Phosphor blend and fluorescent lamp containing same
View Patent ↗A phosphor blend is described wherein the blend consists of a red-emitting rare earth phosphor, a green-emitting rare earth phosphor, and a blue-emitting rare earth phosphor wherein the 50% size of the phosphors is between about 12 to 15 μm. The phosphor blend is incorporated into a fluorescent lamp having an increased efficacy. A dual layer coating may be used to provide an additional increase in efficacy.
1. A phosphor blend consisting of a red-emitting rare earth phosphor, a green-emitting rare earth phosphor, and a blue-emitting rare earth phosphor, wherein the blue-emitting rare earth phosphor is selected from the group consisting of BAM and SCAp, and wherein the median particle size of the red-emitting rare earth phosphor, the green-emitting rare earth phosphor, and the blue-emitting rare earth phosphor is between about 12 to 15 μm.
2. The phosphor blend of claim 1 wherein the red-emitting phosphor is a YOE phosphor and the green-emitting phosphor is at least one of a LAP, a CAT, or a CBT phosphor.
3. The phosphor blend of claim 1 wherein the red-emitting phosphor is a YOE phosphor, the green-emitting phosphor is a LAP phosphor and the blue-emitting phosphor is a BAM phosphor.
4. A fluorescent lamp, comprising: electrodes and a glass envelope having a phosphor coating on an interior surface, the envelope being hermetically sealed and containing an amount of mercury and an inert gas, the phosphor coating containing a phosphor blend consisting of a red-emitting rare earth phosphor, a green-emitting rare earth phosphor, and a blue-emitting rare earth phosphor, wherein the blue-emitting rare earth phosphor is selected from the group consisting of BAM and SCAp, and wherein the median particle size of the red-emitting rare earth phosphor, the green-emitting rare earth phosphor, and the blue-emitting rare earth phosphor is between about 12 to 15 μm.
5. The lamp of claim 4 wherein a powder weight of the phosphor blend is between 5 g and 7 g.
6. The lamp of claim 5 wherein the phosphor coating is applied in a single layer.
7. The lamp of claim 5 wherein the phosphor coating is applied as a dual layer.
8. The lamp of claim 7 wherein a first layer of the dual layer is between 40-60% by weight of the phosphor coating.
9. The lamp of claim 4 wherein the red-emitting phosphor is a YOE phosphor and the green-emitting phosphor is at least one of a LAP, a CAT, or a CBT phosphor.
10. The lamp of claim 4 wherein the red-emitting phosphor is a YOE phosphor, the green-emitting phosphor is a LAP phosphor and the blue-emitting phosphor is a BAM phosphor.
11. The lamp of claim 10 wherein a powder weight of the phosphor blend is between 5 g and 7 g.
12. The lamp of claim 11 wherein the phosphor coating is applied in a single layer.
13. The lamp of claim 11 wherein the phosphor coating is applied as a dual layer.
14. The lamp of claim 13 wherein a first layer of the dual layer is between 40-60% by weight of the phosphor coating.
15. A fluorescent lamp, comprising: electrodes and a glass envelope having a coating on an interior surface, the envelope being hermetically sealed and containing an amount of mercury and an inert gas, the coating consisting of a red-emitting rare earth phosphor, a green-emitting rare earth phosphor, and a blue-emitting rare earth phosphor, wherein the blue-emitting rare earth phosphor is selected from the group consisting of BAM and SCAp, and wherein the median particle size of the red-emitting rare earth phosphor, the green-emitting rare earth phosphor, and the blue-emitting rare earth phosphor is between about 12 to 15 μm.