Abstract A fluorescent lamp is provided on the inner wall surface of a sealed envelope with a first fluorescent layer including at least one fluorescent material selected from a group consisting of manganese activated magnesium fluorogermanate and manganese activated magnesium arsenate. On the first fluorescent layer is deposited a second fluorescent layer comprising a mixture of at least one fluorescent material selected from a group consisting of magnesium tungstate, calcium tungstate and antimony activated calcium halophosphate and at least one fluorescent material selected from a group consisting of tin activated strontiummagnesium-barium orthophosphate, tin activated calcium-strontium orthophosphate and calcium halophosphate activated with antimony and manganese. The thicknesses of the first layer and the second layer are respectively 21 + OR - 5 microns and 9 + OR - 5 microns.
A fluorescent lamp according to claim 1 wherein said at least one fluorescent material functioning to radiate the blue region and said at least one fluorescent material functioning to radiate the orange region are mixed together so as to satisfy the following equations: where x + or - 10 is the weight percentage of the former fluorescent material, while y - or + 10 is the weight percentage of the latter fluorescent material, respectively, based on the entire second fluorescent layer, and T represents the color temperature in *K of said fluorescent lamp and ranges between 3000 and 7000.
Claim 2
Dependent Claim
39 words
A fluorescent lamp according to claim 2 wherein said first fluorescent layer comprises 50 percent by weight of manganese-activated magnesium fluorogermanate and 50 percent by weight of manganese-activated magnesium fluorogermanate both percentages being based on said first fluorescent layer.
Claim 3
Dependent Claim
30 words
A fluorescent lamp according to claim 2 wherein said second fluorescent layer comprises 44 percent by weight of magnesium tungstate and 56 percent by weight of tin activated strontium-magnesium-barium orthophosphate.