include strontium blue halophosphate phosphor activated with antimony, strontium green halophosphate phosphor coactivated with antimony and manganese, and strontium yellow halophosphate phosphor which contains a still greater manganese activator level. The useful strontium-haloapatite phosphor have the general formula: Sr10-x-ySbxMny(PO4)6.A2 wherein A is a halide selected from F and C1 including combinations thereof, x is in the approximate range 0.04 to 0.15, and y is in the approximate range 0.01 to 0.42. The phosphor mixture contains approximately 75 to 85 weight percent of the strontium-haloapatite phosphor.