VUV-excited device with blue-emitting phosphor
Blue-emitting phosphors for use with plasma display panels (PDP) or other vacuum ultraviolet-excited (VUV) devices are provided. These blue-emitting phosphors and mixtures thereof include at least a europium-activated calcium-substituted barium hexa-aluminate (CBAL) phosphor. Preferably, the CBAL phosphor has a composition which may be represented by the formula: Ba 1.29-x-y Ca x Eu y Al 12 O 19.29 , wherein 0<x<0.25 and 0.01<y<0.20. These blue-emitting phosphors exhibit improved degradation characteristics, including reduced color shift and increased intensity maintenance, under conditions found in VUV-excited devices.
1. A VUV-excited device including a discharge chamber with a phosphor coating, the discharge chamber containing a rare gas or rare gas mixture, the phosphor coating being applied to an inner surface of the discharge chamber, the device when operated generating a discharge which emits vacuum ultraviolet radiation as a primary source of excitation, the phosphor coating containing a europium-activated, calcium-substituted barium hexa-aluminate phosphor having a composition which is represented by Ba 1.29-x-y Ca x Eu y Al 12 O 19.29 , wherein 0<x<0.25 and 0.01<y<0.20.
2. The VUV-excited device of claim 1 wherein the europium-activated, calcium-substituted barium hexa-aluminate phosphor is coated with aluminum oxyhydroxide.
3. The VUV-excited device of claim 1 wherein the device generates a vacuum ultraviolet light having a wavelength of 147 nm to 173 nm.
4. The VUV-excited device of claim 1 wherein the discharge chamber contains xenon or a mixture of xenon and helium.
5. The VUV-excited device of claim 1 wherein the phosphor coating additionally contains a phosphor selected from the group consisting of europium-activated barium magnesium aluminate, europium-activated barium magnesium aluminate coated with aluminum oxyhydroxide, and (Gd,La)PO 4 :Tm,Li.
6. The VUV-excited device of claim 1 wherein the phosphor coating additionally contains a (Gd,La)PO 4 :Tm,Li phosphor and a ratio of the europium-activated, calcium-substituted barium hexa-aluminate phosphor to the (Gd,La)PO 4 :Tm,Li is in the range from 2:1 to 20:1 by weight.
7. A VUV-excited device including a discharge chamber with a phosphor coating, the discharge chamber containing a rare gas or rare gas mixture, the phosphor coating being applied to an inner surface of the discharge chamber, the device when operated generating a discharge which emits vacuum ultraviolet radiation as a primary source of excitation, the phosphor coating containing a europium-activated, calcium-substituted barium hexa-aluminate phosphor having a composition which is represented by Ba 1.29-x-y Ca x Eu y Al 12 O 19.29 , wherein 0<x<0.25 and 0.01<y<0.20 wherein the discharge chamber contains xenon or a mixture of xenon and helium, and wherein the device generates a vacuum ultraviolet light having a wavelength of 147 nm to 173 nm.
8. The VUV-excited device of claim 7 wherein the phosphor coating additionally contains a phosphor selected from the group consisting of europium-activated barium magnesium aluminate, europium-activated barium magnesium aluminate coated with aluminum oxyhydroxide, and (Gd,La)PO 4 :Tm,Li.
9. The VUV-excited device of claim 7 wherein the phosphor coating additionally contains a (Gd,La)PO 4 :Tm,Li phosphor and a ratio of the europium-activated, calcium-substituted barium hexa-aluminate phosphor to the (Gd,La)PO 4 :Tm,Li is in the range from 2:1 to 20:1 by weight.
10. The VUV-excited device of claim 7 wherein the europium-activated, calcium-substituted barium hexa-aluminate phosphor is coated with aluminum oxyhydroxide.
11. A method of generating blue light comprising exciting a blue-emitting phosphor with vacuum ultraviolet radiation, the blue-emitting phosphor comprising an europium-activated, calcium-substituted barium hexa-aluminate phosphor wherein the europium-activated, calcium-substituted barium hexa-aluminate phosphor has a composition which is represented by Ba 1.29-x-y Ca x Eu y Al 12 O 19.29 , wherein 0<x<0.25 and 0.01<y<0.20.
12. The method of claim 11 wherein the device generates a vacuum ultraviolet light having a wavelength of 147 nm to 173 nm.
13. The method of claim 11 wherein the phosphor coating additionally contains a phosphor selected from the group consisting of europium-activated barium magnesium aluminate, europium-activated barium magnesium aluminate coated with aluminum oxyhydroxide, and (Gd,La)PO 4 :Tm,Li.
14. The method of claim 11 wherein the phosphor coating additionally contains a (Gd,La)PO 4 :Tm,Li phosphor and a ratio of the europium-activated, calcium-substituted barium hexa-aluminate phosphor to the (Gd,La)PO 4 :Tm,Li is in the range from 2:1 to 20:1 by weight.
15. The method of claim 11 wherein the europium-activated, calcium-substituted barium hexa-aluminate phosphor is coated with aluminum oxyhydroxide.