Garnet phosphors, method of making the same, and application to semiconductor LED chips for manufacturing lighting devices
First Claim
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1. A garnet phosphor having the following composition:
- Re3(Al1-sGas)5O12;
Ce;
xMAl2O4 wherein Re is a rare earth selected from the group of yttrium, gadolinium, samarium, lutecium and ytterbium, s is equal to or greater than 0 and less than or equal to 1;
x is from 0.01 to 0.3, and M is an alkali or alkaline earth metal.
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Abstract
A cerium-doped garnet phosphor including a second phase of an alkali metal or alkaline earth metal aluminate. The second phase imparts improved emission efficiency but without changing the wavelength of emission. These phosphors are useful to form a white light source together with a blue or ultraviolet light-emitting LED. The phosphors are applied to the LED by forming a phosphor slurry with a polymerizable material in a solution, coating the exposed surface of the LED with a predetermined amount of the slurry, and polymerizing the polymerizable material.
52 Citations
18 Claims
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1. A garnet phosphor having the following composition:
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Re3(Al1-sGas)5O12;
Ce;
xMAl2O4wherein Re is a rare earth selected from the group of yttrium, gadolinium, samarium, lutecium and ytterbium, s is equal to or greater than 0 and less than or equal to 1;
x is from 0.01 to 0.3, and M is an alkali or alkaline earth metal.- View Dependent Claims (2, 3, 4, 5, 12, 13, 14, 15, 16, 17, 18)
b) mounting one or more semiconductor light emitting diodes that emit blue light on a frame;
c) coating the light emitting diodes with a predetermined amount of the phosphor slurry; and
d) polymerizing the polymerizable material.
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15. A method according to claim 14 wherein the polymerizable material is polyvinyl alcohol.
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16. A method according to claim 14 wherein the polymerizable material is polymerized with heat.
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17. A method according to claim 16 wherein the polyvinyl alcohol is polymerized by heating at about 130°
- C.
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18. A method according to claim 14 wherein the polymerizable material is polymerized by photoinitiation.
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6. A method of making a phosphor slurry comprising making a solution of a polymer or polymerizable material in a dispersion liquid, cooling it, adding a YAG:
- Ce phosphor powder and shaking to form a uniform slurry.
- View Dependent Claims (7, 8, 9, 10, 11)
Specification